A = 0.0000000095
Finally, I put these figures in the equation to find out the amount of predicted resistance :-
0.000000017 x 0.2
0.0000000095
= 0.35789476 is the predicted resistance for a wire 0.2 metre long
0.000000017 x 0.4
0.0000000095
=0.715789473 is the predicted resistance for wire 0.4 metre long
0.000000017 x 0.6
0.0000000095
= 0.956482392 is the predicted resistance for wire 0.6 metre long
0.000000017 x 0.8
0.0000000095
= 1.269873157 is the predicted resistance for wire 0.8 metre long
0.000000017 x 0.8
0.0000000095
= 1.659872345 is the predicted resistance for wire 1 metre long
Apparatus
Used to generate electricity for the circuit
Used to measure the current in a circuit
Used to measure the voltage running in a circuit
Used to connect the circuit together
- Ruler with copper wire attached
Used so I can try all five lengths of wire in the experiment
Fair Test
To conduct the experiment I first had to make the experiment a fair test. I did this by keeping the power pack at the same voltage at all times. I also did not move or change any of the wires whilst conducting the experiment.
Method
Firstly, I set up the apparatus as shown in the above diagram. Secondly I switched on the power pack to run the electricity through the wires. Thirdly, I used the crocodile clips to make the length of the wire 0.2m long. I repeated this procedure changing the length of the wire to 0.4 m, 0.6 m, 0.8 m and 1.0 m. Next I recorded the current (amps) and voltage (volts) running through each of the lengths. To calculate the resistance of each length of wire in my experiment I divided the current (amps) by the voltage (volts). To ensure accuracy and reliability I repeated the experiment three times and noted the results. I also worked out the average resistance of each length.
Results
O.2 Metres
Average Resistance = 0.07
0.4 Metres
Average Resistance = 0.24
0.6 Metres
Average Resistance = 0.19
0.8 Metres
Average Resistance = 0.24
1.0 Metres
Average Resistance = 0.30
Conclusion
Based on the results noted above, my prediction was correct. The longer the wire the higher the resistance. This happened because when the wire was shorter the electrons had less to travel and there for did not take as long to give a reading of volts and amps. In addition, when the wire is shorter the electrons move quicker because they do not have as many atoms to push them down the wire.
Evaluation
In order to obtain a more reliable and accurate result I could have repeated the experiment a few more times. The experiment was also quite easy to set-up. I could have also made the experiment more accurate by using more precise equipment to provide better results. I could also have conducted the experiment by using more scientific equipment. This would have provided a more precise result. My results also differed from the predicted results considerably. This was because of the lack of precise equipment used. Whilst analyzing the results I did notice some abnormalities in the results. Some readings on the ammeter where very close for some lengths, this was shown on the ammeter readings for lengths 0.6 metres and 0.8 metres. The reliability of this experiment was also affected in the experiment. The wires used in the experiment where continually heating up therefore making the level of resistance decreases. If I had kept the wires continually at the same temperature, I would have got different results.
A further experiment I could do would be to see whether the diameter of a wire affects the level of resistance.
