What happens when a magnet breaks?

A magnet consists of a north and south pole. Something really interesting happens when a magnet breaks in the middle.

What happens to the poles when a magnet breaks?

When you break a magnet, you would almost think that you either destroyed it or could get 2 different magnets out of it.

Here we have a drawing of an axially magnetized magnet (i.e. a magnet with the magnetism on the faces - not on the pages). And the colors show how the poles are positioned.

Purely logically, one would think that, as in the drawing above, a magnet could be divided into a north magnet and a south magnet.

But instead it happens that you get 2 new magnets. So 2 new magnets, each with its own north and south pole.

Why does a broken magnet become 2 new magnets?

To understand what is happening, one must know that the electrons in magnets always face the same direction (a kind of "magnetic domains"). And that's why it happens when you break a magnet that the electrons form 2 new magnets, where the broken parts of the magnet get a "new pole" in relation to the original magnet.

When a magnet breaks , it will therefore still have oppositely directed poles at the ends. That is north on one surface, and south on the other. And it will still be magnetic. But it will become weaker as the size changes and thereby also the magnetic field; i.e. a lower carrying capacity than if the magnet were whole.

Even if you break a small piece of the magnet, you will still be left with a new small magnet, which has a north pole and a south pole.

Make a magnet for two new magnets

The experiment of breaking a magnet in 2 to get 2 new magnets is most fun when breaking a magnet with axial magnetism - i.e. as we know magnets with the poles on the faces instead of the sides.

A broken axially magnetized magnet gives the division with new poles.

If, on the other hand, you break one with diametral magnetisme then the poles will still face the same direction and you change not on anything about the magnet, other than that you have 2 smaller magnets but with exactly the same poles as before.

An exception to the rule

This process of getting 2 new magnets only happens , if the crack is not too hard for the magnet. The magnetism will be affected if you e.g. saws, hammers or drills into the magnet: then the magnetic domains will no longer reinforce each other's magnetic field, and you may end up with a completely destroyed magnet instead, which is at best only slightly demagnetized.