Sound moves faster through water than through air, and faster still through solid steel.

The longer version

Wave speed depends on how stiff a material is and how heavy it is. Stiffness passes a disturbance along quickly; heavy particles resist being accelerated and slow it down. Water is far harder to compress than air, so it hands the push along more briskly. Steel is stiffer still, and its atoms sit close together.

Roughly, vibrations cross water several times faster than air and cross steel faster again. Workers on old railways could detect a distant train by pressing an ear to the rail well before the noise arrived through the air. Underwater, that speed makes direction hard to judge, since the wave reaches both ears almost together.

Where this entry sits

Sound and Music gathers facts about how vibrations move through air and water, how ears turn them into meaning, and how instruments and notation shape what listeners hear. Expect echoes, pitch, volume, acoustics, and the odd silence in between. The full list sits on the Sound and Music page, where every entry is listed in order.