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textbook for G7 in PNG. English is not mother language in PNG. So, not only wrinting but also diagram should be used. And, learning should be done as step by step. I think the first step is very imporatnt.
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1
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
5
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
6
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.
8
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
9
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)
10
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)
11
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.
12
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
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