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Veritasium "How Electricity Actually Works"

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bsfeechannel:

--- Quote from: Naej on May 09, 2022, 07:14:26 pm ---Why can't I find them in all modern books: Jackson, Griffiths, Haus Melcher and so on?

--- End quote ---

Maybe you're functionally illiterate, who knows?

HuronKing:

--- Quote from: bsfeechannel on May 09, 2022, 07:27:18 pm ---
--- Quote from: Naej on May 09, 2022, 07:14:26 pm ---Why can't I find them in all modern books: Jackson, Griffiths, Haus Melcher and so on?

--- End quote ---

Maybe you're functionally illiterate, who knows?

--- End quote ---

Worth a read:
https://royalsocietypublishing.org/doi/10.1098/rsta.2017.0457#RSTA20170457C39


--- Quote ---One problem that Heaviside used to illustrate the energy current concept was that of a battery connected by a simple circuit to a resistor load in his 1886–1887 work ‘The transfer of energy and its application to wires. Energy current’ [33]—effectively an analysis of a ‘twin wire transmission line’. The standard approach is to assume that electrical energy flows inside metal wires (confinement), but Heaviside's energy current approach dictates otherwise. Poynting had first published on this arrangement [31], which was criticized by Heaviside due to Poynting's misconception of the nature of the external electric field surrounding the wires [32,34]. Poynting considered only a tangential electric field in the axis of the wire, combined with the circumferential magnetic field, resulting in an inwardly radial component of the energy flux density, W, only. Thus, given no energy flux in the direction of the electric current—how does energy get from the battery to the load? This is not answered by conventional circuit theory. Heaviside argued that this ‘Poynting component’ is simply the heat lost due to Joule heating in the conductor; however, a more prominent component exists outside the wire due to a radial electric field—the surface charges on the conductors that set up the field and maintain the electric current are responsible for the energy transfer external to the conductors. This complete field picture then presents a ‘map’ of the energy flow. Heaviside showed for the first time that a radial electric field and a circumferential magnetic field produce an ‘energy current’, a flow of electromagnetic energy in the space surrounding the electric conductors, directed from the battery along the axis of the conductor towards and entering the load.
--- End quote ---


--- Quote ---This remarkable result is one that is rarely presented, but that Heaviside gives in great detail in his Electrical papers, vol. II, which have recently been the subject of a rigorous modern mathematical treatment [39], confirming Heaviside's results. It is readily shown that the energy current approach is compatible with the circuit theory approach by applying the integral formulation of the Poynting theorem to the problem, determining the power dissipated in the load resistor as VI, as dictated by conventional ‘confined’ circuit theory. This ‘energy current approach’ gives physical insight, but requires detailed knowledge of the electric and magnetic fields surrounding the analysed circuits. It complements his work on electromagnetic wave propagation by analysing the energy associated with the wave and also his work on electromagnetic diffusion in which he found that the current in the wire penetrates from the outside surface inwards.
--- End quote ---

Earlier in the article, the controversy is addressed head on. Even more than 140+ years later, Heaviside is still stirring the pot:

--- Quote ---It is well known that this approach is useful in antenna theory and microwave circuits. However, Heaviside extended the use of the theorem to DC electric circuits. In doing so, he reversed the contemporary view of electric current, proposing that the electric and magnetic fields due to the current are the primitives, rather than being a result of the motion of the electronic charge in the conductor. This is a controversial viewpoint and, in his Electrical papers, the phrase ‘we reverse this’ [36], referring to the ‘current in the wire being set up by the energy transmitted through the medium around it’, reverberates even to this day. This view is supported by his work on electromagnetic diffusion (previous section) and the nature of the electromagnetic field and current density penetration of an electrical conductor subjected to a step current. This is discussed in a modern context by Feynman [37], who showed that the electromagnetic momentum is ‘required’ in order to conserve angular mechanical momentum associated with the energy flux vector W, and a detailed historical discussion is presented by Nahin [12]. The ‘uniqueness’ of the vector W and the physical existence of mysterious and counterintuitive circulating ‘energy currents’ emerging from static fields (e.g. a point electric charge with a superimposed magnetic dipole) has been the subject of some debate among many scientists over a long period of time. Heaviside was the first to consider these issues in 1893 [38].
--- End quote ---

HuronKing:
EEVBlog drew attention to this in his original response video to Veritasium but it's worth bringing up again, especially since Feynman gets a shout-out from the Royal Society:
https://www.feynmanlectures.caltech.edu/II_27.html


--- Quote ---But it [eq.27.20] tells us a peculiar thing: that when we are charging a capacitor, the energy is not coming down the wires; it is coming in through the edges of the gap. That’s what this theory says!
--- End quote ---

And of course Feynman has this to say (which Dave also drew attention to):

--- Quote ---You no doubt begin to get the impression that the Poynting theory at least partially violates your intuition as to where energy is located in an electromagnetic field. You might believe that you must revamp all your intuitions, and, therefore have a lot of things to study here. But it seems really not necessary. You don’t need to feel that you will be in great trouble if you forget once in a while that the energy in a wire is flowing into the wire from the outside, rather than along the wire. It seems to be only rarely of value, when using the idea of energy conservation, to notice in detail what path the energy is taking. The circulation of energy around a magnet and a charge seems, in most circumstances, to be quite unimportant. It is not a vital detail, but it is clear that our ordinary intuitions are quite wrong.
--- End quote ---

Perhaps its possible to ignore all this business and retreat back to the hydraulic arguments about electrons being like water in pipes. Hayt concedes it might just be a philosophical problem - but yet he takes a firm position on which interpretation he prefers. So did Heaviside. So did Kraus. And even Feynman to an extent. He was lecturing to a room of freshmen/sophomore physics students in the 1960s. If he were talking to a room of engineers designing waveguides, the emphasis would be very different.

Our intuition is wrong - and these properties of fields are important if we think Maxwellian Theory means anything.

PlainName:

--- Quote from: electrodacus on May 09, 2022, 06:17:58 pm ---I think that is a fantastic video and unless you do not agree that is what happens there it debunks Derek's claim that energy travels outside the wire in his experiment.

--- End quote ---

Remind me, who was it that said:


--- Quote ---Internet is also fool of java type animations and explanations of capacitors and most of them are incorrectly made as the author did not understand the physics and made wrong assumptions.
--- End quote ---

Naej:

--- Quote from: HuronKing on May 09, 2022, 08:35:25 pm ---EEVBlog drew attention to this in his original response video to Veritasium but it's worth bringing up again, especially since Feynman gets a shout-out from the Royal Society:
https://www.feynmanlectures.caltech.edu/II_27.html


--- Quote ---But it [eq.27.20] tells us a peculiar thing: that when we are charging a capacitor, the energy is not coming down the wires; it is coming in through the edges of the gap. That’s what this theory says!
--- End quote ---

And of course Feynman has this to say (which Dave also drew attention to):

--- Quote ---You no doubt begin to get the impression that the Poynting theory at least partially violates your intuition as to where energy is located in an electromagnetic field. You might believe that you must revamp all your intuitions, and, therefore have a lot of things to study here. But it seems really not necessary. You don’t need to feel that you will be in great trouble if you forget once in a while that the energy in a wire is flowing into the wire from the outside, rather than along the wire. It seems to be only rarely of value, when using the idea of energy conservation, to notice in detail what path the energy is taking. The circulation of energy around a magnet and a charge seems, in most circumstances, to be quite unimportant. It is not a vital detail, but it is clear that our ordinary intuitions are quite wrong.
--- End quote ---

Perhaps its possible to ignore all this business and retreat back to the hydraulic arguments about electrons being like water in pipes. Hayt concedes it might just be a philosophical problem - but yet he takes a firm position on which interpretation he prefers. So did Heaviside. So did Kraus. And even Feynman to an extent. He was lecturing to a room of freshmen/sophomore physics students in the 1960s. If he were talking to a room of engineers designing waveguides, the emphasis would be very different.

Our intuition is wrong - and these properties of fields are important if we think Maxwellian Theory means anything.

--- End quote ---
You found some nice quotes like:

--- Quote ---But it [eq.27.20] tells us a peculiar thing: that when we are charging a capacitor, the energy is not coming down the wires; it is coming in through the edges of the gap. That’s what this theory says!
--- End quote ---

--- Quote ---The standard approach is to assume that electrical energy flows inside metal wires (confinement), but Heaviside's energy current approach dictates otherwise.

--- End quote ---
which explains clearly that it is a theory dictating where energy flows, not experiments.
Much like bsfeechannel, they don't point to experiments, because they cannot.
And here:

--- Quote ---You no doubt begin to get the impression that the Poynting theory at least partially violates your intuition as to where energy is located in an electromagnetic field. You might believe that you must revamp all your intuitions, and, therefore have a lot of things to study here. But it seems really not necessary. You don’t need to feel that you will be in great trouble if you forget once in a while that the energy in a wire is flowing into the wire from the outside, rather than along the wire. It seems to be only rarely of value, when using the idea of energy conservation, to notice in detail what path the energy is taking. The circulation of energy around a magnet and a charge seems, in most circumstances, to be quite unimportant. It is not a vital detail, but it is clear that our ordinary intuitions are quite wrong.
--- End quote ---
You can see that intuitions being "wrong" is not justified by experiments, it's just that it just intuition is not what Poynting's theory tells:

--- Quote ---    But it [eq.27.20] tells us a peculiar thing: that when we are charging a capacitor, the energy is not coming down the wires; it is coming in through the edges of the gap. That’s what this theory says!

--- End quote ---
Much like "siemens" is not the wrong version of "mho" (even when Thomson himself used mho), "energy flows through wires" is not the wrong version of "energy flows through vacuum".

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