Educating Rita

Physics coursework

I am going to investigate how the length of wire is going to affect the resistance of a wire.

I am going to measure the current each time I change the length of wire.

The current is a flow of negative electrons around the circuit. Electric current will only flow if there are charges which can move freely. This is why electric current flows so well in all metals. Electrons always move from a place where there are too many electrons to a place lacking electrons. The current in a series circuit is the same at all points. The current in a parallel circuit divides between the two different paths. Current always flows from -ve to +ve.

I am going to use the following equipment:

*A circuit board

*5 links

*6 wires

*An ammeter

*2 crocodile clips

*Constantan wire (various lengths)

*A power pack at 4V.

I have decided to use the power pack instead of the battery pack as this gives a constant voltage which makes the experiment fair; if I did use the battery pack it probably wouldn't give as much voltage as possible as the batteries have been used before.

Method:

I will set up the equipment as shown in the diagram below.

I am going to start with a 65cm length of wire which will be decreased by 10cm each time. This will give me a range of 5 different lengths going from 65cm, 55cm, 45cm, 35cm, to 25cm.Before starting the experiment I need to make sure that everything is correctly set up and everything is safe. Whilst doing the experiment I have to remember safety at all times, I will have to have dry hands and I will have to make sure that the wire does not get to hot so that it will melt.

I have worked out from