April 2017

STEAMcentric China

Ancient Earthquake Detector

Jane here, checking in from China.

My time in China has been exciting and full of adventure! The history, the land, and the people have fascinated me beyond my expectations. Before I head off to my next destination, I wanted to share with you one ancient item that can easily define "STEAMcentric" - the earthquake detector.

Zhang Heng was a renowned polymath that lived almost 2,000 years ago. He is credited as defining the calculation of pi (π) and improving the hydraulic systems for time keeping and power. His most intriguing invention was the "earthquake weathervain" or seismoscope.

Zhang's invention could detect which of the 8 cardinal directions an earthquake occurred, allowing the government to send help and aid to the affected regions hundreds of miles away. This elegantly made urn with ornate dragon figurines and toad receptors was an engineering marvel that to this day still holds its deepest secrets. It is known that a pendulum hung from the center, with 8 attached rods. The shock waves from an earthquake would activate the pendulum in such a manner that the activated rod would release a ball from the dragon's mouth into the wide open mouth of the toad, and a large tone would sound. What is not known is the exact setup inside the large urn. There have been many attempts to recreate the earthquake detector with varied outcomes but none that have been able to recreate with the precise accuracy that Zhang's invention had.

The earthquake detector is a beautiful, harmonious invention that was easy to use and helped to save lives in ancient China. The inner workings of this ancient technological wonder remain a mystery, but it is no mystery that Zhang engineered this machine using his observations and mathematics.

Until next time, Jane signing off.

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