"Veritasium" (YT) - "The Big Misconception About Electricity" ?

[hamster_nz]

There's nothing more absurd than looking at physics equations and say "how?", it's not a religion, it's an axiom.

Forget the equations. What I'm talking about is how exactly an electron exerts force on the others 1 m away. Does it have a barge pole to poke their fellow subatomic particles at a distance?

Ignoring magnetism, in classical theory charges respond to the local gradient of the electric field. And the value (and therefore the gradient) of the electric field is influenced by the locations of the charges.

Much like the same way apples fall to the earth due to gravity, and the locations of mass define the gravitational field. There is no string pulling the apple down. It just does what comes naturally.

[Naej]

There's nothing more absurd than looking at physics equations and say "how?", it's not a religion, it's an axiom.

Forget the equations. What I'm talking about is how exactly an electron exerts force on the others 1 m away. Does it have a barge pole to poke their fellow subatomic particles at a distance?

It changes the potential, and electrons are sensitive to potential, and in particular its gradient.
How does an electron grow an electric field by the way? It waters it, until a proton comes near it and reaps most of what was sown?

But since you are obsessed with antennas, when exactly a piece of conductor decides it is not a wire anymore and becomes an antenna?

They always are. Often they are poor antennae at most frequencies, which limits interference.
How do you decide when exactly a wire becomes a coil? A capacitor?

[ejeffrey]

A quantitative discussion of the effect of normal insulation layers on velocity factor in antenna construction:
https://lowpowerlab.com/guide/rf-best-practices/velocity-factor/
Summary:
0.95 for bare copper wires
additional factor of 0.95 to 0.98 when adding normal insulating materials (PVC, polyethylene, PTFE)
These factors are important when calculating antenna length.

To get down to 0.66, you need a coaxial construction such as RG-58/U with solid polyethylene dielectric
With RG-62A/U, which has an internal construction which is roughly half air and half polyethylene (annular geometry), the characteristic impedance rises to 93 ohms, and the velocity factor is 0.83.
Foamy dielectrics have similar velocity factors.

Yep this is more what i would expect, in the order of single digit percent difference from adding insulation.

For the kind of precision Veritasiums experiment is working with this certainly would not make much of a difference. The experiment works fine and shows expected results. It just doesn't clearly show the 1m/c delay claimed in the original video.

It doesn't show the exact number it particularly clearly but it does show it.  The yellow trace *starts* rising close enough to 3 ns after the green trace turns on.  It does takes about 15-20 ns to reach the ~5V plateau.  This is to be expected, and should show up in the HFSS models, but doesn't really detract qualitatively from the point: "the load begins to turn on significantly in a time approximately light crossing the gap".  Yes, at exactly 3 ns the current is still quite small but it it rises rapidly to a significant voltage.  Arguing about the precise dynamics is basically already conceding the point of the whole thought experiment.

Given the nice setup with rigid metal pipe on supports I would have wanted to slide the rods closer together, say 0.5 m and see how that moved the trace.  But I don't know that that would have actually been helpful for the target audience.

[aetherist]

Some comments found on Veritasium's youtube.
electroBoom        5 days ago (edited)
This was a greatly detailed video and I think we are pretty much on the same page! Thanks for the shoutout and going through the trouble of clarification.
P.S. by the way, the resistor in your experiment didn't quite match the lien impedance, other you would get half your supply voltage right away. But I mean with such small capacitance and inductances, the probing itself could have added some parasitic components to the lines.
PPS: Like I said above "pretty much on the same page"! It is a complex subject, and I think some nuances could have been addressed better. Maybe Derek and I could sit together and react to nuances to clarify things!
Veritasium             5 days ago
We were all initially expecting half the applied voltage. BUT we modelled the circuit including coupling the wires on the left side of the resistor to the wires on the right side. In that case you get less than half and then the overshoot.

Alex       10 hours ago
just admit you were wrong
electroBoom         5 hours ago
 @Alex  ?! Why? I wasn't, and Derek doesn't say I was wrong
Alex           3 hours ago
 @ElectroBOOM  well from what I rembered from your video you said Derek was wrong and he explained why he wasn't
So that means you were wrong when you claimed he was wrong.  And I know there is room for interpretation in both of your vid.

[aetherist]

Some comments found on Veritasium's youtube.
EEVblog   4 days ago (edited)
Happy that you finally did the follow-up video. It's excellent and well thought out and adds some excellent new detail. It won't stop the nerds arguing though, the EEVblog forum thread on the video is up to 75 PAGES of debate, LOL. The argument comes down to the fact that most practical engineers do not need to think in these terms, especially at DC. But I think you can sleep well at night after this one.
The only thing I didn't see mentioned was the Quantum Electrodynamics (QED) hypothesis that might ultimately trump Poynting and Maxwell when it comes to energy flow inside vs outside the wire. But I can understand how that might side track this video completely.
I know the Poynting/Maxwell math still works out for DC, but it's just The Vibe. So it's inside the wire at DC for this crusty electronics engineer :-P
Well done.
Comment on EEVblog by mad aetherist    1 second ago
 @EEVblog  I dont think that QED calcs could give numbers for delays (& voltages) that accord with what was found for the induced trace for the bulb/resistor in any such experiment (eg Veritasium's)(eg AlphaPhoeinix's etc). Or even close.
And, if the numbers do accord, what does it prove or confirm or support, almost nothing. Praps it would support that there is an aether.


EEVblog      4 days ago (edited)
 @tpog I was thinking of finding the world expert on QED and having a chat, anyone know who that is? I think that if you can do a physical experiment to prove QED and energy flow inside a wire, you'd win a Nobel prize. and change physics forever. And that's the problem with discussing it, AFAIK there is no practical experiment confirming it. I tried to read some researc papers on it, but my head exploded.


EEVblog    4 days ago (edited)
 @EpicBunty  Do we know everything? - Probably not. QED sound promising, and if true it likely trumps Maxwell/Poynting theory. In the same way that Einsteins general theory of relatively up-ended Newtons.
What we already know - Maxwell/Poynting is correct, because it provides a method to explain things that verifies with actual measurements. But we also still use Newtons laws to do lots of practical stuff, there is just a higher level theory available. We can't be 100% sure that a higher level theory above Maxwell/Poynting does not exist. And even if there is, for almost everything we'd still use Maxwell/Poynting anyway. And as Derek explained, we still use Ohms law and lumped transmission line theory, and transformer theory, and antenna theory to do practical stuff, because we don't need to fuss over the details or exactly how the energy flows.
Dragrath1      4 days ago      @EEVblog  Yeah the problem with trying to do a practical modelling of this is that  the Feynman path integrals for it mean that there are actually infinite integrals which have to be computed covering every single possible quantum interaction. These terms rapidly decay way to have negligible effects on the final calculation the larger their action is but as you start scaling the system to macroscopic sizes of a circuit even the number of relevant calculations you would need to produce a result using QED blows up towards infinity as the number of possible interactions increases.  With a powerful quantum computer it actually probably wouldn't be that hard to do as it could compute every path simultaneously but in the absence of that computational irreducibility rears its ugly head and the measurement precision limits you ability to robustly test the results.

the Feynman path integral is from a theoretical perspective beautiful and elegant but from a practical prospective it is so exceptionally unwieldly that you will never quite get the result you want within finite time.

EEVblog           4 days ago
 @Dragrath1 Yeah, I would not bet on being able to come up with practical measurement that can prove QED, but I would not rule it out either. Nobel prize on offer for the one that does though.

[aetherist]

Some comments found on Veritasium's youtube.
The Science Asylum   4 hours ago
11:08 "And at that instant, the electric field inside the conductor is no longer zero..." Thank you! I felt like I was only person saying this out loud.

[aetherist]

Some comments found on Veritasium's youtube.
AlphaPhoenix 5 days ago.
Fantastic revisit! The animations and the simulations were spot-on, and great at showing the difference between the transient “first-second” effect, and the steady-state “rest of time” behavior. The whole “expanding loop of current” thing is a great way to phrase it, because after that poynting loop expands to match the actual physical loop of wire, then stuff starts to behave normally and all of the power is transmitted around the loop very close to the wire. I still hold that for this simple circuit, turning on a lightbulb with wires much smaller around than they are long, the effect of surface charge vs internal charge is negligible, so you can ignore any skin-effect stuff and say that “mobile” electrons are indeed pushing on other “mobile” electrons using their fields, but I totally agree that that’s a simplification, just a simplification that makes the intuition a lot easier. I also need to do some math about how far the average “electron” is displaced in order to build the initial charge distribution around some typical circuit elements - axial flow is the only way I understand those charge distributions getting built, and this whole endeavor has made me think hard about what that means. Someday when I think I understand it better I’ll edit up my pt.2 response video - thanks for the shoutout! I’ve got a great experiment in the works to show the “expanding poynting loop”

[adx]

I rewatched Derek's video after a week of sort of thinking about it (been busy).

I thought it was good - the aesthetics, and mash up of what's been going on in video land since the first one. The higher 'res' HFSS simulation was really spectacular and does help clarify details. A much better, cleaner, denser, correcter explanation and obviously very carefully chosen wording which clarified some things even after 'all this time'. The simplifications (like Drude model conduction) I think are ok for the general audience this is aimed at, and conceptually "not wrong".

But one part that did increasingly 'grate' (or nicer word for that) is where it said the marbles going through pipe model was a misconception (and some of the things about energy not flowing in the wires) - IMHO that's towing the line of physics convention, which may be well justified academically, but wrong to say something is a "misconception" if it is what is really happening:

I can't remember everything that was discussed in this thread without looking, but as far as I got, it was that the fluid in a pipe model is correct - pressure of electron fluid, constrained by a pipe (in this case solid metal). The pipe expands under pressure, a mechanical pressure. The forces are the same thing - mobile, fluid. They all push on each other in the fluid similar to a normal fluid (barely compressible, electrically neutral, mobile). (The difference about the pipe is in the constraint - pipe wall, surface charge between empty space and neutral fluid.) So they do very much push each other down the wire, and it is how energy is transmitted.

But it isn't necessarily where the energy travels - I'll choose to steer away from the "path of energy" argument (like Sredni's question) after coming up partly blank a coupe of months ago. No one knows where (or even if). Thinking about the fluid 'analogy' of a hydraulic system in a digger (again) - how can the energy travel in the pipes, if it is the pressure difference between them that does the work? If it is in the space between the fluids (and definitely not in the fluid), where does the energy travel? (Rhetorical - I chose to steer away. Also combining quantum surface effects with speed-of-light energy transfer, things start sounding awfully like Aetherist's electons.)

So the marbles model is at worst "misleading".

Anyway, I like to draw over scope screenshots too, below is my first hack at working out a 1m transit time (without checking, admittedly if it had come up with something like 5ns then I might not have posted the PNG):

[aetherist]

............But it isn't necessarily where the energy travels - I'll choose to steer away from the "path of energy" argument (like Sredni's question) after coming up partly blank a coupe of months ago. No one knows where (or even if). Thinking about the fluid 'analogy' of a hydraulic system in a digger (again) - how can the energy travel in the pipes, if it is the pressure difference between them that does the work? If it is in the space between the fluids (and definitely not in the fluid), where does the energy travel? (Rhetorical - I chose to steer away. Also combining quantum surface effects with speed-of-light energy transfer, things start sounding awfully like Aetherist's electons.)

So the marbles model is at worst "misleading".

Anyway, I like to draw over scope screenshots too, below is my first hack at working out a 1m transit time (without checking, admittedly if it had come up with something like 5ns then I might not have posted the PNG):

On my copy i wrote a delay of  4.1 ns. But this was not an accurate estimate, your  3.0 ns is probly more accurate.
Actually i had another go at it myself & it came to 2.2 ns.
Veritasium intentionally avoided using a 50 ps/div scale, he went for a  50 ns/div scale, koz he didn’t have any answers for the initial rise & the initial plateau.
What is your own explanation for the rise & plateau?

[aetherist]

A quantitative discussion of the effect of normal insulation layers on velocity factor in antenna construction:
https://lowpowerlab.com/guide/rf-best-practices/velocity-factor/
Summary:
0.95 for bare copper wires
additional factor of 0.95 to 0.98 when adding normal insulating materials (PVC, polyethylene, PTFE)
These factors are important when calculating antenna length.

To get down to 0.66, you need a coaxial construction such as RG-58/U with solid polyethylene dielectric
With RG-62A/U, which has an internal construction which is roughly half air and half polyethylene (annular geometry), the characteristic impedance rises to 93 ohms, and the velocity factor is 0.83.
Foamy dielectrics have similar velocity factors.

Yep this is more what i would expect, in the order of single digit percent difference from adding insulation.

For the kind of precision Veritasiums experiment is working with this certainly would not make much of a difference. The experiment works fine and shows expected results. It just doesn't clearly show the 1m/c delay claimed in the original video.

It doesn't show the exact number it particularly clearly but it does show it.  The yellow trace *starts* rising close enough to 3 ns after the green trace turns on.  It does takes about 15-20 ns to reach the ~5V plateau.  This is to be expected, and should show up in the HFSS models, but doesn't really detract qualitatively from the point: "the load begins to turn on significantly in a time approximately light crossing the gap".  Yes, at exactly 3 ns the current is still quite small but it it rises rapidly to a significant voltage.  Arguing about the precise dynamics is basically already conceding the point of the whole thought experiment.

Given the nice setup with rigid metal pipe on supports I would have wanted to slide the rods closer together, say 0.5 m and see how that moved the trace.  But I don't know that that would have actually been helpful for the target audience.

Berni & TimFox know that Velocity Factor duz not tell us the speed of elekticity. Velocity Factor is simply a radio ham fudge factor that gives good numbers for antennas.
Berni & TimFox know that Velocity Factor changes with GHz. Hence it has little to do with the pure speed of elekticity.
Berni & TimFox know that there is no experiment or test that has ever been carried out that links Velocity Factor to the speed of elekticity. Not for bare wire, not for insulated wire.
Any/every  proper test will show that insulated wire has a speed of elekticity of  2c/3.

Berni & TimFox don’t know that it is not simply  what is inside a coax that determines the speed of elekticity.
The speed of elekticity along a coax is the sum of the speed of elekticity on the Cu wire, & the speed of elekticity on the outside of the sheath (which is usually fully insulated).
Seeesh, i am getting tired of casting pearls.

[TimFox]

I know that the speed of a signal down a transmission line is the usual function of the inductance and capacitance per unit length.
In my career, I have measured transmission lines to verify this.
I have built resonant circuits using coax lines.
I have built delay lines from discrete inductors and capacitors.
I have used coax cables with and without the PVC outer insulation.
I have never seen the mythical behavior you wave your hands about.
I am getting tired of stepping through your “pearls”.

[Berni]

Berni & TimFox know that Velocity Factor duz not tell us the speed of electricity. Velocity Factor is simply a radio ham fudge factor that gives good numbers for antennas.
Berni & TimFox know that Velocity Factor changes with GHz. Hence it has little to do with the pure speed of electricity.
Berni & TimFox know that there is no experiment or test that has ever been carried out that links Velocity Factor to the speed of electricity. Not for bare wire, not for insulated wire.
Any/every  proper test will show that insulated wire has a speed of electricity of  2c/3.

Berni & TimFox don’t know that it is not simply  what is inside a coax that determines the speed of electricity.
The speed of electricity along a coax is the sum of the speed of electricity on the Cu wire, & the speed of electricity on the outside of the sheath (which is usually fully insulated).
Seeesh, i am getting tired of casting pearls.

Velocity factor is not just a term that only works in RF. it is just a more convenient way of saying the speed without having to write out the speed as a huge number.

If velocity factor was significantly different for various frequencies then you would get your signal distorted after going trough a long coax cable as parts of the signal would separate out in time. This would be particularly visible when sending a square wave trough it, instead what tend to happen is the square wave getting rounded off, this is because the higher frequencies tend to cause more loss in the dielectric. This is why coax for >10GHz is special and usually insanely expensive.

You can do the experiment yourself if you don't believe it. Take a few different kinds of line such as classic solid RG58, foam core RG6 or some 300Ohm ladderline. Feed a fast square wave pulse into one end (with proper matching for the line impedance) and measure the time delay with a scope. You will see that the RG58 is very close to the 2/3c yet the ladder line is more like 9/10c while the foam RG6 is somewhere in between. As long as you have 10s of meters of cable you don't even need a particularly fast scope to measure it. You can also use a LCR meter to verify the equation that velocity factor is determined by the inductance and capacitance. In particular the capacitance part is what changes when you introduce a plastic dielectric.

[aetherist]

Berni & TimFox know that Velocity Factor duz not tell us the speed of electricity. Velocity Factor is simply a radio ham fudge factor that gives good numbers for antennas.
Berni & TimFox know that Velocity Factor changes with GHz. Hence it has little to do with the pure speed of elekticity.
Berni & TimFox know that there is no experiment or test that has ever been carried out that links Velocity Factor to the speed of elekticity. Not for bare wire, not for insulated wire.
Any/every  proper test will show that insulated wire has a speed of elekticity of  2c/3.

Berni & TimFox don’t know that it is not simply  what is inside a coax that determines the speed of elekticity.
The speed of elekticity along a coax is the sum of the speed of elekticity on the Cu wire, & the speed of elekticity on the outside of the sheath (which is usually fully insulated).
Seeesh, i am getting tired of casting pearls.

Velocity factor is not just a term that only works in RF. it is just a more convenient way of saying the speed without having to write out the speed as a huge number.

If velocity factor was significantly different for various frequencies then you would get your signal distorted after going trough a long coax cable as parts of the signal would separate out in time. This would be particularly visible when sending a square wave trough it, instead what tend to happen is the square wave getting rounded off, this is because the higher frequencies tend to cause more loss in the dielectric. This is why coax for >10GHz is special and usually insanely expensive.

You can do the experiment yourself if you don't believe it. Take a few different kinds of line such as classic solid RG58, foam core RG6 or some 300Ohm ladderline. Feed a fast square wave pulse into one end (with proper matching for the line impedance) and measure the time delay with a scope. You will see that the RG58 is very close to the 2/3c yet the ladder line is more like 9/10c while the foam RG6 is somewhere in between. As long as you have 10s of meters of cable you don't even need a particularly fast scope to measure it. You can also use a LCR meter to verify the equation that velocity factor is determined by the inductance and capacitance. In particular the capacitance part is what changes when you introduce a plastic dielectric.

A measure of the delay for the reflexion of a signal or pulse or something for a straight (single) bit of insulated Cu would do the job (say 10 m long if a good scope).
Not coax. Not twin. Not ladderline.
I say the speed of elekticity will be  5.0 ns/m, which is 2c/3.
A bare wire would be  3.4 ns/m, which is  c/1.
This is the speed of the fastest signal (which will probly be very strong with a steep rise, if the scope is a good scope).
But i haven't got a scope.

[aetherist]

I know that the speed of a signal down a transmission line is the usual function of the inductance and capacitance per unit length.
In my career, I have measured transmission lines to verify this.
I have built resonant circuits using coax lines.
I have built delay lines from discrete inductors and capacitors.
I have used coax cables with and without the PVC outer insulation.
I have never seen the mythical behavior you wave your hands about.
I am getting tired of stepping through your “pearls”.

If the leading edge of a (DC) signal is slowed due to the presence of a parallel wire then that would be a big problem for my new elekton elekticity.

[adx]

On my copy i wrote a delay of  4.1 ns. But this was not an accurate estimate, your  3.0 ns is probly more accurate.
Actually i had another go at it myself & it came to 2.2 ns.

All reasonable. I think mine was just luck, but I have done this before and tend to know how to eyeball it to get it a bit tighter.
 

What is your own explanation for the rise & plateau?

Probing (is my guess).

Probes like that are not supposed to be used (for accuracy) at GHz - they might be set to x1 (if they do that at all) which adds significant capacititve loading (what we like* to call complex impedance). They can't accurately measure voltage without applying a low impedance at HF (whilch will slow the rise), and they can't be something like a 50 Ohm load if they are measuring a 560R resistor or whatever it is. Many pages back we went over ways to measure it into a 50R input of a very high speed scope for this test, and differentially (or isolated). I'm not surprised it wasn't done (except the differential with channel math) - showing probes hanging like this, after a scope is lugged to the top of a ladder, is much more accessible than some perplexing RF apparatus with baluns and calibration (VNA, IFFT). Even the screenshot is just from pressing the stop button on the live signal (you can see it in real time in the video - the FM radio stations get visually averaged or at least fuzzed out).

* except me a couple of pages back

I say this because the other tests and simulations, the direct signal was sharp, and 'long way round' (including reflections) had progressively slowed rise (someone said dispersion, also skin effect). In this one you can see it is about the same - limited by probing and maybe drive a little, but not the scope.

It's also driven single-ended (almost certainly from the way the coax is hooked up behind the probe clip), and that will introduce the funny ground effects that so perplexed AlphaPhoenix in the pre-math channels.

All the funny little ripples (not the FM radio regular + beating sinewaves, I mean the little peaks near the edges) I don't know, only way to know is to tinker with the setup and work it out. Bit risky up a ladder with $ $ $ $ $ scope. (Forum SW didn't like all those $es together)

[Berni]

A measure of the delay for the reflexion of a signal or pulse or something for a straight (single) bit of insulated Cu would do the job (say 10 m long if a good scope).
Not coax. Not twin. Not ladderline.
I say the speed of electricity will be  5.0 ns/m, which is 2c/3.
A bare wire would be  3.4 ns/m, which is  c/1.
This is the speed of the fastest signal (which will probly be very strong with a steep rise, if the scope is a good scope).
But i haven't got a scope.

If you have a straight conductor with nothing else around it you have created an antenna.

The speed in these is well known to be close to the speed of light since this is important in antenna design. They are designed according to the wavelength and as you see using insulated wire makes a difference of only a few %, certainly not 2/3c. And it makes sense sine most of the surrounding environment is air with a tiny bit of plastic in it.

There is also the problem with monopole antennas that you can't make a true monopole antenna. Current always flows in loops so driving this kind of antenna also pushes an identical reverse current into the ground. So whatever is connected to ground becomes 'the other piece of wire'. In real antennas this ground tends to be connected to a metal grounding rod right next to it to make the planet itself the other pole of the 'monopole'

So to actually do your experiment properly one would need to do it using a 10m metal rod flying in the air with the measurement setup stuck to one end of it. That way you would have nothing conductive anywhere near the antenna (inducing the ground) while the test electronics are powered by batteries. What you would get in that case is mostly the ground of your test equipment getting wiggled up and down at the square wave pulse rate. The metal case of the equipment acting mostly as the antenna while using the 10m pole as its earth.

[penfold]

What is your own explanation for the rise & plateau?

Probing (is my guess).

Yeah... this ain't exactly paradigm-shifting experimentation, with absolutely no discredit to Derek at all, the experiment is only really set up to answer the question "does energy arrive at the load before anything traveling at the speed of light could travel the distance of the wires?": whilst it'd be nice to see something that truly matched (simplified) theory and simulation... it'd take a substantial amount of effort to simulate all physical artifacts or eradicate anything not simulated. So, I don't blame him, but recirculating my original stance, it's quite improper to draw any other conclusion without further investigation from such an experiment.


Anyway, interesting point you (adx) made previously about the hydraulic analogy... I did wonder, much earlier on, whether Derek was simply setting us up for a video entitled "The big misconception about hydraulics". Extending the "rubber hoses in air" (the hoses being somewhat compliant and able to transmit a pressure wave), I wondered what would happen if the hydraulic circuit were constructed, rather than with tube in air, with cavities, channels, or tunnels within a soft and gelatinous medium (low-durometer silicone rubber perhaps). From the pressure of fluid within a cavity, the resulting dimensional change of that cavity could transmit a wave throughout the medium and affect the displacement of fluid elsewhere in the "circuit"... interestingly, because we have some control of the material properties, we can have a medium that only conveys the wave resulting from pressure and surely could only transmit power in a transient/continuously varying sense. We could at least hypothesize a fluid that is inelastic but moderately viscous (and immiscible with the hydraulic fluid) and can move slightly under the influence of friction with that moving fluid - where we could have a wave of movement. I've not really thought about it beyond that point, but it is easy to see where the aether concept arose.

[aetherist]

A measure of the delay for the reflexion of a signal or pulse or something for a straight (single) bit of insulated Cu would do the job (say 10 m long if a good scope).
Not coax. Not twin. Not ladderline.
I say the speed of electricity will be  5.0 ns/m, which is 2c/3.
A bare wire would be  3.4 ns/m, which is  c/1.
This is the speed of the fastest signal (which will probly be very strong with a steep rise, if the scope is a good scope).
But i haven't got a scope.

If you have a straight conductor with nothing else around it you have created an antenna.

The speed in these is well known to be close to the speed of light since this is important in antenna design. They are designed according to the wavelength and as you see using insulated wire makes a difference of only a few %, certainly not 2/3c. And it makes sense sine most of the surrounding environment is air with a tiny bit of plastic in it.

There is also the problem with monopole antennas that you can't make a true monopole antenna. Current always flows in loops so driving this kind of antenna also pushes an identical reverse current into the ground. So whatever is connected to ground becomes 'the other piece of wire'. In real antennas this ground tends to be connected to a metal grounding rod right next to it to make the planet itself the other pole of the 'monopole'

So to actually do your experiment properly one would need to do it using a 10m metal rod flying in the air with the measurement setup stuck to one end of it. That way you would have nothing conductive anywhere near the antenna (inducing the ground) while the test electronics are powered by batteries. What you would get in that case is mostly the ground of your test equipment getting wiggled up and down at the square wave pulse rate. The metal case of the equipment acting mostly as the antenna while using the 10m pole as its earth.

The say 10 m wire could be stretched high above the dirt, from the say 3rd floor of a building, using plastic rope going to the say adjacent building.
But i would not worry too much. Minor reflexions etc shouldn’t matter much, as long as there is a clear strong non-ambiguous signal.
I would connect the wire to the scope (ie to receive a pulse), & not worry about completing some kind of circuit (or about using ground)(but i scored i think 51/100 for Electricity-1).

I suppose that u would need the scope to measure voltage across a resistor stuck on the near end of the wire.

Rather than using a (simple) pulse, i would prefer to use a (complicated)  12 V lead acid battery. Feed the wire from the negative terminal. Don’t have any connection to the positive terminal. Possibly use a special switch.

No great need to looz sleep about all of the things needed to make the experiment perfect.
The Nobel Committee will have an easy job.

[Berni]

The say 10 m wire could be stretched high above the dirt, from the say 3rd floor of a building, using plastic rope going to the say adjacent building.
But i would not worry too much. Minor reflexions etc shouldn’t matter much, as long as there is a clear strong non-ambiguous signal.
I would connect the wire to the scope (ie to receive a pulse), & not worry about completing some kind of circuit (or about using ground)(but i scored i think 51/100 for Electricity-1).

I suppose that u would need the scope to measure voltage across a resistor stuck on the near end of the wire.

Rather than using a (simple) pulse, i would prefer to use a (complicated)  12 V lead acid battery. Feed the wire from the negative terminal. Don’t have any connection to the positive terminal. Possibly use a special switch.

No great need to looz sleep about all of the things needed to make the experiment perfect.
The Nobel Committee will have an easy job.

A scope measures all signals in reference to ground, so you have to connect ground somewhere.

The signal generator making the pulse (or a battery and switch) also has two terminals, so you need to connect the other end to something to see a signal at all. The source can only 'pump' electrons over. So if you want to push electrons into the 10m rod you have to pump them from somewhere.

[SandyCox]

The Nobel Committee will have an easy job.

For once I agree with you!

[TimFox]

I know that the speed of a signal down a transmission line is the usual function of the inductance and capacitance per unit length.
In my career, I have measured transmission lines to verify this.
I have built resonant circuits using coax lines.
I have built delay lines from discrete inductors and capacitors.
I have used coax cables with and without the PVC outer insulation.
I have never seen the mythical behavior you wave your hands about.
I am getting tired of stepping through your “pearls”.

If the leading edge of a (DC) signal is slowed due to the presence of a parallel wire then that would be a big problem for my new electon electricity.

"the leading edge of a (DC) signal" is nonsensical:  what you mean is the leading edge of a Heaviside step function, which is not DC.  Such step-function pulses or waveforms never exist without a source impedance from the generator.  The end of the transmission line where you connect the generator is a discontinuity, and may well have parallel capacitance.  What happens to a step function applied through a resistance to a capacitance in parallel with another impedance (the characteristic impedance of the transmision line)?  Spoiler:  you get an increased rise time.  Quantitative values depend on the actual parameters.

Anytime you have two wires, you have a transmission line.  Two wires lying on top of your bench makes a crappy transmission line, by which I mean that its parameters are not well-defined, nor are they constant down the length of the wire, as the would be in a well-made coaxial, twisted-pair, or twin-lead line.

[aetherist]

The say 10 m wire could be stretched high above the dirt, from the say 3rd floor of a building, using plastic rope going to the say adjacent building.
But i would not worry too much. Minor reflexions etc shouldn’t matter much, as long as there is a clear strong non-ambiguous signal.
I would connect the wire to the scope (ie to receive a pulse), & not worry about completing some kind of circuit (or about using ground)(but i scored i think 51/100 for Electricity-1).

I suppose that u would need the scope to measure voltage across a resistor stuck on the near end of the wire.

Rather than using a (simple) pulse, i would prefer to use a (complicated)  12 V lead acid battery. Feed the wire from the negative terminal. Don’t have any connection to the positive terminal. Possibly use a special switch.

No great need to looz sleep about all of the things needed to make the experiment perfect.
The Nobel Committee will have an easy job.

A scope measures all signals in reference to ground, so you have to connect ground somewhere.

The signal generator making the pulse (or a battery and switch) also has two terminals, so you need to connect the other end to something to see a signal at all. The source can only 'pump' electrons over. So if you want to push electrons into the 10m rod you have to pump them from somewhere.

I suspect that the scope is its own ground. In any case ground is only a worry if voltage is critical, which here it aint, what we need is good nanoseconds not good nanovolts.

Re seeing a signal at all, that is old (electron) electricity. My new (elekton) elekticity don’t need no circuit.
Hence the X will confirm my elektons whilst killing your electrons.
The elektons are continuously circulating on the negative terminal of the lead acid battery. Fed from the electrolyte in the cell. They do not need any pumping or pushing. They merely need a contact, & off they go, at the speed of light (albeit slowed by the drag of the Cu surface)(ie the drag of the drifting electrons in the Cu)(plus a little bit of drag due to having to plough through free surface electrons).
Sweden here i kum.

[TimFox]

"what we need is good nanoseconds not good nanovolts"

When dealing with young junior engineers doing digital hardware at work, I found that they had a similar cavalier attitude about the "nuisance" ground clip supplied with the oscilloscope probe, and generally lost it somewhere.
The "bouncy-bouncy" on their displayed waveforms was the result.
I responded by anathematizing "ground" as the "G word" that should not be used in polite company:  specific terms such as "circuit common", "ground plane", "protective earth", "coax shield", etc. were required.

There are well-defined methods, described in the oscilloscope literature, for obtaining high-fidelity displays of fast waveforms.  My personal favorite are the coaxial test points that can be soldered directly to the circuit board, and fit the barrel and point of standard oscilloscope probes.  Never, ever, depend on your scope dangling somewhere on the bench, possibly connected to a green wire, to be a good "ground" reference by itself.

[aetherist]

I know that the speed of a signal down a transmission line is the usual function of the inductance and capacitance per unit length.
In my career, I have measured transmission lines to verify this.
I have built resonant circuits using coax lines.
I have built delay lines from discrete inductors and capacitors.
I have used coax cables with and without the PVC outer insulation.
I have never seen the mythical behavior you wave your hands about.
I am getting tired of stepping through your “pearls”.

If the leading edge of a (DC) signal is slowed due to the presence of a parallel wire then that would be a big problem for my new electon electricity.

"the leading edge of a (DC) signal" is nonsensical:  what you mean is the leading edge of a Heaviside step function, which is not DC.  Such step-function pulses or waveforms never exist without a source impedance from the generator.  The end of the transmission line where you connect the generator is a discontinuity, and may well have parallel capacitance.  What happens to a step function applied through a resistance to a capacitance in parallel with another impedance (the characteristic impedance of the transmision line)?  Spoiler:  you get an increased rise time.  Quantitative values depend on the actual parameters.

Anytime you have two wires, you have a transmission line.  Two wires lying on top of your bench makes a crappy transmission line, by which I mean that its parameters are not well-defined, nor are they constant down the length of the wire, as the would be in a well-made coaxial, twisted-pair, or twin-lead line.

I appreciate your input as usual. However that is old electricity.
A single wire is a transmission line. All i need is the leading edge of a rise, ie of a step, the rise time itself is not critical.
I suppose that Heaviside didn’t ever consider a single wire to be a transmission line.
Whether the initial rise can be called DC is probly a side issue.

The source might be problematical. I like to invoke a lead acid battery, koz i know that elektons live (mostly) on the positive terminal.
I would be happy to try using a balloon that has been rubbed. Just touch the balloon on the Cu (ie on the transistor on the end of the Cu). But i am not sure whether my elektons live on balloons.
I would be wary about letting electrodacus touch the resistor with one of his capacitors. Capacitors have more elektons on one plate than the other.
And i am unsure about pulses provided by scopes.  Are there any elektons in that there pulse?  Dunno.

Howardlong had no trouble getting a good pulse along & around & back on his 4 ft of crappy transmission ladderline on his kitchen table using a 20 GHz scope.  And he got a delay of 79 ps which confirmed Veritasium. But, Howardlong didn’t show us the arrival of the main pulse, he only showed us the initial current due to inductance across the 25 mm from one Cu to the other Cu of his ladderline. Pity, it would have proven my elektons, alltho as i have said i would prefer tests on a single line (with reflexion) rather than using a circuit.

[TimFox]

With transmission lines, especially those of substantial length, the voltage and current are local, and don't include uncontrolled long wires outside the measurement.
Ideally, one defines a plane, perpendicular to the long direction of the coaxial cable (in this example) and the ideal voltage probe/oscilloscope measures the voltage from center to outer conductors in that plane, and the ideal current probe measures the current through the inner conductor passing through that plane.
Practical oscilloscope and current probes try to emulate that ideal situation.
When the diameter of the coax (again, in this example) becomes too large at the time scale of the measurement, we are crossing into waveguide territory, where we concentrate on the fields in the interior of the guide.  Note that waveguides can be built with dielectric walls instead of conductive walls, with well-defined (in conventional electrodynamic theory) results similar to conductive guides, with the possibility of having a large DC (or lower-frequency than the waves) voltage from one end to the other.  Similarly, if the interior of the waveguide is evacuated, one can run current in the form of electron or ion beams down the length of the guide, which will interact with the high-frequency fields.  As mentioned in someone else's textbook citation, at the frequencies where waveguides are common, the skin depth in the metal walls is very small, and the energy is transported mainly in the traveling wave down the guide.  With a bad termination, or a resonant cavity, energy can be stored in the standing wave.
There is a large literature and industrial history of both waveguides in general and particle accelerators in particular.  Again, they both work.
When Heaviside made his huge breakthrough (realizing that adding lumped inductors in series with the telegraph lines improved their bandwidth), he may have used the telegraph system grounding as the return (bandwidth is not so high with manual Morse code).  When AT&T successfully adopted his method to trunk telephone lines, they used twisted-pair transmission lines (balanced with respect to ground).
By the way, with respect to the outer insulation (jacket) on coaxial cables.  I have used precision coaxial cables, some of which had armored jackets to prevent damage, and coaxial cables with various dielectrics (usually PE or PTFE), and various jackets (usually PVC), but also "semi-rigid" coaxial cables, where the outer conductor is essentially a copper tube, with no outer insulation.  Careful use of these semi-rigid cables requires proper tooling for making bends, so as not to destroy the inner geometry.  See  https://www.pasternack.com/pages/Featured_Products/hand-formable-semi-rigid-cable-assemblies-up-to-18-ghz-new-from-pasternack.html?utm_campaign=usa_cable_assemblies&keyword=semi-rigid%20coaxial%20cable%20assemblies&gclid=eaiaiqobchmi2dv1-dzv9wivshrnch1uia-oeaayasaaegkoypd_bwe   for such assemblies available with or without outer insulating jacket.  Again, they work the same either way.