Electricity Practical

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4

Glows red hot

Conducts doesn’t get hot

Heats up and melts

Electric fire

Conducting wires

Safety fuse

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Topic 7 page 26, 27

1.5 V

6 V

12 V

dim

brighter

bright

When the voltage increases the current

increases

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Topic 7 page 28

5. Write down your ideas.

The more batteries the brighter the bulb

This holds true as long as the batteries face the same way

If batteries are reversed they cancel each other out

Elephant handout

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Topic 7 page 29

Text

Animation 1

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Title:

Aim:

Method:

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Choosing the best type of cable

To compare copper/nichrome, thick/thin, long/short wires and find the best

Test thick and thin wires in a circuit and measure how it affects the current using an ammeter. Then test copper/nichrome and long/short wires.

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Topic 7 page 30

Diagram:

Results:

A bulb may be used instead of an ammeter

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Conclusion:

Short wires are better than long wires.

Copper wires are better than nichrome wires.

Thick wires are better than thin wires.

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Copper has a resistance than nichrome

Thin wires have resistance than thick ones

Longer wires have resistance than short ones

lower

higher

higher

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The variable resistor

4. Write down what you found out.

The longer the wire (coil) the dimmer the bulb, the shorter the wire the brighter the bulb.

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The variable resistor

Write down what you found out.

The longer the wire (coil) the smaller the current and the dimmer the bulb.

The longer wire has a higher resistance.

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A long thin nichrome wire has a higher resistance because

a) Thick copper wires are good for carrying current because

b) Long thin coils of nichrome are used in electric fires because

Topic 7 page 35

thick has a lower resistance, as does copper and short wires.