Am going to investigate some of the factors that may affect the resistance of a wire

Current

Current is defined as the flow of electrons being pushed out of the negative side of the cell/battery which is measured in amps. Current flows from the negative to the positive side of the cell/battery. Current can only flow round a circuit if it is complete, electrons are pushed out of the negative and drift slowly to the positive.

Voltage

Voltage is what makes the current flow, it is the potential difference between two points, one of the points is negative and the other is positive, if a charge is positive it will be attracted and flow to the negative point. If the charge is negative, it will be attracted and flow to the positive point, voltage is measured in volts.

Results

Resistance = Voltage / Current

Resistance per cm = Resistance / Length

1st test                                                        2nd test

Average result

Average = results added together divided by the number of results e.g. voltage 2.95 + 2.90 / 2

Conclusion

Overall I have found, during this investigation, that the connection between voltage and current is that the higher the current the lower the voltage, I’ve also found that, the connection between length and resistance, is that the longer the resistor, the higher the resistance. I have also found that the shorter the resistor the higher the resistance per cm. therefore if we were to have long power cables it would be dangerous for them to have high current as the high resistance would cause the cable to heat up, this could be a fire hazard.

Evaluation

I feel that my results are reliable because I repeated them to obtain an average result, however, I could have made them more reliable if I had repeated them more often. I don’t feel that this was a fair test, I feel this because it was very difficult to gain the correct measurement of the wire as it was coiled, I tried to gain a measurement by taping the wire to a ruler this was more successful, but still unreliable as the wire slipped through the tape.  If I were to do this practical again I would investigate better ways of holding the wire flat, also I would repeat the results more often as repetition equals reliability.