An electromagnet is a type of magnet that gets its magnetic properties from an electric current. Unlike a permanent magnet, which is always magnetic, an electromagnet's magnetic field can be turned on and off and its strength can be controlled. This makes them very useful in many devices.

The creation of an electromagnet is based on a key principle in physics: when an electric current flows through a wire, it creates a magnetic field around that wire. This field is quite weak on its own. To make it much stronger, the wire is coiled into a shape called a solenoid. Coiling the wire causes the magnetic fields from each loop to add up and combine, creating a more powerful magnetic field. To increase the strength even further, an iron core is placed inside the coil. The magnetic field from the coiled wire tells all the tiny, randomly pointing magnetic parts inside the iron [magnetic domains] to line up. When they all line up, they create their own strong magnetic field that adds to the coil's field, making the electromagnet much more powerful.

The main difference between an electromagnet and a permanent magnet is control. An electromagnet can be turned on and off, and its strength can be adjusted by changing the

 current or the number of coils. This ability to control its magnetic force is what makes it useful in things like electric bells and in the cranes used for lifting heavy materials in scrap yards.