A coil with an iron core is called an electromagnet.
The iron core increases the coil’s magnetic field strength.
A simple electromagnet is made by coiling wire around an iron nail.
Iron is easily magnetised and demagnetised.
Steel is more difficult to magnetise and is not easily demagnetised.
An iron core makes a temporary electromagnet.
It loses its magnetism as soon as the switch is opened and the current is switched off.
A steel core makes a more permanent magnet.
It does not lose its magnetism quickly when the current is switched off.
Electromagnets with iron cores are used: