Chinese Water ClocksDue: Oct. 19

By: Deonte Williams

Ancient Water ClocksA Chinese is an ancient time measuring

apparatus by the amount of dripping water. In China, water clocks are very important of astronomy and astrology.

The Oldest DatesThe oldest reference dates the use of the

water clock in China to the 6th century BC.[16] From about 200 BC onwards, the outflow clepsydra(or “C”) was replaced almost everywhere in China by the inflow type with an indicator-rod borne on a float.

Zhang SixunIn 976, Zhang Sixun(or Z) addressed the

problem of the water in clepsydrae freezing in cold weather by using liquid mercury instead.[18] Again, instead of using water, the early Ming Dynasty engineer Zhan Xiyuan (c. 1360-1380) created a sand-driven wheel clock, improved upon by Zhou Shuxue (c. 1530-1558).

Huan TanHuan Tan (40 BC–AD 30), a Secretary at the

Court in charge of clepsydrae, wrote that he had to compare clepsydrae with sundials because of how temperature and humidity affected their accuracy, demonstrating that the effects of evaporation, as well as of temperature on the speed at which water flows, were known at this time.

Who Invented The Water Clock?Su Song was fascinated with clocks. He

wondered how they worked. So he decided that he’ll try to make one himself. He tried to think out the box. He tired everything that he can do.

Problems With ClockSu-Sung got around that problem. His huge

clock stood 40 feet high and was powered by a special water wheel. Buckets around its rim were filled, one at a time, by a steady flow of water. When each bucket was heavy enough to trip a mechanism, it fell forward -- carrying the bucket behind it into place under the water spout. And the process repeated.

How To Measure Water ClocksThere are approximately two types of water

clocks in term of how time is measured. One is a holed container filled with water that measures the time by dripping the water outside. It's called "dripping water clock". The other is a container (with no holes at the bottom) that measures the time by letting water drip inside. It's called "filling water clock".

Web Stieshttp://history.cultural-china.com/en/58History

2802.html

http://www.uh.edu/engines/epi120.htm

http://en.wikipedia.org/wiki/Water_clock