What variables affect the resistance of a piece of wire?

Safety: -

• Make sure all wires and components in the circuit are connected properly to avoid resulting in short circuits.
• Keep the circuit well away from any water.
• Don’t overload the ammeter and voltmeter.

Fair Test: -

To make the test fair, the same equipment in the circuit will be used each time any recording is taken. The recordings will be taken with values to two decimal places each time.

OBTAINING EVIDENCE

Results: -

ANALYSIS AND EVALUATION

Conclusion: -

The results prove that as the wire length increases by two times, so does the resistance. This agrees with the prediction made earlier, as the electrons travelling through the wire have a higher chance of colliding with the wire’s particles thus stopping the natural flow of current.

Evaluation: -

The graph plotted represented how the length of a wire affects the resistance. No anomalous results were brought up, and so a line of best fit was easy to plot each time. The length of the wire is directly proportional to the resistance.

To ensure further accuracy, there are certain things that could be changed in order to obtain better results:

• Take a wider set of results. Possibly twice as many, then work out the average.

• To further experiment on what factors affect the resistance of a wire, I could have tested the three other variables – the cross-section, the material and the temperature.

• The experiment could have been carried in a controlled environment, allowing the temperature to remain constant and allow a fairer test.

• The wires used in the circuit contain a certain resistance, therefore certain wires with less resistance could have been used.

Information for this coursework was taken from Encarta ’98, Physics Matters by Nick England,  and GCSE Physics by Richard Parsons.