Some variables that will be relevant to this investigation are:

Of these the variables will be input and output voltages in experiment one, and length and resistance in experiment two. The other variables (temperature, material and voltage) will have to be kept constant in both experiments to make sure that only length, thickness and resistance are investigated. In experiment 1 the same bit of wire and the same thickness need to be kept constant. In experiment 2, the length will need to be kept constant to make sure only the variables indicated are investigated to ensure a fair test.

Metals conduct electricity because the atoms in them do not hold on to their electrons very well, and so creating free electrons, carrying a negative charge to jump along the line of atoms in a wire. Resistance is caused when these electrons flowing towards the positive terminal have to ¥jumps' atoms. So if we double the length of a wire, the number of atoms in the wire doubles, so the number of jumps double, so

Experiment One - First a length of wire over a metre long is sellotaped to a metre rule. The positive crocodile clip is attached at 0cm. And the negative is moved up and down the wire, stopping at 20, 40, 60, 80 and 100cm. Each time reading the ammeter and voltmeter to work out resistance R = V/I. This is using 30 SWG wire. Other variables, voltage, thickness, and temperature will be kept constant, although the temperature will rise once current is passing through it, which will cause the atoms in the wire to vibrate, and so obstruct the flow of electrons, so the resistance will increase, creating an error. In both experiments constantan wire is used because it does not heat up as much as copper, so the resistance is not effected as much.

Some common words found in the essay are:
Evaluation Experiment, , Method Experiment, Physics' Abbott, directly proportional, ammeters voltmeters, kept constant, resistance wire, current flow energy, current flow, spread resistance, resistance halve, flow energy, wire doubles, using formula, temperature voltage current, accurate average investigate, factors temperature voltage, investigate factors temperature,
Approximate Word count = 1591
Approximate Pages = 6 (250 words per page double spaced)