Zhang Heng

Zhang Heng was a Chinese scientist who lived about 2000 years ago. He is famous for several inventions, including a seismograph, which was a machine that could detect earthquakes. The seismograph was made up of parts like jars, a container of water, and rods that measured movement. When an earthquake happened, the jars would knock over, which caused the container of water to move and the rods to show movement. This showed scientists that an earthquake had occurred and where it had happened. Zhang Heng was also one of the first people to give an accurate description of the Earth's surface in a paper called "A Treatise on the Earth". He is remembered as an important figure in science, who made important inventions and discoveries.