The Online Library of Knowledge

Electricity and magnetism

Magnetism

A scrapyard crane using an electromagnetA scrapyard crane using an electromagnet Magnetism is a force that attracts some objects to other objects. Electricity can produce magnetism and magnetism can produce electricity. We cannot see the force of magnetism. But it is all around us since the Earth itself produces a magnetic field. A magnetic force affects mainly objects and substances that contain the metal iron; it attracts them. The force is present as a magnetic field around a magnet, which is itself usually made of iron. Magnets of different sizes and shapes have hundreds of uses, from holding notes on a refrigerator to being vital parts in electrical generators, motors and loudspeakers.


Iron filings reveal the magnetic field around a magnetIron filings reveal the magnetic field around a magnet

Magnetic poles

A magnet does not always attract another magnet. The magnetic force field is strongest at two areas called its poles. These are different from each other and known as north and south poles. The north pole of one magnet attracts the south pole of another magnet. But it pushes away or repels the other magnet’s north pole. The general rule is that unlike poles attract, like poles repel.
 

The Earth has a magnetic field and two magnetic polesThe Earth has a magnetic field and two magnetic poles

Earth's magnetic field

Iron is not the only metal that can be easily magnetized when placed in a magnetic field. Others include nickel and cobalt.

© 2019 Q-files Ltd. All rights reserved. Switch to Mobile