Osmosis
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Resistance of a wire
Aim: to investigate how the electrical resistance of a wire changes in relationship to its length.
Variables
Length of wire.
Width of wire.
Voltage of power pack.
Key Variables
Length of wire.
Fair test
in this experiment we are only changing one factor - the length of the wire, the factors that we are going to keep the same are as follows:
We must keep the surrounding room temperature the same or the particles in the wire will move faster (if the temperature is increased) and this will therefore have an effect on the resistance.
The cross sectional area of the wire must be kept constant throughout as well. This is shown in equation (2) where the cross sectional area is a factor that effects the resistance.
The material of the wire must also be kept the same as different materials have different conductivity. The last two factors will be kept the same by using the same wire all of the way through the experiment...