Author Topic: A Vaccum  (Read 2703 times)

The_Q_Man

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A Vaccum
« on: July 02, 2006, 08:03:51 PM »
I've always wondered whether or not a vaccum would effectively reduce sound in a room. For example, if you stuck a speaker in a thermos, would you hear it? I assume it would, because the sound waves wouldn't be able to be transferred as well, but I'll leave it to the experts to answer, since you guys probably know :)

johnbergstromslc

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Re: A Vaccum
« Reply #1 on: July 02, 2006, 08:18:05 PM »
If by "vacuum", you mean an absence of air molecules, well, since airborne sound is a vibration of air molecules, then no sound can traverse a vacuum.  

If you stuck a speaker in a thermos (a vacuum bottle) you would hear it because the vibrations would be transferred mechanically and vibrate the whole bottle (there is a connection between the inner and outer bottles at the top of the thermos.)  This is called 'structure-borne' sound.  

To try to reduce sound in a room with some kind of vacuum would be folly.  You'd have to turn the whole room into a vacuum chamber (so much for breathing...).   A container pulling a vacuum placed in the middle of the room would create a nice dead spot and would absorb some sound, but overall it wouldn't be practical.  

 

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