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| Veritasium "How Electricity Actually Works" |
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| hamster_nz:
--- Quote from: electrodacus on May 12, 2022, 04:16:41 am --- --- Quote from: hamster_nz on May 12, 2022, 04:01:16 am ---And yet without picking an arbitrary external reference you are unable to point to show one measurable difference between a wire that is carrying 0.1V @ 1mA and the same type of wire carrying 100V @ 1mA. They even have the same (minimal) internal resistive heating. They have the same magnetic field around them. They have the same voltage drop from end to end. And that is with an energy difference of three orders of magnitude... that is pretty strong evidence. If you have to use an external reference, that is a pretty strong indicator that is is where it is in space that matters - that where it is in the electric field defines the energy. --- End quote --- You will have a different circuit at least a different lamp if you want your circuit to use 1mA. At 0.1V for the voltage source the lamp resistance including the likely negligible wire resistance will need to be 100Ohm so that current is 1mA At 100V the lamp will need to be 100kOhm to get that same 1mA. So circuit will be very different but wires have resistance to current flow the voltage is irrelevant other than wire isolation or separation in air between wires. So the difference is the lamp that is also a wire if we are talking about an incandescent lamp. First lamp will be 0.1mW while second lamp will be 0.1W. If you keep the same wires the voltage drop across the wires will be the same since current is the same thus energy loss on the wire will be the same. So I have no idea what you want to prove with this example. --- End quote --- And you are not bothered that the energy lost in the wire is identical, even though it carries vastly different levels of power (1000x)? The energy loss in the wire changes with the current being transferred, not the energy being transferred. To me that strongly suggests that the wires are transferring current, not energy. |
| bsfeechannel:
--- Quote from: HuronKing on May 09, 2022, 08:35:25 pm ---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 --- Science is counterintuitive in essence. Galileo had trouble explaining that the earth spins on its axis. If you ride a fast horse you experience wind against your face. If the earth spins so fast, why don't we see a huge gale sweeping the earth? Einstein's theories, although very successful are the target of active attempts at proving them wrong. The job of science is to provide the most probable explanations due to the inductive (in the logical sense) nature of its reasoning. But some people expect the truth from science. Since theories present the most probable explanation, not the "correct", they give the opportunity for trying to find alternatives. Those who expect truth form science, not knowledge, are led to think that the theories are unsound and that there must be some kind of conspiracy to hold them in high regard. |
| electrodacus:
--- Quote from: hamster_nz on May 12, 2022, 04:37:42 am --- And you are not bothered that the energy lost in the wire is identical, even though it carries vastly different levels of power (1000x)? The energy loss in the wire changes with the current being transferred, not the energy being transferred. To me that strongly suggests that the wires are transferring current, not energy. --- End quote --- Why will I be bothered by that ? Seems very normal to me. Current * resistance gets you the voltage drop. If you are using the same wires in both examples and current is the same then voltage drop across the wire is the same and thus power loss on the wire is the current multiplied by the voltage drop across the wire. The energy travels through wire and transportation losses are the same. The energy will be delivered to a different lamp so you do not have the same lamp in the two examples (your setup). The lamp is also a wire and on that wire voltage drop will be very different between the two examples. So that wire (the lamp filament) will have much more energy converted to infrared and visible light in the second example than the first. There is nothing in your examples to show energy is not traveling through wires. You have the two low resistance wires on each side of the bulb having the same loss in both cases to transfer the energy to the third wire with is the lamp filament. The difference is in the lamp filament between the two cases and that is where the electrical energy will do the most work. |
| SandyCox:
--- Quote from: EEVblog on May 12, 2022, 02:30:49 am --- --- Quote from: IanB on May 11, 2022, 07:18:57 pm --- --- Quote from: electrodacus on May 11, 2022, 06:55:56 pm ---You have a wrong understanding of what energy is and how it is transferred from source(battery) to load (lamp/resistor). --- End quote --- If on the one side we have electrodacus, who is right, and on the other side we have the rest of the world, who are wrong, then really all rational people would wish to be with the rest of the world and remain wrong. Apparently, in this scenario, being wrong is the right place to be. --- End quote --- The other big thread used to be filled with the Maxwell/Poynting Bro's absolutely shooting down anyone who dared even hinted at suggesting anything other than a 100% Poynting explanation, and heaven forbid if you got even even the slightest direction of Poynting vector wrong, it's was flaming pitchforks. Now all the Poynting bros have vanished and both threads are now completely dominated by the Energy In The Wire (EIT) absolutists. LOL :-DD :popcorn: --- End quote --- People should focus on what Poynting's theorem says and not read extra meaning into it. You have to integrate the Poynting vector over the surface off a volume enclosing a region in space. Other than that, it doesn't have physical meaning. Don't let the pretty pictures distract you. |
| hamster_nz:
--- Quote from: electrodacus on May 12, 2022, 05:27:08 am ---Why will I be bothered by that ? --- End quote --- And it doesn't bother you at all that there is no circuit you can put in region A in the diagram below that can extract energy from the wires that surround it? Even a DC/DC convertor? Even if you can connect it to a GND? But extracting energy from regions B or C is a piece of cake? And I guess that it doesn't bother you if an isolated charge is placed in region A and it stays where it is put, but if the same charge is placed in B or C it will accelerate, acquiring energy ultimately suppled from the battery, without being connected to it? And it doesn't both you if you charge a capacitor between +110V and +100V is has exactly the same stored energy as one charged between 0V and -10V? Even though one has been charged at a higher energy? And the other has been charged at a completely different polarity? And it doesn't bother you that a transformer can get 95%+ transfer of energy from one wire to the other, even though the wires don't touch, and no charges from the input wire get transferred to the output wire? And it doesn't bother you that for your version of electrostatics (sum of force between charges), every charge needs to be in consistent communication with every other charge in the universe, to work out how far away they are, and at what direction? And it doesn't bother you that a transmission line is a series of inductors and capacitors, however on inspection those capacitors and inductors can neither be identified or isolated? And it doesn't bother you that commercial radio transmitters can get kilowatts of energy to disappear into literally thin air? You must be a firm believer in the Lumped Element Model. It seems to work, so to you it must reflect the mechanics of reality, rather than an useful abstraction and approximation that allows you to get stuff done. |
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