What is the speed of sound?

Bam! With an explosion, a fighter jet flies through the sound barrier. From that moment on, the plane travels at faster than the speed of sound. But how fast? What actually is the speed of sound?

Sound travels faster in dry summer air

Sound consists of waves. The time it takes for this sound wave to travel a certain distance is the speed of sound. In dry air at twenty degrees Celsius, the speed of sound is 343 meters per second, or 1,234 kilometers per hour.

But the speed of sound is not constant. This depends, among other things, on air temperature and humidity. In cold air, the sound wave moves slower because the molecules in the air vibrate more slowly. Because the density of moist air is lower, sound will travel through it faster.

The speed of sound varies between liquids and solids. Sound waves travel faster through water than through air, about five times faster. Through solid materials, think of an iron tuning fork, sound accelerates at over 1,500 meters per second.

What is the maximum speed of sound?

Researchers from Queen Mary University of London calculated in 2020 Under the best conditions, the absolute maximum speed of sound is 129,600 kilometers per second. That's more than three times around the world in a single heartbeat.

It sounds very fast, but compared to the extreme speed of light, it sounds like a slow turtle. Light flies through space at the speed of a rabbit, at 300,000 kilometers per second.

Within the atmosphere you can see the difference between the speed of light and sound best during thunderstorms. Flash, there's lightning… wait a minute… and then thunder. But do you know exactly how far away a thunderstorm is if you calculate the time in between?