The Speed of Sound

Thunder, echoes and sonar

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Sound travels at about 343 m/s in air, 1,500 m/s in water and 5,900 m/s in steel.
• In air, $v \approx 331 + 0.6\,T$ m/s (T in °C).
• For an echo, the sound makes a round trip, so halve the total distance.

Steps

1. Air, water or steel?
2. Warm air is faster
3. A hot day
4. Count the thunder
5. Echo off a cliff
6. Sonar