Only some magnets have magnetic fields and poles.

What are magnets that always have a magnetic field called?

You can control the strength of a permanent magnet.

Permanent magnets can be turned on and off.

What device uses a permanent magnet to show direction?

How would the magnetic field of an electromagnet be described?

Electromagnets are what type of magnet?

The strength of an electromagnet can be controlled.

Electromagnets can be turned on and off.

What types of devices use electromagnets?