year3

Primary Science Lessons Year 3
Updated: 2008-04-31
Please send comments to: J.Elfick@uq.edu.au
Suggested answers to the teacher's questions are shown within [square brackets].

Animals	Ant life cycle	Mosquito life cycle	Butterfly life cycle	Cockroach, grasshopper	Plants and animal uses	Care of cats
Energy	Burn with a magnifier	Make water waves	Mix colours	Make rainbow colours	Spin a colour disk	String telephone
Human body	Describe our bones	Feel our bones	Record our heights	Move our arms	Make a plumb bob	Volume of our fist
Measuring	Single pan / simple balance	Balloon-powered rocket	Trundle wheel	Throw up and fall down	Volume of a liquid	Air temperature
Plants	Parts of a plant	Kinds of leaves	Describe leaves	Stems and roots	Seed and fruit	Make plant dyes
Rocks and soils	Plant foods in the soil	Soil animals	Soil water	Soil air	Soil contents	Waterlogged soil
Substances	Air takes up space	Float a hair pin	Convection heat snake	Paper aircraft	Air and water change places	Things that burn

Table of contents
3.1 Ant life cycle 1
3.1.1 Ant life cycle 2
3.2 Mosquito life cycle
3.3 Butterfly life cycle
3.4 Cockroach, grasshopper
3.5 Plant and animal uses
3.6 Care of cats
3.7 Burn with a magnifier
3.8 Make water waves
3.9 Mix colours
3.10 Make rainbow colours
3.11 Spin a colour disk
3.12 String telephone
3.13 Describe our bones
3.14 Feel our bones
3.15 Record our heights
3.16 Move our arms
3.17 Make a plumb bob
3.18 Volume of our fist
3.19 Single pan balance / simple balance
3.20 Balloon-powered rocket
3.21 Trundle wheel
3.22 Throw up and fall down
3.23 Volume of a liquid
3.25 Parts of a plant
3.26 Different leaves
3.27 Describe leaves
3.28 Stems and roots
3.29 Seeds and fruit
3.30 Make plant dyes
3.31 Plant foods in the soil
3.32 Soil animals
3.33 Soil water
3.34 Soil air
3.35 Soil contents
3.36 Waterlogged soil
3.37 Air takes up space
3.39 Convection heat snake
3.40 Paper aircraft
3.41 Air / water change places
3.42 Things that burn

3.1. Ant life cycle 1
See diagram 9.34.2: Ants | See diagram 9.34.1: Ant observation nest | See diagram 9.29: "Ant sucker"
Be able to describe the individual behaviour and social behaviour of an ant colony.
Use a large jar with tight screw top, a suitable ant's nest, magnifier.
Take the children to an ant nest. Dig up some of it and put the ants in a glass jar with a tight screw top. Put some leaves and bread in the jar. Let the children watch the ants in the jar for a few hours each day. What do the ants do? [Build their nest again.] Catch some ants and put them in methylated spirit. Let the children look at them with a magnifier. Note how many parts of the body. [3.] Note how many legs. [6.] Where are the legs attached? [At the middle part.]
Draw an ant. Label the parts. Note how many eyes and antennas.
Extra Activity: Are all the ants the same? Do any ants have wings? Draw the different kinds of ants.

3.1.1 Ant life cycle 2
Be able to identify the different stages in the life cycle of ants.
In this lesson teach the children to recognize the different stages in the ant life cycle by showing the children specimens from a nearby ant's nest. Use a suitable ant's nest, methylated spirit, small jars, magnifier. Make sure that the ants will not bite the children. You may need an ant sucker.
1. Open an ant's nest and collect the different stages of the life cycle. Where are the workers? [Everywhere, usually outside looking for food.] Where is the queen? [Find the queens deep inside the nest.] Where are the egg, larvae (grubs) and pupae? [In different parts of the nest.] Where are the males? [The males are hard to find because they die after the marriage flight.]
2. Draw some rooms and galleries of the nest. Can you see workers carrying eggs to safety when you broke open the nest? Take the specimens back to the classroom. Let the children look at them with a magnifier. Draw the ant life cycle on the chalk board. Ask the children why is it called a life cycle.
Extra Activity: Make a collection of ants preserved in methylated spirits. Complete the diagram starting from the eggs.

3.2. Mosquito life cycle
See diagram 9.8: Life cycle of mosquito
Be able to identify the different stages in the life cycle of the mosquito.
Use Stages of a mosquito life cycle as class specimens (live eggs, pupae, larvae and adults) jars and magnifiers.
1. The children can recognize stages in the mosquito life cycle because these insects can carry disease such as malaria fever, dengue fever, encephalitis, Ross River virus. Mosquitoes may also carry heartworm that is fatal to cats and dogs.
Male adults have feathery antennae. They do not bite people. Female adults do bite people to get a drink of blood. They live for about three weeks.
2. Show the children examples of eggs, pupa, larva and adult. The eggs are laid on the water at night as single floating eggs or stuck together to form rafts. a raft. The larva is the stage when you can most easily control the mosquito because it has to live in water for a long time. The larva has a breathing tube, siphon, that hangs down from the water surface, kept there by surface tension. However, Anopheles has a short siphon so the larva hangs horizontally, parallel to the water surface. Draining the water or adding insecticide to the water to kill the larvae can control mosquitoes. The pupa is unusual because it can wriggle. It does not feed and breathes air through two trumpet-shaped tubes. The mosquito life cycle lasts about seven days.
3. Show the children diagrams of the Anopheles mosquito that carries malaria fever.
Extra Activity: How can you can help to control mosquitoes near your home?
Remove water containers, e.g. buckets, discarded containers, roof gutters, pot plant trays. Cover entry spaces to rainwater tanks with fine wire mesh. Put fish that eat mosquito larvae in ponds, e.g. Gambusia or a local species if Gambusia is not allowed in your area.
If mosquitoes are common in your are do not go outdoor at dawn or dusk when mosquitoes are most active. If you must go outside, wear a long-sleeved shirt, long pants and use an insect repellent.
Encourage the children to collect stages of the life cycle of the mosquito found near their homes.
The most important species in Australia are as follows:
Culex annulirostris is mainly in the south-east. Ochlerotatus (Aedes) vigilax, the salt marsh mosquito, is mainly in the northern coastal areas. Ochlerotatus (Aedes) camptorhynchus is mainly in southern coastal areas. Culex molestus is in southern areas and it bites indoors at night. Aedes aegypti is in northern Queensland. Most Australian species may carry viruses but Aedes aegypti may carry dengue fever, break bone fever. The haemorrhagic form of dengue fever may be fatal. Non-biting midges look like mosquitoes but when they land on something they raise their front legs. Mosquitoes raise their back legs.

3.3. Butterfly life cycle
See diagram 9.7: Life Cycle of a Butterfly
Be able to describe the different stages in the life cycle of a butterfly.
Collect butterflies, eggs, larvae and pupae.
1. Show the examples of the stages in the life cycle of a butterfly. Identify the different parts of the larva (caterpillar) and adult: head, thorax, abdomen, antenna, mouth, eyes, legs, pro-legs, anus. Which adult butterflies are male or female. Why it is called a life cycle?
2. Questions about the adult butterfly: How many parts in its body? [3, head, thorax, and abdomen.] How many legs? [6.] How many wings? [4, two pairs How many eyes? [2 How many things on its head? [2, antennas. What is its colour? [Yellow etc. Does it have a tongue? [Yes, a rolled tongue that they can unroll to lick honey.]
Extra Activity: Keep some butterflies in a jar to try to see all stages in the life cycle. Draw the life cycle of the butterfly.

3.4. Cockroach, grasshopper
See diagram 9.9.1: Cockroach | See diagram 9.9.2: Grasshopper
Be able to make a model of an insect and name its parts.
Use a completed model insect: Plasticine or clay, dead insects (one for each child) magnifiers, little sticks or tough grass stalks (for legs and feelers) pieces of paper (for wings) small stones or seeds (for eyes).
1. Show the children your model insect explaining how you made it. Look carefully at their insects, the three main body parts, the six legs, the feelers, eyes, wings (if any.) Make a model of their insect from the Plasticine then use the sticks to put the legs and feelers in afterwards. Little stones or seeds can be used for the eyes and paper or leaves for the wings.
2. Compare their models with those of other groups. Name your insect models. Which group has the best model? How many parts of the body are there? [3.] How many eyes? [2.] How many antennas? [2.] How many legs on the middle part of the body? [6.] How many wings on the middle part of the body? [4.]
Sentence completion: The body of an insect has [3] parts. The first part, the head has two [eyes] two [antennas] and one [mouth]. The second part has six [legs] and sometimes four [wings]. What is the name of the model insect?
Extra Activity: Make a model insect of a butterfly or a grasshopper.

3.5. Plant and animal uses
Can explain how you use plants and animals to satisfy your basic needs? Background Information: your basic needs are food and water, clothing and shelter. In this lesson children will learn to appreciate how you use plants and animals to satisfy your needs. Food includes energy food, growth food, and healthy or protective food. Also it includes special foods for babies, for special ceremonies such as marriage and food that can be stored such as seeds and nuts. Clothing includes things to cover and protect your bodies. Shelter includes houses, fences, windbreaks and shade. This lesson can be taught in two ways and you can use both: 1.1 Which plants and animals are used to satisfy these needs? 1.2 List the parts of plants and animals and ask how they are used to satisfy your needs. Bring some examples to the classroom.
1. Explain your need for food, clothing and shelter. Ask the children to tell you examples of how these needs are satisfied by plants animals in their homes. Where does your food come from Where does your clothing come from Where does your shelter come from?
2. List parts of plants and tell the children how they satisfy your needs for 1. food 2. clothing 3. shelter
Extra Activity: List the plants and animals you use which are 1. grown locally 2. imported. Sentence completion: You use plants and animals to [satisfy] your need for [food] [clothing] and [shelter].

3.6. Care of cats
See diagram 9.309: Care of cats
Be able to care for a pet cat.
You will need a pet cat or kitten to the classroom. Cats are good pets because they are friendly animals and they kill mice and rats. However, they also kill native birds, so cats should be cared for and not allowed to go wild in the bush. Cats should be fed food scraps and have clean water. They should have a dry place to sleep and be allowed to wander about at night.
1. Show the cat to the children. Look at the cat carefully. What can they see? [The cat has a round head, short neck, narrow body, long flexible tail, covered with hair, narrow nostrils, big eyes, eye lashes, long whiskers, large external ears that can turn to catch sound, has canine teeth, 4-5 pairs of teats in female, hair falls out and is replaced, when angry the hair stands on end.]
2. Pick up the cat by the back of its neck. Look at the feet of the cat, what can you see? [There are the pads on the foot and on the toes. It has claws that can be pulled in.] Why can it pull in its claws? [It pulls in its claws to walk and not wear out the claws.]
3. Look at the cat walking. Can it walk in a straight line? [Yes, it can walk side to side in a straight line.]
4. Stroke the cat to make it purr. Can they make the same purring sound?
Extra Activity: Look at the eyes of the cat at different times of day and night. Can you tell the time by their eyes during the day? [The pupils of the cats' eyes are large at night and become a slit in the day.] Do cats eyes shine in the dark? [Cats' eyes reflect light but they do not shine by themselves.]

3.7. Burn with a magnifier
See diagram 4.3.7: Burn with a magnifier
Be able to : 1. use a magnifier to make things look bigger 2. burn things with the rays of the sun.
Use a magnifier and paper. You should try out this lesson before the children do it. You may have to do method 3. outside.
1. Draw a (T) on the back of your hand. Then look at the T with the lens close to the hand, then move the lens away. What happens? [The T gets bigger.] Then what happens? [The T disappears.] Then what happens? [The T appears upside down.]
2. Notice the distance from the T on your hand to the lens when the T disappears.
3. Let the sunlight pass through the glass to the back of your hand. can you see a bright spot? [Yes.] Do your hands feel hot? [Yes.] Move the lens up and down until your hands feel very hot. When does it feel hottest? [When the bright spot is smallest.] Notice the distance between the hand and the lens when the hand feels hottest. [It is about the same distance as when the T changed upside down.]
Extra Activity: Let the children use the lens to burn paper. The paper should be placed where the hand was before and left for sometime. Warning: Do not let the children look at the sun through a lens. Sentence completion: A magnifier brings together sunlight to make a [bright spot] and a [hot spot] on the hand.

3.8. Make water waves
See diagram 25.3.1.3: Make water waves
Be able to describe the movement and shape of waves in water.
Use a large flat container or a large plate, a sunny day, a dropper or outer case of a ball point pen, flat sticks or rulers. Children can observe that when the surface of water is disturbed by vertical movement, a wave moves horizontally away from the place of disturbance, but the water itself moves up and down only.
1. Put some water in the flat container in the sun. Let one drop of water fall into the centre. What do you see? [A circle getting bigger and bigger.] Tell one child to move the finger up and down just touching the surface of the water. What do you see? [The circles become bigger and bigger.] The circles are waves.
2. Let two drops of water fall into the container at the same time. What do you see? [The two circles of waves cross over each other.]
3. Hold a straight stick or ruler parallel to the surface of the water so that it just touches it. Move the stick up and down. What do you see? [Straight waves moving away from the stick.] Hold two sticks at an angle parallel to the surface of the water, move them up and down. What do you see? [The straight waves cross each other over.]
4. In which direction did you move the finger and the stick? [Up and down.] In which direction did the waves move? [Outwards, along the surface of the water.]
Extra Activity: Sprinkle some small sticks or leaves on the water. Then throw in a stone. Which way did the stone move? [Down.] Which way did the sticks and leaves move? [Up and down.]

3.9. Mix colours
Be able to describe colours and mixtures.
Use 1.1 examples of the different colours to show the children violet, indigo, blue, green, yellow, orange, red, 1.2 coloured paints or pencils or inks or chalks, 1.3. an old ball point pen, 1.4. small jars.
1. Describe 1.1 the colours of familiar things, cloud, sky, grass, hibiscus flower, birds, pollen, 1.2 things that can have different colours, hair, clothes, flowers, pencils (some hair is black, some is brown.) 1.3 things that change in colour, sky during the day, clouds on fine day and rainy day, ripening fruit 1.4 colours that you like and colours that you dislike: Green makes me calm, Red makes me angry 1.5 ask children to describe colours as follows: As green as [grass] as red as [blood] as blue as [sky] as white as [a sheet] as black as [night].
2. Give each group a small jar of water. Drop in some ink. Describe what happens to the ink: 1. if you do not stir it 2. if you stir it.
3. Give the children different colours. Let the children mix the colours two at a time. What is the new colour? Then mix all the colours together. What is the new colour? [Black.]
Extra Activity: Break open an old ball point pen. Get some colour out with a pin and put it in the water. What do you see?

3.10. Make rainbow colours
See diagram 27.1.80: Make rainbow colours
Be able to 1. make a rainbow form 2. see the seven colours of the spectrum.
Use a white dish, mirror and water. Light from the sun, and stars is called natural light. This light is said to be white in colour. In fact it is a mixture of seven different colours. These colours are the same as you see in a rainbow. The seven colours are red, orange, yellow, green, blue, indigo and violet.
1. Who has seen a rainbow? What does the rainbow look like? What are the colours? When do you usually see rainbows? [When the sun shines while it is raining.]
2. Fill a dish with water, hold a mirror sloping into the water then slowly move the mirror from side to side and up and down until you get a rainbow on the wall or ceiling. Keep the water as still as possible. Tell each child to have a turn at making a rainbow.
3. Look carefully at the colours, count and name the colours, write the names of the colours, say these names you have written. How many colours are there in a rainbow? [Seven.] Name these colours. [red, orange, yellow, green, blue, indigo, violet.] Where do these colours come from? [The sunlight.]
Extra Activity: If you have a garden hose, take the class outside, stand with your back to the sun and squirt a fine spray of water from the hose into the sky. A rainbow should be formed in the spray of water. Sentence completion: A rainbow is seen when [white] light from the sun divides into its [7] colours.

3.11. Spin a colour disk
Be able to discover what colour you see when you spin a colour disc. Use white cardboard, a pin, scissors, paints or coloured pencils: indigo, blue, green, yellow, orange, red. This demonstration is to show that when all the different colours are added you from white light. White light contains all the different colours. Black contains no colours.
1. Show the children how to draw a circle on the cardboard, cut out the circle, divide the circle into seven equal segments, then colour each segment a different colour.
2. Show the children how to push a pin through the centre of the circle. Tell the children to spin the colour disc. What do you see? [The disc appears white.] When the disc slows then stops, what do you see? [The colours appear again.]
3. When you spin the disc your eye sees the colours if you are added. Ask the children: What does that tell you about white light? [White light is made of the different colours added together.]
Extra Activity: You need blue, green and red cellophane or glass. Hold the three colours up to the sunlight so that you overlap. Blue over green gives purple. Blue over green gives blue green. Green over red gives yellow, brown. Blue over red gives purple. Blue over green over red gives black. All the colour has been taken out of the sunlight. Sentence completion: The different colours are [violet, indigo, blue, green, yellow, orange, red]. When you spin the colours together they form [white].

3.12. String telephone
See diagram 4.97: String telephone | See also 26.4.3: Sound travels along a string, string telephone
Be able to explain that sound can travel to and from solids through a tight string.
Use Two cans, string, match boxes, two match sticks.
Telephones are important modern communication instruments. They transmit sound through solids.
1. Press one finger against your throat and sing "ah!". Tell the children to tap on the desk and then press one ear down on the desk and keep tapping. What you can hear? The sound is louder which shows that sound travels best in solids.
2. Show the children the string telephone. Let one child talk quietly into one tin and another children hold the other tin close to the ear. The string should be tight. Let the string loosen by bringing the cans close together. Can they still hear the other child talking? [No.]
3. If sound travels best in air or in solids? [Solids.] How do you know this is true? Draw and label the string telephone.
Extra Activity: About sound under water. Hit two stones together above water then under water. Can you hear the two stones hitting when your ears are under water? [Yes, sound travels best in solids, then liquids, then air.]

3.13. Describe our bones
See diagram 9.230: Skeleton
Be able to examine bones and describe their functions.
Collect different kinds of animal bones, skull bones, backbones, ribs, shoulder bones, hip bones, arm and leg bones.
1. Give each group a collection of bones. Divide the bones into different shapes. Where are the following bones? - skull and jaw bones, backbones, shoulder and hip bones, ribs, arm and leg bones?
2. What are the functions of these bones? The skull protects the brain. The jaws moves the mouth and the teeth are attached to them. Backbones join to form the spine that connects all the bones. The shoulder and hip bones connect arms and legs to the spine. The ribs protect the lungs and heart, and allow the chest to get bigger and smaller. The arm and leg bones allow movement of arms and legs.
3. Draw and label some of these bones.
Extra Activity: How is a young bone different from an old bone? [The young bone is softer and contains soft material that makes blood, old bones are strong and may contain fat.]

3.14. Feel our bones
See diagram 9.230: Skeleton
Be able to observe types of joints and explain how you work.
Use bones, joints and charts showing bones and joints.
1. Where a bone joins another bone is called a joint. There are different kinds of joints: 1. Hinge joints are like a door, e.g. the knee, the movement is only forwards and backwards. 2. Ball joints, e.g. the shoulder, allows movement in a circle, you can swing their arm in a circle. 3. Pivot joints, e.g. the forearm, turns so you can turn a handle of a door 4. Fixed joints, joints of the bones in the skull do not move but you allow growth, e.g. a very young baby has a hole in the skull where the bones have not joined.
2. Show me the different kinds of joints in your body.
[jaw (hinge)
elbow (hinge and pivot)
finger (hinge)
foot (pivot)
upper leg (ball)
backbone (pivot)
neck (pivot and hinge)]
Extra Activity: Show the children a diagram of a skeleton, point to the joints and tell the children to say what type of joint it is.
1. Hinge joint, moves forwards and backwards
2. Ball joint, swings in a circle
3. Pivot joint, like turning a handle
4. Growth joint, allows plates of bones to get bigger.

3.15. Record our heights
Be able to 1. measure the height of all the children in the class 2. record the height in writing and as a bar graph.
Use ruler, book, pencil or chalk, metre stick or tape measure. Check the diagram to make sure that you know how to measure height consistently, book or ruler on head and at right angles to wall. Push down bushy hair. Push the back of the head, shoulders, buttocks and heels against the back of the wall. Look straight out. The measurer makes the mark on the wall. Use metre stick or tape measure with zero on the floor. Or carefully draw a metric scale or metre stick to wall. Measure in centimetres (cm) and to a nearest millimetre (mm), e.g. height of the child is 15
1. 7 cm. Draw a bar graph to nearest centimetres, e.g. 152 cm.
You should keep records of your height to see how fast you grow. Show the correct way to record height and how to record it in your book, Date, my height is 143. 6 cm. Draw a big scale on the chalk board and tell the children to read it. Divide class into pairs. Let the children measure each other and write their height in their books. Write the name of the child on the chalk board. Write their heights next to their names. Draw a bar graph of the heights in centimetres. Label each bar with a name.
Extra Activity: Measure the children again months later. Show the new heights as extensions of the bar. Sentence completion: Date. my height is [ m] this is equal to [ cm] or [ mm].

3.16. Move our arms
See diagram 9.232: Movement of the arm
Be able to display the action of muscles in the arms and legs.
Try out this lesson on yourself before teaching it. Remember that muscles work only by contraction, i.e. pulling, so for each muscle that bends a limb, another muscle can straighten it again. When a muscle contracts it changes in shape but it does not change in volume.
1. Touch the fleshy part of your upper arm. This fleshy part is called muscle, joints are moved by muscles.
2. Close one hand, and form a fist, then bend that arm at the elbow, while feeling the muscle of the upper arm with your other hand, to feel the change in shape of the muscle as the arm is raised and lowered. As the arm is raised, the muscle becomes short, fat and hard.
3. Lie on the ground on your backs and feel your stomach while raising your legs.
4. Explain to the children that muscles move bones by pulling on them and that when you pull something the muscles become short and fat.
5. Encourage the children to try many different movements, e.g. walking on their toes, lifting objects, press ups, standing on hands, knee bend and tell the children to feel and see their muscles and joints working.
Extra Activity: Keep a straight back then bend the knees until your hand touches the floor. Who can do the most knee bends Where do you feel the pain? Feel behind the legs above the knees, when you bend, when you straighten. Can you feel the muscle that straightens the legs?
Sentence completion: Arms and legs move because of pairs of [muscles]. One muscle [bends] the joint. The other muscle [straightens] the joint.

3.17 Make a plumb bob
See diagram 3.17: Plumb bob
Cut out a 15 cm X 15 cm square of stiff paper. Roll the paper into a cone about 15.5 cm long with a sharp point and about 3 cm in diameter at the open end. Use adhesive tape to secure the end flap of the paper. Fold down the triangle of paper projecting up from the rim of the cone. Hold the cone upside down an tap it down to produce an even edge around the opening. Apply adhesive tape over the opposite edges of the opening of the cone. Punch two holes through the adhesive tape and paper exactly opposite each other. Cut 5 cm of light string and pass it through the two holes to make a handle. Tie knots in the ends of the string outside the holes. Cut a piece of thread 25 cm long. Tie one end of the thread around the string handle as a loop and tie a loop in the other end of the thread so that it can fit around your finger. Put a marble or round lead sinker in the centre of the paper cone or fill it with sand. Put the loop around you finger and check whether parts of the room are vertical. The thread of the plumb bob shows the vertical direction. It is pointing towards the centre of the earth.

3.18. Volume of our fist
Be able to measure the volume of your fist.
In this lesson children can learn two ideas. They learn that the volume of an irregular object such as the fist is equal to how much water displaced by it. Also, they learn that when the fists opens or closes, the displaced volume of water remains the same. You will need a large glass container or tin that the children can safely put their hand in, and open and close the hand. Also, you will need a measuring jug to measure the volume of the fist. Try this experiment with your own hand before you do it. Make sure there are no air bubbles inside your fist.
1. Give out a container half full of water. Draw a line along the first line on the skin of the wrist. Put their elbow on the desk then look at the palm of their hand. What is above the line? [The hand.] What is below the line? [The wrist.] Curl the fingers and thumb together. What is above the line? [The fist.]
2. Mark the original level of water in the container as "A". Put the fist into the water up to the line on the wrist. What happens to the level of the water as the fist enters the water? [It rises.] Mark the new level of water in the container as "B". Take out the fist. What is the new level of water? ["A"] Pour water from the measuring jug until the level is at level "B". How much water poured out of the measuring jug = the volume of the fist (B - A).
3. Overflow
Fill the container with water right to the top. Be ready to catch any water spilled out and put it into the measuring jug. Very slowly put their fist into the water. Water spills over into the measuring jug. The volume of the water spilled over is equal to the volume of their fist. Is the volume of the fist the same as in 2? [Yes.]
4. Open the fingers, look at the open hand. Is the volume of the hand bigger or smaller then the volume of the fist? [You must do an experiment to answer this question.] How can you can test this? [Put the fist in water again.] Put the fist in water. What is the level of the water? [The container is full.] Open their hand under water. What happens to the water level? [No water spills over so the volume of the open hand = the volume of the fist.]
Extra Activity: How would you measure the volume of the middle part of your finger from A to B? [Dip the finger down to level B, then down to level A, volume of middle part is A, B.]

3.19. Single pan balance / simple balance
See diagram 4.12: Different balances
Be able to measure the weight of different objects using a single pan balance.
Use a large clock face scale balance, e.g. Salter 100 kg and / or a small spring balance, e.g. Ohaus, 250 g rope or string, a string bag or plastic bag, and things that can be weighed, e.g. stones, books, garden produce. You will need somewhere to hang the balances from, e.g. nails in the wall.
One group for each balance.
1. Show the children how to count around the scale of the clock face balance [10, 20, 30, 40 50, 60, 70, 80, 90, 100.] or show the children how to count along the scale of the small spring balance [0, 50, 100, 150, 200, 250.].
2. Tell the children to draw a balance scale in their books and label it. Note kg means kilogram and g means gram. Kilograms and grams are used to show how heavy something is.
3. Hang the balance from a nail in the wall then hang a string bag or plastic bag from the hook hanging below it. Move the pointer to zero by turning the adjustment knob. Add stones one at a time to the bag and note where the pointer moves. Take off the stones one at a time until the pointer returns to zero.
4. Draw the scales on the chalk board. Show the children how to count the main subdivisions.
5. Show the children how to read the pointer to the nearest subdivision.
6. Give the children different things to weigh.
Extra Activity: If you have both 100 kg and 250 g balances hook them together then pull outwards. What are the readings on the balances? [The same.] Weigh some sizeable objects using the balances. Sentence completion: You measure weight in [kilograms and grams]. You measure weight with a [balance].

3.20. Balloon-powered rocket
See diagram 4.103
1. Use adhesive plaster to paste several small iron rings to the side of a long shaped balloon. Use a straight slippery thin iron wire (if existing iron wire is not straight, you may step on it then rotate it several times so that it will became straight.) Insert the iron wire through the iron rings and fasten the iron wire to any two rings. 2. Put a small glass's end into the mouth of the balloon. Use white adhesive plaster air proof the connecting part of the glass and the balloon. Hang the glass to two rings on the iron wire with a piece of string. Make sure he glass parallel to the iron wire. Now this is a balloon driven "rocket". The end of the iron wire near the bottom of the balloon is the rocket head 3. Draw the balloon backward to the other end of the iron wire. Inflate the balloon then release it suddenly. Observe how far the "rocket" can go ahead. 4. Plot a graph using the times of blowing as x-axis and the distance of the "rocket" gone as y-axis. 5. Bend up the "rocket head" a bit then repeat the experiment.

3.21. Trundle wheel
See diagram 2.0.9: Trundle wheel distance
1. Be able to use a wheel to measure length.
Each child will make a toy with wheels. The wheels can be made by cutting slices of a banana stalk or using cotton reels, bottle tops, typewriter ribbon holders. Show how to make an axle. You will need a banana stalk, bottle tops, cotton reels and wire. Also, collect a motor car tyre, a rim and an iron hoop.
Individuals
1. Let each child make a wheeled toy. Let the children race along the floor. Who can make the best toy?
2. Make a mark on one wheel. What happens when the wheel turns? [The mark goes round.]
3. Move the toys a short distance. How often does the mark go round?
4. Move the toys a certain distance, e.g. the length of the classroom. Count the number of times the mark goes around.
5. Which wheels turn the most? [The smallest wheels. Which wheels go around the least? [The largest wheels.
Extra Activity: Put a mark on a car tyre or iron hoop. Bowl it around the classroom. How many times does it go around? Use this to measure the distance between two trees, e.g. the distance is that the tyre goes around 14 times.
2. Be able to measure distances along the ground using a trundle wheel.
Use a piece of plywood or metal sheet at least 32 x 32 cm in area, a stick and some wire. For part 5. a rope or string 7 metres long. The circumference of the wheel should be one metre.

3.22. Throw up and fall down
See diagram 14.2.2: Up and Down
Be able to measure the time taken for an object thrown up to fall down again.
Use a stop watch, second hand of a watch, stone or ball. You will need a watch with a second hand or stop watch or you can count constant time intervals: One and two and three and four and. Remember 60 seconds = one minute.
1. Timing a whistle
Let the children see the second hand of the watch. Tell one child start a continuous whistle when you drop your hand and to stop when you raise your hand. How long did the child whistle?
2. Timing a throw
Select two children who are good at throwing and catching a ball. Let the other children see the second hand of a watch. How many seconds between leaving the thrower's hand to reaching the catcher's hand?
3. Timing a falling object
Tell one child to pick up a stone or a ball and climb a tree. Let the other children see the second hand. How many seconds between leaving the climber's hand to hitting the ground? Repeat this many times, from the same height until you get the same result twice.
4. Problem: If you throw a ball or stone up, will it take longer to go up or to come down? [You must do an experiment to find the answer: Select a child who can throw very high. Measure 1. the time from thrower's hand to the highest point it reaches and 2. the time down from the highest point it reaches to level of thrower's hand.] Which is the longest 1. or (b)? [1. = (b).]

3.23. Volume of a liquid
See diagram: 2.1.6: Volume of a liquid
Be able to measure the volume of a given liquid using a graduated container. Use 1.1 a graduated container, e.g. graduated cylinder, measuring jug, rain gauge 1.2 bottles and jars of different sizes and shapes. Some useful measurements: 1,000 mL = one litre. A bottle top holds about 3 mL: a teaspoon holds about 4 mL, a dessertspoon that you use for eating holds about 7 mL, a teacup holds about 225 mL, a mug about 250 mL, a matchbox holds about 25 mL of sand.
1. Give each group some glass jars or bottles. Look carefully at the surface of the water, especially where it touches the glass. To draw the shape of the water surface, it is called a meniscus.
2. Draw water in a graduated cylinder on the chalk board. Remember that when you measure liquids: 2.1 The scale and container should be vertical (show this), 2.2 The eye should be in the same line as the flat water surface, 2.3 The volume is the nearest mark to the flat water surface.
3. Measure a volume of W, e.g. 200 mL. Pour it from one container to another. Does the water have the same height in the container? [No.] Does the water have the same shape in each container? [No.] Is the same amount of water in each container? [Yes, 200 mL.] Pour some water from the containers into a graduated cylinder. Can you read how much water? [Yes.]
Extra Activity: Use a graduated container to pour water into a plastic bottle. Make a mark on the bottle for each 100 mL. You now have a measuring bottle. Measure the volume of some bottles and jars by pouring from the plastic bottle. Sentence completion: You measure the volume of liquids in [litres and millilitres]. You measure volume using a [measuring cylinder or measuring jug].

3.24. Air temperature
See diagram 22.02: Thermometers
Be able to observe the difference in temperature in different places.
You will need a 0^oC to 100^oC thermometer and different places where differences in temperature can be seen. Do not let children hold the bulb of the temperature in the sun. The thermometer will keep absorbing heat energy, the mercury will continue to expand and will break the thermometer. Measure temperature differences at different places in the classroom, different depths in the soil, bare soil, soil under mulch, soil under shade, under different types of shade grass, coconut, banana, bush, in and out of water or mud, in a compost heap.
1. Each child must read the thermometer. Explain how to measure the temperature in different places. Write a list of places in their book.
2. Give each child a chance to read the thermometer in a different place and record in their book.
3. What differences did they notice, e.g. under different shades, in the soil, in the classroom, in water?
Extra Activity: How does temperature in soil change during the day? Does it change more, when deep in the soil or just under the surface?

3.25. Parts of a plant
See diagram 9.53: Parts of a plant
Be able to identify the parts of a flowering plant,
You will need small plants with flowers. You can tell the children to collect the plants before the lesson. Any plants can be used, but they must be complete plants. Do not use ferns because they are not flowering plants.
1. Show the class a complete plant and name its main parts, flowers, stems, leaves, roots etc. Which parts of the plant are usually green? [Leaves.] Which part of the plant grows under the ground? [Roots.] Which parts are often brightly coloured? [Flowers.] Which part of the plant has the leaves and flowers growing on it? [Stem.]
2. Go outside and find a small plant that has flower, stem, leaves and roots.
3. Dig the plants up carefully, do not break off the roots.
4. Break the plant up into its various parts. Can you name the parts? [Flowers, stems, leaves, roots.]
5. Count the number of different kinds of parts. How many leaves, flowers, stems, roots in one plant?
Extra Activity:
1. Nature walk: Tell the children to name the parts of different trees and small plants they can see during the nature walk. Flowering plants are made up of two parts. One part is usually found under the ground and is called the root system. The other part usually grows above the ground and is called the shoot system. The shoot system consists of the stem and its branches, the leaves, the flowers and the fruits containing the seeds.

3.26. Different leaves
See diagram 9.66.1: Different leaves
Be able to classify leaves in two ways: simple / compound and network / parallel veins.
Use simple leaves, e.g. Hibiscus, Euphorbia, Acanthus, Eucalyptus, breadfruit, five corner, guava, papaya, kumara, cassava, compound leaves, e.g. any of above: parallel veins, e.g. grass, coconuts, banana, rice, onion, bamboo, ginger.
1. What does classify mean? [It means to put things into classes.] In this lesson the children will learn how to classify leaves in two different ways. Give each group a mixture of simple and compound leaves. Classify the leaves into two classes and tell you the character of each class. Let the children discuss this. You should visit each group.
2. Draw the character of simple or compound leaf on the chalk board.
3. Mix the simple and compound leaves together again in one pile for each group. Add to each pile different leaves with parallel veins. Divide the pile into two classes. Let the children discuss this. Both simple and compound leaves have a network of veins. Other leaves are long and thus have parallel veins. Name some plants with simple leaves, compound leaves, leaf veins in a network, leaf veins parallel.
Extra Activity: Garden Walk, pick some leaves in the garden and classify them. If you scrape the leaves with your thumb nail and use a magnifier you can see the veins clearly. Sentence completion: You found ways to [classify] leaves. 3.1 Look at a whole leaf. The two classes are [simple leaves] and [compound leaves]. 3.2 Look at the veins in the leaves. The two classes are [network of veins] and [parallel veins].

3.27. Describe leaves
See diagram 9.66.2: Leaf collection
Be able to collect different shaped leaves and classify them.
You will need different shaped leaves.
1. Give each group a pile of leaves from different plants. Show that all leaves have three parts:
1. The largest part is thin and flat. [leaf blade]
2. The thin and round part is like a handle. [petiole]
3. The little knob at the end of the handle is where the leaf joins the stem. [leaf base]
2. Divide the leaves into piles:
Pile one contains hand-shaped leaves, e.g. chilli, hibiscus, taro.
Pile two contains long and thin shape leaves, e.g. mango, coconut leaflets.
Pile three contains dented shapes, e.g. passion fruit, snake gourd, papaya (pawpaw).
Pile four contains leaves divided into little leaves, e.g. Pueraria, cassava.
3. Look at the extra leaves. Which pile do they belong to?
4. Display different leaves on a wall board.
5. Trace the shape of different leaves on paper. Can you colour them?
Extra Activity: Leaf Press. Collect many sheets of newspaper, two pieces of wood as big as a newspaper page, four heavy stones. Go outside in groups of four and collect many different leaves from all kinds of plants. Return to the classroom and give each group two sheets of paper. Show how to arrange their leaves between the sheets of paper. Make a pile of all the collections, then place heavy stones on the top. Put the leaf collections in a safe place and let the children look at them after a week.

3.28. Stems and roots
See diagram 9.57.3: Different stems | See diagram 9.73.1: Types of roots
Be able to classify stems and roots according to their functions.
Collect samples of the following groups of plants, or prepare to take children to see them. 1.1 hibiscus, weeds, small woody plants, woody stems and tap roots, 1.2 beans and peas, soft stem and tap root grass, bamboo, corn, stem divided into sections and fibrous roots, 1.3 grass, bamboo, corn, stem divided into sections and fibrous roots, 1.4 pumpkin, melon, hollow stem and tap roots, 1.5 banana, no stem and fibrous roots, 1.6 sweet potato, yam, taro, swollen stem, g. cassava, carrot, radish, beetroot, swollen tap root
1. Give each group different plants. Look at the stems and the roots. Tell the children to divide the plants according to different kinds of stems and different kinds of roots. Show them plants with: 1.1 woody stems. They are hard to break. 1.2 soft stems. They are easy to bend. 1.3 stems divided into sections. The bumps on the grass stems. 1.4 hollow stems. They can look through the pumpkin stem. 1.5 no stem. The banana has a little stem under the ground but above the ground its stem is made of leaf bases. 1.6 swollen stem. The carrot is swollen with starch for food.
2. Show you a plant with a: 2.1 tap root. It is one big root and lots of smaller roots. 2.2 fibrous roots. It is lots of little roots. 2.3 swollen tap root. It is swollen with starch for food, e.g. cassava.
3. Cut open the stems and roots to see the parts inside. Can you see where the starch food is stored? [It is white, if you put some iodine solution on it turns blue.] Sentence completion: The two types of roots are [fibrous roots] and [tap roots].

3.29. Seeds and fruit
See diagram 9.113.2d: Bean seed | See diagram 9.100.4: Fruits
Be able to recognize different types of seeds and fruits.
Use different kinds of fruits and seeds. [A legume must be provided.] All flowering plant produce seeds inside a fruit that is sometimes called a pod or nut. Before fertilization of the flower the seeds were called ovules and the fruit was the ovary. Seeds contain growth food and some healthy food and energy food. The fruit protects the seeds. Some fruits have hard walls that break open to let seeds out when you are ready to grow. Other fruits have fleshy walls to attract birds and other animals to eat the fruit and seed. These fruits are good healthy food.
1. Show children the legume pod. Show the children the seeds inside the fruit. What are the names of seeds and fruit that you eat? Write a list on the chalk board.
3.

Name of plant	Corn	Coconut	Lime	Mango	Papaya	Tomato
Eat the fruit?	yes	inner wall	inner wall	inner wall	inner wall	yes
Eat the seed	yes	no	no	no	no	yes

[The corn (maize) seed is also a fruit.]
2. Some seeds and fruit cannot be eaten by us. Some have spines, some have parachutes. Can you name some of these seeds and fruit?
Extra Activity: Seed collection. Collect some dried fruits with seeds in them. Crush and rub the fruits to get the seed out. Clean the seed by picking off the outer shell.

3.30. Make plant dyes
Be able to make plant dyes and use them.
They will need a collection of plants to make the dyes, e.g.
Wild banana leaves, black
Banana leaves, yellow
Sweet potato leaves, green
Hibiscus leaves, red brown
Young coconut fruit, black
Sweet potato flowers, yellow
Bougainvillaea flowers red/purple
Tumeric root, yellow
Onion skin, yellow
Bamboo, green
Fern, brown
Lichens, orange/brown
Geranium flowers, red
Morning glory flowers, yellow
Background Information: A dye is the substance used to change the colour of something. Before the lesson tell the children to bring some parts of plants used for dyes. You will also need something to crush the plants, e.g. mortar and pestle, a tin that can be heated, cloth, and mordants if you want to do permanent dying.
Extra Activity.
1. Show the children the parts of the plants. Record the names and colours of each part.
2. Show the children how to crush the plants and squeeze out the juice. Note the colours of the juices. Are they the same as written on the chalk board?
3. Boil the juices, have they changed in colour
4. Put some dried material or dried grass in the dyes and let them dry.
5. Crush the plants in methylated spirit. Do they get the same colours?
6. Permanent dyeing. 6.1 Boil material for one hour in a mordant, e.g. three parts alum [Al₂(SO₄)₃.K₂(SO₄).24H₂O, potash alum] and one part cream of tartar (potassium hydrogen tartrate). 6.2 Squeeze out the mordant then boil material in the dye.

3.31. Plant foods in the soil
See diagram 6.65.1: Soil nutrient cycle | See also 6.9.14: Composting
Be able to explain that plant foods are in the soil.
This lesson is to teach children that plants can absorb something out of the soil that you use as plant food. In secondary school, children learn that plants manufacture food during photosynthesis using light, carbon dioxide, water and minerals from the soil. These minerals are usually called plant nutrients. The Term plant food is not used because plants make food. They do not suck up food from the soil. However in primary school you call minerals plant foods because this is easier for children to understand.
1. What did you eat today? [Food.] Where does food come from? [Animals and plants.] Where do animals get their food from? [They eat other animals or they eat plants.] Explain that all food comes from plants. Plants are food.
2. What plants need to grow Have you seen plants growing in the dark under a stone or under a house? [No.] Plants need sunlight to make food.
3. Why do you breathe? [You need air.] Can you stop breathing? [No.] Explain that plants also need air to grow.
4. Have you seen plants growing where there is no water? [No.] Plants need water to grow.
5. If plants can move around like animals. [No.] Why not? [They have roots in the soil.] Explain that the roots can take two things out of the soil:
5.1 They can take out water., 5.2 They can take out plant foods.
6. What are the four things plants need to grow? They need: 6.1 sunlight, 6.2 air, 6.3 water, 6.4 plant foods from the soil. Explain that if the same crops are grown in the soil year after year some plant foods will be used. If you grow different crops in the same soil or if you let the soil rest the plant foods will not all be used up.
Extra Activity: What happens if maize / yam / potato / bean is grown in the same soil year after year? [You get less yield.] Why is this? [The plant foods for the crops have been used up.] Ask some village people to explain what happens when you grow the same crops in the same ground year after year.
Sentence completion: Plants need four things to grow. They are: [sunlight] [air] [water] and [plant foods]. If the same plants are grown in the same soil year after year, the plant foods will be [used up] and you will get [less] plants or fruits.

3.32. Soil animals
See diagram 9.306: Soil animals
Be able to examine the different kinds of animals in the soil and litter.
Use glass jars with cover (lids) magnifiers and water. Litter is the fallen leaves and sticks on top of the soil. From deep in the forest get cups full of soil and get the litter above it. Some animals you can find in the soil:

worms	grubs	insects	spiders	millipedes
no legs	many legs	body in three parts, six legs	eight legs	many legs

1. Give each group some soil, some litter, a jar of water and a magnifier. Look for different animals and put them into the jar of water.
2. What are the names of the animals?
3. Which has more animals - the soil or the litter? [soil.]
4. Put the soil and litter in different water containers. Can you find more animals?
Extra Activity: Make a funnel from a piece of paper. Push it into a jar so that the narrow end does not touch the bottom of the jar. Put some leaf litter or soil in the funnel. Put an electric light globe over the wider end of the funnel. The next day lots of animals will be found in the jar.
Sentence completion: The animals you found in the soil / litter were: [worms, insects etc.].

3.33. Soil water
See diagram 6.10: Soil water
Be able to show that soils hold water. Use a place to dig in the garden, enough sand for each group, sheets of paper, clear container such as plastic bags or bottles, string or rubber bands for the plastic bags, lids for the bottles, water, garden soil, spades or digging sticks.
1. Take the children outside and give them some dry sand to play with. Wet the sand and feel it. What is the difference between dry and wet sand? - look, feel, move and make shapes. [Wet sand is darker, smoother, sticky and easier to make shapes with.]
2. Give out the materials and tell the children to dig a 15 cm hole in the garden. Let the children put the soil in their containers and close them. Leave containers on their sides in the sun while you do the next step.
3. Press a little soil between two sheets of paper. Look carefully at the outside of the paper and say what you see. [Water, the paper is wet.]
4. Look at their containers and compare them with other groups. Then open their containers and fell the inside surfaces. What you feel and see and where it comes from. [Water from the soil.] When a container of soil is left in the sun, what forms on the inside of the container? [Water.] Where does this water come from? [The soil.]
5. If soil is pressed between two sheets of paper, what happens to the paper? [It gets wet.] Does soil contain water? [Yes.] Sentence completion: Garden soil contains water. When you heat soil the water [is lost].
Extra Activity: Add water to some dry sand and wet it. Heat the wet sand on a tin lid. Note the water being driven off as steam. Show that after heating, the sand is dry again. Bury a piece of dry cloth in dry soil then dig it up a few days later and examine it. Heat some soil then hold a mirror over it. What do you see? [Water forms on the mirror, it came from the soil.]

3.34. Soil air
See diagram 6.8: Soil Air
Be able to show that the soil contains air.
Use soil, water, a small tin cup and a jar big enough to contain it. You can fill the tin with soil before the lesson by pressing it down slowly into the ground. Half fill the large jar with water. You can mark water on the side of the jar. Try this experiment before the lesson. Spilling water and soil over the floor is easy if you have not done it before.
1. How can you show that there is air in the soil? You have a small tin full of soil and a large jar containing water. Record how much water in the jar. [Level A below.] Put the small tin full of soil into the water open end down. What happens to the level of the water? [The level of water rises. Level B below.] Record the new level of water in the jar.
2. Keep the tin of soil under the water and turn it open end up. What do you see? [Bubbles rise. The water level drops to Level C below.] When the bubbles have stopped rising look at the level of water in the jar. What do you see? [The level has dropped.] Why did the level of water drop? [The air came out of the soil and the water took its place.] Is there air in the soil? [Yes.] How do you know? [You saw bubbles of air rise out of the soil.] What was the volume of the tin containing the soil? [Volume B minus Volume A.] How much air was in the tin of soil? [Volume B minus Volume C.]
3. Plant roots need the air in the soil so that they can breathe. If there is too much water in the soil most plants die because their roots do not have air to breathe.
Extra Activity: Do the experiment again with sandy soil and clay soil? Which has more air? [Sandy soil.]

3.35. Soil contents
Be able to divide a sample of soil into different parts to see what it is made of.
Spade, containers or paper, charts on soil. Before the lesson select a place in the garden where there is deep soil containing lots of organic matter.
1. Take the children outside to the garden. Give each group a space and a container or piece of newspaper. Dig up the soil, about 10 cm x 10 cm x 10 cm. Sort the soil into three parts 1. any living things (plant or animal parts) 2. any things that were once living but are now dead 3. any things that were never alive, place each part on a separate piece of paper.
2. Look carefully at what you have found, compare what you have found with what other groups have found, see which group can find the most things.
3. Make a table on the chalk board and ask each group to enter their group's findings in it. Ask one member of each group to tell the rest of the class about one thing the group has found in the soil, e.g. stones, moss, worms, leaves, bones, sand, fungi, ants, shells. Use these headings for the table: Living Plants Living Animals Dead plants Dead Animals Non-living things
Extra Activity: Different groups could dig up ground in different areas, e.g. near the classroom, food garden, flower garden, bush, playground. The children could then compare the different areas to see which contained the most living matter. Sentence completion: You divided the soil into three parts: [living things] [dead things] and [non-living things].

3.36. Waterlogged soil
Be able to examine the soil and find out if it is waterlogged. Determine how to drain a waterlogged soil.
Use spade, string and waterlogged soil. You should have access to some land that is badly drained.
1. Plant roots need air to breathe. If there is no air in the soil because the soil is full of water you say the soil is waterlogged. Most plants cannot grow in waterlogged soils except some plants that grow in swamps. You can tell when a soil is waterlogged by 1. the soil is always wet 2. the soil has a funny smell 3. swamp plants may grow in it 4. most useful plants die in it. You change waterlogged soil into good soil with a drain. The depth of the drain will be the depth of the well drained soil.
2. There are two kinds of drains: open drains and covered drains. Open drains must be kept clear of plants. Covered drains can be under a field. They are made by digging a small open drain, nearly filling it with flat stones, cover the stones with wood or plastic, then replace the soil. Covered drains can be in concrete pipes under roads.
Extra Activity: Take the children to some waterlogged soil. Dig a hole. Let the children smell the soil. Find the direction of the slope of the land. Show where you would dig a drain. Follow some local drains. Where do they come from and where do they go? What is their purpose? Sentence completion: Soil that is full of water is called [waterlogged]. Most plants cannot live in this soil because the plant roots cannot [breathe]. You can improve waterlogged soil by [draining it].

3.37. Air takes up space
See diagram: 4.303 | See diagram: 20.3.0
Be able to explain that air takes up space.
Use two small jars, large bowl of water, cork.
1. Hold a small jar upside down over a large bowl of water. Float a small cork on the surface then push the mouth of the jar down over the cork until the jar is underwater. The cork is now floating down in the water because air has occupied space.
2. Hold two jars under water one contains air and the other is full of water. Tilt the jar full of air up to transfer bubbles of air into the second jar.
3. Place a jar full of water in the bottom of the bowl. Use a straw or rubber tube to blow air into the jar. The jar will start to float.
Extra Activity: What causes the bubbles? [When air replaces some water.] Sentence completion: Describe what is happens when you blow air through the rubber tubing. The air [replaces the water].

3.38. Float a hair pin
See diagram 4.213:
Objective: To show that small objects can be made to float or sink.
Use pin, soap or detergent. A clean pin washed in hot water that does not contain soap, some soap or detergent solution. Try this demonstration before the lesson.
1. Show the children how you can make a pin float on water. Explain that water has a kind of skin on it. Add some drops of detergent or soap solution. The pin will sink. Soap or detergent breaks the skin of the water that lets the water mix with other things.
2. If you have seen animals walking on water? [Water-strider beetles.] If you have seen animals hanging onto the water skin. [Mosquito larvae.] How do you kill them? [Add oil to the water.] Why is soap or detergent used in washing? [It breaks the water skin and lets the water mix with the dirt.] Why is the detergent or soap added to insecticides or sprays? [It lets the sprays mix well and wet the plant leaves.]
Extra Activity: Floating pins. Repeat the demonstration with other pins or needles. Sentence completion: Water is covered by a thin [skin] that which can be broken when you put [soap or detergent] in the water to wash your clothes.

3.39. Convection heat snake
See diagram 4.29: Heat Snake
Be able to show that hot air rises, by using the heat snake.
Use cardboard, string, scissors and candle sticks. Practice cutting out the shape of a heat snake. Join the string through a hole on the snake's nose.
Show the children how to cut a heat snake, draw the face and attach the string. Hang the heat snake by the string so that it is suspended freely. It should turn slowly. Hold the snake over a lighted candle. It should turn quickly. Why does the snake turns quickly? [It turns because the candle flame heats the air that then rises quickly, this is called a convection current.]
Extra Activity: What would happen to air when it passes over a hot island? [The air rises over the land.]
Sentence completion: [Heated, cooled, rises, falls] When air is [heated] it [rises] and can move things such as the heat snake.

3.40. Paper aircraft
See diagram 13.2.8: Paper aircraft
Be able to explain how changes in the shape of a model plane affects its flight.
Use a paper aircraft or paper to construct one.
1. Show the children how to make a paper plane. Throw the plane to make it fly straight. Who can throw the plane the greatest distance?
2. Now tell the children to bend the end of the tail to make a rudder. If the rudder is bent to the left, and the plane is thrown straight ahead, in which direction will the plane go? [Turn to the left.]
3. Now tell the children to bend the ends of the wings to make elevators. How do the elevators change direction of the flight of the plane? [Nose goes up when elevators go up, nose goes down when elevators are down.]

3.41. Air / water change places
Be able to show that air can replace water.
You will need an empty coffee tin or jar with a tight fitting lid. Make 2 small holes on opposite sides of the lid. The lid must fit tightly. if there is only one hole in the lid both air and water are trying to move through the hole in opposite directions so that the water does not easily come out. With two holes in the lid air enters through one and water can come out through the other. If coconuts are available, step three could be done rather than discussed.
1. Fill the tin or jar with water and put the lid on tightly. Turn the tin or jar upside down and see what happens. [Water drips slowly out of both holes.] Turn the jar so that water comes out of only one hole. What happens at the hole that is not letting water through? [Air bubbles in.] How do your stop the water from coming out? [Block one hole.]
2. How do you hold the tin to get water come out fastest? [Show how because the position changes.]
3. Discuss pouring water or milk out of a coconut or a sealed packet of drink. Are two holes better than one? [Yes.] Why? [The drink comes out quicker if air goes in one hole and water goes out through the other hole.]
Extra Activity: Fill long necked bottles with water, turn them upside down quickly and watch the way air replaces water. Sentence completion: Tell them why do you make two holes in a tin of milk or drink: One hole is to [let the drink out]. The other hole is to [let the air in]. Air [replaces] the drink.

3.42. Things that burn
Be able to test different materials and classify them as things that burn or do not burn.
Use a candle or burner, test materials, e.g. wire, paper, cardboard, dry and green wood, glass, plastic, steel wool, food, chalk bamboo or metal clamps for holding materials in flame a concrete or earth floor under the burning materials.
Put one object in the clamp. Hold the object over the candle flame. Watch the object to see if it catches light. Let it burn if it catches alight. Repeat the test with all the things given them. Make a list on the chalk board and divide it into two groups or sets: things which burn, and things which do not burn. Which set does each item belong to? Fill in a table to classify the materials.
Extra Activity: Heat a sample of garden soil. Does all of it burn? [No.] Does some of it burn? [Yes, the plant material burns.]