The compass, papermaking, gunpowder, and printing are four great inventions by ancient Chinese people. These four inventions proved the development of Chinese civilization in ancient times which also had a far-ranging global impact.
In the Warring States Period, Chinese people invented a device called a Si Nan, which was the earliest south-north direction-pointing device. Si Nan was the forerunner of the compass.
By the time of the Tang dynasty and the beginning of the Northern Song Dynasty, Chinese scholars had devised a way to magnetize iron needles, by rubbing them with magnetite, and then suspending them in water. The compass was thus created. In the South Song Dynasty and continuing Yuan Dynasty, the dry compass was widely used in China. It was a wooden frame crafted in the shape of a turtle hung upside down by a board, with the lodestone sealed in by wax, and if rotated, the needle at the tail would always point in the northern cardinal direction.
During the Eastern Han Dynasty, a eunuch Cai Lun created a sheet of paper using mulberry and other bast fibres along with fishnets, old rags, and hemp waste. These raw materials could be easily found at a much lower cost so large quantities of paper could be produced. The technique of paper making was exported to Korea and Japan. By the 19th century, papermaking technique had spread to the whole world.
In Chinese, gunpowder is called huo yao, meaning flaming medicine. Unlike paper and printing, the birth of gunpowder was quite accidental. It was discovered in the 9th century while Chinese alchemists were searching for an elixir of immortality. Then people found out that a mixture of sulphur, saltpeter, and charcoal could produce a massive explosion. At the end of the Tang Dynasty, gunpowder was being used in military affairs. Later in the 12th and 13th centuries, gunpowder spread to all over the world.
During the Northern Song Dynasty, the common artisan Bi Sheng invented ceramic movable type printing after numerous tests. Single types were made and picked out for printing certain books. These types could be used again and again for different books. Because of the large number of different characters in the Chinese written language, this technique did not have a dramatic impact at the time. About 200 years later, this moveable-type technique spread to other countries and advanced the development of world civilization.
Celebrated in Chinese culture for their historical significance, these four great inventions are not only signs of ancient China's advanced science but also symbols of profound Chinese culture.