An Investigation into Finding the Different Values of Resistance with Different Lengths of Wire.

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Name: Luke Smallwood                                   

Group: 10J3


An Investigation into Finding the Different Values of Resistance with Different Lengths of Wire




In this experiment I intend to find out what happens to the resistance of a wire, when we increase or decrease the length of the wire.


Input Variables:

  • Length of tested wire.

Output Variables:

  • Ammeter reading and voltmeter reading.

Controlled Variables:

  • The tested wire,
  • Power supply,
  • The leads connecting the components together,
  • The ammeter and voltmeter.
  • The resistor


 I predict that in this experiment the results will show us that the longer the wire the more resistance the wire will have, and that if the wire doubles in length, the resistance will double. I also predict that the results graph will look similar to the one below:

Scientific Knowledge

         I have predicted this outcome for my experiment due to the scientific knowledge that I have obtained. I predicted that the longer the wire the more resistance there would be, because when a voltage is applied across the wire, it causes the electrons to move creating a flow of current.  When an electron collides with atomic nuclei, it looses its energy and this is called resistance.

Therefore the longer the length of wire the more atoms there are for the electrons to collide into so therefore there will be more resistance and so that is why I have predicted that the double the amount of wire, the double amount of resistance there will be, as there will be double the amount of atoms, so therefore there will be double the amount of resistance.


       In this experiment there are few but important safety issues to consider and are the following:

  • Not to touch the wire as when current flows through the wire, the wire may become hot.
  • Not to touch the electricity.
  • Make sure the wire is coated completely in plastic so as to reduce the chances of an electrical shock.
  • Do not have any liquid, such as water, when carrying put the experiment, as this will offer a greater chance of any kind of electrical shock.
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Fair Test

In order to make my experiment fair I will keep the following factors the same:

  • The thickness of the wire constant throughout the experiment as different thickness’ of wire will offers different routes for the current to flow through so will alter the results.  
  • Use the same wire during the experiment as different wires, of even the same thickness, will offer different resistance, due to different amount of atoms within the wire and may offer different resistance between two wires the same lengths because they could have different atom constellation so will offer different ...

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