You have probably held a magnet, and observed how they attract metal as well as other magnets. You may also have noticed that sometimes magnets are not attracted to each other, but instead repeal one another. Why do magnets behave this way? What is going on?

Magnetism is a result of the motion and spin of electrons. This spinning creates a complex reaction that results in a magnet having two poles. Which are a north pole and a south pole. When these poles are line up, opposites attract and likes repel.

Though it is a bit complicated to understand, the way this works is that all objects contain atoms. Which each have electrons spinning around their nucleus in shells, or orbitals. The magnetic field of these electrons is what we call magnetism. You can think of magnets as regions of net electron spin, and thus a region of magnetic field.

The positive charged protons in the nucleus of an atom, attract the negative charged spinning electrons.

Why Are Metals More Susceptible To Magnetism?

As you may know from chemistry class, metals tend to have delocalized electrons – many of their valence electrons are not in any given orbital/shell, but instead float around between different orbitals.

A magnetic field such as those created by magnets cause these free electrons to flow in a certain direction around the metal. If you can make this flow of electrons strong enough, you can use it to move the metal.

Magnetic Fields Are Not Arbitrary And Can Be Calculated

A magnetic field is not just some arbitrary force that you have no way of knowing about – they are lines of force created by the motion of electric charge. Which you can calculate with some relatively simple equations that allow you to determine the strength and direction of the field at any point around a magnet.

So why do magnets sometimes attract, and other times repel?

As mentioned above, like poles repel each other. So if both sides of your magnet are south, they will push each other away. A north pole on the other hand will be attracted to a south pole.

The Earth is A Giant Magnet

Did you know that the planet we live on is actually one very large magnet?  This is why you can use a compass to find north.  The magnet in the compass needle aligns itself with the Earth’s magnetic field, causing it to point north.