What are the five great inventions?

The five great inventions refer to the 24 solar terms, papermaking, compass, gunpowder and printing.

1, 24 solar terms

Twenty-four solar terms refer to 24 specific festivals in the solar calendar that represent seasonal changes. It is formulated according to the change of the earth's position on the ecliptic (that is, the earth's orbit around the sun), and each solar term corresponds to a certain position that the earth reaches every time it runs 15 on the ecliptic.

Step 2 make paper

Paper is the crystallization of the long-term experience and wisdom of the working people in ancient China, and it is an outstanding invention in the history of human civilization. China is the first country in the world to raise silkworms and weave silk. In ancient China, the working people spun silk from superior cocoons, and the remaining evil cocoons and diseased cocoons were made into silk floss by bleaching. This kind of floc is called "He Qi" or "square floc" in ancient books because of its small number of by-products. This shows that the origin of ancient papermaking in China is related to silk floss.

3. Compass

Compass, called Sina in ancient times, is mainly composed of magnetic needles installed on the shaft. Under the action of natural geomagnetic field, the magnetic needle can rotate freely and keep in the tangential direction of magnetic meridian. The north pole of the magnetic needle points to the geographical north pole, and we can use this property to identify the direction.

4, gunpowder

Gunpowder is made of potassium nitrate, charcoal and sulfur by mechanical mixing. It is a substance that can burn quickly and regularly under the action of appropriate external energy, and at the same time produce a large number of high-temperature gases.

Step 5 print

Printing is one of the four great inventions of working people in ancient China. Engraving printing was invented in the Tang Dynasty and was widely used in the middle and late Tang Dynasty. In Song Renzong, Bi Sheng invented movable type printing. Although movable type printing appeared in Song Dynasty, it was not widely used, while block printing was still widely used.