We have chosen to do the lengths of the wire because it will be easy to carry out and our results should be very accurate for the simplicity of this experiment.
Prediction- My prediction is that the shorter the wire the lower the resistance.
Equipment-
- Wire
- Crocodile clips
- Ruler
- Ammeter
- Voltmeter
- Power pack
Method- In our experiment we will use 1 metre of nickel chrome wire. We will attach the wire to a metre ruler and then we will create a circuit-
When we have our circuit made we will attach a crocodile clip to the 90cm mark measure the voltage and current, we will then move it down 10cm and repeat.
Our range will go from 90-10cm. We will repeat each result twice and find the averages.
When we have the average current and voltage we will find the resistance using the formula- Voltage / Current = Resistance (Ohms)
Safety- We will keep the power pack on four so we can get good results and not burn the wire.
Analysis- I found out that the length of the wire does affect the resistance of a wire because as the length gets shorter the amps rise while the voltage falls
We used the calculation V / I = Ohms to get our results as shown in the table above.
Our results show that as the length gets shorter the voltage gets smaller this shows that as the length gets smaller the resistance drops. This is because there are fewer molecules to hit so there will be less resistance.
My prediction was justified because I have proven that the shorter the wire the less resistance.
Evaluation- I think I did very well on the experiment because all the results in green were sort of anomalies because we changed our wire and power pack, which would, gives alternative readings to our other results.
We could improve the experiment by using the same wires and power pack for the whole experiment.
The worst anomaly, which is furthest from the line of best fit, is labelled in blue in the table above.
Secondary Data
This secondary data shows that the longer the wire the higher the resistance thus my evaluation is valid. These results are very good as the line of best fit goes through all the points on my graph. There is one anomaly, which is labelled in green, which is 0.2 Ohms off the rest of the points. This can be proven because each time the resistance goes down by 5 and then it goes down 5.2 Ohms.
