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Magnet

Lines of force

Magnetic lines of force of a bar magnet shown by iron filings on paper

A magnet is an object that has a magnetic field.

A permanent magnet is made of a ferromagnetic material, which means that the magnetic properties derive from the spin angular momentum of electrons within that material. In a magnet, the magnetic domains in its substance are aligned.

The magnet is a dipole. A magnet can be regarded as having two magnetic poles, one "north" and one "south". The end of a freely suspended magnet that starts to point towards the Earth's geographical North Pole, is by definition the magnetic south pole. Equally, the other end that ends up pointing towards the geographic South Pole, is the magnetic north pole.

However, if you were to cut a magnet in half, you would never get a north piece of magnet and a south piece of magnet. You would instead end up with two smaller magnets.

Magnets can be demagnetized in the following ways:

  • Heat (Heating a magnet until it is red hot will make it lose its magnetic properties.)
  • Contact (Stroking one magnet with another in random fashion will demagnetize the magnet being stroked.)
  • Hammering and/or Jarring (Such activity will loosen the magnet's atoms from their magnetic attraction.)
  • Breaking Electric Current (for electromagnets only)

The Earth's magnetic field has a north and south pole. We can use the magnetic field of the Earth to help navigate by using a magnetic compass. Compasses can also be used to figure out which side of a magnet is the north or south pole of that magnet.

See also:


Magnet is also the name of a commune in the Allier département, in France




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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Magnet".