Planning
Resistance of a Wire Investigation
Introduction
Resistance is measured in Ohms. This is calculated by finding both the current and the potential difference over a test substance. Then by using Ohms Law, you can find the resistance of any material over any distance.
Ohms law is; Resistance (R) = Potential Difference (V)
Current (A)
Variables
- Length of wire
- Thickness/Diameter of wire
- Material wire is made from
- Surface area of wire
- Number of coils of wire
- Density of wire
- Temperature of wire
- Atmospheric conditions
- Amount of current flowing through wire
- Potential Difference flowing through wire
- Material wire is wrapped around
I have chosen to use the length of wire as my variable. I have chosen this particular one because it is easy to carry out easily without too much chance of error. It is difficult to measure the surface area, density and the thickness of the wire accurately so they were eliminated. Altering the amount of current alters the potential difference and vice-versa. Also, if too much current or potential difference is used, it also alters the temperature of the wire because it causes the wire to heat up. The material the wire is wrapped around would make little difference to the resistance of the wire so that variable was also eliminated. After assessing the situation, the best variable to use is the length of wire as it can be altered easily using a jockey and the results are easy to obtain accurately. The range I have chosen for this experiment is between 0 and 100 centimetres. This is because it can be easily calculated accurately using a metre rule.
