These voltages prevent the wire from heating up, so all I need to do is keep the voltage below 1V each time.
I need to keep all of these the same to be sure of obtaining a reliable set of results, and a fair test. I am deliberately changing the length of the wire and the voltage to prevent the wire from heating. I decided to use six different values, from 10-60cm long wires. I think this is better as the difference between the highest and lowest is high. If the values had smaller differences, a mistake of 1mm in the measurement could make a huge difference, but it would not make as much difference in the values I am using. To make sure the results are reliable, I will repeat the experiment and work out an average between the two results I have. This is in case of an inaccurate result.
First of all, the resistance did increase as we increased the length of the wire. The results are almost on a straight line, so it seems that the resistance is directly proportional to the length of the wire. If the length is doubled, the resistance also doubles. The line of best fit does not go through the origin. It would be thought that no wire would have no resistance, but the crocodile clips and the connections would also have a resistance. Every point
lies almost exactly on the line of best fit, except the 30cm measurement, although it is only around 0.5Ω from it.
My original hypothesis was correct – the resistance increased with the length of the wire. This happened because of the amount of particles inside the wire that the flow of electrons will need to pass. In turn, there will be more collisions between the electrons and the atoms inside the wire. This is the resistance, and a higher resistance will mean more collisions between the free electrons in the current and the atoms inside the Constantine wire.
The results are accurate, as I used very small measurements (cm/mm) and left my results at two decimal places. If I had, for instance, used inches and rounded all of the results to one or no decimal places, the results would be far less precise. I can also tell that they are reliable as the graph makes an almost exact straight line. Had the results been all over the graph with a line of best fit far away from the points, I could not say this. I am very confident that my conclusion is right. This is because of the fact that the points lie on a straight line that is directly proportional to the y-axis. If the length is doubled, the resistance also doubles. To improve the reliability, I could repeat the experiment more than just once. If I had an average of three or four tests, I would have a far more accurate graph. Resistance is measured in ohms.
