Compression of water (split from Waveguides)
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despotic931
diyAudio Member

Join Date: Jan 2008
Re: underwater HT

Quote:
 Originally posted by MJL21193 But don't you see what you are saying? What determines the temperature of an object? How much the molecules are moving. It is the heat produced by the friction of the molecules moving that determines its temperature. Every object has moving molecules (above absolute zero). These molecules are converting energy to heat. Where does the energy come from? The surrounding environment, an outside source. Take away the energy source and eventually the molecules will stop moving as they use up the remaining energy.
I never said that molecules were not in a constant state of motion. What should I "see" that I am saying? The energy comes from many many sources, including heat energy from surrounding matter. I don't see what this has to do with the current discussion.

I would like to hear you break down the events that take place as sound travels through water as per your theory much like I did in the post you were replying too. I want to know how displacement, heat, and expansion of volume all take place. I want to know their causes and the order they occur in. I want to hear "Aqueous Sound Transmissions According to John"!

Quote:
 Originally posted by MJL21193 What determines the volume an unconstrained object will occupy? Temperature and the surrounding pressure. Change the temperature while maintaining the pressure equates to a volume change. When you use energy to increase molecules motion this directly results in a volume change. It is not a "byproduct" but a direct result. There has been constant denial of the importance (and even the existence by a couple of well respected members) of this. It is more relevant than compression.
You should look up the definition of "byproduct", dictionaries are standard issue in elementary schools as far as I know.

byproduct: a secondary result, unintended but inevitably produced in doing or producing something else.

...it sounds to me that a byproduct IS a direct result. See this is how it works, the desired result is the transmission of sound through water, the byproduct is a minuscule increase in temperature which results in a microscopic increase in volume. However an increase in volume is not displacement!

If you have a pot of water filled to the brim and you place an object in it, it will overflow. If you take that same pot of water and set it to boil it will overflow. Each time the result was the same, however the means by which the end result was achieved was very very different!

Quote:
 Originally posted by MJL21193 BTW, quoting my original post is fine. The context is missing as this thread originated elsewhere. I have come to some more specific conclusion since then and I have Incorporated them into the mix. The end result is still the same: the primary mechanism for sound transfer through a medium is displacement, not compression.
You have nothing to back your claims up but fragmented facts and misguided ideas, but you are to stubborn to give them up, so instead you are talking in circles spouting random facts many of which are completely unrelated in an attempt to appear intelligent. Perhaps this is just out of a hope that if we perceive you as intelligent that we will simply believe you, or maybe it is a way of keeping away the "sharks" Sy was talking about (keeping them out of the conversation). Either way you have not proved anything, and the only thing you have managed to do is alienate yourself on a forum of your peers by the way you have handled many of the situations within this thread.

The main problem is that you keep jumping around instead of remaining on one point, and proving that point! I was on your side at the beginning of this thread, and was open minded enough to forget my views and opinions, but you just talked in circles and proved nothing. I know how sound travels through water John, but do you?

Quote:
 Originally posted by auplater So.. if I want to setup an underwater home theatre in my pool, what are some of the considerations I need to take into account? Maybe a drysuit if I'm listening and watching between 32F and 39F and a more powerful amp, eh?? For summer months, since the water will be expanding beyond the bounds of the pool at high listening levels, maybe I need some splash guards so the "sound doesn't escape"..??? After all, it could make "Flipper" much more realistic than plain ole 1080p... John L.
I will not be coming over to your house to watch "Jaws"...

-Justin

MJL21193
Account disabled at member's request

Join Date: Mar 2007
Quote:
 Originally posted by scott wurcer There is no volume change with temperature at 4C (water is still a liquid not "almost" ice BTW). So what parameter of sound in water is proportional to the change in density vs change in temperature?You can get off easy and not provide a complete mathematical framework just some simple proportionalities such as speed of propagation or attenuation vs distance. At 4C they either vanish or go to infinity. I think by your reasoning the zero change in density with temperature would actually make the attenuation increase exponentially as you approach 4C. Easily verifiable even in your kitchen.
You gave a Fahrenheit temp before and that confused me (the rest of the world has moved on to metric). My earlier post assumed the water was frozen solid.

What are you getting at? At 4*C, water is at it's maximum density at standard pressure. Use sound energy to excite the molecules and they will expand the volume. Temperature change, density change, volume change.

Quote:
 Originally posted by scott wurcer "The temperature of water in the surface goes on decreasing to 0 degree C & finally is converted into ice, while the water below the ice continues to remain at 4 degree C. As water remains at 4 degree C, fish & other aquatic animals remain alive." And presumably keep on singing to each other.

??? Are you losing it?

 12th September 2008, 04:54 AM #403 dnsey   diyAudio Member   Join Date: Mar 2004 Location: Shropshire, England First principles again: Archimedes gets into his bathtub. A certain amount of water, equivalent to the volume of his body, is moved (dis-placed) from its original position in the tub onto the floor, since both Archimedes and the water cannot take up that space at the same time. So far, so good. In a second experiment, Archimedes lights a fire under the tub. The water expands, and some of it overflows onto the floor. It has not been displaced (in the scientific sense of the word), since the tub remains entirely full of water. However, I suspect that you, John, would use the word 'displaced' to describe what happens to the water in the second case. Here is an example of the need to apply strict definition of terms to avoid confusion and misunderstanding. (A further point - as a good physicist, Archimedes will, no doubt, ensure that the temperature in the first experiment remains constant, so that he can be sure that all the water on the floor is a result of displacement, and not of expansion.) ***** Not directly related to the above - a thought experiment (or a practical one, if you want to...): Set up an acoustic transmitter and receiver either end of a vessel filled with water. Observe the transmission of sound from transmitter to receiver, by (according to you) a mechanism whereby the energy input heats the water locally , which expands, and is thus 'displaced' - is this a fair summary? Now place a cooling coil in the vessel, and use it to extract exacly as much heat as is being added to the system by the transmitter. What is observed at the receiver? Why?
 12th September 2008, 10:31 AM #404 Ed LaFontaine   diyAudio Member     Join Date: Feb 2004 Location: where the Appalachians rise from the Blue Grass the argument holds no water John, I think many of us see that water expands with decreasing temperature just above freezing. I think many of us see that the converse of this...water density increases along with temperature in this small range...is also true. I think many (probably all) of us see that you are unable to resolve another apparent conflict with your compression/temperature/density morphism of the moment. I think you have been the recipient of a great deal of well intended effort put forth by eminently talented people. I think your lack of acceptance has...by your own actions...placed you in a position where you can expect less sincere help in the future, maybe when you need it more. I hope you get what you need. I don't think you will find it here. __________________ ...call me Ed...Special Ed... EnABL kit http://www.diyaudio.com/forums/swap-meet/119852-enabl-kit.html DCB1 parts http://www.diyaudio.com/forums/swap-...ml#post2361098
MJL21193
Account disabled at member's request

Join Date: Mar 2007
Quote:
 Originally posted by dnsey First principles again: Archimedes gets into his bathtub. A certain amount of water, equivalent to the volume of his body, is moved (dis-placed) from its original position in the tub onto the floor, since both Archimedes and the water cannot take up that space at the same time. So far, so good. In a second experiment, Archimedes lights a fire under the tub. The water expands, and some of it overflows onto the floor. It has not been displaced (in the scientific sense of the word), since the tub remains entirely full of water. However, I suspect that you, John, would use the word 'displaced' to describe what happens to the water in the second case. Here is an example of the need to apply strict definition of terms to avoid confusion and misunderstanding.
Yes, you have it in a nutshell. The same result - the water overflow is happening by (almost, use your imagination) the same mechanism - molecules are pushed out of the way and the volume that the water occupied increases. I know, in the first you are adding mass and the second you are adding energy but the end result is the same - displacement.
My use of "displacement" has be used in a specific context, and I thought that there would be no confusion. As usual, I was wrong.

Quote:
 Originally posted by dnsey Set up an acoustic transmitter and receiver either end of a vessel filled with water. Observe the transmission of sound from transmitter to receiver, by (according to you) a mechanism whereby the energy input heats the water locally , which expands, and is thus 'displaced' - is this a fair summary? Now place a cooling coil in the vessel, and use it to extract exacly as much heat as is being added to the system by the transmitter. What is observed at the receiver? Why?

The cooling coil is performing a separate task and will have no effect on the transmission of sound. The same thing is happening - displacement and volume increase from the sound energy.
All that the cooling coil is doing is drawing the same amount of energy out of the water. This does not interfere with the first process.
The end result is no volume expansion and no temperature change. Sound was still transmitted though.

MJL21193
Account disabled at member's request

Join Date: Mar 2007
Re: Re: underwater HT

Quote:
 Originally posted by despotic931 I never said that molecules were not in a constant state of motion. What should I "see" that I am saying? The energy comes from many many sources, including heat energy from surrounding matter. I don't see what this has to do with the current discussion.
It's the very definition of what I'm saying! When energy is used in a medium heat is produced. This heat is produced by the increased molecular movement. It doesn't matter where the energy comes from as long as it is kinetic. When a medium or any other object heats up, it expands. This is the displacement I am talking about. This is the expansion that I'm talking about.

Quote:
 Originally posted by despotic931 I would like to hear you break down the events that take place as sound travels through water as per your theory
I'm working on it...

MJL21193
Account disabled at member's request

Join Date: Mar 2007
Re: the argument holds no water

Quote:
 Originally posted by Ed LaFontaine John, I think many of us see that water expands with decreasing temperature just above freezing. I think many of us see that the converse of this...water density increases along with temperature in this small range...is also true.

You sure about the above? Doesn't water expand below freezing? We know it expands above freezing, everything expands with increased temperature.
Wouldn't the density decrease as the volume expands?

scott wurcer
diyAudio Member

Join Date: Jan 2004
Location: dorchester ma
Quote:
 Originally posted by MJL21193 What are you getting at? At 4*C, water is at it's maximum density at standard pressure. Use sound energy to excite the molecules and they will expand the volume. Temperature change, density change, volume change. ??? Are you losing it?
NO!

At 4C there is no change in density with temperature in fact at 3.5 C the density goes the other way. Average back and forth around 4 C and there is no net change in density no volume change. Asymptote, slope of zero remember?

OK look at it another way. There is a dramatic difference in the rate of change in density with temperature around 4 C, in fact it changes sign. There are no corresponding changes in the propagation properties of sound.

Heat flow obeys diffusion laws. The time constant determined by the thermal capacity and thermal resistance are orders of magnitude less than the speed of sound propagation (in general). The solutions to diffusion equations also do not support traveling waves.
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 12th September 2008, 12:09 PM #409 auplater   diyAudio Member     Join Date: Apr 2005 Location: KyOhWVa tristate Can you say "Topper"? This looks to be a variation on the "Topper Syndrome", as in "That's nothing, lemme tell you about MY STORY..." http://7akifadi.com/2007/06/26/the-topper-syndrome/ mangled into the format of "whatever you say or demonstrate to the contrary or to refute what I say, I'll re-define whatever you thought I was saying to something with a new set of rules, thus proving whatever you said or demonstrated is/was irrelevent to whatever it is that you thought I meant> Justin... Not even if I supply a titanium shark cage??? John L. __________________ "I've forgotten more than I care to remember" The Last Conspirators
amiklos
diyAudio Member

Join Date: Jan 2007
Re: Re: the argument holds no water

Quote:
 Originally posted by MJL21193 You sure about the above? Doesn't water expand below freezing? We know it expands above freezing, everything expands with increased temperature. Wouldn't the density decrease as the volume expands?
He was talking about the small range from 0-4 degrees C. As water warms from say 2C to 3C, it's density actually increases toward the maximum at 4C. Since this would be a contraction in volume, it seems to preclude sound propagation in this narrow range if that propagation is (as I believe you suggest) dependent upon molecules moving, creating heat, and causing expansion.

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