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Post by speakertoanimals on Feb 14, 2011 16:54:05 GMT 1
No they don't. It is the attenuation of different frequencies that changes, hence if higher frequencies are lost, it may sound lower in pitch.
Temperature will effect the resonant frequency of a wind instrument, because that depends on the length and the speed of sound. Hence brass sounds a bit off in hot climes! But that ISN'T the same as changes in density effecting the pitch of sound waves themselves.
Plus its BLOODY OBVIOUS that the frequency MUST stay the same. Suppose I have a box containing high-density air, and elastic membrane, and a second box containing lower density air. Sound waves in the air cause the membrane to vibrate at the SAME frequency as the pressure waves (lets ignore resonance and all that). And that membrane causes the air on the other side to vibrate as well. And the whole things has to stay in step, so the frequency of the vibrations is unaltered, even though the speed (hence wavelength) will depend on the medium.
So Carnyx, your comment is usual, utter and total bollocks! Or could be you don't know the difference between frequency and wavelength...................
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Post by carnyx on Feb 14, 2011 20:22:45 GMT 1
STA,
you are so very wrong on this one!
1, Take an emitter, producing a single frequency in a medium.
2. Arrange a steady reductionincrease in density of the medium with distance.
3. The frequency will drop/rise with distance from the source.
It is quite difficult to find an instance of a continuous medium that changes density with distance, so here is a thought experiment;
A man blows a very loud single-frequency air horn at the bottom of the mountain, which can be heard at the top. A nearby microphone picks up the sound and it is relayed to a loudspeaker at the top of the mountain .
The experiment can only start when the air temperature at the top and bottom of the mountain are the same.
Will the two sounds at the top of the mountain be heard at the same frequency?
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Post by speakertoanimals on Feb 14, 2011 21:39:58 GMT 1
Except ALL the physics sources I can find state quite clearly that what alters with temperature is speed of sound, NOT frequency then, but wavelength.
The confusion arises because the pitch of an instrument (such as an organ) DOES change -- but NOT because the pitch changes as the speed of sound changes!
In an organ, the wavelength produced is fixed (depends on length of organ pipe), hence for a fixed wavelength, pitch will be higher if the speed of sound increases. BUT this does not mean the pitch changes AGAIN if you now let that sound into a room where air temperature is different again.
As I keep saying, you don't need to get complicated, vibrations can be `transmitted from the air, to a metal rod, through some complicated apparatus, and back into a helium gas tank, if you like, but since the vibratuions stay in step, the frequency/pitch remains the SAME, even though the speedof transmission varies greatly.
As I also said, with real horns, different frequencies attenuate differentlym, hence overall it will sound different, but pitch remains the same, just that the mix of frequencies gets shifted.
I don't know WHY you have got yourself all confused -- simple continuity tells you that things stay in step in TIME, hence frequency MUST stay the same.
v = f times wavelength then simply tells you that if v varies, f must remain constant, so wavelength changes if v changes. Hence why, for fixed wavelength (as in an organ), the pitch produced changes if v changes. But that is NOT what we were talking about, but a sound with fixed f travelling into a region with different v.
Doesn't mean that you can't find on the web similar idiots to yourself, who mistakenly believe that since speed varies, so does pitch, whereas the correct result is that frequency is CONSTANT, whatever speeds are encountered during the journey. Organs are different, since what is fixed there is wavelength, not frequency.
A little light quote:
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Post by Progenitor A on Feb 15, 2011 8:46:50 GMT 1
Here's something interesting Carnyx! v = f times wavelength (true!)then simply tells you that if v varies, f must remain constant, ;D so wavelength changes if v changes. ;D There you are, mathematical proof (Another one for the IDIOT SCIENCE thread) And here is one she prepared earlier to show that frequency does change when light moves into a denser meduim! But she can easily live with contradictions The frequency changes when light moves into a gravity well, or moves out of one |
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Post by carnyx on Feb 15, 2011 10:35:54 GMT 1
@nm
Yes, and thank you for reminding me of that interesting case where the frequency of light changes when passing by a mass. Maybe it is because the effective pendulum length has been stretched via quantum relativity so that time has been permanently slowed, or some such STA-stuff. I prefer a change of 'g' myself.
Anyway, to continue the digression for a moment;
The problem with STA's posts is what I would call the Hartrick effect. It starts with a speculation by a poster, that STA apprehends as a threat to her amour-propre,which is bolstered her episotemological knowledge. i.e this need to always maintain a sense of self via the 'knowledge-that' gambit we see in children ... that 'trumping' behaviour via 'I knew you didn't know that which makes you as stupid as I feel all the time so now we are equal and I can feel OK....and is reinforced by the education system .. (aka exploited by teachers as a control mechanism )
It goes like this. A poster proposes a conjecture, as a 'game-starter' in deep terms... for other posters to 'dance' around ( also in deep tems) IF they are so inclined .. and quotes an analogy to help the process along.
The SAT/Hartrick gambit is to seize upon the analogy rather than the point of the proposition and rubbish it via reference to a store of 'knowledge-that' ... In effect wrecking the chance of any 'flight of fancy' which all adults beyond a certain age know is the very stuff of life.
And as mature adults I suppose you can fill in the rest yourself ...
But before we get back to the thread subject proper as opposed to the sidetrack of the sound analogy; which does not actually work for the reason that in a gas, density and gas pressure are effectively in lockstep. But here are a couple of further questions for STA to see if she really can dance, as it were;
1. How do you account for the Hot Chocolate effect, other than via changes of density in the composite medium?
2. And could the Doppler effect also be explained via a relativistic change in density?
Now, back to the thread subject, which starts with the observation that Light waves are generated in areas of very high magnetic and electrostatic strength.
And IF Light/EM waves are reliant on some kind of EM medium, then IF that medium weakens like gravity with distance as a inverse square law, then the frequency of the light ought to drop proportionately as the square of the distance.
Thus, redshift would become a function of distance rather than velocity.
We could start our demolition of this proposal by asking these questions
1. What is the role of permittivity and permeability in the generation and propagation of EM waves? What if they are zero?
2. Are the properties of the permeability and permittivity of free space constant across the universe?
3. If either property changes, will we see a change in EM frequency of traversing waves?
4. In the case of an EM wave passing by a local mass, a local magnet, and a local electrical charge, in each case will we see an effect on;
-apparent direction?
-speed ?
-frequency?
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Post by jean on Feb 15, 2011 12:47:49 GMT 1
The SAT/Hartrick gambit is to seize upon the analogy rather than the point of the proposition and rubbish it via reference to a store of 'knowledge-that' ... In effect wrecking the chance of any 'flight of fancy' which all adults beyond a certain age know is the very stuff of life. The analogy is presumably intended to illuminate the point of the proposition.In order for this to work, there must be points of comparison between the analogy and the proposition. If they cannot be shown to be there, then the analogy fails to illuminate, adds nothing to the discussion and may be disregarded. The sim gambit is then to accuse anyone pointing this out of being over-literal, asserting that the flight of fancy is of value in itself, and must not be looked at too closely. This gambit fails to recognise that any flight of fancy is only as interesting as the quality of the imagination it emanates from, and the degree to which that is prepared to be informed by the understanding of others. |
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Post by carnyx on Feb 15, 2011 13:42:20 GMT 1
A beautiful example of the Hartrick gambit buy Hartrick herself!
First, we read;
Then we see;
.
But, as was stated earlier, it is NEVER disregarded in the STA/Hartrick Gambit, is it! .. which seeks to substitute the analogy for the proposition ... and so is destructive of honest discourse.
And so you must ask why Hartrick is not answering the proposition, but instead proceeds with answering an aside of an aside with another aside .....
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Post by speakertoanimals on Feb 15, 2011 15:39:12 GMT 1
Carnyx is talking utter bollocks (FREQUENCY is constant even though speed changes), and it will remain bollocks no matter how many times he repeats it.
Shame that others have to join in and produce more bollocks:
A gravity well isn't a denser medium. The ENERGY changes if a photon falls in a gravity well, just as a cannonball gains kinetic energy if I stand on a tower and try and drop it on your head. That has nothing to do with what happens to sound waves when they enter denser air.
I think it was more than an analogy in this case, since the very case Carnyx was proposing wasw light changing frequency due to some other effect other than cosmological red-shift. I'd shafted him as regards trying to yuse gravitational red-shift as a possible explanation, so je switched to this totally mistaken denser-medium nonsense instead. The point being, you can't claim that the intial premise is supported by other areas of physics, if you have got it wrong when it comes to the other physics!
And being ABLE to get it wrong also exposes a fatal flaw in reasoning ability -- and if you can't reason correctly for even simple cases (such as sound moving into a different medium), then that should give you a reasonable doubt as to whether the same person is worth listening to when it comes to speculation in a much more difficult area.
But as usual, some don't give a tinkers cuss about the actual PHYSICS, just want to play silly games and claim that everything I have to say is either wrong, incomprehensible, or rude.
I think I'll stick to correct, incomprehensible to the idiots on here at the moment, and as sarcastic and downright rude as I can make it.....................
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Post by carnyx on Feb 15, 2011 15:51:09 GMT 1
STA
Save us the mouth-music, and have a go at answering the bloody physics questions!
But she will not, or cannot, apparently. "No dancin' today" .. or ever, I suppose ...
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Post by abacus9900 on Feb 15, 2011 16:14:43 GMT 1
I think we should go easy on STA because she always has the burden of trying to defend the indefensible! One day she might begin to think for herself and then perhaps things will really get interesting.
BTW, she's not an American is she? She's so rude and cocky (especially for a woman).
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Post by speakertoanimals on Feb 15, 2011 16:27:53 GMT 1
Except you keep ignoring the simple fact that your repeated claim that density effects frequency is bollocks!
The doppler effect (which isn't the cause of the cosmological red-shift BTW) isn't caused by a change in density, just a simple movement of the source.
Back to the mistaken frequency claim. Let's take a simple analogy.
I have a succession of cars going down the motorway, at 60mph, one minute apart. When they reach the entrance to the severn bridge, they pass a baton to a pedestrian, who walks across the bridge at 4mph until they reach the other side, where I collect the batons.
The cars are spaced one minute apart, hence the frequency is one per minute. The wavelength is the distance between cars, which is one mile. ANd unsurprsingly, we find that:
frequency times wavelength = 1 per minute times one mile = 1 mile per minute = 60 miles an hour, the pseed of transmission for cars.
The walkers leave the turnstiles at intervals of one minute, whenever a baton arrives, hence their frequency is also one per minute. They move at 4 mph, hence their spacing in distance is speed divided by frequency, or the distance they walk in one minute, which comes out at 4/60 of a mile.
They arrive at the far end, one oper minute, hence that is the frequency at which I collect the batons.
Hence we see that what is CONSTANT, whatever the velocity, is the frequency. Because even if there is a delay somewhere (everybody goes off for a cup of tea after they have collected their batons), as long as the delay is the same for everyone, the frequency at which I collect the batons is always the frequency at which they were first sent.
If the frequency DID change, then we'd have a pile-up of batons somewhere -- if they arrived at one per minute, but walkers only left once every two seconds, we'd have an ever increasing back-log of waiting walkers! And the frequency can't INCREASE, because then I'd have people trying to leave before their baton has turned up!
Hence the onle sensible answer, for batons as well as for pressure waves, or ripples on water, or whatever, is that the frequency remains the SAME, whatever the transmission speed of the medium.
QED and all that, and let's see what bollocks Carnyx comes up with next to try and justify the indefensible...........................
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Post by carnyx on Feb 15, 2011 16:48:16 GMT 1
STA
Just the usual pile of 'beside the point' stuff, I see.
... try answering the questions set in #38
...or get off the thread.
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Post by jean on Feb 15, 2011 17:24:00 GMT 1
.... The analogy is presumably intended to illuminate the point of the proposition In order for this to work, there must be points of comparison between the analogy and the proposition. If they cannot be shown to be there, then the analogy fails to illuminate, adds nothing to the discussion and may be disregarded. . But, as was stated earlier, it is NEVER disregarded in the STA/Hartrick Gambit, is it! You surely do not mean, carnyx, that you write things for the express purpose of having them disregarded? What you mean, I think, is that you do not want them examined too closely. But they need to be examined, so that their usefulness or otherwise may be understood. After that, they can be disregarded. And so you must ask why Hartrick is not answering the proposition, but instead proceeds with answering an aside of an aside with another aside .... If carnyx chooses to namecheck me in the course of a thread to which I have not contributed, I may choose to respond to his jibe without feeling under any obligation to answer any of the rest of it. |
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Post by speakertoanimals on Feb 15, 2011 18:29:34 GMT 1
Okay, idiot, let's have a go at your daft questions (which you ain't gonna understand given your inability to understand the frequency/density thing):
No, because density doesn't effect frequency.
Bollocks! Light generated in atoms, not necessarily regions of high field strength. SO bollocks right from the start.
Doesn't follow if by 'weakens' you are trying to slip frequency in by the back door. What DO you mean by weaken? Why would you expect the medium to 'weaken' with distance? Distance from what?
Well that's you up the proverbial creek, since cosmological red-shift ISN'T a Doppler shift, and DOES depend on distance, rather than recession speed. The recession speed is only used to give the speed that WOULD give the equivalent red-shift, IF it was producing from a moving source. Which just shows yet again you don't understand the basics of the effect you purport to explain............
'Cept they can't be -- a vacuum is as non-resistant to an electric field as you can get (it's a VACUUM). If you use relative permittivity, then it is permittivity relative to vacuum. One minus this gives susceptibility, which is ZERO for a vacuum, by definition.
As near as damn it. Ain't a lot of stuff out there.
No, because FREQUENCY doesn't change!
Mass distorts path, shifts frequency as it falls, but shifts back as it rises --we have done this already, you can't explain universal red-shift by supposing it is gravity UNLESS we take the earth to be uniquely HIGHER than the rest of the universe.
WHY do you expect women to not be rude and cocky? Whereas seems the supposed chaps on here are cocky, whilst having nothing to be cocky about! A bunch of spineless idiots, judging by this thread!
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Post by carnyx on Feb 15, 2011 19:13:37 GMT 1
@sta
No Hot Chocolate?
But underneath all the pastrami STA agrees!
Oh, just to be absolutely sure of what you are saying, I repeat your words; Red Shift is just a function of distance? In that case, doesn't light frequency somehow drop with distance?
If you really do concur, then we can ask:
is it linear, or does it follow a 1/d^2 function? And how can we we tell, from Earth?
(I'll leave the question of the effect on EM frequencies of changes to permeability and permittivity, to other posters)
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