• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

To find out what happens to the resistance of a wire, when you change the length of the wire.

Extracts from this document...


Resistance Of Wire. Aim. To find out what happens to the resistance of a wire, when you change the length of the wire. Background Information. A current of electricity is the flow of negatively charged electrons around a circuit. [image001.gif] [image002.gif] [image002.gif] [image003.gif] [image003.gif] [image004.gif] [image005.gif] Close up, the wire and the electrons look like this: [image006.gif] The electrons collide with the atoms as they travel through. We say the atoms `oppose' the flow of electrons. This is called resistance, and the wire gets hotter. In 1826, Georg Ohm discovered that when a current flows through a metal wire the current and the potential differences are proportional, providing that the temperature remains constant. The resistance of wire can be calculated using: [image007.gif] Variables. Temperature increases the resistance as the atoms are getting hotter they are vibrating and moving faster. This makes the atoms and the electrons collide more. Thickness of wire decreases the resistance, as there is more room for the electrons to travel past the atoms. ...read more.


and attach them to a power pack, a voltmeter and an ammeter using crocodile clips. I will use one length of wire at a time. When I turn the power on, I will record the current and voltage quickly to 2d.p for accuracy. [image008.gif] Then I will work out the resistance using Ohms Law: [image009.gif] I will do this for all five measurements. I am using these measurements because my preliminary work gave me a good result when I tested them. I will repeat the tests three times to make sure that I get an reliable result. This way my results will be reliable. Results. Length of wire. Current (Amps) Voltage (Voltage) Resistance (Ohms) Average (Ohms) 10cm 0.17 0.01 17 17.5 10cm 0.18 0.01 18 10cm 0.19 0.08 2.374 20cm 0.22 0.01 22 21 20cm 0.21 0.08 2.625 20cm 0.20 0.01 20 30cm 0.01 0.20 20 21 30cm 0.03 0.21 7 30cm 0.01 0.22 22 40cm 0.01 0.18 18 20 40cm 0.01 0.22 22 40cm 0.01 0.21 2.625 50cm 0.01 0.22 22 21.5 50cm 0.01 0.21 21 50cm 0.04 0.20 5 Analysis. ...read more.


I could change this by increasing the length of the wire or keep lengths the same as before but use a different type of wire. My graph shows this. I have realised that the readings must have been wrong, but I would retest them. To make my results more accurate, I would repeat the experiment. I have enough evidence to reach a conclusion. My results match what other people have found. To additional evidence, I would do another experiment using the same measurements but different types of wire e.g. constaintin. I would do this because I could see if the two odd results became more accurate and because it is known to have a higher resistance than copper wire. To extend my investigation I could use lengths of wire over 50cm. Or, to test my work, I would use a different type of wire. This would change my results because every different types of wire have their own arrangement of atoms (obstacle course). ...read more.

The above preview is unformatted text

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

See related essaysSee related essays

Related GCSE Electricity and Magnetism essays

  1. To find out what happens to the efficiency of a motor as I change ...

    * Height (m): the height in meters that the load is lifted - always 0.5m. * Volts (V): the voltage taken from the voltmeter in the circuit. * Amps (A): the number of amps read from the ammeter in the circuit.

  2. To find out what happens to the resistance of a wire when you change ...

    Fair Test To make my experiment fair, I need to make sure the voltage across the wires is the same the wires are of the same type and that the temperature remains constant and the wires don't become too hot.

  1. A little bit about the life and times of Georg Simon Ohm:

    For example Voltage across wire in V Current through wire in A Voltage � current in ? 3.0 1.0 3 6.0 2.0 3 9.0 3.0 3 12.0 4.0 3 resistance = 3? Here, the Voltage and current are in proportion.

  2. Temperature of water using the change of resistance of a metal

    Looking at the equation, 'Resistance = resistivity x length/ area' it can be seen that the greater the value of the length, the higher the resistance. However the more resistance there is, the more the wire will heat up due to the current flowing through it which would affect the resistance.

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