What Are Magnetic Poles? How Can You Tell Which Pole is Which?

If you’ve been following our blog you probably know that all magnets have at least one north pole and one south pole. But what are these poles? What do they do? And how can you tell which is which?

Well, the areas of a magnet that have magnetic strength are called “poles”. When you have more than one magnet, like (or same) poles repel, or push, each other. Opposite poles attract, or pull, each other. In other words, the north pole of one magnet will click together with the south pole of another magnet, and two north poles will push each other away. These acts of attraction and repulsion are called “magnetism”, and the magnetic space around a magnet is called the “magnetic field” (click here to learn more about magnetic fields).

repel and attract

Unless they came marked with “N” or “S,” the poles of a magnet look the same. One easy way to tell which pole is north and which is south is to set your magnet near a compass. The needle on the compass that normally points toward the north pole of the Earth will move toward the magnet’s south pole. Wanna know a secret? This works because the needle in a compass is actually a magnet! So the north pole of the compasses’ needle magnet is attracted to the south pole of your magnet.

magnet and compass

Another way to tell which is north and which is south is by dangling your magnet from a string. When you dangle a magnet, it automatically turns itself so that one pole is pointing directly north and the other directly south, which is why we call them the “north” and “south” poles.

You can try this experiment at home!

  1. Put a small piece of masking tape on one end of a bar magnet.
  2. Tie a string around the middle of your magnet.
  3. Dangle the magnet from the string and then from a ruler. Watch as one end orients itself toward the north. This is the magnet’s north pole.
  4. If that is the end with the masking tape, write “N” on the tape. If the other end has the tape, write “S.”

dangling magnet

 

Remember in the intro when we said all magnets have AT LEAST two poles? Well bar magnets have two poles, so their magnetic fields are called dipole which means–you guessed it–two poles! But some magnets have more than two poles. In fact, some have four, or six, or even eight! (These are called “octopoles”– doesn’t that sound like a cool Play Station™ game?) Some celestial objects, including stars and planets, have magnetic fields, and some of them have more than two poles! We call these fields “multipoles.” Earth is a good example of a dipole magnetic field–we have one north pole and one south pole (with a few weaker multipole parts, but let’s not get into that right now). But the magnetic fields around planets like Uranus and Neptune have multiple magnetic fields. Cool, right?

So there you have it: magnetic poles made simple!

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