The twenty-four solar terms, papermaking, the compass, gunpowder, and printing.
1. 24 solar terms
The 24 solar terms, which are the 24 specific seasons in the solar calendar, are based on the Earth's position in the ecliptic, the orbit of the Earth around the Sun, and each of the 24 solar terms corresponds to a certain position in the ecliptic for every 15° of the Earth's movement.
The twenty-four solar terms are a system of knowledge formed by observing the annual movement of the sun and recognizing the patterns of change in the seasons, climate, and physical phenomena of the year. It divides the annual movement of the sun into 24 equal parts, each of which is a solar term, beginning with the beginning of spring and ending with the end of the great cold, and the cycle repeats itself again and again.
In the international meteorological community, the 24 Solar Terms are regarded as "China's fifth great invention".
2, papermaking
Paper is the accumulation of long-term experience and wisdom of the ancient Chinese working people, it is an outstanding invention in the history of human civilization.
China was the first country in the world to raise silkworms and weave silk. Ancient Chinese working people used top quality cocoons to weave silk, and the rest of the cocoons, sick cocoons and other cocoons were used to make silk by bleaching method.
After bleaching, the gabion mat will leave some residual floss. When bleaching more often, gabion on the residual wool will accumulate into a layer of fiber flakes, after drying peeled down, can be used for writing.
The byproduct of this bleaching is small in number, and in ancient books, it is called Hejian or Fangwu. This shows that the origin of papermaking in ancient China is related to silk floss.
3, compass
Compass, called Sinan in ancient times, the main component is a magnetic needle mounted on a shaft, the magnetic needle in the natural geomagnetic field can be free to rotate and remain in the tangential direction of the magnetic meridian, the magnetic needle of the North Pole pointing to the geographic North Pole, the use of this property can be identified direction.
The compass is the result of the ancient Chinese working people's understanding of the magnetism of magnets in their long-term practice. As one of the four great inventions of ancient China, its invention has played an immeasurable role in the development of human science and technology and civilization. In ancient China, the compass was first used in rituals, ceremonies, military and for determining directions in divination and feng shui.
4, gunpowder
Gunpowder, also known as black powder, from potassium nitrate, charcoal and sulfur mechanical mixture. It is a substance that can carry out rapid and regular combustion by itself under the action of appropriate external energy, while generating a large amount of high-temperature gas.
In the military is mainly used as gunpowder, artillery shells, launching agents and rockets, missiles, propellants and other driving devices of energy, is an important part of the ammunition. Gunpowder is one of China's four great inventions, which also changed the history of human warfare.
5, printing
Printing is one of the four great inventions of the ancient Chinese working people. Engraving and printing was invented in the Tang Dynasty and was commonly used in the middle and late Tang Dynasty.
Bi Sheng invented movable-type printing during Song Renzong. Although movable-type printing appeared in the Song Dynasty, it was not in general use, and engraving was still commonly used.
Printing was the forerunner of modern human civilization, creating conditions for the wide dissemination and exchange of knowledge. Printing was successively spread to Korea, Japan, Central Asia, West Asia and Europe.
Baidu Encyclopedia - Twenty-four Seasons
Baidu Encyclopedia- -The Four Great Inventions