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TTTTopic: opic: opic: opic: How do you light bulb?How do you light bulb?How do you light bulb?How do you light bulb?

IntroductionIntroductionIntroductionIntroduction

Electricity is used as energy in our lives variously. To light the bulb is one way to use electricity.

This topic, we are

going to learn how to

light a bulb with a

dry cell.

SSSSubububub----ttttopic1opic1opic1opic1: L: L: L: Light with a bulight with a bulight with a bulight with a bulb and a dryb and a dryb and a dryb and a dry cell.cell.cell.cell.

1. Try a variety of connection with the bulb and dry cell. And identify in which connection a bulb lights.

Then, sketch them and write results

Example

Dry cell

+ (P+ (P+ (P+ (Positive)ositive)ositive)ositive) terminalterminalterminalterminal

---- (Negative)(Negative)(Negative)(Negative) terminalterminalterminalterminal

MATERIALSMATERIALSMATERIALSMATERIALS

Bulb

Cord

Socket

QQQQuestion uestion uestion uestion 1111

How do you light a bulb?

ExperimentExperimentExperimentExperiment 1 1 1 1 Identify in which connection a bulb lights.Identify in which connection a bulb lights.Identify in which connection a bulb lights.Identify in which connection a bulb lights.

Example

2

2. Organise results

3. Discussion :Make a conclusion from result

About :About :About :About : How do you How do you How do you How do you connectconnectconnectconnect, if you want a bulb to light?, if you want a bulb to light?, if you want a bulb to light?, if you want a bulb to light?

Exercise: Answer light or not for each of the following circuit.

a) b) c)

+ -

Trace from + to – to identify + and – terminals are connected with cord and bulb.

Example of circuitExample of circuitExample of circuitExample of circuit

A circuit shown below is a twisted ring. Even in this circuit a bulb can light.

As long as + and – terminals are connected with cord and bulb,

bulb lights. Because, electric current pass through a bulb.

Conclusion 1 Conclusion 1 Conclusion 1 Conclusion 1

If you want a bulb to light, +If you want a bulb to light, +If you want a bulb to light, +If you want a bulb to light, + (positive) and (positive) and (positive) and (positive) and –––– (negative) must be (negative) must be (negative) must be (negative) must be connectedconnectedconnectedconnected with cordswith cordswith cordswith cords.

When + (positive) and – (negative) are connected with

cords, cords become a path like as a ring which electricity

can pass.

This path is called “ElectricElectricElectricElectric circuitcircuitcircuitcircuit”.

If there is a bulb in the electric circuit, Electricity pass

through the bulb and the bulb lights. Electricity flow from

positive to negative. This flow is called ““““EEEElectric currentlectric currentlectric currentlectric current””””....

EEEElectric circuit and Electric currentlectric circuit and Electric currentlectric circuit and Electric currentlectric circuit and Electric current

3

1. Cut a cord nearby negative terminal.

2. Cut a cord nearby positive terminal

QuestionQuestionQuestionQuestion 2222

.If circuit is cut down, what will be happen?

ResultResultResultResult: L: L: L: Liiiight dieght dieght dieght die

CCCConconconconclusionlusionlusionlusion 2222

Wherever in the circuit you cut, light would die.

Dry cell

+ + + +

----

Bulb

Cord

Socket

MATERIALSMATERIALSMATERIALSMATERIALS

ResultResultResultResult: Light die : Light die : Light die : Light die

Experiment2Experiment2Experiment2Experiment2 Cut a circuitCut a circuitCut a circuitCut a circuit

4

Electric current is like as flow of cars going

around a circular road.

Right diagram show electric current flow

circuit smoothly.

When the road breaks down, all the cars

will stop at the same time.

Same as this, when the cord (wire) is

disconnected, electricity don’t flow.

That’s why a bulb doesn’t light

DDDDisconnectedisconnectedisconnectedisconnected circuitcircuitcircuitcircuit

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How to prepare cords and remove vinyl of cord

1 .Try a bulb to light with one and two cords

AAAAddddbicebicebicebice:::: DonDonDonDon’’’’t t t t connectconnectconnectconnect like shown as belowlike shown as belowlike shown as belowlike shown as below (short circuit)(short circuit)(short circuit)(short circuit)

DonDonDonDon’’’’t t t t connectconnectconnectconnect ONLY CORD with ONLY CORD with ONLY CORD with ONLY CORD with dry celldry celldry celldry cell. . . . AndAndAndAnd dondondondon’’’’t attach wire to wire. t attach wire to wire. t attach wire to wire. t attach wire to wire. CCCCircuit will heats up.ircuit will heats up.ircuit will heats up.ircuit will heats up.

ExperimentExperimentExperimentExperiment3333 Light Light Light Light a a a a bulb bulb bulb bulb without socket.without socket.without socket.without socket.

QuestionQuestionQuestionQuestion 3333

Which part of bulb doWhich part of bulb doWhich part of bulb doWhich part of bulb do you you you you connectconnectconnectconnect with cord or dry cell, If you want it to lightwith cord or dry cell, If you want it to lightwith cord or dry cell, If you want it to lightwith cord or dry cell, If you want it to light????

Example You can use sticky tape

Bulb Pair of cords Sticky tape Dry cell

+ + + +

----

15~20 cm15~20 cm15~20 cm15~20 cm

MATERIALSMATERIALSMATERIALSMATERIALS

2. Remove vinyl

3. Twist wire 4. Do the same things at both side

1. Cut only vinyl

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2. Organise result

3.Discussion : make a conclusion

AboutAboutAboutAbout:::: Which part of bulb did you Which part of bulb did you Which part of bulb did you Which part of bulb did you connectconnectconnectconnect with cord or with cord or with cord or with cord or dry celldry celldry celldry cell, when bulb lighted ?, when bulb lighted ?, when bulb lighted ?, when bulb lighted ?

bottom

side

bottom

side

Side

Bottom

CCCConclusioonclusioonclusioonclusionnnn 3333

When each terminal (positive and negative) is connected to side

and bottom respectively, a bulb is light

Question from conclusionQuestion from conclusionQuestion from conclusionQuestion from conclusion 3333

How is inside of bulb?

How is the path from bottom to side?

7

ExerciseExerciseExerciseExercise

Answer light or not for each of the following circuit. If you can’t predict, you can make circuits and identify.

ChallengingChallengingChallengingChallenging exerciseexerciseexerciseexercise

Bulbs shown below don’t light. Explain why each bulb doesn’t light.

a) b) c) d)

e) f) g) h)

a) b)

Socket

Filament

Inside of bulbInside of bulbInside of bulbInside of bulb

The inside of bulb is shown left. When the bulb is connected in circuit, electric current

pass through Filament Filament Filament Filament and it emits light.

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Sub-topic2: Conductor and Insulator

1. Touch things with disconnected cords.

And then, write down table shown as below

ExperimentExperimentExperimentExperiment 1111 Find materials which can lighFind materials which can lighFind materials which can lighFind materials which can light a disconnected circuit.t a disconnected circuit.t a disconnected circuit.t a disconnected circuit.

QuestionQuestionQuestionQuestion 1111

What kind of materials can link disconnected chords?

Disconnected circuit

MATERIALSMATERIALSMATERIALSMATERIALS

Various

Example

resultresultresultresult thingthingthingthing

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2. Organise results

3. Discussion: make conclusion from result

About: How is the difference between things which can link About: How is the difference between things which can link About: How is the difference between things which can link About: How is the difference between things which can link disconnected chorddisconnected chorddisconnected chorddisconnected chord and thinand thinand thinand things which cangs which cangs which cangs which can’’’’t t t t

link it?link it?link it?link it?

(If things link a disconnected circuit, a bulb in circuit would light. )

CCCConclusiononclusiononclusiononclusion

TTTThe feature of things which can link a disconnected circuit is he feature of things which can link a disconnected circuit is he feature of things which can link a disconnected circuit is he feature of things which can link a disconnected circuit is metal.metal.metal.metal.

((((IIIIron, aluminium, copper, etc)ron, aluminium, copper, etc)ron, aluminium, copper, etc)ron, aluminium, copper, etc)

Conductor When the metal link cords as a diagram shown left, electricity

pass through it.

Substances that allow electricity to pass along it or through it are

called conductorconductorconductorconductor

So, the metal is the conductor.

While things which can’t link a disconnected circuit are made of

plastic, wood or paper.

These substances don’t allow electricity pass through it.

These are called insulatorinsulatorinsulatorinsulator

Conductor andConductor andConductor andConductor and insulatorinsulatorinsulatorinsulator

Spoon (iron) Scissors (iron)

Coin Aluminium foil

Ruler (plastic)

Ruler (plastic) Ruler (plastic)

Board (wood) Bag (plastic)

Scissors (plastic)

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ExerciseExerciseExerciseExercise

1. Which is rubber band conductor or insulator?

2. Answer light or not for each of the following circuit.

Challenging exerciseChallenging exerciseChallenging exerciseChallenging exercise

Connections shown as below aren’t light. Explain why they aren’t light

Wood

a) b) c)

d) d) Challenging

a) b)

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1.1.1.1. EEEElectric Circuitlectric Circuitlectric Circuitlectric Circuit

If positive terminal and negative terminal are

connected, it’s light. This connection is called

electric circuitelectric circuitelectric circuitelectric circuit....

If positive terminal and negative terminal

are not connected, it’s not light.

And even, if circuit is breaking down, it’s

not light

2.2.2.2. ConductorConductorConductorConductor and insulatorand insulatorand insulatorand insulator

Stop electricity

If you link disconnected line by conductorconductorconductorconductor,

electricity pass through it and a bulb light.

If you link disconnected line by conductorconductorconductorconductor,

electricity pass through it and a bulb light.

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2cm

6cm 2cm

1. Cut a cardboard following diagram

shown as below

2. Wrap two piece of card board

in aluminium foil

3. Bend a long piece of cardboard 4. Cut a corrugated card box and staple

cord, two pieces and a piece of card

box.

4cm

6cm

HandicraftHandicraftHandicraftHandicraft

Make switchMake switchMake switchMake switch

Turn off Turn on

Switch