Four great inventions of China
compass
One of four great inventions of ancient china. Pointers made by using the north-south finger polarity of magnets in the earth's magnetic field have many shapes. During the Warring States period, magnets were found to attract iron, and natural magnets were used to make "SiNa spoon" and "its handle guide". After a long period of practice, it was found that the method of artificial magnetization led to a higher level of magnetic director. Shen Kuo, a scientist in the Song Dynasty, first recorded the geomagnetic declination, saying that rubbing a steel needle with a natural magnet to magnetize it into a magnetic needle can be used as a guide, but it tends to be slightly eastward. He also introduced four methods of supporting and hanging the magnetic needle: first, floating on the water; second, putting it on a nail; third, putting it on the edge of a bowl; and fourth, hanging it with a wire.
Song Jun is equipped with a kind of guide fish, which judges the direction of cloudy days and nights by cutting thin iron leaves into the shape of fish and magnetizing them. Later, it developed into a compass with a magnetic needle and an azimuth disk, that is, a compass. Zeng Sanyi recorded in Records of Yin Hua that there was a Rorty who was also a water compass. At that time, Yin and Yang used Luo to watch Feng Shui. Land is also used to clear fields and adjudicate land litigation. According to historical records, the compass was used for navigation at the latest in the late Northern Song Dynasty. In the Southern Song Dynasty, the "dial" was used for navigation. This dial also uses "floating needle", which has played a great role in the development of maritime traffic and economic and cultural exchanges between China and foreign countries.
make paper
China invented it in ancient times. Outstanding achievements in the history of human civilization. China is the first country in the world to raise silkworms and weave silk. The ancients spun silk from superior cocoons, and bleached the remaining evil cocoons and diseased cocoons to make silk floss. After floating, some residual flocs will be left on the mat. When the flossing frequency is high, the residual flossing on the pad will accumulate into fiber sheets, which can be peeled off after drying and can be used for writing. This kind of floc is called "He Qi" or "square floc" in ancient books because of its small number of by-products. It can be seen that the origin of papermaking in China is related to silk floss. Cai Lun invented papermaking in the first year of Yuan Xing in the Eastern Han Dynasty (105). He made paper from plant raw materials such as bark, hemp head, cloth, fishing net, etc., through crushing, ramming, papermaking and baking, which is the origin of modern paper. Since the invention of papermaking, paper has entered the social and cultural life with a new attitude, and gradually spread in China, and then spread all over the world.
gunpowder
A mixture with saltpeter, sulfur, charcoal or other combustible substances as the main components can burn or explode quickly after being ignited. The first explosive mastered by mankind, one of four great inventions of ancient china. Because saltpeter and sulfur were both drugs in ancient China, they were easily ignited and burned violently after being mixed, so they were called gunpowder. Modern black powder is developed from ancient gunpowder in China. It has played an important role in the development of world culture. Gunpowder originated from ancient alchemy in China. Gemmological drugs used by ancient chemists (alchemists), such as nitrate and sulfur, were mastered as early as the Han Dynasty. After a long-term practice of alchemy, they invented gunpowder three years before Yuanhe (808) in Tang Xianzong at the latest, and used it to make gunpowder weapons for arson at the end of the Five Dynasties and the beginning of the Northern Song Dynasty (10 century). In the practice of constantly creating new firearms in the Song and Yuan Dynasties, the performance of gunpowder was constantly improved, and gunpowder for bombs and propellant for metal tube firearms were manufactured, which reached a mature level in the Ming Dynasty. In Qi Jiguang's Book Ji Xiaoxin, the formula and manufacturing technology of gunpowder are described in detail.
Print in type
typeset and print
One of four great inventions of ancient china. Carve it into a single word first, then piece together each word into a whole page according to the crop, and then watermark it with ink. Bi Sheng, a civilian in Song Renzong in Qing Dynasty, invented movable type printing on the basis of the popularization of block printing. Carving words with clay makes calligraphy and painting stand out, each word becomes a seal separately, and it is hardened with fire to make a word seal. In addition, the iron plate is coated with drugs made of turpentine, wax and paper ash. When printing, arrange the words one by one, embed them in an iron plate, bake them with fire, slightly dilute the medicine, and then press them on the words with a flat plate to make the plate flat. After the medicine is solidified, it can be printed. This early type printing method already has the basic process of modern printing-casting, typesetting and printing. It is 400 years earlier than a set of movable type printing technology created by J. Gutenberg in Germany in the middle of15th century.