In fact, the magnet in people's mouths is not a stone itself, nor is it pure iron. In ancient times, the natural magnets used by people to manufacture compasses were mostly composed of iron oxide, iron oxide, and many other impurities. In fact, besides iron, magnetite can also attract metals such as nickel and cobalt, but these two metals are too rare in daily life. For a long time, people only knew that it can absorb iron, so they directly named it magnetite and continue to use it today.

At that time, people were not sure why magnets generated magnetic force, and even regarded magnetic force as a divine force. With the development of science, especially the discovery of the law of electromagnetic induction, people finally discovered the mystery of magnetic force generated by magnets.

According to Ampere's law, a magnetic field is generated near the current, and the strength of the magnetic field changes with the current. The greater the current, the stronger the magnetic field. In high school, there have been scientific experiments using an energized solenoid to generate a magnetic field. During the experiment, the direction of the magnetic field will also follow the right-hand spiral theorem, which changes with the direction of the current. At the macro level, electric current generates a magnetic field, and natural iron magnets do not have electricity or current.