A magnet is a material that produces a magnetic field. The earth as a whole is the largest magnet. The earth has both a north and south pole as most magnets and it produces a force (magnetic force) pulling on ferromagnetic materials such as iron.
Smaller magnets like one can hold in your hand produce a magnetic field which is invisible to the eye but before the end of this article we will demonstrate a method that you can use to see the field. A magnet like the earth has both a north and a south pole. If you put the north pole of 1 magnet to the south pole of another the magnets will attract each other. If however you place them north pole to north pole or south pole to south pole they will repel each other. This is what those trains (Mag Lev) or magnetic levitation trains that travel well over 200 MPH. depend on as the magnets used on these trains are powerful to lift the train from the track. This allows the train to travel above the track without any or very little friction.
There are 2 other divisions in the world of magnets. These are the electromagnets and the permanent magnets.
Electro magnets are produced by a coil of wire wrapped around a metal object and then applying an electric current. These are different than a permanent magnet in that when the current is removed it cuts off the magnetic field. A great example of an electromagnet is the one in those car junk yards that actually pick up the cars. These can be very strong magnets and that feature cutting off the current comes in handy once the car is picked up and moved the current is cut off and the car is let go.
Permanent magnets differ in that they are composed of a material that produces its own electronic field.
The material may be a loadstone which is a naturally occurring magnetic material or it may be an alloy like the popular and very strong neodymium magnets. So what are these neodymium magnets ? Well, they may be called neodymium magnets but they are really an alloy consisting of Iron, boron & neodymium and then magnetized.
Under normal conditions these magnets do not lose their magnetism. However, under extremes of temperature they may lose it. Neodymium for instance has a top working condition of 175 F. Above 175 F. there is a rapid loss of power. This loss of power at a certain temperature point is called the curie temperature. The ability of a magnet material to resist the loss of power before it secumes is called coercivity.
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