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Old 28th July 2008, 09:22 AM   #131
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Quote:
Originally posted by despotic931


Ok, this is me trying to keep an open mind and understand what you are saying...

In a sound wave molecules are not compressed but rather displaced? Where do the displaced molecules go? What happens to the water that has overflowed onto the floor?

Finally!
Sound energy moving through the water will cause the molecules to move. Increased movement causes a temperature change due to friction - the temperature will increase.
Understanding that a material will expand when heated (due to increased molecule movement), we can expect the overall volume that the water occupies will increase. This is where the displacement shows - in the volume increase.

This increase in temperature and volume are very small, as the amount of energy in a sound wave is relatively small.
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Old 28th July 2008, 09:37 AM   #132
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Originally posted by Sheldon


Based on grade school understanding (your term), or to a layman with no training in physics, acoustic compression waves in water might not be obvious. But many people have tried to explain how it works, have pointed to detailed descriptions of the mechanism, given experimental evidence, relevant equations and constants to calculate the movement of acoustic pressure waves in water, against which nothing that can be mathematically derived or computed, in fact no citations of any kind which support the proposed alternative mechanism. What is ridiculous?
But that is what this is - grade school understanding. There isn't any need to complicate what I am saying. You bring in a bunch of other factors that have absolutely no bearing on what I am saying, either to cloud the issue or because you don't fully understand what I am saying.
Read my response to despotic931 above and see if you can understand the meaning of it. It's simple.
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Old 28th July 2008, 01:56 PM   #133
Daveze is offline Daveze  Australia
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Quote:
Originally posted by MJL21193



Finally!
Sound energy moving through the water will cause the molecules to move. Increased movement causes a temperature change due to friction - the temperature will increase.
Understanding that a material will expand when heated (due to increased molecule movement), we can expect the overall volume that the water occupies will increase. This is where the displacement shows - in the volume increase.

This increase in temperature and volume are very small, as the amount of energy in a sound wave is relatively small.
What manner of movement? In a particular direction or just moving more? Heat is the second but you need the first in order for sound to travel in a sensible manner.

Suppose you are right...thought experiment conducted on a long rectangular tank of water, signal generator at one end, receiver at the other, bound on three length sides, open at the top to atmosphere: create pulse at one end, should expect to receive sound at the other. However the displacement will occur through the top of the tank, not at the other end where we would expect to hear the sound.

Furthermore, suppose we have a very long tank: does the entire top surface displace at once? It cannot, that would be matter exceeding the speed of light, which is impossible (remember when I 'evoked' Einstein...). Suppose it doesn't displace at once and what we see is a ripple of displacement, which then demonstrates a sound on our receiver at the other end. The problem with this is that the ripple does not move at the speed of sound measured for water (~1500m/s) but moves with a velocity much lower.
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Old 28th July 2008, 02:43 PM   #134
Sheldon is offline Sheldon  United States
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Originally posted by MJL21193
But that is what this is - grade school understanding.
I guess we were hoping we could get you beyond that. Good luck folks.

Sheldon
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Old 28th July 2008, 03:13 PM   #135
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Quote:
Originally posted by MJL21193



Finally!
Sound energy moving through the water will cause the molecules to move. Increased movement causes a temperature change due to friction - the temperature will increase.
Understanding that a material will expand when heated (due to increased molecule movement), we can expect the overall volume that the water occupies will increase. This is where the displacement shows - in the volume increase.

This increase in temperature and volume are very small, as the amount of energy in a sound wave is relatively small.
Ok, so the sound causes the molecules to move, this causes heat, which then causes displacement due to molecular expansion? In a tank of water this displaced water goes up, I am guessing because air is easily compressed by water? Also this displacement will travel with the sound wave, correct? Therefor according to your theory a body of water with a sound wave passing through it will display a greater volume than one without a sound wave (this is of course assuming we could measure the volume of this tank at a molecular level)?

Now, If I am understanding you correctly:

According to your theory an enclosed airtight container, holding nothing but water (I want to stress this, there is no air or anything else in this container, just water) at a pressure of one atmosphere, could not carry a sound wave? I am assuming this because for that water to carry a sound wave some of the molecules would have to be displaced, and that would cause a compression of molecules around the area of displacement. Suddenly you would have sound waves creating compressions and rarefactions (areas of displacement if you will), am I not correct?

-Justin
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Old 28th July 2008, 08:46 PM   #136
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Pressure will still bear, but unless there's enough, it will not compress.
If you don't come up with some cites to back the above fabrication up, you are effectively conceding that you don't have a clue what you're talking about.
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Old 28th July 2008, 08:50 PM   #137
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Out of curiosity, what education, title, or career do you have that has allowed you to make such discoveries?
He says he 'figured it out' in a grade school playground. Of course, he's changing his 'understanding' an awful lot right now.
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Old 28th July 2008, 09:10 PM   #138
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It's still going huh?

You're making a lot of noise about nobody really reading your arguments but you haven't responded to any of the very real arguments put to you either. Number one being the speed of sound. If you took the time to think about that you'd have no choice but to understand what's going on.

So we have a little nano-tube that's filled with water molecules all in a line. You push on one end of the line and it takes a small amount of time for that impulse to reach the other end. Explain this without accepting elasticity, I dare you. I triple dog dare you even!
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Old 29th July 2008, 12:57 AM   #139
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Quote:
Originally posted by Daveze


What manner of movement? In a particular direction or just moving more? Heat is the second but you need the first in order for sound to travel in a sensible manner.

Suppose you are right...thought experiment conducted on a long rectangular tank of water, signal generator at one end, receiver at the other, bound on three length sides, open at the top to atmosphere: create pulse at one end, should expect to receive sound at the other. However the displacement will occur through the top of the tank, not at the other end where we would expect to hear the sound.

Furthermore, suppose we have a very long tank: does the entire top surface displace at once? It cannot, that would be matter exceeding the speed of light, which is impossible (remember when I 'evoked' Einstein...). Suppose it doesn't displace at once and what we see is a ripple of displacement, which then demonstrates a sound on our receiver at the other end. The problem with this is that the ripple does not move at the speed of sound measured for water (~1500m/s) but moves with a velocity much lower.

The movement of the molecules is parallel to the source of energy. They would move in opposition to the force applied. The movement is slight, and they "tend" to return to their relatively original position afterwards - this is why I said "vibrate" earlier, as in oscillate, but this isn't exactly correct. This movement transfers energy to the next molecules by pushing.
The problem with a liquid, such as water, is there is loss of transfer efficiency through it. The molecules are not lined up neatly like in a metal such as steel, and the molecules have a tendency for random movement. This relates to the low elastic properties of water. This is why sound travels through water at a lower speed than steel.
Displacement will be an overall volume increase. The energy introduced from the sound wave is fairly small (for normal audio, for instance), therefore the charges will be small. They will still be there though.
The pressure and temperature within the medium has changed producing a slight change in volume.
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Old 29th July 2008, 01:37 AM   #140
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Quote:
Originally posted by despotic931


Now, If I am understanding you correctly:

According to your theory an enclosed airtight container, holding nothing but water (I want to stress this, there is no air or anything else in this container, just water) at a pressure of one atmosphere, could not carry a sound wave? I am assuming this because for that water to carry a sound wave some of the molecules would have to be displaced, and that would cause a compression of molecules around the area of displacement. Suddenly you would have sound waves creating compressions and rarefactions (areas of displacement if you will), am I not correct?

-Justin

You are understanding me correctly - just you so far.

To be honest, I'm curious about that myself. I assume you are talking about a tank that has infinitely stiff sides that will not flex and a sound wave source inside the tank, surrounded by water (like a driver fastened in the middle of the tank to a divider with holes in it to allow water move from front to back).

It stands to reason that if what I am saying is correct, sound will not travel through it, as the molecules need room for movement and the energy from the driver does not provide sufficient force to compress the molecules closer together.
The rarefaction phase of the wave would not work either, as there is no room for the volume increase that results from a density decrease.
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