In this experiment there are certain factors that will affect the accuracy of results, they are:
Temperature of the circuit, time taken to take measurement of voltage and amps, and length of the wire, type of wire, thickness of the wire. I will make sure, that out of these, I will keep the temperature of the circuit (do this in the same room, and since there is central heating, there should be a constant temperature), the time taken to take the measurements constant. The length of the wire, type of wire, and thickness of the wire are variable in this experiment. I have kept the temperature and time taken to take measurements constant because it will make my results more accurate, if the wire is hotter, then the resistance will go up, therefore making my results less accurate, and the longer time taken to take measurements, the more the wire heats up and stretches, making the resistance go up in two ways, therefore making my results inaccurate.
Conclusion:
My results obviously show that the relationship of the resistance and the length of the wire is directly proportional, the relation ship between the thickness of the wire and resistance is inversely proportional and NiChrome has more resistance than Maganin. These confirm my predictions. As I stated in my prediction, the reason why the length of the wire is directly proportional is because, if there if a longer path for the electrons to travel, more energy will be wasted and the electrons would move slower (less current), so the voltage must go up, because even though some of the energy will be transferred into heat, most of it can’t just disappear. Since V=IR or R=V/I, if the voltage increases and the current increases, then the resistance will obviously be more. The reason why the thickness of the wire and the resistance are inversely proportional is because if there was a thick wire, compared to a thinner wire, there could be more electrons in the wire, making more electrons go through the circuit (the amount of electrons passing thought the circuit per second is the current). So the current is increasing, this makes the voltage drop because there must be an equal balance to the energy used in the circuit, so since V=IR or R=V/I when the current goes up and the voltage goes down, and the resistance lowers. Seeing as I couldn’t find Maganin’s atomic number, I can only guess that the reason why it has less resistance is that it has more free electrons, therefore there will be more current going through the circuit and less voltage (the same as the thickness of the wire) and the resistance is then less than the NiChrome. The results show all of these things easily because you can see on the line graph, the lines of best fit arranged in steepness, steepest first are; Maganin 28 SWG, NiChrome 28 SWG and then NiChrome 30 SWG, and the mean for these wires, in the same order are 2.173629, 3.420038 and 5.044083. The averages also show that the thinner the wire, the higher the resistance and that Maganin has less resistance than NiChrome. The graph also shows that the length of the wire is directly proportional to the resistance by the positive correlating line of best fit.
Evaluation:
I think that my method was a good way to carry out the experiment, there could be better ways of doing so, but this would take a lot of equipment. I think my results were fairly accurate because each reading was repeated three times and I would say that they are definitely good results to make a firm statement about my conclusions, and that anybody else who tries this test will come to the same conclusions as I have. There were a few anomalous results; they have been taken out of the averages. I can explain each one of these with what I believe to be the cause of them:
(1), (2), (3) Were most likely errors in equipment because they were 3 consecutive errors, or the wires were hotter than usual
(4) This was most like a human error, writing down the wrong number
(5) This was most likely equipment error, because there is no real reason why it should be higher
(6) This was most likely caused by an equipment error or the wires were hot or the time taken to write down results was more
(7) This was most likely caused by an equipment error or the wires were hot or the time taken to write down results was more
My experiment worked pretty well, except the fact that I didn’t do exactly as I planned, an only did up to 60 cm on the NiChrome and I only started on 10 cm on the Maganin. If I was to do this experiment again, I would repeat all of the measurements 10 times, so that I could get a definite conclusion. I think I have a wide enough range, and enough measurements in that range, but I would like to have an airtight room kept at a zero degrees so that the temperature will be the same and I would definitely like perfectly accurate equipment, and a power pack that I know always outputs the same voltage constantly.