The Resistance of a Wire

The Resistance of a Wire

Aim: To investigate how the length of the wire affects the resistance

of a wire.

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Introduction: Electricity is conducted through a conductor, in this

case wire, using free electrons. The number of free electrons depends

on the material, the more free electrons, the better the conductor.

For example, gold has more free electrons than iron and, this makes it

a better conductor. The free electrons are given energy, which make

them move and collide with other free electrons. This happens across

the length of the wire and causes electricity to be conducted.

Resistance is the result of energy loss as heat. It involves

collisions between the free electrons and the fixed particles of the

metal, other free electrons and impurities. These collisions convert

some of the energy that the free electrons are carrying into heat.

Secondary Sources:

· The Internet

· Text books

· Information from class

Prediction: I predict that the longer the wire, the higher the

resistance. This is because the longer the wire is, the more times the

free electrons will collide with other free electrons and the

particles making up the metal. This means that more heat energy is

going to be lost in these collisions. I also think that if you double

the length of the wire, you will get double the resistance. This is

because if you double the length of the wire you are also doubling the

collisions that will occur, doubling the amount of energy lost in the

collisions.

Preliminary experiment:

In order to decide upon the voltage and lengths of wire to use in the

final experiment I tested out 2 different voltages: 3V and 6V. After

performing these rough trials. I decided that 6V would be used in the

proper experiment. I also decided to let the wire to cool between

experiments because I noticed with lower lengths (10cm) it got very

hot, and an increase in temperature results in an increase in