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Noteworthy
Sophyphile


Registered: 10/05/08
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Sound in the Ocean
#14855998 - 08/01/11 11:34 AM (12 years, 9 months ago) |
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One may have noticed that entering a public pool opens one up to huge aural clairty of sounds from within the pool. Sounds from outside of the pool are distorted.
Turns out that sounds are carried better by dense matter compared to vacuous matter.
If we enter the ocean, various sounds might become apparent. Sounds travel further distances. This allows animals like dolphins and whales to communicate over large distances with their calls. They can even navigate the ocean by acoustically mapping the depths, presumably because their brains analyse eccho data.
What happens when we go even deeper into the ocean?
There are dark depths that continue to provide us with new discoveries. Most inspections seek to map the floor or attempt to give visual data.
I have not heard of 'the sound of the sea floor' but assumedly, as you get deeper, the water becomes more dense, limiting light transmission, but increasing sound transmission. Therefor everything that happens at the atlantic sea bed (for example) should be audible for very large distances.
Does anyone know anything about this? Are there investigations into the sounds of the sea floor?
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DieCommie

Registered: 12/11/03
Posts: 29,258
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I dont believe the water becomes much more dense. Water is very in-compressible, I would expect the difference in density to be negligible.
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Noteworthy
Sophyphile


Registered: 10/05/08
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Re: Sound in the Ocean [Re: DieCommie]
#14856072 - 08/01/11 11:49 AM (12 years, 9 months ago) |
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oh... right. Really? Even with the whole ocean on top?
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DieCommie

Registered: 12/11/03
Posts: 29,258
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Quote:
Noteworthy said: oh... right. Really? Even with the whole ocean on top?
That gives you high pressure, not high density. Water is very incompressible - meaning that high pressure does not affect density much. The factors that really play into water density is its temperature and how pure it is.
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Seuss
Error: divide byzero



Registered: 04/27/01
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> oh... right. Really? Even with the whole ocean on top?
Yes. Water is virtually incompressible. However, ocean water density is greater than fresh water density because of dissolved salts.
-------------------- Just another spore in the wind.
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Noteworthy
Sophyphile


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Re: Sound in the Ocean [Re: Seuss]
#14856096 - 08/01/11 11:55 AM (12 years, 9 months ago) |
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I see. And water pressure does not interact with sound?
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DieCommie

Registered: 12/11/03
Posts: 29,258
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Quote:
Noteworthy said: I see. And water pressure does not interact with sound?
Sound is water pressure, or more correctly - a periodic variation of pressure.
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Noteworthy
Sophyphile


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Re: Sound in the Ocean [Re: DieCommie]
#14856252 - 08/01/11 12:36 PM (12 years, 9 months ago) |
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well might the pressure at the bottom of the sea pulse in any way? does this happen? Does the churning of the sea floor resonate at any frequencies?
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Space Elf



Registered: 07/29/10
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I thought this was interesting:
Quote:
What created this strange sound in Earth's Pacific Ocean? Pictured below is a visual representation of a loud and unusual sound, dubbed a Bloop, captured by deep sea microphones in 1997. In the graph, time is shown on the horizontal axis, deep pitch is shown on the vertical axis, and brightness designates loudness. Although Bloops are some of the loudest sounds of any type ever recorded in Earth's oceans, their origin remains unknown. The Bloop sound was placed as occurring several times off the southern coast of South America and was audible 5,000 kilometers away. Although the sound has similarities to those vocalized by living organisms, not even a blue whale is large enough to croon this loud. The sounds point to the intriguing hypothesis that even larger life forms lurk in the unexplored darkness of Earth's deep oceans. A less imagination-inspiring possibility, however, is that the sounds resulted from some sort of iceberg calving. No further Bloops have been heard since 1997, although other loud and unexplained sounds have been recorded.
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koraks
Registered: 06/02/03
Posts: 26,729
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Quote:
Noteworthy said: well might the pressure at the bottom of the sea pulse in any way? does this happen?
Only if something moves the water. E.g. if the ocean floor would shake in a frequency that is within the audio spectrum.
Quote:
Does the churning of the sea floor resonate at any frequencies?
Earthquakes and tremors certainly move the ocean - but the frequency is usually pretty low; typically far below 20Hz, which is about the lowest frequency that is considered sound. So yes, but it's not exactly what you mean.
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Noteworthy
Sophyphile


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Re: Sound in the Ocean [Re: koraks]
#14859886 - 08/02/11 03:00 AM (12 years, 9 months ago) |
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Right -
to get to the heart of my inquiry
I am wondering about the cymatic properties of highly pressurised water.
I am wondering if the seafloor tremors create standing waves in the ocea or if they just send off noisy signals that quickly decohere
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debianlinux
Myconerd - DBK




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Sounds travels faster in water than in air. This has mostly to do with the proximity of the particles that comprise the medium (hence, the density).
The fun part of this is that the human brain has developed the appropriate degree of response to sound traveling in air not water. That is, the latency of sound reaching one ear before the other tells the brain the direction the sound is coming from. Underwater this latency is reduced below the threshold by which the brain can discern the difference. Thus, practically all sound is perceived to be in mono, overhead, between the ears.
This most easily observable by being submerged a few feet and listening to a passing motorboat. It will be impossible to determine the location and direction of travel of the boat without visual aid.
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koraks
Registered: 06/02/03
Posts: 26,729
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The presence of a standing wave doesn't depend on the pressure of the medium; it depends on the length of the channel and the wavelength. Due to the polymorphic nature of the ocean floor, a standing wave is unlikely to occur in that environment, although there are some examples of standing waves in rivers and fjords. They have little to do with tremors of the earth though.
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Seuss
Error: divide byzero



Registered: 04/27/01
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Quote:
debianlinux said: Sounds travels faster in water than in air. This has mostly to do with the proximity of the particles that comprise the medium (hence, the density).
The fun part of this is that the human brain has developed the appropriate degree of response to sound traveling in air not water. That is, the latency of sound reaching one ear before the other tells the brain the direction the sound is coming from. Underwater this latency is reduced below the threshold by which the brain can discern the difference. Thus, practically all sound is perceived to be in mono, overhead, between the ears.
This most easily observable by being submerged a few feet and listening to a passing motorboat. It will be impossible to determine the location and direction of travel of the boat without visual aid.
Although what you say is true, I have found that motor boats, for some unknown reason, are usually fairly clear as to what direction they are located. My guess is that their speed of travel, and possibly the doppler shift, help the brain to identify the direction. This is based upon my own observations, having spent multiple thousands of hours underwater scuba diving. For stationary noises, such as the clinking of an anchor chain, it is nearly impossible to tell what direction the sound is coming from.
One of my favorite noises is the snap-crackle-pop sound that parrot fish make as they eat away at the coral. Like most other sounds in the ocean, it appears to come from everywhere.
-------------------- Just another spore in the wind.
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Noteworthy
Sophyphile


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Re: Sound in the Ocean [Re: koraks]
#14870701 - 08/04/11 04:14 AM (12 years, 9 months ago) |
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Quote:
koraks said: The presence of a standing wave doesn't depend on the pressure of the medium; it depends on the length of the channel and the wavelength. Due to the polymorphic nature of the ocean floor, a standing wave is unlikely to occur in that environment, although there are some examples of standing waves in rivers and fjords. They have little to do with tremors of the earth though.
ok. Perhaps it could occur in an underwater cave? but i guess it would just be an accidental anomoly and would have minimal effects elsewhere
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koraks
Registered: 06/02/03
Posts: 26,729
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Exactly, that's what I would expect.
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