Chapter Ii Review Of Related Literature

CHAPTER II REVIEW OF RELATED LITERATURE

The quality of learning attained by a student is related to the quality of teaching done by the teacher. Consequently, better teaching should always bring about better learning and better learning should always show better teaching (Bustos, 1996). To achieve better learning, Anderson (1990), stressed that without necessary tools, teachers are handicapped. And it is sad to know that approximately half of the teachers they interviewed rated their teaching materials as “poor”. Aside from materials Salandanan (2000), pointed out that as a teacher one needs a lot of strategies to better achieve his goal, which is to create an environments open to maximum learning. Furthermore, Lardizabal et al (1996), added that a great deal has been said that teaching is one of the most important professions from a standpoint of human welfare.

Laboratory Method According to Weiss (1985), one of the most generally accepted axiom in chemistry is that despite all of the advances in theory during the past fifty years, chemistry is still an experimental science. Experimental in the sense that one can’t understand chemistry better just knowing its definition, its properties and composition, the laws and principles that govern these changes but by making use of experimentation with apparatus and materials in order to verify physical

9 laws and other facts as well as to study such relationship and discover new facts if possible. Therefore, chemistry needs to have laboratory, for it is often said to be the heart of chemistry course (Beach and Stone, 1980). Lardizabal (1995), defined the term laboratory as a place for doing experiments in natural science where various chemical materials are tested, analyzed, and prepared. He further added that it is a place where learners conform and disprove something or simply test an idea. A laboratory is essential not only as a tool to learn chemistry, but also as a method to learn life skills (Calvo, 1993). It is considered as a method because it is used to designate a teaching procedure (Walton, 1966). To use this method, the instructor should give the necessary directions for work and provide manuals and workbooks to the students. According to Gardner (1989), the laboratory has been expected to help students understand important science concepts, provide concrete experiences in carrying out an investigation and help in developing skills. This is reinforced by Johnstone (1991), when he pointed out that in the laboratory not only concept learned and applied but new skills, equipment and terms are encountered that must be learned and aced upon within the limited time period. The fundamental values of laboratory method are those resulting from practical, first-hand experiences in handling new data, materials and apparatus which cannot be fully realized in any other way. However, Landgrebe (1996), reported that laboratory instruction has deteriorated to the point where it is often uninspired, tedious, and dull. Thus

10 many students find chemistry irrelevant and boring. Johnstone and El- Banna (1986), found that students seem to experience difficulty in integrating their understanding of chemical concepts gained in lecture with the physical phenomena observed in the laboratory. These difficulties could be because a laboratory is complex information- rich environment, perhaps making students simply become overwhelmed in their efforts to process the information effectively.

Lecture Method The lecture is still the most frequently used method

of

instruction.

However, presenting a lecture without pausing for interaction with students can be ineffective regardless of one’s skill as a teacher. The use of pauses during lectures for direct oral questioning creates interaction between teacher

and

students. Unfortunately, when classes are large, the teacher cannot possibly interact with all students on each point. The learning effectiveness of the lecture method then is being questioned because of its lack of interaction. However, it continues as a means of reaching a large group at one time with a condensed, organized body of information. By providing students with lesson objectives

before

the

lecture,

the teacher enables them to listen more

effectively. It helps them to take concise, brief notes concerning the objectives rather than writing feverishly throughout the lecture. Technology

is

the

application

of

science,

especially

to

industrial or commercial objectives. It is also a scientific method and material used to achieve a commercial or industrial objective. It includes new invention,

11 which make mans’ work easier. It also refers to the latest advancements in computers and electronics as well as to the social and political environment and consequences created by such machines (Harrison, 1998). The computer is a powerful and highly motivating learning tool. Used creatively, it can enhance the secondary students’ repertoire of learning skills; increase their access to the curriculum especially those children with a variety of individual needs and from diverse cultural heritage. With increasing pressure on schools to demonstrate the rise in children’s attainment in academic subjects, there can be a tendency for such important goals to be in the sidelines. Opportunities can be created to explore the issues on the way to achieving goals in many subject areas by using computer as a tool. The collaborative use of a highly motivational tool such as the computer provides to facilitate children’s learning growth in these areas (Harrison, 1998). When allied by a computer communication technology can be a window to the world. Websites from many thousands of miles away can be downloaded in a matter of seconds in the computer right inside the classrooms. Moreover, there is a finding that for many children whose lives will increasingly be dominated by computer technology, their only experience with Information Technology is in the classroom. The use of computers to support curricular goals is clearly established in almost all secondary schools (Harrison, 1998). Children have different approach to the use of computer. The interpersonal skills, which children develop are not unique to the work they undertake in the

12 computer but such small group work may be effective in allowing personal development alongside any other learning that takes place (Gonzales, 1998). The PowerPoint is a high-powered software tool used for presenting information in a dynamic slide show format. Text, charts, graphs, sound effects and video are just some of the elements PowerPoint can incorporate into one’s presentations with ease. Whether it's a classroom lesson, a parents' group meeting, a teachers' seminar or an unattended kiosk at the Science Fair PowerPoint shows you how to make a powerful impression on the audience. (http://www.actden.com/pp2003/guide.htm)

“Do-It-Yourself” Instrument When the term laboratory is mentioned in connection with any subject a mental picture is immediately formed of a classroom equipped with long and heavy tables with numerous cases whose shelves are plentiful stock of apparatus and equipment. Although a laboratory is defined as a work shop devoted to experiments in any science with a purpose of observing the laws in operation, formulating its principles, and systematizing them. The question might well be raised then whether it is essential that a student follows directions in performing the experiment or a series of experiments, and whether or not it is possible to do the laboratory work in schools where classes cannot be equipped with real laboratories. Realizing the need of such adaptation after a careful study of the purpose of the laboratory method, leading educators have formulated the following ---“Laboratory methods provide the subject matter an instruction in the

13 form of real, present experiences”. This practice contrasts with the method in which the subject matter is derived through the medium of books or teachers or from the past real experiences of students. (http://links.jstor.org) “Do it yourself”, often referred to by the acronym DIY, is a term used by various communities that focus on people creating things for themselves without the aid of paid professionals. The notion is largely made possible by living in a modern industrial society, and is related in philosophy to the Arts and Crafts movement of the late 19th and early 20th centuries. Many modern DIY subcultures take the traditional Arts and Crafts movement's rebellion against the perceived lack of soul of industrial aesthetics a step further. DIY subculture explicitly critiques modern consumer culture, which emphasizes that the solution to one’s needs is to purchase things, and instead encourage people to take technologies into their own hands to solve needs. Actually, the actual activity of DIY goes back through the ages. Since the beginning of time, people have used their own abilities and available tools and technologies to take care of their own needs. The Department of Education - National Science Teaching Instrumentation Center (DepED-NSTIC) is located at ECOTECH Compund, Sudlon, Lahug, Cebu City. It started as a Philippine-German Cooperation under the Department of Education as Science Teaching Improvement Project (STIP). On July 22, 1993, STIP was institutionalized as NSTIC by virtue of Executive Order No. 112 signed by then His Excellency President Fidel V. Ramos, and was fully operated as such in 1995.

14 The Do-It-Yourself Science Equipment is a program developed by DepEDNSTIC to address the lack of science equipment in government schools. As the name suggests, this equipment is the kind that teachers will have to make themselves. The teachers will be trained and provided with a complete guide on how to construct the equipment. The DIY design utilizes the blue PVC pipe and fittings and aluminum curtain rail for the main parts. Bulldog clips replace the expensive laboratory clamps. Other parts use common household items such as drinking straws, party cups,

empty

soda

cans,

empty

mineral

water

bottles,

etc.

(http://www.nstic.net.ph/). The Center is organized into four operating divisions, namely: Research and Development, Production, Administrative, and Executive divisions. It is managed by an Executive Director, assisted by the Technical Director; while the division chiefs supervise their respective divisions. The Center has a total staff complement of thirty-three personnel, including the two Directors. Supporting the operation of the Center is a complete administrative structure headed by an Administrative Officer. To address the need of fully equipping the schools’ laboratories, NSTIC will develop affordable quality science instructional equipment in the four subject areas of science: Science I-General Science, Science II-Biology, Science III-Chemistry, and Science IV-Physics. There are two types of science instructional equipment, i.e. the standard science equipment and the improvised or Do-It-Yourself (DIY) science equipment. The standard equipment has high precision, used for quantitative experiments, commonly

15 available in the schools, and fabricated in a manufacturing plant. On the other hand, the DIY science equipment is low-cost type and can be manufactured by the teachers themselves. The DIY is an alternative to some of the standard science equipment and can be easily constructed since it is simple, although not comparable to the precision, quality and rigidity of the standard ones; still, it is recommended to be used for qualitative experimentation. The DIY is one of the solutions to the very low availability of science equipment in schools. (http://www.nstic.net.ph/annualreport.htm).

Volume and Temperature Relationship Hot air balloons were extremely popular at that time and scientists were eager to improve the performance of their balloons. Two of the prominent French scientists, Jacques Charles and Joseph-Louis Gay-Lussac, made detailed measurements on how the volume of a gas was affected by the temperature of the gas. Given the interest in hot air balloon at that time, it is easy to understand why these men should be interested in the temperature-volume relationship for a gas. It is expected that the volume of the gas will increase as the temperature increases. If a decrease in temperature results in a decrease in volume, what happens if the temperature is lowered to a point where the volume drops to zero? A negative volume is obviously impossible, so the temperature at which the volume drops to zero must, in some sense, be the lowest temperature that can be achieved. (http://www.chm.davidson.edu/chemistryapplets/gaslaws.html).

16

Atmospheric Pressure Air is a tangible material substance and as a result has mass. Any object with mass is influenced by the universal force known as gravity. Newton's Law of Universal Gravitation states: any two objects separated in space are attracted to each other by a force proportional to the product of their masses and inversely proportional to the square of the distance between them. Thus atmospheric pressure is defined as the force per unit area exerted against a surface by the weight

of

the

air

above

that

surface.

(http://www.2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/prs/def.rxml).

Boiling Point and Pressure The boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid. A liquid in a vacuum environment has a lower boiling point than when the liquid is at atmospheric pressure. A liquid in a high pressure environment has a higher boiling point than when the liquid is at atmospheric pressure. In other words, the boiling point of liquids varies with and depends upon the surrounding environmental pressure. The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, 1 atmosphere. At that temperature, the vapor pressure of the liquid

17 becomes sufficient to overcome atmospheric pressure and lift the liquid to form bubbles inside the bulk of the liquid. The standard boiling point is now (as of 1982) defined by IUPAC as the temperature at which boiling occurs under a pressure of 1 bar. The heat of vaporization is the amount of energy required to convert or vaporize a saturated liquid (i.e., a liquid at its boiling point) into a vapor. Liquids may change to a vapor at temperatures below their boiling points through the process of evaporation. Evaporation is a surface phenomenon in which molecules located near the vapor/liquid surface escape into the vapor phase. On the other hand, boiling is a process in which molecules anywhere in the liquid escape, resulting in the formation of vapor bubbles within the liquid. (http://www.physicalgeography.net/fundamentals/7d.html).

Electrolytes and Non-electrolytes Electrolytes are substances that produce ions in solution. Substances can be categorized as strong electrolytes, weak electrolytes or nonelectrolytes. (http://www2.volstate.edu/chem/111internet/Solutions/electrolytes.html).

Strong Electrolytes Strong electrolytes are substances that only exist as ions in solution. Ionic compounds are typically strong electrolytes. Strong acids, strong bases and salts are strong electrolytes. When solid NaCl is placed in water, it completely

18 dissociates

to

Na+

form

Cl-

and

ions.

(http://www2.volstate.edu/chem/111internet/Solutions/electrolytes.html).

Weak Electrolytes A weak electrolyte only partially dissociates in solution and produces relatively few ions. Polar covalent compounds are typically weak electrolytes. Weak

acids

and

weak

bases

are

weak

electrolytes.

(http://www2.volstate.edu/chem/111internet/Solutions/electrolytes.html).

Nonelectrolytes A nonelectrolyte does not dissociate at all in solution and therefore does not produce any ions. Nonelectrolytes are typically polar covalent substances that do dissolve in water as molecules instead of ions. Sugar (C 12H22O11) is a good example

of

a

nonelectrolyte.

(http://www2.volstate.edu/chem/111internet/Solutions/electrolytes.html).

Tyndall Effect The Tyndall Effect is caused by reflection of light by very small particles in suspension in a transparent medium. It is often seen from the dust in the air when sunlight comes in through a window, or comes down through holes in clouds. It is seen when headlight beams are visible on foggy nights and in most X-File episodes when Moulder and Sculley check out some dark place with flashlights.

19 In liquids the Tyndall effect can be easily seen by using a laser pointer. If you dilute milk to where it is almost clear, or if you have any type of sol, such as colloidal silver, then the beam of the laser can be easily seen as it travels through the liquid. Tyndall effect is seen here using a laser pointer. The glass on the left contains 5 ppm of HVAC colloidal silver and the one on the right is from the tap after the bubbles have settled out. Fairly large particle size was used for this demonstration so it could be caught by the camera in broad daylight. True high quality CS will have a faint, but perceivable Tyndall when viewed in a darkened room (http://silver-lightning.com/tyndall/).