What is magnetism and how is it useful? In order to give a clear explanation, some background information must be known. The word magnetism comes from the ancient Greek name for certain naturally occurring iron oxide stones called loadstones. These stones were thought to be first discovered in an ancient country in the Asia Minor, called Magnesia. There is a story that a Cretan shepherd by the name of Magnés, whilst tending sheep on the slopes of Mount Ida, found that his iron tipped crook and the nails of his boots were attracted to the ground. To find the source of the attraction he dug up the ground to find stones that we now refer to as lodestones (also spelled loadstone; lode means to lead or to attract), which contain magnetite, a natural magnetic material Fe3O4. Also Thales of Miletus (630 - 550 B.C.) is credited with...