Who discovered magnetism? What's the short story?

In the pre-Qin period, our ancestors had accumulated a lot of knowledge in this field. When exploring iron ore, they often encountered magnetite, that is, magnetite (mainly composed of ferroferric oxide). These findings have long been recorded. These discoveries were first recorded in several articles in Guanzi: "There are magnets on the mountain and gold and copper under it." There are similar records in other ancient books, such as Shan Hai Jing. The iron-absorbing characteristics of magnets have long been discovered. The main chapter of the nine volumes of Lu's Spring and Autumn Annals is: "Kindly absorb iron, or absorb it." At that time, people called "magnetism" "kindness". They think that magnets attract iron is the attraction of loving mothers to their children. And think: "Stone is the mother of iron, but there are two kinds of stones: kind and unkind. Kindness can attract his children, but not kindness. " It is said that after Qin Shihuang unified the six countries, Epang Palace was built near Xianyang. There is a door made of magnets in the palace. If someone wears armor and hides weapons to assassinate in the palace, they will be attracted by the magnet door. This story tells us that the ancient working people mastered the knowledge of magnetism very early.

Before the Han Dynasty, people wrote magnets as "Ci Shi", which means to love stones.

Since magnets can attract iron, can they attract other metals? Our ancestors made many attempts and found that magnets can not only attract metals such as gold, silver and copper, but also attract bricks and tiles. During the Western Han Dynasty, people realized that magnets could only attract iron, but not other objects.

When two magnets are put together and close to each other, sometimes they attract each other and sometimes they repel each other. Now people all know that magnets have two poles, one is called N pole and the other is called S pole. Like-sex repulsion, opposites attract. People didn't know this truth at that time, but they could still perceive this phenomenon.

In the Western Han Dynasty, there was an alchemist named Luan Da. He used this characteristic of magnet to make something similar to two chess pieces. By adjusting the mutual position of the polarities of two chess pieces, sometimes the two chess pieces attract each other and sometimes repel each other. Luan Da called it "playing chess". He dedicated the novel to Emperor Wu of the Han Dynasty and gave a live demonstration. Emperor Wu of the Han Dynasty was pleasantly surprised. He was named "General Five Blessingg". Luan made great use of the properties of magnets to make novel things to deceive Emperor Wu of Han Dynasty.

The earth is also a big magnet, and its poles are close to the geographical south pole and the geographical north pole respectively. Therefore, when the magnets on the earth's surface can rotate freely, they will represent the north and south because of the nature that magnets repel each other with the same polarity and attract each other with the opposite polarity. The ancients did not understand this truth, but they knew this phenomenon very well.