I will use constants of voltage and variables of lengths of wire. I will also measure the current and voltage by using a voltmeter and ammeter for extra reliability. I will use crocodile clips to place the wires connected to the voltmeter and ammeter, so I can place them onto the nichrome wire, which is connected to the ruler so I can get the readings. The lengths will have to be carefully measured because I do not want to get the wrong readings. I must take in to account that temperature is very important as it can lose energy in the particles and I will have to measure the resistivity of the circuit without the nichrome wire.
To measure the resistance of each length of wire by using the equation:.
R = V / I.
Where:.
R = resistance.
V = Pd. Across the conductor.
I = current.
This formula will give me a result in Ohms.
From the circuit I have made, I used that knowledge to produce the most efficient circuit for the experiment.
Apparatus:.
Ammeter - 0-5 Amperes.
Voltmeter - 0-5 Volts .
Nichrome wire - different lengths- 50mm-600mm.
Power supply - Ac, 0-5 volts.
Ruler.
Tape to place the wire to the ruler so we can get a fair result.
Health and Safety:.
Electricity is always dangerous so I will stay as far away from water as possible. When the voltage is higher and the resistance is lower there is a chance of the nichrome wire burning. So I will can that into account and will try and get the reading as quick as possible before the wire burning.
Fair Test:.
To make this a fair test I will have to measure the amounts of wire exactly because if it isn't exact I will not get an actual true reading. I will have to keep everything the same during the test only change the lengths of wire.
Circuit:.
.
My circuit is set up like this to make accurate results, the ammeter is in series so all of the amps, have to travel through the ammeter. (It would reduce the number of amps if it were in a parallel circuit because some of the amps have to travel along the other wire).
