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Changing the length of a wire and how it affects the resistanc - GCSE Coursework

Extracts from this document...

Introduction

Physics Coursework – Changing the length of a wire and how it affects the resistance

Aim – I want to find out if the change in a length of wire affects the wires resistance and what type of wire gives the best results to work with.

Prediction – I predict that when the length increases, so will the resistance. I think this because the longer the wire, the more energy the electrons use up when they go around the circuit. Because the voltage will stay the same, more energy will have to be used up with an increased length.

I think this is what my graph will look like. The line of best fit will help me achieve this.

Scientific Knowledge –

What is resistance? –

An electric current flows when the electrons move through a wire. This wire is a conductor and contains atoms that the electrons can collide with. When the electrons collide with the conductor’s own particles resistance is created.

...read more.

Middle

0.6

0.65

2.70

3.89

0.4

0.91

2.48

2.69

0.2

1.68

2.19

1.32

Here are the results from my preliminary experiment together on one graph so I can compare which is best.

The Resistance of 3 different wires:

When I did my preliminary I decided to choose constantan wire. I chose this because it gave me the best range of results and the easiest results to work with.

My Main Experiment - Now I have tested the experiment in my preliminary experiment I can use things I have learnt to improve my next experiment.

Method –

  1. First I need to collect all the equipment and prepare my work surface. I need to set the circuit out as below:
  1. When the power pack is plugged in, I need to turn it on and set the voltage. I then need to attach the wire so the crocodile clips are attached at the length of 0.2m
  1. Once the wire is attached at 0.2m I need to run the power through. I then need to write down the voltage and the amps onto my results table.
  1. Once I’ve written down my first results I need to repeat it so I have 3 different results. This means I can create an average current and average voltage to achieve the best results.
  1. I can then repeat steps 2 onwards for the next measurement (0.4m) until I have all the results for all the lengths of wire.

My results from the main experiment are as follows:

Length (m)

Current (amps)

Aver. Current

Voltage

Resistance ()

1

2

3

4

5

2

0.72

0.75

0.69

0.74

0.73

0.73

2.22

13.04

1.8

0.23

0.22

0.23

0.23

0.22

0.22

2.62

11.19

1.6

0.26

0.25

0.25

0.26

0.26

0.26

2.63

10.12

1.4

0.28

0.29

0.28

0.28

0.28

0.28

2.54

9.07

1.2

0.33

0.33

0.33

0.33

0.32

0.33

2.53

7.67

1.0

0.39

0.39

0.39

0.39

0.39

0.39

2.51

6.44

0.8

0.47

0.46

0.48

0.47

0.48

0.47

2.44

5.19

0.6

0.62

0.62

0.61

0.62

0.62

0.62

2.34

3.77

0.4

0.86

0.88

0.89

0.89

0.89

0.88

2.26

2.57

0.2

1.50

1.48

1.46

1.45

1.39

1.46

1.82

1.25

...read more.

Conclusion

There were no anomalies in my results as they all followed the line of best fit.

My results followed a pattern. The pattern was that the lowest lengths had the lowest resistance and the higher lengths had a much higher resistance. I predicted that when the length of the wire increased, so would the resistance. I thought that because the longer the wire, the more energy the electrons use up when they go around the circuit.

Evaluation - The method I used I thought was effective because the circuit was easy to change the length of the wire (simply by re-clipping the crocodile clip to make it shorter) My results are quite precise and accurate and there were no anomalies so I think I that the experiment when according to plan. I followed through my method accurately and produced accurate results.

...read more.

This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.

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