Nickel, iron and cobalt are magnetic metals. Most other metals, including gold, copper, silver and magnesium, are generally not magnetic, although some of these metals might become slightly magnetic if placed in a magnetic field.
Magnets are created by heating a suitable metal enough to exceed the material’s Curie temperature. This aligns the small magnetic fields produced by the material, enabling them to work together. Over time, these individual magnetic fields, called domains, fall out of alignment, causing a magnet to demagnetize. Scientists can also make electromagnets by passing electric currents through coils of wire surrounding a metal object, such as a nail. This principle is used in most engines and turbines and during the production of electricity. Not all magnets are man-made, and some are naturally occurring. For example, the mineral lodestone is magnetic. One of the first magnetic substances discovered, lodestone was used to create early compasses.
The Earth’s magnetic field is produced by the movements of the inner core. Scientists believe that the core is composed primarily of iron and nickel, which are both magnetic. This magnetic field is what causes the needle of a compass to point north. Additionally, the planet’s magnetic field deflects the charged particles that stream from the Sun.