Electromagnetic wire is coiled around a rod. When a wire carrying electric current is coiled into a number of loops, the magnetic field gets stronger. Since this magnetism is caused by the electricity, it is called electromagnetism and the coil is called an electromagnet.

To make the magnetic field even stronger, the electromagnetic wire is usually coiled around a rod made of a conductor material. This rod is called the core. Cores are often made with a magnetic material, such as iron, nickel or cobalt.

Generally there are two ways to make an electromagnet stronger: by adding more coils around the core, and by increasing the current flowing through the wire.