Thank you for making this video! While in hindsight I can clearly see that I should have gone into more detail with the explanation, I have really enjoyed watching all the response videos. For the record I was not suggesting the lightbulb lights at ANY current value but at some small but significant current value. I tested my LED bulb rated for 12V and found it turns on dimly when I apply 2V. There may yet be a follow up video coming. So thank you for this commentary - I'll incorporate it into any further work I do on this topic.
isn't any current that turns the bulb on "significant"? ;) also i doubt that'll change the fact your wires aren't magic warp machines. as soon as your current is significant enough as to not have the lamp on all the time due to background noise, your EM coupling between the "half-loops" won't suffice, while the transmission along the loops will take its time.
Thanks for the shout-out, Mehdi! This was a thorough and nuanced response to Derek's video. It's important to remember that, while the energy _is_ transferred by the fields, the current is still in control. The lightbulb isn't going to do _anything_ if there isn't a current through it. During a recent live Q&A (for supporters only), I talked about Derek's question a little. My guess was that a real-life bulb wouldn't immediately turn on, but would slowly/gradually brighten over a few seconds. It sounds like you agree, which is validating.
The funny thing is that with 10m of distance, you already have a super small current from the capacitance alone. The only correct answer, the lamp is already on, so its 0s , not matter if you close the switch or not. Oh the leak current, about about the leak current... That was my conclusion while I watched the video, baffled. Doesn't electric fields technically go to infinity ? even thou they decrease with the square of the distance ? All lamps are always on by veritassium definition.
Another thing that irritates is that it was never defined what is a "turned on lamp", one would presume it would emit enough lumens, but how much ? What are you ideas on this ?
Thought to mention, even the 1 second round trip delay is not fully accurate as the LC circuit imposes its own propagation delay on top of light speed. Like I said the current flattens out traveling through the network and that slows down voltage step transitions, as you also see in the simulations at the end of video. Sorry, too much technical details!!
I've begun my journey into electrical engineering as a hobby thanks to creators like you. I began watching because you were purely entertaining, and now I'm accumulating tools and measuring current and actually sat down and measured hundreds of resistors the other day and was actually excited as I thought about how it all works. I'm slowly beginning to understand more and more about how electrons move and how various components can manipulate them into doing all kinds of cool stuff. This video helped me better understand that movement. Thanks for making such great videos!
I find that really cool kind of like me but but with me it was more of going to the ocean and being intrigued by the water I've been to the ocean many times but this time it did something to me and since I went 2 weeks ago I've been doing nothing but researching oceans and bodies of water all throughout California I even love going on Google maps and just looking at bodies of water and trying to get a street view being in the ocean and the lakes and rivers terrifies me but I'm also very fascinated with it. I wish that I could find a way to go into like what you are doing if there was a way to accumulate tools or somehow get into marine biology but I hear it's such a hard field to get a job in. Idk LOL just yappin
Finally an engineer that combines both the engineering and physic models without outright dismissing one or the other. A very insightful video that perfectly complements Derek’s video and add some much needed realism to it. If I could subscribe twice I would!
@Idiosarchy I think the video is still complementary because it's a thought experiment designed to emphasize a specific mechanism of electricity at the exclusion of all others. Maybe he could have been more thorough with his hypothetical situation, but I don't think it's fair to say it's wrong or misleading. If it was meant to be purely realistic he wouldn't have said the wires have zero resistance or that the lightbulb would turn on at any amount of current. I guess he did sensationalize it with his choice of words, but it's RUclips, of course he did. Is this channel any different in that regard?
@Idiosarchy The basic concept is not wrong. It really will take only 1/c seconds for a change in current to start happening through the light bulb. Derek's thought experiment has some flaws (he could have been more detailed and specific). Just like Medhi's thought experiment has some flaws (which he points out). No thought experiment is perfect, but it doesn't need to be in order to communicate the basic concept. The basic concept is 100% correct.
You do realize that Physics has branches and that those branches also have branches? Physics is like the tree with, for example, the branch Circuit Analysis. You can also split your Classical Mechanics into Statics and Dynamics. You can split your Fluid Mechanics into say Fluid Dynamics. Don’t even get me started with Metaphysics. Good times, haha 😂.
@Idiosarchy the argument obviously has flaws, I never denied that. My point is that he hilights a physical phenomenon that we can understand even if the thought experiment is imperfect. At this point we are just splitting hairs even though I think we both understand the point and intent of the message. I'd like to point out that Schrodinger's cat also probably would not actually work in real life but emphasizes the strangeness of quantum mechanics in a way that is digestible to the lay person. The point is to isolate variables, not to turn sci-fi into reality
This is a perfect example of the value and importance of readily accessible rebuttals to all content online. Rebuttals add value to the discussion and people are better off when they get critical responses from other people who add nuance and further context to issues. We need 'The Socratic Web'...
I love that you, electroboom, bigclive and other electrical channels have something to say about this. It's very interesting and I don't actually believe everything he said although I know I'm far naive. I loved electricity ever since I existed but I still have no complete understanding of it. Still, thank you electrical community! Kind of funny he predicted that it he would be called out but turned out he was called out because of the simple answer itself. I'm just waiting for Derek's reaction to this. He seem to be very sensational in his videos and inaccurate.
SCHOOL! The answer is I don't go! Why go? I am famous. I am famous. I have more fans than fingers multiplied with toes multiplied with teeth multiplied with ears. I am famous. I am famous. SCHOOL? No, thanks. RUclips FAME? Yes. Good day, dear eev
Hi, can any of you please explain this in terms of high school physics? What we have learnt is that current travels through two methods - conduction and induction. What I understood from Derek's video was that he was claiming that the bulb would turn on simply by induction field from the battery. The conduction field as I understand travels through the entire length of wire before hitting the bulb. And the induction field would be too weak to turn on the bulb. Kindly elaborate on this. Also, I saw a video where the person said that if he places the switch near moon, as soon as he closes it, then by Derek's theory, it would turn on in 1/c seconds. So by turning the switch on and off, he could essentially send a Morse code message from a distance of c metres which Derek can receive in 1/c seconds, esentially violating that no information can be sent faster than c theory. It would be very kind if you could explain that as well.
I am the Abbott you mentioned in your video. I did the initial simulations and built a scale model for verification. I loved your explanation and gained a lot more insight from the clear way you explained it. I think Derek did a great job of getting people thinking about all this, and I'm delighted you are the one who actually took the time to verify my result as I didn't think anyone looked at it! Thanks again, I just subscribed to your channel.
Poynting theorem states that closed surface integral of E×H = rate of decrese of energy stored by electric field and magnetic field in the volume of closed surface minus the ohmic losses Ohmic losses depends on the conductivity so simply I can say that power flowing out if any closed surface integral of E×H Now in above case (DC)since magnetic field set up by DC current is constant so as the electric field. So there is no there is no propagation of E and H outside the wire... It is just a set up of E and H. The stored energy due to electric and magnetic field outside the wire is not changing with time Sooooo..... Poynting theorem only depends upon conductivity. Since the conductivity of the medium outside the wire is zero ,,so it will not propagate outside the wire.... Derek is only looking at E × H in this video actually E× H is not propagating in case of DC According to him he can transmit energy wirelessly at 0 hz. Moreover he is right that current flow and energy flow are not in the same direction..... In case of AC you can transmit t using the above concept but then again you need some waveguide for the energy flow.
The Veritasium video feels analogous to saying "In a hydraulic system It's the pressure waves which transmit force, not the water molecules" which is technically true but you can't have water pressure without, you know, the water molecules. Granted a hydraulic system is far less complicated than an electrical one (there's no induction for one) but I still feel that is a fair comparison.
The most important difference being that water molecules*, unlike charges, can’t act on each other at a distance at relativistic speeds. I think it’s a fair comparison, and it poynts to a potential issue with Derek’s interpretation. He acts as if the EM-field is the be-all and end-all of electricity. When it’s the charges and their acceleration and velocity that defines the EM-field in the first place. * Water might not be the best example when I think about it, as it's a polar molecule.
@@Triszious I mean the water molecules kinda do still have those electrical properties. Electrostatics mean when we think about the water molecules colliding they don't actually collide they bounce off each other's charges ;-) so you're more right if you wanted to get silly about it (like the veritasium video)
Could you think of the size of the pipe with water running at a certain speed carrying some momentum as analogous to induction? The water hammer effect seems to be very similar to the flyback voltage spikes.
This was the exact reaction I got from my father who is an electrical engineer. The point of the video was really just to show that energy doesn't just flow like water in a pipe, but the question posed in the beginning really was quite a misleading
Funny thing is - you can transfer same "energy" in a pipe as a fast cold water flow OR with a signlificantly slower flow of hot water. And the slow but hot water will actually radiate the energy similarly to a magnetic field
Misleading to say the least. I really really like how medy brought in an even more interesting and crazier answer with leakage current. This video was awesome. I am also in EE. and i was also very very triggered by Derek. I agree with Medy!!
Indeed. As an educational video, Derek did a really bad job. Actually causing more confusion and misunderstanding. Giving people the impression that ALL electric energy flows straight through the air. When in fact the vast majority of the energy flows inside the wire, or very close to the wire. Only a tiny fraction of the energy flows through the air any meaningful distance from the wire.
Viewing EM fields from the perspective of energy carried is just straight-up confusing to people, who don't understand where the concept of energy even comes from And these people are the vast majority
"Energy", the physics term, and energy as it's commonly defined are two separate concepts. "Energy" in physics lacks physicality. You can't point to energy, and it is reference dependent. That's the whole issue with Derek's question. "Energy" doesn't exist, it's a description of emergent properties within a system.
I must say... well done! Very concise considering the topic. More than anything else, I am proud and excited that this level of technical discussion is happening with millions of people tuning in to watch.
This is the modern-day equivalent of scientists and philosophers debating on stage with the public watching. We also have popcorn emoji now 🍿. Great times we live in.
Indeed, it make RUclips more valuable. THX for that guys. P.S.: In Germany it is an kind of meme or insult when you have an discussion and someone say "have you learn this on RUclips university?"... For sure - on RUclips it lot of crap to see but for my understanding there is lot more of thoroughly elaborated articles that are scientifically proven. It drives me crazy that people are unable to tell what is bullshit and what is true... Common sense and some general knowledge and, on top of that, some research are usually sufficient to check the difference.
This is one of the best videos I have watched in a very long time. As an engineer, I think, this is exactly "how" and "what" we need to teach upcoming engineers. Very well done. You have a subscriber. Thank you and keep it up.
With regards to the “lies” point, I’m reminded of something my engineering professors at university would sometimes say. All models of the world and its behaviour are wrong, but some of them are still useful.
A model are accurate to a certain scale, then at another scale a different model will explain things better. eg: the Newtonian gravity is accurate at low gravity condition but not at high-gravity, while Einstein spacetime curvature is accurate at high-gravity condition. A model is functional at specific scale & conditions and it is against our common sense to even call the Newtonian gravity "wrong" just because there exist a different explanation like spacetime curvature.
ie. Almost all but the most detailed fluid dynamics relations. Several of the are true, but exist in simplifications that cannot exist irl. or they are simplifications that intentionally get something wrong, because the question is impossible to solve otherwise. Still the best solution we have, wherever dimensional analysis and models aren't feasible.
I took it as "lies" we tell children so we could help explain better a concept without needing for the kid to do a psychics/engineering course so they can grasp at it.
These guys are the real reason that still RUclips got some value and the amount of knowledge they bring out here is simply immense and I hope many people are getting benefited by these kind of videos and a huge kudos to such content creaters love you all.
As a complete layman and after seeing Veritasium's second video I think I finally understood the issue. You both came to the same conclusion, except that Mehdi clarified how the details of this thought experiment were important. Derek's description of electric fields is true but it is presented as if the fully complete circuit is inconsequential. It is important that the completed circuit wires guide the electric field in order to have a light bulb fully light up, which takes a year for a lightyear-long wire. The "disconnected" parallel wires which are 1 meter apart will cause an "immediate" (1/C sec) voltage increase in the light bulb when it is connected to power, because a small amount of energy is transmitted across the 1 meter gap. However, whether the light actually turns on from this depends on the required voltage (e.g. an LED requires less than an incandescent bulb) which in the case of an LED will only dimly light up and you have to wait for the energy to be transmitted across the complete circuit before it fully lights up. Therefore, no laws of physics were broken because none of the energy was transmitted faster than the speed of light, so our conventional abstraction of how electricity "flows" still illustrates the important parts of how electricity behaves, even if it's not a complete picture. The impression I got from the first Veritasium video was that this model is completely flawed. Did I get all that right?
So in Derek's experiment the distance between the lines was set at 1 meter. What would happen is the entire 300k kilometers of wire was laid out in a perfect circle. Hmmm....
@@BillAnt It would take the circle's diameter/c to get that first small bit of current, then it would take the circle's circumference/c to get the full voltage.
What really bugs me is that Derek calls other models "Lies".. i think that violates a very important principle of science, that all models that are supported by experiment are equally correct. It's like calling one of the many theories of quantum mechanics "lies".. it's just a different way of thinking about the same phenomenon
100% agreed, veritasium really annoys me hes become the epitome of pop science when he used to make pretty good videos. I know hes just playing to the algorithm but i feel like his style makes you loose so much nuance.
@@Thisisahandle701 No. Derek does not get credit for making a bullshit video that happened to lead to good discussions when other more responsible and knowledgeable people had to correct and clean up his mess.
Well, he's been taking lots of notes from Mr Beast's notebook for the last couple of years, so obviously feeding the algorithm first and the conversation second was in the cards
The biggest mistake in that video is him saying schools LIED to us. If schools teach something that seems wrong, that's because it is oversimplified for us as young students to understand. That is not LYING. Derek is an educator and his role is to clear up the misconceptions. Leave the lies to conspiracy theorists.
@@FootLettuce I saw a Kurzgesagt video earlier that used the word "lied" in the exact same sense (that oversimplification is lying), and I thought that was unnecessarily clickbaity for the same reasons.
I just realized, these videos are the equivalent of scientists/mathematicians dueling during the olden times. Back then they used letters to communicate with each other, trying to question/disprove the other's claims, or battle it out in a good old duel. Now we are seeing it happen but 21st century style!
I remember an experiment I did during my masters thesis. I was attempting to make a lidar based on Time of Flight and had acquired a chip (which I don't know the name of right now) that could measure time extremely precisely (we're talking down to sub 100 ps). I had a microcontroller generating a start and a stop pulse (at some frequency I don't remember, but it was on the order of magnitude of 1Hz), then I measured the difference between the propagation time of the signals. I don't remember exactly what the input into the timer IC looked like, but I assume it's some sort of MOSFET gate. Anyway, I tried with different lengths of wire and could indeed measure the lengths with the propagation time (cool!). I also happened to have a 100m roll of wire I just bought, so I tried connecting it to see if they really did provide me with the correct length. I was very surprised when the propagation time was way less than what would be expected from that 100m wire. My thoughts was that either I found a waay to send information faster than light and should clearly be awarded with a Nobel Prize... or that there was some other effect I didn't fully understand. Most likely this was some combination of infuctance and capacitance in the wire (since it was basically a coil). We could also change the propagation time by moving our hands closer to the wire coil. So yeah, Veritasium is right that currents don't flow ONLY in wires, but the matter is more complex. Thanks for the good explanation, Mehdi!
> currents don't flow ONLY in wires Currents *do* only flow in wires. It's the "voltages" that can span matter / space, and induce currents in other parts of the circuit.
If it’s not too much trouble, what chip did you use? I was wanting to make a TOF lidar range finder but I couldn’t find any MCUs with fast enough timers
That's because many people fail to fundamentally understand their electricity and magnetism classes. Induced current is just as important (and dangerous to screw up) as the direct path current. There is a reason if you take electricity and magnetism, signal analysis, and signal transmission, you will hate the designs from most engineers.
@@SDX2000 it is the EMF. To quote my college electronics teacher, "in relation to what" is the most important aspect to voltages. Voltage is a massive simplification of the complex effect of EMF.
Micrchip developer here: thank you very much for this video. Whilst to most of the people discussing this, the 300.000km wire with a Lamp is a hypothetical - we microchip developers deal with "lamps" that turn on and off in fractions of nanoseconds; a speed at which centimeters are like 300.000km to a lamp - and at which the reflections and slew rates described in your video are a well-known and always considered reality.
@Shimmy Shai It's a mix of maths, experience and simulation. There are a number of RUclips videos on the topic. For example: ruclips.net/video/4VTtkF5fzMM/видео.html
I have to say this: Derek video did not convince me at all. No matter what everybody else was saying. Your video cleared everything and comprehensively. For this kind of problem it is not possible to disregard transmission lines theory or not defining the voltage threshold at which the lamp would turn on. Well done!
I was very distraught when I saw it first. After multiple viewings and seeing a lot or reactions to it, when I finally figured he was simply taking about the original capacitive transmission between the lines I felt better, but I was still not feeling great about it. EEVblog's video helped a lot. And now Mehdi's video explained it succinctly. I feel it wasn't derek's proudest moment. He made a lot of simplifications in order to make it sound shocking and counter intuitive. I think he could have done a better job with it.
yes his vid is really good..And now i will burn your brain: Actually if you are sawing wood,the energy isnt transmitted directly by the saw itselve (not as you would see it macroscopically),but also by electromagnezic waves. Why you ask? Because the saws material is made of atoms not even touching each other, but having a certain distance. So the force cant even be transmitted by them, as you might think. The force is transmitted by the electric attraction of the protons to the electrons, plus the repulsion of two protons plus the repulsion of two electrons. So also the energy is transmitted by electric fields. Also due to little inner movements theres also a very very very tiny magnetic field+electric field created (similar to that in a crystal inside a lighter, bur way weaker) which also propegates outside of the saw,and this will also bring the energy to the wood. I hope your head isnt smoking right now.
Totally agree with you. This and the suggestive way the video was presented by Derek really doesn't do the whole topic justice. It's a complicated topic and disregarding everything that has been taught as »lies« is just exaggerated. Also, Derek never actually said why it was supposed to be 1 / c and that the 1 in the numerator comes from the distance of 1 meter of the lamp and battery. It was really posed as a trick question because the actual background of 1 / c was never fully explained. In just the plain words as said by Derek, the units of 1 / c wouldn't add up, because it would be seconds per meter. Only if you bring in the 1 meter of distance, it starts to make sense again in the context of Derek's video.
I just love how Mehdi explains everything in such an intuitive and visual way. Mehdi doesn't showboat to look smart, you can tell he's smart by how he brings you up to his level.
Derek is also actually smart. I wouldn't say he "showboats to look smart" he just presents the information in an engaging way for general audiences. He doesn't need to look smart because he IS smart. Both creators can be good and smart, even when critiquing eachother. Especially when it comes to science.
@@baboonaiih The way Derek fails to explain this matter to the general audience, being undeniably more cryptic than it should be (as shown by the electroboom explanation), gives me the impression that Veritassium didn't fully understand what he was trying to teach us. It would also explain why he was making deceptive, exaggerated, even fallacious claims in his video. There is also another explanation: he didn't care enough about trying to create a good, informative video as he previously always did, but instead distorted the facts to create a click-bait, by making an extraordinary and extremely counterintuitive claim. He has somewhat done it in the past: ruclips.net/video/CM0aohBfUTc/видео.html
@@baboonaiih people who truly understand know the sheer stupidity of Vertasium and many of his videos. So they comment accordingly. People who have passing interest can be spectators, be satisfied with Vertasium stupidity, and make comments like yours. Let me give you an analogy. Suppose a RUclipsr made a video that a tire rolls down hill because the earth magnetic field pulls on the steel radials and not gravity. Would you be as kind to them, when you *know* the truth: gravity. Now imagine 6 million people going along with the RUclipsr's stupidity, do you simply say oh well, it's all opinion and just a bonner battle. If you do, go stand in line for the stupid bus. It's getting full and you want to be sure you get on it.
@@joeboxter3635 so you think harass someone who made a wrong thing but sincerely sorry for it and will fix it in the future is cool lol? If you think you haven't done anything wrong in your life then you must have done nothing lol because people only not made mistakes when they did nothing. P.S: also your analogy is shit
@@lovell8983 He has never admitted he made a mistake. In fact, he has doubled down. So don't even go there. And this is not the first such video. He is laughing all the way to the bank having made $30000 and counting on this video alone. Why does he have to do anything but take down video, if he admits he was wrong. And of course people said he was wrong around the 1 Million mark. He has made additional $25000 leaving it up, that's why. It's not harassment. It's speaking the truth. So just take the stupid bus. Let people know from "go" Vertasium is wrong say so. Just like EEblog, Electroboom, and handful of others who are calling Derk on his foolishness. The fact that you don't follow the analogy just says that you belong on the stupid bus, BTW. It's an example just like Derek's, where gullable people would fall prey for a fictional answer. And indeed there are many flat-earthers who have fallen for the magnetic explanation.
Oh my god I was going to leave a comment and then you showed the two giant loops and I HAD to. I ran this experiment last weekend with 1km of wire and a ~20ns rise time “switch” and tried a bunch of variations including the two big loops - spoiler alert - the two loops makes the effect completely vanish within my ability to measure (without changing load resistance). I’m hoping to edit that all up ASAP but I had a question - in your analysis and in the great eevblog video, you both use the classic transmission line model with inductors and capacitors, and state that the coupling between the wires is predominantly capacitive, but in this case where you are only actively applying a current in one wire, should we be worrying about inductive coupling between the wires? Like a straight-line transformer? Like the capacitive effect, it would die out as soon as the current hit steady state and the magnetic fields weren’t changing, but I haven’t yet run the numbers to know if it’s super tiny relative to the capacitive coupling. I thought your analysis was fantastic, and now that I’ve done it for real I can confirm the traces you drew were extremely realistic. I’d add that on a wire that long in the real world, “any current” is basically all the time - especially in the wind… adding to your “always on” conclusion. There was enough noise that the scope was actually super hard to trigger… Thanks!
I work at a high voltage company. A good explanation of inrush this is. We still don't have long 100km 380kV AC cables, because the initial voltage is too high when the cable is switched on what would create a fault in the insulation of the cable, or in the the installation.
Oh well done, this is by a LONG way the best presentation of this I've seen so far. I've been pulling my hair out for weeks. I've been utterly astonished at the uniformity in misunderstanding that has existed on this topic since Derek's video. Even scientists with a PhD have overlooked the basic things you pointed out with such clarity in your video. I'm so pleased there is now a video by someone who knows what they are talking about that is as comprehensive as this. There's a few other topics you could have covered, such as the Poynting vector and superconductors, how the potential energy in the vicinity of the bulb (carried there by the wires) is transformed into light and heat energy in the bulb and the Poynting vector corresponds precisely to this in the vicinity of the bulb, how radiative energy is distinguished from potential energy in the electromagnetic field, how ohmic heating works and how the Poynting vector points into the wire (at the surface) when the wire is not superconducting, how the speed of transmission is related to the dielectric constant and so on. But you covered the most important topics for understanding Derek's original video, which I consider to be quite misleading.
@@blinded6502 Those people with PhD are not wrong, but they jump right into the Poynting vectors and deep physics, ignoring the big picture. They have pre-existing knowledge about these things, they already know the good explanation, and that’s what they agree with, not what is in the video. They don’t understand how confusing it is for someone with “only” high school level knowledge, especially when that high school was a decade ago.
While watching Derek's video i thought about my transmission line class in college. I remembered very little of it but his explanation just didn't seem right. ElectroBoom brought it all back in a rush of educational bliss! My mind is now at peace.
Electroboom, I'm a retired electrical engineer. I love your video. I wanted to say, importantly, the word is impedance NOT impotence!!! Yours is the third of three videos I've watched on this. First was Veritasiums, then Dave at EEVblog, then yours. Dave said that we engineers think about things differently. That we have tools to analyze things and validly track physics and the rules of science. You fellows have collectively reminded me of much of the complexity we were trained to understand and analyze and calculate. I've much forgotten what I was trained and educated to deal with. I've been so browbeaten by the mindless politics and public chaos of people and the media news etc. I've forgotten the promises of my youth and education. RUclips, multimedia and Internet is a terrible way to waste a capable mind. You've helped to retrieve my past capabilities. Thank you. Amind is a terrible thing to waste, and you've given me a wake-up call.
7:34 blew my mind, the transmission line analogy blew my mind even more. Now I feel disqualified holding an electrical degree. When I watched Veritasium's video it made me more confused; while your video actually gave a very detailed picture of what Veritasium is trying to describe, props to you ElectroBoom :)
The transmission line analogy is only valid though if the two lines are close to each other in order for the cross capacity to exist at a reasonable value.
@@embeddor2230 No, only valid if the space between the two wires is far smaller than the length of the wires. Which it is. 2-wire lines are COUNTERINTUITIVE. Also, we're NOT allowed to ignore the inductance per unit length. That creates the magnetic part of the EM fields. For example, transmission-line calculator says that 1mm wires spaced one meter apart have a line-impedance of 911 ohms. Or bring those wires only 1cm apart, giving Zo of 360 ohms. So, going from one meter gap to 1/100 meter only changes the characteristic impedance by less than three! (Or, go from 1M to 10M spacing, and the Zo goes from 911 ohms to 1190 ohms, only a 30% increase with TEN METER SPACING. If Veritasium used an LED, then it would immediately light, even if the space between wires was 10M rather than 1M.)
@@embeddor2230 > The transmission line analogy is only valid though if the two lines are close to each other So you appear to be saying this? ...if two long wires are one meter apart, they don't form a capacitor anymore. The gap is too large! Also this: if a big wire loop is made 1M in diameter, it stops being an inductor. The wires are too far apart from each other! If that's not what you're saying, then your claim appears to be an unsupported newbie misconception. As wire-gap increases, and if the wire diameter remains the same, the Zo line impedance doesn't increase as inverse-square or inverse-cube! These lines are closely coupled (very long, where the 1M gap is almost insignificant. That's why we can apply transmission-line physics.) Transmission lines are COUNTERINTUITIVE, and if we aren't RF engineers with some EM fields/waves classwork under our belts, we're going to be trapped in newbie physics-misconceptions. For example, how does the Zo line impedance increase, as we separate the wires? Start at 1cm, using Dereck's cables (which appear to be roughly 5mm diameter.) Gap size M | Zo in ohms 0.01 - - - - - - 158 0.02 - - - - - - 247 0.05 - - - - - - 359 0.1 - - - - - - 442 0.2 - - - - - - 525 0.5 - - - - - - 635 1.0 - - - - - - 718 That's from the online calculator at Clemson TL_calculator... cecas.clemson.edu/cvel/emc/calculators/TL_Calculator/index.html To bad Veritasium didn't have his wires be 10M apart! With 5mm cables, the Zo is only 1K. Then use a 220VDC battery, and light up a bulb, where the billion-foot lines are only putting 2K ohms in series with the light bulb. .
veritasium is a fool as he not taking impedance values into the equation..light takes a second to reach the moon.current flow will be slower due to the resistance of the wire at power up.
If I had a professor like you in college, I would have been an electrical engineer and not a mechanical engineer. It's so facinating and amazing and you do such a great job of explaining it!
Being an electronics engineer myself, seeing Veritasium's video left me with some thoughts of "hmmm, I don't know if that's that..." Thank you for showing things were in fact the way I thought they were.
Another RF engineer here. Some thoughts that I want to shared wit you: The large peak Electroboom saw in his LTSpice simulation at t=0 is due to the capacitance of the TX line (as he mentioned), which is a short-circuit for the high-frequency content of the voltage step created when closing the switch. I think that in reality high frequencies are radiated from the battery wires to the lamp wires (a.k.a. a spark TX ) and a small amount of energy is picked by the lamp. That energy arrives 1/c seconds after switch is closed. It is just not enough to turn on the lamp, but I think that pulse (or transient) is what Veritasium was addressing as "lamp on"
I took a rf course and I'm glad it lays out a very important foundation for me to understand pcb level transmission line stuff and of course questions like this.
@@Ducktility Your comment is how to tell someone is still in school and isn't yet a physicist with an engineering job. Seriously though most physicists I know still consider RF black magic. It is one thing to know the fundamentals on a base physical level, its another to make it happen.
@@Noubers You don't really understand fundamental research, do you? I'll give you a small example: Theoretical physics: Hypothesize electrons Applied physics: Discover and demonstrate electroluminescence Engineering: Improve LED efficiency and make it useful to the world.
The thing I learned in uni is that "energy" is literally anything that _can_ do something. A ball on top of a desk has energy, potential gravitational energy. So yes, the EM field carries energy. But a moving electron creates EM fields that carries energy. So, in a way, electrons (moving ones) are carrying energy. It's a useful abstraction! Derek's video also rubbed me the wrong way, especially how the light turns on at _any_ energy level. I figured that in that case, the distance from the switch to the light bulb would be significant, since it should carry _some_ energy, or something like that. I think the general premise of his video is good, but the dissmissal of abstractions and trick question did a disservice to it, in my opinion. Loved this one tho!
His video also bothered me because his answer would be the same (1/c) if you had an open circuit at both ends of lines. It all boils down him being technically correct but pretty wrong in practice. It also doesn't help that he's basically clickbaiting and fooling a large audience into thinking they were taught wrong their whole lives.
One of my best physics teachers in uni used to tell us that energy is just a "conversion currency" between different phenomena, once again, a useful abstraction.
I don't know if I'm being naive here. But I think the point of Derek's video was to show that energy is carried by fields, The trick question and the exaggeration are means of engagement. And I think this because of his videos on clickbait and viral videos. what is good: it creates a chain of videos that respond to his, and leads his viewers to these videos. Since the alghorith tends to couple videos of simmilar topics and audiencies what is bad: He could have achieved the notion he wanted. That energy doensn't goes through wires (wich we done well), and after that, actually ground his clains, remove te hyperboles, and explain that distance hardly relates with power. The problem with his aproach in my opinion is (if this was his aproach): his original claim, that we were taught to us is wrong, what he ultimatelly did, is also wrong, but in the reverse direction. The naive defence that I kinda have is that his intent is to create more videos about, and simultaneously raise awareness to the subject and other creators, but how could someone judge the sucess of this (if is really his intent) and wouldn't it fu** his credibility if after the video you don't know if he was tolding the truth or running some kind of community awareness experiment?
@@dan1RR I make your words mine, couldn't have put it any better. One thing I'd like to add is about the "you were taught wrong" approach. While it is true to some extent to say that and brings in views, I'm much more fond of kurzgesagt's approach. Which is to say "you were taught wrong, err, sort of". The "lies" we're taught are just simplifications and abstractions of a messy reality, so that we can slowly build up our notion of the universe. Derek just says "you were taught wrong" and doesn't elaborate any further. It's almost paradoxical, he is diving deeper into a subject while also staying at a shallow level. Which is why I believe it was a disservice to himself. I hope my point makes sense ;w;
He talked about demonstrating this with an experiment, so I wonder if he was being intentionally vague in order to make a follow-up that explains things more thoroughly.
@@Harambe8 A month ago he did a question in a community post and a video about a string hanging from a helicopter. It was an inadequately defined question. I remember there were some about cosmology or particle physics that didn't sit well from years ago. Its not always the basis of the whole video, but it does seem about every other video (that I watch) he will say something questionable.
I watched Veritasium's video when it came out, and knew I had only to wait for your excellent response. Is this (friendly) rivalry going to end with you both teaming up to create a real ~300,000km long circuit?
@@ElectroBOOM As electrical engineering student, I really hated how people fanatically believed that his explanation is 100% right and who disagrees is just stupid.
Kurz did a very good video on the "lies" of science communication's required simplifications of complex topics. But the way Veratasium said that we were taught "lies". Annoyed me a lot especially when he hyper simplified his example down and ignored so many potential losses or other important variables in his explanation. Which as you have shown in this video is a "lie", ie simplifcation of a topic. He took issue with a "lie" then explained why he thought it was a "lie" by "lying" about it? Why is it not as clear if not clearer to explain that its a nessecary simplification for base level understanding of electricity? Rather than to give the impression that people are being taught falsehoods. Potentially damaging peoples trust in the education they have been given on other topics.
Well, he did the exact opposite to what Kurz is trying to do - he took a pretty simple and quite valid model and complicated it with what he presented as "fields and vectors magic"
This is especially gross considering the massive amount of science denialism going on today with climate change and covid. These people know better than to label these models lies.
What made me laugh most is I instantly picked up on the fallacy of Derek's idea that the chain in the pipe was a poor analogy when I saw his video. I tried to imagine an engine that would work with such movement, but got bored trying to figure something out. The simplicity of a saw cutting through wood was like a smack across the face.
Thank you for setting the record straight. Derek's was indeed a trick question based on language. "Turned on" is a concept that we associate to the circuit being at operating current. He should have said "receiving any energy from the battery". Which also the rocks did, by the way.
Exactly even worse he drew up the problem to SEEM like it's asking about DC steady state but OOPS it's a transmission line problem! If it was really asking about the transient state any person correctly modeling the problem would draw the appropriate distributed model of the transmission line. Unfortunately oops he forgot to draw the LC network! That would be a great way to get fired for incompetence in the real world but like you said he did this all intentionally for attention.
Yes this was not very impressive by Derek. Either he doesn't actually understand what happens, or he deliberately fools the audience. In any case, most people will not be any wiser from his video.
He seems to like to do a lot of this type of trick with his video titles or main questions raised in the videos themselves. He seems to enjoy being like "See? Nearly everyone is wrong about this thing!" due to some trick of phrasing/language.
I love the pun in science where a mathematical vector points in the direction of energy flow was pointed out by the scientist John Poynting and for which we credit him and call it the Poynting vector.
As someone who took one course of electrical engineering in college, I also thought the Veritasium video felt like a trick question and left me kinda confused. This video made it clear what was actually happening.
I love it when someone makes a video/hypothesis about science and people, scientist, engineers from all over the world try to replicate the idea to try to prove/disprove this idea. It's the same concept used in academia but making it accessble to the world. +1 to youtube.
I am an electronic engineer and Dereks video made me question my education. I think of that as a good outcome. And I immediately wrote he was wrong. I am so glad Boom made this.
same happened to me, but i am salf taught on electricity and electronics...i got so lost on his video that i wrote comments to disagree with it...for me the light only turns on when enough current flows to make it glow, he never referred to the wires as big antennas or a capacitor and he never mentioned leakage current, he also never mentioned background fields and he never mentioned how irrelevant all of that is on a frickin DC 12 lightbulb circuit, if he explicitly mentioned that, then i would understand the subject instead of wasting all my brain cells to find ways to disagree with him
Excellent explanation. And the opposite will happen when you switch it off: the lamp will not go out instantly, because of the stored energy in the capacitance and inductance. Brilliant. I even dare to say that a similar effect will happen with mains AC when it gets switched off: ringing needs to die out, or there's momentum in the rotating 3-phase power grid. At home when turning off the light, it gets dark instantly. When a power outage happens because of a grid failure many miles away, the light will fade out in a fraction of a second, instead of going dark instantly. Seen it with my own eyes.
The biggest thing you've demonstrated here is that the field strengths are strongest when closest to the wires. That alone clears up the main issue with Veritasium's video I think!
I think the main issue with his video is that he said that electrons moving through a conductor is not how energy is carried in a circuit. It takes energy to get the electrons moving and without those moving electrons no energy is transmitted. Sure, they do so in the form of EM fields, but it's the moving charges that generate those fields. It's like saying a hydro dam doesn't get its energy through the movement of water, but instead through the influence of gravitational fields.
Yes, Veritasium confused 2 different things: - Electricity is propagated around the wire, but still close to it, following it. - If you attach a battery and a switch to a piece of wire, and start switching it (like a Morse code), you created a radio transmitter. One is good for transferring electric energy, other is good for transferring information.
Agreed. Derek implies that most of the energy is flowing through space, which it's not. Those fields are going to be concentrated almost entirely along the wires. It was also really wrong for Derek to say that "it's not what's happening in the wires that matters". If that was the case, then why would you need wires at all?
Yes, Derek's argument was all qualitative while leaving out ANY quatitative qualifications which usually leads to severe misunderstandings and wrong conclusions. Sometimes you really have to do-the-math to understand what's really going on.
The fact that millions of people are willingly watching these kinda videos shows that we can teach it in an interesting way and school isn't the end of the story
i still cannot wrap my mind around how exactly is that possible. Can someone explain in different words whats happening there? Or explain it like im 5 or something
Poynting theorem states that closed surface integral of E×H = rate of decrese of energy stored by electric field and magnetic field in the volume of closed surface minus the ohmic losses Ohmic losses depends on the conductivity so simply I can say that power flowing out if any closed surface integral of E×H Now in above case (DC)since magnetic field set up by DC current is constant so as the electric field. So there is no there is no propagation of E and H outside the wire... It is just a set up of E and H. The stored energy due to electric and magnetic field outside the wire is not changing with time Sooooo..... Poynting theorem only depends upon conductivity. Since the conductivity of the medium outside the wire is zero ,,so it will not propagate outside the wire.... Derek is only looking at E × H in this video actually E× H is not propagating in case of DC According to him he can transmit energy wirelessly at 0 hz. Moreover he is right that current flow and energy flow are not in the same direction..... In case of AC you can transmit t using the above concept but then again you need some waveguide for the energy flow.
Basically, there is a parasitic capacitance between the separate loops. So, the higher the frequency, the lower the parasitic impedance and the signal passes through the air (dielectric) and reaches the other wires.
I watched Veritasium's video first, and, while confused, I learned the interesting idea of energy flowing around the wire. After watching yours (despite getting a bit lost in the second half) I understand better how it actually works
@@bremset I think that’s the commonly agreed understanding of that phrase. When the adjective describes getting closer to 0 of some value, the multiplication uses the inverse value. Becoming weaker is trending in the direction of 0 strength, so 100 times weaker means 100 times closer to 0 strength, or a multiplication by 1/100. This is language dependent, because you have to already agree that weakness isn’t quantifiable alone, but only by reference to some amount of strength. 0 weakness doesn’t fit into reality as well as 0 strength does. Just like how infinite strength is unrealistic but infinite weakness is realistic. You can argue against these assumptions scientifically, but to understand the phrase “100 times weaker” as it is commonly used, you have to start by agreeing with them.
11:15 and 12:40 is exactly how telecoms people (like me in a past life) see current flow in a pair of wires. Along the way, you beautifully explained the concept of Characteristic Impedance.
I believe that ElectroBOOM is trying to explain the practicality of the theory rather than the theory itself, which is amazing. While Derek is trying to explain us the theoretical part of this idea. So, I recommend that both the videos are correct but its just 2 ways of looking at the same problem, and can get different answers because the conditions in the way we look at the problem has changed. it's like looking at a sheep(the problem) being colorblind and another looking at a sheep wearing colorblind glasses although he/she can see very well without the glasses.(Not being biased or sarcastic!) But both the videos express great ideas to think of and learn,, THANKS both of you... And I am subscribed!!😃
For future reference it might be interesting to point out that LTspice has a dedicated component model for ideal transmission lines "tline" where the only parameters are line impedance and transmission delay - you can use that to simulate the 1s delay (or any other delay for that matter). And of course for more accuracy there is a lossy transmission line model "ltline" - which is described by the lines inductance, capacitance and resistance per unit of length and the line length. Either could be used to simulate this exercise.
Really love and appreciate the editing here, especially with the white board scene! Made things really fluid and in-pace while also being digestible and easier to understand. Thank you Mehdi!
Thank you for making this video. Derric's video didn't sit well with me, and luckily there were many in his comments' section that pointed out this very issue, but it's nice to have your detailed explanation to really iron out the caveats.
Sometimes it might seem like person knows what he's talking but they're bullshitting you. Not in this case, Mehdi is actually right but others might be wrong. Like Veritasium who seems like he knows what he's talking about but he's been straight up wrong few times
@@realdragon I heartily agree, but of course there is a difference between talking out of your ass and making an honest mistake. Considering Veritasium's sportsmanlike acknowledgement that his brevity sacrificed precision, he doesn't seem like a bullshitter to me - though I am not familiar with his content beyond this reply
@@cryhavocandletslipthedogso1873 He might not be bullshitting on purpose but he has wide audience and that audience who doesn't know any better believes him. He also made video of why water running water bends when you put electrically charged object near it and he wasn't just mistaken, everything he said was straight up wrong and it's easy to prove too
Veritasium made it explicitly clear in earlier videos that they optimise their content for the RUclips algorithm and to maximise viewer numbers, and prioritises this above the desire to provide content that educates. The Veritasium video was carefully calculated to be click-bait and cause maximum outrage and confusion in order to boost viewer numbers. By this metric, Derek's video was a highly successful money maker. This profit was however achieved at the expense of annoying everyone who already understands transmission-line theory, and insulting engineering teachers by calling them liars.
I remind you all that it was his thesis that tricking people into the wrong answer would lead to better learning. So he went asking people on the streets and shows the wrong answers on the video, to then show the explanation. Baiting and triggering question always were in him.
Best response to this so far. It's been occupying my mind for a week or more, too. Those simulations answered a lot of the outstanding questions I was still wrestling with. This video also addressed some of the things I disliked about how Derek presented it. For example, Derek's presentation of the material seems to imply that the wires are immaterial, which raises the question of why do we even need wires at all. The answer is exactly as you presented. The wires are devices for constraining the path of the magnetic field and by extension, the energy flow to where we need it. Great job!
Does 'the wires are devices for constraining the path of the magnetic field and by extension, the energy flow to where we need it' mean that the energy flows outside very near the surface of the wire rather than inside it?
Poynting theorem states that closed surface integral of E×H = rate of decrese of energy stored by electric field and magnetic field in the volume of closed surface minus the ohmic losses Ohmic losses depends on the conductivity so simply I can say that power flowing out if any closed surface integral of E×H Now in above case (DC)since magnetic field set up by DC current is constant so as the electric field. So there is no there is no propagation of E and H outside the wire... It is just a set up of E and H. The stored energy due to electric and magnetic field outside the wire is not changing with time Sooooo..... Poynting theorem only depends upon conductivity. Since the conductivity of the medium outside the wire is zero ,,so it will not propagate outside the wire.... Derek is only looking at E × H in this video actually E× H is not propagating in case of DC According to him he can transmit energy wirelessly at 0 hz. Moreover he is right that current flow and energy flow are not in the same direction..... In case of AC you can transmit t using the above concept but then again you need some waveguide for the energy flow.
@@jakkank That's what Mehdi's talking about between about 6:30 and 7:10 in this video. The magnitude of the Poynting vector is proportional to the product of the electric and magnetic fields. The Poynting vector shows not only the direction of the energy flow, but the magnitude of the energy at that point in space. For a DC circuit at steady state, the magnetic field is strongest just outside the surface of the wire and drops off in proportion to the inverse square of the distance from the wire, so the energy flow will fall off fairly rapidly as we get further away from the wire. Even for the relatively low line frequencies we use for power transmission (ie. 50-60Hz), this will still be generally true. We will leak a little more energy into the wider environment, but most of the energy will be flowing close to the wires, most of the time. There are caveats to that statement, which is why things like radios and microwaves work but that's also why we don't make our transmission grid like a radio and operate it at a relatively low frequency. That way, most of the energy flows close to the wires to the load where we need it.
I love how some of the best tech RUclipsrs are getting into debates, ultimately educating us in a more in depth fashion than if it were otherwise. As long as it stays into the domain of constructive criticism, these videos will be some of the best content around. Thanks @electroboom and @veritasium!
Derek is not a best tech RUclips, not even a little. If you watch his videos he wanna look like a star talking to people to show them how stupid they are, and trying to learn from professors. Its a personal diary about himself, how he risks his life, how he wins a debate etc
The downside of the youtube debate format is that smaller channels have less (sometimes no) visibility, so even when they are correct, the lay public never sees their corrections, and only see videos from large channels, even when the content in them is misleading or just plain wrong. Not all viewers will dig through the myriad response videos to find the answer, and even those that do may not have the scientific or technical background to understand the arguments being made.
@@Vasharan Absolutely correct. That's why rich people who run moneymaking accounts like Derek's have a very big responsibility, and their negligence is rightly criticized very harshly. Clickbait BS shouldn't be rewarded.
This is actually quite a common phenomenon. Many popular wide-topic blogs (sci-pop included) seem at first really comprehensive, until they hit one's specific field of knowledge, at which point one realizes they are superficial, inacurate and often misleading concerning even essential details.
Thanks for clearing that up. I'm a retired Professor of Physics and Electrical Engineering and struggled a little with Veritasium's explanation. You filled in the gaps and turned on the switch to my full understanding.
The more accurate transmission line simulator is currently what I'm researching for my master's! I'm very happy about this video as Derek's video did make me feel uncomfortable with regards to how small the amount of power the light bulb would receive, which you address in this video. Derek's video does well to highlight the idea that electricity is in fact a travelling electromagnetic wave. I think both videos work well together! So happy to have all this relevant content
10:35 makes what Derek's video was trying to explain so much more clear to me. After I finished his video I was still kinda scratching my head. Seeing it this way makes the Poynting vector explanation seem more like a red herring for the _reason_ and instead just a mathematical representation.
That is because when one truly and deeply understand a subject, they can explain it to anyone. I think Derek's intentions were not only to teach something to their viewers, but also to get more views, sadly.
The NYU Quantum Lab has a good discussion on this - while the math works out, as Feynman argues it's rather questionable to interpret the Poynting vector as showing energy flow.
I saw the trick question AND the errors in his explanations all throughout his video... but I work with long transmission lines, electro-magnetic coupling and currents all the time through my occupation. Derek's video struck me as being both partially correct and yet partially wrong at many levels. Thankfully, your video elaborated on most (if not all) of the errors.
Yeah, I worked on them in collage 8 years ago, and had the exact same reaction: Which was, that's one way to think about it, but it's not the only way, and both are correct in their own ways.
@@Supernov4 because we can apparently learn whether the far end of the circuit is open or closed faster than it would take light to reach us from that distance
As an electrical engineer myself, I knew SOMETHING was wrong with Derek's video; I just couldn't pin point exactly what. Thank you for making this very detailed explanation!
@@joefuentes2977 Dude, he called himself Electrical Engineer. His literal job is to design power transmission lines, transformers etc. He must know this stuff - I don't believe a single college will let you graduate with EE diploma without knowing this. Hell this is high school stuff, he just worded it super weird and used a trick to con people into assuming a false answer, as explained by Mehdi. Anyway, a real EE engineer should be able to see through it.
Thank you so much for this video! I watched Veritasium's video and was left feeling that everything I had learned about electricity was wrong and I was never going to understand how it really worked. After watching your video I have come to the conclusion that electricity is more complicated than I first thought but I should probably go back to thinking of it practically as electrons flowing through a continuous circuit as this has at least so far stopped me getting electrocuted and you are a special kind of genius to be able to not only understand all of this but also explain it in a way that is so entertaining and doesn't make me feel like an idiot.
There is practical and there is theoretical electrics. Practical is more than fine because a massive amount of assumptions can keep you safe. That being said, you don't violate the rules in those cases. Theoretical electrics tells you that static is not random and everything is calculated and nothing is too small.
Oh my GOD, this is brilliant! He literally answered ALL the questions I had crop up during the video! This is actually WAY better than veritasium's video
Dude, such amazing editing in this video! The sound effect as the field began to propagate, the "Don't watch if you have diarrhea" in the disclaimer, the elevator music from Mass Effect... just amazing!
Yeah the whole trick was to conflate 'immediately' (time), with sensitivity (power level). I think instinctively most people would have realised a switch being closed can affect a neaby device without being physically connected, but can't usually provide a large quantity of power without a decent cable connection.
This actually reminds me of the days when I was twisting my head around RF circuits :D All of this is known and I really appreciate you pointing out the workable models to think about this.
Wow, I feel like I'm watching an old-school Electroboom video with no mercy given for viewers who still need to do their homework. Fantastic. I did sorta expect a homebuilt circuit, though, that used components to simulate Derick's thought circuit. Not to measure 1/c action, but just because.
Derek's explanation dismisses the principle of locality by suggesting that the fields alone transmit energy. The fields need free electrons with which to interact and they have to be fairly dense to transmit measurable amounts of energy. The chain analogy is apt because each link in the chain pulls only against its nearest neighbor.
I think that in transmission there is locality that can connect through air as well as wire and it is all one thing... but where he's wrong is thinking that the Poynting vector equation describes an evolving circuit. It describes what a circuit evolves INTO assuming that there is an equilibrium to find. He's using an equation in a completely wrong context.
That's the principle I was looking for! My biggest problem with Derek's explanation was that while the source and load are only 1 meter apart, you can't have the energy flowing all the way _around_ (half) the loop in 1 m / C seconds without information traveling faster than light. (Though I don't think that was what Derek was saying at all.) Imagine the switch being half-way along one side of the loop. Assume you're observing at the load, but somehow know when the switch is thrown (perfect synchronized clocks, perfect actors, and a pre-agreed time to the nanosecond -- or just go with "magic"). The switch is 1/4 light-second from the source and the load. Thus, it takes ~1/4 second for the information about the closed switch to propagate back to them, inducing the current locally and turning on the light. It doesn't matter whether you model the electrons or the fields as carrying the energy here, the result is the same: the light cannot turn on in less than 1/4 second. Otherwise, we could transmit information faster than light as long we had a long enough wire. Frankly, because of this, I'm struggling a bit to mentally model how the light comes on in 1 m / C seconds here at all, but it kind of made sense to me intuitively until I started thinking about it like this. I'm using the assumption that having the switch anywhere is equivalent, but I think that may be wrong due to the extreme nature of the circuit (i.e. this is theoretical physics, not engineering). That seems most likely. So maybe in my scenario, it takes 1/4 second, but my scenario is not equivalent to Derek's. That would work fine with Derek's scenario, because the pre-switch state information has already traveled around the wire, and the switch is local, so the _local_ electrons at the source can move/interact as soon as the switch is thrown. However, that would still throw some doubt on Derek's claim that the field carries _all_ the energy, only proving that it carries at least _some_ energy. And if it carries some energy, it could only have gotten it from the source, thus it carries at least some of the circuit's total transferred energy. That still doesn't mean Derek's claim is wrong, just that it's not entirely proven by his example model.
@@bloodgain I should clarify that the fields do carry all of the energy (as photons), but only from one electron to another. In a conductive wire, free electrons are abundant so the electric field carries energy very short distances (as short as the distance between two atoms). But in the insulator or the air gap between wires, free electrons are scarce so the magnetic field is able to stretch out and transmit energy at great distances. Energy takes both paths from source to sink, but the magnetic field can only carry pulses of energy whereas the electric field can carry a steady current (up to the limit imposed by the resistivity of the wire material; Derek's 1 light-second long loop of wire is far too long to carry DC the full length even with the highest conducting materials we know of).
Thanks for this, Mehdi. I kept showering thinking about this all week and every day I was like, "The electrons have to move to create the fields." I'm glad I'm not a total failure of a physics grad.
This really fixes the misleading aspect of Veritasium's video. I left that video knowing there was something wrong with how he presented the notion that the power only crosses the three meters. Now it all makes perfect sense.
The biggest problem is probably the clickbait title he put in his video. It's going to cause major misinformation for anyone who doesn't watch these follow up videos.
I had seen Derek's explanation and thought "wow..this is amazing, i learned a secret of the cosmos". Then a LOT of other video's started to appear from people that where smart and learned, and i watched those as well. I LOVE it. This is science as it should be. Respectful, and always, always let the evidence speak..not the emotion. love you guys..do not understand everything..i am a simpler man..but i love how you all work with science.
I think it's great that youtube "drama" and "feuds" are being used by the YT science community to get people interested in deep dives into science that they may have never been interested in.
SIGN ME UP for scientific debate on youtube. I legitimately think the chain string series should be taught in schools, not for the specific topic, but more for the honest scientific debate and scientific process they used to come to their conclusion.
Mehdi, as an electrical engineer I wholeheartedly thank you, you are pretty much the only goddamn person on the internet who seems to ACTUALLY know about what he's talking about when talking about electricity. I really don't understand why other extremely reputable channels couldn't take this same approach, and I mostly don't understand why electrical-related matters have to ALWAYS be -at least to some extents- mystified and spectacularized as if they were some sort of great big mystery. Electricity is """fairly""" simple, and it would be much much much more simple if people stopped picturing it at some sort of goddamn magical force. Never stop educating the masses Mehdi, NEVER STOP! You really are the only one in the field.
@@jemert96 I do not agree. Although you (as experts) may not agree with the information, it taught me about poynting vector, which was interesting. Then it got me watching this electroboom video, learning even more on the subject! Although Veritasium should have had a disclaimer at the end saying other effects apply. But really, I'm a chemistry teacher (also physics sometimes) and any lesson I teach is incorrect. There is always another effect that makes the story nog very correct. When I started teaching I was always nuanced. With experience I found that simple is better. If the vids were correct I wouldn't have watched it, so simple is king here.
I’ve watched several videos concerning this particular “topic”. I’m a novice when it comes to electronics and much of the information is over my head at this point. HOWEVER, it has certainly sparked my curiosity and I feel compelled to LEARN MORE and educated myself. Thanks to ALL of the “RUclipsrs” for helping us to learn more.
This video is great and well done! I am not a fan of ElectroBoom. But I am a fan of the young Derek M. What I love about THIS video is how nicely you express the ambivalence of your feelings/understanding. The topic can be seen and described in various ways and you totally acknowledge that. Wonderful. I realized from this video: Maybe the better question would be: when does the earth formation that the switch is closed reach the light bulb.
Thank you so much for making this. My dad and I were going over Verisatium's video with very similar reactions, and I realized that he's just made a really inefficient capacitor, because for the light bulb to be fullbright immediately, means that causality was broken. I missed the black box amplifier bit, and you made a great point about that too.
It isn't just a capacitor, it's a *distributed* capacitor (and also a distributed inductor). In fact, neither of those alone can give correct answers, and not even a series of lumped components like in Mr Boom's simulation can get it quite right. Transmission lines should really be thought of as their own kind of "thing", somewhat like but also somewhat unlike both capacitors and inductors.
It is an abstract concept anyway, and the answer depends on how we define “carrying energy”. In reality it is a continuous interaction wave between electrons, propagated by the fields between them. So saying that electrons carry the energy is perfectly fine, if we are describing it at a higher level of abstraction.
It _is_ the current. Consider a cosmic "ray" that's actually a particle. You get hit by those all the time, and the energy of the particle is ridiculously high. But you don't die. Now take a hammer and swing it at your head with an absurdly lower amount of energy per particle, and you may very well die. Same principle as a high voltage and low current due to supply, rather than resistance. It's trivial to zap yourself harmlessly with over a million volts, with a big enough Van de Graaff generator. It's also trivial to kill yourself with just 120 volts from a wall outlet.
I watched Derek's video the day it was published and had to admit I was lost halfway through. This video finally made me understand what Derek was trying to say, and why you think it's inaccurate. And had to admit your argument made more sense. If we assume there is no resistance, then we must also assume there is no capacitance and inductance, which in turn means there's no electrical and magnetic field. The question then becomes pointless. The resistance in this case cannot be negligible.
No, that's not what he's saying. You can assume no resistance, and in fact Medhi is assuming no resistance anywhere in the wires. Despite the wires not having resistance though, they act as if they do, due to the way that the inductance and capacitance couple together on a long pair of parallel wires. Superconductors exist, but even if you made this circuit with superconductors, the circuit would act as though it had a resistance equal to the characteristic impedance of the line, up until the EM fields have propagated to the short at the far end. Even with completely superconducting lines, the light will see very little power until the field has had several cycles of propagation around the loop, unless you have the absolute best case scenario where the resistance of the lightbulb is equal to the characteristic impedance and thus you get half power (edit: actually half voltage, not half power) immediately (and you still don't get full power until the propagation delay is complete).
@@clapanse In his video he says "how long will it take for the bulb to light up", not "how long will it take for the bulb to receive full power". The bulb will light up with half power, just not as bright.
@@rdizzy1 it'll likely light up at a tiny fraction of half power. Half is the best possible scenario if the impedance is matched perfectly (actually half voltage, which will give 1/4 power on a resistive load like an incandescent, or likely not much power on a nonlinear load like an LED), but if you figure out the characteristic impedance of the proposed setup and typical lightbulb impedances, the realistic answer is far, far less than half (and likely several reflection cycles before a decent amount of power is transmitted).
Thank you for making this video! While in hindsight I can clearly see that I should have gone into more detail with the explanation, I have really enjoyed watching all the response videos. For the record I was not suggesting the lightbulb lights at ANY current value but at some small but significant current value. I tested my LED bulb rated for 12V and found it turns on dimly when I apply 2V. There may yet be a follow up video coming. So thank you for this commentary - I'll incorporate it into any further work I do on this topic.
There he is
Alright I guess I'll look forward to the follow up video.
It's so nice to see civil and intellectual discussions between my favourite youtubers!!
isn't any current that turns the bulb on "significant"? ;)
also i doubt that'll change the fact your wires aren't magic warp machines. as soon as your current is significant enough as to not have the lamp on all the time due to background noise, your EM coupling between the "half-loops" won't suffice, while the transmission along the loops will take its time.
You guys all do great work! Thanks Veritasium, ElectroBOOM, and EEVblog. I enjoy all y'alls videos.
Thanks for the shout-out, Mehdi! This was a thorough and nuanced response to Derek's video. It's important to remember that, while the energy _is_ transferred by the fields, the current is still in control. The lightbulb isn't going to do _anything_ if there isn't a current through it. During a recent live Q&A (for supporters only), I talked about Derek's question a little. My guess was that a real-life bulb wouldn't immediately turn on, but would slowly/gradually brighten over a few seconds. It sounds like you agree, which is validating.
Hey.... I love your videos.
Cool
The funny thing is that with 10m of distance, you already have a super small current from the capacitance alone. The only correct answer, the lamp is already on, so its 0s , not matter if you close the switch or not. Oh the leak current, about about the leak current...
That was my conclusion while I watched the video, baffled.
Doesn't electric fields technically go to infinity ? even thou they decrease with the square of the distance ?
All lamps are always on by veritassium definition.
Another thing that irritates is that it was never defined what is a "turned on lamp", one would presume it would emit enough lumens, but how much ? What are you ideas on this ?
Hay a wild crazy is here
Thought to mention, even the 1 second round trip delay is not fully accurate as the LC circuit imposes its own propagation delay on top of light speed. Like I said the current flattens out traveling through the network and that slows down voltage step transitions, as you also see in the simulations at the end of video. Sorry, too much technical details!!
hello boom man
Is there any way to actually measure how much current would actually transmit over 1/c s to the bulb. Im just curious.
Electroboom come to goa and plz gave me multimeter plz
Have you seen this video? ruclips.net/video/Lp_b8gQpxW8/видео.html
This kind of debates are far better than the boring online classes. Thanks Mehdi. ⚡💯
I've begun my journey into electrical engineering as a hobby thanks to creators like you. I began watching because you were purely entertaining, and now I'm accumulating tools and measuring current and actually sat down and measured hundreds of resistors the other day and was actually excited as I thought about how it all works. I'm slowly beginning to understand more and more about how electrons move and how various components can manipulate them into doing all kinds of cool stuff. This video helped me better understand that movement. Thanks for making such great videos!
You should study electrical engineering, too much fun.
@@Sir_Charles007 hmmm I've heard the opposite lol
Uhhh... as a *_hobby_* ?? 😢
read the Thomas Floyd book
I find that really cool kind of like me but but with me it was more of going to the ocean and being intrigued by the water I've been to the ocean many times but this time it did something to me and since I went 2 weeks ago I've been doing nothing but researching oceans and bodies of water all throughout California I even love going on Google maps and just looking at bodies of water and trying to get a street view being in the ocean and the lakes and rivers terrifies me but I'm also very fascinated with it. I wish that I could find a way to go into like what you are doing if there was a way to accumulate tools or somehow get into marine biology but I hear it's such a hard field to get a job in. Idk LOL just yappin
Since youtube removed dislike count, the like/dislike ratio so far is 98.8% if anyone cares
Let's use this ^^ comment's like button as the dislike button.
I care. And keep us updated about it.
Can add 'Return RUclips Dislike' extension to chrome for now. There needs to be a petition.
@@85NP85 , assuming that RUclips actually gives a shit(which they clearly don't).
Not all heroes wear capes!
I am truly amazed that how RUclips science community holds arguments.
Like a true gentleman, Mehdi.
If I had a coin for every time Mehdi argued with a science RUclipsr...
yeah it's really nice
The science part of RUclips is one of it's best parts. Most of RUclips is is either cancer or garbage.
@@sasdagreat8052 You'd have atleast three
@@sasdagreat8052 If I had ten thousand Canadian coins for every time...
Finally an engineer that combines both the engineering and physic models without outright dismissing one or the other.
A very insightful video that perfectly complements Derek’s video and add some much needed realism to it.
If I could subscribe twice I would!
Use another acc
@Idiosarchy I think the video is still complementary because it's a thought experiment designed to emphasize a specific mechanism of electricity at the exclusion of all others. Maybe he could have been more thorough with his hypothetical situation, but I don't think it's fair to say it's wrong or misleading. If it was meant to be purely realistic he wouldn't have said the wires have zero resistance or that the lightbulb would turn on at any amount of current. I guess he did sensationalize it with his choice of words, but it's RUclips, of course he did. Is this channel any different in that regard?
@Idiosarchy The basic concept is not wrong. It really will take only 1/c seconds for a change in current to start happening through the light bulb.
Derek's thought experiment has some flaws (he could have been more detailed and specific). Just like Medhi's thought experiment has some flaws (which he points out).
No thought experiment is perfect, but it doesn't need to be in order to communicate the basic concept.
The basic concept is 100% correct.
You do realize that Physics has branches and that those branches also have branches? Physics is like the tree with, for example, the branch Circuit Analysis. You can also split your Classical Mechanics into Statics and Dynamics. You can split your Fluid Mechanics into say Fluid Dynamics. Don’t even get me started with Metaphysics. Good times, haha 😂.
@Idiosarchy the argument obviously has flaws, I never denied that. My point is that he hilights a physical phenomenon that we can understand even if the thought experiment is imperfect. At this point we are just splitting hairs even though I think we both understand the point and intent of the message. I'd like to point out that Schrodinger's cat also probably would not actually work in real life but emphasizes the strangeness of quantum mechanics in a way that is digestible to the lay person. The point is to isolate variables, not to turn sci-fi into reality
This is a perfect example of the value and importance of readily accessible rebuttals to all content online. Rebuttals add value to the discussion and people are better off when they get critical responses from other people who add nuance and further context to issues.
We need 'The Socratic Web'...
Comprehensive and briliant. Derek deserved this :-P
I love that you, electroboom, bigclive and other electrical channels have something to say about this. It's very interesting and I don't actually believe everything he said although I know I'm far naive. I loved electricity ever since I existed but I still have no complete understanding of it.
Still, thank you electrical community!
Kind of funny he predicted that it he would be called out but turned out he was called out because of the simple answer itself.
I'm just waiting for Derek's reaction to this. He seem to be very sensational in his videos and inaccurate.
sadly we will never know anymore which video is actually right since youtube removed dislikes lol
SCHOOL! The answer is I don't go! Why go? I am famous. I am famous. I have more fans than fingers multiplied with toes multiplied with teeth multiplied with ears. I am famous. I am famous. SCHOOL? No, thanks. RUclips FAME? Yes. Good day, dear eev
Hi, can any of you please explain this in terms of high school physics? What we have learnt is that current travels through two methods - conduction and induction. What I understood from Derek's video was that he was claiming that the bulb would turn on simply by induction field from the battery. The conduction field as I understand travels through the entire length of wire before hitting the bulb. And the induction field would be too weak to turn on the bulb. Kindly elaborate on this.
Also, I saw a video where the person said that if he places the switch near moon, as soon as he closes it, then by Derek's theory, it would turn on in 1/c seconds. So by turning the switch on and off, he could essentially send a Morse code message from a distance of c metres which Derek can receive in 1/c seconds, esentially violating that no information can be sent faster than c theory. It would be very kind if you could explain that as well.
@@AxxLAfriku fariday and other pioneers of Elektro wasn’t exactly brilliant at school
I'm not smart enough for any of these videos.
Hey you're putting an electric vehicle together, how bad can you be?!
Now what is the conclusion of this discussion?
Who is correct?
But you do comment on all of them
Dont feel bad man. I try my best to be but Im not either. Lol
Jerry - "I'm not smart enough for any of these videos."
*continues making an electric HMMWV before hummer ev comes out..
I am the Abbott you mentioned in your video. I did the initial simulations and built a scale model for verification. I loved your explanation and gained a lot more insight from the clear way you explained it. I think Derek did a great job of getting people thinking about all this, and I'm delighted you are the one who actually took the time to verify my result as I didn't think anyone looked at it! Thanks again, I just subscribed to your channel.
So good reaction:))
What took you so long? Go subscribe to Applied Science if you haven't already.
Great analysis Dr. Abbott
Poynting theorem states that closed surface integral of E×H = rate of decrese of energy stored by electric field and magnetic field in the volume of closed surface minus the ohmic losses
Ohmic losses depends on the conductivity so simply I can say that power flowing out if any closed surface integral of E×H
Now in above case (DC)since magnetic field set up by DC current is constant so as the electric field. So there is no there is no propagation of E and H outside the wire... It is just a set up of E and H. The stored energy due to electric and magnetic field outside the wire is not changing with time
Sooooo.....
Poynting theorem only depends upon conductivity. Since the conductivity of the medium outside the wire is zero ,,so it will not propagate outside the wire.... Derek is only looking at E × H in this video actually E× H is not propagating in case of DC
According to him he can transmit energy wirelessly at 0 hz. Moreover he is right that current flow and energy flow are not in the same direction.....
In case of AC you can transmit t using the above concept but then again you need some waveguide for the energy flow.
@@Stevie-J I really like TechIngredients and This Old Tony. Hope you like them!
The Veritasium video feels analogous to saying "In a hydraulic system It's the pressure waves which transmit force, not the water molecules" which is technically true but you can't have water pressure without, you know, the water molecules. Granted a hydraulic system is far less complicated than an electrical one (there's no induction for one) but I still feel that is a fair comparison.
The most important difference being that water molecules*, unlike charges, can’t act on each other at a distance at relativistic speeds. I think it’s a fair comparison, and it poynts to a potential issue with Derek’s interpretation. He acts as if the EM-field is the be-all and end-all of electricity. When it’s the charges and their acceleration and velocity that defines the EM-field in the first place.
* Water might not be the best example when I think about it, as it's a polar molecule.
Exactly. Nice analogy
@@Triszious I mean the water molecules kinda do still have those electrical properties. Electrostatics mean when we think about the water molecules colliding they don't actually collide they bounce off each other's charges ;-) so you're more right if you wanted to get silly about it (like the veritasium video)
Could you think of the size of the pipe with water running at a certain speed carrying some momentum as analogous to induction? The water hammer effect seems to be very similar to the flyback voltage spikes.
It's the current that gets you, not the voltage 🤣😉
This was the exact reaction I got from my father who is an electrical engineer. The point of the video was really just to show that energy doesn't just flow like water in a pipe, but the question posed in the beginning really was quite a misleading
Funny thing is - you can transfer same "energy" in a pipe as a fast cold water flow OR with a signlificantly slower flow of hot water. And the slow but hot water will actually radiate the energy similarly to a magnetic field
Misleading to say the least.
I really really like how medy brought in an even more interesting and crazier answer with leakage current.
This video was awesome.
I am also in EE. and i was also very very triggered by Derek. I agree with Medy!!
Indeed. As an educational video, Derek did a really bad job. Actually causing more confusion and misunderstanding. Giving people the impression that ALL electric energy flows straight through the air. When in fact the vast majority of the energy flows inside the wire, or very close to the wire. Only a tiny fraction of the energy flows through the air any meaningful distance from the wire.
Viewing EM fields from the perspective of energy carried is just straight-up confusing to people, who don't understand where the concept of energy even comes from
And these people are the vast majority
"Energy", the physics term, and energy as it's commonly defined are two separate concepts. "Energy" in physics lacks physicality. You can't point to energy, and it is reference dependent. That's the whole issue with Derek's question. "Energy" doesn't exist, it's a description of emergent properties within a system.
I must say... well done! Very concise considering the topic. More than anything else, I am proud and excited that this level of technical discussion is happening with millions of people tuning in to watch.
This is the modern-day equivalent of scientists and philosophers debating on stage with the public watching. We also have popcorn emoji now 🍿. Great times we live in.
Indeed, it make RUclips more valuable. THX for that guys.
P.S.:
In Germany it is an kind of meme or insult when you have an discussion and someone say "have you learn this on RUclips university?"...
For sure - on RUclips it lot of crap to see but for my understanding there is lot more of thoroughly elaborated articles that are scientifically proven.
It drives me crazy that people are unable to tell what is bullshit and what is true... Common sense and some general knowledge and, on top of that, some research are usually sufficient to check the difference.
Always a good content, good explanations and an incredible didactic power. Well done. I'm a fan
go figure! a superior video from someone who doesn't hide behind the name "truth"
Love your videos, Jeremy!
This is one of the best videos I have watched in a very long time. As an engineer, I think, this is exactly "how" and "what" we need to teach upcoming engineers. Very well done. You have a subscriber. Thank you and keep it up.
isnt that unrealistic? this guy probably has a phd... and he is barely learning this after thinking about it for days😅
Dude, that whiteboard action was impressive, well done!
new editing skill acquired
Lmao came here for this
Yeah, I didn't realize he had magical whiteboard powers that can edit a whiteboard without touching it!
Yes
With regards to the “lies” point, I’m reminded of something my engineering professors at university would sometimes say. All models of the world and its behaviour are wrong, but some of them are still useful.
Perhaps, in many cases, "incomplete" may be more accurate than "wrong".
A model are accurate to a certain scale, then at another scale a different model will explain things better. eg: the Newtonian gravity is accurate at low gravity condition but not at high-gravity, while Einstein spacetime curvature is accurate at high-gravity condition. A model is functional at specific scale & conditions and it is against our common sense to even call the Newtonian gravity "wrong" just because there exist a different explanation like spacetime curvature.
ie. Almost all but the most detailed fluid dynamics relations. Several of the are true, but exist in simplifications that cannot exist irl. or they are simplifications that intentionally get something wrong, because the question is impossible to solve otherwise. Still the best solution we have, wherever dimensional analysis and models aren't feasible.
I took it as "lies" we tell children so we could help explain better a concept without needing for the kid to do a psychics/engineering course so they can grasp at it.
I'm an Electronics proffesor in a Mexican university and I agree, since I myself have used this quote. Though, in Spanish...
These guys are the real reason that still RUclips got some value and the amount of knowledge they bring out here is simply immense and I hope many people are getting benefited by these kind of videos and a huge kudos to such content creaters love you all.
Yes.
As a complete layman and after seeing Veritasium's second video I think I finally understood the issue. You both came to the same conclusion, except that Mehdi clarified how the details of this thought experiment were important. Derek's description of electric fields is true but it is presented as if the fully complete circuit is inconsequential.
It is important that the completed circuit wires guide the electric field in order to have a light bulb fully light up, which takes a year for a lightyear-long wire. The "disconnected" parallel wires which are 1 meter apart will cause an "immediate" (1/C sec) voltage increase in the light bulb when it is connected to power, because a small amount of energy is transmitted across the 1 meter gap. However, whether the light actually turns on from this depends on the required voltage (e.g. an LED requires less than an incandescent bulb) which in the case of an LED will only dimly light up and you have to wait for the energy to be transmitted across the complete circuit before it fully lights up. Therefore, no laws of physics were broken because none of the energy was transmitted faster than the speed of light, so our conventional abstraction of how electricity "flows" still illustrates the important parts of how electricity behaves, even if it's not a complete picture. The impression I got from the first Veritasium video was that this model is completely flawed.
Did I get all that right?
Nice 👍
So in Derek's experiment the distance between the lines was set at 1 meter. What would happen is the entire 300k kilometers of wire was laid out in a perfect circle. Hmmm....
@@BillAnt It would take the circle's diameter/c to get that first small bit of current, then it would take the circle's circumference/c to get the full voltage.
That sounds sound!
Thats exactly what I understood and I think Mehdi also shows the same concept in his follow up video
What really bugs me is that Derek calls other models "Lies".. i think that violates a very important principle of science, that all models that are supported by experiment are equally correct. It's like calling one of the many theories of quantum mechanics "lies".. it's just a different way of thinking about the same phenomenon
And Kurgesat just did a video about the "lies" they tell yesterday. Its much too strong of a word for something like this.
I like that Derek made a video that fed the RUclips educational video ecosystem with conversation points and content for interesting videos
100% agreed, veritasium really annoys me hes become the epitome of pop science when he used to make pretty good videos. I know hes just playing to the algorithm but i feel like his style makes you loose so much nuance.
@@Thisisahandle701 No. Derek does not get credit for making a bullshit video that happened to lead to good discussions when other more responsible and knowledgeable people had to correct and clean up his mess.
Well, he's been taking lots of notes from Mr Beast's notebook for the last couple of years, so obviously feeding the algorithm first and the conversation second was in the cards
Well done. His conflicting statements drove me nuts as well.
Derek suddenly unites Electrical and 3d Printing worlds on youtube eh.
The biggest mistake in that video is him saying schools LIED to us. If schools teach something that seems wrong, that's because it is oversimplified for us as young students to understand. That is not LYING. Derek is an educator and his role is to clear up the misconceptions. Leave the lies to conspiracy theorists.
without you my 3dprinter would still drive me nuts
yooo it’s chuck hiii
@@FootLettuce I saw a Kurzgesagt video earlier that used the word "lied" in the exact same sense (that oversimplification is lying), and I thought that was unnecessarily clickbaity for the same reasons.
I just realized, these videos are the equivalent of scientists/mathematicians dueling during the olden times. Back then they used letters to communicate with each other, trying to question/disprove the other's claims, or battle it out in a good old duel. Now we are seeing it happen but 21st century style!
yeah lets prepare some popcorn
Great inventions ahead.
great insight!
ps. I'v been calling them "nerd feuds" & I love them.
This is more like scientists versus engineers 🤪
Unfortunately none here are career scientist. They are RUclipsrs
I remember an experiment I did during my masters thesis. I was attempting to make a lidar based on Time of Flight and had acquired a chip (which I don't know the name of right now) that could measure time extremely precisely (we're talking down to sub 100 ps). I had a microcontroller generating a start and a stop pulse (at some frequency I don't remember, but it was on the order of magnitude of 1Hz), then I measured the difference between the propagation time of the signals. I don't remember exactly what the input into the timer IC looked like, but I assume it's some sort of MOSFET gate. Anyway, I tried with different lengths of wire and could indeed measure the lengths with the propagation time (cool!). I also happened to have a 100m roll of wire I just bought, so I tried connecting it to see if they really did provide me with the correct length. I was very surprised when the propagation time was way less than what would be expected from that 100m wire. My thoughts was that either I found a waay to send information faster than light and should clearly be awarded with a Nobel Prize... or that there was some other effect I didn't fully understand. Most likely this was some combination of infuctance and capacitance in the wire (since it was basically a coil). We could also change the propagation time by moving our hands closer to the wire coil.
So yeah, Veritasium is right that currents don't flow ONLY in wires, but the matter is more complex. Thanks for the good explanation, Mehdi!
> currents don't flow ONLY in wires
Currents *do* only flow in wires. It's the "voltages" that can span matter / space, and induce currents in other parts of the circuit.
If it’s not too much trouble, what chip did you use? I was wanting to make a TOF lidar range finder but I couldn’t find any MCUs with fast enough timers
That's because many people fail to fundamentally understand their electricity and magnetism classes. Induced current is just as important (and dangerous to screw up) as the direct path current. There is a reason if you take electricity and magnetism, signal analysis, and signal transmission, you will hate the designs from most engineers.
@@SDX2000 it is the EMF. To quote my college electronics teacher, "in relation to what" is the most important aspect to voltages. Voltage is a massive simplification of the complex effect of EMF.
@@bransonwalter5588 EMF is also a voltage. There is no need to special case it for a discussion on induced current.
Micrchip developer here: thank you very much for this video.
Whilst to most of the people discussing this, the 300.000km wire with a Lamp is a hypothetical - we microchip developers deal with "lamps" that turn on and off in fractions of nanoseconds; a speed at which centimeters are like 300.000km to a lamp - and at which the reflections and slew rates described in your video are a well-known and always considered reality.
Good point!
Average Joe: "So, how long is a nanosecond?"
Physicist: "Oh, about a foot..." 😀
@Shimmy Shai
It's a mix of maths, experience and simulation.
There are a number of RUclips videos on the topic. For example:
ruclips.net/video/4VTtkF5fzMM/видео.html
Ol
Norbert is correct.
I have to say this: Derek video did not convince me at all. No matter what everybody else was saying. Your video cleared everything and comprehensively. For this kind of problem it is not possible to disregard transmission lines theory or not defining the voltage threshold at which the lamp would turn on. Well done!
I was very distraught when I saw it first. After multiple viewings and seeing a lot or reactions to it, when I finally figured he was simply taking about the original capacitive transmission between the lines I felt better, but I was still not feeling great about it.
EEVblog's video helped a lot. And now Mehdi's video explained it succinctly.
I feel it wasn't derek's proudest moment. He made a lot of simplifications in order to make it sound shocking and counter intuitive. I think he could have done a better job with it.
yes his vid is really good..And now i will burn your brain:
Actually if you are sawing wood,the energy isnt transmitted directly by the saw itselve (not as you would see it macroscopically),but also by electromagnezic waves. Why you ask? Because the saws material is made of atoms not even touching each other, but having a certain distance. So the force cant even be transmitted by them, as you might think. The force is transmitted by the electric attraction of the protons to the electrons, plus the repulsion of two protons plus the repulsion of two electrons. So also the energy is transmitted by electric fields. Also due to little inner movements theres also a very very very tiny magnetic field+electric field created (similar to that in a crystal inside a lighter, bur way weaker) which also propegates outside of the saw,and this will also bring the energy to the wood.
I hope your head isnt smoking right now.
i thought im the only one. thanks
Totally agree with you. This and the suggestive way the video was presented by Derek really doesn't do the whole topic justice. It's a complicated topic and disregarding everything that has been taught as »lies« is just exaggerated. Also, Derek never actually said why it was supposed to be 1 / c and that the 1 in the numerator comes from the distance of 1 meter of the lamp and battery. It was really posed as a trick question because the actual background of 1 / c was never fully explained. In just the plain words as said by Derek, the units of 1 / c wouldn't add up, because it would be seconds per meter. Only if you bring in the 1 meter of distance, it starts to make sense again in the context of Derek's video.
The Veritasium's video was intentionally ambigous to spark reactions (free marketing) and views. Moving on
I just love how Mehdi explains everything in such an intuitive and visual way. Mehdi doesn't showboat to look smart, you can tell he's smart by how he brings you up to his level.
Exactly. When one truly and deeply understand a subject, they can explain it to anyone.
He reminds me of my favorite physics teacher from school
Derek is also actually smart. I wouldn't say he "showboats to look smart" he just presents the information in an engaging way for general audiences. He doesn't need to look smart because he IS smart. Both creators can be good and smart, even when critiquing eachother. Especially when it comes to science.
@@baboonaiih he smartness is irrelevant when he is trying to explain something to his audience, but he fails to do so
@@baboonaiih The way Derek fails to explain this matter to the general audience, being undeniably more cryptic than it should be (as shown by the electroboom explanation), gives me the impression that Veritassium didn't fully understand what he was trying to teach us. It would also explain why he was making deceptive, exaggerated, even fallacious claims in his video.
There is also another explanation: he didn't care enough about trying to create a good, informative video as he previously always did, but instead distorted the facts to create a click-bait, by making an extraordinary and extremely counterintuitive claim. He has somewhat done it in the past: ruclips.net/video/CM0aohBfUTc/видео.html
Thanks. A. Million! At 13:05 into the video I suddenly fully understood coaxial cable impedance! You know; 75 or 50 ohms normally. Just great! 😁
This is why I love the science/tech sphere on RUclips. Love the interactions between channels and furthering of critical thought. Great video
This should be most people's reaction but for some reason the commenters here turn it into a hate filled rage boner battle.
@@baboonaiih people who truly understand know the sheer stupidity of Vertasium and many of his videos. So they comment accordingly. People who have passing interest can be spectators, be satisfied with Vertasium stupidity, and make comments like yours.
Let me give you an analogy. Suppose a RUclipsr made a video that a tire rolls down hill because the earth magnetic field pulls on the steel radials and not gravity. Would you be as kind to them, when you *know* the truth: gravity.
Now imagine 6 million people going along with the RUclipsr's stupidity, do you simply say oh well, it's all opinion and just a bonner battle. If you do, go stand in line for the stupid bus. It's getting full and you want to be sure you get on it.
@@joeboxter3635 so you think harass someone who made a wrong thing but sincerely sorry for it and will fix it in the future is cool lol? If you think you haven't done anything wrong in your life then you must have done nothing lol because people only not made mistakes when they did nothing.
P.S: also your analogy is shit
@@baboonaiih And that's why we've been tricked by left vs right politics for so long
@@lovell8983 He has never admitted he made a mistake. In fact, he has doubled down. So don't even go there.
And this is not the first such video. He is laughing all the way to the bank having made $30000 and counting on this video alone.
Why does he have to do anything but take down video, if he admits he was wrong. And of course people said he was wrong around the 1 Million mark. He has made additional $25000 leaving it up, that's why.
It's not harassment. It's speaking the truth. So just take the stupid bus. Let people know from "go" Vertasium is wrong say so. Just like EEblog, Electroboom, and handful of others who are calling Derk on his foolishness.
The fact that you don't follow the analogy just says that you belong on the stupid bus, BTW. It's an example just like Derek's, where gullable people would fall prey for a fictional answer. And indeed there are many flat-earthers who have fallen for the magnetic explanation.
I love that this almost makes a perfect 3 part series with the original video and Kurzgesagt's video about "lies". Such perfect timing.
Ooohh, that's why i feel a bit familiar. because i just watch that video too 🤣
This comment has blown my mind a little bit, thanks
it's 8:00 am here and it's the perfect video to see in the morning 🌄
Oh my god I was going to leave a comment and then you showed the two giant loops and I HAD to. I ran this experiment last weekend with 1km of wire and a ~20ns rise time “switch” and tried a bunch of variations including the two big loops - spoiler alert - the two loops makes the effect completely vanish within my ability to measure (without changing load resistance). I’m hoping to edit that all up ASAP but I had a question - in your analysis and in the great eevblog video, you both use the classic transmission line model with inductors and capacitors, and state that the coupling between the wires is predominantly capacitive, but in this case where you are only actively applying a current in one wire, should we be worrying about inductive coupling between the wires? Like a straight-line transformer? Like the capacitive effect, it would die out as soon as the current hit steady state and the magnetic fields weren’t changing, but I haven’t yet run the numbers to know if it’s super tiny relative to the capacitive coupling.
I thought your analysis was fantastic, and now that I’ve done it for real I can confirm the traces you drew were extremely realistic. I’d add that on a wire that long in the real world, “any current” is basically all the time - especially in the wind… adding to your “always on” conclusion. There was enough noise that the scope was actually super hard to trigger…
Thanks!
Waiting for your video too
Looking forward to seeing your analysis too!
would just be waiting to see results of your experiment
I don't think the inductive coupling will be significant with 1m of separation, but it would be interesting to look into.
"I bought a kilometer of wire to settle a physics debate!"
I work at a high voltage company. A good explanation of inrush this is. We still don't have long 100km 380kV AC cables, because the initial voltage is too high when the cable is switched on what would create a fault in the insulation of the cable, or in the the installation.
Oh well done, this is by a LONG way the best presentation of this I've seen so far. I've been pulling my hair out for weeks. I've been utterly astonished at the uniformity in misunderstanding that has existed on this topic since Derek's video. Even scientists with a PhD have overlooked the basic things you pointed out with such clarity in your video. I'm so pleased there is now a video by someone who knows what they are talking about that is as comprehensive as this.
There's a few other topics you could have covered, such as the Poynting vector and superconductors, how the potential energy in the vicinity of the bulb (carried there by the wires) is transformed into light and heat energy in the bulb and the Poynting vector corresponds precisely to this in the vicinity of the bulb, how radiative energy is distinguished from potential energy in the electromagnetic field, how ohmic heating works and how the Poynting vector points into the wire (at the surface) when the wire is not superconducting, how the speed of transmission is related to the dielectric constant and so on. But you covered the most important topics for understanding Derek's original video, which I consider to be quite misleading.
Yeah, PhD doesn't mean that people keep knowledge they've gained close to their heart
@@blinded6502 doesent Mehdi also have a PhD?
@@blinded6502 Those people with PhD are not wrong, but they jump right into the Poynting vectors and deep physics, ignoring the big picture. They have pre-existing knowledge about these things, they already know the good explanation, and that’s what they agree with, not what is in the video.
They don’t understand how confusing it is for someone with “only” high school level knowledge, especially when that high school was a decade ago.
While watching Derek's video i thought about my transmission line class in college. I remembered very little of it but his explanation just didn't seem right. ElectroBoom brought it all back in a rush of educational bliss! My mind is now at peace.
Electroboom, I'm a retired electrical engineer. I love your video. I wanted to say, importantly, the word is impedance NOT impotence!!! Yours is the third of three videos I've watched on this. First was Veritasiums, then Dave at EEVblog, then yours. Dave said that we engineers think about things differently. That we have tools to analyze things and validly track physics and the rules of science. You fellows have collectively reminded me of much of the complexity we were trained to understand and analyze and calculate. I've much forgotten what I was trained and educated to deal with. I've been so browbeaten by the mindless politics and public chaos of people and the media news etc. I've forgotten the promises of my youth and education. RUclips, multimedia and Internet is a terrible way to waste a capable mind. You've helped to retrieve my past capabilities. Thank you. Amind is a terrible thing to waste, and you've given me a wake-up call.
He's saying 'impedance', not 'impotence'. He's just placing the stress on a different syllable. 'ihm-peed-ANCE' instead of 'ihm-PEED-ance'
7:34 blew my mind, the transmission line analogy blew my mind even more. Now I feel disqualified holding an electrical degree. When I watched Veritasium's video it made me more confused; while your video actually gave a very detailed picture of what Veritasium is trying to describe, props to you ElectroBoom :)
The transmission line analogy is only valid though if the two lines are close to each other in order for the cross capacity to exist at a reasonable value.
@@embeddor2230 No, only valid if the space between the two wires is far smaller than the length of the wires. Which it is.
2-wire lines are COUNTERINTUITIVE. Also, we're NOT allowed to ignore the inductance per unit length. That creates the magnetic part of the EM fields.
For example, transmission-line calculator says that 1mm wires spaced one meter apart have a line-impedance of 911 ohms. Or bring those wires only 1cm apart, giving Zo of 360 ohms. So, going from one meter gap to 1/100 meter only changes the characteristic impedance by less than three! (Or, go from 1M to 10M spacing, and the Zo goes from 911 ohms to 1190 ohms, only a 30% increase with TEN METER SPACING. If Veritasium used an LED, then it would immediately light, even if the space between wires was 10M rather than 1M.)
Imaginary electrons LOL. Funny dystopian pseudoscientist "electroboom".
@@embeddor2230
> The transmission line analogy is only valid though if the two lines are close to each other
So you appear to be saying this? ...if two long wires are one meter apart, they don't form a capacitor anymore. The gap is too large! Also this: if a big wire loop is made 1M in diameter, it stops being an inductor. The wires are too far apart from each other!
If that's not what you're saying, then your claim appears to be an unsupported newbie misconception. As wire-gap increases, and if the wire diameter remains the same, the Zo line impedance doesn't increase as inverse-square or inverse-cube! These lines are closely coupled (very long, where the 1M gap is almost insignificant. That's why we can apply transmission-line physics.)
Transmission lines are COUNTERINTUITIVE, and if we aren't RF engineers with some EM fields/waves classwork under our belts, we're going to be trapped in newbie physics-misconceptions. For example, how does the Zo line impedance increase, as we separate the wires? Start at 1cm, using Dereck's cables (which appear to be roughly 5mm diameter.)
Gap size M | Zo in ohms
0.01 - - - - - - 158
0.02 - - - - - - 247
0.05 - - - - - - 359
0.1 - - - - - - 442
0.2 - - - - - - 525
0.5 - - - - - - 635
1.0 - - - - - - 718
That's from the online calculator at Clemson TL_calculator...
cecas.clemson.edu/cvel/emc/calculators/TL_Calculator/index.html
To bad Veritasium didn't have his wires be 10M apart! With 5mm cables, the Zo is only 1K. Then use a 220VDC battery, and light up a bulb, where the billion-foot lines are only putting 2K ohms in series with the light bulb.
.
veritasium is a fool as he not taking impedance values into the equation..light takes a second to reach the moon.current flow will be slower due to the resistance of the wire at power up.
If I had a professor like you in college, I would have been an electrical engineer and not a mechanical engineer. It's so facinating and amazing and you do such a great job of explaining it!
It really makes all the difference, doesn't it?
You are an electrical engineer and don't know it. There's a LOT of overlap. Many of the equations and concepts are the same. Enjoy!
That explanation is pure gold. Should be listed as recommended literature in all universities with electricity related faculties.
Well done. I think you clarify what Veritasium messed up. You give a proper model for the problem.
Being an electronics engineer myself, seeing Veritasium's video left me with some thoughts of "hmmm, I don't know if that's that..."
Thank you for showing things were in fact the way I thought they were.
I wouldn't say "in fact"
Me too!
@@acommonman7950 I'll trust the thorough explanation of an expert over the simple doubt of a common man.
@@EaglePicking Trust Veritasium.
Same here!
Thanks for this brilliant explanation. I like how you point out the "transmission line" property of the setup. As an RF engineer I tip my hat :-)
Another RF engineer here. Some thoughts that I want to shared wit you: The large peak Electroboom saw in his LTSpice simulation at t=0 is due to the capacitance of the TX line (as he mentioned), which is a short-circuit for the high-frequency content of the voltage step created when closing the switch. I think that in reality high frequencies are radiated from the battery wires to the lamp wires (a.k.a. a spark TX ) and a small amount of energy is picked by the lamp. That energy arrives 1/c seconds after switch is closed. It is just not enough to turn on the lamp, but I think that pulse (or transient) is what Veritasium was addressing as "lamp on"
I took a rf course and I'm glad it lays out a very important foundation for me to understand pcb level transmission line stuff and of course questions like this.
Enjoy your small victory engineers; Physicists rule!
@@Ducktility Your comment is how to tell someone is still in school and isn't yet a physicist with an engineering job. Seriously though most physicists I know still consider RF black magic. It is one thing to know the fundamentals on a base physical level, its another to make it happen.
@@Noubers You don't really understand fundamental research, do you?
I'll give you a small example:
Theoretical physics: Hypothesize electrons
Applied physics: Discover and demonstrate electroluminescence
Engineering: Improve LED efficiency and make it useful to the world.
The thing I learned in uni is that "energy" is literally anything that _can_ do something. A ball on top of a desk has energy, potential gravitational energy. So yes, the EM field carries energy. But a moving electron creates EM fields that carries energy. So, in a way, electrons (moving ones) are carrying energy. It's a useful abstraction!
Derek's video also rubbed me the wrong way, especially how the light turns on at _any_ energy level. I figured that in that case, the distance from the switch to the light bulb would be significant, since it should carry _some_ energy, or something like that. I think the general premise of his video is good, but the dissmissal of abstractions and trick question did a disservice to it, in my opinion.
Loved this one tho!
ahahaha astolfo funny words
His video also bothered me because his answer would be the same (1/c) if you had an open circuit at both ends of lines. It all boils down him being technically correct but pretty wrong in practice. It also doesn't help that he's basically clickbaiting and fooling a large audience into thinking they were taught wrong their whole lives.
One of my best physics teachers in uni used to tell us that energy is just a "conversion currency" between different phenomena, once again, a useful abstraction.
I don't know if I'm being naive here. But I think the point of Derek's video was to show that energy is carried by fields, The trick question and the exaggeration are means of engagement. And I think this because of his videos on clickbait and viral videos.
what is good: it creates a chain of videos that respond to his, and leads his viewers to these videos. Since the alghorith tends to couple videos of simmilar topics and audiencies
what is bad: He could have achieved the notion he wanted. That energy doensn't goes through wires (wich we done well), and after that, actually ground his clains, remove te hyperboles, and explain that distance hardly relates with power.
The problem with his aproach in my opinion is (if this was his aproach): his original claim, that we were taught to us is wrong, what he ultimatelly did, is also wrong, but in the reverse direction. The naive defence that I kinda have is that his intent is to create more videos about, and simultaneously raise awareness to the subject and other creators, but how could someone judge the sucess of this (if is really his intent) and wouldn't it fu** his credibility if after the video you don't know if he was tolding the truth or running some kind of community awareness experiment?
@@dan1RR I make your words mine, couldn't have put it any better.
One thing I'd like to add is about the "you were taught wrong" approach. While it is true to some extent to say that and brings in views, I'm much more fond of kurzgesagt's approach. Which is to say "you were taught wrong, err, sort of". The "lies" we're taught are just simplifications and abstractions of a messy reality, so that we can slowly build up our notion of the universe.
Derek just says "you were taught wrong" and doesn't elaborate any further. It's almost paradoxical, he is diving deeper into a subject while also staying at a shallow level. Which is why I believe it was a disservice to himself.
I hope my point makes sense ;w;
Very good video. Except at 1:32 you should have just said "seconds" instead of "value of time per second"
This is great. I am also in EE and I agree with everything said here. Derek’s. video is a bit incomplete which is rare for him. He did deserve this.
He talked about demonstrating this with an experiment, so I wonder if he was being intentionally vague in order to make a follow-up that explains things more thoroughly.
I don't think it is rare for him.
@@Elrog3 any other vids?
@@Elrog3 damn really nailed him... maybe???
@@Harambe8 A month ago he did a question in a community post and a video about a string hanging from a helicopter. It was an inadequately defined question.
I remember there were some about cosmology or particle physics that didn't sit well from years ago.
Its not always the basis of the whole video, but it does seem about every other video (that I watch) he will say something questionable.
I watched Veritasium's video when it came out, and knew I had only to wait for your excellent response. Is this (friendly) rivalry going to end with you both teaming up to create a real ~300,000km long circuit?
NNNNOOOO! :)
@@ElectroBOOM free energy?
@@ElectroBOOM As electrical engineering student, I really hated how people fanatically believed that his explanation is 100% right and who disagrees is just stupid.
You just need a couple of meter of a cable triggered source and fast scope. The delays in the signal will be clearly distinguishable.
@@ElectroBOOM Don't you have like 150,000 km of ball-chain already laying around from your last controversy? :D
Kurz did a very good video on the "lies" of science communication's required simplifications of complex topics. But the way Veratasium said that we were taught "lies". Annoyed me a lot especially when he hyper simplified his example down and ignored so many potential losses or other important variables in his explanation. Which as you have shown in this video is a "lie", ie simplifcation of a topic.
He took issue with a "lie" then explained why he thought it was a "lie" by "lying" about it? Why is it not as clear if not clearer to explain that its a nessecary simplification for base level understanding of electricity? Rather than to give the impression that people are being taught falsehoods. Potentially damaging peoples trust in the education they have been given on other topics.
Amen. His video leaves people with two false impressions:
Wires are irrelevant
Science lies to you
Kurz calling simplifications for lies is really handing a big point over to the weirder side of the "do your own research"-group.
Well, he did the exact opposite to what Kurz is trying to do - he took a pretty simple and quite valid model and complicated it with what he presented as "fields and vectors magic"
Yeah exactly quite disappointing to say the least
This is especially gross considering the massive amount of science denialism going on today with climate change and covid. These people know better than to label these models lies.
What made me laugh most is I instantly picked up on the fallacy of Derek's idea that the chain in the pipe was a poor analogy when I saw his video. I tried to imagine an engine that would work with such movement, but got bored trying to figure something out. The simplicity of a saw cutting through wood was like a smack across the face.
did you see the second video of veritasium?
Thank you for setting the record straight. Derek's was indeed a trick question based on language. "Turned on" is a concept that we associate to the circuit being at operating current. He should have said "receiving any energy from the battery". Which also the rocks did, by the way.
Exactly even worse he drew up the problem to SEEM like it's asking about DC steady state but OOPS it's a transmission line problem! If it was really asking about the transient state any person correctly modeling the problem would draw the appropriate distributed model of the transmission line. Unfortunately oops he forgot to draw the LC network! That would be a great way to get fired for incompetence in the real world but like you said he did this all intentionally for attention.
Yes this was not very impressive by Derek. Either he doesn't actually understand what happens, or he deliberately fools the audience. In any case, most people will not be any wiser from his video.
He seems to like to do a lot of this type of trick with his video titles or main questions raised in the videos themselves. He seems to enjoy being like "See? Nearly everyone is wrong about this thing!" due to some trick of phrasing/language.
@@DeathBringer769 True. Typical media sensationalism, actually.
@@EaglePicking Known as "Clickbait" Bread and butter of the RUclips (well any media) titles.
I love the pun in science where a mathematical vector points in the direction of energy flow was pointed out by the scientist John Poynting and for which we credit him and call it the Poynting vector.
You may also like: symmetries in manifolds, the Killing vector
en.wikipedia.org/wiki/Killing_vector_field
Not as funny, but there’s also the Shockley equation for diodes
well guy had a poynt to make \(Oo)/
he was the first to orient his finger in the direction of something of interest, before that people just waved their fists and shouted
@@WaffleAbuser People usually take it the wrong way though.
As someone who took one course of electrical engineering in college, I also thought the Veritasium video felt like a trick question and left me kinda confused. This video made it clear what was actually happening.
yeah.. maybe theoretical physics mixed in with real world application.
I love it when someone makes a video/hypothesis about science and people, scientist, engineers from all over the world try to replicate the idea to try to prove/disprove this idea. It's the same concept used in academia but making it accessble to the world. +1 to youtube.
I am an electronic engineer and Dereks video made me question my education. I think of that as a good outcome. And I immediately wrote he was wrong. I am so glad Boom made this.
I Indian?
same happened to me, but i am salf taught on electricity and electronics...i got so lost on his video that i wrote comments to disagree with it...for me the light only turns on when enough current flows to make it glow, he never referred to the wires as big antennas or a capacitor and he never mentioned leakage current, he also never mentioned background fields and he never mentioned how irrelevant all of that is on a frickin DC 12 lightbulb circuit, if he explicitly mentioned that, then i would understand the subject instead of wasting all my brain cells to find ways to disagree with him
Excellent explanation. And the opposite will happen when you switch it off: the lamp will not go out instantly, because of the stored energy in the capacitance and inductance. Brilliant. I even dare to say that a similar effect will happen with mains AC when it gets switched off: ringing needs to die out, or there's momentum in the rotating 3-phase power grid. At home when turning off the light, it gets dark instantly. When a power outage happens because of a grid failure many miles away, the light will fade out in a fraction of a second, instead of going dark instantly. Seen it with my own eyes.
The biggest thing you've demonstrated here is that the field strengths are strongest when closest to the wires. That alone clears up the main issue with Veritasium's video I think!
I think the main issue with his video is that he said that electrons moving through a conductor is not how energy is carried in a circuit. It takes energy to get the electrons moving and without those moving electrons no energy is transmitted. Sure, they do so in the form of EM fields, but it's the moving charges that generate those fields. It's like saying a hydro dam doesn't get its energy through the movement of water, but instead through the influence of gravitational fields.
Yes, Veritasium confused 2 different things:
- Electricity is propagated around the wire, but still close to it, following it.
- If you attach a battery and a switch to a piece of wire, and start switching it (like a Morse code), you created a radio transmitter.
One is good for transferring electric energy, other is good for transferring information.
Agreed. Derek implies that most of the energy is flowing through space, which it's not. Those fields are going to be concentrated almost entirely along the wires. It was also really wrong for Derek to say that "it's not what's happening in the wires that matters". If that was the case, then why would you need wires at all?
Yes, Derek's argument was all qualitative while leaving out ANY quatitative qualifications which usually leads to severe misunderstandings and wrong conclusions. Sometimes you really have to do-the-math to understand what's really going on.
@@jasonpatterson8091 Oh man that hydro dam is a great analogy, thank you
The fact that millions of people are willingly watching these kinda videos shows that we can teach it in an interesting way and school isn't the end of the story
It shows that pop sci entertains but doesn't truly educate. It's free because it's of little value but for entertainment. You sound like sour grapes.
The editing is on another level, amazing to see how the channel is developing over time
The demonstration that the LED turns on without closing the loop for a high frequency signal was brilliant! Amazing video, as always!
i still cannot wrap my mind around how exactly is that possible. Can someone explain in different words whats happening there? Or explain it like im 5 or something
@@bartosik321 AC current is wack and doesn't need a wire to connect it to ground, it'll find other ways to reach ground through the air
that was some black magic ive never seen before
Poynting theorem states that closed surface integral of E×H = rate of decrese of energy stored by electric field and magnetic field in the volume of closed surface minus the ohmic losses
Ohmic losses depends on the conductivity so simply I can say that power flowing out if any closed surface integral of E×H
Now in above case (DC)since magnetic field set up by DC current is constant so as the electric field. So there is no there is no propagation of E and H outside the wire... It is just a set up of E and H. The stored energy due to electric and magnetic field outside the wire is not changing with time
Sooooo.....
Poynting theorem only depends upon conductivity. Since the conductivity of the medium outside the wire is zero ,,so it will not propagate outside the wire.... Derek is only looking at E × H in this video actually E× H is not propagating in case of DC
According to him he can transmit energy wirelessly at 0 hz. Moreover he is right that current flow and energy flow are not in the same direction.....
In case of AC you can transmit t using the above concept but then again you need some waveguide for the energy flow.
Basically, there is a parasitic capacitance between the separate loops. So, the higher the frequency, the lower the parasitic impedance and the signal passes through the air (dielectric) and reaches the other wires.
Excellent explanation
says timebucks, of all people
This makes so much more sense than the Veritasium video! I actually had the same thought about the circle wire path.
I watched Veritasium's video first, and, while confused, I learned the interesting idea of energy flowing around the wire. After watching yours (despite getting a bit lost in the second half) I understand better how it actually works
6:45 "...a hundred times weaker". Can you explain how that works, as you can't quantify weakness? Or do you mean one hundredth as strong?
@@bremset I think that’s the commonly agreed understanding of that phrase. When the adjective describes getting closer to 0 of some value, the multiplication uses the inverse value. Becoming weaker is trending in the direction of 0 strength, so 100 times weaker means 100 times closer to 0 strength, or a multiplication by 1/100.
This is language dependent, because you have to already agree that weakness isn’t quantifiable alone, but only by reference to some amount of strength. 0 weakness doesn’t fit into reality as well as 0 strength does. Just like how infinite strength is unrealistic but infinite weakness is realistic. You can argue against these assumptions scientifically, but to understand the phrase “100 times weaker” as it is commonly used, you have to start by agreeing with them.
@johnnytheprick i dont know. I tried to post in the main thread. But now you've replied to weirdo yourself 😅
11:15 and 12:40 is exactly how telecoms people (like me in a past life) see current flow in a pair of wires. Along the way, you beautifully explained the concept of Characteristic Impedance.
"It's the field that carries the energy, not the electrons" is the 2022 version of "It's the current that kills, not the voltage".
I believe that ElectroBOOM is trying to explain the practicality of the theory rather than the theory itself, which is amazing. While Derek is trying to explain us the theoretical part of this idea.
So, I recommend that both the videos are correct but its just 2 ways of looking at the same problem, and can get different answers because the conditions in the way we look at the problem has changed.
it's like looking at a sheep(the problem) being colorblind and another looking at a sheep wearing colorblind glasses although he/she can see very well without the glasses.(Not being biased or sarcastic!)
But both the videos express great ideas to think of and learn,, THANKS both of you... And I am subscribed!!😃
For future reference it might be interesting to point out that LTspice has a dedicated component model for ideal transmission lines "tline" where the only parameters are line impedance and transmission delay - you can use that to simulate the 1s delay (or any other delay for that matter). And of course for more accuracy there is a lossy transmission line model "ltline" - which is described by the lines inductance, capacitance and resistance per unit of length and the line length. Either could be used to simulate this exercise.
Ah! Your channel is wonderful!
Really love and appreciate the editing here, especially with the white board scene! Made things really fluid and in-pace while also being digestible and easier to understand. Thank you Mehdi!
Thank you for making this video. Derric's video didn't sit well with me, and luckily there were many in his comments' section that pointed out this very issue, but it's nice to have your detailed explanation to really iron out the caveats.
It doesn't happen very often, but sometimes I am hit with a strong sense of "man, this guy really knows what he's talking about"', thanks Mehdi
But he’s wrong.
Sometimes it might seem like person knows what he's talking but they're bullshitting you. Not in this case, Mehdi is actually right but others might be wrong. Like Veritasium who seems like he knows what he's talking about but he's been straight up wrong few times
@@realdragon I heartily agree, but of course there is a difference between talking out of your ass and making an honest mistake.
Considering Veritasium's sportsmanlike acknowledgement that his brevity sacrificed precision, he doesn't seem like a bullshitter to me - though I am not familiar with his content beyond this reply
@@cryhavocandletslipthedogso1873 He might not be bullshitting on purpose but he has wide audience and that audience who doesn't know any better believes him.
He also made video of why water running water bends when you put electrically charged object near it and he wasn't just mistaken, everything he said was straight up wrong and it's easy to prove too
@@realdragon Alright then, thanks for letting the world know
Veritasium made it explicitly clear in earlier videos that they optimise their content for the RUclips algorithm and to maximise viewer numbers, and prioritises this above the desire to provide content that educates.
The Veritasium video was carefully calculated to be click-bait and cause maximum outrage and confusion in order to boost viewer numbers.
By this metric, Derek's video was a highly successful money maker.
This profit was however achieved at the expense of annoying everyone who already understands transmission-line theory, and insulting engineering teachers by calling them liars.
Bingo. Veritasium used to be good, now it's click bait trash.
Echoing this. Veritasium changed from education to clickbait several years ago now.
I remind you all that it was his thesis that tricking people into the wrong answer would lead to better learning. So he went asking people on the streets and shows the wrong answers on the video, to then show the explanation. Baiting and triggering question always were in him.
AGREEEED. YOU NAILED IT. SO TRUE.
Lmfao this was not even close to what he said in his video on clickbait 🤡
Best response to this so far. It's been occupying my mind for a week or more, too. Those simulations answered a lot of the outstanding questions I was still wrestling with. This video also addressed some of the things I disliked about how Derek presented it. For example, Derek's presentation of the material seems to imply that the wires are immaterial, which raises the question of why do we even need wires at all. The answer is exactly as you presented. The wires are devices for constraining the path of the magnetic field and by extension, the energy flow to where we need it. Great job!
Does 'the wires are devices for constraining the path of the magnetic field and by extension, the energy flow to where we need it' mean that the energy flows outside very near the surface of the wire rather than inside it?
Poynting theorem states that closed surface integral of E×H = rate of decrese of energy stored by electric field and magnetic field in the volume of closed surface minus the ohmic losses
Ohmic losses depends on the conductivity so simply I can say that power flowing out if any closed surface integral of E×H
Now in above case (DC)since magnetic field set up by DC current is constant so as the electric field. So there is no there is no propagation of E and H outside the wire... It is just a set up of E and H. The stored energy due to electric and magnetic field outside the wire is not changing with time
Sooooo.....
Poynting theorem only depends upon conductivity. Since the conductivity of the medium outside the wire is zero ,,so it will not propagate outside the wire.... Derek is only looking at E × H in this video actually E× H is not propagating in case of DC
According to him he can transmit energy wirelessly at 0 hz. Moreover he is right that current flow and energy flow are not in the same direction.....
In case of AC you can transmit t using the above concept but then again you need some waveguide for the energy flow.
@@jakkank That's what Mehdi's talking about between about 6:30 and 7:10 in this video. The magnitude of the Poynting vector is proportional to the product of the electric and magnetic fields. The Poynting vector shows not only the direction of the energy flow, but the magnitude of the energy at that point in space. For a DC circuit at steady state, the magnetic field is strongest just outside the surface of the wire and drops off in proportion to the inverse square of the distance from the wire, so the energy flow will fall off fairly rapidly as we get further away from the wire. Even for the relatively low line frequencies we use for power transmission (ie. 50-60Hz), this will still be generally true. We will leak a little more energy into the wider environment, but most of the energy will be flowing close to the wires, most of the time. There are caveats to that statement, which is why things like radios and microwaves work but that's also why we don't make our transmission grid like a radio and operate it at a relatively low frequency. That way, most of the energy flows close to the wires to the load where we need it.
I love how some of the best tech RUclipsrs are getting into debates, ultimately educating us in a more in depth fashion than if it were otherwise. As long as it stays into the domain of constructive criticism, these videos will be some of the best content around. Thanks @electroboom and @veritasium!
Fr I really love how a video moved others to make more videos about it to find the truth and I an interesting wsy
Except *Derek's* video was pure garbage; really misleading. SMDH
Derek is not a best tech RUclips, not even a little. If you watch his videos he wanna look like a star talking to people to show them how stupid they are, and trying to learn from professors. Its a personal diary about himself, how he risks his life, how he wins a debate etc
The downside of the youtube debate format is that smaller channels have less (sometimes no) visibility, so even when they are correct, the lay public never sees their corrections, and only see videos from large channels, even when the content in them is misleading or just plain wrong. Not all viewers will dig through the myriad response videos to find the answer, and even those that do may not have the scientific or technical background to understand the arguments being made.
@@Vasharan Absolutely correct. That's why rich people who run moneymaking accounts like Derek's have a very big responsibility, and their negligence is rightly criticized very harshly. Clickbait BS shouldn't be rewarded.
Omg, this is educational and entertaining at the same time. Brilliant!
Оо,привет👋🏼 твои ролики не менее увлекательны👍🏼
Ohh cut the crap! Just kidding, I agree.
Your videos look interesting 👀 sadly I don't understand Russian
Do you know what else is Brilliant??!
That's right! this comment is sponsored by brilliant!
*This comment is sponsored by Brilliant*
I don't know if I learned anything about electricity, but I do check my closets for lost mothers now.
This is actually quite a common phenomenon.
Many popular wide-topic blogs (sci-pop included) seem at first really comprehensive, until they hit one's specific field of knowledge, at which point one realizes they are superficial, inacurate and often misleading concerning even essential details.
Thanks for clearing that up. I'm a retired Professor of Physics and Electrical Engineering and struggled a little with Veritasium's explanation. You filled in the gaps and turned on the switch to my full understanding.
The analogy with the wood and the saw is great. I thought of something like this, but that one pretty much nails it.
I SAW what you did there!
@@sirrathersplendid4825 damn you dirty mind :P
It's misleading.
@@sirrathersplendid4825 damn you guys are SHARP
@@n0nenone WOODn’t you know it? I can appreciate your SERRATED humour.
The more accurate transmission line simulator is currently what I'm researching for my master's! I'm very happy about this video as Derek's video did make me feel uncomfortable with regards to how small the amount of power the light bulb would receive, which you address in this video. Derek's video does well to highlight the idea that electricity is in fact a travelling electromagnetic wave. I think both videos work well together! So happy to have all this relevant content
Both correct, but from different viewpoints :-) Certainly both are Astronomical Educators++
@@alanclark988 and you too Prof are an amazing educator! Definitely one of the best teachers I have ever had !!
16:44 the same conclusion as Veritasium second video and Alpha Phoenix experiment. But different theory. That nice to have cross explanation.
10:35 makes what Derek's video was trying to explain so much more clear to me. After I finished his video I was still kinda scratching my head. Seeing it this way makes the Poynting vector explanation seem more like a red herring for the _reason_ and instead just a mathematical representation.
That is because when one truly and deeply understand a subject, they can explain it to anyone. I think Derek's intentions were not only to teach something to their viewers, but also to get more views, sadly.
The NYU Quantum Lab has a good discussion on this - while the math works out, as Feynman argues it's rather questionable to interpret the Poynting vector as showing energy flow.
I saw the trick question AND the errors in his explanations all throughout his video... but I work with long transmission lines, electro-magnetic coupling and currents all the time through my occupation. Derek's video struck me as being both partially correct and yet partially wrong at many levels. Thankfully, your video elaborated on most (if not all) of the errors.
Yeah, I worked on them in collage 8 years ago, and had the exact same reaction: Which was, that's one way to think about it, but it's not the only way, and both are correct in their own ways.
@@medleyshift1325 If Derek is right, then he found a way to transmit information faster than c. Sadly, that just is not possible. Derek is wrong.
@@taylornate2 How would that be faster? You are mistaken.
@Cekia Selmi ♋️ - Do you not realize that no one gives a crap about your website?!!
@@Supernov4 because we can apparently learn whether the far end of the circuit is open or closed faster than it would take light to reach us from that distance
As an electrical engineer myself, I knew SOMETHING was wrong with Derek's video; I just couldn't pin point exactly what. Thank you for making this very detailed explanation!
Put your diploma down sir. Any respectable electrical engineer knows this.
@@lazar2175 well most engineers aren't familiar with transmission lines, just sayin.
The problem is that he implies that power transmission is done in the same way as radio transmission.
@@joefuentes2977 Dude, he called himself Electrical Engineer. His literal job is to design power transmission lines, transformers etc.
He must know this stuff - I don't believe a single college will let you graduate with EE diploma without knowing this. Hell this is high school stuff, he just worded it super weird and used a trick to con people into assuming a false answer, as explained by Mehdi. Anyway, a real EE engineer should be able to see through it.
@@lazar2175 People study one field, and then start to work in something else, it happens. Stop trying to find flaws, nobody cares.
Thank you so much for this video! I watched Veritasium's video and was left feeling that everything I had learned about electricity was wrong and I was never going to understand how it really worked. After watching your video I have come to the conclusion that electricity is more complicated than I first thought but I should probably go back to thinking of it practically as electrons flowing through a continuous circuit as this has at least so far stopped me getting electrocuted and you are a special kind of genius to be able to not only understand all of this but also explain it in a way that is so entertaining and doesn't make me feel like an idiot.
There is practical and there is theoretical electrics. Practical is more than fine because a massive amount of assumptions can keep you safe. That being said, you don't violate the rules in those cases. Theoretical electrics tells you that static is not random and everything is calculated and nothing is too small.
Oh my GOD, this is brilliant! He literally answered ALL the questions I had crop up during the video! This is actually WAY better than veritasium's video
@johnnytheprick stop
Yeah I'm an engineer and Ive watched all his videos and recommend him often cuz Electroboom is the best!
It's almost like it's better to leave complicated topics to skilled professionals
@@unlink1649 Shocking, right?
@@unlink1649 but I love th fact that because of his videos. I found more good channel.
Dude, such amazing editing in this video! The sound effect as the field began to propagate, the "Don't watch if you have diarrhea" in the disclaimer, the elevator music from Mass Effect... just amazing!
Yeah the whole trick was to conflate 'immediately' (time), with sensitivity (power level).
I think instinctively most people would have realised a switch being closed can affect a neaby device without being physically connected, but can't usually provide a large quantity of power without a decent cable connection.
There was comment which was like, if this is how it worked then electronics could not function
This actually reminds me of the days when I was twisting my head around RF circuits :D All of this is known and I really appreciate you pointing out the workable models to think about this.
Wow, I feel like I'm watching an old-school Electroboom video with no mercy given for viewers who still need to do their homework. Fantastic.
I did sorta expect a homebuilt circuit, though, that used components to simulate Derick's thought circuit.
Not to measure 1/c action, but just because.
I am sure he'll build one as soon as he finds wires with no resistance. :P
Derek's explanation dismisses the principle of locality by suggesting that the fields alone transmit energy. The fields need free electrons with which to interact and they have to be fairly dense to transmit measurable amounts of energy. The chain analogy is apt because each link in the chain pulls only against its nearest neighbor.
Felt like there was something wrong with ignoring the electron as the carrier of energy. Dismissing locality.... that was it.
I think that in transmission there is locality that can connect through air as well as wire and it is all one thing... but where he's wrong is thinking that the Poynting vector equation describes an evolving circuit. It describes what a circuit evolves INTO assuming that there is an equilibrium to find. He's using an equation in a completely wrong context.
nice
That's the principle I was looking for! My biggest problem with Derek's explanation was that while the source and load are only 1 meter apart, you can't have the energy flowing all the way _around_ (half) the loop in 1 m / C seconds without information traveling faster than light. (Though I don't think that was what Derek was saying at all.)
Imagine the switch being half-way along one side of the loop. Assume you're observing at the load, but somehow know when the switch is thrown (perfect synchronized clocks, perfect actors, and a pre-agreed time to the nanosecond -- or just go with "magic"). The switch is 1/4 light-second from the source and the load. Thus, it takes ~1/4 second for the information about the closed switch to propagate back to them, inducing the current locally and turning on the light. It doesn't matter whether you model the electrons or the fields as carrying the energy here, the result is the same: the light cannot turn on in less than 1/4 second. Otherwise, we could transmit information faster than light as long we had a long enough wire.
Frankly, because of this, I'm struggling a bit to mentally model how the light comes on in 1 m / C seconds here at all, but it kind of made sense to me intuitively until I started thinking about it like this. I'm using the assumption that having the switch anywhere is equivalent, but I think that may be wrong due to the extreme nature of the circuit (i.e. this is theoretical physics, not engineering). That seems most likely. So maybe in my scenario, it takes 1/4 second, but my scenario is not equivalent to Derek's. That would work fine with Derek's scenario, because the pre-switch state information has already traveled around the wire, and the switch is local, so the _local_ electrons at the source can move/interact as soon as the switch is thrown.
However, that would still throw some doubt on Derek's claim that the field carries _all_ the energy, only proving that it carries at least _some_ energy. And if it carries some energy, it could only have gotten it from the source, thus it carries at least some of the circuit's total transferred energy. That still doesn't mean Derek's claim is wrong, just that it's not entirely proven by his example model.
@@bloodgain I should clarify that the fields do carry all of the energy (as photons), but only from one electron to another. In a conductive wire, free electrons are abundant so the electric field carries energy very short distances (as short as the distance between two atoms). But in the insulator or the air gap between wires, free electrons are scarce so the magnetic field is able to stretch out and transmit energy at great distances. Energy takes both paths from source to sink, but the magnetic field can only carry pulses of energy whereas the electric field can carry a steady current (up to the limit imposed by the resistivity of the wire material; Derek's 1 light-second long loop of wire is far too long to carry DC the full length even with the highest conducting materials we know of).
Thanks for this, Mehdi. I kept showering thinking about this all week and every day I was like, "The electrons have to move to create the fields." I'm glad I'm not a total failure of a physics grad.
This really fixes the misleading aspect of Veritasium's video. I left that video knowing there was something wrong with how he presented the notion that the power only crosses the three meters. Now it all makes perfect sense.
The biggest problem is probably the clickbait title he put in his video. It's going to cause major misinformation for anyone who doesn't watch these follow up videos.
2:51 - "You little... Derek!" Boom, roasted.
I had seen Derek's explanation and thought "wow..this is amazing, i learned a secret of the cosmos". Then a LOT of other video's started to appear from people that where smart and learned, and i watched those as well. I LOVE it. This is science as it should be. Respectful, and always, always let the evidence speak..not the emotion.
love you guys..do not understand everything..i am a simpler man..but i love how you all work with science.
I think it's great that youtube "drama" and "feuds" are being used by the YT science community to get people interested in deep dives into science that they may have never been interested in.
Nice to see linus influence of your background. It was refreshing to see your family and house
This is what science is all about. You're such a man for getting this type of thing going.
SIGN ME UP for scientific debate on youtube. I legitimately think the chain string series should be taught in schools, not for the specific topic, but more for the honest scientific debate and scientific process they used to come to their conclusion.
Mehdi, as an electrical engineer I wholeheartedly thank you, you are pretty much the only goddamn person on the internet who seems to ACTUALLY know about what he's talking about when talking about electricity. I really don't understand why other extremely reputable channels couldn't take this same approach, and I mostly don't understand why electrical-related matters have to ALWAYS be -at least to some extents- mystified and spectacularized as if they were some sort of great big mystery. Electricity is """fairly""" simple, and it would be much much much more simple if people stopped picturing it at some sort of goddamn magical force. Never stop educating the masses Mehdi, NEVER STOP! You really are the only one in the field.
As an electrical engineer, that veritaserium video was kind of infuriating
@@jemert96 I do not agree. Although you (as experts) may not agree with the information, it taught me about poynting vector, which was interesting. Then it got me watching this electroboom video, learning even more on the subject! Although Veritasium should have had a disclaimer at the end saying other effects apply. But really, I'm a chemistry teacher (also physics sometimes) and any lesson I teach is incorrect. There is always another effect that makes the story nog very correct. When I started teaching I was always nuanced. With experience I found that simple is better.
If the vids were correct I wouldn't have watched it, so simple is king here.
I’ve watched several videos concerning this particular “topic”. I’m a novice when it comes to electronics and much of the information is over my head at this point. HOWEVER, it has certainly sparked my curiosity and I feel compelled to LEARN MORE and educated myself. Thanks to ALL of the “RUclipsrs” for helping us to learn more.
This video is great and well done!
I am not a fan of ElectroBoom. But I am a fan of the young Derek M.
What I love about THIS video is how nicely you express the ambivalence of your feelings/understanding. The topic can be seen and described in various ways and you totally acknowledge that. Wonderful.
I realized from this video: Maybe the better question would be: when does the earth formation that the switch is closed reach the light bulb.
Thank you so much for making this. My dad and I were going over Verisatium's video with very similar reactions, and I realized that he's just made a really inefficient capacitor, because for the light bulb to be fullbright immediately, means that causality was broken. I missed the black box amplifier bit, and you made a great point about that too.
It isn't just a capacitor, it's a *distributed* capacitor (and also a distributed inductor). In fact, neither of those alone can give correct answers, and not even a series of lumped components like in Mr Boom's simulation can get it quite right. Transmission lines should really be thought of as their own kind of "thing", somewhat like but also somewhat unlike both capacitors and inductors.
@Cekia Selmi ♋️- Go away already geez!! No one gives a crap!!
@Cekia Selmi ♋️ - Reporting you every single time I see your post!
@@MikeB-Android-Teacher
stop responding to the bots, you are only feeding them by giving them engagement.
Brilliant. Imagine having this guy as a teacher or lecturer. So entertaining and yet miles above my pay grade in education
he would have electrocuted you within a week. when electroboom is at work, stand well back - about 100m is about ok.
he is a teacher, this medium reaches so many more minds than a traditional classroom, and with far less restrictions
I'd say this is a lecture and he is in fact teaching.
I don't understand a word he's saying and I still feel like I know what's going on, how that's possible I don't know.
But he's wrong
Saying electrons are not carrying energy is like saying it's the current that kills not the voltage.
Heh, in fact in that case since electrons don't carry energy, current doesn't kill at all!
@@ElectroBOOM At least that would explain why you're still alive!
It is an abstract concept anyway, and the answer depends on how we define “carrying energy”.
In reality it is a continuous interaction wave between electrons, propagated by the fields between them. So saying that electrons carry the energy is perfectly fine, if we are describing it at a higher level of abstraction.
"It is not the water that carries the energy into a turbine. It is the fluid velocity field!"
It _is_ the current.
Consider a cosmic "ray" that's actually a particle. You get hit by those all the time, and the energy of the particle is ridiculously high. But you don't die.
Now take a hammer and swing it at your head with an absurdly lower amount of energy per particle, and you may very well die.
Same principle as a high voltage and low current due to supply, rather than resistance.
It's trivial to zap yourself harmlessly with over a million volts, with a big enough Van de Graaff generator. It's also trivial to kill yourself with just 120 volts from a wall outlet.
Outstanding analysis
I watched Derek's video the day it was published and had to admit I was lost halfway through. This video finally made me understand what Derek was trying to say, and why you think it's inaccurate. And had to admit your argument made more sense. If we assume there is no resistance, then we must also assume there is no capacitance and inductance, which in turn means there's no electrical and magnetic field. The question then becomes pointless. The resistance in this case cannot be negligible.
No, that's not what he's saying. You can assume no resistance, and in fact Medhi is assuming no resistance anywhere in the wires. Despite the wires not having resistance though, they act as if they do, due to the way that the inductance and capacitance couple together on a long pair of parallel wires. Superconductors exist, but even if you made this circuit with superconductors, the circuit would act as though it had a resistance equal to the characteristic impedance of the line, up until the EM fields have propagated to the short at the far end.
Even with completely superconducting lines, the light will see very little power until the field has had several cycles of propagation around the loop, unless you have the absolute best case scenario where the resistance of the lightbulb is equal to the characteristic impedance and thus you get half power (edit: actually half voltage, not half power) immediately (and you still don't get full power until the propagation delay is complete).
i think, for the first time, i had to comment that i didn't understand a thing
@@clapanse In his video he says "how long will it take for the bulb to light up", not "how long will it take for the bulb to receive full power". The bulb will light up with half power, just not as bright.
@@rdizzy1 it'll likely light up at a tiny fraction of half power. Half is the best possible scenario if the impedance is matched perfectly (actually half voltage, which will give 1/4 power on a resistive load like an incandescent, or likely not much power on a nonlinear load like an LED), but if you figure out the characteristic impedance of the proposed setup and typical lightbulb impedances, the realistic answer is far, far less than half (and likely several reflection cycles before a decent amount of power is transmitted).
@@clapanse Still, I would consider it producing any light whatsoever to be "the bulb is lit".