A magnet is a very special metal. When a magnet goes near a special kind of metal or other magnets, and the poles (sides) touching are opposite, it will pull, or attract the other metal or magnet closer. Also, if the two poles are the same, the two magnets will push away, or repel, from each other. This is called magnetism. Magnets can make some other metals into magnets when they are rubbed together.
Soft magnets (or impermanent magnets) are often used in electromagnets. These enhance (often hundreds or thousands of times) the magnetic field of a wire that carries an electrical current and is wrapped around the magnet. The field of the "soft" magnet increases with the current.
Permanent magnets have ferromagnetism. They occur naturally in some rocks, particularly lodestone, but are now commonly manufactured. A magnet's magnetism decreases when it is heated and increases when it is cooled. It has to be heated at around 1000 degrees Celsius. Like poles (S-pole and S-pole/N-pole and N-pole) will repel each other while unlike poles (N-pole and S-pole) will attract each other.
Magnets are only attracted to special metals. Iron, cobalt and nickel are magnetic. Metals that have iron in them attract magnets well. Steel is one. Metals like brass, copper, zinc and aluminum are not attracted to magnets. Non-magnetic materials such as wood and glass are not attracted to magnets as they do not have magnetic materials in them.
Natural magnets[change | change source]
Natural/permanent magnets are not artificial. They are a kind of rock called lodestone or magnetite.
A compass uses the Earth's magnetic field, and points to the North magnetic pole. A north side of the magnet is attracted to the south side of another magnet. However, the north side of the compass points to the north pole, this can only mean that the "north pole" is really the magnetic south, and the "South magnetic pole" is really the magnetic north.
The first people to discover naturally magnetic rocks were the Chinese. At first, the Chinese used the stones to carry out fortune-telling and magic tricks. Later on they used these "lodestones" to invent the compass.
Related pages[change | change source]
References[change | change source]
|Wikimedia Commons has media related to: Magnet|