Both thermal energy and air are propagated through vibration of particles so why sound does not heat up the air e.g loud musical instrument does not generate much heat ?
[Physics] Why sound does not heat up the air
acousticsthermodynamicsvibrations
acousticsthermodynamicsvibrations
Both thermal energy and air are propagated through vibration of particles so why sound does not heat up the air e.g loud musical instrument does not generate much heat ?
Best Answer
Sound waves do generate changes in temperature because the propagation of sound is an approximately isentropic process. Keep in mind though that changes in static temperature can very well occur without the generation of heat. Moreover, the pressure changes associated with sound waves are of such a small magnitude that the observable temperature changes are minimal (but non-zero). In fact, when Isaac Newton first attempted to derive the speed of sound, his answer was off by almost 15%, precisely because he assumed that the propagation of sound was an isothermal ($\Delta T=0$) instead of isentropic ($\Delta S=0$) process. In short, sound waves do alter the temperature of the surrounding medium, just not by that much.