Magnetism. The most familiar form of the physical phenomenon called magnetism is the ability of certain objects to attract iron. Such objects are called magnets. Magnetism is also associated with electric currents. Magnets are widely used. All electric motors (and the generators that provide power for the motors) contain magnets, as do telephones, tape recorders, and loudspeakers. The magnetic compass is a device used for finding direction. The earth itself is a huge magnet.
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For centuries, curious observers have probed the heavens with the aid of telescopes. Today, both amateur and professional scopes magnify images in a variety of ways.