What is magnet?
A magnet is a material or the object that produces a magnetic field.Magnetism is a force created by electricity, or more specifically by electrons.

Magnetism


A magnet is anything that carries a static magnetic field around with it. There are lots of kinds of magnets. The ones you find most commonly are permanent magnets made out of some special metals, especially iron, or are mixtures of these metals and other stuff (like rubber or ceramics). Other kinds of magnets need electricity to flow through coiled wires to create a magnetic field. Some magnets are combinations of these -- they have wire wrapped around an iron core. 

How Magnets Work

The magnet itself isn't moving - that part is true. But, there are charges inside it that are moving. Inside the metal, the electrons are orbiting the nucleus of each atom. And when charges move, they produce magnetic fields. In a lot of non-magnetic materials, there are electrons orbiting in both directions, and their magnetic fields cancel out. But in some special magnetic materials, like iron for example, there is not an even number of electrons orbiting both ways, and an overall magnetic field is produced.

But that's not the only kind of motion that's happening. There's something called quantum mechanical spin. Electrons spinning one way will produce a magnetic field, and if the spins of all the electrons don't cancel out, you get a magnetic field.

Atoms in which both of these things don't cancel out act like tiny magnets. And these magnets can combine together to make a material magnetic. They can combine together...but not always. Unfortunately it's a little more complicated than that. Just because the electrons in a material are producing magnetic fields doesn't mean the material will be a magnet. There are a couple of other things that have to be the case for that to happen. For one thing, these tiny magnets could very easily all point in lots of different directions and could cancel each other out.

But In some materials, for the sake of stability, the atoms pull on each other until they line up in nice, straight rows. These are called ferromagnetic materials. So that's how we get a magnet, right? Well, even then there's no guarantee you'll have a magnet. Because you'll often end up with atoms lining up one way in one part, and a different way in a different part, creating lots of what we call domains. If those domains line up in random directions, they will cancel out.

But if you put your ferromagnetic material, like iron, in a bigger, external magnetic field, you can force all of those domains into alignment and produce what we usually just call a magnet. Over a long period of time, the earth's magnetic field can align the domains in a material like iron and produce a fairly weak magnet. This is why we can find rocks on the ground with magnetic properties. But generally, we create proper magnets by putting iron inside our own magnetic fields created using electromagnets. It's kind of like charging the iron - forcing the domains to align. Once you've lined up the domains, the external magnetic field is no longer needed, and they will stay aligned for a long time.

What are magnets used for?

Magnets are used in computer data storage, compasses, doorbells and alarm systems, microphones and speakers, motors, electrical generators and electrical transformers. They are also used to levitate objects, including trains that operate via magnetic propulsion. Naturally occurring magnetism protects the Earth from cosmic radiation.

Magnets are also used in a variety of medical and veterinary applications. Magnetic resonance imaging uses magnetic fields to view internal organs, and electromagnetic fields promote the healing of broken bones. A similar treatment prevents bone loss in astronauts outside of Earth's gravity.

In veterinary medicine, magnets are used to treat hardware disease in cows. The condition occurs when cows swallow metal objects, which can puncture their organs. Cows can be fed magnets as a preventative; any metal objects swallowed will be drawn to the magnet instead of puncturing the cow's stomach. Magnets can also be used to ensure cows' feed is clear of metal objects before ingestion. Unlike in cows, swallowing magnets is a medical emergency for humans; they can perforate the intestines.

Other medical uses for magnets, such as applying magnets topically to treat pain, are not proven by scientific studies. Magnetized drinking water is similarly unproven; scientific studies show no evidence that it has any health benefits.