The earliest compass was called Sinan. In fact, the compass did not point directly south, because there was a certain deviation between the geomagnetic poles and the geographic poles. So what is the compass principle? In addition to absorbing iron, magnets have the characteristics of the pole, that is, it will fix the two large magnetic fields of the north and south poles that point to the earth. The compass is made of this principle.
The compass is closely related to the earth's magnetic field. We live on the earth with the South Pole and the Arctic, and the earth is also a large magnet, with two magnetic poles, one called the geomagnetic north pole, also called the N pole, the other called the geomagnetic south pole, also called the S pole, the geomagnetic Arctic near the earth's south pole, and the magnetic pole near the earth's North Pole. The compass needle is equivalent to a magnet, and also has the Antarctic and Arctic points. The tip of the pointer is the south pole, and the other end of the pointer is the North Pole.