• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month
Page
1. 1
1
2. 2
2
3. 3
3
4. 4
4
5. 5
5
6. 6
6
7. 7
7
8. 8
8
9. 9
9
10. 10
10
11. 11
11
12. 12
12
13. 13
13
14. 14
14
15. 15
15

# Resistance of wires.

Extracts from this document...

Introduction

Resistance of wires

Matthew Hampton

11L

Physics coursework.

Planning My Investigation

Scientific Knowledge and Background

Metals are made up of metal atoms. Metal atoms bound to other metal atoms in a piece of metal or metallic bonding holds an alloy together. This type of bonding is different from atoms in covalent or ionic bonding as in metallic bonding the atoms do not hold onto their electrons strongly, in fact the atoms share the electrons in a sea of electrons, where they are free to move about and are not fixed to one particular atomic nucleus. This is the reason that metals can conduct electricity so well.

Ohm’s law: Experiments show that for metallic conductors, so long as their temperature does not change, V/I always has the same value when V (voltage, measured in volts) is varied and the corresponding value of I (current, measured in amps) is found. That is, the resistance of a metallic conductor is constant whatever the voltage applied. Hence V/I is a constant. This means, for example, that doubling V doubles I, and so on.

The current through a metallic conductor is directly proportional to the potential difference across its ends if the temperature and other physical conditions are constant.

Current is the flow of electrons round a complete circuit. Voltage is the driving force that pushes the current round. Resistance is anything in the circuit that slows the flow down. If you increase the voltage then more current will flow and if you increase the resistance then less current will flow.

Middle

Prediction

I predict that as the length of wire tested in the circuit gets longer, so the calculated resistance will increase. I also predict that the relationship between length and resistance will be a straight line with a 45-degree angle, so that when the wire length increases by a factor of 2, so the resistance will double. This is because I think the unit resistance of Constantan wire is constant, as long as all other variables except length are kept the same.

Apparatus used:

## Voltmeter

Amp meter

Wires

Power pack

Crocodile clips

Constantan wire

Cellotape

Metre rule

Scissors

Exercise book to record results in

#### Circuit Diagram

Method

I constructed a circuit as shown in the diagram above, using the apparatus listed above. The variable in the circuit was the length of the piece of wire, and I measured the length of the piece of wire used, the voltage and the current flowing through the circuit during each experiment. The piece of Constantan wire was laid along a ruler. A crocodile clip was placed at 0cm and the length of wire to be included in the circuit was determined by connecting a crocodile clip to the wire at exactly the correct place. The voltage was set at 4 volts. The voltmeter was connected in parallel to the wire and the ammeter in series. From the voltage and amps reading I calculated the resistance of the piece of wire. I performed each experiment three times, using 8 different lengths of measured wire. I averaged the results for each length of wire to increase the reliability of the results. I then plotted a graph of my results.

Conclusion

I do not feel that I could have improved the method or the equipment for this experiment and that the results obtained were accurate and reliable. The experiment was fair and safe. The results obtained were completely in keeping with both my prediction and the outcome I expected from my reading of background information and scientific theory.

Although my experiment proves that there is resistance in wires there are also other experiments that could be done to learn about the resistance of wires, for example, a ‘Micrometer screw gauge’ this measures very small lengths such as the diameter of a wire. So the thickness of wire could be tested to learn about the resistance in wires.

Also I could test all the factors mentioned in the planning of my investigation such as the temperature and the Chemical composition of the wire. I could use several different types of wires and I could use different temperatures of wires to see if those factors affect the resistance of wire.

Even though I haven’t done these experiments for the different factors I would expect the same results and the same out come proving that Wires have resistance.

To gather my information I used ‘ Physics for today and tomorrow’ by Tom Duncan

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

## Found what you're looking for?

• Start learning 29% faster today
• 150,000+ documents available
• Just £6.99 a month

Not the one? Search for your essay title...
• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month

# Related GCSE Electricity and Magnetism essays

1. ## In this coursework, I will be analyzing and proving that although metallic conductors are ...

3 star(s)

This is resistance. Resistance in general in electrons, is the obstruction, or collisions faced by the electron. In order to find out how, much resistance, there is, we use ohm's law. Ohm's law states that the amount of current flowing in a circuit made up of pure resistances is directly

2. ## Investigation in resistance in wires

5 star(s)

- The wire not being straight therefore it being hard to measure the length. - Measuring the wire length with precision. For the preliminary I decided to choose 3 different lengths because I had limited time available, the lengths would be separated by 2cm, and then I decided to do 9 different Voltages separated by 1 Volt.

1. ## Investigate the relationship between the length of wire and its resistance when a voltage ...

The length of the wire will start off to be 100cm (1m) and then decrease every 10cm down to 20cm. Electrons have a longer distance to travel so there will be more collisions at the beginning and then will reduce, when the wire shortens.

2. ## Investigate the resistance of different wires and how at different lengths the voltage increases ...

I can obtain more results with four different types of wire which will then help me to get a better set of results by comparing and contrasting the results. I will also need a Metre ruler stick - I will be using a 1meter (100cm)

1. ## Resistance of a Wire Investigation

plants while chlorophyll c, d, and e are present only in algae. Photosynthesis is the process of converting light energy into chemical energy which can only be performed by plants. All life on earth depends upon the ability of plants to photosynthesise simple sugars which are the basic source of food from which all other forms of food originate.

2. ## Investigate one or more factors affecting the resistance of metal wires

One way in which I could make the current the same would be to change the voltage on the power pack. I did this, and though it enabled me to get the same current, I noticed another problem. When I was trying to find the correct voltage to match the

1. ## An in Investigation into the Resistance of a Wire.

Diagram = Main power supply = variable resistor = Multi meter = wire = Multi meter = crocodile clip Apparatus The apparatus that I will need to do this experiment are: * 2 Multi Meters * 7 Wires * 2 Crocodile clips * Power pack * Rheostat (variable resistor)

2. ## Resistance of wires

Another way to work out the many different calculations in physics is to use this excellent diagram, also discovered by George Ohm. (I extracted it from a physics website In this useful and valuable formula grid, George Ohm exposed how to calculate and work out different equations to be applied

• Over 160,000 pieces
of student written work
• Annotated by
experienced teachers
• Ideas and feedback to