year6

School Science Lessons
Primary Science Lessons Year 6
2009-10-16
Please send comments to: J.Elfick@uq.edu.au
Suggested answers to the teacher's questions are shown within [square brackets].
Lessons

Animals	Food chains in the forest	Protect our turtles	Chicken life cycle	Pig life cycle	Fungi Bacteria	Mouldy bread and rotten fruit
Energy	Heated liquids expand	Water climbs up string	Pull with pulleys	Forces on coins on a slope	Floating and sinking	Forces of friction
Human body	Shakir strip and malnourished child	How far you can see	Measure air breathed out	Male reproduction organs	Female reproduction organs	Birth and care of a baby
Measuring	Measure relative humidity	Measure air pressure	The moon and tides	Southern Cross constellation	Estimating	Pendulum tells the time
Plants	Trees and shrubs	Protect our trees	Describe grasses	Describe palms	Describe ferns and mosses	Planting material
Rocks and soils	Protect our coral reefs	Protect our soils	Describe soils	Test soil texture	Fertilizing soil	Chemical fertilizer
Substances	Burn candle over water	Candle "lava"	Electric circuit	Electricity conductors	Electric torch (flashlight)	Magnets Electromagnets

Table of contents
6.1 Food chains in the forest
6.2 Protect our turtles
6.3 Chicken life cycle
6.4 Pig life cycle
6.5 Fungi (Singular: Fungus)
6.6 Bacteria (Singular: Bacterium)
6.7 Mouldy bread and rotten fruit
6.8 Heated liquids expand
6.9 Water climbs up string and paper
6.10 Pull with pulleys
6.11 Forces on coins on a slope
6.12 Floating and sinking
6.13 Forces of friction
6.14 Shakir strip and malnourished child
6.15 How far you can see?
6.16 Measure air breathed out
6.17 Measure relative humidity
6.18 Measure air pressure
6.19 The moon and tides
6.20 Southern Cross constellation
6.21 Estimating
6.21.2 Estimate total number using areas
6.21.3 Estimate total number using divided samples
6.21.4 Estimate total number using layers
6.21.5 Estimate lengths using your body
6.21.6 Estimate heights
6.21.7 Estimate area of a leaf
6.21.8 Estimate area of a mouse
6.21.9 Estimate weight
6.22 Pendulum tells the time
6.23 Trees and shrubs
6.24 Trees, palms and ferns
6.25 Protect our trees
6.26 Describe grasses
6.27 Describe palms
6.28 Describe ferns and mosses
6.29 Protect our coral reefs
6.30 Protect our soils
6.31 Describe soils
6.32 Test soil texture
6.33 Fertilizing soil
6.34a Chemical fertilizers
6.35 Burn candle over water
6.36 Candle "lava"
6.36.1 Cooling candle wax like cooling lava, speed of cooling and crystal size
6.37 Electric circuit
6.38 Electricity conductors
6.39 Electric torch (flashlight)
6.40 Hanging magnets
6.41 Make electromagnets

6.1 Food chains in the forest
See diagram 9.311: Food chain study
Be able to study animals in the forest and discover food chains.
Use plastic cages.
In this lesson introduce the idea of food chains in the forest and start the children on observing small animals in plastic cages as shown in the figure below. The importance of the food chain is that it teaches children that living things depend on each other. The sign >> means "is eaten by" and shows the direction of the flow of nutrients.
Examples of food chains:
1. leaf >> butterfly >> larva >> lizard
2. Kangaroo grass >> grasshopper >> birds >> round worm parasite
3. Palm beetle >> scorpion >> spider >> bird
4. Dead Casuarina >> fungus >> wood louse >> ant
5. Rotten leaf >> millipede >> toad >> snake >> dog
Before the lesson, prepare plastic cages. Use a plastic drink bottle.
Groups of four
1. Explain the food chains using arrows. Think of some food chains. Use animals in the forest.
2. In the forest telling what eats what is not easy, especially if they are small animals. To enable us to do this you will collect animals and plants from the floor of the forest and study them in plastic cages.
3. Take the children into the forest to collect animals for their cages. Can you see something eating something else? You will need to put different animals together to see what happens to them.

6.1.1 Animals without backbones (Invertebrates)
1. Microscopic single celled animals (Protozoa)
2. Flat worms, parasites in animals (Platyhelminth)
3. Round worms, parasites in animals (Nematode)
4. Ringed worms, earthworms (Annelid)
5. Jointed legged animals (insects, spiders, ticks, centipedes, millipedes (Arthropod)
6. Slugs and snails (Mollusc)
7. Animals with backbones (Vertebrates)
7. 1 Frog, toad (Amphibians)
7. 2 Lizard, tortoise, crocodile (Reptiles)
7. 3 Megapode, parrot (Birds)
7. 4 Flying fox, dog, cat (Mammals)
8. Plants in the forest and grassland
8.1 Green colour in water and wet soil, single celled plants (Algae)
8.2 Moss (Bryophyte)
8.3 Ferns, filmy ferns, bracken, tree ferns, epiphytes (Pteridophyte)
8.4 Pine trees, cycads and palms (Gymnosperms)
8.5 Grasses and shrubs, trees, vines (Flowering plants, Angiosperms)
9. Mould, bracket fungi, mushrooms (Fungi)
10. Aerobic bacteria, need air, anaerobic bacteria, live in mud, both cause rotting. (Bacteria)

6.2 Protect our turtles
See diagram 9.307: Turtle
Be able to explain why you should protect turtles and crocodiles.
Turtles and crocodiles are reptiles. They have a thick skin with scales and lay their eggs on land. In this lesson the teacher should explain that they are interesting animals that are part of your natural heritage. If you killed them with the aid of modern weapons, something that you all own would be lost. There may be a good reason for killing some animals for traditional purposes. Most people are frightened of crocodiles but you should not kill them, just keep away from them.
Both crocodiles and turtles are part of the food chain. In some countries crocodiles are kept in farms for their skins. Crocodiles live in the Laurie Lagoon on Guadalcanal and on the Olu and Malau Islands. You should respect all creatures and let them survive for future generations to study and admire these beautiful creatures. Collect pictures of turtles and crocodiles. Some of these animals are on postage stamps: Green Turtle, Pacific Ridley Turtle, Loggerhead Turtle, Leatherback Turtle, Estuarine Crocodile.
Hawks Bill turtles live near the shore and are easily caught. We seldom eat them but some people kill them to use the shell to make things sold to tourists.
Leatherback turtles are very big and can swim great distances in the open ocean. They are a very old kind of turtle and do not have a bony back shell. They are rare because people eat their eggs when the mother lays them on the land.
Green turtle, Pacific Ridley turtles and Loggerhead turtles are becoming fewer because so many people like to eat them. They catch the mother turtles when they swim to a beach to lay their eggs. In the past people killed only a few turtles for traditional use but now many people use motorboats to catch them and do not respect the old customs. Also large fishing boats from other countries drown turtles when they get caught up in fishing nets.
Turtles cannot lay eggs until they are more than 10 years old. So protecting them now is important or there will be no turtles left for us to watch or eat. What can children do? Do not disturb turtle nests and eggs, let the baby turtles hatch out and get into the sea. Do not catch a turtle when it is moving up the beach to lay eggs. If you see a turtle on a beach, keep it a secret, do not tell everybody, or bad people will kill her before she can lay her eggs. If you are out in a canoe and see a turtle, do not kill it. Tell the teacher where you saw the turtle and what kind it is, then the teacher will give you a prize!
1. Show the pictures of turtles. Ask them if they have seen turtles. What they think about them, should you kill them? Why people kill them.
2. Explain why you should NOT kill them 1. respect for all animals, 2. some kinds of animals should not die out, 3. part of your natural heritage, 4. beautiful creatures that should be admired.
3. Explain why they are in danger of dying out: 1. custom of killing for special occasions or special people. However, some customs are no longer respected. 2. people have motor boats, 4. fishing boats from overseas drown them when the turtles are caught in nets.
4. Explain how they can protect turtles: 1. protect eggs and hatched baby turtles, 2. protect laying mothers, 3. protect turtles at sea.
5. Show pictures of crocodile. What do they think of it? Do they want to kill it? Do they want to protect it?
6. Explain why they should not kill crocodiles: 1. also part of natural heritage, 2. interesting animals, 3. can be farmed.
7. Explain that you should protect it and keep way from it.
Extra Activity:
Turtle sightings.
Encourage the children to report whenever they see these animals. Give a small reward for each sighting.

6.3 Chicken life cycle
See diagram: 50.6.0: Parts of a chicken | See diagram: 2.6:5 Chicken egg
Objective: To explain how the mother hen can make baby chickens.
Discuss the diagram for this lesson with the head teacher before you teach this lesson.
1. Where do baby chickens come from? [Eggs.] Where do the eggs come from? [The mother hen lays them.] What does a hen need to make a baby chicken? [She must mate with a rooster that will put sperm inside her to fertilize her egg.] Then she puts a shell around the egg and lays it.
2. Show the children the diagrams and read the explanations. Most fish and all frogs do not look after their young but chickens always look after their young.

6.4 Pig life cycle
See diagram: 59.01 Pig breeds | See diagram: 59.03: Pig reproduction organs
Be able to explain how the mother pig can make baby pigs.
Discuss the diagrams for this lesson with the head teacher before you teach the lesson.
Where do baby pigs come from? [The mother pig.] Can the mother pig make babies by herself? [No, she needs a father pig to put sperm inside her to fertilize her eggs.] Show them the diagrams and read the explanations: the male pig mates with the female pig. The male sperm fertilizes the female eggs. Each fertilized egg grows into a foetus that gets its food from the mother. The baby pigs are born four months after fertilization. The baby pigs drink their mother's milk and she takes care of them.
Sentence completion: Match the letters 1. 2. 3. 4. with the numbers 1. 2. 3. 4.

The male pig puts the . . .	1. their mother's milk.
The baby pig is born . . .	2. grow inside the mother pig.
The fertilized eggs . . .	3. after four months.
The baby pigs feed on . . .	4. sperm into the female's body

[Answer: 1. 4. 2. 3. 3. 2. 4. (1).]
Extra Activity: From the following diagram explain the parts of the pig. Tell the children to draw a pig and name the parts.

6.5 Fungi (Singular: Fungus)
See diagram 9.201: Mushroom
Be able to describe the characteristics of fungi and state their importance in food chains.
Use Mushrooms, toadstools, mouldy bread
Fungi are not really plants because they are not green and they never get energy from the sun. They get their energy when they digest plants and animals and make them rot. Their method of feeding is more like an animal. Fungi can cause disease and make dead things rot. They can also make useful substances such as penicillin and alcohol. Fungi work with smaller bacteria to decompose plants and animals until they completely rot and return their nutrients to the soil. Imagine if there were no fungi or bacteria, the world would be covered with piles of dead things. If you put your hand in a compost heap, it feels hot, caused by the activity of the fungi and bacteria. Fermenting cocoa also gets hot for the same reason. Most fungi are poisonous so children should wash your hands after touching them. Use some examples of fungi to class.
1. If you have ever broken open some rotten wood, what did you see inside? [White threads and sometimes something growing out of the wood.] This is a fungus that is eating the wood and making it rotten. Use such an example to class.
2. Show the children the different fungi they have collected.
Different kinds of fungi:
1. Toadstools like little umbrellas growing out of the ground or rotten wood. They may be poisonous and glow in the dark, e.g. Calvatia, Filoboletus, Agaricus or Psaliota. 2. Bracken fungi are hard and grow out of the trunk of trees, e.g. Pycnosporus. Some grow on cow dung, e.g. Pilobilus. 3. Some fungi are parasites. They attack living things, e.g. diseases on the human skin and ear, and diseases of cocoa and groundnuts (peanuts) may all be caused by fungi. 4. Yeasts are tiny fungi that cause fermentation. Yeasts change sugar into alcohol. They cause fermentation of cocoa and are used to make beer.
3. Are fungi good or bad? [Fungi that are parasites are bad because they cause disease, all the other fungi are good.]
4. What would happen if there were no fungi to make things rot? [Nutrients would not return to the soil and the world would be covered with dead things.]

6.6 Bacteria (Singular: Bacterium)
See diagram 9.205: Bacteria
Bacteria live like fungi but they are so small you cannot see them except with a microscope but you can see what they do. Dissolve soup powder or cube in a cup of hot water and pour evenly into 3 clean glasses. Add 1 teaspoon of salt to one glass. Add 1 teaspoon of vinegar (acetic acid) to the second glass. Add nothing to the third glass. Cover the glasses and leave them in a warm place for 2 -3 days. The first two glasses remain clear because they contain substances which stop bacteria growing. The liquid in the third glass is cloudy because it contains so many bacteria.

6.7 Mouldy bread and rotten fruit
See diagram 9.196: Rhizopus fungus
Collect waste foods in a sealed glass container see the life of fungi, e.g. cut boiled potato, cut orange, bread. The fungi grow like little threads. They push the ends of the threads into to food to digest it. So they get their food like animals not like plants. If you keep the glass container sealed, you will see water appearing inside the glass for the respiration of the fungi. After a few days the fungi form usually black rounded structures which will burst open to let out tiny spores. The spores are usually carried in the wind to the next food where they grow into a new fungus.

6.8 Heated liquids expand
See diagram 20.1.1: Heated liquids expand
Be able to describe how water expands when heated.
Use A bottle, plastic tube from a ball pen, burners, heating stand, ink to colour the water, cork with a hole through it.
Water expands when heated and contracts when cooled.
1. Give out the materials and tell the children to push the clean ball pen tube through the small hole in the cork.
2. Fill your bottle with coloured water right up to the top. Push the cork gently but firmly into the bottle so that the coloured water is a short distance up the clear tube.
3. Mark on the side of the tube the level of the coloured water. Mark 1.
4. Light your burners. Heat the bottle of coloured water gently on the heating stand. Closely watch the level of the coloured water in the tube. What happens to the level of the water? [The water level rises.] Mark the new level on the side of the tube. Mark 2.
5. Give a reason the water has risen. [It expands when heated.]
6. Take the bottle away from the flame. Watch the level of the water in the tube. What happens to the water level? [The water level falls back to Mark (1).] Give a reason the water level falls. [The water contracts.]
Extra Activity: Show the children a thermometer and show how the mercury level changes when the bulb is placed in hot water and then in cold water. Explain how thermometers are used to measure the air temperature and your body temperature.

6.9 Water climbs up string and paper
See diagram 35.6.7:
Be able to show that water can climb up some substances and that water climbs up different substances at different speeds.
Use Strips of newspaper about 2. 5 cm wide and 30 cm long, pieces of thick string about 30 cm long, tin lids, sticky tape, box, ruler, a clock.
The string and paper should be thick, soft and absorbent. If you do not have any suitable string, you can use another kind of paper torn into thin strips. Put a pin on the end of the paper strip to act as a weight. Use a pencil to mark zero above the pin then draw a mark every centimetre. The level of the water should be at the zero. Before the lesson, set up the experiment and watch the water climbing up the paper and string for five minutes. Draw the results on the chalk board. This lets us see practical aspects of capillarity both at home and among living things.
1. Use the sticky tape to stick the strip of paper and the string to the top of the box. The string and paper must hang down so that they just touch the water.
2. Note the time when you put the string and paper in the water. Watch the strips and string. What happens? [The water climbs up the paper and string.] After five minutes tell the children to measure the heights the water has climbed up the water and the string. The heights are measured up from the surface of the water. Write these heights in your table of results.
3. Repeat after five minutes. Repeat up to 30 minutes. Each child should have a chance of measuring.
4. Does the water climb up farther in the string or paper? Check carefully that the children measure from the top surface of the water in the tin lid, at 0 on the rule, to the top of the wet mark.
Extra Activity: Can you think of anything people use at home where the liquid climbs up a string? [Kerosene climbs up the wick in a kerosene lamp.] Dip a long piece of white chalk into ink. Does the ink climb up? [Yes.] Water can also climb up soil from damp places below to dry places above. This helps plants to get water. Show results on a graph.

6.10 Pull with pulleys
See diagram 21.5.0: Types of pulleys
Be able to use pulleys to change the direction of a pull and to move heavy loads.
Use Pieces of string three m long, small pieces of string 40 cm long, pulleys (fixed and movable), bags full of sand or soil (for loads), sticks or strong rulers.
Draw a diagram on the chalk board showing the way the equipment is set up.
1. Tie the load to the string and pull it along the desk top by pulling the string towards them. Can you move the load away from them and still pull the string towards them?
2. Ask successful groups to show how they did it. [This can be done if a pencil is held by another child at the other end of the desk, and the string passed around the pencil.] Give out a pulley to each group.
3. Use the pulley instead of the pencil and try again. Is it to pull with the pencil or with the pulley? [Pulley.] Why? [The pulley wheel can move freely.]
4. Show the children your chalk board diagram then tell them to set up the fixed and moveable pulleys. Check that each group has arranged the pulleys correctly. Each child should take it in turns to hold the neck of the bag between finger and thumb and pull it. Now use the pulleys. Hold the free end of the long string between finger and thumb and pull so that the bag moves from one end of the desk top to the other.
5. Have you found any differences? [It should be easier when the moveable pulleys are used as in the diagram. The pull should be smaller than in the diagram but the distance pulled will be greater.]
Extra Activity:
How can you lift the load above your heads using the string and pulley? Tie your pulleys to a beam across the classroom roof, and to pull up your loads using these pulleys. What could you use a pulley for? [Lifting heavy loads.] A force can be a push or a pull. Forces cause things to move. If you push or pull a small object it can start to move. If you increase the force, it can move faster. In the same way if you want to stop a moving object then you must push or pull it in the opposite direction. If an object is not moving, it does nit mean that there are no forces on it. An object will not move if there are equal and opposite forces acting on it. When a force causes an object to move then work is done. Sometimes work cannot be done because the object is too heavy. The force needed to move it is too big. Machines make work easier for us by decreasing the force needed to do the work. One type of machine is the pulley. The pulley is a grooved wheel. The pulley with a rope or a chain is used to lift heavy objects or to change the direction of a force. A pulley can be used in two ways: a fixed pulley changes the direction of the force and a moveable pulley makes the force needed smaller. If a fixed pulley and a moveable pulley are used together then the direction of the force is changed and the force needed is smaller.

6.11 Forces on coins on a slope
See diagram 14.2.11: Start and stop | See diagram 16.1.0: Forces
Be able to explain why an object can slide down a slope and move another object.
Use Coins of different sizes and a ruler.
This lesson is designed to train children to observe what happens when a force is increased and to introduce the idea of the force of gravity that causes the mass of objects.
1. A force is a push or a pull. A force can make an object start moving, stop or change direction. In this lesson you will use forces to start things moving and find out why they stop moving.
2. Hold down a 20 cent coin with your finger. Move the coin sideways to hit a 10 cent coin. What does the 10 cent coin do? [It starts moving.] Measure how far it moves. Hit the 10 cent coin again but this time hit it harder. Measure the distance the 10 cent coin moved. What difference did you see? [The 10 cent coin moved faster and farther.] How did the 20 cent coin move? [It moved faster the second time.] Why did the 10 cent coin move faster and farther? [The 20 cent coin moved with more force.]
3. Make a slope with a ruler. Slide a 20 cent coin down a slope to hit a 10 cent coin. Note the height of the slope and how far the 10 cent coin moves.
Table of Results
Height of slope
Distance of 10 cent coin
4. What did you notice about the speed of the 20 cent coin when the height of the slope increased? [It moved faster.] What did you notice about the distance the 10 cent coin moved when the height of the slope increased? [It moved farther.] Why did these increases occur? [The force of the 20 cent coin hitting the 10 cent coin increased as the height of the slope increased.]
10. Put a coin on the flat table. Will it move sideways by itself? [No.] What can make it move sideways? [A force.] Pick up a coin. Can it move by itself? [Yes.] Let it go. What happens? [It falls.] Why did it move? Did you make it move with a force? [No.] Did anything push it? [No.] Did anything pull it? [Yes, it was pulled down by the force of gravity.]
5. The earth pulls all things towards it. This pull is called the force of gravity. Hold a coin in your hand. Can you feel a downwards force? [Yes.] What do you call this force? [The mass of the coin.] The mass of the object is the pull down caused by the force of gravity.
6. When you hold a coin in your hand is there a pull down on the coin? [Yes.] Does the coin move down? [No.] Why not? [The coin does not move down because your hand pushes up the coin. The pull down on the coin is equal to the push up by your hand, so the coin does not move.] When an object does not move this is because the pull down is equal to the push up on it.
7. Slide a coin down a slight slope. Why does the coin slide down? [It is pulled down by the force of gravity.] Why does it slide slowly? [There is some push on the coin by the sloping ruler.] Make the slope steeper. Slide the coin down. Why does the coin slide down more quickly? [The coin is pulled down by the force of gravity. The sloping ruler pushes up less on the coin.] Turn the ruler over. What happens to the coin? [It falls very fast.] Why does it fall so fast? [It is pulled down by the force of the gravity, the ruler does not push up on it at all so there is nothing to stop the coin from falling.] An object falls down when the force pushing up on it is less than its mass.
Extra Activity:
1. Repeat the experiment as above but use a 10 cent coin sliding down to hit a 20 cent coin. What do you see? [The distance the 20 cent coin is pushed along the table is less.]
2. Can you explain why a ripe mango or orange fruit drops to the ground from the tree?
Questions: Part A, Force 1. What is a force? [A push or a pull.] 2. Can a force start things moving? [Yes.] 3. Can a force stop things that are moving? [Yes.] 4. Can a force make a moving thing change direction? [Yes.] 5. Which ball hits your hand with the greatest force, the heavy ball or the light ball? [The heavy ball.] 6. The ball thrown high or ball thrown low? [High.] 7. Coconut on a tree. Is there a force pulling down the coconut? [Yes.] 8. What is the force called? [Weight.] 9. Is there a force pushing up? [Yes.] 10. What is pulling it up? [The tree.] 11. Which force is bigger? [If the coconut stays on the tree then, Force down = force up.]

6.12 Floating and sinking 1.
Objective: To observe things that float and things that sink.
Collect wood, ball, bottle tops, stones and other objects. You will need also Plasticine (modelling clay) or putty, jars, water, bottles, little stones, a container with water.
Let the children make things float. Are you all the same depth in the water? [No Give each group a bottle or Show how to make a paper boat. Add little stones to the floating bottle or paper boat. Do you stay the same depth in the water? [No, you get deeper until you sink. Give the children things that sink including a lump of Plasticine what happens when things sink? [The water level in the container rises. Make a canoe out of the Plasticine. If the walls are very thin, it will float. What is the difference between the Plasticine sinking and floating? [When it floats the water level in the container is higher, the volume is bigger.
Extra Activity: What other things can be made to sink or float? [Galvanized iron canoe, an iron boat.]

6.12.1 Floating and sinking 2.
Be able to explain why an object that sinks in water can be made to float.
Use Plasticine, jar and water.
An object that sinks can be made to float by increasing its volume so that the mass of the object is less than the mass of the water displaced. one mL of water weighs close to one gram. Make the boat by moulding the Plasticine around a small jar. Try out the experiment before the lesson. This will give an idea of the extent to which it can work. This discussion can help in explaining the floating of ships and liners.
1. Half fill a jar with water, mark the level of the water on the side of the jar.
2. Make a piece of Plasticine into the shape of a boat with high sides. Float the boat in the jar of water. What happens to the level of water in the jar? [It goes up.] Why did the level of the water go up? [It was pushed up by the part of the boat under the water.]
3. Now sink the boat. What happens to the level of the water in the jar? [It drops.] What does this new level tell you? [This is the volume of the Plasticine used to make the boat.] Was the volume of the Plasticine greater or less than the volume of the floating boat? [Much less.] What is the mass of the boat?
4. Float the boat again. Add bits of Plasticine so that it floats lower in the water. What has happened to the level of water as the boat floated lower? [It rose.] Why did it rise? [The boat has pushed out more water as it floated lower.] Why did the boat sink down more? [It is heavier or more massive with bits of Plasticine in it.]
5. Add more Plasticine until the boat is just floating. It cannot float any lower without sinking. What is the volume of the boat? [Equal to the volume of the water pushed out.]
6. Find the mass of the water pushed out.
7. Conclusion: An object floats when the weight of the object is less than the weight of the water it pushes out or displaces.
Extra Activity:
1. How does step 7 above explain floating of ships? [The weight of the ships is less than the weight of the water displaced.]

6.13 Forces of friction
See diagram 4.182:
Be able to explain what causes friction and how you can reduce it.
Use three new match boxes, two of them full of sand and the other one full of heavier materials like nails, a heavy book, a piece of string, lead pencils.
You can teach the idea of friction using the previous coin experiment in Stopping and Starting. Remember that friction is both an advantage and a disadvantage. Friction allows us to walk without falling over and to pull a thread with a needle. Smooth car tires have less friction on the road than tires with tread. Which tyre is the safest? Friction is also the cause of wear of the moving parts of engines so you have to reduce friction with lubricants such as motor oil.
1. Rub your dry hands together. What do you feel? [Hands get hot.] Wet your hands and do it again. What do you feel? [Not hot.]
2. Explain that your hot hands are caused by the force of friction. When two things rub over each other there is a force in the opposite direction to the movement called friction. When you wet your hands, they were lubricated with water. The water between the hands reduced the friction. To stop the metal parts of engines rubbing on each other you use oil called lubricating oil.
3. Show the children a matchbox and matchsticks. Where do you strike the match? [Strike on the black part at the side.] Try to strike the match on the smooth part. Why does the match not light? [Because you struck it on the part that is smooth. You must strike it in the black part that is rough where there will be more friction.]
4. Matchbox race
Label the matchboxes full of sand "S" for smooth and "R" for rough. Label the heavy matchbox "H". Do not tell the children what the letter means. Put the three matchboxes in line on the end of the heavy book. "S" is lying on the smooth side. "R" is on its black side. It is lying on its smooth side. Tip up the book. Which matchbox comes first, second and third? Do it often and put the results on the chalk board. Let the children pick up the matchboxes then explain the race using the word friction. Smooth comes first because the force of friction is least between the smooth side and the book, rough comes second because it is sliding on its back rough side so the force of friction is greater. You are the same weight. Heavy comes last because a heavy weight increases the force of friction a lot. You can reduce friction by changing sliding motion to rolling motion. Put a piece of string through a book and roll it along. Now put the book on pencil rollers. What do you feel? [The pull needed is less.]
Extra Activity:
1. Methods of reducing friction The simplest method of reducing friction is to place rollers between the two surfaces. This method is used when boats are launched, or when heavy wooden crates have to be moved. Here linear friction is replaced by rolling friction. Ball bearings are used to reduce friction for revolving shafts. The axle of a bicycle is mounted in ball bearings. The ball race shown is similar to the ball race used in a bicycle. Friction is thus reduced by 1. replacing linear friction with rolling friction, and 2. by using hard surfaces, as hard surfaces have less friction than softer surfaces. Lubrication is the most common method of reducing friction. On a bicycle all moving parts have small holes through which oil is squirted so that the parts that move in contact with one another are covered in oil. On a motor car, grease nipples are provided for the same purpose and grease is forced under pressure through those nipples.
2. How does friction help in increasing or decreasing the speeds of athletes at sports meets?

6.14 Shakir strip and malnourished child
See diagram 9.236: Shakir strip
Be able to discover malnourished small children by measuring their arms with the Shakir strip.
Use The Shakir strip.
People who do not have enough food or do not have the correct amounts of energy food, growth food, and healthy food are said to be malnourished. Malnourishment of young children, especially after weaning, can be very dangerous. They may get sick and die or they cannot learn much when they go to school. It is not easy to tell whether a child is really undernourished or has a temporary sickness. This problem has been solved by the Shakir strip used in many countries. When babies are about one year old, they have much fat under the skin of their arms. When you are five, this fat is not there but there is much more muscle. This means that the circumference of the upper arm is almost the same between the ages of one and five. If you measure the middle of the upper arm of children between the ages of one and five, you can find the malnourished children. Instead of a tape measure you can use a piece of string or a strip of material that does not stretch, e.g. old x-ray film.
1. Children between the ages of one and five should not be malnourished otherwise they may get sick and die. Malnourished children may not learn much when they grow up.
2. Doctors have found a way to tell if children are malnourished by using a marked tape called the Shakir strip. It is one cm wide. The circumference of the upper arm is as follows:
Shakir Strip

Circumference of Upper Arm	Colour Zone	Health of Child
Greater than 135 cm	green zone	Healthy child, not malnourished
Between 125 and 135 cm	yellow zone	Child probably malnourished
Less than 125 cm	red zone	Child certainly malnourished

3. Cut a strip of paper the length of the page and one cm wide. At six cm from one end mark 0 cm. Then mark it at 12. 5 and 13. 5 cm. Colour 0 to 12. 5 cm red, 12. 5 to 13. 5 cm yellow and more than 13. 5 cm green. Give the children a cardboard toilet roll centre or a thin tube to measure. Are they correct?
4. Take the Shakir strip home and measure the arms of all the children with age one to five years. If you find any children in the yellow or red measurement, you should tell the teacher the next day.
Extra Activity: Why may recently weaned children or animals be malnourished? [There is no suitable food for them or mothers do not prepare proper food.]
2. Do a class or community experiment on this for one to five year old children and then record a graph to compare malnutrition rates.

6.14.1 Child with diarrhoea, Shakir test
1. Be able to take care of younger children with diarrhoea by replacing water lost because of dehydration.
(in many areas, diarrhoea is the most common cause of death in small children, and is specially frequent in babies between six months and two years. It is more common and dangerous in children who are malnourished. Bottle fed babies have diarrhoea more often than breast fed babies. Diarrhoea can be prevented by: breast feeding babies for as long as possible, good nutrition and cleanliness. If you are a good teacher, you can teach your children how to care for younger children with diarrhoea. Use sugar, salt, water, spoons, cups.
2. How to give the drink, coconut water or "special drink": Start giving the drink when diarrhoea begins. A child should drink for each time a stool is passed. If the child vomits up the drink, keep giving more. A little of it will stay in the stomach. Give it in sips every two or three minutes. If the child does not want to drink, gently insist that the child tries to drink something. Keep giving the drink every two or three minutes, day and night until the child urinates normally, every two or three hours. Older children and their mother can take turns through the night.
Warning signs: Take the child with diarrhoea to the Health Centre if the child shows any signs of dehydration, cannot drink or will not drink, makes no urine for six hours, has diarrhoea too often so cannot drink one glass per stool, has blood in the stool, diarrhoea lasts more than two days.
3. Diarrhoea means frequent watery stools. Often children with diarrhoea also have vomited and have a swollen belly with cramps. The stools smell different from normal stools (toilet).
4. Children die of diarrhoea usually because their bodies lose too much water. This loss of water is called dehydration. All living things contain much water. For example, if you bring two cut plants to school, and put one in water and the other not, you will see that one will wilt. A baby with diarrhoea loses water like the wilted plant.
5. Signs of dehydration: 5.1 almost no urine that is dark yellow, 5.2 dry mouth, 5.3 sunken tearless eyes, 5.4 sunken soft spot (fontanelle) on top of baby's head, 5.5 skin loses its stretching. If you lift up the skin and you can still see the fold after you let go, the child is dehydrated.
6. The most important part of treatment is to replace the water lost through diarrhoea and vomiting. Medicines are often not very effective but coconut water puts water back into the child. Also children with diarrhoea must be given food, if they can take it, to help their bodies fight the sickness. 5. The Special Drink: Make the Special Drink from sugar, salt and water. Mix: sugar + salt + water. Use one level teaspoon of sugar and add a little salt at the end of the spoon in one glass of water. Before giving the drink taste it, it should be no more salty then tears. Let the children make the Special Drink and taste it.
Extra Activity: Visit a Health Centre to see how children are treated for diarrhoea and dehydration.

6.15 How far you can see?
Be able to test their eyes to find out if they can see things near and far.
Use Various objects, e.g. books, windows, trees
In the human eye the distance between the lens and the screen [the retina.] remains the same whether you try to see things near or far. What changes is the shape of the lens controlled by muscles in your eye.
1. Look outside the classroom at something far away. Hold up one finger 20 cm in front of your eyes but keep looking at the distant object. Can you see the distant object clearly? [Yes.] Can you see your finger clearly? [Not at first.] Can you feel any movement in your eyes? [Yes.] Is the distant object clear now that the finger is clear? [If you keep looking at your finger then the distant object will not be clear.]
2. Hold a printed page at arms length. Bring the book closer and closer until it is just too close to read the letters. Measure the distance from the book to the eyes with a ruler and record it in your notebook. Move the book away from the eyes until it is just too far to read the letters. Measure the distance and record.
3. Compare the distance recorded with other children. Are they all the same? [No, the answers should vary.]
4. Judging distance game
One child of each pair puts a hand over one eye. The other child holds up one finger about 40 cm in front of the partner's eyes. The child with one eye covered has to place the tip of one fingers on top of the finger that the partner is holding up. [This is difficult to do because you need both eyes to judge distances.] Uncover your eyes and try again. [It should be easy for them with both eyes open.] Partners swap places and repeat the activity. What conclusion? [We need both eyes to judge distance correctly.]

6.16 Measure air breathed out
See diagram 20.3.0:
Be able to measure how much air breathed out by displacement or water.
Use Marked jars, each group should have at least three jars, buckets, basins or any pool of water, lengths of rubber hose or hollow pawpaw sticks. Each child will probably need three jars to measure how much air in the lung.
The children take turns using the jars. Do the activity outside because water will be spilt. Take a deep breath. Blow air out slowly into one jar until all the water has been pushed out. Transfer to the next jar and blow more air out until your lungs are empty. You may need a third jar. The volume of the air in this person's lung is 1 000 cm³ + 1 000 cm³ + 200 cm³ = 2 200 cm³. The children will need help adding up how much air in each jar.
1. How can you make air replace water? [We did before by blowing air into upside down jars filled with water.] This time you will measure the volume of the lungs by measuring the volume of water the air pushed out.
2. Use one group to show the rest of the class how to fill the bottles of water, blow into the jar and refill with water. How much air breathed out is about equal to how much air is in the lungs.
3. Let each child to try to find out how much air in the lungs.
4. Draw a table of results on the chalk board. Which child has the largest volume of air in the lungs?
Be careful! Do not let children blow hard and do not make them blow if they feel sick!

6.17 Measure relative humidity
See diagram 8.10: Wet and dry bulb hygrometer | 37.8.4 Relative humidity table, depression of the wet bulb
Be able to explain the importance of humidity in your climate.
Use Figures of humidity measurements, thermometer and a piece of cloth.
Humidity is a measure of how much water vapour in the air. More water vapour can be in the air at higher temperatures than at lower temperatures, so if the temperature drops the water vapour will condense as rain. The relative humidity used in weather forecasting is a measure of how much water vapour held in the air compared with the amount it could hold. In the Solomon Islands humidity is always high. It does not change much during the year but it varies during the day. Relative humidity %

Month Time	Auki	Munda		Honiara		Kira Kira
June 9 a.m.	91	92	-	87	-	93
June 3 p.m.	77	75	-	70	-	77
Dec. 9 a.m.	85	85	-	83	-	90
Dec. 3 p.m.	75	75	-	73	-	77

At night the relative humidity is always greater then 90%. The lowest relative humidity occurs during the hottest times of the year. Children should understand that the climate of the Solomon Islands is hot and humid whereas in some places such as Western Australia and California it is hot dry. In Honiara there is the biggest change in relative humidity because the winds usually shift from southerly in the early mornings to northerly in the afternoon. You will need a bottle and running water. You can make a wet bulb thermometer with a thermometer and a piece of cloth.
1. Hold a bottle under a running tap and breathe into the bottle. What do you see? [The inside becomes cloudy.] What is inside the bottle? [Water.] Where did it come from? [Our lungs and the air.]
2. What do you see inside the walls of a freezer? [Ice.] Where does the ice come from? [It comes from the water in the air.]
3. Air can hold water in it as a gas. This gas is called water vapour. How much water in the air is called the humidity. The climate of the Solomon Islands is always humid compared with many other countries. The humidity is high because the country is near the equator and so the climate is hot. The winds come from over the sea picking up water.
4. If humidity is high, metal rusts easily, fungus diseases can live in the air and people feel hot because they cannot cool down so much by sweating. So remember that there may be problems with imported machines or seeds if they come from countries where humidity is low.
Extra Activity: Cover the bulb of a thermometer with cloth and dip this in water. The temperature should drop. The greater the drop in temperature the lower the humidity. The instrument used to measure relative humidity is a hygrometer. The hygrometer described in the activity uses two thermometers, a dry bulb thermometer and a wet bulb thermometer. The dry bulb thermometer is simply an ordinary mercury or spirit thermometer used to measure the temperature of the air. The wet bulb thermometer has the bulb is covered with cloth kept moist by means of a cotton wick and a glass of water. Evaporation cools the bulb and makes the reading lower than the dry bulb thermometer. The two thermometers are used in conjunction by means of tables to find relative humidity. The higher the humidity, the greater the difference in temperature between the two thermometers.