How do we know which end of a magnet is North?

Question

Is there like a “standard” that it’s compared to or???

In: 21

Answer 1

You can only tell whether north or south by seeing how it reacts to a field where the north and south are already known, or which way a current flows under the influence of that magnet when moved. Those are the only measurable ways to define polarity.

The earth’s existing field is the standard. We call any pole that orients toward the north of the earth as the “north magnetic pole” of that magnet (north because it points north). Given that opposites attract, this means that the north magnetic pole of the earth is actually a south magnetic pole as we would define it. Ironic, eh?