The Length of a Wire Affects Its Resistance

The Length of a Wire Affects Its Resistance

Scientific Enquiry:

I know that metals are good conductors of electricity. Metals are good

conductors because their electrons are easily released allowing

electricity to flow.

The electrons can carry current because they split up from the

positive ions, so they are free to move and to carry current.

Factors that affect resistance:

1. Length – the longer the wire the more atoms there are for the

current to push through.

2. Width – there is a greater collection of atoms.

3. Material – Different materials have different atom structures so

resistance varies.

4. Temperature – the hotter it is the harder it is for current to

get through.

5. Voltage – the higher the voltage the more resistance there is.

Planning:

Aim:

The aim of this investigation is to find out how the length of a wire

affects its resistance.

Prediction:

I predict that, as the length of the wire increases so will the

resistance. I think this will happen because as the wire gets longer

the current has more atoms to get through. If the length of wire is

twice as long, the resistance will double e.g.

Length of wire: 10cm Resistance: 4Ω

Length of wire: 20cm Resistance: 8Ω

Apparatus:

Power pack – this provides energy for the circuit

3 wires – are used to connect power pack to resistance board

Resistance board – nichrome wire is tied to it and the board is used

to work out the length of wire

Nichrome wire (0.2mm) – alloy of nickel and chromium. Acts as a

resistor

Ammeter – measures current

Crocodile clips – connect wire to nichrome wire at different length

Preliminary work:

Before the main experiment I did some preliminary work to see if I

could improve on our first method. I concluded that we are not going