So, I genuinely do not get the "controversy" over the Veritasium video. AFAIU, the entire point of the video was to show that electricity travels not through wires but via electric fields ("through the air" so to speak).
To illustrate this, he sets up an experiment with parameters such that the conclusion can only mean that some electricity has traveled to the bulb before any could arrive through/around the wires.
He sets up the parameters so that the bulb would turn on by that little electricity; but that is obviously just a visual sign, and his point is valid no matter how much electricity traveled to bulb under whatever different parameters.
It kinda feels like most people are missing the actual point of the video.
1) Slander: He claims that the way EE is taught is a "lie" but leaves out the many ways that standard EE models agree with his result.
2) Clickbait / inadequate explanation: he leaves out many details in order to make his experiment seem far more mind-blowing that it really is.*
Critique 1 can be countered by saying he is targeting a lay audience (say, they took 1 high school physics course).
Critique 2 can be countered by saying he is targeting a slightly more advanced audience who would understand those details (say, 1 or 2 college courses).
But no matter who you think he's talking to, at least one of these critiques holds.
* In particular: a) He doesn't explain how "1/c" is derived from the 1m gap. b) He portrays the electrical field as totally detached from the layout of the wires. But if you rearrange his lightsecond-long wires to be a circle, the effect won't happen. c) He leaves out the fact that this experiment works even if you cut the ends of the wires, which would change many people's intuition (think of the wires more like antennas). d) His thought experiment is actually wrong: see Electroboom's video, but basically by Derek's own parameters the light would _always_ be turned on.
The problem is that his video is a mish-mash of two different concepts that were taught perfectly well in my freshman physics course. One is that the electric field travels down a wire at the speed of light while the electrons do not. The other is induced currents by moving charges.
I got the answer "wrong" by watching the video because I didn't consider the tiny amount of current induced in the other wire to be sufficient to turn on the light in any useful manner. If you had replaced the light with a sensitive ammeter and asked me what the first point in time there would be any measurable deflection from zero, then I would have gotten it correct.
Could have also just asked how this works, and the success rate would have gone way up (but he'd have lost all his clickbait):
This is exactly it. If being "right" or "wrong" about something involves subjective facts (is the lamp "lit" by the small amount of electricity induced by cosmic rays too?!?!) and trying to visually inspect an experiment you can't access in-person, then the only thing "wrong" is the video maker.
I'm not being snarky, the formula of his videos at the time was 1) Ask somebody in a public park a science question. 2) They get it wrong. 3) Explain why they're wrong. His thesis was about the supposed efficacy of this style of video (which he has since moved on from, to his credit.)
Much of electronic engineering is built around ‘lies’ - abstractions and simplifications because that makes sense in the vast majority of cases but are ‘wrong’ at some level.
You don’t need to use Maxwells equations or the underlying semiconductor physics equations when biasing a transistor, or calculating the output of a digital XOR gate because there are abstractions that are far simpler to use and work in just about all practical situations.
And of course those abstractions break down in thought experiments and beyond their limits in the same way that Newtons laws work up to a point and then you need Einstein.
Is this the same channel that made that credulous self-driving car video ad for money and passed it off as an educational video? Seems so: https://news.ycombinator.com/item?id=28949327
The thing is: this is sort of true. Now, all electrical engineers are very familiar with transmission line theory, that's pretty much their bread and butter. And all EEs know that if you're not working with well-defined transmission lines (like coaxial cables), you need to use a field solver. 2D field solvers are often sufficient, but if not 3D field solvers can and will be used.
And then most of those same EEs, despite having just used a field solver which clearly shows that all the power is in the fields, which are in the dielectric space between the conductors, persist in using the mental model that electrical power moves in wires.
This isn't just a pedantic quibble. There are real, practical effects. If you're designing a PCB and you have two signal lines with overlapping fields, those signals are going to couple, which will create common mode current, which will cause an EMI problem. You can stop those signals coupling by making them reference different ground planes, which makes the fields no longer overlap. If you route a signal line from one side of a ground plane to the other, you have to provide a path for the fields to get to the other side of the ground plane (i.e. "route" the dielectric, generally with a ground via), because if you don't, they will find their own path anyway and you won't like the results.
If you persist in thinking that electrical power flows through wires, these sorts of effects are mysterious and only explicable through the magical black box that is a field solver. If, on the other hand, your mental model is that electrical power is in the fields, then -- surprise! -- the results of a field solver won't be so mysterious any more.
And if you have a more accurate mental model, if you can predict more or less how the fields will behave before looking at the results of the field solver, then that means you can design with the fields in mind, rather than just tweaking things until the field solver stops being angry at you, but not actually understanding why the design works in the end.
I found the responses from other EEs on youtube like Electroboom and EEVBlog disappointing. You can quibble about details of how he presented it (like, saying 1/c rather than 1m/c), but Maxwell's equations are the correct description of how electricity works, and Veritasium is absolutely correct in his core point which is that power flows outside the wires. Other models, such as lumped-element and transmission lines can suffice for many purposes but are ultimately wrong. Rather than responding towards him with hostility, perhaps they should have considered if their own mental models weren't quite as accurate as they had thought.
As a final note, the problem as presented by Veritasium can't be accurately modeled by anything less than Maxwell's equations (i.e. a field solver), but you can get most of the way with transmission line theory and tweaking it with some physical common sense. Closing the switch causes electric and magnetic fields to propagate across the gap between the switch and the light bulb, and down the two transmission lines, at the speed of light (modified by the relative permittivity). The current that will initially flow across the light bulb, once the fields reach it, can be calculated from the characteristic impedance of two parallel wires acting as a transmission line. When the signals reach the end of the transmission lines, they will "see" a short and reflect with opposite voltage; when that opposite-voltage signal reaches the switch and light bulb the transmission lines act like a short and from that point on the light-bulb receives the full current. That 1m/c delay, in particular, isn't accounted for by transmission line theory at all. The way you get that (without a field solver) is by knowing that electrical power is in the fields, which propagate at the speed of light. Since transmission line theory can't accurately model the problem in full, I think Veritasium can be forgiven for not mentioning it (especially since he was targeting a general audience).
Is there really an epidemic of EE's who know how to use a field solver, but don't know to consider coupling between signal lines? My intuition is the opposite of yours: most EEs actually know the ideas from the Veritasium video. Therefore, the way EE is taught is not a lie, since it includes that knowledge.
(For completeness, the alternate take is that Veritasium was claiming "the way _elementary_ EE is taught is a lie" -- but that still leaves Veritasium having left out critical context for such an audience)
> I found the responses from other EEs on youtube like Electroboom and EEVBlog disappointing. [...] Rather than responding towards him with hostility, perhaps they should have considered if their own mental models weren't quite as accurate as they had thought.
Personally, I didn't get hostility from any of their videos. They were just injecting some engineering sensibility to bridge the gap between most people's EE knowledge and Derek saying "everything you've been taught is a lie."
Also, to my recollection they both absolutely attested that yes Maxwell's equations are the correct description which supports Derek's results (modulo Electroboom's callout about the bulb actually always being on)
> Is there really an epidemic of EE's who know how to use a field solver, but don't know to consider coupling between signal lines?
Now, I'm not an EE myself, just someone who took undergraduate electrodynamics, decided to read up the subject, and found some truly excellent videos on youtube.
> I spend most of my consulting time solving EMI problems because
most of the engineers I meet have no clue about any of this. My
job is so easy and I make such a ridiculous amount of money doing
it. It's just unbelievable; I solve most EMI problems by simply
adding returned vias to boards or changing the positions of
decoupling caps, I mean the things are so simple and ridiculous
it's amazing and if these guys would educate themselves they
wouldn't need to hire me.
So I gather that there is a problem. It's not that EEs don't know to consider coupling between signal lines, but because most of them persist in thinking that signals travel in wires, rather than in the fields, they don't understand when coupling will occur and when it won't. Sure, they can look at the result of the field solver and realize they have a problem, but without thinking in terms of fields they don't know how to solve it. So, they fix it either with trial-and-error until the field solver is happy, or by following design patterns that are passed down as an oral tradition, but without actually understanding why it works or what the problem was in the first place.
That's simple to understand if you think in terms of fields. Even worse, if you have signal lines that are parallel and on top of one another (on different planes), referencing the same ground plane from the same side, then it doesn't matter how far apart those planes are, they're going to couple strongly since the fields overlap. You can have two traces right next to each other that have virtually zero coupling because they're stripline, or, if you have a stackup with a single ground plane on the bottom layer, a signal line on top of that, and a signal line on layer one parallel and on top of the bottom trace, they're virtually on opposite sides of the board and yet they'll couple strongly. And if you don't think in terms of fields, you'll observe that, whether in simulation or on a circuit board, and have no idea why it happens or how to fix it.
Here's Rick talking about the state of the industry in the 1980s and 1990s: https://youtu.be/ZYUYOXmo9UU?t=4295. It's clear that no, EEs weren't taught this, they didn't understand it. The situation has, I believe, improved somewhat, but only perhaps in the last decade or two. I would guess that even today, most EEs still don't really understand this (or Rick wouldn't be making so much money consulting).
> Personally, I didn't get hostility from any of their videos.
Perhaps "hostility" is the wrong word. I think on reflection "dismissiveness" is better.
Like, "Yes, we know that Maxwell's Equations are the ground truth. We were all taught that and understand it. But that's not the way practicing engineers work -- we use models like transmission lines and lumped-element. It's technically correct, but more of a curiosity than anything. It's not something we really need to think about, and certainly not useful for a general audience -- more likely to confuse them than anything."
That's the general impression I got. And I think, that not only was Veritasium technically correct, but that model is useful, and most EEs don't use it when they probably should.
Most of us here on hn are software developers. I think that most would probably agree that on the whole, we're all pretty terrible at it. Why would you think Electrical Engineering would be different? Because they're "real" engineers, whereas we just sometimes call ourselves "software engineers" (knowing that's pretty much a lie)?
Here's a presentation by Eric Bogatin that reminded me more than a little of the sort of cargo-cult design patterns that pervade software engineering: https://www.youtube.com/watch?v=y4REmZlE7Jg
I think you're correct for the most part. I think us EEs tend to compartmentalize the information we've learned in school; while we may technically have all the "tools", knowing when to apply that knowledge isn't always apparent.
I definitely think there is a lack of applied EE knowledge; PCB layout with an emphasis on signal integrity etc would make an excellent undergrad course in school.
In terms of PCB layout -- Eric & Rick have been absolute goldmines in terms of the knowledge they've put out there. I can also say that both of the FAANG companies I worked with sent us EEs to their training seminars, which were super useful (and shows that there is recognition in the industry that EEs need better training on these sorts of issues). I also think there is a bit of an art to it -- you learn when layout issues are significant or not, and can identify them by eye. This is something you learn by experience. For me, I've found field solvers are a great way to validate / hone my intuition.
> PCB layout with an emphasis on signal integrity etc would make an excellent undergrad course in school.
This is strongly frequency and wave-form dependent. Just the difference between square waves and sine waves and say a few KHz to a few 10's of MHz can have dramatic consequences on how hard it will be to get a circuit to behave in the way you intended it to.
I think one of the bigger insights you can have when designing circuitry is that you may be working on a digital circuit but from an electrical engineering point of view digital simply doesn't exist, that's just a signalling convention, there is only analog.
I think it was in one of Rick Hartley's videos that he talked about designing for analog vs digital. There are a bunch of points I remember, in no particular order:
- the frequency of your circuit, that you need to design for, is determined by the rise and fall time of your ICs, not your clock. (With your square wave, for example, it's impossible for it to actually be square; it has some finite rise and fall time that determines the frequency you need to design to).
- IC manufacturers almost never actually tell you the rise and fall time of their chips. Also, they might do a die shrink at any time, resulting in you having to redesign your circuit to accommodate the higher frequencies from smaller, faster transistors (even if it operates at exactly the same clock frequency as before). If you're lucky, they'll even tell you about the die shrink rather than just letting you find out when suddenly your design stops passing EMI testing.
- high-frequency can be easier than low-frequency; you really need to pay attention to impedance control, but so long as everything is well laid-out the fields will stay closely contained. The lower the frequency, the more the fields will spread and the greater the risk of having problems such as crosstalk.
- Digital is easier than analog. Digital can tolerate a lot of noise before a 0 becomes a 1 or vice versa. Whereas if you're sending a signal to a 24-bit ADC, you might have to go a bit crazy and use a PCB-embedded waveguide, or something, to give it the isolation it needs.
- Even if digital signals are quite resilient from a signal integrity standpoint, you still have to pay close attention to crosstalk because it takes very little common mode current to cause an EMI problem. And you have to pay attention to EMI if you actually want your design to pass emissions testing to be able to sell it.
- Even at high frequencies, anything at a length scale less than (wavelength of maximum frequency)/10 can be treated as a lumped element. So if it's possible to jam two high-frequency ICs right up against one another, with the pads pretty much touching, that's probably actually better than a carefully impedance-controlled transmission line connecting them. That's not really applicable to some monster BGA chip, but if you're designing a switched-mode power supply you can make the node between the inductor and MOSFET a lumped element by placing them as close as possible.
EEs tend to be pretty practical in the same sense that mechanical engineers are pretty practical: they build stuff in ways that they (think they) understand to give them as good a chance as producing something that works the first time around. But the devil is in the details and mechanical engineers have one huge advantage: they deal with stuff at a scale where getting it wrong will have visible consequences. An electrical engineer getting their assumptions about electric fields emanation wrong is going to have a difficult problem to solve, electric fields don't readily visualize and without a very solid understanding of the theory it is extremely easy to mess this up. This is one reason why people tend to be conservative, if you do it 'like it is usually done' then the chances of discovering new and potentially expensive ways to mess it up go down a bit.
I once - long ago - rebuilt a transmitter that I had designed using 'regular' components in the air on a circuit board. It took 6 tries to get it perfect, and every time I learned about a new assumption that wasn't exactly spelled out anywhere but that really made a huge difference in how the circuit operated.
The electrical schematic was identical every time, the only thing that changed was the topology in space. And the difference between iteration #1 and iteration #6 from a performance point of view was huge, much larger than you would have ever thought could be the consequence of the very subtle changes to the various trace geometries.
No matter how much you know - or don't know - about the way electrical fields interact with each other be prepared to be surprised, this stuff is simply hard when your circuitry goes beyond a minimum level of complexity.
Interesting tidbit: many years later when designing the windmill stator/rotor/coil assembly some of this knowledge came in quite handy.
Did you perhaps mean you changed the geometry instead of topology? Your comment got me wondering if you can change the topology without changing the schematics and I now think you can, as a schematic only defines the electrical connections and the topology is I think also the non electrical relations (what component is next to what). As far as I know topology is strictly dimensionless; size and distance are properties of the geometry. If I were not on HN I would apologise for the pedantry, but here we are
There's nothing deficient about transmission lines or lumped element models for answering the riddle. Distributed element models of transmission lines [1] clearly show a straight line path directly from the battery to the bulb without going through the whole wire.
Electroboom's criticism is that even if you're not misdirected by the setup, there's still a missing assumption required to arrive at the same answer as Veritasium.
In the case of a circle, you should still have a radiated signal that arrives before the conducted signal. But it would be far weaker, further compounding the problems with the "light bulb illuminating" way of illustrating that a signal has arrived. In the original experimental design, it was already reckless at best to leave the viewer with the impression that the radiated signal was capable of powering the light bulb rather than merely serving as a trigger for a self-powered light. With a circular setup, I doubt that equipment sensitive enough to detect the arriving radiated signal (and reliably distinguish it from other electromagnetic noise) could even fit into the light bulb's black box.
Veritasium's video got my only down-vote of the year because he gave the wrong picture to people.
At first order the bulk of the energy follow the wire like a train on its rails.
Sure you could put a windmill turbine one meter next to the train and the wind from the train passing will make it turn immediately, but no one would argue about that the wind carry most of the energy.
It works this way because the electrons are stuck on the wire like a train is stuck on its rails. The Electro-Magnetic field on the other hand like the wind is free to permeate space. What is important to understand is that electrons and EM-field are two-distinct things that are coupled together.
Derek's video tried to explain transmission line theory, but didn't do the experiment while making grandiose claims about a fictional setup. Kudos to alpha phoenix for doing the experiment.
Given that Derek recently created multiple "debate" videos, and that he is more interested in the way to teach Science and how to reach a lot of people than by Science itself, it feels like he probably has engineered this controversy himself for views as a meta-experiment.
A lot of video responses from unknown youtubers show a better understanding than the original.
For example you can see a numerical simulation of the electro magnetic fields (with Ansys) https://youtu.be/aqBDFO1bEs8?t=364 that show how electricity move (the separation distance between the wire there is only a few centimeters).
The problem though is interesting if you try to understand how exactly the energy transfer is happening : Is it capacitive coupling, Is it inductive coupling, Is it EM radiation ? Which one exactly is the dominant term ? Where exactly are the electrons ? How are the electrons interacting with the field ? How can you shield it to isolate and show the various effects (magnetic shielding, electrical shielding) ?
I think the controversy is because that while being technically correct (bar a couple of mistakes) there are two main issues:
1) To get the result presented heavily depends on the experimental setup and this appears to be hand-waved away (or for the cynics: deliberately obscured) as it would detract from the impact of the video.
2) The definition of "ON" in the video is not what anybody would reasonably define as "ON". This is not discussed in the video therefore potentially comes of as deceptive.
As an electronic engineer I actually initially found the video confusing. I wasn't familiar with Veritasium before and I will admit my initial visceral reaction was "Oh he's just one of THOSE YouTube's and needs his clicks".
It wasn't until I went back through to understand Veritasium's unspoken assumptions, simplifications and a couple of medium mistakes that I could say: yes this is technically correct.
Personally I think with some better choice of wording the pitchforks wouldn't have come out as they have.
I still don't buy "then yes this is correct". If "ON" is defined as a state where ANY electromagnetic field flows into the lightbulb, then it is "ON" even before you throw the switch, because other photons are already shooting around all over the place, including from the neurons in your body pondering the result just before you throw the switch.
The definition of "ON" is exactly the main controversy with this and not a subtle detail.
Even if we also accept the unspoken assumption that there are no other photons/electrical fields outside the experiment, the experiment is still wrong, since the battery will produce a teeny tiny electrical field even if the switch is off. This is much more visible if we assume the switch is at one end of the light-second long cables - throwing the switch has little impact on the experiment as explained.
Yes but that does not generate clicks,views and that sweet youtube money.Sorry but I cannot stand those kind of guys (he, Mark Robber and the likes). Khan academy is doing something 1000000 times more valuable.
His technical errors include the “correct” multiple-choice answer being that the time to turn on is “1/c s”. That evaluates to 3.3e-9 s^2/m. It’s not even a time. Failing basic dimensional analysis is grossly sloppy.
The correct units would have tipped his hand and led people to realize the 1m separation of the wires is relevant and thus people would reconsider antenna approaches. That would blunt the gotcha effect.
It should be obvious that the "c" here was used as a magnitude not with units. Saying that's "failing dimensional analysis" is in itself grossly sloppy - since it totally misses the context.
But dimensioned quantities are meaningless without units. are you saying c has a value of 1.803e+12? Or that it has a value of 1? There’s a big difference between using furlongs per fortnight and speed of light as your units for speed. By saying “1/c s” rather than “1 m/c” he was just plain wrong and certainly in no position to be smug about it.
That’s like being a grammar Nazi even when someone writes something otherwise totally clear.
And it’s obvious in this case that the magnitude of c was in metric units.
And how do you know if he was even referring to the speed of light by “c”? I could call that a dumb assumption. Because it’s obvious he was using it in a non standard way “magnitude of the speed of light in m/s”.
In my opinion the video made a couple of mistakes, which I think ElectroBoom's response* addresses nicely.
Also its proof using the pointing vector to show the flow of energy is misleading; In the video Derek shows that the energy flows toward the lamp when the circuit is already in a stable configuration, but the point of the video is to explore what happens before the circuit reaches that configuration.
This is relevant: assume that the right half of the cable is connected to the positive pole of the battery, in a stable configuration every point of the right half of the circuit has a positive charge (creating the poynting vector field as shown in the video) while 1/c seconds after the switch was closed the wire just to the right of the lightbulb will have a negative charge (the cable near it is positively charged from the battery and so the upper cable acts as a the negative half of a capacitor) which changes the direction of the poynting vector.
In the end it felt like it was telling you that its message was that energy travels via the fields but what it actually said what that switches cause electric interference.
I think "the point is being missed" in the Veritasium video, because it is obscured. It's obscured to increase the "gotcha and unintuitivity factor". Veritasium more or less makes it sound like all the interesting parts of the circuit goes through the direct line-of-sight path between the battery and the light bulb, and ignores the wire. Which is misleading.
Derek would not have written tweets like this one, if his video had been more direct about what he was talking about:
I think the key part of the controversy is the word "some".
In the original Veritasium video it pretty strongly implies that enough energy to light the bulb, i.e. virtually all the electricity, is traveling instantaneously a short distance rather than "through" the wire.
A big part of that video is to essentially say you're wrong if you understand electrons moving through the wire as how electricity works.
The video posted here tells a different story which is essentially that the mental model of electrons flowing isn't that far off, but there is a bit of nuance when you take into account fields.
This is sort of a persistent problem with "edutainment". I generally enjoy Veritasium, but this is clearly a case where the education component is weakened in order to increase the "wow!" factor of the video.
This is an oversimplification as well though, because the model for current flow is exactly based on moving electrons and that works just fine to predict results.
The battery in the experiment is explicitly based on chemistry which is exactly described as electrons being moved around.
It mostly works that way, but not exclusively: the moving electrons in one circuit create an electro-magnetic field that can induce currents in other nearby conductors that are not part of the same circuit.
If electricity doesn't travel through wires, why do resistors dissipate heat?
I'm having trouble understanding what is even being claimed. Electrons are moving, without the movement of the electrons there is no electricity travel, without the wires there is no flow of electrons, so what does it mean to say that electricity doesn't travel through wires?
Is the claim just that the electricity, by way of fields, travels at a rate much faster than the electrons themselves are traveling? That seems like a reasonable claim. But "electricity doesn't travel through wires" seems rather suspect.
The video seems to make a point that is entirely wrong: that (all/most) energy in a circuit travels directly between the source and the power sinks.
Now, if you follow it carefully, it makes a different point, that is actually correct: it actually claims that some energy travels this way, since the electric field is not strictly bound to the wires, some part of it radiates out.
What the video is sorely missing is a discussion of the intensity of that field, which is going to be extremely low even 1m away from the wires, for typical batteries. These effects are absolutely important though in high power cases, where even a small fraction of the energy carried along the wire leaking to nearby wires still means you can actually light a lightbulb (or burn many other things).
This is the best demonstration of EM fields I've seen. It kinda demonstrates what Derek was going for, but with resonant antennas the power transfer is way more that his theoretical setup.
"Friction". Mechanically, electrons in a metal conductor behave something like a glass bead in honey. Observe that the microscopic Ohm's law says that the velocity is _proportional_ to the force being applied, the electrons do not accelerate as they would in a uniform electric field in vacuum.
> so what does it mean to say that electricity doesn't travel through wires?
I think it’s specifically that the energy flux has a well-defined vector at every point in an electromagnetic field, and those vectors do not point along the wires.
> It kinda feels like most people are missing the actual point of the video.
I love his videos, but the reason most people are missing the point is because he only obliquely hits the point. The title and thumb are the clickbaitiest he's ever done, and the content does a wide end-run around the facts, rather than tackling them head on. This is also why there are so many rebuttal videos that agree with him and explain it more clearly: he failed to clearly state his argument/explanation. The circumlocutious explanation does little to edify the audience or clarify the concept.
He sets up the parameters so that the bulb would turn on by that little electricity
That's the bit where he's factually wrong. He's made this illogical world where the tiny amounts of electricity in field lines well outside the wire trigger the lamp but the leakage current and other sources of current don't. If you're going to be pedantic about something you have to be pedantic about the whole thing, damn it. Veritasium's video is like saying "water flowing through pipes is a LIE" because some molecules of water make it through the various seals and diffuse across the outer surface of the pipe.
The experiment can be made to work (light bulb actually lighting up ~instantly at a significant brightness), just not with a 12 V bulb.
> Veritasium's video is like saying "water flowing through pipes is a LIE" because some molecules of water make it through the various seals and diffuse across the outer surface of the pipe.
- it’s not the length of the wire, it’s the distance between power source and consume that determines how fast power travels (how does power “know” where to go, if not following the wire?)
- since power travels outside the wire, it should be okay not to plug in the power consumer.
I’m pretty sure that’s completely and utterly wrong, but I don’t know what he is trying to say. So the video creates more confusion than it clears up.
> It kinda feels like most people are missing the actual point of the video.
Which raises an age old philosophical question about communication: who’s at fault for the misunderstanding: The sender or the receiver?
I’d say it’s a bad video because it is from a trusted source of science and most people misunderstand it.
My limited understanding, according to Veritasium, is that the wire is needed to create the electro-magnetic field. Veritasium's claim is the distance of the wire is irrelevant. It's the distance between the battery (power source) and bulb (resistance) is what is relevant. AlphaPhoenix is disputing that claim saying there is a lightspeed electron "wave" through the wires.
I think this is the most fascinating debate on social media currently.
Among EEs that I've seen there are only really three points of controversy: the "any current at all turns the bulb on" bit which he didn't mention in the initial pre-video quiz (but which is super important), that he missed the unit of meters in the `1/c seconds` answer (it should be `1m/c seconds`), and (for the pedants & puzzle solvers) that he ignored the interesting bits about steady state behavior.
Nothing (except forgetting the units of meters) he said is wrong. It's just a bit uncharacteristic that the video didn't match the initial quiz, and it ignores some of the most interesting bits of the behavior. But it wasn't targeted at EEs who are already familiar with the "simple" transmission line behavior, it was targeted at people who haven't ever learned or dealt with that. So the steady-state behavior would have distracted from the focus of the video IMO.
There's also the problem of the switch: Derek's arguments still work for the circuit with the switch still off, since the battery doesn't stop producing an electric field just because the switch is off.
The way he describes it implies a speed-of-light violation! He's setting up a scenario where he can transfer information (by ON/OFF of a light) at 1/c.
That's the controversy. It's great that he found a fun way to explain transmission theory and how wires are effectively antennas, but he's taking the same thing he initially calls out (how the general understanding most of us have is a lie) and making it even worse in another direction.
Anecdotally, as a novice, I was left really confused by Veritasium’s video, whereas after watching this video I feel (hopefully accurately) like I basically understand the situation. If people are missing the point of Veritasium’s video, maybe that’s because it didn’t make its point very clearly…
I think the confusion is that Veratisium's original video made it seem like this was the only/main way electricity travels, whereas in reality, there's two separate ways: One of them take's 1/c and the other takes c/2. Also, what most people think of the light bulb going on in the real world would be the c/2 one, not the 1/c one.
The controversy is that it twists the standard definition of "on": the video boldly asserts its shocking answer of 1/d at first, only later to admit (with very little clarity) that the 1/d answer is only true if your definition of "on" is a small electromagnetic spike.
This also means that the "misconception" claim is really just click-bait and really there was never any misconception.
Not answering your questions but I am so glad this "controversy" exists. I've learned so much more about this topic from all these response videos than I could have if there was no controversy.
What confused me is that the effect does not actually require the circuit to go through the resistor/lightbulb. Instead of thinking in terms of a delay, you could just have the switch and power supply in their own closed circuit, and the resistor alone with maybe an antenna to boost the effect.
> AFAIU, the entire point of the video was to show that electricity travels not through wires but via electric fields ("through the air" so to speak).
Only that he doesn't context the video with that, But with a 'trick/googly' question. One of the reasonable constructive criticism I came across for this video is from Mehdi(ElectroBOOM)[1] where he explains why the real answer is not in the options offered by Derrick.
Personally I like the quality of Veritasium videos, but I lately feel that the barometer has shifted towards sensationalism rather than scientific education.
To illustrate this, he sets up an experiment with parameters such that the conclusion can only mean that some electricity has traveled to the bulb before any could arrive through/around the wires.
He sets up the parameters so that the bulb would turn on by that little electricity; but that is obviously just a visual sign, and his point is valid no matter how much electricity traveled to bulb under whatever different parameters.
It kinda feels like most people are missing the actual point of the video.