Sound — Describe

Describe a method for determining the speed of sound in air using measurements of distance and time.

Two people stand a large, accurately measured distance apart. One makes a loud sound (e.g. bangs two blocks of wood together or fires a starting pistol) while the other starts a stopwatch on seeing the action and stops it on hearing the sound. The speed of sound is calculated using speed = distance / time; repeating and averaging the readings, or using a longer distance, reduces the effect of reaction-time errors.