Pole Naming Conventions

The north pole of the magnet is the pole which, when the magnet is freely suspended, points towards the Earth's north magnetic pole in northern Canada. Since opposite poles (north and south) attract whereas like poles (north and north, or south and south) repel, the Earth's present geographic north is thus actually its magnetic south. Confounding the situation further, the Earth's magnetic field has reversed itself many times in the distant past.

As a practical matter, in order to tell which pole of a magnet is north and which is south, it is not necessary to use the Earth's magnetic field at all. For example, one calibration method would be to compare it to an electromagnet, whose poles can be identified by the right-hand rule.

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