There are many simple electric imaginations, such as 1. Electrification: The property that can attract light and small objects is called object electrification.
2. Friction electrification: the object is electrified by friction.
1) Two kinds of charges: There are only two kinds of charges in nature: positive charge and negative charge.
2) the provisions of the positive and negative charges
Positive charge: the charge carried by a glass rod rubbed with silk.
Negative charge: the charge carried by a rubber rod rubbed with fur.
3) Charge interaction: charges of the same kind repel each other and charges of different kinds attract each other.
4) Electroscope: According to the principle that like charges repel each other, check whether the object is charged.
3. Conductors and insulators
1) conductor: an object that conducts electricity easily.
Such as: metal, graphite, human body, soil and various aqueous solutions of acid, alkali and salt.
2) Insulator: an object that is difficult to conduct electricity.
Such as: rubber, glass, ceramics, plastics, oil, pure water, sugar water, alcohol and so on.
China's understanding of electricity in ancient times began with the phenomenon of lightning and friction electrification. As early as 3000 years ago in Shang Dynasty, there were pictophonetic characters of "thunder" and "electricity" in Oracle Bone Inscriptions. In the early Western Zhou Dynasty, the word "electricity" appeared next to the word "rain" on bronzes.
Wang Chong in On Balance? Xu Lei wrote: "When clouds and rain come, thunder will shock you", and clearly put forward the relationship between clouds and lightning. In the following ancient books, there are abundant descriptions of lightning and its disasters, especially in the Ming Dynasty, Zhang (1525 ~ 1582) described the size, shape, color and appearance time of lightning fireballs in detail, leaving reliable and precious written materials.
While observing carefully, people are also discussing the causes of lightning. Huainanzi? "Descending Training" holds that "Yin and Yang are as thin as thunder and as excited as electricity", that is, lightning is the product of the opposition between Yin and Yang. Chong Wang also holds a similar view. In the Ming Dynasty, Liu Ji (131~1375) put it more clearly: "People who thunder are depressed and excited. When the yang is trapped in the yin, it will be forced and exploded. The sound is thunder and the light is electricity. " It can be seen that at that time, some people realized that thunder and lightning were different manifestations of the same natural phenomenon.
Tip discharge is also a common electrical phenomenon. The weapons in ancient times were mostly spears, swords and halberds, but the sharp blades of spears and halberds often led to the occurrence of tip discharge, because this phenomenon has been described. For example, Hanshu? There was a fire at the spear end in the Middle Yuan Dynasty (AD 3) in the Western Regions, and it was also described in the Jin Dynasty's Search for Ji Shen: "All halberds have flames, as far as candles." Lightning rod is a specific application of tip discharge. In ancient China, various measures were taken to prevent lightning strike. The spire of ancient pagodas is often plated with metal film or gold, and the tiles of high-rise buildings are made into animal shapes and installed in the sky, which all play the role of lightning protection. For example, on the top of the main peak of Wudang Mountain stands a golden palace, which has a history of more than 500 years. Although it stands above the mountain peak, it has never been struck by lightning. Jin Dian is an all-copper building, and the top design is very exquisite. Except for the ridge decoration, the curvature is not too big, so the ridge decoration plays the role of lightning rod. Whenever there is a thunderstorm, there is a huge potential difference between the clouds and the Golden Temple, and an arc is generated through the discharge of the ridge ornaments, which makes the air expand rapidly and the arc deforms like a huge fireball. At that time, the thunder was earth-shattering, lightning danced like a golden snake, and a huge fireball jumped and rolled at the top of the Golden Temple, which was spectacular. After the thunderstorm, the Golden Temple became more glittering after being washed by water and fire. Such ingenious lightning protection measures are amazing.
Through careful observation, the ancients in China accurately described the effects of lightning on different substances. There is a detailed record of lightning strike in the Book of Southern Qi: "Lei Zhen Huiji Hengshan Lin Bao Temple broke its brakes four times, and the pagoda was burned by electricity, but the windows were the same." It is a powerful discharge current that passes through the metal film on the Buddha's face and melts completely. The window is made of wood and remains the same. Shen Kuo described a similar phenomenon in more detail in Meng Qian's Bi Tan: "Li Shun, a domestic servant, was shocked by thunder. In the west room of the hall, thunder and fire came out from the window and from the eaves. People thought that the main room had burned down, so they all went out to hide. And thunder, * * * now. Walls, windows and paper are precious. There is a wooden lattice, which is mixed with all kinds of utensils. The lacquerware is silver, and the silver has melted and flowed to the ground. The lacquerware is not in a hurry. There is a treasure knife, extremely strong steel (steel), which turns into juice in the knife room, and so does the room. People will say that fire burns vegetation first, and then stones flow. Today, the stone is full of stones, and no vegetation is destroyed, which is not measured by human feelings. " In fact, this phenomenon only happens because lacquerware and knife room are insulators, while Baodao and silver buckle are conductors.
In China, the phenomenon of triboelectrification has been described a lot, and the materials commonly used in the early days were mostly amber and tortoiseshell. As early as the Western Han Dynasty, there was a record in Chunqiuwei that "the hawksbill (hawksbill) sucked (small things)". In Lun Heng, there is also "Dunmou", and Dunmou here also refers to tortoise shell. When I was a teenager, I heard that "the tiger soul can't pick up the rotten mustard." Rotten mustard becomes a conductor because it contains water, so it will not be attracted by charged amber. Amber is expensive and people are often confused. Tao Hongjing in the Southern Dynasties knew that "it is true to pick up mustard by rubbing it with the palm of your hand", and took it as the standard to distinguish true amber from false amber. In the Northern and Southern Dynasties, Lei Biao wrote in the "Canzang Theory" that "amber blood is like blood, and it is true to rub it with cloth and suck mustard seeds". He changed others' hand friction into cloth friction, which greatly increased the electrostatic attraction. Zhang Hua (232 ~ 300) in the Western Jin Dynasty described the phenomenon that the friction between comb and silk produced discharge and sound: "When people comb their hair and take off their clothes, some of them untie with the comb and some hiss." The paragraph in the Tang Dynasty describes rubbing the skin of a black cat in the dark to generate electricity: "If the cat is black, it will secretly follow its fur, that is, if it is Mars". Triboelectrification also has specific applications. According to Zhang Bangji's Mo Zhuang Man Lu in Song Dynasty, the emerald broom made of peacock hair can attract borneol (organic debris that can be used to make spices). After that, the jade feather swept it away, and everyone gathered, and there was no survivor. "There are many records about triboelectrification.
Modern electricity is developed on the basis of a large number of records and understanding of lightning and friction electrification. The study of electricity by ancient scholars in China greatly enriched people's understanding of electricity. In modern times, the understanding of electricity has become richer and deeper, and various power generation machines and equipment have been developed, which has made electricity more widely used and made great contributions to human progress.