PopularFX
Home Help Search Login Register
Welcome,Guest. Please login or register.
2019-10-16, 13:44:08
News: If you have a suggestion or need for a new board title, please PM the Admins.

Pages: 1 2 3 4 5 6 7 8 9 10 11 [12] 13 14 15 16 17 18 19 20 21 22 23 24 25
Author Topic: Professor Walter Lewin's Non-conservative Fields Experiment  (Read 251647 times)
Group: Guest

In your examples Gibbs, are your leads in-plane or decoupled, or a mixture of both? I would appreciate the designation of each lead.



I'm afraid this is where we're not clear.  In the experiment where decoupled reading .4V.  The probes wiring are actually cutting half of the loop if from top looking down.  I think you when you say in plane, you actually referring to covering the entire field.

 

   

Group: Administrator
Hero Member
*****

Posts: 2905
It's not as complicated as it may seem...
Gibbs,

I think it is prudent that we adhere to the actual experimental configuration. While it is interesting to look at other hypothetical lead configurations without the presence of a big solenoid coil, this would be departing from the essence of the experiment. Moreover, it serves to obscure the salient points I've had to wrestle you guys on in making my points in this discussion.

May I ask that for now we stick to the diagrams and their associated lead configurations I have uploaded for discussion?
   
Group: Guest
Gibbs,

I think it is prudent that we adhere to the actual experimental configuration. While it is interesting to look at other hypothetical lead configurations without the presence of a big solenoid coil, this would be departing from the essence of the experiment. Moreover, it serves to obscure the salient points I've had to wrestle you guys on in making my points in this discussion.



Yeah, if this is too confusing , we just need to stop.  


Sure, let's just stick to your config.



   
Hero Member
*****

Posts: 1050
@Poynt99
Quote
What "phenomena" specifically are you referring to?
The phenomena of many experts not being able to agree on what happens when a simple loop of wire with two resistors is induced by an external magnetic field, I have no issue with the circuit however the disagreement between the experts is somewhat mindboggling. Let me put this in perspective, we suppose to understand and debate any number of complex subjects here and in the scientific community and yet we still find disagreement on even the simplest things such as this circuit, can you not see the irony in this?. If all of us supposedly understand so much then why do we disagree?, If we understand everything so well then why can't we give a simple explanation anyone could understand? as I said all I see is 11 pages on "non-answers", that is it kind of sounds like an answer but it just ain't because it only leads to more questions.

I believe you have claimed or at least implied you understand why Professor Lewin's experiment gives an answer we would not normally expect, now either you can justify this claim in simple terms anyone can understand or you cannot and it is an unsubstantiated claim --- not unlike the kind you remind so many others here not to make. I simply want to know which one it is as it is impossible to debate an answer which was never actually given.


On a side note keep in mind I am the designated Critics Critic and generally hated by all because I tend to touch on subjects which many consider taboo. Like Milehigh's "Bingo" fiasco, one too many pages of -- no, no thats not the right answer, no that's not the answer Im looking for. Then I find his extremely profound Bingo moment is something I knew some 30 years ago and could find in any grade school textbook. And I thought -- thats your Bingo moment--Really? It made me want to have a chug a 66 of rye and drive my car into a brick wall then vomit kind of moment to ease the pain of having to endure these kinds of posts. I think we can do better, I think we can say what we mean in plain english and debate it like rational adults, I think we can justify what we say using simple terms everyone can understand but that remains to be seen.

Regards
AC


---------------------------
"Great minds discuss ideas; average minds discuss events; small minds discuss people." - Eleanor Roosevelt.

Be careful when you blindly follow the Masses... sometimes the "M" is silent.
   
Group: Guest


Poynt,

You have a theory too how to attain these values.  Let's hear it, maybe we can work it out from there. 

   

Group: Administrator
Hero Member
*****

Posts: 2905
It's not as complicated as it may seem...
I believe you have claimed or at least implied you understand why Professor Lewin's experiment gives an answer we would not normally expect, now either you can justify this claim in simple terms anyone can understand or you cannot and it is an unsubstantiated claim --- not unlike the kind you remind so many others here not to make. I simply want to know which one it is as it is impossible to debate an answer which was never actually given.

I indeed may not be finished with my treatise on this experiment, but you should have been able to draw some conclusions of your own by now based on what has been presented that raise questions about the experiment and the conclusions Lewin's audience departed with. And what exactly did you have in mind in terms of providing an explanation that everyone can understand? It seems to me that you are saying you don't understand what has been discussed thus far, correct? Or is it that you don't agree with what has been said? Or both? Please clarify your stance.

And regarding what my claim is about, I don't think you've got that right. What you stated as your belief of what my claim is, I don't understand. Could you please clarify that as well?

   

Group: Administrator
Hero Member
*****

Posts: 2905
It's not as complicated as it may seem...
Poynt,

You have a theory too how to attain these values.  Let's hear it, maybe we can work it out from there.  

There is only one value that is not so straight forward and easy to come up with just by simple observation, and that is the decoupled measurement when the probes are anywhere other than directly across each resistor. The others I've presented are quite simple to come up with without having to do the actual measurement.

That being said, this "not-so-straight-forward" decoupled value is not that difficult to intuit really, when one knows and understands the following:

a) The induced emf is 1V.
b) The induced emf of 1V is primarily induced in the conductors, not in the resistive material.
c) The induced emf will exhibit a polarity opposite to that of the PD's across each resistor.
d) The radial angle along the conductor for each probe (there will be a slight error because the resistors are of finite length).
e) The length of each conductor is equal.


The in-plane values are easy to come up with when one knows and understands the following:

a) Measurements taken "in-plane", measure the circular electric field (or part thereof) produced by the changing magnetic field.
b) The total electric field produced is 1V, i.e. the sum around the loop is 1V.
c) The circular electric field is present regardless if a conducting loop exists in its path or not.
d) A uniform conductor in the E field's path retains a uniform-intensity circular E field within it because of an even distribution of charge carriers along its length.
e) Rresistors >> Rconductors
f) The introduction of series resistors into the conductor loop causes a proportionate re-distribution of the E field intensity due to an accumulated "lack" and "excess" of charge carriers across the resistors.
   
Hero Member
*****

Posts: 1050
@Poynt99
As far as I know this was your statement or claim from page 1--

Quote
We've discussed this experiment and concluded that Professor Lewin is incorrect in his assessment of his observations made regarding this experiment. The fields are indeed fully conserved, and it is more of a measurement error combined with an assumption which allowed him to come to this conclusion that the voltages measured are different depending on the direction taken.

My first concern was a statement made by professor Lewin in regards to a "non-conservative" field and I did not believe he made this in reference to the conservation of energy as I believe he knows all too well what this implies. Think about that, you don't honestly believe he was referring to the conservation of energy do you?. I believe he was making reference to "conserved" as in the dictionary definition "Conserved:To keep (a quantity) constant" and in his case we could say the fields are not conserved as he believes their qualities have changed and are not constant, that is not consistent with what we would normally expect.
I know there is an impulse to make assumptions especially when someone even mentions non-conservative fields because people get very emotional over these kinds of things because it challenges their beliefs however much of science is about being impartial and not reading something into things which may never have been there. I know all about this because I still do it all the time and thankfully with experience I have learned to catch it through logic and a little intuition.

As well there is the issue of measurement error which would depend solely on the actual equipment Lewin used to measure the variables, it's accuracy and how it was configured. I would assume you must have all of this information do you not? and I would also assume you have exercised caution and contacted someone directly related to this experiment in regards to how the equipment was configured in the actual experiment. If not then what do we actually know of substance?, that which can be proven or disproven based on the facts we have on hand. If their is one thing I do know as a fact it is you had damn well better have your facts in order if you are going to challenge someone as being incorrect if not misguided as it tends to blow up in ones face rather quickly. Let's put it this way, if all this is based solely on a simulation of an experiment which can be proven wrong by the actual experiment then this is definately not going to turn out well in the end.

Im not saying anyone is right or wrong here, Im just saying making assumptions can have a way of turning around and biting us in the ass when we least expect it.

Regards
AC


---------------------------
"Great minds discuss ideas; average minds discuss events; small minds discuss people." - Eleanor Roosevelt.

Be careful when you blindly follow the Masses... sometimes the "M" is silent.
   

Group: Administrator
Hero Member
*****

Posts: 2905
It's not as complicated as it may seem...
How you misconstrued my statement of "conserved" to be COE, I have no idea.

Now, I did not specify, and apologize for that. I was referring to the case when the measurement device is decoupled from the experiment.

Quote
As well there is the issue of measurement error which would depend solely on the actual equipment Lewin used to measure the variables, it's accuracy and how it was configured. I would assume you must have all of this information do you not? and I would also assume you have exercised caution and contacted someone directly related to this experiment in regards to how the equipment was configured in the actual experiment. If not then what do we actually know of substance?, that which can be proven or disproven based on the facts we have on hand. If their is one thing I do know as a fact it is you had damn well better have your facts in order if you are going to challenge someone as being incorrect if not misguided as it tends to blow up in ones face rather quickly. Let's put it this way, if all this is based solely on a simulation of an experiment which can be proven wrong by the actual experiment then this is definately not going to turn out well in the end.

Lewin did a poor job of illustrating the experiment in terms of where exactly the probes were connected. However, for the measurement he was making, it makes no appreciable difference to the observed result anyway. And if you already didn't know why that is, you should know at this point.

Lewin's "measurement error" was largely the measurements that he did not perform for the class. One other faux pas was that he did not explain to the class all the implications of what they had witnessed. Most if not all of Lewin's errors have been exposed in this discussion. I would encourage you to review it.

Now, perhaps you'd be so kind as to respond to the first part of my post?
   

Group: Administrator
Hero Member
*****

Posts: 2905
It's not as complicated as it may seem...
And I'll add this:

AC, if you have anything of value of your own "technically-speaking", to add to this discussion, what are you waiting for? Please do.

Thus far I've not seen anything in that regard.

If you do have a cogent argument which you believe counters my own, then present it. Address each item one by one. We're here to get to the truth and foster understanding, right?
   

Group: Tinkerer
Hero Member
*****

Posts: 1495
This whole discussion has been most instructive.

It demonstrates quite emphatically how easily
deception can be accomplished.

The power of the EGO as a force of distortion.

How when we make certain assumptions it is
possible to believe nearly anything no matter
how improbable.

Professor Lewin has successfully fooled a great
many people.

Is it really any wonder that Truth is often a victim
within the world of academia?

It would be quite easy to duplicate the "experiment"
with an alternating magnetic field to make steady
state measurements and thereby isolate the flaw.

What was the Professor's trick?


---------------------------
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it." Upton Sinclair
   

Group: Administrator
Hero Member
*****

Posts: 2905
It's not as complicated as it may seem...
It would be quite easy to duplicate the "experiment"
with an alternating magnetic field to make steady
state measurements and thereby isolate the flaw.

It would be relatively easy, yes. However I chose to stick to a single capacitive discharge to:

a) stay true to the experiment Lewin performed.
b) get higher current and hence higher induced emf.
c) keep things simple.
   

Group: Tinkerer
Hero Member
*****

Posts: 1495
It is indeed very simple!

The good Professor (a very clever man)
leads us a bit astray while still at the
chalkboard early on - the moment he
erases the electric cell (DC source) and
replaces it with a length of wire.

What is the totality of his circuit once
he includes the loop of wire, the two resistors
and the internal coil which generates the changing
magnetic field?

It's something we make use of each and every
day.

We must be very careful about the assumptions
we make regarding his "circuit."

It bears repeating:  the good Professor is indeed
a very clever man.



---------------------------
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it." Upton Sinclair
   

Group: Elite
Hero Member
******

Posts: 1859
Dumped,

You may find the work of the Prof easy to understand. That is good.

Making the experiment use repeated pulses is not so easy. Yes, the circuitry is easy. The amount of energy used makes it a bit more difficult.

I know. I'm in the process of doing just that  :)


---------------------------
"As far as the laws of mathematics refer to reality, they are not certain; as far as they are certain, they do not refer to reality." - Einstein

"What we observe is not nature itself, but nature exposed to our method of questioning." - Werner Heisenberg
   

Group: Tinkerer
Hero Member
*****

Posts: 1495
Ah yes!  Now you're beginning to understand
why the good Professor chose "pulsing" to
demonstrate the phenomenon - after first
setting the audience up to mis-interpret what is
actually taking place.

It's a classic case of controlled deception.

Once you see how you've been fandangled
you'll slap your head in amazement...

(Error correction)

I must add;  the points Poynt.99 has been trying to
drive home regarding what has been overlooked
or "not measured" is key.
« Last Edit: 2012-03-03, 01:26:48 by Dumped »


---------------------------
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it." Upton Sinclair
   

Group: Tinkerer
Hero Member
*****

Posts: 1495
Most recently, yes.

(Error correction)

Quote from: Poynt.99
Lewin's "measurement error" was largely the measurements that he did not perform for the class. One other faux pas was that he did not explain to the class all the implications of what they had witnessed. Most if not all of Lewin's errors have been exposed in this discussion. I would encourage you to review it.
« Last Edit: 2012-03-03, 01:25:26 by Dumped »


---------------------------
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it." Upton Sinclair
   

Group: Administrator
Hero Member
*****

Posts: 2905
It's not as complicated as it may seem...
That is MY quote.  C.C  Clearly you doctored that....why?

http://www.overunityresearch.com/index.php?topic=739.msg21515#msg21515
   

Group: Tinkerer
Hero Member
*****

Posts: 1495
You are absolutely correct!

Scrolling in too much haste has
caused the loss of sourcemanship.

My error.  I'll make appropriate corrections
to earlier erroneous postings...

You are spot on!


---------------------------
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it." Upton Sinclair
   

Group: Elite
Hero Member
******

Posts: 1859
Ah yes!  Now you're beginning to understand
why the good Professor chose "pulsing" to
demonstrate the phenomenon - after first
setting the audience up to mis-interpret what is
actually taking place.

It's a classic case of controlled deception.
....


Ummm.... Ok?

The professor hasn't deceived me. The moment he first said both meters were connected to points 'A' & 'D' after the setup clearly shows the probes connected directly to the resistors, I caught that minor mistake. I'm sure that is all it was or more probably - he knew it didn't really matter with his setup.

The only other part is where he insisted, loudly, that Ohm's law is always true. For all practical purposes it is always true. In general, as long as it is applied to the device (component, wire section, etc.) and not that device and the world around it, it should always hold true. It can be argued so I was surprised to hear him announce that Ohm's law always holds so boldly.

.99 has clearly shown another part of my objections to Lewin's experiment. There was soooo much more he could have shown with that setup but he didn't. Why? Time to dismiss the class? I doubt it.

In my experience, by the time you are shown that part you have already killed brain cells figuring the rest that could have been shown. I doubt his class needed to see the rest.

Then, why didn't he just say the battery was replaced with an indirect energy source? Well, I suppose he did, didn't he? That, alone, breaks KVL because you can't sum with voltage not in the loop.

Would it all be easier if we used the same definition of Kirchoff? My favorite is the one Maxwell massaged into working conservative or not. I don't have the quote from Maxwell but it goes something like this - the sum of potential differences around a loop is equal to the sum of EMFs around the loop - or was it 'equal to the inverse'? I don't remember.

Regardless, Maxwell and Kirchoff were around the same time frame. I'll trust Maxwell to interpret Kirchoff over dozens of re-writes, adaptations and generalizations since his time.

When you adjust KVL/KCL to work in non conservative fields you are just repeating what Maxwell already did.

Lewin said, "Kirchoff is for da birds!" He is correct. Kirchoff has been for da birds since Maxwell fixed his law that he never wrote and was only attributed to him during his funeral (I read that somewhere while researching this mess about 15 years ago).






---------------------------
"As far as the laws of mathematics refer to reality, they are not certain; as far as they are certain, they do not refer to reality." - Einstein

"What we observe is not nature itself, but nature exposed to our method of questioning." - Werner Heisenberg
   

Group: Elite
Hero Member
******

Posts: 1859
Yes, I am working on the flavor of this experiment I am accustomed to. The whole point of that one was to show all Lewin didn't show.



---------------------------
"As far as the laws of mathematics refer to reality, they are not certain; as far as they are certain, they do not refer to reality." - Einstein

"What we observe is not nature itself, but nature exposed to our method of questioning." - Werner Heisenberg
   

Group: Tinkerer
Hero Member
*****

Posts: 1495
The nature of the energy input to the
circuit is critical to its asymmetrical
voltage distribution.

The circuit isn't normally configured
in circular form but rather in parallel
conductor form.

Transients are tricky...

The good Professor's "mistakes" may be
much more akin to the superfluous moves
a magician makes to draw attention away
from the "magick."

This is not to say that the Professor's motives
were less than honorable.  In the learning
environment deception is sometimes used as
a vehicle to stimulate thought in problem solving.


---------------------------
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it." Upton Sinclair
   
Group: Guest
...
@Ex: You will NOT measure an in-phase PD across the wires, relative to that across the resistors. You need to pay closer attention to the question and diagram being discussed. Your diagram is in reference to the in-plane measurements, while the last question and diagram reference the decoupled mode of measurement, which btw, is the only method of the two which provides the TRUE PD measurement of all the components in a dynamic circuit such as this.

The E field of the EMF/emf in all circuits, whether placed there physically (such as with a battery) or induced through induction, are always, and without exception, IN OPPOSITION  to the E fields of the loads, such as the resistors in our case.

Therefore, the TRUE PD sum of the loop is 0V at any instant of time, or total length of time.

While measuring the in-plane E field however, it is non-conservative, and is always 1V.

The notion that the true PD sum can be 2V (vs. 0V) is ludicrous. You would have a FE generator at your fingertips, if it was.  :P

You didn't understand my previous reply. I was refering to:



As explained, what you measure is really the emf in the half circle 1-D-9 or 1-1'-A-9'-9,  i.e. half the total emf.

The fact to be in plane or out of plane is irrelevant: when you see the circle from above by a projection, you see the wires from the oscilloscope connecting the points 1 and 9 as being along the diameter.
In any case each half-flux leaves each half-circle respectively right and left, therefore they cross the surface of the measurement circuit whatever the height of the oscilloscope. It doesn't a matter you put a micro-oscilloscope just between point 1 and 9 or above this diameter line.

   

Group: Administrator
Hero Member
*****

Posts: 2905
It's not as complicated as it may seem...
Ex. Yes, that diagram measures half the emf. Orientation of the leads DOES matter.

Some relevant points on that diagram and on the in-plane vs. decoupled measurements, are the following:

1) the indicated scope voltage across points 9-1 are different for the in-plane and decoupled lead orientations
2) for V91: decoupled = -0.5V, in-plane = 0.9V
3) the loop emf(s) is opposite in polarity to the PD(s)
4) the sum around the loop IS always 0V, i.e. KVL always holds
5) only the decoupled lead orientation can provide the emf(s) AND PD(s) measurements simultaneously
6) measuring in-plane as Lewin does, provides only half the complete picture, i.e. the E field only
7) the measured E fields and PD's have to be, and ARE equivalent when indicated on the scope
   
Group: Guest
@poynt99
How is generated the primary field? My reply supposed that the dB/dt field is obtained from a concentric coil of same diameter as the circle A-R100-D-R900.
A different case could explain the discrepancies.

   

Group: Administrator
Hero Member
*****

Posts: 2905
It's not as complicated as it may seem...
Yes,

In my case (and I'm quite certain for Lewin's setup as well), the solenoid is only a slightly smaller diameter than the loop.

The loop is located mid-way along the solenoid, and the solenoid length is >> greater than the loop length.
   
Pages: 1 2 3 4 5 6 7 8 9 10 11 [12] 13 14 15 16 17 18 19 20 21 22 23 24 25
« previous next »


 

Home Help Search Login Register
Theme © PopularFX | Based on PFX Ideas! | Scripts from iScript4u 2019-10-16, 13:44:08