How does the Thickness of Wire Affect Resistance?
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How does the Thickness of Wire Affect Resistance? I have chosen to investigate the effect thickness will have on the resistance in wire. Apparatus * Wires of varying thickness * Power pack * Leads * A voltmeter * An ammeter * Crocodile clips Prediction I predict that the thicker the wire, the lesser the amount of resistance. This is because as electrons pass through a circuit, they give off heat. The surrounding atoms use this heat as energy, which causes them to vibrate. As the electrons give off more energy, the atoms vibrate more, making it harder to allow the electrons to get through the wire. Therefore, a thinner piece of wire will create more resistance (because there is less space for the electrons to get though). See the diagram below for more explanation. Method 1) Set up the apparatus listed above. 2) Set voltmeter and ammeter to correct settings.
I will not touch the wire whilst the power pack is on, as it will become very hot during the experiment. The exposed wire must not touch any surface at any point during the experiment or whilst it cools down afterwards. I will make sure this happens by using stands to keep the wire above ground level. Range * Wire - 0.18mm to 1.6mm, 1 meter long * Voltage - 3V to 12V * Repeat each test 3 times * Voltmeter set to 20 * Ammeter set to 20 Analysis The first graph, 'A Graph to Show the Difference in Current and Voltage in Different Thickness' of Wire' shows that the thicker the wire, the bigger the resistance. This was first discovered by G.S.Ohm, who created the law, I = V/R. This law is the basis of my first graph. It also proves that my prediction is correct, because the electrons do give energy to the surrounding atoms, so that as the voltage increases, so does the resistance.
Evaluation As I did my experiment 3 times I expect that my results were fairly accurate and reliable. To increase the accuracy of my experiment I also used the same length of wire each time, the voltmeter and ammeter at the same setting each time, and made sure that the wire was connected to the circuit in the same place during each experiment. The hardest part of the experiment is the calculation of results and the drawing of graphs, however I do not appear to have anomalous results. To improve my investigation I would try my circuit at a larger variety of voltages, as there are many gaps in my data and a clearer picture of the actual resistance needs to be achieved before I can make a more accurate analysis. I would also increase the number of thickness' of wire to use, as this would also increase the accuracy of my analysis. To extend my investigation further I would use several other different types of wire to see if resistivity was affected by the conductivity of the wire.
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