When the wire increased in length, the more current was required, therefore decreasing the current speed and increasing the resistance. When electrons were in the circuit, they were forever losing energy. While going through a longer wire and longer circuit then the electrons will lose energy and more will have to be sent, creating yet more resistance. As you can see, there are a couple of points that prevent the graph being a smooth line, notably, at 30cm and 60cm. The reason of this could be due to the wire not being measured out properly or possibly by misreading the ammeter and voltmeter.
My prediction was therefore correct, saying that the longest wire would have the greatest resistance. EVALUATION In conclusion to the investigation, I can say that, in my opinion I had insufficient data in order to analyse and get an accurate graph towards my aim. If I tested again, I would maybe do 25 tests instead of 3, giving me an accurate answer and hopefully a more exact straight line on my graph. My results may also have been inaccurate due to the possible misreading of the ammeter and voltmeter, at the shorter lengths of wire we needed to switch the circuit on and off very quickly to prevent the wire from melting.
If I did the investigation again, I wouldnt be able to use a resistor, which would defeat the point of the experiment. Im not sure how Id tackle this problem. I could also have used a digital voltmeter instead of an analogue one because the analogue one would be a lot less accurate than a digital one. I feel the analogue one is less accurate because I would have had to read the meter manually with my whereas a digital one would have given a much more detailed reading.
I could also change a variable, which would see the problem from a different perspective; I could look at the thickness of the wire or the voltage at which the power pack is set. This would give me more data to work with, on top of the set of results in this experiment. In conclusion, I feel this experiment was quite successful although more tests mean a more accurate result. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.