Index Key:  PHY067
Author:     Steve H.
Subject:    Why is sound faster in warm air?
Text:      Why does sound travel faster in warm air than in cool air?

Response #:  1 of 2
Author:      gfb
Text:        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 
path.

Response #:  2 of 2
Author:      A. Smith
Text:        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.