Investigating the factors which affect the resistance of a wire.

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Investigating the factors which affect

the resistance of a wire

Aim:

To investigate how the length of a wire affects the current and resistance of a wire. There are many things that affect the resistance of a wire but I have only got the chance to do one of these. The one I will choose will depend on it being the most effective and on its ease to do.

Research:

Resistance is when travelling electrons in a wire collide with the atoms within the wire. The collisions of the electrons makes them move slower through the wire, which is what causes the resistance. So resistance is basically how hard it is for an electron to move through a wire. There are many factors, which affect the resistance of a wire, and they are described in the next section.

Some metals have less resistance than others. Wires are always made out of copper because copper has a low resistance and therefore it is a good conductor. The length and width of a wire also has an effect. In this investigation I will investigate how the length of a wire will affect the resistance in the circuit.

Key Variables:

Some of the variables that will be relevant to this investigation are:

- Length – the longer the wire, the longer it will take for electrons to reach the end of the wire. This is because there will be more collisions between the electrons. So therefore, the length of the wire should be directly proportional to the resistance.

- Thickness – This will cause the resistance to decrease because of the increase in space for the electrons in the wire to move through. The more space there is, the easier it is for the electrons to flow through the wire, and causing fewer collisions.

- Temperature – If the wire starts to heat up, the atoms will move around more because of the increase in energy. This will cause there to be more collisions between the electrons and atoms and therefore increase the resistance.

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- Material - Thirdly, the material used would be a factor. If the material being used contains atoms with a large number of electrons on the outer shells, then this means there are more electrons available. That means that a material with a large number of electrons in the outer shell should have less resistance. If the atoms are more closely packed, it will be harder for the electrons to flow through the material and this will cause the resistance to be increased.

Prediction and Hypothesis:

I think as you increase the length of the Constatan wire, there is also ...

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