What is magnetism?
Magnetism is a phenomenon involving magnetic fields and the effects on other materials exposed to a magnetic field. A magnetic field is a region of forces that exists around a magnet. The field can be drawn as a series of curved lines, called “lines of force”, joining the north and south poles of the magnet. The Earth itself behaves like a giant magnet. Its magnetic field, caused by electric currents inside the liquid part of its core, stretches thousands of miles into space. Fields from both permanent magnets and electromagnets have the same effect on surrounding objects and are both referred to as “electromagnetic” fields. The force generated by an electromagnetic field together with gravity, the weak atomic force, and the strong atomic force, constitute the four fundamental forces of nature.
In physics, magnetism is one of the phenomena by which materials exert an attractive or repulsive force on other materials. Some well known materials that exhibit easily detectable magnetic properties are iron, some steels, and the mineral lodestone; however, all materials are influenced to one degree or another by the presence of a magnetic field, although in most cases the influence is too small to detect without special equipment.
