/sreten.
ongoing denial
Maybe it's like this "honorable mention" excerpt from Wiki..
"One 'Honorable Mention' (a man who attempted suicide by swallowing nitroglycerine pills, and then tried to detonate them by running into a wall)"
http://en.wikipedia.org/wiki/Darwin_Awards
or perhaps this:
http://pinkfluffydust.livejournal.com/36518.html
Maybe it's like this "honorable mention" excerpt from Wiki..
"One 'Honorable Mention' (a man who attempted suicide by swallowing nitroglycerine pills, and then tried to detonate them by running into a wall)"
http://en.wikipedia.org/wiki/Darwin_Awards
or perhaps this:
http://pinkfluffydust.livejournal.com/36518.html
Re: name calling?
Yes, no one should be beaten on!
I didn't get any lame emails! I don't think John is crazy, or dumb, or anything bad. He just has a different idea about the way that something takes place, and granted he has yet to prove that idea imo, that doesn't mean that he believes it any less. I am confused about why he started by saying compression did not take place when sound traveled through water then switched to stating that a small amount of compression does take place. As much as he seems to believe that our idea of the way sound travels through water is wrong, he doesn't seem to be so set in his own idea of how sound travels through water.
I hope not!
Sheldon said:
Yes, no one should be beaten on!
auplater said:
I didn't get any lame emails! I don't think John is crazy, or dumb, or anything bad. He just has a different idea about the way that something takes place, and granted he has yet to prove that idea imo, that doesn't mean that he believes it any less. I am confused about why he started by saying compression did not take place when sound traveled through water then switched to stating that a small amount of compression does take place. As much as he seems to believe that our idea of the way sound travels through water is wrong, he doesn't seem to be so set in his own idea of how sound travels through water.
scott wurcer said:
I hope not!
scott wurcer said:
Not quite.
scott wurcer said:
We are talking about how sound travels through a medium, not how it is first introduced. Impedance match has nothing to do with this "discussion".
scott wurcer said:
Very well, but the pressures involved are in the microPascal range (typical sound wave).
scott wurcer said:
scott wurcer said:
So, it is your contention that NO displacement takes place? Explain what happens to the energy that is dissipated in the medium.
How can a medium dissipate energy without a temperature change?
MJL21193 said:
It all scales, it does not matter at all even nano Pascals. All lossy media attenuate a traveling wave by heat. One of those excellent references probably has a discussion re: water. RF waves propagate in a vaccum essentialy losslessly.
You accept the classical formula for the speed of sound, so think of a whale making a 20Hz sound and compute the wavelenth and then the energy to displace that much water.
scott wurcer said:
What happens to a medium when energy is dissipated by heat? Volume change (increase)?
So, it stands to reason that as sound travels through a medium the volume that this medium will occupy will increase. This is the definition of displacement.
scott wurcer said:
How does a whale make sound?
A whale modulates the water pressure by pushing it through its blowhole. This, if I'm not mistaken, is similar to the way a pump would work by pressurizing the water.
As mentioned earlier, water can be pressurized without significant density change. Take the pressure changes at depth in the ocean - constant increase as you go down. Water can flow despite this pressure (current).
More later....
sreten said:
Well, it isn't obvious to the majority of contributors to this thread, judging by what I have read. The given explanation for sound to travel through a medium is by compression and rarefaction, with no displacement or volume increase.
The standard explanation: As the sound wave moves through the medium, it pushes adjacent molecules closer together (compression), leaving a space behind (rarefaction).
Even though one member here suggested that at the end (after the sound has passed through the medium) the overall density of the medium would increase (occupy less volume), most here seem to believe that the medium will conduct the sound energy without a change to the original state (volume) of the medium.
They say that no displacement takes place.
To get this straight, here's what I mean by "displacement": In order for the medium to accommodate the increased motion of the molecules as they are excited by the energy input, the volume that the medium occupies will increase. This is reasonable to expect if there are no constraints on this volume expansion. I have been saying that this requires less energy to achieve than to push molecules closer together. I have been saying that this is the primary mechanism for sound energy transfer through the medium.
Yes you have been saying it a lot, but you've only been saying it. You have no evidence whatsoever. What do you hope to achieve by constantly claiming the entire world is wrong about how waves travel? (the entire world except you that is)
It does seem logical that the tiny amount of energy dissipated in water by a passing sound wave would warm the water up some extremely hard to measure amount, but linking that to your claim that sound doesn't travel by compression wave is another silly argument that wouldn't fly in even a high school debate. "A" is true, and I mentioned "A" and "B" in the same post, so B must be true?"
just knock it off already this thing has been disproved to death. Maybe you should take up tennis or something else healthy?
poptart said:
The evidence is there. How do you do work (energy transfer) in a medium without heat being produced?
Increased motion = more friction = temperature rise. Heat equals expansion.
So, maybe you have the answer: Explain what happens to the energy that is dissipated in the medium.
How can a medium dissipate energy without a temperature change?
poptart said:
Maybe you should try being less belligerent and insulting.
You don't own the principles that we are discussing here. You are not the author of the concept I'm challenging.
Why get so upset?
sreten said:
Density variation occurs.
Take a bowl of water. Add sound energy. As explained above, energy dissipation = heat; heat equals expansion. Density decreases.
Take a steel ruler. Add energy by bending it. Energy in = heat = expansion. Density decreases.
In both cases, displacement is the answer. Molecules are displaced and the volume increases.
nor do you own them or this forum. I'm not personally insulted, I just think you're playing games with the people of this forum and I'd like to know what the real goal of that game is.
Somehow you commented on the beginning and end of my post without reading the middle where i actually agreed with you, but so what? Does saying the *average* density of a large volume of water changes one way or another prove that there are no local variations in density? No. It's a totally different issue AND it says nothing about your claim that sound doesn't travel by compression wave.
Somehow you commented on the beginning and end of my post without reading the middle where i actually agreed with you, but so what? Does saying the *average* density of a large volume of water changes one way or another prove that there are no local variations in density? No. It's a totally different issue AND it says nothing about your claim that sound doesn't travel by compression wave.
MJL21193 said:
This is trivial, patronising and a distortion of the truth. As ever, you focus on displacement to the exclusion of all else.
The primary mechanism in this case (thermal expansion) is the increased inter-molecular distance resulting from increased vibration. Yes, this results in displacement, but what you have written suggests displacement is the prime cause. Displacement is a result.
It is commonplace to ascribe cause to those events preceeding results.
You need to revisit thermodynamics.
w
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