In this piece of coursework, I am going to investigate what affects the resistance of a piece of wire. Wire is made up of atoms.
Electric current is a flow of electrons, and it is these electrons that collide with the nucleus of the atoms. Every time this happens, it causes resistance. The build up of friction is what produces the heat.
There are many variables that could affect the resistance of the piece of wire:
Length
Potential difference
Tension
Temperature
Diameter
Shape
Material of the wire
I have chosen to do length because I think this will give me the biggest range of results. My prediction is-
The longer the wire, the higher the resistance
I think my prediction will be correct because the longer the wire gets, the more atoms there are for the electrons to pass. This means they have more chance of colliding, which will make it harder for the current to flow.
I also think that the length of the wire and the resistance may be proportional and that if the length of the wire doubles, the resistance will also double. This is because if the wire was twice as long it would have twice as many atoms for the electrons to collide with making it twice as hard for the current to flow.
To see if my prediction is correct, I am going to do an experiment.
(diagram) The ammeter will be connected in series- current flowing through the wire
The voltmeter will be connected in parallel- voltage (potential difference) across the wire
The crocodile clips make sure that only the certain amount of wire needed e.g. 10cm, is connected in the circuit.
I have already planned which measurements I am going to take for the length of the wire. I will start at 10cm, and then keep increasing the length by 10cm until I get to 90cm. This will give me 9 results which should give me a big enough range of results.
I will first set up my experiment (as shown in the diagram above). I will measure the