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"Veritasium" (YT) - "The Big Misconception About Electricity" ?
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Naej:
Yes it's flawed. So you have to correct your intuition about A, or compute the integral.

I mean you literally found no problem in Carpenter's proofs that energy flows in wires. Because it's correct. So just admit it, and move on.


--- Quote from: Sredni on January 14, 2022, 11:02:52 pm ---Dude, that's Stratton. One of the most cited textbooks in EM.

--- End quote ---
Yes. Did he prove that it was wrong to say energy flows in wires? No.

--- Quote from: Sredni on January 14, 2022, 11:02:52 pm ---But he acknowledges the same points made by Stratton in 1941 and has a little paragraph that says "It may seem odd that the Poynting vector for a wire circuit does not predict energy flow parallel to the wire itself. This and other unanticipated features of some Poynting flows prompt some authors to define a Poynting vector using S = E x B/mu0 + curl X. The vector field X is chosen to make [the Poynting vector] point in more “natural” directions. The [above] definition does not disrupt Poynting’s theorem because the latter contains only ∇ · S. Relativistic considerations constrain, but do not completely eliminate, this arbitrariness in the definition of S.
There is no real problem in any event because the Poynting vector is not an observable."

--- End quote ---
That's right it's not an observable. So you can claim that the energy flows in wires. And you can also claim that energy flows from battery to the lamp by going behind the Moon.

--- Quote from: Sredni on January 14, 2022, 11:02:52 pm ---Point is: you have to choose a theory and stick to it.

Do you use voltages and currents, and consider current as a flow of charge carriers? Stick to classical ED (it automatically incorporates special relativity) and learn how to correctly apply Maxwell's equations

--- End quote ---
Yes.

--- Quote from: Sredni on January 14, 2022, 11:02:52 pm --- (to the point of being able to tell that the Poynting vector does not point directly towards the battery - or even good conducting wires - at DC because you've seen a picture on Feynman where it points radially in, in a resistive wire).

--- End quote ---
No. It's not in Maxwell's equations. It's not about an observable.
There you can see 729 variants of Poynting's theorem. You do not have to know for each what it will give in the battery/resistor situation. This is poyntless.
https://physics.princeton.edu//~mcdonald/examples/variants.pdf
EEVblog:

--- Quote from: bsfeechannel on January 14, 2022, 11:37:29 pm ---
--- Quote from: EEVblog on January 14, 2022, 09:48:38 pm ---
--- Quote from: Naej on January 14, 2022, 02:00:47 am ---tl;dr : energy flows in wires. Or in vacuum. Whatever.

--- End quote ---

I'm begining to think that Derek/Ponyting can no more correctly claim that the energy actually flows outside the wires than QFT says it flows mostly inside the wire.
--- End quote ---

You see? It is you that are saying that. What "QFT" professor said is just that the probability of an electron interacting with another in the wire is greater than that of an electron interacting with another one 1 m apart. You jumped automatically to the conclusion that the energy flows in the wires due to your bias.

That's how misconceptions spread.

The "QFT" professor said that her field of research is not related to QFT. I suggest you interview a specialist in the study of QED to analyze Derek's claims and provide an unbiased conclusion.

--- End quote ---

I've used the word "probable" multiple times in relation to this. I may have dropped that word a few times becaus it's getting monotonous. And you kinda can when it's (for example) 99.9% probable it's inside the wire.
Yes, I've tried to do my own research and didn't get very far, but from what I've read, this seems to be what QFT predicts.

You guys don't seem to like it because it seems to predict contrary to what Poynting and classical theory predicts. All of you were all gung-ho beating everyone with a Poynting stick until QTF was brought up. Now it seems like the eyes are darting around, because maybe, just maybe, you might have been trumped.
And even Sredni is posting his own references that say "hmm, maybe it's not quite right/complete".
Naej:

--- Quote from: EEVblog on January 14, 2022, 11:37:07 pm ---Once again, the fundmental question being asked here is whether or not energy flows inside or outside the wire.

--- End quote ---
Just to be clear: this is not a question which can be settled with experimental evidence (unlike what Stratton said or implied).
This is a case of: should you say that the origin is in the center of the Earth, or in the center of the Sun/Solar system.
And the correct answer is: it depends what you're doing, both are correct (until someone finds a flaw in Carpenter's computations… but don't wait for it).
bsfeechannel:

--- Quote from: SiliconWizard on January 14, 2022, 10:15:38 pm ---A lot of the "debate" coming more from using different (or even vague) definitions and a philosophical approach of science rather than experimental, it can probably go on forever. =)
Just like with the KVL one.

--- End quote ---

The idea that energy flows in the wires creates a lot of problems. For example, a dipole antenna is just an open transmission line. People struggle to understand how the "electrical" energy flowing in the transmission line gets converted to "electromagnetic" energy that can travel in the free space. Wait a minute. Isn't the energy flowing in the transmission line already "electromagnetic"? If you understand that the energy is already in the fields in the space around the wires, it is easy to see that  what the antenna does is just to provide a convenient geometry for the fields to propagate with maximum efficiency. No magic is going on there.

I showed an example of transmission of energy with a linear DC motor. The movable part of the motor is not galvanically connected to the solenoid (the stator). Energy flowing in the wires does not explain how that's possible.

Naej:
If you want to explain, you use Maxwell's equations.

If you want to tell a story/tale about energy then you can tell yours, or you can tell the following one: a dipole antenna has radiation resistance, so it takes the energy from the wire and removes it (not only in a ohmic way);  and a motor converts the energy coming from the wires into mechanical energy.
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