School Science Lessons
2024-03-13
Primary Science Lessons, Year 3
(year 3
Contents
Suggested answers to the teacher's questions are shown within [square brackets].
3.41 Air and water change places
3.37 Air takes up space
3.01 Ants life cycle
3.42 Burn different substances
3.07 Burn with a magnifier
3.03 Butterfly life cycle
3.06 Care for cats
3.39 Convection disc, heat snake, hot hand
3.13 Different bones
3.09 Different colours
3.28 Different stems and roots
3.04 Grasshopper
3.14 Make a model insect
3.38 Float pins on water
3.27 Leaf classification
3.26 Leaf collection
3.18 Measure our fist volume
3.15 Measure our height
3.24 Measure our weight
3.21 Measure with trundle wheel
3.20 Measure with wheels
3.14 Model insect
3.02 Mosquito life cycle, Mosquito control
9.1.0 Methoprene, C19H34O3
9.2.0 Bti insecticide, Bacillus thuringiensis
3.16 Move your arms
3.40 Paper aeroplane
3.25 Plant parts
3.17 Plumb bob (vertical test)
3.30 Prepare plant dyes
3.10 Rainbow colours
3.29 Seeds and fruits
3.19 Single pan balance
3.34 Soil air
3.32 Soil animals
3.35 Soil contents
3.31 Soil nutrient cycles
3.33 Soil water
3.43 Solid, liquid and gas
3.11 Spin colour disks
3.44 Squeeze materials
312 String telephone, vibrating cans
3.22 Throw up and down
3.05 Uses of animals and plants
3.08 Water waves
3.36 Waterlogged soil
3.01 Ants life cycle
See diagram 9.34.2: Ant life cycle
See diagram 9.3.33: Ant observation nest
See diagram 9.29: "Ant sucker"
Teach the children to describe the individual behaviour and social behaviour of an ant colony.
1. 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.
2. 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.
Are all the ants the same? Do any ants have wings? Draw the different kinds of ants.
3. 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 an 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.
4. 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.]
5. 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 chalkboard.
Ask the children why is it called a life cycle.
6. Make a collection of ants preserved in methylated spirits.
3.02 Mosquito life cycle
| See diagram 9.8.0: Life cycle of mosquito
Teach the children to identify the different stages in the life cycle of the mosquito.
Use 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 heart worm 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.
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.
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.
4. Collect the different stages of the mosquito life cycle: eggs, pupae, larvae, male and female adults.
The eggs usually cluster together to form a raft.
The pupa is unusual, because it can wriggle.
Keep the different stages in a large screw top jar or an aquarium with a glass top.
Put water weed in the jar or aquarium.
Do not allow adult mosquitoes to fly out and bite people, because of the diseases carried by mosquitoes.
5. The mosquito can most easily be controlled during the larva stage when it lives in water for a long time.
Draining the water or adding insecticide to the water kill the larvae and control mosquitoes.
6. Observe diagrams of the Anopheles mosquito that carries malaria fever caused by the parasitic protozoan Plasmodium.
Discuss how to control mosquitoes near the home.
7. The main sites for mosquito breeding are as follows:
7.1 Salt marsh mosquitoes breed in low-lying land near the sea and in tidal drains.
7.2 Freshwater mosquitoes breed in temporary ground pools, drains, swamps, roadsides, parks, and reserves.
These breeding sites attract more mosquitoes than permanent pools or running water where fish may eat the mosquito larvae.
7.3 Container-breeding mosquitoes breed in "natural" breeding places, e.g. tree cavities that full with water after rain and hollows in bromeliad plants and palms.
They also breed in rubbish and discarded containers, e.g. pot plant saucers, plastic containers, bird baths, motor car tyres and water tanks.
8. 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.
8. Male mosquitoes have a higher pitch humming sound than female mosquitoes and they are attracted by the musical note of a B-flat
natural tuning fork.
Female mosquitoes are attracted by moisture, e.g. sweat, milk, e.g. lactating female, carbon dioxide and body heat.
9. Control of mosquitoes
9.1.0 Methoprene, C19H34O3, is non-toxic to humans and can be used in drinking water to control mosquitoes, because it acts as a growth regulator to prevent the mosquito larva from changing from a pupa to an adult.
9.2.0 Bti insecticide
Bti insecticide (Bacillus thuringiensis subspecies Israelensis strain EG2215) (Bti), forms when this bacterium is in unfavourable circumstances to form spores and die.
Bti is effective in killing mosquito larvae.
The serotype H14, Bti, produces 4 main toxins (Cry4Aa, Cry4Ba, Cry11Aa and Cyt1Aa) specific to dipterans (mosquitoes, blackflies and chironomous midges).
In Australia, "Barmac BTI granules" are used in salt marshes at 7.0 kg / hectare to control the salt marsh mosquito, Aedes vigilax at the 3rd instar or younger larval stage.
3.03 Butterfly life cycle
See diagram 9.7.0: Butterfly life cycle
Teach the children 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.]
Does it have a tongue? [Yes, a rolled tongue that they can unroll to lick honey.]
3. Put caterpillars in a box and feed daily on fresh leaves, e.g. silkworms on mulberry leaves.
Observe and record the development of the caterpillars each day.
Record all changes from caterpillar to cocoon to the fully developed butterfly phase.
Note the time required for the individual phases.
Release the fully developed butterflies.
4. Keep some butterflies in a jar to try to see all stages in the life cycle.
Draw the life cycle of the butterfly.
3.04 Grasshopper
| See diagram 9.9.1: Cockroach
| See diagram 9.9.2: Grasshopper
Teach the children 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.]
3. Make a model insect of a butterfly or a grasshopper.
3.05 Uses of animals and plants
Teach the children to explain how you use plants and animals to satisfy your basic needs.
The 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
3. List the plants and animals you use which are 1. grown locally 2. imported.
3.06 Care for cats
See diagram 9.309: Parts of a cat
Teach the children to care for a pet cat.
Use 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?
5. 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.]
3.07 Burn with a magnifier
See diagram 23.3.7: Burn with a magnifier
Teach the children to: 1. use a magnifier to make things look bigger 2. burn things with the rays of the sun.
Use a magnifier and paper.
Try 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 to upside down.]
4. 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.
3.08 Water waves
See diagram 25.3.1.3: Make water waves
Teach the children 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.]
5. 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.]
3.09 Different colours
Use the following:
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.
Teach the children to describe colours and mixtures.
1. Describe the following:
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, hair,
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.
For exanmple: "Green makes me calm, and 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:
2.1 if you do not stir it,
2.2 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.]
4. 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 Rainbow colours
See diagram 28.220.1: Make a rainbow
Teach the children 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.]
4. Use 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.
3.11 Spin colour disks
Teach the children 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 they form white light.
So 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 as if they are added together.
Ask the children, what does that tell you about white light? [White light is made of the different colours added together.]
4. Use blue, green and red cellophane or glass.
Hold the three colours up to the sunlight so that they 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.
The different colours are violet, indigo, blue, green, yellow, orange, red.
When you spin the colour disc the colours together form white.
3.12 String telephone, vibrating cans
See diagram 26.195: String telephone
(This experiment is also called "vibrating cans", because it uses vibrating metal drink-cans.)
Teach the children to explain that sound can travel to and from solids through a tight string.
Use two paper cups or the tray in two match boxes, hard twisted string (not soft cotton string that does not stretch), two match sticks.
Telephones are important modern communication instruments.
They transmit sound through solids.
1. Punch a small hole in the bottom of a metal drink-can.
Pass a string or fishing line through the hole with its end tied in a big knot or tied to a match stick inside the can.
Rub a resin on the string.
Hold the can with one hand and keep the string tight with the fingers.
Draw the fingers along the string.
Sound comes from the metal can.
Repeat the experiment by drawing the fingers along the string at different speeds.
Note the different pitches of sound.
Drag a wet paper towel along the string or rub your wet fingers along the string.
Some people say it sounds like a duck or a chicken.
2. Repeat the experiment with soft styrofoam cup instead of a metal drink-can and tooth picks that be easily poked through the
styrofoam.
The sound quality exceeds that when using tin cups, plastic cups and paper cups.
3. Cut the lids out of two used tin cans or use two plastic cups.
Punch a small hole in the bottom of each can or cup.
Pass cotton or fishing line or string through the holes with the end tied in a big knot or tied to a matchstick inside the can or cup.
Pull the string tight.
One person speaks into the can or cap while another person presses the other can or cup to the ear.
Sound waves travel along the string to the bottom part of the can, which acts as a diaphragm.
Vibrations of the diaphragm transmit the sound waves through the air to the ear.
Describe what happens when you speak into this telephone.
4. Cut the lids out of two used tin cans or use cylindrical cardboard food cartons with a metal lids.
Punch a very small hole in the bottom of each tin can and push the ends of several metres of thin cotton string through the holes.
Attach matchsticks or a small nut to the ends of the string inside the tin cans or tie a big knot in the ends.
If you cannot punch a hole through the bottoms of the tin cans attach the ends of the string with adhesive plaster or glue.
Pull the string tight and talk and listen to the other person.
The speaker holds the tin can tightly to the face and speaks into it.
The listener person holds the other tin can tightly over the ear and listens.
The string telephone does not work around corners, because the string must not touch any object.
The speaker should first speak very loudly and then speak very softly.
Sound waves from the speaker's voice cause the bottom of the tin can to vibrate.
This vibration then moves along the tight string and then into the bottom of the listener's tin can.
The bottoms of the tin cans act as diaphragms.
Vibrations of the diaphragm of the listener's tin can transmit the sound waves through the air to the listener's ear.
3.13 Different bones
See diagram 9.231: Skeleton.
See diagram 9.232: Arm joint.
Teach the children 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?
1.1 skull and jaw bones,
1.2 backbone,
1.3 shoulder and hip bones,
1.4 ribs,
1.5 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.
4. 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.
Feel your bones
Teach the children to observe types of joints and explain how they 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, so you can swing your 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 they allow growth, e.g. a very young baby has a hole in the skull where
the bones have not joined.
2. Show 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)]
3. 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.
3.14 Model insect
Teach the children to make a model insect and name its parts.
Use a completed model insect: plasticine or clay, dead insects (one for each child), magnifying glasses, many 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 your insects, the three main body parts, the six legs, the feelers, eyes, wings (if any.]
Make a model of your 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 your models with those of other groups.
Name your insect models. Which group has the best model? How many parts of the body? [three]
How many eyes? [two]
How many antennae? [two.]
How many legs on the middle part of the body? [six]
How many wings on the middle part of the body? [four]
3.15 Measure our height
Teach the children to mark their height on the wall for further measurement.
1. Find a place in the classroom where you can mark heights of children with a ball point pen or felt pen.
You must have permission to draw on the school wall for this purpose.
2. Children should know how to mark their heights to see how they are growing.
Show the children how to stand against the wall: feet together, heels against the wall, back against the wall, hands to the sides, head
against the wall, look straight out.
Show the children how to measure the height using a book or a ruler at right angles to the wall, mark the wall with their initials and write
the date.
3. Practice measuring the height of other children.
Mark their height on a wall at home.
Teach the children to:
1. measure the height of all the children in the class,
2. record the height in writing and as a bar graph.
1. 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
2. Draw a bar graph to nearest centimetres, e.g. 152 cm.
3. 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 chalkboard 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.
4. Measure the children again months later.
Show the new heights as extensions of the bar.
3.16 Move your arms
See diagram 9.232: Movement of the arm
Teach the children to display the action of muscles in the arms and legs.
Try out this lesson on yourself before teaching it.
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 bends.
Tell the children to feel and see their muscles and joints working.
6. 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?
3.17 Plumb bob (vertical test)
See diagram 3.17: Plumb bob
Teach the children to make and use a plumb bob.
1. Cut out a 15 cm × 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.
2. 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 Measure our fist volume
Teach the children 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.
Use 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. Draw a line along the first line on the skin of the wrist.
Put the elbow on the desk and look at the palm of the hand.
Above the line is the hand.
Below the line is the wrist.
Curl the fingers and thumb together to form a fist above the line.
Mark the original level of water in a container. Put the fist into the water up to the line on the wrist.
Mark the new level of water in the container.
Open the fist under water.
The new level of water remains the same.
Take out the fist.
Pour water from a measuring jug until the level is at the new level of water.
Discuss how to measure the volume of a whole student.
2. 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.]
3. 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).
4. Use the overflow method.
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.]
5. 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.]
6. How do 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
See diagram 8.12: Balances
Teach the children to measure the weight of different objects using a single pan balance or kitchen scale.
Use a large clock face scale balance, e.g. kitchen scale, Salter clock face, plastic, with pan, weighs up to 5 kg, top pan balance/ 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.
Use 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 chalkboard.
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.
7. If you have both 100 kg and 250 g balances, hook them together then pull them outwards.
What are the readings on the balances? [They are the same.]
If you have two top pan balances, push the tops together.
What are the readings on the balances? [The same.]
8. Repeat the above experiment with a digital top pan balance, e.g. Sunbeam digital, zero function, 800 ml bowl, weight 2 g to 5 kg.
Weigh some sizeable objects using the balances.
3.20 Measure with wheels
Teach the children to use wheels 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 the children how to make an axle.
Use a banana stalk, bottle tops, cotton reels and wire.
Also collect a motor car tyre, a rim and an iron hoop.
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 many times 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.
6. Put a mark on a car tire 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 tire goes around 14 times.
3.21 Measure with trundle wheel
See diagram 2.0.9: Trundle wheel
1. Teach the children 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.
Use 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.
6. 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.
7. Teach the children to measure distances along the ground using a trundle wheel.
Use a piece of plywood or metal sheet at least 32 × 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 with 5 cm increments.
Plastic trundle wheels may have counter clicks each metre to allow the user to see and hear the measurement
3.22 Throw up and fall down
See diagram 8.151.1: Throw up and fall down
Teach the children 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.
Use 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 2? [1. = 2., time to go up = time to come down]
3.23 Volume of a liquid
See diagram: 2.1.6: Volume of a liquid
Teach the children 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 chalkboard.
3. When you measure liquids: the scale and container should be vertical (show this), the eye should be in the same line as the flat water
surface, 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.]
4. 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.
Measure the volume of liquids in litres and millilitres.
Measure volume with a measuring cylinder or measuring jug.
3.24 Measure our weight
Teach the children to compare the weight of each child in the class.
1. Use a bathroom scale or sling scale to record the weight in kilograms of each child.
This provides an accurate record of weight which can be used when studying the health of children.
Also, it can be used to place children in order of weight.
This method only allows you to place children in order of weight.
It involves using a see-saw.
The main goal here is to assist the development of the idea of rank order but it also draws attention to the very small children who may
be underweight and not healthy.
2. Mark a scale of weights on the wall, weigh each child on the scales and write the child's initials on the wall next to the child's weight.
3. Line up the children in order of weight.
Are boys heavier than girls? [At the same age most boys are heavier than girls.]
Now tell the children to line up in order of height.
Is it the same order? Are boys taller then girls?
4. Divide the class into age groups, each child in the group has the same age.
Do the children in each age group have the same weight? Do they have the same height? Which age group has the biggest difference in
height or weight?
5. Make a see-saw.
When no children are on the beam, it should be horizontal.
Let the children sit on the see-saw to work out the rank order, heaviest child to lightest child.
6. Line up in order of weight.
Are boys heavier then girls?
7. Now tell the children to line up in of height.
Is it the same order? Are boys taller than girls?
8. Divide the class into age groups, each child in the group has the same age.
Do the children in each age group have the same weight? Do they have the same height? Which age group has the biggest difference in
height? Which age group has the biggest difference in weight?
2. Teach the children to measure your weights and show them on a chart.
This lesson is the first of a continuous activity that will last for months.
Giving children measurement and recording skills is important so that they can make a visual record of the increase of their height and
weight.
Different people such as doctors, nurses and agricultural officers use such records to check whether people, animals or plants are
growing properly.
They will need to draw two wall charts.
Choose the same day each month from the date of this lesson, e.g. 15th day of the month.
1. Show the weight charts.
Decide where to stick them on the wall. Revise how to measure weight.
Let each child measure their weight.
Let each child ask another to measure their height.
2. Show how to find the place on the chart.
If the date is the 15th of June, draw up a line from June.
Then mark each weight on the line with a cross.
3. Write the initials of the child next to the cross.
Explain later how they will read the charts: Weight chart: In June Jill was heavier than Jim.
In September they were the same weight.
In November Jim was heavier than Jill.
Jim increased in weight faster than Jill.
The line joining Jim's weight was steeper than the line joining Jill's weight.
4. Height and weight chart
Remind the children on the same date each month to measure their heights and weights and record these on the charts.
3.25 Plant parts
See diagram 9.53: Parts of a plant
Teach the children to identify the parts of a flowering plant,
Use 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.
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?
6. 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 Leaf collection
See diagram 9.66.2: Leaf collection
Teach the children to collect different shaped leaves and classify them.
Use different shaped leaves.
1. Give each group a pile of leaves from different plants.
Show that all leaves have three parts:
1.1 The largest part is thin and flat. [leaf blade]
1.2 The thin and round part is like a handle. [petiole]
1.3 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 1. contains hand-shaped leaves, e.g. chilli, hibiscus, taro.
Pile 2. contains long and thin shape leaves, e.g. mango, coconut leaflets.
Pile 3. contains dented shapes, e.g. passion fruit, snake gourd, papaya (pawpaw).
Pile 4. 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?
6. 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.
3.27 Leaf classification
See diagram 9.66.1: Shapes of leaves
Teach the children 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,
and 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, simple / compound and network / parallel veins, and tell you the character of each class.
Let the children discuss this.
2. Draw the character of simple or compound leaf on the chalkboard.
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.
4. Name some plants with simple leaves, compound leaves, leaf veins in a network, leaf veins parallel.
4. 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.
3.28 Different stems and roots
See diagram 9.57.3: Stems
See diagram 9.57.5 Fibrous roots
See diagram 9.57.6 Taproot
Teach the children 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:
* hibiscus, weeds, small woody plants, woody stems and tap roots,br> * beans and peas, soft stem and tap root grass, bamboo, maize, stem divided into sections and fibrous roots,
* grass, bamboo, maize, stem divided into sections and fibrous roots,
* pumpkin, melon, hollow stem and tap roots,
* banana, no stem and fibrous roots,
* sweet potato, yam, taro, swollen stem,
* 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 the children 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.]
Teach the children to recognize different roots and stems and classify them.
Before the lesson walk around the school grounds and note the different kinds of roots and stems.
Take some roots and stems into the classroom.
Use different kinds of roots and stems.
1. Show the plants.
Can you see the roots? [They are very thin.]
Can you see the stem? [Stems are usually above the ground.
Leaves and roots are joined to stems.]
Some plants have underground stems where food is stored, e.g. ginger, sweet potato, taro, yam.
2. Take the children outside.
Find the following:
2.1 a woody stem, e.g. Eucalyptus, mango, sugar cane, coconut,
2.2 soft stem, e.g. pumpkin,
2.3 Grass stems have overlapping leaf bases, e.g. grasses, rice, banana, maize.
3. Look at the roots of a small tree and a grass.
How are they different? [A small tree has a tap root, but grass has lots of little roots.]
4. Make a classroom display of different kinds of roots and stem
3.29 Seeds and fruits
See diagram 9.113.2d: Bean seed
See diagram 9.100.4: Berry, drupe, legume
Teach the children to recognize different types of seeds and fruits.
Use different kinds of fruits and seeds, including a legume.
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 they 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 chalkboard.
Name of plant Maize 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 maize (corn) 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?
3. 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 Prepare plant dyes
Teach the children to make plant dyes and use them.
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.
Use something to crush the plants, e.g. mortar and pestle, a tin that can be heated, cloth, and mordants for permanent dying.
Use 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),
Turmeric root (yellow), Onion skin (yellow), Bamboo (green), Fern (brown), Lichens (orange / brown), Geranium flowers (red),
Morning glory flowers (yellow).
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. Make permanent dyes
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).
Squeeze out the mordant then boil material in the dye.
3.31 Soil nutrient cycles
See diagram 6.65.1: Soil nutrient cycle 1
See diagram 6.65.2: Soil nutrient cycle 2
Teach the children to explain that plant foods are in the soil.
Plants can absorb something out of the soil that you use as plant food.
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 do plants need to grow? Have you seen plants growing in the dark under a stone or under a house? [No.]
Plants need sunlight to grow and 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.
7. 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.
3.32 Soil animals
See diagram 9.306 : Soil animals
Teach the children 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.
List the 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?
5. 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.
3.33 Soil water
See diagram 6.10: Soil water
Teach the children 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? [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.]
6. 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 6.02: Soil Air 1.
See diagram 35.6.4: Soil air 2.
Use four jars or glasses of the same size.
1. To find which soil contains the most air, fill one jar with clay soil and the other with sandy soil.
2. Place full jars of water over each jar of soil.
Any air in the soil will bubble out and displace water from the jars.
Which jar collected the most air? Which soil contained the most air?
3. Test the air content of the soil in your school garden.
Cover a full glass of water with a card or plastic sheet.
Turn the glass upside down.
Place the glass on top of a full glass of dry soil.
Remove the plastic sheet or card.
Teach the children 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? Use 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.
4. Do the experiment again with sandy soil and clay soil? Which has more air? [Sandy soil.]
3.35 Soil contents
Soil is weathered rock material containing minerals plus water, air, organic matter and living organisms.
Soil forms a thin layer on the earth's surface.
It is the growing medium for all terrestrial plants including forests and agricultural crops.
The approximate major components of a soil by volume are as follows: minerals 45%, air 25%, water 25% (after rain, not air dry).
The five main components of soil:
1. Mineral particles, the inorganic fraction derived originally from rocks by weathering.
The main particle sizes are sand, silt and clay.
2. Organic matter, the dead and decaying plants and animals, and animal products.
3. Water, the soil solution in which nutrients for plants are dissolved.
4. Air, atmosphere that fills the spaces (pores) between the soil particles not filled by water.
5. Organisms, ranging in size from small animals to bacteria.
Teach the children to divide a sample of soil into different parts to see what it is made of.
Use a 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 × 10 cm × 10 cm.
Sort the soil into three parts:
1.1 any living things (plant or animal parts),
1.2 any things that were once living, but are now dead,
1.3 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.
Which group can find the most things.
3. Make a table on the chalkboard 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
4. 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.
3.36 Waterlogged soil
Teach the children to examine the soil and find out if it is waterlogged.
Determine how to drain a waterlogged soil.
Use a spade, string and waterlogged soil.
You need 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 the following:
1.1. the soil is always wet,
1.2. the soil has a funny smell,
1.3. swamp plants may grow in it,
1.4. 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, replace the soil.
Covered drains can be in concrete pipes under roads.
3. 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?
Most plants cannot live in waterlogged soil, because the plant roots cannot breathe.
You can improve waterlogged soil by draining it.
4. Plants vary in their ability to survive periods of waterlogging.
Species differ and some strains or cultivars are superior to others.
Observe which plants have survived in waterlogged areas in your district, and those that are abundant on well-drained sites.
Test whether species found in waterlogged conditions can survive waterlogging better than others.
Experimental problems include at what stage of growth to flood plants, depth of flooding, how long to flood, how to measure recovery.
5. Waterlogging, "wet feet" of many plants, e.g. olive, rosemary, even for small periods, can predispose them to root rot and other
disorders that affects tree growth and survival. In high rainfall areas, waterlogging may be a major constraint to soil health and crop
yields, e.g. grain legume, oil-seed and cereal crops early in the growing season.
6. Cassava, cocoa, coconuts, and taro will not grow well in waterlogged soil.
3.37 Air takes up space
See diagram: 12.303.1 Air in a bottle
1. Air in a bottle
Place the funnel in the neck of the bottle.
Seal the space between the funnel and the neck of the bottle with heavy grease or Plasticine (modelling clay).
Pour water slowly into the funnel.
The water stops running, because the air takes up space.
Repeat the experiment and pour in water until it comes nearly to the top of the funnel.
Use a nail to punch a hole through the seal.
All the water drops into the bottle.
The water replaces the air that comes out through the punched hole.
2. Air in a drinking glass
See diagram: 12.303.2: Air in a drinking glass
2.1 Float a cork on the surface of a bowl of water.
Invert a drinking glass over a bowl of water, then push the mouth down over the cork until the drinking glass is under water.
The cork is now floating down in the water, because air has occupies space in the drinking glass.
2.2 Scrunch up some newspaper in the bottom of a dry drinking glass.
Invert the drinking glass and shake it to ensure that the paper is squashed against the sides and will not fall out.
Invert the drinking glass over a bowl of water, then push the mouth down until the drinking glass is under water.
The newspaper remains dry, because air has occupies space in the jar.
3. Blow air bubbles
See diagram: 12.303.4:
Place a jar full of water in the bottom of the bowl.
Use a plastic tube to blow bubbles of air into the jar.
The jar will start to float.
4. What causes the bubbles? [When air replaces some water.]
3.38 Float pins on water
See diagram 4.213 Float a needle
Teach the children to show small objects can be made to float or sink in water.
Use a 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.]
3. Repeat the demonstration with other small objects.
Water is covered by a thin skin, which can be broken when you put soap or detergent in the water to wash your clothes.
3.39 Convection disc, heat snake, hot hand
See diagram 23.127: Convection disc, Heat snake, Hot hand
Teach the children 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.
1. 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 rises quickly, called a convection current.]
2. Fold a rectangular piece of paper along the middle and across a diagonal. Balance the folded paper over the end of a sharp pencil where the two folds cross. Keep still while holding the pencil tightly in your fist. The folded paper will start to revolves as heat rises from your hot hand. 3. What would happen to air when it passes over a hot island? [The air rises over the land.]
3.40 Paper aeroplane
See diagram 13.2.8: Paper aeroplane and paper aircraft
Teach the children 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. 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. 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 and water change places
Teach the children to show that air can replace water.
Use an empty coffee tin or jar with a tight fitting lid.
Make two 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.]
4. Fill long-necked bottles with water, turn them upside down quickly and watch the way air replaces water.
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.
So air replaces the drink.
3.42 Burn different substances
Teach the children to test different substances and classify them as 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.
1. Put one substance in the clamp.
Hold the substance over the candle flame.
Watch the substance to see if it catches light.
Let it burn if it catches alight.
Repeat the test with other substances.
2. Make a list on the chalk board and divide it into two groups: substances that burn, and substances that do not burn.
3. Heat a sample of garden soil.
Does all of it burn? [No.]
Does some of it burn? [Yes, the plant material burns.]
3.43 Solid, liquid and gas
Teach the children to observe solid, liquid and gas in a plastic drink bottle.
1. Screw the cap tightly on an empty plastic drink bottle.
Pick up the bottle and squeeze it in your hand.
You can squeeze the bottle and change its shape, because the bottle is full of the gases in the air.
Gas particles move at great speed and at a great distance apart so they can be squeezed together.
Gases are compressible.
If you unscrew the cap you can squeeze out most of the air in the plastic bottle.
2. Fill the plastic bottle with water and replace the screw cap.
Do not leave any air in the bottle under the screw cap.
Try to squeeze the bottle full of water.
You cannot squeeze the plastic bottle, because liquids are not compressible.
Liquid particle are close together, but can roll over each other.
Liquids are not compressible.
The liquid particle s are like marbles in a drawstring bag pulled tight.
If you unscrew the cap you can squeeze out most of the water in the plastic bottle.
Gases and liquids can flow so they are called fluids.
3. Put the bottle filled with water in a freezer.
The water freezes to form the solid ice.
You cannot squeeze this solid.
The particles in a solid are close together and maintain their relative position so a solid keeps its shape.
Solids are not compressible.
If you unscrew the cap you still cannot squeezes the ice out of the container.
3.44 Squeeze materials
Teach the children to squeeze different materials and observe how they respond.
Squeeze different materials with a potato masher, note what happens when you increase the force, and then decrease the force until
you remove the potato masher.
1. Some materials spring back to their original shape, elastic materials, e.g. rubber eraser.
2. Some materials keep the shape when the greatest force was applied, inelastic materials, e.g. Plasticine (modelling clay), wet clay.
3. Some materials break into small pieces, brittle materials, e.g. spaghetti, glass.
4. Some materials do not change shape, tough materials, e.g. steel.