Four Great Inventions
The Four Great Inventions of ancient China were the compass, paper-making, printing, and gunpowder. These were hallmark achievements of ancient Chinese civilization that had a profound impact on the progress of human civilization.
The compass is an instrument used to determine direction. As early as the Warring States period (475-221 B.C.), the Chinese invented the "Si Nan" spoon compass, based on a natural magnet's ability to point to the north and the south. This was the world's earliest form of compass. In the Song Dynasty (960-1279), people made compasses with artificially magnetized iron needles, which were widely used in naviga- tion. Between the late 12th century and the early 13th century, the compass was introduced to the Arab world and Europe, enabling European navigators to explore new routes.
Paper is closely related to daily life. Before its invention, the Chinese used shells, animal bones, bamboo and wooden slips, silk, and other materials for writing. Papermaking was invented in the early the Western Han Dynasty (206 B.C. - A.D. 25). Unearthed in 1986, a fragment of a paper map dating back to the time of Emperor Wendi of the Western Han Dynasty is the earliest known piece of paper. During the Eastern Han Dynasty (A.D. 25-220), Cai Lun improved the papermaking process. Between the 3rd and the 4th century, paper became the most important writing material in China. From the late 4th century, the art of papermaking spread to Korea and Japan, and later to Europe through the Arab world, especially Egypt. Papermaking was a milestone in the development of writing materials, which effectively facilitated the preservation and dissemination of culture.
Ancient Chinese printing technology underwent two stages: woodblock printing and movable type printing. Woodblock printing, invented in the Tang Dynasty (618-907), was a process of printing texts and images with ink by first carving them onto wooden blocks. This technique had its roots in seal engraving and rubbing copies of inscriptions on stone tablets. During the Northern Song Dynasty (960-1127), Bi Sheng invented movable typeset printing. His method used movable clay type pieces, which reduced costs and increased efficiency. This invention appeared 400 years earlier than Johannes Gutenberg's movable metal typeset printing in Germany. During the Song and Yuan dynasties (960-1368), China developed multi-color printing. Ancient China's printing technology spread eastward to Korea and Japan and westward via the Arab world to Africa and Europe, paving the way for the development of science and the Renaissance in Europe.
Gunpowder, a black or brown explosive substance derived from alchemy, was invented in the Sui and Tang dynasties (581-907). There are records of gunpowder production from the middle of the Tang Dynasty. By the end of the Tang Dynasty, gunpowder was being used for military purposes, leading to the development of new weapons such as cannons and rockets.
By the time of the Song Dynasty (960-1279), firearms were commonly used in battles. Gunpowder spread to Arab countries via India and then to Europe and other parts of the world. Firearms gradually replaced cold weapons and had a revolutionary impact on war tactics and fortification construction, and many other aspects of technological and social development, accelerating the progress of human civilization.
四大发明
中国古代四大发明，即指南针、造纸术、印刷术、火药。四大发明是中国古代文明的标志性成就，对人类文明进程产生了深远影响。
指南针是用以判别方位的一种仪器。早在战国时期，中国人根据天然磁石指示南北的特性制成了“司南”，这是世界上最早的指南仪器。两宋时期，人们发明了用人工磁化铁针制成指南针的方法，并广泛应用于航海。12世纪末至13 世纪初，指南针传入阿拉伯和欧洲，为欧洲航海家探索新航路提供了重要条件。
纸与人类日常生活息息相关。在纸发明之前，中国人曾把贝壳、兽骨、竹片、木片、丝绸等作为记录文字的载体。西汉初年，中国人发明了造纸术。1986年出土的西汉文帝时期的纸质地图残片，是迄今发现的人类社会最早的纸。东汉时期，蔡伦改进了造纸术。3至4世纪，纸成为中国最主要的书写材料。从4世纪末开始，造纸术逐渐传往朝鲜、日本，后经阿拉伯、埃及传入欧洲。造纸术是人类书写材料的伟大革命，有力促进了文化的保存和传播。
中国古代印刷术分为雕版印刷和活字印刷两个阶段。唐代发明的雕版印刷术，是把图文刻在木板上用水墨印刷， 其前身是印章捺印和拓印碑石等。北宋时期，毕昇发明的活字印刷术，主要使用胶泥活字降低印刷成本同时提高效率， 这比德国谷腾堡（1398—1468）的铅活字印刷术早约400 年。宋元时期，中国出现了套色印刷技术。印刷术发明后， 向东传到朝鲜、日本，向西经由阿拉伯传播到非洲和欧洲， 为欧洲科学发展和文艺复兴运动提供了重要物质条件。
火药起源于炼丹术，是隋唐时期炼丹家发明的一种黑色或棕色的炸药。唐代中期已经有关于火药制作的记载。唐代末年，火药开始被运用于军事，出现了火炮、火箭等新式武器；到了宋朝，火器普遍用于军事战斗。火药经印度传入阿拉伯国家，再传到欧洲乃至世界各地。火药兵器逐步取代了冷兵器，在战争战术、攻城筑城等技术发展和社会进步方面产生了革命性影响，推动了世界历史发展的进程。
