Electromagnets

when heating and then cooling an unmagnetized piece of iron in a magnetic field, for example, or by tapping the iron with a strong magnet.

In each magnet situation, the magnet has individual atoms aligned. The individual atoms act like a tiny bar magnet with the positive and negative aspects of each atom attracting each other. Heating and cooling or “tapping” will align the atoms completely in a permanent way. Each atom acts like its own magnet within a larger magnet. Increased heat allows movement of the atoms so that they can more easily align.

There is a specific temperature for each type of substance that will not magnetize the metal, called the Curie temperature that, for iron, is 1043 degrees Kelvin. This is when thermal agitation is so great that it doesn’t carry a magnetic charge consistently.

ELECTROMAGNETS

Electrical currents can cause magnetic effects so that a compass needle can be deflected by a current-carrying wire. Electromagnetism is the use of an electric current to make magnets. This is a temporary phenomenon that makes electromagnets but they are extremely useful. These types of magnets are used in magnetic resonance imaging in medical circles and are used to lift cars in wrecking yards. When you take iron filings, for example, they create a pattern around a magnet and around an electrical current that looks the same in both situations. Electric current is, in fact, the source of all magnetism.

Strong magnetic effects can be created with a ferromagnet and an electromagnet. These two enhance one another. Magnetic information can be stored on videotapes and computer hard drives are applications of magnetism in common use. A CD player will have a rotating magnetic disk as well as a read/write disc. These will incorporate digital theories by having magnetic regions and nonmagnetic regions.