Sound travels roughly four times faster through water than it does through ordinary air.

The longer version

Sound is a travelling disturbance that passes from particle to particle. In water the molecules sit much closer together and interact more strongly than the spread-out molecules of a gas, so each one hands the vibration onward sooner. The disturbance therefore covers the same distance in far less time.

Temperature, salinity and depth all shift the exact value, and sound also loses less energy in water, which is why it carries over long distances. Marine animals rely on this property, and so do ships measuring depth. The pitch of a voice does not affect the speed, only the spacing of the waves.

Where this entry sits

Everyday physics and chemistry hide small wonders in plain sight, from kitchen reactions to the light in the sky. These short facts explain matter, energy, electricity, magnets, sound, and the simple units we use to measure the world. The full list sits on the Science and Physics page, where every entry is listed in order.