mandatory experiments science notes jc-learn jc …...1. use forceps to take small piece of inner...

Mandatory Experiments Science Notes JC-Learn

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JC-Learn Science Notes Higher Level

Mandatory Experiments


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Mandatory Experiments

This folder includes every single experiment, which you must complete throughout the course. You must then write up these experiments in your experiments book and this is worth 10% of the exam.

Biology

Mandatory Experiment *To investigate the variety of living things by direct observation of plants and animals in their environment. To classify living things as plants or animals, and animals as vertebrates or invertebrates. Materials needed: Plant and animal identification books, plant and animal keys, notebook and pencil Method

1. Select area (school grounds) 2. Look for as many examples of plants and animals as you can

find 3. Using identification books and keys, identify and name three

plants and three animals within the area 4. Note which animals are vertebrates and which are

invertebrates 5. Record the information

Method

1. Use forceps to take small piece of inner skin of onion 2. Put drop of water onto glass slide, put piece of onion skin onto

drop of water on slide 3. Lower cover slip over the onion skin (protects microscope

lens) 4. Put slide onto microscope stage, under the clips 5. View the slide through the lens


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6. Draw and label diagram of few cells under low power, then under high power

7. Remove slide from stage 8. Put drop of iodine stain under cover slip (stains the cytoplasm

into yellow/brown colour) 9. Again examine under microscope, draw labeled diagram of this

Mandatory Experiment 4 parts

* (a) To test for the presence of starch. Apparatus needed: 2 test tubes, droppers, iodine solution, starch solution Method

1. Put 2cm3 starch solution in test tube 2. Put same volume of water in other test tube 3. Add two drops of iodine solution to both 4. Shake tubes, note colour change 5. Record results 6. Iodine is blue with starch, brown/yellow without it

*(b) To test for presence of a reducing sugar (glucose) Apparatus needed: 2 test tubes, droppers, water bath, tripod, gauze, Bunsen burner, tongs, glucose solution, Benedict’s solution


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Method

1. Set up apparatus with water and benedicts solution in one, and glucose and benedicts solution in the other

2. Stand test tubes in boiling water bath for five mins 3. Record colour changes

Results

Tube with glucose solution goes brick-red colour, tube with water stays blue.

Conclusion

Appearance of brick red colour shows reducing sugar is present

* (c) To test for presence of protein Apparatus needed: 2 test tubes, droppers, sodium hydroxide solution, copper sulfate solution, protein solution eg. milk Method

1. Set up two test tubes with milk and sodium hydroxide solution in one, and water and sodium hydroxide in the other

2. Add three drops of copper sulfate solution to each tube, mix the contents


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Results Mixture with milk turns violet coulour. The second test tube

with only water stays blue. Conclusion

Protein present in mixture with milk, not present in mixture with water.

* (d) To test for the presence of fats Materials needed: brown paper, butter Method

1. Label two pieces of brown paper A and B 2. Rub butter on A 3. Put drop of water on B and rub it in 4. Allow both pieces of paper to dry 5. Hold each piece up to light, compare amount of light that

passes through Results

Place on paper where butter was rubbed will allow light pass through – translucent spot.

Conclusion

Fat is present on paper rubbed with butter. There is no change in paper rubbed with water – no light passes through it (fat not present).

Mandatory Experiment

To investigate the conversion of chemical energy in food into heat energy

Apparatus needed: Bunsen burner, mounted needle, thermometer, boiling tube, graduated cylinder, retort stand, balance, cracker

Method

1. Put 20cm3 water in test tube 2. Record temperature of water using thermometer 3. Stick mounted needle into cracker


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4. Hold cracker in Bunsen flame until it catches fire 5. Transfer burning cracker under the water in boiling tube 6. Take temp of water again when cracker has burnt out 7. Record new temperature

Result

The temperature of the water will have risen. Conclusion

The chemical energy in the cracker is converted into heat energy. Food contains energy.

Mandatory Experiment *To investigate the action of amylase into starch. Apparatus required: droppers, graduated cylinder, Bunsen burner, tripod, gauze, beaker, thermometer, 4 test tubes, tongs, starch solution, amylase solution, iodine solution, Benedicts solution. In this experiment we want to see if amylase will break down starch. Method

1. Set up apparatus – two test tubes , one with starch and amylase while another has starch and water, placed in water bath at 37 degrees Celsius.

2. Leave both test tubes for five mins 3. Remove test tubes and place in rack 4. Place half contents of A into test tube C 5. Test contents of A for starch by adding iodine 6. Test contents of C for reducing sugars using Benedicts solution 7. Put half contents of B into test tube D 8. Repeat starch and reducing sugar tests on contents of B and D.

Result

It is only in test tube with amylase that starch has been broken down.

Conclusion

Amylase breaks down starch to reducing sugar.


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Mandatory Experiment *To compare the carbon dioxide levels of inhaled and exhaled air Method

1. Set up two test tubes, both with limewater – one with a tube coming out to suck in from and one with a tube coming out to blow out

2. Hold tube A (suck in from this one) and tube B (blow out from this one)

3. Suck in through tube A 4. Breathe out through tube B 5. Repeat steps until limewater in one goes milky and record

result Result

The limewater in test tube B turns milky quicker than A Conclusion

The level of carbon dioxide in exhaled air is greater than the level of carbon dioxide in inhaled air


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*To show that starch is produced by a photosynthesising plant. Apparatus required: beaker, Bunsen burner, tripod, gauze, forceps, test tube, white tile, alcohol, iodine solution, pot plant Method

1. Put pot plant in dark for 48 hours. This is necessary to de-starch the plant (without light, the plant cannot make any food and uses up its store of starch).

2. Cover part of some of leaves with aluminium foil 3. Leave plant in bright light for four to six hours (allows plant to

photosynthesise). 4. Set up water bath with leaf in boiling water. 5. Remove one of the leaves with a foil strip and draw sketch of it

to show position of foil strip. 6. Remove foil strip, drop leaf in boiling water for one minute to

kill it. 7. Turn off Bunsen burner. 8. Half-fill a test tube with alcohol and push leaf into this test

tube. 9. Stand test tube in warm water for ten minutes (chlorophyll

removed so it is easier to see reaction of starch with iodine solution).

10. Use forceps to remove leaf from test tube (leaf will be white in colour).

11. Dip leaf in warm water to soften it. 12. Spread leaf onto white tile and cover with iodine solution (tests

for presence of starch). 13. Draw new diagram of leaf showing where starch is present and

compare it to first diagram. Results

Part of leaf in light turns blue-black with iodine solution (shows starch is present).

Part of leaf that was covered by foil stays brown-yellow (colour of iodine). This shows starch is not present.

Conclusion


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Starch only found in part of leaf exposed to light. Therefore starch is produced by photosynthesis.


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Mandatory Experiment *To investigate the conditions necessary for germination. Apparatus required: 4 test tubes, cotton wool, cress seeds, oil, cool boiled water. Method

1. Set up four test tubes, as shown in the diagram, with cress seeds in each tube.

2. Boiling the water used in test tube C removes the oxygen from it. The layer of oil prevents oxygen getting back into the water.

3. Put test tubes A,C and D in warm place for a week. 4. Put test tube B in fridge for week.

Results

Test tube A: the cress seeds germinate. These seeds have all the conditions for germination.

Test tube B: The seeds do not germinate. They have no warmth. Test tube C: The seeds do not germinate. They have no oxygen. Test tube D: The seeds do not germinate. They have no water.


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Mandatory Experiment * (a) To study a local habitat Method

1. Make map of habitat. 2. Record environmental factors affecting habitat. 3. Collect and identify plants and animals in habitat. 4. Use quadrat to examine variety of organism present. 5. Use line transect to investigate distribution of organisms

across habitat. 6. Use the information to find examples of food chains, food webs,

competition, adaptation and interdependence in the habitat. *(b) To show the variety of plants in habitat using a quadrat. Apparatus required: quadrat, pen, recording sheet, and plant key Method

1. Throw pencil over shoulder at random 2. Place quadrat where it lands 3. Record plant types inside quadrat boundary 4. The quadrat should be thrown ten times to get accurate results 5. Use information gathered to calculate percentage frequency of

particular plant 6. Use results to draw bar chart, to make your results easier to

understand


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* (c) To investigate the distribution of plants using line transect.

Apparatus required: length of rope marked off at intervals, recording sheet, pen, plant identification book and key Method

1. Lay marked rope across area of change in the habitat. Mark this line on your map of the habitat.

2. Record name of any plant which touches/ is under the rope at each station.

Mandatory Experiment * To investigate the presence of micro-organisms in air and soil. Apparatus required: 3 sterile Petri-dishes (each with sterile nutrient agar as this is a suitable food for micro-organisms), inoculating loop, Bunsen burner, incubator, sample of soil, marker pen Method

1. Label the three Petri-dishes with nutrient agar A,B and C (the dishes and agar are sterile which means there are no organisms present).


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2. Lift lid off dish A and leave in lab for ten minutes. This exposes the agar to the air. Then put the lid back on.

3. Heat the inoculating loop in Bunsen burner to sterilize it. Allow cooling. Open lid of dish B and sprinkle soil across surface of agar.

4. Leave dish C unopened. This dish acts as a control. 5. Put dishes, upside down, in incubator at 25 degrees celcius for

2 days. The dishes are placed upside down to prevent condensation from blocking our view of micro-organism that grow.

Results

Bacteria grow in groups/colonies of many thousands of cells. These can be seen as shiny blobs on agar surface. Fungi tend to appear as fluffy, hairy or mouldy growths.

Dish A has bacterial and fungal colonies that are visible. Dish B has bacterial and fungal colonies that are visible around the clumps of soil. Dish C has no growths present.

Conclusion

There are micro-organisms present in air and soil.


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Chemistry Mandatory Experiment * To grow crystals of alum or copper sulfate. Apparatus required: pestle and mortar, stirring rod, Bunsen burner, tripod, wire gauze, evaporating basin, thermometer, copper sulfate, water Method

1. Grind up sample of copper sulfate with pestle and mortar 2. Add powdered substance to 100cm3 of water in beaker. Use

stirring rod to help it dissolve. Continue adding until the solute no longer dissolves. Note the temperature of the water.

3. Heat water to about 60 degrees celcius and not what happens to undissolved copper sulfate. Add in more copper sulfate and heat until no more will dissolve.

4. Pour half of the solution into warm evaporating basin and put aside to cool slowly. Cool other half quickly by holding the beaker under running water from tap. Note what you observe.

5. Compare size of crystals obtained by slow cooling of hot solution with size of those obtained by fast cooling.

Result

Crystals are formed Conclusion

Crystals are formed when a hot concentrated solution is cooled


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Mandatory Experiment * To separate a mixture of water and soil using filtration. Apparatus required: filter paper, filter funnel, glass rod, retort stand and clamp, conical flask, mixture of water and soil Method

1. Take filter paper and fold into cone shape 2. Place cone of filter paper into filter funnel 3. Set up apparatus as shown in diagram. Pour some mixture

down glass rod and into filter funnel. 4. Keep adding mixture until it is all filtered. 5. Open filter paper and allow soil to dry

Result

The solid remaining on filter paper is called the residue. In this case, soil is the residue. The clear liquid that passes through the filter paper is called the filtrate. In this case, water is the filtrate.


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Mandatory Experiment *To separate sodium chloride from a solution of sodium chloride in water. Apparatus required: evaporating basin, tripod, wire gauze, beaker, Bunsen burner, salt solution Method

1. Pour salt solution into evaporating basin. Put evaporating basin on tripod

2. Heat evaporating basin gently until most of water is driven off 3. Place evaporating basin over beaker of boiling water. (Heating

with boiling water prevents the salt from crackling and spurting out of basin during final stages of evaporation)

4. Remove salt from evaporating basin and show to teacher.


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Mandatory Experiment * To purify rock salt (sand and salt) using filtration and evaporation Apparatus required: pestle and mortar, beaker, stirring rod, Bunsen burner, tripod, wire gauze, conical flask, evaporating basin, retort stand and clamp, rock salt Method

1. Crush rock salt with pestle and mortar 2. Put rock salt in beaker of warm water and stir to dissolve salt.

Add more water, if necessary, to dissolve all salt and continue heating

3. Turn off Bunsen burner and leave beaker stand until it cools. Filter the warm mixture into conical flask

4. Evaporate water from sodium chloride solution using the same method as from the previous experiment. Examine what is left in the evaporating basin.


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Mandatory Experiment *To obtain a sample of pure water from seawater. Apparatus required: beakers, two retort stands and clamps, tripod, wire gauze, Bunsen burner, conical flask, rubber tubing, Quickfit apparatus, Liebig condenser, thermometer, pear-shaped flask, receiver adaptor, seawater, anti-bumping granules Method

1. Pour seawater into distillation flask. Add anti-bumping granules to help liquid boil more smoothly. Set up apparatus.

2. Turn on water to Liebig condenser (to keep the inner tube cool).

3. Heat distillation flask gently. Note temperature stays at 100 degrees celcius while water distils over. Note that as steam passes through Liebig condenser it is being cooled and converted to liquid again. The pure liquid being collected in receiver is called ‘distilled water’.

4. Remove Bunsen burner when most of liquid has been boiled off.


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Mandatory Experiment *To separate the dyes in a sample of ink using chromatography. Apparatus required: gas jar, glass rod, dropper, strip of chromatography paper, scissors, paper clip, markers of various colours, water (if dye is water soluble) Method

1. Cut strip of chromatography paper long enough for beaker 2. Using pencil, draw line 3cm from end of paper to indicate

where the spot will be put. Using marker, put spot of ink on line. Using pencil, write colour of ink and solvent on top of the paper

3. Pour some solvent (water) into container to depth of 2cm and hang paper so that solvent level is below the ink mark

4. When solvent reaches top of paper, take out paper and allow to dry. Examine chromatogram and note colours of dyes that were in the ink

5. Repeat experiment using different colour ink


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Mandatory Experiment *To investigate the pH of a variety of materials Apparatus required: rack of test tubes, universal indicator paper 1-14 and various narrow-range indicator paper, hydrochloric acid, sodium hydroxide, vinegar, limewater, washing soda, tea, milk, baking powder, lemon juice, toothpaste, cola, ammonia solution, distilled water Method

1. Use wide-range universal indicator paper (1-14) to find approx. pH value of each solution. If the substance is a solid, dissolve it in water before you test it.

2. Choose suitable narrow-range paper and measure each pH value more accurately. This is done by matching the colour obtained against the colour chart that comes with the paper.

3. Summarise your results in form of number line. Show the pH of substance you have tested on number line.


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Mandatory Experiment *To investigate the percentage of oxygen in air (using night light) Apparatus required: basin, night-light, graduated cylinder, matches, water Method

1. Light a night light and float it on surface of water in basin 2. Put graduated cylinder over burning the night light burns. The

water rises up inside the graduated cylinder. The water is pushed up by pressure of atmosphere.

3. Allow apparatus to cool. Measure volume of gas left in graduated cylinder.

4. By subtraction, calculate percentage of oxygen in air Conclusion

Oxygen occupies approximately one fifth of air.


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A more accurate method of carrying out the experiment is shown here:

Mandatory Experiment *To measure the percentage of oxygen in air (using gas syringes) Apparatus required: two gas syringes, two syringe holders, two retort stands, silica glass tube and connectors, Bunsen burner, copper turnings Method

1. Set up apparatus shown in the diagram 2. Fill one syringe with 100cm3 of air. The other syringe should

read 0cm3. 3. Pass all the air from the left-hand syringe over the heated

copper into the right-hand syringe. It will be observed that brown copper begins to turn grey-black. This is because the copper is reacting is reacting with the oxygen in air to form copper oxide.

4. Push the air to and from several times over the copper so that all the oxygen in the air reacts with the copper.

5. Allow the apparatus to cool. Push all the gas into left-hand syringe and measure the volume of air in it.

6. The total volume of air in syringe has decreased. This decrease must be equal to the amount of oxygen in the air.

Results

Volume of air in syringe before heating = 100 cm3 Volume of gas left after heating and cooling = 21cm3

Conclusion

Percentage of oxygen in air is 21%.


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Mandatory Experiment *To show that carbon dioxide is present in air Limewater tests for the presence of carbon dioxide as it turns milky white when carbon dioxide is passed through. Apparatus required: gas-washing bottle, two-holed rubber stopper, glass tubing, vacuum pump, and limewater Method

1. Set up apparatus as shown in diagram. Take care to connect vacuum pump to shorter piece of glass tubing.

2. Turn on tap to operate vacuum pump. Allow air to be drawn

through limewater for half an hour. Result

Limewater turns milky.


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Conclusion This shows us that carbon dioxide is present in air.

Mandatory Experiment *To show that water vapour is present in air Apparatus required: boiling tube, retort stand, rubber stopper, beaker, salt, ice, cobalt chloride paper Method

1. Set up apparatus with test tube of salt and ice mix hanging from retort stand. Make sure outside of tube is dry before experiment.

2. Observe droplets of liquid condense on outside of tube. Collect this liquid and test with cobalt chloride paper. This is blue, but turns pink in presence of water.

Result

The liquid turns blue cobalt chloride paper pink. Conclusion

The liquid that condensed on the outside of tube is water. Therefore, water vapour is present in air.

Mandatory Experiment *(a) To prepare a sample of oxygen *(b) To examine the properties of oxygen Apparatus required: dropping funnel, Buchner flask, delivery tubing, trough, gas jars, gas jar covers, beehive shelf, wooden splints, deflagrating spoon, hydrogen peroxide, manganese dioxide, water, blue and red litmus paper, charcoal, limewater, magnesium ribbon (a) to prepare oxygen sample:


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Method 1. Set up apparatus as shown 2. Allow hydrogen peroxide from dropping funnel to fall on

manganese dioxide so that oxygen is produced quickly. The oxygen is collected in gas jar, which is filled with water and placed on top of beehive shelf.

3. Collect five gas jars of the gas

(b) To examine properties of oxygen Method

1. Litmus and oxygen: Note that the gas is colourless and odourless. Put pieces of moist red litmus paper and blue litmus paper into jar of gas. Note that there is no colour change, so oxygen is a neutral gas.

2. Wooden splint and oxygen: Light wooden splint and place into jar of oxygen. Note how it burns more vigorously. Take out burning splint and shake so it is just a glow. Put glowing splint back into jar and notice how is bursts into flames gain. Oxygen rekindles a glowing splint.

3. Carbon and Oxygen: Heat some carbon (charcoal) on deflagrating spoon. When it is glowing, put it in jar of oxygen. The carbon continues to burn brightly, as this reaction is occurring – carbon +oxygen = carbon dioxide. Add limewater to the jar and notice how it turns milky white, showing carbon


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dioxide is now present, as it was formed when carbon was burned in oxygen.

4. Carbon dioxide and water: Burn more carbon in another jar of oxygen. Add water and blue litmus paper. Shake gas jar and notice how blue litmus paper turns red. This shows how carbon dioxide dissolves in water to form an acidic substance. This acidic substance is called carbonic acid.

5. Magnesium and oxygen: Burn magnesium metal in air, note how easily it burns with bright flame. Now burn it in jar of oxygen. Note how it burns a lot more vigorously in oxygen now. When magnesium stops burning, note the white powder formed in the gas jar. This is called magnesium oxide.

6. Magnesium oxide and water: Add water and litmus paper to gas jar of magnesium oxide. Note that the red colour of litmus paper turns blue. This shows a base has been formed. This base is magnesium hydroxide.

Mandatory Experiment *(a) To prepare sample of carbon dioxide *(b) to examine properties of carbon dioxide Apparatus required: dropping funnel, Buchner flask, delivery tubing, gas jars, gas jar covers, cardboard, test tube rack, test tubes, tapers, hydrochloric acid, limewater, marble chips, litmus paper (a) To prepare sample of carbon dioxide: Method

1. Set up apparatus as shown in diagram 2. Allow dilute hydrochloric acid fall on marble chips and note the

‘fizzing’ begins as soon as acid and marble come in contact 3. Add hydrochloric acid from time to time to keep reaction going 4. Collect three jars of gas, check each gas jar is full by lowering

lighted taper into it. If jar is full, taper will be extinguished at mouth.


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(b) To examine properties of carbon dioxide: Method

1. Note that carbon dioxide is colourless, odourless, tasteless gas

2. Put lighted taper in jar of the gas, note that it goes out. We conclude that it does not support combustion.

3. The characteristic for presence of carbon dioxide is that it

turns limewater milky. Bubble carbon dioxide through test tube of limewater and notice how it turns milky. The milkiness is caused by formation of chalk. The chemical name for chalk or limestone is calcium carbonate. This does not dissolve in water. The following is the reaction that occurs: limewater (calcium hydroxide) + carbon dioxide Chalk + water Ca(OH)2 + CO2 CaCO3 + H2O

4. Carbon dioxide is more dense than air. Pour carbon dioxide

from one gas jar into another. Test each gas jar for presence of carbon dioxide using limewater- limewater turn milky, so carbon dioxide is denser than air.

5. Carbon dioxide dissolves slightly in water to form an acidic

solution. Bubble it through water and test with litmus paper. The litmus turns red, showing the substance formed is an acid. The acid formed is called carbonic acid.


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Mandatory Experiment *To show presence of dissolved solids in sample of water Apparatus required: clock glass, Pyrex beaker, hot plate, tongs, water Method

1. Set up apparatus – Pyrex beaker with boiling water on hot plate, clock glass on the beaker with he tap water in it.

2. Bring the water in beaker to boiling point. Note steam produced, evaporates tap water from clock glass.

3. Turn off heat when all water in clock glass evaporated. 4. Using tongs, remove clock glass from beaker.

Result

Solid material left on clock glass Conclusion

Material must have been dissolved in the tap water. In many cases, these dissolved substances add a refreshing taste to the water.

Mandatory Experiment *To test samples of water for hardness Apparatus required: rack of test tubes, soap flakes, water samples (rain water, tap water, seawater, distilled water, hard water) In this experiment, the hardness of water samples is compared. We add soap flakes to water, small amount at a time until water gives a lather. The harder the water, the more soap flakes are required to give a permanent lather. Method

1. Add same amount of water from each samples to test tubes. 2. Add soap flake to each test tube.


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3. Put thumb over test tube and shake each test tube for a few seconds. Put each tube back and wait 20 seconds. If a lather remains after this time, we say one soap flake was required.

4. If lather does not remain, add more soap flakes and shake agin, wait 20 seconds.

5. Continue this way and record number of soap flakes required to produce a permanent lather.

Result

Each water sample requires different number of soap flakes to form a permanent lather.

Conclusion

The water sample that needs most soap flakes is the hardest. The water sample that needs least soap flakes is the softest.

Mandatory Experiment *To titrate hydrochloric acid against sodium hydroxide and prepare a sample of sodium chloride Apparatus required: burette, conical flask, retort stand and clamp, pipette, pipette filler, white tile, funnel, wash bottle, dropper,


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evaporating dish, Bunsen burner, tripod, wire gauze, beakers, dilute hydrochloric acid, dilute sodium hydroxide, methyl orange indicator Hyrochloric acid + sodium hydroxide HCl + NaOH NaCl + H2O Method

1. Set up apparatus as shown in diagram 2. Add the hydrochloric acid from the pipette slowly into the

conical flask with sodium hydroxide. Once the indicator in the conical flask changes colour, stop the titration and note the volume of the acid added.

3. Repeat experiment without using the indicator 4. The sodium chloride solution is put into an evaporating basin

and then this is put under Bunsen burner. 5. It is evaporated almost to dryness. The solution is left to cool. 6. Crystals of sodium chloride are formed.

Result

White crystals of sodium chloride are formed Conclusion

Hydrochloric acid and sodium hydroxide react to form sodium chloride


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Mandatory Experiment *(a) To investigate the reaction between zinc and hydrochloric acid Zinc+ hydrochloric acid zinc chloride + hydrogen Zn + Hcl ZnCl2 + H2 Apparatus required: dropping funnel, Buchner flask, delivery tubing, trough, test tubes, stoppers, beehive shelf, tapes, hydrochloric acid, zinc granules, water Method

1. Set up apparatus with the acid in the dropping funnel and the zinc in the conical flask beneath it

2. Let the acid fall onto the zinc and let the gas go through the delivery tubing, into the beehive shelf and the test tube with water

3. Collect about six test tubes of the gas

*(b) To test for hydrogen Method

1. Note that the gas is colourless and odourless. Note that there is no colour change when moist litmus paper is placed in it, so it is a neutral gas


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2. Put a lighted taper in jar of the gas and watch how it burns with a loud pop. Hydrogen burns with a loud pop when mixed with air.

3. Put empty test tube over one with hydrogen. Use lighted taper to test the empty test tube for hydrogen presence. NB: hydrogen is less dense than air.

Mandatory Experiment *To demonstrate that oxygen and water are necessary for rusting. In this experiment, three nails are placed in different conditions

One nail in contact with air and water Second in contact with air only Third in contact with water only

Apparatus required: 3 test tubes, test tube rack, rubber stopper, 3 steel nails, calcium chloride, oil, water Method

1. Set up three test tubes as shown in diagram 2. Put nail in test tube 1, with air and water 3. Put nail in second test tube that contains calcium chloride

(absorbs water), Therefore, there is no water in air in this tube. The stopper prevents moisture entering

4. Put third nail in last tube with boiled water and cover the water with oil. This prevents air dissolving in water when water cools down.

5. Leave apparatus for few days Result

Only nail that rusts is nail in test tube 1. This is only nail in contact with oxygen and water

Conclusion

Oxygen and water are necessary for rusting


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Physics

Mandatory Experiment *(a) To find the density of regular solid Apparatus required: rectangular block of wood, balance, ruler Method

1. Put block on balance. Note mass of block. 2. Measure length, width and height of block with ruler. Multiply

each result by each other to find volume. 3. Divide volume into mass to find density.

*(b) To find density of irregular solid Apparatus required: irregular solid (stone), balance, overflow can, piece of thread, measuring cylinder Method

1. Find mass of stone by placing it on balance and note reading. 2. Find volume of stone. Using measuring cylinder, measure

volume of water the stone pushes out of overflow can when it is placed in.

3. Divide the volume into the mass.


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*(c) To find density of liquid Apparatus required: water, balance, burette Method

1. Find mass of an empty dry beaker on balance. 2. Using burette, transfer liquid into beaker and calculate mass of

both on balance 3. Then, subtract empty beaker result from beaker and liquid

result. 4. Divide the volume into mass to find density.

Mandatory Experiment * Investigating the relationship between the extension of a spiral spring and the force applied to it Apparatus required: retort stand, spiral spring with pointer attached, metre stick, weights hanger with many equal weights Method

1. Measure natural/unstretched length of spiral spring. This is given by position of pointer on scale (this length must be subtracted from all other lengths to calculate extension below).

2. Attach hanger of known weight, this stretches spring. Note new length of spring and calculate spring extension.

3. Add weight to hanger and calculate spring extension. 4. Keep adding more weights and calculating the extensions. 5. Record results in a table


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6. Draw graph of extension (vertical axis) against stretching force (horizontal axis).

Results and conclusions

The graph results in straight line going through (0,0). Thus, the extension is directly proportional to the force which caused it.

Mandatory Experiment *(a) To show chemical energy changing to electrical energy to heat energy Apparatus required: 6 V battery, beaker, coil of resistance wire, connecting wires, switch, thermometer, Method

1. Put resistance wire under cold water in beaker. 2. Connect resistance coil through switch and to battery. 3. Put thermometer in cold water and note temperature after few

minutes. 4. Close switch. Note temperature of water every two minutes.

Result Temperature of water rises as long as battery is supplying

energy.


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Conclusion

The chemical energy of battery was converted to electrical energy in circuit. The electrical energy in resistance coil was converted to heat. The heat caused the temperature of water to rise.

Diagram missing thermometer and switch*.

*(b) To show electrical energy changing to magnetic energy to kinetic energy Apparatus required: a long nail, length of insulated wire, power supply, paper clips Method

1. Wind insulated wire around nail. 2. Connect two ends of wire to power supply. 3. Place some paper clips under nail. 4. Switch on current, not what happens. 5. Switch off current, note what happens.

Conclusion

Electrical energy from power supply changes to magnetic energy in nail. This causes the paper clips to move towards nail (kinetic energy).


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*(c) To show light energy changing to electric energy to kinetic energy Apparatus required: solar cell, miniature electric motor, strong light source, connecting wires Method

1. Connect solar cell to miniature electric motor. 2. Put solar cell in path of strong sunlight. Note what happens. 3. Block light arriving to solar cell. Note what happens.

Conclusion

Light energy is converted into electrical energy by solar cell. Electrical energy is changed to kinetic energy when wheel of motor rotates.


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Mandatory Experiment (a) To show that a solid expands when heated and contracts when cooled Apparatus required: metal ball and ring apparatus, Bunsen burner, tongs Method

1. Set up apparatus as shown in diagram. Check that ball just fits through ring when cool.

2. Using tongs to hold chain, heat ball over Bunsen flame for few minutes.

3. Using tongs again, try pass ball through ring. 4. Allow ball to cool. 5. Check to see if ball will now pass through ring.

Result

At normal temperature, metal ball just passed through ring. When heated, ball did not fit through ring. When cooled, the ball passed through ring again.

Conclusion

Ball expanded when heated and contracted when cooled.

(b) To show that liquid expands when heated and contracts when cooled Apparatus required: round bottomed flask with stopper and narrow glass tube at top, water bath, Bunsen burner, tripod, wire gauze, water (with dye added) Method


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1. Fill flask and narrow glass tube with water to high level. Mark level with elastic band.

2. Heat flask in water bath for few minutes. 3. Note new level of liquid in tube. 4. Turn off Bunsen burner. Allow liquid to cool. Observe level of

liquid after several minutes.

Result When heated, level of liquid in glass tube went up. When heat

was removed, liquid level went back down. Conclusion

Liquids expand when heated and contract when cooled.

(c) To show that gas expands when heated and contracts when cooled Apparatus required: round bottomed flask with stopper and long narrow glass tube at top, retort stand, large beaker of water, hair dryer Method

1. Set up apparatus as shown in diagram. 2. Heat flask with hair dryer. 3. Note bubbles appear at end of glass tubing in large beaker. 4. Now, take away hair dryer. Allow flask to cool. Observe what

happens. Result

On heating, air in long glass tube expands. When air cools, water rises up through sloped glass tube.


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Conclusion

Gas (air) expanded when heated. When the air cools, it contracts.

Mandatory Experiment *To show the transfer of heat by conduction and to compare the conductivity of various substances Apparatus required: rods of various substances (metals, glass, wood, or plastic could be used), metal container with holes and stoppers for inserting rods, Vaseline/wax, small nails Method

1. Set up apparatus as shown in diagram. 2. Vaseline/wax is put at end of each rod. Attach small nail to

each rod using the Vaseline. 3. Pour boiling water into metal container, covering inside ends

of the rods. Result

Nails drop from rods when heat arrives. Different materials conduct at different rates. The rod that drops its nail first is best conductor. All the rods can then be put in order of conductivity as nails drop off.



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*To investigate conduction in water Apparatus required: boiling tube, wire gauze, metal tongs, Bunsen burner, water, ice Method

1. Trap lump of ice with wire gauze at bottom of boiling tube as shown in diagram.

2. Add tap water to boiling tube until it is two thirds full. 3. Hold boiling tube at angle with metal tongs. Heat water near

top of boiling tube until it begins to boil. Observe what happens to the ice.

Result

The water at top of boiling tube boils. The ice at bottom does not even melt.

Conclusion

Water is a poor conductor of heat. Heat is unable to pass from the top of water to ice at bottom.

Mandatory Experiment *To investigate convection in water Apparatus required: large glass beaker, forceps, tripod, glass tubing, potassium permanganate, water, candle Method

1. Set up apparatus as shown in diagram.


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2. Using forceps, drop crystal of potassium permanganate to corner of beaker above candle.

3. Heat beaker gently with candle, Bunsen burner. 4. Observe what happens.

Result

The crystal colours the water near it and ‘currents’ are seen spreading throughout the water.

Conclusion

The water molecules near crystal are first to receive heat. This causes them to expand. They become less dense than molecules around them. Thus, they float to the top. Their path is shown by purple dye. Their place is then taken by denser colder water. This, in turn, is heated. This process is continued until all of liquid is heated. The moving currents of water are referred to as convection currents.

Mandatory Experiment *To show transfer of heat by radiation and that a dull black surface radiates heat better than a bright shiny surface.


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Apparatus required: two cans of equal size (one polished, one black), two temperature sensors and data logging equipment, retort stand, hot water Method

1. Pour equal amounts of hot water into each can. 2. Put temperature sensor linked to data logging equipment into

each can. Make sure both cans are put on non-conducting surface

3. Allow hot water stand in each can, stirring water from time to time

4. Compare graphs of temperature dropping with time for each can.

Results and conclusion

The temperature falls faster in container with dark surface. Therefore, dark surface radiates heat better than bright surface.

Mandatory Experiment *To show that light travels in straight lines Apparatus required: light source (candle), three identical cards with small hole in middle of each, plasticine, length of string Method

1. Put three cards about 10cm apart in line in front of candle. Use plasticine to hold them to the bench.

2. Thread length of string through holes. Pull string tight. This makes sure thee holes in cards are in straight line.

3. The light from candle should now be visible through holes. 4. Move one of the cards slightly to one side. Observe the result.

Result

The light cannot be seen when holes in the cards are out of line. Conclusion

The light from the candle travels in straight lines.


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(a) To investigate the reflection of light by plane mirrors, and illustrate this using a ray diagram Apparatus required: ray box with single slit, power supply, smooth plane mirror, white paper, pencil Method

1. Set up apparatus with ray box shining on mirror, place on white paper.

2. Darken the room. Shine ray of light from ray box at plane mirror.

3. Mark two Xs on path of ray going from ray box to mirror. Do same for ray coming out of mirror.

4. Move ray box. Increase angle (A) but keep ray of light aimed at same point on mirror.

5. Repeat for different angles. Result

The light is reflected from mirror in straight lines. There is a regular pattern. When the angle A is increased on one side, the angle B increases on the other side in similar way.


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(b) To demonstrate and explain the operation of simple periscope Apparatus required: two plane mirrors, retort stand, large obstacle (block), object to view, protractor Method

1. Set up two plane mirrors on retort stand. Put top mirror vertically above lower mirror. Tilt top mirror downwards at angle of 45 degrees Celsius to the horizontal. Tilt lower mirror upwards at angle of 45 degrees Celsius to horizontal.

2. Keep eye level with lower mirror. You should be able to see the image of the object on top of the block.

Explanation

The top mirror reflects the light from the object. It changes or deviates its path by 90 degrees Celsius. The bottom mirror also changes the path of the light through 90 degrees Celsius by reflection. Thus, you can see the object on top of the block.


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*To plot magnetic field of bar magnet using iron filings Apparatus required: bar magnet, iron filings, card Method

1. Put bar magnet on bench. Put card on top of it. Draw the outline of position of magnet on card.

2. Sprinkle iron filings evenly all over card. 3. Tap paper gently with fingers.

Result

The iron filings are influenced by strong magnetic forces from poles of bar magnet beneath. They are forced to point themselves along direction of magnetic field. Thus, they show the magnetic field around the bar magnet. Magnetic field lines always go from north pole to south pole.


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Mandatory Experiment *To test if a substance is a conductor or an insulator Apparatus required: 6 V battery, 6 V bulb, conducting wires, two crocodile clips, items to be tested (copper wire, candle, key, coins, plastic bottle, nail, comb, ruler, compass, paper clip, fruit, cotton wool etc.) Method

1. Make list of all materials you are going to test. Divide them into two columns, predicting whether they are conductors or insulators.

2. Set up circuit. At beginning there is gap between crocodile clips. The bulb does not light. The circuit is not complete yet.

3. Now, bridge the gap with each item you are testing, by inserting them between the clips. Note the result each time.

Result

The materials that cause the bulb to light brightly, like copper, steel and most metals, are good conductors.

Other materials, like plastic, paper etc., are insulators. Charge cannot travel through these materials. Thus, the light does not come on.


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(a) To measure the resistance of a coil (or resistor) Apparatus required: ohmmeter, coil (resistor), test leads and connecting wires Method

1. Set the multimeter to act as an ohmmeter by changing the dial to lowest resistance setting. Switch it on.

2. Connect test leads to each end of resistor. Note reading on ohmmeter.

Result

The reading on ohmmeter is resistance of coil. (b) To measure potential difference (voltage) and current and establish a relationship between potential difference, current and resistance Apparatus required: low voltage power supply, ammeter, voltmeter, switch, coil in beaker of water ( same coil as used above), connecting wires Method

1. Use connecting wires to connect up circuit. 2. Switch on power supply at lowest setting. Close switch. Current

will flow. 3. Note reading on voltmeter and ammeter. 4. Change to next setting on power supply. Take readings of

voltage and current again. Repeat process for several other settings.

5. Plot graph of voltage (vertical axis) against current (horizontal axis).

6. Divide each voltage by its corresponding current, 7. Find average of these results. Compare this average result with

resistance of same coil. Results and conclusion

The voltage across resistor is given by voltmeter reading.


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The reading on ammeter is the current in circuit. A straight-line graph going through origin shows that current is

proportional to voltage. This means that the current increases directly with the voltage.

The resistance of a resistor can be found by dividing potential difference across it by current passing through it.

The resistance of coil can be found by finding slope of graph of potential difference plotted against current.

mandatory experiments science notes jc-learn jc …...1. use forceps to take small piece of inner...

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