"Veritasium" (YT) - "The Big Misconception About Electricity" ?

[rfeecs]

Carpenter's theorem states that if Maxwell's equations are correct, then JV is a valid energy flow. And with JV, energy flows only in wires.

So either:
a) you find a flaw in the 3 lines proof of the theorem
b) you find a counter-example to the theorem
c) you compare Maxwell's equations to flat earth-theory.

Conclusion: the statement "energy flows only in wires" is correct.

So it seems that Carpenter's approach assumes that energy does not flow through empty space.  It only exists where charges are present.  It can get from one point to another, from a transmitting antenna to a receiving antenna for example, by the retarded potential.  All we care about is what happens to charges, anyway.  So it is perfectly useful and still completely consistent with Maxwell's equations.

If we see a high power laser beam that seems to be glowing along it's path, that's just the result of the charged particles that it is bumping into.  Not energy "flowing" along the path.

It seems a bit counter intuitive to old folk who are still used to the idea of a wave flowing through the aether.

So you have the Poynting vector which is counter intuitive for DC, and Carpenter's approach which is counter intuitive for radiation.

Both are mathematically correct models, so let's just give it up and say it doesn't matter?  Use the one that is easiest for the problem at hand?

[Naej]

Exactly! These concepts are tools.

[SiliconWizard]

Current "goes through" (and Carpenter's flow does the same) the capacitor, and on the other side, wires move energy into the bulb.
Yes the theorem is entirely true.

Well, yeah... It seems like people are suddenly discovering capacitive and inductive coupling?

Dave made a video about this way before Veritasium actually. "Does Current Flow Through A Capacitor?" =)
(Yes of course we are all running in circles.)

[EEVblog]

Exactly! These concepts are tools.

Careful, I've been constantly put down on this thead for being a dumb arse engineer for dare suggesting that engineers have tools that solve problems, and not understanding that Poynting is the only true way that energy flows 

[SiliconWizard]

Exactly! These concepts are tools.

Careful, I've been constantly put down on this thead for being a dumb arse engineer for dare suggesting that engineers have tools that solve problems, and not understanding that Poynting is the only true way that energy flows 

That is because " Engineers are essentially dumbed-down "physicists". "
 

[Naej]

Well now all EE's are under the protection of Carpenter's theorem; and can answer by saying "there is no energy in light". 

[rfeecs]

So, uh, what about photons?

From https://en.wikipedia.org/wiki/Photon:

To explain the photoelectric effect, Einstein introduced the idea that light itself is made of discrete units of energy.

Yet another tool to use in the right situation.

[HuronKing]

So, uh, what about photons?

From https://en.wikipedia.org/wiki/Photon:

To explain the photoelectric effect, Einstein introduced the idea that light itself is made of discrete units of energy.

Yet another tool to use in the right situation.

Indeed and I was thinking about this when reading Carpenter's interesting papers posted by Naej. His mathematics is equivalent in terms of computing P_{out} versus P_{in} but I think there is some sly subtlety in the language he uses to describe, for example, in the section Magnetic Materials and Transformers he says:

The core, represented largely by an equivalent surface current J, , has the effect of a flywheel, into which the primary injects and recovers momentum by the remote action effect of A. The electron stream in the secondary conveys energy into the load, which generates a p4/2 pressure in the winding, and hence controls the rate at which energy is extracted from the ‘fluid."

Hmm, what is this "remote action effect"? Does he just mean... field effect? But doesn't want to say fields?

And then later,

Once f is known everywhere, then the energy transferred by the moving charges is given by in accordance with eqn. 13, and the antennas are no different in this respect from the plates in Fig. 1, or from the wires in Fig. 4a. Both examples illustrate the way in which removing the energy from empty space also removes the energy flow vector which is needed to account for it, and makes the question of the ‘mechanism’ of energy transfer wholly irrelevant. The mutual energy is divided between the charges, so that they necessarily become the vehicle by which the energy is transferred. It
is, perhaps, remarkable that, although Maxwell’s attempts to use field theory to develop a mechanistic aether model have been universally abandoned, and with them the possibility of any useful meaning to the concept of the field as providing a force transfer mechanism, the properties of mass, energy and momentum in empty space are still interpreted literally, and go largely unchallenged

And earlier in energy exchange in a capacitor:

However, the mechanisms of the electromagnetic interactions, all of which are remote, are of no interest to the engineer if they are not needed to predict the behaviour of electromagnetic devices, and the general objective of Reference 2 was to show that this is so. As J4 satisfies the stored energy and force requirements, the point which remains is not whether it is a ‘correct’ description of energy flow (a question which is clearly meaningless in view of the variety of the alternatives), but whether or not it is sufficient for practical purposes.

So, all I'm getting from his paper is that he doesn't give a damn what happens in the middle (and uses the ad hoc 'remote action effect' term) - all he cares about is the end result. How much power is delivered from source to load?

But, this interpretation seems to be insufficient to answer Derek's question about how long it takes for the bulb to receive energy in the transient period. The mechanism of EM interaction IS important to Derek's question (that EM energy can traverse empty space at speed c, and if so, how?) - otherwise you'd be led to the wrong answer.

Classically, it's all fields.

In QM/QED, we talk about photons (which I suppose from my understanding are themselves compositions of the energy in fields in QFT).

PS
If there is no energy in light - then what is radiation pressure?

[Sredni]

Exactly! These concepts are tools.

Careful, I've been constantly put down on this thead for being a dumb arse engineer for dare suggesting that engineers have tools that solve problems, and not understanding that Poynting is the only true way that energy flows 

Let's see. Minute 8:50 of your video

Derek's voice: "The charge on the surface of the conductor also creates an electric field outside the wires, and the current inside the wires creates a magnetic field outside the wires. So now there is a combination of electric and magnetic fields in  the space around the circuit, so according to Poynting theory energy should be flowing. We can work out the direction of this energy flow using the right hand rule. Around the battery, for example, the electric field is down and the magnetic field is into the screen, so you find the energy flux is to the right, away from the battery..."

Practical engineer using classical electrodynamics tool: "Now, the problem here is... this is something he doesn't address in the video. He's talking about the Poynting vector going out from the wire. Now, this is the case when you have AC. You have a... this is electromagnetic radiation, right? This is what happens. This is a big part of practical electrical engineering: designing products so that we can mantain the electromagnetic energy in the field surrounding the wire. This is why we have transmission lines, and coaxial cables. This is why we have transmission line theory on PCBs for example. But at DC, and DC steady state which we're going to take a look at, the Poynting vector is actually back INTO the wire. It's not going out, there's no electromagnetic radiation at DC. that only happens at AC.
But at DC it's actually pointing in, it's not going out." (gestures in the opposite direction as that shown by Derek)

It seems to me that the practical engineer has said - by using your language when you debunk dodgy tech - bullshit.
The Poynting vector at DC is directed as Derek has shown because the battery is giving its energy to the rest of the circuit. Maybe that's the reason you are being put down as a dumb arse engineer.
And make no mistakes, there is no interpretation of energy flow, integral over closed surfaces, momentum of the Maxwell fluid to add another intepretation here: it's just a cross product. With the fields shown the Poynting vector is pointing away from the battery. And even if you consider resistive wires, that will make the Poynting vector slightly impinge in the wires - well, that happens at DC as well as at AC.

You made the same error Science Asylum did back in his original video on energy transfer. Both of you ended up quoting Feynman, IIRC. And my wild guess is that you saw that picture on Feynman that shows a piece of resistive wires at DC with the Poynting vector pointing radially in and assumed that is what happens with wires at DC. Am I wrong?

[Sredni]

Carpenter's theorem states that if Maxwell's equations are correct, then JV is a valid energy flow. And with JV, energy flows only in wires.

Yes, it actually flows in the upper wire.
No, in the lower wire
No, wait, half and half.
No, no, wait again... it's 5/8 in the upper one and 3/8 in the lower one.
Or, the other way around?

The phi J representation is subject to as many representations as the potential. We have already been over that, some five or six pages ago.

[rfeecs]

The core, represented largely by an equivalent surface current J, , has the effect of a flywheel, into which the primary injects and recovers momentum by the remote action effect of A. The electron stream in the secondary conveys energy into the load, which generates a p4/2 pressure in the winding, and hence controls the rate at which energy is extracted from the ‘fluid."

Hmm, what is this "remote action effect"? Does he just mean... field effect? But doesn't want to say fields?

I'm thinking he means retarded potential:
https://en.wikipedia.org/wiki/Retarded_potential

In electrodynamics, the retarded potentials are the electromagnetic potentials for the electromagnetic field generated by time-varying electric current or charge distributions in the past. The fields propagate at the speed of light c, so the delay of the fields connecting cause and effect at earlier and later times is an important factor: the signal takes a finite time to propagate from a point in the charge or current distribution (the point of cause) to another point in space (where the effect is measured), see figure below.

It is still fields propagating.

[Naej]

So, uh, what about photons?

From https://en.wikipedia.org/wiki/Photon:

To explain the photoelectric effect, Einstein introduced the idea that light itself is made of discrete units of energy.

Yet another tool to use in the right situation.

Photon are quantum mechanical, there is no photon in Maxwell's equations.
An emitting antenna consumes energy (radiation resistance), a receiving antenna gives energy (radiation resistance).

So, all I'm getting from his paper is that he doesn't give a damn what happens in the middle (and uses the ad hoc 'remote action effect' term) - all he cares about is the end result. How much power is delivered from source to load?

But, this interpretation seems to be insufficient to answer Derek's question about how long it takes for the bulb to receive energy in the transient period. The mechanism of EM interaction IS important to Derek's question (that EM energy can traverse empty space at speed c, and if so, how?) - otherwise you'd be led to the wrong answer.

Classically, it's all fields.

A charge here creates scalar (Lorenz) potential V everywhere.
A moving charge here creates vector (Lorenz) potential A everywhere.
Potentials propagate at the speed of light, and this gives the answer: when you close the switch an EM disturbance is created, it propagates to the light and "switch it on".

(It's all fields until you remove them. See Liénard-Wiechert potential, for example in an Atoms & Sporks video or in Wiki)

If there is no energy in light - then what is radiation pressure?

Potential momentum qA being increased/decreased (remember that Lorenz' A propagates at the speed of light), and converted in a mechanical one.
So yes Carpenter's energy of light is 0, Carpenter's momentum of light is 0. It's vacuum after all! Why would you put energy in vacuum!   

Carpenter's theorem states that if Maxwell's equations are correct, then JV is a valid energy flow. And with JV, energy flows only in wires.

Yes, it actually flows in the upper wire.
No, in the lower wire
No, wait, half and half.
No, no, wait again... it's 5/8 in the upper one and 3/8 in the lower one.
Or, the other way around?

The phi J representation is subject to as many representations as the potential. We have already been over that, some five or six pages ago.

Yes all this are valid power flows. So it should start by yes or you are just making a controversy where there shouldn't be one.
I know it has been discussed, and also that if you accept JV then light has no energy …
But now you know that JV is correct  and your choice is essentially between "no energy in wires" and "no energy in light". Or "energy in wires" and "energy in light".

[rfeecs]

If there is no energy in light - then what is radiation pressure?

Feynman has an explanation for radiation pressure just from the fields acting on the charges:  https://www.feynmanlectures.caltech.edu/I_34.html

34–9   The momentum of light
Now we turn to a different topic. We have never, in all our discussion of the past few chapters, said anything about the effects of the magnetic field that is associated with light. Ordinarily, the effects of the magnetic field are very small, but there is one interesting and important effect which is a consequence of the magnetic field. Suppose that light is coming from a source and is acting on a charge and driving that charge up and down. We will suppose that the electric field is in the x-direction, so the motion of the charge is also in the x-direction: it has a position x and a velocity v, as shown in Fig. 34–13. The magnetic field is at right angles to the electric field. Now as the electric field acts on the charge and moves it up and down, what does the magnetic field do? The magnetic field acts on the charge (say an electron) only when it is moving; but the electron is moving, it is driven by the electric field, so the two of them work together: While the thing is going up and down it has a velocity and there is a force on it, B times v times q; but in which direction is this force? It is in the direction of the propagation of light. Therefore, when light is shining on a charge and it is oscillating in response to that light, there is a driving force in the direction of the light beam. This is called radiation pressure or light pressure.

[adx]

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.

If physics is stuck, then what else is left other than vagueness and a philosophical approach?

[HuronKing]

A charge here creates scalar (Lorenz) potential V everywhere.
A moving charge here creates vector (Lorenz) potential A everywhere.
Potentials propagate at the speed of light, and this gives the answer: when you close the switch an EM disturbance is created, it propagates to the light and "switch it on".

(It's all fields until you remove them. See Liénard-Wiechert potential, for example in an Atoms & Sporks video or in Wiki)

Maybe I'm an idiot but I really don't see how this interpretation removes any of the fields. And I looked at the Liénard-Wiechert potential - it's defined in terms of vector fields. We're still talking about the propagations of fields, through empty space.

Potential momentum qA being increased/decreased (remember that Lorenz' A propagates at the speed of light), and converted in a mechanical one.
So yes Carpenter's energy of light is 0, Carpenter's momentum of light is 0. It's vacuum after all! Why would you put energy in vacuum!   

Because since the 19th century we know that thermal energy can cross a vacuum? We've abandoned their aether interpretations of this, but, if the vacuum doesn't have energy, I'd be curious to know how you explain the Casimir Effect.

@rfeecs

Yes, I'm aware of Feynman's explanation of radiation pressure - that's why I question the statements Naej is making in their interpretation of Carpenter. After all, Feynman remarks a moment later,

Therefore the force, the “pushing momentum,” that is delivered per second by the light, is equal to 1/c times the energy absorbed from the light per second! That is a general rule, since we did not say how strong the oscillator was, or whether some of the charges cancel out. In any circumstance where light is being absorbed, there is a pressure. The momentum that the light delivers is always equal to the energy that is absorbed, divided by c:
⟨F⟩=dW/dtc.(34.24)
That light carries energy we already know. We now understand that it also carries momentum, and further, that the momentum carried is always 1/c times the energy.

[SiliconWizard]

The Casimir effect is a pretty peculiar beast. =)
But one thing to consider is that vacuum is not void.

[HuronKing]

The Casimir effect is a pretty peculiar beast. =)
But one thing to consider is that vacuum is not void.

Indeed. And I don't mean to be unfair by bringing it up. The Casimir Effect is not something predicted by Classical ED even if it has thematic similarities to aether ideas from Maxwell. I guess it just shows they had a shadow of vision of the future.

What I'm driving at is that in neither Classical ED, nor Einsteinian QM, nor in modern QFT is the vacuum considered to be a void that can't have energy in it. Thus, I don't really respond to philosophical arguments that suppose the vacuum can't have energy going through it 'just because' - whether it's energy-less photons or these "signals" (as Atom & Sporks says in the video recommended video by Naej) from one charge to another that are very totally not energy propagating in a field, just, 'remote action effects.' 

[eti]

I'm always VERRRRRRRRY skeptical of anyone who uses transparent, clickbaity hyperbole such as prepending the title with ✌️"The big..."✌️

I automatically think "if it's that big, people will know it instinctively, ergo your emphasising this is redundant, or merely for likes and subs" (sadly nearly ALWAYS the case, no matter who they are, or how "reputable".

It's sad, and somewhat amusing to me that supposedly intelligent people on YouTube, nearly ALL seem to fall into that trap.

[bsfeechannel]

Carpenter's theorem states that if Maxwell's equations are correct, then JV is a valid energy flow. And with JV, energy flows only in wires.

So either:
a) you find a flaw in the 3 lines proof of the theorem
b) you find a counter-example to the theorem
c) you compare Maxwell's equations to flat earth-theory.

No, thanks. Won't waste my time with a stillborn scientific paradigm rejected early on by Maxwell for very good reasons.

Conclusion: the statement "energy flows only in wires" is correct.

What you're doing is the same thing you're accusing Derek of having done. If the energy flows ONLY in the wires, the other theories are wrong.

Dave: could you transmit the first message to Derek please?

You've already had your 15 minutes of fame.

[EEVblog]

I'm always VERRRRRRRRY skeptical of anyone who uses transparent, clickbaity hyperbole such as prepending the title with ✌️"The big..."✌️

I automatically think "if it's that big, people will know it instinctively, ergo your emphasising this is redundant, or merely for likes and subs" (sadly nearly ALWAYS the case, no matter who they are, or how "reputable".

It's sad, and somewhat amusing to me that supposedly intelligent people on YouTube, nearly ALL seem to fall into that trap.

Derek has done an an entire video on how he is deliberately chasing the algorithm and views. he's quite up front about it and explains his reasons at 14:45 and I think they are solid. And I know he's genuine about wanting to get mainstream people into science.

[adx]

Conclusion: the statement "energy flows only in wires" is correct.

What you're doing is the same thing you're accusing Derek of having done. If the energy flows ONLY in the wires, the other theories are wrong.

I used to play chess. Wasn't awfully good at it, but good enough to see what just happened there.

[adx]

Got it.

The Veritasium circuit (the one with the LED filament lamp, the plain DC or 50 / 60Hz one) is a transmission line. It gets 'loaded up' with a DC pulse at the rate of V^2/Z per light-second of line. All of this energy passes through all the Ls and Cs at the speed of light. Therefore all of the energy delivered to an impedance matched load travels via the fields.

How I came up with this insight: I was reading Sredni's post[1] properly with a view to a quick reply. But the conundrum I've addressed before came up: While a relatively small amount of energy is stored in the L and C of the wire, the bulk of the energy seems to be sucked by the resistor which creates (wrong word) a voltage drop at the end of the line (establishing a (longitudinal) pressure gradient all down the circuit, and same current, so it 'enjoys' the largest pressure drop but mostly nothing to do with the mechanical topology of the circuit). It seemed implausible that such a small amount of energy stored in the fields could be totally responsible for the power flow. Then I saw my mistake: The energy flows at the speed of light in electrical circuits, I was thinking more of charge carriers (in my defence also correct as power = force * velocity). Interesting but hardly a new revelation. Until I was having a chomp on some cheese a little later, and thought about my earlier post[2] about transmission lines and how they are charged with a moving but DC wave (and I meant perfectly DC, not the intentionally mixed metaphor above). I thought that seemed usefully convincing. It also helps place this "energy is in the fields" concept more firmly in the context of waves than mechanical flow. I assume it would be the same for a hydraulic circuit - if interested in how much energy is carried by an acoustic wavefront (pulse), you're not going to use the material flow rate in the calculation. Waves are strange.

Note I'm not trying to say or prove energy is actually in the fields. It is just a piece of the conceptual puzzle my brain needed to accept the Poynting vector is not a complete physical nonsense. If the kernel of my insight isn't clear enough (it's bordering on fading away already), it is that a transmission line is filled with energy, that is the energy's only purpose from when it goes in to when it comes out. Even if DC.

Also better say I use the terms "energy" and "speed of light" somewhat metaphorically.

Links more conveniently out of the way:
1. https://www.eevblog.com/forum/chat/veritasium-(yt)-the-big-misconception-about-electricity/msg3935938/#msg3935938
2. https://www.eevblog.com/forum/chat/veritasium-(yt)-the-big-misconception-about-electricity/msg3895310/#msg3895310

[Naej]

A charge here creates scalar (Lorenz) potential V everywhere.
A moving charge here creates vector (Lorenz) potential A everywhere.
Potentials propagate at the speed of light, and this gives the answer: when you close the switch an EM disturbance is created, it propagates to the light and "switch it on".

(It's all fields until you remove them. See Liénard-Wiechert potential, for example in an Atoms & Sporks video or in Wiki)

Maybe I'm an idiot but I really don't see how this interpretation removes any of the fields. And I looked at the Liénard-Wiechert potential - it's defined in terms of vector fields. We're still talking about the propagations of fields, through empty space.

Depends what you mean by fields, when people say "energy is in the fields" they mean in fact "energy is in vacuum", and with Carpenter's interpretation, V,A are mathematical fields but vacuum plays no role at all, it's just the place where they propagate.

Liénard-Wiechert showed that you could completely remove them. In Wiki the formulas give the potentials produced, because everyone thinks in terms of potentials/E,B, but you can just compute the forces exerted on particles by each other in this way and stop here.
In this way, you get the dynamic version of Coulomb force (which is equivalent to Maxwell's equation), and where vacuum plays absolutely no role (except retarding forces), there is no need to define a potential in vacuum.
If you take this to be "the truth" then the concept of light is this: accelerated charges create forces on charges which slowly decrease with distance.

The Casimir effect is a pretty peculiar beast. =)
But one thing to consider is that vacuum is not void.

Indeed. And I don't mean to be unfair by bringing it up. The Casimir Effect is not something predicted by Classical ED even if it has thematic similarities to aether ideas from Maxwell. I guess it just shows they had a shadow of vision of the future.

What I'm driving at is that in neither Classical ED, nor Einsteinian QM, nor in modern QFT is the vacuum considered to be a void that can't have energy in it. Thus, I don't really respond to philosophical arguments that suppose the vacuum can't have energy going through it 'just because' - whether it's energy-less photons or these "signals" (as Atom & Sporks says in the video recommended video by Naej) from one charge to another that are very totally not energy propagating in a field, just, 'remote action effects.' 

The concepts have to change with the theory you use, and the theory with what you're doing.
If you want the current conception of vacuum, then it's a (local?) minimum of energy, whose energy (named dark energy) is driving an exponential-like acceleration of the size of the universe. And Casimir effect is because you can go below the vacuum in energy density.
If it's only a local minimum then it can decay, and it's one popular theory of what happened at the initiation of the Big Bang.

bsfeechannel: so you reject a theorem with 19th century philosophy. Ok. 
Also I said many times that both Poynting's and Carpenter's view are correct, so if you don't see a difference with what Derek said, then you don't see much.

adx: if you follow Poynting then copper wires are the low-frequency equivalent of light fiber, a transformer is impedance matching, and a resistor is a low-frequency black-body.
For acoustic waves, half the energy is in the pressure, and half in the velocity (much like in light, half is in E, half is in B).

[rfeecs]

Yes, I'm aware of Feynman's explanation of radiation pressure - that's why I question the statements Naej is making in their interpretation of Carpenter. After all, Feynman remarks a moment later,

Therefore the force, the “pushing momentum,” that is delivered per second by the light, is equal to 1/c times the energy absorbed from the light per second! That is a general rule, since we did not say how strong the oscillator was, or whether some of the charges cancel out. In any circumstance where light is being absorbed, there is a pressure. The momentum that the light delivers is always equal to the energy that is absorbed, divided by c:
⟨F⟩=dW/dtc.(34.24)
That light carries energy we already know. We now understand that it also carries momentum, and further, that the momentum carried is always 1/c times the energy.

Carpenter denies there is any experimental evidence that light carries momentum:

The most obvious is momentum. The idea of electromagnetic
radiation carrying with it a momentum, and
hence exerting a force on any absorbing surface, epitomises
the properties which are customarily taken as
direct experimental evidence of the existence of the field.
But, as is well recognised [4-9], these properties are
unsupported by any evidence which is independent of the
way in which they are defined.

I'm not buying it.  I suppose he means that the way he defines things, it is charges acting on each other at a distance rather than fields acting on particles.

This would require reformulating lots of physics since Maxwell.

[ogden]

That is because " Engineers are essentially dumbed-down "physicists". "

LOL Quite accurate. Engineers are taught to be effective - to *not* dig into deep details of underlying physics and calculations as long as simplified model gives results within target tolerance.

TLDR, sorry. I wonder - it was mentioned or not that such kind of transmission lines (twin-lead) are lossy? They radiate energy away as EM waves disregarding zero conduction losses and being in vacuum. It means that lamp may go off after initially lit, to wait for DC conduction to kick-in.