Is there like a “standard” that it’s compared to or???
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If you make a compass out of the magnet it is the side that will point to the North. Magnetic north refers to the actual North Pole of the planet Earth and how magnets react to it.
A magnetic compass needle will point with its south pole to Earth’s north magnetic pole. This way you can determine which of the compass magnet ends is north. If you then bring a magnet close to the compass, the needle’s north will turn towards it (if you bring the magnet’s south pole closer) or away from it (if you bring the north pole closer).
It might seem a bit misleading because the Earth’s north magnetic pole is actually the south pole if you think of the Earth as a giant magnet. It’s because the magnets’ north was defined as the side of a magnetic needle that points to (is attracted to) the north direction in a compass.
The reference is the Earth’s magnetic field, that’s why we call the magnet’s ends north and south poles to begin with.
“North” and “South” are arbitrary, just like “positive” or “negative” charges in electricity. We could have named it “john” instead of “north”, and “suzy” instead of “south”. Or “south” instead of “north”, and “north” instead of “south”.
Those are just two opposite polarities. Opposite polarities attract.
If you get two magnets and put them together, and they attract, you know that the two ends that attracted are of the opposite polarities, so you name one “north”, and the other one “south”.
Now if you’ve got a third magnet, put one end of it near the one you named “north” and it attracts, you now know that this one is “south”.
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?
Yes, it could be compared to a “standard”
That “standard” though would Just be, like someone else commented, any magnet with a known alignment.
We can use the earths magnetic field, since ww know its direction. Thats probably what they do in factories where they label magnets.
We could also get a magnet with a known alignment with an electromagnet; we know the direction of the current through our electromagnet, so we know the direction of north and south in our electromagnet (current creates the magnetic field, and so Current direction determines the field direction)
You hang it up and see which end points north. That’s the north end. If you can’t practically do that you compare it to a magnet with a known parity.
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