WORLD HISTORY

Detailed explanation-1: -Blast furnaces were invented by the Han Dynasty around 200 BCE. Blast furnaces would pump air into heated iron ore and transform the iron into cast iron. Better iron led to better weapons and tools. Seismographs, a tool used to detect earthquakes, were developed by scientist Zhang Heng in 132 CE.

Detailed explanation-2: -The Han invented paper and lead-glazed ceramics, and greatly improved silk-weaving techniques. Their quest for alliances with foreign powers prompted them to establish an extensive trade route that extended to the Roman Empire and would become known as the Silk Road.

Detailed explanation-3: -Papermaking, printing, gunpowder and the compass-the four great inventions of ancient China-are significant contributions of the Chinese nation to world civilization. China was the first nation to invent paper.

Detailed explanation-4: -The compass was invented in China during the Han dynasty between the 2nd century BC and 1st century AD where it was called the “south-governor"(sīnán ) or “South Pointing Fish” (). The magnetic compass was not, at first, used for navigation, but for geomancy and fortune-telling by the Chinese.