Veritasium "How Electricity Actually Works"

[electrodacus]

Woah! No-one's talking resistance here (except you, as a diversion). You said "you will see that the conductor heats uniformly on the entire conductor cross section" - that is heat, thermal. I am wondering just how you can measure the internal temperature of a conductor, and you Internet isn't any help there.

So, just how do you see that? If you make a hole and place a probe you're affecting the conductor integrity, and even with a thermal imager you're only going to see the outside.

Or was this just another 'fact' or 'law' you made up on the spot?

I guess you will need to learn about another type of energy storage and that will be thermal storage.
If the electrons travel closer to the outside surface of the wire like in AC then resistive losses will show that so there will be no need to even measure the temperature.
In DC current flow the wire inductance is not relevant as magnetic field after it was created will remain constant thus no charging and discharging.

Just look at the case where I had the switch on for just 30ns vs when switch stayed ON and see the difference in energy transmission losses. All data is there for you to compare.

[vad]

So you understand that energy transfer is done by the wave of electrons.  How many electrons flow from the wire/copper pipe in Derek's experiment ?
Should be very substantial and directional if you want to account for the energy transferred in the first 65ns. What about the rest ?

No. The energy is transferred from EM field to electrons.

[vad]

I hope nobody argues here that oscillating EM field does carry energy. Examples are gamma rays, X-rays, UV light, visible light, microwave radiation, radio waves from terahertz to sub-hertz bands all transfer energy. Why is it so hard to realize that a constant EM field also carries energy?

[electrodacus]

No. The energy is transferred from EM field to electrons.

Can you be more specific ?
Before the switch placed next to battery is closed there is no magnetic field just electric field that is limited to battery and will not extend out plus it is a constant not a variable field.
The switch is a small capacitor so there is also a constant electric field between the contacts of the switch. So how come you need to close the switch to transfer energy if you already have an electric field that you say can transfer energy.
When you start moving the switch contacts you are changing the capacity of the switch so you now have redistribution of charges that results in variation in electric field (not the other way around).
Say you just moved the switch contacts but you did not closed them then depending on the direction you moved them (away from each other or closer to each other) you will have a current flowing in or out of the battery and out or in of the capacitor/switch (redistributing charges).
This charge redistribution will be completed only after the time needed for the electron wave created to travel the entire loop of wire plus the time for the wave interactions to settle down and so some time after you moved the switch a small current (the one needed to redistribute charge) will flow through the lamp.
So during this charge redistribution some of the energy was lost in the wire and the lamp/resistor.

Is there something that you do not agree with?
If there is something you disagree with please provide details explanations and the equations to back up what you are saying.
You all seems to make ambiguous statements without providing any proof.

[electrodacus]

I hope nobody argues here that oscillating EM field does carry energy. Examples are gamma rays, X-rays, UV light, visible light, microwave radiation, radio waves from terahertz to sub-hertz bands all transfer energy. Why is it so hard to realize that a constant EM field also carries energy?

Magnets have a constant magnetic field so do they transfer any energy if sitting next to a copper wire ?

[vad]

I hope nobody argues here that oscillating EM field does carry energy. Examples are gamma rays, X-rays, UV light, visible light, microwave radiation, radio waves from terahertz to sub-hertz bands all transfer energy. Why is it so hard to realize that a constant EM field also carries energy?

Magnets have a constant magnetic field so do they transfer any energy if sitting next to a copper wire ?

You need both electric and magnetic field: S = E x H

S is energy flow in any given point. Energy flow outside a region of space is a surface integral of S over surface of the region. I’m just writing this to forestall desire to add constant E field to your example (e.g. fix the magnet between electrodes of charged capacitor). Surface integral of S would be zero over any arbitrary surface. There would be no energy transfer.

[T3sl4co1l]

First show your solution for a circuit which extract 1% of the energy travelling in the vacuum in the diagram.

Create vacuum in the box and heat the outer wire (cathode) high enough so sufficient number of electrons will flow towards the inner wire (anode) to tap the 1% of energy.

They call this a diode vacuum tube, don’t they?

Now is your turn.

Careful: an unevenly heated box exhibits free electron drift.  A tube diode is a heat engine, albeit a very terrible one.



Consider this SPICE model fitted to 1/2 6AL5: it has a negative voltage in it, corresponding to the tail of the thermal energy curve.  This tail is exponential, interestingly enough (or, not at all), hence the ideal diode, and the nonlinear dependent source expresses the Child-Langmuir law at higher currents (evidently the cylindrical geometry gives an exponent somewhat lower than 3/2 (inverted as it's solving for voltage, hence 0.775).

So, for a 6AL5 that spends about a watt of heater power, you can put its two diodes in parallel, and get a whopping couple of microwatts out.

Whereas in an evenly heated box, the space charge will have some drift velocity, much as the electrons in the bulk conductor; it will be hard to extract any meaningful power from it though, as the maximum difference in energy is merely the difference in voltage, of course.

Tim

[vad]

Can you be more specific ?

Sure. Charged particle (an electron) gets accelerated in electric field.

[EEVblog]

You have a wrong understanding of what energy is and how it is transferred from source(battery) to load (lamp/resistor).

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.

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   
 

[SiliconWizard]

The truth is out there.

[electrodacus]

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   

This is not a political or philosophical discussion (or at least it should not be as it is not for me).
As you showed in your own video the transmission line model where you use finite RLC elements works perfect in predicting what you see in real tests.
Claim Derek made is that energy transfer is done outside the wire. Then the most pertinent question is why you even need the wires? They are quite expensive so it will be great if you could transfer electrical energy efficiency without needing them.
Also how come that from experimental result and transmission line calculations you get the same thing and that is energy output from the source equals energy delivered to lamp/load plus the losses in wires.  If wires were not delivering the energy then why will all the losses (except some ultra small leakage) are found as heat in the wires. The lamp or resistor is also a wire with higher resistance.
I'm willing to admit that I'm wrong if a pertinent alternative explanation is available with the correct math to back that up.
The simulation I have done in LTspice perfectly matches the experimental result Derek got in his last video and there you can look at all aspects of the model to see where energy is at any point in time.
To have electrical power (energy is the integral of that over time) you need both a voltage potential and a current flow. Unless voltage is so high that current flows through air the current will follow the path of least resistance and that is the wire.
Derek's only so called evidence is that he sees some energy used by the lamp way before the electron wave had time to travel through wire and that is very simply explained by the two capacitors formed by the transmission line on each side of the lamp and showed to be the case form the spice simulation of a transmission line.
That current is needed to charge the capacitors that are just an energy storage device and current cannot flow through them (ignoring again ultra small leakage) but flows in or out of them.
So everything will reduce to the question of current flows through capacitors or in/out of capacitors.
Charging a capacitor requires adding electrons on one side while removing the same amount from the other side. And the electric field that the extra electron produces to push an electron out of the other side will be there only after you have that electron imbalance. Is not the electric field that magically appears between the plates of a capacitors (they are an electric shield) but the field is the result of electron imbalance.   

[IanB]

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   

It seems that Mr Poynting got around a bit. I am familiar with the name from my field, chemical engineering:

https://en.wikipedia.org/wiki/Poynting_effect

(Nothing whatsoever to do with electricity.)

But it seems this is the same John Henry Poynting who is associated with the Poynting vector:

https://en.wikipedia.org/wiki/Poynting_vector

In the old days, it appears people were much more able to study everything:

https://en.wikipedia.org/wiki/John_Henry_Poynting

[electrodacus]

It seems that Mr Poynting got around a bit. I am familiar with the name from my field, chemical engineering:

https://en.wikipedia.org/wiki/Poynting_effect

(Nothing whatsoever to do with electricity.)

But it seems this is the same John Henry Poynting who is associated with the Poynting vector:

https://en.wikipedia.org/wiki/Poynting_vector

In the old days, it appears people were much more able to study everything:

https://en.wikipedia.org/wiki/John_Henry_Poynting

That guy was dead by the time people found out what atoms are made out of. I sure not heard about him at university (Electrical engineering in some east european country).

[TimFox]

Yeah, the guys who figured out how atoms are constructed are now dead, too.
Funny how real progress in science often builds on previous results.

[IanB]

This is not a political or philosophical discussion (or at least it should not be as it is not for me).

It seems to be 100% a philosophical discussion for you. You seem to be arguing about nothing.

As you showed in your own video the transmission line model where you use finite RLC elements works perfect in predicting what you see in real tests.

So that's good right? What is there to argue about?

Claim Derek made is that energy transfer is done outside the wire.

The claim Derek made is that enough power would arrive to light a lamp after a certain amount of time. The experiment showed this to be true. The calculations gave the same answer.

Then the most pertinent question is why you even need the wires? They are quite expensive so it will be great if you could transfer electrical energy efficiency without needing them.

Because the wires are part of the experiment. Derek did not suggest the wires are not needed. Quite the contrary, in fact. So why would you suggest the wires are not needed? Nobody even hinted at such a thing.

Also how come that from experimental result and transmission line calculations you get the same thing and that is energy output from the source equals energy delivered to lamp/load plus the losses in wires.

Because this is how things are supposed to work? Why is it strange to you that the calculations and experiment give the same result?

At this point, it is really not clear what you disagree with.

[bsfeechannel]

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   

The Poynting guys are away having a party while the wirists are here licking their own wounds.

[electrodacus]

At this point, it is really not clear what you disagree with.

I disagree with the main statement Derek made (it is in the video thumbnail) and that is "energy doesn't flow in wires"
There is absolutely no evidence for that.  If you think you know what that evidence is then let me know.

[hamster_nz]

At this point, it is really not clear what you disagree with.

I disagree with the main statement Derek made (it is in the video thumbnail) and that is "energy doesn't flow in wires"
There is absolutely no evidence for that.  If you think you know what that evidence is then let me know.

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.

[electrodacus]

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.

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.

[bsfeechannel]

I must have missed it. Please explain what experiment was done,

Very funny. The only thing I did in this thread was to indicate all the experimental data that support the energy flowing in space.

what was predicted by the S=JV folks, and what was found. (And why Poynting-Heaviside-etc. do not talk about it.)

What they accomplished no one knows. What they didn't, we know. They didn't manage to come up with an alternative that doesn't break causality, locality, gauge invariance or a combination of these.

That's why, despite objections regarding its counterintuitive nature, Poynting is the most probable explanation for the flow of energy.

I guess you're correct, something true is now in the bin for millions of people. How remarkable.

Truth? Science is about knowledge. If you are the truth bearer, you're not doing science.

I also wonder how exactly all physicists proposing alternatives to the Poynting theorem never saw Derek's antennae coming in the whole 20th century. They must feel very silly now (no).

They didn't. But their peers did and criticized their proposals. That's why Poynting still stands.

[hamster_nz]

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.

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.

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]

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.

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]

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.

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]

You have a wrong understanding of what energy is and how it is transferred from source(battery) to load (lamp/resistor).

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.

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   

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]

Why will I be bothered by that ?

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.