The Qin and Han dynasties witnessed further advances of science and culture based on the great leap in pre-Qin period and the consequent prosperous situation featuring all-around cultural development.
1 Paper-making technique
The invention of the paper-making technique was the most prominent contribution made to human civilization. Chinese characters first appeared on pottery, tortoise shells and bronze ware, and later on bamboo slips and silk cloth, which were either heavy or expensive and made cultural spreading difficult. In the early Western Han Dynasty, workmen, while beating pods into silk, occasionally found that characters could be written on the remaining silk membranes. Enlightened by the process, the Chinese people adopted flax as raw materials to produce the earliest plant fiber paper, which was still rough and not suitable for writing. In the Eastern Han Dynasty, the eunuch Cai Lun resorted to tree barks, fax cloth, rags, old fishing nets and other raw materials that were easy to acquire to make quality but cheap paper, which were called "Marquis Cai Paper." From then on, paper was produced on a large scale and became the most popular material for writing.
China's paper-making technique was first exported to Korea and Vietnam, and then to Japan in the 7h century, to Arabian counties in the 8th century and further to Europe in the 12th century. That played a significant role in worldwide cultural spreading, accumulation and communication, and had a profound impact upon the progress of world civilization.
2 Other techniques
The iron-smelting sector of the Han Dynasty remained as advanced as before. Quenching techniques were invented and coal was used as the fuel for smelting. In the Eastern Han Dynasty, wind power was utilized in metal smelting, and a low-temperature steel-making technique was invented and. popularized as well. With regard to ship-making, more efficient sculls, more flexible stern steering wheels, cloth sails relying on wind power and firmer anchors were invented, leading to improved navigation techniques. With regard to the handicraft sector, the superb black porcelains made in the late Eastern Han Dynasty marked the maturity of porcelain-making techniques that were first initiated in China. Improving silk embroidery workmanship resulted in more diversified categories of embroideries with exquisite patterns and bright colors that were exported to East Asia and Europe in large quantities and reputed by the Romans as "the world's No.1 fabrics." With regard to measuring celestial bodies, Zhang Heng of the Eastern Han Dynasty invented the earliest "armillary sphere" that revolved with hydraulic power. He also invented a seismograph that could precisely measure the direction of earthquakes that occurred thousands of miles away—more than 1,700 years earlier than similar devices invented in Europe.
3 Mathematical achievements
Unlike Greek classical mathematics that focused on theorem proving, ancient Chinese mathematics centered on algorithm creating, especially algorithms on solving equations. The Zhou Bi Mathematical Manual finished in the Western Han Dynasty, first records a special case in geometry known as Pythagorean Theorem, about 500 years earlier than that proposed n the west. The Nine Chapters on Mathematical Art written during the Eastern Han Dynasty was a collection of mathematical achievements from pre-Qin to the Han Dynasty, and was respected as the most important book of algorithms. The book records all the algorithms on practical problems closely related to production, including those about land areas, grains, trade, warehouse sizes, earthwork and tax, and summarizes ways of calculating positive and negative numbers and solutions of quadratic equation. Its presence marked the formation of the ancient Chinese mathematical system in which counting rods were used as the calculation tool and the decimal system was adopted. The book was introduced to Japan in the Sui and Tang dynasties, and some parts of the book were spread to India and the Arab world, and even to Europe.
4 Classic medical books
Many famous doctors and classic books emerged in the Han Dynasty. The Yellow Emperor's Classic of Internal Medicine during the Western Han Dynasty was a fundamental book of traditional Chinese medical theory. The book, which was comprised of two parts, had 162 articles in 18 volumes. It discussed basic theories concerning the body, physiology causes of diseases, and diagnosis, as well as acupuncture, channels and collaterals, and health care. Emperor Shen Nong's Materia Medica written during the Eastern Han Dynasty was a summary of drug use since the Warring States Period and laid a foundation for subsequent Chinese pharmacology. Zhang Zhongjing, known as the "Medicine Saint" in the Eastern Han Dynasty, proposed a set of traditional Chinese theories in The Treatise on Febrile Diseases, including the three causes of diseases, and treatment according to syndrome differentiation. Hua Tuo, a highly skilled doctor in the Eastern Han, invented Mafeisan, the earliest surgical anesthetic, performed the first abdominal cavity operation in China, and invented the five-animal health care exercise.
Against the backdrop of unification, the official mainstream ideology in the Qin and Han dynasties experienced a transformation process from "contention of a hundred schools of thought" to "paying supreme tribute to one thought while banning all ways of spreading other schools of thought." The thought of legalists in the Warring States was adopted by Emperor Ying Zheng as a sharp tool pushing for the reform and, based on abandoning Confucianism and absorbing part of the diverse thoughts of many schools, further became the dominant ideology guiding the politics of the Qin Dynasty after the unification.