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Speed of Sound

Speed of sound is how fast a clap or shout travels through the air to reach your ears.

Think of it this way

Tap a glass on the counter and the sound wave moves through the air. It travels about 1,100 feet each second. Tap a glass at one end of a long table. The person at the far end hears it a tiny moment later.

Explaining speed of sound by grade level

When you clap your hands near a big wall, you hear the sound come back. That bounce-back sound is called an echo. The sound has to travel to the wall and back again. It moves fast, but not so fast that you can't notice the small wait.

Projects that explore speed of sound

Echoes and Measuring Sound Speed

You can measure how fast a shout travels the same way you time a runner on a track. Stand a known distance from a large flat surface, fire a starter's pistol, and start a stopwatch at the same moment. When the echo returns, stop the watch and divide twice the distance by the time. At room temperature you should get about 344 meters per second. At freezing, the speed drops to about 331 meters per second — a measurable change from a simple drop in temperature.

Medium