I know that seems like a really stupid question but...I was thinking of something else, related to sound and suddenly realized that I have no idea why sound speeds away from an emitter at the speed of sound.
If I stand some distance from a rock face and loudly yell a "hello", that rather complex packet of information zips out to the wall and reflects back (delayed) as an echoed "hello". Okay, fine. The sound propagates at the speed of sound.
The usual reason given is that the adjacent air molecules vibrate and impinge on neighboring air molecules and the sound travels by that mechanism. And I have no quarrel with that...as a way to define why the air disturbances interact or the speed with which they do so in a given medium.
But, why does a "packet" of those disturbances propagate away from the emitter, intact? If the emitter is some sort of diaphragm that vibrates and moves the air back and forth just slightly, why doesn't the sound just stay there and become a more and more complex wveform with each cycle...with that cacaphony propagating,, by the interchange of energy between adjacent molecules, as basically a damped waveform as it loses energy with distance?
In other words...why does the sound packet speed away from the emitter? What propels it?
More important, is there a simple, 8th grade science class explanation of that reason?
If I stand some distance from a rock face and loudly yell a "hello", that rather complex packet of information zips out to the wall and reflects back (delayed) as an echoed "hello". Okay, fine. The sound propagates at the speed of sound.
The usual reason given is that the adjacent air molecules vibrate and impinge on neighboring air molecules and the sound travels by that mechanism. And I have no quarrel with that...as a way to define why the air disturbances interact or the speed with which they do so in a given medium.
But, why does a "packet" of those disturbances propagate away from the emitter, intact? If the emitter is some sort of diaphragm that vibrates and moves the air back and forth just slightly, why doesn't the sound just stay there and become a more and more complex wveform with each cycle...with that cacaphony propagating,, by the interchange of energy between adjacent molecules, as basically a damped waveform as it loses energy with distance?
In other words...why does the sound packet speed away from the emitter? What propels it?
More important, is there a simple, 8th grade science class explanation of that reason?
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