Sound Pipes

Principle of Science: Speed of Sound

Observe a long, coiled pipe circling back to its starting point. A mouthpiece is fitted at one end and an earpiece at the other. Speak into the mouthpiece and note the delay in time that occurs before they hear the sound in the earpiece. Since the length of the pipe is known, measure the time of the delay and estimate of the speed of sound.

Most of us have heard the term “speed of sound.” We may also know that a jet plane exceeding the speed of sound (a “supersonic” aircraft) makes a “sonic boom” as it goes by, or that the crack of a lion tamer’s whip is caused by the tail of the whip exceeding the speed of sound. But here in the everyday world, just how fast does sound travel?

During the next thunderstorm, try to calculate the distance to a bolt of lightning by noting the time lag until the clap of thunder is heard.