The first compasses were made from natural magnetic stones, made from the mineral magnetite, Fe3O4. Known as leading stones, or lodestones, it’s a matter of debate how these stones originally became magnetized. A leading theory is that the strong magnetic fields created by lighting are responsible—a theory supported by the fact that most lodestones are found only near the earth’s surface.
The earth’s magnetic field is generated by the motion of liquid iron in the planet’s core. This “geodynamo” occasionally reverses its polarity, with the magnetic north and south poles swapping places. The switch isn’t instantaneous, but takes place over a few thousand years, with the time between reversals varying from tens of thousands to tens of millions of years.
Different cultures throughout history have noticed how magnets align. Just as you did in this exploration, each chose a particular direction—north or south—to be significant. The Chinese chose the south-pointing end, while the Europeans chose the north-pointing end. In choosing to mark the face of your donut magnet, did you make the same choice as the Chinese or the Europeans?
The ancient Chinese belief in geomancy (interpreting mystical signs according to their physical orientation) gave extra value to the southerly direction, while European cultures, having adopted the North Star as a navigational tool, saw the magnetic needle of a compass as a way to locate north when the North Star wasn’t visible.
Many scientific definitions and benchmarks are determined by “standards committees,” groups that meet to define such things as the location of the north pole of a planet. By deciding to call attention to one of the two possible directions for the hanging magnets, you and your partner have become a standards committee.