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| Veritasium "How Electricity Actually Works" |
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| electrodacus:
--- Quote from: hamster_nz on May 23, 2022, 09:01:58 pm --- I was pointing out a system where a vacuum tank and pipes can deliver energy to an air-powered tool, using the air outside of the hose, by literally delivering nothing in the pipes. You just don't like it because the open air molecules have no 'special' added energy, and they also have no 'special' added energy when in the vacuum pipes on the way back to the tank & pump, pipes are required, those pipes are empty, and yet somehow still deliver energy to the tool. --- End quote --- All analogies have limitations and if I used an analogy then it was used to explain just a single aspect and you can not go with the analogy further. That vacuum pipe will carry air molecules that are taken from ambient so you just reversed where the source of air particle is the polarity. There is a delta in pressure between the vacuum (absence of air molecules) and ambient. So you vacuum cylinder will be filled with air molecules at same concentration as ambient when all energy is used up. The vacuum analogy is not great for a capacitor as you can never remove all electrons from a plate not even close. So your empty pipe is no longer empty when it delivers energy. |
| SiliconWizard:
--- Quote from: HuronKing on May 23, 2022, 05:34:38 pm --- --- Quote from: SiliconWizard on May 23, 2022, 05:13:13 pm ---It's been two threads and things are still running in circles. While I do not agree with everything electrodacus has written, I understand his question here: I don't think I've really seen a proper answer (except possibly in the early stages of the first thread), neither on here or in Veritasium's videos, about the role of wires and why we actually needed them (but we do for sure.) --- End quote --- Wires are wave guides. Fields emanate from charges - charges live in conductors and the field disturbances carry the energy which influences nearby charges or charges in other conductors. I posted a video a few replies ago that illustrates this. And Kraus in Chapter 10 makes this explicit when he describes the Poynting Vector in circuit theory terms in a chapter about wave guides (including showing what happens when an infinite conducting sheet is placed between battery and load and how this changes the shape of the Poynting vector field). And Feynman includes a lecture on this: https://www.feynmanlectures.caltech.edu/II_24.html --- End quote --- IIRC, I did post a link to this very lecture quite a while ago. I suggest anyone not fricking tired of it already to go read the 80 pages of the other thread and then this one just to 1/ learn a few things and 2/ realize how this has been running in circles for ages now. I'm sure it can keep going almost forever though. It's almost as though perpetual motion has finally been resolved. --- Quote from: rfeecs on May 23, 2022, 06:11:18 pm ---For a wire carrying a DC current it's a slightly different story. --- End quote --- It is, and as we discussed a long time ago already, the unfortunate part of the whole Veritasium example (not the theory itself) is that the transient phenomenon upon closing the switch and the operation at steady state have been blurred somewhat. I don't think this point has been fully addressed in the second video. But the problem is that having a transient phase is the only straightforward way of making the point. *Insert coin* |
| electrodacus:
--- Quote from: SiliconWizard on May 23, 2022, 09:30:14 pm ---It is, and as we discussed a long time ago already, the unfortunate part of the whole Veritasium example (not the theory itself) is that the transient phenomenon upon closing the switch and the operation at steady state have been blurred somewhat. I don't think this point has been fully addressed in the second video. But the problem is that having a transient phase is the only straightforward way of making the point. *Insert coin* --- End quote --- The claim Derek (Veritasium) made that "energy doesn't travel through wires" is more than ridiculous. His so called "evidence" was to show that some energy arrives at the lamp before the electron wave has the time to travel the entire wire distance. For anyone that properly understand what a capacitor is the obvious answer to that small amount energy that arrives earlier is the loss in wires/lamp while charging that capacitance and it is accurately described and calculated by the lumped model. You can get rid of this capacitance charging through the lamp by shielding just one side of the circuit bypassing the lamp then it can be seen that no energy arrives at the lamp before the electron wave gets there. This will show that capacitance charging is what produces an electron flow through the lamp and also shows that energy is delivered through wires else no energy could arrive at the lamp as it is shielded from electric field. I need to apologise for being a bit rude in some of my replayes as most of you rely on you learned from others and unfortunately the way this is teached in schools is not up to current understanding. I do not think it is OK for Maxwell to still be relevant when at his time the structure of the atom was not discovered. Yes the equations still work but the conclusions that can be drawn from them can be very misleading. To be fair to schools I do not think any engineering school teaches that energy travels outside the wires but it also not makes that clear enough so that a youtube celebrity can not convince them the opposite is true. |
| PlainName:
--- Quote ---You can get rid of this capacitance charging through the lamp by shielding just one side of the circuit bypassing the lamp then it can be seen that no energy arrives at the lamp before the electron wave gets there. --- End quote --- You mean "then it should show". Unless you've actually done this then it is supposition, but you continue to pretend things like this are fact. That's one of the things that rubs people up the wrong way. |
| snarkysparky:
""It can not follow from what I wrote as I never wrote that energy flows through a capacitor but energy flows in or out of a capacitor."" So can energy both flow in and out of a capacitor at the same time ? |
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