Pengurusan Makmal Sains 9
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UNIT 9 : PRACTICAL MANAGEMENT
UNIT 9 – PRACTICAL MANAGEMENT IN LABORATORY SCIENCE Concept mapping Practical management in laboratory science
Glass working skills
9.1
Working with electricity
The proper technique of transferring liquids
Objective 9.1.1
To examine the best teaching strategy during practical session
9.1.2 Learn to handle glass apparatus and electrical equipment 9.2
Introduction When the experienced laboratory worker recalls his early days in the laboratory he may
wonder how in spite of his inexperience he manage d to avoid a serious accident. As in all arts and craft it is the younger worker who has the most need of careful guidelines, training and management during the experiment. A sound of spirit of co-operation and inselfshness on the part of all the laboratory staff is the best safeguard against accidents. The most important steps to safety are cleanliness and tidiness, which in themselves promote an accident free environment. Cultered benches not only couses a accident but clearly indicate muddled working on the part of the person responsible. Inadequate locker and storage arrangement may contribute to this state of affairs.
101
UNIT 9 : PRACTICAL MANAGEMENT
To supplement the work of the safety officer, all personnel should received training in first aid and this connection the various Red Cross Organisation are usually willing to lend assistance. Every encouragement should be given to staff to see potential hazards and to recording accidents can assure their prevention.
9.3
Glass Working Skills Teachers and laboratory staff will find the ability to perform simple glass manipulations a
great help in preparing simple glass apparatus and making simple repairs.
9.3.1
Condition for Glass Working 9.3.1.1 Temperature A room temperature of about 25 Celsius is usually found suitable. A higher room temperature or working temperature is acceptable. However, a very low room temperature is often not suitable for glass working. The most important factor is an area free from draughts. Draughts cause premature cooling in parts of heated glass and this leads to fractures, and can cause the flame to flicker. This would mean that a steady heat source would not be available. 9.3.1.2 Bench
101
UNIT 9 : PRACTICAL MANAGEMENT
The bench must be covered with a sheet of asbestos. The bench must be of such a height that with an appropriate sized stool provided, the worker can sit neatly and comfortably, easily resting his feet on the floor and his elbows on the bench. It should be suitably strong. Along the back and ends should be fixed a wood edging some 5 cm high. This will not only prevent work and tools from rolling off the bench, but will support glass parts put down to cool. A nest of small drawers at the right hand, under the bench, will be found very convenient for storage of small tools and odds and ends. 9.3.1.3 Lighting The flame used is normally or usually almost non-luminous. In bright sunlight this cannot be seen, and burns may result. The lighting should be subdued so that the flame and the color of the glass can be seen. 9.3.1.4 Waste box In normal working conditions much glass is broken. A large biscuit tin serves well for disposal of broken pieces. Great care must be taken in clearing glass off benches. This is best done by using a small brush and sweeping the pieces directly into the box. Alternatively a small brush pan is useful. 9.3.1.5 Tools 9.3.1.6 Burner
101
UNIT 9 : PRACTICAL MANAGEMENT
If work on soda-lime glass is only contemplated the laboratory Bunsen flame or spirit flame should be used. However, if borosilicate glass is used an air or oxygen blowpipe is required. The blowpipe is a burner which produces a very hot flame from a mixture of oxygen and gas. The amount of air or oxygen and gas can be very carefully controlled. Reference should be made to supplier’s catalogues before buying and the type of gas being used should be mentioned before making an order for a burner. Glass-cutting knife; The tool should be kept in good condition. After use it should be dipped in an oil-kerosene mixture and wrapped in an oily rag. A number of triangular files. These are useful for cutting glass especially glass tubing.
9.4
Working with Electricity 9.4.1 Electrical Wiring The insulation of wires must be removed before any connection can be made. This made of rubber which can be removed with a knife, a pair of sidecutting pliers or a special ‘wire stripper’. Avoid nicking the wire or it will easily break. In the case of enameled wire all insulation must be removed. The enamel coat can be scrapped off by using pen-knife or sandpaper. It can also be removed by applying flame over it. For bare wires the ends should be scrapped clean or rubbed with sandpaper to ensure a proper contact. About 2cm of insulation should be removed to make a proper loop to fit around a terminal screw. 101
UNIT 9 : PRACTICAL MANAGEMENT
Single strand wire should simply be looped and screwed so that each turn of the screw tends to tighten the loop. The round shaft of a screw-driver can be used to form the hook or loop. Multi-strand wire must be twisted together. The strands can also be bound together using solder. This is especially suitable for permanent sets of wire. 9.4.2
Wiring a 3-Pin Plug A typical 3-pin plug is explained as below. The earth pin is usually the largest of the three pins and is always placed or situated at the top. The earth wire (green-yellow stripes) runs along the centre of the plug for connection to the earth pin. The live or phase wire (brown) is connected to the right-hand pin. The fuse is fixed or connected to this pin.
The neutral wire (blue) is connected to
the left-hand pin. The old color code was earth- green; phase (live) - red and neutral- black. Care should be taken to ensure that all connections are correctly and firmly connected. In a two-pin plug, the earth pin is absent. The live and neutral wires are similarly connected as that described above for a three-pin plug.
3-Pin plug
9.5
Working with Chemical Reagent 102
UNIT 9 : PRACTICAL MANAGEMENT
Most of chemical reactions studied in the laboratory are the reactions that are in solution form. Working with chemical reagents should not be taken granted. There are various techniques involves in the operations. Some are so simple that they should always be put into practice. It is only by doing the right way that accidents are avoided. Solution often must be prepared in fairly large quantities so that they can last for few weeks or months depending on the kind of solution. Indicator solutions may last for a year or more. Containers holding these solutions should be labeled and their labels should be checked from time to time. Quite a number of solutions are best stored in big plastic containers that can hold from 1 to 3 litres. These are called bench or stock solutions. Plastic containers offer a number of advantages over other types of containers. Solutions in translucent plastic containers can be seen. Such containers can reduce breakage and can withstand shock. For opaque plastic containers, the quantity of solutions can be estimated by holding the containers against the light source. A dispenser can easily be attached to a big plastic container which may then serve as an aspirator. To convert a large plastic container to an aspirator select a nail which is a little smaller than a glass or plastic tubing which will be inserted into the container. Heat the nail and bore a hole near the bottom of the container where we are going to put the tubing. Insert the glass tube or plastic tubing into the hole. Put a good brand of epoxy glue to join it. Attach a tap for control. For student use supply bottles of solutions should be fairly small. 250 ml reagent bottles are suitable for labeling as they are easily handled by students. For small-scale or semi-micro work, much smaller quantities of solutions can be used. Small plastic squeeze bottles (of say 100 ml) can be used to disperse small amount of liquid. This type of container minimizes spillage and wastage of chemicals. All supplied bottles of stock solutions should be properly labeled. Plastic
102
UNIT 9 : PRACTICAL MANAGEMENT
containers are best labeled by a wax pencil, laundry marking pen or a dry marker as the markings are waterproof. Stoppers of reagent bottles should fit properly. Glass reagent bottles for alkaline solutions must have rubber or plastic stoppers. Alkaline substances may react with carbon dioxide in the atmosphere forming carbonates. Glass stoppers are difficult to remove because the carbonates set like cement between the stopper and the bottle. Indicators are best stored in dropper bottles. This prevents the contamination of solutions. Containers of indicators can be made out of baby food ars or disposable plastic squeeze bottles. The centre of a baby food jar cover can be pierced with a big nail to make a hole for a dropper. To avoid evaporation the dropper should fit well into the cover. Glue may be put at the contact of dropper and stopper if a wider hole had been made.
9.7
The Proper Technique of Transferring Liquids from a Reagent Bottle to a
Container 9.7.1
Check the label of the bottle to see whether it contains the correct solution.
9.7.2
Remove the stopper and hold it between little finger and edge of hand.
9.7.3
Grasp the bottle on the labeled side to ensure that no liquid is spilled over the label.
9.7.4
Pour the solution. Make sure to get the last drop by allowing the lip of the bottle to touch the container.
9.7.5
Replace the stopper.
9.7.6
Return the reagent bottle to its original place. Read the label again to make sure the correct chemical was taken.
102
UNIT 9 : PRACTICAL MANAGEMENT
9.7.7
When measuring bigger volumes of solutions calibrated glassware is needed. Examples of calibrated glassware are the burettes, graduated cylinders and flasks. To read correct volumes, hold at eye level and read the lower curve of the liquid (called meniscus)
9.9 Conclusion As a whole, this part is important part where practical is carried out by the students. This part is important because it will determine the goals of practical curriculum.
Question 1. Which these are the components of The Science National Curriculum that are using as guide for build the content of curriculum by curriculum maker? I skills and process of scientific inquiry IIknowledge of what science is and how scientist interact with each other and society IIIknowledge of scientific laws, theory and concepts IVall the answer are incorrectly
A I and II B II and III C I, II and III D I, II, III and IV 101
UNIT 9 : PRACTICAL MANAGEMENT
1. These are the important of science curriculum for the students except? A
Knowledge o help students understand the basis for decisions in an increasingly technology world
B
Give bad implication for people of all nations
C
The problems students can develop investigative and practical skills which can help them to solve
D
Helps students make sense of natural phenomena
3. Four important aspects that included in education courses? A
Teachers, learners, subject matter and context
B
Learners, students, context and subject matter
C
Context, subject matter, school and learners
D
Subject matter, parents, teachers and context
4. The element science methods including? I
Characterization
II Prediction III Hypotheses development IV Experiments
A
I and II
B
II and III 102
UNIT 9 : PRACTICAL MANAGEMENT
5.
C
I, II and III
D
I, II, III and IV
What should we have the element of characterizations in every experimental?
5.
A
To make students more thinking
B
to make sure the students will get the correct result of the experiments
C
just follow the guide
D
all above incorrectly
These below the important aspect which have in hypothesis development element, except? I
Theoretical
II Hypothetical explanation III Measurements of the subject IV Manipulative skills
A
I, II and III
B
II, III and IV
C
I,III and IV
D
Only IV
5. What the implication if the predictions are not accessible by observation or experience? 101
UNIT 9 : PRACTICAL MANAGEMENT
A. Never give the negative impact. B. The result is still going be positive C. Its not affect the whole of the experiment D. the hypothesis is not yet useful for the method
6. From the science curriculum model, what is disadvantage from it? A. The curriculum guide the teachers how to plan a lesson planning B. The model will make the teachers being systematically in teaching process C. The model relied on a rather theoretical and technical approach without reference to practical consideration D. The students will easy to learn from the structural learning process
7. Why the science curriculum models give disadvantage for us? I
There was no representation of curriculum or instruction the realities
II The curriculum and instruction in learning outcomes were unclear III The student was not represented in the model but learning outcomes were shown. IV All above are correctly
A I, and II B II and III C I and III D I, II, III and IV
101
UNIT 9 : PRACTICAL MANAGEMENT
5. Why many prospective science teachers have not such experience and need to rely on curriculum guides? I
They have no many experience when they are in universities
II They did not get more real experience during study III The teachers lack of knowledge IV The teachers are lack of attitude
A I, and II B II and III C I , II and III D I, II, III and IV Answer 1. D 2. D 3. D 4. B 5. B 6. D 7. B 8. C 9. D 10. D
References Amritage, Philip and Fasemore, Johnson. (1977). Laboratory Safety: A Science Teacher’s Source Book, Heinamann Education Books, London. Chisman, Dennis (1987) Preliminary Issues, Practical Secondary Education: Planning for Cost- Effectiveness in less Developed Countries, Commonwealth Secreteriat, London. Fahkru’l-Razi Ahmadun, Chuah Teong Guan and Mohd Halim Shah. 2005. Safety: Principles & Practices in the Laboratory, Penerbit Universiti Putra Malaysia, Serdang.
101
UNIT 9 : PRACTICAL MANAGEMENT
Hegarty-Hazel, Elizabeth (1990), The Student Laboratory and the Science Curriculum: An Overview, The Student Laboratory and the Science Curriculum, pt.1, pg.3. McGrath, Dennis M. (1978), Some General Considerations, Laboratory Management and Techniques For School and Colleges, Anthonian, Kuala Lumpur-Ipoh-Singapore. Woolnough, Brian E. (1991). Setting the scene, Practical Science, pt.1, pg.6. Woolnough, Brian E. (1991). Setting the scene, Practical Science, pt.1, pg. 13. Woolnough, Brian E. (1991). Setting the scene, Practical Science, pt.1, pg. 14. K. Guy. Laboratory organization and administration. London Butterworths
102
UNIT 9 – PRACTICAL MANAGEMENT IN LABORATORY SCIENCE Concept mapping Practical management in laboratory science
Glass working skills
9.1
Working with electricity
The proper technique of transferring liquids
Objective 9.1.1
To examine the best teaching strategy during practical session
9.1.2 Learn to handle glass apparatus and electrical equipment 9.2
Introduction When the experienced laboratory worker recalls his early days in the laboratory he may
wonder how in spite of his inexperience he manage d to avoid a serious accident. As in all arts and craft it is the younger worker who has the most need of careful guidelines, training and management during the experiment. A sound of spirit of co-operation and inselfshness on the part of all the laboratory staff is the best safeguard against accidents. The most important steps to safety are cleanliness and tidiness, which in themselves promote an accident free environment. Cultered benches not only couses a accident but clearly indicate muddled working on the part of the person responsible. Inadequate locker and storage arrangement may contribute to this state of affairs.
101
UNIT 9 : PRACTICAL MANAGEMENT
To supplement the work of the safety officer, all personnel should received training in first aid and this connection the various Red Cross Organisation are usually willing to lend assistance. Every encouragement should be given to staff to see potential hazards and to recording accidents can assure their prevention.
9.3
Glass Working Skills Teachers and laboratory staff will find the ability to perform simple glass manipulations a
great help in preparing simple glass apparatus and making simple repairs.
9.3.1
Condition for Glass Working 9.3.1.1 Temperature A room temperature of about 25 Celsius is usually found suitable. A higher room temperature or working temperature is acceptable. However, a very low room temperature is often not suitable for glass working. The most important factor is an area free from draughts. Draughts cause premature cooling in parts of heated glass and this leads to fractures, and can cause the flame to flicker. This would mean that a steady heat source would not be available. 9.3.1.2 Bench
101
UNIT 9 : PRACTICAL MANAGEMENT
The bench must be covered with a sheet of asbestos. The bench must be of such a height that with an appropriate sized stool provided, the worker can sit neatly and comfortably, easily resting his feet on the floor and his elbows on the bench. It should be suitably strong. Along the back and ends should be fixed a wood edging some 5 cm high. This will not only prevent work and tools from rolling off the bench, but will support glass parts put down to cool. A nest of small drawers at the right hand, under the bench, will be found very convenient for storage of small tools and odds and ends. 9.3.1.3 Lighting The flame used is normally or usually almost non-luminous. In bright sunlight this cannot be seen, and burns may result. The lighting should be subdued so that the flame and the color of the glass can be seen. 9.3.1.4 Waste box In normal working conditions much glass is broken. A large biscuit tin serves well for disposal of broken pieces. Great care must be taken in clearing glass off benches. This is best done by using a small brush and sweeping the pieces directly into the box. Alternatively a small brush pan is useful. 9.3.1.5 Tools 9.3.1.6 Burner
101
UNIT 9 : PRACTICAL MANAGEMENT
If work on soda-lime glass is only contemplated the laboratory Bunsen flame or spirit flame should be used. However, if borosilicate glass is used an air or oxygen blowpipe is required. The blowpipe is a burner which produces a very hot flame from a mixture of oxygen and gas. The amount of air or oxygen and gas can be very carefully controlled. Reference should be made to supplier’s catalogues before buying and the type of gas being used should be mentioned before making an order for a burner. Glass-cutting knife; The tool should be kept in good condition. After use it should be dipped in an oil-kerosene mixture and wrapped in an oily rag. A number of triangular files. These are useful for cutting glass especially glass tubing.
9.4
Working with Electricity 9.4.1 Electrical Wiring The insulation of wires must be removed before any connection can be made. This made of rubber which can be removed with a knife, a pair of sidecutting pliers or a special ‘wire stripper’. Avoid nicking the wire or it will easily break. In the case of enameled wire all insulation must be removed. The enamel coat can be scrapped off by using pen-knife or sandpaper. It can also be removed by applying flame over it. For bare wires the ends should be scrapped clean or rubbed with sandpaper to ensure a proper contact. About 2cm of insulation should be removed to make a proper loop to fit around a terminal screw. 101
UNIT 9 : PRACTICAL MANAGEMENT
Single strand wire should simply be looped and screwed so that each turn of the screw tends to tighten the loop. The round shaft of a screw-driver can be used to form the hook or loop. Multi-strand wire must be twisted together. The strands can also be bound together using solder. This is especially suitable for permanent sets of wire. 9.4.2
Wiring a 3-Pin Plug A typical 3-pin plug is explained as below. The earth pin is usually the largest of the three pins and is always placed or situated at the top. The earth wire (green-yellow stripes) runs along the centre of the plug for connection to the earth pin. The live or phase wire (brown) is connected to the right-hand pin. The fuse is fixed or connected to this pin.
The neutral wire (blue) is connected to
the left-hand pin. The old color code was earth- green; phase (live) - red and neutral- black. Care should be taken to ensure that all connections are correctly and firmly connected. In a two-pin plug, the earth pin is absent. The live and neutral wires are similarly connected as that described above for a three-pin plug.
3-Pin plug
9.5
Working with Chemical Reagent 102
UNIT 9 : PRACTICAL MANAGEMENT
Most of chemical reactions studied in the laboratory are the reactions that are in solution form. Working with chemical reagents should not be taken granted. There are various techniques involves in the operations. Some are so simple that they should always be put into practice. It is only by doing the right way that accidents are avoided. Solution often must be prepared in fairly large quantities so that they can last for few weeks or months depending on the kind of solution. Indicator solutions may last for a year or more. Containers holding these solutions should be labeled and their labels should be checked from time to time. Quite a number of solutions are best stored in big plastic containers that can hold from 1 to 3 litres. These are called bench or stock solutions. Plastic containers offer a number of advantages over other types of containers. Solutions in translucent plastic containers can be seen. Such containers can reduce breakage and can withstand shock. For opaque plastic containers, the quantity of solutions can be estimated by holding the containers against the light source. A dispenser can easily be attached to a big plastic container which may then serve as an aspirator. To convert a large plastic container to an aspirator select a nail which is a little smaller than a glass or plastic tubing which will be inserted into the container. Heat the nail and bore a hole near the bottom of the container where we are going to put the tubing. Insert the glass tube or plastic tubing into the hole. Put a good brand of epoxy glue to join it. Attach a tap for control. For student use supply bottles of solutions should be fairly small. 250 ml reagent bottles are suitable for labeling as they are easily handled by students. For small-scale or semi-micro work, much smaller quantities of solutions can be used. Small plastic squeeze bottles (of say 100 ml) can be used to disperse small amount of liquid. This type of container minimizes spillage and wastage of chemicals. All supplied bottles of stock solutions should be properly labeled. Plastic
102
UNIT 9 : PRACTICAL MANAGEMENT
containers are best labeled by a wax pencil, laundry marking pen or a dry marker as the markings are waterproof. Stoppers of reagent bottles should fit properly. Glass reagent bottles for alkaline solutions must have rubber or plastic stoppers. Alkaline substances may react with carbon dioxide in the atmosphere forming carbonates. Glass stoppers are difficult to remove because the carbonates set like cement between the stopper and the bottle. Indicators are best stored in dropper bottles. This prevents the contamination of solutions. Containers of indicators can be made out of baby food ars or disposable plastic squeeze bottles. The centre of a baby food jar cover can be pierced with a big nail to make a hole for a dropper. To avoid evaporation the dropper should fit well into the cover. Glue may be put at the contact of dropper and stopper if a wider hole had been made.
9.7
The Proper Technique of Transferring Liquids from a Reagent Bottle to a
Container 9.7.1
Check the label of the bottle to see whether it contains the correct solution.
9.7.2
Remove the stopper and hold it between little finger and edge of hand.
9.7.3
Grasp the bottle on the labeled side to ensure that no liquid is spilled over the label.
9.7.4
Pour the solution. Make sure to get the last drop by allowing the lip of the bottle to touch the container.
9.7.5
Replace the stopper.
9.7.6
Return the reagent bottle to its original place. Read the label again to make sure the correct chemical was taken.
102
UNIT 9 : PRACTICAL MANAGEMENT
9.7.7
When measuring bigger volumes of solutions calibrated glassware is needed. Examples of calibrated glassware are the burettes, graduated cylinders and flasks. To read correct volumes, hold at eye level and read the lower curve of the liquid (called meniscus)
9.9 Conclusion As a whole, this part is important part where practical is carried out by the students. This part is important because it will determine the goals of practical curriculum.
Question 1. Which these are the components of The Science National Curriculum that are using as guide for build the content of curriculum by curriculum maker? I skills and process of scientific inquiry IIknowledge of what science is and how scientist interact with each other and society IIIknowledge of scientific laws, theory and concepts IVall the answer are incorrectly
A I and II B II and III C I, II and III D I, II, III and IV 101
UNIT 9 : PRACTICAL MANAGEMENT
1. These are the important of science curriculum for the students except? A
Knowledge o help students understand the basis for decisions in an increasingly technology world
B
Give bad implication for people of all nations
C
The problems students can develop investigative and practical skills which can help them to solve
D
Helps students make sense of natural phenomena
3. Four important aspects that included in education courses? A
Teachers, learners, subject matter and context
B
Learners, students, context and subject matter
C
Context, subject matter, school and learners
D
Subject matter, parents, teachers and context
4. The element science methods including? I
Characterization
II Prediction III Hypotheses development IV Experiments
A
I and II
B
II and III 102
UNIT 9 : PRACTICAL MANAGEMENT
5.
C
I, II and III
D
I, II, III and IV
What should we have the element of characterizations in every experimental?
5.
A
To make students more thinking
B
to make sure the students will get the correct result of the experiments
C
just follow the guide
D
all above incorrectly
These below the important aspect which have in hypothesis development element, except? I
Theoretical
II Hypothetical explanation III Measurements of the subject IV Manipulative skills
A
I, II and III
B
II, III and IV
C
I,III and IV
D
Only IV
5. What the implication if the predictions are not accessible by observation or experience? 101
UNIT 9 : PRACTICAL MANAGEMENT
A. Never give the negative impact. B. The result is still going be positive C. Its not affect the whole of the experiment D. the hypothesis is not yet useful for the method
6. From the science curriculum model, what is disadvantage from it? A. The curriculum guide the teachers how to plan a lesson planning B. The model will make the teachers being systematically in teaching process C. The model relied on a rather theoretical and technical approach without reference to practical consideration D. The students will easy to learn from the structural learning process
7. Why the science curriculum models give disadvantage for us? I
There was no representation of curriculum or instruction the realities
II The curriculum and instruction in learning outcomes were unclear III The student was not represented in the model but learning outcomes were shown. IV All above are correctly
A I, and II B II and III C I and III D I, II, III and IV
101
UNIT 9 : PRACTICAL MANAGEMENT
5. Why many prospective science teachers have not such experience and need to rely on curriculum guides? I
They have no many experience when they are in universities
II They did not get more real experience during study III The teachers lack of knowledge IV The teachers are lack of attitude
A I, and II B II and III C I , II and III D I, II, III and IV Answer 1. D 2. D 3. D 4. B 5. B 6. D 7. B 8. C 9. D 10. D
References Amritage, Philip and Fasemore, Johnson. (1977). Laboratory Safety: A Science Teacher’s Source Book, Heinamann Education Books, London. Chisman, Dennis (1987) Preliminary Issues, Practical Secondary Education: Planning for Cost- Effectiveness in less Developed Countries, Commonwealth Secreteriat, London. Fahkru’l-Razi Ahmadun, Chuah Teong Guan and Mohd Halim Shah. 2005. Safety: Principles & Practices in the Laboratory, Penerbit Universiti Putra Malaysia, Serdang.
101
UNIT 9 : PRACTICAL MANAGEMENT
Hegarty-Hazel, Elizabeth (1990), The Student Laboratory and the Science Curriculum: An Overview, The Student Laboratory and the Science Curriculum, pt.1, pg.3. McGrath, Dennis M. (1978), Some General Considerations, Laboratory Management and Techniques For School and Colleges, Anthonian, Kuala Lumpur-Ipoh-Singapore. Woolnough, Brian E. (1991). Setting the scene, Practical Science, pt.1, pg.6. Woolnough, Brian E. (1991). Setting the scene, Practical Science, pt.1, pg. 13. Woolnough, Brian E. (1991). Setting the scene, Practical Science, pt.1, pg. 14. K. Guy. Laboratory organization and administration. London Butterworths
102
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