Sound & Hearing

Echo Tube

The echo tube is a 100 foot long cardboard tube sloping up almost to the roof of the Exploratorium. When the visitor claps his or her hands at the end, an echo is heard about 1/5 second later. The echo has a strange sound unlike the original clap (and much like the ricochet heard in old cowboy movies) due to the many different path lengths inside the tube. A rough estimate of the speed of sound can be made by timing the echo of the clap. (Sound travels about 1000 feet per second.)