In order to produce an electromagnet you need to have a soft iron core and wire. You need to coil the wire around the iron core and pass a current through the wire to get a magnet.
You can vary the strength of this magnet in a number of ways:
- Change the number of turns on the coil
- Alter the size of the current
- Alter the size of the iron core
- Change the shape of the iron core
- Change the material of the core
- Change the ways in which the coils are wrapped around the core
- Change the nearby magnetic fields
To find out how the electromagnet is affected when the variables above are changed I will take one of the variables and record how the magnet is affected by it’s change. I will not change any of the other variables to ensure I’m carrying out a fair test.
I have decided to vary the current passed through the electromagnet. I shall do this by using a variable resistor in the circuit and by altering the voltage from the power supply. I will vary the current over a range of 5 Amps (0 – 5A). I will test the strength of the magnetic field by placing an iron nail at the bottom of the iron core, it will become magnetised and depending on the strength of the field will stick there. I will then add weights to the nail and record how much mass it will hold before it drops off the magnet.