We did preliminary tests to ensure that the wire did not get too hot, If the wire got too hot, energy would be given off as heat.
The circuit should be set up as in the circuit diagram. It is important that the voltmeter is set up in parallel and the ammeter in series. The readings from the ammeter and voltmeter will be used to work out the resistance.
Hypothesis: many different things can effect the resistance of a wire.
Diameter: A small diameter will have a small surface area creating more resistance. A large diameter will allow the current to pass more freely with less resistance.
Length: The of the wire will also affect the resistance. If the wire is long their will be a higher resistance because their will be more particles for the current to pass.
Fair Test: To ensure that the investigation is carried out in a fair way and that the results will be accurate and reliable a number of things must be followed. The only variable in the test will be the length of the wire. The wire must be pulled tight against the ruler and taped in place to ensure the length is accurately measured. The same circuit and battery must be used throughout as different batteries may have different voltages if they are old.
Equipment:
Power Pack
Voltmeter
Ammeter
wires
crocodile clips
Ruler
Coin
Input Variable: The length of the wire
Output Variable: Voltage
Method: Firstly we gathered the equipment together and set up the circuit making sure Voltmeter is set up parallel and the ammeter is in series. Then we set up the meter ruler using a coin as a switch. Then we recorded our result every 10cm recording the resistance.
Safety: This experiment was not very dangerous but every experiment must have safety. The only precaution was to make sure that the voltage was not to high so that it started to burn the wires.
Evaluation: The experiment proved to be a success and it went very well although it could be improved by trying other lengths of wires to get a more varied results. Also the equipment we used was very old and if we were to do the experiment with new equipment I think the results would be very different.
Conclusion: My results support my prediction and the hypothesis in that the longer the wire the more resistance and the shorter the wire the less resistance. Also my graph results show a clear relationship between the length of the wire and the resistance. A steady increase of resistance every 10cm.
