earth and beyond [grade 7 english]

WESTERN CAPE PRIMARY SCIENCE PROGRAMME

EARTH AND BEYONDGrade 7

We welcome the wide use of these materials. Please acknowledge the PSP. © PSP 2001

A SHORT LEARNING PROGRAMME ON THE NATURALSCIENCES THEME:

ACTIVITIES1. What shape is

our Earth?2. Where on

Earth is theland, the waterand the air?

3. Finding outabout theEarth’satmosphere

4. Our Earth is aplanet

5. There are nineplanets aroundthe sun

6. The inside ofthe Earth

7. Finding outmore about ourhome planet (a) We have

volcanoes in our planet

(b) We need minerals from the Earth’s crust in our lives

Course presented by Rose Thomas and Sandra Mahote

Booklet designed by Welma Odendaal and illustrated by Janet Ranson and Nicci Cairns

Western Cape Primary Science ProgrammeEdith Stephens Wetland Park Lansdowne Road Philippi 7785

PO Box 529Howard Place7450

Tel: 021 691-9039 Fax: 021 691-6350

e-mail: [email protected]: www.psp.org.za

DEVELOPED BY WESTERN CAPE PSP TEAM AND TEACHERS

This learning programme will work towards the following learning outcomes in the Natural Sciences

s LO1: Scientific InvestigationsThe learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts

s LO2: Constructing Science KnowledgeThe learner will know and be able to interpret and apply scientific, technological andenvironmental knowledge

s LO3: Science, Society and the EnvironmentThe learner will be able to demonstrate an understanding of the interrelationships betweenscience and technology, society and the environment.

All images of the planetscourtesy of NASA.Our thanks to the SouthAfrican AstronomicalSociety for the information aboutthe planets.

Contents• This booklet illustrates an example of a short learning programme for Grade 7.

• It develops concepts, skills, attitudes and language in a step-wise fashion.

• It includes activities and tasks for learners, teacher tasks, support materials and

assessment suggestions.

1 . . . . . . . . . . . . . .Activity 1 What shape is our Earth?

2 . . . . . . . . . . . . . .Activity 2 Where on Earth is the land, the water and the air?

3 . . . . . . . . . . . . . .Activity 3 A. Finding out about the Earth’s atmosphere6 . . . . . . . . . . . . . . . . . . . . . . . . .B. The layers of the atmosphere8 . . . . . . . . . . . . . . . . . . . . . . . . .C. Our air is precious but we pollute it

11 . . . . . . . . . . . . .Activity 4 Our Earth is a planet

13 . . . . . . . . . . . . .Activity 5 There are nine planets around the sun

15 . . . . . . . . . . . . .Activity 6 The inside of the Earth15 . . . . . . . . . . . . . . . . . . . . . . . .A. The inside of the Earth is made up of layers16 . . . . . . . . . . . . . . . . . . . . . . . .B. A play dough model of the inside of the Earth17 . . . . . . . . . . . . . . . . . . . . . . . .C. How big is our Earth?

20 . . . . . . . . . . . . .Activity 7 Finding out more about our home planet20 . . . . . . . . . . . . . . . . . . . . . . . .A. We have volcanoes in our planet25 . . . . . . . . . . . . . . . . . . . . . . . .B. We need minerals from the Earth’s crust in our

lives

26 . . . . . . . . . . . . .Suggested work scheme for this learning programme Assessment and Recording Suggestions

27 . . . . . . . . . . . . .Assessment sheet for assessing a task

28 . . . . . . . . . . . . .Recording sheet for task assessment

29–30 . . . . . . . . . .Blank Assessment sheets

31 . . . . . . . . . . . . .Codes for Assessment

Support materials and task cards to photocopy

32 . . . . . . . . . . . . .Activity 2 Map of the world

34 . . . . . . . . . . . . .Activity 3 Readings about the Earth’s atmosphere35 . . . . . . . . . . . . . . . . . . . . . . . .Graph paper36 . . . . . . . . . . . . . . . . . . . . . . . .A. Air and living creatures

37 . . . . . . . . . . . . . . . . . . . . . . . .B. Layers of the atmosphere

38 . . . . . . . . . . . . . . . . . . . . . . . .C. What pollutes the air?

39 . . . . . . . . . . . . .Activity 4 Reading about planet Earth and the sun

40-43 . . . . . . . . . . .Activity 5 Set of “Nine Planets”

44 . . . . . . . . . . . . .The solar system chart

46 . . . . . . . . . . . . .Planet fact sheet

47 . . . . . . . . . . . . .Task card “The Solar System”

48 . . . . . . . . . . . . .Activity 6 Cut-away section drawing to show the inside structure of the Earth

48 . . . . . . . . . . . . .Reading about the Earth’s inside structure

49 . . . . . . . . . . . . .Play dough recipe

50 . . . . . . . . . . . . .Task card “Inside the Earth”

51 . . . . . . . . . . . . .Task card “How big is our Earth?”

52 . . . . . . . . . . . . .Activity 7 Reading about the Mount St. Helens volcanic eruption

57 . . . . . . . . . . . . .Readings about other volcanoes

58 . . . . . . . . . . . . .Diagram of a volcano

59 . . . . . . . . . . . . .A. Task card “Comparing a demonstration of a volcano and a real volcano”

60 . . . . . . . . . . . . .B. Task card “So many things come from the Earth’s crust”

62–63 . . . . . . . . . .Task card: What does ‘ling of kwaito’ Arthur Mofekate need?

64 . . . . . . . . . . . . .Mineral fact sheet

Cover . . . . . . . . . .Mind map of Earth and Beyond

1

What shape is our Earth?

Give learners a box with different shapes

Choose a shape which best resembles the shape of the Earth from theitems in the box and explain why you decided to choose that shape.

1. Find pictures in newspapers or old magazines to show evidence thatthe Earth is round.

2. Supply learners with newspaper, scrap sheets of white A4 paper, flourand water to make a model of the Earth.

Make a paper model of the Earth by following the steps below:1. Crumple 10 sheets of newspaper together to make a ball shape.2. Tear two or three sheets of white A4 paper into thin strips.3. Make a glue paste out of flour and water.4. Spread the glue onto the strips of white paper with your fingers.5. Bandage the strips around the ball of newspaper until the ball is

completely covered.6. Put your Earth paper model in the sun to dry.

• The Earth is round like a ball

Activity 11

Key concepts

Teacher task

Learner task

Learner task

Teacher task

2

Where on Earth is the land, the waterand the air ?

Give each group of learners a map of the world to cut out continents anda piece of pantihose to show how thin the Earth’s atmosphere is.

1. Draw the equator onto your Earth paper model and make a mark toshow where the North pole and the South pole are.

2. Cut out continents from the map of the world.

3. Paste them onto your Earth paper model. Use an atlas to help you put the continents more or less onto their correct positions.

4. Colour the land brown and colour the water blue.

5. Put on the air by stretching the pantihose over your Earth paper model.

1. Facilitate a discussion and make sure that the learners understand the following:A that most of our Earth is covered by water (nearly 70% of the

Earth’s surface), andA the atmosphere that covers the Earth is a very thin layer.

2. Use the following questions to help the discussion:A of which colour is there most on your model?A what does this tell you?

• The Earth has land, water and air• More than two thirds of the Earth’s surface is covered by water,

and nearly all of that water is in oceans• There is a very thin layer of atmosphere covering our Earth

Activity 22

Key concepts

Teacher task

Learner task

Teacher task

Pantihose coveringthe model of theEarth

Yes! It is because most of

the Earth iscovered in water.

Look! I’ve used up

my bluecrayon!

ActivityAAsssseessssmmeenntt 22 Where on Earth is the land water and the air?

What we want to assess What we expect from learners

Making the paper model a The model should be sphericalof the Earth a The equator should be drawn more or less in the correct position

i.e. the model should have almost 2 equal halves to represent the Southern Hemisphere and the Northern Hemisphere

a Position of the North pole and the South pole should be clearly marked on the model

a Land masses should be placed in more or less the correct position a Land should be coloured brown, the sea blue and the pantihose

should be stretched over the model to represent the thin atmosphere

3

Finding out about the Earth’satmosphere

A. The Earth’s atmosphere1. Explain the following to the learners:

A Around the Earth there is a very thin layer of gases called theatmosphere.

A The atmosphere is a mixture of gases that occur in certainproportions.

2. Also explain the pie chart below that shows what proportion of eachgas there is in the air.

3. Supply the learners with the reading about “The Earth’s atmosphere isa mixture of gases” (see page 34).

The Earth’s atmosphere is a mixture of gases

The air we breathe is a mixture of gases that surround the Earth in layers.Air keeps the Earth’s surface at just the right temperature to support life.These layers of air and other gases are also called the Earth’satmosphere.

• There is a very thin layer of gases around the Earth called the atmosphere

• The atmosphere is a mixture of gases (mainly Nitrogen, Oxygen and Carbon dioxide)

• These gases occur in certain proportions:Nitrogen 78%Oxygen 20%Carbon dioxide less than 1%Other gases 1%

• Air is essential for life

Activity 33

Key concepts

20% oxygen

1% argon andother rare gases

less than 1%carbon dioxide

78% nitrogen

that’s what webreathe!

all these gasesare mixedtogether

The air we breathe also contains the following:A Water vapourA Fumes called hydrocarbons, which come from car exhausts,

factories and firesA Dust particlesA Other gases, in very small amounts, for example, ozone, argon,

neon, helium and krypton.

Read the information about the Earth’s atmosphere and complete thetasks below:1. Draw a bar graph to show how much of each gas is in the air.

Learner task

Teacher task

2. Which gas makes up most of the air?

Air and living creatures and plantsSupply the learners with the reading “Air and living creatures and plants” (see page 36).

• We cannot see or taste air

• We can detect changes in air temperature on our skins.We can feel the air moving around us.

• We can hear air moving as wind.Without air there would be no life on Earth. People can survive forabout a month without food, and a few days without water but we cannot survive without air for more than a few minutes.All living things need air. All animals as well as plants ‘breathe’ and use oxygen and give off carbon dioxide to stay alive.

80%

70%

60%

50%

40%

30%

20%

10%

0% Nitrogen Oxygen Carbon Others

dioxide

NOTE TO TEACHERS

Make sure learners understand

that plants use carbon dioxide to

make their own food as part of

the process of photosynthesis.

This is when they give off oxygen

into the atmosphere. However,

plants also ‘breathe’ in oxygen

to release energy for their own

growth and development.

Ga

ses

inp

erc

en

tag

es

A GRAPH TO SHOW THE GASES THAT CONSTITUTE AIR

Gases that constitute air

I can’t see

any Oxygen or

Nitrogen …

4

5

Read about air and the living things and discuss the following questions in your groups.1. Why is oxygen important for all living things? 2. How is oxygen carried to every cell in our bodies? 3. What do plants use carbon dioxide for? 4. Where do plants get carbon dioxide from?

Learner task

Why do we breathe air?When we breathe in, air goes into our lungs.

The oxygen in the air goes into the blood

vessels surrounding our lungs. The oxygen is

carried by the blood to every cell in our

bodies. Here the oxygen is used to break

down the food in the cells, and release the

energy stored in food.

We need the energy to move, think,

breathe, work and play. After the energy has

been released, carbon dioxide gas is given off

and carried by the blood back to the lungs.

The carbon dioxide is released into the lungs

where it mixes with air and is breathed out.

All animals and plants use oxygen and give

off carbon dioxide in order to produce the

energy for them to grow and develop.

However, plants also use carbon dioxide

from the air to make food. Plants take carbon

dioxide from the air and water from the soil

and energy from the sunlight to make food.

This process is called photosynthesis.

Photosynthesis means ‘making with light’.

The food that plants make is called starch.

When we eat foods containing starch such as

mealie-pap or potatoes, this starch was made

by the mealie plant and the potato plant.

During photosynthesis plants give out oxygen

into the air.


A bar graph to represent 1. The graph must have:the air as a mixture of gases a a suitable heading

a axes correctly labelleda a suitable scalea the bars shadeda the points accurately plotted

2. The graph must be plotted with the correct amounts of gas present in the air.

3. Nitrogen is the gas that makes up most of our air.

The question about air and Correct answers to the questions:living things a) Oxygen breaks down the food in the cells of our bodies and

the energy that all living things need is released.b) The blood from our lungs carries oxygen to every cell in our

bodies.c) Carbon dioxide is given off into the air when plants and

animals breathe.d) Plants use carbon dioxide for making their own food.

A. The Earth’s atmosphereActivityAAsssseessssmmeenntt 33

6

B. The layers of the atmosphere• The atmosphere extends to about 80km above the Earth’s surface• The atmosphere is made up of layers• All the air that we need for breathing occurs in only the first 10km

of air above the surface • The atmosphere protects the Earth’s surface from dangerous sun

radiation and from dust and rocks in space

1. Supply the learners with a drawing showing the layers of the Earth’satmosphere and the questions about each layer. (See page 37 tophotocopy for learners.)

2. Allow the learners to discuss the questions in their groups. 3. Make sure that the following points come out in the discussion:

A The atmosphere extends to about 80km above the Earth’s surfaceA The atmosphere is made up of layers.A All the air that we need for breathing occurs in only the first 10km

of air above the surface.A The atmosphere protects the Earth’s surface from dangerous sun

radiation and from dust and rocks in space.

Teacher task

THE LAYERS OF THE ATMOSPHEREIONOSPHEREThis layer absorbs dangerous rays from the sun.Radio waves coming fr om Earth reach this layer and are bounced back to a different part of theEarth where they are picked up by peoples’ TVs andradios. This is how radio programmes are transmittedaround the world.

MESOSPHEREThis layer is very cold (–100°C). It protects the Earth from rocks (meteors) and dust that fly into the atmosphere from space.

STRATOSPHEREThis layer is like a shield. It protects the Earth and living things from the sun’s dangerous rays.

TROPOSPHEREThis layer has all the air that we need for breathing.All animals and plants live in this layer. This layer has watervapour and clouds and this is where we find different kinds ofweather. The gases making up the Earth’s atmosphere becomeless and less the further you go away from the Earth until thereis no atmosphere at all in space.

SEA LEVELHalf of the atmosphere is below here

Key concepts

7

1. Look at the drawing of the Earth’s atmosphere.2. In your groups discuss the questions about each layer.

(a) In what layer of the Earth’s atmosphere are plants and animals ableto survive? Give a reason for your answer.

(b) Mountain climbers use oxygen when they climb to the top ofMount Everest. Why do you think they must carry extra oxygen?

(c) What does the stratosphere do? (d) Can a person survive in the Mesosphere? Give a reason for your

answer.(e) What would happen if the Earth had no atmosphere?

Learner task


Questions about the layers Correct answers to the questions about the layers of the of the atmosphere atmosphere i.e.

(a) Plants and animals live in the Troposphere. This is becausethe air that they need to breathe is in the Troposphere. Also inthe Troposphere they are protected from dangerous sun’srays and rocks and dust from space.

(b) They must carry extra oxygen because as you go further awayfrom the Earth’s surface, the amount of air becomes less. Sothere will not be enough oxygen.

(c) It protects the Earth and living things from the dangerous raysof the sun

(d) People cannot survive in the Mesosphere because it is toocold there and people are not protected from space dust androcks. They are also not protected from the sun’s dangerousrays.

(e) There would be no life on Earth. This is because there wouldbe no oxygen for the animals and plants to get energy. Therewould be no carbon dioxide for the plants to make food.There would be no protection from the sun’s dangerous raysand no protection from space rocks and dust.

B. The layers of the atmosphereActivityAAsssseessssmmeenntt 33

where doyou live?

in the

troposphere,

of course!

8

C. Our air is precious but we pollute it• The same air is used over and over again in the atmosphere • Many activities carried out by people pollute the atmosphere• Pollution of the air is dangerous to living things

1. Lead a class discussion about how air is polluted. Use the picture thatshows what pollutes our air to help the discussion (See page 38.)

2. In order to make sure that the learners understand that the same airthat we pollute gets used over and over again, ask questions like:“Where does this polluted air end up?” (The direction of the arrows inthe picture shows that the same air is used over and over again).

3. Supply the learners with the reading “The air is precious”. (See page38.)

The air is precious

The Earth’s air is the only air that we have. It is the same air that our

ancestors breathed. It is the same air that the dinosaurs once

breathed.

We breathe the same air that our dogs and cats breathe. The air we

breathe is the same air that has passed through our motor car engines

and factory chimneys and the plants outside.

The same air is used over and over again because it is the only air

that we have. We can’t get any more air from anywhere else.

When we make the air dirty from engines and factories, we call this

air pollution.

Key concepts

Teacher task

WHAT POLLUTES OUR AIR?This picture shows all the differentthings that pollute the air. Thepolluted air is used again and again.

9

Air pollutionWe say that the air is polluted when it becomes dirty.Substances that make the air dirty are produced in many differentways:A When we burn fossil fuels (coal and oil) in power stations to

make electricityA When we make things that require burning and

heating in factoriesA When we drive motor cars which always give

off fumesA When we burn rubbish and motor car tyresA When we burn grass, bushveld and trees

Strong sunlight interacts with the exhaust fumes from motor vehicles andthis can produce poisonous gases. Sometimes we can see and smellthese gases. They have a brownish colour and we call this smog. Smog isdangerous to plants and animals.

ugh! why do we haveto breathe yoursmelly fumes?

1. Participate in a class discussion about things that pollute the air.2. Read about “Air is precious” and “Air pollution” and answer the

questions that follow:(a) What are some of the things that pollute the air?

The things that pollute air are: smoke from power stations, fumes from car exhausts, smoke from burning and smoke from factories.

(b) Write to explain why some people are concerned that air isbecoming polluted.

Air pollution

People are concerned about polluting the air.

The reason why people worry is that this is the only air we have on Earth.

Another reason is that we use the same air over and over again, but if we make it dirty then we will only have dirty air to use.Another reason is that dirty air is dangerous to living things.

(c) Write a praise poem about air. For example:

My precious airWithout you I have no life My parents my, my friends, my cat and everybody.One single breath and my whole body is alive!Trees big and small, Beautiful flowers with insects around depend on you!Without you we all have no life.Thank you for being around for us

Learner task

whew! this pollution is really bad

for me!

10

C. Our precious air that we polluteWhat we want to assess What we expect from learners

Writing a paragraph to explain The paragraph must:why people are concerned a have a headingabout air pollution a have sentences that explain why

people are concerned about air pollution

a have sentences that make sensea contain key words about pollution

e.g. burn, fumes, smog, factories etc.

ActivityAAsssseessssmmeenntt 33

11

Our Earth is a planet

1. Below is a picture of the Earth.

2. Find any other picture of Earth that shows its physical features.3. Show learners the pictures and ask the following questions to

stimulate their curiosity about our Earth.

Earth – Our Home PlanetA What continents can you see?A Can you see any rivers and islands?A What are the white marks? Do you think they are fog, ocean currents,

clouds or waves?A Can you see both polar ice caps?3. Give learners a reading about planet Earth and the sun. (See “The

Earth is a planet” and “The sun is a star” page 39.)

• The Earth moves in space and it is a planet• The Earth rotates on its axis and revolves around the sun in its

own orbit• It is the only planet that has life as far as we know• The Earth gets its heat and light from the sun• The sun is a star and not a planet

Activity 44

Key concepts

Teacher task

polar ice cap

continent of Africa

Asia

clouds

clouds

Great LakesAtlantic Ocean

Island of Madagascar

South America

12

1. Complete the following table to compare our Earth and the sun.

Questions EARTH SUN

1. Is it a planet or a star? planet star

2. What is it made of? rock very hot gases

3. Does it give out light and heat? no yes

4. Which is bigger, the Earth or the sun? small big

5. Can life survive on it? yes no

2. Write sentences to compare the differences between planet Earth andthe sun. (Use the table to help you), e.g.

1. The Earth is different from the sun because it is a planet whereas the sun is a star.

2. Earth is made up of rock whereas the sun is made up of very hot gases.

3. The sun gives off light and heat whereas the planet Earth gets its heat and light from the sun.

4. The sun is bigger than the Earth.5. Planet Earth has living things such as plants and animals

whereas living things can never survive on the sun.

Learner task

The sun just looks smallerbecause it is

very far away!

To: N. Khumalo

23 NY 52

Guguletu

Cape Town

Western Cape

South Africa

Africa

Earth, The

Solar System

Earth is a planet.The sun is

a star.

Yes, the sun is much,much bigger.

SUN

= STAR

That’s where I live!

It’s theONLY place

to live!

Earth is awonderful

place to liveon!

13

There are nine planets around the sun

1. Explain to the learners that there are nine planets altogether thatrevolve around the sun.

2. Give each group of learners a set of the “Nine Planets” (page 40–43).

1. Read about the different planets and answer the following questions:(a) Which planet has rings? (b) Name the planet that has a red spot.(c) What do scientists think of this red spot?(d) Which planet is the windiest?(e) Which planet has craters like the moon?

2. Write each planet’s name and its distance from the sun at the back ofeach planet picture.

3. Cut out the planets.4. Start with the sun and place the planets in their correct position,

starting with the closest planet to the sun.5. Display these on the wall of your classroom.

• There are nine planets that revolve around the sun• Each planet revolves around the sun in its own orbit• The sun and all the planets that move around it form the solar

system• Each planet moves at its own distance from the sun• Each planet can be recognised by its appearance

Activity 55

Key concepts

Teacher task

Learner task

14

Teacher Input:Explain to the learners that the sun with its family of planets that move aroundit is called the solar system.

Give learners the task card about the solar system and the planet fact sheet(pages 44–46).

Learner Task Card – The Solar SystemUse the planet fact sheet and answer the questions that follow:1. Label all the planets’ names on the drawing of the sun and its family of

planets (solar system).2. Complete the following

A The hottest planet is Venus.A The coldest planet is Pluto.A The biggest planet is Jupiter.A The smallest planet is Pluto.A The planet which is closest to the sun is Mercury.A The planet furthest from the sun is Pluto.A The planet which takes 365¢ days to travel around the sun is Earth.A The planet which takes longest to travel around the sun is Pluto.

3. Now use the information about the distances from the sun to calculate:(a) How far away are we from Mercury? 90 000 000 km(b) how far away are we from Pluto? 5 750 000 000 km(c) how far away is our planet from Mars? 80 000 000

There are nine planets around the sun

Pluto

Neptune

SaturnEarth

MercuryVenus

MarsJupiter

Uranus

SUN

Learner task


The solar system (row of a The planets should be placed in their correct order according planets) to their distances from the sun; i.e. Mercury, Venus, Earth,

Mars, Jupiter, Saturn, Uranus, Neptune and Plutoa Planets’ names should be labeled

The solar system a The planets should be labeled with their correct names on(diagram + questions) the diagram

a Correct interpretation of the planet fact sheet tables, i.e. correct answers to questions 2

a Correct answers for question 3:(a) 90 000 000 km(b) 5 750 000 000 km(c) 80 000 000 km


Learner task

15

The inside of the Earth

A. The inside of the Earth is made up of layers

1. Use the paper model of the Earth made by the learners to remind themabout the outside appearance of the Earth.

2. Now find out from the learners what they think the inside of the Earthlooks like.

3. Supply each learner with one ‘Astro’ sweet so that learners can beginto imagine what the inside of the Earth is like.

1. Suck an ‘astro’ sweet and find out the following asyou suck it:A How does each layer feel?A How many layers does it have?

2. Make a drawing to represent the layers of the‘Astro’ sweet.

1. Explain the following to the learners:A Scientists think that the Earth has

different layers like the ‘astro’ sweet.A Like the astro, these layers are

arranged on top of each other andaround a common centre (concentric)

2. Show learners a drawing that shows theinside of the Earth and inform them that asection has been cut out so that we cansee what the Earth looks like inside.

• Scientists think that the inside of the Earth is made up of four concentric layers (layers arranged around a common centre)

Activity 66

Key concept

Teacher task

Learner task

crust

outside sugar coatinginside chocolatecrunchy inside

Teacher task

howmany

layers?

16

B. A play dough model to show the inside of the Earth

• The layers differ in thickness and in composition• The inner core at the very centre of the Earth is the hottest and is

solid• The outer core which surrounds the inner core is thought to be

molten rock• The mantle which covers the outer core is thought to be plastic

(partially melted rock – not completely solid)• The crust which is the outer layer is very thin and solid

Give learners the following:1. A reading about ‘Inside the Earth’ (see page 48).2. A task card to complete (see page 50).3. Play dough to make a model of the Earth.

1. Read about the inside of the Earth.2. Complete the task card about the inside of the Earth.

Learner Task Card – Inside the Earth1. Read about the different layers inside the Earth and complete the table

below.

2. Use play dough to make the model of the Earth. Use the following colours:red play dough to represent the hot inner coreorange play dough to represent the outer coreyellow play dough to represent the mantle white play dough to represent the Earth’s crust

3. Cut the model in half with cotton so that you can see inside.4. Then cut it into quarters.5. Hold three quarters together.6. Draw this cut-away section of

your model and label thedifferent layers inside Earth.

Teacher task

Learner task

Name of Earth’s layer INNER CORE OUTER CORE MANTLE CRUST

Thickness in km. (approx.) 1300 km 2250 km 2900 km 8–40 km

Position where found at the centre of around the above the outer most the Earth inner core outer core layer

look at that!

17

C. How big is Earth?1. Refer to the drawing of the cut-away section of the Earth’s inside

structure (See page ) and explain the following:A The radius is the distance from the centre to the edge A The circumference is the distance around a spherical

object2. Also explain to the learners how to calculate the

circumference of a circular object: i.e. circumference= 2 ∏ r (where ∏ = 22/7 and r = radius)

3. Give learners a task card about how big our Earth is tocalculate and complete. (See page xx.)

Teacher task

NOTE TO TEACHERS

Learners must have somebackground knowledge of whatcountries and conditions arefound around the equator to beable to write an imaginary journeyaround the Earth (question 5).They can use their atlases to seewhat countries, physical features,seas, forests etc. they will comeacross and they can do aresearch about these places.

Learner task

1. Calculate the radius of the Earth (its thickness from the centre to the edge)Radius of Earth = thickness of inner core + thickness of outer

core + thickness of mantle + thickness of crustRadius of Earth = 1300km + 2250km + 2900km + 40kmRadius of Earth = 6 490km

2. Calculate the diameter of the EarthDiameter of Earth = radius x 2Diameter of Earth = 6490 x 2Diameter.of Earth = 12 980km

3. Calculate the circumference of the Earth.

Circumference = ∏ x diameter (∏= 227 )Circumference = 12 890 km x 227Circumference = 40 794,285 km

4. Calculate how many days it would take you to walkaround the circumference of the Earth. (You willwalk along the equator all the way round).Your walking speed is 4km/hourYou must walk all day and all night (24 hours).

A First calculate the distance you will walk in onewhole day (24 hours).In one hour you walk 4kmTherefore in 24 hours you walk 4km x 24 In one day (24 hours) you walk = 96km

A Then calculate how many days will it take to walk40 794,285kmIn one day you will walk 96km How many days to walk around the Earth? Days = 40 794,285 km

96Days = 424,94 daysTherefore it will take me 424,94 days to walk aroundthe Earth (a little longer than a year).

Imagine that you have to travel around the Earth along the equator.Write to tell about your journey.

N.B. You may use your atlas to see what places you will go past and usewhat you have learnt in Social Sciences about the conditions in theequatorial regions.

18

Aroundthe world in 425 days

I left home on the 22nd of October 1999 for theDemocratic Republic of Congo, where I was going to begin

my long journey around the world along the equator. As I startedthis journey I realized that most of my travelling would be through

water and tropical rain forests at the equator. I had my coolest clothingwith me because the temperature there is very high throughout the year.

In the Democratic Republic of Congo (DRC) I had to travel through tropical rainforests. I was stumbling and falling in the thickest plant growth I ever saw. I had to

push away the thought of meeting a fierce animal in that thick growth. I was grateful tothe small person I made friends with, who helped me to cut and clear my way through the

dense thicket with his panga. In the DRC there are small people called pygmies. I wonderedwhy these people were so small.

I traveled westwards through to Gabon to cross the Atlantic Ocean to South America. I wasthere in time to get a lift from one of the yachts (sailing boats) because there was a yacht race inGabon. Unfortunately the yacht race could not start because there was no wind to set the boats

sailing, so I had to use a motorboat to sail across the Atlantic Ocean.

I landed in Brazil, where I had to take a canoe and paddle across the Amazon River to get to thebottom of the Andes Mountains. When the river became narrower, I had to abandon the canoe and

walk to get to the bottom of the mountain. I had to put on strong shoes to climb around toEcuador. I could feel the cold air against my skin as I climbed higher and higher up the

mountain.

At the coast of Ecuador I got onto a boat, which passed the Galapagos Island across thePacific Ocean to Malaysia. I had to cross the Island of Borneo through the tropical rainforests. This time I used my experience to find my way through this dense forest. I hadto sail in a boat again to get to Sumatra and onto another boat to the beautiful Island

of Maldives. The long stretch of sunny beach of this island tempted me to stop fora short holiday. It was wonderful to lie back in the sun and think about all theadventures on my journey. By this time I was really feeling home sick and I

was ready to finish my long journey around the world.

I then took another boat trip back to my home continent,Africa - to the Republic of Somalia. I finally took this

last long trip by boat back home. Oh! It was agreat feeling to touch the South

African soil again.

Learner Task Card (Continued)

Learner task

19


The table and questions about the A Correct completion of the table, i. e concentric layers of the Earth – there should be correct information about each layer

– the crust is the thinnest layer– the inner core is the hottest layer

The play dough model of the Earth A the model should be sphericalA layers should be concentric, with the inner core as the

inner most layer, followed by the outer core, the mantle and the thin crust as the outer most layer of the Earth

Drawing of the cut-away section of The drawing should: the inside structure of the Earth A be clear and show all the layers more or less in their

correct thicknessesA be correctly labelledA show that it is a cut-away sectionA have a suitable heading

How big is the Earth? A correct calculations i.e. (taking 40 km as the thickness of the Earth’s crust)– radius = 6 490km– diameter = 12 980km– circumference = 40 794,28km– 424,94 days

Writing about the journey around The writing should explain:the Earth along the equator A preparations for the journey, for example what you will

need for the journey A what you expect to experience on the journey, for

example, kind of weather, other physical and political features of the Earth, what rivers, mountains, countries and people you would expect to meet on this journey

A

ActivityAAsssseessssmmeenntt 66 The inside of the Earth

20

Finding out more about our homeplanetA. We have volcanoes in our planet

1. Revise the previous activity and make sure the learners understandthat:A The Earth’s crust is very thin and it has weak spotsA It is very hot inside the EarthA The layer underneath the Earth’s crust is molten rock and it is very

hot2. Introduce the lesson about volcanoes by setting up the apparatus to

demonstrate a volcano as shown in the diagram.

3. Ask the questions below as the learners observe what is happening:(a) What is happening to the water?(b) What comes through the opening?(c) Why does this happen?

• There are weak spots on the Earth’s thin crust • A volcano erupts through the openings on these weak spots • A volcanic eruption happens when hot lava from molten rock

(magma) or volcanic ash just below the Earth’s crust shoots out through an opening called a vent at the crust’s weak spots

• This eruption occurs because of the heat and pressure from inside the Earth

Activity 77

Key concepts

Teacher task

Cork stopper with a hole

Water level

Small glass pill bottle

Wire gauze

Tripod stand

Spirit burner

Demonstration to show how a volcano works

NOTE TO

TEACHER …Use a small glass pill bottle. Fill it

up to the top with water and then

press the cork in well. Use a

tissue to mop up any water that

comes out of the hole. Then begin

to heat the water. As the water in

the pill bottle begins to boil,

pressure in the bottle rises and

water and steam begin to bubble

out of the hole like a volcano.

21

4. Discuss answers to these questions introducing terms like:A heating, boiling, pressure, eruption, erupting now and again, steam

5. Ask the learners if they know of any real situation where some of theseprocesses take place.

6. Show learners the picture of Mount St. Helens (page 52).7. Now read and discuss the volcanic eruption of Mount St. Helens while

the learners follow in their own copies (pages 52–56).8. Show the learners where Mount St. Helens is on the world map (or on

their paper models of the Earth).

Read and participate in a class discussion about the volcanic eruption ofMount St. Helens.

looks like theprincipal iseruptingagain!

Mt St. Helens

Learner task

22

Teachers’ copy

Inside a volcano

1. Explain how a volcanic eruption happens using the big diagram of avolcano (page 58), and introduce terms like vent at the Earth’s weakspots on the crust, molten rock (magma), hot lava, cone, volcanic ashetc.

2. Give learners a task card “Comparing a demonstration of a volcanoand a real volcano” (see page 59).

3. Learners can read about other volcanoes on page 57.

Teacher task

Heat from the centre of the Earth

Earth’scrust

Main vent

Side vent

Steam, ashand lava

Crater

Very hot molten(melted) rock

Cone

Hotlava

Learner task cardComparing a demonstration of a volcano and a realvolcano

1. Label the diagrams and complete the table below.

2. Write to tell what happens in a real volcanic eruption.

Volcanic eruptionToday we learnt about volcanic eruptions.

I learnt that there are weak spots known as vents on the Earth’s thin

crust through which volcanoes erupt.

I also learnt that heat and pressure cause hot lava known as magma

from molten rock to shoot out through these vents from just below the

Earth’s crust.

The other thing I learnt was people live near volcanoes because the

soil becomes rich with minerals and they can grow their crops.

Finally I learnt that volcanoes can erupt at any time, some are waiting

to erupt whereas others are dead.

23

Heat from thecentre of the Earth

Earth’scrust

Mainvent

Sidevent

Steam, ashand lavaCrater

Very hotmolten(melted)rock

Cone

Hotlava

Cork stopper witha holeWater level

Small glass bottle

Gauze

Tripod stand

Spirit burner

Learner task

Questions Demonstration volcano Real volcano

Where does the heat come from? flame centre of the Earth

What erupts out of the hole / vent? hot water and steam steam, ash, & hot lava

What causes this eruption? heat heat and pressure

24

Learner task card – Project1. Do some research about any volcano that once erupted in any part of

the world.2. In this research write sentences to say:

(a) Where and when the volcano erupted (b) What its visible effects were (c) Find out if there are any good things about that volcano.Write sentences about each aspect of the volcano on one page.

3. Make your own booklet about the volcano you researched by clipping(or sticking) your sentence pages together. Do not forget to write your name and an index.

Ideas for the booklet:Photograph of the volcano, world map with the place highlighted, detailsof the volcano written in full sentences with pictures where applicable.

A. We have volcanoes in our planet


Diagrams and writing: Comparing a demonstration of a volcano with a real volcanoa Diagrams should be correctly labeleda The table should be properly completed i.e. table should

show a clear understanding of what happens in a demonstration of a volcano and a real volcano

Writing about what happens a Writing should indicate that the learner understands a in a real volcano volcanic eruption, i.e. heat and pressure continuously push

up the hot lava from the molten rock (magma). A volcanic eruption happens when hot lava escapes through the vent on the weaker spots of the Earth’s crust.

Project: Readings and writing The learners should show that they understand theof sentences about volcanoes readings by:Producing a zigzag booklet a Indicating the country where the volcano erupted correctly on a volcano labeled on the paper model of the Earth

a Writing some good sentences with information about each group’s volcano

a Producing an attractive and informative zigzag booklet on their volcano

a Etc.

Learner task


NOTE TOTEACHERS

Learners can use the

readings about any

other volcanoes for their

project (see pages xx) or

they can use the library

for others.

25

B. We need minerals from the Earth’s crust in our lives

• Minerals used for making useful things such as watches andpieces of jewellery come from the crust of the Earth

• Minerals that are good for our bodies come from rocks and soil that are on the Earth’s crust

1. Introduce the term mineral. A mineral is a natural substance from whichrocks are made.

2. Explain that the Earth’s crust is made of rocks and soil which containminerals such as gold, diamond, clay, salt, silver etc.

3. Give learners copies of pages 62 and 63 to complete and the MineralFact Sheet on page 64.

Learner Task CardSo many things come from the Earth’s thin crust

1. Look at the picture of ‘King Arthur’ and think of all the minerals that areuseful to him that come from the Earth’s thin crust.

2. Now read the mineral fact sheet and answer the questions about eachmineral in the spaces on page 62–63.

3. Write five sentences to tell why the Earth’s crust and its minerals areimportant to us. I found out that minerals come from the Earth’s crust

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Teacher task

Learner task


Completing a table about a Should have correct information about where the mineral minerals comes from

Writing sentences about Sentences should say:minerals a what the mineral is

a where the mineral comes froma why we need that particular minerala

B. We need minerals from the Earth’s crustActivityAAsssseessssmmeenntt 77

26

PERIOD 1

Activity 1

• Choosing a shape whichbest resembles the shape ofthe Earth and explanationabout own choice

• Making of the Earth papermodel (±50 min)

PERIOD 2

Activity 2

• Putting of continents andcolouring in

• Discussion about Earthbeing mostly covered bywater (±50 min)

PERIOD 3

Activity 3

• Reading and answeringquestions about the gasesthat form the air (±50 min)

PERIOD 4

• Looking at the layers of theatmosphere and answeringquestions about them (±50 min)

PERIOD 5

• Reading about how preciousair is and how we pollute it

• Answering questions andwriting a praise poem aboutair (±50 min)

PERIOD 6

Activity 4

• Looking at the physicalfeatures of the Earth(±15 min)

• Reading about andcomparing planet Earth andthe sun (± 35 min)

PERIOD 7

Activity 5

• Reading about nine planetsand sequencing them (± 50 min)

PERIOD 8

• Interpreting a table aboutthe planets in the solarsystem (±50 min)

PERIOD 9

Activity 6a

• Revising Earth’s outsidefeatures and starting to thinkabout the inside structure(Astro sweet activity) (±50 min)

PERIOD 10

Activity 6b

• Looking at the Earth’s insidestructure diagram

• Reading about it andcompleting a table(±50 min)

PERIOD 11

Activity 6b (cont)

• Making the play doughmodel of the Earth

• Drawing the cut-awaysection of the model(±50 min)

PERIOD 12

Activity 6c

• Explanation of terminologyrelated to measurement ofcircles

• Learners doing calculationsand writing about theirimaginary journey aroundthe Earth along the equator (±50 min)

SUGGESTED WORKSCHEME

EARTH & BEYOND: GRADE 7

PERIOD 13

Activity 7

• Demonstration of a volcanowith learners observing andanswering questions

• Introduction of terminologyto do with a volcaniceruption(±50 min)

PERIOD 14

• Reading and discussingabout the Mount St. Helensvolcano (±50 min)

PERIOD 15

• Explanation of how a realvolcano happens

• Completion of a task cardcomparing a demonstrationof a volcano and a realvolcano(±50 min)

PERIOD 16

• Writing about what happensin a real volcanic situation(±50 min)

PERIOD 17

• Project:

A brief research about avolcano and showinglearners how to make theirown zigzag books(±50 min)

PERIOD 18

• Learners complete theirwriting and make theirzigzag books.(±50 min)

PERIOD 19

Activity 7b

• Introducing minerals

• Completing a task cardabout minerals (±50 min)

Total time to finish the activities in this learning programme = 19 PERIODS @ 50minutes per period = 950 min = close to 16 hours. This is about 4 weeks of work. (Recommended time per week for the Natural Sciences is 4 hours)

that’s what webreathe!

all these gasesare mixedtogether

30

Activity 3a – ReadingThe Earth’s atmosphere is a mixture of gasesThe air we breathe is a mixture of gases that surround the Earth in layers.Air keeps the Earth’s surface at just the right temperature to support life.These layers of air and other gases are also called the Earth’satmosphere.

The air we breathe also contains the following:A Water vapourA Fumes called hydrocarbons, which come from car exhausts, factories

and firesA Dust particlesA Other gases, in very small amounts; for example ozone, argon, neon,

helium and krypton

Air and living creatures and plantsA We cannot see or taste air. A We can detect changes in air temperature on

our skins. We can feel the air movingaround us.

A We can hear air moving as wind.

Without air there would be no life on Earth.

People can survive for about a month withoutfood, and a few days without water but we cannot survive without air for more than a few minutes.

All living things need air.

All animals as well as plants ‘breathe’ and useoxygen and give off carbon dioxide to stay alive.

20% oxygen

1% argon andother rare gases

less than 1%carbon dioxide

78% nitrogen

I can’t see

any Oxygen or

Nitrogen …

31

Graph paper

32

Activity 3a – Air and living creatures

Why do we breathe air?

When we breathe in, air goes into our lungs. The oxygen in the air goesinto the blood vessels surrounding our lungs.

The oxygen is carried by the blood to every cell in our bodies.

Here the oxygen is used to break down the food in the cells, and releasethe energy stored in food. We need the energy to move, think, breathe,work and play. After the energy has been released, carbon dioxide gas isgiven off and carried by the blood back to the lungs. The carbon dioxideis released into the lungs where it mixes with air and is breathed out.

All animals and plants use oxygen and give off carbon dioxide in order toproduce the energy for them to grow and develop.

However, plants also use carbon dioxide from the air to make food.

Plants take carbon dioxide from the air and water from the soil and energyfrom the sunlight to make food. This process is called photosynthesis.Photosynthesis means ‘making with light’.

The food that plants make is called starch. When we eat foods containingstarch such as mealie-pap or potatoes, this starch was made by themealie plant and the potato plant.

During photosynthesis plants give out oxygen into the air.

Read about air and the living things and discuss the following questions in your groups.1. Why is oxygen important for all living things? 2. How is oxygen carried to every cell in our bodies? 3. What do plants use carbon dioxide for? 4. Where do plants get carbon dioxide from?

IONOSPHEREThis layer absorbs dangerous raysfrom the sun. Radio waves comingfrom Earth reach this layer and arebounced back to a different part ofthe Earth where they are picked upby peoples’ TVs and radios. This ishow radio programmes aretransmitted around the world.

MESOSPHEREThis layer is very cold (–100°C). Itprotects the Earth from rocks (meteors)and dust that fly into the atmospherefrom space.

STRATOSPHEREThis layer is like a shield. It protects theEarth and living things from the sun’sdangerous rays.

TROPOSPHEREThis layer has all the air that we need forbreathing.All animals and plants live in this layer. Thislayer has water vapour and clouds and this iswhere we find different kinds of weather. Thegases making up the Earth’s atmosphere becomeless and less the further you go away from theEarth until there is no atmosphere at all in space.

Half of the atmosphere is below here

The gases making up the Earth’s atmospherebecome less the further you go away from the Earthuntil there is no atmosphere in space.

Activity 3b – Layers of the atmosphere

33

34

Activity 3c What pollutes the air?The air is precious

The Earth’s air is the only air that we have. It is the same air that ourancestors breathed. It is the same air that the dinosaurs once breathed.

We breathe the same air that our dogs and cats breathe. The air webreathe is the same air that has passed through our motor car enginesand factory chimneys and the plants outside.

The same air is used over and over again because it is the only air that wehave. We can’t get any more air from anywhere else.

When we make the air dirty from engines and factories, we call thispolluting the air.

Air pollution

We say that the air is polluted when it becomes dirty.

Substances that make the air dirty are produced in many different ways:A When we burn fossil fuels (coal and oil) in power stations to make

electricityA When we make things that require burning and heating in factoriesA When we drive motor cars which always give off fumesA When we burn rubbish and motor car tyresA When we burn grass, bushveld and trees.

Strong sunlight interacts with the exhaust fumes frommotor vehicles and this can produce poisonousgases. Sometimes we can see and smell these gases.They have a brownish colour and we call this smog.Smog is dangerous to plants and animals.

WHAT POLLUTES OUR AIR?

This picture shows all the different things that pollute the air. The polluted air is used again and again.

35

Activity 4 – Reading

The Earth is a planetThe Earth is a planet. It is shaped like a ball and it moves through spacearound the sun on its own pathway known as the orbit. It gets its heat andlight from the sun. It is the only planet that has life as far as we know. It ismade up of rock whereas other planets are made up of rock and gas.

The sun is a starThe sun is a star and not a planet. It is a huge ball of very hot gases. Itgives off light and heat. It is the closest star to planet Earth. We get heatand light from our local star, which is the sun. It is more than hundredtimes bigger than the Earth. The sun has nine planets including the Earththat move around it in space.

Learner Task – Activity 41. Complete the following table to compare our Earth and the sun.

Questions EARTH SUN

1. Is it a planet or a star?

2. What is it made of?

3. Does it give out light and heat?

4. Which is bigger, the Earth or the sun?

5. Can life survive on it?

2. Write sentences to compare the differences between planet Earth andthe sun. (Use the table to help you.)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The Earth The sun

The nine planets in our solar system

36

All pictures courtesy NASA

The four Galilean moons

Jupiter has 16 knownmoons, but four arelarger than the restand can be seeneasily withbinoculars. They areknown as the“Galilean moons”after their discovererGalileo.

JupiterDiameter 142 800 km

Mass 318 Earth masses

Distance from the sun 800 million km

Number of moons 16

Rotation period length of day in Earth hours 9.8

Time to go round the sun length of year in Earth years 11.9

Jupiter is the largest of the gas giants. The whiteclouds that we see are at a temperature of –153°Cand consist of ammonia ice crystals. Lower down,the clouds are coloured red and brown by organiccompounds and chemicals such as sulphur. Windsspeeds of over 400 km/h are common; the GreatRed Spot is thought to be a long-lived hurricaneand is larger than Earth. Jupiter probably has a rockor ice core surrounded by liquid hydrogen withhelium dissolved in it.

37

MercuryDiameter 4 878 km

Mass 0.06 Earth masses

Distance from Sun 60 million km

Number of moons none

Rotation period length of day in Earth days 58.7

Time to go round the sun length of year in Earth days 88

At the equator it is hot enough to melt lead. Atthe poles there are craters with ice frozen to–150°C. Mercury has no atmosphere.

UranusDiameter 51 118 km


Distance from the sun 3000 million km

Number of moons 15

Rotation period length of day in Earth hours 17.9

Time to go round the sunlength of year in Earth years 84

Uranus shows an almost featureless green‘surface’ of clouds floating in a cold (–197°C)atmosphere of hydrogen, helium and methane.Beneath the clouds, most of Uranus (85%) isice.

EarthOur Home Planet

Diameter 12 750 km

Distance from sun 150 million km

Rotation period length of day in Earth hours

23.93

Time to go round length of year in the sun Earth days365.24

38

Venus Diameter 12 104 km


Distance from Sun 104 million km

Number of moons none

Rotation period length of day in Earth days 243

Time to go round the sun length of year in Earth days 225

Venus is a hot and hostile planet. An atmosphere ofcarbon dioxide 90 times as dense as Earth’s keepsthe surface hot enough to melt lead. Clouds ofsulphuric acid hide its surface.

SaturnLike Jupiter, Saturn is a gas giantconsisting mainly of hydrogen andhelium. Its famous ring in fact consistsof thousands of narrow rings made upof lumps of ice and rock as small asdust grains and as large as a minibus.

Diameter 120 660 kmMass 95 Earth massesDistance from Sun 1 400 million kmNumber of moons 18Rotation period length of day in Earth hours 10.2Time to go round the sun length of year in Earth years 29.5

MarsDiameter 6 787 kmMass 0.1 Earth massesDistance from Sun 240 million kmNumber of moons Two. Phobos and DeimosRotation period length of day in Earth hours

24.62Time to go round length of year in Earth the sun days 687

The atmosphere of Mars is 100 times less densethan Earth’s and consists mainly of carbon dioxide,with traces of water vapour. In winter temperaturesdrop to –125 °C, giving Mars its well known white‘ice caps’. In summer equatorial temperatures canreach 20 °C. The planet’s reddish colour is causedby iron in the soil. Bacterial life forms may oncehave existed on Mars.

NeptuneDiameter 49 528 km

Mass 17 Earth masses

Distance from sun 4 500 million km

Number of moons 8

Rotation period length of day in Earthhours 19.1

Time to go round the sun length of year in Earthyears 164.8

Neptune is another ‘ice giant’ like Uranus and evencolder (–225°C). Its bluish atmosphere of hydrogenand helium shows occasional large dark spots, and isprobably the windiest place in the solar system withstorm winds reaching speeds of 1400 km/h.

39

PlutoDiameter 2 300 kmMass 0.0025 Earth masses Distance from sun 4 400–7 400 million kmNumber of moons 1Rotation period length of day in Earth days 6.4Time to go round the sun

length of year in Earth years 247.7

Pluto is smallest of the planets, and usually theremotest and coldest. At –233°C, frost of methaneand nitrogen coat the pinkish surface. Pluto’s grayishmoon, Charon, is only 19 400 km away, and more thanhalf Pluto’s diameter.

40

The Solar System

41

SUN

42

PLANET Distance from Size of planet Number Other featuresthe sun in km (diameter in km) of moons

Mercury 60 000 000 km 5 000 km 0 It looks like our moon

Venus 104 000 000 km 12 000 km 0 It is the brightest planet

Earth 150 000 000 km 13 000 km 1 It is the only planet known to have life on it

Mars 240 000 000 km 7 000 km 2 It is known as the red planet

Jupiter 800 000 000 km 143 000 km 16 It has a red spot and striped appearance

Saturn 1 400 000 000km 120 000 km 18 It has a set of rings around it

Uranus 3 000 000000km 52 000 km 15 It looks green. Most of it is ice.

Neptune 4 500 000 000km 50 000 km 8 It appears blue

Pluto 5 900 000 000km 2 000 km 1 Very little is known about this planet

The Planets fact sheet

43

Learner Task Card – Activity 5

The Solar SystemUse the Planets fact sheet and answer the questions that follow:

1. Label all the planets’ names on the drawing of the sun and its family ofplanets (solar system)

2. Complete the following

• The hottest planet is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• The coldest planet is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• The biggest planet is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• The smallest planet is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• The planet which is closest to the sun is . . . . . . . . . . . . . . . . . . . . .

• The planet furthest from the sun is . . . . . . . . . . . . . . . . . . . . . . . . . .

• The planet which takes 365¢ days to travel around the sun is

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• The planet which takes longest to travel around the sun is

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3. Now use the information about the distances from the sun to

calculate:

(a) How far away are we from Mercury . . . . . . . . . . . . . . . . . . . .km.

(b) How far away are we from Pluto . . . . . . . . . . . . . . . . . . . . . .km

(c) How far away is our planet from Mars . . . . . . . . . . . . . . . . . .km

The solar system

44

Activity 6 B. Inside the Earth

The Earth’s Inner CoreThe inner core is at the very centre of the Earth. This is a very dense layermade of metals such as iron and nickel. The temperature of the innercore reaches about 5 000°C. Iron and Nickel will usually melt at thistemperature, but the enormous pressure from the layers above pushes theparticles of iron and nickel so tightly together that they remain solid.

The iron in the inner core may explain why there is a magnetic field aroundthe Earth. Scientists think that the iron produces an effect similar to themagnetic field around a magnet.

The thickness (radius) from the centre of the inner core to its edge isabout 1 300 kilometers (km).

The inner core is about 5 150 km below the Earth’s surface.

The Earth’s Outer CoreThe outer core surrounds the inner core. The outer core is also made ofiron and nickel. This layer is also very hot. The temperature in the upperpart is about 2 200° C but near to the inner core, the temperature isalmost 5 000°C. This tremendous heat makes the iron and nickel in theouter core melt. We say it is molten. This means it is like a very hot liquid.

crust

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The outer core is about 2 250 km thick and it is about 2 900 km below theEarth surface.

The Earth’s MantleThe mantle is the layer of the Earth that lies above the outer core. Most ofthe Earth is made up of the mantle (about 80%). The Earth’s mantle ismade of some solid and some melted rock (magma) mixed together. Themantle is slightly soft and runny because it is hot. We say that it is ‘plastic’because it can bend to change its shape. This does not mean it is plasticbut it can behave like plastic.

The mantle is about 2 900 km thick.

The Earth’s CrustThe Earth’s crust is the thin outer layer of the Earth. All living things arefound on the Earth’s crust or just below and above it. The crust is solid. Itis not ‘plastic’ or molten like the other layers.

The crust is made of three types of solid rocks: igneous, sedimentary andmetamorphic rocks. These rocks contain mostly oxygen and silicon(sand). Other common minerals found in the Earth’s crust are aluminium,iron, calcium, sodium, potassium and magnesium. We also get preciousmetals such as gold in the crust.

The crust is thin, like the peel on an apple. It is much thinner than theother layers of the Earth. Its average thickness is only about 8 km.

The part of the crust beneath the oceans, called oceanic crust, is also thin(less than 10 km). Oceanic crust is made mostly of silicon, oxygen, ironand magnesium.

The crust beneath the continents, called continental crust, is about 32 kmthick. Beneath the mountains, continental crust is even thicker than 32 km.

RECIPE for PLAYDOUGH

INGREDIENTS:

1 cup flour

1 cup water

1 tablespoon oil

1 teaspoon cream of tartar

1 teaspoon food colouring

™ cup salt

METHOD:1. Put all the ingredients together in a pot2. Cook the mixture on moderate heat until it

goes thick like porridge (about 3 minutes)3. Wait for the mixture to cool off and roll it

into a ball(Put some flour on your hands first)

4. Store your dough in a plastic bag in thefridge

N.B. for making the play dough model of theEarth you will need four different colours.

1. Plain white dough (no food colouring) for thecrust

2. Yellow dough (add yellow food colouring) forthe mantle - so you need a lot

3. Orange dough (mix red and yellow foodcolouring) for the outer-core

4. Red dough (add red food colouring) for theinner-core.

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Learner Task Card – Activity 6

B. Inside the Earth1. Read about the different layers of the Earth and complete the table

below.

2. Use play dough to make a model of the Earth. N.B. Use the following coloursred play dough to represent the hot inner coreorange play dough to represent the outer coreyellow play dough to represent the mantle white play dough to represent the Earth’s crust

3. Cut the model in half with cotton so that you can see inside. 4. Then cut it into quarters.5. Hold three quarters together. 6. Draw this cut-away section of your model and label the different layers

inside Earth.

Name of Earth’s layer INNER CORE OUTER CORE MANTLE CRUST

Thickness in km.(approx.)

Position where found

Cut the model inhalf with a pieceof cotton

This is what you get …

Use red play dough to representthe hot inner core. Cover it withorange play dough to representthe outer core.

Wrap yellow play dougharound to represent themantel.

Put on the final layer of whiteplay dough to represent thecrust.

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Learner task card – Activity 6

C. How big is our Earth?1. Calculate the radius of the Earth. (Its thickness from the centre to the edge.) . . . . . . . . . . . . .

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2. Calculate the diameter of the Earth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. Calculate the circumference of the Earth: circumference = ∏ x diameter (∏ = 227

).

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4. Calculate how many days it would take you to walk around the circumference of the Earth (you will walk along the equator all the way round).

Your walking speed is 4km/hours. You must walk all day and all night (24 hours).

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Writing task Activity 6 – How big is our Earth?Imagine that you have to travel around the Earth along the equator write to tell about your journey.

N.B. You may use your atlas to see what places you will go past and use what you have learnt inSocial Sciences about the conditions in the equatorial regions.

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48

Mount St. Helens was like a time bomb,ticking away towards “self-destruction”.Seven weeks before the eruption, the

world heard that the mountain was a dangerbecause ash and steam began to pour out of thetop of it. Mount St Helens is usually covered withlayers of ice and snow. It is in southwesternWashington in America. This is a beautiful land ofdeep forests, rushing streams, rich farmlands andnearby cities.

The people waited anxiously as theyexperienced small eruptions and earthquakesfrom Mount St Helens. Days and weeks passedwithout disaster and people began to relax. Everynow and then the volcano shook the ground andthe steam and ash appeared. But many peoplethought that the mountain seemed to be calmingdown. Then they noticed that its north side beganto bulge and grow bigger.

The eruption starts“This is it …” With those excited words, DavidJohnston, a geologist for the United StatesGeological Survey, announced the end of calmand the start of disaster. David was thirty yearsold and blond and bearded. He was six milesfrom Mount St Helens at a scientific station on theside of another mountain. He was studying MountSt Helens and watching for any changes anderuptions.

Those words were his last. The eruption he

reported was powerful and came out of the sideof the mountain. Red-hot rocks and steaminggases travelling at 400km an hour, blasted out ofthe mountain. It swept him and his researchstation off the side of the mountain to his death.His body has yet to be found.

What happened during the eruption – Sunday, 18May 1980In the first seconds of the eruption the side ofMount St Helens collapsed. This caused waves ofice to tumble down into the hot ash. Quickly the18,4 billion kilograms of ice melted, and about 46billion litres of water created a mud and waterflood.

It caused a disaster, sending mud, ash, brokentrees and rocks down the South Toutle RiverValley, for 30 km.

Like a monster, the flood destroyed the river,roads, trees, trucks, a few cars and caravans. Asthe flood swept on, a million tree logs tumbled onthe crest of the wave.

WHAT PEOPLE SAW AND EXPERIENCED

Eye-witness 1“There’s no way, there’s just no way anyone couldbe alive up there.” The camp is covered by morethan a metre of ash. The only sign of the camp isthe top of a car. It’s full of ash. The windows areblown in. I tried to blow the ash away but it boiledup. The ash was still very hot. “That’s where the

WAITING FOR THE ERUPTIONMount St Helens, Seattle, USA

49

village was!” There was no sign of the homes, nosign of a tree, a road, or anything familiar.

We saw 30-metre tall cranes fallen and twisted,bulldozers overturned, trucks buried or wrecked.Here and there we saw a car or bakkie with itswindows shattered. Were there victims inside?Here a body lies by a station wagon’s open door,there is another in the back of a truck.

Mud had also buried miles of the South ToutleRiver Valley, and floods had passed through,tossing acres of huge logs into chaos andwrecking a train.

An avalanche (mass of snow) swept thousands

of trees and other debris into the lake, which,along with water from the melting ice raised itswater level by about 60 metres.

Eye-witness 2They were flying in a small aeroplane directly overthe mountain at 8:32 a.m. on May 18.

“We arrived at 7:50 in the morning and flewtwice directly over the crater (the opening in thetop of the mountain) and several times around themountain,” Dorothy said. “The thing thatimpressed us was that it didn’t look like an activevolcano – more like one going to sleep.”

Then they saw a frightening sight: “We were

50

making a final flight over the crater when Keithstarted to see ice sliding off the mountain.Suddenly, the whole north half of the mountainbegan to slide away, directly beneath us! I wentinto shock. Keith took pictures while steamstarted to come out from under the snow.”

Then he ran out of film. “That’s what saved our lives, because then

Keith glanced over his shoulder and saw thesideways blast starting and recognised thedanger of our situation. He told the pilot, BruceJudson, that we had to get out of there.

“Bruce accelerated the plane. Ash began toexplode out of the mountain forming a hugecloud but we feared the ash cloud was going tocatch up with us. We were travelling east and sowas the cloud. Then we could see lightning in thecloud. Keith was afraid the lightning would strikethe plane. The pilot turned south and dived togain speed.”

Though the frightening cloud was like anumbrella overhead, they finally escaped.

“It took me a month to learn to relax,” Dorothysaid. Her mind plays and replays the thought thatIf they had stayed a few seconds more, that littleaeroplane would have flipped and fallen like aburned grasshopper, and they would have died.

“I felt a growing fear for all of us living on aplanet, whose crust is so thin and fragile, on topof such terrible heat and pressure. Never again,would I feel safe about this world we live on.”

Eye-witness 3“There was no sound to it, not a sound – it was likea silent movie, and we were all in it. First the ashcloud shot out to the east, then to the west, thensome lighter cloud started shooting straight up.At the same time the ash started coming rightdown towards us. I could see boulders – theymust have been huge – being hurled out of themountain.

“In frantic haste that seemed in slow motion,we scurried into six trucks and dashed towardsafety over mountain roads. We were the luckyones. Only the day before, we had been workingon the northeast side of the mountain, now adead gray hell.”

Some 35km away, a group of four men cuttingtrees was caught by the blast. They tried to walkout, their scorched clothing sticking to theirburned skin. One man climbed a tree to escapethe fiery blanket of ash, and his body was found

there weeks later. After eight hours a helicopterrescued the other three, two of whom died in ahospital.

Eye-witness 4. “This black, black cloud, of a blackness like I hadnever seen, came over, and of course we thoughtit was going to be a tremendous rainstorm. Thenwe could see little drops on the lake, and welooked at our coats and saw we weren’t gettingwet. Then it all occurred to us that it had to be aneruption of Mount St. Helens.

So we dashed for camp, but by the time westarted packing we had to use torches. The onlyway we could see to drive was to look for theedge of the road – all the time hoping no one wasstopped in front of us.”

Eye-witness 5A death toll of hundreds – even thousands –seemed likely that Sunday, May 18, as themountain erupted inside out. The ash sweptdarkly over the beautiful Yakima Valley, acrossfields of wheat around Moses Lake and a towncalled Ritzville and settled on other cities. Cars,trucks, buses, trains and planes stopped. Peoplecoming out of church, prayed on their way home.Service stations, restaurants and shops closed. The ash caused the electricity to fail. Thousandsof people travelling on the roads tried to findshelter in hotels, schools and homes. You couldsee nothing ahead of you, even with the carheadlights.

In the town of Yakima, midnight seemed toarrive at 9:30 in the morning and street lampsburned all day. In memory it has become BlackSunday.

The ash was composed of fine volcanic glassparticles; the cloud was itself a mass of sharpglass. Insects died as their bodies dried out in theheat. Some small creatures quickly choked.Some birds lost their way and could not see andfell to the ground. Larger animals were almostsuffocated and behaved strangely. Cattle anddeer and elk (a large buck with horns) wanderedaround in a daze.

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Life and Mount St. Helenswere one and the same forHarry Truman, 84. For morethan half a century he hadlived beneath the snowcrowned peak, where hebuilt a guest lodge besideSpirit Lake. Harry refused toflee last March when thevolcano, only five milesaway, awakened: “If I gotout of here, I wouldn’t live aday, not a day.” “I talk to themountain, the mountaintalks to me. I am part of thatmountain, the mountain ispart of me.” On May 18 St.Helens buried the lodgeunder hundreds of feet ofash and debris and theraised waters of Spirit Lake,and Harry’s words becamereality.

He refused to leave

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VESUVIUSVolcanic eruption, Italy, AD 79 In the year 79 AD three Roman towns, Stabiae,Herculaneum and Pompeii were destroyed whena volcano in mount Vesuvius erupted. The townssituated around the bay of Naples, were buriedunder tons of volcanic ash.

Pompeii was a successful market town and aport that traded in the products of the farms in thearea. The farmland was fertile because of thepresence of mineral-rich ash from the previouseruptions of Mount Vesuvius, which had beeninactive for hundreds of years.

Many of the residents of Herculaneum wereburned alive by the hot ash and gas. These werefollowed by dense flows of light rock calledpumice and ash which entombed (buried) thepeople who lived there.

HEIMAEYVolcanic eruption, Iceland, 1973On 23 January 1973 the ground split open on theisland of Heimaey in Iceland. Lava began to shootout 150 metres into the air. The people who wereliving there quickly made their way to the harbourand were taken to a place of safety.

On the night of the eruption, a wall of flaminglava roared into the air on the outskirts of the town.Houses burst into flames as streams of glowinglava swallowed them. People were not able tosave their homes or the island from beingswallowed by the lava and the ash.

The eruption lasted for five months. When itfinally stopped, two km long lava flow hadswallowed

a large section of the island. Fortunately onlyone life was lost, but 1 200 homes had beendestroyed.

MONT PELE’EVolcanic eruption, Martinique, West Indies1902In 1902, St. Pierre was the largest town on the tinyFrench island of Martinique which was home toabout 30 000 inhabitants. The people who livedhere were used to the rumbling noise of MontPele’e, which was 1,379 metres high and waslocated less than 8 kilometres away.

Mount Pele’e has been giving out gas since1889, but in April 1902 the volcano beganerupting. By May, people began to fear danger asclouds of steam and ash poured from thevolcano, darkening the sky and covering thestreets like a blanket of snow. Many people left St.Pierre after water from a crater was spat out by aneruption. Mud swept away a nearby factory with23 of the people who worked there.

A large black eruption cloud poured downMont Pele’e and raced through St. Pierre at aterrifying speed. The cloud was hot enough tomelt a glass. It happened so suddenly that peoplehad no time to take cover, let alone escape thedeadly cloud.

Within seconds the cloud had killed all but twoof the people of St. Pierre, Ciparis, a prisoner in anunderground cell and Leon the shoemaker.

NEVADO DEL RUIZVolcanic eruption, Colombia, South America1985An eruption of the remote Nevado del Ruizvolcano on 13 November 1985 caused thesecond deadliest volcanic tragedy of the twentiethcentury. The heat of the ash and the gasesreleased during the eruption melted a largesection of the mountain’s ice cap.

The water from the melting ice poured downthe mountain, carrying tons of sticky mud. Thismud flowed down a river valley near the town ofArmero, sending a 40 metre high wave of mudtowards the town. Around 21 000 people werekilled by the mud, along with over 1000 others inthe neighbouring villages.

The ash from the past eruptions enriched thesoils in the central parts of Colombia, creatingexcellent farm land. Armero a town with 23 000residents, had been located about 50 kilometersfrom the volcano and had been built up aroundwarehouses that stored rice, cotton and coffee,which was grown in the area.

MOUNT NYIRAGONGOVolcanic eruption, Goma, Democratic Republicof Congo, January 2002Tens of thousands of people were driven from thislarge town ahead of streaming lava when MountNyiragonga erupted early this year. More than 300

There have been others …

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55

Learner task card – Activity 7A. Comparing a demonstration of a volcano and areal volcano1. Label the diagrams and complete the table below.

2. Write to tell what happens in a real volcanic eruption.

Questions Demonstration volcano Real volcano

Where does the heat come from?

What erupts out of the hole / vent?

What causes this eruption?

Volcanic eruptionToday we learnt about volcanic eruptions.

I learnt that - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

I also learnt that - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

The other thing I learnt was - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Finally I learnt that - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

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Learner Task Card – Activity 7b

B. So many things come from the Earth’s thin crust1. Look at the picture of ‘King Arthur’ and think of all the minerals that are useful to him that come

from the Earth’s thin crust.

2. Now read the mineral fact sheet and answer the questions about each mineral in the spaces onpage 62–63.

3. Write five sentences to tell why the Earth’s crust and its minerals are important to us. I found out that minerals come from the Earth’s crust

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NAME OF MINERAL FACTS ABOUT IT

Gold Comes from deep inside the Earth’s crust. We have to dig deep mines to find it.

Silver Comes from rocks in the Earth’s crust. We have to dig mines to find it. We have to purify it from the rocks.

Salt Comes from sea water. Sea water is salty from minerals that have been washed from the land. We have to dry (evaporate) the sea water to get salt.

Diamonds Come from the Earth’s mantle and they get pushed up to the Earth’s crust during volcanic activities.

Chalk (lime) Is soft rock from the crust which has formed from many layers of dead sea animals and their shells.

Coal Is a rock formed from the bodies of dead plants and animals, which were buried under many layers of rocks. We find coal by digging deep mines in certain places in the crust.

Clay This is a mineral, which we find in soil. We find pure clay in certain parts of the crust. We can make clay pots from it.

Tungsten This is a metal, which is mined from the crust. We use it to make the wires of light bulbs.

Silicon Most sand on the surface of the Earth is made of silicon. When we melt it at a very high temperature it becomes glass.

Copper This is a metal, which we mine from the crust. We use it for making electrical wires.

Iron This is a metal, which is found in red soils. We have to heat the soil in a hot oven to get the iron out. We use it to make steel to produce nails and screws.

Iron in our bodies We have iron in our blood. It makes our blood red and carries oxygen. We get iron from eating plants which take up iron from the soil, e.g. green vegetables.

Fluoride This is a mineral found in water. It gets into water from the soil and the rocks. It is put into toothpaste to make our teeth strong.

Calcium Comes from soil. We get calcium from animals that eat plants that grow in the soil e.g. in cow’s milk. Calcium makes our bones strong.

Activity 7 B. Mineral fact sheet

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What does ‘king of kwaito’ Arthur Mofekate need?

So many things come from the Earth’s thin crust1. Look at the picture of ‘King Arthur’ and think of all the minerals that are

useful to him that come from the Earth’s thin crust.2. Now read the mineral fact sheet on page 64 and answer the questions

about each mineral in the spaces below.

3. Write about six sentences about minerals fromthe Earth’s crust. Remember to write a heading.You may begin like this:

I found out that we need minerals from the Earth’scrust. I know that minerals are important to mebecause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• His ear ring is madeof gold. Where didthe gold come from?

• Where do diamondscome from?

• Where does this chalkcome from?

• Where did the fluoride in his toothpastecome from?

• Where did the tungstenwires in this light bulb comefrom?

• Where did the silicon tomake glass comefrom?

• Where did the copper in the wires of these electrical appliances andequipment come from?

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• He uses salt to make his foodtasty. Where did it come from?

• Where did the calcium that madehis teeth and bones strong comefrom?

• This cutlery is made ofsilver. Where did it comefrom?

• Where did the clayto make this cupcome from?

• Where did the iron inhis food come from?

• Where does the coal forthis fireplace come from?

• Where did the iron and steel in his car come from?

earth and beyond [grade 7 english]

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