Topic 7 Manipulative Skills I

8/13/2019 Topic 7 Manipulative Skills I

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INTRODUCTION

Figure 7.1:Finding the boiling points of various liquids

LEARNING OUTCOMES

By the end of this topic, you should be able to:1. Explain the meaning of manipulative skills;

2. Discuss the skill of using and handling science apparatuscorrectly;

3. Discuss the skill of handling non living and living specimenscorrectly; and

4. Discuss the skill of cleaning science apparatus correctly.

TTooppiicc

77Manipulative

Skills I

How do I read the

scale?


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TOPIC 7 MANIPULATIVE SKILLS I 115

A group of pupils are doing an investigation to find the boiling points ofdifferent liquids (see Figure 7.1). They do not know how to read the scale on thethermometer. Will they be able to carry out the investigation successfully?

Being able to read the scale on the thermometer is an example of a manipulativeskill. In this topic and the following topic, we are going to explore themanipulative skills that pupils need to acquire in order to be able to carry outscience investigations effectively.

WHAT ARE MANIPULATIVE SKILLS?

Manipulative skills are psychomotor skills that enable you to carry out thepractical work in science. It involves the development of hand-eye coordination,such as focusing a microscope, sketching specimens, measuring angles andcutting glass.

Pupils must be able to use and handle equipment in order to do investigation inthe science laboratory. You may need to use special equipment in someinvestigation. You need to follow certain techniques when handling this specialequipment. Therefore, it is important to develop manipulative skills in thelaboratory.

Physical practice with laboratory equipment provides concrete experiences withthe apparatus and procedures. The pupils need to use and handle the realequipment in order to acquire the skill. For example, pupils need to use andhandle the beam balance so that they would be able to acquire the skill to

measure the mass of objects. These experiences provide first-hand exposure tothe equipment.

Can you remember studying the definition of manipulative skills in Topic 1?Manipulative skills are hands-on skills that you need when you are doing scienceactivities. You use different science equipment to test hypotheses and drawconclusions on any given problems. These tools can vary from things you seearound you every day, such as beakers, test tubes, to calibrated and preciseinstruments that can be very sensitive such as thermometers and ammeters.

7.1

ACTIVITY 7.1

Does the word "manipulative give" a clue as to what it means? Discuss it.


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TOPIC 7 MANIPULATIVE SKILLS I116

The science manipulative skills as stated in the Malaysian school sciencecurriculum are given below:

(a) Using and handling science apparatus and materials properly.

(b) Handling living and non-living specimens properly and carefully

(c) Drawing specimens, apparatus and materials accurately.

(d) Cleaning science apparatus in the correct manner.

(e) Storing science apparatus and materials accurately.

THE IMPORTANCE OF ACQUIRINGMANIPULATIVE SKILLS

Accidents can happen anywhere even in a science laboratory. It can occur due tonegligence, faulty instruments or because pupils have not acquired the necessarymanipulative skills required in a science laboratory. Thus, it is important forpupils to acquire these manipulative skills.

Other reasons why it is important for pupils to acquire these skills are as follows:

(a) To ensure the success of the experiment when collecting data for theexperiment. Data collected needs to be accurate and precise.

(b) To achieve accuracy and precision, pupils need to be able to use scienceapparatus. For example, if they need to measure the temperature of asolution, but do not know how to use and handle the thermometer they willnot get accurate readings.

(c) To be able to communicate the results or observations of the experiment.Important details might be missing or misunderstood if diagrams are notlabelled properly.

(d) Knowing how to clean and store apparatus helps to prolong the shelf-life ofthe apparatus especially if it is expensive and sensitive. Careful maintenancealso safeguards the accuracy of the instrument.

(f) Storing chemicals properly also affects the accuracy of readings. pH paperexposed to air might not be able to show proper results anymore. Ifchemicals are not properly stored they could cause fires. If living specimenare not handled properly, minor injuries or cuts could occur. This could befatal for someone who has haemophilia because for this pupil a minor cutcould lead to serious injury.

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USING AND HANDLING SCIENCEAPPARATUS AND MATERIALS PROPERLY

What does it mean when you say you are able to use and handle scienceapparatus and materials? Using science apparatus and handling scienceapparatus are two different skills.

7.3.1 Using Science Apparatus Properly

Using science apparatus means you know which appropriate instrument to usein a certain situation and know how to read the scale on the instrument that youare using.

Study the following example of how you should use glassware.

7.3

ACTIVITY 7.2

Study the picture in Figure 7.2 below. Describe what could happen in thisscience laboratory.

Figure 7.2:Scenario in a science laboratorySource:http//:www.heumann.org/u1/lab.jpg


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When using glassware, you should:

(a) Use the correct type of glass for heating.

(i) Make sure to use only glassware made of borosilicate glass (Pyrexbrand or Kimax brand). Common glass can break, explode or shattervery easily when subjected to heat shock.

(b) Use glassware only for its intended purpose (see Table 7.1)

Table 7.1: Glassware and Its Intended PurposePurpose Glassware

Measuring volume Pipettes ,burettes ,graduated cylinders,

volumetric flasks, dropper pipettes

Storing solids and liquids Bottles, vials

Holding reactive chemicals duringexperiments

Beakers, flasks, test tubes, watchglasses, test plates

Transferring liquids and gases Glass tubing, funnels

Measuring temperature Thermometers

Let us now look at how you should use the microscope.

MicroscopeWhen moving your microscope, always carry itwith both hands (see Figure 7.3). Grasp the armwith one hand and place the other hand under thebase for support.

Turn the revolving nosepiece so that the lowest

power objective lens is "clicked" into position(This is also the shortest objective lens).

Your microscope slide should be prepared with acoverslip or cover glass over the specimen. Thiswill help protect the objective lenses if they touchthe slide. Place the microscope slide on the stageand fasten it with the stage clips. You can pushdown on the back end of the stage clip to open it.

Figure 7.3:Carrying the microscope


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Look at the objective lens and the stage from the side(see Figure 7.4) and turn the coarse focus knob sothat the objective lens moves downward (or the

stage, if it moves, goes upward). Move it as far as itwill go without touching the slide!

Figure 7.4:Right technique to focusNow, look through the eyepiece and adjust theilluminator (or mirror) and diaphragm (see Figure

7.5) for the greatest amount of light.Slowly turn the coarse adjustment so that theobjective lens goes up (away from the slide).Continue until the image comes into focus. Use thefine adjustment, if available, for fine focusing. If youhave a microscope with a moving stage, then turnthe coarse knob so the stage moves downward oraway from the objective lens.

Move the microscope slide around so that the imageis in the center of the field of view and readjust themirror, illuminator or diaphragm for the clearestimage.

Now, you should be able to change to the nextobjective lenses with only minimal use of thefocusing adjustment. Use the fine adjustment, ifavailable. If you cannot focus on your specimen,repeat steps 4 through 7 with the higher powerobjective lens in place. Do not allow the objectivelens to touch the slide!

The proper way to use a monocular microscope is tolook through the eyepiece with one eye and keep theother eye open (this helps avoid eye strain). If youhave to close one eye when looking into themicroscope, it is ok. Remember, everything isupside down and backwards. When you move theslide to the right, the image goes to the left!

Do not touch the glass part of the lenses with yourfingers. Use only special lens paper to clean thelenses.

Figure 7.5:Adjusting to get morelight


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When finished, raise the tube (or lower the stage),click the low power lens into position and remove

the slide.

Always keep your microscope covered when not inuse. Dust is the number 1 enemy of the microscope!

Source:www.microscope-microscope.orgLet us now look at how you should use a measuring cylinder.

Measuring CylinderThe measuring cylinder comes in manydifferent sizes so that we can use them tomeasure small and large volumes of liquid(see Figure 7.6)

Figure 7.6:Measuring cylinderIt is important to choose the correctmeasuring cylinder for the volume youwish to measure (see Figure 7.7)

Figure 7.7:Suitable measuring cylinder


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It is also important to take a careful lookat the graduation scale on the measuringcylinder before you use it. Make surethat you know which volume isrepresented by the distance between twoadjacent graduation marks (see Figure7.8).

Figure 7.8:Correct technique to read thescaleon the measuring cylinder

Always leave the measuring cylinder ona flat surface when you are reading thevolume of the liquid it contains. Youshould move your body downwards sothat your eye is on the same horizontalline as the surface of the liquid. Find themeniscus of the liquid. The top of theliquid will form a depression inside thegraduated cylinder. The lowest point ofthe depression is the meniscus. Locate

the graduated mark corresponding tothe meniscus. If the meniscus is notaligned with a marking, find themarking closest to the meniscus (Figure7.9).

Figure 7.9:Meniscus

DO NOT lift the measuring cylinder tomeasure the volume of the liquidcontained in it! (see Figure 7.10)

Figure 7.10: Wrong technique to read thescale on the cylinder

Source : http://www.saburchill.com/chemistry/chapters/chap0021.html


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7.3.2 Using Science Materials Properly

As a science teacher, you must have adequate knowledge of the materials thatyou are going to use in the laboratory. This is important because you might causeinjury to you and your pupils if you do not use the materials properly. Somematerials are flammable, corrosive or produce harmful gas when heated. Thus,make sure you find out more about the materials before you use them in thelaboratory.

7.3.3 Handling Apparatus or Materials Properly

Handling apparatus or materials properly means following certain procedures orconsidering certain things when using them. Some examples are given below:

(a) When you are using the thermometer in an experiment, you should nothold the body of the thermometer.

(b) You should not use the thermometer to stir anything.

(c) The bulb of the thermometer should not touch the base of the beaker.

(d) When you are heating liquids in a test tube, use a small flame and movetest tube constantly.

(e) Always make sure the mouth of the test tube does not point towardsanybody when heating.

(f) When you want to heat a combustible substance, you should not heat itover a direct flame but in a water-bath.

(g) Pick up materials using forceps or spatula and not with your hands.

(h) Never handle broken glass with your bare hands. Use a brush and dustpanto clean up broken glass. Place broken glass in the designated glass disposalcontainer.

ACTIVITY 7.3

True or False1. A 10ml graduated cylinder with 0.1ml markings would be

preferable for a 5.0ml sample of liquid.

2. A 100ml graduated cylinder would be better suited for a 50mmlsample of liquid.


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(i) Examine the glassware before each use. Never use chipped, cracked ordirty glassware.

(j) Do not immerse hot glassware in cold water. The glassware may shatter.

Study the pictures below. List down how these pupils handle scienceapparatus and chemicals in the laboratory. Discuss how you can correctthem.

ACTIVITY 7.4


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HANDLING LIVING AND NON-LIVINGSPECIMENS PROPERLY AND CORRECTLY

What is a specimen? If you look it up in a dictionary, it refers to "an individualanimal, plant, piece of a mineral, etc., used as an example of its species or type forscientific study or display". So if you are observing animals in an investigation,then animals are the specimen. If you are examining types of rock, then rock isthe specimen. Thus specimen could be a living or non-living specimen.

What are the usual living specimens that are used in your science class? Inprimary schools, we usually do not use many live specimens. You might observeparts of a plant leaves, flowers, fruits, roots or the whole plant itself. The usualpractice is that rather than cutting parts of the plant or uprooting the whole plantwe do the observation in the field itself. If it is necessary to get the plant into theclassroom, then do so and then return the specimen to the field again. Do notthrow the specimen into the dustbin.

Do you notice the following?

(a) Some plants produce gum or oil that is poisonous or could cause an allergicreaction characterised by an itchy rash, bumps and blisters when they comein contact with skin.

(b) All parts of some plants are poisonous as these contain sap that can irritatethe skin and eyes e.g. oleanders.

(c) Some plants have thorns or spines e.g. cactus.

(d) Some plants can cause harm when ingested, for example hy r ngeblooms will cause stomach pain if ingested and possibly itchy skin,

7.4

Hands-on ActivityMeasure the following objects and record the measurements using the

correct unit of measurement:

(a) Diameter of a ball bearing

(b) Length of paperclip

(c) Diameter of a test tube

(d) Diameter of a wire

(e) Mass of a ring


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weakness and sweating as well as a possible breakdown in the bodysblood circulation.

So you need to choose plants that are safe to be handled by all pupils but if youneed to use "dangerous" plants, then remind your pupils to be careful whenhandling them.

What about animals? What animals do you normally bring to class?

You might be doing activities with small animals such as cockroaches,earthworms, snails, fishes or frogs. How do you make sure the class does not getchaotic? If you are asking the pupils to study live cockroaches or grasshoppers,place them in closed petri dishes and then ask them to do the observation. Whatdo you do with the animals after the activity? If the animals are still alive, releasethem in nature. If the animals are dead, place them in plastic bags, tie them upand discard in the dustbin. The laboratory assistants would know what to donext.

You also need to be aware if your pupils are allergic to fur-bearing animals, likecats and mice. Then, these pupils need to use latex gloves and a respiratory maskwhen handling them.

The following are a few simple rules which need to be followed to ensure safety:

(a) Handle all animals with care and respect.

(b) Use hand lens to examine small animals.

(c) Use forceps to collect small animals.

(d) Avoid killing and injuring animals.(e) Wear gloves when handling animals.

(f) Before starting work, cover all wounds.

(g) Animal bites can usually be avoided if pupils are kept in a small group.

(h) Rough play or teasing should absolutely not be allowed.

(i) Children should not be allowed to feed animals directly from their hands.

Do not handle poisonous plants


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(j) Small animals such as rabbits and hamsters should be handled gently, theymight bite if they feel threatened.

Children should be discouraged from "kissing" animals or getting in close contactwith their faces.

Hands must be thoroughly washed with soap.

If bitten, treat the wound with antiseptic and seek medical help if necessary.

Hands-on Activity

Figure 7.11: A vivariumSource: http://www.amphibiancare.com

A vivarium is an enclosure forkeeping or raising and observing

animals or plants indoors (Figure7.11).

Frogs are an example of animalsthat could be useful to keep in thelaboratory as you could use them asa resource to teach pupils about thephysical characteristics and lifecycles of animals.

Find out how to build a vivariumfor keeping frogs and then constructthe vivarium. Keep the vivarium sothat your pupils can observe themand write a report on the life cycleof a frog.

ACTIVITY 7.5

1. What are some examples of non-living specimens that are used in a

primary science classroom?

2. Are there special considerations when you need to handle them?


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CLEANING SCIENCE APPARATUSCORRECTLY

Science apparatus are made up of different materials. As you know, cleaningglassware is not the same as cleaning plastic apparatus.

Let us look at how to clean glassware first.

You should use the following steps to clean glassware when there is no soluteresidue present on the glassware:

(a) Rinse the glassware with distilled water.

(b) Scrub inside the glassware, using a scrub brush of the correct diameter to fit

inside the container.

(c) Rinse the glassware with distilled water.

(d) Scrub inside the glassware, using scrub brushes.

(e) Rinse the glassware with distilled water.

(f) Set the glassware aside to dry.

If there is solid residue present you should try to clean the residue first with apaper towel and then submerge the glassware in an Alconox solution for several

minutes. Later scrub the glassware, using a scrub brush, rinse the glassware threetimes, using distilled water. Finally, set the glassware aside to dry.

You usually use plastic ware when you are teaching Year 1 and 2 so as to preventbreakage. Plastic ware is more sensitive than glassware and a mild laboratorydetergent is enough to clean it. Note that the detergent must have neutral pH, benon-abrasive and non-caustic. Rinse with clean, preferably distilled water. Useheat and chemical solutions for removing difficult grease, oil and other organicmatter. However, not all types of plastics can withstand heat and chemicalapplication. It is still best that you check the cleaning instructions in the

7.5

ACTIVITY 7.6

Find information how to clean glasswares that have stubborn stainedresidue on them. You could go to this website:

http://www.ehow.com/how_7812394_clean-laboratory-apparatus.html#ixzz1vbamahoo


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packaging. If you have apparatus made of platinum, you could use the followingtips to clean them:

(a) If the platinum dish or crucible has organic matter, clean it with a chromic

acid mixture.

(b) If it was used to contain insoluble carbonates or metal oxides, the platinumdish must be boiled in a solution of hydrochloric acid, rinsed thoroughly,and boiled in nitric acid.

(c) Platinum electrodes are cleaned with water followed by alcohol.

Finally, if you have apparatus made of stainless steel, you could use thefollowing tips to clean them:

(a) Alkaline, chlorinated alkaline and non-chloride cleaners could be used toclean them.

(b) Never use hydrochloric acid on steel products.

(c) These solutions must be applied on the equipment using non-abrasivetools. A soft and clean cloth can be used.

(d) Stainless steel pads also can be used.

(e) Filtered water is the recommended liquid for rinsing.

Science instruments need to be cleaned before storage and usually the

instructions for cleaning are provided when you buy them. You could also referto the science laboratory manual if instructions are not provided.

Hands-on ActivitiesDo the following activities.

(a) Find out how to clean the:

(i) Objective and eye piece of a microscope.

(ii) Pan of triple beam balance.

(iii) Wires used in an electric circuit.

(b) Clean them as suggested from the information that you have gathered.


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Manipulative skills are psychomotor skills that enable you to carry outpractical work in science.

It involves the development of hand-eye coordination, such as focusing on amicroscope, sketching specimens, measuring angles and cutting glass.

The science manipulative skills as stated in the Malaysian school science

curriculum are given below:

Using and handling science apparatus and materials properly.

Handling living and nonliving specimens properly and carefully. Drawing specimens, apparatus and materials accurately.

Cleaning science apparatus in the correct manner.

Storing science apparatus and materials accurately.

There are many reasons why it is important to acquire manipulative skills.Acquiring these skills would:

ensure the success of the experiment.

achieve accuracy and precision when measuring.

communicate the result or observation of the experiment.

prolong shelf-life of the apparatus.

To be able to use an apparatus means you know which appropriateinstrument to use in a certain situation and know how to read the scale on theinstrument that you are using.

There are certain procedures or considerations that you need to take note

when you handle apparatus or materials.

Choose plants that are safe to be handled by all pupils in the laboratory. If

you need to use `dangerous plants then you need to remind your pupils to

be careful when handling them.

There are also a few simple rules to follow when handling animals in thelaboratory.


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Cleaning glassware would be different from cleaning plastic apparatus

Rinse apparatus with water if they are not so dirty. You could also use mild

detergent to clean them if they are quite dirty. Soak them overnight in soapywater if necessary.

It is still best that you check the cleaning instructions in the packaging.

Cleaning apparatus

Living specimens

Non-living specimens

Manipulative skills

Use and handle apparatus

Bailer, J., Ramig, J.E, & Ramsey, J.M (1995). Teaching process skills.USA: GoodApple.

Fiel, R.L, Funk, H.J, Rezba, R.L, & Sparague, C. (1995). Learning and assessingscience process skills. Iowa: Kendall/Hunt Publishing Company.

How to clean laboratory apparatus. Retrieved Jun 14, 2012, from http://www.ehow.com_7812394_clean-laboratory-apparatus.html#ixzz1vbamahoo.

How to take of care of science equipment. Retrieved Jun 12, 2012., fromhttp://www.howtodothings.com/education/how-to-take-care-of-science-equipment.

Skamp, K. (ed) (2004). Teaching primary science constructively. Melbourne:Thomson Learning

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Topic 7 Manipulative Skills I