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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
Craig Markwardt wrote in message ...
There is a nice definition of resonance can be found here by Dr. Vincenz [ref. 1], which I primarily agree with: * Resonance is the process in which oscillations in a system are produced, maintained or enhanced by means of a periodic transfer of energy from another oscillating system, whose frequency is identical to that of the first system. It is important to recognize that there must be some form of forcing or other energy transfer; a vibrating string by itself does not resonate. Also there is a critical or resonant frequency where that energy transfer is at a maximum. Examples of resonances which are not waves: 1. An RLC circuit driven its natural frequency; 2. A playground swing pushed at the natural pendulum frequency; 3. Certain well known orbital configurations. Bodies with orbital radii that have integer ratios, which would normally not exert a large gravitational force on each other, become coupled because of repeated interactions. So obviously not all resonances involve wave phenomena. On the other hand, it is also true that resonance *can* involve waves. Hi Craig The original point was that I responded to Davids claim that resonance was not possible described as a wave phenomena in refernce of course to various people like myself claiming that a wave only classical model can explain observed phenomena. I agree with your point that some phenomena may be not clasified as wave s like a swing but it as a addendum I could still argue that a swing does in a sense still have a maxima where the swing arc is greatest and minima with the fulcrum . And the energy has a oscilation period from each swing extreme as does a wave resonance so it becomes a bit blurred I think the line between a swing resonating to a string and then a medium. But maybe thats not important here. I suppose that the original question was whether photoelectric absorption can be modeled as a resonant process. This is essentially the quantum model of the atom, where the probability of absorption is enhanced for certain frequencies of light, so it's not clear to me what the issue is. I think thats a question for George and David as it is they who claim that resonance cannot involve waves.I say it can . The issue then is why do they insist it cant? --- As to your statement a few weeks ago about the "atom capacitor" model performing better than quantum mechanics and the Grangier experiment: I heartily disagree. In our private correspondence I showed that you made a number of identifiable mistakes (which leaves open the question of as-yet unidentified mistakes); you disgregarded statistical uncertainties (even though I should they were large); and you appeared to ignore even fundamental mathematics. In numerous simulations of thousands of runs I showed that the (simple) "atom capacitor" model does *not* reproduce Grangier's results as you claim. These points I dispute. Statistical uncertainties were a claim you made to say that my results when giving a0 were a statistical fluke I think are unfounded as I redid the numbers experiment about 15 times in different amounts of atoms and all the results were compatible and consistently below a=1 for waves. If anything the onus is on you to show enough or any results that go against mine. The maths accusation stems from early on when Steve C told me that N1 and N2 were the same and that N1+ N2 = N both. I then assumed that N1and2 were the amount of events and equal and calculated accordingly. Later you corrected me and said that N 1 and 2 were the amounts of events where `photons` were recorded. I then corrected my procedure but you still used those early results based on my incorrect assumption that N1 and 2 were the number of events as examples of bad maths. Thats Incorrect and an unfair critism really as it was Steves mistake to have initially said vaguely that N1 and2 were equal and mine inadvertant mistake to assume that meant they had to be equal. When I was first looking into Grangiers experiment it took a bit of deciphering to interpret everyone else sketchy descriptions as to what N1 N2 Nboth represented And finally I dispute your claim that you `Did` the experiment. At no time have you duplicated it correctly and therefore at no time have you been in a position to claim you have performed the experiment I use to show how classical can explain the photoelectric effect. Looking back at our correspondence I find you have given each detector only 1 atom and calculated what happens when 50 per cent of light goes to each detector albeit with a probability formula. That is what Grangier did and that has always been incompatible with my model. To make mine work the detector has to be divided into many atoms and each atom has to be calculated seperately and then corellated together with the other detectors results. At no time did you ever do the experiment in this specified way and always cut corners using averages and statistical probabilities instead of the hard graft needed to duplicate the model correctly If you were to do it as follows: Choose a certain number of atoms per detector . I did 64 Choose a unit value to represent the photon. I used 8. this number is also the same as the 100 per cent full value of each atom Randomly allocate each of those 64 atoms with a set value between 1-100 per cent full. I did 0-8.0 with all different values inbetween like 4.127 or 2.958 etc. Then make two tables with the 64 atoms in each table sort of like as follows 0.162 0.973 1.729 1.978 2.103 2.794 etc for 64 atoms till 7.975 (8 being full) Then below each of the above numbers add for each event exactly 1/128 of 8 units(1 photon and also equivelent to a full atom) So if one photon is released to both detectors at each event then each event you add 0.0625 to each column above. Then just start calculating. An example would be for the first column as follows.. 0.162 0.787 event 1 0.8495event2 0.912 event3 etc ... all the way until the event where when you add 0.0625 and the column number reaches 8 or more. At that event you then mark that to one side as a photon triggered. What you should then get is a huge table of columns with little `*` marks at each event where a column reached or past 8 ( full) sort of like so below with each vertical line of `|` marks denoting a column of numbers denoting each of the 128 atoms filling... detector 1 detector 2 |||||||||| |||||||||* event1 ||||||||||* ||||||||| event2 |||||||||| |||||||||** event 3 ||||||||||* |||||||||* - coincidence event4 ||||||||||** ||||||||| event5 ||||||||||* |||||||||* -coincidence event6 |||||||||| ||||||||| event7 |||||||||| |||||||||* event8 ||||||||||* ||||||||| event9 |||||||||| |||||||||* event10 etc... If you do it exactly as follows and then again with a 1/2 a photon per event( thats 0.03125 per photon pere event ) and then another trial with a 1/4 photon per event and one with 1/8 per event you will find that the 1st trial will give around a=0.8 then the 1/2 photon trial and 1/4 etc will each succesively bring down alpha to about 0.3 for 1/4 to 1/8 photon per event. Just as Grangier observed. And remem ber that Grangier used only about 1/80,000 of a photon per event PER DETECTOR ! in his trials And just to remind you of how completely different your version of my trials were here is sample of yours from back then. Time history N2 N23 ALPHA Trial 1 N3 02001000011100001100201000000010 10 3 0.6400 10100222001010001010010111010020 15 Trial 2 00020003100101000121000000100020 10 6 1.6000 02010002000101000001001120001110 12 Each single line above is your version of one of my whole tables !!!! Here, this is what you did ..02001000011100001100201000000010... ......and that line is supposed to be the same as my table of 64 seperate numbers horizontally of about 64 lines deep per collumn of figures or a table 64 deep by 64 across each number being at least 4 digits .. all calculated seperately and correlated with the other similar table from the other detector. And you claim that this is duplicating my guidelines as you have used some advanced probability formula to DO AWAY with the neccesity for labouriously doing whole tables manualy. Well Craig I`m sorry but your wrong and way off. One of the main reasons for my model is too explicitly show how probability formulas CANNOT duplicate wave atoms and wave only propogation so for you to use them in place of my model is basically defeating the whole purpose and raison d`etre of my experiment. I gaurantee that if you redo the trials exactly as I have specified you will always get a0. And if even you do them over and over again or with 100`s of atoms per detector you will always get well below a=1 and the smaller amount of light used per event will as I have started to illuminate with my own trials will always give you a smaller alpha value. And from a graph of my results I can already see a clear decreasing log curve graph that points towards a=0.18 for a very small photon per event number. But I bet you Craig that you wont do these trials either because as I have found, it takes days for just 1 set of trials or even if you managed to program your pc to do it *correctly* and faster you would not dare to find out that I am right . And thats a challenge . And finally, the "atom capacitor" model disregards the fact that light also has a detectably different wavelengths/frequencies/energies, and instead lumps all radiation into a single "bucket." This is eaxctly the argument David used and I am afraid I dont think it works. It implies that the photoelectric particle theory accounts for an atom being able to detect all frequencies just as easily but in actuall fact all detectors are Very wave specific sensitive with sensitivities centred really around 1 or maybe 2 distinct frequencies with a sharp hump. In other words atoms *cannot* detect all frequencies in photoelectric experiments but are instead only very wavelength specific and a wave only atom can cope with this. I in fact even think now that resonance is how a wave only atom would absorb energy as in experiments on resonance it is the system that responds with an increase in amplitude(just as a wave atom would do ) only when a wavelength of similar frequency is used . THere is a sharp fall off of increased amplitude as the wavelength difference between stystem and inputbecomes more pronounced and this not only is a wave only explanation it is also duplicating that seen in PMT`s where the sensitivity is frequency specific with a sharp falloff on either side. It fits wave theory perfectly! Not only that but Compton scattering experiments apparently I have read have unexplained delays between incidence and reflected light which fits my capacitor theory and cannot be explained by QT. Furthermore I dont know enough about specific experimental results but I wonder if resonance experiments also show systems either with a slight delay in decay for one input or a resonant frequency or amplitude that seems to have a seperate distinct rhythm of beats or frequencies with a regular input then it does without . This would imply that a resonant system when experiencing a driving force input of similar frequency would have some sort of different measurable oscillation or maybe a delayed oscilation. That would be enough to explain the capacitor like ability that I speak of. I need to look more into these sort of experiments tosee if there is some sort of effects similar to the system re- emiting energy in different ways then it is absorbed. Sean |
#62
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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
"sean" wrote in message om... "George Dishman" wrote in message ... "sean" wrote in message om... "George Dishman" wrote in message ... Right, now this is a pattern produced by flexing of the plate or by interference of sound travelling through the plate and being reflected from the boundary. Clearly the medium is essential, no plate, no resonance. Hi George I think whole system is elastic and on very short time scales, parts of the `medium` resonate before parts of the container do. In a violin it is the string then the `air and violin case` . The string also vibrates the air as well as the frame and it almost could be said that the air first begins to vibrate within the frame and it then sets off sympathetic vibrations within the wooden frame which You could say that but you would be wrong. The string does not couple to the air directly because it is thin and cuts through the air instead of moving it. Try bowing an electric guitar with no amp. The string moves the bridge and the soundpost and bass bar transmit the motion to the bulk of the panels. It is the large surface area of the panels that moves the air like a piston. Hi George THats not true George. True, I should have said it couples very poorly rather than "does not couple", sorry. The point is that by far most of the sound is produced by the method I outlined, not direct coupling from string to air. If you were right then a rubber band stretched between your fingers and plucked would be inaudible but both of us know that it is indeed audible . The only way to hear the band is by the air vibrating the air about your ear. So in fact the string resonates the case AND the air and in turn to lesser or greater degrees each sympathetically induces further vibrations in the other. They are coupled and all have a slight effect. If you pluck the string once, the oscillation will die away slowly over a large number of cycles. The energy lost per cycle is small so the other effects can have only a small influence on the motion of the string. If you stopped reading books and watching the world around you you would understand physics better Go get yourself an empty bottle ;-) http://www.phys.unsw.edu.au/~jw/violintro.html#bridge then feeds back into the air and string but mostly the energy from all 3 dissapates to the concert hall and in turn to the structure , which then disappates some back to the air and some to the outside or foundations etc... In different situations I think diofferent parts of the system resonate firstbut remember this started out as my response to davids claim that a medium could not exhibit resonance! The sad thing is that even if you agree with me that he is wrong on that point I don't. There you go George you say just for the sake of it that you dont agree with me yet later on you admit that a medium like air IS part of a resonating system and I supply you with your own quotes to back this up. So you contradict yourself when you say that you Do agree with him that a medium cannot resonate within a system. Make up your mind, can a medium within a system be said to exhibit resonance? The system can exhibit resonance, the medium can be part of the system, but I wouldn't say the medium was exhibiting the resonance. Have you got that empty bottle yet? Good, now blow over the top and see if you can get a note. The note is determined by the shape of the bottle. Now try it without the bottle. The air is still there but do you get a nice clean note? Bexcause if you say that NO a medium in a system cannot be said to exhibit resonace then you immediately contradict yourself with the quotes later reproduced in this post . One being that if one removes the air or medium from a resonating system then the remaining part of the system experiences an increase in amplituide or stored energy or Q or whatever particular term you wish to call it . And the Q could only increase in the remaining part of the system if it had only been present in the air/medium before it had been removed. One classic resonant system is a mass, spring and damper. The mass bounces on the spring and the oscillation dies away exponentially as energy is turned into heat in the damper. Take away the damper and the spring bounces for longer. I believe the letter "Q" is used because it is a "Quality Factor", so reduce the damping and you increase the Q. Removing the air means that sound is no longer produced so energy is not lost that way. There are still losses in the string and wood but Q will increase due to the reduced loss. I think actually George it is you who must learn what resonance is as you seem to constantly offer opposing views of what it is. I am trying to show examples that highlight the essential features of resonance. With the bottle example, if you remove either the bottle or the air you won't get the resonance. Fill the bottle with helium and the frequency will change. Clearly the medium plays a part but without the bottle there is no resonance. he will still continue to post that a medium cannot resonate. He doesnt seem to listen and learn. I have said I don't agree with you several times. I have also given you several examples of resonance in systems without waves. If you listen and think about those, you may learn what the word "resonance" means. How about we stick to this short definition: Resonance is `when a vibrating system responds in amplitude with an alternate driving force where the two frequencies are similar. ` Fine. The key phrase there is "vibrating system". First you have a system that vibrates, then you drive it at its natural frequency. So for instance, if two vibrating sources in an open water tank What is the natural frequency of water in an open tank? Put in just a single source running at that frequency and you would have resonance. However, the resonant frequency in a tank of water is determined by the dimensions, typically when the wavelength on the water is comparable to the size of the tank. Put a vibration source in the middle of the Atlantic and you just get ripples moving away from it and dying out before they can hit a continent. You get travelling waves, not resonance. as I described earlier set up nodes of maxima patterns. (which are what you call interfernce yet still can be said to be stationary maxima or ` a vibrating system` or stored energy)If a third vibrating source is added to create a triangle of 3 sources then the maxima pattern changes and one would get a different pattern of nodes instead of bands and the central part of the vibrating medium now or central maxima has increased amplitude. Now that is a definition of resonance according to the textbook definition. I have a vibrating system,the water in between the two sources that has staionary maxima between the two sources .And then I add a new driving force of similar wavelength and the maxima, still stationary, now have their amplitude increased. That is all within the textbook definition. I think you are being dogmatic by saying a medium cannot` resonate `. Yet there is no restriction I have read in textbook definitions of resonance that say only solid objects like wood or metal can resonate. Absolutely. Let me give you another example that you might find 'contradictory'. The Sun is just a ball of gas, pure medium, yet it exhibits resonance! The subject of helio-siesmology is greatly concerned with resonance. I talk below of "containment" and in this case it is the boundary between regions of different density that provides the container. The only prerequisite is that the system has to be vibrating, and the word system does not exclude a medium like air or water You are being dogmatic in saying that only a vibrating string contained at either end that has additional energy input and has its amplitude increased can be said to resonate and yet, When water in a vibrating container has the vibrations increased in amplitude those maxima within the water increase. That is to me a vibrating system that responds with an increased amplitude to additional driving force. Of course, I agree, but there you have a container. All I am saying is that the thing you are considering has to have a natural vibration. Air in a container does, air without the container doesn't. The only difference I can see is that the strings `resonance` has a longer sustain then the water in the tank. For instance if I vibrate the tank the nodes appear and when I stop the vibrations they will disappear very rapidly probably within a second They dissapear progressively as the end of the ripples from the source moves over the surface at the speed of the waves in the medium. whereas the string will sustain for a few seconds although it must be said that the water when the outside vibration source stops probably still has a sustain of those nodes its just that they become too small to see with our eyes. And if you consider a string that is vibrating and then continuously plucked that string continues exhibiting resonance. But surely when a container of water is continuosuly vibrated , each shake is essentially the same as each pluck of the string in that it is a series of additional driving forces and the result is a continously vibrating container of water . That water is exhibiting resonance becuase the waves contained within the system have their amplitudes continuosly added to by additional driving forces of similar wavelength which in turn sustains the amplitude of the stationary nodes. And if a different frequency of vibrations was introduced those particular nodes would disapeear as they did not have the defining "additional driving force of similar wavelength " That's right, but again you are talking of "a container of water" and "the waves contained within the system". The containment is an esential part of the system. We talked about this befo .... My argument would be that in an infinite universe as long as the density is homogenous in all parts of this infinite universe the density at any one point is constant or average. OK. In fact any change in homogeneity could act as a boundary. The changes in density in the Sun are an example of what I meant. Therefore one important prerequisite for a resonating infinite medium is met. Secondly I thought about it and actually a medium can resonateand standing nodes of maxima CAN occur in our observable world in water or etc in open uncontained systems . This can be done simply by having 2 identical energy sources creating waves and at the point or in the region between the two sources there are standing waves produced | | | A | | | B | | | Above A and B are vibrating sources in an open uncontained medium and the vertical lines denote maxima where overlapping waves create standing waves . This is _interference_, not _resonance_! For resonance you must be able to store the energy _after_ the driving force has gone. Please try to understand what the word means. The interference pattern exists only as long as the sources remain active. That is such a load of nonsense George. That is physically impossible for those maxima to instantly disapear and if you believe that then you believe in magic. Those maxima or nodes will disapear but within a short time frame as the energy disapates to the surrounding air, They disappear at the speed of the waves in the medium. just as a string stops vibrating over a slightly longer but still short time frame of maybe a second or two . I bet if one took high speed photography of my above illustration one could actually see the water maxima decay over a few hundreths of a second maybe even a tenth of a second. Do you really seriuosly believe that the maxima disapear instantaneously with no decay? No, nor did I suggest they would. Remember my diagram: Take a very long taut wire and send two bursts of a wave of the same frequency travelling in opposite directions from the ends towards the cent --\/\/\/\/\/\/\----------------------/\/\/\/\/\/\/\/--- --- --- When they meet in the middle, they will create a standing wave pattern of while they overlap (it's twice the height but I can't show that) and pass through each other -----------------\/\/\/\/\/\/\------------------------ after that they just separate though --\/\/\/\/\/\/\----------------------/\/\/\/\/\/\/\/--- --- --- The interference pattern in the middle is a wave phenomenon but it is not resonance. You have to imagine the two bursts moving in the direction of the arrows. When they meet there is a small region of interference (shown with '|') that grows and then shrinks. -----------\/\/\/\/\/\/\----/\/\/\/\/\/\/\/------------ ------------\/\/\/\/\/\/\--/\/\/\/\/\/\/\/------------- -------------\/\/\/\/\/\/\/\/\/\/\/\/\/\/-------------- --------------\/\/\/\/\/\||/\/\/\/\/\/\/--------------- ---------------\/\/\/\/\||||/\/\/\/\/\/---------------- ----------------\/\/\/\||||||/\/\/\/\/----------------- -----------------\/\/\||||||||/\/\/\/------------------ ------------------\/\||||||||||/\/\/------------------- -------------------\||||||||||||/\/-------------------- -------------------/|||||||||||||/--------------------- ------------------/\/||||||||||||\--------------------- -----------------/\/\/||||||||||\/\-------------------- ----------------/\/\/\/||||||||\/\/\------------------- ---------------/\/\/\/\/||||||\/\/\/\------------------ --------------/\/\/\/\/\/||||\/\/\/\/\----------------- -------------/\/\/\/\/\/\/||\/\/\/\/\/\---------------- ------------/\/\/\/\/\/\/\|\/\/\/\/\/\/\--------------- -----------/\/\/\/\/\/\/\/--\/\/\/\/\/\/\-------------- ----------/\/\/\/\/\/\/\/----\/\/\/\/\/\/\------------- ---------/\/\/\/\/\/\/\/------\/\/\/\/\/\/\------------ Show me the experimental proof that a system as I propose defies conservation of energy and actually some energy according to you `disapears instantaneously` from our universe. This is seen in water tanks etc experiments and shows how classical waves can resonate in an open system and create maxima (in this case bands rather than nodes) So theoretically in a open infinite universe the aethger medium could resonate and nodes of maxima would be possible. Nodes and antinodes occur due to interference. Yes,Nodes and antinodes are seen in interference patterns . But if you read a textbook definition they are also said to occur in standing waves. And is not a string vibrating in essence a standing wave? A vibrating string is where the wave energy travelling down the string is reflected back at the boundary, the guitar bridge, and is superimposed on the incident wave creating a staionary node in the midle of the string with the standing wave as having the same length as the length of the confined string. Exactly, and the point I am trying to get across is that something to reflect the energy and keep it contained is the key to turning travelling waves into a resonant system. And finally how to account for the sources A and B in a infinite classical universe? If the universe is infinite and of homogenous density aether, wave energy of all wavelengths travels across any point from all directions at any time . So at any point in this universe a situation that duplicates the above illustration can occur where the overlapping wavefronts cancel out as in a closed system and create maxima. As the similar wavefronts come from all directions and not just the two as in the above illustration instead of bands of maxima one gets nodes. In otther words this is how a wave only atom can be explained in a infinite universe using examples of resonating open systems of mediums already observed in our world. The medium in which these nodes appear is not one object but can consist of air, gas, water sand etc. It isnt then the cavity that resonates but the medium within the cavity that resonates No, it is the combination. That's why I emphasise it is a system not just the medium. For example your plate would not resonate if ^^^^^^^^^^^^^^^^^^^ it were infinite in size, it is the boundaries that create the resonance. Here you do admit that a medium can resonate I suggest you read it more carefully again, I said exactly the opposite. You speak in riddles and contradictions. What is the opposite of me saying a medium can resonate? Answer: You say It CANT resonate... I assume thats what you mean by "the opposite". I didn't use the words "the opposite". Then you suggest that a medium CAN resonate, within a system, by saying "no its a combination". Ah,! a contradiction . No, not a contradiction, that is the whole point of my saying it that way! You have to ask yourself what is the difference between "the combination can resonate" and "the medium on its own does not resonate". How can both be true? You just said a medium cant resonate and then you suggest it can . Maybe what you mean to say is that a medium can resonate within a contained system? Is that what you mean by " no its the combination" ? What I mean is that the medium can be part of a system that resonates. It is "the system" that is resonating, not just the medium. You can drive to work in a car but you can't drive to work on a piston even though pistons are an essential part of the car. You get resonance from a bottle of air but you don't get resonance from the air on its own even though the air is an essential part of the bottle/air system. Yes but hopefullly I have shown that in an infinite open system there is always wave energy arriving and that in an open system resonance can occur with maxima. Resonance does not mean maxima and you have not deemonstrated how energy can be stored on a small fixed region using only an infinite and homogenous medium. Where did I ever say that Resonance is just maxima? You said "I have shown ... that in an open system resonance can occur with maxima." when in fact all you had shown was that maxima could occur. You phrasing suggests you were using "with maxima" to imply they were the means by which you had demonstrated resonance rather than "with" meaning "in addition to". That doesnt even make sense. Its kind of like me describing an orange and you saying "NO ,you are wromg an orange isnt just orange".. Resonance does not just mean maxima but maxima can be seen in a resonating system. Absolutely correct, that is what I said, but you had only shown you could get maxima (by interference) and then claimed you had shown resonance. The central point of a vibrating string is a maxima where the displacement of string mass is greatest. And in a pendulum the maximum displacement and therefore stored energy is in the end weight of the pendulum. Is that not a node or maxima in both central point of a guitar string and end weight of a pendulum? Regarding whether or not a infinite medium can store energy in a fixed point like a node how about this: Two vibrating sources of Try showing it with one source. energy A and B are infinitely far apart and have been vibrating at the same frequency for infinity and their two wavefronts approach and overlap as follows A | | | | | | | | | | | | | | | | | | | | | | B This duplicates the earlier diagram where the two sources are a finite distance apart and as long as the two sources have been vibrating infinitely then when they do reach and overlap a series of standing waves or maxima nodes occur exactly as in the finite example. And these nodes will remain in the same spot and retain the same amplitude as long as A and B have not moved. And finally viewed up close at one maxima the maxima can be said to be duplicating in all respects the same conditions and appearances as a similar maxima within a finite container where the additinal driving force on that container is exerted continuosly and is said to be a resonating system. "Resonance does not just mean maxima" In a `violin in air` situation the air within the frame also resonates and this amplifies and feeds back into the whole system so it is technically the string ,bridge, frame and air within the cavity that resonate. No, technically there are several independent resonators that are coupled mechanically. How petty. Thats just another way of phrasing my description. You said "technically" and if you want to get into the technical details we need to extend this to include coupling coefficients and stuff. It gets a lot harder and I don't want to get into that. Thats like me saying..."putting a plug into the drain will prevent the bath from emptying".... and then you saying.." No, technically a stopcap is coupled manually with the outflow port of a water system to prevent leakage" Suspend two pendulums of slightly different length on a common mounting. Start one swinging and after a while the other will swing. Eventually the first will stop and then the whole thing reverses. Each swings at its own frequency. Glue the two weights together and the combination swings at an intermediate rate. There is a significant (technical) difference between saying the string vibrates and excites other resonances and saying they all resonate as a single system. Yes the string I am sure would still vibrate in a vacuum. And if the body were also removed yes the string itself would also vibrate . So the conclusion is that a system of one or many parts can resonate . Right, but remove the bridge and it wont. The string must be held in tension, it must be fairly free to move over most of its length but has to be clamped at the ends to reflect the wave. All those are required for it to contain the energy of the vibration. Of course this is true. What I was suggesting that if the string were clamped or held rigid but the body were removed so as to remove vibrations from a closed or semi closed wooden frame from the system. Sort of like stretching a rubber band between your fingers.Effectively your fingers are not part of the resonating system except that they contain the rubber band. But that is exactly what makes them a part of the resonating system. The fact is, remove the clamps the string would flop down to the floor of the room or whatever and it would be impossible to input a energy to the string in the first place and I never suggested that a medium or object could resonate without any input energy. No, but you are suggesting the rubber band will resonate without the fingers when you say an _open_ medium can resonate. A medium /object will also only resonate (or vibrate and give stationary nodes) if there is energy input and the medium/object density remains the same . For instance a bell will resonate even if is floating in air by being thrown as long as the bells density remains the same and if it were possible to continually strike it with the same input driving force while mid air its resonance would not decay. Absolutely, and it would also resonate in a vacuum if excited by a pure sine wave from a nearby electromagnet. By adjusting the source frequency for maximum amplitude, you can find the resonant frequency of the bell. In an infinite universe the density can remain the same and the energy input can remain constant as I have explained earlier and therefore a uncontained medium like aether could exhibit resonance as nodes of energy Nope, to get nodes you _must_ have something to reflect the waves back so they interfere with themselves. You have shown you can get interference in an unbounded medium which was never in dispute. You still seem not to be listening to what the word "resonance" means. All the arguments you have oferred are applicable to interference, not resonance. Forget about waves for a moment and consider how a mass and spring system or a pendulum can be resonant. I have already answered this but I will again but if you dont mind I will stick to my one textbook definition of resonance as yours seems to change depending on the point you are arguing... `Resonance is where the amplitude of a vibrating system responds to an additional driving force of similar frequency.` Hence... a medium in this case is constrained That's the point Sean (or is it Jay BTW?), to make a "vibrating system" you have to _constrain_ the medium. and vibrating and contains energy stored as maxima minima where the reflected waves of the enrgy in the medium overlap and superimpose. Or.. a string constrained is vibrating and the energy is stored as maxima and minima in the string where the reflected waves of the energy in the string overlap and superimpose. Next,... An additional driving force of similar frequency is exerted on the medium and the amplitude/energy of the maxima and minima is increased or sustained Or,...An additional driving force of similar frequency is exerted on the string and the amplitude/energy of the maxima and minima is increased or sustained In experiment each continued shake of the container sustains the resonance of the system of the container and the medium and in the case of the string each additional pluck of the string sustains the resonance of system being the string and the clamped frame that holds it Your second point doesnt make sense in grammatical terms. What do you mean by "..but nothing else.." in the sentence above? I meant with nothing to refect the waves back so they can be contained in one area thus storing energy. George That means You said. quote ...."If you said you can get resonance with waves in a medium but nothing else then you are also wrong."..unquote. That is correct, you need something to constrain the medium. Even a change of density can be enough. In response to me saying..."In other words David is completely wrong in saying that a single particle or object vibrating is the only manifestation of resonance."... That is correct. A spring/mass system is resonant but a mass on its own isn't, and nor would a massless spring be. Note that my line you responded to (obliquely and with intent to obfuscate) actually wasnt saying that a medium uncontained could resonate but that David was wrong to assume that a medium vibrating in a container was not exhibiting resonance. If that's what you meant then I would not have responded but it is not what the post I saw said, and you have continued over the last several posts to argue that open, unconstrained medium can resonate. Yet you knew that if you responded directly to my point you couldnt say that David was right in saying that a medium in a system wasnt resonating because even above you admit that a system with a medium and a container can be said to resonate. So to avoid the embarrasment of having to admit David is wrong to think a medium in a system cannot resonate you instead fabricate the untruth that I was always insisting that only a medium without a container could resonate . Thats absolutely untrue as initially my point to David was quite clearly that a medium in a container could be said to resonate. And I know what your response will be to this will be . You will say something contradictory that implicitly agrees with me yet tries to make it seem you dont agree as in one of your below quotes previously.. No, I'll just let you say it for me ..... GD.. "No, it is the combination. That's why I emphasise it is a system not just the medium. "... (Sean..goodness that sounds like you admit a medium constrained can resonate) GD..""If you said you can get resonance with waves in a medium but nothing else then you are also wrong."... (Sean ..there you go again, the implication in that statement is that with nothing else, ie no container , there can be no resonace which implies that with a container the medium and the system can resonate) I think all of the above are very clear in the distinction they are drawing. GD.."Of course no air, no resonance in this case, but for the string, bridge and fret resonance, putting the violin in a vacuum chamber would actually increase the Q of the resonance since a large part of the power lost from the string goes into moving the air via the mechanical linkages to make the sound we hear."... ( Sean.. there you go again suggesting that in a vacuum without the air to `absorb` or hold some of the resonant energy the energy amplitude has to increase in the remaining parts of the system. Implicit in your statement is then the assumption that with air in the system the energy stored is less in the other parts of the system and therefore the only conclusion is that if the air stores some of the energy and it is part of the resonating system then a medium can be part of a resonating system which according to David is not possible) The energy is mainly stored in the string and some is transferred to the flexions of the body. There is only energy stored in the air in the form of the Helmholz resonance (as in blowing over the bottle) but the more important aspect is that the air acts principally like the damper in the mass/spring system. It removes energy from the 'vibrating system' of your definition and converts it as the sound we hear. George |
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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
Dear George Dishman:
"George Dishman" wrote in message ... (formerly)" dlzc1.cox@net wrote in message news:9o87b.47469$Qy4.20923@fed1read05... Dear George Dishman: "George Dishman" wrote in message ... "Aleksandr Timofeev" wrote in message om... ... If we shall eliminate transients viewing, the source of oscillations is indispensable for observation of oscillations in resonant system. If a source of oscillations, which one has frequency close to frequency of resonant system, misses, the oscillations in resonant system CAN NOT BE WATCHED. Ah you mean a signal source, not a power source. I thought you meant like the power supply needed for the RC oscillator. Yes, the phenomenon of resonance is an interaction between a signal source and a system capable of oscillation, but that resonant system can itself be passive. George, would you say that photons that couple the source to the system in only one direction provide sufficient "interaction" for an RC based oscillator? Sorry David, I'm not sure what you mean. By an RC oscillator I mean a discrete circuit built from electrical components. Photons would let you see the PCB and the components but that's all. It would appear that Aleksandr is attempting to liken the behaviour of an RC circuit to the conduction-band behaviour of electrons in the photoelectric effect. Then he wants the source (namely the photons) to create resonance in the "RC circuit". If you put a diode between the power supply and the RC circuit, can you still get resonant behaviour? The supply would be DC so if the positive goes to the anode the circuit would work as usual but if it goes to the cathode there would be no power to the circuit and it just wouldn't work. I think you may be referring back to an earlier part of the thread that I missed. I'm trying to head off a few partial questions/answers and cut to the chase. Aleksandr tends to not get to the point sometimes... The source in the exmaple you discuss has inductance (no matter how distant it might be) that the RC circuit can "store momentum" in. If the communication from the source is one way, like a diode, then communication can only be one way. Resonant behaviour cannot be elicited in a pure RC circuit with only a diode to couple. Can it? David A. Smith |
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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
(formerly)" dlzc1.cox@net wrote in message news:JKt7b.47635$Qy4.32727@fed1read05... Dear George Dishman: "George Dishman" wrote in message ... (formerly)" dlzc1.cox@net wrote in message news:9o87b.47469$Qy4.20923@fed1read05... George, would you say that photons that couple the source to the system in only one direction provide sufficient "interaction" for an RC based oscillator? Sorry David, I'm not sure what you mean. By an RC oscillator I mean a discrete circuit built from electrical components. Photons would let you see the PCB and the components but that's all. It would appear that Aleksandr is attempting to liken the behaviour of an RC circuit to the conduction-band behaviour of electrons in the photoelectric effect. Then he wants the source (namely the photons) to create resonance in the "RC circuit". OK, in that case the answer is that a single RC circuit does not provide enough phase to oscillate. It takes at least three connected in series, but I am surprised as I think Aleksandr knows that. If you put a diode between the power supply and the RC circuit, can you still get resonant behaviour? The supply would be DC so if the positive goes to the anode the circuit would work as usual but if it goes to the cathode there would be no power to the circuit and it just wouldn't work. I think you may be referring back to an earlier part of the thread that I missed. I'm trying to head off a few partial questions/answers and cut to the chase. Aleksandr tends to not get to the point sometimes... The source in the exmaple you discuss has inductance (no matter how distant it might be) that the RC circuit can "store momentum" in. In that case it is not an RC circuit but an LRC. That can oscillate but note that the energy can be entirely in the C and half a cycle later it will be entirely in the L. The R produces the loss per cycle and needs to be small or the system will be over-damped. The problem here is how do you set this up so that the existence of momentum in the source provides the stimulus for the conduction band, and also once that transfer is complete, then have the momentum now in the conduction band produce the opposite-sense stimulus back to the source, all within the period of a single cycle. How distant the source is would be very important. If the communication from the source is one way, like a diode, then communication can only be one way. Resonant behaviour cannot be elicited in a pure RC circuit with only a diode to couple. Can it? Resonance cannot occur in a pure RC period but it will occur in an LCR if the losses aren't too great. The effect of a diode in the driving signal as you describe (not the power supply) is simply to create an impulsive force like giving a swing a brief push on the way down rather than a sine wave force over the whole swing. Certainly that would exhibit resonance. George |
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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
\(formerly\)" dlzc1.cox@net wrote in message news:JKt7b.47635$Qy4.32727@fed1read05...
[snip] I think you may be referring back to an earlier part of the thread that I missed. http://www.google.com/groups?selm=10...s.uk.clara.net I'm trying to head off a few partial questions/answers and cut to the chase. Aleksandr tends to not get to the point sometimes... The source in the exmaple you discuss has inductance (no matter how distant it might be) that the RC circuit can "store momentum" in. If the communication from the source is one way, like a diode, then communication can only be one way. Resonant behaviour cannot be elicited in a pure RC circuit with only a diode to couple. Can it? OSCILLATORS Phase-Shift Oscillator http://home.earthlink.net/~doncox/wec/Oscillators.html http://www.google.com/groups?selm=10...s.uk.clara.net Aleksandr |
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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
Dear Aleksandr Timofeev:
"Aleksandr Timofeev" wrote in message om... \(formerly\)" dlzc1.cox@net wrote in message news:JKt7b.47635$Qy4.32727@fed1read05... [snip] I think you may be referring back to an earlier part of the thread that I missed. http://www.google.com/groups?selm=10...s.uk.clara.net I'm trying to head off a few partial questions/answers and cut to the chase. Aleksandr tends to not get to the point sometimes... The source in the exmaple you discuss has inductance (no matter how distant it might be) that the RC circuit can "store momentum" in. If the communication from the source is one way, like a diode, then communication can only be one way. Resonant behaviour cannot be elicited in a pure RC circuit with only a diode to couple. Can it? OSCILLATORS Phase-Shift Oscillator http://home.earthlink.net/~doncox/wec/Oscillators.html http://www.google.com/groups?selm=10...s.uk.clara.net Too bad the source (transistor) and receiver (RC network) are directly coupled, such that they do communicate. Even a diode (which would be silly anyway) added to the base junction would have little effect. Isn't this circuit "locked in" on a single operating "resonant" frequency? Hardly the behaviour of the real thing... So are you claiming that the photoelectric effect is explained by a wavelet being absorbed by a section of a conductor, and even with losses (the threshold presumably) somewhere else (perhaps) the electron is emitted? Such delays are not seen in the real effect. Electrons are noted arriving "on time" for release of electron upon arrival of photon. How do the local conduction-carrier-centers know how many times the arrival information has been passed down? Electrons are detected when photon intensity is reduced to the point where only one is arriving at a time. Must be quite a signalling system. Doesn't even care what the structure of the base material is. Decreasing the resistance by heating creates just a lower threshold (your example, thermionic emission). I believe this would alter your example "phase-shift oscillator" in the wrong direction, increasing the oscillating frequency. As if requring more energy in the photon, and not less as seen. A valiant effort Alexsandr. David A. Smith |
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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
(formerly)" dlzc1.cox@net wrote in message newsrG7b.48431$Qy4.11136@fed1read05... Dear Aleksandr Timofeev: "Aleksandr Timofeev" wrote in message om... \(formerly\)" dlzc1.cox@net wrote in message news:JKt7b.47635$Qy4.32727@fed1read05... [snip] I think you may be referring back to an earlier part of the thread that I missed. http://www.google.com/groups?selm=10...s.uk.clara.net I'm trying to head off a few partial questions/answers and cut to the chase. Aleksandr tends to not get to the point sometimes... The source in the exmaple you discuss has inductance (no matter how distant it might be) that the RC circuit can "store momentum" in. If the communication from the source is one way, like a diode, then communication can only be one way. Resonant behaviour cannot be elicited in a pure RC circuit with only a diode to couple. Can it? OSCILLATORS Phase-Shift Oscillator http://home.earthlink.net/~doncox/wec/Oscillators.html http://www.google.com/groups?selm=10...s.uk.clara.net Too bad the source (transistor) and receiver (RC network) are directly coupled, such that they do communicate. There is no source shown in this circuit. The whole thing is the oscillator or "vibrating system" in the definition Sean gave. There are a number of ways to add a source such as injecting a current into the base or emitter via a high value resistor (direct) or by varying the value of the first C in the chain (parametric). Even a diode (which would be silly anyway) added to the base junction would have little effect. You could add it in series with the source resistor but you are right, it would have little effect unless the resonant frequency were a harmonic of the source frequency. BTW, what I called the power source is the 10V battery on this diagram so you can understand why I wondered why you asked about putting a diode in series with it. Isn't this circuit "locked in" on a single operating "resonant" frequency? Hardly the behaviour of the real thing... Reduce the amplifier gain, the ratio of Rc to the transistor's internal emitter resistance (not Re!), until the circuit just fails to oscillate then apply the source signal. I'll leave you to debate how this relates to the photoelectric effect with Aleksandr. George |
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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
"George Dishman" wrote in message ...
The energy is mainly stored in the string and some is transferred to the flexions of the body. There is only energy stored in the air in the form of the Helmholz resonance (as in blowing over the bottle) but the more important aspect is that the air acts principally like the damper in the mass/spring system. It removes energy from the 'vibrating system' of your definition and converts it as the sound we hear. George Hi George THanks for your informative reply and if you dont mind I will still argue my case I will post this message as a response to all your valid points made and save google space by deleting both of our arguments. I have quoted from your arguments and hopefully anyone else reading will go back to your post to see the relevent context rather than me reposting the whole argument. George Here are a few quotes of yours ......... That is correct, you need something to constrain the medium. Even a change of density can be enough. That is correct. A spring/mass system is resonant but a mass on its own isn't, and nor would a massless spring be. Clearly the medium plays a part but without the bottle there is no resonance. What I mean is that the medium can be part of a system that resonates. It is "the system" that is resonating, not just the medium. The Sun is just a ball of gas, pure medium, yet it exhibits resonance! The subject of helio-siesmology is greatly concerned with resonance. I talk below of "containment" and in this case it is the boundary between regions of different density that provides the container........ In other words here you say that a resonating system that is only a medium, "pure medium" as you say in your sun example can, as long as it was contained , exhibit resonance! So Davids claim that a medium cannot exhibit resonance is incorrect unless he were to have added the proviso that it had to be contained to exhibit resonance. And he didnt offer this option on this thread that a medium could exhibit resonance if it were contained but rather was trying to insinuate that a medium in any circumstance,.. contained or uncontained,.. could not exhibit resonance. Therefore he is wrong to insinuate this UNLESS he is willing to admit that yes a medium contained , CAN exhibit resonance That was the reason why I interjected and will continue to do so whenever he claims that only a particle can exhibit resonance. Because he is wrong and the fact is that a medium like gas or air CAN exhibit resonance as long as it conforms to.. "George Dishmans rules of containment" And this leads me to the next part of my argument That in an infinite universe wave only atoms in medium *can* exhibit resonance. You say that an infinite homogenous universe cannot exhibit resonance because the medium called aether or vacuum is uncontained. Yet if the medium were not homogenous but as observed having different densities would it not be true that the boundaries between these different densities could supply the requisite George Dishman boundary conditions to allow a medium to resonate? And the observed universe does indeed have different densities from stars to interstellar mediums to intergalactic mediums. And a medium within a resonating system like a sun or star is said to exhibit resonance according to the George Dishman rules of resonance And a resonating system is said to contain nodes or maxima and although according to the GD rules these nodes do not constitute resonance themselvesthey are none the less observed within resonating systems. And atoms, by classical wave only theorists like myself, are essentially theoretically referred to as nodes within a resonating system (that is a medium exhibiting resonance like the sun withy boundary conditions) And as the universe has observed boudary conditions by way of observed different observed interstellarmedium densities then it can be said that according to the George Dishman rules of resonance the universe as it contains OBSERVED boundaries and yet is only a medium then therefore one, can according to GD rules, say that nodes of maxima occur within this resonating system of a universe medium that is contained (or more correctly maybe ...subcontained) And therefore according to George Dishman rules if a wave only theorist says that an atom is only a node within a resonating contained medium then George HIMSELF has confirmed this to be possible. And just a seperate question which you may be able to supply the answer. Why does a TV picture on a tube TV reduce slightly before disappearing when the OFF button is pressed? It seems that the whole image reduces in entirety and not just the edges creeping in. This happens within less than a second after the off button is pressed Sean |
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Gravitation and Maxwell's Electrodynamics, BOUNDARY CONDITIONS
"sean" wrote in message om... Hi George THanks for your informative reply and if you dont mind I will still argue my case I will post this message as a response to all your valid points made and save google space by deleting both of our arguments. I have quoted from your arguments and hopefully anyone else reading will go back to your post to see the relevent context rather than me reposting the whole argument. George Here are a few quotes of yours ......... That is correct, you need something to constrain the medium. Even a change of density can be enough. That is correct. A spring/mass system is resonant but a mass on its own isn't, and nor would a massless spring be. Clearly the medium plays a part but without the bottle there is no resonance. What I mean is that the medium can be part of a system that resonates. It is "the system" that is resonating, not just the medium. The Sun is just a ball of gas, pure medium, yet it exhibits resonance! The subject of helio-siesmology is greatly concerned with resonance. I talk below of "containment" and in this case it is the boundary between regions of different density that provides the container........ In other words here you say that a resonating system that is only a medium, "pure medium" as you say in your sun example can, as long as it was contained , exhibit resonance! I think your getting the idea :-) So Davids claim that a medium cannot exhibit resonance is incorrect unless he were to have added the proviso that it had to be contained to exhibit resonance. And he didnt offer this option on this thread that a medium could exhibit resonance if it were contained but rather was trying to insinuate that a medium in any circumstance,.. contained or uncontained,.. could not exhibit resonance. Therefore he is wrong to insinuate this UNLESS he is willing to admit that yes a medium contained , CAN exhibit resonance You can argue that with David. That was the reason why I interjected and will continue to do so whenever he claims that only a particle can exhibit resonance. Because he is wrong and the fact is that a medium like gas or air CAN exhibit resonance as long as it conforms to.. "George Dishmans rules of containment" And this leads me to the next part of my argument That in an infinite universe wave only atoms in medium *can* exhibit resonance. Any system that can oscillate, or 'ring', can resonate if driven by a signal at the same frequency as its own natural oscialltion. The most common use is probably in old radio receivers where a "tuned circuit" was used to select the wanted signal. The only other requirement is that losses are not too hig so that there is still some energy left after each cycle. I mentioned that in respect of the "Q" factor of electrical circuits on a number of ocassions. You say that an infinite homogenous universe cannot exhibit resonance because the medium called aether or vacuum is uncontained. Yet if the medium were not homogenous but as observed having different densities would it not be true that the boundaries between these different densities could supply the requisite George Dishman boundary conditions to allow a medium to resonate? Yes, you have got it :-) And the observed universe does indeed have different densities from stars to interstellar mediums to intergalactic mediums. We are now measuring the ringing of other stars, but losses in the interstellar medium would probably prevent resonance on larger scales. Still there is another article in the group on "sound" travelling through interstellar gas with a period of millions of years and if the nebula has an abrupt boundary even that could resonate when the sound is reflected back. And a medium within a resonating system like a sun or star is said to exhibit resonance according to the George Dishman rules of resonance No, the system is said to exhibit resonance, the medium is not. That is the point I was making about terminology. Your understanding of the physics is now right but your use of the word is unconventional and hence confusing. And a resonating system is said to contain nodes or maxima and although according to the GD rules these nodes do not constitute resonance themselvesthey are none the less observed within resonating systems. Right, nodes and antinodes also occur in interference so you can have nodes without resonance. A mass and spring system can also exhibit resonance without any waves being involved. And atoms, by classical wave only theorists like myself, are essentially theoretically referred to as nodes within a resonating system (that is a medium exhibiting resonance like the sun withy boundary conditions) I would have expected them to be antinodes but QM is too far in my past to remember clearly. And as the universe has observed boudary conditions by way of observed different observed interstellarmedium densities then it can be said that according to the George Dishman rules of resonance the universe as it contains OBSERVED boundaries and yet is only a medium then therefore one, can according to GD rules, say that nodes of maxima occur within this resonating system of a universe medium that is contained (or more correctly maybe ...subcontained) I think you got over-enthusiastic when writing that. I think I follow but you are jumping ahead. If you are talking about pressure waves in interstellar gas, you need to consider dispersion and losses. Situations where you can have resonance do exist such as is seen in stars (astro-seismology?). And therefore according to George Dishman rules if a wave only theorist says that an atom is only a node within a resonating contained medium then George HIMSELF has confirmed this to be possible. The interstellar medium consists of atoms and a pressure wave travels through that medium by atoms bumping into each other. You cannot explain atoms as a resonance in the bumping of atoms. Also remember that nodes (and antinodes) are separated by half a wavelength. You might try this with atoms in a monatomic crystal though. And just a seperate question which you may be able to supply the answer. Why does a TV picture on a tube TV reduce slightly before disappearing when the OFF button is pressed? It seems that the whole image reduces in entirety and not just the edges creeping in. This happens within less than a second after the off button is pressed Hey, that's sneaky! It's a long time since I had anything to do with TVs. Do you mean reduce in size or in brightness? George |
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