Energy And Change [grade 4 English]

WESTERN CAPE PRIMARY SCIENCE PROGRAMME An example of a short learning programme in the Natural Sciences and Technology

ENERGY

AND

CHANGE GRADE 4 Activity 1:

We use energy for everything we do

Activity 2: We get energy from food Activity 3: Food energy stories

Activity 4: Where does the energy in our homes come from?

Activity 5: Using energy – then and now

Activity 6: Making simple electrical circuits Activity 7: Making your own torch

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

©PSP 2002

DEVELOPED BY WESTERN CAPE PSP TEAM AND TEACHERS This learning programme will work towards the following learning outcomes in the Natural Sciences

K LO1: Scientific Investigations The 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 K LO2: Constructing Science Knowledge The learner will know and be able to interpret and apply scientific, technological and environmental knowledge K LO3: Science, Society and the Environment The learner will be able to demonstrate an understanding of the interrelationships between science and technology, society and the environment.

Course presented by Rose Thomas, Shane Nzwane and Sandra Mahote Booklet designed by Welma Odendaal and illustrated by Janet Ranson and Nicci Cairns Western Cape Primary Science Programme Edith Stephens Wetland Park Lansdowne Road Philippi 7785 PO Box 529 Howard Place 7450 Tel: 021 691-9039 Fax: 021 691-6350 e-mail: [email protected] website: www.psp.org.za

Contents • • •

This booklet illustrates an example of a short learning programme for Grade 4. 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.

2 . . . . . . . . . . . . . . . . . .Activity 1

– We use energy for everything we do

4 . . . . . . . . . . . . . . . . . .Activity 2

– We get energy from food

6 . . . . . . . . . . . . . . . . . .Activity 3

– Food energy stories

8 . . . . . . . . . . . . . . . . . .Activity 4

– Where does the energy in our homes come from?

10 . . . . . . . . . . . . . . . . . .Activity 5

– Using energy then and now

14 . . . . . . . . . . . . . . . . . .Activity 6

– Making electrical circuits

17 . . . . . . . . . . . . . . . . . .Activity 7

– Making your own torch

20 . . . . . . . . . . . . . . .Suggested workscheme 21–24 . . . . . . . . . . . . . . .Assessment sheets 25 . . . . . . . . . . . . . . .Codes for assessment Task cards to photocopy 26 . . . . . . . . . . . . . . . . .Activity 2

– Food gives us energy

30 . . . . . . . . . . . . . . . . .Activity 4

– Energy in our homes

32 . . . . . . . . . . . . . . . . . .Activity 5

– Energy available to people

36 . . . . . . . . . . . . . . . . .Activity 6

– Making a bulb light up

40 . . . . . . . . . . . . . . . . .Activity 7

– My torch

Support materials 42 . . . . . . . . . . . . . . . . .How light bulbs work 42 . . . . . . . . . . . . . . . . .Background information about batteries 43 . . . . . . . . . . . . . . . . . .Batteries and cells Back page . . . . . . . . . . .Mindmap about energy and change

Activity 1

We use energy for everything we do

Key concept

Teacher task

• We use energy for everything we do e.g. we use energy to move, to make sounds and to cook our food

1.

we use energy for everything we do.

In order to find out what the learners already know about energy, make a mind map on the chalkboard.

to c l e a n

ama ndl a

w r it

ENERGY e

b i cy c l a e ri d

2

2

e

s eb e tsa da nc e chew

Make flash cards with action words on them and let the learners read and do.

Using energy through actions Learner task

co ok f r u it a n d ve g

Read and do: a jump a run on the spot a make a windmill with your arms a shout your name a rub hands together to make them hot

Teacher task

Explain to the learners that to do all these things they use energy. Complete these sentences – e.g. we use energy to jump.

Learner task

1

We use energy to

ride a bicycle.

2

We use energy to

swing our arms

3

We use energy to

write.

4

We use energy to

dance

5

We use energy to

play.

3

Activity 2 Key concept Teacher task

We get energy from food • Food gives us the energy we need to keep us alive

1.

2.

Learner task

4

1. 2. 3.

Photocopy the following for learners: a labels – page 26. a picture of active children – page 28–29. Hand out the picture and the labels to the learners.

Look carefully at the picture and match each label with the action. Tell your group about each action on the picture. You can start like this: The girl is using energy for jumping.

Teacher task

Learner task

INDIVIDUAL

1. 2.

Learner Task Card: Food gives us energy 1. 2.

Task card to photocopy – page 27.

Point to a person in the picture who looks tired. Discuss the following with the learners. (a) Why is this person so tired? (b) How can this person get more energy to continue with his tasks? (c) What can he do to have more energy?

3.

Find on the picture people who are eating or drinking. Look at the picture of active children and say what kind of food gives them (each person) the energy they need to keep them active. Complete this paragraph about food as a source of energy for our bodies.

Food gives us energy We get energy from food. The girl is buying The boy is going to eat

a hot dog.

some popcorn and a hot dog

The food will give them energy to play sport this afternoon. I like to eat

porridge every morning because it gives me energy

to complete my tasks at school.

5

Activity 3 Key concepts

Teacher task

Food Energy Stories • Energy in our food comes from the sun • Energy is transferred in a sequence known as an energy story or a food chain Show learners how energy is transferred in a certain order from one living thing to the other and introduce the concept of an energy story (food chain). Example: a The girl gets energy from eating bread that is made from wheat. a The wheat plant gets energy from the sun. 1.

Match the sentences with the pictures and put them in a correct order to make a complete food energy story. Remember to end all your stories with the sun.

a

Thembi can run very fast because she gets energy from eating bread.

Learner task

1

2

a

The bread is made from wheat. It stores energy from the wheat.

a

The wheat plant gets energy to grow from the sun.

a

The sun gives heat and light energy.

a

The milk, which gives me energy, comes from the cow.

1

6

3

2

3

a

The cow gets energy from grass.

a

The grass gets energy from the sun.

a

The sun gives heat and light energy.

4

4

Learner task

(continued)

2.

Draw other energy stories and write sentences to tell the energy story. Each story should end with the sun. Ideas: a The energy story of a cyclist. a The energy story of a soccer player. a The energy story of a bird flying. a The energy story of a cat catching a mouse.

A s se ss m en t Activity

3

Food energy stories What we want to access

What we expect from learners

Matching pictures with sentences

a each sentence must be matched with the correct picture a the sentences with their matching pictures must be in a correct order to tell an energy story a The sequence must be: animal R green plant R sun

Drawing of other energy stories and writing sentences about them

a drawing must be clear a sentence must match the correct drawing a the drawings with their matching sentences must be in a correct order to tell an energy story a the sequence must be: animal R green plant R sun

7

Activity 4 Key concept Teacher task

Learner task

INDIVIDUAL

Where does the energy in our homes come from? • Heat energy in our homes comes from sources such as paraffin, gas, wood and electricity

Discuss and explain to learners what kind of energy we use to cook food.

Learner Task Card: Energy in our home 1.

2.

1

2

electricity

wood

3.

8

Look at each of these pictures and write on the space provided at the bottom to tell where heat energy for cooking comes from. Where does the heat energy in each of the pictures come from?

Task card to photocopy – page 30 and 31.

3

4

gas

paraffin

Look at the picture of the family in the kitchen and complete the table on the next page.

3

What is using energy

Where does the energy come from?

What does the energy do?

the kettle

gas

boils the water

the iron

wood

makes the iron hot

the lamp

paraffin

makes the lamp light up

the radio

batteries

makes the radio play

the fire

wood

burns to make fire that warms up the boys hand

Complete the sentences below. a) The kettle gets energy from gas to boil the water

gets energy from wood to make it hot. The lamp gets energy from paraffin to light up the room. The radio gets energy from batteries to play the music. The fire gets energy from burning wood to warm the boy’s hands.

b) The iron c) d) e)

As s es s m en t Activity

4

Where does the energy in our homes come from? What we want to access

What we expect from learners

Sources of heat energy

The learners must be able to: a identify the correct source of heat in each picture

Table completion

Table must be completed with: a correct source of energy for each user of energy a correct information of what the energy does

Sentences

Sentences must say: a where energy comes from a what energy does

9

Activity 5 Key concepts

Teacher task

Learner task

GROUP

Using energy then and now • People have always depended on energy to do things • People still depend on energy to do things • People use energy sources that are readily available to them

Hand out picture with appliances used by people – page 32.

1.

Look at the picture and discuss the following. (a) Which appliances were used long ago? (b) Which appliances are used mostly these days?

Appliances – then and now

10

Teacher task

1. 2. 3.

Hand out pictures with two families – page 34 and 35. Lead a discussion as to how these two families use energy. Refer to the questions on the Learners Task Card table – page 33. Write the relevant vocabulary on the chalkboard so that the learners can complete the table. Refer to the answers on the table for vocabulary – page 12.

Picture 1

Picture 2

11

Learner task

GROUP

Learner Task Card:

Task card to photocopy for learners – page 33.

Energy available to people Look at the pictures of families and complete the table below.

12

Questions

Picture 1

Does this use electricity?

1. What do they use to cook their food?

burn wood to make a fire for cooking

no

2. What do they use to light their house?

fire

no

3. What do they use to keep their house warm?

burn wood to make a fire

no

4. What do they use to entertain themselves?

sing, clap hands, tell stories and dance

no

5. What do they use to keep their food from going bad?

dried food / keep some in cooler parts of the house

no

6. What do they use to travel from place to place?

walked long distances

no

7. What do they use to make and care for their clothes?

cut and prepare animal skins for clothing

no

Questions

Picture 2

1. What do they use to cook their food?

electric stove

yes

2. What do they use to light their house?

electric lamps

yes

3. What do they use to keep their house warm?

oil heater

yes

4. What do they use to entertain themselves?

watch TV / go to the cinema

yes

5. What do they use to keep their food from going bad?

refrigerator and deep freezer

yes

6. What do they use to travel from place to place?

motor cars trains and planes

yes

7. What do they use to make and care for their clothes?

electric sewing machines and electric irons

yes

Does this use electricity?

Teacher task

1.

Discuss the ideas about the two families with the learners and point out the following: a many years ago, the only energy that people used to do work was the energy in their own bodies. a as the years went by people discovered fire. They found out that when they burned wood, the fire’s heat and light could be useful. a people also began to use animals for transport and to help them do jobs that needed lots of energy. a today many people use machines and electrical appliances that need lots of energy in the form of electricity. a people still also use energy sources that were used by people long ago because those are the energy sources available to them.

Write a conclusion about how people use energy. You may begin like this :

Learner task

People use the energy they can get easily

INDIVIDUAL Today I learnt that long ago people used fire for light in their houses. Today people use paraffin and electric lamps to light up their houses.

people walked long distances to get to where they wanted to be. But, today we use cars, buses and aeroplanes that use petrol and electricity. Another thing I learnt was

long ago people used to gather around fires singing songs, telling stories and clapping their hands to entertain themselves. But today people go to movies and watch television for entertainment. I also learnt that

today people use electricity for energy. But, people also still use energy sources and resources that were used long ago because it is what is available to them. Finally I learnt that

A ss e ss me n t Activity

5

Using energy then and now What we want to access

What we expect from learners

Table completion

Learners must write a appropriate answers about each picture whether electricity is used or not

Paragraph about what energy sources and energy resources people use

Sentences must a make sense a state the different energy sources and resources available to people

13

Activity 6 Key concepts

Teacher task

Making electrical circuits • Electricity travels along a path • The path along which electricity travels is a circuit • Electricity can only travel if the electricity pathway is not broken

1. 2.

Introduce the apparatus: cell, wire, bulb. Write their names on the chalkboard. Give each group of learners a cell, two wires and a bulb.

Learner Task Card A: Learner task

GROUP

Task card to photocopy, page 36–37.

Making a bulb light up 1. 2. 3.

Use the apparatus to make the bulb light up. Draw and label a diagram to show how you made the bulb light up. Write a paragraph to explain how you made the bulb light up. Remember to write a heading

wire

cell

light bulb

flow of electricity

for your paragraph.

How I made the bulb light up Today in class I made a bulb light up. This is how I did it.

I connected the one end of the first wire to one pole of the cell.

First Then

I connected the other end of the wire to the metal part of the bulb.

Thereafter

I connected one end of the second wire to the metal

pin at the bottom of the bulb. Finally

I connected the last end of the second wire to the

other pole of the cell and the bulb lit up. Teacher input 1. Explain to learners how the light bulb works. See teacher support material – page 39.

14

2.

Introduce key words and concepts: electrical circuit, electricity flows when the pathway is not broken.

Give each group of learners: 1 light bulb, wires, batteries and the task card called: Other simple electrical circuits to fill in. See correct answers below.

Teacher task

Learner Task Card B: Other simple electrical circuits Use your apparatus to see which electrical circuits work and which electrical circuits do not work.

Learner task

GROUP

Task card to photocopy – page 38. 1.

(a)

Do you think the bulb will light up? Yes

1

+

–

(b) Connect the wires, bulb and cell as shown on the picture. up? Yes 2.

(a)

Yes

Yes 3.

(a)

ü

No

ü

(b)

+

(a)

No

No

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

4.

Did it light

Do you think the bulb will light up? Yes

3

–

No

(b) Connect the wires, bulb and cell as shown on the picture. up?

+

Did it light

Do you think the bulb will light up?

2

–

No

No

ü

Do you think the bulb will light up? Yes

No

4 (b)

–

+

Connect the wires, bulb and cell as shown on the picture. Did it light up?

ü

No

Yes

No

Yes 5.

(a)

Do you think the bulb will light up?

5 (b)

–

+ –

+

Connect the wires, bulb and cell as shown on the picture. Did it light up?

ü

Yes

No

15

Learner task

(continued) 6. (a)

6

Yes

+

–

Do you think the bulb will light up?

–

+

(b)

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

7. (a)

7

+

(b)

(a)

8

+

–

+

(b)

ü

Activity

16

6

ü

No

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

As s e s s m en t

No

Do you think the bulb will light up? Yes

–

No

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

8

ü

No

Do you think the bulb will light up? Yes

–

+

–

No

No

Making electrical circuits

What we want to access

What we expect from learners

Making a bulb light up

Learners must: succeed in making the bulb light up

Drawing to show a circuit

The drawing must: a be clear a have correct labels a show a closed circuit

Paragraph to explain how a bulb was made to light up

The writing must: a have an appropriate heading a be logical a state how the bulb was made to light a have a correct use of concepts and key words. E.g: electricity goes through the wire, connect, bulb, cell etc.

Completing a table of electrical circuits

The table must show which circuits worked and which did not. E.g: circuits 2, 4, 5 and 8 worked, but circuits 1, 3, 6, and 7 did not work.

Activity 7 Key concepts

Teacher task

Making your own torch • Electricity can only flow in a torch if the path of the electricity is not broken • Electricity in a torch flows through the wire (filament) in the bulb and is changed into light 1. 2. 3. 4.

Show the diagram of the torch on the chalkboard. Disassemble a torch and refer to the diagram as you show the learners the different parts. Make sure learners know the essential parts – e.g. switch, bulb, and cell. Refer to the teacher support material. Give each group of learners a bulb, wires, and a battery to make their own torch. Learners can find any other materials to make a torch as well.

Project Task Card battery holder

switch

light bulb holder light bulb

reflector end piece

glass to protect light bulb base spring connection for battery batteries

17

Learner task

INDIVIDUAL

Task card to photocopy, page 40.

My torch 1.

Use the bulb, wires and battery together with any other suitable materials you can find to make your own torch.

2.

Present your torch to the group.

3.

Can it light up?

4.

Draw and label your torch.

5.

Write to tell someone how you made a torch.

How I made a torch What I used:

a bulb, a toilet roll cardboard, tin foil, transparent plastic, batteries, wires, sticky tape, prestik, and a paper cup.

What I did:

To begin with I cut the top of the paper cup off and I covered the remaining part with tin foil to make a reflector which I then sealed with transparent plastic.

Then

I cut the bottom of the paper cup and inserted the light bulb. Thereafter

I put two batteries with the opposite poles attached to each other and connected the wire to one end.

Continued on page 19

18

Next

I pushed the batteries with the wire into the battery holder made of toilet roll cardboard. I attached the loose end of the wire to the side of the light bulb and brought the metal end of the bulb in contact with the batteries.

Finally

I sticky-taped everything into position so that my torch would light up.

A s se ss m en t Activity

7

Making you own torch What we want to access

What we expect from learners

Diagram of a torch

The diagram should have correct labels.

Model of a torch

The model should be a working model – the torch should light up.

Drawing of own torch

The drawing should be clear. The labels should be correct and should point to the correct parts of the torch

Writing a procedure about making a torch

The writing must contain the following: a apparatus needed to make a torch a necessary steps followed to make the torch a the steps should be clear a the steps should be logical a key words should be correctly used

19

ENERGY AND CHANGE Suggested work scheme

Grade 4 learning programme PERIOD 1 Activity 1

PERIOD 2 Activity 2

PERIOD 3 Activity 3

PERIOD 4 Activity 4

• Prior knowledge about energy

• Matching actions with labels and talking about them. (15 min)

• Introducing food chains

• Discussion about heat energy used for cooking food

• Learners using energy through actions • Sentence completion. (50 min)

• Discussion about what gives us energy • Writing about food as a source of energy for us. (35 min)

• Matching sentences with pictures to make energy stories. (30 min) • Drawing and writing other energy stories. (20 min)

• Writing about sources of heat and light energy in our homes. (50 min)

PERIOD 5 Activity 5

PERIOD 6 Activity 5 (cont.)

PERIOD 7 Activity 6

PERIOD 8 Activity 6 (cont.)

• Discussion about families using energy

• Discussion about the results and teacher input. (30 min)

• Introducing components of a circuit. (5 min)

• Completion of task card about making a bulb light up. (50 min)

• Completion of table about energy available to people. (50 min)

• Writing about energy sources and energy resources available to people. (20 min)

• Completion of activity from task card about making a bulb light up. (45 min)

PERIOD 9 Activity 6 (cont.)

PERIOD 10 Activity 6 (cont.)

PERIOD 11 Activity 7

PERIOD 12 Activity 7 (cont.)

• Teacher input about how light bulbs work

• Completion about task card about simple circuits. (50 min)

• Taking the torch apart and naming the different parts of it. (10 min)

• Learners start the project about making a working model of a torch. (50 min)

• Introducing key words to do with circuits. (50 min)

• Learners labelling their torch diagrams. (40 min)

PERIOD 13 Activity 7 (cont.)

PERIOD 14 Activity 7 (cont.)

• The project continues (drawing and writing about own torch). (50 min)

• The project is completed. • Presentations and handing over of project

Total time to finish the activities in this Learning Programme = 14 periods @ 50 minutes per period = 11.6 hrs. This is 3 weeks’ work. Recommended time for Natural Sciences and Technology = 4 hours per week.

20

Task cards Photocopy for learners

Activity 2 Food gives us energy Labels

26

shouting

shouting

shouting

jumping

jumping

jumping

throwing

throwing

throwing

running

running

running

talking

talking

talking

laughing

laughing

laughing

making a noise

making a noise

making a noise

singing

singing

singing

shooting

shooting

shooting

Learner task

Activity 2

INDIVIDUAL

Learner Task Card Food gives us energy 1. 2. 3.

Find on the picture people who are eating or drinking. Look at the picture of active children and say what kind of food gives them (each person) the energy they need to keep them active. Complete this paragraph about food as a source of energy for our bodies.

Food gives us energy We get energy from food. The girl is buying————————————— ————————————————————————————————— The boy is going to eat —————————————————————— ————————————————————————————————— The food will give them energy to play sport this afternoon. I like to eat

------------------- every morning because it gives me

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

to complete my tasks at school.

27

Activity 2: ACTIVE CHILDREN

28

29

Learner task

INDIVIDUAL

Activity 4 Learner Task Card Energy in our homes 1.

1

Look at each of these pictures below and write on the space provided where the heat energy for cooking comes from.

2

3

4

Where does the heat energy come from? 1. ——————————————————————— 2. ——————————————————————— 3. ——————————————————————— 4. ——————————————————————— 2. 3. What is using energy the kettle

the iron

the lamp

the radio

the fire

30

Look at the picture of the family in the kitchen and complete the table below. Complete the sentences below: Where does the energy come from?

What does the energy do?

a. The kettle

gets energy from gas to boil the water.

b. The iron

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

c. The lamp - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - d. The radio e. The fire

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

31

Activity 5 Energy available to people

Learner Task Card Apliances - then and now

32

Activity 5 Learner Task Card: Energy available to people Look at the pictures of families and complete the table below. Questions

Picture 1

Does this use electricity?

Picture 2

Does this use electricity?

1. What do they use to cook their food? 2. What do they use to light their house? 3. What do they use to keep their house warm? 4. What do they use to entertain themselves? 5. What do they use to keep their food from going bad? 6. What do they use to travel from place to place? 7. What do they use to make and care for their clothes? Questions

1. What do they use to cook their food? 2. What do they use to light their house? 3. What do they use to keep their house warm? 4. What do they use to entertain themselves? 5. What do they use to keep their food from going bad? 6. What do they use to travel from place to place? 7. What do they use to make and care for their clothes?

33

Activity 5 Energy available to people Picture 1

34

Activity 5 Energy available to people Picture 2

35

Learner task

GROUP

Activity 6 Learner Task Card A: Making a bulb light up 1. 2.

Use the apparatus to make the bulb light up. Draw and label a diagram to show how you made the bulb light up.

Diagram

36

Learner Task Card A (continued) 3.

Write a paragraph to explain how you made the bulb light up. Remember to write a heading for your paragraph.

How I made the bulb light up Today in class I made a bulb light up. This is how I made it light up. To begin with I - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Then - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Thereafter - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Finally - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

37

Activity 6

Other simple electrical circuits

Learner Task Card B

Use your apparatus to see which electrical circuits work and which electrical circuits do not work. 1.

1

(a)

+

–

Do you think the bulb will light up? Yes

No

(b) Connect the wires, bulb and cell as shown on the picture. it light up? Yes

2

2.

(a)

3.

3

(a)

+

–

4.

(a)

+

–

5.

(a)

+

(b)

6. (a)

–

+

(b)

–

+

+

7. (a)

8

–

+

–

+

(a)

No

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

38

No

Do you think the bulb will light up? Yes

(b)

No

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

8

No

Do you think the bulb will light up? Yes

(b)

No

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

7

No

Do you think the bulb will light up? Yes

+

–

No

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

6

No

Do you think the bulb will light up? Yes

+ –

No

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

5

No

Do you think the bulb will light up? Yes

(b)

No

Connect the wires, bulb and cell as shown on the picture. Did it light up? Yes

4

No

Do you think the bulb will light up? Yes

(b)

–

No

(b) Connect the wires, bulb and cell as shown on the picture. it light up? Yes

–

No

Do you think the bulb will light up? Yes

+

–

Did

No

Did

Activity 7 Diagram of the parts of a torch 1.

Label the different parts

39

Learner task

INDIVIDUAL

Activity 7 Project chart: My torch 1. 2. 3. 4.

Use the bulb, wires and battery together with any other suitable materials you can find to make your own torch. Present your torch to the group. Can it light up? Draw and label your own torch.

Diagram

40

Activity 7 Project chart (continued) 5.

Write to tell someone how you made a torch.

How I made a torch Today in class I made a bulb light up. This is how I made it. What I used: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - What I did: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - To begin with - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------------------------------------------------------------------------------------------------------------------------------------------------Then - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Thereafter - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------------------------------------------------------------------------------------------------------------------------------------------------Next - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Then - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------------------------------------------------------------------------------------------------------------------------------------------------Finally - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -------------------------------------------------------------------------------------------------------------------------------------------------

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Teacher support How a light bulb works

A light bulb will light up when there is a pathway for electricity to flow through it. The electricity must flow from the one end (pole) of the battery through the electric wires, then through the filament (thin wire) inside the light bulb and then back to the other end (pole) of the battery. When you connect a light bulb you must make sure that there is one connection to the metal pin at the bottom of the bulb and another to the side metal casing around the base of the bulb. Electricity will always choose the shortest and easiest pathway along conductors. If the easiest route does not go through the filament the bulb will not light up.

This is what a light bulb looks like inside.

Background information about batteries (cells)

glass bulb

tungsten filament

metal casing

plastic pin metal pin

A torch battery is also sometimes called an electric cell. (Scientists use the term ‘battery’ for a number of cells.) The most common battery that we use is a dry cell battery, which has chemicals sealed inside a casing. The chemicals inside react together. This chemical reaction produces electricity, which can be used when the battery is connected into a circuit. When its chemicals have finished reacting, it stops working and cannot be recharged. We use very small dry cell batteries to power digital watches and pocket calculators. These have other chemicals inside them. Other batteries can be recharged with electricity and used again such as a cell (battery) for lap top computers. The car battery is made up of several lead-acid cells and these can be recharged.

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Batteries and cells Mercury battery

nickel-plated case

This type of battery is used for powering digital watches and pocket calculators. It is a mercury battery. An electrolyte is a liquid or moist substance which conducts electricity e.g. lemon juice, salt water, ammonium chloride paste.

electrolyte

zinx powder mercuric oxide and graphite

Dry cell battery The common dry cell battery produces a voltage of 1.5 volts. The zinc forms the battery casing. The electrolyte is ammonium chloride in the form of a moist paste. carbon rod (positive) zinc case (negative)

ammonium chloride paste

Lead acid battery The lead acid battery is used in cars. It is so called because it has electrodes that are made of lead, and the electrolyte is sulphuric acid. The battery consists of six sets of cells, which produce two volts each, for a total of 12 volts.

terminal top-up cover terminal

positive plate

cell

lead plates

casing

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