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What is a Magnet?A magnet is an object or a device that gives off an external magnetic field. Basically, it applies a force over a distance on other magnets, electrical currents, beams of charge, circuits, or magnetic materials. Magnetism can even be caused by electrical currents. Scientists use the symbols "M" for the magnetization force and "I" for the current value.While you might think of metal magnets such as the ones you use in class, there are many different types of magnetic materials. Iron (Fe) is an easy material to use. Other elements such as neodymium (Nd) and samarium (Sm) are also used in magnets. Neodymium magnets are some of the strongest on Earth. Different Types of Magnets
There are many different types of magnets. Permanent magnets depend on continuous magnetic flow through the material. There are materials in the world that are called ferromagnetic. Those materials are able to create and hold a specific alignment of their atoms. Since each atom has a magnetic moment (tiny magnetic field), all of the moments add up to create a magnet. Scientists use the word hysteresis to describe the way the atoms stay aligned.
Excited magnets are different because they can be turned on and off. Excited magnets depend on currents of electricity to give them energy. A great example of an excited magnet is an electromagnet. Electric currents are pushed through a plain magnet and the current allows the magnet to do less work for the same results. You might see an electromagnet at work in a junkyard lifting old cars off the ground. 
There are also air-core magnets. Air-core magnets don't have any magnetic material (iron). They are created by current flowing through a wire. That current creates the magnetic field. Do you remember that electric currents produce magnetic fields of their own? You could create an air-core magnet by wrapping miles of wire around a doughnut shape (toroid). When you send current through the wire, a magnetic field is created inside of the doughnut. Scientists use air-core magnets to study fusion reactions.
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Go for site help or list of physics topics at the site map!©copyright 1997-2007 Andrew Rader Studios, All rights reserved. Current Page: Physics4Kids.com | Electricity & Magnetism | Magnets |
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