Remember the time when you discovered how two magnets could snap and stick together? Seemed like magic didn't it? Playing with magnets is probably a child's first exposure to magnetism. A material that generates a magnetic field is known as a magnet, and the phenomenon is known as magnetism. Magnetism
is defined as a phenomenon in which a force is produced by charged particles (electrons) of a magnet. In simpler terms, a magnetic substance, for example iron, is attracted by a magnet with the force of magnetism. The force generated can be either attractive or repulsive, depending on the alignment of the charged particles.
How Does Magnetism Occur?
Every charged particle produces a magnetic field when it moves. Hence, an electron that spins around the nucleus also generates a magnetic field around it. The difference between a magnet and other substance is that in the former, all the electrons move in the same direction, thus producing a static magnetic field around the magnet. In case of other substances, the electrons spin randomly, hence dispersing the magnetic field in different directions. In such a condition, there is no profound magnetic effect.
The magnetic effect of a magnet is strongest at the ends (poles); each magnet, irrespective of its size, has two poles―the north pole and the south pole. Conventionally, it is studied that the magnetic field leaves the north pole and enters the south pole. A magnet is called a dipole as it possesses two ends that act differently; opposite poles attract, whereas like poles repel each other. Likewise, an electromagnet is a magnet that requires electricity to generate a magnetic field. Magnets, due to their specific properties, are used in electrical appliances, compasses, industrial magnets, printing magnets, construction works, as magnetic strips in cards, magnetic bracelets, magnetic therapy, and several other domains.
Types of Magnetism
Based on the configuration of electrons in the material, magnetic behavior is classified into several types. One of the most important magnetic behavior is ferromagnetism. Ferromagnetism is the property of a material that remains magnetic even after the removal of a magnet. Ferromagnetic mechanism is used for creating permanent magnets, for example, magnets used in refrigerators. In the process of making a magnet, a ferromagnetic material is heated first and cooled gradually under a strong magnetic field. As the material cools down, the electrons are forced to align in a particular direction, resulting in a permanent magnet.
Diamagnetism is a type of magnetism exhibited by materials. A diamagnetic material produces an opposite magnetic field when an external magnetic field is applied on the material. Example of diamagnetic materials include copper, gold, and mercury.
Paramagnetism is more or less similar to diamagnetism. A paramagnetic material is attracted to a magnetic field and generates its own magnetic field in the presence of an external magnetic field. Examples of materials that exhibit paramagnetism are uranium, iron oxide, and platinum. In addition, there are other magnetic behavior such as spin glass (irregular magnetic fields) and superparamagnetism (contains minute ferromagnetic clusters).
Earth ― A Magnet
Did you know that Earth is a giant magnet? Yes, the planet Earth also exhibits magnetism, which is referred to as Earth's magnetic field or external magnetic field. The magnetic attraction is largest at the North and South poles. When a magnet is suspended in the Northern Hemisphere, the south pole of the magnet points towards the south direction of the Earth. Similarly, when the same magnet is suspended in the Southern Hemisphere, the south pole still points to the south direction. This phenomenon of magnetism is used for the construction of a magnetic compass.
Magnetism is a mysterious phenomenon that goes on in the everyday life, and indeed a vast, but interesting topic to be studied on.