How Do Magnets Work?

The fundamental principle behind magnetism is the magnetic field, which arises from the motion of electric charges. This field exerts forces on other magnetic objects and moving charges, causing attraction or repulsion. For instance, Earth’s magnetic field causes compass needles to line up in direction of the field. Magnetic fields may be represented by continuous lines of force or magnetic flux that emerge from north-seeking magnetic poles and enter south-seeking magnetic poles. A magnet is any material that can produce a magnetic field outside of itself.

Different materials exhibit varying degrees of magnetism. Most materials are diamagnetic, which means they are weakly repelled by both poles of a magnet. Paramagnetic materials such as chromium are weakly attracted to magnets. Ferromagnetic materials, such as iron, nickel, and cobalt, are strongly attracted to magnets and are the only elements capable of being permanently magnetized.

The process of magnetization involves aligning magnetic domains, small volumes within a ferromagnetic material. Pieces of iron, nickel, and cobalt appear unmagnetized because these domains are oriented in different directions. When a magnetizing field is applied, domains reorient in the direction of the field. This alignment can be temporary or permanent, depending on the strength of the magnetizing field. Permanent magnets retain their magnetization due to the alignment of domains, while temporary magnets lose their magnetization when the external field is removed.