Why is sound faster in warm air?
Name: Steve H.
Date: Around 1993
Why does sound travel faster in warm air than in cool air?
The warmer the air is the greater the average mean speed of the
molecules of air. Since sound is transferred by collisions of molecules, the
quicker they move the sooner the collisions transfer the sound energy down the
The traveling of sound depends on the forces between the atoms or
molecules of the medium, and in a gas those force only act during the short
period when they collide. But in liquids and solids the fundamental question
is how fast the atoms jiggle around in their local positions (sound waves are
actually coordinated long-wavelength "jiggles") which gets faster the higher
the strength of the local forces keeping the atoms roughly in place. So,
sound travels fastest in the most strongly bonded materials.
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Update: June 2012