Chinese Seismograph Vase
For centuries different societies have designed many creative ways to measure the shaking of the earth. Nearly 2000 years ago, for example, the ancient Chinese made a special vase that had several sculpted dragons mounted all around the sides of the vase. Each dragon held in its mouth a metal ball. When the ground shook, some of the balls would fall from the mouths of the dragons into the waiting mouths of the sculpted frogs to show how the ground had moved. (courtesy of National Geographic magazine)