Does Increasing the Length of a Nichrome Wire affect its Resistance

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Rob Brown                Science Coursework          

                

Does Increasing the Length of a Copper Wire affect its Resistance?

Prediction

I predict that as the length of the wire increases I think that the resistance will increase as well. To show this I will need to do an experiment to calculate the resistance using the figures from the Ammeter and Voltmeter at all 10 lengths to see if it does increase.

Current is the flow of electrons through a conductor. I will expect it to change in my experiment because as the current decreases the resistance will increase as well as there is more current needed to work against it if it moves in a longer piece of wire. Current is measured in Amperes or Amps (A or even I)

Voltage is the electric pressure or the potential difference that pushes the electrons around the circuit I would expect it to change in my experiment because it increases due to the greater force needed to push the current around the circuit. Voltage is measured in Volts (V). Also as the electrons make their way through the wire, they release energy. The voltmeter measures the energy in the wire. The longer the wire the more energy is transferred due to negative metal atoms collisions

When charged electrons in a conductor move around they will collide with the atoms of the conductor. This makes it harder for the current to flow around and causes Resistance. Electrons collide with atoms more often if they are in a longer wire than they do in a short wire because there is more space, so a thin wire and longer will have fewer electrons to carry the current than a thicker wire. This means the Resistance in a wire will increase as:

  • The length of the wire increases
  • The thickness of the wire decreases.

Resistance is measured in Ohms. (W)

Ohms Law

Ohms Law is a formula we would need to use to find the calculation for either:

  • Voltage, Current or Resistance.

We can express the formula like this,

V (Voltage) = I (Current) x R (Resistance)

I (Current) = V (Voltage) / R (Resistance)

R (Resistance) = V (Voltage) / I (Current

         

Copper Wire is a good conductor of electricity this because it allows electrons to pass through it. This is due to the metallic structure of the wire.

Using this metallic structure of a wire I can say that it will affect the wires ability to conduct as it gets longer in length because as it increases in length there are more metal atoms which the electrons will have to get pass which therefore means more collisions will take place causing the electrons to slow down even more and the current reading to decrease.

Every time an electron bumps into a metal atom, energy is released into the wire, you can measure this energy release by using a voltmeter. Therefore saying the bigger the number of collisions the bigger the energy release so the bigger the volt reading, this is why if you increase the length of wire the voltage will increase, the current will decrease and the resistance will increase as well.

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For each length of wire I will collect data for I expect to find out that current and voltage will obey ohms law. Looking at my predicted graphs I would expect to see an upward trend on the line which will show a direct relationship between resistance and length as the line goes straight through 0. The steeper the line the higher the gradient. The gradient of these lines = Resistance. Each length of wire should follow Ohms law as Nichrome is a good conductor and the wire should not overheat causing a deviation from ohms law

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I plan to calculate the gradients of each line. As the length increases, the value for gradient will increase. The gradient = the resistance of the wire.

Diagram

                 

                      Meterstick with

                        Copper wire

Equipment

I am going to use the following equipment for my Investigation:

  • A piece ...

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