How Do Magnets Work?

How do magnets work? A magnet produces a magnetic field which attracts metals such as iron, cobalt, and nickel. In this magnetic field, the lines of force exit through the north pole and enter through the south pole. A magnet can have more than one north or south pole, but they always occur in pairs, so if it had two north poles, it would also have two south poles.

The strongest natural magnet is lodestone. It is a type of magnetite, and is not very strong, as it can only attract small objects like paper clips. By the 1100s, lodestones were used to make compasses by rubbing the lodestone along the needle. A scientist named William Gilbert explained that the needle pointed north because the Earth was a big magnetic, with north and south poles.  

The lines of force leave the magnet at the north pole and enter at the south pole, so that explains why opposite poles attract. Poles that are alike would have nowhere for the lines of force to go, so they repel one another because they are traveling at opposite directions. This partially explains the answer to, “How do magnets work?”

To make a magnet, you have to encourage the alignment of the domains. Domains are like microscopic magnets, each with a north and south pole. The more domains that line up, the stronger the magnet becomes. The three ways to do this are: to place the object in a strong magnetic field, hold it in a north-south direction and strike it repeatedly, and pass an electric current through it. There is a theory that lodestone is created when magnetite was struck by lightning, causing it to become magnetic. Another theory states that magnetite was formed at the beginning of Earth’s formation, when iron oxide was molten.  

Today, magnets are made by putting the object into a magnetic field. If you want to de-magnetize a magnet, you put it in a field that is aligned in the opposite direction or heat it above its Curie point. That is the temperature where it loses magnetism.    

How Do Magnets Work?

Magnets work by producing magnetic fields. There are three different kinds of magnets:

• Permanent magnets (hard magnets) create a field constantly.
• Temporary magnets, or soft magnets, will have a field when in the presence of a field, but lose their field soon after leaving the other field.
• There are wire coils in electromagnets that produce a magnetic field when electricity passes through them. 

Magnets work because of the movement of electrons. Electrons can act like particles or waves, and they have a charge and mass. So when they move, they produce a tiny magnetic field. For certain metals it is easier to have their atoms aligned in a north-south direction. That is why some materials don’t react with magnets at all, as it is too hard for their atoms to align. So the answer to, “How do magnets work?” can be explained on the atomic level, but still involves fields and lines of force.  

Uses of Magnets

Magnets have many uses. For example, a computer uses magnets to store data.  Magnets are important parts of televisions, compasses, speedometers, generators, transformers, electric motors, and burglar alarms. Trains use magnetic propulsion to travel fast and the Earth uses its magnetic field to protect it from the solar wind.  

Medical uses include MRIs (Magnetic Resonance Imaging) and electromagnetic fields that can help bones heal as well as helping to prevent bone and muscle loss in zero gravity environments. Also, magnet therapy involves placing magnets on parts of the body to alleviate pain. It is said that this works because more blood is attracted to the area (the iron in the blood), which speeds healing, and the magnets affect nearby cells. 

Another interesting use has to do with cattle. They sometimes ingest metal objects, and this can cause internal problems. Magnets can locate and remove metal from their feed, and specially designed magnets can be swallowed that will keep the metal from harming the cow’s stomach. By the way, if a human swallows magnets, it will sometimes require surgery to remove.