1002 words - 4 pages

PlanIn this investigation I am going to investigate how the length of a piece of wire affects its resistance. The following are all variables that affect the resistance of the wire:- The thickness of the wire is a big variable as the thinner the wire the bigger the resistance. This is because the current has to squeeze through a thin wire, but it can easily flow through a thicker one.- The length of the wire is also a big variable as the longer the wire the more atoms the electrons will hit making it a bigger resistance.- The temperature of the wire effects the resistance because as it gets hotter the atoms inside it vibrate more which increases the chance of the electrons hitting them so the hotter it gets the more resistance it has.- The type of wire can also affect the resistance because different metals have different amounts of free electrons and the more the smaller the resistance is.These variables will all effect my investigation but I am going to use the length of the wire as the variable and keep the others the same to make it a fare test.I predict that the longer the piece of wire, the greater the resistance will be. This is due to the idea of the free moving electrons being resisted by the atoms in the wire. In a longer piece of wire, there would be more atoms for the electrons to collide with and so the resistance would be greater. The relationship between the wire length and the resistance should be directly proportional. This is because in a wire twice the length of another wire there would be double the amount of atoms causing the resistance.An example of this would be in a 20cm wire. The electrons would have to travel double to distance if it has to go through a 10cm wire. This would in turn double the amount of atoms that the electrons would collide with and then resistance would double.I will need the following apparatus; a meter ruler with wire taped on it, a voltmeter, an ammeter, some wires, a power pack and two crocodile clips.In this investigation I will measure the resistance of the voltage and the amps so that I can times them together to get the resistance. I will do this at 20 centimetre intervals. To make it a fair test I will do one at least three times and find the averages. The only variable in the test will be the length of the wire. The wire must be pulled tight against the ruler and taped in place to ensure the length is accurately measured. The same circuit must be used throughout.Method:Firstly I will set up my apparatus as shown in the diagram above. Then I will measure the voltage and the amps at 20 cm intervals. I will only have the wire connected in the circuit for a few seconds so that it does not heat up and effect the results. I will then...

Get inspired and start your paper now!