Veritasium "How Electricity Actually Works"

[aetherist]

Two words:  quantum mechanics.

So, free photons, emitted by atoms of gas excited by electricity in a laser, act like light etc.
And free photons emitted by a very hot glowing wire act like light etc.
And, free photons emitted by electricity in or on a wire act like charge and/or like magnets.
So, free photons can have say 3 states (light charge magnetism). And QM explains.

Question. Why cant free photons have these 3 states at the same time, ie a mixture?
Or light & charge at the same time.
Or light & magnetism at the same time.
Or charge & magnetism at the same time.
Thats a total of 7 combinations.
Dont tell me, let me guess, the probability of some of these is zero all of the time.

[hamster_nz]

Ah and of course, you say that 'energy is in electron' is false, but with no experimental evidence; so it's your opinion, not a fact.

 I charge two capacitors in series, to 10V (so 5V in each). While the power is still on I remove them, and put them on the bench.

They still have charge in them.

How can you tell which one was connected to 10V, and which was connected to 0V

[electrodacus]

Here even more proof energy travels through wire's and not outside the wire in Derek's example.  No that there is any evidence to the contrary but maybe one of them will make you understand this is the reality in this universe.

Same LTspice transmission line simulation was used but I have used two examples.

First one is with Switched turned ON and staying ON and the second with switched turned ON for just 30ns so it was switched off before electrons got to the lamp/resistor.

The graphs show power leaving the source and the power on the resistor/lamp. The resistor is 1KOhm and the transmission line has 20Ohm resistance so there are some losses as energy travels through the wire.



This is for switch staying ON. The energy is the area under the power graph and over the 400ns 155.05nJ where delivered by the source while at the lamp/resistor 142.1nJ in the same period



This is for the switch being turned OFF (open circuit) after 30ns. In this case just 9.16nJ left the source and 7.68nJ where delivered to the lamp/resistor most of witch after the switch was OFF so open circuit.


I think at least two things are very clear from this graphs.
There is energy storage involved and energy travel through wire with the missing energy being dissipated as heat on the transmission wire. 

[T3sl4co1l]

So you're telling me wires are made of shittons of inductors and capacitors, through which the power flows, and that those inductors and capacitors -- you know, the in-circuit manifestations of fields in space -- are somehow hidden away, packed up inside a tiny hunk of metal?

Tim

[SandyCox]

Here even more proof energy travels through wire's and not outside the wire in Derek's example.  No that there is any evidence to the contrary but maybe one of them will make you understand this is the reality in this universe.

How does sunlight get to the earth? Do you see wires connected between the sun and the earth?

[snarkysparky]

Does electricity flow in air or wires?

The correct answer is BOTH..

In the video a transient energy lights the bulb quickly because of fields.  But the wires take over, otherwise there could be no light output from a DC source.

It seems this whole confusion is cause by the attempt to make it one or the other.

[SandyCox]

I agree.

[PlainName]

In the video a transient energy lights the bulb quickly because of fields.  But the wires take over, otherwise there could be no light output from a DC source.

It seems this whole confusion is cause by the attempt to make it one or the other.

I think that's missing an important thing. No doubt we are all mostly agreed that there is some fields stuff going on before the wires are connected, but what it's really about is after that, when there is a solid wired connection. Does the energy flow in the wire, on the wire (skin) or is the wire merely a guide and the energy actually flows still in the field? As I see it, and it's sometimes tricky to remember what the argument is about, it's that last option which is the crux of the video and this discussion.

[EEVblog]

Does electricity flow in air or wires?

The correct answer is BOTH..

In the video a transient energy lights the bulb quickly because of fields.  But the wires take over, otherwise there could be no light output from a DC source.
It seems this whole confusion is cause by the attempt to make it one or the other.

The math works out for both DC and AC, and the claim is the same, the energy flow is outside/on the surface of the wire, even at DC. The entiriety of classical electrodynamics physics in built upon this.

[EEVblog]

I think that's missing an important thing. No doubt we are all mostly agreed that there is some fields stuff going on before the wires are connected, but what it's really about is after that, when there is a solid wired connection. Does the energy flow in the wire, on the wire (skin) or is the wire merely a guide and the energy actually flows still in the field? As I see it, and it's sometimes tricky to remember what the argument is about, it's that last option which is the crux of the video and this discussion.

For me the question is entirely about DC and energy inside vs outside the wire. Nothing to do with switches, transmission lines, capacitors, inductors, transformer theory, antenna theory etc etc.

[SandyCox]

I think that's missing an important thing. No doubt we are all mostly agreed that there is some fields stuff going on before the wires are connected, but what it's really about is after that, when there is a solid wired connection. Does the energy flow in the wire, on the wire (skin) or is the wire merely a guide and the energy actually flows still in the field? As I see it, and it's sometimes tricky to remember what the argument is about, it's that last option which is the crux of the video and this discussion.

For me the question is entirely about DC and energy inside vs outside the wire. Nothing to do with switches, transmission lines, capacitors, inductors, transformer theory, antenna theory etc etc.

Exactly!

I think that, under static conditions, all the energy is transferred by the electrons. They gain electrostatic potential energy as they move through the battery and loose electrostatic potential energy as they move through the lightbulb. The electron's electrostatic potential energy should not be confused with their kinetic energy.

[snarkysparky]

"The math works out for both DC and AC, and the claim is the same, the energy flow is outside/on the surface of the wire, even at DC. The entiriety of classical electrodynamics physics in built upon this."


But if you substituted the wires for tubes of the same diameter with copper outer shell of infinitesimal thickness the light bulb would not stay lit.   Some inner copper is required beyond just a shell covering.

[vad]

Hontas Farmer is back still saying the Derek is both right and wrong acording to QFT/QED

QED (as all other QFTs) is a perturbation theory that extends Classical Electrodynamics to a quantum scale. QED is by no means a more fundamental theory than Classical Electrodynamics, and as being the extension, QED cannot contradict Classical Electrodynamics at macroscopic level. https://arxiv.org/pdf/1201.5536.pdf

Because QED is the perturbation theory, its approximate mathematical framework quickly falls apart when trying to describe classical systems (systems with billions of photons, electrons), as discussed in this paper: http://old.cft.edu.pl/~birula/publ/ClassLimit.pdf

In other words, QED has it own domain, and Classical Electrodynamics has its own domain. These domains do not overlap. Within their respective domains each theory has been validated experimentally to a very high degree.

In other words, to describe energy transfer in macroscopic systems proposed in Veritasium experiments, the only scientific tool Physics has is Classical Electrodynamics, and it is accurate at given scales.

[vad]

For me the question is entirely about DC and energy inside vs outside the wire. Nothing to do with switches, transmission lines, capacitors, inductors, transformer theory, antenna theory etc etc.

The only EM energy that flows into the wires is the energy that cause wire heating. The rest of the EM energy flows outside the wires.

Here is a paper, where authors compute energy flows around cylindrical wire: http://sharif.edu/~aborji/25733/files/Energy%20flow%20from%20a%20battery%20to%20other%20circuit%20elements.pdf

[Naej]

Ah and of course, you say that 'energy is in electron' is false, but with no experimental evidence; so it's your opinion, not a fact.

 I charge two capacitors in series, to 10V (so 5V in each). While the power is still on I remove them, and put them on the bench.

They still have charge in them.

How can you tell which one was connected to 10V, and which was connected to 0V

Here is a funny exercise (not related to anything I said):
I charge 100 capacitors in series, to 1 MV.
While the power is still on I remove them, and put them on the bench.

They still have charge in them.

How can you tell which one was connected to 1MV, and which was connected to 0V?

If you're trying to say "all electrons are identical" then I agree.

[electrodacus]

So you're telling me wires are made of shittons of inductors and capacitors, through which the power flows, and that those inductors and capacitors -- you know, the in-circuit manifestations of fields in space -- are somehow hidden away, packed up inside a tiny hunk of metal?

Tim

That is exactly right. Also it happens that the simulation using this matches experimental results perfectly.

[electrodacus]

For me the question is entirely about DC and energy inside vs outside the wire. Nothing to do with switches, transmission lines, capacitors, inductors, transformer theory, antenna theory etc etc.

Energy flows inside the wire both for AC and DC. The difference is that with DC the energy flow is uniform inside the wire meaning the entire section of the wire is used while with AC the higher the frequency and line capacitance the more charges will flow closer to the surface forming the capacitor.
So for a coaxial cable with AC the energy in the shielded conductor flows closer to the outside surface and for the shield  it flows more on the surface facing the shielded conductor.
In the case of Derek's experiment during the transient energy that is delivered by moving electrons travels in conductor but a bit more electrons are on the side facing the other conductor. But that transient is just a fraction of a second and after that the energy will flow uniformly inside the conductor.
It is fairly easy to test by measuring where energy loss in the form of heat is and for DC you will see that the conductor heats uniformly on the entire conductor cross section.

[electrodacus]

How does sunlight get to the earth? Do you see wires connected between the sun and the earth?

Sun provides energy to earth through photons with most of the energy delivered in infrared but also what we call visible light and a bit of UV
With the photoelectric effect so photons will transfer their energy to electrons.

[electrodacus]

Does electricity flow in air or wires?

The correct answer is BOTH..

In the video a transient energy lights the bulb quickly because of fields.  But the wires take over, otherwise there could be no light output from a DC source.

It seems this whole confusion is cause by the attempt to make it one or the other.

Electric flow is due to electron flow and that happens in wire both for DC and AC/transient.
Unless you have electrons flying through the air from one conductor to another electrical energy will not travel through air.
And yes there are case like in that electrostatic generator video I posted but there there are very short distances in air and thousand of volts so that electrons are physically traveling through air delivering energy but that is not the case in Derek's experiment with 20V and 1m between conductors.

Derek's claim written in the thumbnail of his first video was "energy doesn't flow through wires" one of the most absurd claim I ever heard showing that he has no understanding of what energy means.

[PlainName]

you will see that the conductor heats uniformly on the entire conductor cross section

Easy for you to say. How about you demonstrate that?

[electrodacus]

you will see that the conductor heats uniformly on the entire conductor cross section

Easy for you to say. How about you demonstrate that?

People tested that well before I was born it just seems that internet instead of being this great learning tool it becomes a space for misinformation.
What about you just measure the electrical resistance of a copper pipe with thin walls and the electrical resistance of a copper bar with same diameter then let me know if there is a difference.
If there is a difference in resistance that means electrons from your multimeter traveled through the middle of the copper bar not just close to the surface.
You will see that resistance will be proportional with the copper section area so electron wave will travel uniformly through the material.

[TimFox]

Hontas Farmer is back still saying the Derek is both right and wrong acording to QFT/QED

QED (as all other QFTs) is a perturbation theory that extends Classical Electrodynamics to a quantum scale. QED is by no means a more fundamental theory than Classical Electrodynamics, and as being the extension, QED cannot contradict Classical Electrodynamics at macroscopic level. https://arxiv.org/pdf/1201.5536.pdf

Because QED is the perturbation theory, its approximate mathematical framework quickly falls apart when trying to describe classical systems (systems with billions of photons, electrons), as discussed in this paper: http://old.cft.edu.pl/~birula/publ/ClassLimit.pdf

In other words, QED has it own domain, and Classical Electrodynamics has its own domain. These domains do not overlap. Within their respective domains each theory has been validated experimentally to a very high degree.

In other words, to describe energy transfer in macroscopic systems proposed in Veritasium experiments, the only scientific tool Physics has is Classical Electrodynamics, and it is accurate at given scales.

It is sometimes interesting to compare two historical processes: 
[1]  After Constantine adopted Christianity for the Roman Empire, he wanted it codified and there were a long series of Councils, including Nicaea and Chalcedon, to render the new religion in axiomatic form.
[2]  Many centuries later, when the new quantum theories arose, there was a time between the wars when leading scientists, including Bohr, Einstein, Schrödinger, Heisenberg and others, debated theory and experiment to found what became known as Quantum Mechanics.  One guiding concept was the "Correspondence Principle" that related quantum results at microscopic scale to classical results at macroscopic scale, initially disregarding special relativity.  That "principle" is now less firm than before (depending on the physical situation under discussion), but a good example of a (non-handwaving) quantitative expression of this relationship is the Ehrenfest Theorem (published in 1927).
Those conversant in mathematics can find a description thereof in the Wikipedia article:  https://en.wikipedia.org/wiki/Ehrenfest_theorem

[vad]

Energy flows inside the wire both for AC and DC

Not necessarily. Take a superconductive wire at DC Inside the superconductor, electric field is zero everywhere (electric field potential is the same at any point inside the superconductor).

In other words: E = 0 inside such wire.

Electromagnetic energy flow is described by Poynting vector:

S = E x H = 0 (if E is zero vector, then its cross product is also zero vector no matter H field strength).

So no, at DC electromagnetic energy does not flow inside a superconductive wire.

If you replace superconductor with a wire that has resistance, then there will be an electric field inside the wire along its axis (equal to wire’s voltage drop divided by the length of the wire).

There is also a magnetic filed inside the wire when it conducts DC current. It can be quantified by Maxwell’s 4th equation. Such magnetic field circulates around wire’s axis. It’s strength is zero at the axis, and increases to a maximum value at wire surface.

Therefore EM energy flow inside such wire will be non zero. However the direction of the flow inside the wire will be strictly perpendicular to the wire  (remember direction of E, and the fact that cross product of two vectors is perpendicular to the vectors being multiplied). The total flow at surface (surface integral S over surface of the wire) is equal to Joule heating of the wire.

Remaining EM energy flows outside the wire. Using Poynting vector formula and some math, it can be shown that the energy flown outside the wire + Joule heating is all the energy that flows out of battery. From conservation of energy principal, we can declare that there no other EM energy flows.

[electrodacus]

Energy flows inside the wire both for AC and DC

Not necessarily. Take a superconductive wire at DC Inside the superconductor, electric field is zero everywhere (electric field potential is the same at any point inside the superconductor).

In other words: E = 0 inside such wire.

Electromagnetic energy flow is described by Poynting vector:

S = E x H = 0 (if E is zero vector, then its cross product is also zero vector no matter H field strength).

So no, at DC electromagnetic energy does not flow inside a superconductive wire.

If you replace superconductor with a wire that has resistance, then there will be an electric field inside the wire along its axis (equal to wire’s voltage drop divided by the length of the wire).

There is also a magnetic filed inside the wire when it conducts DC current. It can be quantified by Maxwell’s 4th equation. Such magnetic field circulates around wire’s axis. It’s strength is zero at the axis, and increases to a maximum value at wire surface.

Therefore EM energy flow inside such wire will be non zero. However the direction of the flow inside the wire will be strictly perpendicular to the wire  (remember direction of E, and the fact that cross product of two vectors is perpendicular to the vectors being multiplied). The total flow at surface (surface integral S over surface of the wire) is equal to Joule heating of the wire.

Remaining EM energy flows outside the wire. Using Poynting vector formula and some math, it can be shown that the energy flown outside the wire + Joule heating is all the energy that flows out of battery. From conservation of energy principal, we can declare that there no other EM energy flows.

Wire is used as a medium to transport energy. If wire has resistance then part of the energy will be wasted in the wire so less of the energy will be available to your load. A wire with no resistance to electrical flow like a superconductor means that no energy is lost while traveling through the wire.

That energy that is delivered before electron wave had the time to travel the length of the wire is due capacitance between wires and the lamp just happened in that particular example to be in series with that cable capacitance so current charging that capacitor made by wires will also pass through lamp/resistor.

The transmission line model provides exact predictions of what happens in a real transmission line and the phenomena associated with that.

[TimFox]

Of course, in vacuum, electron beams flow quite nicely.
In air, they flow less nicely in the form of arcs, sparks, and lightning.