Reliability-
To make sure I achieve the most reliable and accurate readings from the amp and voltmeters, I will always repeat each wire three time- therefore getting the most reliable result possible.
Accuracy-
I will make sure I will get extremely accurate results by having one person in my group taking the ammeter reading, and another person taking the voltmeter reading, therefore getting the most accurate findings. I will take these readings three times, and find the average result. I will also round my findings to nearest number.
Safety-
Whilst doing the investigation, it is important to keep safety into consideration. During this investigation I will be using electricity, so I will have to be careful and use all the usual safety rule. Also, there will be a live wire in the circuit, so I must make sure I do not touch it.
Preliminary Experiment – Results
Prediction for final experiment-
From my Preliminary experiment you can clearly see that as the thickness increases, the resistance decreases. Therefore, I believe that in my final investigation, the results will be extremely similar, the thinner the wire the higher the resistance. The thinner the wire is the less channels of electrons in the wire for current to flow, so the energy is not spread out as much, so the resistance will be higher.
Final Experiment Results
Conclusion-
From my results you can clearly see a pattern, as the wire got thinner the resistance got higher. This is because the thickness of a wire affects the resistance because of the amount of space for movement it has and how many particles to pass it on e.g. If there was a thin wire and a thick wire than the thin wire would have the most resistance because there is less space for the electrons to move through. A quote from “ask jeeves” defines this clearly, “if you tried going through a tunnel ½ a meter wide you would find it harder than going through a tunnel 1 metre wide.” My above results show this clearly, although there is a big thickness jump from 34 to 40 SWG, the remaining findings are accurate and precise, giving us a good idea of how thickness actually effects resistance. Below is a diagram of my result -
Therefore, my experiment showed as the thickness of the wire increased, the resistance decreased.
Evaluation –
Overall I think my experiment went very well, as my results show a clear pattern and there were no ‘odd’ looking findings. Although we did not have such a big range of results as I was hoping for (a large gap from 34 to 40 SWG), you are still able to develop a good understanding of the effects. Also, my results may be inaccurate as it was difficult to cut the wire to exactly 10 cm, and then clip it to the ‘crocodile’ wires, although the majority were quite correct. Another problem, which could make my result imprecise, is temperature. As we found the wires produced a lot of heat, even causing the wire to glow and burn – especially on the thinner wires. This is because a higher resistance, the less the current flowing through – reducing the heat.
Also, as we had to take three recordings, the time between each result was different, so if I had the chance to repeat this experiment I would use a time-watch to get more precise readings.
If I had the chance to repeat this experiment, I would cut the wire more accurately before the investigation began.
Overall, I feel that I experiment went very well and I am extremely pleased with my findings and results.
