How Do Magnets Work

Do you remember the joy you felt at the dumbstruck face of cousin Billy, when you moved your car over the table top without touching it? Little did young Billy know that you were using a magnet from under the table to move the car!
Magnet is believed to have been accidentally discovered by a shepherd named Magnes in northern Greece. While herding his sheep, the nails in his shoes and the end of his staff got stuck to a large piece of rock. He dug the earth below to find the Lodestone, which had natural magnetic properties.

How do magnets work
Magnets exhibit their magnetic properties through magnetic force which acts within the magnet's magnetic field. The magnetic force is the result of moving electrons in a magnet. A magnet has a magnetic pole at each end. One end is the North Pole and the other is the South Pole. If the north pole of a magnet is placed facing the south pole of another magnet, the magnets will be attracted to each other. However, bringing together two north poles or two south poles causes the magnets to repel. When a magnet is freely suspended within the magnetic field of another magnet, its north pole will move under the influence of the magnetic field. The line along which the north pole moved, is the magnetic line of force. These lines run from north pole to south pole, and are responsible for attracting and repelling objects.

Earth's Magnetic Field
The Earth also has a magnetic field. This is attributed to an imaginary magnet inside the earth. The north pole of this magnet is towards the South Pole of the earth while its south pole is towards the North Pole of the Earth. If a magnet that is free to move is suspended, it will always align in the north-south direction under the influence of the Earth's magnetic field. This is how a compass needle (which is a magnet) works to point the geographic north and south of the Earth.

Where do Magnets come from?
While some materials like lodestone and magnetite are naturally occurring, some are made by man in a laboratory. Man made magnets are made of iron, nickel or cobalt. An object can be magnetized by rubbing a permanent magnet repeatedly, in one direction, over it. Another way is by passing electricity through a coil of wire around the object. Certain objects can be magnetized by chemical reactions as well.

Naturally occurring magnets like lodestone, are permanent magnets. They retain their magnetic properties over a long period of time. Some of the permanent magnets are also manufactured by humans. Temporary magnets are those that act like permanent magnets under the effect of a strong magnetic field. They lose their magnetic properties once the magnetic field ceases to exist. Temporary magnets are used in electric motors and telephones.

What happens when a Substance is Magnetized?
A magnetic material is supposed to be made of a number of small magnets. When an object is magnetized all these small magnets get aligned so that the north poles of all these smaller magnets point towards one another. This end forms the north pole of the magnet. The other end, towards which south poles of all the smaller magnets point, form the south pole of the magnet. A magnet gets demagnetized when the alignment of these smaller magnets is broken. A magnet can be demagnetized by heating it, hammering or striking it hard or by stroking it with another magnet in a random fashion.

Magnets are used in televisions, computer discs, doorbells and refrigerators. It is also used in magnet therapy. In industries, they are used in conveyors, separators and grates to remove ferrous impurities from large scale industrial flow. Right since their discovery centuries ago, magnets have made found application in a number of products that have become a necessity of the present day lifestyle.