To study the resistance or wire we experimented on changing the length of nichrome wire. We measured the volts and amps over 1 metre; I worked out the resistance using my calculator. We carried out this experiment 5 times to make the results fair. We let the wire cool down a bit between doing the experiments, as its temperature did tend to increase as we got to the end of each experiment.
Analysis
We took a set of practice results before starting the experiment. Here they are.
Here are the results that our group received in order.
These are the averages for all five sets of results.
Here is a bar chart for the averages table.
Here is a line graph showing the results of the averages. The black lines in the graph are the lines of best fit.
As I increased the length of wire the resistance increased at a higher gradient than the current decreased, this is because the difference between each set of results of Ohm is far more than the difference between each set of results of Amps .The lines of resistance is more of a straight line than the lines of voltage and current, they are curved.
There is no significant pattern of results, and there is not much difference between all of the sets. This shows that our experiment was very accurate and a fair test.
These results and graphs have shown that what I predicted was correct. As the distance of the wire increased the resistance increased and the current decreased.
Evaluation
The results that I have obtained have been very repeatable. The 20 and 100cm length showed the most variation in the voltage. The 20cm length showed the most variation in the current. And the 60cm length showed the most variation in resistance. There seemed to be a lot more variation in the resistance results than in the others. There were no major anomalies in the results.
We carried out our experiment very fairly and I think that we have obtained the most accurate results in the time that we were given. Our method was to let the wire have a cool down before we went on to collect the next series of results, this should have made the experiment even more accurate. To improve and make our results more reliable we could carry the experiment out more that 5 times. If we had more time we could also make sure the wire is at its original heat before starting on the next experiment.
To carry out further investigation I would change the type of wire to constantan and carry out the same experiment using the same measurements. I would compare the results and see what differences would occur. I would expect that the resistance would be higher on one of the types of wire but I am unsure which. on one of the types of wire it would be. It depends how much electricity they are able to conduct. on one of the types of wire but I am unsure which. It depends how much electricity they are able to conduct.
