Investigating the resistance of a wire.

What might happen in my results

I think that when I do this experiment I will find that, the longer the piece of wire is, the higher the resistance will be.

Why might this happen?

I think that the longer the piece of wire, the more resistance will be let out because there will be more space for the electrons to have to travel through.

Apparatus

The apparatus I will use while completing this experiment are:

* 1 metre ruler

* Sellotape

* Connecting wires

* A Voltmeter (0-15V)

* An ammeter (0-5A)

* A battery (6V)

Diagram

Method

The first thing I did in this experiment was to collect the equipment I was going to use, I then taped the piece of wire to the metre ruler using a couple of strips of Sellotape. I then set the circuit up that was needed to make the experiment work. I connected the wire to the metre ruler at both ends of the wire. I connected one end of the wire to the voltmeter I was going to use and the other end of the wire to the ammeter I was going to use. I did this so I could collect the readings I needed to complete the experiment. I took the two readings for when there was 100m of wire. When I had taken these two readings, I moved one side of the ruler so the reading could be taken at 80cm. I repeated this three more times so I could take the readings for 60cm, 40cm, and then 20 cm. When I had taken these readings I repeated the experiment, I did this to make sure it was fair and I had two complete sets of results so I could find the average.

To make it a fair test I did not keep the wire connected to the voltmeter and the ammeter while I was recording my results. I did this so the wire would not heat up and they stayed at the same equal temperature through out the experiment.

Results

Length of wire

(mm)

Voltage (V) 1 dp

Current (A) 2 dp

Resistance (Ohms)

Attempt 1

Attempt 2

Attempt 1

Attempt 2

Attempt 1

Attempt 2

Average

20

0.6

0.5

0.87

0.58

0.69

0.86

0.78

40

.1

0.9

0.72

0.53

.53

.70

.62

60

.5

.2

0.66

0.52

2.35

2.31

2.33

80

.7

.6

0.56

0.48

3.04

3.33

3.19

00

.9

.9

0.53

0.46

3.58

4.13

3.86

Conclusion

I found out the longer the wire, the higher the resistance is. I said that was what I thought would happen. I did not state that when the length of wire goes up the current became less. I did not think that would happen.

There is a definite pattern in my results. When I worked out the average resistance I plotted the results on my graph. When I had drawn my line of best fit the line nearly includes each of the five points. This means that my results must be quite accurate.

Evaluation

I think that my results are quite reliable. When you look at my results table you can see that the results are very similar. I did the experiment twice so I could get a more reliable set of results. I think if I repeated the experiment I would possibly get the same results.