module of lab managemen - dr. khor

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Lecture Module SCE 3112: Management of the Science PISMP Sem 6 Laboratory and Resources 1 Basic knowledge and an adequate understanding of management of science laboratory will provide you with a great experience in preparing effective learning of basic science process scientifically. Good management of a science laboratory will help you to ensure that the laboratory achieves its intended purposes – to enhance and consolidate the theoretical science teaching in classrooms. On the other hand, if a science laboratory is poorly managed, it not only will fail to achieve its intended purposes but will probably affect the students’ interest and enthusiasm in learning science. Systematic science laboratory management includes the following aspects: a. Organization of science committee b. Budgeting c. Ordering and purchasing d. Stock keeping – general maintenance e. Specific maintenance – write off and disposal 1.1 Organization of Science Committee for Science Teachers Who are responsible in the management of science laboratory/room in your school? The flow chart below shows a common organization of science committee in school. The science committee is responsible in managing the teaching and learning activities in science room/laboratory and all science co-curriculum activities. Management of expenses CHAPTER 1 Management of Science Room / Laboratory HEADMASTER SENIOR SCIENCE TEACHER SENIOR SUBJECT TEACHERS LAB ASSISTANTS & ATTENDANTS SCIENCE TEACHERS

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Page 1: Module of Lab Managemen - Dr. Khor

Lecture Module SCE 3112: Management of the Science PISMP Sem 6 Laboratory and Resources

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Basic knowledge and an adequate understanding of management of science laboratory will provide you with a great experience in preparing effective learning of basic science process scientifically. Good management of a science laboratory will help you to ensure that the laboratory achieves its intended purposes – to enhance and consolidate the theoretical science teaching in classrooms. On the other hand, if a science laboratory is poorly managed, it not only will fail to achieve its intended purposes but will probably affect the students’ interest and enthusiasm in learning science. Systematic science laboratory management includes the following aspects:

a. Organization of science committee b. Budgeting c. Ordering and purchasing d. Stock keeping – general maintenance e. Specific maintenance – write off and disposal

1.1 Organization of Science Committee for Science Teachers Who are responsible in the management of science laboratory/room in your school? The flow chart below shows a common organization of science committee in school. The science committee is responsible in managing the teaching and learning activities in science room/laboratory and all science co-curriculum activities. Management of expenses

CHAPTER 1 Management of Science Room / Laboratory

HEADMASTER

SENIOR SCIENCE TEACHER

SENIOR SUBJECT TEACHERS

LAB ASSISTANTS & ATTENDANTS

SCIENCE TEACHERS

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and budgeting is usually handled by the headmaster and assisted by the senior science teachers based on the requirement of the school. Senior science teacher or head of the science committee will handle and prepare all science equipments and materials according to the procedures and requirements. As a science teacher, you have to familiarize yourself with the procedures and activities to be performed so that you know how the laboratory needs to be set up and what materials to have on hand. You’ll also need to be prepared to enforce all safety rules and allow sufficient cleanup time. 1.2 Responsibilities and Duties of the science staff Cooperation and accountability of the committee members will help science teaching and learning to occur smoothly and effectively for student benefits. The table below shows you the responsibilities of each member of the science committee in school.

Committee member

Responsibility

Headmaster/principal

overall supervision of laboratory management to see that the laboratory is properly managed to make decisions on all matters concerned with the

laboratories including budgeting and expenses frequent consultation with the senior science teacher

Senior Science Teacher

People who work in the science laboratories Give advise to the headmaster about any decision made Must be expert on all matters related to the science

laboratory See that all instructions and rules are strictly adhered to by all

staff of the laboratories

Senior subject teacher

Appointed to see to each category of laboratory (not

applicable in primary school) To help the senior science teacher To look after the administration of his science laboratory

Science Teachers

To supply information to the senior science teachers on any

need in the laboratories Immediately responsible to the senior science teacher

Laboratory assistants and attendants

In charge of general cleanliness of the laboratory Supplying and setting up apparatus for any practical lesson Responsible to the senior subject teachers

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1.3 Budgeting Planning of annual budget is important in order to ensure all science equipments and materials needed are available for a proper science teaching and learning. Budgeting for the year is usually done in the year before. In preparing the annual budget, you have to consider the following points:

Check all stock of science equipment and materials Equipment / non consumable materials costs. Running costs to maintain levels of stocks and other expandable materials. List of equipments and materials need to purchase based on their priority Information about number of student enrolment for expected of allocation to be given Prepare price quotation for all equipments and materials to be purchased

For primary school, all science equipments and materials are acquired through

i. Central supply – which is handled by Bahagian Pembangunan dan Bekalan, Kementerian Pendidikan. Please refer to Surat Pekeliling Bahagian Pembangunan dan Bekalan, Kementerian Pendidikan Malaysia, Bil 1/Tahun 1980, dated 27 October 1980, for further detail.

ii. Direct purchase – Please refer to Pekeliling Kewangan 3/95 – KP1573/17/Jld.10/(39 ) and Buku Garis Panduan Perakaunan dan Kewangan

Sekolah, Kementerian Pendidikan, 1994

iii. Other resources – schools are encouraged to add and supplement the equipments, science materials and teaching and learning resources from other sources such as PTA/PIBG.

For more details on the science committee member responsibility you are suggested to make a reference to PPK (1999), Pengurusan Dan Keselamatan Makmal Sains Sekolah, PPK: KL

Plan and estimate the expenses for your school science laboratory. Try to work out how the allocation of funds for science laboratory is distributed to school.

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1.4 Ordering and Purchasing Science Equipments and Materials When the item you want to purchase is identified, you have to follow the standards procedure in acquiring equipment and science materials as required by the Government. The flowchart below shows the procedures to be followed when making ordering and purchasing of science equipment and materials for your school science room.

Yes

No

Yes

No

Estimates of annual allocation and

budgeting

Check whether

equipment is in the Central

Contract

List of material and equipment

Meeting to select the supplier Identify the quantity

required

Recording into the stock book

Receiving

Ordering

Approval from the headmaster/

principal

Direct purchaser

Confirmation of invoice for payment

Prepare a priority list

Prepare a list of material/equipment

based on the chosen suppliers

Obtaining quotation

Describe the procedures you follow in acquiring equipment and science materials for your school science laboratory.

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1.5 Stock Keeping In some schools, there are no proper record for stock keeping of science equipments and materials as required. This situation will invite various problems in verifying the availability of the equipment and materials when needed. Therefore, stock keeping is important in order to check, to identify, to up date and to manage the science laboratory effectively. As a science teacher you should know that all science equipments and materials received or removed have to be recorded as instructed in Pekeliling Perbendaharaan Bil. 2 Tahun 1991- Penggunaan Borang Baru Bagi Pengurusan Harta Modal, Inventori dan Bekalan Pejabat, S(K&B)(2.00)735/3/1-68 Jld.6(SEM)/(3) dated 9 February 1999. You do this by using the respective form indicated in bracket below. Do you know how many stock books should the lab have in your school? Usually there are four Stock Books used for keeping of stock records:

Register of property – to record all non-perishable items worth RM500.00 and more (KEW 312 and 312A). Can you give few examples of these items found in the lab?

Inventory – to record all non-perishable items worth less than RM500.00 (KEW 313). . Name several examples of the items which commonly have in the science classroom/laboratory. Register of office supplies – to record all perishable items (equipments and chemical

materials) which are cheap and not economic to detect their used in detail. (KEW 314). List some examples of the items in your science classroom.

Register of mobile properties and inventories – to record the movement of all the

properties and inventory (KEW 316) Beside these four stock record books, science labs are also required to have two more books which are useful to help you in updating and checking stock. These books are

Book of breakages – to record all broken, damaged and lost equipments or apparatus; Disposal Records of Science Equipment – to keep track that all the disposal

procedures have been followed accordingly. (Please refer to Buku Panduan Penerimaan Peralatan Sains Sekolah Rendah dan Tindakan Kuatkuasaan Bagi Kontrak Kementerian Pendidikan Malaysia, 1994)

(Please refer to appendix for the example of forms used for keeping stocks)

To get more detail information on this section and on how to use all the forms, you can read Chapter 5 of PPK (1999), Pengurusan dan Keselamatan Makmal Sains Sekolah, PPK, K.Lumpur.

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1.6 Writing off and Disposal Sometimes it does happen that you cannot get or cannot use certain equipment or apparatus in the lab while there is a record of its availability in the stock or they are not in a good condition as expected. These equipments may be lost or removed without trace of damaged, rotten, spoilt, broken and old. What are you going to do in these cases? You may consider writing off or disposing it! 1.6.1 Procedure for Writing Off You might suggest writing off if the property which is no longer available in stock due to lost because of theft, cheating or carelessness of the staff. The school head needs to follow the write off procedure as listed in the Arahan Perbendaharaan 314 and 315: The procedures are

Make a police report immediately and get a copy of the report Prepare a lost report using treasury’s form (Form J) and sent this form together with

the police report to : - Ketua Setiausaha,

Kementerian Pendidikan Malaysia (u.p.: Bahagian Kewangan)

- Ketua Setiausaha, Kementerian Kewangan Malaysia (u.p.: Bahagian Pentadbiran)

Send a copy of the report to : - Akauntan Negara - Ketua Audit Negara and Wakil Tempatan Ketua Audit Negara - Pejabat Audit Sekolah - Pegawai Pendidikan Daerah/ Pegawai Pendidikan Bahagian - Jabatan Pendidikan Negeri - Bahagian Sekolah/ Jabatan Pendidikan Teknikal.

Carry out full investigation and prepare a final report using treasury’s form (Form Kew). Arahan Perbendaharaan 317.

Send the report to all the authority stated above. Get the approval to write off from Ketua Setiausaha, Kementerian Pendidikan Malaysia

for property less than RM20,000 per unit or a total value of RM200,000. For property exceeding RM20,000 per unit or a total value of RM200,000 approval must come from Ketua Setiausaha Perbendaharaan Malaysia.

If you notice there are a number of apparatus or science materials that are old, condemned, broken or spoilt. What will you do with these items? Of course you have to carry out a disposal procedure to eliminate the record of such materials from the stock. There are two ways to carry out disposal i.e. through “Lembaga Pemeriksa” or without going through the “Lembaga Pemeriksa”.

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1.6.2 Procedure for disposal Disposal of apparatus or materials valued more than RM10, 000 per unit must go through “Lembaga Pemeriksa” which consists of at least two senior officers who are not directly in the science stock management. Disposal of apparatus or materials valued more than RM100 per unit or a total value of RM5000 is done by the senior science teacher filling in the form (kew 300V) and send to “Bahagian Kewangan, Kementerian Pendidikan Malaysia” through the state education department. For value less than RM100 per unit or total value of RM5000 the form has to be sent to Pengarah Pendidikan Negeri/ Pengarah Bahagian Sekolah/ Pengarah Pendidikan Teknikal. 1.7 Smart School Science Laboratory Smart school was first introduced in Malaysia in 1980. What is the significance to the teaching and learning of science? Do you think school science labs should be upgraded so that it could provide smart learning? So how does a smart science laboratory looks like? It could be characterized by their:

Accessibility and flexibility in design, facilities and functions Technology-based - Integrating of Information Communication Technology such as

using microcomputer-based in which students will be able to visualize various scientific concepts and also promote active learning.

User friendly – in terms of space, situation, environment, availability of materials, and services.

Safety measures – highly guarded with standard safety rules in all aspects.

To get a more detail information on this section , you can read in Chapter 6 of PPK (1999), Pengurusan dan Keselamatan Makmal Sains Sekolah, PPK, K.L.

Build a flow chart to show the write-off process of equipment in the science laboratory.

Based on your school science laboratory, list down any signs of smart characteristics that can be enhanced as smart science laboratory.

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1.8 Smart Science Classroom Designs

A Smart Classroom is an interactive learning environment where computers and other electronic devices are the primary information delivery systems. Teachers serve as facilitators who personalize and individualize the learning opportunities of students. Electronic portfolios hold student products. Computer-assisted instruction provides immediate assessment and feedback. Students can access a wide range of information sources via internet. Internet access is available in every classroom in the school.

Technology is thoroughly integrated with the core curriculum and state frameworks. Students are exposed to a variety of technology applications including multi-media productions, use of data bases, video production, satellite television, instructional software, distance learning, and teacher-authored software. Smart Science Classrooms, could provide our students with extraordinary opportunities for learning.

Let us explore an example in USA.

Black stock's Smart Science Classroom and Technology Lab 2000 are examples of an eighth grade science programs, incorporating computer activity and multi-media instructional techniques in all aspects of their operation. The science classrooms are all unique in design, but they function on a multi-media platform that includes: computer networks, VCRs, laser disk players and CD-ROMs. Technology plays a vital role in the science curriculum. The teacher assumes the role of a facilitator and technology is the tool that delivers the curriculum. The science student can be observed working on a Mineral Unit utilizing a variety of approaches: laser disk - visual examples of mineral terms; software -"Murphy's Minerals" - students are miners searching for valuable minerals; hands-on activity -students identify minerals using scales, streak plates and hardness kits. As students study space, they journey into the solar system via teacher-directed laser disk programs. Working in groups, they search for a lost space probe that has landed on one of the planets. Students may journey with the Apollo 11 astronauts, observing, discussing, describing, and analyzing objects and events they encounter along the way.

Black stock's science program heartily reflects the National Goal of USA to have their students rank first in the world in scientific and technological achievement. The science department embraces scientific literacy, the ability to develop critical thinking and problem-solving skills, to use scientific methods and to make aesthetic judgments. We integrate science topics across all curricular areas, including language arts and mathematics. The Smart Science Classrooms are alive with the sounds of students using word processors to record their observations and to write their laboratory reports. Printers are busy with science newsletters, banners, and signs. Students study the metric system, read and draw graphs and charts, and measure and calibrate distance both on and off their computer systems.

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Adapted from : http://blackstock.huensd.k12.ca.us/html/rm_sci.htm Do you think we could adopt and adapt the above example in our science classroom or science laboratory? Look at the following example of a sitting layout of how a smart science classroom could look like. Which do you think you could use in your own classroom?

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.

Adapted from: Spencer Kagan: Cooperative Learning

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Adapted from : Poh Swee Hiang : Pedagogi 4: Pengurusan Makmal dan Sumber Sains

The above illustration shows an example of how students can access and carry out investigation in a virtual chemistry laboratory.

Can you suggest the advantages and disadvantages of carrying out experiment or science investigation in virtual laboratory?

Well done, take a break now! Time for a cup of coffee

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Appendix 1 Register of Property (KEW 312 & KEW 312A)

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Appendix 2 Register of Inventory (KEW 313)

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Appendix 3

Register of Office Supplies (KEW 314)

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Appendix 4 Register of Mobile Properties and Inventories (KEW 315)

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Appendix 5

Books of breakages

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2.1 Introduction As discussed in the first topic, science laboratory is an important asset in the teaching and learning of science. Science laboratory has long been considered as fundamental facility where student are encouraged to actively involve in teaching and learning process such as experimenting, demonstrating, carrying out science project, studying phenomena and closely interact with physical materials. Therefore, science classroom/laboratory has to be managed properly so that their purpose could be achieved. In this topic, you will learn about the safety in the science laboratory and how to manage and organize the science laboratory in a proper way and some of the basic laboratory techniques. 2.2 Rules and Safety in the Laboratory Some science activities might be dangerous if there is no safety precaution measure taken. But this should not discourage anyone from doing science practical work. For this purpose, you serve as the role model for the behaviour in the laboratory that you expect from your students. Review the following general laboratory safety guideline for teachers. 2.2.1 General Laboratory Rules: You have to follow to some general safety rules stated below before you could tell your students to do so.

Never leave students unattended in the science room/laboratory. Be aware of students with allergies or other medical conditions. Instruct students about the hazards involved with the handling of laboratory equipment

or materials used. All accidents should be reported to the senior science teacher and headmaster and be

recorded in a log book. General cleanliness of the laboratory and preparation room should be adhered to at all

time. Preparation room should not be used for recreation. Always wash your hands with antibacterial soap and warm water upon entering the

laboratory, after live cultures have been handled, after cleanup, and before removing safety goggles.

Then, on the first day of class, introduce or review the safety guidelines that are the student’s responsibility. Here are the general safety guidelines for students.

Food and drink should not be brought in or kept in the science room/laboratory. Students are not allowed to enter the science/laboratory without teacher’s permission. After usage of all science apparatus and materials, it should be returned to its original

place.

CHAPTER 2

Safety Procedures of Science Laboratory

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Safety procedures such as use of lab coat, wearing shoes and eye goggles should be strictly followed.

All science apparatus and materials should not be taken out of the laboratory except with the permission from person in-charge.

Keep your hands away from your face while working in the science room/laboratory. Tie back long hair and loose clothing to keep them away from flames and equipment. Do not inhale vapours or taste, touch or smell any chemicals or substances directly

unless instructed by your teacher.. Spills of chemicals on floor should absorbed with sand and later allowed to evaporate

in the open. Keep work and lab areas clean, limiting the amount of easily ignitable materials Turn off all burners and other equipment before leaving the lab Carefully dispose of waste materials as instructed by your teacher Wash you hands thoroughly with soap and warm water after each activity.

These rules should be displayed in the science laboratory.

2.3 Safe Handling of Scientific Materials and Apparatus Careful in handling of scientific materials and apparatus during science lesson in the labs would reduce the potential of any unintended risks. You notice that there are many scientific materials and apparatus in the labs that need careful attention in handling it. This includes various forms of chemical, sensitive electrical appliances, radioactive materials and biological materials. Do you follow any procedure or rule in handling these kinds of material? If you are not sure, here are some guidelines and rule to be followed when you are dealing with these materials. 2.3.1 Handling of Chemicals Some chemical materials are very toxic, dangerous and highly sensitive to heat. So, do not take a risk when you deal with it. Keep these rules in mind:

Never heat with open flame. Use steam bath or hot water bath. Handle flammable solvents in exhaust hoods or a well-ventilated area. Unwanted solvents must be returned to solvent store or properly disposed-of

without delay. Flasks containing flammable liquids should not be filled with more than one-half

capacity. When making solvent extractions and shaking volatile liquids release the pressure

frequently. Flammable liquids must not be poured down the sink.

What is your action in order to ensure the students’ safety in your school science laboratory?

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Avoid spillages and wash hands immediately with soap and water if contact occurs. Always pour acid into water. Never use the same spatula to remove chemicals from two different containers.

Always be aware when working with any chemical materials. Below are the hazard symbols (Fig. 3) that can be found on the container of chemical materials:

General danger Risk of fire Risk of explosion Toxic hazard Corrosive Risk of ionizing substance radiation

Figure 3: Hazard symbols 2.3.1 Technique of Pouring Chemical Solutions In the labs, most chemical solution or you call bench solution is stored in brown reagent bottle or the transparent one. To avoid any unintended risk when pouring this solution into other container you have to follow the right techniques. The pictures below show you several techniques when working with chemical solution. You may practice it yourself.

Identify other prohibition signs or hazard signs in your science labs or classroom and give an explanation to it.

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2.3.1.1 Pouring chemical solution from reagent bottle

Figure 4

Can you leave the stopper of the reagent bottle on the bench while pouring solution from it?

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2.3.1.2 Transferring chemical solution using a dropper

You can transfer chemical solution from one container to another container using a dropper. Let’s study the technique shown below:

Figure 5

2.3.1.3 Pouring chemical solution using glass rod

Figure 6 shows the steps when pouring any solution from one beaker to another beaker using glass rod.

Why is step 5 in Figure 5 wrong?

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Figure 6

2.3.2 Handling of Radioactive Materials Is there any radioactive material in primary science classroom? If by accident you come across any kind of radioactive material, what should you do? Usually all regulations regarding the handling of radioactive materials have to be followed. All sources should be shielded, handled, and transported in a manner to prevent anyone from being exposed to unnecessary radiation. To avoid any risk you should be aware to the following precaution:

Radioactive materials should not be allowed to touch the skin; Glassware for use with radioactive sources should be kept solely for such use and

stored separately; After work with radioactive materials the hands and any other parts of the body which

has been contaminated must be thoroughly washed with soap and water; All radioactive materials must be disposed of at the end of the practical classes.

2.3.3 Handling of Biological Materials Biological materials include all kinds of microorganisms (such as bacteria, fungus and virus), insects (such as mosquitoes, cockroaches), small animals (pet animals – e.g. cat, guinea pig, mice, frog, birds etc), and plants. Handling biological materials need careful attention because some of them may carry contamination sources (e.g. biological specimens and bandages, towels, and gloves used in cleaning up blood and other bodily fluids).

While transferring chemical solution how can you avoid spillage?

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To minimize the possibility of any kind of risks you have to follow all standard procedures in handling biological materials from the beginning stage.

All hand to mouth operations should be avoided when handling biological materials; Bacteriological and fungal cultures should be soaked in disinfectant before disposal; Insects and small animals should be placed in a safe cage or aquarium; Any injury like bites and scratches by studied animals should be treated with antiseptic

and further treatment should be taken; All animal disposals should be disposed of properly such as burned or buried; Closely monitor the use of syringes with needles by students; When using syringe to inject methanol, a safety visor should be worn in case the

needle blows off; Wounds must be completely covered before work with animals is undertaken; Wild animals must be introduced into the school with discretion as they may carry

parasite and be a risk to infection; Preserved animal skin should not be handled unnecessarily as they may have been

preserved with arsenical compounds and mercuric chloride; Carefully remove specimens from preservative solutions – wearing gloves and using

tongs or forceps (Warning: Formalin solutions are carcinogenic. Any specimen held in a formalin solution should be soaked in a water bath in a fume hood and then thoroughly rinsed in running water for several minutes);

Consider using films, video, and computer simulations in place of dissection activities. Glassware and microscope slides can be sterilized and reused; Any spillage or accidents must be recorded although there is no injury.

2.3.4 Handling of Electrical Apparatus/Equipments Usually pupils in primary school are very curious, active and helpful. They want to do everything as instructed or not instructed by teacher. But when dealing with any electrical equipments or appliances or apparatus in the labs do not allow your pupils to handle them without your attention or instruction. Failing to follow the rules in handling electrical equipment/apparatus or the electrical appliances which are not properly maintained will cause serious accident. You have to review all the electrical equipments/apparatus/appliances and demonstrate to students the techniques for using these equipments and materials properly. Among the rules are:

Make sure that all electrical cords are in good condition, not frayed; Make sure the circuits are not overloaded; Connections should be made correctly when carrying out experiments; All electrical appliances must be switched off before it is moved or adjusted; No water points or rubber connections carrying water are allowed to come into contact

with electrical apparatus;

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Electrical apparatus connected to the mains should not be touched by wet hands; Do not use metal articles such as rulers or metal pencils or writing pens, or wear metal

jewellery when working with electrical equipment; Be cautious when handling electrical equipment that has been in use. The equipment

may be warm or hot from being used; A D.C apparatus must be used in a D.C circuit; Take precautions to prevent spills on electrical equipment or electrical outlets.

Besides handling scientific materials and apparatus correctly, carefully and safely, you are also required to inculcate in your students the culture of maintenance and cleanliness in the laboratory. You may use the following laboratory cleanup checklist in reminding your student after a lab activity.

Promptly clean up your work area while still wearing your protective equipment.

Turn off all hot plates or burners.

Unplug electrical devises.

Place all waste items in the proper disposal containers. NEVER wash anything down

the sink drain unless instructed to do so by your teacher.

Wash glassware with warm water and detergent. Then rinse the glassware several times with water, with a final rinse of distilled water.

Wash the surface of your worktable.

Return laboratory devises to their storage area as directed by your teacher, carrying them properly.

Wash your gloved hands with warm water and soap, being careful not to get water on the inside of your gloves.

Remove the gloves by peeling them off your hands – start at the wrist and keep working toward the fingers. Do NOT let the outside surface of the glove get in contact with the skin. Dispose the gloves as directed by your teacher.

After your have removed your gloves, wash your hands in warm soapy water. Do NOT touch doorknobs, telephone, textbooks, your goggles, or other items until after you have removed your gloves and washed your hands.

Remove your safety goggles after you have washed your hands.

Wash and sterilize your goggles according to your teacher’s instruction.

Adapted from: Glencoe Science, (2002), Laboratory Management and Safety in the Science Classroom, Glencoe

McGraw-Hill: USA

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2.4 Storage of Science Equipment Proper storage of equipments or materials will prolong their lifespan and may avoid any unintended risks. Here are some general storage patterns and procedures that you could consider practicing in the laboratory: Larger equipment and larger chemical containers should be stored on lower shelves only; Substances should be stored at the correct temperature; All storage shelves and cabinets should be securely attached to the walls. (Do NOT place

hazardous materials in unstable containers or in an apparatus that is not properly secured);

Poisons should be kept locked in cabinet, All containers of biological specimens, syringes and scalpel blades should be kept in

locked storage; Store all active chemicals (with a layer of kerosene over them to prevent contact with the

air) in dark container; Acids and corrosives should be stored in a nonmetal or coated metal, vented cabinet; Store flammable reagent in the smallest quantities possible; 2.5 First Aid for Various Injuries and Accidents Many of the tools and chemicals in the science laboratory can cause injury or allergic reaction if used without proper attention and care. Allergic reactions can be in the form of swelling or hives, muscle cramps, disorientation, unconsciousness, and death from shock or suffocation. Even with best efforts at prevention, emergencies still occur. Therefore, along with practicing effective safety measures, you also must be prepared to act according to the given situation. In cases of emergency, seemingly different responses need to take place simultaneously – call an ambulance, getting the school nurse, using safety equipment, administering first aid, and so forth. At very first step, as to response to different kinds of emergencies, you should:

a) Keep calm in all cases and call for medical assistance; b) In case of injury, send a student to get the school nurse, if available or principal / head teacher.

If the victim is not breathing, restore breathing if you have the training to do so.

Stop any bleeding by applying a light pressure, wearing protective gloves. Prevent shock. A clean fire blanket is useful for keeping an accident victim

warm to help prevent shock. c) In case of fire, begin evacuation and sound the alarm immediately.

d) In case of chemical spill, place affected student in the safety shower or use eyewash station if the spill affects the eyes.

Do you think the scientific equipment in your school science laboratory are properly stored?

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2.6 Giving First Aid What is first aid? First aid is the first assistance provided to a person suffering an accident or a sudden illness. Persons giving first aid should seek NOT to treat the victim but to protect him or her until professional medical assistance arrives. Every teacher bears the responsibility for knowing how to help a student in the case of an accident or illness. In the science labs, student should be aware of the location of the first aid kit, but a teacher should be the one administering first aid. First aid kits should be kept in an accessible place in the classroom or labs. The location should be marked clearly. The table below provides general procedures for injuries most commonly related to school laboratory work. Most injuries are minor cuts and burns to the hand. Many injuries occur when students are cleaning glassware. In addition to the possibility of injury from broken glass, there is the threat of injury from the cleaning solution or chemical substance used with the glassware. Warning: Gloves should be worn by anyone administering first aid.

Type of injuries or accidents First aid procedures

Burn

Heat burns Quickly immerse burn area in very cold water Never prick blisters Cover area with sterile gauze to prevent infection Sent to hospital Chemical burns Contaminated articles and clothing and the source of

contamination should be removed Flush the contaminated area with plenty of water for at

least 15 minutes Cover burns with a sterile dressing (NOT fluff cotton) Seek medical attention

Cuts, wounds and fractures

Remove dirt or glass and wash under running water, wash the injured area thoroughly;

Apply a clean, dry sterile gauze Go to hospital for stitches or anti-tetanus injection if

necessary If bleeding is copious, it must be stopped before aid can

be given Eye injuries

Wash the eye with plenty of continuous stream of water Remember to guide the student as he or she will have

difficulty seeing Send the student to hospital

Refer to Surat Pekeliling KP(BS) 8600/7/A/(81) – “Tindakan serta merta Keselamatan Di dalam Makmal Sains” dated 21 February 1980.

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Type of injuries or accidents First aid procedures

Electrical shock

Switch off the current supply To push victim from current source, the teacher should

stand on insulated material The victim should be down with head lower then the

body, kept warm and still Keep the victim’s airway open. If he vomits, turn his head

on one side so that the neck is arched Start artificial respiration immediately

Fainting, shock and concussions

Lie victim down in the open, keep crowds away Loosen all clothing and place his head between his knees

until it flushes red Smelling salts should be used When he becomes conscious, he may be given some

cold water Call for emergency medical aid immediately

Insect bite and stings

Identify the source of bite or sting If venomous, seek medical help immediately Keep victims calm and quiet. Keep injury area lower than

the heart Poisoning

If in mouth, spit it out immediately and wash with plenty of water and then seek medical help.

If swallowed, give 2-4 glasses of water or milk immediately and induced vomiting. Call doctor immediately.

Do not induce vomiting if poisoning is due to strong acids or alkali or hydrocarbon or when victim is having convulsions. Call doctor immediately.

If inhaled, remove the patient to fresh air immediately. Give oxygen if available using a respirator.

Treat the victim for shock until medical assistance arrives.

2.7 Prevention of Injuries and Accidents Injuries and accidents to your students can be avoided if you are aware to all the safety precaution measures suggested in handling or carrying out science activities in the laboratory or science room. Besides that other physical facilities in the labs should be made available or in good condition. As science teacher you have to be aware of such facilities.

Use proper protective equipment. Floor must not be slippery. No protruding fittings from wall into the walking space. Proper place for storage of pupils’ belongings. Windows can be easily accessible. All mains for gas, water and electricity controls are easily accessible to teachers. Clearly labeled waste container should be available for broken glass, biological

materials and chemicals.

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2.8 Content of First Aid Box One of the most basic equipment that should be in the science classroom or laboratory is a first aid kit. First aid supplies should be kept readily at hand. Immediate aid then can be given while waiting for the school nurse or medical assistance. What are the contents of the first aid kit? At a minimum, supplies should include the following:

Assorted size bandages Disposable gloves (latex or plastic) Sterile gauze for covering large wounds Disposable towels Adhesive bandages for covering small wounds An eye wash bottle An antiseptic (iodine solution – is not recommended, it can cause tissue damage) disinfectant One pair of blunt ended scissors Medical tape Small forceps Bleach (at time needed, prepare a solution of 1 part bleach to 10 parts water) Plastic bags for holding contaminated waste

2.9 Types of Fire and Uses of Suitable Fire Extinguishers

What will you do if the fire happened in the classroom during your science teaching and learning?

Get more information from the library regarding the location and purpose of using goggles and having an eyewash station in the school science laboratory. Refer to Surat Pekeliling KP(BS) 8600/12/A(7) –‘ Keselamatan Dalam Makmal Sekolah’ dated 8 June 1973.

Refer to the Red Crescent Society on how to give first aid to a student who fainted in the school science laboratory.

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Fires can be very dangerous and you should always be certain that you will not endanger yourself or others when attempting to put out a fire. For this reason, when a fire is discovered:

Assist any person in immediate danger to safety, if it can be accomplished without risk to yourself.

Activate the building fire alarm system or notify the fire department by dialing 994 (or designating someone else to notify them for you). When you activate the building fire alarm system, it will automatically notify the fire department and get help on the way. It will also sound the building alarms to notify other occupants, and it will shut down the air handling units to prevent the spread of smoke throughout the building.

Only after having done these two things, if the fire is small, you may attempt to use an extinguisher to put it out.

However, before deciding to fight the fire, keep these rules in mind:

Know what is burning. If you don't know what is burning, you don't know what type of extinguisher to use. Even if you have an ABC extinguisher, there may be something in the fire that is going to explode or produce highly toxic smoke. Chances are, you will know what's burning, or at least have a pretty good idea, but if you don't, let the fire department handle it.

The fire is spreading rapidly beyond the spot where it started. The time to use an extinguisher is in the incipient, or beginning, stages of a fire. If the fire is already spreading quickly, it is best to simply evacuate the building, closing doors and windows behind you as you leave.

2.10 The Fire Triangle

In order to understand how fire extinguishers work, you first need to know a little bit about fire.

Four things must be present at the same time in order to produce fire:

Enough oxygen to sustain combustion, Enough heat to raise the material to its ignition temperature, Some sort of fuel or combustible material, and The chemical, exothermic reaction that is fire.

Figure 7: Fire triangle

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Oxygen, heat, and fuel are frequently referred to as the "fire triangle." Add in the fourth element, the chemical reaction, and you actually have a fire "tetrahedron." The important thing to remember is: take any of these four things away, and you will not have a fire or the fire will be extinguished.

Essentially, fire extinguishers put out fire by taking away one or more elements of the fire triangle/tetrahedron.

Fire safety, at its most basic, is based upon the principle of keeping fuel sources and ignition sources separate.

Besides all the precaution and preventive measures to avoid any fire incident, you should also have the knowledge and the skills of using proper type of fire extinguishers and other anti-fire equipments. Using proper equipment is extremely important in fighting fires. 2.11 Type of extinguishers Have you noticed these types of fire e extinguishers in your schools?

Figure 8: Water (APW) Extinguishers

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Figure 9: Carbon Dioxide Extinguishers

Figure 10: Dry Chemical Extinguishers

There are four classes of fire and they each involve a different method of extinction. Fire extinguishers are labeled for the class of fire they are to be used on. The table below summarizes the fire classes and their respective type of extinguishers

You could obtain detail information about the three types of fire extinguishers from any brochures from the Fire Department, books on science

laboratory or relevant web-sites.

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Class Of Fire

Types of Fire

Suitable Extinguishers

Notes

A

Ordinary combustible materials ( e.g. paper, wood, cloth )

Water or sand. (Soda acid or carbon dioxide) may be used if water is not available. Dry chemical class ABC fire extinguisher

Never use water in the presence of electrical points or equipments. Soda acid causes corrosion.

B

Flammable solvent, oil, liquid. ( acetone, alcohol, ethers, grease)

Carbon dioxide, foam, powder extinguisher or fire blanket. Class B or dry chemical, Class ABC fire extinguisher

Never use water.

C

Electrical equipment or static charges

Carbon dioxide or dry powder. Class C or dry chemical, Class ABC fire extinguisher

Switch off power before tackling fire.

D

Metal fire ( e.g. sodium, potassium, magnesium, metal hydrides )

Special purpose dry powder and sand. Class D fire extinguisher

Never use water or carbon dioxide.

2.12 How to use a fire extinguisher?

It's easy to remember how to use a fire extinguisher if you can remember the acronym PASS, which stands for Pull, Aim, Squeeze, and Sweep.

Pull the pin at the top of the extinguisher that keeps the handle from being accidentally pressed. Aim the nozzle toward the base of the fire. Stand approximately 8 feet away from the fire and squeeze the handle to discharge the extinguisher. If you release the handle, the discharge will stop. Sweep the nozzle back and forth at the base of the fire. After the fire appears to be out, watch it carefully since it may re-ignite!

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P.A.S.S.

P ULL

A IM

S QUEEZE

S WEEP

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CHAPTER 3

Basic Laboratory Techniques

Laboratory is an ideal place where you may acquire knowledge and skills on scientific processes besides acquiring manipulative skills. Manipulative skills in the laboratory start with knowledge in handling apparatus and science materials during science practical work. As a science teacher in primary school, definitely you are expected to have the skills and competent with some basic techniques in handling laboratory materials. Without competency in these basic laboratory techniques skills, you will invite unexpected results or put your student in danger. Some of the basic laboratory techniques are the basic measuring skills, techniques in handling chemical and biological materials and specimen, and some basic technical skills in electrical and glass work. For this purpose, in this section you will learn some basic laboratory techniques such as glass work, preparing of chemical solution, and preservation of biological specimen which are commonly practiced in science classroom or laboratory. 3.1 Glass Work Basic skills related to glass materials are making a cut and heating the glass or melting it. In the laboratory, we usually cut a glass for the purpose of producing a glass rod or heating glass tubing to make a dropper or to bend a glass tube into required shape. What instrument do you need when you want to do some glass work? Usually, we need a glass cutter, a file, meter ruler, sand paper, and Bunsen Burner. File and sand paper to be used to polish the surface or glass edge that has been cut. Bunsen burner is for heating and melting the glass. Can you name the types of glass that are commonly available in your school laboratory? There are two types of glass commonly available in the laboratory. One is soda lime glass or also known as commercial glass. Soda lime glass is made up of a mixture of sodium carbonate (soda ash), calcium carbonate, 5 - 11%(lime) or calcium oxide, and silicon dioxide (silica, 70-74%) This glass is usually used in producing glass tubing. It is soft and can be shaped when heating at 3000C – 4000C with Bunsen burner. Soda lime glass is normally colorless. The other type of glass is borosilicate glass. Borosilicate glass is made mainly of silica (70-80%) and boric oxide (7- 13%) with small amounts of alkalis (sodium and potassium oxides) and aluminum oxide. This type of glass is always used to produce heat-resisting ware, better known under the trade name Pyrex.

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3.2 Glass Cutting

The technique for cutting glass is very simple. You need minimal practice to develop a feel for scoring and breaking out. However, it will help you to observe certain basic and easily understood requirements.

The primary objective in glass cutting should not be merely to sever the sheet but to score and breakout so that the resulting cut edges has good quality surfaces, free of nicks and chips. A nicked or chipped edge is a weak edge and can contribute to glass failure.

What is the right technique in cutting glass? There are two main steps to be followed.

a) Drawing the score line using an appropriate glass cutter. The procedures are summarized below:

The requirements for good scoring are:

A good cutter.

A firm, flat, clean support for the glass. Clean glass. Cutting oil (If necessary – the lubricate the score line)

Not tilting the wheel to left or right. Uniform application of force and speed, maximum non-crushing force. Always do the hardest cut first (inside curves). A score clean of glass chips and barely visible when looking at the surface of the glass.

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b) Breaking out The quickest and easiest method of breaking out the score is to bend the glass, pushing up from the side of the glass opposite the score line while giving some lateral pull. Position your hands by curling your fingers toward yourself on the bottom side of the glass (the backs of your fingers should be touching) and pointing your thumbs away from yourself on the top surface of the glass. The fleshy part of your thumbs should be touching each other (Figure 11). Or you can use other method of breaking out the glass by aligning a straight score on large sheets just inside the table edge, lift and firmly snap the glass down.

Figure 11

After separating the glass it's a good idea to wipe off the bottom edge of the glass piece being saved in order to remove the sharp edge generally left on the bottom side of the glass. Polish the glass edge with glass grinder or a file.

3.2.1 Cutting glass rod and tubes You may be wanted to cut a glass rod or a glass tubing into required length for labs purposes such as to make a stirrer or a dropper. To make a good cut and to avoid an injury you have to follow the right techniques as follow:

a. Make a deep scratch on the glass at the position of the cut using sharp edge of a triangular file or using roller glass cutter. Do this by placing the glass on the table

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top and pressing the file firmly with your thumb while slightly rotating the file (Fig. 12 and 13)

b. After the scratch has been made, grasp the tubing with both hands by placing your

thumbs on the side of the tubing opposite the scratch (Fig. 14)

Figure 12 Figure 13

Figure 14 3.3 Bending glass tubes and making of T-joints The skill in bending glass tubing and making it into other shape is useful to you as an effort to improvise some apparatus in the labs. The most basic bend is the right angle bend. The key to making a good bend is to heat sufficient glass to make the bend, and also to prevent kinking of the glass. For a right-angle bend, mark the glass tube so that the portion of the surface placed into fire equals two full diameters of the tube. For examples if 10mm tubing is to be bent, small marks should be made on the 10mm in either direction from the center of the bend, creating a heating zone of 20 mm. To make a bend of glass tubing, Figure 15 shows the steps to be followed.

a. Place a flame spreader (wing top) on the burner. Rotate the piece of glass in the hot part of the flame (top of the inner cone) so that the flame spreads out along the glass, until the glass becomes yellow and soft.

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b. Remove the glass from the flame and immediately bend into the desired angle as shown. Do not attempt to rebend it as it cools. If it becomes hard it will shatter.

c. Place the bend on a ceramic plate or wire gauze to cool.

Figure 15 Figure 16 Figure 16 shows the steps in making T-joint tubing. In making T-joints, the two glass tubes should whenever possible be no longer than 15 cm to facilitate manipulation. The steps are described below

a. Cork one end of the glass tube and heat the center in the flame. Replace the flame to a very fine point and direct it onto the place at which the joint is to be made. Blow with the help of a rubber tubing a small bubble about the size of the tube to be joint.

b. Heat the center of the bubble in the tip of the flame and blow out. Using a file carefully scrape away broken pieces of glass leaving a hole where the joint is to be made.

c. Cork both ends of the glass tube and hold it in the left hand so that the edge of the flame plays on the edges of the hole. Heat the other tube simultaneously in the other edge of the flame.

d. When the glass is hot enough press the two together, so that the side tube makes contact all round its circumference and is squarely placed. Reduce the flame to a fire point. Heat one side of the joint until the glass is molten over

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about one-quarter of the way round the joint. Blow until the glass is completely united.

e. Proceed all round the joint. Heat the whole joint, straighten and square up the tubes. Anneal the joint.

3.4 Fire Polishing glass tubing/rods

After making a cut, usually you will get the edge of the glass tubing or rod is not smooth and dangerous to hold. To make it smooth and round, you can do fire polishing as the steps follow. (Figure 17)

a. Hold the end of the tube to be fire polished in the hot part of a Bunsen burner flame (tip of the inner cone). Rotate the glass until it becomes yellow, begins to melt, and is rounded. You have to be careful, because excessive heating will cause the tube to become closed.

b. Remove from the flame and cool on a ceramic plate or wire gauze.

Figure 17

3.5 Making of droppers Dropper is a simple apparatus that is commonly used in science classroom for transferring reagent from the bottle to other container or dropping of solution. This apparatus can be made

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by science teacher easily in the laboratory. Figure 18 shows you the techniques in making of a dropper.

a. Hold both ends of the glass tubing. Heat the center of the glass while rotating it. Keep rotating it until the glass becomes yellow and soft.

b. Pull both ends of the glass while heating it until it forms a capillary tube. Then pull the capillary tube to form two split tubes, where both are with a capillary ends as shown below.

c. Cut the capillary ends to allow the capillary tube formed. Fire polish the other end of the glass tube to be fitted with rubber teat.

Figure 18 All the basic techniques described are the beginnings of glass-working. They are not easy to do and require much practice but glass working can be a very worthwhile skill for science teacher and laboratory assistants to develop.

1. Using the materials available in your school laboratory and based on the glass work techniques learned, design and make a U-tube and S-tube. 2. Using glass cutting techniques, design a beaker or mug from an unused glass bottle found around your school.

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3.6 Preparation of Chemical Solutions When a substance, called a solute, is dissolved in another substance, called the solvent, a solution is formed. A solution is a uniform distribution of solute in solvent. For example, vinegar is a solution of acetic acid, the solute, in water, the solvent. The amount of solute in a solvent is important and can be expressed in several different ways. Some common units of concentration will be discussed. The purpose of this section is mostly for practical experience in solution preparation in the laboratory, it is probably one of the most fundamental tasks in many laboratory experiments. To have someone else prepare your solutions for you is a luxury (as you will soon find out), don't take it for granted. In preparing chemical solutions you will be ‘dealt’ two tasks. The first task requires you to prepare a stock solution (or standard solution) of a specific volume and molarity by dissolving an appropriate amount of the specified solute. The volume of solution will be “measured” by using a volumetric(vol) flask. A vol. flask is made to contain a specific volume of liquid when the flask has been filled to the meniscus mark. This mark is a line indicating when the flask contains the volume specified on the flask. To prepare a solution using a vol. flask, you first place your solute sample into a clean flask of the desired volume. Enough solvent is then added to reach half way up the main (round) body of the flask. The flask is then capped and gently shaken to dissolve the solute. Be sure that the top is on tight before and during shaking. Then add additional solvent to just below the meniscus mark. The flask is again carefully shaken. Dislodge any air bubbles attached to the walls of the flask by tapping the side of the flask. Using a dropper or a pipette, the liquid level is then filled up to the line such that the bottom of the meniscus is at the line. The flask is again shaken. The volume of solution should be the same as the size marked on the side of the flask. The second task requires that you use the stock solution prepared in the first task to prepare a second solution that is more dilute than the solution in the first task. To make a dilution, the desired volume of “concentrated” solution is transferred using a pipette to a second vol. flask. After the concentrated solution has been transferred to a second vol. flask, the procedure for filling to the line is the same as in the first task.

3.6.1 Solutions with specified concentrations Another way of expressing concentration, the way that we will use most in this course, is called molarity.. Now we will see how solutions of a specific molarity can be made.

Do you realize that standard solution is also known as reagent?

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3.6.1.1 Molar solutions

Molarity is a useful way of describing the concentrations of solutes in solution, as well as a source of useful conversion factors for converting between volume (an easily measurable property of solutions) and moles of solute.

Molarity is the number of moles of solute dissolved in one liter of solution. The units, therefore are moles per liter, specifically it's moles of solute per liter of solution.

The abbreviation for molarity is ``M'' so that a 0.1 molar solution is represented as 0.1 M solution.

A 0.1 M solution of HCl has 0.1 mol of HCl dissolved per liter of solution.

So when you see M or M it stands for molarity, and it means moles per liter (not just moles). You must be very careful to distinguish between moles and molarity. "Moles" measures the amount or quantity of material you have; "molarity" measures the concentration of that material. So when you're given a problem or some information that says the concentration of the solution is 0.1 M that means that it has 0.1 mole for every liter of solution; it does not mean that it is 0.1 moles. Please be sure to make that distinction! To prepare a 1 M solution, slowly add 1 g formula weight (FW) or relative molecular mass (RMM )of compound to 500-mL distilled or deionized water in a 1000-mL volumetric flask half filled with distilled or deionized water. Allow the compound to dissolve completely, swirling the flask gently if necessary. Once the solute is completely dissolved and the solution is at room temperature, dilute to the mark with water. Invert the flask several times to mix. Exercise 1: If you are given 40g sodium hydroxide (FW = 40), describe the steps taken to prepare a 1 M solution of sodium hydroxide. In order to make a calculation for preparation of solution required, you will find the following equations very useful:

Mn m

solute

soln

solute

solnV VM

C V C V1 1 2 2 where

M = molarity concentration of solute V1 = volume of stock M = molar mass of solute C1 = concentration of stock

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nsolute = moles of solute V2 = volume of dilute msolute = mass of solute in grams C2 = concentration of dilute Vsoln = volume of solution in liters Exercise 2: Determine how many grams of reagent used to make 0.15 M solution. Given Chemical FW = 194.3 g/mole. (ans. 29.145g) Exercise 3:

A chemical has a FW of 180 g/mole and you need 25 ml (0.025 L) of 0.15M (M = moles/L) solution. How many grams of the chemical must be dissolved in 25 ml water to make this solution? (Ans. 0.675g).

3.6.1.2 Percentage Solutions

Many reagents are mixed as percent concentrations i.e. part per hundred. When working with a dry chemical it is mixed as dry mass (g) per volume where number of g/100 ml = percent concentration. A 10% solution is equal to 10 g dissolved in 100 ml of solvent.

Therefore, mass percent means the number of grams of solute per 100 g of solution. For example, 10 g sodium chloride in 90 g water is a 10% by mass solution.

mass percent = mass of solute/mass of solution = 10 g / (10 g + 90 g) x 100%

= 10% This would be labeled as a weight/ volume [w/v] percentage solution.

Example 1:

If you want to make 3 % NaCl you would dissolve 3.0 g NaCl in 100 ml water (or the equivalent for whatever volume you needed).

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When using liquid reagents the percent concentration is based upon volume per volume, i.e., number of ml/100 ml.

Therefore, volume percent means the number of milliliters of solute per 100 mL of olution. The volume percent of a solution cannot be calculated directly from the volumes of its components because the final volume may not equal the sum of the components’ volumes.

To prepare volume percent solutions, first determine the final volume and concentration of the desired solution and then determine the amount of solute. Dilute the solute in sufficient solvent to produce the final volume of desired solution. For example, to prepare 100 mL of a 10% by volume solution of acetic acid, dilute 10 mL acetic acid with distilled or deionized water to make 100 mL of solution.

By understanding how to prepare molar and percent solutions you will also be able to convert from molar solution to percent solution or vice versa.

To convert from % solution to molarity, multiply the percent solution value by 10 to get grams/L, then divide by the formula weight.

Molarity = (% solution) * 10 xxxxxxxxxx FW

To convert from molarity to percent solution, multiply the molarity by the FW and divide by 10:

% solution = molarity * FW xxxxxxxxx x10

Example 2:

If you want to make 70% ethanol you would mix 70 ml of 100% ethanol with 30 ml water (or the equivalent for whatever volume you needed).

Example 3: Convert a 6.5 % solution of a chemical with FW = 325.6 to molarity [(6.5 g/100 ml) * 10] / 325.6 g/L = 0.1996 M

Example 4: Convert a 0.0045 M solution of a chemical having FW 178.7 to percent solution: [0.0045 moles/L * 178.7 g/mole] / 10 = 0.08 % solution

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Could you understand them? Probably it’s a good idea if you could find a laboratory assistant or a senior science teacher to demonstrate the steps in preparing the solution. The following simplified steps could also help to prepare the solution.

Complete the following information, showing ALL pertinent calculations:

Preparation of the Stock solution:

a) Name of solute to be dissolved

b) Formula of solute.

c) Molar mass of solute.

d) Desired molarity of stock solution

e) Desired volume of stock solution f) Grams of solid desired

g) Grams of solid actually measured

h) Calculated actual stock concentration

i) Briefly describe the preparation procedure

1. A solution is prepared by placing 10.0 grams of aluminum nitrate into a volumetric flask. The aluminum nitrate is then dissolved in water such that the final volume is 200.00 mL. What is the concentration of aluminum nitrate expressed as a molarity? 2. Describe the step-by-step procedure used to actually prepare the solution in pre-lab question 1. 3. From the solution prepared in pre-lab question 1, what volume (in mL) of the solution from question #1 would need to be diluted to form a 100.00 mL solution having a concentration of 0.064 M aluminum nitrate? 4. Given that you have been assigned to prepare a 0.100 M magnesium chloride solution with a volume of 500 mL (known volume of 500.0 mL). What glassware would you use and what mass of magnesium chloride would be necessary?

Do these exercises to help you better understand this section!

To get more details you can visit this website: http://dl.clackamas.cc.or.us/ch105-05/volume.htm http://www.lsmsa.edu/MKhandoker/Chemistry/laboratories/Preparation%20of%20Molar%20Solutions.htm

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5. A calcium acetate solution was prepared and determined to have a concentration of 0.250 M calcium acetate. The solution was made using 59.3 grams of calcium acetate, what volume (in mL) of solution must have been made?

Common reagent solutions in school science laboratory are prepared by dissolving solute in distilled water or prepare it from stock solution.

The following steps describe the procedure for making a solution of a specific molarity from a pure, solid substance.

First, weigh out the correct mass of solute in grams use a measuring cylinder if liquid. Dissolve the solute in distilled water (or deionized water) in a beaker, heating and

stirring as necessary. Keeping the volume less than the desired total volume of solution

Dilute the solution and make up to the desired total volume of solution. Shake thoroughly to ensure that the concentration is the same through out the

solution. Some examples of reagents used in school:

Reagents How to prepare Acetic Acid, 1 N Dilute 57.5 mL of glacial acetic acid with water to 1 L.

Benedict’s Solution Dissolve 173 g of sodium citrate dihydrate and 100 g of

anhydrous sodium carbonate, Na2CO3, in 800 mL of water. Heat to aid dissolution, filter if necessary, and dilute with water to 850 mL. Dissolve 17.3 g of copper sulfate pentahydrate, CuSO4

. 5H2O, in 100 mL of water. Add this solution, with constant stirring, to the alkaline citrate solution, and dilute with water to 1L.

Hydrochloric Acid, 20% HCl Dilute 470 mL of hydrochloric acid with water to 1 L

Hydrochloric Acid, 10% HCl Dilute 235 mL of hydrochloric acid with water to 1 L

Hydrochloric Acid, 7 M Dilute hydrochloric acid (1 + 1) with water.

Potassium Chromate.

Dissolve 10 g of potassium chromate, K2CrO4, in water and dilute with water to 100 mL.

Silver Nitrate.

Dissolve 17 g of silver nitrate, AgNO3, in 1 L of water. Store in an amber bottle.

Starch Indicator Mix 1 g of soluble starch with 10 mg of red mercuric iodide and enough cold water to make a thin paste, add 200 mL of boiling water, and boil for 1 min while stirring. Cool before use

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The discussion above suggests that there are two general ways to make solutions of a given molarity:

The solutions can be made starting with pure solute and water The solutions can be made from more concentrated solutions

3.6.2 Diluting concentrated solution

Understanding how to make dilutions is a an essential skill for a science teacher. This skill is used, for example, in making solutions, diluting bacteria, diluting antibodies etc.

Laboratory solutions are often made in high concentrations in order to store smaller volumes. Quite often, however, solutions are prepared by diluting a more concentrated solution. For example, if you needed a one molar solution you could start with a six molar solution and dilute it. Consequently, you also need to be familiar with the calculations that are associated with dilutions.

It is important to understand:

how to do the calculations to set up the dilution how to do the dilution optimally how to calculate the final dilution.

When preparing a dilution, decide the volume and molar concentration of the resulting solution that you require. Use the following equation to determine how much of the concentrated reagent is needed to prepare the diluted solution,

M reagent x V reagent = M dilution x V dilution

where M is molarity and V is volume.

Slowly add the calculated volume of concentrated reagent to a proper-sized volumetric flask half filled with distilled or deionized water and swirl the flask to mix. Once the solution is at room temperature, dilute to the mark with water and invert the flask several times to mix.

Example 1:

What volume of 10 M acetic acid is required to prepare 1.0 L of 0.50 M acetic acid?

10 M x V reagent = 0.50 M x 1.0 L

V reagent = 0.050 L = 50 mL

A volume of 50 mL of 10 M acetic acid is required to prepare 1.0 L of 0.50 M acetic acid.

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a) Desired molarity of dilute solution

b) Desired volume of dilute solution

c) Volume of stock solution required

d) Calculated actual concentration of dilute solution

e) Concentration of solute as determined by conductivity probe.

f) If the concentration determined using the conductivity probe is different than your calculated actual concentration, then determine the percent error of your value.

g) Briefly describe the preparation procedure:

1. How much 2.0 M NaCl solution would you need to make 250 mL of 0.15 M NaCl solutions? (ans. 18.9mL)

2. What would be the concentration of a solution made by diluting 45.0 mL of 4.2 M

KOH to 250 mL? (ans. 0.76M)

3. What would be the concentration of a solution made by adding 250 mL of water to 45.0 mL of 4.2 M KOH? (ans. 0.64M)

4. How much 0.20 M glucose solution can be made from 50 mL of 0.50 M glucose

solution? (125mL)

Do these exercises to help you better understand this section!

Do you think by completing the following information will help you better to

prepare a dilute solution? If so use them, if not forget about this!

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3.6.2.1 Diluting Concentrated Acids You notice that there are a number of concentrated acids used in science labs. For example, the hydrochloric acid solutions a science teacher is likely to use in reactions have concentrations of 1 M HCl or 6 M HCl, but solutions of this concentration would take up an inconvenient amount of storage space in a science labs stockroom. Therefore, a concentrated hydrochloric acid solution, usually about 12 M HCl, is purchased and stored, and diluted with water whenever a more dilute solution is needed.

The concentrations of typical concentrated acid solutions and for the base ammonia are listed in the table below.

Typical Concentrations of Concentrated Acids and Ammonia Substance Molarity Mass perccentage

Hydrochloric acid, HCl(aq) 12.1 M 38.7% Sulfuric Acid, H2SO4 17.8 M to 18.4 M 95%-98% Nitric Acid, HNO3 15.8 M 69.71% Acetic acid, HC2H3O2 17.4 M 99.7% Ammonia, NH3(aq) 14.8 M 28%

The following is the general procedure for diluting a relatively concentrated solution to form one that is more dilute. (There is a slightly different procedure for diluting acids that are almost pure, like concentrated sulfuric acid, which is 95-98% H2SO4. We will restrict our examples to the dilution of solutions that already contain a significant amount of water.)

Add the correct volume of the more concentrated solution to a volume-measuring instrument, like a volumetric flask.

Add water until the volume reaches the desired total.

It is important only to pour acid into water, not the other way around, especially with concentrated acids. Acids may quickly absorb water, creating a lot of heat in the process. When acid is poured into water, the heat can quickly become evenly distributed in the water. If water is poured into acid, the water may quickly boil, spraying acid everywhere. 3.6.3 Volume to Volume Dilutions

This type of dilution describes the ratio of the solute to the final volume of the dilute solution.

For example, to make a 1:10 dilution of a 1M NaCl solution, you would mix one "part" of the 1M solution with 9 "parts" of solvent (probably water), for a total of ten "parts."

Dilution of concentrated acid should always be done in a fume cupboard

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1:10 dilution means 1 part + 9 parts of water

(or other diluent).

For example: if you needed 10 ml of the 1:10 dilution, then you would mix 1 ml of the 1M NaCl with 9 ml of water

or: if you needed 100 ml of the 1:10 dilution then you would mix 10 ml of the 1M NaCl with 90 ml of water. The final concentration of NaCl in both cases is 0.1M.

3.7 Preservation of Biological Specimens

Learning and teaching of Biology is complete only when the student is able to see active living and preserved variety of organisms. Learning Biology also becomes easier by observing living organisms closely rather than merely reading about them. Living animals are kept in animal house, frogs in a specially constructed froggery, and fish in aquarium. Plants are grown in the botanical garden or specially maintained in a green house.

If you cannot get hold of a living organism then the next step is to use a preserved organism. Preserved animals and plants, duly classified are kept in museums. If a preserved organism is not available then use charts and models. Usually they are also displayed there.

There are two way to preserve an animal or a plant (1) wet preservation and (2) dry preservation.

To get more details you can visit this website: http://abacus.bates.edu/~ganderso/biology/resources/dilutions.html http://www.carolina.com/chemistry/resources/solution_preparation.asp

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3.7.1 Preservation of Plant Specimen

a) Dry preservation or Herbarium

What do you understand from the word ‘herbarium’? You are right if you say it has something to do with plants.A herbarium is defined as a collection of plants that have been dried, pressed and preserved on sheets. The dried plants are classified and arranged for future reference especially taxonomic studies.

A herbarium (herbaria, plural) is a repository, a facility designed to ensure long-term preservation of scientific plant samples, generally referred to as specimens. The most meaningful analogy is to a library; herbaria are plant libraries, with the specimens corresponding to the pages in books. Most herbaria are under the aegis of an academic institution, museum or botanical garden.

Most herbaria are housed in a room full of specially designed steel cases (herbarium cabinets). Typically, the interior of the cabinets is divided into two vertical sections and each section is subdivided into 13 compartments. Herbarium cabinets are lined up side-by-side in rows, and they take up considerable space because there must be sufficient room for the doors to open between rows. In recent years, some herbaria, particularly larger ones, have installed mobile shelving (compactors), placing rows of cabinets or compartmentalized shelving on tracks. The rows are moved via manual or electrical systems, opening a single aisle (between rows) at a time. By utilizing almost all of the ‘aisle space’ (that has to be left between rows of immobile cabinets), compactors significantly increase the number of cabinets/shelving that can be accommodated within a finite space. What are specimens?

Herbarium specimens are plants that have been collected and preserved for scientific analyses

Specimens include:

Pressed and Dried Plants Dried Plants Plants Preserved in Alcohol-Glycerine or Formalin Solution Plants Preserved in Rocks

What are the processes involved in preparing a herbarium specimen?

You could learn more about the types of specimens from the web-sites: http://www.cgrer.uiowa.edu/herbarium/HerbariaAndSpecimens.htm

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How to prepare a herbarium specimen?

What do use this tool for?

This is called a gardener’s knife. If you want to collect plant specimen you will need this. Apart from this knife you will also need ;

a plant press or vasculum,

blotting papers to dry plants,

trowel to dig and uproot the plant,

collecting and mounting sheets,

gum tape, labels, waterproof ink and pen.

Collecting botanical specimens

Fleshy plants lose their diagnostic features when dried so they are preserved in 4% formalin in glass containers. Gymnosperm cones and dry fruits are collected and preserved as such.

Plants should be collected from various localities for the preparation of herbarium. The herbarium should also have representative specimens from various groups of plants.

A complete specimen when collected should have all the parts including the root system. It is better to collect a plant at its flowering stage. A tag should give the location from where collected. About five or six specimens of each kind of plant should be collected.

The collected plant should either be pressed then and there or collected in a vasculum and pressed later. Vasculum is a metal cylinder with a sliding door in which plants are collected.

Pressing, Drying and Preserving

The collected plant should be pressed between sheets of blotting paper. One plant is arranged on one sheet so that its parts do not overlap. Specimens longer than the sheets can be folded in the form of 'V or N'.

The plant between the sheets is then put in a press for 24 to 48 hours. The press is then opened, blotting sheets changed and plants rearranged again and put back in the press for another 2 or 3 days. The pressed specimen is then dried in sunlight or heat from some other source.

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To prevent the abscission layer formation and decay, plants are killed with formalin or (Mercuric choloride) HgCl or (Carbon tetra chloride) CCl (poisoning). Also dipping in (Mercuric chloride) HgCl (poisoning) saves them from attack by museum pests such as beetles.

Mounting and Labeling

After drying, specimens are mounted on mounting papers or herbarium sheets which are usually of a standard size of 11.5" X 16.5" and sturdy enough to support the dried plants. Glue or adhesive tape or adhesive paste is used to stick the specimens onto the sheets.

Each sheet should carry a label pasted on the lower right hand corner giving the (i) the site of collection, locality and altitude (ii) name of plant (iii) Family (iv) habit (v) date of collection (vi) ecological notes and (vii) name of collector.

Herbarium sheets should be stored in herbarium cases or steel almirahs. They should be arranged according to the system of classification. Moth balls, naphthalene flakes of 2% of Mercuric chloride should be sprayed to keep away mould, fungi and insects.

Specimen Label Information

When you have finally finished preparing a herbarium specimen you got to label it. Each specimen may include information on 1) location, 2) habitat, 3) collector and date of collection, and 4) identification. The first of these, location, is essential. Without locality data, a specimen is worthless!

Location

Collectors must provide adequate, accurate information on locality if specimens are to have lasting value. The following should be included:

country state/province county specific information on how the locality can be reached (distance to nearest town, river crossing, highway intersection or other landmark, and number of the road/highway along which a locality is situated) township, range, section, quarter-section latitude and longitude elevation

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The above can be extracted from state/provincial road maps, county road maps, odometer readings and topographic maps (the latter are available from Geological Survey offices and in the libraries of most major universities, and also commercially on CD-ROM).

Habitat

Information on habitat is useful. This can include a general description of the type of habitat (e.g., forest, rock outcrop, prairie, wetland, etc.); substrate type (e.g., calcareous, siliceous rock), if pertinent; names of associated species; and specific notes on the microhabitat in which the plant was collected (e.g., on exposed soil, on trunk of Quercus macrocarpa 1.5 m from ground, etc.).

Collector and Date of Collection

The name of the collector and collection number, if any, and the date of collection (do not abbreviate; write out name of month and include the century) should be clearly indicated. The names of persons who accompanied the collector may be included in parentheses, but these should be put on a separate line below the collector's name.

Identification

If the specimen has been identified, the name of the species and the person who identified it (if other than the collector) should be included. If the collection is a voucher for a research report or publication, this should be noted (eg., Voucher for Survey of Iowa Fen Bryoflora).

Label Format

The above information, in hand printed (legible!) or typed form, should be given to the herbarium where the specimen(s) will be deposited. These days, it is relatively easy to use a word processing program to set up a simple template that can be used to generate six, standard size (ca. 4" x 3") labels on an 8 ½" x 11" sheet of paper (two columns of three). If a number of labels from a single locality are needed, mail merge programs can be used, and commercial programs also are readily available. Label files can be provided on disk, so that the repository can run the labels on acid-free, pH-neutral paper, using a printer of their choice. The University of Iowa Herbarium uses a Lexmark Z52 inkjet printer because waterproof ink, which may be more permanent than some laser jet inks, is available for that printer. If printed labels are provided to a repository, materials that conform to their standards should be used if at all possible.

University of Iowa Herbarium labels are formatted as per the following example:

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Why Preserve Plant Specimens?

Herbarium specimens are a vital resource because they store a wealth of information. They are utilized by faculty, staff and students in universities, colleges and other research institutions; by personnel from government agencies and conservation organizations; and the general public.

Specimens are utilized for:

o Taxonomic research o Current and historical distributional data o Rare plant list o Identification of ‘unknown’ plants o Generating a ‘search image’ o Locality and ecological information o Genetic data DNA o Voucher specimens

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(b) Wet Preservation

The techniques depend on type of plant: Type of Plant

Method of Preservation

Alga, fungi, soft bodied fruits

Specimen is placed in mixture of 5 cm3 glacial acetic acid, 90 cm3 ethanol (70%), and 7 cm3 formaldehyde (40%).

Plant (general) Specimen is placed in copper (II) sulphate solution (5%) for 24 hours and then immersed in sodium sulphite (0.2 M)

Preservation of Animal Specimen (a) Dry Preservation

Exoskeletons (Skeletons covering the body) such as shell of mollusces, star fish, sea urchins, corals, cocoons of insects sloughed off (cast off) skin of snakes or insects (exuviae), feathers and nests of birds, honey combs and wasp or termite nests, mammalian skin with furs dried sponges etc. can be displayed in the museum intact for many years provided they are prevented from breaking or from attack by insect parasites on microorganisms.

Apart from the above (i) vertebrate skeletons and (ii) pressed insects also form part of dry presentation

Skeleton preparation

Skeletons may be prepared in the following way. Chloroformed vertebrate is dissected to remove organs and as much muscle as possible. Boil the animal so that muscles become tender and remove them. When only the skeleton remains, dip it in Hydrogen Peroxide for bleaching (optional). Mount on a cardboard or wooden board with the help of adhesive like araldite or fevicol and display.

Skull or bones of dead animals collected from the fields may be cleaned with water, disinfected with a disinfectant, dried and displayed in a museum. Stuffed animals are also kept in the museum. Skinning, preserving, stuffing and mounting vertebrates is called TAXIDERMY.

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Stained skeletal preparation

How to collect and preserve insects

Insects are found everywhere - cockroaches abound near the kitchen drains, butterflies roam among flowers while grasshoppers hop and crickets chirp in the grass. Flies are where sweets are and fruit flies hover around vegetables and fruits. Insects are the most numerous and diversified group of animals.

Collection of Insects

Insect collection is an activity which combines fun and study. The equipment required is (i) collecting jar, (ii) a net (iii) fine wire sieves (iv) insect trap

The collecting jar can be of three types

(a) Cyanide bottle: in which sodium cyanide is placed in small lumps in a wide mouthed jar with a well fitting lid. Plaster of pans is made to set on the sodium cyanide. When dry, the bottle is stoppered. Since sodium cyanide is a deadly poison, it has to be handled with care.

(b) Carbon tetrachloride bottle is efficient and harmless. A glass tube is inserted in a small hole bored in the cork of a bottle. A cotton wad is fastened to the cork.

(c) Chloroform bottle has rubber bands placed at the bottom of a bottle and some hloroform put in it. Rubber has the capacity to absorb chloroform. After sometime unabsorbed chloroform is thrown away and a cardboard placed to cover the rubber bands. Fumes of chloroform absorbed by rubber fill the bottle.

A net made of cotton or nylon can be stitched to a handle as shown in the figure.

The fine wire sieves are required to strain the mud which comes with the collected insects or to wash them. Flying insects or walking and hopping insects can be collected from their natural surrounding. Insects may be trapped with the use of insect traps. A simple trap has a large funnel / placed on the mouth of a wide mouthed jar ' containing chloroform or alcohol.

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A Berlese funnel traps small insects. A funnel is soldered at the end of a large can with a hole at its bottom. A false bottom made of wire mesh is placed in the can, filled with leaves and grass and covered with cheese cloth. The stem of the funnel ends in a wide mouthed bottle sealed with cotton plug. This collecting bottle may contain alcohol or chloroform for preserving the insects.

Insects are caught by the net or in the trap and placed in the collecting jar. Then they have to be preserved

Figure19

Where to place the insect pin through the body when mounting insects(Push through area indicated by the black dot)

Insect preservation

Material required for the preservation of collected insects are (i) Pins of various sizes (ii) hard paper (iii) insect spreading board (iv) insect collection box (v) insect cabinet

Before collected insects dry up, pin has to thrust through the thorax or wings (Fig.19). Very small insects are mounted on a triangular piece of hard paper. Wings of butterflies, dragonflies have to be spread out as shown in (Fig. 20 )

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Fig.20 : How to spread butterflies and moths pinned in the spreading.

Spreading of wings is done by first fixing the pin carrying the insect in the groove of the spreading board, wings spread out and strips of paper pinned across wings of either side. Once such mounted insects are dry, they are removed to the insect collection box.

The insects are then classified and arranged in an insect cabinet.

Standard cardboard insect box

Wet Preservation

Invertebrates and small and medium sized vertebrates can be preserved intact in glass or transparent plastic jars of appropriate size called specimen jars (Fig. 21). The jars have a flat, firm base and a lid. A solution of 10% formalin fills the jar. The specimen is mounted on a glass slab of appropriate size which is then placed inside the jar and covered with the lid. The lid may then be screwed on to the jar or sealed on it. From time to time fresh-formalin has to be added or replaced according to need. The specimen remains intact for years if handled properly. The specimens retain their shape and morphology. Only the natural colour is lost.

Fig. 21: Museum jars with preserved specimens

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Wet preservation can be done for (i) intact specimens; (ii) vertebrate embryos; (iii) organs such as heart and eye; (iv) specimens dissected out to display organ systems e.g. nervous system of an animal; and (v) in situ skeletons of small vertebrates such as fish or frog or lizard In it (retained in actual position in the anunal ) skeleton can be prepared in the following manner and mounted and kept in bottles containing glycerine. Chloroformed animal is kept in 90% alcohol in a covered jar for two days. Alcohol is then removed and animal dipped in 1% aqueous solution of Potassium hydroxide till it becomes transparent. The animal is then placed in Alizorin Red Stain (0.1 gm of Alizarin Red in a litre of 1% aqueo.us solution-of KOH). The bones get stained. The animal is then transferred to a specimen jar containing glycerine.

The table below shows how to preserve other animals.

Type of Animal

Method of Preservation

Small mammals First kill with chloroform then preserve in formaldehyde (3%) Frog First kill in a plastic beg and then preserve in formaldehyde

(3%) Snake Inject every 5cm along the body with formaldehyde (3%) and

then preserve in formaldehyde (3%) Fish Preserve in formaldehyde (2%) or ethanol (70%) Insect larva Preserve in ethanol (75-80%) Crab and prawn Preserve in formaldehyde (2%) or ethanol (70%) Snail Kill in water with dilute ethanoic then immersed in formaldehyde

for a few second. Preserved in ethanol (70%) Worm Kill in water with a few magnesium sulphate crystal. Immersed

in formaldehyde (2%) then preserve in ethanol (70%) Leech Kill in hot formaldehyde (45%) and preserve in ethanol (70%) Jelly-fish Kill in magnesium sulphate solution and preserve in

formaldehyde (2%) or ethanol (70%)

TUTORIAL QUESTIONS

Question One

You are teaching Year 3 science in a primary school. You found that there is a lacking of science resources to be used for teaching and learning in the science room. You are thinking of improvising some science resources to help student understand concepts they are going to learn. 1) What are the characteristics you have to consider in improvising resources for

your students’ teaching and learning? 2) Briefly describe the steps involved in carrying out such improvisation.

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3) In what category does the improvised item fall? Bring along the improvised resources and share it with your collogues during your tutorial class. Question Two In every science room or laboratory there should be a log book to record all activities or science practical held. The aim of using a log book is to record any activity regarding to the labs or science room. For safety concern, you have to record all injuries and accidents that happen during science practical sessions. Injury or accident can happen without prior notice. Most accidents and injuries occur due to human ignorance and carelessness while carrying out science activities. Your task:

1. List down all cases of injury and accident that have happened in your school labs since the last 3 year. Then, determine, what are the most frequent injuries or accidents that had happened and suggest the steps that can be taken in order to overcome this injury or accident.

2. List down all the first aid items available in your school science laboratory. Using

appropriate graphic organizer, with specific example, discuss the important of maintenance of these items.

Discuss your answer with your peer in the tutorial session Question Three Prepare

a) wet preservation of a frog or a mice b) dry specimen of a wild plant (a part of a plant or a whole plant). c) Describe your procedures in preparing the preserved specimen

Present and display your specimens during tutorial. Discuss problems that you faced when you collect and preserve the specimens.

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Summary 1 Improvisation should be carried out with a purpose in mind. This is to make sure

when you improvise any resources you only do so after careful consideration so that it is really necessary and worth the effort that you took

2 The usefulness of the resources depends on how you organize and use it during science teaching and learning

3 Proper preparation is needed to ensure the resources used in teaching and learning can easily be accessed by students

4 Commonly, we can divide science teaching and learning resources into four groups namely , teaching aids, science apparatus, science equipments, and science garden/mini zoo.

5 Given the variety of resources available to a teacher, it is important to develop or identify certain criteria for selecting materials

6 The selection of resources could be based on question or criteria like looking at the content, suitability , accuracy of information and the cost.

7 It is the responsibility of the teacher to make sure students’ safety in the science laboratory.

8 Carelessness and cluttered laboratory are two main sources of accident happening 9 General safety rules in the laboratory must be clear and understood 10 Safety measures must always be considered when preparing, and conducting

science activities in or outside the laboratory . 11 All the various science materials like reactive and corrosive materials, radioactive

materials, biological materials and waste product must be handle using the right techniques.

12 Science teachers should be knowledgeable about the procedures in handling dangerous chemicals

13 Managing the laboratory include preparing budget, purchasing and ordering stock, maintenance of laboratory and equipments, write off and disposal of stock.

14 Each personnel in the organizational chart has their own duties and responsibility in managing the science laboratory

15 New science stock are supplied by the Education Ministry 16 Purchasing of stock can be done through central supply or non-central supply in

accordance to the procedures in the relevant circular sent by Education and Finance Ministry

17 Stock keeping should be recorded in the relevant stock book . 18 Write off and disposal of stock procedures should follow the Arahan

Perbendaharaan 314 and 315. 19 Smart science laboratory has a few distinctive characteristics so that science

teaching and learning could be enhance as accordance to smart learning 20 Basic laboratory techniques need to be acquired are glass works, , preparing

standard solution and reagents, and preservation of biological specimens 21 Skills involved in glass works are glass cutting, cutting glass rods and tubes,

bending tubes and making T-joints and polishing 22 Skills in preparing solutions are preparing reagents, standard solution, preparing

solution with specified concentration, and diluting solutions from standard solution 23 Skills relevant to preservation of biological specimens are preservation of dry and

wet preservation for both animals and plants. .

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SYNOPSIS There are two topics in this unit. The first topic will enhance your knowledge and understanding on the use of teaching and learning resources in a science classroom covering aspects such as how to select, prepare and improvise resources when necessary. In the second topic, you will be provided with the knowledge of science equipment and apparatus maintainence, basic laboratory techniques, working procedure and safety in the science laboratory. This will provide you with the skills of managing a science laboratory effectively. LEARNING OUTCOME: Upon completion of this unit, you will be able to:

1. explain the use of the various resources for teaching and learning science from the perspective of improvisation, preparation and selection an appropriate resources;

2. apply the knowledge and skills in maintaining scientific equipment and materials;

3. apply the knowledge and skills in using appropriate safety precautions to carry out

science activities; and

4. acquire some basic laboratory techniques concerning glass works and preservation of biological specimen.

Introduction Effective science teaching and learning in the classroom involve the use of many kinds of resources. Some resources are available in the laboratory and some in the school compound. Besides getting these resources from the supplier, you may need to improvise the resources from unused and discarded materials that may be cheaper and easily available. In this unit you will learn how to improvise simple laboratory apparatus using materials available from the surrounding; make proper preparation in utilizing teaching and learning resources; and reviewing and selecting appropriate learning resources. Improvisation Have you ever made a simple science apparatus by using discarded items such as a plastic drinking bottle? Your initiative in doing this may be due to the need of such apparatus urgently but it was not available in the laboratory for your science activities.

CHAPTER 4 TEACHING AND LEARNING RESOURCES

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Why do we need to improvise? Usually we make an effort to make our own science apparatus or in short improvise such equipment when;

b. the apparatus or equipment available in the market is too expensive; c. the apparatus or equipment available is too expensive and too complex for

student or teacher to use it; d. existing apparatus or equipment is not suitable for students’ science activities; e. there are lacked of apparatus or equipment to perform an experiment; f. we need to produce a devise that can facilitate the teaching of a difficult

concept; and g. we have very limited funds to buy the apparatus or equipment needed.

Improvisation should be carried out with a purpose in mind and not just for the sake of improvising something. Improvisation should not be carried out in a haphazard manner but only after careful study and analysis. Therefore, in order to improvise a science equipment or apparatus, we have to consider the utilization potential of the equipment as follows:

a. the use of the equipment – simple and practical b. how often it will be used – frequent or seldom c. interaction of the materials designed leading to a certain teaching and learning

outcome; d. the worthwhile of the improvised items – is it cost effective and cheap? e. maintenance aspects – easy to repair and to maintain.

The process of improvisation and development of science equipments is summarized in the flowchart below:

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( Adopted from: RECSAM (1978), Laboratory Management and Techniques for Schools and Colleges, Anthonian: Kuala Lumpur) Although the science equipment improvisation starts with an idea, we have to carry out a feasibility study as illustrated in the flowchart above. The aspects that could be included in the study are described in the table below:

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Process

Description Cost-benefit analysis

To find out whether the cost of production of an improvised piece of equipment is worthwhile or beneficial compared with the cost of purchase of a commercially manufactured model.

Necessary Tools

To ensure whether the necessary tools are available or needed.

Necessary Skills

There will be a number of skills necessary (such as woodworking and metalworking) to improvise.

Construction Materials

The main aim of improvisation is to reduce costs. Many discarded materials can be collected and used for improvisation. Choice of materials is often decided by cost and availability.

Process of Construction

The first aim should be for functionality. Once this has been achieved refinements can be made. Workshop and classroom testing are necessary to provide information about improvements. This product becomes the prototype.

Equipment Evaluation

Field testing to detect defects and to find ways of improving it. Among the characteristics considered are: - functionality - internal visibility - reliability - durability - appropriate size - finishing - ease of maintenance - portability and storage - safety

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Normally, there are three categories of science equipment based on their uses in the laboratory that we would consider in making improvisation.

a. Apparatus/instrument – a piece of equipment or set of equipment which when used can establish the validity of a science concept directly.

b. Model – material or one piece of equipment which when properly used can help or facilitate student to understand a concept or concepts through indirect illustration.

c. Support item/scientific material – a piece of equipment that is useful in providing support for science experiment. This material cannot illustrate or establish validity of concept. They are ready for selection to use in carrying out an experiment.

Preparation In order to make teaching of science more meaningful and interesting, a lot of resources had been made available for the science teachers. The usefulness of the resources depends on how you organize and use it during science teaching and learning. To be successful, you need to have a good management strategy in preparing the teaching and learning resources available. Proper preparation is needed to ensure the resources used in teaching and learning can easily be accessed by students. A good science classroom contains a mixture of inexpensive, everyday household materials as well as commercial and noncommercial materials, magazines and books.

Look around your school laboratory, list down which of the science apparatus need improvisation and which can be improvised.

Based on the category described, can you give some examples of the science equipment that can be improvised when necessary?

You have experienced using various teaching aids in your science teaching and learning session. How do you feel if you can’t manage to get any teaching aids when you desperately need it?

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General guide line in preparing and arranging of science teaching and learning resources can be summarized as follows:

i. the resources are placed/displayed at the place where students can see them; ii. keep materials used in investigation readily accessible; iii. keep materials used for making artifacts readily accessible; iv. keep student textbooks, science equipment, and office supplies in readily

accessible areas; v. make sure that students can easily see and hear presentations, discrepant

events or demonstration; vi. position televisions , screens and monitors so that all students have a clear

view; vii. consider height, angle, distance, and glare.

Commonly, we can divide science teaching and learning resources into four groups namely:

i. Teaching aids ii. Science apparatus iii. Science equipments/tools iv. Science garden/mini zoo

Description of each group is shown in the table below:

Resources

Type(s) and example(s)

Preparation/availability

Teaching Aids

a. Simulation materials - model e.g. Human skeleton model; four piston engine model b. Chart and poster – e.g. chart of plant classification; c. Transparency – for visual presentation or process procedure

Choose appropriate materials that may help student understand difficult concept Can get from the supplier, cheap and easy to store Make sure you use the right one – thermal or write-on transparency. There are acetate materials made

What are the teaching and learning resources that are available in your school for science classes? What preparation do you need to carry out before you use any of the teaching and learning resources?

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Resources

Type(s) and example(s)

Preparation/availability

d. Handout – as work sheet or note for further reading

specifically for thermal type equipment- photocopiers and laser printers. It is essential to use appropriate acetate material, or you may end up causing serious damage. Follow the instructions in preparing the transparency. Prepare in advance; must be adequate to student, as a supplement to your presentation, to give your students additional and more detailed information or as worksheets

e. Slide – offer a familiar and less technical way to introduce visual images to supplement classroom presentations. You can have slides made from your own photographs or from overheads that have been produced by hand or using a computer software program e.g. .to show microscopic structure; photo of phenomena or scenario

Choose appropriate slides when needed; when planning to use slides, you need to test the projector prior to using it to ensure that it is in good running order. Lighting will be a factor in using slides effectively as images may require very low levels of ambient light in order to be seen properly. The use of remote control to advance the slides will allow you to move freely about the room.

f. Video tape/film – e.g. to show the event of volcano eruption ( some events still recorded in video tape/film but most has been replaced by VCD)

Plan some sort of preparation or “viewing guide” to focus the students on the purpose of the video and the key points to look for. Then they will follow up with a discussion or concluding remarks that put the video/film into the context of the material being presented.

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Resources

Type(s) and example(s)

Preparation/availability

g.VCD, CD-ROM – e.g supplied by BTP as teaching and learning courseware

Using a video compact disc is similar to using slides or video from a curriculum design point of view. It differs from the others in that the technology may not be as familiar. You will need a VCD player and a T.V. monitor to review sections of the disc and make your decisions about the content you want to use.

h. Multimedia materials – Multimedia is defined as the combination of sound, motion and still pictures and text on one display device particularly a personal computer or a lap-top. e.g. learning ‘portal’ through internet/web- site; any teaching and learning courseware

The same text or images that you have used in overheads and handouts may be used to create multimedia materials. particularly a personal computer or a lap-top. Multimedia equipment required is a computer and a projection device such as LCD panel and a projection screen. Multimedia software package such as power point is also needed to create and display multimedia presentations.

Science apparatus

Science apparatus and equipments for primary

You may get the specification of these

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Resources

Type(s) and example(s)

Preparation/availability

Science equipment/tools

schools are basically simple in nature and easy to use. Apparatus which is made of glass include test tubes, flasks, beakers, lenses, prism, funnel, droppers, magnifying glass, mirror, glass slides, batteries, bulb, etc.

equipment/apparatus in supplier catalog or from PPK.. These items need to be handled with care when using it. Other apparatus and equipment that are also used in primary school are as follow: Spring balance, bar magnet, compass, weights, thermometer, stopwatch, tuning fork, pulleys, meter rule, etc

Science garden/mini zoo/science learning center

Place or place(s) in the school compound or an established learning center outside/nearby school area (such as national zoo, KLCC Petroscience Center) where students can do experiment, investigation and do other activities relating to science teaching and learning. There are a number of characteristics/entities that the science garden should have. How to set up a reasonable science garden/mini zoo in school compound, you may refer to Modul 9: Pengurusan dan Penggunaan Sumber Pengajaran dan Pembelajaran Sains Sekolah Rendah, PuLSaR, published by PPK, 1996. This book should be available in your school.

To carry out science teaching and learning in this place it need to be planned and organized properly. i. set up the objectives of

the activity ii. steps to follow

- no. of students - letter of permission and transport if out side school - determine teaching and learning strategy – experiment, field study, simulation, project work - activity plan – to understand science concept/ investigation process - report writing - presentation - reflection –

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How about aquariums, terrariums and plants that grow in the lab, can they be considered as resources for teaching and learning science?

Can you name the apparatus or equipments labeled in Figure 1 and Figure 2?

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Review and Selection of Resources Do you know how many types of resources that is available to science teachers? What types of resources are most frequently used in your teaching? How do you decide which type of resources is the most effective for teaching a certain difficult concept? Given the variety of resources available to a teacher, it is important to develop or identify certain criteria for selecting materials.

How to select materials?

To decide whether to add a particular book, video, article or other material to the collection, ask yourself:

What is the content? If you have a copy of the material, look at the contents page if it is a publication, or summary information if it is a cassette, etc. If you are using a resource list, look at the list of keywords. The title does not always give a clear indication of what the material contains.

Who is the material for? If you have a copy of the material, look at the foreword or introduction, summary information if it is a cassette, or accompanying description. If you are using a resource list, look at the description of the material. Decide whether the material is intended for the people your resource centre is serving. For example, an academic textbook on drug abuse would not be useful for a nurse who wanted practical information about drug abuse for health education work in a secondary school. Similarly, a video on disabled people’s rights which was filmed in Africa might not be useful for an Asian audience.

Is the information accurate and up-to-date? Look at the date of publication. If it was more than five years ago, think carefully before ordering it. As a general rule, avoid purchasing anything more than five years old. The exception may be some key textbooks or audiovisual materials.

How much does it cost? Look at the price, if shown. Consider whether the material is worth the money and whether funds are available. Consider whether you may be able to request a free copy.

Does the resource centre lack materials on this subject? Look at what else you have in your resource centre on the same subject. Does the material fill a gap? Will it improve the collection on this subject?

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How to obtain materials?

You have selected that particular resource is suitable. The next step is how to obtain them?

The main ways are:

gifts and exchanges purchasing document delivery services.

Gifts and exchanges Many organisations provide materials free or in exchange for other materials. Accept only those that will be useful. Do not accept any materials that are on a subject of no interest to resource centre users, or that are old or in poor condition. To obtain free materials, write a brief letter outlining your request. You can either type a new letter for each request, or you could photocopy a standard letter which has spaces for you to write in the details. Purchasing The procedure for purchasing materials needs to follow your organisation’s financial and accounting regulations. Procedures for purchasing standard items, such as stationery or fuel, may not be suitable for purchasing materials for the resource centre. You may need to develop a procedure for ordering materials, in consultation with the resource centre advisory committee, managers and finance staff. Books and manuals can be ordered directly from publishers or distributors such as bookshops, specialised booksellers and library suppliers (which supply to libraries but not the public). You can place an order by post, telephone, fax, e-mail or personal visit, depending where the supplier is and what facilities are available. Audiovisuals can be ordered in the same way as books. Remember that there are several different video systems, such as NTSC, PAL and SECAM. Unless you have a multi-system video player, you will need to know which system your video player uses, and check that the video you want is available in that system. When you order, remember to state which video system you require. Periodicals (newsletters, magazines and journals) are normally ordered direct from the publishers, or through subscription agents. You can ask for a sample copy before taking out a subscription. This will help you to decide whether the periodical will be useful.

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Document delivery services Document delivery services enable you to obtain photocopies of articles or borrow materials. They are useful for obtaining key journal articles without taking out a subscription, or consulting a publication or chapter of a book to assess whether it would be useful to include in your collection. They are especially useful for materials that are expensive or not essential to the collection, for example, for users carrying out specialist research. Document delivery services are usually provided by libraries and documentation centers via an inter-library loan (ILL) scheme. Some organisations will lend whole materials, such as books and videos. Others will only provide photocopies of part of a publication. Remember to check what service is on offer. There is usually a charge, unless you are part of a network of cooperating information services. You can obtain details of document delivery services from national library services, local library networks, other resource centers working in the same subject area, current awareness services or e-mail discussion groups. You could also use the following suggested criteria for selecting resources with consideration given to students’ cognitive and affective development.

Cognitive and Affective Aspects Criteria for selecting resources

Knowledge retention Presents the topic in a manner relevant to students’ everyday lives

Motivation for Learning Graphic media must be attractive and clearly seen by students

Uses technology as a tool to enhance learning

Quality of narration and background music for audiovisual material must be appealing.

Knowledge Transfer Integrates science across subject areas Presents accurate information Stresses exploration and depth over

coverage of information Assimilation and Perception Lets students engage in direct, purposeful

experiences in which they can make their own observations and conclusions

Help students to construct understanding of concepts

Thinking and Reflection Promotes inquiry, problem solving and critical thinking

Allows students to explore a science topic in depth

Readiness for Learning Vocabulary and clarity of concept matches the readiness levels of the students

Instill Positive Values and Attitudes Contain activities such as simulation, role-play, drama etc where good moral values and right attitudes can be integrated.

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Archenhold W.F., Jenkins E.W. & Wood-Robinson C. (1977). School Science Laboratories.

London: John Murray. Bahagian Pendidikan Guru, Kementerian Pendidikan Malaysia. (2001). Modul Pengajaran

Sains Sekolah Menengah (Kursus Dalam Perkhidmatan Enam Minggu). Bahagian Pendidikan Guru: Kuala Lumpur.

Bahagian Pendidikan Guru, Kementerian Pendidikan Malaysia. (2003). Sukatan Pelajaran

Science Major (Kursus Perguruan Lepas Ijazah-Sekolah Rendah). Bahagian Pendidikan Guru: Kuala Lumpur.

Esler W.K. (2001). Teaching Elementary Science (A full spectrum science instruction

approach) U.S.A. Wadsworth Thomson Learning. Glencoe Science Professional Series. United States of America: McGraw-Hill Componies. Joseph S. Krajcik (2003). Teaching Science in Elementary & Middle School Classroom – A

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Keselamatan Makmal Sains Sekolah. Kuala Lumpur. SEAMEO RECSAM. (1978). Laboratory Management and Techniques for Schools and

Colleges. Kuala Lumpur: Anthonian Store Sdn. Bhd. Wadsworth Group Thomson Learning Inc. William K. Esler & Mary K. Esler (2001). Teaching Elementary Science U.S.A.

Oops!! That’s the end.

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