Gcse Physics Investigation: Resistance of a Wire.

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GCSE Physics Investigation: RESISTANCE of a wire.

Planning experimental procedures.

In this investigation, I will be looking at the factors that affect the resistance of a wire. I will select a variable and be sure to keep the other factors constant. I am looking for a pattern in the results and I will be looking at what causes it.

* As the length of the wire increases so the resistance increases.

* As the width of the wire increases the resistance decreases.

* As the temperature of the wire increases so does the resistance.

* Various wires have different resistance therefore the type of metal wire must be kept constant. (Nichrome)

* The higher the voltage travelling through the wire the more resistance is needed to prevent over heating. Therefore the higher the voltage, the less the resistance.

Variables

In this experiment one could alter:

* The thickness of the wire.

* The length of the wire. (I would measure this by using a meter rule.)

* The voltage across the wire. (I control this by using the dial on the battery pack.)

* The type of metal. (This is not suitable for use in this school.)

* The temperature. (I must be sure to only switch the battery on as needed otherwise the temperature will increase when I do not want it to.)

To keep the experiment a fair test, I must be sure only to change ONE of the variables, all the other factors must be kept constant. If I did not keep the other factors constant the results may be incorrect and there would not be any pattern.

Problems that may occur.

If I were testing how the thickness of the wire affects resistance and I altered the length of the wire each time I changed the thickness of the wire, the results would not be correct. I know that, as the length of a wire increases, the resistance of the wire increases. (If I did the experiment this way I would get results that showed this was true but would not be the correct results for what we are trying to find out.) However, if the length was kept constant throughout the experiment and only the thickness varied then the results would be correct because they would be showing that the greater the width, the less the resistance. (Which is what you needed to know.)
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Likewise, if I was testing the length of the wire and I changed the thickness of the wire each time I changed the length, the results would be incorrect.

As I know that various wires have varied resistance I must be sure to use the same type of wire each time. For example, copper wire is a good conductor and nichrome wire is an insulator therefore if I were to randomly choose a different wire each time and not be specific in which I was using the results would be wrong.

The higher the temperature of ...

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