phelpio

I was thinking about how all energy normally degrades into heat, such as in the resistance of electric current, friction in kinetic energy or how light is absorbed into a surface and warms it. Does this happen with sound? Of course i googled it and found this answer page: Here Some people have stated that sound energy keeps spreading out uniformly to infinity, some people think that it will degrade to a form of low level heat energy.. none state any references.. But.. If a 2000w speaker was placed within a bottle in a vacuum so no sound energy can escape, will the sound eventually heat the surrounding area by some method? or would this sound continually spread out and just become 'background noise'? This would mean that all sound that has ever been generated is still around, uniformly spread out.. Or... could the molecules moving as a sound wave collide and cancel each other out? e.g. two cars hitting each other head on at 30mph and coming to a dead stop. but the caloric theory states that energy cannot be created or destroyed.. Also as sound is a mechanical pressure wave would the molecules through the medium the wave is travelling in would be subject to friction and create heat? I'm confused!!! Phelpio