Magnetism is the invisible physical force exerted by magnetised material. Magnetism occurs when stable electrons in the atoms of certain materials are forced to align by the influence of an external magnetic field. This force can be generated by either a permanent magnet or an electrical current. The electrons in all common materials are susceptible to magnetic forces. Ferrous materials are strongly magnetic but most other materials are very weakly magnetic. Any magnetised material will generally have a North Pole and a South Pole. The magnetic field flows from the South to the North through the magnetised material. The flow returns to the South pole via the surrounding air space. Two magnets will attract when the opposite poles are facing each other. Two magnets with the same poles facing will repel each other. Most of the everyday incidents of magnetism we experience are caused by Ferromagnetic metals such as iron, cobalt or nickel. Permanent Magnets made from Rare Earth materials are another source of powerful magnetic fields.

Other magnetic events occur due to the effects of electromagnetic fields. Most ferromagnetic materials will remain permanently magnetic under normal conditions. Electromagnets, however, use wire coils charged with an electric current to create a magnetic field. When the conductive wire is wound tightly around a metal core the core becomes a powerful magnet for as long as the current is flowing. Once the current stops, the magnetic field also stops. Unlike permanent magnets, Electromagnets can be turned off and then on again as required.