If I set up two machines at the bottom of a body of water that was a hundred feet deep and installed two machines at opposite ends, one making no sound other than the whirring of its components and the other playing music through an amped up speaker as loud as it can be without being heard over 99 feet away, would the human ear hear any difference in the sound of the bubbles made by them?
Sound isn’t something that is specific to air. It’s merely the property of matter propagating a kinetic vibration wave which our ears/brain have evolved to “hear” within a certain range of hertz.
IOW, sound travels in helium, water, metal, concrete, air, wood, or any other form of matter. How far the material allows the wave (both frequency and amplification) to propagate (dampening) is mainly due to the density of the matter.
ETA: Bubbles aren’t necessary to generate sound underwater.
I’m having trouble visualising the setup. Are you just asking whether sound, underwater, would be altered by travelling through a curtain of bubbles?
If so, the answer is probably yes:
[ol]
[li]some of the sound waves will happen to travel direct paths that don’t interact with any bubbles and will arrive intact[/li][li]some will be transmitted (multiple times) through the bubbles and arrive a little later (speed of sound in air is slower than in water)[/li][li]some will be reflected off the surfaces of the bubbles (or refracted by the angle of the interfaces) and arrive via a comparatively roundabout route[/li][li]Some will be attenuated in the process of items 2 and 3 above, and will be fainter when it arrives.[/li][/ol]
In total, I’d expect this to result in the sound being more muffled and more quiet when it has to travel through the bubbles
In Hanna-Barbera physics, a trumpet played underwater will of course produce bubbles that pop with an ear-piercing parp at the surface.
The OP describes the first machine as
and the second machine as
And then the OP asked:
My question to the OP is: What bubbles? Which machine is making bubbles? The first? The second? Both? Neither? Like Mangetout, I can’t visualize the setup.
I don’t see much reason for the sound to travel through the bubbles at all. Sound travels a good deal faster through water than through air. Why would it slow down and hang around in a moving bubble?
Why wouldn’t it? It’s not like it’s exercising a conscious choice, and it’s not like lightning, where it just picks the best route.
I’m just curious as to why sound would stay in the bubble and then continue upward with the bubble instead of moving through or around the bubble.
When the sound wave hits a bubble, it will propagate through (I’m not sure what happens with sound propagation when it crosses over media boundaries like from water across the wall of the bubble; actually, the sound might not get into the bubble at all), but the bubble doesn’t carry the sound along with it as though it were a little sound bite transport device.
It wouldn’t stay in the bubbles, but it would go in, through and out (severely attenuated in the process, I expect)
The OP is referring to the case where both machines are generating bubbles, which then rise to the surface, where there is a human listener. One machine is also playing music, but not loudly enough to be heard at the surface without the aid of the bubbles. Will the bubbles enable the music to reach the surface and be heard by the listener?
To which the answer is no.
That sounds a fairly sane interpretation of the setup, but it still doesn’t make sense, because… what’s the purpose of the machine producing bubbles, and no music? I guess it could be a control experiment, but as the measurement in question is “can we hear the music”, it seems unnecessary.
I agree though, a column of water with bubbles in it should transmit music less well than a column of plain water.
Unless the bubbles are doing some strange resonance thing (which bubbles can in some cases - the ‘plink’ you hear when a raindrop hits a puddle is actually not the water hitting the water, it’s the sound of a tiny bubble snapping off the bottom of ‘crater’ as it rebounds)