Professor Walter Lewin's Non-conservative Fields Experiment

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Author Topic: Professor Walter Lewin's Non-conservative Fields Experiment (Read 329946 times)

marksnoswell	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #50 on: 2011-02-27, 22:45:32 »
Group: Guest	sorry -- perhaps I was not clear enough... A more realistic way to Spice this is to model the circuit as 4 equal voltage sources with differing impedances - one for each side of the receiving loop: R1, link, R2, link back to R1. That is as close to reality as you will get with Spice... it correctly models the induced EMF that is independent or resistance, but rather proportional to length of loop (percentage of total flux cut by the loop).

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #51 on: 2011-02-27, 22:58:28 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	Hi Mark. I probably don't fully understand what you mean exactly, so perhaps you could SPICE it up and show us? But in general, I think I must disagree. The best SPICE can do imo is to emulate what the experiment actually involves. This is what I have done by coupling the solenoid induction coil to the loop wiring. How much closer can you get than that? Isn't the experiment simply a loosely-coupled air-core transformer? Where are my results in error to suggest that this method is not correct or not the most accurate? .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

BEP	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #52 on: 2011-02-28, 03:08:03 »
Group: Guest	Quote from: poynt99 on 2011-02-27, 15:17:14 WW, Sorry that you disagree with me also. I guess MH, ION and I stand against AC, EM, Harvey, and WW on this one. It's not about young or old btw; age is irrelevant when it comes to actual observations. I think what is important and what should be taken away from this discussion, is that observation is what counts, either on the bench, or in a simulator. Definitions and derivatives of one law to form another, is secondary. Also of importance is stating and understanding the goal of what is being demonstrated. ... It is rare that we disagree. Having different perspectives is an asset for any group. Lets just look at it that way Observation is not the only thing that counts. Even more important is what is actually happening. You are convinced a meter connection was swapped. I am convinced it wasn't because the negative swing should have appeared. I'm afraid observations won't silence this disagreement. It hasn't before. In the end I think we'll learn Lewin's lesson was not about physics or electricity. The important thing to note is we should all agree 1V was applied and 1V was returned.

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #53 on: 2011-02-28, 03:50:15 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	Quote from: WaveWatcher on 2011-02-28, 03:08:03 It is rare that we disagree. Having different perspectives is an asset for any group. Lets just look at it that way Agreed. Quote Observation is not the only thing that counts. Even more important is what is actually happening. I had hoped that by using the word "observation", I had implied actual processes. Quote You are convinced a meter connection was swapped. I am convinced it wasn't because the negative swing should have appeared. It is a matter of perspective and goals. I would be interested to hear your take on both, in terms of what this experiment was supposed to be about. From the perspective of traveling along the loop starting at point D, and having the voltage meters oriented as they are, and ignoring the emf produced in the wiring, and traveling in opposing directions from D, yes I would agree the voltage meters should read as Lewin stated and showed. However, is there something unusual that happened there? $:-\$ My question to you and anyone for that matter is this; what was the purpose of this experiment, and what did it prove? Quote The important thing to note is we should all agree 1V was applied and 1V was returned. Can you clarify John what you mean by that statement? Thanks. .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #54 on: 2011-02-28, 06:56:57 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	btw WW, Have you now performed the experiment? .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

Harvey	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #55 on: 2011-02-28, 10:29:03 »
Group: Guest	I see the students are still second guessing the professor. Perhaps this will help. http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/lecture-notes/lecsup41.pdf It specifically addresses the reasons why many textbooks are wrong in their attempts to modify Kirchhoff's Laws. We must recognize here that KVL only applies to an electrostatic field. The reason for this is because it is impossible to begin your integral and end your integral at the exact same instant in time. Therefore, if the field changes before you get back to the starting point the loop will not be zero. This fact is quite evident both in Darren's Scope shots as well as Professor Lewin's scope shots, it is clearly a time changing field i.e. non-conservative. You can tell readily that in both cases (Darren and Lewin) the ground reference for the scope probes is common for both R1 and R2 (on the A side of the resistors). Rewriting the laws to say "instantaneous" or adding unrealistic inductance in order to simulate a voltage source does not solve the problem. In fact, it perpetuates the misunderstanding and obfuscates the core principle of why KVL should be avoided when measuring and calculating nonconservative fields. It is precisely these types of misunderstandings that lead to erroneous claims of "COP INFINITY" in systems dowsed with nonconservative field activity. It can be argued that with fast enough equipment and small enough time slices that we can bury the variances of the loop under the error margins and make everything 'ok' but in reality what we are saying is "I'm too lazy to learn how to apply Faraday's Law, so let me take the easy way out and use KVL - it's close enough" You may be very interested in knowing how Spice arrives at these results. Search this document for the word "Faraday": http://ewh.ieee.org/soc/emcs/acstrial/newsletters/summer09/HowSpiceWorks.pdf

marksnoswell	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #56 on: 2011-02-28, 12:27:33 »
Group: Guest	grrrr... don't have time -- really don't... OK -- here is schematic and output -- didn't have time to mess with values but you can see that the result is essentially as Walter shows experimentally. What he gets is what you expect -- just ignore his explanation. There is no mystery here. ------------------------ Professor Walter Lewin's Non-conservative Fields Experiment Schematic.PNG (12.63 kB, 506x371 - viewed 1396 times.) Professor Walter Lewin's Non-conservative Fields Experiment output.PNG (11.54 kB, 491x472 - viewed 1333 times.)

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #57 on: 2011-02-28, 13:36:16 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	Quote from: marksnoswell on 2011-02-28, 12:27:33 grrrr... don't have time -- really don't... OK -- here is schematic and output -- didn't have time to mess with values but you can see that the result is essentially as Walter shows experimentally. What he gets is what you expect -- just ignore his explanation. There is no mystery here. Thanks Mark. Looks to me that you've just modified my circuit slightly by incorporating inductance and resistance in two of the components. Your results are similar, but I don't see how this proves anything different than what my results are? Anyway, I will look at the lecture supplement that Harvey uploaded. Just skimming it so far has revealed some interesting things. This ain't over. LOL. .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #58 on: 2011-02-28, 13:41:08 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	I have a question for all here, and in particular to those in disagreement with the simulation results and conclusions: Are points A and D on Lewin's diagram the same as the two points directly across each respective resistor R1 and R2? .99 « Last Edit: 2011-02-28, 14:45:13 by poynt99 » --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

Allcanadian	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #59 on: 2011-02-28, 16:14:21 »
Hero Member Posts: 2735	@All I think the most interesting part of this circuit concerns the fact that here we have very many knowledgable people who cannot seem to agree on what occurs in a circuit comprised of two pieces of wire joining two resistors in a loop, lol. Can you imagine such a thing, we assume we know so much and yet the dabate over such a simple circuit extends into areas where the supposed experts including professor's who are teaching our future generations cannot even agree ---- about two pieces of wire joining two resistors. To be honest this does not instill a great deal of confidence in me that anyone knows what their doing, that maybe we believe many things not because they are a fact or because we have verified them as fact but because someone simply told us they are facts and we believed them. What I find even more troubling is the fact that we seem to have no shortage of opinions here but nobody can seem to be bothered to actually ,in reality, join two resistors together with two pieces of wire and prove the matter for themselves, lol, priceless. Friday I built a 500KV Van De Graaff generator as well as a variation of a Belli machine with a multiplying function for my daughters science project so I am quite confident I can manage joining two resistors together with two pieces of wire and providing some actual facts for the people here. Regards AC --------------------------- Comprehend and Copy Nature... Viktor Schauberger “The first principle is that you must not fool yourself and you are the easiest person to fool.”― Richard P. Feynman

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #60 on: 2011-02-28, 17:45:54 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	GO AC! --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

wattsup	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #61 on: 2011-02-28, 19:03:46 »
Hero Member Posts: 520	If I understand this correctly, then here is why you have so many questions. It is because you are only observing one set of wires/resistors placed around one plane of that solenoid. If you used more wires layered one on top of the other with that solenoid placed inside then you will have more perspective on the effect and this will give you a better idea on what's going on. I had made this diagram shown below a few days ago but forgot to post it. By using more wire/resistor sets and seeing if there is or not any differences between the sets, this will give you a better picture of what's going on. First of all, according to my own understanding, the solenoid when energized, (well forget it because what I really have to say will just be taken again as mass drudgery so I will play the standard game), each end of the coil will produce a magnetic polarity. The north and south polarity are each turning. Some will say the poles turn in opposite directions, but I do not agree with that. I think they turn in the same direction but it is only the perspective that changes. Like if a tornadoes tail was passing through the solenoid always turning one way but you see two directions if looked down from the north or from the south. Actually, if you used many coils wound in the identical way and stacked them with the solenoid in the center, then measured output off the coils that are each connected to a separate volt meter all in the same manner, you will see it right away if the reading is going from + or - or if they are all the same polarity or if they are all random. lol wattsup ------------------------ Professor Walter Lewin's Non-conservative Fields Experiment single-multiple-circuit1a.jpg (109.19 kB, 392x715 - viewed 1272 times.) « Last Edit: 2011-02-28, 20:36:44 by wattsup » --------------------------- http://etherimpress.com

EMdevices	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #62 on: 2011-02-28, 21:10:25 »
Hero Member Posts: 805	this simple circuit experiment has a lot more to teach then KVL limitations and assumptions. The interesting phenomena here is that the voltmeters will register different voltages depending on their location or angle relative to the circuit plane. These kinds of problems are not for the Circuits 101 student, but for the electrodynamic crowds that understand magnetic induction and can integrate. EM ------------------------ Professor Walter Lewin's Non-conservative Fields Experiment induction_problem.JPG (9.28 kB, 399x249 - viewed 1228 times.) « Last Edit: 2011-02-28, 21:52:07 by EMdevices »

Harvey	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #63 on: 2011-03-01, 21:29:22 »
Group: Guest	Quote from: poynt99 on 2011-02-28, 13:41:08 I have a question for all here, and in particular to those in disagreement with the simulation results and conclusions: Are points A and D on Lewin's diagram the same as the two points directly across each respective resistor R1 and R2? .99 No. Essentially you have +1/2V from A to D with respects to R1 and +1/2V from D to A with respects to R2. Therefore, you have +1V from A to A around the closed loop, or +1V from D to D around the closed loop. This is the nature of the nonconservative field in transition inducing an EMF in a loop of conductor. Consider that I have drawn attention to the inductance of the wire a couple of times which would be (SWAG) 5.12 nH for a #4AWG at 4" long according to the calculator I have posted a link to here before. So that is part of the clue as to how EMF is being produced in the loop, but it is only a fraction of the equation. Lewin was quite specific with regards to the area of the solenoid and even took pains to shade it in in the drawing. There is good reason for that, because that too is part of the equation. Let me illustrate the problem like this: You get in your car and drive 100 miles in a convoluted loop of hills and valleys ranging from 100 feet below sea level to 14,000 feet above sea level. You record your mileage, compass heading and elevation at every 10 minute mark. Upon arriving back home you tally up each thing. First you add up all the compass headings and realize that it totals to zero. Then you add up all the elevation changes, these too add up to zero. Then you add up your mileage, being careful mind the polarities of N and E = plus while S and W = minus and again, the result is zero. KVL HOLDS! Fantastic. Now the next day, you do the same thing. But little did you know that half way around the loop an Earthquake occurred and your home elevation was lifted to exactly 10 feet higher than it was before. The closed loop integral of the compass readings is still zero, the mileage is still zero, but the elevation is not zero. KVL failed. Bummer. So you dig into the matter and find out why it failed. Then you say "no problem, all I have to do is change what Gustav stated in his Law originally and introduce a new factor to account for the difference. (That's what we do in Spice, we introduce a specific variable in the inductors that allow us to fool the KVL routines) KVL is based on an electrostatic field. Faraday's Law is based on a dynamic field because it is rooted in the change of flux over the change in time (Borrowed from http://en.wikipedia.org/wiki/Faraday%27s_law_of_induction) Consider the attached image. I have purposely excluded the polarities so that you don't know which way the current is nor the direction of the induced EMF. It is a flat sheet of copper with holes punched out and resistors soldered in place. A dotted line shows a solenoid in the back ground. What conditions are necessary so as to produce a 0.1V drop across the left side resistor (call it R1) and a 0.9V drop in the right side resistor (call it R2) ? Which law is best suited to solving this problem, KVL or Faraday's law? Harvey ------------------------ Professor Walter Lewin's Non-conservative Fields Experiment Flat Sheet.PNG (26.81 kB, 1024x768 - viewed 1202 times.)

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #64 on: 2011-03-02, 15:22:11 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	Thanks Harvey for your responses and your time and effort in trying to help my stubborn mind understand. There are several comments and questions I have from your responses, however I am holding those back for now while I hopefully contemplate posted results of the actual experiment. AC has expressed interest in doing the test, and I've been advised by WW that he too will be doing it and posting his results. I will however respond to one point in your recent post. The loop inductance calculator I found and used gave me a result that corresponded very closely with what my chosen values are for the interconnecting wiring. http://www.qsl.net/in3otd/ind1calc.html Judging from the MIT video, I estimate the solenoid diameter to be between 4 to 6 inches. I also estimate the loop to have a circumference of about 0.75m (it does not appear to be closely-wound on the solenoid). Try 0.75m for the "perimeter", and 1mm wire diameter. The result is 833nH, and I used a total of 800nH in the first schematic. .99 EDA: I should also mention that the actual inductance values present in the loop wiring is of little consequence to the results of the experiment anyway. The induced emf will vary according to relative inductance and K factor between the solenoid and the loop, but the ratio of voltages measured across the two resistors, is a constant, regardless of the total induced emf. Therefore over all, the actual inductance of the loop wiring in relation to the solenoid coil is largely inconsequential to the resulting different voltages and their polarities. EDA2: The inductance result with your calculator and my parameters comes to 1088nH. Note that the calculator you provided is for a straight piece of wire, mine is for a circular loop, which of course is what professor Lewin would have placed around the solenoid. « Last Edit: 2011-03-03, 02:18:19 by poynt99 » --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #65 on: 2011-03-03, 03:29:52 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	Quote from: Harvey on 2011-03-01, 21:29:22 No. Essentially you have +1/2V from A to D with respects to R1 and +1/2V from D to A with respects to R2. Therefore, you have +1V from A to A around the closed loop, or +1V from D to D around the closed loop. This is the nature of the nonconservative field in transition inducing an EMF in a loop of conductor. In regards to the 1/2V drops, is this in line with what professor Lewin is saying? I'm confused. See "Lewin_path01.png" below. Quote Consider the attached image. I have purposely excluded the polarities so that you don't know which way the current is nor the direction of the induced EMF. It is a flat sheet of copper with holes punched out and resistors soldered in place. A dotted line shows a solenoid in the back ground. What conditions are necessary so as to produce a 0.1V drop across the left side resistor (call it R1) and a 0.9V drop in the right side resistor (call it R2) ? Which law is best suited to solving this problem, KVL or Faraday's law? Harvey First, you need a homogeneous field, and you will not attain one with a solenoid placed as you described. Your version would require a Helmholtz coil with your copper board situated in the middle. Having said that, there needs to be changing flux from the coil to induce an emf in the copper foil. This is essentially the same scenario as Lewin's setup, but with his, the current is confined to the wire loop. In yours, the current will flow along the path of least impedance. In regards to solving the "problem", please re-state what the "problem" is from your perspective Thanks, Darren ------------------------ Professor Walter Lewin's Non-conservative Fields Experiment Lewin_path01.png (105.96 kB, 320x240 - viewed 3735 times.) --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

Harvey	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #66 on: 2011-03-04, 08:32:39 »
Group: Guest	Quote Hi Darren, First, the Helmholtz coil in unnecessary, all that is needed is for a change in flux to occur in the copper, and this will as the solenoid is energized. A uniform magnetic field is what is prescribed. You don't get that at the end of a solenoid. Quote The proposal by Kirchhoff is that the sum of those two line integrals from A to D and D to A, or alternatively as shown D to A via R1 and D to A via R2 should equal zero. But for that to work E must be stable, and when E is stable there is no induced EMF and if there is no induced EMF then the EMF everywhere is zero and KVL would hold. KVL holds in both dynamic and static conditions. It is the measurement method that is in error, not the application of KVL. Quote Why is it a bad idea to try and force KVL to work in changing magnetic fields by introducing changing power sources to match the drops? It is perfectly valid to use KVL when the circuit and measurements are fully understood. .99 « Last Edit: 2011-03-13, 05:05:22 by poynt99 »

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #67 on: 2011-03-05, 00:32:14 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	Harvey, What professor Lewin is discussing at that moment of the video (7:10, part1), is that if we go from D to A (or A to D), the answer depends on the path. Going through the left-hand path, we get -0.1V. Going through the right-hand path we get +0.9V. You said this: Quote Essentially you have +1/2V from A to D with respects to R1 and +1/2V from D to A with respects to R2. ...which seems to contradict what the professor is describing and illustrating on the board. So, I am confused by your statement. Darren « Last Edit: 2011-03-05, 01:06:18 by poynt99 » --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

Harvey	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #68 on: 2011-03-08, 13:36:54 »
Group: Guest	Hi Darren, http://www.youtube.com/watch?v=eqjl-qRy71w#t=7m40s Perhaps you didn't watch it to the end? Just after the Professor tells us NOT to use Kirchhoff's Law with that demonstration you are alluding to at 7:10, he discusses going from D to D for around the whole loop as I have alluded to in my prior posts. The whole loop is 1V as he clearly shows, Kirchhoff demands the loop to be zero. Remember my illustration regarding the earthquake earlier? That was to help you grasp the non-conservative action of a changing magnetic field. As regards the 1/2V references, I went into some detail on that in my prior post. I'm sorry if you are still confused on that matter, but I'm running out of ways to explain it to you, and quite frankly I know you are much smarter than you are letting on there - in fact, I would venture a guess that you are not confused at all, but that you are trying to find something to argue about and this is an apparent discrepancy and you think you are exposing a flaw of some sort. You are mistaken. Since the Professor and I both agree that there is 1V from D to D around the closed loop, then it stands to reason that there is 1/2V from D to A or from A to D because the circuit is in parallel when evaluating only half of the measurement. In this case I am offering an alternate 'outside the box' perspective for viewing the events in place by giving an "essentially" equivalent scenario that includes the sources within the network. The professor however, is addressing the issue that the sources do not exist and the EMF is introduced dynamically via induction. We are both adding EMF to the circuit, but in different ways. In my case I draw attention to the fact that using the "length" in the calculation offers us the ability to actually measure the size of the wire and the size of the resistors. This is a very important thing to consider when answering your question regarding whether or not A and D are the 'same' as measuring right at the resistors. It is clearly not the same, because there is a connecting wire between them. Therefore, an EMF must exist between D and R2 and it must be an arbitrary value that was not measured, but we know it exists because there is "length" between D and R2 and an EMF is present in that length. So if I measure 0.5V from D to A, and 0.9V across R2 then I know that somewhere between D and R2 there is an EMF and somewhere between R2 and A there is an EMF and that combined EMF must be equal to 0.4V. If it were completely linear, and I don't expect it is, then we could say that we have a +0.2V from D to R2 and a -0.2V from R2 to A which results in the 0.9V across R2. A similar thing could be present for R1 But with greater magnitudes. The only reason I picked 1/2V for A to D and D to A was because these points are drawn equidistant and I arbitrarily chose to split the 1V down the middle to illustrate the importance of NOT assuming D or A was positioned directly on the resistors. Perhaps the entire exercise would have been less confusing for you if we removed the wires from the circuit as I mentioned in my prior post. Imagine a carbon ring that has an asymmetrical resistance. From exactly 0° to 180° it measures (non parallel) 900 ohms to the right and 100 ohms to the left. Now we can place A at 0° and D at 180° and your question regarding the position of A and D would be true. In that case, no wires would exist other than the conductivity value of the carbon ring. Then we can use all the same parameters as before and everything Lewin stated would be true, your sim would fail and my 1/2V insertions would vaporize. I think that would finally put an end to your confusion. I hope that helps Harvey

Allcanadian	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #69 on: 2011-03-08, 18:36:15 »
Hero Member Posts: 2735	@All Perhaps a simple analogy is in order, I have a toy train set on a circular track now if the beginning of the train is connected to the end of the train then the train is continuous and if I apply an external point of force anywhere on the train the whole train must move equally. However it should be painfully obvious that the train cars ahead of the applied force are pushed together and the train cars behind the applied force are pulled apart as well if part of the train is pushed and another part is pulled then on the opposite side of the track where push meets pull there must be a singular point where the train car is neither pushed nor pulled, it is both and neither and the forces sum to zero. Now if on the left side of the track I have a resistive hump 1cm high and on the right side of the track I have a resistive hump 9cm high and every train car has an equal applied force then something interest happens. The greatest measurable force pushing the train cars together is obviously just "before" the 9cm high hump on the right hand side and the greatest force pulling the train cars apart is obviously just "after" the 9cm high hump on the right hand side. At the very peak of the 9cm hump there must be a singular point where a train car is both pushed from behind and pulled from the front and between these forces of push and pull there is a singular point that has both and neither forces applied or sums to zero. Now let's consider the left hand side of the track where we find the rather small 1cm high resistive hump in the track, obviously the train cars before the 1cm hump are pushed together and the train cars after the 1cm hump are pulled apart but we have one little problem here. Can you see it? If not then draw a sketch of the system. The problem here is that the greater forces pushing the train cars "together" before the larger 9cm high resistive hump on the right have extended all the way back through the train cars and onto the 1cm high hump on the left, the train cars falling down the 1cm hump on the left are not being pulled apart they are being pushed together by all the other cars before the 9cm hump on the right. As well we find that all the train cars falling "after" the larger 9cm hump on the right are being pulled apart but at one singular point the train cars cease being pulled apart and start being pushed together very near the smaller 1cm hump on the left. If we examine the forces in this system we find that the greatest difference between the push and pull forces is directly across the peak of the larger 9cm hump on the right, we also find that the smallest difference in forces occurs very near the peak of the smaller 1cm hump on the left. That is the difference in forces across the larger 9cm hump is a large number and the differences in forces across the smaller 1cm hump is a small number near zero. It should be obvious when we look at the differences in the forces involved that there is no way in hell the numbers on the right and left could possibly sum to zero, that is absurd. Maybe I am simple minded because I never cease to be amazed even when considering things as simple as a child's toy and all the dynamics involved. If you want to understand the dynamics of the Prof Lewis circuit simply replace the train cars with free electrons, the "humps" or hills with a resistance and consider that each train car or free electron has a singular external force applied to it. Regards AC --------------------------- Comprehend and Copy Nature... Viktor Schauberger “The first principle is that you must not fool yourself and you are the easiest person to fool.”― Richard P. Feynman

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #70 on: 2011-03-08, 23:57:00 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	Harvey, I'm sorry that you take me as being disingenuous. I'm mainly interested in technical discussions and understanding the point of view of others regarding this experiment. I believe I have a good grasp of this experiment and I do not yet buy into the assertion that professor Lewin et al are promoting, but I am also trying to understand why others see something different than I do. I have difficulty understanding what people write sometimes, which is why I have been asking you for clarification, that is all. It seems to be upsetting or frustrating you though, so I'll simply refrain from discussions on this topic with you, until perhaps a later date. As it seems no one else is really interested in this discussion, I guess it may be quiet here for a while. Cheers, Darren --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

BEP	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #71 on: 2011-03-09, 04:12:49 »
Group: Guest	Quote from: poynt99 on 2011-03-08, 23:57:00 I'm mainly interested in technical discussions and understanding the point of view of others regarding this experiment. I believe I have a good grasp of this experiment and I do not yet buy into the assertion that professor Lewin et al are promoting, but I am also trying to understand why others see something different than I do. To that end.... One of the points about voltage drop sticks in my mind. I'll try to explain it in my current foggy mind state (it has been a long day). Using the generalized KVL to produce the result of zero requires the addition of voltage drops across inductors. It is easy and common to think this is realistic but in reality... It doesn't make sense. Mind you... I find Lewin's explanation of the measured voltage drop interesting but don't quite think it is completely correct.(The thing where the actual voltage drop being measured is of the meter input circuit not the drop across the inductor.) Using our favorite spring analogy, voltage drop across an inductor makes even less sense. If you apply a compression force to the free end of a spring, the other end secured in position, the spring compresses and stores the energy being applied. At any point in time during the compression the force applied to the free end is equal to the force applied by the spring to the securing surface at the other end. (not talking about breaking the sound barrier when compressing the spring ) In other words, the voltage difference between the ends of an inductor is zero. There is no voltage drop across an inductor. The force isn't delayed from one end of the inductor to the other. Of course, this isn't always true but I'm talking about this situation. 'Single Pulse and not considering wire resistance' So, KVL being what it is - a law about electric fields - does not apply to an inductor. There is no electric field across an inductor. So what did the wires do? They were voltage sources during the pulse induction. The simulation would be more correct if you replaced the wires with batteries (for that couple of milliseconds). The problem with that is they would each be required to produce 1/2V. The reason I say that is the total voltage dropped across the resistors is 1.0V. The reason I say that is KVL is an electric field only law. It cannot be applied in it's original form due to the wires becoming transformer secondaries - due to Faraday's laws. So what law could be used without mangling it for ease of obtaining results while using completely incorrect methods and not espousing obfuscation nor eschewing elucidation of what is really happening? (Cough, Cough, gag!) Faraday's. The problem is some will still be stuck on the odd looking results. I'm referring to the -.1 + .9 volts. or the voltage drop across the resistors. That adds up to .8V Using Faraday the wires become voltage sources. This means their sine changes. Granted, since 'time' is now part of the equation due to induction things become unclear for many. Just like KVL has become. You can simplify the problem by rearranging the circuit. You can do that. This is a series circuit. Put the two voltage sources together. They add up to 1V. Put the resistors in series together. They add up to 1V..... Yes, they do. Another fine point no longer clarified... simple measured potential is the measured difference between 2 points. The difference between -.1V and +.9V is 1 Volt. The voltage sources add up to 1 Volt. Since sources and loads are algebraically added with opposite sine... The result is zero Volts. I don't really care because Kirchhoff didn't use the word 'zero', or the German equivalent. It all still works but is harder to obtain. (Even when doing it verbally and not exactly correct according to Faraday) At least the hard way means better understanding of what really is going on. This understanding includes things like: ...Zero potential is BS. It is only a reference point to hang your brain on. Like kissin' cousins say, "Its all relative" ...When an unaccounted for variable jumps in it is time to apply a law that includes that variable, not time to 'adjust' the one you understand. Just because the result is correct doesn't mean the method was. ...a current loop can take the same path it would through a loop of wire - even if you replace that loop of wire with the negative equivalent - a sheet of copper with slots for the resistors. ...Rise and fall times do matter One point is... Applying some mangled form of a perfectly good law may get the correct results but it doesn't help folks understand what is actually happening. One result might be somebody using the reliable and correct spring analogy one moment and then.... contradicting the same idea the next. Not picking on anyone in particular. I'm guilty of exactly the same thing. I'll admit to not being precise but the point was to get the point across and give .99 some reference for my opinions on this subject.

poynt99	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #72 on: 2011-03-09, 04:50:09 »
Group: Administrator Hero Member Posts: 3217 It's not as complicated as it may seem...	Thank you WW for expressing your POV. .99 --------------------------- "Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

Allcanadian	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #73 on: 2011-03-09, 16:43:01 »
Hero Member Posts: 2735	@Wavewatcher Quote So what law could be used without mangling it for ease of obtaining results while using completely incorrect methods and not espousing obfuscation nor eschewing elucidation of what is really happening? (Cough, Cough, gag!) Well, we could try the laws of nature instead of distorting the truth to fit the laws dictated by any one person. Quote You can simplify the problem by rearranging the circuit. You can do that. This is a series circuit. Put the two voltage sources together. They add up to 1V. Put the resistors in series together. They add up to 1V..... Yes, they do. Does it sound reasonable that we should have to completely change the circuit thus the effects so that it agrees with any given law? Quote Another fine point no longer clarified... simple measured potential is the measured difference between 2 points. The difference between -.1V and +.9V is 1 Volt. The voltage sources add up to 1 Volt. Since sources and loads are algebraically added with opposite sine... The result is zero Volts. I don't really care because Kirchhoff didn't use the word 'zero', or the German equivalent. Does it sound reasonable that we should have to start changing all the figures and facts so that they agree with any given law? You see in science most would find it unreasonable that when someone does not like the results of an experiment they completely change the experiment and the results then call it the same thing as the previous experiment. It just does not sit well with the scientifically minded because it is a complete distortion of the facts and science is about facts not laws. Quote ...Zero potential is BS. It is only a reference point to hang your brain on Here is something to consider, we are all intelligent and reasonable people but what if you examined everything with a magnifying glass and all your facts were based on this. Then someone came along with new facts that contradicted your own, it is natural to assume they may be wrong, but what if this other person was using a microscope magnitudes more powerful that your magnifying glass?. Let's put this in perspective, while you may be using an off the shelf multimeter and oscilloscope I use an instrument I invented which can detect the change in potential when my dog walks across the carpet on the other side of my house. While you are bound to the limited measurement of potential between two points I measure the instantaneous absolute potential at one singular point not relative to "one" other point but "every" other point because my reference is not a point it is a field which as you know are spherical in nature. I understand this is completely beyond your level of understanding and it makes no sense whatsoever but this is how science works, when we develop better instruments we get better facts. Regards AC --------------------------- Comprehend and Copy Nature... Viktor Schauberger “The first principle is that you must not fool yourself and you are the easiest person to fool.”― Richard P. Feynman

BEP	Re: Professor Walter Lewin's Non-conservative Fields Experiment « Reply #74 on: 2011-03-09, 23:57:43 »
Group: Guest	Ok. Hmmm.... I guess it is my turn. I'm not distorting the truth. I offered my opinion. I didn't change the circuit to change the effects or the truth. Sometimes you can look at things from a different perspective in order to gain understanding. That is another scientific tool. Figures and facts changing? - Never mind. >>Edit... Sorry AC. Your post caught me at a bad time. No reason for me to share the bad times here. « Last Edit: 2011-03-10, 02:47:08 by WaveWatcher »

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