Investigating factors which affect resistance in a conducting wire.

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Investigating factors which affect resistance in a conducting wire

The following experiment is to see what factors in circuits can affect the Resistance in a wire.

Resistance is what slows down electron particles and in this particular experiment it’s the current. There is specialist equipment that can do this and we are lucky enough to have this. Resistance happens mainly from the electrons moving in a negative direction, they then collide with the fixed particles (metal wire) and this slows them down from an easy flow through. You just have to look at it like it was a crowd of people standing still and others are trying to get through but are stopped and helped held up by the crowd. It reduces the current therefore increases the resistance. Kinetic energy also takes place within the wire + current. The kinetic energy, from the moving particles, transforms in to heat and this causes the heating effect. The energy is being given off by the particles is being converted to heat energy.

There are two main factors that effect resistance they are:

  1. Length
  2. Diameter (surface area)

Length increases resistance. This is because there are more collisions to be made because it is a longer journey, for the current to travel through the wire. The more collisions there are, then the less the current and the bigger the resistance.

Diameter decreases resistance. It does this by giving the electrons of the current more space to pass through the wire. Therefore creating less collisions and less resistance. The bigger the diameter the more space there is between each fixed particle the less collisions with electrons flowing through and less resistance!

Preliminary experiment:

For my preliminary experiment I decided to use length as my input variable. This was my choice because I predict that length increases the resistance, and I wanted to prove it. I will change the length by going down measuring with a metre stick a whole 1metre and going down 25cm each time as my range. My other variables are temperature and diameter. I will keep these the same by using room temperature and checking with a thermometer regularly, that it does not change. Also for diameter not to change I will use the same wire for every experiment. My outcome variable will be resistance. This will be calculated by doing this sum Voltage/potential difference (V)

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                        Current (A)

Prediction

In the preliminary the results are not as conclusive as would have been hoped but that’s where you can excel on testing. In the preliminary there were only three tests which were inconclusive, there needs to be a greater amount of tests to ensure a full set of results are obtained. It is also vital that different wires are tested as one wires result are sure to differ from that of another. In my experiment both Constantine and Manganin wire has been used. I feel that different sizes in the form of length and diameter both ...

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