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ACKNOWLEDGMENTS The contents of this manual have been adapted from a number of sources including the previous Primary Science Safety Manual and Queensland Safety Handbook for Schools — Science, handbooks of other state education departments, and material from government agencies. These sources are gratefully acknowledged. All efforts were made to check that the information provided was accurate and current at the time of publication. New legislation and regulations may be enacted from time to time. New information regarding equipment and chemicals may become available. Emergency procedures may be revised. It remains the principal's responsibility to check for the latest information regarding legislation, regulations, policy and procedures that might affect a science activity. These guidelines were prepared by the Education Services Directorate. Representatives from many sectors of the department, tertiary institutions and professional associations have contributed to the development of this document. Questions about this reference manual should be directed to the Education Services Directorate, Education Queensland, PO Box 33, Brisbane Albert Street, Q 4002.

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CONTENTS Please Note: page numbering on this electronic copy may differ from the hard copy. 1.

GENERAL INTRODUCTION ................................................................................ 8

1.1

Law ........................................................................................................................... 9 1.1.1 1.1.2 1.1.3

1.1.4

Workplace Health and Safety Act 1995 Teacher responsibility Risk assessment and risk management 1.1.3.1 Risk management principles 1.1.3.2 Hazard identification 1.1.3.3 Risk assessment 1.1.3.4 Risk levels 1.1.3.5 Risk control Implications

2.

SCIENCE MANAGEMENT PROCESSES ............................................................ 14

2.1

Safety in science education ......................................................................................... 14 2.1.1 2.1.2 2.1.3

2.1.4 2.1.5 2.2

Fire ........................................................................................................................... 17 2.2.1 2.2.2

2.2.3

2.3

Introduction Teacher’s role Reducing the risks • Understanding • Preparation • Organisation • Supervision • Experimental practices • Correct labelling Accident procedure First aid

Nature of fires Prevention of fires • Sources of ignition • Gas installations • Flammable substances • Flammable liquids • Flammable gases • Combustible solids • Electrical fires • Some teaching of science area practices Action in case of fire • Equipment • Evacuation

Poisons ...................................................................................................................... 21 2.3.1 2.3.2

Introduction Toxicity 3

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• Definition of terms

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2.3.3 2.3.4

2.3.5 2.3.6

2.3.7 2.3.8 2.3.9 2.4

Toxicity and fire hazards associated with certain acid anion compounds Skin contamination • Skin contamination — except phenolics • Skin contamination — phenolics Gas or vapour inhalation Chemicals swallowed • Treatment for an unconscious patient • Treatment for a conscious patient Toxicity of certain metals and metal compounds Hazards associated with certain gases Alphabetical list of poisons and first aid

Equipment ................................................................................................................. 31 2.4.1

2.4.2

2.4.3

2.4.4

2.4.5 2.4.6

Gas installations and inspections • Portable gas bottles • Permanent gas installations • Isolation valves Electrical outlets and equipment • Electrical outlets • Commercial electrical equipment Eye washing and safety shower • Eye washing • Safety shower Fume cupboards • Mechanical • Heat-induced convection • Diffusion Water stills Penetrating objects  carbon dioxide syphon bulbs

3.

CHEMICAL MANAGEMENT .............................................................................. 35

3.1

Organisation .............................................................................................................. 35 3.1.1 3.1.2 3.1.3 3.1.4 3.1.5

Introduction Prevention of personal injury Chemicals used in schools for the teaching of science Chemical stocks Storage of chemicals 3.1.5.1 General handling and storage precautions 3.1.5.2 Storage of chemicals in plastic containers 3.1.5.3 Special handling and storage precautions − Concentrated acids − Flammable liquids − Other solvents or liquids − Powerful oxidising agents − Incompatible substances − Other chemicals (carbon disulfide, phosphorus, diethyl ether, sodium, mercury) 5

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3.1.6

Chemical spills procedure 3.1.6.1 General procedures

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3.1.7

3.2

Disposal of chemicals: 3.1.7.1 General principles −Acids/alkalis −Flammable liquids −Solids −Unwanted chemicals 3.1.7.2 Methods of disposal −Method of disposal codes (Table 1) −Disposal information (Table 2) 3.1.7.3 Transportation of chemicals −Transport of chemicals by road and rail −Transport of chemicals by sea −Maximum quantities per container (Table 3) −Chemicals requiring Emergency Procedures Guide (EPG) (Table 4) −Shipping documentation (Table 5)

Preparation of solutions and stains ............................................................................... 60 3.2.1

3.2.2

3.2.3

3.2.4

3.2.5

Calculations and techniques 3.2.1.1 Conversion factors 3.2.1.2 A technique for determining mass 3.2.1.3 A technique for determining mass with greater precision Solution preparation 3.2.2.1 Preparing stock solutions including acids and alkalis 3.2.2.2 Preparation instructions (Table 6) 3.2.2.3 Variant concentrations and volumes (Table 7) 3.2.2.4 Series dilutions (Table 8) Some useful chemical indicators −Cobalt chloride paper −Phenyl thiocarbamide (PTC) paper −Universal indicator −Orcinol-Bial’s Reagent −Red cabbage Some useful biological solvents, adhesives, stains, fixatives and buffer solutions 3.2.4.1 General purpose solutions 3.2.4.2 Adhesives 3.2.4.3 Stains 3.2.4.4 Fixatives 3.2.4.5 Buffer solutions Recent changes to Workplace Health and Safety Legislation

3.3

Material Safety Data Sheets ....................................................................................... 78 3.3.1 Labels 3.3.2 Labelling of small containers

3.4

Chemical nomenclature .............................................................................................. 80

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4.

ELECTRICAL HAZARDS ..................................................................................... 90

4.1

Electric shock ............................................................................................................ 90 4.1.1 4.1.2 4.1.3

4.2

Effects of electric current passing through the human body ‘Let-go’ current Causes of electric current passing through the human body

Safe practices and procedures .................................................................................... 93 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.2.7 4.2.8 4.2.9 4.2.10

Power points and switches Mains operated equipment Leads Electrical inspections Reporting an accident Isolating transformers Precautions to take when using an isolating transformer Core balance earth leakage devices Legislation affecting electrical safety Management of electric shock victims

4.3

Further electrical data ................................................................................................. 98

5.

RADIATION HAZARDS ....................................................................................... 99

5.1

Radioactive substances ............................................................................................... 99

5.2

Modes of radiation exposure ..................................................................................... 100

5.3

Radioactive sources ................................................................................................. 101

5.4

Cold cathode tubes  discharge tubes ...................................................................... 101

5.5

Lasers ..................................................................................................................... 102 5.5.1 5.5.2

Class 1 lasers Class 2 lasers 5.5.2.1 Responsibility 5.5.2.2 Screens or shields

6.

PLANT AND ANIMAL HAZARDS ..................................................................... 106

6.1

Biological activities ................................................................................................... 106 6.1.1 6.1.2

6.2

Teacher responsibilities Biological risks

Cultures and micro-organisms ................................................................................... 107 6.2.1 6.2.2 6.2.3 6.2.4

Personal protection Exposure of agar plates Sterilisation Disposal

6.3

Hazardous animals ................................................................................................... 108

6.4

Summary of treatments for some animals .................................................................. 115 6.4.1 6.4.2

Bites and stings Other envenomation 8

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6.5

Hazardous plants .......................................................................................................117

6.6

Summary of treatments for some plants ..................................................................... 120

6.7

Blood, blood products, body fluids .............................................................................. 121 6.7.1 6.7.2 6.7.3

6.8

Live animals ............................................................................................................ 122 6.8.1 6.8.2

6.9

Personal protection Spills Waste disposal

Risks Collection of live animals

Dissections .............................................................................................................. 123 6.9.1

The Care and Use of Animals in Schools—Policy and Guidelines

7.

SCIENCE FACILITIES AND EQUIPMENT ...................................................... 140

7.1

The role and duties of the secondary-school scientific assistant ................................... 140

7.2

General guidelines for the care of science facilities and equipment ............................... 141 7.2.1 7.2.2 7.2.3 7.2.4 7.2.5 7.2.6 7.2.7 7.2.8 7.2.9 7.2.10 7.2.11 7.2.12 7.2.13

8.

Cleaning Constructing and preparing apparatus Unpacking, checking and sorting new equipment Stock control Razor blades Using a Gas-Pak Making a candle in a holder Lighting the bunsen burner Using bunsen burners Glassware Putting tubing into a stopper Thermometers Dangers from the sun

GLOSSARY

………………………………………………………………… 156

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1. GENERAL INTRODUCTION Workplace Health and Safety Act requirements, risk assessment and risk management policy, social justice policy, and principles of effective learning and teaching all have an impact on the safe, effective and accountable management of practical activities occurring in science activities. Science activities involve the use of hazardous materials, which must be handled, stored, used and disposed of carefully. In the interests of both safety and economy, efficient and responsible methods of using and accounting for all substances and equipment in laboratories must be established. This handbook contains information on aspects of safe and efficient management of practical science activities, laboratories and other science activity areas, equipment and materials. The information is useful for both primary and secondary teachers. Teachers from other teaching areas within the school may need to refer to this manual for information that is pertinent to the safe use of science-related materials within their teaching area. This material has been abstracted from other documents, such as the Material Safety Data Sheets (MSDS), which are the definitive documents on using and storing chemical products safely. Every care has been taken to faithfully represent these other documents; however, reference should be made to the original source for additional and/or current information. Reference must be made to the Department of Education Manual (DOEM) • HS-10: Workplace Health and Safety Guidelines  Curriculum  Core Module. • HS-10/1 to HS-10/121: Workplace Health and Safety Guidelines  Curriculum  Activity Modules. • HS-11: Workplace Health and Safety Guidelines  Miscellaneous Safety Issues. Science-related DOEM modules include: • Safe Operation of Laboratory Equipment (HS-10/47); • Handling Live Animals  Science (HS-10/48); • Biological Activities (HS-10/49); • Chemical Hazards  Science (HS-10/50); • Management and Storage of Hazardous Science Substances (HS-10/51); • Maintenance and Operation of a Safe Laboratory (HS-10/52); • Maintenance and Operation of a Safe Work Area Outside the Laboratory (HS10/53); • Safe Work Practices Conducting Science Activities(HS-10/54); • Health and Safety First Aid (HS-14); • Accident and/or Incidents  Reporting and Investigation(HS-08). Other activity modules that might be applicable to science-related activities could include those related to camping, boating, fishing, swimming, gardening, maintaining a safe workshop, and welding.

Note: For teachers of science in a primary school setting: A significant amount of the information contained in this publication relates specifically to a secondary school context. However, the issues of science safety and management contained herein require close scrutiny and observation by all teachers, regardless of the educational setting.

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1.1 LAW 1.1.1

WORKPLACE HEALTH AND SAFETY ACT 1995

Education Queensland is committed to provid ing and maintaining a healthy and safe work and learning environment for all employees, students and others. The department has a statutory responsibility under the Workplace Health and Safety Act 1995 to ensure the risk of disease or injury from the school or workplace is minimised for all persons in contact with the school or other departmental workplace. Principals, teachers, and all other employees and people at a school have an obligation for ensuring workplace health and safety at the school. In particular, the Workplace Health and Safety Act 1995 places a statutory obligation on employees and other people at school to follow instructions for workplace health and safety, use of personal protective equipment and, in general, for responsible behaviour regarding workplace health and safety while at school or involved in school activities. Obligations for workplace health and safety should be ensured by: (a) (b) (c) (d) (e)

1.1.2

identifying hazards; assessing risks that may result because of the hazards; deciding on control measures to prevent, or minimise the level of, risks; implementing control measures; monitoring and reviewing the effectiveness of the measures.

TEACHER RESPONSIBILITY

In accordance with the Department of Education Manual module HS-07: Occupational Health and Safety, teachers are responsible for the health and safety of students while they are on school premises and participating in official school activities, wherever these may take place. Teachers and leaders should: (a) (b)

(c) (d)

(e) (f) (g)

(h)

maintain healthy and safe procedures and practices; collaborate with Regional Occupational Health and Safety Advisers, employees, workplace health and safety representatives or workplace health and safety committees to assess hazards which exist in the school or workplace and to eliminate or reduce the associated risks as required; identify hazards and minimise risks in science teaching areas; ensure that employees, students and other users of educational facilities receive appropriate workplace health and safety information and training (see your School Health and Safety Adviser); take care to ensure that appropriate use is made of all safeguards, safety devices, personal protective equipment and other appliances provided for the purpose of health and safety; manage behaviour of students (including during schoolground and excursion activities); ensure all work injuries, work-related illnesses and dangerous occurrences at the workplace are recorded. Such records are to be completed and dispatched to the appropriate authorities within the designated period (refer to HS-08: Accidents and/or Incidents  Reporting and Investigation in the Department of Education Manual); ensure special-needs groups (e.g. people with disabilities and persons from non-Englishspeaking backgrounds) are considered in regard to workplace health and safety issues (refer to HS-07: Occupational Health and Safety in the Department of Education Manual).

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1.1.3

RISK ASSESSMENT AND RISK MANAGEMENT

1.1.3.1

RISK MANAGEMENT PRINCIPLES

When evaluating health and safety factors in the teaching of science, teachers should apply the risk management process. The hazards in an area for the teaching of science (i.e. any room, laboratory, schoolground or field trip location, including factories, shops, farms or ‘nature’ areas, demonstration and experiment areas) need to be identified and the risks assessed and controlled, so that the teaching of science and the science activities conducted are as safe as is reasonably achievable. The process of identifying hazards, assessing risks and developing control measures is called risk management. Teachers of science must apply the following components of the risk management process: (a) (b) (c) (d)

identifying the hazards (hazard identification) (possible sources of injury or disease); assessing the risk level (risk assessment) (likelihood of the hazard resulting in injury or disease); controlling the risk (risk control) (determining what action to take to remove or reduce the risk); and reviewing and evaluating control (to ensure continued effectiveness).

This process is detailed in the HS-10: Workplace Health and Safety Guidelines  Curriculum  Core. The booklet Elements of a Laboratory Health and Safety Management System from the Division of Workplace Health and Safety is a useful reference for teachers.

1.1.3.2

HAZARD IDENTIFICATION

Hazards can be identified by a number of methods. These include: (a) (b) (c) (d) (e) (f)

a walk-through inspection of areas for the teaching of science including classrooms, laboratories, storage and preparation areas, and field sites; school accident/incident records revealing a pattern of safe/unsafe practices; evaluation of practices, i.e. an examination and discussion of particular activities, processes and protocols followed in school science activities; consultation with school personnel and students involved in science activities in particular areas for the teaching of science; Material Safety Data Sheets, product labels, manufacturers' specifications and manuals and other sources of technical information; consultation with specialist practitioners, including Occupational Health and Safety Advisers, local emergency-services personnel, doctors, officers of appropriate government and nongovernment agencies, science teachers' associations and other professional bodies. To identify the hazards in a school area for the teaching of science or science activity, all elements contributing to a hazardous situation must be identified. These elements include: People There should be consideration of all persons involved in the activity, or near the activity or area for the teaching of science  students, school personnel, visitors, other students and teachers, and members of the public. Are they aware of the appropriate health and safety requirements? Are there any groups susceptible to particular hazards, e.g. pregnant females being exposed to foetotoxic substances, or epileptics to strobe lights? Procedures

There should be consideration of the procedures followed in an activity and whether they involve direct student contact and involvement, teacher contact and involvement, teacher demonstration and/or have an impact on others who may be nearby or who will use a classroom or other area for teaching 12

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science after the conclusion of that activity. Procedures involving the production of gases or storage –handling–disposal are examples of procedures that might affect other school persons not directly involved in a science activity. Materials

Reactants, products and by-products; their toxicity, flammability and reactivity are examples of hazards that should be considered.

Processes

Some processes generate new hazards, e.g. an explosion.

Machines

Machines and equipment can generate noise, heat or electrical charges/voltages and may pose mechanical risks because of exposed cogs, wheels and drive belts.

Workplace

The workplace environment can increase the risk level because of poor lighting, narrow access pathways and confined spaces, inappropriate floor surfaces and other such features of the room and its appointments.

The process of hazard identification in areas for the teaching of science or science activities should start by appropriate school personnel reading the Workplace Health and Safety Guidelines  Curriculum  Core Module and relevant activity modules of the Department of Education Manual and consulting the Material Safety Data Sheets. This manual, Aspects of Science Management: A Reference Manual for Schools, provides additional technical and management information from a variety of sources that can help school personnel enact the policy guidelines of the DOEM. Other sources of appropriate information include operators’ manuals and instructions provided with laboratory equipment, textbooks and accompanying laboratory manuals, journals, safety authority publications, and printed information provided by electrical authorities, medical and emergency services, and local, State and Commonwealth Government departments and agencies. Reviews of school accident records and meetings with representatives of other schools will also help in identifying potential hazards. The following hazard categories might be encountered in school science activities: • • • • • • • •

chemical hazards (storage); chemical hazards (use); microbiological hazards; mechanical hazards; ionising radiation hazards; electrical hazards; non-ionising radiation hazards; and penetrating objects.

Teachers of science are reminded to refer to the hazards section in paragraphs 2.7 to 2.23 of HS-10: Workplace Health and Safety  Curriculum  Core M odule in the Department of Education Manual.

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1.1.3.3

RISK ASSESSMENT

Once a hazard has been identified, the consequences associated with it need to be determined. In schools, the most likely effects to consider would be those that involve direct injury, e.g. cuts, burns, electrocution and poisoning. Less likely effects might also include those arising from longer-term exposure, e.g. exposure to asbestos-containing materials. Risk assessments may vary in complexity depending on the nature and location of the hazardous situation, the personnel and equipment available, and the age and number of students present. The underlying principle of all risk assessments is the consideration of consequences of the hazardous outcome and the probability or frequency of the occurrence. In general, when a learning/teaching activity occurs in the teaching of science, the risk is related to: • • •

the probability of an injury or illness occurring; the duration and frequency of exposure to the hazard; and the consequence or outcome of something going wrong.

There are two major types of risk assessment. The first relates to potential effects of hazards that are immediate or acute. These include hazards that are mechanical, electrical, penetrating injuries and some forms of manual handling. The second relates to potential effects of hazards that are chronic or long-term. These include hazards that involve noise, hazardous substances/chemicals, repetitive movements and constrained postures. Teachers of science should refer to the relevant risk assessment details in HS-10: Workplace Health and Safety  Curriculum  Core Module in the Department of Education Manual. 1.1.3.4 RISK LEVELS HS-10: Workplace Health and Safety  Curriculum  Core Module outlines the risk level categories according to the nature of the activity. Different levels or categories have been determined in the activity modules to reflect the approximate level of risk involved or the degree of complexity encountered in the activity. The level of risk will vary from school to school, depending on: (a) (b) (c) (d)

expertise of teacher; size of student group; diversity of students; and facilities and equipment.

The risk levels in the teaching of science are determined by: (a) identifying the hazards associated with the materials used in the activity; (b) examining the complexity of the activity; (c) determining the severity of the consequences of any potential accident; (d) evaluating the risks associated with the environment and/or equipment being used; (e) evaluating the knowle dge and ability of the persons involved to safely undertake the activity. The risk levels applicable when categorising activities involving the teaching of science are low risk (level 1), medium risk (level 2), high risk (level 3) and very high risk (level 4). Teachers of science should refer to the relevant risk level details in HS-10/1 to HS-10/121: in the Department of Education Manual.

1.1.3.5

RISK CONTROL

The control of injury and disease risks must be addressed by the following steps: (a) (b)

designing out (or designing in) to eliminate the hazard at source; substitution (replacing with less hazardous chemical); 14

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(c) (d) (e) (f)

redesign (containing hazard by enclosure or isolation); separation (removing the person from the hazard); administration (reducing the person’s exposure to hazard); and the use of personal protective equipment.

Teachers of science should refer to the relevant risk control details in modules HS-10/1 to HS-10/121 in the Department of Education Manual.

1.1.4

IMPLICATIONS

The Duty of Care has implications for the teacher in the following situations: (a) (b) (c) (d) (e) (f)

(g) (h) (i)

the supervision of students undertaking practical work both during the teaching of science at school and in the field; the performance of demonstrations in front of students; allowing students to assist with class demonstrations; students involved in extracurricular science-related activities; sending students on errands to other parts of the school to bring back chemicals or equipment; transport of chemicals, biological materials (including animals), glassware or equipment within laboratories or around the school by teachers, scientific assistants, other school personnel or students; preventing, as far as possible, unauthorised access to hazardous materials; the formulation, publication and enforcement of laboratory rules; and maintenance of up-to-date safety procedures.

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2.

SCIENCE MANAGEMENT PROCESSES

2.1

SAFETY IN SCIENCE EDUCATION

2.1.1

INTRODUCTION

Work practices in every industry and every occupatio n today are controlled by the Workplace Health and Safety Act 1995, other Government legislation and related regulations. Safety at work is a very high priority in today's workforce and this degree of importance needs to be reflected in the management of equipment and chemicals, organisation of preparation rooms and laboratories and the demonstration of safety in learning/teaching experiences. Safety in science education involves more than just not exposing students to unnecessary risks. Teachers have a responsibility to develop a safety consciousness in students, as well as displaying appropriate safe behaviours. Safety in science education includes: (a) (b) (c) (d) (e) (f)

2.1.2

the provision of a safe working environment for staff and students; the adoption of safe working practices and other measures to minimise the risks associated with hazards encountered in a science laboratory; an awareness of the need to behave safely; knowledge of hazards in the laboratory and at home; skills to handle hazardous chemicals, equipment and situations; and an appropriate attitude towards safety and safe practices.

TEACHER'S ROLE

To achieve the above goals, teachers must: (a) (b) (c) (d) (e) (f)

have developed their own safety consciousness; be aware of the implications of behaving in an unsafe manner; have knowledge of hazards likely to be encountered; have the skills to demonstrate safe handling techniques; know what action to take in an emergency; and display the attitudes and behaviours they wish to encourage.

While it is the responsibility of the teacher to take the necessary action when an emergency arises, it is desirable that students be aware of the procedures to be adopted should the need arise.

2.1.3

REDUCING THE RISKS

Risks in science activities can be reduced by: (a) (b) (c) (d) (e) (f)

understanding; preparation; organisation; safe supervision; experimental practices; and personal protection. 16

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Understanding An example of understanding can be shown with toxic chemicals. Toxic chemicals can only be harmful if they are allowed to enter the body. Chemicals may enter the body by inhalation, absorption and ingestion. Preparation The following points should be considered when planning any science activity: (a) (b) (c) (d) (e) (f) (g) (h) (i)

class size; experience of the class; laboratory space available; number of student groups desirable; number of sets of equipment available; previous experience of the same, or similar, experimental procedures; hazards associated with the equipment or chemicals being used; prior demonstration of appropriate safe handling techniques; and emergency procedures.

Organisation The risk level of an activity can be reduced by appropriate organisation of: (a) (b) (c)

the area for the teaching of science, e.g. laboratory, classroom, or outside location; materials used for the activity; and location and movement of people involved in the activity.

The following examples indicate how organisation contributes to lowering the risk level of a science activity. (i)

Equipment and chemicals should be stored in a systematic, orderly and neat manner. The scheme adopted for storing materials should be known to all school personnel who need access to science materials. (Refer to Section 3.1.5, Storage of chemicals, for specific instructions.) (ii) In schools with many teachers, systems must be established for the distribution and return of equipment and chemicals. All equipment borrowed from a preparation room, store room, or storage area must be returned to its assigned place. (iii) Teaching areas, preparation rooms and laboratories should be kept uncluttered with no equipment protruding over benches or wires dangling or trailing across the floor. (iv) Movement around the area for the teaching of science, laboratory or preparation room should not be obstructed by furniture or equipment stored on the floor. (v) Benchtops should be kept clean. Any spillages should be wiped up immediately. (vi) Reagent bottles or dropping bottles used by students should be clearly labelled and filled regularly so that there is no need for any group to ‘borrow’ any reagent from another group because its bottle is empty. Unnecessary and frequent movement of students in a laboratory can lead to accidents. (vii) Sinks should not be allowed to become blocked with wastes of any kind. Separate waste bins should be provided for broken glass, paper, cloth etc. and solid chemical residues which are to be discarded (see Section 3.1.7, Disposal of chemicals). Broken glass must be wrapped before disposal. (viii) All water outlets should be in good working order. (ix) Gas turrets on the benches should be kept in good working order. Loose turrets, or taps with parts missing, should be reported to the local Supervisor, Department of Public Works and Housing. 17

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(x)

Bunsen burners may be left attached to gas turrets, if considered desirable. Gas tubing should be no longer than 600mm, and a 300mm square sheet of AC sheet (non-asbestos fibro) can be placed under the bunsen burner to minimise the heating effect on the benchtop. (xi) Power outlets and swit ches must be kept in safe working order. Checks should be made to ensure that cover plates on switches and outlets do not become broken or cracked, accidentally or otherwise. (xii) Time must be allowed for cleaning up and returning equipment and chemicals. Supervision Student behaviour during the teaching of science needs to be considered when assessing risk levels. Increased teacher supervision is needed for higher risk level activities. Increased teacher supervision is likely to reduce risk levels. Supervision of students may vary depending on their age and their experience of the particular activity. In practical situations, supervision needs to be continuous and vigilant so that unauthorised/inappropriate behaviour does not lead to accidents resulting in physical injury, fires or other conditions dangerous to the health and safety of others involved in the activity. A list of student rules should be drawn up, setting out the behaviour expected. Infringements of these rules should not be permitted. Rules that outline general principles are useful but not explicit and are thereby incomplete. Lists of ‘Do's and Don'ts’ should be prominently displayed and copies may be given to students. Such a list of rules for safety in science activities might include at least the following: (a) (b) (c) (d) (e) (f) (g) (h) (i)

(j) (k)

(l)

Long hair must be confined by hair nets or tied back if it is likely to be a fire hazard or come in contact with chemicals or equipment in use. Ties should be tucked in. Loose, flowing clothing must be confined, where it constitutes a hazard. Synthetic garments (e.g. nylon parkas), should be recognised as potential fire hazards. Rings, earrings, metal bands and other loose jewellery must be removed if they present a safety hazard. Footwear must completely cover the feet and protect them from spilt corrosive or hot liquids. Teachers should be aware of students who wear contact lenses. Students must wear safety goggles when chemicals are being handled. Protective clothing (gloves, aprons, eyewear) must be worn whenever the hazard dictates. Students should not be permitted to enter any laboratory unless a teacher is present. To ensure that such a situation does not arise, laboratory doors should be locked when the laboratory is not occupied. This is the responsibility of all teachers of science. Students must not be permitted to enter a preparation room or store room unless a teacher is present. Practical classes should be conducted only by teachers with the appropriate knowledge and/or experience. Should a teacher be called away from a practical class or demonstration, the students must not be left unsupervised. If a teacher is not available to supervise the class, then students should be required to leave the laboratory and some other arrangement should be made for their supervision. Unauthorised experiments by students must not be permitted.

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Experimental practices Teachers of science undertaking experimental procedures should: (a)

(b)

(c)

minimise or eliminate direct contact between the skin and chemicals that can be absorbed or cause irritation through the use of mechanical devices and protective garments, e.g. pipette fillers and gloves; reduce the risk of inhalation of chemical vapours by isolating the experiment in a fume cupboard or by using small quantities of chemicals and ensuring good ventilation in the room; and prevent students from tasting chemicals.

Students should have the manipulative skills to successfully and safely complete a particular science activity. Some of the science activities that may require a practical demonstration by the teacher include: (i) (ii) (iii) (iv) (v) (vi) (vii) (viii)

lighting and use of a bunsen burner; heating of liquids or solids in test tubes; heating large volumes of liquids; handling glassware containing hot liquids; carrying glassware; handling of reagent bottles; diluting concentrated acids; and inserting glass tubing in rubber stoppers.

Correct labelling The use of the correct labels e.g. toxic, poisonous, irritant, etc., can assist in developin g good practice and in maintaining a safe environment. (See Section 3.3 for further details.)

2.1.4

ACCIDENT PROCEDURE

Refer to HS-08: Accident and/or Incidents  Reporting and Investigation in the Department of Education Manual.

2.1.5

FIRST AID

Refer to HS-14: Health and Safety  First Aid for Schools and Non-school Locations in the Department of Education Manual. First aid procedures specific to the teaching of science can be located within the relevant section of this manual, e.g. electric shocks and electric burns (Section 4  Electrical Hazards).

2.2

FIRE

2.2.1

NATURE OF FIRES

Fires in school areas for the teaching of science may arise from any of the following causes: (a) (b) (c) (d)

chemical reactions; electrical faults; gas leakages; and poor laboratory procedures.

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The speed with which the fire can spread will depend on the nature of the burning substances and the materials in the immediate vicinity of the fire. Fires of solids propagate slowly. Fires of liquids spread relatively rapidly. Gas, vapour or dust fires propagate so rapidly that they seem to explode.

2.2.2

PREVENTION OF FIRES

Sources of ignition Possible sources of ignition and appropriate control measures which should be considered when determining risk levels and fire management are listed below. (a)

(b) (c) (d) (e) (f) (g) (h)

Matches should be completely extinguished after use and placed in a non-flammable container, not thrown into a waste receptacle which may contain paper or other flammable materials. A variety of friction or piezoelectric lighters can be used instead of matches in some circumstances. Bunsen burner flames may be nearly invisible in strong light. If there is a need to leave the burners alight when not in use, the flame should be made visible by closing the air hole. Apparatus used during heating should be allowed to cool before storage. Hot objects should not be placed directly on benchtops, paper or other flammable substances. A cool gauze mat should be used. If infra-red driers are to be used on a wooden bench, the bench should be protected by a layer of heat-insulating material. Hot plates, radiators and similar sources of high heat should not normally be operated unattended or overnight. Sodium and phosphorus should not be left exposed to air. All paper, hair and flammable clothing should be kept away from flames during experiments.

Gas installations (where fitted) (a) All personnel involved in science activities must know the position of the isolating valve for the room and the isolating valve at the bottled gas cylinders or gas meter. (b) Gas fittings on the benches and hoses connecting bunsen burners to gas turrets should be regularly inspected to ensure leak-free connections. (c) Students must be instructed to not tamper with any gas fittings. Flammable substances Flammability is a function of the ease with which a solid, liquid, vapour or gas will ignite easily and burn rapidly. There are a number of factors which are used to measure flammability such as ignition temperature and flashpoint. The following are descriptions of various degrees of flammability: highly flammable flammable combustible

These substances have a very low boiling point, form vapours easily at room temperature and are easily ignited. These substances have a higher boiling point, form vapours less easily and require a higher temperature for ignition. These substances do not form vapours easily at room temperature and require a much higher temperature for ignition.

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Flammable liquids No sources of ignition should be used near flammable liquids. Some common flammable liquids are listed below. Low flashpoint substances (ignite very easily: may form an explosive vapour−air mixture) acetone (nail polish remover) carbon disulfide cyclohexane diethyl ether ethanol ethyl acetate n-hexane methanol (methyl alcohol) methylethyl ketone petroleum ether (spirit) propan-1-ol isopropyl alcohol toluene methylated spirits (methyl alcohol)

High flashpoint substances

iso amyl alcohol 1 - butanol 2 - butanol t - butanol formalin

Flammable gases (a) All sources of ignition should be extinguished when handling flammable gases. If ignition tests of gases are being demonstrated, use only small quantities. The source of gas should be closed off or well removed from the demonstration. (b) If the combustion of substances in an oxygen-rich environment is being demonstrated, only small quantities should be used and all participants should be prepared for the substance to flare and burn rapidly. (c) Many propellant gases in pressure cans are flammable. (d) Some fluorescent lights, electrical switches and transmitting devices (radios and mobile telephones) may be sources of ignition. Combustible solids (a) Most combustible solids will not present a great fire hazard unless they are ground into a powder. Powders of combustible solids can be explosive when dispersed in air. Metals in a finely divided form, e.g. zinc dust, may ignite easily. (b) Unstable solids may decompose explosively if heated or subjected to friction. These include: • potassium chlorate; • sodium nitrate; • potassium nitrate; and • powdered metal and sulfur. (c) Strong oxidising agents must be kept away from organic substances as the combination may lead to spontaneous ignition. (d) Some solids will react spontaneously and exothermally with water or air. These include lithium, sodium, potassium, calcium, hydrides, nitrides, sulfides, acid anhydrides and concentrated acids and alkalis. Use only small quantities. Small narrow-necked containers should never be used. Appropriate procedures to avoid contact with these substances and their products should be followed. 21

ASPECTS OF S CIENCE M ANAGEMENT

Electrical fires (a) The electrical wiring in science laboratories and other activity areas should be adequately protected against overloading by circuit breakers. Repairs should be done only by a qualified electrician. (b) Wiring should not be overloaded by using appliances or equipment whose current rating is greater than that of the power outlet. General purpose outlets (GPOs) were usually rated at 10 amps. Some GPOs may be rated at 15 amps. (c) The use of double adapters should be avoided. Portable power boards (multiple -point power boards), especially those with circuit breakers, should be used. (d) All power leads must be in good condition, of the appropriate current rating for the appliance(s) being used, and of the minimum length necessary for practical use. Some teaching of science area practices (a) Appropriate storage, handling and disposal procedures for chemicals should be followed as indicated in Section 3: Chemical management. (b) Good ventilation should be maintained in laboratories and science activity preparation rooms to minimise the chances of flammable vapours or gases building up. (c) Procedures which release flammable vapours would normally be carried out in a fume cupboard or an appropriate outdoor location. (d) Large quantities of flammable liquids should not be stored in the laboratory. Bulk quantities should be stored in a preparation room or appropriate store room. (e) Flammable liquids should not be stored or used near sources of ignition. (f) Flammable liquids should only be heated on water baths using electrical hotplates, not bunsen burners. (g) Apparatus to be used in heating must be carefully checked for defects, such as small cracks or uneven thickness. (h) All fires and hazardous occurrences must be reported in the appropriate manner.

2.2.3

ACTION IN CASE OF FIRE

Equipment The location and mode of operation of fire extinguishers, fire blankets and sand buckets must be known by all participants in any science activity. Safety equipment in general, and fire extinguishers in particular, should be checked frequently to make sure they are in working condition. They should be checked for leakage, tampering and expiration of use-by dates. If a person's clothes have caught fire, lie the person down, ‘roll them over’ and smother the flames with the fire blanket. Seek urgent medical attention for any burns. Dry chemical fire extinguishers can be used on all types of fires. Follow the manufacturer’s instructions. Evacuation If a fire should break out in an area for the teaching of science, the students must be moved from the source of the fire and evacuated, if necessary. A whole school evacuation may be necessary. Observe the school’s evacuation procedures, including contact with the fire brigade.

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2.3

POISONS IN ALL CASES, CONTACT A DOCTOR OR POISONS INFORMATION CENTRE BRISBANE METROPOLITAN 3243 8233 CALLERS OUTSIDE BRISBANE (008) 177 333

2.3.1

INTRODUCTION

Speed of treatment is essential. In all cases, the Material Safety Data Sheet (MSDS) for the substance should be consulted for the first aid information in the first instance. In any case of poisoning, the nearest Poisons Information Centre or doctor should be contacted. The MSDS for the substance should accompany the person to the treating agency. Contact details must be displayed in appropriate locations. While immediate first aid is being administered, transport (either ambulance or private car) to appropriate medical facilities should also be organised. The poison should be identified and/or the container collected and/or the vomitus collected and provided for the doctor. Ensure that the patient’s airway is clear. An unconscious patient should never receive any solids or liquids by mouth. Medical aid, a doctor or a hospital should be sought as quickly as possible. The patient should be kept warm and quiet.

2.3.2

TOXICITY

Definition of terms TOXICITY

Toxicity is the capacity of a substance to cause harm. All substances should be considered as toxic to some degree. The toxicity of a substance is determined by the quantity of that substance required to cause harm. It is usually reported as an LD 50 oral rate, i.e. the lethal dose that will kill 50% of a sample -rate population if administered orally. The following values are approximate indicators for ingestion: very toxic: LD50 ≤ 25 mg/kg body weight; toxic: 25 < LD50 ≤ 200 mg/kg; harmful: 200 < LD50 ≤ 2000 mg/kg.

CORROSIVE

The risks of injury associated with any particular chemical relate directly to the route of entry, i.e. ingestion, inhalation or skin contact. A substance that may be very toxic by ingestion may be quite safe to handle if it is not to be ingested. Corrosive substances are those which cause severe skin damage. How corrosive a substance is depends on the length of time taken for the damage to occur. The following are approximate indicators of corrosiveness: highly corrosive: causes visible severe skin damage at site of contact in less than 3 minutes; 23

ASPECTS OF S CIENCE M ANAGEMENT

corrosive:

causes visible severe skin damage at site of contact in a period of 3 to 60 minutes;

24

ASPECTS OF S CIENCE M ANAGEMENT

irritating:

HYGROSCOPIC DELIQUESCENT

causes visible severe skin damage at site of contact in a period of up to 4 hours. Splashes to the eyes present a far greater risk of severe injury than splashes to skin due to the nature of the tissues in contact with the chemicals. Hygroscopic substances absorb water from the air. Deliquescent substances are hygroscopic substances that absorb water to such an extent that they form a concentrated solution of the substance.

Both hygroscopic and deliquescent substances may absorb moisture from tissue and, consequently, should be treated as potentially highly corrosive.

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2.3.3

TOXICITY AND FIRE HAZARDS ASSOCIATED WITH CERTAIN ACID ANION COMPOUNDS Compounds

Toxicity, fire hazard

Bromides

The inorganic bromides produce depression, emaciation and in severe cases psychoses and mental deterioration. Organic bromides are volatile liquids of relatively high toxicity. When strongly heated, alone or with strong acids such as concentrated sulfuric acid, they emit highly toxic fumes.

Chlorates

The principal toxic effect of chlorates is the destruction of the red blood cells, leading to kidney irritation. They constitute a dangerous fire hazard in contact with flammable materials so solid chlorates should never be placed in rubbish bins. They are powerful oxidising agents and when contaminated with oxidisable material, they are particularly sensitive to friction, heat and shock. When mixed with combustible material, they can form explosive mixtures. The reaction with concentrated sulfuric acid can be violent. The preparation of oxygen using potassium chlorate and manganese dioxide as a catalyst may cause an explosion.

Chlorides

Toxicity varies widely. When heated strongly, alone or with concentrated sulfuric acid, they can emit highly toxic fumes.

Chromates, dichromates

These compounds have a corrosive action on skin and mucous membranes. Because they are strong oxidising agents, they could cause fire by a chemical reaction. Hexavalent chromium compounds are known to be carcinogenic.

Ferricyanides

Ferricyanides as such are of low toxicity since the CN is bound. However, when they are strongly heated or come in contact with acids or acid fumes, highly toxic fumes are liberated.

Ferrocyanides

Ferrocyanides as such are of low order of toxicity, but highly toxic decomposition products can form on mixing them with hot concentrated acids. When strongly heated they emit highly toxic fumes.

Hypochlorites

These compounds are corrosive. When heated or on contact with acids or acid fumes, they emit highly toxic fumes. They form a moderate fire hazard by chemical reaction with reducing agents and organic matter.

Iodates

Toxicity is variable, producing effects similar to those produced by chlorates. They are a dangerous fire hazard because they are powerful oxidisers. In contact with flammable or even combustible materials they can start fires.

Iodides

Similar in toxicity to bromides. When strongly heated they emit highly toxic fumes.

Nitrates

Large amounts taken by mouth may have serious or even fatal effects. Practically all nitrates are powerful oxidising agents and, as such, constitute a moderate fire hazard by chemical reaction. Nitrates may explode when exposed to heat or flame or by spontaneous chemical reaction. Ammonium nitrate has all the properties of the other nitrates but is also able to detonate by itself. On strong heating, nitrates emit toxic fumes.

Oxalates

Oxalates are corrosive and produce local irritation. When taken by mouth they have a caustic effect on the mouth, oesophagus and stomach. The soluble oxalates are readily absorbed from the gastro-intestinal tract and can cause severe damage to the kidneys. When strongly heated they emit toxic fumes.

Permanganates

Highly toxic compounds with irritant properties. They are strong oxidising agents and constitute a moderate fire hazard when reacting with reducing materials. Metallic permanganate may detonate when exposed to high temperatures or shock. The reaction with concentrated sulfuric acid can be violent.

26

ASPECTS OF S CIENCE M ANAGEMENT Compounds

Toxicity, fire hazard

Peroxides

Toxicity of these compounds is variable. They may cause injury on contact with skin or mucous membranes. They represent a moderate to dangerous fire hazard by chemical reaction with reducing agents and contaminants. They are strong oxidising agents. Contact with water may cause violent decomposition.

Phosphates

Variable toxicity. When strongly heated they can emit highly toxic fumes.

Sulfates

Variable toxicity. In general, the toxic quality of substances containing the sulfate radical is that of the material with which this radical is combined. On strong heating, emits highly toxic fumes.

Sulfides

Variable toxicity. The sulfides of potassium, calcium, ammonium and sodium are similar in action to the alkalis. They cause softening and irritation of the skin. If taken by mouth they are corrosive. Sulfides of the heavy metals are generally insoluble and hence have little toxic action except through the liberation of hydrogen sulfide. They constit ute a moderate fire hazard when exposed to flame or by spontaneous chemical reaction. Many sulfides ignite easily in air at room temperature. Others require a higher temperature or the presence of an oxidiser. Many powerful oxidisers on contact with sulfides ignite violently.

Sulfites

Fairly large doses of sulfites can be tolerated since they are rapidly oxidised to sulfates, although if swallowed they may cause irritation of the stomach by liberating sulfurous acid. When heated strongly or on contact wit h acids they emit highly toxic fumes.

Thiocyanates

Severe toxicity will occur with doses of less than 1g. When strongly heated or on contact with acids or acid fumes, they emit highly toxic fumes.

Thiosulfates

Most of the thiosulfates have low toxicity. When heated strongly, they emit highly toxic fumes.

2.3.4

SKIN CONTAMINATION

Skin contamination  except phenolics The following sequence of procedures should be observed for skin contamination by substances other than phenolics: (a) (b) (c)

Remove contaminated clothing and simultaneously irrigate thoroughly the affected area with water. Continue drenching for 5 minutes and then wash gently with a little soap and a lot of water. Irrigate again with water and cover the affected area with gauze or lint.

Skin contamination — phenolics The following sequence of procedures should be observed for skin contamination by phenolic substances: (a) (b) (c)

2.3.5

Swab off the phenol using swabs soaked in glycerine or vegetable oil. Discard each swab and continue with a new swab. Care must be taken to avoid spreading the burn.

GAS OR VAPOUR INHALATION

The following sequence of procedures should be observed for the inhalation of a poisonous substance, e.g. a gas: (a)

Carry or drag the patient into fresh air. Loosen clothing, check breathing, pulse and pupils of the eyes.

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ASPECTS OF S CIENCE M ANAGEMENT

(b) (c) (d)

(e) (f)

2.3.6

If the patient is not breathing, pulse is absent and eyes are dilated, start expired air resuscitation (EAR)/cardio-pulmonary resuscitation (CPR). If patient is not breathing, but pulse is present, start expired air resuscitation (EAR). If patient is breathing but unconscious, place patient flat on the floor, roll him/her onto right side, remove dentures and clean mouth of mucus and vomitus. Keep the patient’s chin well up and forward by pushing on the angle of the jaw. Keep the patient warm. Do not give anything by mouth to the unconscious patient. If conscious, encourage the patient to take a series of rapid and deep breaths, then gradually bring him/her into a sitting position. Make certain he/she does not get up and walk around. Make patient lie flat if he/she feels faint.

CHEMICALS SWALLOWED

The following sequence of procedures should be observed after ingestion of a poisonous substance. Treatment for an unconscious patient (a) Do not give anything by mouth. (b) Place patient flat on back and then roll him/her onto side. (c) Put your finger in the patient’s mouth and remove dentures and any obstructions to breathing. Hold the patient’s jaw well up and forward. Check breathing. If not breathing, turn casualty on to back and apply E.A.R. Check pulse. If pulse absent, apply C.P.R. (d) Loosen clothing around neck, abdomen and chest. (e) If the patient vomits, clean out his/her mouth. (f) Arrange transport to hospital or doctor. Treatment for a conscious patient (a) If the substance swallowed can be identified as: • a strong acid; • a strong alkali or other corrosive; • a phenolic substance; • kerosene or a petroleum product; or is listed under poisons first aid list (which should be displa yed in an appropriate location−see 2.3.9) as a substance for which vomiting should not be induced, then do not induce vomiting but carry out the first aid instructions. (b) Give fluids−water or milk only if indicated in the poisons first aid list for the specific poison. Do not give more than 250mL as this may induce vomiting. If vomiting is to be induced, use syrup of ipecac. Do not give milk as this increases the risks if aspirated. (c) If advised by a doctor, or Poisons Information Centre, or if not contradicted above, induce vomiting by the appropriate dose of syrup of ipecac: 30mL  adult, 15mL  children, followed by 200mL of water. If vomiting has not occurred in 30 minutes, the ipecac syrup may be repeated once only. (d) If in doubt about the identity of the poison, do not induce vomiting. (e) Keep patient warm, comfortable and calm while waiting and being transported to hospital.

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2.3.7

TOXICITY OF CERTAIN METALS AND METAL COMPOUNDS ELEMENT

TOXICITY OF COMPOUNDS

Aluminium

Aluminium itself is not generally regarded as a poison. The toxicity of any compound will be determined by the nature of the anion with which the metal is combined.

Barium

The soluble barium salts such as the chloride and sulfide are poisonous when taken by mouth. The insoluble sulfate used in radiography is non-poisonous. The usual result of exposure to the sulfide, oxide and carbonate is irritation of the eyes, nose and throat and skin.

Boron

Boron itself is not highly toxic. However, instances of accidental poisoning have been reported due to boric acid, oral ingestion of borates and absorption of boric acid from wounds and burns.

Calcium

Generally speaking, calcium compounds should be considered toxic only when they contain a toxic component. Calcium oxide and calcium hydroxide have caustic reactions and are therefore irritating to the skin and respiratory system.

Chromium

Chromic acid and its salts have a highly corrosive action on the skin and mucous membrane. Chromate salts are recognised carcinogens.

Cobalt

The toxicity of cobalt itself and most cobalt salts is low. The toxicity of the compound will depend upon the anion with which cobalt is combined.

Copper

Copper chloride and sulfate have been reported as causing irritation of the skin and conjunctivae. Copper oxide is irritating to the eyes and upper respiratory tract. The ingestion of large amounts of copper sulfate can have fatal effects.

Lead

Lead poisoning may occur: (a) by inhalation of dusts, fumes, mists or vapours; (b) by ingestion of lead compounds introduced into the mouth on food, tobacco, fingers etc.; and (c) through the skin, particularly in the case of organic lead compounds. Lead is a cumulative poison. Increasing amounts build up in the body and eventually a point is reached where symptoms and disability occur. Of the various compounds, the carbonate, the monoxide and the sulfate are considered to be more toxic than metallic lead or other lead compounds.

Magnesium

Poisoning can result from prolonged exposure to fumes or dusts.

Mercury

A number of mercury compounds can cause skin irritation and can be absorbed through the skin leading to mercury poisoning. Mercury compounds and the metal itself may enter the body as vapours of fumes or dusts. Some can cause kidney damage while others can cause irreversible damage to the central nervous system. Mercuric compounds are generally more toxic than mercurous compounds.

Nickel

Nickel and most salts of nickel are generally not considered toxic. Nickel (II) compounds are carcinogenic.

Potassium

Toxicity of the compounds is variable. The potassium ion is practically non-toxic; hence, the toxicity of potassium compounds would depend upon the anion involved.

Silver

The silver ion is intensely corrosive to tissue.

Sodium

Toxicity varies with the compound. The sodium ion is considered non-toxic. The toxicity of sodium compounds is frequently due, though not always, to the anion involved.

Strontium

The strontium ion has a low order of toxicity. It is chemically and biologically similar to calcium. The toxicity of the compounds is considered to be dependent upon the anion involved.

Zinc

Zinc is not inherently a toxic element. Small doses of soluble zinc salts cause nausea and vomiting. Larger doses cause violent vomiting and purging. Zinc chloride, because of its caustic action, can produce skin ulcers.

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2.3.8

HAZARDS ASSOCIATED WITH CERTAIN GASES (including cryogenic gases) Gas

Description

Hazardous procedures

Ammonia, anhydrous

Extremely irritating gas. Flammable in the presence of sufficient oxygen.

Carbon dioxide

Simple asphyxiant.

Carbon monoxide

Very toxic. Can cause unconsciousness due to combination of the gas with haemoglobin in the blood. Death can occur from carbon monoxide inhalation.

Do not prepare carbon monoxide in open room. Use fume cupboard. Reduce metallic oxides by passing carbon monoxide over the heated oxide.

Chlorine

Very toxic. Can react to cause fires or explosions upon contact with turpentine, ether, ammonia gas, illuminating gas, hydrocarbon, hydrogen and powdered metals. Dissolves readily in water, forming highly corrosive solution.

Do not prepare chlorine in open room. Use fume cupboard. Direct combination of chlorine and hydrogen in bright light or ignition of the mixture by lighted taper or electric spark. Avoid reactions of chlorine with metals, solid non-metals, hydrocarbon. Use small quantities only.

Hydrogen

Do not prepare ammonia in open room. Use fume cupboard.

Do not allow direct combination of hydrogen and chlorine in bright light or ignition of the mixture by lighted taper or electric spark. Ignite a jet of hydrogen issuing from a delivery tube. Reduce metallic oxides by passing hydrogen over the heated oxide.

Hydrogen chloride, anhydrous

Corrosive.

Do not prepare hydrogen chloride in open room. Use fume cupboard.

Hydrogen sulfide

Both an irritant and an asphyxiant.

Do not prepare hydrogen sulfide in open room. Use fume cupboard. Igniting a jet of hydrogen sulfide issuing from a delivery tube.

Liquid helium and

Colourless and odourles s liquid gas. Liquid causes rapid freezing on contact.

Only experienced and properly trained people should use this product.

Avoid contact with escaping liquid and gas. Skin may freeze to surfaces cooled by liquid and be torn on removal. Liquid can cause tissue freezing or frostbite.

Do NOT expose to skin, eye, inhale or swallow.

LP gas (bottled gas)

Simple asphyxiant. Consists of propane (approximately 95%) together with varying proportions of butane, propylene and butylene. A rank-smelling compound is added so that the presence of the gas can be easily detected. Incomplete combustion yields carbon monoxide.

Do not search for a gas leak with a lighted match or lighted taper. Use a soap solution.

Natural gas

Simple asphyxiant. Consists of methane (approximately 90%) together with varying proportions of ethane, propane, butane, nitrogen and carbon dioxide. A ranksmelling compound is added so that the presence of the gas can be easily detected.

Do not search for a gas leak with a lighted match or lighted taper. Use a soap solution.

liquid nitrogen

Obtain specialist advice before operating cryogenic liquid equipment.

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ASPECTS OF S CIENCE M ANAGEMENT Gas

Description

Hazardous procedures

Incomplete combustion yields carbon monoxide.

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ASPECTS OF S CIENCE M ANAGEMENT

2.3.9

ALPHABETICAL LIST OF POISONS AND FIRST AID

The relevant sections of the MSDS for the substance should be consulted in the first instance. S UBSTANCE

FIRST AID IF INGESTED

Acetamide

Give 120-240mL milk or water.

Acetic acid glacial

Do not induce vomiting. Give 120-240mL water or milk.

Acetone

If swallowed, do NOT induce vomiting. Give glass of water. Contact doctor.

Aceto-orcein stain

Do not induce vomiting. Give water or milk.

Acridine

Give water. Induce vomiting.

Adrenaline

Give water.

Aluminium chloride

Give milk or water.

Aluminium nitrate

Give water. Induce vomiting.

Aluminium oxide

Give 120-240mL milk or water.

Ammonia concentrated

Do not induce vomiting. Give 120-240mL milk or water. Contact doctor.

Ammonium dichromate

Do not induce vomiting. Give 120-240mL milk or water.

Ammonium metavanadate

Give 120-240mL milk or water.

Ammonium molybdate

Give 120-240mL milk or water.

Ammonium oxalate

Give milk or water. Give calcium as milk, weak lime water, chalk solution to precipitate oxalate.

Ammonium persulfate

Give 120-240mL milk or water. Do not induce vomiting

Ammonium thiocyanate

Give water. Induce vomiting using Ipecac Syrup APF. Contact doctor.

Iso-amyl alcohol

Give water. Induce vomiting if patient is not drowsy.

Aniline sulfate

Give water. Induce vomiting.

Barium compounds

Give water, give magnesium sulfate (50mg/kg for children to a maximum dose of 30g (adult)).

Benedict's solution

Do not induce vomiting. Give 120-240mL milk or water.

Bial's reagent (orcinol in concentrated hydrochloric acid)

Do not induce vomiting. Give 120-240mL milk or water.

Boric acid

Give water. Induce vomiting.

Bromine liquid

Give milk or water. Do not induce vomiting.

Buffer solution tablets pH2

Give milk or water. Give calcium as milk, weak lime water or chalk to precipitate oxalate.

pH4-10

Do not induce vomiting. Give 120-240mL milk or water.

Butanol primary, secondary and tertiary

Give water. Induce vomiting if patient is not drowsy.

Calcium acetate monohydrate

Give milk or water. Do not induce vomiting.

Calcium hydroxide

Give milk or water. Do not induce vomiting.

Calcium metal

Remove any adhering metal and penetrating particles and drench skin with water except when contact has been slight. Rinse mouth thoroughly with water. Give plenty of water.

Calcium oxide

Do not induce vomiting. Give 120-240mL milk or water.

Camphor

Do not induce vomiting. Give 120-240mL milk or water.

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ASPECTS OF S CIENCE M ANAGEMENT S UBSTANCE

FIRST AID IF INGESTED

Carbon disulfide

Give water. Induce vomiting. Contact doctor.

Carbon tetrachloride (not allowed in Queensland schools)

Give water. Induce vomiting if > 15 minutes from a hospital, may cause seizures. Exercise extreme caution. Contact doctor.

Chloroform

Give water. Induce vomiting if > 15 minutes from a hospital. Contact doctor.

Chrome alum

Induce vomiting if > 15 minutes from a hospital. Give milk or water.

Chromic acetate

Give 1 g vitamin C, then 120-240mL water or milk.

Chromic sulfate

Induce vomiting if > 15 minutes from a hospital. Give water or milk.

Chromic trioxide

Induce vomiting if > 15 minutes from a hospital. Give 1 g Vitamin C, then water or milk.

Copper chloride

Give water. Induce vomiting.

Chromic nitrate

Induce vomiting if > 15 minutes from a hospital. Give milk or water.

Copper sulfate

Give water. Induce vomiting if > 15 minutes from a hospital.

Cyclohexane

Do not induce vomiting. Give 120-240mL water or milk. Contact doctor.

Delafield's haematoxylin solution

Give water. Induce vomiting.

Di-n-butyl phthalate

Give 120-240mL water or milk.

Para dichlorobenzene

Give water. Induce vomiting. Avoid giving milk or oils .

Dichloromethane

Do NOT induce vomiting..

Dichlorophenolindophenol sodium

For DCPIP tablets give water. Induce vomiting.

Diethyl ether

Give water. Induce vomiting.

DPX mounting medium

Do not induce vomiting. Give 120-240mL water or milk.

Ethanol absolute

Give water. Induce vomiting if patient is not drowsy.

Ethyl acetate

Give water. Induce vomiting.

Ethylene glycol

Induce vomiting if > 15 minutes from a hospital.

Euparal

Do not induce vomiting. Give 120-240mL water or milk.

Formalin 40%

Immediately administer milk or water, bread or any protein with which formaldehyde can interact. Induce vomiting.

Formic acid

Give 120-240mL milk or water. Do not induce vomiting.

n-hexane

Give 120-240mL milk or water. Do not induce vomiting.

Hydrochloric acid

Do not induce vomiting. Give 120-240mL water or milk.

Hydrogen peroxide

Do not induce vomiting. Give plenty of water or milk. Contact doctor ASAP.

Iodine

Give milk or water. Then give milk, starch, or bread to oxidise iodine to iodide. Induce vomiting if > 15 minutes from a hospital.

Kerosene

Do not induce vomiting. Give 120-240mL water or milk.

Lead and lead compounds

Give water. Induce vomiting if > 15 minutes from a hospital.

Leishman’s stain

Give water. Induce vomiting if patient is not drowsy.

Lithium chloride

Induce vomiting.

Lithium hydroxide

Do not induce vomiting. Give 120-240mL water or milk.

Lithium nitrate

Give water. Induce vomiting.

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ASPECTS OF S CIENCE M ANAGEMENT S UBSTANCE

FIRST AID IF INGESTED

Maleic acid

Do not induce vomiting. Give 120-240mL water or milk.

Manganese compounds

Give water. Do not induce vomiting.

Mercuric chloride

Give water. Induce vomiting if > 5 minutes from hospital. Give raw egg. Contact doctor.

Mercury and mercury compounds

Give water. Induce vomiting if > 15 minutes from a hospital.

Methanol

Give water. Induce vomiting if > 15 minutes from a hospital.

Methylated spirits

Give water. Induce vomiting if > 15 minutes from a hospital.

Methyl ethyl ketone

Give water. Do not induce vomiting.

Millon’s reagent

Give water. Induce vomiting.

I-naphthol (alpha)

Do not induce vomiting.

Nickel sulfate

Induce vomiting.

Nitric acid

Do not induce vomiting. Give 120-240mL water or milk.

Octanol

Give water. Induce vomiting if patient is not drowsy.

Oxalic acid

Give milk or water. Give calcium as milk, weak lime water, chalk to precipitate oxalate. Do NOT induce vomiting.

Pentanol

Give water. Induce vomiting if patient is not drowsy.

Perchloric acid

Do not induce vomiting. Give 120-240mL water or milk.

Pentan-1-ol

Give water. Induce vomiting if patient is not drowsy.

Petroleum ether

Do not induce vomiting. Give 120-240mL water or milk.

Phenyl thiourea

Give water. Induce vomiting if > 15 minutes from a hospital..

Phloroglucin

Give milk or water. (Give 30-60mL of castor oil.)

Phosphorus pentoxide

Do not induce vomiting. Give 120-240mL water or milk.

Phosphorus white

Give water. Do not induce vomiting.

Potassium carbonate anhydrous

Do not induce vomiting. Give 120-240mL water or milk.

Potassium chromate

Give milk or water. Give 1g Vitamin C.

Potassium dichromate

Give milk or water. Give 1g vitamin C.

Potassium hydrogen oxalate

Give water. Give calcium as milk, weak lime water, chalk to precipitate oxalate.

Potassium hydroxide

Do not induce vomiting. Give 120-240mL water or milk.

Potassium iodide

Give water. Induce vomiting.

Potassium nitrate

Give water. Induce vomiting.

Potassium permanganate

Do not induce vomiting. Give 120-240mL water or milk.

Potassium thiocyanate

Give water. Induce vomiting.

Propanol

Give water. Induce vomiting if patient is not drowsy.

Isopropyl alcohol

Give water. Induce vomiting if patient is not drowsy.

Pyrogallol

Give milk or water. (Give 30-60mL of castor oil.)

Quinine sulfate

Give water. Induce vomiting.

Resorcinol

Give milk or water. (Give 30-60mL of castor oil.)

34

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FIRST AID IF INGESTED

Sebacoyl chloride

Give water. Induce vomiting.

Silver salts

Give milk or water. Do not induce vomiting.

Soda lime

Do not induce vomiting. Give 120-240mL water or milk.

Sodium carbonate

Do not induce vomiting. Give 120-240mL water or milk.

Sodium chromate

Do not induce vomiting. Give 120-240mL water or milk.

Sodium dichromate

Do not induce vomiting. Give 120-240mL water or milk.

Sodium dihydrogen orthophosphate

Induce vomiting. Give water.

Sodium hydroxide

Do not induce vomiting. Give 120-240mL water or milk.

Sodium hypochlorite

Do not induce vomiting. Give 120-240mL water or milk.

Sodium iodide

Give water. Induce vomiting.

Sodium metabisulfite

Do not induce vomiting. Give 120-240mL milk or water.

Sodium metal

Remove any adhering metal and penetrating particles and drench skin with water except where contact has been slight. Rinse mouth thoroughly with water. Give water.

Sodium oxalate

Give milk or water. Give calcium as milk, weak lime water, chalk to precipitate oxalate.

Sodium peroxide

Do not induce vomiting. Give 120-240mL water or milk.

Sodium phosphate

Do not induce vomiting. Give 120-240mL water or milk.

Sodium sulfide

Give water. Do NOT induce vomiting.

Sulfuric acid

Do not induce vomiting. Give 120-240mL water or milk.

Sodium persulfate

Give 120-240mL milk or water. Do not induce vomiting.

Sodium tartrate

Give 120-240mL milk or water.

Sucrose

Nil.

Toluene

Do not induce vomiting. Give 120-240mL water or milk.

Trace element mixture

Give water. Induce vomiting.

Turpentine (mineral)

Do not induce vomiting. Give 120-240mL water or milk. Contact doctor immediately.

Turpentine (vegetable)

D o not induce vomiting. Give 120-240mL water or milk.

Xanthydrol

Give water. Induce vomiting if patient is not drowsy.

35

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2.4

EQUIPMENT

2.4.1

GAS INSTALLATIONS AND INSPECTIONS

Portable gas bottles (9kg or less) The school is responsible for maintaining and filling these cylinders, and for having them tested after they are ten years old. It is illegal for a refilling station to refill cylinders older than 10 years that have not been retested. Permanent gas installations These include laboratories supplied with large 45kg cylinders of LPG or connected to natural or town gas. Sales and Distribution Services (SDS), formerly Q. P. & S. and Edmart, arrange for contracts for ‘refillers’ and servicing of installations. All permanent installations should be serviced annually. In this service, turrets, control valves and cylinders are checked for correct operation and leaks. The age of cylinders is also checked. If they are found to be out of date, the contractor will check with the school for the date of the last refill. If the cylinders have not been refilled for some time, the school will be asked to organise a refill whether the cylinders are empty or not. Cylinders may be refilled on site or replaced. It is the refiller’s responsibility to check the date on your cylinder and provide ones that are current. The Regional Manager of Department of Public Works and Housing can advise which company has the contract to refill a school's gas cylinders. Isolation valves All gas should be turned off when not in use. Areas for the teaching of science with permanent gas are fitted with isolation valves. These may be manual or electronic. New science facilities are being provided with electronic key-pad controlled isolation valves. All personnel, whether involved in a practical activity or not, who are using rooms equipped with reticulated gas supply should familiarise themselves with the various methods of isolating gas when not in use.

2.4.2

ELECTRICAL OUTLETS AND EQUIPMENT

Electrical outlets Permanent general purpose electrical outlets must be in a safe and operational condition. New installations must be fitted with automatic blind outlets. For further information regarding electrical safety refer to Section 4. Commercial electrical equipment The Regulatory Unit of the Department of Minerals and Energy (DME) (formerly the Queensland Electricity Commission [QEC], now called the Queensland Electricity Industry [QEI] has set down stringent guidelines for equipment operating on 240 volts (V). Teachers are reminded that home-made 240V equipment would be unlikely to comply with legal specifications. All 240V electrical equipment should be serviced and checked by a qualified electrician. Equipment suppliers must supply schools with equipment that complies with QEI specifications, including appropriate earthing and use of approved insulating materials.

36

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2.4.3

EYE WASHING AND SAFETY SHOWER

Eye washing Doors in and around preparation rooms are usually locked for security reasons. However, to enable access to safety shower and eye washing facilities, teachers should ensure that connecting doors to preparation rooms are unlocked and open at the beginning of practical classes. The first 10-30 seconds are critical in the treatment of chemical splashes in the eye. The minimum recommended time for continuation of eye washing is 20 minutes. Contact lenses should be removed. For permanent eye washing fixtures, the water stream should allow continual irrigation of the eye without harmful pressure being placed on it. Where eyewash bottles are used, appropriate squeezing of the bottle will irrigate the eye for a short period. A continuous supply of water may still be needed after the eyewash bottle has been emptied. Eyewash bottles should be regularly emptied and re-filled to prevent algal and micro-organism contamination of their contents. The correct wearing of appropriate eye protection such as goggles, will significantly lessen the possibility of eye injury. Safety shower Where safety showers are installed, the person affected by a chemical spill should stand in the appropriate place and be thoroughly doused. Where safety showers are not installed, the nearest tap/hose should be employed. Permanent eye washing and safety shower facilities should be checked periodically. Water pressure should be sufficient and appropriate.

2.4.4

FUME CUPBOARDS

Fume cupboards provide a means of isolating hazardous gases and vapours from the classroom and dispersing them into the atmosphere. Fume cupboard doors must be able to be locked to prevent access to preparation and storage rooms from the teaching of science area. Fume cupboards should not be used for long-term storage of any chemicals or as distribution areas for class sets of chemicals and equipment. There are several types of fume cupboards with different methods of dispersal to the atmosphere. These are: Mechanical Most modern fume cupboards have an extraction fan mounted in the flue that creates sufficient draft to exhaust gases and vapours to the atmosphere. These need to be serviced periodically to remove any phys ical obstructions (e.g. birds' nests) and check on corrosion of the electric motor or fan. Heat-induced convection These older-style units have a gas burner mounted permanently at the entrance to the flue. When alight the hot gases cause a rising convection current which draws the hazardous gas or vapour through the flue. These units pose a significant fire hazard when flammable gases or liquids are placed in the fume cupboard when the burner is alight. Do not attempt to use the burner in these fume cupboards. 37

ASPECTS OF S CIENCE M ANAGEMENT

Diffusion A fume cupboard may have a simple flue which allows dispersal of gases and vapours by molecular diffusion. This type of unit cannot be used to disperse gases that are heavier than air. They will accumulate in the bottom of the unit and slowly leak back into the classroom. These units are not acceptable for use in gas dispersion. Australian Standards, AS 2243.8 Fume Cupboards and AS 2243.9 Recirculating Fume Cupboards, detail certain testing and maintenance that must be carried out by a competent person on fume cupboards at 6– and 12–monthly intervals.

2.4.5

WATER STILLS

A potential hazard exists if stills do not have an automatic power supply cut-off in case of failure of the water supply. If the water supply fails, the unit may overheat and cause a fire. Most models produced in the last 10 years have automatic cut-off switches fitted. These should be periodically checked. Normally, stills should not be operated overnight or left unattended for long periods during the day.

2.4.6

PENETRATING OBJECTS  CARBON DIOXIDE SYPHON BULBS

The practice of using CO2 (carbon dioxide) soda syphon bulbs in a number of activities, particularly in the demonstration and explanation of the principles of rocketry, has resulted in a number of serious accidents to people and property over past years. The use of these items, particularly in primary schools, is strongly discouraged.

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3. CHEMICAL MANAGEMENT 3.1

ORGANISATION

3.1.1

INTRODUCTION

All aspects of packaging, labelling, recording, storing, handling and disposing of chemicals are governed by the following codes: (a) (b) (c) (d) (e)

the National Code of Practice to Control Workplace Hazardous Substances; the Australian Code for the Transport of Dangerous Goods; the Workplace Health and Safety Act and Regulations; and the Poisons Regulations of 1973; and the Sewerage and Water Supply Act 1949-1982.

The information contained here is in accordance with the regulations of the above codes and complies with recommendations of the Hazardous Waste Unit of the Division of Environment and Occupational Health, Queensland Government Department of Health and the Government Chemical Laboratory. School personnel can refer to the information provided to ascertain the specific hazard associated with particular substances, the appropriate handling procedures, and the necessary action required in case of spills. The first source of reference, however, should be Material Safety Data Sheets (MSDS).

3.1.2

PREVENTION OF PERSONAL INJURY

The risk of injury from hazardous chemicals is very low, provided the chemicals are not allowed to enter the body or come in contact with skin. All school personnel involved in the teaching of science have a responsibility to be aware of the specific hazards associated with chemicals used in school laboratories and to use appropriate handling procedures. The following points are aimed at reducing the possibility of chemicals entering the body. Ventilation

Ventilation of classrooms and especially preparation rooms must be adequate. Preparation rooms should not be used as staff rooms for teachers or scientific assistants.

Personal hygiene

Personal hygiene is essential in avoiding chemical hazards. Hands should be thoroughly washed at the conclusion of each practical period. Cuts and scratches should be covered to prevent entry of chemicals or pathogens. Pens or pencils must not be sucked or labels licked. Food and drink should not be allowed in areas for the teaching of science or preparation rooms.

Appropriate protective clothing

Appropriate protective clothing should be worn if there is a possibility of being splashed by hazardous chemicals.

Types of protective clothing: • For the hands: Protection can be achieved by the use of gloves and creams which act as a barrier. Gloves are designed for specific purposes and should not be used in situations for which they are not designed. 39

ASPECTS OF S CIENCE M ANAGEMENT

The three kinds of gloves are: (1) (2) (3)

disposable surgical gloves, which are used during dissections, handling animal tissue and blood products, but not for chemicals; rubber washing-up gloves, which are not designed to protect against concentrated chemicals or organic solvents (e.g. acetone); and nitrile chemical−resistant gloves, which are designed for handling concentrated acids and organic solvents.

All are available from Sales and Distribution Service (SDS). Gloves may be rendered useless if punctured or contaminated by careless removal or replacement. This could lead to increased exposure of the skin to chemicals. Unless specifically directed, most chemicals used in schools can be handled safely without gloves, provided splashes on unprotected skin are washed off immediately. • For the eyes: Protection is required in all situations where there is a possibility of splashing from hazardous chemicals, hot liquids or particles such as chemical granules or glass fragments. The eye protection worn must comply with Australian Standard AS 1337 for protection against chemical splashes. • For the body: Protection includes the use of aprons or laboratory coats. A heavy-duty vinyl apron should be used for handling highly corrosive substances. Lighter-duty aprons and cotton laboratory coats should be used for dissections and when handling less corrosive materials. • For the feet: Covered footwear must be worn to ensure both the upper foot and underside of the foot is protected. Accidental spillage can be minimised by: • handling and carrying chemicals correctly, e.g. by using acid carriers for transporting concentrated or bulk chemicals; • using appropriate equipment, e.g. solvents and other liquids should not be pipetted by mouth but by a pipette bulb; • organising and managing the activity and the work area of students to minimise movement in the teaching of science area; and • using correct laboratory procedures.

3.1.3

CHEMICALS USED IN SCHOOLS FOR THE TEACHING OF SCIENCE

All substances used in the teaching of science should be regarded as being potentially hazardous, but some substances have particular physical and chemical properties that make them more hazardous than other substances. Consult the Departme nt of Education Manual activity module Health and Safety HS-10/51: Management and Storage of Hazardous Science Substances. Teachers must be aware of the hazards associated with the chemicals they use, the appropriate action to take in the case of spills and the correct method of disposal. This information is not conveyed by the label alone. Additional information should be obtained from the Regional Occupational Health and Safety Adviser, Material Safety Data Sheets (MSDS) or other technical references. 40

ASPECTS OF S CIENCE M ANAGEMENT

If schools currently hold stocks of chemicals that are not on the direct delivery list, they should contact the distributor, manufacturer or the Regional Occupational Health and Safety Adviser to obtain hazard, spill and disposal procedures for those substances.

3.1.4

CHEMICAL STOCKS

Normally, no more than three years’ supply of chemicals (at current rate of usage) should be held in stock. Chemical companies have indicated that many chemicals used in schools have a shelf life of approximately three years or less once opened. A chemical of biological origin might have quite a limited shelf-life. Refer to labels for shelf-life information, and order and consume stock accordingly. If labels have corroded and are illegible, use an outside agency to dispose of the chemical. Chemicals which are no longer used because textbooks have changed and/or certain experiments are no longer conducted should be discarded. CHEMICALS PROHIBITED FOR SCHOOL USE N.B.: In previous years, government schools have been directed not to use a number of chemicals. These have been potassium chlorate in the preparation of oxygen with manganese dioxide as a catalyst (potentially explosive), benzene and carbon tetrachloride (both of which are highly carcinogenic). These prohibitions remain. A number of other substances pose potentially major risks and schools should consider very carefully whether the curriculum relevance of experiments and demonstrations involving these substances is sufficient to warrant their being stocked. In such cases, minimum quantities should be obtained, stored and used. Such substances include: • mercury (Mercury might be required for some senior chemistry and physics experiments/demonstrations (e.g. manometers/barometers), and mercury thermometers might be necessary for senior classes, but generally the use of mercury should be limited. Primary and lower secondary students can use alcohol thermometers or digital devices in most circumstances); • mercuric salts and the salts of other heavy metals; • very strong oxidising agents; • very strong reducing agents; • very strong caustic/corrosive agents; and • very toxic substances. Should any of these prohibited substances still exist in schools, then schools should dispose of them according to the guidelines in 3.1.7.

3.1.5 3.1.5.1 (a)

STORAGE OF CHEMICALS General handling and storage precautions All chemicals must be stored in cool, dry, well-ventilated store rooms away from direct sunlight. Flammable chemicals should not be stored in cupboards in stair -wells used as exits

41

ASPECTS OF S CIENCE M ANAGEMENT

(b)

(c) (d) (e) (f) (g)

(h)

or near other ‘traffic areas’ because they might explode or release poisonous gases during a fire. Shelving must be strong enough to bear the weight of materials stored; deep enough to allow safe placement without the risk of containers being accidentally dropped; appropriately spaced so that labels are readily seen and containers can be reached safely; and of sufficient number to prevent overcrowding of containers. Usually, shelving would be of solid wood (not particleboard), with chemicals arranged in alphabetical order. All containers should be marked with their date of receipt at the school. Containers of chemicals should be rotated on the shelves so that old stocks are used first. Metal containers and/or metal lids should be avoided as they can corrode over time. Chemicals, especially solvents, should not be stored above eye level. This avoids the possibility of spilling chemicals while removing them from the shelves. Concentrated acids and alkalis should be stored at floor level and standing in a tray large enough to contain a substantial spill. Some schools have a specially made lead-lined trough to accommodate all acids, alkalis and solvents. Others use a tray that is lead-lined or a plastic tote box. Flammable liquids must be stored well away from sources of heat. Fireproof cupboards are desired specifically for the safe containment of flammable liquids. Highly flammable liquids may be stored in refrigerators provided the refrigerators have been modified to prevent internal sparking.

Safety is a key word when handling chemicals. A. Some basic handling procedures (a) (b) (c)

(d) (e) (f) (g)

All reagent bottles should be properly sealed and they should be picked up by the body of the bottle. When removing a glass stopper, twist it as the lifting force is applied, holding the base firmly to the table. When pouring liquids, ensure that the label is at the top. This prevents the destruction of the label by the excess liquid that often moves across the lower outside surface of the bottle. It also minimises skin contact with any leakage on that side of the bottle. The exterior of a reagent bottle should be cleaned of spilt liquid after use. All reagent bottles must be clearly labelled. Solid reagents should be taken from the container with a spatula, tongs or other suitable device. Shaking of materials from bottles usually results in wastage. Screw tops should be tightened to prevent the free access of air, as some reagents will react with oxygen and/or water vapour and/or carbon dioxide in the air. Some tops have the added security of self-adhesive plastic tape around the cap. This should be replaced after use if damaged, and after its adhesive property has diminished.

B. General safety rules for chemicals (a)

(b) (c)

Never touch a chemical; gloves should be worn especially when handling bottles of poisonous or corrosive chemicals; goggles should be worn when heating chemicals or whenever there is danger of ‘spitting’, as, for example, when making a dilute solution of sulfuric acid. Never directly inhale over an opened container. Instead, fan some of the vapour with the hand towards the nose. Volatile liquids should always be handled in the fume cupboard, taking care not to expose the skin to the vapour. Many volatile liquids are extremely flammable and should not be uncorked near an exposed flame. 42

ASPECTS OF S CIENCE M ANAGEMENT

(d) (e) (f) (g) (h) (i) (j) (k)

Always handle chemicals with tools. Never allow the skin to come into direct contact, as some materials are absorbed through the skin. Wash your hands after handling chemicals and when leaving the laboratory. Never leave unlabelled chemicals in any position. Partially completed experiments should be labelled. When pouring liquids from a bottle hold the bottle by its side to avoid the danger of burns from skin contact with chemicals. Never look down over a container to observe a reaction, as spitting may occur. If possible, always add the more reactive material to the less active material. Do not eat food in the laboratory or preparation room. Be familiar with the position and contents of the first aid kit, and the procedures to follow in case of accident.

C. Reactive combinations requiring special precautions Some reactive combinations requiring special care or complete avoidance have been outlined below. A comprehensive list of incompatible chemical combinations can be found in Section 3.1.5.3, in Incompatible substances. Also keep in mind that reactions are generally more vigorous when the materials are finely divided. (a)

(b)

(c) (d)

(e) (f) (g)

Carbonates, nitrites, sulfides and sulfites react vigorously with acids, producing gases such as carbon dioxide, oxides of nitrogen, hydrogen sulfide, and sulfur dioxide. Because of the poisonous nature of such gases any such reactions should, in general, be carried out in a fume cupboard. Although carbon dioxide, in the quantities that usually are prepared, is not dangerous, the reaction between powdered carbonates and acids is often extremely vigorous. Concentrated sulfuric acid and concentrated or dilute nitric acid react vigorously with metals to produce poisonous sulfur dioxide and oxides of nitrogen respectively. Such reactions must be performed in a fume cupboard. Concentrated sulfuric acid mixed with chlorides, bromides or iodides produces poisonous irritating gases. Such reactions should be carried out in a fume cupboard. Potassium, sodium, lithium, calcium, lithium hydride, the oxides of sodium, potassium or calcium (quicklime), the chlorides of phosphorus and calcium carbide with water should be avoided. Potassium, sodium, lithium, calcium, magnesium powder, aluminium powder with acids should be avoided. Powdered aluminium or powdered zinc with alkalis should be avoided. Oxidising and reducing agents ground together in a mortar should be avoided.

D. Safe storage of chemicals Some of the points listed below will be reiterated in a later section pertaining to science facilities and equipment. Some crucial general points to be noted are: (a) (b)

All dangerous or poisonous chemicals and materials must be stored in locked cupboards in preparation rooms, or in locked store rooms. In general it is unwise to keep chemicals in laboratory display cupboards or on side benches except for the following purposes: (i) (ii)

occasional displays of types of chemicals; or current experimental use.

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For the latter, reagents should be placed on racks which can be removed or locked away after a lesson. Check also with the Head of Department on the special problems associated with handling such chemicals. (c)

Here are a few ‘Don’ts’ (i) (ii) (iii)

Do not store flammable chemicals in cupboards above benches where heating devices such as bunsen burners are used. Store flammables below bench level. Do not use any flammable chemicals on a bench on which a heating device such as a bunsen is being used. Do not store oxidising agents near ‘oxidisables’ (i.e. reducing agents), and be careful to choose a cool place to store oxidising agents. Oxidising agents  hydrogen peroxide; nitric acid, sulfuric acid, lead IV oxide (peroxide); lead II, III, IV oxide (red lead), manganese IV oxide (dioxide), any chlorates, chromates, dichromates, iodates, nitrates; permanganates (manganate VII), iodine, bromine, cylinders of oxygen or chlorine. Oxidisables (reducing agents)  carbon; carbon compounds such as wood, paper, cotton, sugars, starch, and any organic solvents, e.g. alcohols; metals, nitrites; phosphorus; sulfur, sulfites, thiosulfates; chlorides, bromides, iodides.

(iv)

Do not stand bottles of concentrated acid on wood shelving. Store bottles of concentrated acids on lead-lined shelves at floor level. If lead-lined shelves are not available, store bottles of concentrated acids at floor level, preferably on sheet lead. Do not store metals near acids. • Do not store ammonia bottles near hydrochloric acid bottles as gases from these interact. • Do not store iodine bottles with other chemicals unless the iodine bottles are placed inside a larger sealed jar, as iodine vapour is very corrosive of metal lids and metal fittings. • Do not store methanal (formalin) solutions in the same cupboard as hydrochloric acid as the vapours of the two solutions interact to form a carcinogen.

3.1.5.2

Storage of chemicals in plastic containers

All companies supplying chemicals to schools must comply with national regulations, including specified packaging and labelling. Approximately 90% of solid chemicals are packed in plastic. All 500mL liquid chemicals and pack sizes smaller than 500mL are in glass, except hydrogen peroxide, which is supplied in a special plastic pack. All 2.5L liquid chemicals would normally be supplied in glass, except hydrochloric acid, which is packed in plastic. Plastic containers are designed to be completely compatible with the chemicals they contain for at least 3 to 5 years provided they are stored in cool, dry places away from direct sunlight. Chemicals stored for more than 3 years in plastic should have their containers checked for brittleness. Given the life expectancy of plastic containers and the fact that many chemicals, once opened, have a guaranteed shelf life of approximately 2 to 3 years, chemicals should not remain on the shelves for longer than 3 years.

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3.1.5.3

Special handling and storage precautions

Concentrated acids These should be stored at floor level and in containers standing in lead-lined troughs or trays or plastic tote boxes sufficient to contain an accidental spill. Acids frequently used in schools include: Acetic Hydrochloric Nitric Perchloric Sulfuric

    

store away from inorganic acids (H2SO4, HCl); keep away from formalin; see Incompatible substances; see Incompatible substances; see Incompatible substances.

Flammable liquids These should be stored well stoppered, at or below eye level, and in a well-ventilated area away from sources of heat. Flammable liquids frequently used in schools include acetone, cyclohexane and cyclohexene, Delafield's haematoxylin solution, diethyl ether, ethanol, ethyl acetate, methanol, methylated spirits, methyl ethyl ketone, petroleum ether, iso-propyl alcohol and xandthydrol (contains methanol). Other solvents or liquids Other solvents or liquids frequently used in schools include: Ammonia (conc.) Carbon disulfide Chloroform Formalin Sodium hydroxide (conc.)

keep away from oxidising agents, store as for acids but separate; as for ammonia; keep very well sealed and in a well-ventilated area; store in glass, tightly stoppered and taped, away from hydrochloric acid; store as for acids but separate. Use only cork, rubber or plastic stoppers, not glass.

Powerful oxidising agents Powerful oxidising agents should be stored away from other chemicals, especially organics. These may include ammonium dichromate, ammonium nitrate, hydrogen peroxide (can be kept in the refrigerator), nitric acid (see acids), perchloric acid (see acids), potassium chromate, potassium dichromate, potassium iodate, potassium nitrate, potassium permanganate, silver nitrate, sodium chromate, sodium dichromate (should not be allowed to become damp. The addition of 10% by weight of water can cause spontaneous combustion, and contact with a moist combustible item, including clothes, may cause fire. They should be stored in a desiccator. Extra care should be taken with sodium dithionite, sodium nitrate, sodium peroxide, sulfuric acid (see acids). Consult MSDS for further details.

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Incompatible substances The following mixtures are some of the chemical combinations which can be dangerous, either at room temperature or when heated. Do not allow contact between Group A and Group B substances except under the specific conditions outlined in the following table. Group A

Group B

Alkali metals —Ca, K, Na

H 2O, CO2, halogenated hydrocarbons, mercury, acids (use pieces of metal less than half peasize when reacting Na with H2O).

Acetic acid

Chromic acid, nitric acid, perchloric acid, peroxides, perchlorates and permanganates.

Aluminium dust

Oxides or oxidising agents, chlorinated hydrocarbons, sulfur, alcohols, silver nitrate.

Aluminium chloride

Water.

Acetone

Concentrated sulfuric acid and nitric acid mixtures and oxidising agents.

Acetylene

Cop per (tubing), fluorine, bromine, chlorine, iodine, silver, mercury or their compounds.

Ammonia, anhydrous

Mercury, halogens, calcium hypochlorite, hydrogen fluoride, perchloric acid and silver. Unused ammoniacal silver nitrate solutions should not be allowed to stand. The silver should be precipitated with NaCl. Do not put ammoniacal silver nitrate in with silver residues.

Ammonium nitrate

Acids, metal powders, flammable liquids, chlorates, nitrates, sulfur and finely divided organic substances or combustible substances.

Aniline

Nitric acid, hydrogen peroxide, hydrochloric acid, sulfuric acid.

Bromine

Ammonia, acetylene, butane, hydrogen, turpentine, and finely divided metals, acetone, ether, ethanol.

Chlorates

Ammonia, ammonium salts, acids, metal powders, sulfur, finely divided organics or combustibles, carbon.

Chromic acid

Acetic acid, naphthalene, camphor, alcohols, glycerine, turpentine and other flammable liquids, organic substances and sulfur, finely divided metals.

Chromium trioxide

Organic solvents, i.e. acetone etc.

Chlorine

Ammonia, acetylene, petroleum fractions, hydrogen, turpentine and finely divided metal or powders.

Hydrogen peroxide

Copper, chromium, iron, most metals and their respective salts, flammable liquids and other combustible materials, aniline, acids.

Hydrocarbons, general

Fluorine, chlorine, bromine, chromic acid, peroxides.

Iodine

Acetylene, ammonia.

Mercury

Acetylene, fulminic acid, hydrogen, sodium, oxalic or tartaric acid.

Nitric acid

Acetic acid, chromic acid and hydrocyanic acid, aniline, carbon, hydrogen sulfide, flammable substances or substances already nitrated, organic substances.

Oxygen

Oils, greases, hydrogen, flammable liquids, solids and gases. (Grease should be kept away from cylinders of oxygen and their fittings.) If it is desired to demonstrate the burning of hydrogen at the end of the delivery tube from a flask of acid and zinc, protect the whole apparatus with a wire gauze or plastic safety screen.

Oxides and strong

Magnesium or aluminium powders, finely divided organic substances, flour, sugar, powdered

46

ASPECTS OF S CIENCE M ANAGEMENT Group A

Group B

oxidising agents

milk.

Oxalic acid

Silver or mercury.

Perchloric acid

Acetic anhydride, bismuth and its alloys, alcohol, paper, wood and other organic materials, oils, greases or ammonia.

Potassium permanganate

Glycerine, sulfuric acid, organic substances, metals, sulfur, phosphorus, hydrogen peroxide.

Silver

Nitric acid -ethyl alcohol mixtures. Ammoniacal silver nitrate solutions should not be allowed to stand. The silver should be precipitated with NaCl. Do not put ammoniacal silver nitrate solutions in with silver residues.

Finely divided organic substances, flour, starch, sugar, milk powders

Strong oxidising agents (use only small quantities as in reaction of sugar with concentrated acid).

Sodium peroxide

Any oxidisable substance, methanol, acetic acid, acetic anhydride, carbon disulfide, glycerine, ethyl acetate, carbon, organic substances, fine metals.

Sulfuric acid

Chlorates, perchlorates, permanganate and water.

Zinc dust

Chlorinated hydrocarbons, oxides or oxidising agents, sulfur.

Other chemicals • Carbon disulfide Carbon disulfide is an extremely dangerous chemical since it can undergo ignition in air, not only from a spark or naked flame, but also from a hot object (e.g. a tripod stand). Rooms in which carbon disulfide is being used should be well ventilated and free from naked flames and any hot objects. • Residues should not be poured into the sink, but burnt in small quantities in an open flat dish in a fume cupboard with forced ventilation. • Phosphorus (yellow/white) STUDENTS SHOULD NOT BE PERMITTED TO USE THIS CHEMICAL. Phosphorus should be stored under water, in a wide -mouth glass bottle with a glass stopper or screw lid. The bottle should be placed in an open vessel containing sand and kept well away from flammable liquids and heat-sensitive solids. If the phosphorus has been supplied in a metal tin, then it must be transferred into a glass container. Fill the container two-thirds with water; then use tongs to transfer the phosphorus with minimum exposure to air. The level of fluid in the bottle should be checked periodically. Before handling phosphorus, prepare a dilute solution of copper sulfate (30 g in a litre of water) in a shallow non-metallic dish. If yellow phosphorus touches the skin, immerse the affected part immediately and scrape off any obvious pieces of phosphorus. Cover the injury with a wet dressing and seek medical attention. When cutting: (a) Use tongs to transfer a piece of phosphorus to a dish containing about 10 cm of water. (b) Use the tongs to steady the phosphorus and cut it under water with a knife. A piece no larger than half the size of a pea should be used. (c) Do not handle with the fingers. 47

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48

ASPECTS OF S CIENCE M ANAGEMENT

When burning: (a) Because the phosphorus pentoxide gas produced when phosphorus burns in air is quite toxic, the piece of phosphorus should be transferred to a gas jar or similar container by a deflagrating spoon as soon as possible. Avoid breathing the gas and conduct the experiment in a well-ventilated area or fume cupboard. (b) Dry phosphorus ignites spontaneously when exposed to the air. • Diethyl ether Diethyl ether is an extremely dangerous chemical since it can undergo ignition in air, not only from a spark or naked flame, but also from a hot object (e.g. a tripod stand). Diethyl ether, in contact with air or direct sunlight for an extended period of time can form peroxides which are unstable and can explode due to friction. For this reason, diethyl ether should be stored in an amber glass bottle away from direct sunlight and should be disposed of after three years. • Sodium Sodium should be stored under kerosene or paraffin oil, in a wide -mouthed glass bottle with a glass stopper or screw lid. The bottle should be placed in an open vessel containing sand and kept well away from flammable liquids and heat-sensitive solids. If the sodium has been supplied in a metal tin then it must be transferred into a glass container. Fill the container two-thirds with kerosene; then use tongs to transfer the sodium with minimum exposure to air. The level of fluid in the bottle should be checked periodically. If sodium falls on the skin, remove the metal quickly and flood the area with water for several minutes. Seek medical attention. In the event of a fire from sodium, cover the sodium with dry sand, remove it on a spade to waste ground and ignite it or allow it to react completely with water. Sodium tarnishes on exposure to air and reacts violently with water and water vapour. When cutting: (a) Use tongs to transfer a piece of sodium to a dish containing about 3 cm of kerosene. (b) Use the tongs to steady the sodium and cut it under kerosene with a knife. A piece no larger than half the size of a pea should be used. (c) Do not handle with the fingers. When demonstrating the reaction between sodium and water, students should be at least one metre away from the container in which the reaction is to take place or a very small piece of sodium (match-head size) may be placed in a 1 L beaker which can be covered with a gauze mat. • Mercury Mercury must not be heated. Occupational poisoning by mercury and its inorganic compounds is usually of the chronic type, and the vapour of metallic mercury is the most common source of exposure. Mercury gains access to the body mainly through the respiratory tract. The volatility of mercury, which vaporises at room temperature, and the tendency of spilled mercury to form innumerable small droplets are properties which contribute to the difficulty of avoiding dangerous exposure. The effects of continuous exposure to small concentrations of mercury vapour or inorganic mercury salts are tremor of the hands, insomnia, irritability and depression; in other words, a change of temperament is noticeable. Organic mercury compounds, especially those

49

ASPECTS OF S CIENCE M ANAGEMENT

which exist as liquids and dusts, may also be absorbed as vapour and dust through the lungs, with much the same symptoms as above. In addition, organic mercurial dusts have an irritating effect on the skin and cause blistering. Spillages should be cleaned up as quickly as possible. Procedures for cleaning could include: (a) (b) (c) (d) (e)

collect droplets of mercury with a small pipette fitted with a rubber pipette filler; discard to a waste bottle; cover the area with lime-sulfur or sulfur powder and leave for 24 hours; sweep the area thoroughly, collect the waste lime and mercury and discard to a designated waste bottle; and the area should be washed and scrubbed.

A tray (not aluminium) should be used under apparatus containing mercury in the event of a spill. Mercury surfaces should not be left exposed to the air and any transference from one container to another should be done in a fume cupboard.

3.1.6 3.1.6.1 (a) (b) (c) (d)

(e) (f)

CHEMICAL SPILLS PROCEDURE General procedures Personal injury must be treated first. If the spill is likely to cause injury to students, evacuation should occur. If spills involve solvents or other chemicals that give off toxic fumes, pay particular attention to the ventilation of the area and possible sources of ignition. Spillages of a small scale should be simply wiped or swept and in most cases washed to waste with running water. However, it would be worth checking the appropriate method of disposal in Table 2. For spillages of a larger scale, refer to Table 2 for specific information. In all cases, the spill area should be thoroughly washed with water and dried, as far as possible. If the spill involves an oily substance, soapy solutions will be required to reduce the risk of a slippery surface.

3.1.7

DISPOSAL OF CHEMICALS

3.1.7.1

General principles

The disposal of chemicals should only be performed by teachers who are aware of the chemical constituents to be disposed of and who are capable of carrying out the correct method of disposal. Otherwise, guidance should be sought from appropriately qualified people. Acids/alkalis Small quantities of dilute acids and alkalis can be disposed of by washing to waste with running water. Flammable liquids Flammable liquids that are immiscible (do not mix) with water should not be disposed of down the sink. Large amounts can be disposed of by burning in small quantities in a shallow tray in an open area or by evaporation in open areas or fume cupboards with forced ventilation.

50

ASPECTS OF S CIENCE M ANAGEMENT

Solids It is best to keep waste paper and rags separate from solid wastes. Place them in different containers. Some solid residues (e.g. sodium peroxide, chlorates etc.) could, on drying, set fire to paper and rags. Never put solids down the sink. Collect solid wastes in a suitable container and label. Small quantities of solid wastes can be disposed of in normal refuse. Be careful about putting different solids in the same container. Two substances which by themselves are harmless may become very reactive when in contact with each other  refer to the section on Incompatible substances Section 3.1.5.3 If solutions of heavy metal salts from practical work have been collected, then wastes should be evaporated to near-dryness in the fume cupboard and the remaining sediment stored for disposal when storage becomes a problem. Unwanted chemicals Over time, some schools may have accumulated an excess of some chemicals (e.g. phosphorus), from years of over-ordering or over-supply. Also, some chemicals are no longer used in existing courses. Schools should store only those chemicals that are required for current courses. Quantities held should not exceed 2 or 3 years’ requirements. The major chemical companies have indicated that many chemicals have a shelf life of 2 to 3 years once opened and that plastic containers will not be guaranteed past 5 years. Consult MSDS for further details.

3.1.7.2

Methods of disposal Schools should dispose of excess chemicals no longer required. Refer to the following tables for the method of disposal. Every attempt should be made to dispose of as much as possible locally. Consult MSDS for further information. Table 1: Method of disposal codes outlines a number of disposal procedures which are identified by an alphabetic code that needs to be read in conjunction with Table 2: Disposal information, which lists chemicals, their required disposal method, and other classification requirements such as class, risk and United Nations Number.

Table 1: Method of disposal codes Code

Method of disposal

A

Dilute with a large volume of water by adding acid to water, neutralise with sodium carbonate and wash to waste with running water.

B

Dilute, neutralise with dilute hydrochloric acid and wash to waste with running water.

C

Add a little at a time to a large quantity of water to dissolve. Wash to waste with running water.

D

Wash to waste with running water in sink.

E

Dissolve in water, add excess saturated sodium sulfate solution and allow to stand. Wash filtrate to waste with running water. Precipitate may be discarded in normal refuse.

F

Add to dilute strong alkali solution and discard to waste with running water. This should be done in a fume cupboard.

G

Wear eye protection. In a fume cupboard, add small amounts at a time to water in a trough or basin and leave until the reaction is complete. Wash to waste with running water.

51

ASPECTS OF S CIENCE M ANAGEMENT

Code

Method of disposal leave until the reaction is complete. Wash to waste with running water.

H

Place on a shallow tray in the fume cupboard and allow to evaporate with forced ventilation.

I

Dissolve in water, add excess calcium chloride solution and allow to stand. Wash the filtrate to waste with running water. Precipitate may be discarded in normal refuse.

J

Outside agency, e.g. Government Chemical Laboratory (GCL) or private chemical disposal company.

K

Dispose with normal refuse. (Be considerate of cleaners and deposit discarded bottles and chemicals in the industrial bin. Bottles of chemicals should not be left for cleaners.)

Table 2: Disposal information Code

Shipping name

Disposal method

Class

Sub Risk

UN No.

Pk Group

20001

ACETAMIDE

D

20005

ACETIC ACID, GLACIAL

A

8

2798

II

20010

ACETONE

H

3.1

1090

II

20015

ACETO-ORCEIN STAIN

K

20041

ADIPOYL CHLORIDE

J

8

1760

III

20045

AGAR POWDER

K

20050

ALIZARIN YELLOW

K

20055

ALUM, POTASH

K

20060

ALUMINIUM CHLORIDE, HYDRATED

K

20070

ALUMINIUM NITRATE, HYDRATED

K

5.1

1438

III

20072

ALUMINIUM OXIDE

K

20075

ALUMINIUM SULFATE, HYDRATED

K

20080

AMMONIA, CONCENTRATED

B

20085

AMMONIUM CARBONATE

C

20090

AMMONIUM CHLORIDE

C

20095

AMMONIUM DICHROMATE

J

5.1

1439

II

20096

AMMONIUM DI HYDROGEN PHOSPHATE

K

20097

di AMMONIUM HYDROGEN PHOSPHATE

K

20098

AMMONIUM METAVANADATE

J

6.1

2859

II

20099

AMMONIUM MOLYBDATE

J

20100

AMMONIUM NITRATE

D

5.1

1942

III

20105

AMMONIUM OXALATE

I

6.1

2449

III

52

ASPECTS OF S CIENCE M ANAGEMENT Code

Shipping name

Disposal method

Class

Sub Risk

UN No.

Pk Group

5.1

1444

III

20106

AMMONIUM PERSULFATE

C

20107

AMMONIUM PHOSPHATE, TRIBASIC

K

20110

AMMONIUM SULFATE

C

20115

AMMONIUM THIOCYANATE

J

20120

iso AMYL ALCOHOL

H

3.2

1105

III

20125

ANILINE HYDROCHLORIDE

J

6.1

1548

III

20130

ANILINE SULFATE

J

6.1

2811

20133

ASCORBIC ACID

A

20135

BARIUM CHLORIDE, HYDRATED

E

6.1

1564

III

20140

BARIUM HYDROXIDE, HYDRATED

E

6.1

1564

III

20145

BARIUM NITRATE

E

5.1

6.1

1446

II

20147

BEEF EXTRACT

D

20150

BENEDICT'S SOLUTION

C

20161

BORIC ACID

A

20165

BROMINE, LIQUID

F

8

6.1

1744

I

20170

BROMOTHYMOL BLUE

K

20180

BUFFER SOLUTION TABLETS, pH 4

K

20185

BUFFER SOLUTION TABLETS, pH 6.4

K

20190

BUFFER SOLUTION TABLETS, pH 8

K

20195

BUFFER SOLUTION TABLETS, pH 9.2

K

20200

1-BUTANOL

H

3.2

1120

II

20205

2-BUTANOL

H

3.2

1120

II

20210

t-BUTANOL

H

3.2

1120

II

20215

CALCIUM ACETATE MONOHYDRATE

K

20220

CALCIUM CARBONATE, MARBLE CHIPS

K

20225

CALCIUM CARBONATE, PRECIPITATED

K

20228

CALCIUM CHLORIDE, DRIED (1.5-2.5mm)

D

20230

CALCIUM CHLORIDE, DIHYDRATE

D

20235

CALCIUM CHLORIDE, FUSED

D

20240

CALCIUM HYDROXIDE, POWDER

B

20250

CALCIUM METAL, GRANULES

G

53

ASPECTS OF S CIENCE M ANAGEMENT Code

Shipping name

Disposal method

Class

Sub Risk

UN No.

Pk Group

20255

CALCIUM NITRATE, HYDRATED

D

5.1

1454

III

20260

CALCIUM, OXIDE POWDER

C

8

1759

III

20265

CALCIUM SULFATE, HYDRATED

K

20272

CAMPHOR

K

4.1

2717

III

20275

CARBON DISULFIDE

H

3.1

1131

I

20300

CHLOROFORM

H

6.1

1888

II

20305

CHROMATOGRAPHY PAPER

K

20306

CHROME ALUM

J

20310

CHROMIC ACETATE, HYDRATED

J

20315

CHROMIC SULFATE, HYDRATED

J

20316

CHROMIC NITRATE, HYDRATED

J

5.1

2720

III

20317

CHROMIUM TRIOXIDE

J

5.1

1463

II

20320

CITRIC ACID, MONOHYDRATE

A

20325

COBALT (II) CHLORIDE, HYDRATED

D

20330

COBALT (II) NITRATE, HYDRATED

D

5.1

1477

II

20332

CONGO RED

K

20335

COPPER CARBONATE

K

20340

COPPER FOIL

K

20341

COPPER (II) CHLORIDE

K

20345

COPPER (II) NITRATE, HYDRATED

K

5.1

1477

II

20350

COPPER, OXIDE

K

20355

COPPER, TURNINGS

K

20365

COPPER (II) SULFATE, HYDRATED

K

20370

COPPER (II) SULFATE, ANHYDROUS

K

20390

CRYSTAL VIOLET

K

6.1

2811

III

20400

CYCLOHEXANE

H

3.1

1145

II

20405

CYCLOHEXENE

H

3.1

2256

II

20410

DELAFIELD'S HAEMOTOXY SOLUTION

J

20415

DIALYSIS TUBING

K

20417

DIAMINOHEXANE

J

2280

III

20418

DIBUTYLPHTHALATE

K

8

6.1

8

8

54

ASPECTS OF S CIENCE M ANAGEMENT Code

Shipping name

Disposal method

Class

Sub Risk

UN No.

Pk Group

20420

PARA DICHLOROBENZENE

J

6.1

1592

III

20422

DICHLOROMETHANE

H

6.1

1593

III

20425

DIETHYL ETHER

H

3.1

1155

I

20430

DPX MOUNTING MEDIUM

K

20435

EOSIN, WATER-SOLUBLE

K

20440

ETHANOL, ABSOLUTE

D

3.1

1170

II

20445

ETHYL ACETATE

H

3.1

1173

II

20450

ETHYLENE GLYCOL (ETHANDIOL)

D

6.1

2810

III

20460

FERRIC CHLORIDE, HYDRATED

D

8

1173

III

20465

FERRIC NITRATE, HYDRATED

D

5.1

1466

III

20467

FERRIC ORTHOPHOSPHATE

K

20470

FERRIC OXIDE

K

20475

FERROUS AMMONIUM SULFATE

D

20480

FERROUS SULFATE, HYDRATED

D

20485

FERROUS SULFIDE

K

20487

FILTER PAPER

K

20490

FILTER PAPER

K

20495

FILTER PAPER

K

20497

FILTER PAPER

K

20500

FORMALIN

J

3.2

1198

III

20517

FORMIC ACID

A

8

1779

II

20520

FUMARIC ACID

K

20531

GIBBERELLIC ACID

K

20534

GLASS WOOL

K

20537

GLUCOSE

D

20540

GLYCEROL

D

20543

GRAPHITE

K

20547

n-HEXANE

H

3.1

1208

II

20549

HYDROCHLORIC ACID, CONCENTRATED

A

8

6.1

1789

II

20552

HYDROGEN PEROXIDE, 30% STABILISED

C

5.1

8

2014

II

20558

INDICATOR PAPER, pH 4-6 DISPENSER

K

6.1

55

ASPECTS OF S CIENCE M ANAGEMENT Code

Shipping name

Disposal method

Class

Sub Risk

UN No.

Pk Group

8

5.1

1759

III

1616

III

20561

INDICATOR PAPER, pH 6-8 DISPENSER

K

20564

INDICATOR PAPER, pH 1-14 DISPENSER

K

20570

INDICATOR PAPER, LITMUS, BLUE

K

20576

INDICATOR PAPER, LITMUS, RED

K

20579

INDIGO CARMINE

K

20582

IODINE, SOLID

J

20585

IRON FILINGS

K

20586

IRON WIRE

K

20591

KIESEL GEL, GRADE C

K

20592

LAURIC ACID

K

20593

LACTOSE

K

20594

LEAD ACETATE

J

6.1

20597

LEAD DIOXIDE

J

5.1

6.1

1872

II

20600

LEAD, FOIL, 0.3MM THICK

K

20603

LEAD NITRATE

J

5.1

6.1

1469

II

20606

LEAD OXIDE, LITHARGE

J

20609

LEISHMAN'S STAIN, SOLID

K

3.1

6.1

1992

II

20610

LITHIUM CHLORIDE HYDRATED

D

20611

LITHIUM NITRATE

D

5.1

2722

III

20613

LITHIUM HYDROXIDE

B

8

2680

II

20614

LITMUS, GRANULATED

K

20615

MACCONKEY'S BROTH (PURPLE, GRANULES)

K

20616

MAGNESIUM CARBONATE

K

20617

MAGNESIUM CHLORIDE

D

20618

MAGNESIUM HYDROXIDE

B

20619

MAGNESIUM NITRATE HYDRATED

D

5.1

1474

III

20621

MAGNESIUM OXIDE

K

20624

MAGNESIUM, RIBBON

K

20627

MAGNESIUM SULFATE, HYDRATED

D

20630

MALEIC ACID

K

20633

MALEIC ACID

K

56

ASPECTS OF S CIENCE M ANAGEMENT Code

Shipping name

Disposal method

Class

Sub Risk

UN No.

Pk Group

20636

MANGANESE DIOXIDE

D

20638

MANGANOUS CHLORIDE, HYDRATED

K

20639

MANGANOUS SULFATE

K

20640

MANNITOL

K

20642

MERCURIC OXIDE

J

6.1

1641

II

20645

MERCUROUS NITRATE

J

6.1

1627

II

20646

MERCURY (II) CHLORIDE

J

6.1

1624

II

20648

MERCURY, METAL

J

8

2809

III

20651

METHANOL, ABSOLUTE

J

3.1

1230

II

20652

METHYL CELLULOSE

K

20657

METHYLENE BLUE

K

20660

METHYLETHYL KETONE

H

3.1

1193

II

20663

METHYL ORANGE

K

20666

METHYL RED

K

20669

MILLON’S REAGENT

J

6.1

2024

II

20670

NAPHTHOL (ALPHA NAPHTHOL)

J

20675

NICKEL (II) CHLORIDE, HYDRATED

J

20677

NICKEL (II) SULFATE

J

20678

NITRIC ACID, CONCENTRATED

A

8

2031

II

20680

OCTAN -1-OL

K

20684

ORANGE IV (TROPAEOLIN 00)

K

20687

OXALIC ACID, HYDRATED

I

6.1

2449

III

20688

PENTAN-1-OL

C

20695

PEPSIN

K

20696

PEPTONE, BACTERIOLOGICAL

K

20699

PERCHLORIC ACID, 60% W/W

A

5.1

1873

I

20702

PETROLEUM ETHER

H

3.1

1271

II

20708

PHENOLPHTHALEIN

K

20711

PHENOL RED

K

20712

PHENYL THIOUREA

J

20714

PHLOROGLUCINOL

J

6.1

8

57

ASPECTS OF S CIENCE M ANAGEMENT Code

Shipping name

Disposal method

Class

Sub Risk

UN No.

Pk Group

1807

II

1381

I

20717

PHOSPHORUS PENTOXIDE

J

8

20723

PHOSPHORUS, WHITE

J

4.2

20724

PHOSPHOROUS, RED

J

4.1

1338

III

20735

POTASSIUM BROMIDE

D

20739

POTASSIUM CARBONATE HYDRATED

B

20741

POTASSIUM CHLORIDE

D

20744

POTASSIUM CHROMATE

J

6.1

2811

III

20747

POTASSIUM DICHROMATE, CRYSTALS

J

5.1

1479

II

20748

POTASSIUM DI HYDROGEN PHOSPHATE

K

20750

POTASSIUM FERRICYANIDE

J

20753

POTASSIUM FERROCYANIDE

J

20756

POTASSIUM HYDROGEN OXALATE

I

6.1

2449

III

20759

POTASSIUM HYDROGEN PHTHALATE

C

20762

POTASSIUM HYROGEN SULFATE

D

8

2509

II

20765

POTASSIUM HYDROGEN TARTRATE

C

20768

POTASSIUM HYDROXIDE, FLAKED

B

8

1813

II

20771

POTASSIUM IODATE

C

20744

POTASSIUM IODIDE

D

20777

di POTASSIUM MONO HYDROGEN PHOSPHATE

K

20780

POTASSIUM NITRATE

D

5.1

1486

III

20783

POTASSIUM PERMANGANATE

J

5.1

1490

II

20786

POTASSIUM THIOCYANATE

J

20787

PROPIONIC ACID

A

8

1848

III

20788

PROPAN-1-0L

D

3.1

1274

II

20789

ISO PROPYL ALCOHOL

H

3.1

1219

II

20792

QUININE SULFATE

J

20795

RESIN, ION EXCHANGE, DOWNEX AGI-X 8

K

20797

RESORCINOL

J

6.1

2876

III

20806

SAFRANIN 0

K

20807

SALICYLIC ACID

A

20809

SEBACOYL CHLORIDE

J

8

1760

II

6.1

6.1

3.2

58

ASPECTS OF S CIENCE M ANAGEMENT Code

Shipping name

Disposal method

Class

Sub Risk

UN No.

Pk Group

1346

III

1493

II

20810

SILICA GEL, OVEN BAKED

K

20813

SILICON, POWDER

K

20819

SILVER ACETATE

J

20822

SILVER CHLORIDE

J

20825

SILVER NITRATE

J

5.1

20828

SILVER, SHEET, 30 SWG STRIP

20831

SODA LIME, ACTIVATED

B

8

1907

III

20834

SODIUM ACETATE, HYDRATED

D

20836

SODIUM ALGINATE

K

20837

SODIUM BENZOATE

K

20840

SODIUM BICARBONATE

D

20843

SODIUM BROMIDE

D

20846

SODIUM CARBONATE, ANHYDROUS

B

20849

SODIUM CARBONATE, DECAHYDRAT E

B

20852

SODIUM CHLORIDE

D

20855

SODIUM CHROMATE

J

6.1

2811

III

20856

tri SODIUM CITRATE

D

20858

SODIUM DICHROMATE

J

5.1

1479

II

20859

SODIUM DITHIONITE

D

4.2

1384

II

20860

SODIUM DIHYDROGEN ORTHOPHOSPHATE HYDRATED

K

20861

di SODIUM ETHYLENE DIAMINE TETRA ACETATE Na EDTA

D

20864

SODIUM HYDROXIDE, PELLETS

B

8

1823

II

20867

SODIUM HYPOCHLORITE 12.5% SOLUTION

D

8

1791

III

20870

SODIUM IODIDE

D

20873

SODIUM METABISULFITE

C

20876

SODIUM, METAL, PELLETS, PARAFFIN

J

4.3

1428

II

20878

SODIUM, MOLYBDATE, HYDRATED

J

20879

SODIUM MONO HYDROGEN PHOSPHATE

K

20882

SODIUM NITRATE

D

5.1

1498

III

20885

SODIUM OXALATE

I

6.1

2449

III

4.1

6.1

6.1

59

ASPECTS OF S CIENCE M ANAGEMENT Code

Shipping name

Disposal method

Class

Sub Risk

UN No.

Pk Group

5.1

1504

I

8

1849

II

5.1

1505

III

5.1

1507

III

20888

SODIUM PEROXIDE

C

20891

SODIUM PHOSPHATE, TRIBASIC, HYDRATED

K

20994

SODIUM SULFATE

K

20897

SODIUM SULFIDE

K

20900

SODIUM SULFITE

K

20901

SODIUM TETRABORATE (BORAX)

K

20902

SODIUM PERSULFATE

C

20903

SODIUM THIOCYANATE

J

20904

SODIUM TARTRATE

K

20906

SODIUM THIOSULFATE, HYDRATED

D

20909

STARCH, POTATO

K

20912

STARCH, SOLUBLE

K

20917

STRONTIUM CHLORIDE

D

20918

STRONTIUM NITRATE

D

20922

SUCROSE

K

20933

SUDAN IV

K

20934

SULFANILIC ACID

J

20936

SULFUR, POWDER

K

4.1

1350

III

20939

SULFUR, ROLL

K

4.1

1350

III

20942

SULFURIC ACID, CONCENTRATED

A

8

1830

II

20946

TES-TAPE

K

20950

TIN (II) CHLORIDE HYDRATED (STANNOUS CHLORIDE)

K

20954

TIN, SHEET, 0.4mm THICK

20957

TOLUENE

H

3.1

1294

II

20958

TOLUIDINE BLUE

J

20961

TRACE ELEMENT MIXTURE

D

20967

UNIVERSAL CLEANING AGENT (DECON 90)

D

20968

UNIVERSAL INDICATOR

C

20969

UREA

K

20970

VITAMIN C TEST MATERIAL DICHLOROPHENOL/ INDOPHENOL

D

60

ASPECTS OF S CIENCE M ANAGEMENT Code

Shipping name

Disposal method

20972

XANTHYDROL, 10% W/V IN METHANOL

J

20977

YEAST, POWDER

K

20978

ZEPHIRAN

D

20979

ZINC CHLORIDE

K

20980

ZINC CARBONATE

K

20981

ZINC, FOIL STRIP

K

20984

ZINC, GRANULATED, ARSENIC-FREE

K

20987

ZINC, POWDER

K

20990

ZINC NITRATE, HYDRATED

K

20993

ZINC OXIDE

K

20996

ZINC SULFATE, HYDRATED

K

Class

Sub Risk

UN No.

Pk Group

8

2331

III

5.1

1514

II

6.1

2811

III

61

ASPECTS OF S CIENCE M ANAGEMENT

3.1.7.3

Transportation of chemicals Transport of chemicals by road and rail The following information is based on an original document compiled in conjunction with the Road Safety Division, Department of Transport (Dangerous Goods Division) and the Government Chemical Laboratory (GCL). Teachers of science and scie ntific assistants should never transport chemicals in their own vehicles. There are commercial contractors who specialise in the transportation and disposal of hazardous chemicals by road (consult your telephone directory). This document provides schools with the necessary information for disposal of excess or unwanted chemicals and, if necessary, how to return them to the Government Chemical Laboratory or to a private contractor. The transport of hazardous substances by road or rail is controlled by the Australian Code for the Transport of Dangerous Goods and its associated regulations. Schools, like all other industries, are required to comply with this Code. The requirements of the Code have been summarised, and this summary represents the absolute minimum necessary for compliance with the Code.

Read the following information carefully before consigning chemicals to the Government Chemical Laboratory or to a private contractor. Return only those chemicals that are required to be returned for disposal (i.e. indicated in the method of disposal Tables 1 and 2) or those that cannot be disposed of locally. N.B.: At the time of publication, the Government Chemical Laboratory advised that it would receive and dispose of small quantities of unwanted chemicals from both government and non-government schools. Schools are advised to make arrangements with the GCL before consigning chemicals, including checking on any costs that might subsequently be incurred. (a)

List all the chemicals to be transported.

(b)

Determine their class and subsidiary risk as indicated in Table 2. (If the chemicals to be disposed of are not in Table 2, then contact the Occupational Health and Safety Adviser for details.)

(c)

Segregate chemicals according to class. (Only chemicals of the same class group can be packed together.)

(d)

Separate those chemicals from within a group that may react with each other (e.g. acids and bases).

(e)

Check that each individual container has the correct name and hazard label. (These should be on the original label.) If the material being disposed is waste, then label it according to the type of waste  for example, lead dioxide.

(f)

Check that each container does not exceed the maximum allowable mass or volume for that particular class, as indicated in Table 3.

(g)

Check that lids are securely fastened and that containers are in a sound condition, e.g. that plastic is not brittle. (Transfer contents to more sturdy, suitable containers if necessary, and re-label.)

62

ASPECTS OF S CIENCE M ANAGEMENT

(h)

For outer packaging, choose sturdy cardboard boxes, preferably ones in which chemicals have arrived. Each carton must contain no more than 5kg or 5L of chemicals.

(i)

When packing liquids, use an unreactive packing material, e.g. vermiculite (kitty litter) or diatomaceous earth, that will absorb the liquid in the event of a spill. When packing solids, use a packing material that will not react with the chemicals if they are spilt. Packing should be placed below, around and above containers.

(j)

The outside of each carton must have a label carrying the following information: • the chemical names; • the UN No. (United Nations number) for each chemical; • the class label (one class per carton) and their subsidiary risk label, if one applies; • name and address of the consignor (the principal and school address). Advice regarding the UN No. and the class label can be obtained from your schoolbased Workplace Health and Safety representative or from the Regional Occupational, Health and Safety Adviser.

(k)

Photocopy the sample shipping document (see Table 5: Shipping documentation) and complete (even for road and rail).

(l)

Obtain Emergency Procedure Guides (EPGs) from the Standards Association of Australia (refer to Table 4).

(m)

Attach the shipping document to the EPGs and deliver to the transport company or railway.

Transport of chemicals by sea (a)

Before you deliver the package for transport, contact the Harbour Master, ship's captain or the person responsible for cargo to get approval.

(b)

The requirements for transport by road or rail are very similar to those for transport by sea. Therefore, if all the procedures in the road or rail section above have been followed, then the chemicals should be accepted as cargo.

Table 3: Maximum quantities per container Class of dangerous goods

3.1

3.2

4.1

4.2

4.3

5.1

6.1

8

Maximum quantity

150mL

300mL

2.0kg

500g

150g

1 L or 1 kg

500mL or 500g

500mL or 500g

63

ASPECTS OF S CIENCE M ANAGEMENT

Table 4: Chemicals requiring EPGs Chemical

UN No.

Class

Notes

ADIPOYL CHLORIDE

1760

8

AMMONIUM DICHROMATE

1439

5.1

ANILINE HYDROCHLORIDE

1548

6.1

CHLOROFORM

1888

6.1

CHROMIUM TRIOXIDE

1463

5.1

COPPER NITRATE

1477

5.1

DIAMINOHEXANE (HEXAMETHYLENEDIAMINE)

2280

8

PARADICHLOROBENZENE

1592

6.1

IODINE

1759

8

LEAD ACETATE

1616

6.1

LEAD DIOXIDE

1872

5.1

LEAD NITRATE

1469

5.1

MERCURIC OXIDE

1641

6.1

MERCUROUS NITRATE

1627

6.1

MERCURY METAL

2809

8

METHANOL

1230

3.1

MILLON'S REAGENT

2024

6.1

PHOSPHORUS PENTOXIDE

1807

8

PHOSPHORUS WHITE

1381

4.2

PHOSPHORUS RED (AMORPHOUS)

1338

4.1

POTASSIUM DICHROMATE

1479

5.1

RESORCINOL

2876

6.1

SILVER NITRATE

1493

5.1

SODIUM CHROMATE

2811

6.1

Use poisonous solids EPG.

SODIUM DICHROMATE

1479

5.1

Use oxidising substances EPG.

SODIUM METAL

1428

4.3

SODIUM SULFIDE

1849

8

SULFUR POWDER/ROLL

1350

4.1

Use corrosive liquid EPG.

Use corrosive solid EPG.

Use mercury compounds EPG.

Use oxidising substances EPG.

64

ASPECTS OF S CIENCE M ANAGEMENT

Table 5: Shipping documentation TO: NAME:

GOVERNMENT ANALYST

FROM:

GOVERNMENT CHEMICAL LABORATORY

NAME: ADDRESS:

ADDRESS:

Correct shipping name

KESSELS ROAD COOPERS PLAINS QLD 4108 PHONE NO: (07) 3274 9111 Class

Sub. risk

TELEPHONE NO.:

UN No.

Pk group.

Agg. Net quantity

No. of packages

65

ASPECTS OF S CIENCE M ANAGEMENT

3.2

PREPARATION OF SOLUTIONS AND STAINS

Section 3.2.1 contains information about units, conversion factors and techniques for making solutions. Table 6: Preparation instructions outlines the mass of solute and volume of solvent needed to make a stock solution of a known concentration (usually 0.1M) for commonly needed school experiments. Table 7: Variant concentrations and volumes indicates how to adjust the masses or volumes listed in Table 6 to make solutions of different concentrations. Table 8: Series dilutions outlines a procedure for preparing dilute solutions from a concentrated stock solution.

3.2.1

CALCULATIONS AND TECHNIQUES

3.2.1.1

Conversion factors

For guidance, the relationship between a number of units are indicated. 1cm3 = 1mL = 1 millilitre = (1cc) 1dm3 = 1 litre = 1 L = 1000mL = 1000cm3 = (1000cc) 1M = 1 mol.dm-1 = 1 mole per cubic decimetre = 1 mole per litre = 1 mol.L-1

3.2.1.2

A technique for determining mass

Time may be wasted by measuring mass to a degree of precision in excess of the requirements of the experiment. For most laboratory experiments and solutions precision of +/- 0.1g is quite sufficient. The technique used will depend on the type of balance available. It is acceptable to place a chemical into a beaker placed on the balance pan or onto filter paper. Never place a chemical directly on to the balance pan because many chemicals will react with the material in the pan. Before using a solution it should be checked so that all the solid has dissolved and the solution has been sufficiently mixed to make it homogeneous.

3.2.1.3

A technique for determining mass with greater precision

For certain experiments, e.g. those using a standard solution, it is necessary to determine the mass of a substance with greater precision. In these experiments precision of +/- 0.01g or better is required. The following procedure should be used: (a) (b) (c) (d) (e)

on a balance find the approximate mass of a weighing bottle or watch glass; add approximately the mass of substance required; on a balance that measures to the degree of precision required determine the mass of the weighing container and substance; tip the substance from the weighing container into a beaker containing a small amount of the solvent  do not attempt to empty out all of the residual substance; and determine the mass of the weighing container and residual substance.

The difference between the two masses will indicate accurately the mass of substance in the solvent. This method will enable an approximate amount of substance to have its mass determined accurately, quickly and with precision. This is to be preferred since massing an exact amount to high levels of precision is unnecessarily time-consuming. For example, if 1.38g of a solid is required to make a certain volume of a solution exactly 0.1 mole dm3 or 0.1M, it is better to use the above method and end up with 1.41g. The final concentration will be 0.102M, which while being larger than the required 0.1M, is known with accuracy and precision. 66

ASPECTS OF S CIENCE M ANAGEMENT

3.2.2

SOLUTION PREPARATION

3.2.2.1

Preparing stock solutions including acids and alkalis

Making solutions (a)

Solid solutes dissolved in water (i) Weigh the calculated quantity of solid on a watch glass. (ii) Tip this material carefully from the watch glass into a clean, dry glass beaker. (iii) With a wash bottle, carefully rinse the watch glass into the beaker, by holding the watch glass over the beaker and directing a stream of distilled water over the surface of the watch glass, being careful to prevent splashing. Use the minimum quantity of distilled water. (iv) Add more distilled water, being careful to add less water than is required for the final total volume of solution. Pour the distilled water down a stirring rod into the mixture to prevent splashing. (v) Using the stirring rod, stir the mixture until the solid has dissolved. In some cases, careful heating of the beaker and mixture on a hotplate or on a tripod and gauze over a bunsen assists the solution process. If heat is used, the solution should be cooled before further dilution. (vi) By pouring the solution down a stirring rod, carefully transfer the solution through a filter funnel into the appropriate measuring container (measuring cylinder or volumetric flask). Using a wash bottle, rinse the beaker several times with distilled water, and pour the washings into the graduated container. Rinse also the outside of the stirring rod and the inside of the funnel, allowing the washings to drain into the container. (vii) Carefully add distilled water up to the desired level for the final volume of solution. Stopper and invert several times to mix the solution thoroughly. (viii) Use very small quantities of the solution to rinse out a cleaned stock bottle, then pour the solution through a clean, dry filter funnel into the stock bottle. Stopper and label. (ix) If a solvent other than water is to be used, the procedure is as above except that the measuring cylinder, volumetric flask and stock bottle would be dried then rinsed with small quantities of solvent. The wash bottle would be filled with the appropriate solvent. Note: Many liquids are flammable and heat should not be applied to these unless the Head of Department has been consulted. Solutions in alcohol or methylated spirits should be warmed where necessary over a water bath. Under no circumstances should ether, hexane, petroleum ether (benzine), propanone (acetone), ethyl ethanoate (acetate), or methylethanoate (acetate) be heated over a bunsen: these solvents are extremely dangerous and must not be used on any bench where a bunsen or other heating appliance is alight. (x) If the solute is composed of large crystals or is lumpy, careful crushing of the solute in a clean mortar and pestle may be necessary before weighing. (xi) Where it is not necessary to make up a solution accurately, the above steps may be curtailed, as, for example, by marking the stock bottle to note the final desired volume of solution, by pouring the mixture directly into the stock bottle rather than into a measuring cylinder or volumetric flask first, and by adding solvent to the level that you have marked on the bottle. Stopper and shake thoroughly.

(b)

Liquid solutes dissolved in water

67

ASPECTS OF S CIENCE M ANAGEMENT

(i)

(ii) (iii)

(iv)

As above, the liquid may be massed (in a small beaker). However, more frequently the calculated volume of liquid is carefully measured out using a pipette or measuring cylinder. Note: Pipettes must not be used for any concentrated acid or alkali, or for any other volatile or poisonous liquid. Pour small quantities of the liquid solute down a stirring rod into a small quantity of solvent. Stir frequently. Finally, rinse the container from which the solute was poured with small quantities of the solvent. Pour all rinsings into the solution and dilute the solution to the desired volume. As in (a), modify the above procedures if a solvent other than water is to be used.

Dilution of acids and alkalis (a)

(b)

(c)

(d)

(e)

Acids and alkalis are dangerous materials, especially when they are concentrated. Have calcium carbonate (whiting or chalk), or sodium bicarbonate, on hand when diluting acids. Goggles and gloves should be used. The dangerous acids and alkalis that are commonly used in schools are: • glacial ethanoic (acetic) acid • concentrated hydrochloric (muriatic) acid • nitric acid • sulfuric acid • ammonia solution (ammonium hydroxide) • potassium hydroxide (caustic potash) • sodium hydroxide (caustic soda) Glacial ethanoic (acetic) acid, concentrated hydrochloric acid, concentrated nitric acid and ammonia produce poisonous or extremely irritating gases or vapours. Bottles of these acids should be carefully unstoppered in a fume cupboard. All concentrated acids should be diluted in a glass beaker, by carefully ADDING THE CONCENTRATED ACID IN SMALL QUANTITIES TO WATER WITH CONTINUAL STIRRING, never by adding water to the acid. This general precaution is especially important when diluting sulfuric acid, as large quantities of heat are produced when concentrated sulfuric acid is mixed with water. Dangerous spitting, hazardous to eyes, skin and clothing, can result from the addition of water to the acid or from the too rapid addition of the acid to water. Allow the solution to cool before transferring to stock bottles. Sodium and potassium hydroxides are supplied in solid form, usually as pellets. Bottles of these solid alkalis must be kept airtight as the solids are hygroscopic (absorb water). Frequently the pellets aggregate into a solid mass in the bottle and this solid mass should be carefully dislodged with a stainless steel spatula, sealing the bottle as quickly as possible after removal of the desired solid. These solids must also be weighed quickly because of their tendency to absorb water vapour from the air. Dissolve the pellets in cold water with stirring, using a glass beaker, not a plastic container. As the solution generates a large amount of heat, it should be continually stirred until the solid has dissolved. Then allow the solution to cool before transferring it to stock bottles. Further dilution to the final desired volume in the stock bottle may be necessary. Stopper the bottle firmly and invert several times to mix. All bottles containing solutions of alkalis should be sealed either with plastic screw tops or rubber stoppers, as alkalis attack glass stoppers making them hard to dislodge. Ammonia solution 10% (ammonium hydroxide) produces dangerous irritating ammonia fumes. Bottles of ammonia solution should be carefully unstoppered in a fume cupboard to

68

ASPECTS OF S CIENCE M ANAGEMENT

(f)

(g)

(h)

prevent damage to eyes from the fumes. Dilute by adding ammonia solution to water in a fume cupboard. Limewater (calcium hydroxide solution). This is a weak alkali that is made up by adding slaked lime (calcium hydroxide solid) to distilled water in a large stock bottle. Shake vigorously and allow to stand. Calcium hydroxide solid is only slightly soluble in water. When the white solid has settled as a fine white sediment, carefully siphon off or pour off the clear limewater above the sediment without disturbing the sediment. To replenish the limewater, add more distilled water to the sediment in the stock bottle, shake and allow to settle. The settling process to produce clear limewater may take several days. The clear limewater prepared as above may be diluted 1:2 as desired. Note: Goggles and protective rubber gloves should be worn when carrying out dilutions of concentrated acids or alkalis, but special care should be taken to ensure that the outside surfaces of gloves and bottles are dry to avoid accidental slipping of bottles when handled. Any acid or alkali that contacts the skin should be immediately washed off with copious quantities of water. Then apply dilute sodium bicarbonate solution to the affected area (for acid burns) or very dilute acetic acid or vinegar solution or boracic acid (for alkali burns) to neutralise traces of the acid or alkali. Any spills of acids or alkalis should be diluted as above, before mopping up. For large spills, solid neutralisers such as solid sodium bicarbonate or whiting (for acids) and solid citric acid (for alkalis) should be used. Because of constant use, reagent solutions and solids must be constantly checked and replaced where necessary from stock bottles. The reagent bottles should be labelled with the name of the substance and the concentration of the solution. Note: Unused reagents should never be returned to the stock bottles. The following section lists the acids and alkalis most commonly used and states their approximate strength as supplied in stock.

Stock solutions of acids and alkalis (a)

Acids:

Hydrochloric acid-10 molar-10M Sulfuric acid-18 molar-18M Nitric acid -16 molar-16M Ethanoic (acetic acid) glacial-17 molar-17M

(b)

When diluting acids Hydrochloric acid (10M) to 4M  dilute 400mL of the stock solution to 1 litre with water. Sulfuric acid (18M) to 2M  111mL of 18M acid is poured slowly, while stirring, into 800mL of water. Allow to cool. The whole is then dilute d to 1 litre with water Nitric acid (16M) to 4M  250mL of acid is diluted to 1 litre with water.

(c)

Alkalis Sodium hydroxide, 4M to produce a 4M solution, dissolve 160g of the solid in 500mL of water and dilute to 1 litre. Calcium hydroxide (limewater)  add 125g of slaked lime to one large bottle (about 3 litre capacity) of water and shake. When the excess settles, the clear solution may be siphoned into containers as needed. Potassium hydroxide, 4M to produce a 4M solution  dissolve 224g of the solid in water and dilute to 1 litre. Ammonia solution (ammonium hydroxide), this is supplied as a 10% solution, approximately 6M. For normal class use, a solution of 2M concentration is commonly made. Dilute 330mL of 10% ammonia solution to one litre. 69

ASPECTS OF S CIENCE M ANAGEMENT

3.2.2.2

Preparation instructions

When preparing solutions the number of molecules of water of crystallisation indicated on the bottle should be checked against that given in Table 6: Preparation instructions. If different, a new calculation will be required. The formula after each substance is for its commercial form. In making up solutions, distilled water (or demineralised water) should be used. If none is available, tank water is a suitable substitute. Unless otherwise stated, the amount of material indicated should be dissolved in about one-quarter of the volume of distilled water required and then diluted to the required volume. The symbol ‘M’ stands for molarity, i.e. the number of moles of solute per cubic decimetre or litre of solution. In most cases, the masses are not exact fractions of the formula mass. Instructions for preparing one litre of solution for each reagent are given in Table 6.

Table 6: Preparation instructions S UBSTANCE

FORMULA

C ONC.

PREPARATION OF 1 LITRE OF SOLUTION

ALUMINIUM CHLORIDE

AlCl3.6H2O

0.lM

24g of hydrated salt in water

ALUMINIUM SULFATE

Al2(SO 4)3.18H20

0.lM

66g of hydrated salt in water

AMMONIA

NH 3(aq) or NH40H

2M

dilute 330cm3(mL) of 10% solution

AMMONIUM ETHANOATE (ACETATE)

CH 3COONH 4

3M

230g in water

AMMONIUM CHLORIDE

NH 4Cl

5M

270g in water

AMMONIUM CARBONATE

(NH4)2CO 3.3H2O

2M

300g in water containing 450cm3 (mL) 10% ammonia then dilute.

AMMONIUM IRON (II) SULFATE

FeSO4(NH4)2SO 4.6H2O

0.lM

39.2g in water. Add 5cm3(mL) conc. sulfuric acid

AMMONIUM MOLYBDATE

(NH4)6M o7O 24.4H2O

AMMONIUM OXALATE

C2O4(NH 4)2.2H2O

0.lM

16g in water

AMMONIUM SULFATE

(NH4)2SO 4

0.lM

13.2g in water

BARIUM CHLORIDE

BaCl2.2H 20

0.lM

24.4g in water

BARIUM NITRATE

Ba(NO 3)2

0.lM

26g in water

BROMINE WATER (200 mL only)

Br 2

45g in water containing 120cm3 (mL) 10% ammonia. Add 120g NH4NO 3 then dilute.

Cool 1mL ampoule in refrigerator. Break ampoule with forceps under 200mL water. Decant. *CAUTION-Use gloves 1g in 15cm3(mL) of 0.lM KOH. Dilute to 1dm3 (L) with water.

BROMOPHENOL BLUE CALCIUM CHLORIDE

CaCl2 if fused, anhydrous CaCl2.2H 2O if dihydrate

0.lM

11g of fused salt in water. 14.7g of dihydrate in water

70

ASPECTS OF S CIENCE M ANAGEMENT S UBSTANCE

FORMULA

C ONC.

PREPARATION OF 1 LITRE OF SOLUTION

CALCIUM HYDROXIDE (LIMEWATER)

Ca(OH)2

Saturated

Add slaked lime (calcium hydroxide) to water in a bottle. Stand, decant clear liquid. Use fresh.

CALCIUM NITRATE

Ca(NO 3)2

0.lM

16.4g in water

CALCIUM SULFATE

CaSO4.2H 2O

0.05M

Shake 5g in 1 litre of water. Stand, decant clear liquid only.

CHROMIUM ETHANOATE (ACETATE)

Cr(CH 3COO)3.H 20

0.lM

24.7g in water

CHROMIUM SULFATE

Cr 2(SO 4)3.18H20

0.lM

72g in water

COBALT CHLORIDE

CoCl2.6H 20

0.lM

23.8g in water

COBALT NITRATE

Co(NO 3)2.6H 2O

0.lM

29g in water

COPPER (II) NITRATE

Cu(NO 3)2.6H 2O

0.lM

29.6g in water

COPPER (II) SULFATE

CuS04.5H 20

0.lM

25g in water. Add 5cm3 conc. sulfuric acid.

DI-POTASSIUM HYDROGEN ORTHOPHOSPHATE

K2HPO4

0.lM

17.4g in water

DISODIUM HYDROGEN PHOSPHATE

Na2HPO4.l2H 2O

0.lM

35.8g of Na2HPO4.

ETHANOIC ACID (ACETIC)

or

l2H2O or

Na2HPO4.2H 2O

17.8g Na2HPO 4.2H2O in water

CH 3COOH

17M

As purchased

2M

Dilute 120cm3(mL) concentrated (glacial) (or use 360cm (mL) of 33% acid)

FEHLING'S SOLUTION A

STORE SEPARATE FROM SOLUTION B.

69g CU2S0 4 + 5H20 in 1 litre of water.

FEHLING'S SOLUTION B

STORE SEPARATE FROM SOLUTION A.

346g Rochelle salt KNaC4H 4O 6.4H2O, plus 250g KOH in 1 litre of water

FEHLING'S SOLUTION (MIXED)

Used to test for glucose and maltose (alternative to Benedict's solution)

Mix equal volumes of Solutions A and B just prior to use.

IRON (III) CHLORIDE

FeCl3.6H20

0.lM

27g in water. Add chloride 20 cm3 mL) hydrochloric acid.

IRON (III)NITRATE

Fe(NO 3)3.9H 2O

0.lM

40.4g in water

IRON (II)SULFATE

FeSO4.7H 2O

0.lM

27.8g in water. Add 1mL conc. H 2SO 4 to clear.

IRON (III) SULFATE

Fe2(SO 4)3.9H 20

0.lM

56g in water

HYDROCHLORIC ACID

HCl

Conc. (l0M)

As purchased

2M

Dilute 200 cm (mL) of conc. acid. Use gloves.

71

ASPECTS OF S CIENCE M ANAGEMENT S UBSTANCE

FORMULA

C ONC.

PREPARATION OF 1 LITRE OF SOLUTION

HYDROGEN PEROXIDE

H20 2

Normal lab. use of water

To 20 volume solution add twice the volume of water.

IODINE

I2

Alcoholic

Add a few flakes to methylated spirit.

IODINE

I2/I2I

Aqueous

lg iodine, 5g potassium iodide and 20cm3 (mL) water. Dilute to 1 litre.

I2/I2KI LEAD ETHANOATE (ACETATE)

(CH3COO)2Pb.3H2O

0.1M

38g in water. Add dilute acetic acid to clear.

LEAD NITRATE

Pb(N03)2

0.1M

33g in water.

LITMUS

Boil 5g of granules in a litre of water. Stand. Filter

MAGNESIUM CHLORIDE

MgCl2.6H 20

0.lM

20.3g in water

MANGANESIUM NITRATE

Mg(N03)2.6H 20

0.lM

25.6g in water

MANGANESIUM SULFATE

MgS0 4.7H 20

0.lM

24.7g in water

MANGANESE CHLORIDE

MnCl2.4H 20

0.lM

19.8g in water

MANGANESE SULFATE

MnSO 4.H 20

0.lM

16.9g in water

MERCURY (II) CHLORIDE

HgCl2

0.lM

27g in water

MERCURY (I) NITRATE

Hg2(N03)2.2H 20

0.lM

56g in water. Add a droplet of metallic mercury.

METHYL ORANGE

0.5g in 1 litre of water. Filter if necessary.

METHYL RED

3g in 1 litre of ethanol.

NICKEL CHLORIDE

NiCl2.6H20

0.lM

24g in water

NITRIC ACID

HNO3

Conc. (16M)

As purchased

2M

Dilute 125 cm3(mL) of conc. acid. Use gloves.

0.lM

12.6g of crystals in water

OXALIC ACID

(COOH)2 + 2H2O

PHENOLPHTHALEIN

5g in 500mL of ethanol, add 500mL water. Stir.

POTASSIUM BROMIDE

KBr

0.lM

12g in water

POTASSIUM CARBONATE

K2CO 3

0.lM

13.8g in water

POTASSIUM CHLORIDE

KCl

0.lM

7.5g in water

POTASSIUM CHROMATE

K2CrO 4

0.lM

19.4g in water

POTASSIUM DICHROMATE

K2Cr 2O7

0.lM

29.4g in water

POTASSIUM DIHYDROGEN ORTHOPHOSPHATE

KH 2PO4

0.lM

13.6g in water

POTASSIUM HEXACYANOFERRATE (III)

K3Fe(CN)6

0.lM

33g in water

72

ASPECTS OF S CIENCE M ANAGEMENT S UBSTANCE

FORMULA

C ONC.

PREPARATION OF 1 LITRE OF SOLUTION

POTASSIUM HEXACYANOFERRATE (II)

K4Fe(CN)6 . 3H 20

0.lM

42.2g in water

POTASSIUM HYDROXIDE

KOH

2M

112g in water (as for sodium hydroxide). Use gloves.

POTASSIUM IODATE

KIO3

0.lM

21.4g in water

POTASSIUM IODIDE

KI

0.lM

16.6g in water

POTASSIUM NITRATE

KNO3

0.lM

10.lg in water

POTASSIUM NITRITE

KNO2

0.lM

8.5g in water

POTASSIUM MANGANATE (VII) (PERMANGANATE)

KMnO 4

0.lM

15.8g in water

POTASSIUM SULFATE

K2SO4

0.lM

17.4g in water

POTASSIUM THIOCYANATE

KCNS

0.lM

9.7g in water

SILVER NITRATE

AgNO 3

0.lM

17g in water (distilled)

SODIUM BORATE

Na2B4O7.l0H 2O

0.lM

38g in water

SODIUM CARBONATE

Na2CO 3.1OH 2O

0.lM

28.6g in water

Na2CO 3(anhydrous)

(10.6g if anhydrous)

SODIUM CHLORATE (I) (HYPOCHLORITE)

NaClO

Dilute 10% solution with an equal volume of water.

SODIUM CHLORIDE

NaCl

0.lM

5.8g in water

SODIUM CHROMATE

Na2CrO4.4H20

0.lM

23.4g in water

SODIUM DICHROMATE

Na2Cr 207.2H 20

0.lM

29.8g in water

SODIUM DIHYDROGEN PHOSPHATE

NaH2PO4.2H 20

0.lM

15.6g in water

SODIUM ETHANOATE (ACETATE)

CH 3COONa.3H2O

00.lM

13.6g in water

SODIUM HYDROGEN CARBONATE

NaHCO3

0.lM

8.4g in water

SODIUM HYDROSULFITE (DITHIONITE)

Na2S20 4.2H20

For 100mL solution for use as oxygen absorber

16g Na2S20 4.2H 20 +

SODIUM HYDROXIDE

NaOH

2M

80g slowly to water in a beaker in a sink. When cool dilute. Store in bottle with rubber stopper. Use gloves

SODIUM IODIDE

NaI

0.lM

15g in water

SODIUM MOLYBDATE

Na2MoO 4.2H20

0.lM

24.2g in water

SODIUM NITRATE

NaNO 3

0.lM

8.5g in water

SODIUM NITRITE

NaNO 2

0.lM

7g in water

13g NaOH in 100mL water. Addition of 4g of B-anthraquinone sulfonate improves quality of reagent.

73

ASPECTS OF S CIENCE M ANAGEMENT S UBSTANCE

FORMULA

C ONC.

PREPARATION OF 1 LITRE OF SOLUTION

SODIUM OXALATE

Na2C20 4

0.lM

13.4g in water

SODIUM SULFATE

Na2SO 4.10H20

0.lM

32.2g in water

SODIUM SULFITE

Na2SO 3.6H20

0.lM

23.4g of hydrated salt in water (salt must be fresh) or, 12.6g of anhydrous salt

0.lM

24.8g in water

1%

To 10g starch add cold water to make a paste. Then add to 1 litre of boiling water, stir and allow to stand.

0.lM

26.7g in water

Conc. (18M) 1M

As purchased. Pour 55 mL conc. acid slowly into water with stirring (beaker in a sink). Cool. Use gloves.

Na2S0 3(anhydrous) SODIUM THIOSULFATE

Na2S20 3.5H20

STARCH

STRONTIUM (II ) CHLORIDE

SrCl2.6H20

SULFURIC ACID

TRISODIUM PHOSPHATE

Na3P0 4.12H20

0.lM

38g in water

TIN (II) CHLORIDE

SnCl2.2H20

0.lM

22.6g in 100 mL conc. hydrochloric acid then dilute. Add pieces of tin.

TIN (IV) CHLORIDE

SnCl2.5H20

0.lM

35g in water

ZINC SULFATE

ZnS04.7H 20

0.lM

28.8g in water

Where concentrations other than those shown in Table 6 are required, simple calculations are necessary to find the correct quantity of solute and/or solvent needed.

3.2.2.3

Table 7: Variant concentrations and volumes Variant concentration and volumes

Example

If the solution required is more concentrated, more solute is required to be dissolved in the same volume (here, one litre) of solution.

Suppose 4M sodium hydroxide is required. The table gives the quantity of solid (80g) required to make 1 litre of 2M solution. 4M is 2 = 2 x concentration of 2M. Thus 2 x 80g = 160g NaOH must be dissolved in 1 litre to make a 4M solution.

If the solution required is less concentrated, less solute is required to be dissolved in the same volume (here one litre) of solution.

Suppose 0.01M sodium iodide is required. The table gives the quantity of solid (15g) required to make 1 litre of 0.1M solution. 0.01M is one-tenth as concentrated as 0.1M. Therefore one-tenth of 15g is required, i.e. 1.5g so 1.5g of sodium iodide must be dissolved in 1 litre to make a 0.01M solution.

If larger or smaller volumes of solutes are required, appropriate conversion factors must be used. A frequently

Suppose a Winchester bottle (2.4 litres) of 2 M sulphuric acid is required. From Table 6,

74

ASPECTS OF S CIENCE M ANAGEMENT Variant concentration and volumes used quantity is the volume of a Winchester bottle used as a stock bottle. This, and many of the large plastic containers sold as detergent or disinfectant bottles which are frequently used by schools to hold reagents, have a volume of about 2.4 litres. Check the approximate volume of any such container before using it. The quantity of solute required would be 2.4 times the quantity listed in Table 6.

Example 55mL concentrated acid makes 1 litre of 1M solution 110mL concentrated acid makes 1 litre of 2 M solution 110 x 2.4mL concentrated acid makes 2.4 litre of 2 M solution, i.e. 264mL concentrated acid makes 2.4 litre of 2M solution.

75

ASPECTS OF S CIENCE M ANAGEMENT

3.2.2.4

Series Dilution

A number of experiments require solutions of the one chemical with varying percentage concentrations. These solutions can usually be prepared by series dilution. The following table may serve as a guide.

Table 8: Series dilutions % Solution

3.2.3

Instructions for preparation

100

Prepare 100cm3(mL) of a saturated solution at room temperature; filter to remove excess solid.

0.5

Measure 0.5cm3(mL) in a graduated pipette of 100% solution and dilute with water to 100cm 3(mL) in a volumetric flask.

0.1

Pipette 20cm3(mL) of 0.5% solution into a 100cm3(mL) volumetric flask and fill to the mark with water.

0.05

Pipette 50cm3 (mL) of 0.1% solution into a 100cm3(mL) volumetric flask and fill to the mark with water.

0.01

Pipette 20cm3(mL) of 0.05% solution into a 100cm3(mL) volumetric flask and fill to the mark with water.

0.005

Pipette 50cm3 (mL) of 0.01% solution into a 100cm3 (mL) volumetric flask and fill to the mark with water.

0.001

Pipette 20cm3 (mL) of 0.005% solution into a 100cm 3 (mL) volumetric flask and fill to the mark with water.

SOME USEFUL CHEMICAL INDICATORS

Cobalt chloride paper (used to test for the presence of water). • • • • • • • • •

Prepare a solution of cobalt chloride by dissolving 5g of the salt in 100mL distilled water. Cut up strips of filter paper approximately 5cm x 1cm. Soak the strips of filter paper in the cobalt chloride solution. Remove and drain the strips of paper. Separate the strips and spread them out flat on watch glasses or an enamel metal tray. Place the drying trays in a drying oven at 100 oC and dry for one hour or until the strips are blue in colour. Remove the drying trays from the oven while still hot, and with forceps, place the strips in a bottle containing dry silica gel (blue in colour) or anhydrous calcium chloride covered with a little dried cotton wool or cotton gauze. Keep the bottle sealed, preferably in a desiccator. When using the paper, use it immediately after removing it from the bottle. If the paper turns pink, heat it again as described above until it turns blue again. Do not handle the paper with fingers as moisture from the skin will affect it.

Phenyl thiocarbamide (PTC) paper (for tasting experiments) •

Phenyl thiocarbamide is also called phenyl thiourea. Note that this substance is toxic but is considered to be safe for tasting experiments, if used at a concentration of no more than 0.13%. 76

ASPECTS OF S CIENCE M ANAGEMENT

• • • • • • • •

Weigh 0.13g of the solid on a watch glass. Dissolve the solid in 100mL distilled water. Cut strips of filter paper 5cm x 1cm. Soak the strips in the solution, remove with forceps, drain and dry the papers on a drying tray in an incubator at no more than 50oC. Store the papers in a sealed bottle. Strips of paper soaked in solutions twice or ten times as dilute may be prepared in the same manner after diluting the above solution 50mL to 100mL or 10mL to 100mL respectively with distilled water. The mouth should be well rinsed after each tasting trial. Note: The chemical has a very bitter taste, which persists for some time. It is advisable, therefore, that the strips of paper be handled only with forceps.

Universal indicator This is a fairly cheap alternative to buying the prepared indicator solution. Dissolve in 500mL ethanol all of the following: 0.0250g thymol blue 0.0625g methyl red 0.5000g phenolphthalein 0.2500g bromothymol blue. Dilute this solution to 1 litre with distilled water. Add drops of 0.05M sodium hydroxide till mixture is green. Orcinol-Bial's Reagent •

Dissolve 0.2g orcinol in 100mL concentrated hydrochloric acid (caution  corrosive).

Red cabbage (to test for presence of acid/alkali)

3.2.4

SOME USEFUL BIOLOGICAL SOLVENTS, ADHESIVES, STAINS, FIXATIVES AND BUFFER SOLUTIONS

3.2.4.1

General purpose solutions

Alcohol (ethanol) Alcohol is used in various concentrations for preserving, dehydrating etc. Absolute alcohol bottles must be stoppered at all times, since alcohol readily absorbs water from the atmosphere. Water can be removed from alcohol by using drying agents, such as anhydrous copper (II) sulfate. Xylene, methylbenzoate These are used during staining procedures. These chemicals are highly flammable, toxic and readily absorbed through the skin. Care must be exercised when handling. These are not miscible with water. Acid alcohol A mixture of 100mL 70% alcohol and 1mL hydrochloric acid is used for cleaning slides and cover slips and decolourising some stains, e.g. Haematoxylin. Carbol xylol 25g phenol mixed with 100mL xylene is used for dehydrating in staining techniques. It dissolves slowly, and cools when dissolving. Take care when handling phenol, it is a powerful skin irritant: use gloves. Iodine solution Iodine solution can be made as follows: 77

ASPECTS OF S CIENCE M ANAGEMENT

lg iodine crystals 2g potassium iodide 100mL distilled water Dissolve potassium iodide first in water then add iodine crystals. Besides being a test for starch, iodine solution is useful in dissolving mercury (II) chloride from tissue that has been preserved in a fixative containing that chemical. Sodium thiosulfate solution 5g of sodium thiosulfate dissolved in 100mL distilled water decolorises and washes iodine from tissue. Scott's blueing solution Scott’s blueing solution is used instead of tap water when tissues are washed during staining processes, particularly with haematoxylin to develop blue colour. The solution is made as follows: 2g sodium bicarbonate 20g magnesium sulphate 1 litre distilled water. Saline 9g sodium chloride dissolved in 1 litre of distilled water makes a saline solution suitable for many biological purposes. Ringer solution Ringer solution can be made as follows: 0.9g sodium chloride 0.042g potassium chloride 0.025g calcium chloride 100mL distilled water (This must be prepared fresh before use.)

3.2.4.2

Adhesives

These are used to stick sections, small animals etc. to microscope slides. Haupt's adhesive 1g gelatine dissolved in 100mL distilled water at 30 oC in a water bath or oven. Add 2g phenol crystals and 15mL glycerin. Stir, cool and filter. Meyer's albumen Beat an egg white until well broken up, but not stiff. Pour into a tall cylinder, allow to stand overnight. Collect liquid from bottom. Add to it equal volume of glycerin. May be filtered, but it is not necessary. Add a crystal of thymol to prevent growth of fungus. Glycerine jelly Glycerine jelly is made as follows: 10g gelatine 70mL glycerine 1g phenol crystals 60mL distilled water. Soak the gelatine in the water for about 2 hours. Add the glycerine and phenol. Heat the solution gently in a water bath and then let it cool. To soften the jelly before embedding material, heat up to a maximum temperature of 40oC (e.g. in a water bath).

78

ASPECTS OF S CIENCE M ANAGEMENT

3.2.4.3

Stains

Acetocarmine Acetocarmine is made as follows: • • •

concentrated ethanoic acid (glacial acetic acid) 45mL 0.5g carmine 55mL distilled water

Aceto-orcein stain Aceto-orcein stain is used as a chromosome stain for smears and squashes. It is made as follows: • • •

add lg of synthetic orcein (e.g. Gurr's or BDH) to 25mL concentrated ethanoic acid (glacial acetic acid) and 20mL distilled water; boil for 4 to 5 minutes  no longer  in a narrow-necked flask, fitted with a glass filter funnel to act as a condenser, then filter the solution while still hot; add 5mL concentrated ethanoic acid and stir to dissolve any orcein appearing on the surface of the mixture after filtration.

Three or 4 drops of glycerol may be added if desired. This helps to retard evaporation of the stain from temporary squash mounts. Aceto-orcein stain keeps for years if tightly stoppered, but may require refiltration after prolonged standing. Acetic alcohol Mix 99mL 70% ethanol with 99mL concentrated ethanoic acid. This solution should be prepared immediately before use. Alcoholic -hydrochloric acid-carmine stain Alcoholic-hydrochloric acid-carmine stain is made as follows: • 4g carmine • 1mL conc. hydrochloric acid • 15mL distilled water Boil gently in a fume cupboard for 10 minutes with continuous stirring. Cool, and add 95mL 85% ethanol (alcohol). Filter. Aniline hydrochloride Prepare a saturated solution in distilled water, filter, then add a few drops of hydrochloric acid until the solution is distinctly acid. CAUTION  use gloves. Aniline sulfate Prepare as for the hydrochloride, but use sulfuric acid. CAUTION  use gloves. Counter stains These are used to stain cell walls and cell contents. (a)

Eosin (stock solution for animal tissues) 1g Eosin Y powder 1000mL 70% ethyl alcohol (ethanol) 5mL glacial acetic (ethanoic) acid Use this stain by diluting 100mL of it with 100mL 70% alcohol, add 2-3 drops of glacial acetic (ethanoic) acid.

(b)

Orange G (for botanical tissues) 0.5g powder dissolved in 100mL 95% alcohol. 79

ASPECTS OF S CIENCE M ANAGEMENT

2,6-Dichlorophenol-indophenol 2,6-Dichlorophenol-indophenol is used to show action of enzymes such as succinic dehydrogenase, and the action of chloroplasts when exposed to light. It is also used to test for vitamin C. It is made as follows: • • • • •

4g carmine and 1mL conc. hydrochloric acid is added to 15mL distilled water; boil gently in a fume cupboard for 10 minutes with continuous stirring; cool, and add 95mL 85% ethanol (alcohol); filter, add 1g 2,6-Dichlorophenol-indophenol and 1L water.

Gram stain 1g Gentian violet (or crystal violet) 100mL distilled water Haematoxylin Haematoxylin is a most important natural dye and also the most expensive. A stock solution of 10% haematoxylin in 95% alcohol is very useful in the laboratory. From this, various staining solutions are prepared easily. Haematoxylin is particularly useful in showing nuclei in plant and animal cells. There are various types of haematoxylin. Weigert's haematoxylin is used for animal tissue, Delafield's haematoxylin for botanical tissue and Heidenhain iron haematoxylin for both. (a)

Weigert's iron haematoxylin (Part A) 2.5g iron (III) chloride FeCl3.6H 2O 4.5g iron (II) sulfate FeS0 4.7H2O 2mL hydrochloric acid 298mL distilled water (Part B) 1g haematoxylin 100mL 95% ethanol

The two solutions may be kept separately for years. Mix 1 part of B to 3 parts of A just before use. This mixture has a shelf-life of 2-3 weeks. (b)

Heidenhain iron haematoxylin (Part A) 4g FeNH4(S04)2.12H 2O (Ferric alum i.e. Iron (III) ammonium sulfate) 100mL distilled water (Part B) 10g haematoxylin 100mL 95% ethanol

Mix equal quantities of A and B. The mixture is useful for a few hours only. Solution A is used as a mordant and B is for staining. (c)

Delafield’s haematoxylin Delafield’s haematoxylin can be obtained in powder form and made up to 1% Delafield’s haematoxylin in 20% alcohol, or prepare the stain from ordinary haematoxylin, by: • dissolving 4g of powder in 25mL absolute ethanol; 80

ASPECTS OF S CIENCE M ANAGEMENT

• • • •

mix gradually into 400mL saturated aqueous alum, NH4Al(S0 4)2.12H2O; allow to stand for 3-5 days with a cotton plug in flask, exposed to direct light; filter, add 100mL glycerin and 100mL methanol; allow to ripen for at least 6 weeks.

Iodine solution (Gram's) 1g iodine 2g potassium iodide 300mL distilled water Dissolve potassium iodide in water, then add iodine. Iodine solution (Lugol) 4g iodine 6g potassium iodide 100mL distilled water Karo syrup mountant 40mL clear Karo syrup 40mL distilled water 1-2 small crystals thymol (or phenol) (about 0.2g) as preservative Lactophenol 25g phenol 25mL lactic acid 50mL glycerine 50mL distilled water Dissolve phenol in water, then add lactic acid and glycerine. Keep away from light. Caution−use gloves. Lactophenol cotton blue 100mL lactophenol lg cotton blue For use, dilute 5mL to 100mL with lactophenol. Leishmann's stain Place 0.115g of Leishmann's stain with 100mL of pure methanol in a flask, plug the neck with cotton wool and warm in a water bath for 15 minutes with occasional shaking. Wright's stain can often be used instead of Leishmann's. It is purchased ready-made. Methylene blue (0.1%) 0.1g methylene blue 100mL distilled water For vital staining it is often advisable to dilute 1mL in 10. Neutral red (0.1%) 0.1g neutral red 100mL distilled water Use only clear solution. Dilute 1 in 10. Phloroglucinol (10% solution) Phloroglucinol is used to stain lignin in plant cells. Dilute by volume. Safranin (for Gram's stain) 0.02g safranin 81

ASPECTS OF S CIENCE M ANAGEMENT

10mL 5% ethanol 100mL distilled water Dissolve the safranin in ethanol then add the water. A 1% aqueous solution of safranin can be used to stain lignin in plant cells. Schulze's solution (chlor-zinc-iodine) 20g zinc chloride 9.5mL distilled water Dissolve in warm water, then cool, add drop by drop the following solution until a persistent precipitate of iodine forms: 0.5g iodine 1g potassium iodide 20mL distilled water. About 1.5mL of this iodine solution is required.

3.2.4.4

Fixatives

For plant material: FAA Formalin (40% methanal) Ethanol (alcohol), 70% Ethanoic (acetic) acid, glacial

5mL 90mL 5mL

CRAF

Chromic acid, 1% Formalin (40% methanal) Ethanoic (acetic) acid, glacial Distilled water

40mL l0mL 5mL 5mL

Aceto-alcohol

Absolute ethanol (alcohol) 30mL Ethanoic (acetic) acid, glacial l0mL Mix immediately before use, discard after 1 hour.

For animal material: Formol-saline (for marine animals)

Zenker's Fluid

3.2.4.5

Formalin (40% methanal) Sodium chloride, 10% solution Distilled water

l00mL 7mL 83mL

Potassium dichromate Mercury II chloride Distilled water Ethanoic (acetic) acid, glacial

2.5g 5.8g 95mL 5mL

Buffer solutions

By mixing an acid with its conjugate base, definite hydrogen ion concentrations, within a certain range depending on the dissociation constant of the acid, are obtainable. Such solutions have the advantage that evaporation will not affect the value of [H +] for the ratio [acid]/[base] remains constant. Contamination by small quantities of acidic or basic impurities will have no appreciable effect on the pH.

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ASPECTS OF S CIENCE M ANAGEMENT

Table 9: Standard buffer solution The table below shows how to prepare buffer solutions for a particular pH by mixing pairs of the following four solutions. Solution A = 0.lM boric acid, prepared by dissolving 3.09g of AR boric acid and 3.73g of potassium chloride in water and making up the solution to 500mL in a measuring flask. Solution B = 0.lM sodium hydroxide, prepared by diluting standard sodium hydroxide. Solution C = 0.lM citric acid, prepared by dissolving 9.60g of AR citric acid in water and making up the solution to 500mL in a measuring cylinder. Solution D = 0.2M disodium hydrogen phosphate, prepared by dissolving 17.82g of pure Na2HPO4.2H 2O in water, and making up the solution to 500mL in a measuring cylinder. pH

Solution A mL

Solution B mL

pH

Solution C mL

Solution D mL

10.0

25

21.8

6.0

14.6

25

9.6

25

18.0

5.6

18.1

25

9.2

25

13.0

5.2

21.6

25

8.8

25

8.0

4.8

25

24.3

8.4

25

4.0

4.4

25

19.8

8.0

1.4

50

4.0

25

15.7

7.6

3.4

50

3.6

25

11.9

7.2

3.8

25

3.2

25

8.2

6.8

7.4

25

2.8

25

8.2

6.4

11.1

25

2.4

50

3.4

3.2.5

RECENT CHANGES TO WORKPLACE HEALTH AND SAFETY LEGISLATION

General comments The number of deaths that occur in Australia each year from occupational exposure to hazardous substances has been estimated to be about 2300 (reported by Worksafe Australia from National Institute of Occupational Health and Safety Report, April 1996). Countless other people have had their health severely affected in ways that limit their efficiency and change their quality of life. These findings have led to significant recent changes in national and Queensland legislation. These changes require additional emphasis of certain aspects already detailed in Aspects of Science Management: A Reference Manual for Schools. There are also extended mandatory obligations of the principal, teachers and all other people at each school, particularly with respect use of hazardous substances and specified dangerous goods.

83

ASPECTS OF S CIENCE M ANAGEMENT

A number of changes have also been made to legislation affecting electrical safety, which mainly affect the use of safety switches such as earth-leakage devices (see section 4.2.9 in this binder). Hazardous substances legislation Responsible people should be aware of the following legislation: a) Workplace Health and Safety (Hazardous Substances) Compliance Standard requiring: • material safety data sheets for all hazardous substances in use at the workplace; • register of material safety data sheets; • documented risk assessments and controls for all hazardous substances; • documented training and supervision of workers in their use; • special requirements for labelling; • knowledge of the need to monitor or use health surveillance procedures with certain hazardous substances (not normally used at schools but occasionally used by groundspeople). b)

Workplace Health and Safety (Hazardous Substances) Advisory Standard (in preparation, soon to supersede the Code of Practice for the Management of Hazardous Substances at Work ) which gives further information on implementation of the preceding Compliance Standard.

c)

Regulation Part 17 Specified Dangerous Goods requires:

• material safety data sheets for specified dangerous goods; • adequate labels on containers; • suitable depots, adequately maintained, for storage of dangerous goods; • adequate instruction of persons, and training of workers to operate safety equipment; • the making and recording of a risk assessment and controls for each specified type of dangerous goods; • preparation of an emergency plan and manifest of goods on site; • adequate procedures for storage and handling of specified dangerous goods on site; • reasonable precautions to prevent incidents and fire hazards. What is a hazardous substance? The Workplace Health and Safety (Hazardous Substances) Compliance Standard specifies a ‘hazardous substance’ in section 8 as: • a designated hazardous substance (i.e. a substance listed in the Worksafe Technical Report List of Designated Hazardous Substances [NOHSC:10005(1994)], or • a substance that is not a designated hazardous substance but meets the approved criteria.(i.e. included in the Worksafe Standard Approved Criteria for Classifying Hazardous Substances [NOHSC:(1994)]. This information is not always that straightforward for the user to apply. Whenever possible, the responsible person should ask the manufacturer or supplier of a substance to be used in a workplace whether it is a ‘hazardous substance as defined by the Workplace Health and Safety legislation’. These people have the direct responsibility to determine and communicate whether their product is a ‘hazardous substance’ under this legislation. Retailers, e.g. supermarkets, although not required to 84

ASPECTS OF S CIENCE M ANAGEMENT

know this information or to supply Material Safety Data Sheets, may still do so and should at least be able to give details of the supplier and facilitate such communication. The National Code of Practice for the Labelling of Workplace Substances ([NOHSC:2012(1994)], section 7) specifies that a container label should indicate that a substance is hazardous in the following ways: • by the use of the signal words, ‘Warning’, ‘Poison’, or ‘Dangerous Poison’ (as may be required by poisons legislation), or • by the presence of diamond-shaped class labels indicating that the substance is dangerous according to the Australian Dangerous Goods Code. In each of these situations, the substance is most probably (but not certainly) a designated hazardous substance. Where the signal word ‘HAZARDOUS’ is highlighted on the label, the substance is a designated hazardous substance. Another way of determining whether a product is a ‘hazardous substance’ is to look at the Material Safety Data Sheet for the product. If the health hazard information section specifies the following descriptions as effects of the product on the skin, eyes, or respiratory system or if swallowed by the person, then the substance is almost certainly hazardous under the legislation: • • • • •

Very toxic Toxic Harmful Very corrosive Corrosive

• • • •

Irritant Carcinogen Mutagen Teratogen

Once a product is diluted or mixed with another substance, advice should be sought as to whether the substance is still designated as being hazardous. Alternatively, for dilution effects, one could refer to the concentration cut-off levels in the ‘List of Designate d Hazardous Substances’ and determine whether the diluted product is now below the lowest cut-off concentration specified for the designated hazardous substance. For example, equal to or above 5.0 % (w/w) ammonia solutions are designated as being an irritant. Equal to or above 10 %, they are designated as being corrosive. Below 5.0 %, they are no longer designated a hazardous substance although care with their use is still desirable. When considering the effect of mixing products with other substances, one should follow any manufacturer’s instructions. Through contact of input ingredients in mixtures with unsuitable substances, new substances may be generated which themselves could pose risks to the users through additive effects due to their chemical nature. In science activities, reference books and procedures should be consulted prior to the practical activity producing chemical compounds. Material Safety Data Sheets (MSDS) and registers Section 3.3 in this manual substantially addresses the use and value of MSDS. It is mandatory that an MSDS be available for every hazardous substance and that anyone using such substances undergo recorded training to understand their use. Copies of MSDS must be accessible to all people using a hazardous substance as well as those working nearby. The (Hazardous Substances) Advisory Standard or Code of Practice for the Management of Hazardous Substances outlines the proper approach to this information gathering and the risk assessment and control process. This process has been outlined in Chapters 1 and 2.

85

A SPECTS OF S CIENCE MANAGEMENT

Table 1: Example of a register of hazardous substances Page ID No.

Name of substance

Location

MSDS date

Risk assessment date

Labelling OK?

of Comments

.

ASPECTS OF SCIENCE M ANAGEMENT

This management of hazardous substances is detailed practically in Guidance Note for the Assessment of Health Risks Arising from the Use of Hazardous Substances in the Workplace [NOHSC:3017(1994)], Worksafe Australia. Useful examples of registers and assessments are given. It is mandatory that a register be available to provide a listing of every hazardous substance used related to a corresponding MSDS. The form of the register is not prescribed. Table 1 shows one example from the above reference but it has been modified to assist management of the recording process. It is important to have the same sequence relationship between the register and order of filed MSDS to facilitate location of an MSDS. Preparation of this register should be dynamic. Initially, only each identified hazardous substance’s name is recorded into the required column. The use of an ID number and location are optional. Then, as the MSDS for each hazardous substance is obtained, the date of its issue is entered. If this date is more than five years old, the supplier should be asked to provide a more recent copy. Manufacturers must review their MSDS at least once every five years to ensure they contain current information. A documented risk assessment and control must be prepared for every designated hazardous substance used at each education facility. These must be reviewed at least every five years or whenever the activity or associated information changes. Hence, it is useful to record the risk assessment date to enable ready access to this data. If one of these two ‘date’ columns for a substance shows a space, this indicates that either the MSDS or the risk assessment has not been organised at this date. The next column is included to indicate whether appropriate labelling has been organised for containers of any decanted hazardous substances. Preparation and documentation of risk assessment and control process Information and examples are given in the references detailed in the previous section. However, the following example of a risk assessment is provided to summarise the general approach. Table 2 represents a simple risk assessment for the preparation of acid solutions in a science preparation room. Advantage is taken to use a generic risk assessment approach for five different acids with care taken to ensure that the tasks, exposures routes and controls are consistent for each hazardous substance. The same process can also be used with only one entry a form where individual substances require separate evaluation. Nitric acid has been selected as being fully representative of the hazards of the group. The information from the ‘Health hazards information’ section of the relevant Material Safety Data Sheet for nitric acid is summarised for the health hazards posed to skin, eyes, respiratory system and to ingestion. This is recorded in the ‘Hazard Information’ column. The health hazards must be related to the conditions of actual use of the hazardous substance in the workplace. Therefore, a concise description of the actual tasks is put down in the ‘Task’ column which details sufficient detail for one to appraise the risks. Under the example work conditions, the possible route of exposure by humans recorded for the acids includes skin, eyes and respiratory system but not ingestion. With task 2, where the hazards involve only the 1 Molar concentration solutions, the risk of fumes affecting the respiratory system are insignificant so only eyes and skin are recorded in the exposure route. In the ‘Controls’ column, the contents entered depend upon the assessment of the ‘Precautions for use’ section of the MSDS related to the actual workplace conditions. Since 1 Molar acid solutions are still hazardous, the necessary controls have been taken as being similar to those for the concentrated acids.

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The ‘Comments’ column and the ‘Controls in place’ section include relevant information supporting the assessment covering possible emergency situations and extra precautions.

76

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Risk assessment of hazardous substances Work Unit (Job):

Generic Risk Assessment —Preparation of Acid Solutions

Work Area:

Science Preparation Room

Summary of Process:

Dilution of concentrated acids and decanting into laboratory equipment.

Person’s name(s)/Position Lab. Technician

Assessment team: Charles Ivin and Mary Thomas Date:

Hazardous Substances

Hazard information

Task

Exposure routes

Nitric Acid (Conc.)

Highly corrosive to eyes & skin

1. Dilute concentrate to stock solutions (1M)

1. Skin/eyes/respiratory

Work in well-ventilated area Wear goggles, PVC gloves, lab coat, covered shoes

2. Dilute into volumetric flasks, beakers, reagent bottles and student sample test -tubes. Transfer of diluted solutions.

2. Skin/eyes

2. As above

Irritating and corrosive to respiratory system If swallowed, causes severe burns

Sulphuric Acid (Conc.) Hydrochloric Acid (Conc.) Acetic Acid (Glacial) Perchloric Acid (Conc.)

TAKE

AS

Controls in place: Preparation takes place in open room. Safety shower/eye wash facility adjacent to work. Safety volumetric dispensers used to transfer concentrate to reagent bottles and student test tubes. Respiratory equipment (acid vapours) readily available in case of spillage. Sodium carbonate powder available for acid spills. First-aid facilities. Assessment result and recommendations:

Controls

22 November 2001

Comments 1. Take precautions with heat evolution. Add acid slowly to water while stirring! 2. Ensure diluted solution correctly labelled with name, safety and risk phrases.

ABOVE

ASSESSMENT

Perchloric and nitric acids are powerful oxidising agents and require isolation from magnesium or aluminium powders, and finely divided organic substances.

A SPECTS OF S CIENCE MANAGEMENT

Significant risk but effectively controlled. No monitoring or health surveillance required.

Approved by/Name:

Assessor’s Signature:

Signature:

Date:

/

/

Date:

/

/

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Lastly, the assessment concludes with the assessment risk conclusion and whether monitoring or health surveillance is required. Although the assessment team should sign the record, it should also be signed by the responsible person for the school (e.g. the principal or Head Science Master), thus accepting the controls as being mandatory for users of the hazardous substances. Assessments indicating significant risk must be held for 30 years. Otherwise, they need to be held for a period of only 5 years. Labelling of decanted hazardous substances This is amply covered in section 3.3 of this manual. Essentially, if a hazardous substance is transferred to a new container and is not being used immediately, then it must be labelled with the product name, the risk phrases and the safety phrases. The latter two items should be found on the label or from the MSDS and, much less conveniently, may be determined from the List of Designated Hazardous Substances [NOHSC:10005(1994)]. References Available from the Commonwealth Government Bookshop Tel. (07) 3229 6822: List of Designated Hazardous Substances [NOHSC:10005 (1994)] Approved Criteria for Classifying Hazardous Substances [NOHSC:1008 (1994)] National Code of Practice for the Labelling of Workplace Substances [NOHSC:2012 (1994)] Guidance Note for the Assessment of Health Risks Arising from the Use of Hazardous Substances in the Workplace [NOHSC:3017(1994)] Available from GoPrint Tel. (07) 3246 3399: Workplace Health and Safety (Hazardous Substances) Compliance Standard Code of Practice for the Management of Hazardous Substances in the Workplace (to be replaced with an Advisory Standard)

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3.3

MATERIAL SAFETY DATA SHEETS

For the most comprehensive information on any particular chemical, refer to the appropriate Material Safety Data Sheet (MSDS) and any other information supplied by the manufacturer or chemical supplier. MSDS information may also be available from a number of commercial sources. MSDS data are the authoritative sources for all information about chemicals. Material Safety Data Sheets (MSDS) list comprehensive information including: • • • • • • • • • •

hazchem, class and sub-risk information, and Emergency Procedure Guidelines (EPGs); poison information; packing and special storage information; trade names, formulae, manufacturers’ codes, uses and synonyms; ingredients/contaminants of manufacture; physical description and properties including specific gravity, flash point, explosive limits, pH, solubility, vapour pressure and evaporative properties; health hazard information for eyes, skin, inhalation, ingestion and chronic effects, and first aid; precautions for use; safe handling information; additional information including a bibliography of source information for the MSDS data.

MSDS information for additional chemicals that are not on existing MSDS disks can be obtained from chemical suppliers when ordering. Depending on the size and nature of a school, different MSDS procedures may be appropriate. Hard-copies of MSDS can constitute a very large amount of paper, and much of this information has specific relevance to industrial workplaces where the particular chemical is used in large quantities and/or over an extended period. Hence, the health risks and hazards for an industrial workplace may be different from those in schools where there is only occasional use of small amounts of chemicals. To fulfil Workplace Health and Safety Act requirements, schools will need to demonstrate that they have made MSDS information available to those using chemicals. It is likely that schools will keep at least two sets of hard-copy MSDS information  one set available in the central administration area for reference by school administration and as a back-up for a second set that is kept in, or near, the central chemical storage area. Additional sets, or appropriate subsets, may need to be kept in larger schools where different storage areas are maintained. Some schools may keep the MSDS information on a dedicated or network computer system. Whichever information storage/retrieval system is employed, the key principle to be observed is that the MSDS information has been made available to all users of the chemicals in use, and users have understood the relevant information. Students should have salient MSDS information provided before handling any chemicals. This is usually done verbally by the teacher but might also include summarised printed MSDS information on student ‘fact sheets’. Some schools provide laminated MSDS ‘fact sheets’ with the tote-box kits of chemicals and equipment that are prepared for specific experiments. MSDS may be useful as sources of information for students who are researching particular chemicals and industrial procedures. 78

ASPECTS OF SCIENCE M ANAGEMENT

MSDS need to be available to school personnel other than teachers of science who might also be using chemicals. These personnel could include teachers of art, manual arts, agriculture, janitor/grounds -care personnel, teacher aides, scientific assistants and other classroom visitors.

3.3.1

LABELS

Labels are required to identify the hazards associated with the substance. Labels should be checked when substances arrive to see that they have the following information: • signal word(s), dangerous goods class and subsidiary risk labels as applicable; • identification information; • risk phrases; • directions for use; • safety phrases; • first-aid procedures; • emergency procedures; • details of the manufacturer/supplier; • expiry date if relevant; • reference to the MSDS. If a substance is transferred to a new container, then it must be labelled with the following: • the product name; • the risk phrases; • the safety phrases.

3.3.2

LABELLING OF SMALL CONTAINERS

Often in science, and in other subjects, chemicals are transferred into small (60mL or 100mL) containers for student use, and there may not be sufficient room for full label information. In this case, the full label may be attached to a supporting device kept with the containers. For example, in the case of a test tube, the label may be attached to the test tube rack. Alternatively, a tag with the required information may also be used (Code of Practice for the Management of Hazardous Substances at Work 1995).

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3.4

CHEMICAL NOMENCLATURE Standard name

Synonym(s)

acetylcholine chloride

acecoline, arterocoline

acetyl-2-hydroxybenzoic acid

acetyl salicylic acid, aspirin

adenosine-5-diphosphate

ADP, adenosine-5-diphosphate (sodium salt)

adenosine-5-monophosphate

AMP, adenosine-5-monophosphate (sodium salt)

adenosine-5-triphosphate

ATP, adenosine-5-triphosphate (sodium salt)

agar, nutrient

nutrient agar, nutrient, tablets

agar, powder

agar technical, agar agar, isinglass (ambiguous), macassar gum

alizarin red

sodium alizarin sulfonate

aluminium ammonium sulfate(VI)-12-water

ammonium alum

aluminium oxide

alumina, corundum, diamantine

aluminium potassium sulfate(VI)-12-water

alum, alum potash, potash alum, potassium alum, potassium aluminium sulfate

4-aminobenzenesulfonic acid

p -aminobenzenesulfonic acid, para-aminobenzenesulfonic acid, sulfanilic acid, sulfonilic acid

aminoethanoic acid

amino-acetic acid, glycine

2-aminopentanedioic acid

aspartic acid, glutamic acid, L-aspartic acid, L-glutamic acid

ammonium carbonate

crystal ammonia

ammonium chloride

sal ammoniac

diammonium copper (II) sulfate (VI)-6-water

ammonium cupric sulfate

ammonium dichromate (VI)

ammonium bichromate

ammonium dihydrogen phosphate (V)

ammonium biphosphate, monobasic ammonium phosphate

ammonium ethanedioate-1-water

ammonium oxalate

ammonium iron (III) sulfate (VI)-l2-water

ferric alum, iron alum

ammonium molybdate (VI) 4--water

ammonium paramolybdate

triammonium phosphate (V)-3-water

ammonium phosphate

ammonium polytrioxovanadate (V)

ammonium metavanadate, ammonium vanadate

ammonium sodium hydrogen phosphate (V)-4-water

microcosmic salt

aniline blue

china blue, cotton blue, water blue

antimony

stibium

antimony (II) chloride

antimony trichloride

antimony (V) chloride

antimony pentachloride

antimony (III) oxide

antimony trioxide, senarmonite, velentinite

aqueous ammonia

ammonia solution, ammonium hydroxide, spirits of hartshorn

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ASPECTS OF SCIENCE M ANAGEMENT Standard name

Synonym(s)

aqueous ammonia, 35%

ammonia, SG 880, 880 ammonia, liquor ammonia fort, liquor fort

arsenic (III) oxide

arsenic trioxide, arsenious acid, arsenious oxide, arsenous oxide, white arsenic

asbestos, fibre

mineral wool

asbestos, 5% platinised

platinised asbestos

L-ascorbic acid

vitamin C

barium carbonate

witherite

barium sulfate (VI)

heavy spar

benzene

benzol

benzene-1,2-dicarboxylic acid

phthallic acid

benzene-1,2-dicarboxylic anhydride

phthallic anhydride

benzene-1,3-diol resorcinol

1,3-dihydroxybenzene

benzene-1,4-diol

1,4-dihydroxybenzene, hydroquinone, quinol

benzene-1,2,3-triol

1,2,3-trihydroxybenzene, pyrogallic acid, pyrogallol

benzene-1,3,5-triol

phloroglucinol, phloroglucinol solution (5% in ethanol), 1,3,5-trihydroxybenzene

benzoic acid

benzene carboxylic acid, phenylformic acid

benzoyl peroxide

di (benz oyl) peroxide

benzyl benzoate

phenylmethylbenzoate

bismuth carbonate dioxide

bismuth carbonate, bismuth oxycarbonate, bismuth subcarbonate, bismuthyl carbonate

bismuth chloride

bismuth trichloride

bismuth chloride oxide

bismuthyl chloride

ismuth oxide

bismite, bismuth ochre

bleaching powder

basic calcium chloride, calcium hypochlorite, basic calcium hypochlorite, calcium oxychloride, chloride of lime, chlorinated lime

4-bromoacetanilide

p -bromoacetanilide, para-bromoacetanilide

1-bromobutane

n-butyl bromide

2-bromobutane

s-butyl bromidesec-butyl bromide, secondary butyl bromide

bromocresol green

bromcresol blue, bromcresol green, bromocresol blue

bromocresol purple

bromcresol purple

1.2-di bromoethane

ethylene dibromide

2-bromo-2-methylbutane

t-butyl bromide, tert -butyl bromide, tertiary butyl bromide

bromophenol blue

bromphenol blue

butanoic acid

butyric acid, n-butyric acid, ethylacetic acid, normal butyric acid

butanedioic acid

succinic acid

81

ASPECTS OF SCIENCE M ANAGEMENT Standard name

Synonym(s)

butan-1-ol

1-butanol, n-butanol, n-butyl alcohol, normal butanol, normal butyl alcohol, normal propyl carbinol, n-propyl carbinol

butan-2-ol

bu-butanol, s-butanol, s-butyl alcohol, methyl, ethyl carbinol, sec-butanol, sec-butyl alcohol, secondary butanol, secondary butyl alcohol

butanone

ethyl methyl ketone, methyl ethyl ketone

cis butenedioic acid

maleic acid

calcium carbonate

aragonite, calcite, calc spar, carbonate of lime, chalk, iceland spar, limestone, marblewhiting

calcium carbonate (marble chips)

marble chips

calcium chlorate (I)

bleaching powder (with = commercial grade) calcium hypochlorite

calcium dicarbide

acetylenogen, calcium carbide

calcium fluoride

blue john, Derbyshire spar, fluorite, fluorspar

calcium hydride

hydrolith

calcium hydroxide (solution)

limewater, slaked lime

calcium nitrate (V)-4-water

Norwegian saltpetre, saltpetre Norwegian

calcium oxide

lime quicklime

calcium sulfate (VI)

anhydrite

calcium sulfate (VI), commercial

plaster of paris

calcium sulfate (VI)-2-water

alabaster, gypsum, selenite

calcium tetrahydrogen phosphate (V)

calcium hydrogen orthophosphate, calcium hydrogen phosphate, calcium orthophosphate, calcium phosphate, monobasic calcium phosphate, monocalcium phosphate, sec - calcium phosphate, secondary calcium phosphate

Canada balsam

balsam of fir, Canada turpentine

carbon, powdered

charcoal powder

carbon disulfide

carbon bisulfide

cellulose ethanoate

cellulose acetate

cerium (III) sulfate (VI)

cerous sulfate

chloric (VII) acid

perchloric acid

1,4-di chlorobenzene

p -dichlorobenzene, paradichlorobenzene, paramoth

1,2-di chloroethane

ethylene dichloride

2.2,2-tri chloroethane diol

chloral hydrate

chloroethanoic acid

chloroacetic acid, monochloroacetic acid

trichloroethanoic acid

trichloroacetic acid

tetra chloromethane

carbon tetrachloride, perchloromethane

trichloromethane

Chloroform

(chloromethyl) benzene

alpha-chlorotoluene, benzyl chloride, a-chlorotoluene

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Synonym(s)

2-chloro-2-methylpropane

t-butyl chloride, tert -butyl chloride, tertiary butyl chloride

2, 6-dichlorophenolindophenol solution

2,6-dichloroindophenol, DCPI P

hexachloroplatinic (IV) acid

platinic chloride

chromium (III) oxide

chromium sesquioxide

chromium (VI) oxide

chromic acid, chromic anhydride, chromium trioxide

chromium (III) potassium sulfate (VI)-12 water

chrome alum

citric acid, hydrated

2-hydroxy-1,2,3-propane tricarboxylic acid 2-hydroxypropane-1,2,3-tricarboxylic acid

clove oil

oil of cloves

cobalt (II) chloride-6-water

cobaltous chloride

coconut oil

copra oil

copper (II) carbonate (basic)

basic copper carbonate, copper carbonate hydroxide

copper (I) oxide

cuprite, red oxide of copper, ruby copper

copper (II) oxide

melaconite, tenorite

copper (II) sulfate(VI)-5-water

bluestone, blue vitriol, chalcanthite, copper vitriol, cyanosite

copper (II) sulfide 6

covelline, covellite

crystal violet

gentian, gentian violet hexamethyl-p-rosaniline chloride, methyl violet

cyclohexane

hexahydrobenzene

cyclohexanol

hexahydrophenol, hexalin

cyclohexene

3, 4, 5, 6-tetra hydrobenzene

decanedioyl dichloride

sebacoyl chloride

dodecanoic acid

lauric acid

dodecan-1-ol

lauryl alcohol

di(dodecanoyl) peroxide

lauroyl peroxide

DPX

depex

EDTA

ethylene diamine tetracetic acid

EDTA, disodium salt

disodium ethylene diamine

eldon cards

blood grouping cards

eosin

bromoeosin, sodium-2,4,5,7-tetrabromofluorescein

ethanal

acetaldehyde

ethanal tetramer

metaldehyde

ethanamide

acetamide

ethanedioic acid-2-water

oxalic acid

ethanoic anhydride

acetic anhydride

ethane-1,2-diol

ethane diol

ethanoic acid

acetic acid, vinegar acid

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Synonym(s)

ethanoic acid, glacial

acetic acid, glacial

ethanol

absolute alcohol (at 100%) alcohol (ambiguous) ethyl alcohol, methyl carbinol

ethanol,95%

rectified spirits

ethanol. denatured

alcohol denatured, denatured alcohol, denatured spirits

ethanol. methylated

methylated spirits, spirit vini meth

ethoxyethane

diethyl ether, ether, ethyl oxide, sulfuric ether

ethyl carbamate

urethane

formalin

(solution) formaldehyde, (solution) methanal

French chalk

talc, powder

gelatine

gelatin, puragel

(+)glucose

blood sugar, dextrose, dextrose monohydrate, glucose, D-glucose, grape sugar, monohydrate

graphite

carbon, graphite

graphite. colloidal

aquadag, oildag, plumbago

gum acacla

acacia, gum arabic

haematoxylin

hydroxybrasilin

haematoxylin, Delafield's.

Delafield's haemaloxylin

hexadecan-1-ol

cetyl alcohol

hexane

n-hexane, normal hexane

hexane-1,6-diamine

1,6-diaminohexane, hexamethylene diamine

hexanedioic acid

adipic acid

hexanedioyl dichloride

adipyl chloride

hydrochloric acid

hydrogen chloride solution, muriatic acid, raw spirits, spirits of salts, spiritus salis

hydrogen peroxide

hydrogen oxide, perhydrol (=30% or 100 vol.)

2-hydroxybenzoic acid

o-hydroxybenzoic acid, orthohydroxybenzoic acid, salicylic acid

2-hydroxybutanedioic acid

malic acid

2-hydroxypropanoic acid

lactic acid

indigo carmine

sodium indigotin, disulfonate soluble indigo blue

indol-3-ethanoic acid

acetic acid indol, heteroauxin, 3-indolylacetic acid, indol-3-yl-acetic acid

iodoethane

ethyl iodide

iron, powder

ferrum redactum

iron (II) ammonium sulfate (VI)

Mohr's salt

iron (II) diiron (III) oxide

ferrosic oxide, ferrosoferric oxide, magnetic oxide

iron (III) oxide

ferric sesquioxide, jeweller's rouge, red ochre, venetian red

84

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Synonym(s)

iron (II) sulfate (VI)-7-water

green vitriol

iron (II) sulfide

pyrites

lanolin

wool fat, anhydrous

lead (II) carbonate

ceruse, cerussite

dilead (II) lead (lV) oxide

minium, red lead, red lead oxide, oxide of lead, trileadtetroxide

lead (II) oxide

lead monoxide, lithage, massicott

lead (IV) oxid e

lead dioxide, lead peroxide (misnomer)

litmus, granulated

lacmus, tournesol

L-lysine hydrochloride

lysine monohydrochloride

magnesium, ribbon

magnesium wire

magnesium carbonate

magnesite

magnesium hydroxide

brucite

magnesium oxide

magnesia, native magnesia, periclase

magnesium sulfate (VI)-7-water

kieserite

magnesium (IV) oxide

magnesium dioxide, pyrolucite

magnesium sulfate (VI)-7-water

epsomite, epsom salts

manganese (IV) oxide

manganese dioxide

mercury

quicksilver

dimercury (I) chloride

calomel, horn quicksilver

mercury (II) chloride

corrosive sublimate, mercury bichloride

methanol

carbinol, methyl alcohol

methyl benzene

toluene, toluol

1,4-di methyl benzene

p -xylene, xylol

methylbenzene-4-sulfonamide

4-methylbenzenesulfonamide, toluene-p-sulfonamide

3-methylbutan-l-ol

isoamyl alcohol

3-methylbutylethanoate

isoamylacetate

methyl cellulose

methocel

methylene blue

3,9-bisdimethylaminophenazothionium, chloride, methylthionine chloride

methyl-2-hydroxybenzoate

methyl salicylate, oil of wintergreen

methylmethanoate

methyl formate

methyl-2-methylpropanoate

methyl methacrylate

methyl orange

helianthin-B, orange III, sodium-4dimethylaminoazobenzene-4-sulfonate

4-methylphenol

p -cresol, paracresol

2-methylpropanoic acid

isobutyric acid

2-methylpropan-1-ol

isobutanol, isobutyl alcohol, isopropyl carbinol

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Synonym(s)

2-methyl-1-propanol 2-methylpropan-2-ol

t-butanol, t-butyl alcohol

tert -butanol

tert -butyl alcohol, tertiary butanol, tertiary butyl alcohol, trimethylcarbinol

methyl violet

pentamethylbenzyl-p -rosaline hydrochloride

naphthalene flakes

naphthalene

naphthalene, marbles

moth balls, naphthene

naphthalen-1-ol

alpha-naphthol, 1-naphthol, a-naphtho

naphthalen-2-ol

beta-naphthol, 2-naphthol, b-naphthol

neutral red

amino dimethyl amino toluminozine, toluylene red

nickel (II) carbonate (basic)

basic nickel carbonate

ninhydrin

indanetrione hydrate, indane-1,2,3-trione-2-hydrate, triketohydrindenehydrate, 1,2,3-triketohydrindine, monohydrate

nitric (V) acid

aqua fortis, nitric acid, spirits of nitre

nitrobenzene

oil of mirhan

2, 4, 6-trinitrophenol

picric acid

octadecanoic acid

stearic acid

cisoctadec-9-enoic-acid

cis-9-octadecenoic acid, oleic acid red oil

1-octanol

octyl alcohol, n-octyl alcohol

orange IV

C.l. acid orange, tropaeolin 00

orcein

orcin

orcein. ethanoic

acetic, aceto orcein, la cour, orcein acetic

orcein, synthetic

Gurr's synthetic orcein

orcinol

3,5-dihydroxytoluene, 5-methyl resorcinol

paraffin, hard

paraffin wax

paraffin, liquid

medicinal paraffin, paraffin oil, petrolatum liquid

pentan-1-ol

amyl alcohol, n-amyl alcohol, butyl carbinol, normal amyl alcohol, normal pentyl alcohol, pentanol (ambiguous), 1-pentanol, n-pentanol, n-pentyl alcohol

pentose

d-xylose

pentyl ethanoate

n-amyl acetate, normal amyl acetate, pentyl acetate

petroleum ether

benzine, petroleum benzin, petroleum solvent

petroleum jelly

white petrolatum, technical vaseline, white

phenol

carbolic acid

phenol fuchsin

carbol fuchsin

phenolphthalein

3,3-bis~p-hydroxyphenyl phthalide

phenylamine

aniline

phenylammonium chloride

aniline hydrochloride

86

ASPECTS OF SCIENCE M ANAGEMENT Standard name

Synonym(s)

n-phenylethanamide

acetanilide, n-phenylacetanilide

phenylethene, monomer

styrene

phenyl-2-hydroxybenzoate

phenyl salicylate salol

diphenylmethanone

benzophenone

phenylmethylbenzoate

benzyl benzoate

3-phenylpropenoic acid

cinnamic acid

phenylthiourea

phenylthiocarbamide, PTC, PTU

phosphinic

hypophosphorus acid, phosphorus acid

phosphoric (V) acid

orthophosphoric acid

phosphorus, red

phosphorus, brown

phosphorus, white

phosphorus, white

phosphorus pentachloride

phosphorus (V) chloride

phosphorus (V) oxide

phosphorus pentoxide

phosphorus trichloride

phosphorus (III) chloride

potassium carbonate

pearl ash

potassium chlorate (VII)

potassium perchlorate

potassium chloride

sylvinesylvite

potassium citrate

potassium-2-hydroxypropane-1,2,3- tricarboxylate

potassium dihydrogen phosphate (V)

monobasic potassium phosphate potassium dihydrogen orthophosphate

potassium disulfate

potassium metabisulfite

potassium ethanedioate-1-water

potassium oxalate

potassium hexacyanoferrate (II)-3-water

potassium ferrocyanide

potassium hexacyanoferrate (III)

potasslum ferricyanide

potassium (+) hydrogen 2,3-

potassium hydrogen tartrate dihydroxybuta nedioate

potassium hydrogen ethanedioate

potassium hydrogen oxalate

dipotassium hydrogen phosphate (V)

dibasic potassium phosphate, dipotassium hydrogen orthophosphate, dipotassium monohydrogen phosphate

potassium hydroxide

caustic potash

potassium iodate (V)

potassium iodate

potassium iodate (VII)

potassium periodate

potassium manganate (VII)

Condy’s crystals, potassium permanganate

potassium nitrate (III)

potassium nitrite

potassium nitrate (V)

nitrate of potash, nitre, potassium nitrate, saltpetre

potassium sodium tartrate

potassium sodium-2,,3-dihydroxybutanedioate-4-water, rochelle salt, sodium potassium tartrate, Seignette salt

potassium sulfide

liver of sulfur

propanal

propionaldehyde

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ASPECTS OF SCIENCE M ANAGEMENT Standard name

Synonym(s)

propane-1,2,3-triol

glycerin, glycerine glycerol, trihydroxypropane 1,2,3-propanetriol

propanoic acid

propionic acid

propan -1-ol

ethyl carbinol, normal propanol, normal propyl alcohol, normal propyl carbinol, primary propanol, primary propyl alcohol, propanol (ambiguous), 1-propanol, n-propanol, p propanol, n-propyl alcohol, p-propyl alcohol, n-propyl carbinol

propan -2-ol

ISO propyl alcohol

propanone

acetone, dimethyl ketone

propenamide

acrylamide

propenoic acid

acrylic acid

rennin

rennet powder, rennet tablets

resin, ion exchange

anion exchange resin

Ringer’s solution, tablets

isotonic saline (when correctly mixed) saline isotonic (when correctly mixed)

saffranin

3,7-diamino-5-phenylphenazonium chloride

silica gel

silica acid

silver chloride

cerargyrite, horn silver, kerargyrite

sodium

natrium

sodium bicarbonate

soda ash

sodium carbonate-10 water

natron, washing soda

sodium chlorate (I)

sodium hypochlorite

sodium chloride

(solution) brine, common salt, halite, (0.9% w/v solution) normal rock salt, (solution) saline, ‘sea salt’

sodium citrateate

trisodium citrate, trisodium-2-hydroxypropane-1,2,3-tricarboxyl

sodium dihydrogen phosphate (V)-2-water

monobasic sodium phosphate

sodium disulfate (lV)

sodium metabisulfite, sodium Pyrosulphate

sodium dithionite

sodium hydrosulfite

sodium ethanedioate tetra

sodium oxalate

sodium heptaoxodiphosphate

sodium pyrophosphate

sodium hexanitrocobaltate (III)

Macallum's stain, sodium cobaltinitrite

sodium hydrogen carbonate

baking soda, bicarbonate of soda bicarb. soda, sodium bicarbonate

disodium hydrogen phosphate (V)-12-water

dibasic sodium phosphate, disodium hydrogen orthophosphate, sodium monohydrogen phosphate

sodium hydrogen sulfate (VI)

nitre cake, sodium hydrogen sulfate

sodium hydroxide

caustic soda

sodium 2-hydroxybenzoate

sodium salicylate

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Synonym(s)

sodium iodate (VII)

sodium periodate

sodium lauryl sulfate (VI)

sodium dodecyl sulphate

sodium nitrate (III)

sodium nitrite

sodium nitrate (V)

chile saltpetre, nitrate of soda, nitratine, saltpetre, chile soda nitre, sodium nitrate

sodium peroxodisulfate (VI)

sodium persulfate

trisodium phosphate (V)-12-water

tripsa

sodium phosphinate

sodium hypophosphite

sodium silicate (lV)

soluble glass, water glass

sodium sulfate (VI)

Glauber’s salt, sodium sulfate, thenardite

sodium sulfate (VI)-10-water

Glauber’s salt, mirabilite, salt cake

sodium tauroglycocholate

bile salts, sodium taurocholate

disodium tetraborate (III)-10-water

borax, sodium biborate, sodium borate, sodium tetraborate,

sodium thiosulfate (VI)-5-water

hypo

strontium carbonate

strontianite

sucrose

cane sugar, sugar, cane

sudan III

red oil (ambiguous, see alphabetical synonym list), tetrazobenzin-p-naphthol

sudan IV scarlet R sulfur, flowers

sulfur, sublimed

sulfuric (VI)

acid brown oil of (78%), chamber acid (62-70%), oil of vitriol, oleum (fuming sulfuric (VI) acid), sulfuric acid

tartaric

(+)2,3-dihydroxybutanedioic acid, racemic acid

test-tape, glucose

tes-tap

thymol

1-methyl-, 3-hydroxy -, 4-isopropylbenzene

tin (II) chloride-2-water

tin salt

tin (lV) oxide

cassiterite, tinstone

triodomethane

iodoform

trioxoboric (III) acid

boracic acid, boric acid, orthoboric acid

tris -2-hydroxyethylamine

tris (hydroxymethyl) aminomethane, triethanolamine, tris buffer

turpentine, pure

turpentine, vegetable, wood turpentine

DL-tyrosine

L-tyrosine

urea

carbamide, cabinyldiamide, carbonyldiamide

vanadium (V) oxide

vanadium pentoxide

xanthodrol solution

9-hydroxyxanthene, xanthanol

D-xylose

pentose

zephiran

alkydi-methylbenzylammoniumchloride, benz-alkonium chloride

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ASPECTS OF SCIENCE M ANAGEMENT Standard name

Synonym(s)

zinc carbonate

calomine, smithsonite

zinc chloride

(solution) killed spirits

zinc oxide

flowers of zinc, philosopher's wool, red oxide of zinc, spartalite, zincite, zinc white

zinc sulfate(VI)-7-water

gosla rite, white vitriol, zinc sulfate

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4.

ELECTRICAL HAZARDS

4.1

ELECTRIC SHOCK

4.1.1

EFFECTS OF ELECTRIC CURRENT PASSING THROUGH THE HUMAN BODY

• • • • • •

Breathing can stop. The heart can stop. Burns to the skin and internal organs. Muscle spasm. Clinical shock (a reaction of the body’s nervous system to severe injury). Falls may cause injuries.

The danger to persons caused by an electric current passing through the human body depends upon the value of the current. However, it is difficult to calculate what this current will be under any given set of circumstances. The relationship of current to voltage is not linear because body resistance varies with the touch voltage and with the path taken by the current. The curves in Figure 1 represent the time current zones for AC 50/60Hz based on the assumption of the following conditions: (a) persons are of at least 50kg mass; and (b) the pathway of the current is through the extremities, hand to hand, foot to foot. It should be noted that the current axis is graduated in milliamperes and the time axis in milliseconds.

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In Zone 1, no reaction is to be expected. In fact, the subject is usually unaware of the passage of the current through the body. In Zone 2, reaction may occur, but usually no pathophysiologically dangerous effects would be expected. The person is aware of the shock and painful muscular contractions are likely to be experienced at the high side of the zone. In Zone 3, usually no risk of ventricular fibrillation exists, whereas in Zone 4, such a risk does exist. Finally, in Zone 5, the onset of ventricular fibrillation is probable. Further, it should be noted that for longer durations of the current flow in the case of Zone 3 and above there is a risk of asphyxia (inability to breathe). The ‘fibrillation’ mentioned is an abnormal condition of the heart where the normal rhythmic expansions and contractions of the heart muscles are disturbed and, instead, a disordered quivering of the muscles takes place. The heart is not capable of pumping in this condition and, unless it is corrected within a few minutes, death will result. Fibrillation is reversible only by the use of a defibrillator: there is no known mechanical cure.

4.1.2

‘LET-GO’ CURRENT (Sometimes called the ‘cannot let-go’ current)

This is defined as the maximum current a person can tolerate when holding an electrode and still let go of this electrode using muscles directly stimulated by this current. Experimental evidence places the value of this current at approximately 10 milliamperes. Higher currents would cause muscle freezing, preventing the person from releasing his/her hand from the conductor.

4.1.3

CAUSES OF ELECTRIC CURRENT PASSING THROUGH THE HUMAN BODY

Because of the complexity of attempting to predetermine the value of the current passing through the body under given conditions and the uncertainty of its effects on a particular person, precautions should be taken to ensure that contact, accidental or otherwise, with a live conductor is prevented at all times. An electric shock could be received from: (a) wall or bench outlets (power points); (b) switches; (c) mains-operated equipment; (d) leads connecting equipment to power points; (e) extension leads. In Queensland, the electricity reticulation system is MEN (Multiple Earth Neutral), i.e. the neutral wire is earthed at the powerhouse, at the point of supply to each consumer and at other points along the line between powerhouse and consumer. The diagram below schematically represents the effect of a person coming into contact with a live conductor connected to the mains, e.g. the active pin in a power point or switch or an exposed active wire in a lead.

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Experimental results indicate that, for a touch voltage of 240 volts AC, the body resistance between its extremities is of the order of 1000 ohms. Under these conditions the current flowing through the person would be 240 milliamperes. Figure 1 indicates that this current could produce serious results. The diagrams below show the effect of a broken or faulty earth wire in a lead, appliance or piece of equipment.

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In (a) the equipment is effectively insulated from its case or frame and no earth current can flow through the operator. In (b) the case or frame has become ‘live’ because of contact with the active wire. Earth leakage current can flow through two paths as shown. Because of the low resistance of the earthing wire and lead (approximately 2 ohms) the bulk of the earth leakage current (as much as 120 amperes) will flow along this path and blow a fuse, and the effects on the operator will be minimal. In (c) and (d) the earth lead is faulty or broken (i.e. high resistance), therefore the greater part of the earth leakage current will flow through the operator. The fuse will not blow because the current is insufficiently high and the effect on the operator could be fatal.

4.2.

SAFE PRACTICES AND PROCEDURES

4.2.1

POWER POINTS AND SWITCHES

(a) (b)

(c) (d) (e) (f) (g) (h)

4.2.2

Dry hands thoroughly before operating any switch. Do not allow the cover plates of power points or switches to be removed. If, for any reason, the cover plate has been removed or damaged, do not allow the point or switch to be used until it has been repaired by a qualified electrician. Switches must be in the ‘off’ position before inserting plugs or removing plugs from power points. Grasp the plug, not the lead, when removing plugs from power points. Hold the plug firmly and pull away. Do not allow students to tamper with power points or switches, e.g. by pushing metal objects into power points or poking at pilot lights with metal objects. If a power point or switch is faulty in any way, do not attempt to repair it yourself. Do not allow students to use it until it is repaired. Cover power points with plug protectors when not in use. Hand-held equipment (e.g. electric drills), unless double insulated, must be operated through an isolating transformer or a core balance earth leakage device. These are designed to protect the operator from injury in the event of faulty earth connections.

MAINS OPERATED EQUIPMENT

Mains operated equipment has to meet the stringent requirements laid down by the Queensland Electricity Industry (QEI), e.g. that it be effectively earthed (unless double insulated), and that the lead from the equipment to the power point be effectively anchored within the equipment so that it cannot be pulled loose. (a)

(b) (c) (d) (e)

If the equipment installed by the Department of Public Works and Housing, e.g. hot water systems, stills, fans, refrigerators, reticulated DC supplies, etc. fails to function, teachers should not attempt to repair it. This is not only dangerous but illegal. Faults should be reported to the nearest depot of the Department of Public Works and Housing or the principal may arrange for a local electrician to effect repairs. Avoid using 240 volt equipment near sinks or water outlets or close to gas outlets where accidental sparking may ignite gas leaks. Disconnect portable appliances from the power outlet when not in use. Before attempting to clean any mains operated equipment (portable or fixed) ensure that it is switched off and disconnected from the power point. Hand held equipment, eg. electric drills, unless double insulated, must be operated through an isolating transformer or a core balance earth leakage device. These are designed to protect the operator from injury in the event of faulty earth connections. 94

ASPECTS OF SCIENCE M ANAGEMENT

4.2.3

LEADS

Most mains-operated equipment is connected to power points through leads which contain three wires. These are colour coded as follows: Live Neutral Earth

Current Australian Standard Red Black Green

International Standard Brown Blue Green/yellow

Both these standards are presently acceptable to the Queensland Electricity Industry. The earth lead (green or green/yellow) is meant to earth the frame or metal case of the equipment to prevent shock to the user should a short circuit occur between the electrically ‘live’ parts of the equipment and the frame or case. The other two wires in the lead (red and black or brown and blue), carry the electric current operating the equipment. The following safe practices should be followed: (a) (b) (c) (d) (e) (f) (g) (h) (i)

4.2.4

Inspect all leads and fittings regularly for frayed or cracked insulation. If a lead is considered defective, it should be checked by a qualified electrician. Never use a lead if the plug which fits into the mains-operated equipment or the three-pin plug which fits into the power point are damaged or loose. Never twist or knot a lead or bend it sharply. Never tack leads to walls. Store leads when not in use in such a way that the insulation will not be damaged. Avoid using extension leads, where possible. If necessary, use commercially available leads. Home-made leads must not be used. Always switch off the equipment before attempting to disconnect extension leads. Use the shortest possible continuous lead. Use a powerboard when several appliances need to be plugged in.

ELECTRICAL INSPECTIONS

Checks are usually arranged through the principal All movable electrical equipment which has a lead fitted or which requires a lead to be attached, and all extension leads, are to be checked at prescribed intervals and tagged by a qualified electrical worker in accordance with Australian Standard AS 3760-1990 ‘In-service inspection and testing of electrical equipment’. It should be noted that damage may be caused to specialised electronic equipment such as photocopiers, computers, typewriters and facsimile machines if they are not tested correctly.

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The following table outlines the testing requirements: Intervals between inspection and test Class of equipment Type of environment where equipment is used

Class I (Earthed) TV, Stereo

Manual Arts, Cleaning, Home Economics, Tuck Shop, Ag. Science, Industrial (EdMart) etc. Science Department Staff Rooms etc.

Additional tests for portable Safety Switches Interval for push-button test by user

Interval for performance testing

6 months

Class II (Double Insulated) hair dryer, elec. drill, shaver 12 months

Daily

12 months

12 months

12 months

Daily

5 years

Records are required for all items of electrical equipment, including the dates of each test, and the name and licence number of the qualified electrical worker, to be kept and to be made readily available to a Division of Accident Prevention inspector upon request.

4.2.5

REPORTING AN ACCIDENT

See the DOEM activity module HS-08: Accident and/or Incidents  Reporting and Investigation. In addition, any accident involving mains power should be reported to the local electrical authority, which will conduct an investigation and report to the QEI. Such action may prevent further accidents from similar causes.

4.2.6

ISOLATING TRANSFORMERS

As the name suggests, this device isolates the mains from the equipment being operated. It consists of a 1:1 transformer contained in a case. The insulation between the primary circuit (connected to the mains) and the secondary (connected to the equipment) is required to be at least 100 megaohms. The case (if not metal) is not earthed and the earth pin of the outlet socket on the isolating transformer, i.e. the socket to which the equipment is connected by a three-pin plug, is not connected to earth. Should the frame or case of the equipment become ‘live’ due to contact with a current-carrying wire, no current will flow to earth through the person holding or touching the equipment. A diagram of the arrangement (not to scale) is shown below:

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4.2.7 PRECAUTIONS TO TAKE WHEN USING AN ISOLATING TRANSFORMER (a) (b)

4.2.8

Do not attempt to attach earth leads anywhere in the circuit. If the unit fails to deliver current to the equipment or appears faulty in any way, do not attempt repairs. Call in a qualified electrician.

CORE BALANCE EARTH LEAKAGE DEVICES

The devices work on the principle of current balance. In any electrical equipment which is in good condition, the currents in the active and neutral conductors are equal and opposite. A current transformer placed around these two conductors will have no secondary voltage induced or current flowing. If the equipment is earthed and the insulation resistance between equipment and the earth is low, some of the load current will flow to earth instead of returning through the neutral (earth leakage current). Since only the active and neutral conductors pass through the current transformer, the currents in these two conductors are no longer balanced and do not cancel. This out-of-balance earth leakage current induces a voltage in the secondary of the current transformer which is used to operate a relay and trip a circuit breaker. The operation of the device is represented in the following diagram:

If, for any reason, an earth leakage current flows through the operator, as shown in the diagram, the imbalance between the currents in the active and neutral leads causes a current to flow in the circuit of the secondary of the current transformer which operates a relay and a circuit breaker, thus switching off the mains. Notice that the mains system is MEN (Multiple Earth Neutral), as stated previously. This protective system does not prevent current passing through the operator, but design considerations can keep this current low in value and flowing only for a limited time, i.e. until the circuit breaker operates. Portable devices of this kind operate on an earth current of 20 milliamps and tripping times as low as 30 milliseconds. Reference to Figure 1, at the beginning of this section, will show that this combination of 97

ASPECTS OF SCIENCE M ANAGEMENT

current and time lies in Zone 2, where the operator will be aware of the shock but will experience no dangerous effects. All these devices have reset buttons which must be operated after the circuit breaker has been tripped. Test buttons are also provided to enable the operator to ascertain whether the device is working according to the design specifications. Most high schools have a device of this kind protecting the electric circuits in the laboratories and demonstration rooms.

4.2.9

LEGISLATION AFFECTING ELECTRICAL SAFETY

A number of changes have been made to the legislation, namely Workplace Health and Safety Amendment Regulation (No. 1) 1996 (SL 142 (1996)) and Amendment Regulation (No. 6) 1996 (SL 427 (1996)), which amend certain requirements for the inspection, testing and protection of electrical equipment. By mid-1997, it is expected that there will also be a Compliance/Advisory Standard issued to address issues and requirements affecting electrical safety. Section 76 of the Regulation sets out these requirements for all electrical equipment used within a school workshop. All such equipment must be regularly tested and inspected, and portable equipment be double insulated or connected to an appropriate safety switch, isolating transformer, or earthmonitoring device in accordance with Australian Standard AS 3760 (1990). There are minimum periods specified for the checking of test buttons of safety switches or isolators both by employer and by an electrical worker. Section 75 applies to most other school situations and gives a choice of testing/tagging or use of safety switches as a prescribed form of protection. Checking of such safety switches by the employer is still necessary at monthly intervals. The yearly check by an electrical worker is also recommended. Section 82 refers to the testing and using of safety switches. Some of the relevant requirements are: In school workshops, all electrical equipment must be regularly tested and inspected, and portable equipment be double insulated or connected to an appropriate safety switch, isolating transformer, or earth-monitoring device. In school workshops the test button of all safety switches, such as core balance earth leakage devices, must be operated as soon as they are connected to a socket outlet. Thereafter, they must be checked before they are used for the first time on each day of use. These devices must be checked by an electrical worker at not more than one-yearly intervals. In most other locations throughout the school, the test button of any fixed safety switches must be operated at least monthly to ensure the device is operating satisfactorily. At least once every two years, an electrical worker must also check the device.

4.2.10 MANAGEMENT OF ELECTRIC SHOCK VICTIMS The rescuer must: • • •

Turn off the electricity supply if possible. OR Disconnect the victim from the electricity supply by the use of a dry non-conducting material e.g. dry clothing, a wooden stick. Avoid any direct contact with the skin of the patient or any conducting material touching until disconnected. 98

ASPECTS OF SCIENCE M ANAGEMENT

• •

4.3

Commence resuscitation. Use cardiopulmonary resuscitation if the patient’s heart has stopped beating. Seek medical help.

FURTHER ELECTRICAL DATA

Further support resources relating to aspects of safe use of electricity, such as those listed below, are available through the Queensland Electricity Industry (QEI). Brochures • • • • • • • • • • • • • •

How to improve the safety of your home for your family How to make your house a safe home Help protect your electrical equipment against lightning and voltage surge s Overhead power lines: look up and live Electricity in rural industry Portable hand tools and using them safely Electrical leads and using them safely Swimming pools and using them safely Electric blankets and using them safely Second-hand appliances and using them safely Wear those shoes  an important part of using electricity safely Electricity and using it safely Electricity and using it safely with children Switch to safety with a safety switch

Videos Electricity and using it safely (copy in all schools) Electricity and using it safely in rural industry Posters Make your house a safe home (with electrical maintenance) Take home extra protection (with a safety switch) Available from your local electricity corporation: The Capricornia Electricity Corporation (CAPELEC) The Far North Queensland Electricity Corporation (FNQEB) The Mackay Electricity Corporation (MEB) The North Queensland Electricity Corporation (NORQEB) The South East Queensland Electricity Corporation (SEQEB) The South West Power The Wide Bay−Burnett Electricity Corporation (WBBEB) Powerlink Austa Electric

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5. RADIATION HAZARDS 5.1

RADIOACTIVE SUBSTANCES

The following information has been extracted from the Code of Practice for the Safe Use of Ionizing Radiation in Secondary Schools (1986) and the Code of Practice for the Safe Use of Lasers in Secondary Schools (1995) produced by the National Health and Medical Research Council. Radioactive substances generally emit alpha or beta particles or gamma rays or combinations of these, while X-ray units generate electromagnetic waves similar to gamma rays, but usually of lower frequency (and longer wavelength). The amount and type of shielding needed depends on the penetrating power of the particular form of radiation. The denser the shielding material the better shield it will be. Alpha particles, being charged and relatively heavy atomic particles, are easily stopped, while gamma rays, usually being very short waves, are far more penetrating and hard to stop. To sum up: Alpha particles Stopped by sheet of paper or surface layers of skin. Beta particles Stopped by a few millimetres of aluminium or 1-2 centimetres of plastic. Gamma rays Almost completely stopped by about 1 metre of concrete or about 5 centimetres of lead. Most will pass through the human body. X-rays (medical) Almost completely stopped by 2-3 millimetres of lead, or about 10-15 centimetres of concrete. Will pass through the body with some absorption depending on the density of organs in the beam (e.g. skin, bones etc.). The philosophy for the control of hazards associated with the use of ionizing radiation is that: (a) no practice should be adopted unless its introduction is necessary and produces a positive net benefit; and (b) all exposure should be kept as low as possible. Ionizing radiation in schools must only be used in simple experiments to demonstrate fundamental principles. The sources used and the methods of using them must be chosen to ensure that the degree of hazard is negligible. Consideration should be given to minimising the number of experiments or demonstrations which may take place in a year. Advice in planning such experiments or demonstrations should be sought from: Division of Health and Medical Physics Queensland Health Department 535 Wickham Terrace Brisbane Q 4000 Advice for packaging, transportation and disposal of radioactive substances should be sought from: Radiation Health 450 Gregory Terrace Fortitude Valley Q 4006 The immediate responsibility for radiation safety in any experiment involving radiation rests with the teacher responsible for the class. No demonstrations or experiments requiring the exposure of students, staff or any other person to ionizing radiation shall be performed.

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5.2 (a) (b) (c)

(d)

(e)

(f)

(g)

MODES OF RADIATION EXPOSURE The possible modes of radiation exposure can be divided into two types: external or internal exposure. External irradiation results from the exposure to X-rays or to radiation from sealed or unsealed radioactive sources external to the body. The radiation dose from X-rays is dependent on: (i) operating factors of the X-ray tube (kV (peak) and mA); (ii) duration of irradiation; (iii) protective barriers between the tube and the body; (iv) distance between the tube and the body; (v) filtration of the X-rays by material in the beam; (vi) amount of scattering of the primary beam that has taken place. The radiation dose from radioactive materials external to the body is dependent on the radionuclide and: (i) the type of radiation emitted by the radioactive materials  that is, alpha particles, beta particles, gamma radiation or combinations of these, and the energy of the radiation emitted; (ii) the activity of the radioactive substance; (iii) the distance between the source and the body; (iv) the protective barrier between the source and the body; and (v) the duration of exposure to the rays. Shielding may be needed to protect staff and students (for details see section (g)). Internal irradiation results from the entry of radioactive materials into the body, with the resultant exposure of organs which have absorbed such materials and, in most cases, the exposure of other nearby organs. The amount of radioactive materials taken into the body depends on a variety of factors including: (i) the activity of the radioactive material being handled; (ii) its physical state (e.g. liquid, gas, powder, aerosol, solid); (iii) its concentration and chemical form; (iv) methods of handling and precautions taken; (v) personal hygiene; (vi) the duration of handling; and (vii) site of entry into body (e.g. skin, wound, mouth, nose etc.). The radiation dose resulting from the entry of a particular amount of radioactive material into the body depends on: (i) the type of radioactive material; (ii) the type and energy of the radiation it emits; (iii) its solubility, physical and chemical form, and effective half life; and (iv) the biological behaviour (or characteristics) of the radioactive material (e.g. some elements are selectively absorbed by certain organs of the body, such as iodine by the thyroid, and radium and strontium by bone). Shielding In school experiments involving X-rays or radioactive substances the radiation levels should be so low that no special shielding is required. However, it is important when using sources of radiation in schools to demonstrate the role of shielding as part of safe working practices.

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5.3

RADIOACTIVE SOURCES

The teacher of science must ensure that: (a) (b)

(c) (d) (e)

(f) (g) (h)

(i)

Only approved sealed radiation sources are used. (See page 301 of the Code of Practice for the Safe Use of Ionizing Radiation in Secondary Schools (1986). All radiation sources are stored in lockable metal containers (metal cash box is suitable) which are permanently labelled. If there is more than one source, then they should be stored in separate compartments within the box. This container should be kept in the school safe. Access to this container is limited to authorised members of the school staff. Sources are clearly labelled with the word radioactive, with the type and activity of the radionuclide and, for short half-life (less than 10 years) material, the year of manufacture. Ionizing radiation sources in schools are only used for simple experiments to demonstrate fundamental principles. The sources used and the method of using them must ensure that the degree of hazard is negligible. Gifts of radioactive sources, discharge tubes, operational high-voltage generators or X-ray units of any kind are not accepted. No demonstrations or experiments requiring the deliberate exposure of students, staff or any other person to ionizing radiation are performed. Routine checks of the condition of each source are carried out at intervals not exceeding 5 years. Checks must be carried out sooner following an event such as a fire or an accident which may have damaged the source. If a source of radiation is lost, or suspected of being stolen or damaged, the matter is reported, in the first instance, to the principal who shall then inform the Department of Education and the Division of Health and Medical Physics.

The immediate responsibility for radiation safety in any experiment rests with the teacher of science responsible for the class. The teacher should ensure that: (a) (b) (c) (d)

5.4

radiation sources are only handled by tongs or forceps; radiation sources are used by students only when under direct supervision; all sources of radiation are accounted for; radiation sources are clearly marked as radiation sources, and no-one stands within one metre of operating equipment.

COLD CATHODE TUBES  DISCHARGE TUBES

The following gas-discharge tubes supplied to schools fall into this category: (a) (b) (c) (d)

Discharge tube with side tube for connection to a vacuum pump. Maltese cross discharge tube. Discharge tube to illustrate the deflection of cathode rays by magnetic fields. Windmill tube.

All these tubes are operated by high voltages produced by induction coils and may produce unwanted X-rays incidental to their intended use. The voltages necessary to operate these tubes depend upon the dimensions of the tube and the pressure of the gas in the tube. Generally, the higher the voltage used, the greater the danger of the production of unwanted X-rays. The following precautions must be taken when using any one of the tubes mentioned above: (a)

The voltage applied should be kept as low as possible. The voltage from the induction coil can be varied by changing the distance of the make -and-break hammer from the iron core 102

ASPECTS OF SCIENCE M ANAGEMENT

(b) (c) (d)

5.5

of the induction coil windings. Commence with the hammer well away from the core and slowly decrease the distance between them (by means of the adjusting screw) until the tube operates. Such tubes shall be operated by the teacher of science for demonstration purposes only. The use of these tubes should be limited to as short as time as possible. All students should be kept a minimum distance of one metre and teachers should also try to observe this distance.

LASERS

SAFETY The safe use of lasers for all applications is controlled by Australian Standard AS 2211. This document, which follows international standards, sets classifications of lasers, and documents some of the safe practices for general applications. Guidelines for the safe use of lasers in the classroom have been developed by the National Health and Medical Research Council of Australia (NH&MRC) in a Code of Practice for the safe use of Lasers in Secondary Schools (1983). Copies of this code and further advice should be obtained from: The Director Division of Health and Medical Physics Department of Health 450 Gregory Terrace Brisbane Q 4000 The hazard from lasers is primarily that of burning of tissue either in the eye or, for high-power lasers, the skin. The eye is particularly at risk because the lens of the eye may concentrate the beam to a very small image on the retina, in which the energy density is extremely high. Lasers are classified according to the degree of hazard presented. This depends on the output power, the size of the beam, the irradiance at any point in the beam, the wavelength, and for a pulsed laser, the power in a single pulse and the repetition frequency. All lasers and products incorporating lasers must bear a label stating the class of the laser product, the wavelength emitted or the medium, and maximum power output. Devices above Class 1 must have additional safety markings. Class 1 lasers are intrinsically safe, i.e. they cannot cause harm, either because the exposure level which produces injury cannot be reached under any conditions, or because engineering design is such that access to dangerous levels is not possible. Class 2 lasers are low power devices which emit visible radiation. They are not intrinsically safe, although eye protection is normally afforded by aversion responses (e.g. blinking). Classes 3A, 3B and 4 are not permitted in schools. The supervision of the use of lasers throughout a school shall be the responsibility of the head of department/principal. This person shall be responsible for the buying, storage and allocation of lasers, and for ensuring that the requirements of the code are met at all times. Only Class 1 or Class 2 lasers should be used in schools.

5.5.1

CLASS 1 LASERS

Class 1 lasers require no special safety precautions other than to warn students that good practice dictates that you never shine a laser beam, regardless of its class, directly into someone's eyes. 103

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5.5.2 5.5.2.1 (a) (b)

(c) (d)

(e)

5.5.2.2 (a)

(b)

(c)

(d) (e) (f)

CLASS 2 LASERS RESPONSIBILITY Lasers must only be used under the direct supervision of a member of the science staff and should be used for demonstration purposes only. The teacher of science in charge of a demonstration shall be immediately responsible for the safety of that demonstration and he/she shall ensure that risk assessment and management are implemented. If a new demonstration is to be introduced, then a trial must be carried out, without students present, to evaluate the safety aspects of the demonstration. All persons must be instructed not to look directly into the main beam or reflected or refracted beams and students must be warned of the potential hazard and the seriousness of eye damage. Access to laser work areas should be limited and casual observers should be excluded.

SCREENS OR SHIELDS Sunglasses and welder's goggles do not provide protection from laser beams. Provided appropriate shields (i.e. shields complying with the code) are used, it is not necessary for teachers or students to wear additional protective eye wear. Shields must be used to prevent both strong reflections and the direct beam from going beyond the area needed for demonstration. Shields must be painted matt black to reduce reflection. The base material of such shields must not have a shiny surface as paint may flake exposing a mirror-like surface. Specularly reflected beams from shiny objects may be hazardous even when only a small amount of the incidental beam is reflected. Such reflections may arise from polished metal trimmings on instrument housings and from mirrors, bottles, glass lenses, watches, rings, cuff-links, polished wooden furniture, windows or any smooth surface. These articles should be removed from the vicinity of the laser or covered with matt black paper or cloth. Care must be taken to ensure that surfaces which would otherwise reflect diffusely do not become wet as this may cause specular reflection. Baffles should be placed near lenses, or other shiny objects in the beam path, to intercept oblique specularly reflected beams and oblique refracted beams. The laser head must be rigidly fixed in position so that the direction of the laser beam cannot be accidentally altered. Optical components and shields must also be firmly fixed in position. The room lighting in the laser work area should be as bright as practicable while the laser is in operation, in order to constrict the pupil diameter of the observer's eyes.

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WARNING SIGNS (1)

Each Class 2 laser must have attached to it a warning label with the following dimensions and wording.

Colour scheme: background  yellow; lettering  black. Minimum dimensions: 10.5cm x 5.2cm.

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ASPECTS OF SCIENCE M ANAGEMENT

(2)

When a Class 2 laser is in operation, warning signs must be displayed in conspicuous locations both inside and outside the demonstration area. These signs must be removed when the laser is not in use. Area warning signs must conform to the following dimensions, wording and design.

Colour scheme: background  yellow; lettering  black. Minimum dimensions: 20cm edge.

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6.

PLANT AND ANIMAL HAZARDS

6.1

BIOLOGICAL ACTIVITIES

6.1.1

TEACHER RESPONSIBILITIES

The teacher is responsible for managing a safe educational environment and ensuring that the biological activity addresses safety issues and procedures and observes regulations, requirements and protocols (e.g. blood product protocols, Material Safety Data Sheets) established by appropriate Commonwealth authorities (e.g. Australian Quarantine and Inspection Service) and state and local governments. Plant and animal hazards that may be encountered during the teaching of science include: (a) (b) (c) (d) (e) (f) (g) (h)

micro-organisms (cultures should be used under the assumption that any culture can develop dangerous growths and should be treated cautiously); animals (most animals can inflict bites and should be handled with great care); parasites (animals carry parasites which could have adverse effects on humans); plants (plants may exude substances or may have been sprayed with substances which can have an effect on humans if contact or ingestion occurs); dissection material (all material used for dissection should be treated as though it were contaminated); blood (samples should not be taken from students); equipment (all equipment should be sterile, particularly dissecting instruments); and chemicals used for euthanasia, preserving, sterilising, staining and fixing (some chemicals used for these purposes are flammable and fire safety should also be considered).

Teachers of science are reminded to refer to the hazards section in paragraphs 2.7 to 2.23 in HS-10: Workplace Health and Safety Guidelines  Curriculum in the Department of Education Manual. The risk level involved in biological activities in science may vary according to the nature of the activity and the age and experience of the client group.

6.1.2

BIOLOGICAL RISKS

The inclusion of practical work involving live animals, dissections, growing cultures and blood or blood products in teaching biology exposes teachers, scientific assistants and students to health hazards. By being aware of the risks and adhering rigorously to protective measures, the risks can be minimised. The types of risks include the following: (1) Diseases may be transferred from animals to people through bites and scratches received while handling the animals or by contact with animal materials or animal house refuse. (2) Parasites may be transferred to people through unsanitary practices. (3) Other diseases may enter the body through percutaneous inoculation, i.e. puncturing the skin with sharp objects such as dissection instruments. (4) Contamination of non-intact skin or mucosal membranes, i.e. handling biological materials when broken skin is unprotected, or splashing or touching eyes and face with contaminated hands may allow diseases to enter the body. (5) Potentially dangerous pathogenic organisms can be cultured in schools if appropriate procedures for the exposure of agar plates are not followed. (6) Appropriate storage, disposal and sterilisation procedures must be followed to minimise any risks associated with biological materials. (7) Field excursions may expose students and sta ff to potentially lethal plants and animals. 107

ASPECTS OF SCIENCE M ANAGEMENT

DISINFECTANT SOLUTIONS (1) (2)

Sodium hypochlorite is regarded as a safe and effective agent for surface disinfection. It must be prepared on the day it is to be used. Commercial laundry bleach (White King, Snow White etc.) is also suitable. A dilution with tap water of 1:10 will give a 5000ppm (0.5%) solution, a dilution of 1:100 will give a 500ppm (0.05%) solution.

6.2

CULTURES AND MICRO-ORGANISMS

6.2.1

PERSONAL PROTECTION

(1) (2) (3)

6.2.2 (1) (2)

6.2.3 (1) (2) (3)

6.2.4 (1) (2) (3) (4)

Treat all cultured organisms as potentially pathogenic and therefore a potential source of infection. Avoid contact between the hands and the mouth and other skin surfaces, e.g. touching the plate with fingers or pencils or pens, or touching an unsterilised loop. Hands must be washed before leaving the laboratory.

EXPOSURE OF AGAR PLATES Agar plates should not be exposed in situations where pathogenic organisms may exist, e.g. toilets, near persons coughing or sneezing etc. Once agar plates have been exposed or inoculated they must be taped securely closed. Do not remove the tape from plastic petri dishes and only remove the tape from glass dishes after they have been sterilised.

STERILISATION Inoculating loops should be heated to red-hot before and after use. Equipment and specimens may be sterilised by autoclaving or heating in a pressure cooker for 15 minutes. All equipment and work surfaces must be disinfected after use.

DISPOSAL Plastic petri dishes must be autoclaved or sterilised in a pressure cooker before disposal. Glass petri dishes and culture tubes must be sterilised before cleaning. Unsterilised cultures must not be disposed of down the sink. Sterilised culture wastes may be disposed of in the industrial waste bin.

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6.3

HAZARDOUS ANIMALS Organism

Venom apparatus

Symptoms

First aid

Distribution

Mammals Platypus (male only)

Horny spine attached to venom gland inside each hind leg near heel

Swelling, immediate intense pain, shock.

Wash the wound thoroughly. Seek medical attention if severe.

Coastal and some inland streams, south of Cooktown.

Echidna (male and juvenile females)

As above, but smaller

Swelling, immediate intense pain, shock.

As above

Widespread, but more common in Western Queensland

Flying foxes

Bites or penetrating scratches may cause infection of human beings with the Lyssavirus virus.

Refer to Queensland Health.

Reptiles Land and sea snakes

Venom from specialised salivary glands is delivered via ducts to hollow teeth (fangs) and the upper jaw. All dangerous snakes have fangs at the front of the mouth, although not all species which have front fangs are dangerous. Large specimens of species which have fangs at the back of the mouth should be treated with caution. Teeth other than fangs may also cause punctures so the appearance of the wound does not point to either a potentially dangerous or harmless snake.

-

Bleeding at site of bite Bruising Vomiting Sweating Drowsiness Paleness Tender and enlarged lymph nodes Loss of consciousness Passing blood in the urine. Symptoms may not appear for 2-3 hours. Many of these are also symptoms of fear when snake bite is suspected, but always let the doctor decide if it is snake bite or snake fright.

See Summary of treatments for some animals. Section 6.4.

Taipan: coastal Qld, east of Divide, and across Cape York Peninsula King Brown: throughout Qld except coastal SE Qld Death Adder: throughout Qld Tiger Snake: isolated area of SE Qld Brown Snake: throughout Qld Colletts Black Snake: confined to Central W Qld Red-bellied Black Snake: coastal Qld south of Cooktown Rough -scale Snake: coastal Qld from NSW border to Fraser Island and from Tully to Mossman Small-eyed Snake: eastern Qld south of Cairns

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A SPECTS OF S CIENCE MANAGEMENT Organism

Venom apparatus

Symptoms

First aid

Distribution

S PIDERS Red-back spider

Venom glands elaborate venom through a pair of fangs on cephalothorax

-

Severe local pain Sweating Inflammation and swelling Pain spreading Nausea and vomiting Weakness Respiratory failure

See Summary of treatments for some animals. Section 6.4.

Throughout Queensland, most common where natural environment has been disturbed

Funnel-web spider and trapdoor spiders

Venom glands elaborate venom through pair of fangs on cephalothorax

-

Intense local pain Vomiting, sweating and cramps Delirium and intense salivation Respiratory failure

See Summary of treatments for some animals. Section 6.4.

Moist cool environment in south east Queensland

While feeding on blood, ticks inject saliva into surrounding tissues. This saliva may: - Be toxic - Transfer micro-organism - Cause allergy -type reactions in hyper-sensitive people.

-

Local swelling around area of bite Severe skin irritation (itching) Necrosis of tissue in vicinity of bite Paralysis in severe cases

See Summary of treatments for some animals. Section 6.4.

Coastal areas of Queensland

Severe lesions. Severe skin irritation -scrub itch’.

Douse with alcohol.

Rainforests and wet sclerophyll forests

-

Leech will detach when touched with salt or a hot match near. Compressive bandage to control bleeding. - Insect repellent spray on shoes, clothing helps discourage bites.

Rainforests, wetter eucalypt forests

Other arthropods Ticks

Larval ticks and mites

Leeches

Three chitinous jaws make incision in skin, inject anticoagulant saliva in wound, possible transmission of micro-organisms.

Prolonged bleeding from bite Sensitisation can occur after repeated exposure to bites

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A SPECTS OF S CIENCE MANAGEMENT Organism

Venom apparatus

Symptoms

First aid

Distribution

Centipedes

Venom injected via a pair of jawlike chelicerae

Large specimens cause severe pain that may last for several days.

Apply ice a nd seek medical advice.

Throughout Queensland in forest areas

Millipedes

Some species reported to exude pungent corrosive fluid from side of body

May cause redness and swelling. Burns open wounds.

Apply ice and seek medical advice.

Throughout Queensland

Scorpions

Venom gland in terminal segment of tail

Not lethal in Australia - Local pain - Numbness - Possible collapse of victim

Apply ice. Ensure rest.

Throughout Queensland

Bees/wasps

The bee's ‘sting’ consisting of a barb and attached venom sac located on posterior. A wasp may sting repeatedly.

Local pain with swelling later - Allergic reaction

-

If bee, remove sting by sliding out with fingernail Wipe area clean. Apply ice in both cases. Seek urgent medical attention, especially if sting is around face or neck.

Throughout Queensland

Branched ‘spines’ or hairs on body

Skin lesions, local pain, skin irritation

Remove spines by applying adhesive tape and pull off. Itching may be relieved by prop rietary products like Stingose, Stop Itch, calamine lotion or hand creams.

Throughout Queensland

Wash area. Itching may be relieved by proprietary products like Stingose, Stop Itch, calamine lotion or hand creams.

Coastal Queensland

Cup moth larval/processionary caterpillars

-

-

Whiplash rove beetle (Finch Hatton bug)

Secretion emitted when insect is crushed on the skin

Symptoms may not appear for at least 12 hours  red rash which blisters after 48 hours.

-

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A SPECTS OF S CIENCE MANAGEMENT Organism Assassin Bug

Venom apparatus

Symptoms

First aid Wash area Itching may be relieved by proprietary products like Stingose, Stop Itch calamine lotion or hand creams.

Distribution

Saliva injected by piercing rostrum under head

Sharp pain and local irritation

-

Throughout Queensland

Toads

Venom gland on each shoulder secretes a white fluid. Other venom glands distributed over back.

Contact with eyes, mouth, nostrils causes severe pain and irritation.

Wash fluid from body−if in eyes, irrigate with water for 20 minutes. If ingested, induce vomiting and seek medical aid. Wash hands thoroughly after handling.

Throughout coastal Queensland and Gulf country

Frogs

Toxic chemical elaborated from skin of most

As for toads (very few cases reported)

As for toads

Throughout Queensland

Venom glands associated with spine on base of tail

Severe local pain and swelling

-

Tidal areas of streams and rivers of Queensland beaches and Great Barrier Reef

Amphibians

Fish Stingrays

Stonefish

LETHAL 13 dorsal spines, each with a pair of venom glands. Has the potential to inflict a fatal injury.

-

Immediate unbearable pain Swelling Bluish discolouration of skin Paralysis spreads No recorded death to date

Remove patient from water. Reassure. Immobilise the affected limb. Place the hand or foot in hot (but not boiling ) water. Transfer to hospital.

As for stingrays. Seek immediate medical aid as antivenom is available.

Coastal Queensland, particularly in tropics

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A SPECTS OF S CIENCE MANAGEMENT Organism

Venom apparatus

Symptoms

Bullrout

Venomous dorsal spines

-

Severe pain and/or swelling

Catfish

Venom glands associated with dorsal and pectoral spines

Severe pain and/or swelling

First aid

Distribution

As for stingrays

Coastal streams and rivers of Queensland

As for stingrays

Streams and rivers of Queensland. Some species along coastal and offshore islands. Numerous fish have venom glands always associated with spines.

Ciguatera

Type of fish-flesh poisoning caused by ingestion of contaminated individuals of many varieties of fish commonly associated with coral reefs, e.g. Spanish Mackerel

Numbness and tingling of extremities and lips. Reversal of temperature sensation. Joint and muscle pain. Weakness and headaches. Itchiness, More acute cases: stomach pains, vomiting and diarrhoea.

Seek medical attention immediately.

Possible in all tropical and subtropical sea fish

LETHAL Venom glands associated with chitinous jaws in mouth located between base of tentacles

Often no pain at site of bite, numbness of face/neck, difficulty in breathing, respiratory failure may result in death.

-

Intertidal, subtidal zone of subtropical and temperate coast of Queensland, fairly common in Moreton Bay

Mollusca Blue-ringed Octopus

-

Cone shells

LETHAL Venom-filled dart delivered from a proboscis which extends out suddenly

-

Initial sharp sting Numbness around puncture Severe pain and swelling Progressive muscular weakness and paralysis of voluntary muscles Respiratory failure may result in death.

Apply pressure, immobilisation treatment . Monitor A, B , C. Commence resuscitation if indicated. Seek immediate medical aid No specific antivenom is available.

As for Blue-ringed Octopus.

Common on coral reefs of tropical and subtropical Queensland, but may be found on coastline.

Coelenterates

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A SPECTS OF S CIENCE MANAGEMENT Organism Box jellyfish (Chironex spp.)

Venom apparatus Stinging cells on tentacles

Symptoms -

Terrible pain Massive and linear weals Severe stings cause impaired breathing Death in few minutes

First aid -

IRUKANDJI SYNDROME Small jellyfish Carukui Barnesi.

Stinging cells on tentacles

-

-

Remove patient from water. Avoid adherent tentacles. Douse liberally with quantities of vinegar. Apply pressure immobilisation treatment. Saturate bandage with more vinegar. Monitor A, B, C. Seek medical aid urgently.

Distribution Coastal inshore Queensland−Gladstone north. They are seasonal, being most prevalent from spring to autumn. The most dangerous climatic conditions of the tropics are hot, still days, especially after light northerly winds.

Initial faint sting may not be seen or recognised. Severe muscular cramping pains may start in lower back, limbs, or abdomen after an initial delay of between 10 and 40 minutes. Headaches May cause hypertension, excessively high blood pressure

Remove patient from water. Rest and reassure. Monitor A, B, C. Douse area with vinegar. Apply vinegar-soaked compression bandage. Seek immediate medical aid.

Similar to box jellyfish

Severe pain, burning and itching Linear weals May produce breathing difficulty, nausea, vomiting, drowsiness in children.

-

Apply ice.

-

Contact a doctor if sting is extensive or the patient severely distressed.

Throughout coastal waters of Queensland

Echinoderm Bluebottle Portuguese man of war Fire jelly Moreton Bay stinger Blubber Hair jelly/snottie

Stinging cells, mostly on tentacles

Stinging hydroids

Stinging cells

-

Immediate burning pain continues for some time. Multiple weals develop soon after. Itchiness and redness develop minutes later. No danger to life.

As for bluebottle

Coastal waters of Queensland. Commonly attached to rocks and wharf piles

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A SPECTS OF S CIENCE MANAGEMENT Organism

Venom apparatus

Symptoms

First aid

Distribution

Coral cuts and abrasions

Occur when unintentional contact is made with hard coral.

Initial cut appears insignificant. Danger of untreated cuts becoming infected is severe.

Thoroughly clean the wound as soon as possible remove all infected material.

Coral stings and anemones

Stinging cells

Wealing. Non-specific itchy red rash. Tends to worsen with time. Children may become more severely distressed. Occasionally swelling and migratory pains up limb.

As for bluebottle

Coral reefs. Anemones occur intertidal and subtidal everywhere in Queensland.

Crown-of-thorns starfish

Upper body covered with spines up to 6cm in length. Venom-producing cells are within the epidermal layer covering the spines.

Extreme pain, redness, swelling, numbness and paralysis. (Localised allergic reactions or protracted vomiting in some susceptible individuals.)

Bath in warm to hot water (not boiling) to inactivate the venom and help disperse venom thus reducing its concentration. Seek medical attention. Because the spines are fragile, an X-ray should be taken to make sure that no fragments remain.

Coastal waters of Queensland, especially coral reefs.

Sea urchins Needle-spined sea urchin

Venom in long, hollow, brittle spines

Discoloured wound with violet-coloured fluid. Pain and redness.

-

Coastal waters of Queensland

Flower sea urchin (Toxopneustes pileolus)

LETHAL Venom in the grasping organs ‘pedicellariae’

Intense radiating pain. Fainting and numbness. Generalised paralysis. Loss of voice. Respiratory failure may lead to death.

Seek immediate medical aid.

Coastal waters of Queensland

Mild to severe skin irritation or rash, itchy, made worse by wetting, rubbing and scratching

Apply cooling lotions  calamine, vinegar, or alcohol. Do not rub eyes or face.

Coastal waters of Queensland. Commonly attached to rocks and wharf piles.

Bathe in hot water (not boiling). Give relief from both spine and pedicellariae venom.

Poriferan Sponges

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6.4

SUMMARY OF TREATMENTS FOR SOME ANIMALS

6.4.1

BITES AND STINGS

Snake bite General principles Do not use an arterial tourniquet when treating snake bite. Close observation of the patient is necessary and if breathing or circulation fail, resuscitation must be commenced. Specific first aid treatment Immediately apply a firm pressure bandage over the bite site and wrap it around and beyond the site to the tips of the fingers or toes, then back along the limb to include the joint above. The bandage should be as tight as one applied to a sprained ankle. Keep the limb as still as possible. Do not elevate it. After applying the pressure bandage, immobilise the limb by binding a splint to it (e.g. a piece of timber, a spade handle, any rigid object). If the bite is on the hand or forearm, put the splinted forearm in a sling. It is safe to leave pressure bandages in place until anti-venom is available. Leave splint and bandage on until medical aid is reached. Do not wash venom off the skin as this will assist in later identification. Basis of treatment for snake bite Firm bandaging beyond and above the bite will limit the spread of venom. It has been demonstrated that this spread is further reduced by keeping the patient’s limb still. Inactivation of some components of the venom continues at the site of the bite for several hours. This is why the compression bandage is kept on.

6.4.2

OTHER ENVENOMATION

General principles 1. Do not use arterial tourniquets. 2. Observe the patient closely, and if breathing or circulation fails, commence resuscitation. Treatments Funnel-web spider Treat as for snake bite. Anti-venom vaccine is available. Red-back spider Apply ice and water mixture, but be careful to avoid skin damage from direct application of ice to unprotected skin. Seek medical advice as pain may be severe. Anti-venom vaccine is available is necessary. Blue-ringed octopus Treat as for snake bite. Respiratory arrest occurs very promptly. Commence expired air resuscitation immediately and continue during transport. Seek medical care. Artificial respiration may be necessary in hospital for many hours.

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Bee stings Scrape the sting off with the fingernail or knife blade. An ice and water mixture will relieve the pain. Allergic patients If the patient is known to be allergic, or if there is excessive swelling of the eyelids and around the face and difficulty in breathing, remove the sting as above. Treat as for snake bite when bee stings are on the limbs, and seek medical care. Box jellyfish Flood the adherent tentacles with household vinegar. Apply ice packs to relieve the pain. If the sting is massive or if the patient collapses, apply a pressure bandage, as for snake bite. Watch the patient closely. If breathing stops, commence expired air resuscitation immediately. Seek medical attention urgently. Other jellyfish stings Flush off the tentacles with water. Do not rub or use vinegar. Apply ice packs to relieve the pain. Ticks These are found mainly in scrub country along the coast and are difficult to detect on the body unless engorged with blood. The head is always buried in the skin with only the body visible, and if not removed, the result can be serious. Therefore, when working in tick country or after picnics in tick country, check the body frequently for ticks. Check the dog too. Symptoms The venom may cause paralysis, especially in small children. The paralysis affects, in order: • the lower limbs, • the upper limbs, • the muscles of breathing, and • the facial muscles The bite causes itching, sometimes followed by a feeling of weakness and nausea. Signs The unengorged tick is bluish-black or reddish-brown in colour, oval and flat. Engorged, the tick is globular and up to 5mm in diameter. It tends to find its way into body crevices. Treatment for ticks Tweezers pressed into the skin around the head of the tick should expel it. The tick should not be grasped with the tweezers and pulled out, as this may cause the release of more toxin. If the head does not come out readily, seek medical aid for removal and, if required, an injection of specific tick antivenom vaccine.

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6.5

Hazardous plants Plants with spines and/or stinging hairs Plant

Hazard

Devil’s apple (Solanum capsicoides)

Spines and sharp hairs contain the alkaloid solanine.

Prickly pear (Opuntia spp.)

Sharp long spines and small white hair-like barbed bristles. Stingose may help.

Stinging nettles (Urtica spp.)

Fine transparent stinging hairs on leaves and stems

Stinging Trees (Dendrocnide spp.)

Occur at or near the edge of rainforests. Large rigid hollow stinging hairs on leaves and stems  even dry, dead leaves can sting. Effects persist for weeks, even months.

Stinging vine (Tragi-novae hallandiae)

Stinging hairs on leaves

Plants with corrosive sap Plant

Hazard

Naked lady (Euphorbia tirucalli)

Milky white sap causes severe blistering of skin and can cause temporary blindness if it contacts the eyes.

Poinsettia (Euphorbia pulcherrima)

Sap may be corrosive to sensitive skin. Eye contact requires medical attention.

Spurges (Euphorbia spp.)

Sap corrosive. Eye contact requires medical attention.

Milky mangrove Blind-your-eye (Excoecaria agallocha)

Corrosive sap. Eye contact requires medical attention.

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Plant Headache vine (Clematis glycinoides ) (Clematise icrophylla)

Hazard Juice of crushed leaves can blister the skin.

Plants which are poisonous if eaten (plant material, fruit, flowers, seeds must be ingested to be harmful) Plant

Hazard

Oleander (Nerium oleander )

All parts of the plant are poisonous, a single leaf is considered potentially lethal.

Yellow oleander (Thevetia peruviana)

Probably our most poisonous plant and has been responsible for deaths of several children. All parts are poisonous.

Allamanda (Nerilifolia)

Fruits and sap are poisonous.

Dumbcane (Dieffenbachia spp.)

Plant tissue contains needle crystals of calcium oxalate, a skin and eye irritant.

Flamingo flower (Anthurium spp.)

As per dumbcane

Elephant ear (Xanthosoma violaceum)

As per dumbcane

Philodendron (Philodendron spp.)

As per dumbcane

Castor oil plant (Ricinus communis)

Seeds contain ricin which is extremely poisonous. Two to eight seeds are lethal.

Black bean or Moreton Bay chestnut (Castanospermum australe)

Seeds are poisonous, causing vomiting, severe diarrhoea which may lead to dehydration.

Stinking passion flower, corky passion vine, white passion vine (Passiflora spp.)

Green parts can yield hydrocyanic acid (HCN).

119

A SPECTS OF S CIENCE MANAGEMENT Crab's eye, gidgee-gidgee, precatory bean, rosary pea, jequirity bean (Abrus precatorius)

Damaged seeds highly poisonous if ingested-can cause vomiting, diarrhoea, trembling and cold sweat, weakness and collapse.

Plant

Hazard

Cunjevoi (Alocasia macrorrhizos)

Sap corrosive and causes severe stinging. Handling plant produces stinging. Bathe and wash off with water. Eye contact may require medical attention.

Lantana spp.

Fruits and leaves contain toxins; fatal poisoning of children has occurred after eating the fruit.

Arum lily (Zantedeschia aethiopica)

All parts poisonous

Pineapple Zamia (Macrozamia miquellii)

Seeds are highly toxic.

Green cestrum (Cestrum parqui)

All parts poisonous, but fruits most toxic

Blackberry nightshades (Solanum nigrum)

Green fruit is poisonous.

Angel's trumpet (Datura candida)

All parts are poisonous.

Wintersweet (Acokanthera oblongifolia)

Bark, leaves and fruit are recorded as poisonous, causing severe gastro-intestinal irritation and affecting the heart.

Syngonium (Syngonium podophyllum)

Flowers if eaten have caused death.

Finger cherry (Rhodomyrtus macrocarp)

Fleshy red fruits have been known to cause blindness.

White cedar (Melia azedarach var. Australasica)

Seeds may cause nausea, vomiting, diarrhoea, severe thirst, cold sweat, sleeplessness, convulsions, possibly death. Leaves and bark may also be poisonous.

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6.6 Summary of treatments for some plants Hazards

Method

Symptoms

First Aid

Poisoning

Most common:

-

-

Contact Poison Information Centre Induce vomiting with syrup of ipecac, only if the patient is having difficulty breathing or is losing consciousness.

-

Vomiting Diarrhoea Hallucinations Pain or swelling of the mouth, tongue or throat Difficulty in breathing Unusual behaviour

-

Itching Reddening of skin Skin lesions Localised pain Blistering Very severe pain if splashed in eyes

-

Irrigate eyes well with water 15−30 minutes. Apply methylated spirits to remove milky sap from skin. Urgent medical attention may be required. Adhesive tape may help remove some stinging hairs.

a) b) c)

ingestion of oleander berries ingestion of mushrooms ingestion of plant products (experimenting with plants as mood-altering drugs)

Some school-age children have been poisoned by experimenting with angel's trumpet (Datura), and with white cedar berries or extracts brewed from similar trees. As a general rule, no plants or plant parts should be eaten. Skin and eye irritation

-

Plant and fluids e.g. sap milky or resinous sap is not water soluble. Spines and hair-like bristles, stinging hairs.

-

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6.7

BLOOD, BLOOD PRODUCTS, BODY FLUIDS

All such materials should be regarded as infected with HIV and/or other blood-borne pathogens, and teachers of science must adhere rigorously to the following protective measures to minimise exposure to these agents. (Refer to Australian National Council on AIDS Bulletin No. 3, ‘Laboratory Safety Guidelines’.)

6.7.1 (a)

(b) (c)

(d)

6.7.2 (a) (b) (c) (d) (e)

6.7.3 (a) (b) (c) (d) (e)

PERSONAL PROTECTION Gloves: All staff and students should wear gloves when contact with blood or body fluids is envisaged. If gloves are punctured, they should be removed, disposed of and the hands washed. Gloves should be removed before handling the telephone, performing office work or on leaving the laboratory. Facial protection: Staff and students should wear safety glasses or face shield when there is a risk of splashing or spraying of blood or body fluids. Laboratory coats and aprons : Plastic aprons should be worn when contact with blood or body fluids is expected. Used aprons must be wiped with a disinfectant solution. If fabric laboratory coats are used and they have been contaminated with blood or body fluids,they must be soaked in a bleach solution before laundering. All equipment must be disinfected after use.

SPILLS Gloves must be worn. Remove the blood or body fluids with absorbent material. Using a detergent solution, clean the spill area thoroughly. Wipe down the spill area with disposable towels soaked in a disinfectant solution containing a minimum of 500mg/L (ppm) of available chlorine. If the spill site is porous then a disinfectant solution containing at least 5000ppm of available chlorine should be used. Dispose of contaminated waste material.

WASTE DISPOSAL Sterilise by autoclaving or heating in a pressure cooker for 15 minutes and dispose of as general waste. Blood and body fluids should be disinfected and washed to waste with excess water, taking care to avoid splashing. Any cleaning materials utilised such as gloves, cloth, chux, should be placed into a plasticlined tidy bin specific for blood, blood products and body fluids. Regular waste should be placed into a plastic garbage bag that is tied off before disposal in the general waste. Direct handling of contaminated waste (e.g. bandages, bloodstained items) should be eliminated. All first aid waste should be considered as a potential source of infection. Waste should be secured in a plastic bag that is clearly identified as BIOHAZARD prior to disposal in the general waste. Appropriate personal protective equipment should be provided, used and maintained.

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6.8

LIVE ANIMALS

6.8.1

RISKS

(a) (b)

(c)

(d)

(e)

The risk level involved in the handling of live animals may vary according to the nature of the activity and the age and experience of the client group. Teachers should refer to Section 6.3 Hazardous animals, to ensure that the ris ks likely to emerge from handling live animals have been taken into account and that the necessary procedures for countering such risks are taken. Hazards that may be encountered in this activity include: (i) animals (most animals can inflict bites and should be handled with great care); (ii) parasites (animals carry parasites which could have adverse effects on humans); (iii) dissection material (all material used for dissection should be treated as though it were contaminated); (iv) equipment (all equipment should be sterile, particularly dissecting instruments); (v) vermin and insects, which are a health hazard to both humans and the animals being kept, are attracted to animal food; and (vi) mouldy and decaying animal food and animal wastes, which may be a health hazard due to the presence of bacteria and other micro-organisms. Hazards that may be encountered in activities involving the handling of living marine organisms include: (i) envenomation (poisoning); and (ii) bites, stings, spines (wounds). Teachers are reminded to refer to the hazards section in paragraphs 2.7 to 2.23 in HS-10: Workplace Health and Safety Guidelines  Curriculum in the Department of Education Manual, HS-10/9: Handling Living Marine Organisms and HS-10/48: Handling Live Animals  Science.

The keeping of live animals for experimental purposes is controlled by the Australian Code of Practice for the Care of Animals for Scientific Purposes produced by the National Health and Medical Research Council, CSIRO and Australian Agricultural Council. The code covers all live, non-human vertebrates. Invertebrates are not currently the subject of relevant legislation. If live animals are to be kept, the following questions must be addressed: (a) (b) (c) (d) (e) (f)

Is it essential for live animals to be kept? Have alternatives to animal experiments been investigated? Has the number of animals been kept to a minimum? Will the animals be housed under appropriate conditions? Who will take responsibility for feeding and caring for animals during holiday periods? Have procedures been established for the safe handling of animals? Animals do carry diseases and therefore procedures must be designed to minimise the risk to staff and students of being bitten or scratched.

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6.8.2 (a)

(b)

6.9

COLLECTION OF LIVE ANIMALS All native fauna should be treated as protected under the Fauna Conservation Act and therefore not collected. For further information contact: The Department of Environment National Parks and Wildlife Service PO Box 155 Brisbane Albert Street Q 4002 Telephone: (07) 3227 7806 Cane toads and rabbits are classified as feral and are not covered by the Fauna Conservation Act. For further information contact: Rural Lands Protection Board Telephone: (07) 3224 7455

DISSECTIONS

Prior legislation concerning the use of animals in schools has been amended so that a scientific experiment must be conducted in accordance with the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes. A scientific experiment is defined in the Animals Protection Act Amendment Act 1991 as ‘any experiment, procedure, test or study that is conducted on an animal in the course of which an animal is subjected to surgical, medical, psychological, biological, chemical or physical treatment; or abnormal conditions of heat, cold, light, dark, confinement, noise, isolation or overcrowding to which an animal of that species or kind is not accustomed; or abnormal dietary conditions; or electric shock or radiation treatment; or any material or substance is extracted or derived from the body of the animal; and that is for the purpose of acquiring, developing or demonstrating knowledge or techniques in any field of science, but does not include [normal veterinary and husbandry procedures]’. The purpose of the code is to: • • • • •

emphasise the responsibilities of both investigators and institutions using animals; ensure that the welfare of animals is always considered an essential factor; ensure that animal use is valid; minimise the number of animals used in projects and limit or avoid pain or distress; and promote the development and use of techniques which replace animal experiments.

Some of the general principles specified in the code are: (a)

(b)

(c)

Experiments on animals may be performed only when they are essential to obtain and establish significant information relevant to the understanding of humans or animals, to the maintenance and improvement of human or animal health and welfare, to the improvement of animal management or production, or to the achievement of educational objectives. People who use animals for scientific purposes have an obligation to treat the animals with respect and to consider their welfare as an essential factor when planning and conducting experiments. Techniques which replace or complement animal experiments must be used wherever possible. Experiments must be scientifically valid, and must use no more than the minimum number of animals needed. Experiments must use the best available scientific techniques and must be carried out only by persons competent in the procedures they perform. Experiments on animals must not be repeated unnecessarily or conducted simply as a motivational tool in the teaching of science.

The code specifies that institutions using animals for scientific purposes must establish animal experimentation ethics committees (AEECs) to ensure that all animal use conforms with the standards 123

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of the code. Since animal pain and distress cannot be evaluated easily, investigators must assume that animals experience pain in a manner similar to human beings. Decisions regarding an animal’s welfare must be based on this assumption unless there is evidence to the contrary.

6.9.1

THE CARE AND USE OF ANIMALS IN SCHOOLS

Policy and Guidelines (Vertebrates Only)

Developed by the Animal Experimentation Ethics Committee

On behalf of: Education Queensland, the Queensland Catholic Education Commission, the Association of Independent Schools of Queensland

POLICY Policy Statement Schools have a major responsibility to promote and model best practice in the care, use and welfare of animals. Schools must comply with the Animals Protection (Use of Animals for Scientific Experiments and Teaching) Regulations 1991 through the centrally established Animal Experimentation Ethics Committee (AEEC). These guidelines apply only to vertebrates. This will involve the school maintaining a register for activities involving vertebrate animals listed in the Schedule of Approved Activities or seeking approval from the AEEC for those activities not listed. Accountabilities The AEEC will monitor and authorise the care and welfare of animals in schools by all teachers in accordance with the policy outlined here. The ultimate aim is to reduce the number of animal used for experimental purposes and to promote greater use of alternatives in teaching. Where animals are used in schools for activities as outlined in the Schedule of Approved Activities, no specific written application or approval is required. However, a register of all activities in volving animals, including the numbers of each species, and the names of teachers involved must be compiled (see Appendix 1). This register is to be kept at the school and must be made available on request to the AEEC.

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Teachers wishing to undertake activities other than those listed in the Schedule of Approved Activities, that is, non-scheduled activities, must seek specific approval from the AEEC using the application form in Appendix 2. Schools must keep a copy of the approval on file, and the activity must not proceed until the approval has been received from the AEEC. Schools must comply with the policy and guidelines outlined here to satisfy legislative requirements. Principals are requested to bring this policy to the attention of all staff members. Policy source This policy has been developed using the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes, which is based upon the Animals Protection (Use of Animals for Scientific Experiments and Teaching) Regulations 1991. Contact Applications for approval for non-scheduled activities must be submitted to: The Executive Officer The Animal Experimentation and Ethics Committee Teaching and Learning Branch Education Queensland PO Box 33 Brisbane Albert Street Q 4002

Related materials Several curriculum modules in the Department of Education Manual also relate to the care, use and welfare of animals: Handling Live Animals Handling Living Marine Organisms Biological Activities Safe Work Practices Conducting Science Experiment Activities Aspects of Science Management: A Reference Manual for Schools and these guidelines.

HS-10/12, HS-10/48 HS-10/9 HS-10/49 HS-10/54

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Guidelines The Care and Use of Animals in Teaching These guidelines outline the special ethical considerations and issues of responsibility when animals are used to demonstrate knowledge or techniques in any learning area. They do not replace the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes, which is incorporated in Queensland legislation, but are designed to emphasise the principles most relevant to the use of animals in teaching. General principles 1.

Animals may be used in teaching activities only when there is no practicable or suitable nonanimal alternative to achieving the educational goal.

2.

All teaching activities that involve the use of animals must meet the requirements specified in the Schedule of Approved Activities. If the activities are planned, schools must apply to the AEEC for approval. In granting approval the AEEC must be satisfied that the activity is justified on the basis of educational value, there is no suitable alternative and the impact and the numbers of animals involved are kept to a minimum.

3.

Where valid alternatives exist, the AEEC may ask applicants to justify why they have chosen to use live animals instead of an alternative.

4.

The school should offer students the opportunity to use alternatives not involving animals when these alternatives are available and compatible with educational objectives.

5.

All students should be given the opportunity to discuss the ethical, social and scientific issues that are involved in people’s use of animals for scientific purposes.

Responsibilities when Working with Animals When animals are to be used to achieve educational objectives, the teacher nominated by the principal is responsible for the care and use of the animals from acquisition to appropriate disposal. The teacher should: •

ensure that all care and use of animals are in accord with the provisions of the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes;

•

have relevant training and demonstrated experience in caring for and using animals;

•

incorporate methods that may replace, reduce or refine the use of animals where such methods are available and compatible with educational objectives;

•

obtain AEEC approval before any activity not listed on the Schedule of Approved Activities is undertaken and ensure that the activity is conducted as directed and approved by the AEEC. Animals should not be involved in these activities for any longer than absolutely necessary;

•

ensure that there is close, competent supervision of all students working with animals.

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The responsible teacher should ensure that, when students are directly involved, they are instructed in the appropriate methods of handling and caring for animals. Students should be able to demonstrate their ability to perform necessary tasks with care and competence. Teachers supervising students who are undertaking assignments and projects involving animals should ensure that, prior to using animals, students receive appropriate instruction. This should include the ethical and legal responsibilities involved in the use of animals for scientific purposes as well as appropriate methods for animal care and use. The person supervising such students is responsible for the welfare of the animals. Teachers are also responsible for ensuring that animals are disposed of in an appropriate and responsible manner when they are no longer required.

Animals in schools Since school premises are unoccupied for part of each day, on weekends and holiday periods, procedures must be in place to ensure the maintenance of satisfactory levels of animal welfare during these times. Arrangements for regular and ongoing monitoring of animal health and wellbeing should be made. Security is a major issue, and housing and holding facilities should be secure against human and animal interference. The principal is responsible for making sure that a person is available to respond to any emergency that may arise. The principal of the school is ultimately responsible for ensuring that the following activities are not undertaken : 1.

surgical procedures without anaesthesia other than in the conduct of normal animal husbandry operations;

2.

deliberate exposure of animals to infectious organisms;

3.

nutritional deficiency experiments and trials that cause distress;

4.

administration of toxins, poisons, ionising radiation (Class 2, 4 or 4) or other bio -hazardous materials;

5.

stimuli that cause distress.

When the purpose of a curriculum activity is student interaction with animals, the observation of animals by students in purpose-built facilities, in animals’ natural environments or under field conditions is preferable to introducing animals temporarily into the school. Students should not be allowed to take acquired animals home unless the school is satisfied that the animals will be cared for adequately and responsibly. Up-to-date and complete records must be available for inspection at all times. The records must include : •

a register of all activities involving animals including the numbers of each species used and the names of teachers involved. Schools may be required to submit a summary of these data. This register is intended to be an annual summary of all the activities undertaken using animals.

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Teachers may choose to keep data as annotations within work programs and update the register at the end of each semester. Individual activities need be listed only once. •

copies of all approvals to conduct activities not covered by the Schedule of Approved Activities.

A sample page for a register is provided in Appendix 1.

Acquisition All animals used in schools must be obtained legally. Teachers are reminded that many free-living animals are protected by law and permits are required to catch or keep such animals.

Disposal Several options are available for the disposal of animals when no longer needed: •

Return to source: Animals obtained from farms, hatcheries, homes etc. may be returned to their place of origin, providing prior arrangements have been made and there is no risk of the introduction of infectious disease.

•

Release to the wild: Animals obtained from nature should be returned only on the advice of appropriate officers from the National Parks and Wildlife Service. Non-native animals, domestic and cage -reared vertebrates of any kind must not be released into the wild.

•

Release of animals to students: Students should not be permitted to take animals home unless the school is satisfied that the animals will be cared for adequately and responsibly. This also applies to the temporary release of animals to students to care for on weekends and during holiday periods.

•

Euthanasia: If euthanasia is necessary, an accepted humane method must be used by a person competent in the chosen method. Animals used for dissection or carcass appraisal should be killed using an accepted humane method. If the meat is intended for human consumption, the animal must be slaughtered in a licensed premise.

•

Sale: Live farm animals may be sold through usual channels to appropriate purchasers.

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Appropriate species Remember that at times even certain approved activities could cause unnecessary suffering to some species because of their unique requirements. As a rule, schools should use species that are: • • •

hardy, able to thrive in captivity and from a habitat that can be readily duplicated; fairly simple to care for and do not present insurmountable problems for weekend and vacation care; tolerant to being handled and have easy-to-meet food requirements.

Educational Objectives All activities involving animals must have a valid educational objective. Teaching programs should clearly state objectives that explain why the use of animals is required. The following are examples of appropriate objectives that build on the partnership between humans and animals in learning situations where neither group suffer and both gain from the experience. There may also be other more detailed objectives set by the teacher that are specific to the lesson at hand. These specific objectives may also be useful in considering whether alternatives to the use of animals are possible: • To develop in students a sensitivity to, and awareness of the needs of, animals through positive experiences gained in circumstances where high-quality animal care is always provided. • To teach respect for all life through the use of humane methods of scientific inquiry into the natural characteristics of animals. • To use the students’ natural affinity for, and curiosity about, animals to build sound powers of observation and understandings of the roles of animals in the environment. • To teach students moral and ethical responsibilities towards animals. • To develop in students the knowledge and skills necessary to care for animals.

Using these Guidelines These guidelines have been developed to help schools to comply with legislative requirements with a minimum of administration and paperwork. The Schedule of Approved Activities and these guidelines specify how activities involving animals should be managed so that the welfare of the animals is protected at all times. Where they exist, the relevant Codes of Conduct should be consulted for industry standards and any conditions pertaining to particular activities. Some activities require special precautions to ensure that unintended side -effects or consequences do not occur. Additional information about some of these activities has been provided in the section on Activities and Terms, page 133.

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Schedule of Approved Activities: Categories The following list of activities describes the levels of experience or expertise required before teachers can undertake a particular activity. In compiling this schedule the Animal Experimentation Ethics Committee has attempted to categorise the possible uses of animals that are most likely to be requested by teachers. It describes which uses can be undertaken routinely and which are expressly forbidden under the legislation.

The utmost care should be exercised by teachers and students when any of these activities are undertaken to ensure the humane treatment of the animal. Each participant should be aware of the educational objectives that have warranted the use of this animal.

Teachers using Category 1, 2 or 3 activities, must keep a school register of all activities involving animals including the number of each species and the names of the teachers. Any activities not specifically listed are ‘non-scheduled’, and application for approval using the application form (Appendix 2) must be made to the AEEC. The activities are divided into three categories:

Categories

Specifications

1

• The activity may be undertaken without application for approval to the AEEC. • The activity must be recorded in the school’s register using a pro forma such as in Appendix 1. • The activity must have a valid educational objective and comply with the guidelines outlined here.

2

• The activity may be undertaken without application for approval to the AEEC. • The activity must be recorded in the school’s register using a pro forma such as in Appendix 1. • The activity may be undertaken only by students with the relevant backgrounds and maturity who are engaged in a recognised component of a science or agriculture work program. • The leader must have expertise or previous experience with the activity.

3

• The activity may be undertaken without application for approval to the AEEC. • The activity must be recorded in the school’s register using a pro forma such as the one in Appendix 1. • The activity should only be a demonstration by the leader to students or performed by students as part of skill acquisition within a recognised vocational education or agricultural course. • The leader must have expertise or previous experience with the activity.

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Schedule of Approved Activities Activity

Category

1. 2. 3.

1 2

4.

5.

6.

7.

8.

9.

Observation of normal behaviour of animals Capture, restraint and handling of non-free living animals Measurement or observation of: (a) body weight (b) growth (c) changed body proportions (d) pulse or blood flow (e) respiration (f) temperature (g) age by dentition Measurement or observation of mild dietary effects * : (a) high/low protein (b) high/low energy (c) high/low fat (d) palatability * See page 129k, no.4. Behavioural activities * : (a) imprinting in chickens or ducklings (b) mazes with rats or mice (c) taming/gentling sheep, goats or cattle (d) training for performance or showing (e) breaking in cattle or horses * See page 129k, no.5. Collection of materials from animals: (a) ruminal fluid (b) faeces (c) blood (d) wool (e) milk (f) poultry embryos from fertile eggs (0–14 days) (g) saliva (h) urine Assisting the teacher in the management of sick, diseased or injured animals Zoonosis must be avoided, and care taken to prevent distress. Examples: mastitis in sheep and cattle, assistance with difficult births Dissection (a) bull’s eye (b) sheep pluck (c) sheep heart, kidney (d) chicken (wing or leg) (e) fish (f) mouse, rat (g) toad (h) hen Standard husbandry activities for livestock and other animals: (a) General management – tail docking of lambs and piglets

2 2 2 2 2 2 2 2 2 2 2

2 2 2 2 3

3 2 3 2 2 2 2 2 3

1 1 1 1 1 2 2 2

3 131

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(b)

(c)

(d)

– hoof trimming, horseshoeing _ nail clipping – tooth trimming/removal in piglets – mulesing in young sheep (refer to industry guidelines) – coat care and clipping – shearing of sheep and goats – crutching – beak trimming – debeaking (in intensive poultry systems) – trimming spurs on roosters – clipping flight feathers – mechanical dehorning – chemical dehorning – horn tipping – application of nose ring – HGP implants – use of electric prodder – bath/shampoo dogs – transporting, carrying and lifting animals Identification – tattoo application of livestock – ear marking of livestock – ear tagging of livestock – freeze branding of cattle and horses – fire branding – microchip tagging – tail tagging Reproduction and breeding – castration of immature stock (refer to industry guidelines) elastrator ring knife burdizzo – semen collection – artificial insemination (including injection of prostaglandins) – pregnancy diagnosis (refer to industry guidelines) – embryo transfer Health – vaccination of livestock – administration of oral medications (tablet, capsule, liquids) – injection of drenches or other appropriate non-restricted substances into livestock – external parasite control and treatment – use of stomach tube (calves only) – administer eye-drops, eardrops, creams and ointments – apply dressings and bandages to limbs, e.g. cats and dogs

3 2 3 3 2 2 2 2 3 3 2 3 3 3 3 3 3 2 2 2 2 2 2 3 3 1 3

3 3 3 3 2 2 3 2 3 2 2

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Activities and Terms 1. Observation Observation implies that the student is to observe the normal behaviour of an animal under circumstances that are not stressful for the animal. This is particularly important when breeding is part of the observation. Consideration must be given to the suitability of the animals to be used in breeding and the proper care of offspring. 2. Capture, restraint and handling These skills should be taught as part of the routine management practices required to maintain the animal’s health and wellbeing and where the animal benefits from such skills being acquired by students. 3. Measurement The measuring of body dimensions/functions in an animal can usually be done with a minimum of interference and should not cause any pain or distinct discomfort to the animal. 4. Dietary effects No animal should suffer any form of nutritional deprivation. It is no longer acceptable for a teacher to justify the use of a live animal in an experiment that would deprive the animal of its normal requirements of food or water. However, a teacher may wish to demonstrate the variation in growth brought on by normal versus enhanced protein, energy or fat where such mild dietary modification is offered to the animal and causes no discomfort. The effects of nutritional deprivation are well documented in available literature, and many study aids are also available. 5. Behavioural activities The alteration of an animal’s natural behaviour to conform to a desired pattern or the demonstration of a natural behaviour in an abnormal context should not disadvantage the animal. It also needs careful justification of the educational benefits, and this needs to be thoroughly explained to students. 6. Collection of materials from the animal The collection of material directly from an animal should not cause the animal distress and should only be done if strong justification can be made. The clipping of hair or wool does not normally interfere with the animal’s wellbeing, but plucking of either may. Faeces can be collected from the area in which the animal is kept, as can other material for study. Such collection of material should not interfere with the animal since it can be part of the normal maintenance of the animal’s accommodation. Where the taking of materials from an animal necessitates bodily invasion (such as blood and ruminal fluid), extreme care must be taken to ensure that: • educational objectives justify the activity; • the operator is well qualified to perform the activity using the correct sterile equipment; • the activity is performed so that it causes minimal stress. The frequency and volume of fluids collected (such as blood) must be carefully considered in the context of an animal’s age, health and current status.

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7. Assisting the teacher’s management of sick, diseased or injured animals A teacher’s management of unwell animals can have a profound influence on a student’s attitudes towards animals. While it is important to recognise that the primary focus of the care of sick, injured or diseased animals is the animal’s welfare, the thoughtful treatment of the animal also presents an excellent educational opportunity. The experience can build students’ knowledge, skill and empathy for the animals in their charge. Students should learn to recognise the signs of an unwell animal, to seek expert advice on treatment and to follow a course of action centred on the best interest of the particular animal. 8. Standard husbandry activities Only activities that can be justified as generally acceptable and routine for a particular species and done or closely supervised by a competent operator should be performed in schools. All teachers involved in these activities are responsible for keeping up to date on the most humane and effective methods of performing these activities. They should ensure that recommended facilities and equipment are available and used at all times.

Summary of Procedures Please note the following procedures only apply to schools where vertebrates are kept or used.

1.

Read these guidelines thoroughly.

2.

Establish the curriculum justification for the activity (objectives, direct relationship to syllabus or work program).

3.

Decide whether the proposed activity is Scheduled or Non-scheduled. (See Schedule of Approved Activities in these guidelines, pages 131 - 132.)

4.

If the proposed activity is listed in the Schedule of Approved Activities:

5.

If the proposed activity is not listed in the Schedule of Approved Activities:

a. Refer to sample to help you fill in a copy of the School’s Register of Scheduled Activities (Appendix 1) and file a copy.

a. Fill in and send an application form (Appendix 2) to AEEC.

b. Proceed with the activity following the guidelines so that the welfare of the animals is protected at all times.

c. File approval when received and proceed with the activity following the guidelines and any conditions specified by AEEC.

c. Respond promptly to any request for information from AEEC.

b. Await advice.

d. If approval is not given, do not proceed with the activity. e. Respond promptly to any request for information from AEEC.

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Appendix 1 School’s Register of Scheduled Activities

Date

Type of Activity

Category

No. of Animals

Species

Responsible Teacher/s

2.8.96

Nutritional trial

2

5

Chickens

Mrs Jones

Term 2, 1997

Measurement of – body weight – temperature Mulesing of sheep Crutching of sheep Ear marking

2

23

Sheep

Mr Brown

22 April– 10 May

Observation of normal behaviour of animals

1

2

White mouse

Ms Jackson Mr Dalton Mrs Williams

June

Dissection of mouse

2

24

Mice

Mrs Summers Mr Smith

E L P M A S 3 2 2

(To be filed in school records)

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School’s Register of Scheduled Activities Date

Type of Activity

Category

No. of Animals

Species

Responsible Teacher/s

(To be filed in school records) 136

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Appendix 2 Application Form for Non-scheduled Activities Project title ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... .................

Personnel involved and qualifications ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ..................

Description of proposal ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ..............................

Justification (objectives, direct relationship to syllabus/work program, alternatives explored) ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... 137

Aspects of Science Management ....................................................................................................................................................... .................................................................................................................………………………… ………………………………………............................................................................................... ................................................................

138

Aspects of Science Management Procedural details: • Species and number of each ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ........................

Source ....................................................................................................................................................... ....................................................................................................................................................... ............ • Time to be kept ....................................................................................................................................................... ....................................................................................................................................................... ............ • Housing ....................................................................................................................................................... ....................................................................................................................................................... ............ • Disposal ....................................................................................................................................................... ....................................................................................................................................................... ............ • Nutrition/special diet ....................................................................................................................................................... ....................................................................................................................................................... ............ 139

Aspects of Science Management Risk management/health regulation procedures ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ........................

140

Aspects of Science Management Special ethical considerations ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ..............................

Proposed dates ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... ....................................................................................................................................................... .............................. Declaration by teacher/s undertaking proposed non-scheduled activity with animals stating that any required licenses are held and that they are aware of responsibilities set out in the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes and relevant legislation.

Name: ................................................................................................................................... (block let ters)

School: .................................................................................................................................. Signature: ............................................................... Date: ..................................

AEEC reference number: ...................................................................................................... AEEC’s recommendation: .................................................................................................... AEEC chairperson’s signature: ............................................................................................ Date: .....................................

Return to:

The Executive Officer 141

Aspects of Science Management The Animal Experimentation and Ethics Committee Teaching and Learning Branch Education Queensland PO Box 33 Brisbane Albert Street Q 4002

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7.

SCIENCE FACILITIES AND EQUIPMENT

7.1

THE ROLE AND DUTIES OF THE SECONDARY SCHOOL SCIENTIFIC ASSISTANT

The duties to be performed by the scientific assistant in a state secondary school will be determined by the principal/head of department having due regard to the nature of the position and the effective functioning of school activities. The duties of a scientific assistant are directly related to the technical work of the area in the school used for teaching science. The primary role of the position of scientific assistant is to provide support to the head of department and teachers of the school science department, thereby contributing to the effective and efficient management of that particular area of the school. Such support covers a range of activities including assisting teachers in setting up demonstration apparatus, handling and preparing chemicals and biological material and generally assisting with teaching material for science classes. Scientific assistants are specifically engaged for duties within the science department of the school and report in the first instance to the respective head of department but are ultimately responsible to the school principal. Scientific assistants may report directly to the school registrar on some issues. The scientific assistant will not be required to accept responsibility for classroom management or control or to take part in lesson procedures. Science teachers should not access the preparation area or chemical store without consulting the scientific assistant. In carrying out the allotted duties, the scientific assistant will make a large contribution to the effective functioning of the science department and should find many opportunities to interact with both teachers and students. Instructions for the use of science facilities by students should, however, always originate from the teachers of science. For greater efficiency, the scientific assistant and the science head of department/principal could establish checklists of general organisational tasks that the scientific assistant needs to carry out on a daily, monthly and yearly basis. Duties performed by the scientific assistant may include a mix of the following activities: • prepare scientific experiments and demonstration apparatus for teachers of science with due notice (at least 24 hours). Experimental materials may be either centrally located for collection by science teachers or can be distributed to classrooms just prior to the lesson; • prepare, with due notice, samples (by measuring, drying, grinding etc.) for subsequent analyses; • maintain store rooms, preparation rooms and laboratories in a clean, safe and orderly manner in accordance with the Department of Education Manual (DOEM) modules comprising the Workplace, Health and Safety Guidelines; • handle and prepare laboratory equipment and biological materials in a safe manner; • prepare solutions of known concentration from bulk supplies including concentrated acids; • monitor chemicals and associated supplies and prepare requisites; • oversee storage, control and maintenance of laboratory equipment and apparatus, initiating or organising repairs as required; • advise Head of Department of maintenance requirements requiring specialist assistance, e.g. laboratory fume cupboards; • dispose of laboratory wastes in a safe and proper manner; • take simple measurements, e.g. pH, weighing crop yield; • prepare and maintain displays; • assist with preparation and maintenance of simple charts, diagrams and models;

ASPECTS OF SCIENCE M ANAGEMENT

• • • •

collect and/or receive deliveries of stock, unpack and check invoices, store stock appropriately; maintain the chemical stock record; conduct an annual stocktake of materials and equipment within the area for teaching science; monitor safety and first aid requirements within the area for the teaching of science. It is the responsibility of the science teacher to trial experiments prior to the lesson and to employ safe practices, risk assessment and risk management; • care for wall charts, museum cases and noticeboards; • participate in field trips as directed by the head of department/principal; • assist in field trip preparations which may include arranging bookings and appropriate materials. For further information, consult the position description of Scientific Assistant, State High School, from the department.

7.2

GENERAL GUIDELINES FOR THE CARE OF SCIENCE FACILITIES AND EQUIPMENT

All teachers of science and scientific assistants must be fully aware of all aspects of science safety. The Department of Education Workplace Health and Safety Guidelines  Curriculum  Core and Activity Modules contain extensive sections on safety, and the relevant section should be consulted whenever science activities are being planned or carried out. While safety is by no means the sole or even chief responsibility of a scientific assistant, this person is in constant contact with the laboratory and should act as a watchdog, alerting teachers to potential hazards and encouraging safe practices. At the same time, appointment of a scientific assistant in no way absolves teachers from employing safe practices, risk assessment and risk management. In the numerous instances where there is no scientific assistant, the responsibility for safe management of the laboratory rests solely with science teachers. The idea of a planned program or regular timetable of checks has much to commend it, and a year planner should be drawn up showing when certain checks are to occur. For example, stocktake should precede ordering for obvious reasons. If ordering takes place in September, stocktake should be about the beginning of Semester 2. A date for electrical checks should be set in consultation with the local electricians, and the electrical check planned for that date. As well, regular checks of taps, gas outlets, electrical leads, labels on reagent bottles, chemicals, glassware etc. should be scheduled, and a regular time set aside for cleaning-up and putting away. If this is not done, laboratories can become untidy, inefficient and potentially dangerous. Certain types of plants require inspections and maintenance by specialists (often detailed within Australian Standards). These activities should be included within the program of checks. For example, laboratory fume cupboards should be inspected, tested and maintained at periodic intervals varying from 6 to 12 months depending upon individual requirements. Compressed air receivers, compressors and vacuum pumps are examples of other types of plant requiring regular inspection and servicing. Suitable goggles, gloves and coats will provide an extra measure of protection for the scientific assistant or teacher of science. Types of protective clothing for the assistant or teacher include safety glasses or goggles, coats (doc tors’ gowns or dustcoats), gloves (household rubber gloves or PVC) and aprons. Science rooms and storerooms are areas of continual activity by teachers and students, so maintenance activities must be continuous. These activities would relate to the following: (a) attention to working fittings, such as gas taps, sinks, sliding chalkboards, water purifiers, car batteries etc.; (b) the proper placement and replenishment of stores and reagents;

(c) (d)

the proper placement of audiovisual materials, e.g. charts, models, films, chalk etc.; the proper placement and care of records; 144

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(e) (f)

the repair of equipment (within reason) and maintenance of gear, e.g. oiling of moving parts etc.; the organisation and maintenance of labels on gear and storage locations.

Science equipment needs constant supervision to maintain it in working order, e.g. projector lamps should be tested, perished rubber tubes should be discarded etc. Working surfaces should be inspected for spills of corrosive liquids, residual glass fragments etc. Gas supplies should always be turned off at the main after use, and attention should be given to the condition of each benchtop gas tap. Attention should be called to any cases of malicious damage or leaks. Gas burners should also be inspected to determine that: (a) (b) (c)

the air ring is adjustable; the gas hole is clear; the rubber tubing is not split or perished.

Plumbing should be inspected so that attention may be called to water leaks and blocked drains. Equipment should not be left out on work surfaces unless this is specifically required by a teacher. Liquids spilt on walking surfaces should be cleaned away immediately. Irrespective of whether a scientific assistant is employed or not, it is the duty of every teacher of science to play an active and positive role in attending to laboratory management and the science head of department must regard instruction in such matters as part of the obligatory professional development of both ancillary and professional staff. Materials commonly used (e.g. chemicals, glassware, burners etc.) should be readily accessible. For other materials (e.g. telescopes) less accessible spaces can be utilised. Sometimes these materials may be stored in displays. Projectors, tape recorders etc. should be stored away from dust and chemicals. Microscopes should be covered by plastic hoods and stored in dust-free cupboards or on shelves at bench level. A microscope is easily carried by holding the microscope arm. Electric balances and centogram balances should always be covered with a plastic hood to protect them from dust. In order to provide experimental equipment for use, the following information should be attained by either the scientific assistant or the teacher of science: (a) (b) (c) (d)

(e) (f) (g) (h) (i) (j) (k)

detailed account of all equipment required; knowledge of the required placement of this equipment; location and preparation of chemicals, if required; locating and setting out the equipment: apparatus trolleys, trays or suitable boxes may be used to carry equipment; materials should be placed in a location convenient for the particular class for which it is required; the setting-up of apparatus, in the case of demonstrations, so that it is ready to operate; the production of more materials as needed; the recording of breakages and depleted non-durable materials; the removal and cleaning of apparatus, where relevant; the dismantling of equipment, where relevant; the return of each article to its correct storage location; a report of missing articles not reported broken.

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7.2.1

CLEANING

Glassware should be clean and dry before use. Cleaning is best done immediately after use as this prevents the staining of work surfaces and the hardening of materials on the glass. (a) (b)

General cleaning The first step in cleaning is to appropriately discard leftover materials. Cleaning agents (i)

Using detergents

Soak glassware in hot water with detergent. To wash, the simplest method is to use liquid or powder detergent, introduce it directly into the apparatus, moisten with water and brush well with the aid of a bottlebrush or a scourer. The glassware is then thoroughly rinsed with hot water, and also with distilled water in the case of pipettes, burettes, volumetric flasks etc. Detergents are simple to use but very hard to remove. Abrasives, which scratch the glass, should not be used. Eye protection should be worn. (ii)

Using acid

A popular one used is chromic acid. RECIPE: l0g potassium dichromate is dissolved in 50mL water. Add concentrated sulfuric acid very slowly, stirring, until the volume is 200mL. Allow to stand for 10 minutes in a fume cupboard. Then add another 800mL concentrated sulfuric acid, constantly stirring and cooling in an ice bath. Pour chromic acid into empty, dirty glassware. Let it stand for 10 to 30 minutes, then chromic acid may be reused, but discard it when its colour is greenish. Note: If you splash chromic acid on your skin, wash it off immediately with plenty of water. This fluid will corrode skin and clothing, so protective clothing is essential when using it. CAUTION: Toxic; use gloves and fume cupboard. These are very useful if the material to be removed is known to be readily soluble in one or in a mixture of these solvents. The commonly used ones are: ethanol (alcohol), propanone (acetone), trichloromethane (chloroform), xylene, hexane and petroleum ether. Do not pour the latter three into the sink, but keep in bottles and discard with waste chemicals. (c)

Drying glassware after cleaning Alternative methods (i) Air-dry on racks; (ii) Rinse in ethanol (100%), propanone or ether and blow air through the vessel. (Note: ethanol, propanone and ether are highly flammable; all bunsens and gas heaters should be extinguished before using them); (iii) Beakers, pipettes, flasks etc. may be dried in an oven at 110 oC, after rinsing in water.

(d)

Washing and drying microscope slides and coverslips Soak slides in any one of the following solutions for 24 hours: chromic acid, concentrated sulfuric or concentrated nitric acid, equal parts of xylene and methylated spirits, detergent in water. Wash in running tap water. Rinse two or three times in distilled water.

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Store in acid alcohol. OR Rinse in water. Rinse in 95% alcohol. Wipe dry with a dry, clean, lint-free cloth. Coverslips are very much more fragile than microscope slides, therefore they should be washed in detergent in water and rinsed very carefully. It is best to store them in acid alcohol or in 70% alcohol and dry as needed. Coverslips used for smears or squashes should be discarded and not used again.

7.2.2

CONSTRUCTING AND PREPARING APPARATUS

A. Background Acquaintance with simple operations of basic woodworking and metalworking tools is often necessary. However, practical needs will differ according to the type of apparatus required, i.e. some apparatus will be constructed from basic materials, while other finished products will consist wholly or partially of assembled pre-constructed items. Building apparatus from raw materials will involve: (a) (b) (c)

a knowledge of the total design; the purpose of the assembled item; a knowledge of its possible uses, i.e. as a demonstration item, or for use by students.

B. Preparation Routine apparatus may often be prepared for future use. These items may be used singly or in combination to make more complicated apparatus. C. Examples of materials needed in an average school The scientific assistant's duties may include: (a) (b) (c) (d) (e) (f) (g)

preparation of lengths of insulated copper wire with bared ends, or with alligator clips screwed to the ends, or with 4 mm plugs attached to the ends; preparation of standard coils, using cardboard or polythene cylinders as the core; preparation of simple wood base-boards with terminals, for making simple circuits; preparations of lengths of wood for use as levers; the building of a framework to support pulley systems; the shaping of materials to make suitable inclined planes etc.; the assembly of atomic and molecular kits into a predetermined order. Some teachers prefer the pupils to do this. Hundreds of activities could be listed, but the partial assembly of materials, and the preparation of materials that will be needed in bulk are important aspects of the duties of a science assistant.

D. Collection of raw materials Sophisticated apparatus is often supplemented by materials gathered from everyday sources. The following is a list of the types of materials that may be gathered to be of use in experimentation and the assembly of apparatus: Acetate or cellophane squares, e.g. red; yellow, blue; agar jelly or gelatine; aluminium foil; balance-spring; bicycle pump; bottles; brass gauze; brass sheet; candles; cardboard squares; 147

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clothes pegs  wooden; copper wire; copper sheet; copper turnings; corks  assorted sizes; cork slab; drill  small hand; dry cells  torch; fibreglass or plastic or bronze mesh flyscreen; flannel or wool rags; forks  table; G-clamp  small; glass  drinking; hacksaw blades  coarse teeth; iron filings  from foundry; iron nails; iron sewing needles; iron wire  fencing gauge; lenses; marbles; mirrors; olive oil; ping-pong balls; pith material; plastic ruler; razor blades; rubber balloons; rubber bands  variety; rubber suction cups; silk pieces; silk thread; springs  ‘soft’; thermometers; wood screws and screw eyes; tin  with press-on lids, e.g. ice cream tins, or plastic containers; tin snips; cotton reels  wooden; metal pulley wheels  from hardware store; brass and iron pins; assorted hand tools; cardboard cylinders; chalk boxes; grease-proof paper; paste; plasticine. E. The preparation of sets of apparatus Sets of apparatus may be prepared for: (a) (b) (c)

consistent use in daily laboratory activities, e.g. glassware sets etc.; occasional use in demonstrations, or in rotation by student groups; or individual pupil use.

Therefore, some equipment may be issued from the store in the laboratory as permanent issue, while other equipment may be issued daily from stock. (a) (b)

(c)

Sets for everyday use, e.g. glassware, measuring devices, basic chemicals etc. These must be established and maintained as breakages and usages reduce the basic stock. Sets for demonstration. Basic materials, partially or wholly assembled equipment may be gathered and stored in a suitable location with a label showing the relevance of the material, e.g. physics apparatus for demonstrating the Bernoulli effect etc. Sets for issue. Many items are normally kept separate and assembled by the student as they are issued from the store, e.g. batteries, terminals and leads. However, student kits for particular experiments are frequently stored as complete sets. Materials from these sets should not be ‘borrowed’ for other experiments.

F. Concept boxes Materials that may be used to generate activities around basic concepts or generalisations can be placed together in suitable containers with the concept as the label. This concept may be broad or narrow and the concept box may be utilised by teacher or pupil, e.g. Physics  Electrostatics. G. General note Gathered and constructed apparatus that has limited use may be stored, or disassembled and the components stored. Many components may be used over and over to construct further apparatus. If a great deal of time has been invested in the construction of an item, it may best be stored in a safe place, or put on display for motivational purposes. Sometimes there is a temptation to keep apparatus that has taken a great deal of effort to construct, even if its use is very limited, or if it becomes redundant. In this case, it should not be retained.

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7.2.3 (a)

(b)

UNPACKING, CHECKING AND SORTING NEW EQUIPMENT As equipment arrives, it must be unpacked in a location that allows the materials to be set out and checked against the accompanying invoice. Any discrepancies or breakages should be noted and the supplier notified. Enter the quantity and date of receipt in the appropriate columns of the stock records.

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(c) (d)

(e)

7.2.4

Some materials will act as replacements while other items will need storage space assigned to them. It is desirable that items of ‘short life’, e.g. dry cells, be date-stamped before storage. This procedure is also useful with consumable stock such as chemicals, to reduce possible wastage of those chemicals that may deteriorate with storage. Annotation of the label, with a felt pen, of the year of supply of the item and storage of stock such as chemicals with oldest stock in front helps to reduce wastage. Items marked ‘to follow’ on invoices will be supplied when obtainable unless schools signify that they are no longer required.

STOCK CONTROL

Every science department must have two stockbooks, one for consumable chemicals and one for apparatus and other hardware. (In some laboratories an equivalent stock system may be in use.) On taking over a laboratory you must find and check the stockbooks to ensure: (a) (b)

that a stocktake was done in the previous year; that the stock as listed is correct.

This procedure also ensures that you know what resources you have. (a)

(b)

(c) (d)

(e)

Always put equipment or chemicals away as soon as possible after use and have a designate d place for each type of item. Leaving equipment out on benches invites pilfering or breakage. Keep a breakage book in the science room and enter all breakages as soon as practicable after they occur. This is essential if you are to account for all apparatus at the next stocktake. When new stock arrives, enter the quantity and the date of receipt in the appropriate columns in the stock records. Some equipment will be on Edquip cards. This equipment and the relevant card numbers should also be recorded on a separate page in the stockbook. Equipment which is to be processed through Edquip is marked with an asterisk on the stock order sheets issued by the Education Department from 1979 onwards. Broken or unserviceable equipment other than glassware, rubber stoppers and tubing, or plastic ware, should be put to one side. When stock is being taken, all equipment should be inspected by the stocktaker and any damaged, unserviceable or potentially dangerous equipment put aside. This is especially necessary with equipment handled by students. Test tube holders, beaker tongs, asbestos mats and stands should all be checked, and new ones ordered if any are defective, while under no circumstances should chipped or cracked glassware be allowed to remain in use.

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7.2.5

RAZOR BLADES

Single-edged razor blades (e.g. Gem brand) should be used instead of the normal double-edged ones. (Alternatively use a holder.) Students will find single -edged blades easier to use, and they are less likely to cut themselves.

7.2.6

USING A GAS-PAK

The Gas-Pak consists of a bunsen burner connected to a small disposable can of gas.

INSTRUCTIONS FOR USE

(a)

Remove cap from can. With the control knob in the ‘off’ position, push the plug-in valve firmly onto the can.

(b)

Close the sleeve holes. Light a match. Turn the control knob slowly to the ‘on’ position until gas flows. Light the burner. Adjust the gas control knob and sleeve on the bunsen burner.

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PROBLEMS (a)

(b)

If the flame is poor you should: • check the gas content of the can; • check that the plug-in valve is seated correctly; or • adjust the gas control knob. If the flame is still poor, turn off the gas and wait for the burner to cool. Unscrew the burner head and turn on the gas. Use the jet pricker wire (supplied with the burner) to clear the jet by inserting the pricker wire into the jet hole and moving it up and down until the jet is clear and the gas flow is normal. Relight the burner as above.

DO’S AND DON’TS (a) Use the burner only in a draught-free area. (b) Always keep the can upright when the burner is alight. (c) Check any warnings on the can. (d) Allow the burner to cool before you move or store it. (e) Dispose of can properly, i.e. do not puncture or incinerate it. (f) Never turn the gas on without lighting the burner (gas forms an explosive mixture in air). (g) Low melting point objects (e.g. plastics, solder, lead) should not be heated directly over the barrel of the burner. (Melted pieces may fall inside the barrel). Instead, hold the burner on an angle, as shown.

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7.2.7 MAKING A CANDLE IN A HOLDER

Method A  for long candles Place candle in can, and then fill with sand. As the candle burns down, the can may be shortened with scissors. When the candle is too short to be held by this method, use Method B.

Method B  for short candles (no longer than diameter of lid)

DO’S AND DON’TS (a) (b)

Make sure the candle is secure in its plasticine base and that the candle cannot tip over. Allow the candle to cool before you move or store it, as hot wax can burn.

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7.2.8

LIGHTING THE BUNSEN BURNER

7.2.9

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7.2.9

USING BUNSEN BURNERS

TEST TUBE

TRIPOD STAND AND GAUZE MAT

STAND AND CLAMP

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ADJUSTING THE FLAME

Blue flame • hard to see • very hot • used when trying to heat an object quickly or when high temperature required, e.g. when heating coal

Yellow flame • easy to see • not as hot as blue flame • leaves black soot deposits on glassware • used if burner is alight and awaiting use

You can also control the burner flame by partially closing the gas cock. DO’S AND DON’TS (a) (b) (c) (d) (e)

Turn gas off at gas cock first, then at the cylinder. Use the burner only in a draught-free area. Allow the burner to cool before you move or store it. Never turn the gas on without lighting the burner (gas forms an explosive mixture in air). Low melting point objects (e.g. plastics, solder, lead) should not be heated directly over the barrel of the burner. (Melted pieces may fall inside the barrel.) Instead, hold the burner on an angle, as shown.

PROBLEMS (a)

(b)

Match blown out. • Turn gas off. • Start from Step 5 to relight the burner. Blow back (or strike back)  this means the gas is burning inside the barrel of the burner. • Turn gas off. • Allow to cool  barrel could be extremely hot. • Start from Step 5 to relight burner.

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7.2.10 GLASSWARE CUTTING TUBING (a) Place the tube flat on the table. Measure the required length. Hold the tube firmly and draw a triangular file across it a couple of times so that a scratch is made. Do not saw back and forth. (One or two firm cuts is usually sufficient.) (b) Take the tube in both hands, one each side of the scratch, as shown. Keep your thumbs as close as possible to the scratch. Press gently with your thumbs and pull with your fingers. The two pieces of tubing should separate. Brute strength is not needed. If the tube does not break easily, make the file scratch a little deeper and longer. (c) Light the burner, and open the air hole. This gives a hot blue flame. Warm one end of the tubing by passing it through the flame a few times. When the tubing is warm, rotate the end of the tube in the flame until the glass begins to turn yellow and melt a little. Keep rotating the tube until the rough edges become smooth. Do not heat too much and do not stop rotating. Place the hot glass on a gauze mat to cool. The end is now fire-polished. (d) When the tube is cool, fire-polish the other cut end. Again allow to cool. (e) Make sure all broken glass is put in a special labelled container  not in the waste paper basket. BENDING TUBING (a) Light the burner and open the air hole. This gives a hot blue flame. Using both hands, move the tube back and forth through the top of the flame. At the same time rotate the tube. Heat about 5 centimetres of tube. (b) When the tubing is warm, lower it into the dark blue cone of the flame. Keep rotating the tube until it glows red and you sense that the tube has become soft.

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(c) Take the tube out of the flame and bend it. Do not force it, and once you have bent it, do not reheat it. (d) Hold the tubing until it cools a little. Then put it on the gauze mat to cool further. (e) Poor bends.

7.2.11 PUTTING TUBING INTO A STOPPER Note: This can be a rather hazardous operation, and should never be done by students. The stopper with glass tubing inserted should be kept for any future use. (a) Check that the tubing will fit into the one-holed stopper. Also check that the ends of the tubing are properly fire-polished with no sharp edges. (b) Wet the tube and the stopper with water containing a little detergent. This makes them slippery, and it is easier to get the tube through the stopper. (c) Use the cloth to hold the tube firmly. Place a leather gardening glove on the hand which will hold the stopper. Then slowly rotate the stopper onto the tube. Keep wetting the stopper and tubing so that the tube slides easily. Under no circumstances should you hold the palm of your hand over the end of the tube. (d) To remove the tubing from the stopper it is probably safest to cut the stopper.

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7.2.12 THERMOMETERS The thermometers presently supplied to schools usually contain alcohol and not mercury. Where possible, avoid leaving thermometers in containers as shown, where they are easily knocked by students. If you wish to monitor the temperature continuously then it is advisable to clamp the thermometer in position. If students are recording the temperature at regular intervals (say 5 minutes), then the thermometer should be returned to its case between measurements. To put a thermometer into a stopper, you should first cut the stopper. Under no circumstances should normal thermometers be placed in students’ mouths. Do not use thermometers to stir liquids. Sometimes the liquid in a thermometer will separate, making it unusable. This problem can usually be solved by placing the thermometer in a refrigerator freezer until the liquid recombines. Do not try to recombine the liquid by heating the thermometer (it may explode!).

7.2.13 DANGERS FROM THE SUN There are several dangers with activities associated with sunlight. (a) Students must never look directly at the sun. (b) If students are going to be in the sun for any length of time, they should wear a hat. (c) Do not use direct sunlight to illuminate a microscope. Use a low watt lamp bulb, e.g. 25 watt or 40 watt. The bulb should also be pearl not clear. Direct sunlight reflected in microscope mirrors can cause eye damage to the eye. If you need to use sunlight, have the children set up the microscope in a bright position near the windows but not in direct sunlight. (d) Children must not watch a solar eclipse directly, or even through welding goggles or similar. Use a pin hole system as shown.

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8.

GLOSSARY Term

Simple meaning

Acids

Compounds that contain hydrogen and dissociate in water to produce positive hydrogen ions.

Acid anhydride

Compounds that react with water to form an acid.

Alkali

A soluble lease: it forms hydroxide ions in solution.

Alternating current (AC)

Current that flows first in one direction and then in the other.

Ampere

The quantity of electric current flow ing every second.

Anode

The positive electrode of an electrolytic cell.

Atmospheric corrosion

A reaction between a metal and oxygen and water in the air; rusting is an example.

Autoclaving

A strong closed vessel in which steam under pressure effects sterilisation.

Buffer

Maintains the acidity or alkalinity of a solution.

Cathode

The negative electrode of an electrolytic cell.

Circuit breaker compound`

A substance made up of several different elements combined together in definite proportions.

Carbonates

A salt of carbonic acid (CO 32- ). Carbonates react with mineral acids to release carbon dioxide.

Conduction

The process in which energy (usually heat or electrical) flows through a substance.

Conductor

A substance that readily conducts heat, electricity, sound, etc.

Conjugate

Two species related by loss or gain of a proton.

Convection

The transfer of heat in a fluid (or gas) by the movement of the fluid itself.

Corrosion

Chemical or electrochemical attack on the surface of a metal.

Current (A)

The rate of flow of electricity, measured in amperes.

Deflagrating spoon

A spoon used for heating small quantities by concentrating the heat.

Desiccator

A container for drying substances or keeping them free from moisture.

Diffusion

A process in which particles move from a high concentration.

Diode

An electronic component that allows current to flow in one direction only.

Direct current (DC)

An electric current that flows in one direction only.

Distillation

The process of evaporating a liquid and then condensing the vapour in a separate container.

Electric charge

An amount of electricity: there are two kinds of charges - positive and negative.

Electric circuit

A complete path around which an electric current can flow.

Electrical conductor

A substance that allows electricity to move through it.

Electrical resistance

The opposition of a substance to electricity passing through it.

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Term

Simple meaning

Element

A substance made up of only one type of atom: it cannot be broken into simpler substances by chemical reaction.

Emaciation

Gradual wasting away resulting in abnormal thinness caused by lack of nutrition.

Fixative

The chemical used in the first stage in the preparation of a microscope specimen in which the tissue is killed and preserved in a natural state.

Flammable substance

A substance that is easily set on fire.

Formula

An abbreviation using chemical symbols, which tells you which elements are in a compound, and the ratio of these elements

Energy

A measure of the capacity to do work, measured in joules (J).

Frict ion

A force that occurs whenever two things rub together.

Exothermally

Releases heat.

Hazardous substance

A substance which may cause risk, danger or harm. (Non-technical definition.)

Ingestion

To put or take into the body.

Inorganic

Compounds containing elements other than carbon. Certain simple carbon compounds such as carbon monoxide and carbonates are usually treated as inorganic compounds.

Insulator

A substance that does not allow electricity to move through it.

Ion

An atom or group of atoms that has either lost one or more electrons (positively charged) or gained one or more electrons (negatively charged).

Milliamperes

Ampere is the SI base unit of electric current therefore milliampere is one thousandth of an ampere.

Molar

A unit of measurement for concentration.

Molecule

A particle containing several atoms joined together, always in the same ratio.

Nitrile

Organic compounds containing the group -CN bound to an organic group.

Organic

Compounds containing carbon.

Oxidising agent

A substance that brings about oxidation in other substances. In oxidising other substances, these atoms gain electrons.

Parallel circuit

An electric circuit in which the parts are connected in parallel to one another.

Parasitic worms

Either round-worms or flat-worms that live in the body of another living organism (the host): often the host suffers a disease because of the parasite.

Pathogenic

Disease producing.

Petroleum products

A naturally occurring oil that consists chiefly of hydrocarbons. The main fractions are gases (methane, ethane, butane, propane), gasoline, kerosine, diesel oil, lubricating oils, paraffin wax and bitumen.

pH

A measure of acidity.

Phenolics

Organic compounds that contain a hydroxyl group (-OH) bound directly to a carbon atom in a benzene ring.

Potential difference

Energy which is stored up, ready to be used, measured in joules (J).

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Term

Simple meaning

Preserving

Preparing or maintaining perishable substances so as to resist decomposition or fermentation.

Psychoses

Severe form of mental affection.

Radiation

Energy that can pass through space or through the air that moves as waves, rays or a stream of particles.

Resistance

The more resistance a wire has, the less current it can carry. Resistance is measured in ohms.

Series circuit

An electric circuit in which the parts are connected one after the other.

Solvents

Liquids that dissolve other substances.

Staining

A technique in which cells or thin sections of biological tissue that are normally transparent are immersed in one or more coloured dyes.

Symbol

An abbreviation of one or two letters that stands for the name of an element.

Toxins

Poisons given off by microorganisms.

Transformer

A device for transferring electrical energy from one alternating-current circuit to another with a change of voltage, current, phase, or impedance.

Volt (V)

One volt is the force needed to carry one ampere of current against one ohm of resistance.

Weal

A small burning or itching swelling on the skin as from a mosquito bite.

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