Resistance Investigation

The Thickness: Thicker wire could contain more atoms, therefore there is more free electrons to carry the electricity than the thinner wires. This again is similar to the situation of road works.

The Temperature: When the temperature of the metal increases, the atoms move and vibrate more. These vibrations can block the flow of electrons than a cooler wire. So the higher the temperature the greater the resistance.

Prediction: I predict that the greater the length the greater amount resistance there will be.

Diagram Of Apparatus

Method

* Set up apparatus as shown in the diagram above

* Turn ammeter on

* Place crocodile clips apart on resistance wire

* Turn power supply on

* Read and record from the Ammeter

* Turn power supply off.

* Repeat above instructions for

* Repeat whole experiment again to get average results

* Calculate Resistance using formula:

Fair Testing

* The wire must be kink free so there are no loops therefore there are no short circuits.

* Do not have the power supply on for too long, otherwise it will overheat the resistance wire

* Have the power supply on for roughly the same time to keep the test fair

* Accurate reading of the resistance wire

* Always keep the voltage the same

* The wire mustn't be too small, otherwise it will over heat and melt.

* Must use the same piece of wire to keep the test fair.

* Visually check that the wire looks the same thickness

Results Table

Analysis.

My graph is directly proportional and the line of best fit is going through the origin. My prediction was right; I predict that the greater the length the greater amount resistance there will be.

Evaluation

I found the investigation very easy to carry out. The only difficult was to keep the resistance wire straight so there would be no short circuits; we solved this by having a partner holding the wire flat we placed the crocodile clips.

We did not have the power supply on for too long, otherwise it will overheat the resistance wire

We had the power supply on for roughly the same time to keep the test fair

We always kept the voltage the same to keep it a fair test.

The wire wasn't too short, we started at so that we did not overheat and melt the wire.

We used the same piece of wire to keep the test fair.

I personally think that the accuracy of the observations were accurate, the repeat readings were very similar to each-other and were very close to the line of best fit!

To improve the investigation, we could carry out other investigations to back up my prediction such as a different voltage, longer lengths of the wire and also different wire such as Nicron wire