year6

School Science Lessons
Primary Science Lessons Year 6
2012-04-20a SPP
Please send comments to: J.Elfick@uq.edu.au
Suggested answers to the teacher's questions are shown within [square brackets].

Table of contents
6.1 Food chains in the forest
6.2 Protect turtles
6.3 Chicken life cycle
6.4 Pig life cycle
6.5 Fungi, Different fungi
6.6.0 Bacteria, Different bacteria
6.8 Heated liquids expand
6.9 Water climbs up
6.10 Pull with pulleys
6.11 Coins on a slope
6.12 Float clay boats
6.13 Forces of friction
6.14 Shakir strip, (Test for malnourished child)
6.15 How far you can see
6.16 Volume of air breathed out
6.17 Relative humidity
6.18 Atmospheric pressure
6.19 Moon and tides
6.20 Southern Cross constellation
6.21 Estimating
6.22 Pendulum tells the time
6.23 Trees and shrubs
6.24 Trees, palms and ferns
6.25 Protect trees
6.26 Grasses
6.27 Palms
6.28 Ferns and mosses
6.29 Protect coral reefs
6.30 Protect soils
6.31 Describe soils
6.32 Soil texture
6.33 Fertilizing soil
6.34a Chemical fertilizers
6.35 Burn candle over water
6.36 Cooling candle wax
6.37 Electric circuit
6.38 Electricity conductors
32.4.6.2 Electric torch, flashlight (See 1.)
6.40 Hanging magnets
6.41 Electromagnets
4.2.1 Prepare yoghurt
4.2.2 Prepare sauerkraut

6.1 Food chains in the forest
See diagram 9.311: Food chain animals
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 flow.
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 turtles
See diagram 9.307: Turtle
Be able to explain why we 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 we 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. We 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 we 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.
5. Explain how they can protect turtles:
1. protect eggs and hatched baby turtles,
2. protect laying mothers,
3. protect turtles at sea.
6. Show pictures of crocodile. What do they think of it? Do they want to kill it? Do they want to
protect it?
7. Explain why they should not kill crocodiles: 1. also part of natural heritage, 2. interesting
animals, 3. can be farmed.
8. Explain that we 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.

6.8 Heated liquids expand
See diagram 20.1.2: Heated liquids expand | See diagram 20.1.3: Heat from hands expands liquids
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
See diagram 35.6.1:
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 chalkboard. 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, fixed pulley, moveable pulley
Be able to use pulleys to change the direction of a pull and to move heavy loads.
Use pieces of string three metres 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 chalkboard 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 chalkboard 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 Coins on a slope
See diagram 16.160: Start and stop | See diagram 16.4.0: 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.]
5. 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.]
6. 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.
7. 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.
8. 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 Float clay boats
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 17.264: Reduce friction with ball bearings
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 chalkboard. 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?

6.17 Relative humidity
See diagram 37.114: Wet and dry bulb thermometer
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 per cent

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.

6.18 Atmospheric pressure
See diagram 12.272: Spurting tennis ball | See diagram 12.307: Mercury barometer
Be able to state how atmospheric pressure (air pressure) affects weather.
Use Coins, glasses of water with cardboard lids, drinking straws or tubing.
If you have a simple barometer or aneroid barometer you can use it in the lesson.
The average mean sea level pressures for example at Honiara in millibars (mb) are as follows:

June	9 a.m.	1 010.7 mb	3 p.m.	1008.8 mb
December	9 a.m.	1 007.9 mb	3 p.m.	1006.2 mb

1. Give each group a coin. Wet one side and then press it on the forehead. Why does the coin not fall
down? [The air presses it against the forehead.]
2. Give each group a glass full of water covered with a cardboard lid. Turn it upside down. Why does
the water stay in the glass? [The air presses the cardboard against the water.] In which direction does
the air press? [The air presses in all directions.]
3. Give each group a straw or tube and a glass of water. Suck on the straw until the water is half way
up it. Why does the water go up the tube? [When you suck in some air, the air pressure in the straw
becomes less. Then the air pressing on the water in the glass pushes some water up the straw.] Put your
first finger over the top of the straw and hold up the straw. Why does the water stay in the straw?
[The air is pressing up.]
4. Explain that air pressure can change. Air pressure is greatest at sea level and gets less with height. Air
pressure can also change at one place. When the air pressure is fine, the weather will stay fine. When
the air pressure is low, rain clouds will come and there will be wet weather. Very low air pressure occurs
before a cyclone.
5. Air pressure is measured with a barometer. This is a tube closed at one end. The other end is open in a
bowl of mercury. Mercury is a very heavy liquid. When the air pressure is high, the mercury is pushed high
up the tube. When the air pressure is low, the mercury is lower in the tube. On a fine day at sea level the
atmospheric pressure is 760 mm of mercury.
Extra Activity: Read a barometer every day. Note when is the pressure high and when is the pressure low.
Make a table to show some daily records of air pressure at 9.00 a.m.

6.19 Moon and tides
See diagram 36.28.1: Phases of the moon in a classroom
Be able to observe the moon and tides and try to find a connection between their movements.
Use Custom stories and observed movements of the moon.
This activity consists of three parts: custom stories about the moon and tides, movements of tides,
movements of the moon. There are many interesting stories about the moon. Some people see a
woman weaving baskets in it. Some people think it is a friend of Haley's comet, which reappears every
76 years, called the smoking star. The palolo worm which is a swimming annelid worm, rises to the
surface on the second night after the full moon in November. Then they mate and lay their eggs. Try
to find out the times for high and low tide and the phase of the moon.
1. When do you get high tides and low tides during the day? [There are two high tides and two low
tides each day about 12 hours apart.]
2. Are the heights of the high tide and low tide always the same during the month? [No.]
3. Are the heights of the high tide and low tide the same during the year? [No.]
4. What else changes during the month? [The moon.] How does it change? [First there is a new moon
when you can hardly see it then it gets bigger until a full moon, then it gets smaller.] How many days
between full moon? [30.] How many days in a month? [About 30.]
5. Can you see any connection between the moon and the tides?
6. Can you remember any custom stories about the moon and the tides?
Extra Activity: Wall chart on the phases of the moon. Rule the chart into squares and number the
squares with the dates of the month. Each evening a different child has to look for the moon then draw
it on the chart the next day. Wall chart on the tides, tide during the day. Measure the depth of the tide
each hour and mark on the wall chart. Measure the highest tide and lowest tide each day and mark
on the wall chart.
The Sun force is about 5 / 11 of the Moon force on the earth but they can act conjointly. When a
high tide occurs on one side of the Earth a high tide occurs on the other side of the Earth. Spring tides
are higher than other tides and occur just after new Moon and full Moon when the gravitational
attraction of both the Sun and the Moon act in a direct line. Spring tides are nothing to do with the
spring season. They "spring up" higher than the other tides. When the Moon is at first quarter or third
quarter, the tide is minimum, has the least rise and fall, and is called the neap tides The rise and fall of
the neap tides is about half that of the spring tides.

6.20 Southern Cross constellation
See diagram 36.73: Southern Cross constellation
Be able to observe the movement of stars in the Southern Cross constellation.
Use Evening and night observations of the stars in the Southern Cross and custom stories about it.
Make sure you can find the Southern Cross and pointers. When you have done that, you can show
the position of this constellation to children who will do their observations at night.
1. Draw the Southern Cross constellation and pointers on the chalk board and show the children in what
part of the sky these stars can be seen.
2. Look for these stars that evening. The next day, make sure that you really did see the Southern Cross.
Then tell the children to observe it the next evening at three different times: 6:00 p.m., 7:00 p.m. and
8:00 p.m. Draw it and another object such as a tree at these times.
3. The next day, look at their drawings. Do you realize that the Southern Cross and all stars appear to
move in a circle to the right? This shows that the earth is turning.
4. Show the children how to find South by extending Gamma, Alpha Crusis × 3½, then dropping to the
earth.
Extra Activity: Do you know any traditional stories about the Southern Cross? Some people said that the
Southern Cross is a fishing net suspended on four poles and the pointers are two fishermen. Some people
said that the appearance of the Southern Cross in March told them to start planting yams.

6.21 Estimating
See diagram 2.6.21: Estimates
6.21.1 Estimate total number using volume
You will need a jar full of seeds, e.g. bean seeds
1. Fill a matchbox with seeds from your jar.
2. Count the number of seeds in the matchbox. Record the number (N1).
3. Find out how many matchboxes of seeds there are in the jar. Record the number (N2).
4. Multiply the number of seeds in the first matchbox by the number of samples (N1 × N2).
5. Record this estimate in the table.

6.21.2 Estimate total number using areas
1. Draw 10 squares as in the diagram
2. Pour seeds onto the paper to completely cover one square, one seed thick.
3. Count the number of seeds in this square (N1).
4. Continue to add seeds to the squares until you have used all the seeds in the jar.
Count how many squares you used. (N2)?
5. Multiply the number of seeds in the first square by the number of squares used (N1 × N2).
6. Record this estimate in the table.
Compare this estimate with the estimate for 1A. Are the estimates similar? Which estimate do you
think is best? If you have estimates from different groups in the class calculate the average estimate.

6.21.3 Estimate total number using divided samples
You need 5 glass jars of the same size.
1. The first jar is full of seeds.
2. Pour seeds from the first jar into a second jar. Each jar contains half the seeds. Each jar contains
an equal number of seeds.
3. Pour seeds from the second jar into a third jar. The second and third jar contain the same amount
of seeds. They now contain a quarter of the original volume of seeds.
4. Repeat this procedure twice. The final set of jars is as in the diagram. The sample is contained in
jar number 5. Count the number of seeds in jar number 5. It contains 1/16 of the total. Multiply the
number of seeds in jar number 5 by 16.
6. Record this estimate in a table.
7. Count the number of seeds in the first jar by counting out the seeds in piles of ten. Record your
actual number in a table. Which of your estimates was closest to the actual number of seeds?

6.21.4 Estimate total number using layers
Use a full box of matches but do not count them. Open the box. Count the number of matches you can
see on in the top layer. Count the number of layers in the box. If you assume the same number of
matches in each layer, you can estimate the number of matches in the matchbox. Use this method to
estimate the number of seeds in the jar. Can you use this method to estimate: 1. The number of bricks
used to build your classroom 2. The number of sticks of chalk in a box 3. the number of words on a page
of a school textbook?

6.21.5 Estimate lengths using your body
Use a ruler to measure in centimetres these parts of your body:
1. The top joint of your thumb.
2. The length of your forefinger.
3. The span of your hand (see diagram).
4. The distance between the thumb and the nose when your arm is outstretched.
This is for measuring cloth or rope.
These parts of your body can all be used for measuring short lengths, e.g. the length of your desk,
or the height of a plant. Which distance would you use to plant seeds about 15 to 20 cm apart?
For distances on the ground you can use the length of your foot, or the length of a stride. Measure
the length of a normal walking stride. Use it to estimate the length of a football pitch. Mark out
distances of one metre along a straight line. Walk along this line. Make each stride one metre long.
Remember what it feels like. Use it to estimate the length of a football pitch. Then measure the
football pitch. Which of your two estimates is best?

6.21.6 Estimate heights
Estimate the height of a flag pole or a tree. You need a stick, or a ruler, and a stone.
1. You and your friend should stand on lines at right angles to each other as shown in diagram 1.
2. Hold your ruler in front of you and move either forwards or backwards until it appears to be the
same size as the flagpole (diagram 2). The bottom of the ruler should be in line with the bottom of the
flagpole. The top of the ruler should be in line with the top.
3. Do not move your hands. Let the ruler turn until it is horizontal (diagram 3). The left end of the ruler
is still in line with the base of the flag pole. Ask your friend to put a stone on the ground where it is in
line with the end of the ruler.
4. Measure the distance between the stone and the flag pole. This is a good estimate of the height of
the pole.

6.21.7 Estimate area of a leaf
The areas of squares and rectangles can be measured so you can use these to estimate other areas,
e.g. the area of a leaf.

6.21.8 Estimate area of a mouse
Rectangles of paper could be used to estimate the body area of animals, e.g. The body area of a mouse.
Use this method for estimating the area of your skin. You will need lots of newspaper, pins, scissors
and a ruler.

6.21.9 Estimate weight
Lift one kilogram. Feel the weight. Lift different things, e.g. bag of potatoes, house brick, bucket of water,
school bag, your friend. Can you estimate their weight in kilograms?
Know the feel of these weights:
10 grams = the weight of 4 drink bottle tops
1 kilogram = the weight of 1 litre of water
10 kilograms = the weight of 10 litres of water.
Use a balance to estimate the weight of small objects of the same size, e.g. pins and paper clips.
Useful ways to measure and approximate size
1 teaspoon (the smallest spoon) 4.5 mL
1 dessertspoon (the spoon you eat with) 10 mL
1 teacup (the cup you use with a saucer) 200 mL
1 matchbox volume 25 mL
Area of the top of a matchbox 20 cm²
1 gallon container holds 5 L
1 fluid ounce container holds 30 mL
Human body temperature 37^oC (Celsius)
Weights of one matchbox full of fertilizer
Ammonium sulfate (sulfate of ammonia) 26 g
Potassium chloride (muriate of potash) 24 g
Single superphosphate, "super" 22 g
Triple superphosphate, "super" 20 g
Sulfur 20 gm

6.22 Pendulum tells the time
See diagram 15.1.1: Pendulum technical diagram
Be able to observe the effect of changing: the swing, length, and weight of a pendulum on the time
taken for each swing.
Use string, a pendulum bob, stop watch or watch with second hand. Set up a pendulum so that you can
change the length of the string and weight of the bob.
Set up the pendulum as in the diagram. The distance from the knot to the centre of the bob should be
exactly one metre. The time for one complete swing is the time between movements over the arrow in
the same direction. Pull the bob a few centimetres to the side then let go. Then try with a big swing.
Then try with a shorter swing. Then try with a one metre swing and heavier bob.
The time for a swing is the time for the pendulum bob to go forwards, then backwards to where it
started.
Fill in the table, for example:

Length	Weight	Size of swing	Time for one swing
1.0 m	1.0 kg	big swing	2 seconds
1.0 m	0.5 kg	big swing	2 seconds
1.0 m	0.5 kg	small swing	2 seconds
0.5 m	0.5 kg	big swing	about 14 seconds
0.5 m	0.5 kg	small swing	about 14 seconds
1.5 m	0.5 kg	big swing	about 25 seconds
1.5 m	0.5 kg	small swing	about 25 seconds

Extra Activity: Watch a swinging pendulum very closely. Where does it move fastest? [In the middle
of the swing when the bob is passing the arrow.] When does it move slowest? [At the end of each
swing when it stops then changes direction.]
Another way to measure time is to use clean sand in a double v-shaped container, e.g. an egg timer
Commercial
Timer, three minute, sand hourglass /egg timer

6.23 Trees and shrubs
See diagram 9.53.9: Trees
Be able to identify and describe some trees, shrubs and herbs in the locality.
Use local examples of herbs, shrubs and trees, plant presses.
The plants you know as trees, shrubs and herbs or bushy plants have the parts of their flowers in fives,
leaves shaped like hands with three parts, a tap root, and the trees and shrubs are woody. Trees are
tall with usually one main stem. Shrubs are smaller and branch near the ground. Trees include the
mango tree, cassia trees, Acacia, Casuarina or she oak and Ngali Nut tree. Shrubs include Euphorbia,
Hibiscus, side herbs include most weeds, e.g. Commelina.
1. Explain the difference between trees, shrubs and herbs and show the children some examples.
[See the differences above.]
2. Look at a herb. Does it have a stem? [Yes.] What is the shape of the leaf? [Like a hand.]
What kind of root does it have? [A tap root and smaller roots.] Does it have flowers? [Yes.]
3. List all the trees, shrubs and herbs you know. They may have to stroll around the area.
4. Some herbs are thin stemmed vines, some are called climbers, e.g. passion fruit (Granadilla) and
Bougainvillaea. Some are creepers, e.g. Basella (Indian Spinach.)
5. Garden Walk
See the trees, shrubs and herbs.
Extra Activity: Display of cut out shapes of trees, shrubs and herbs. Hold a piece of paper up and
draw the shape of the tree on it. Cut it out and stick it on the display board. Can you tell a tree by its
shape? You could also display herbarium specimens of various trees, shrubs and herbs. Can you
identify the specimens?

6.24 Trees, palms and ferns
Be able to identify some trees, palms and ferns.
See Plants, Common names first
See diagram 9.48.2: Bracken Fern | See diagram 9.50.2: Palm tree |
See diagram 9.50.3: Pandanus palm | See diagram 53.2: Coconut palms
See diagram 9.50: Pine tree cone (Conifer)
1. Show the children samples of trees, palms and ferns. What is the main difference?
[The shapes of the leaves.]
2. Draw some leaves of each, e.g. cocoa leaf, palm leaf, fern leaf.
3. Which trees, palms and ferns can they name? What are the uses of these plants?
4. List all the trees, palms and ferns they know.
Extra Activity: Naming Game.
Take the children for a walk. What are the names of the trees, palms or ferns seen during the walk?
Sentence completion: The three main kinds of large plants are as follows: 1. [Trees, e.g. Breadfruit,
Leucaena] 2. [Palms, e.g. Coconut] 3. [Ferns, e.g. Takuma].
Extra Activity: Collect the following stages of a known tree, e.g. mango or Terminalia, seed, young
plant, plant with flowers and fruit.

6.25 Protect trees
See diagram 9.53.9: Conserving trees
Be able to state why we should carefully protect your bush trees.
Use Trees are part of out natural heritage. We should make sure that all the different kinds of trees in
your forests will be there in the future for the next generations. Forest trees have survived for thousands
of years so why should you worry about them now? The population is increasing rapidly so there are
now more people who want to use the products of the forest. Trees can be cut down easily by modern
equipment such as chain saws. Logging of a forest has the result that all the largest trees are cut out.
They may grow again. Cutting down a forest for wood chipping means that all trees are cut down and
the same type of forest may never grow there again. Burning off grass lands kills any small trees.
1. Explain the importance of the forest. It is not just the bush. It has been a source of benefit for the people
for a long time. Divide the class into groups. Each group must list the benefits to the people of the forest.
Read out their list. Summarize the benefits on the chalkboard.
2. List the names of bush trees that benefit people, e.g. cotton tree for stuffing pillows, Kamarere for timber
and fuel wood, local nutmeg for eating.
3. Why we should not burn grassland? [The small tree seedling cannot grow and so the forest shrinks.]
4. What can you do to tell other people to conserve your trees?
Extra Activity: Talk from a forestry officer. The teacher should have previously informed the officer ahead
of time for this exercise.

6.26 Grasses
See diagram 9.52: Monocotyledon. grass
Be able to 1. describe and identify the parts of grass and how they grow and 2. distinguish between
grasses and sedges.
Use Grasses are the most useful group of plants. They have many small flowers and, except bamboo,
grow close to the ground as runners or tufts. They have a special shape of leaf. Each leaf has a leaf
blade, sheath and a ligule. They have parallel veins. Sedges have angular stems while grasses have
round stems.
1. Give each group different kinds of grass. What do you call these plants? [Grass.] How are they
different? [Tufted grass grows upright in a clump, rumour grass grows along the ground, bamboo
is very tall and has a woody stem, cereals have large grains that you can eat.]
2. Look at the tufted grass and runner grass. How are the grasses different from bushes and trees?
[Grasses are small plants, they may cover the ground, they have very small flowers and seeds, cereals
produce grains. They have fibrous roots.]
3. Describe the grass roots. [Lots of small roots that grow from the same place, bushes and trees have
a long tap root and smaller roots from growing along it.]
4. Describe the grass stem. [Most grasses have no stem, cereals and bamboo have a kind of stem that
may be hollow.]
5. Describe the grass leaves. [The leaves are quite different from the leaves of bushes and trees, grass
leaves are long and thin, part of them wraps around the other leaves or stem and part hangs down
when it is old.]
6. Can you see the grass flowers? They are very small. Large grass seeds are called grain.
7. Pull off a while grass leaf and draw it.
(8) Pull off a sedge stem and compare with a grass stem.
Extra Activity: Drawings of grass plants.

6.27 Palms
See diagram 9.50.2: Palms
Be able to describe different palms and how they grow.
Use examples or pictures of palm plants, mosses and ferns. Edible palms include coconut, sago, oil
and date palms.
1. Give each group a piece of palm leaf. What kind of plant is it from? [Palm.] How is it different
from the fern or moss leaf? [It is much bigger, hard and shiny, divided into strips.]
2. How many useful palms do you know? [Coconut, sago, raphia, nipa, betel, oil palm, pandanus.]
Do you know a useful palm that grows in the desert? [date palm.] There are many other kinds of palms
in the forest. Do you know any use for them?
3. Show the children a picture of a palm tree or show them a palm outside.
What do you notice about the following parts of a palm?
The stem [It grows straight up, no branches.]
How the leaves grow [The leaves grow from the top of the stem, the youngest at the tip, the oldest
hang down.]
The size of the leaves [The leaves are very big.]
The shape of the leaves [Split into strips or fan-shaped.]
The roots [Shallow roots that may stick out before going into the ground.]
The fruit [They can be large and heavy.]
4. Palms are one of the most useful plants in the world. Palms are also special trees in the forest.
They grow very slowly so we should not cut them down unless you have a good reason. Be kind to palms.
Extra Activity: Visit the forest and study the sago palm. Before it flowers, you cut it down and wash the sago
starch out of its trunk. The leaves make good palm thatch.

6.28 Ferns and mosses
See diagram 9.48.2: Pteridium bracken fern | See diagram 9.47.3: Dawsonia moss
Be able to collect and describe different ferns and mosses.
Use different types of ferns and mosses:
1. tiny, filmy ferns 2. bracken ferns that grew up out of the ground 3. tree ferns that are tall and have
a kind of trunk 4. epiphytic ferns that grow high up on other plants and grow high up on other plants
to reach the light 5. magnifiers.
Ferns do not have flowers, seeds or fruits. They reproduce by tiny round spores from the underside of
their leaves called fronds. If they press a frond down on to inked paper, you can get an outline of where
the spores are made. Ferns usually live in damp places or in the forest. Mosses are tiny single plants that
crowd together like the pile of a carpet. Ferns are found in damp places. They have root-like structures
called rhizoids Use ferns to the lesson or prepare to go out to the forest to see different kinds of ferns.
Collect ferns with brown spores underneath. The spores underneath are called sori, singular "sorus".
They are used for reproduction.
1. Show the class the different kinds of ferns and mosses. Have you seen them before? Can ferns be
poisonous? [Yes, some ferns can make cattle sick if they eat them.]
2. What do you see on the fern leaf (frond)? [Brown balls are under the frond.] They are called spores
or sori and are like little seeds. They are used for reproduction.
3. Draw a fern leaf. How is it different from the leaf of a tree? [It is much thinner and has a different
shape.]
4. Does it have flowers and fruits? [No.] Does it have a stem? [Some have a kind of stem.] Does it
have a tap root? [No, it has little roots.]
5. Look at a piece of moss carpet. Can you see the separate moss plants standing up straight? Can you
separate one moss plant? Why do they all stand closely together? [To keep water between them and
not get dry.] Look at a single moss plant with the magnifier. Does it have flowers? [No.] Does it have
leaves, stem and root? [Yes, but they are very small and simple.]
Extra Activity: Make spore outlines on inked paper, or draw a harvested sample from a moss plant.
Use the magnifier for the initial observation.

6.29 Protect coral reefs
See diagram 4.62: Conserving land
Be able to explain why we should stop loss of land and coral reefs by controlling water runoff.
Use Examples of ridges and terraces.
If land is perfectly flat it cannot be washed away by rain, but it may be cut away by a river. Heavy rain
can cause loss of nutrients by leaching. Sloping land can be washed away if water washes over it. Loss
of land can be prevented by covering the soil with grass and trees. When people make gardens on
slopes some soil will be washed into the valley below to become valuable topsoil. However, that
topsoil will be lost if it is washed into the river and becomes silt. The silt can cover the animals in the
coral reef and kill them. Children should know how to prevent loss of land and coral reefs.
1. What will happen to the bare soil on slopes if it rains? [It is washed down.] Where does it go? [On
to the land below.] Where can it go? [Into the river.] Where does the silt go? [Out to sea, it can cover
the coral.]
2. How can you stop water washing the soil down? [1. Grow crops in horizontal strips 2. Build terraces
to hold the soil back 3. Dig horizontal ridges 4. Dig drains to carry water away.]
3. What is the best way to protect a sloping level? [Cover with plants.]
Extra Activity: Visit to ridges and terraces.

6.30 Protect soils
See diagram 4.62: Strip cropping
Be able to explain why you must change the traditional methods of gardening and burn less bush.
Use Traditional gardening environment, modern improvement methods showed and explained by
agricultural officers.
This lesson is not designed to teach children that the traditional methods of gardening were wrong.
They were excellent methods because they allowed soil fertility to be restored by the forest and
efficiently used the garden land by having a variety of sized food plants growing in the gardens.
They provided enough food for the people. The system should be changed now because of the growth
of population. However, we should try to improve the traditional methods.
1. Describe their traditional method of shifting cultivation.
2. Explain that the hot wet climate of the Solomon Islands helps all plants to grow very quickly.
The result is that in traditional gardening you cannot use the garden for more than a few years
because the fast growing weeds take over.
3. Another reason that people shift a garden is that the crops take out nutrients from the soil, especially
potash and phosphorus and so the soils become less fertile. 4. The traditional method was to let the
forest grow back over the garden land and not use it again for 15 to 20 years. This is called the bush
fallow system. During this time the rotting leaves from the forest would restore the soil fertility.
5. However, now the population is increasing rapidly and the people are moving to towns. There is not
enough land to allow the long fallow periods so people are using the land again for gardens before soil
fertility is restored. Forest is changing to grassland and soil is being washed away.
6. Agricultural officers believe that one way to conserve soil fertility would be less burning of cleared
land. Burning of loose leaves and sticks returns some nutrient to the soil in the ash and it also kills some
diseases and weed seeds. However, some plant nutrients are lost in the smoke. Much ash is washed
away, the bare ground is eroded by heavy rain and plant nutrients can be washed away or leached.
7. The best method is to cut the trees low but not harm the stumps so that they can grow again easily.
This is called secondary forest regeneration. Burn the wood and trash that get in the way but use the
leaves for mulch.
Extra Activity: Visit a traditional garden to see how the cut bush is burned.

6.31 Soils, Describe soils
See diagram 6.36.3: Examining soils
Be able to link different types of soils with their physical properties.
Use A large container of garden soil, different kinds of soils, e.g. sand, clay, swamp, magnifiers, sheets
of paper (the different soils should be placed on these), glass jars, buckets of water, table of results.
Examine soil types with special reference to the texture types.
1. Give soil samples and other materials to each group. Label each soil sample Put garden soil in the
glass jar, until it is about one third full of soil. Pour water from the bucket into the jar containing the
soil until the jar is two thirds full. Put the lid on the jar and shake strongly, watch what happens inside
the jar for a few minutes. [Solid particles settle to the bottom.]
2. What do you see from top to bottom in the jar? [Floating plant matter, clay suspended in the water,
fine sand, coarse sand, pebbles.] Put this jar where it will not be moved as they will be looking at it
later in the lesson.
3. Take each sample of soil (including garden soil) and feel and look at each closely with the magnifier
to see: the colour, the way the soil holds together, the size of the particles, how much water there is in
the soil, how much plant matter there is in the soil, if any animals are present, the feel of the soil.
4. Complete their table of results.
Extra Activity: Use another soil sample from home for further testing.
Table of Results
Which soil has the darkest colour? [Swampy soil.] Which soil feels the most sticky? [Swampy soil.]
Which soil feels the driest? [Sandy soil.] Which soil is held together most loosely? [Sandy soil.]
Which soil has the most plant matter? [Garden soil or swamp soil.]

6.32 Soil texture
Be able to show a simple method of determining the texture of soil.
Use samples of different soils, e.g. clay, silt, sand and a small quantity of water.
The texture of a soil affects soil characteristics such as ease of cultivation, its ability to accept water
and how much water it can hold for plants and other organisms to use. A quick and simple technique
to measure soil texture is useful when deciding agricultural activities such as ploughing.
Soil texture reference information:
1. Sands have grains that do not stick together. Sands cannot be moulded. Single sand grains stick to
the fingers.
2. Loamy sands form fragile shapes that just stand handling, give short ribbons that break easily, usually
discolour the fingers.
3. Fine sandy loams form shapes that will just stand handling. Fine sand grains may be felt but otherwise
they feel smooth and may feel greasy if much organic matter is present. Fine sandy loams may be
formed into ribbons 15 to 25 mm long.
4. Silty loams will stick together but will crumble. Silty loams feel very smooth and silky and may be
formed into ribbons 25 mm long.
5. Clay loams will stick together to form shapes. Clay loams have a spongy feel and are plastic when
squeezed between the thumb and forefinger. They are smooth to manipulate and may be formed into
ribbons 40-80 mm long.
6, Clays form smooth, plastics casts and show some resistance to manipulation, i.e. toughness.
They may be formed into ribbons at least 80 mm long, depending on heaviness of the clay.
Sand grains can be felt in sandy clays that may be formed into ribbons 40-50 mm long.
1. Take a small amount of soil enough to fit in the palm of the hand. Discard obvious pieces of gravel.
2. Moisten the soil with water, a little at a time and knead until there is no apparent change in the feel
of the ball. The moisture constant should be such that the ball just fails to stick to the fingers.
3. Inspect the sample to see if sand is visible, if not, it may still be felt and kneaded as the sample
is worked.
5. Finally, squeeze it out between the thumb and forefinger with a sliding motion and note the length
of self supporting ribbon that can be formed.
6. Give the children some pure sand, silt and clay to test. Then test soil from 1. a garden 2. a forest
3. bank of a river 4. top of a slope.
Extra Activity: Texture museum. Try to collect samples of soil with the six types of texture. Keep
them in glass jars for reference.

6.35 Burn candle over water
See diagram 6.35: Burn candle over water
Be able to observe what happens when a candle burns.
Use glass jars, candles, tray, water, a ruler.
Practice this demonstration before the lesson.
Method 1:
1. Fix a candle to floating cork. Put some water in the tray so that the water level is about half the
length of the candle.
2. Measure the depth of the water in the bucket. Measure the length of the jar. The jar is full of air
so you are really measuring how much air in the jar. Light the candle.
3. Place the jar over the candle quickly so that the mouth of the jar is under water.
4. What do you see? [1. The candle flame gets smaller, splutters then goes out. 2. While the candle was
alight, some air bubbles came out from under the jar. 3. When the flame went out water rose in the jar
and the water level dropped slightly in the bucket. 4. Some water condensed inside the jar and on the
wick.]
5. Why did the candle flame go out? [Some of the oxygen was converted to carbon dioxide gas. The
blackened wick is carbon ]
6. Why did some air bubbles come out from under the jar? [The candle flame heated the air in the jar
causing the air to expand.]
7. Why did the water move up the jar? [When the candle flame went out the gases in the jar cooled and
contracted to a smaller volume than before so the air pressure in the jar was less than the atmospheric
pressure. The air pressure on the surface of the water in the bucket pushed the water up into the jar.]
Method 2: Repeat the experiment with one, two and three happy birthday cake candles
1. Fix the candles to Plasticine at the bottom of the tray then do the experiment as before
2. The air in the jar is less heated with smaller candles so you probably do not see bubbles coming out
from under the jar. The jars contained about the same amount of oxygen but the jar with the three
candles showed the greatest water rise because more heat was produced by the candles in it.
Extra Activity: Why does a candle burn? [When you light a candle wick, some heat from the burning
wick melts the wax at the top of the candle. The melted wax rises in the wick because of capillary
forces and some of that wax evaporates to form a vapour that rises then burns with a bright flame.]

6.36 Cooling candle wax
See diagram: 3.2.0.3 Speed of cooling
Be able to discover whether the speed of cooling affects the size of crystals and then to discuss why
rocks have different sizes of crystals.
Use small glass tubes, or any other glass container you can heat, burner, or a candle in a holder, a
wooden peg, two glass jars, naphthalene (moth balls) or crystals of copper (II) sulfate or salt or sugar,
silver foil or paper or cloth.
An igneous rock consists of crystals produced when the rock cooled from a very hot liquid state. Rocks
that formed deep in the ground such as granite have large crystals. Rock that formed on the ground after
the liquid rock came out of volcanoes, such as basalt, have small crystals. Rocks formed deep in the
ground cool slowly. Rocks formed above the ground cool quickly.
1. In this lesson you will imitate the cooling of an igneous rock.
2. Fill the two test-tubes with naphthalene to the one quarter mark, Using the wooden peg, gently heat the
test-tubes until the naphthalene starts to melt.
3. Move the test-tubes about to distribute heat evenly. Then remove the tubes from the flame and shake
gently. Heat a little more, then shake again. Keep doing this until all the naphthalene has melted, or
dissolve as many crystals as you can in a small amount of warm water.
4. Quickly wrap the test-tube containing the melted naphthalene or crystal in silver foil to keep it warm.
Then stand it in a large beaker.
5. Rapidly cool the second lot of melted naphthalene or dissolved crystals in a beaker of cold water.
6. Observe the naphthalene or dissolved crystals in the two tubes and note carefully the size of the
crystals formed. Why the crystals in the tubes are different sizes. [Larger crystals formed in the tube
wrapped in foil because it cooled more slowly than the tube in the cold water.]
7. What is the relationship between the rate of cooling and crystal size of igneous rocks? [The slower
the speed of cooling the larger the crystals formed.]
Extra Activity: Can you find rocks that cooled quickly?

Candle "lava"
Cooling candle wax looks like cooling lava, describe shapes
Be able to observe the shapes formed by falling drops of molten wax and discuss how molten rock cools.
Use candles, matches and a safe place to drop the wax.
Find time to do the activities recommended here.
1. Hold a lighted candle 30 cm above the tray to let drops of melted wax fall on it. BE CAREFUL!
2. Repeat this procedure several times, holding the candle at different heights. Observe the cooled drops.
3. From which height did the molten wax spatter the most? The least? What shape did the cooled wax take?
4. Explain that volcanoes sometimes shoot out molten rock called lava. Does this experiment explain the
cooled shapes of lava from a volcanic eruption?
Extra Activity: Study a volcano cone. Does the candle wax experiment help you understand how the
cone was formed?

6.37 Electric circuit
See diagram: 32.2.1: Simple electric circuit
Be able to set up an electric circuit to light a light bulb.
Use torch light batteries, wires, sticky tape, bulbs, bulb holders.
Electricity can only be generated if there is a complete circuit. Revise electric circuits before the lesson.
1. Give each group a battery, wires and a light bulb. You must need some sticky tape to hold the wires
on the bulb contacts. Do not show the children what to do. Light the bulb. Which group can do it first?
Can you tell the other groups how you did it? This is one way of encouraging the scientific attitude.
2. Look at the torch battery. What do you see at each end? [The top has a bump marked on it and is
marked "+", the bottom is marked "-". Each end is made of metal.] How did you make the bulb light?
[One wire touches one end of the battery. The other wire touches the other end of the battery.]
3. Look at the light bulb. What do you see inside the glass bulb? [A thin twisted wire called the filament.]
Is there a metal part? [Yes, below the glass part.] How did they make the bulb light up? [One wire
touches the bottom of the metal part, the other wire touches the side of the metal part.]
4. Electricity travels along a path. If the path is blocked, then electricity cannot keep flowing. The whole
path along which the electricity travels is called a circuit. A broken path is called an open circuit.
Extra Activity:
1. Break open an old torch battery with the back of an axe. Be careful!
Can you see the 1. cardboard cover, 2. zinc case,. 3. black chemical which is a sticky powder,
4. a black carbon rod down the centre of the battery?

6.38 Electricity conductors
See diagram: 32.2.1: Electricity conductor
Be able to use a test circuit to show which substances are conductors of electricity. Use Batteries,
bulb holders (not essential), pieces of wire (30 pieces if bulb holders are used), connecting boards,
many items for testing, e.g. nails, string, wood, plastic rulers, chalk, rubber, leaves.
1. Use the chalkboard diagram to show the children how to set up their testing circuits. Give out the
materials and tell them to set up their own circuits.
2. Trace the path of the electricity from one end of the battery to the other through the circuit. Is the
pathway complete? [No.] Does the bulb light? [No.] Put a piece of wire across the break between
the two drawing pins. What happens? [The bulb lights.] Why? [The wire completes the pathway and
allows the electricity to flow through the circuit.]
3. Test each item to see if they will allow electricity to flow by placing them to touch two drawing pins.
How will you know if electricity is flowing? [The light bulb glows.]
4. Divide the items into two groups. Group 1 contains things that electricity will flow through, conductors.
Group 2 contains things that electricity will not flow through, insulators. When all the groups have finished
, fill in the table of results on the chalkboard.
5. Most metals are good conductors of electricity, e.g. iron, tin, and copper are used to make wires. Most
non-metals do not conduct electricity, e.g. glass, plastic, clay, rubber, wood, air. They are called insulators
and are used to stop the flow of electricity. Can you see insulators on an electricity pole? [Yes.]
Extra Activity: List conductors and insulators you can see in a home/ town. Show the children the large white
insulators on electric power poles. Never touch power lines with sticks or the string of a kite. Sometimes
power poles will conduct electricity will conduct electricity if they are wet so the children should not touch them.
If you see power lines lying on the ground, we should tell people to keep away and inform local government.