The story of Zhang Heng's invention of seismograph

Zhang Heng was an outstanding scientist in the Eastern Han Dynasty. He loves to think since he was a child, and he always wants to get to the bottom of everything around him.

One summer night, Zhang Heng, grandpa and grandma were enjoying the cool in the yard. He sat on the bamboo bed, upturned his head, looked blankly at the sky, raised his fingers from time to time and counted the stars carefully.

Zhang Heng said to grandpa, "I counted for a long time and saw some stars moving. What was in the sky has gone to the west. Some stars appeared and some disappeared. Aren't they running? "

Grandpa said, "The stars will move. If you want to know the stars, you must look at the Big Dipper first. Look at the seven bright stars over there. Together, it's like an iron for ironing clothes. It is easy to find ... "

"oh! I found it! " Xiao Zhangheng was very excited and asked, "So, how does it move?"

Grandpa thought for a moment and said, "About midnight, it moved to the horizon. At dawn, Beidou turned over and hung upside down in the sky ... "

That night, Zhang Heng couldn't sleep and got up many times to see Beidou. In the dead of night, he saw the bright big dipper hanging upside down. How happy he feels! He thought: Why does this Beidou turn like this? What is the reason? At dawn, he hurried to ask grandpa, who couldn't explain it clearly. So, with this question, he went to read astronomical literature.

Later, when Zhang Heng grew up, the emperor learned that he was outstanding in literary talent, so he called Zhang Heng to Luoyang, the capital, as an imperial adviser, mainly in charge of astronomical calendars.

In order to explore the mysteries of nature, young Zhang Heng often studies alone in his study and often stands on the observatory to observe the sun, moon and stars. He thought, if we can make an instrument that can observe the sky from above and the earth from below, and predict what will happen in nature, it will be of great help to people to prevent disasters and expose those absurd superstitious stories!

Therefore, Zhang Heng analyzed and studied the observation data from books, and began the trial production of the instrument of "observing the sky and the earth". He first wrote a book about his research called Lingxian. In this book, he tells people that the sky is spherical, like an egg, the sky is like an eggshell, wrapped outside the ground, and the ground is like an egg yolk. This is the so-called "Huntian Theory".

Then according to this theory, Zhang Heng began to design and manufacture instruments. I don't know how many stormy mornings and sleepless nights passed, when the armillary sphere, one of the most advanced astronomical instruments in the world, was born. This big copper ball is very similar to today's globe. It is mounted on an inclined shaft. Through hydraulic rotation, its rotation speed is exactly the same as that of the earth. On this artificial celestial body, you can see the stars in space accurately. Zhang Heng said: "There are 2,500 stars in the sky, but we often only see 120."

Later, after studying hard, Zhang Heng invented and created the world's first instrument that can predict earthquakes-the seismograph. This seismograph is also made of steel, shaped like a wine jar, surrounded by eight dragons, and each longkou contains a small copper ball. As long as the copper ball in the dragon's mouth spits out, it means that there is an earthquake in that direction. The test was very effective, and there was no failure.

Zhang Heng's creation and invention in science is great because he loved science since childhood, studied diligently, observed experiments persistently, and was able to combine book knowledge with practical experience and obtain it through his own hard research and creation.