An electromagnet consists of a solenoid (soil of wire) wrapped around a bar of iron or other ferromagnetic material.     When current flows through the solenoid, it gives it a magnetic field like a bar magnet. The magnetic field of the solenoid magnetizes the ferromagnetic bar by aligning its magnetic domains. The combined magnetic force of the magnetized iron bar and the wire coil makes an electromagnet very strong. In fact, electromagnets are the strongest magnets made. Some of them are strong enough to lift a train. A maglev train contains permanent magnets that are repelled by strong... Show more

An electromagnet consists of a solenoid (soil of wire) wrapped around a bar of iron or other ferromagnetic material.    
When current flows through the solenoid, it gives it a magnetic field like a bar magnet. The magnetic field of the solenoid magnetizes the ferromagnetic bar by aligning its magnetic domains. The combined magnetic force of the magnetized iron bar and the wire coil makes an electromagnet very strong. In fact, electromagnets are the strongest magnets made. Some of them are strong enough to lift a train. A maglev train contains permanent magnets that are repelled by strong electromagnets in the track. The force of repulsion causes the train to levitate above the track.    
An electromagnet is stronger if there are more turns in the coil of wire or more current is flowing through it. A bigger bar or one made of a material that is easier to magnetize also increases an electromagnet's strength. 

Electromagnets are widely used as components of other electrical devices, such as motors, generators, electromechanical solenoids, relays, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment. Electromagnets are also employed in industry for picking up and moving heavy iron objects such as scrap iron and steel.

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