COMMENTS AND CORRECTIONS: Thanks to Derek at Veritasium for his blessing to make a real-world version of his gedanken experiment. If you haven't seen his video yet, you might want to go watch that for context, and I also highly recommend ElectroBOOM's video on the topic and EEVBlog's video on the topic. Electroboom's video has some simulated scope traces extremely close to what I saw IRL, and a REALLY fantastic animation (8:27) of him waving an electron around in his hand, shedding magnetic fields as it moves (Even though I ignore magnetic fields in this video - I'm trying to think of a test to find out if they matter). Veritasium ruclips.net/video/bHIhgxav9LY/видео.html ElectroBOOM ruclips.net/video/iph500cPK28/видео.html EEVBlog ruclips.net/video/VQsoG45Y_00/видео.html CORRECTIONS TO THIS VIDEO: - The most important thing I believe I ignored in this video is the actual, physical distribution of charge in the switch-side wire while the current is starting up. How much charge travels AT the advancing wavefront and how much charge gets stuck along the wire in between the fuzzball I drew and the battery will depend on the physical size of the wires and how close they are to each other, setting their capacitance. This charge distribution also DOES NOT look the same on both sides of the switch, although I drew it that way for simplicity. In a later experiment (next video) my mind melted a bit as I measured the resistors on both sides of the battery and found the current going through them is different. It doesn't change any of the logic I presented in this video, but it makes some diagrams less than perfect. - It's possible that cross-inductance between the wires contributes to the effect, using almost exactly the same diagram except the wires are connected by a magnetic field rather than an electric field. I couldn't figure out how to decouple these effects day-of, so I'm still thinking on how to test. Hopefully more to come there. - I'm sure there will be loads more - please leave comments about what I screwed up!
Nothing too important, but you used V as the symbol in Ohms law, however V is the unit and U is actually the equation symbol for voltage, just like I is for Amps and R for Ohms, Love your videos, thanks for educating us all
Definitely the best “response” videos of the Veritasium vid yet. I learned a lot and wow, what a wealth of info you are sir. I can’t wait for the next one
Background in physics and materials science (emphasis on semiconductors 😁) All my electronics projects are very hobby-level, but hey, now I own a scope, so maybe I’ll finish that Theremin I tried to build in undergrad and finally satisfy my curiosity for oscillators xD
@@AlphaPhoenixChannel that background is what makes your video on this so much better than everyone else's. This is a situation where the nanoscale mechanics DO matter, and those who don't study semiconductor physics are taught that they almost never matter. Well, that and they aren't ever really taught at all, because the math involved in semiconductor physics is complicated! (and fun; the class I took on them was my favorite in all of my time in college :))
Phenomenal breakdown. I taught high school physics for many years which doesn't mean I'm an expert in physics, but I do feel qualified to evaluate your teaching skills which are through the roof. Can't wait for part 2.
The idea that excites me the most is the idea that he’s just doing what he loves, he has a passion for creating content and he is VERY good at it, imagine if he released some sort of online class.
@@AlphaPhoenixChannel - You know, the largest discoveries usually stems from, "hmh, that's odd...". This question/example had me frustrated as well, but I don't have the equipment to do what you did. Really appreciate both you taking time, and your teaching skills! And to think I thought you were crazy when you made your laser video... Thank you very much, Brian!
Im a studying electrician and big fan of Derek and his channel, however after watching his video I left more confused than when I started. This video answered a lot of the questions that Derek's video raised, thank you. Awesome video
Think this is more of a new to him experiment than actual new science. Which is awesome and not trying to be a Karen, just felt a little misled. Keep on testin bro
I find that with a lot of Veritasium's videos. I can't tell if he deliberately overcomplicates things on purpose in order to create controversy and get views, or if I'm just not educated enough in physics to keep up. With this video in particular I came away very skeptical as well as confused.
@@chad1755 Vertiasium is primarily a content creator, not an educator. I stopped watching his videos because he would prioritise clickbait and spectacle over actual education on concepts. Sometimes he wouldn't even his due diligence and straight up just promote incorrect claims without correction. His video on post-truth is a great example of how without demonstration, he struggles to convey a concept clearly, if at all.
Very good test. It is always great to see what happens in reality! Thanks you. Impedance matching would raise your output voltage. But also in your setup, I would be very worried about the capacitance the probes add between the lines. Remember the stray capacitance between the wires is VERY small, likely much smaller than the capacitance at the probe output. Probes have capacitance to ground and with probes on the switch and load side, you are basically coupling the switch to the load side with extra probe capacitance. I say place probes ONLY on the load side (you still see the steps), make sure your probe is on x10 for smallest capacitance, and maybe use special high frequency probes. Other than that, the only thing that might not have a significant effect is the capacitive coupling through the earth which makes for a slight output voltage difference. Nothing huge though. One more note, knowing your load resistance and the voltage of the first step, you can calculate the line characteristic impedance, and match your load to it, or pick a higher load to see a much larger voltage step at the output. GOOD LUCK with your future tests.
Ah yes all of these words make sense to me. lol. I’m loving that Derek sparked so much enthusiasm for science with that video, even if proved right or wrong, this thought experiment is wonderful to uncover through all of you.
So interested to read this. It also seemed to me that the capacitative coupling was high for two wires a meter apart. The probe capacitance would explain it. Cool.
Best video out there to explain this! A real experiment does so much more than all the hand waving that goes on trying to explain a phenomenon. So good, thank you for this.
Great video! Thanks for doing the experiment for real. I like how you can see the small but constant voltage across the resistor very soon after closing the switch. I was using a 12V battery so if I used your setup I would get .5V across the bulb right away. I have seen that my bulb could light with 2V applied so you’re right it’s not quite there. But I wonder if I tweaked the thickness of the wires or the type of bulb if I could make it work. I’m doing some tests over here (not as impressively long as yours) but I will report back.
I thought about trying to calculate the necessary size/spacing of the wires to impedance match a typical lightbulb, but I’m not convinced that the standard transmission line model applies here, because all of those calculations are assuming you’re pumping the same signal into both wires at once. There’s very particular capacitance and lack of cross inductance that falls out of that. It’s a fun thing to think about. I played with load resistances a bit but I was also fiddling with the source impedance and generally trying to keep everything high enough that the tens of ohms in the wire itself didn’t matter, and get to dc as soon as possible - you can see in these traces it took vaguely 2-3 light speed delays, and some of that was due to only switching on one side of the battery. If you can get a better match itd be pretty cool! Edit: I’d also add that making the spacing a full meter made the effect even weaker, although that didn’t make it into pt.1, so getting it to match is an uphill battle.
This is what you should have done in the first place. I like your videos, but that one was really bad. Instead of making physics accessible to everyone, you made a non existent light bulb, that makes physics look like black magic. With magical light bulb, physics seems like magic. Nothing further from truth. Physics are simple and very understandable when properly explained, like in this video. A real bulb will never light (or if it does, it would explode after 1 us). Also units were wrong in your video. I hope you do a video explaining it correctly.
IMHO absolutely yes. The standard transmission line model can be used; you have _two_ transmission lines, one going to the left and one going to the right. Say the impedance of the particular geometry (wire diameter, wire spacing) is 800 ohms. Now your 'bulb' (resistor) is connected to the battery and the switch by two 800 ohm impedances. Make the load 1600 ohms, and half the battery voltage will appear across the load. Note: the 'standard' transmission line model _ignores_ the speed of light across the gap, and only considers it along the length of the line. So by the standard model the voltage would rise instantly across the load. But of course we know that there is a delay across the width of the line and the rise time would not be instant. IMHO the standard transmission line model is sufficient to describe things at time scales where the the signal will have traveled perhaps 10x the width of the line. Setting up a signal source and scope that can see the shape of the initial rise as well as the step when the reflection comes back from the ends would require a bit more in the way of resources, because now you need a scope with GHz bandwidth. And Derek, I really want to thank you for putting the original video out there. It made me think about something that I already knew in different ways, and deepened my understanding. I've also had lots of fun discussing the various response videos. -Jon
Hi Derek, To get higher voltage, impedance matching would at least bring your voltage up to 6V. Of course even smaller load resistance would raise the voltage even more. But then the large resistance might make it like a very non-realistic lamp. You could bring the wires much closer to increase the capacitance between the lines and so a smaller line impedance that would increase the load voltage, as a proof of concept. But at 1 meter gap, well, I'm afraid there may not be enough juice ...
In four years as a physics student I never took a course as compelling as your 22 minute video. This is the best thing I have seen on RUclips and the first time I've looked for a donation address. Thank you.
EDIT: After looking at this a 2nd time and having a think, I think this test may be fundamentally flawed. You have used x1 oscilloscope probes that have around 100pF tip capacitance across all the nodes. And they are all referenced back to the same point. This means you have about 50pF of capaciance from each side of the load to the positve of the battery. I'm currently working on simulating this and probably doing a video on it, just wanted to point it out now. I think to do this properly you'd have to use a completely isolated scope on the load with the trigger coming from another scope on the switch side via optical fibre. And then you'd have to account for the skew correction in that trigger system as well. It's really tricky to do this right! OLD COMMENT: Awesome work! I'm way too lazy to actually go out and do this!
Yo! I watched a BUNCH of your videos while setting this up, really hoping I wasn’t making some horrible mistake since I hadn’t used a scope in years… thanks!
I was confused by Veritasiums claim that “we’ve always been taught completely wrong about electricity” using the loop of wire example. Like if you make that circuit into a circle instead of a long rectangle you’d get virtually zero instant current (although there would be technically a tiny imperceptible amount) since the whole reason why he can say that there’s any instant current is due to the close proximity of the battery and wires to the bulb. It would’ve generated a lot less controversy if he phrased it differently, and instead of trying to “debunk” regular understanding of electricity, he could’ve just used it as a cool example to explain that wires generate electric fields. I mean it’s not really a revolutionary concept that wires generate a field around them. Yeah, technically me turning my phone on in Canada gives some absolutely tiny amount of current to some other device in China, but I wouldn’t call that current flowing outside of a wire, more of some cool side effects of electromagnetic fields and the inverse square law.
@@camsaffari I thought the illustration of the electrons in the wire was very helpful in explaining why the wire behaves like a capacitor. I have never studied electrical engineering, so electroBOOM's video was a little over my head. I thought this video explained many concepts very well. I'm just happy there's lots of great content: we can get many different takes on Derek's thought experiment and that I've learned more about how electricity works.
Right on. I guess "debunking" gets more clickthroughs than "slight adjustment". It's feels especially odd coming from Derek considering his recent video about honest video titles vs. clickbait titles. (ruclips.net/video/S2xHZPH5Sng/видео.html)
@@runamucker He's just applying that, as well as making ads, to make money. There is nothing odd about it. The only odd thing is sacrificing the education aspect spreading misinformation to get the money goal, which is revolting.
I think @Veritasium is addressing the general public who haven't studied science or engineering a lot. For the trained and self-taught amongst us, that video is kind of a revision of topics from electromagnetic fields, transmission lines etc.
I am working for years now at an institute of high energy physics and have to deal with different frequency signals in PCB design which includes all the effects you have shown in this video (transmission lines, lengthmatching, impedanz, etc.). Consider myself deeply impressed by your practical and complete explanation, Sir. It really made all this "magic" happening on a Circuit Board a little bit more graspable.
Haha wait till you get to gigahertz radio equipment (or anything over 100Mhz)... Now imagine trying to model these way back in the early days of radios.
This video is PHENOMINAL compared to every other explanation I have seen. I absolutely cannot wait until part 2 as alternate configurations of the loop have been bouncing around my head for the last month. (especially the spread out one!)
Wholeheartedly agree with Goodgu - everyone else seems to have completely missed the point. Even the talk of inductance/capacitance seems to miss the point really, but it is good to see the actual effect quantified after so many people relied on it for their whole explanation. The question is ENTIRELY about the whether the energy is carried by the Poynting field, or by the moving electrons.
@@paulwright8695 We already know there are charge effects that will occur over distance and the strength of those effects are inversely proportional to the distance from the charge, in this case the electron. You can mathematically describe what is happening but it doesn't change the reality of how it works. The energy is both In the wire and Outside of the wire. The fact that the electrons are strongly coupled to the conductor and move inside of the conductor (sometime closer to the surface depending on the nature of the current) means that the majority of the energy carried must be proximal to the electron. That is why the conductor's are carrying most of the power, and that is why the Original Video that Veritasium presented is highly misleading because it suggests that (Paraphrase) "it's all about what's happening outside of the wire, not what's happening inside". And that is simply incorrect. I do wish Veritasium had posted his own video walking back his claims when it became quite evident (even by his own words) that the light would not turn "ON" but instead was only dimly lit. (I actually doubt a real light would actually be on by any reasonable stretch of the definition, but I would accept 80% of nominal as on or even many other versions of on. But a slight glow... no) I really appreciate this actual demonstration. Again, you can't run this kind of stuff on a simulator and expect real results until they have been verified by experiment. And I am very very disappointed that Veritasium didn't actually do a REAL Demonstration to prove it when he posted his video or at least say his next video would show proof.
@@paulwright8695 The last sentence doesn't make sense, it are moving electrons that cause the poynting field. Arguing about which one is the actual cause of energy is useless, because they always come together. (And that is why Veritasiums video is just bad science communication)
Man, this test has been done for years in the universities' electronics lab. In fact sending pulses and measuring the bounce is the standard way to detect where a data line is broken. You can measure the distance from the broken point with cm precission in coaxial cables.
These guys should really bring an Electronics Engr on board. Because we understand the imperfections of circuits. I saw one video where the physicist was totally flummoxed by switch bounce. I saw one video where the physicist totally misused the terms voltage and current.
@@QualityRecord Misusing the terms voltage and current is something a backyard mechanic does, not a physicist. Either the physicist forgot the basics, or the physicist was not a physicist. As far as an electrical engineer, I was an EE major in college and we learned how to use those terms the first day. What annoys me as much or worse are those who don't distinguish AC from DC. To mess that up you are not at all qualified to be discussing anything about even the most basic electronics. It's like if someone is discussing their sound system with me and I ask the ohm rating of the speaker and they tell me "300 watts". I know at that point I best say no more.
How? The current running through a wire does not move with the speed of light... Experiments like in this video like to claim as much but basically it has only roughly the speed of light. In reality it is probably around 90% of it or even less. Or do you now the speed of the current for that particular cable?
To further explain it: The coax cable has characteristic mu and epsilon constants, which, in turn, define the propagation velocity of the electromagnetic wave. When the other end of the cable is ended with an impedance load matching the cable's impedance (50 or 75 ohms) there is no reflecting wave. Still, when the cable is broken or shortcut, then you get a reflected wave delayed by the time it takes to travel from the source to the breaking point and back. web.physics.ucsb.edu/~lecturedemonstrations/Composer/Pages/76.18.html.
@@KM-bu5ywthe current doesn't flow at the speed of light, but the electric field that produces the current does. Therefore, you can do this same experiment, measure the time difference between switch on and voltage bounce, divide by c and you got it
Totally! It feels like a very constructive and entertaining application of Cunningham's Law. I love it! It feels like the great debates you hear about between scientific giants in history and it's very exciting!
I feel like, more than anything else, it has shown people that disagreeing is fine. And saying that you disagree with someone is not a personal attack. The world seems to have forgotten that over the past few years.
This reminds me of a true story about an electricity supply company's underground cable division many decades ago. They had an experimental machine in the back of a small truck that could tell them at what distance away their buried power line has a break and where to dig into the ground. They didn't use the machine very often but when they did use it always told them the distance to dig, they dig there, they wouldn't find the break there, then have to dig along either direction expose more cable to find break. After a while they realised the break is always exactly 6 feet away from where the machine says. Then they realised that for all of the years they had been using it they had not been including the length of the hook up cables in between the machine and buried power line.
The machine you are referring to is called a Time Domain Reflectometer (TDR) and is used extensively today. Not accounting for your launch cable is a rookie mistake 😊. The way it works is that electricity will travel at a fraction of the speed of light in a medium depending on the construction (the makeup of the copper conductor) of the cable. The manufacturer of the cable will provide the type of cable that you can then enter into the TDR and “shoot” it to find the distance to the damage, or end of the cable. The signal sent out from the TDR will bounce off the damage and reflect back to the TDR. So if the machine knows the makeup of the cable it can determine the length very precisely.
I think Veritasium could have avoided this whole debate if he'd said "will experience a very tiny but non-zero amount of current" rather than "won't receive the full current" To most people the later suggests a significant fraction of the total current.
He should have explained what would happen if the wires were cut. And how it DOES take one second for the lightbulb to reach full current. His explanation was incredibly lacking.
If he said that the minimal current in the bulb is just a result of wires reacting to changes in the magnetic field (which we observe on a daily basis) his video wouldn't be so "sensational". I consider his video as a complete lie.
@@uuuummm9 That seems really harsh. Explaining things is hard and it always involves some simplification -- it's easy to get it wrong. Fuck, take the standard explanation for GR involving heavy balls on a trampoline. Is that a lie? I mean you aren't really explaining why heavy bodies attract each other in GR because the only reason the bowling ball creates a dent in the trampoline is gravity. If you get into GR the actual explanation only works because it's a warping of space-time and it shifts the forward in time direction partially into the spatial dimensions. So is that a lie? If Veritasium's explanation is than so is it. But I think it's better to regard them both as poor attempts to explain a complex concept.
I'm a high school physics teacher. Students only have a pretty shaky grasp of capacitance and inductance by the end of school. I love that this can be explained referring directly to charge density and forces. No need for transmission lines or antennas. Grade 7 students who know that opposite charges attract and like repel, and waves take time to move could understand this model.
I left the highschool thinking that induced current is basically black magic. We were told that induced current has to exist because of conservation of mangetic flux and that transformators work on the principle of conservation of energy, I was able to solve the problems of this type but I always viewed it induced current as hocus pocus.
@@smrtfasizmu6161 To clarify - what I've described here isn't induction. Induction uses magnetic fields, not electric fields, and is a fair bit more complicated to explain without math... I personally hate explanations that lean on math so if I generally wait until I think of a good analogy before talking about something...
If they are struggling to understand capacitance then I am sorry to say, you are not teaching it right. Let's take the example of a parallel plate capacitor with an air dielectric. It's incredibly easy to explain and the formula describing the capacitance is also incredibly easy and logical. Moving then towards capacitor with a non air dielectric is then one simple step further on. You could even talk about the effective series resistance, though when I was at school level physics they didn't cover that Things become a little bit harder with inductors and magnetic fields, but even the basic equation, Faraday's law is simple enough, and easily demonstrated.
DC electronics theory is hard enough for the novice student. Throwing in capacitance, inductance, and AC electronics principles will seem like black magic until it is learned.
This is definitely the best response to Veritasium I’ve seen. I feel like I really understand it now. It’s great that you gathered O-scope data to show this principle.
Come back in 3 days and you remember barley anything ... but you still feel the „smart“-feeling you’re feeling now. The problem is that the actual knowledge which this feeling was founded on is probably long gone or at least badly fragmented. That’s at least what I observe with myself when I watch “educational” RUclips videos. Yeh they might be informational and highly insightful, but nowhere near comparable with real schooling. I sense that might be part of the reason why today everybody on the internet feels entitled to vent their opinions about subjects they clearly lack real competence on. What are your thoughts on this? Do you observe similar things to happen?
@@petergoestohollywood382 , it depends on the extent to which you are already familiar with subject matter. It's all about how willing you are to fill in the gaps in your knowledge to make what's being shown to you simple. Direct guided teaching is a must in primary education, and mostly necessary in secondary education, but even very young children can teach themselves a lot about things they are genuinely interested in, provided they have good resources, with both information _and_ guidance. This has certainly been true for me for almost all of my life. Of course I can't speak for others, but I feel that were others may not have had similar experiences, it was because they were not encourage to do so, did not have strong interest in any particular subject area, or just did not have access to good resources. The biggest part of _schooling_ is teaching people how to study independently, not simply spoon-feeding them information. As someone with an understanding of physics at a suitable level, the descriptions/explanations given in this video are basically second nature/obvious to me. If you were a 14-year-old student of physics in high school, you'd likely just be starting to get an understanding of things such as the electric field, electric potentials, circuitry etc. at a suitable level to understand what's being discussed here. Having said that, I feel that a young child could quite easily understand what's being said here, if only it's presented in the right way. I have gone back to content that I consumed years ago and which was originally insightful, enlightening, or even just piqued my interest or made me aware of a particular facet of a particular subject, but whose content I perhaps didn't quite fully understand at the time; and now, having since studied that subject facet in greater detail, that content is utterly obvious. To _learn_ is to overcome preconceived notions, and to understand and apply new concepts. Such content may afford you a certain level of understanding (at least if you can overcome any hurdles regarding overwriting preconceived notions), but without also learning how to apply the concepts discussed, the knowledge simply won't stick around for long. That's just how short- and long-term memory work. For example, when I as 7 or 8 years old, my teacher showed me and some other students how to solve simultaneous equations (a system of two linear equations). All of us understood the logic of each step as it was shown to us, but none of us could reproduce the method or answer similar questions unguided, simply because we were not that familiar with the method; but also because we weren't completely used to thinking of things algebraically/abstractly, so re-deriving the steps was not intuitive/obvious. Of course, 4-6 years later, we would all be solving such questions routinely without difficulty, having been exposed to and come to understand algebra in that time.
I really like the electroBOOM one too because he made the excellent point that if "any current" counts as the lightbulb being "on", then the lightbulb would always be on because there's lots of little causes of current constantly in that kind of setup For example, it seems like the wind caused static electricity which caused all kinds of noise in the measurements? And I assume even if everything was isolated very carefully, we'd still be able to see a non-zero current with sensitive enough equipment? I'd be really interested to know how much variation there was in the "background" level of current in this experiment.
Yeah there were pulses of nonzero current all the time but it wasn’t continuous so if I triggered the scope a few times I could see a clean trace. In retrospect a 10k resistor in parallel with the battery probably would have helped that quite a bit (at least for the trigger probe on the yellow trace)
@@AlphaPhoenixChannel Really interesting. So in the original thought experiment where "non zero" counts as "on", the lightbulb would actually be turning "on" randomly (or even just be "on" continuously) even with the switch open all the time.
@@AlphaPhoenixChannel The trace may look clean but as I'm sure you're aware if you had a device sensitive enough it's generally impossible to get absolutely zero current transfer in the real world with, you know, stuff moving around, even cars driving or radio waves floating about (such as how a crystal set radio doesn't need a battery). So by Derek's definition the light globe would always be on no matter the setup in the real world... it's almost as if it was unnecessarily contrived to create a clickbaity video... who'd have thunk it... 😉
@@TristanCunhasprofile It would be on continuously in the real world even if there was no circuit, if it could truly detect non-zero current, just from very slightly charged things about in the near environment. Rubbed your hair and got some static electricity? That's a charge! That'll exert some movement of charge across the lightbulb just by standing near it. Etc etc etc. That's also why Derek's setup is rather contrived, so much so he shot himself in the foot with it.
This sort of back and forth bounce is used to locate damage using timing. Also can show if there isn't anything extra hooked up in to system to steal power, echo will reveal everything
Very interesting. I was always aware that the signal could be analyzed to detect leeching but I never put much thought into what that actually looks like or consists of. Thanks for mentioning it. It stimulates my curiosity in terms of how that analysis takes place and what it looks like.
This ;) I'm a radio amateur and a few years back in our club we made a small device / electronic circuit that make very small but very powerful voltage peaks in a well behaved manner. That with help of an oscilloscope can test the quality of a piece or string (including connectors) of coaxial cable(s) . From the signal on the oscilloscope (top voltage of returning pulses and time from first transmission) you can then interpret if there are any (unexpected) shorts or opens, the dampening effect of the coax, quality of the connectors (if any), impedance mismatches, etc.Very useful in all kind of situations where you're no longer sure if your 'wire' does what it's supposed to do. For example to see if the cable to your antenna is still decent or if it's waterlogged due to the exposure to the elements or broken due to stress at its connector points or any other misfortune that could happen...
Loved the explanation that a millimeter is a very long distance for an electron to move in a wire. I don't think this gets said enough in most explanations of current flow. It shows why electron flow is so slow compared to everything else going on in the circuit. If electrons were astronauts it's the difference between sending someone to the moon vs. going to another star.
It's a lot like ocean waves. The individual drops of water mostly just move up and down. They are just the medium used to transmit the waves. The energy of every wave crashing on the beach has come from a great distance at impressive speed, but the water is mostly the same matter as the previous wave and only slowly cycles in and out.
This was great. I really loved the reverse "dip" of the current flow of the broken wire test after the gradient of EMF field of the primary side begins to turn negative. It makes complete sense that it should occur, but seeing it there on the scope screen was just like the cherry on top of your explanation cake.
I remember 40 years ago, my mentor in my 1st job explaining how electricity ‘flows’ through wires. Your explanation takes that and magnifies it 1000 times! I found it fascinating and loved your explanations. Thank you.
This actually covers the Transmission line theory. At least it does when you cut the wire! The characteric impedance of the wire setup is approximately 45 ohm. If you lower the 2 series resistor to 47 ohm then you can see the 0.2V increase into roughly 2.5V. You can measure this with the oscilliscope near the switch. A 2.5V wave will start from the switch, travel to the open end, bounce back at 5V and return to the switch at 2 times the wire length. I use this theory a lot to remove oscilations on electronic designs. The 1K series resistors causes the current to slowly start up (1.7mA). Changing it in to 47 ohms should make an instant current much more close to the nominal current. Great experiment, very interesting!
Exactly. That initial small step-response of current is revealing the characteristic impedance of the circuit. Since he knows both the wire diameter and spacing, it's simp,e to calculate that value and see how it compares to the 45R you calculated from the scope traces
@@renedekker9806 Yes it does. The characteristic impedance (Z) consists of an impedance L' and a capacitance C' propagating through the wire. It is complex and difficult to calculate, but if you match the series resistance Rs with Z it can be calculated really simply as a resistor division. Imagine 2 long unconnected wires like Brian did when he cut the wire at the end: Only now one wire is connected to the negative pole of the battery and the other connected to the positive pole using a switch and series resistor. As soon as the switch is turned on, there is a division of the series Rs and the Z. When Rs and Z are roughly the same you see a division of 50% , so 2.5V propagating along the wire. At the end of the wire after 1.6usec the 2.5V bounces and reflects to 5V which in turn propagates back to the beginpoint. So behind Rs (at the beginpoint of the wire) you should measure 2.5V for 2 times the propagation time ( 0sec - 3.2usec) and then it will jump to 5V. I must say, my initial 45ohm calculation for the characteric impedance isn't correct. I think it's more close to 5K - 10K, but can't accurately calculate it right now as the series resistance is not matched with the characteristic impedance.
@@liam3284 Yes I think it is. I don't know about the 1/3rd rule though. you should also keep in mind there is a resistor at the beginning and at the end in this setup.
@@foppe6849 -"Imagine 2 long unconnected wires like Brian did when he cut the wire at the end"_ - and now imagine placing the two wires 10km apart. Would the induced voltage still be 2.5V, or would it be less in that case? If it is less in that case, why would it be 2.5V if they are placed 1m apart? Wouldn't the distance between the wires need to be somewhere in the formula to calculate the induced voltage? I would expect it to drop off very quickly with distance. I would expect the 2.5 volt that you mention to only be applicable if the wires are millimeters apart.
I have watched multiple videos trying to debunk or support Veritasium but now, FINALLY a reasonable person puts it's to a practical test. Great video and I can't wait for your next!
Nothing crazy, a luma/brightness keyer can separate darker object from lighter ones (such as fingers in front on white paper) reasonably well to work in this scenario, it's a nice touch.
@@blaster-zy7xx This is called a difference key and works (only with a static camera position) by keying what's different from a reference frame from the same camera; works very well when you have a background as different from the keyed object as the white from his hand there (and the lighting is constant). And it does help the illustration a lot indeed.
It’s a combination of two moving sets of powerwindows for my hands and sleeves, each window contains a chroma key (skin color and black jacket color). A difference matte didn’t work because the table moved when I leaned on it, plus the wires laying on the table occasionally looked like skin or like jacket and had to be manually removed
Electrons can't move at the speed of light because they have mass. Electrons' velocity is called drift velocity and it is directly proportional to the Electric Field applied.
@@surfbyrd1 So you did this experiment when you were 11 or 12 years old? Respect, man. But.... are you sure? Where did you get the equipment and the physics knowledge?
Finally someone explains this in a way I really can follow. That Poynting vector thingy was more confusing than helping. But the simple illustration with the electric field convinced me.
So this is closer to how experiments are actually performed, where the signal is broken down for different phenomena. The Poynting vector is something you talk about after Maxwell's equations and E+M in general. It is hard. Poynting vectors just tell you the flow of energy. I think a quick summary of what Veratasium was talking about comes from the fact that energy in a field is E^2+B^2 and that contains energy. Fields extend like this video shows so a little bit gets to the bulb first which is that early blip. Poynting vectors just ask if we know how the fields, relate, can we tell where the energy goes? They don't representing the physical processes in themselves.
@@nineball039 It's not incorrect either. It's a different point altogether. The experiment Derek picked is a poor fit for demonstrating what he wanted to demonstrate. I don't know that a "good" experiment exists; it's a fairly abstract point that's largely irrelevant in actual practice.
@@danielmorton9956 That's right, people have a really hard time letting go of the idea that energy is this tangible fluid-like "stuff', when really it's something that exists only in our heads because it makes solving problems easier. What's actually out there are electrons and electric/magnetic fields; the Poyting vector is a calculational shortcut that lets you say certain things without having to go through the full calculation.
Current bouncing back and forth causes havoc in electrical fired fireworks unless a firing system has gates built into the circuit. Electric blasting circuits can also have this problem especially when extraneous current is starts to enter the circuit. It's a deep subject that very few truly understand. Maybe you can do a video to prove if a shunted blasting circuit is safer Vs an unshunted one. Again it's a massivly deep bunnyhole of argument.
What? Assuming I'm reading your comment right, are there really people think that a system with the ends floating is as good as one with a terminating resistor? I mean, anyone who's done anything with signaling, including the common DMX lighting protocol (RS485) knows that you **can** often get away without a terminating resistor sometimes, but it is practically required on longer runs.
@@BanterMaestro2-vh5vn Yeah. I'm familiar with them, but wanted to keep things simple. The thing is it's really easy to see the need in real life. RS485 networks, like DMX are a perfect example of how a you can get away with quite a lot without one, but the spec requires it extremely long runs can be unstable otherwise. DMX "works around" the problem by quickly infinitely repeating the messages, but that just means that you will see delays from signal corruption until one manages to get lucky.
After a local accident, they did some off the cuff testing and found that our firework squibs, with ~20' loop of wire twisted off (the way you would carry it) could be ignited just by keying the mic on a Motorola uhf radio next to it. NASA of course has already done much of this type of research because the pyro on spacecraft, and various pyro failures over the years. If i recall, everything is shunted, but they use notably higher currents to ignite the squib (and for good reason considering my first example). They have a publicly available pdf, but can't remember the title. Having done some firework wiring myself years ago I was always surprised just how little it takes to ignite the common squibs, and how far behind fireworks industry is from the research they should be drawing from -- I think the pdf is well over 20 years old!
As a HAM radio operator - I see the experiment as 2 dipole antennas right next to each other and DC as having a short and weak AC impulse signal before reaching a static state. If the two wires weren't connected at the ends and the signal was AC instead, it would be easy to transfer the energy and turn on the light bulb instantly. I've seen this demonstrated in other videos on youtube. Would be interesting to see you bring this point into the debate as well.
With AC you would only transfer current according to the characteristic impedance of the line. With the small wires some foot/meter apart, the characteristic impedance would be close to 1 kOhm. Hence not much power would transfer. (Perhaps if you match the frequency/wavelength to the length of the line, as you do with antennas, you could get some additional benefits?)
Exactly my thoughts. It is practically a very long antenna. With AC at a resonant frequency, you would be able to transfer energy. It would still be a lot less efficient than if you actually connected the ends of the antennas.
It's coupling between the antennas before the DC component is established. Near-field interactions are frickin' weird. Feed it with a 1 kW signal of about 1.5 kHz. Sit back, and wait for the FCC to arrive ;)
As an Electrical Engineer, seeing the effort you put here to explain the phenomenon in this level of detail is extremely fascinating work. Having a lecture is great but seeing it work in reality really makes a statement
just like how every diode is an LED, not in my experience. Most times they just silently die (no more current going through) I ones that actually exploded tough. Never I have seen on shine.
I haven't seen part 2. This is a wonderful start to exploring capacitance and inductance. There is so much more to see if you continue to make variables. Do some reading up on capacitance and inductance. Also, look into the Q factor when power companies have very long runs of high voltage at 60 Hz power transmission. Keep up the good work. Good luck. Don't loose interest.
As an electronics engineering student, THANK YOU! It helps a ton to actually develop an intuitive understanding of what happens, as for all this time the general response I got, even from professors teaching the effects, was the thing I hate the most: "trust the formula, it works!". Phenomenal video, good job!
I hate trusting formulas, which is one of the reasons I didn’t go into deeper physics for my PhD. The amount of solid state physics needed to do semiconductors for the most part can be excellently visualized, which means I can understand it 😁. Gaining intuition from an equation requires a SIGNIFICANT preexistng intuition based on something more tangible, in my experience.
@@AlphaPhoenixChannel That's not what I found in my degree. It's fairly straight forward to look at the formulae and see if it looks right with they key terms oriented in the numerator or denominator of a fraction. Sure, you may not be able to simply create a formula from intuition, (the capacitance formula of a parallel plate capacitor is one I would argue is intuitive) , but they are easy enough to look them up when needed.
I wonder what the graph would look like if it were an actual circle shaped loop of wire rather than the wires running next to each other? Really interesting video! Learned a lot from it to be fair. :)
@@spinnenente Fair enough, I just thought it might stop the interference or something between the wires and maybe be a more accurate result of measuring the speed. I know nothing about physics by the way! Just guessing stuff, but that's how you learn I suppose!
I think the initial blip will have a delay of 2r/c sec. and the steady state will have a delay of πr/c sec. (ignoring ripple). The harder challenge will be to make measurements. Placing of the oscilloscope will matter - at the center of the circle, or near the switch/bulb. Running long wires from the oscilloscope to the probes will also cause additional delay and interference.
Great video. As an RF engineer, I use what you are demonstrating all the time to determine the lengths of lines and discover faults in transmission lines using VNAS and Network Analyzers that use AC signals along with the line's known characteristics. Propagation delay is definitely a factor in coaxial cable, the nature of its construction; it's just a chain of LC circuits.
@@ThreeWhiteSoldiers you wouldn't seethe effects of capacitance and inductance as shown in this video, since they would be acting parallel to the wire, so wouldn't get the shortcut path.
I just love how (not only) this RUclips community and its members react to each other, discussing and adding their own thoughts on the table and so enhancing the viewers' opportunity to learn to just a whole another dimension. And all of that done with all respect to each other. I'd expect this to be a competition field, but instead I hear "go watch that one's video, too" just all the time. It's really inspiring to see this.
I see that as what content creation has always been about, nobody can simply address 7.8 billion people's ability to comprehend any given topic, so why not divide the load, right? That should be where everyone should want to be, as someone who can pass some kind of skill or information on.
@Artificial Hobos Hear hear. Not sure how it's like around there, but a large number of teachers here acquire their teaching qualifications not by their breadth of knowledge of a particular subject, but by passing a teaching exam. I mean, they may have tertiary levels of understanding, but is that truly enough? Are they keeping up with the pace of discovery in other parts of the world? That bothers me to no end.
Very interesting. Initially the 2 wires cross talk "instantly" because they are so close to each other. You made an emitting antenna and a receiving antenna, with few centimetres distance between them. I wonder what would happen if you used coaxial wire or somehow use some shielded wires that cannot cross talk.
that was the whole point of Derek's video - that the energy is around the wire. When you use coax you forbid all of that and then this whole effect goes away and the electricity has to flow the 500 meters before anything happens. He could emulate that by moving the resister 10 meters further away.
I was wondering about the impact of insulation/shielding on the wires as well. But @Idjles Erle addresses that, I think. Yet, something about both Veritasium’s and Phoenix’s videos still “feels” incomplete to me ( I have ZERO electrical engineering or physics education, but have worked extensively in telecom all areas most of my life). So I’ll watch Phoenix’s part 2 to see if/how it addresses that “feeling”. I learn by inferences and logic of these videos - and even if I don’t/can’t do/understand the formulas involved, the practical applications of the facts/concepts presented are intriguing and compelling enough to explore !
Levels of physics seem to go infinitely deep, ask any Quantum physicist. For this experiment, it helps to include the physics that electrons don't literally move through the wire. They PASS their energy to the next electron and so-on down the wire. More like bumping one ball at one one end of a long line of touching balls, and measuring the time the last ball moves. The concept that electrons CARRY energy, and are NOT the actual energy, is usually moot in practical applications, or classes for that matter.
@@genewitch the speed of light is not a limit...in quantum physics it's called instantaneous action at a distance and its faster than the speed of light....it's instantaneous hence the name....
This was absolutely more enlightening than confusing. Thank you! I was struggling to wrap my head around how any current could flow immediately and your explanation was easy for me to follow and cutting the ends demonstrated it perfectly. Cheers for putting in all the effort to turn a thought experiment into a real one!
I have watched a lot of different videos on the Veritasium electricity thought experiment, because I felt he was very misleading. This is definitely the best explanation of the initial small current, I have seen and it clears up a lot of things that Derek left me confused with.
@@BRORIGIN I watch most vids at 2x speed. It is not out of the question. Also the premise of this video is better than the rest, physically testing the phenomenon in question.
This by far and away the best video I have seen on this subject. An honest experiment that, like all good experiments, raises more questions from various effects seen. I have 35 years of civilian service to UK MOD RAF as an avionics specialist; so have a very good feel for this subject. I to have a MICSIG 1104C . It is the most versatile bit of kit I have ever used. Less than half the price if it's Tektronix counterpart. You are very close to a complete description of Transmission Line theory, the fact that it demonstrates the electric field effect so clearly is great. You are also close to another instrument called a TDR; A form of coax cable RADAR. Works on Cat5 and Cat6 as well with a suitable adapter. Nice one very informative
If you buy cables off the shelf instead of making your own transmission line in free space, the cables will list the velocity of propagation with respect to C on the datasheet. The ubiquitous RG-58 will carry a pulse at 66% of C.
Rf engineers and radio hams know all about this and make use of it in antenna designs and stubs which are particularly useful in phase matching or cancelling. The vector voltmeter can be used to make the measurements.
@@ToriKo_ "This all sounds like a different language" That it is. Rather a lot of what you learn in basic electronics has to be revisited. It is still basic electronics but with some unexpected twists. At microwave frequencies, wires just don't work very well and so you use hollow tubes called waveguides and the two polarities will travel inside the tube but on opposite sites *as if* there were two wires, but there isn't. Velocity factor means that the wave isn't actually traveling at the speed of light. The wave triggers the next electrons to start moving, and their moving advances the wave, but the presence of the other wire causes inductance and capacitive effects to slightly retard or delay the advance of the wave. It isn't just wires that do this. Light actually slows down upon entering glass or anything transparent; the degree of slowdown is also known as the refractive index. It is very nearly certain that the photons that pop out the other side of a pane of glass are not the photons that entered. The energy wave travels through the lattice structure and pops off a photon on the other side with the same angle of incidence as on the arriving side; this is how prism and lenses work. Well anyway, it is all very interesting stuff.
17:30 this was my "aha!" Moment. The way you showed the pockets of charge then interacting with electrons on the far side helped so much with what I simply wasn't picking up from Veritassiums video. Fantastic explanation, thank you! Also nice Leatherman
I love when live and real experiments are done to settle a discussion. Everything was as expected, but the part where the current "bounces" back after it reaches a dead end and moves in the opposite direction for a brief period caught me off guard. I never really thought about something like that happening, but it totally makes sense.
@@davidabdollahi7906 No its due to the fact that wires have some inductance and capacitance. So it takes some time to reach RLC steady state until which they resonate.
@@ashwinalagiri-rajan1180 When you use transmission line theory to explain this "bouncing" effect, it is easy to think in terms of waves bouncing back and forth from the end of the wire in much the same way water bounces off objects in a pond. The interference of these waves with each other causes the distinctive "bouncing" current and voltage patterns. They teach us in EE school that RLC circuit behavior is a gross simplification of the behavior of electric circuits that is only valid when the circuit features are much smaller than the signal wavelengths. And we only use RLC equivalents for circuit behavior of real transmission lines at a point. AlphaPheonix's explanation based on charges, electrostatic, magnetostatic and electromagnetic theories are very good explanations and can explain a lot more things that happen in the circuit that are way beyond the ability of RLC circuits to explain.
There is a fantastic old video from AT&T on RUclips about wave behaviour showing how waves reflect (and why you're getting the reflections when you cut the wire). It's well worth a watch to understand how waves work in wires.
Yes, cutting the wires was a great idea. What perhaps he should have said was it was important to cut the wires after having them connected first. You can't start the experiment with them cut, you need them connected at first to get steady state DC voltage drop across the switch before you close it. I've seen lots of other commentary on the original experiment which talk about the ends not being connected without making it clear they have to start off connected for anything to happen when the switch is thrown.
@@romankalinchuk2750 they need to be connected initially or else the switch will have no potential across it. If there's no potential across it when it's closed then nothing will happen, you just end up touching two pieces of metal together (there may be a tiny electrostatic charge transfer). Initially before the wire is cut the switch acts like a capacitor, it's changed up to the full potential of the battery. When the wire is cut that switch ”capacitor” is still charged so when it is closed you will get a sudden rebalance of charge across it. But if you start with it disconnected you essential have an uncharged capacitor, so when you short it nothing happens.
@@andy_taylor Thats not correct. That's not how capacitors work. There is no current flowing though capacitors. Capacitors are not connected internally. The pulse you see comes from the battery, not from the switch and you are completely misunderstanding the video
THANK YOU! Derek's video left such a massive answer-sized hole in my brain, and I needed something more defined filling it. And I only came across this video because I was watching a bunch of your videos because they're super interesting
Thank you, your description of the electrons being constrained by the wires but having a sphere of influence to pull or push ALL electrons around it is what finally made this whole thing click with me.
This was really eye opening. I'm graduating in Electronics Engineering, and seeing actual real life effects of what we are taught is really fascinating.
I made my living off of Transmission Lines for the past several years. This is an excellent description of what's going on. Derek's video was an oversimplification of a very fun topic. I look forward to your follow up videos!
In a power grid, there are so many loads and generators, that it all balances out. If you only had one generator and one big load, the generator acts like a fly wheel storing energy, so all you would really see is a small slow down in the motor.
@@JakeHarris0 was more trying to ascertain the voltage he sees before the main spike in voltage of you’d have ever noticed it before when generator is turned on. Tesla has noted it When he turned on a power station but didnt actually know what it was. Seems you have too many generators power sources running on main lines to notice this or detect it.
I congratulate you on your spectacular and persistent work and explanation! I am a 68-year-old electrical engineer from Hungary who has always been interested in physics.
8:27 If I understand EEVblog's response, that .2 volt bump would be the capacitive coupling. The width distance between the wires matters, as does the actual length of the loop, with regard to the strength of the that bump. That is, different proportions should yield different strengths for that bump. ~~~ Would like to see more control on that width distance. Also, doing the calculations and running simulations, as EEVblog did, ahead of the actual experiment would have formed a more formal hypothesis to compare to the outcome. ~~~ Let's see if someone can kick this up a notch. There's simply more to do.
This was the explanation that made sense to me because as you mention, I couldn't wrap my head around the "magic of the pointing field" as it was dismissing the length of the wire and asserting that the physical distance between the battery and light bulb was all that mattered.
Veritasium deceived his audience by showing the visualizations for a stable state that is only reached after significant time have passed to somehow justify his wrong statement about power getting to the lamp directly at speed of light which is a very different situation. He didn’t show actual visualizations for his “correct” answer.
@@noop9k Yep, ElectroBoom and Dave did videos that explain this at a higher level. Essentially you can think of the wires on each side as transmission wires.
he did say that the lamp has to turn on with ANY current. the problem was that this hypothetical situation can be easily mistaken by people as a very intuitive expectation while it isn't; a light wont turn on with any current, nor having "any" current is "any useful" for other things. he just made a big capacitor. But I suppose the real reason for the video was that energy moves through the electromagnetic field instead of tiny things moving inside of the wire. which is right.
@@falahati > he did say that the lamp has to turn on with ANY current He actually said "the light bulb has to turn on immediately when current passes through it". Maybe because I'm not an engineer, but I thought he was emphasizing the "immediate" part, not saying that any amount of current will turn it on.
@@marko1395 He didn't need to emphasize the any amount of current part in emphasizing the immediate part. Bulbs fade on relative to their load, so if it comes on immediately, it comes on under ANY load
The reason I liked this explanation so much better than Veritassium's is that it showed off both the practical reality, and the interesting technicality at the same time. Derek's video is misleading in the way that it emphasizes a technicality while brushing aside how utterly contrived his setup must be to even achieve that. People leave his video thinking something to be true that isn't. And even then, the 1m distancing itself isn't emphasized enough, viewers will mistakenly attribute most of the phenomenon to light speed rather than proximity and inverse square law. At 10m it's not just that the delay would be 10x as long, it's that it would 1000 times weaker. Saying that the bulb "wouldn't reach it's full power" until the electricity made the loop is like saying an ant helping push an aircraft carrier under full engine power "doesn't quite do all the pushing".
Yep. This is exactly why I didn't like Derek's vid. He's not exactly wrong, but the nuance was thrown out. A lot of the potency will dissipate via wire, because, guess what? In the real world we always have resistance as losses.
@@Chrispheh - Correct. I meant inverse-cube. I think. Or maybe it's invert-square and only 100x, since it's the surface of a sphere at that distance from the origin, not the volume. Hmm.. in any case, at 1 meter it's almost immeasurably small, at 10m, to have a light that could actually pass this test, it would also be triggered by stuff like you blinking your eyes or farting. It's just such a microscopical useless amount of power to even sort of be true... and Derek doesn't even explore this in his video. You're led to believe this would work at any distance between wire pairs and that electricity is not carried by wires. In practical reality, that's rubbish and even in a contrived, imaginary scenario he didn't even make his point very clearly.
Derek's video put me into several hours of thought. I did not think that capacitive coupling could have a measurable effect at that distance, but was very pleased to be shown that I was wrong. Kudos to you for an excellent and well presented explanation of "Derek's Conundrum", as well as the experimental evidence of it's truth.
I suspect a circle with a circumference equal to the same length would produce a similar result except the transient at the beginning would be even smaller, probably immeasurable because the capacitance between the cable lines would be so much smaller. The effect demonstrated here, but with a large circle, wouldn't be testable because the tiny effects would be swamped by other factors, like the distance to the ground and natural electric fields that my be around. You would just see the 1 us to 2 us delay caused by the speed of light restriction. I'd like to see that experiment just to prove my point. You could do a similar thing by shielding the parallel wires.
A circle would mean that the capacitance would have hundreds of meters to travel, rather than a quarter of a meter. I think inverse square law applies, so you'd have like (1000m/pi)=d=318m diameter circle. The difference in capacitance would then be 318^2/0.25^2 or 6,320. Definitely not showing up on an oscilloscope. Remember that static making it hard for him to take readings? Now that static is going to be thousands of times more relatively strong compared to before. Maybe in a large building where the air is still and with a higher voltage and more sensitive equipment you could datect it, but you might also pick up interference from wireless devices.
This might be the single best video I've ever watched on electricity, and it actually allowed me to finally comprehend how electricity carries energy. Thanks!
My hypothesis is that the electricity as mentioned by veritasium generates magnetic fields and electric fields. The magnetic field moving along the wire after you turn on the transistor induce a small current on the other side where the bulb is. So in fact: you immediately get the current as if from a wireless charger, and after the fields travel as far as the wire goes, you get the true 100% of what you want, not including the resistance of course.
This traveling wave is exactly what i was thinking when watching veritasium. Thank you for proving me right. Great explanation. Stuff like this is often overwhelming to the audience. But your way made ot into our brainz.
This video theoretically explains what Derek wanted to show in his video, however you managed to explain it better than Derek, which is an extremely great skill to have
Also Derek explained it in a very very misleading way. He doesn't even mention that the lamp only turns on slightly until a bit later in the video and the way he explains it implies the lamp intensity goes up linearly or smth like that. This video explains it very well without the stuff about the field carrying the energy which while true is not a very practical explanation.
@@markoproloscic4492 Yeah I agree. Derek made it sound like some quantum effects were controlling the wire, but it's a lot less complicated than I thought
@@markoproloscic4492 That's because it's a thought experiment, not a real one. He clearly states, that the imaginary lamp turns on from any current, and that it doesn't receive full current nearly immediately.
@@ognimimerkki It's not wrong inside the design of the experiment, but for the sake of educating people it basically ignores that most people are already familiar with radio transmission. The best way to tech people new ideas is by connecting them to things they already understand and then expanding upon it. Derek tries to imply that some sort of barely understood phenomenon is causing the effect, when it's basically just a broadcasting and receiving antenna.
Thanks... Finally someone that did the experiment. I was so frustrated not seing an experiment at the end of Veritatium video... You cannot tell that everyone (including experts) were wrong all their life without doing a proof experiment, or at least a simulation... It's not like it's a very hard setting in addition. This video was the clearest I saw on this subject.
@@ognimimerkki If it was so clear and it do not claim incredible things, why so many experts got chocked by this video ? Why so many expert claim that the video was wrong and/or missleading ? I'm not saying that the explaination of this video is new, but the Veritatium video was at best missleading, and clearly wrong on some points.
Hi Pierre, in the links provided by Derek at Veritasium, you will see a presentation showing an overlay of theory and measurement as backup proof. I was the one who did the simulation and measurement for Derek. Hope this helps, it's actually a fun measurement. You can turn on the "bulb" much more that what you see here if you match the transmission line impedance to the bulb resistance. Doing that means the voltage on the bulb goes to half of the applied voltage almost instantly, and then jumps up to the full voltage after the propagation time associated with the length of the wire and the speed of light. The resistance of the wire used in this experiment is going to be a factor in the result. I did a scale model that was shorter and used thicker wires so I could neglect resistance.
@@rsa4510 Thank for your response. I do not pretend that the tehory is false, and every video I saw on the subject talk about the impedance matching, including this one. I understand that the idea behind the trought experiment was to show that electromagnetic informations travel at the speed of light in all direction, But the setting was very missleading. Everyone that work some time in electricity or electronic know that all wires are antennas. If you forget to connect a resistor to a disconnected low voltage wire, the current will vary randomly inside. Unless you use a very strong electromagnetic feld, or a filter, you will not be able to command that wire current from outside, because the ambiant noise will be stronger that the command. So, unless you have perfect (and impossible) conditions, you will never be able to light the bulb without additionnal component to create a very strong field and/or a frequency filter and amplifier. The bulb will either: - always be on (if all current turn it on) - flick on and off randomly (if current variations turn it on) - Turn on after the light speed delay (if realistic current count). If you find a way to make a wireless transmetter/receiver that work without the need to create a powerful signal on a precise frequency for the transmitter, and a filter and amplifier for the receiver, you will become rich. Edit: I just understand that the Veritasium video is in fact a commercial for a brand of wireless LEDs. It raise a lot more questions...
Brilliant! Yes it enlightening, precise and cool! And the whole production is watertight! You deserve all your subscribers and more, but more importantly you are doing a super job with sharing the wisdom!
Great to see the experiment done by a true practical Electrical Engineer. well done. what you are amazed with and puzzled you to find the correct answer is actually one of the basis of telecommunication. When you cut the loop you get the little raise still? of course. That's a simple dipole antenna.
Though I am now 70, I truly wish I could have had a Physics Teacher like you in high school to learn from. Keep up the good work. Knowledge is truth and therefore... good.
Michael Schmidt - that is false; knowledge is not truth. Moreover whose knowledge do you know is truth? Aristotle 'knew' that a constant force produced a constant speed. The Catholic church and many other religions 'knew' the earth was the center of the universe. The Chicago Sun Tribune 'knew' Dewey beat Truman. Donald Trump 'knew' he won the 2020 election.
Absolutely amazing! Derek's video got a lot of response videos, and this is by far the best one. Not only it solved the problem, and not only it had done it experimentally, it found other curious things to look at, and instead of just handwaving an explanation for them, you checked them experimentally too. kudos! May this set the bar high for other creators. looking forward for part 2. Thank you
@@noop9k I wouldn’t for a moment say oversimplified. He simplified to a level he was comfortable explaining which was perfectly sufficient. Simplification is, to an absolute, necessary in physics because otherwise you’re looking at a number of things that approach infinity, yet the returns for each newly considered factor becomes infinitesimally important. But yeah, you’re right about the second half. There’s a reason he is the biggest physics channel I guess. He intermixes actually good, informative videos with ragebait/confusion bait. For example, the counter steering video explains a cool and important part of classical mechanics. I forgive the bait videos because it gets people into physics, but it does mean they come away misinformed… not explicitly due to him, it’s just that when you portray something the way he did, it’s very easy to misinterpret if you aren’t already knowledgeable in the field.
Cutting the circuit at one of the far ends was a great way to show that this isn't transmitting the power through the circuit (instead it was a change in the capacitance and resulting change to the EM field the pushed a small current). Another simple way to show it would be to connect each length of wire to the opposite side of the resistor, which should show the smaller current actually going in reverse to what the battery eventually pushes.
Your real experiment on this and explanation was great. Your enthusiasm was infectious and as I began to truly grok what you were saying, my excitement began to rise as well. I'm only beginning my journey in electrical engineering as a hobby and your examples really helped me understand a lot about how electrons move. Thank you for such a great video!
You are absolutely the best person I could have hoped to make a follow up video for this. I don't want some really fancy theoreticals from narcissistic scientists bold enough to oppose a theory but not bold enough to test it. I want someone who is completely neutral and curious like you are to just try, as best as you can, to get something to work, and I'm so glad I now have this video to watch.
My read of the situation is that the academics veritasium consulted expected these results, and that was even BRIEFLY alluded to in veritasiums video. I think Derek himself was just more interested in a flashy title and video so he made a lot of "idealisations" in his argument to make it technically correct but it was ultimately misleading. The worlds power grids already operate on setups similar but much more complicated than this so it's not like these things aren't well understood on a practical level.
You’ve confirmed that it takes a hell of a lot of effort, planning and, yes, expense to light up the very dim bulb of my mind. Thank you for making things a bit clearer.
I really hope Derek answers all these videos. I knew Mehdi would stop his argument in their tracks but his explanation flew above my head. This one was clear enough even for me.
I think the thing that's really weird about this is that Derek isn't *wrong* but he totally overstates the scale of things. There is a noticable volume of electricity, but it's certainly not enough to light any kind of bulb and that kinda messes with the intuition of the situation.
A incandescent light bulb is a poor indicator since it requires time to heat the filament hot enough to emit light. A LED connected directly to the wire would have been a better indicator.
Agree 100%! I was lucky enough to have a science teacher with his energy at my high school way back in 2000. Heaps of his students have him on Facebook so we're still in touch after his retirement! :D
The phenomenon at 19:19 is actually caused by the internal workings of the battery. The electron carriers in the liquid part start out at a higer concentration at the electrode, but that decreases over time until its at a slightly lower equilibrium with diffusion from elsewhere in the liquid
Capacitors are different since you are not waiting for chemical reactions which take femto seconds or less to happen. But what about a battery made out of a super charged 1 Farad capacitor? You dump the capacitor and there is a finite amount of time for it to discharge and let the electrons flow also. There is a formula for that and can be determined.
Loved this, everything about it, the clear explanations, especially how the electrons are not interacting just with the ones next to them, but pretty much with all electrons around them, the closer the stronger the interaction. I'd love to see the experiment with a wire configuration that minimizes the "parasitic" effects, like capacity between the wires; maybe a configuration with the battery and resistor close to each other and the wire placed in a big square with one of the vertices next to the battery and resistor. The long wire can be on one side only, as long as it's the one being attached to the switch. Thank you for doing this!
What happens, then, when you move the battery and “lightbulb” further away from each other so that those initial EM fields don’t start the second wave?
This is what made Derrick's tendentiously chosen geometry so sketchy. He was building more into that arrangement than just a 'circuit', he was building a capacitance/inductance layout without explicitly saying so and then injecting some mumbo-jumbo about magneto-electric fields that supposedly constituted the _real_ electricity. The topology of your arrangement, and Derrick's (and everyone else that following in Derrick's Gedankenexperiment) is invariant, but the placement of the elements in that topology _does_ make a difference.
It's the distance of the switch and the light bulb that matters not the battery and the light bulb, which is yet another misconception induced by Dereks video. And yes you get the first reaction in d/c. Which of course is also weaker the larger d gets.
at the end he is mentioning about the second part he will make and he will try to explore the exact thing you asked. but expect the same small signal but just much less in magnitude. and in fact that small wave is what we unknowingly call psyhic affect on our brains, and partial psyhic abilities are coming from these small fields living beings feel. just do not pay if they say they can read your future; that is not what electric fields do :)
Just came back here because of the new Derek revisit of Electricity in his newest video. Still a clear and concise video and Derek is a beacon of transparency and scientific knowledge. I wish you were as big as him. 💜💙 You deserve 10+ million subs too.
I haven't had physics since high school, but I could follow all of this. You make really complicated physics look relatively easy to understand for non-scientist!
Well it's actually easy...they just want to complicate themselves with numbers and funny interpretation of arithmetic and algebraic expressions...people need to learn physics by doing them
@@mcmerry2846 no, physics is very complicated. it can be simplified so you can understand it which makes complicated subjects easier but in no way are physics simple
@@CyclesAreSingularities it's easy man, but people are just arrogant. Once you learn to learn, you see how easy everything is. Textbook exercises, a ton of text and useless stuff, all those things are just a waste of time.
@@mcmerry2846 all that stuff is essential, quite the opposite of useless. you may know that gravity pulls things back to earth but do you know how to calculate that? do you know that every object on earth experiences 9.8 m/s^2 of acceleration? so 9.8 m/s of speed gets added to your total speed every second of a free fall right? yes, without air (going in detail on this requires a lot of math, which is why it's commonly used in textbook examples). this is simple, now lets make things harder. lets calculate the force of an object hitting something with a certain speed. this seems hard at first but is pretty simple: 9.8 m/s^2 * kg of the object = force in Newton. you need calculus for this, there's no way around it. and it's very useful if you know it. you can measure the force from impact for example in Newton (1kg = 9.8N). however you need to be able to flip around calculations to do this. this you need to practice a lot to let it make sense. if 1N = 1Kg * 1m/s^2 and earth is 9.8m/s^2 then we can simply do this: 1N = ? * 9.8m/s^2 we want to know what the question mark is, so we do this: 1N / 9.8m/s^2 = Kg of mass. this is because if 9.8m/s^2 is multiplied by Kg than dividing by Kg on BOTH sides is possible to remove it from one side and move it to the other in the equation. so simply dividing the impact force with 9.8m/s^2 results in giving you the weight of the object. so there you go, that's how we can calculate somethings weight we can't physically measure. a meteor crashing into earth for example releases energy in the forms of sound, light and heat. which can be measured, the total energy released can be estimated and compared in simulations to see if the results we are getting are accurate. J = 2 / mass * m/s^2 so again we can take J and move it and Mass, then we get: J / M/s^2 = 2 / mass or 2 / J / M/s^2 = mass. so there you go, some crazy applications that are very intresting. all made possible with some simple math, that can get complicated very quickly if you don't master it. this is why you practice them so much, because they need to be second nature in order to tackle complex problems with lots of these calculations coming together. there is almost never a situation in physics that doesn't require math. in fact every subject can be calculated.
COMMENTS AND CORRECTIONS:
Thanks to Derek at Veritasium for his blessing to make a real-world version of his gedanken experiment. If you haven't seen his video yet, you might want to go watch that for context, and I also highly recommend ElectroBOOM's video on the topic and EEVBlog's video on the topic. Electroboom's video has some simulated scope traces extremely close to what I saw IRL, and a REALLY fantastic animation (8:27) of him waving an electron around in his hand, shedding magnetic fields as it moves (Even though I ignore magnetic fields in this video - I'm trying to think of a test to find out if they matter).
Veritasium ruclips.net/video/bHIhgxav9LY/видео.html
ElectroBOOM ruclips.net/video/iph500cPK28/видео.html
EEVBlog ruclips.net/video/VQsoG45Y_00/видео.html
CORRECTIONS TO THIS VIDEO:
- The most important thing I believe I ignored in this video is the actual, physical distribution of charge in the switch-side wire while the current is starting up. How much charge travels AT the advancing wavefront and how much charge gets stuck along the wire in between the fuzzball I drew and the battery will depend on the physical size of the wires and how close they are to each other, setting their capacitance. This charge distribution also DOES NOT look the same on both sides of the switch, although I drew it that way for simplicity. In a later experiment (next video) my mind melted a bit as I measured the resistors on both sides of the battery and found the current going through them is different. It doesn't change any of the logic I presented in this video, but it makes some diagrams less than perfect.
- It's possible that cross-inductance between the wires contributes to the effect, using almost exactly the same diagram except the wires are connected by a magnetic field rather than an electric field. I couldn't figure out how to decouple these effects day-of, so I'm still thinking on how to test. Hopefully more to come there.
- I'm sure there will be loads more - please leave comments about what I screwed up!
Love it. I get popcorn for Veritasium's and Electroboom's responses.
Veritasium blew my mind, and you are piecing it back together again, thank you.
Electrons can totally leave the wire, if it's hot enough :P
d is correct if the switch is near the light bulb because the wires are already charged + and- and then there should be a slight drop and go up again
Nothing too important, but you used V as the symbol in Ohms law, however V is the unit and U is actually the equation symbol for voltage, just like I is for Amps and R for Ohms,
Love your videos, thanks for educating us all
Definitely the best “response” videos of the Veritasium vid yet. I learned a lot and wow, what a wealth of info you are sir. I can’t wait for the next one
Eĺectroboom's answer was very good too , electricians/electronicians i guess
Background in physics and materials science (emphasis on semiconductors 😁)
All my electronics projects are very hobby-level, but hey, now I own a scope, so maybe I’ll finish that Theremin I tried to build in undergrad and finally satisfy my curiosity for oscillators xD
Agreed, thank you
I also agree! Great video, great experiment! Warm greetings from germany :)
@@AlphaPhoenixChannel that background is what makes your video on this so much better than everyone else's. This is a situation where the nanoscale mechanics DO matter, and those who don't study semiconductor physics are taught that they almost never matter. Well, that and they aren't ever really taught at all, because the math involved in semiconductor physics is complicated! (and fun; the class I took on them was my favorite in all of my time in college :))
Phenomenal breakdown. I taught high school physics for many years which doesn't mean I'm an expert in physics, but I do feel qualified to evaluate your teaching skills which are through the roof. Can't wait for part 2.
agreed. i want to see the same exact setup but with a Faraday cage to block the EM field between the battery half and the light bulb half.
The idea that excites me the most is the idea that he’s just doing what he loves, he has a passion for creating content and he is VERY good at it, imagine if he released some sort of online class.
Glad you liked it! It was such a frustrating question I HAD to set it up. I ordered the scope less than 6 hours after watching Derek’s video…
@@AlphaPhoenixChannel - You know, the largest discoveries usually stems from, "hmh, that's odd...". This question/example had me frustrated as well, but I don't have the equipment to do what you did. Really appreciate both you taking time, and your teaching skills!
And to think I thought you were crazy when you made your laser video... Thank you very much, Brian!
Yeah, this guy would make a phenomenal teacher. 🥳
If the resistor is not a light builb, you are just not driving it hard enough.
looool 😅
Everything is a lightbulb with enough current at short enough timeframes.
X'D
Cigarette lighter
Everything's a lightbulb if you're brave enough
Im a studying electrician and big fan of Derek and his channel, however after watching his video I left more confused than when I started. This video answered a lot of the questions that Derek's video raised, thank you. Awesome video
Yup, same here.
Think this is more of a new to him experiment than actual new science. Which is awesome and not trying to be a Karen, just felt a little misled. Keep on testin bro
@@randycorp5333 Where do you get "new science" from?
I find that with a lot of Veritasium's videos. I can't tell if he deliberately overcomplicates things on purpose in order to create controversy and get views, or if I'm just not educated enough in physics to keep up. With this video in particular I came away very skeptical as well as confused.
@@chad1755 Vertiasium is primarily a content creator, not an educator. I stopped watching his videos because he would prioritise clickbait and spectacle over actual education on concepts. Sometimes he wouldn't even his due diligence and straight up just promote incorrect claims without correction. His video on post-truth is a great example of how without demonstration, he struggles to convey a concept clearly, if at all.
Very good test. It is always great to see what happens in reality! Thanks you.
Impedance matching would raise your output voltage. But also in your setup, I would be very worried about the capacitance the probes add between the lines. Remember the stray capacitance between the wires is VERY small, likely much smaller than the capacitance at the probe output. Probes have capacitance to ground and with probes on the switch and load side, you are basically coupling the switch to the load side with extra probe capacitance. I say place probes ONLY on the load side (you still see the steps), make sure your probe is on x10 for smallest capacitance, and maybe use special high frequency probes.
Other than that, the only thing that might not have a significant effect is the capacitive coupling through the earth which makes for a slight output voltage difference. Nothing huge though.
One more note, knowing your load resistance and the voltage of the first step, you can calculate the line characteristic impedance, and match your load to it, or pick a higher load to see a much larger voltage step at the output.
GOOD LUCK with your future tests.
Ah yes all of these words make sense to me. lol. I’m loving that Derek sparked so much enthusiasm for science with that video, even if proved right or wrong, this thought experiment is wonderful to uncover through all of you.
Mehdi, you forgot to mention the step when you get shocked :P
Are you going to make a video on this?
So interested to read this. It also seemed to me that the capacitative coupling was high for two wires a meter apart. The probe capacitance would explain it. Cool.
@@hippopotamus86 He did, a week ago
Best video out there to explain this! A real experiment does so much more than all the hand waving that goes on trying to explain a phenomenon. So good, thank you for this.
Have u seen electroboom's video on this topic ,concise and straight to the point from engineering perspective.
cringe...
passive aggressive cringe
In this era of fake news we don't trust people and theories, we need proof
ActionLab lets gooo
@@GAMEOVER-yy6zj yeah and he goes into more detail too, it was a great video
Great video! Thanks for doing the experiment for real. I like how you can see the small but constant voltage across the resistor very soon after closing the switch. I was using a 12V battery so if I used your setup I would get .5V across the bulb right away. I have seen that my bulb could light with 2V applied so you’re right it’s not quite there. But I wonder if I tweaked the thickness of the wires or the type of bulb if I could make it work. I’m doing some tests over here (not as impressively long as yours) but I will report back.
Nice!
I thought about trying to calculate the necessary size/spacing of the wires to impedance match a typical lightbulb, but I’m not convinced that the standard transmission line model applies here, because all of those calculations are assuming you’re pumping the same signal into both wires at once. There’s very particular capacitance and lack of cross inductance that falls out of that. It’s a fun thing to think about. I played with load resistances a bit but I was also fiddling with the source impedance and generally trying to keep everything high enough that the tens of ohms in the wire itself didn’t matter, and get to dc as soon as possible - you can see in these traces it took vaguely 2-3 light speed delays, and some of that was due to only switching on one side of the battery. If you can get a better match itd be pretty cool!
Edit: I’d also add that making the spacing a full meter made the effect even weaker, although that didn’t make it into pt.1, so getting it to match is an uphill battle.
This is what you should have done in the first place. I like your videos, but that one was really bad. Instead of making physics accessible to everyone, you made a non existent light bulb, that makes physics look like black magic. With magical light bulb, physics seems like magic. Nothing further from truth. Physics are simple and very understandable when properly explained, like in this video. A real bulb will never light (or if it does, it would explode after 1 us). Also units were wrong in your video. I hope you do a video explaining it correctly.
IMHO absolutely yes.
The standard transmission line model can be used; you have _two_ transmission lines, one going to the left and one going to the right. Say the impedance of the particular geometry (wire diameter, wire spacing) is 800 ohms. Now your 'bulb' (resistor) is connected to the battery and the switch by two 800 ohm impedances. Make the load 1600 ohms, and half the battery voltage will appear across the load.
Note: the 'standard' transmission line model _ignores_ the speed of light across the gap, and only considers it along the length of the line. So by the standard model the voltage would rise instantly across the load. But of course we know that there is a delay across the width of the line and the rise time would not be instant. IMHO the standard transmission line model is sufficient to describe things at time scales where the the signal will have traveled perhaps 10x the width of the line.
Setting up a signal source and scope that can see the shape of the initial rise as well as the step when the reflection comes back from the ends would require a bit more in the way of resources, because now you need a scope with GHz bandwidth.
And Derek, I really want to thank you for putting the original video out there. It made me think about something that I already knew in different ways, and deepened my understanding. I've also had lots of fun discussing the various response videos.
-Jon
Hi Derek, To get higher voltage, impedance matching would at least bring your voltage up to 6V. Of course even smaller load resistance would raise the voltage even more. But then the large resistance might make it like a very non-realistic lamp. You could bring the wires much closer to increase the capacitance between the lines and so a smaller line impedance that would increase the load voltage, as a proof of concept. But at 1 meter gap, well, I'm afraid there may not be enough juice ...
This is the way youtube was meant to be used
Lol exactly my thoughts. Lucky us benefiting from these science debates that would’ve otherwise been out of our sights if it weren’t for RUclips
*flat earthers enter the chat* ugh
In four years as a physics student I never took a course as compelling as your 22 minute video. This is the best thing I have seen on RUclips and the first time I've looked for a donation address. Thank you.
EDIT: After looking at this a 2nd time and having a think, I think this test may be fundamentally flawed. You have used x1 oscilloscope probes that have around 100pF tip capacitance across all the nodes. And they are all referenced back to the same point. This means you have about 50pF of capaciance from each side of the load to the positve of the battery.
I'm currently working on simulating this and probably doing a video on it, just wanted to point it out now.
I think to do this properly you'd have to use a completely isolated scope on the load with the trigger coming from another scope on the switch side via optical fibre. And then you'd have to account for the skew correction in that trigger system as well. It's really tricky to do this right!
OLD COMMENT: Awesome work! I'm way too lazy to actually go out and do this!
I am also not rich enough to spend on experiments which doesnt give me bread
@@deva8496
Rich? Lul.
Yo! I watched a BUNCH of your videos while setting this up, really hoping I wasn’t making some horrible mistake since I hadn’t used a scope in years… thanks!
Not many of us have a 1/2 km farm to play with.
@EEVblog
Oh, Dave, please educate us all on probe-work and how to measure using an oscilloscope accurately.
I was confused by Veritasiums claim that “we’ve always been taught completely wrong about electricity” using the loop of wire example. Like if you make that circuit into a circle instead of a long rectangle you’d get virtually zero instant current (although there would be technically a tiny imperceptible amount) since the whole reason why he can say that there’s any instant current is due to the close proximity of the battery and wires to the bulb. It would’ve generated a lot less controversy if he phrased it differently, and instead of trying to “debunk” regular understanding of electricity, he could’ve just used it as a cool example to explain that wires generate electric fields. I mean it’s not really a revolutionary concept that wires generate a field around them. Yeah, technically me turning my phone on in Canada gives some absolutely tiny amount of current to some other device in China, but I wouldn’t call that current flowing outside of a wire, more of some cool side effects of electromagnetic fields and the inverse square law.
Veritasium's video is much more sound that this video. If you want to see the best one watch ElectroBoom's video.
@@camsaffari I thought the illustration of the electrons in the wire was very helpful in explaining why the wire behaves like a capacitor. I have never studied electrical engineering, so electroBOOM's video was a little over my head. I thought this video explained many concepts very well. I'm just happy there's lots of great content: we can get many different takes on Derek's thought experiment and that I've learned more about how electricity works.
Right on. I guess "debunking" gets more clickthroughs than "slight adjustment". It's feels especially odd coming from Derek considering his recent video about honest video titles vs. clickbait titles. (ruclips.net/video/S2xHZPH5Sng/видео.html)
@@runamucker He's just applying that, as well as making ads, to make money. There is nothing odd about it.
The only odd thing is sacrificing the education aspect spreading misinformation to get the money goal, which is revolting.
I think @Veritasium is addressing the general public who haven't studied science or engineering a lot. For the trained and self-taught amongst us, that video is kind of a revision of topics from electromagnetic fields, transmission lines etc.
_This_ is how you settle a physics debate. You do the damn experiment.
Hear, hear! We're not Greek philosophers, we don't just construct arguments... we _test_ things.
Shhhhhh...we're living in a place where half the populaton doesn't believe in science.
seriously, imagine thinking injecting aluminum intravenously is safe and effective for anything @@gplus1000
This was never debated. It's scary to me that a lot of you people can vote.
Like Veritasium/Derek showed with the propeller car (built by a 3rd party) moving faster than the wind powering it.
I am working for years now at an institute of high energy physics and have to deal with different frequency signals in PCB design which includes all the effects you have shown in this video (transmission lines, lengthmatching, impedanz, etc.). Consider myself deeply impressed by your practical and complete explanation, Sir. It really made all this "magic" happening on a Circuit Board a little bit more graspable.
Haha wait till you get to gigahertz radio equipment (or anything over 100Mhz)... Now imagine trying to model these way back in the early days of radios.
This video is PHENOMINAL compared to every other explanation I have seen. I absolutely cannot wait until part 2 as alternate configurations of the loop have been bouncing around my head for the last month. (especially the spread out one!)
Wholeheartedly agree with Goodgu - everyone else seems to have completely missed the point. Even the talk of inductance/capacitance seems to miss the point really, but it is good to see the actual effect quantified after so many people relied on it for their whole explanation. The question is ENTIRELY about the whether the energy is carried by the Poynting field, or by the moving electrons.
totally agree. The oscilloscope cleared it up so much. Especially with the cut wire.
I believe that this plus electroboom's video are the perfect combo
@@paulwright8695 We already know there are charge effects that will occur over distance and the strength of those effects are inversely proportional to the distance from the charge, in this case the electron. You can mathematically describe what is happening but it doesn't change the reality of how it works. The energy is both In the wire and Outside of the wire. The fact that the electrons are strongly coupled to the conductor and move inside of the conductor (sometime closer to the surface depending on the nature of the current) means that the majority of the energy carried must be proximal to the electron. That is why the conductor's are carrying most of the power, and that is why the Original Video that Veritasium presented is highly misleading because it suggests that (Paraphrase) "it's all about what's happening outside of the wire, not what's happening inside". And that is simply incorrect.
I do wish Veritasium had posted his own video walking back his claims when it became quite evident (even by his own words) that the light would not turn "ON" but instead was only dimly lit. (I actually doubt a real light would actually be on by any reasonable stretch of the definition, but I would accept 80% of nominal as on or even many other versions of on. But a slight glow... no)
I really appreciate this actual demonstration.
Again, you can't run this kind of stuff on a simulator and expect real results until they have been verified by experiment.
And I am very very disappointed that Veritasium didn't actually do a REAL Demonstration to prove it when he posted his video or at least say his next video would show proof.
@@paulwright8695 The last sentence doesn't make sense, it are moving electrons that cause the poynting field. Arguing about which one is the actual cause of energy is useless, because they always come together. (And that is why Veritasiums video is just bad science communication)
Ah so that's what an "electric field" looks like, weird my physics teacher didn't mention it's full of grass and a fence
No thats the normal field. If you zoom in far enough you can see tiny Daft Punk concerts on the wires. That's the electric field
And if you’ve ever seen a romance movie where two people run down a field to hug and kiss that’s a magnetic field
pasture for electric sheep?
If you want to be technical, the electric field is everywhere, so you're never really wrong.
I think you'll find he is out standing in his field
Man, this test has been done for years in the universities' electronics lab. In fact sending pulses and measuring the bounce is the standard way to detect where a data line is broken. You can measure the distance from the broken point with cm precission in coaxial cables.
These guys should really bring an Electronics Engr on board. Because we understand the imperfections of circuits. I saw one video where the physicist was totally flummoxed by switch bounce. I saw one video where the physicist totally misused the terms voltage and current.
@@QualityRecord Misusing the terms voltage and current is something a backyard mechanic does, not a physicist. Either the physicist forgot the basics, or the physicist was not a physicist. As far as an electrical engineer, I was an EE major in college and we learned how to use those terms the first day.
What annoys me as much or worse are those who don't distinguish AC from DC. To mess that up you are not at all qualified to be discussing anything about even the most basic electronics. It's like if someone is discussing their sound system with me and I ask the ohm rating of the speaker and they tell me "300 watts". I know at that point I best say no more.
How? The current running through a wire does not move with the speed of light... Experiments like in this video like to claim as much but basically it has only roughly the speed of light. In reality it is probably around 90% of it or even less. Or do you now the speed of the current for that particular cable?
To further explain it: The coax cable has characteristic mu and epsilon constants, which, in turn, define the propagation velocity of the electromagnetic wave. When the other end of the cable is ended with an impedance load matching the cable's impedance (50 or 75 ohms) there is no reflecting wave. Still, when the cable is broken or shortcut, then you get a reflected wave delayed by the time it takes to travel from the source to the breaking point and back. web.physics.ucsb.edu/~lecturedemonstrations/Composer/Pages/76.18.html.
@@KM-bu5ywthe current doesn't flow at the speed of light, but the electric field that produces the current does.
Therefore, you can do this same experiment, measure the time difference between switch on and voltage bounce, divide by c and you got it
I'm enjoying these scientific discussions on RUclips lately. First the mould effect debate and now this. Good stuff, great vid as always.
You're forgetting the using a tailwind to move faster than the tailwind debate :D
Totally! It feels like a very constructive and entertaining application of Cunningham's Law. I love it! It feels like the great debates you hear about between scientific giants in history and it's very exciting!
I feel like, more than anything else, it has shown people that disagreeing is fine. And saying that you disagree with someone is not a personal attack. The world seems to have forgotten that over the past few years.
So is it as fast as light or not? Cause I don't have time to watch 25 minutes for a yes or no answer.
@@johndawd4616 the answer is yesn't
This reminds me of a true story about an electricity supply company's underground cable division many decades ago. They had an experimental machine in the back of a small truck that could tell them at what distance away their buried power line has a break and where to dig into the ground. They didn't use the machine very often but when they did use it always told them the distance to dig, they dig there, they wouldn't find the break there, then have to dig along either direction expose more cable to find break. After a while they realised the break is always exactly 6 feet away from where the machine says. Then they realised that for all of the years they had been using it they had not been including the length of the hook up cables in between the machine and buried power line.
The machine you are referring to is called a Time Domain Reflectometer (TDR) and is used extensively today. Not accounting for your launch cable is a rookie mistake 😊. The way it works is that electricity will travel at a fraction of the speed of light in a medium depending on the construction (the makeup of the copper conductor) of the cable. The manufacturer of the cable will provide the type of cable that you can then enter into the TDR and “shoot” it to find the distance to the damage, or end of the cable. The signal sent out from the TDR will bounce off the damage and reflect back to the TDR. So if the machine knows the makeup of the cable it can determine the length very precisely.
I use to use a TDR on heavy jets. Works great. But few understood how or when to use it.
Time delay reflectometer? TDR
Time delay reflectometer would make more sense, but it is time domain reflectometer. en.m.wikipedia.org/wiki/Time-domain_reflectometer
@@owakulukem Got it. Thanks. “Delay” does make a lot more sense but of it is call Domain, then we will call it domain.
This is BY FAR the best response to this Veritasium video that I've seen. Amazing work Brian, keep it up!
I think Veritasium could have avoided this whole debate if he'd said "will experience a very tiny but non-zero amount of current" rather than "won't receive the full current"
To most people the later suggests a significant fraction of the total current.
He should have explained what would happen if the wires were cut. And how it DOES take one second for the lightbulb to reach full current. His explanation was incredibly lacking.
@@001variation Yes, exactly!
If he said that the minimal current in the bulb is just a result of wires reacting to changes in the magnetic field (which we observe on a daily basis) his video wouldn't be so "sensational". I consider his video as a complete lie.
@@uuuummm9 That seems really harsh. Explaining things is hard and it always involves some simplification -- it's easy to get it wrong.
Fuck, take the standard explanation for GR involving heavy balls on a trampoline. Is that a lie? I mean you aren't really explaining why heavy bodies attract each other in GR because the only reason the bowling ball creates a dent in the trampoline is gravity. If you get into GR the actual explanation only works because it's a warping of space-time and it shifts the forward in time direction partially into the spatial dimensions.
So is that a lie? If Veritasium's explanation is than so is it. But I think it's better to regard them both as poor attempts to explain a complex concept.
The wire literally just acted as an antenna. That's the answer. Literally basics of EE.
I'm a high school physics teacher. Students only have a pretty shaky grasp of capacitance and inductance by the end of school. I love that this can be explained referring directly to charge density and forces. No need for transmission lines or antennas. Grade 7 students who know that opposite charges attract and like repel, and waves take time to move could understand this model.
I left the highschool thinking that induced current is basically black magic. We were told that induced current has to exist because of conservation of mangetic flux and that transformators work on the principle of conservation of energy, I was able to solve the problems of this type but I always viewed it induced current as hocus pocus.
@@smrtfasizmu6161 To clarify - what I've described here isn't induction. Induction uses magnetic fields, not electric fields, and is a fair bit more complicated to explain without math... I personally hate explanations that lean on math so if I generally wait until I think of a good analogy before talking about something...
If they are struggling to understand capacitance then I am sorry to say, you are not teaching it right.
Let's take the example of a parallel plate capacitor with an air dielectric.
It's incredibly easy to explain and the formula describing the capacitance is also incredibly easy and logical.
Moving then towards capacitor with a non air dielectric is then one simple step further on. You could even talk about the effective series resistance, though when I was at school level physics they didn't cover that
Things become a little bit harder with inductors and magnetic fields, but even the basic equation, Faraday's law is simple enough, and easily demonstrated.
DC electronics theory is hard enough for the novice student. Throwing in capacitance, inductance, and AC electronics principles will seem like black magic until it is learned.
This is definitely the best response to Veritasium I’ve seen. I feel like I really understand it now. It’s great that you gathered O-scope data to show this principle.
Come back in 3 days and you remember barley anything ... but you still feel the „smart“-feeling you’re feeling now. The problem is that the actual knowledge which this feeling was founded on is probably long gone or at least badly fragmented.
That’s at least what I observe with myself when I watch “educational” RUclips videos. Yeh they might be informational and highly insightful, but nowhere near comparable with real schooling. I sense that might be part of the reason why today everybody on the internet feels entitled to vent their opinions about subjects they clearly lack real competence on.
What are your thoughts on this? Do you observe similar things to happen?
@@petergoestohollywood382 You are the definition of a Jew lol
Me too!
He's done a fantastic job here!
@@thalanoth What do jews have to do with any of this?
@@petergoestohollywood382 , it depends on the extent to which you are already familiar with subject matter. It's all about how willing you are to fill in the gaps in your knowledge to make what's being shown to you simple. Direct guided teaching is a must in primary education, and mostly necessary in secondary education, but even very young children can teach themselves a lot about things they are genuinely interested in, provided they have good resources, with both information _and_ guidance. This has certainly been true for me for almost all of my life. Of course I can't speak for others, but I feel that were others may not have had similar experiences, it was because they were not encourage to do so, did not have strong interest in any particular subject area, or just did not have access to good resources. The biggest part of _schooling_ is teaching people how to study independently, not simply spoon-feeding them information.
As someone with an understanding of physics at a suitable level, the descriptions/explanations given in this video are basically second nature/obvious to me. If you were a 14-year-old student of physics in high school, you'd likely just be starting to get an understanding of things such as the electric field, electric potentials, circuitry etc. at a suitable level to understand what's being discussed here. Having said that, I feel that a young child could quite easily understand what's being said here, if only it's presented in the right way. I have gone back to content that I consumed years ago and which was originally insightful, enlightening, or even just piqued my interest or made me aware of a particular facet of a particular subject, but whose content I perhaps didn't quite fully understand at the time; and now, having since studied that subject facet in greater detail, that content is utterly obvious. To _learn_ is to overcome preconceived notions, and to understand and apply new concepts. Such content may afford you a certain level of understanding (at least if you can overcome any hurdles regarding overwriting preconceived notions), but without also learning how to apply the concepts discussed, the knowledge simply won't stick around for long. That's just how short- and long-term memory work.
For example, when I as 7 or 8 years old, my teacher showed me and some other students how to solve simultaneous equations (a system of two linear equations). All of us understood the logic of each step as it was shown to us, but none of us could reproduce the method or answer similar questions unguided, simply because we were not that familiar with the method; but also because we weren't completely used to thinking of things algebraically/abstractly, so re-deriving the steps was not intuitive/obvious. Of course, 4-6 years later, we would all be solving such questions routinely without difficulty, having been exposed to and come to understand algebra in that time.
This is by far the best response to Derek's video that I've seen so far, really liked the break-downs of the oscilloscope plot. Top job 👍
I really like the electroBOOM one too because he made the excellent point that if "any current" counts as the lightbulb being "on", then the lightbulb would always be on because there's lots of little causes of current constantly in that kind of setup
For example, it seems like the wind caused static electricity which caused all kinds of noise in the measurements? And I assume even if everything was isolated very carefully, we'd still be able to see a non-zero current with sensitive enough equipment?
I'd be really interested to know how much variation there was in the "background" level of current in this experiment.
Yeah there were pulses of nonzero current all the time but it wasn’t continuous so if I triggered the scope a few times I could see a clean trace. In retrospect a 10k resistor in parallel with the battery probably would have helped that quite a bit (at least for the trigger probe on the yellow trace)
@@AlphaPhoenixChannel Really interesting. So in the original thought experiment where "non zero" counts as "on", the lightbulb would actually be turning "on" randomly (or even just be "on" continuously) even with the switch open all the time.
@@AlphaPhoenixChannel The trace may look clean but as I'm sure you're aware if you had a device sensitive enough it's generally impossible to get absolutely zero current transfer in the real world with, you know, stuff moving around, even cars driving or radio waves floating about (such as how a crystal set radio doesn't need a battery). So by Derek's definition the light globe would always be on no matter the setup in the real world... it's almost as if it was unnecessarily contrived to create a clickbaity video... who'd have thunk it... 😉
@@TristanCunhasprofile It would be on continuously in the real world even if there was no circuit, if it could truly detect non-zero current, just from very slightly charged things about in the near environment. Rubbed your hair and got some static electricity? That's a charge! That'll exert some movement of charge across the lightbulb just by standing near it. Etc etc etc. That's also why Derek's setup is rather contrived, so much so he shot himself in the foot with it.
"I am really excited about this graph right here"
Subscribed.
This sort of back and forth bounce is used to locate damage using timing. Also can show if there isn't anything extra hooked up in to system to steal power, echo will reveal everything
Very interesting. I was always aware that the signal could be analyzed to detect leeching but I never put much thought into what that actually looks like or consists of. Thanks for mentioning it. It stimulates my curiosity in terms of how that analysis takes place and what it looks like.
This ;) I'm a radio amateur and a few years back in our club we made a small device / electronic circuit that make very small but very powerful voltage peaks in a well behaved manner. That with help of an oscilloscope can test the quality of a piece or string (including connectors) of coaxial cable(s) . From the signal on the oscilloscope (top voltage of returning pulses and time from first transmission) you can then interpret if there are any (unexpected) shorts or opens, the dampening effect of the coax, quality of the connectors (if any), impedance mismatches, etc.Very useful in all kind of situations where you're no longer sure if your 'wire' does what it's supposed to do. For example to see if the cable to your antenna is still decent or if it's waterlogged due to the exposure to the elements or broken due to stress at its connector points or any other misfortune that could happen...
Loved the explanation that a millimeter is a very long distance for an electron to move in a wire. I don't think this gets said enough in most explanations of current flow. It shows why electron flow is so slow compared to everything else going on in the circuit. If electrons were astronauts it's the difference between sending someone to the moon vs. going to another star.
It's a lot like ocean waves. The individual drops of water mostly just move up and down. They are just the medium used to transmit the waves. The energy of every wave crashing on the beach has come from a great distance at impressive speed, but the water is mostly the same matter as the previous wave and only slowly cycles in and out.
A simple explanation. ruclips.net/video/Fd2LQVgca7s/видео.html
This was great. I really loved the reverse "dip" of the current flow of the broken wire test after the gradient of EMF field of the primary side begins to turn negative. It makes complete sense that it should occur, but seeing it there on the scope screen was just like the cherry on top of your explanation cake.
Thank you for your clarity in resolution. I appreciate this.
I remember 40 years ago, my mentor in my 1st job explaining how electricity ‘flows’ through wires. Your explanation takes that and magnifies it 1000 times! I found it fascinating and loved your explanations. Thank you.
This actually covers the Transmission line theory. At least it does when you cut the wire! The characteric impedance of the wire setup is approximately 45 ohm. If you lower the 2 series resistor to 47 ohm then you can see the 0.2V increase into roughly 2.5V. You can measure this with the oscilliscope near the switch. A 2.5V wave will start from the switch, travel to the open end, bounce back at 5V and return to the switch at 2 times the wire length. I use this theory a lot to remove oscilations on electronic designs.
The 1K series resistors causes the current to slowly start up (1.7mA). Changing it in to 47 ohms should make an instant current much more close to the nominal current.
Great experiment, very interesting!
Exactly. That initial small step-response of current is revealing the characteristic impedance of the circuit. Since he knows both the wire diameter and spacing, it's simp,e to calculate that value and see how it compares to the 45R you calculated from the scope traces
Shouldn't that voltage also depend on how far the two wires are apart? Why would it 2.5V ?
@@renedekker9806 Yes it does. The characteristic impedance (Z) consists of an impedance L' and a capacitance C' propagating through the wire. It is complex and difficult to calculate, but if you match the series resistance Rs with Z it can be calculated really simply as a resistor division.
Imagine 2 long unconnected wires like Brian did when he cut the wire at the end: Only now one wire is connected to the negative pole of the battery and the other connected to the positive pole using a switch and series resistor. As soon as the switch is turned on, there is a division of the series Rs and the Z. When Rs and Z are roughly the same you see a division of 50% , so 2.5V propagating along the wire. At the end of the wire after 1.6usec the 2.5V bounces and reflects to 5V which in turn propagates back to the beginpoint. So behind Rs (at the beginpoint of the wire) you should measure 2.5V for 2 times the propagation time ( 0sec - 3.2usec) and then it will jump to 5V.
I must say, my initial 45ohm calculation for the characteric impedance isn't correct. I think it's more close to 5K - 10K, but can't accurately calculate it right now as the series resistance is not matched with the characteristic impedance.
@@liam3284 Yes I think it is. I don't know about the 1/3rd rule though. you should also keep in mind there is a resistor at the beginning and at the end in this setup.
@@foppe6849 -"Imagine 2 long unconnected wires like Brian did when he cut the wire at the end"_ - and now imagine placing the two wires 10km apart. Would the induced voltage still be 2.5V, or would it be less in that case?
If it is less in that case, why would it be 2.5V if they are placed 1m apart? Wouldn't the distance between the wires need to be somewhere in the formula to calculate the induced voltage?
I would expect it to drop off very quickly with distance. I would expect the 2.5 volt that you mention to only be applicable if the wires are millimeters apart.
I have watched multiple videos trying to debunk or support Veritasium but now, FINALLY a reasonable person puts it's to a practical test. Great video and I can't wait for your next!
The editing is above and beyond, making some of the overlay graphics go behind real world objects just to ground them into the scene a little better
Nothing crazy, a luma/brightness keyer can separate darker object from lighter ones (such as fingers in front on white paper) reasonably well to work in this scenario, it's a nice touch.
@@lgab Yes BUT he keyed the graphics OVER the real set up. Then his hand passed OVER the graphic.
Woah, I didn't even notice it, that's how natural he made it look. Good observation.
@@blaster-zy7xx This is called a difference key and works (only with a static camera position) by keying what's different from a reference frame from the same camera; works very well when you have a background as different from the keyed object as the white from his hand there (and the lighting is constant). And it does help the illustration a lot indeed.
It’s a combination of two moving sets of powerwindows for my hands and sleeves, each window contains a chroma key (skin color and black jacket color). A difference matte didn’t work because the table moved when I leaned on it, plus the wires laying on the table occasionally looked like skin or like jacket and had to be manually removed
Electrons can't move at the speed of light because they have mass.
Electrons' velocity is called drift velocity and it is directly proportional to the Electric Field applied.
It's called "velocity factor", and radio buffs take it into note while designing antenna systems-co phasing harnesses, for example.
Yep. In open wire, it's about 0.95
Ay was looking for a HAM related comment!
Always good comments to read on good videos! ty :)
Velocifactor?🦖
velocity factor in respect to the speed of light. thus .95 x speed of light.
My brother and I did this experiment in 1966 and learned about delay lines in TV and why physics experiments are so important. Thank you.
Wow how old are you?
@@dorxlab 68
@@surfbyrd1 keep on creating brother never stop
@@surfbyrd1 nice
@@surfbyrd1 So you did this experiment when you were 11 or 12 years old? Respect, man. But.... are you sure? Where did you get the equipment and the physics knowledge?
Finally someone explains this in a way I really can follow. That Poynting vector thingy was more confusing than helping. But the simple illustration with the electric field convinced me.
Simpler for you does not make it correct.
@@nineball039 Ok redditor, but that wasn't the point. Incredibly dumb and unnecessary to interpret it that way.
So this is closer to how experiments are actually performed, where the signal is broken down for different phenomena. The Poynting vector is something you talk about after Maxwell's equations and E+M in general. It is hard. Poynting vectors just tell you the flow of energy. I think a quick summary of what Veratasium was talking about comes from the fact that energy in a field is E^2+B^2 and that contains energy. Fields extend like this video shows so a little bit gets to the bulb first which is that early blip. Poynting vectors just ask if we know how the fields, relate, can we tell where the energy goes? They don't representing the physical processes in themselves.
@@nineball039 It's not incorrect either. It's a different point altogether. The experiment Derek picked is a poor fit for demonstrating what he wanted to demonstrate.
I don't know that a "good" experiment exists; it's a fairly abstract point that's largely irrelevant in actual practice.
@@danielmorton9956 That's right, people have a really hard time letting go of the idea that energy is this tangible fluid-like "stuff', when really it's something that exists only in our heads because it makes solving problems easier. What's actually out there are electrons and electric/magnetic fields; the Poyting vector is a calculational shortcut that lets you say certain things without having to go through the full calculation.
Current bouncing back and forth causes havoc in electrical fired fireworks unless a firing system has gates built into the circuit. Electric blasting circuits can also have this problem especially when extraneous current is starts to enter the circuit. It's a deep subject that very few truly understand. Maybe you can do a video to prove if a shunted blasting circuit is safer Vs an unshunted one. Again it's a massivly deep bunnyhole of argument.
What? Assuming I'm reading your comment right, are there really people think that a system with the ends floating is as good as one with a terminating resistor? I mean, anyone who's done anything with signaling, including the common DMX lighting protocol (RS485) knows that you **can** often get away without a terminating resistor sometimes, but it is practically required on longer runs.
@@BanterMaestro2-vh5vn Yeah. I'm familiar with them, but wanted to keep things simple. The thing is it's really easy to see the need in real life. RS485 networks, like DMX are a perfect example of how a you can get away with quite a lot without one, but the spec requires it extremely long runs can be unstable otherwise. DMX "works around" the problem by quickly infinitely repeating the messages, but that just means that you will see delays from signal corruption until one manages to get lucky.
How bout those detonators timing circuits on a nuclear warhead?
I'm currently trying to fix an HMI ballast, don't give me more stress!!!
After a local accident, they did some off the cuff testing and found that our firework squibs, with ~20' loop of wire twisted off (the way you would carry it) could be ignited just by keying the mic on a Motorola uhf radio next to it. NASA of course has already done much of this type of research because the pyro on spacecraft, and various pyro failures over the years. If i recall, everything is shunted, but they use notably higher currents to ignite the squib (and for good reason considering my first example). They have a publicly available pdf, but can't remember the title. Having done some firework wiring myself years ago I was always surprised just how little it takes to ignite the common squibs, and how far behind fireworks industry is from the research they should be drawing from -- I think the pdf is well over 20 years old!
As a HAM radio operator - I see the experiment as 2 dipole antennas right next to each other and DC as having a short and weak AC impulse signal before reaching a static state. If the two wires weren't connected at the ends and the signal was AC instead, it would be easy to transfer the energy and turn on the light bulb instantly. I've seen this demonstrated in other videos on youtube. Would be interesting to see you bring this point into the debate as well.
And of course, to make the point of the distance and capacitance obvious - it would be cool to see the wire strung out in a big circle.
With AC you would only transfer current according to the characteristic impedance of the line. With the small wires some foot/meter apart, the characteristic impedance would be close to 1 kOhm. Hence not much power would transfer. (Perhaps if you match the frequency/wavelength to the length of the line, as you do with antennas, you could get some additional benefits?)
Exactly my thoughts. It is practically a very long antenna. With AC at a resonant frequency, you would be able to transfer energy. It would still be a lot less efficient than if you actually connected the ends of the antennas.
When I saw Veritasium's setup I thought: ladder line
It's coupling between the antennas before the DC component is established. Near-field interactions are frickin' weird.
Feed it with a 1 kW signal of about 1.5 kHz.
Sit back, and wait for the FCC to arrive ;)
As an Electrical Engineer, seeing the effort you put here to explain the phenomenon in this level of detail is extremely fascinating work. Having a lecture is great but seeing it work in reality really makes a statement
its what Derek should have done instead of pumping some tabloid half-right half-pictured wish washy explanation of this for YT views
Every resistor behaves like a lightbulb if used wrong enough, just like how every diode is an LED, in similar circumstances.
Before those, we had arc lamps, would those be considered spark gaps?
Careful about the diodes, they first are SED, which stands for smoke emitting diode.
@@KrupyFren enough current and the light comes at the same time XD
just like how every diode is an LED, not in my experience. Most times they just silently die (no more current going through) I ones that actually exploded tough. Never I have seen on shine.
Um, afaik every diode really is an led (as well as a solar cell) thou. Some just don't shine in the visible light range.
I haven't seen part 2. This is a wonderful start to exploring capacitance and inductance. There is so much more to see if you continue to make variables. Do some reading up on capacitance and inductance. Also, look into the Q factor when power companies have very long runs of high voltage at 60 Hz power transmission. Keep up the good work. Good luck. Don't loose interest.
As an electronics engineering student, THANK YOU! It helps a ton to actually develop an intuitive understanding of what happens, as for all this time the general response I got, even from professors teaching the effects, was the thing I hate the most: "trust the formula, it works!".
Phenomenal video, good job!
I hate trusting formulas, which is one of the reasons I didn’t go into deeper physics for my PhD. The amount of solid state physics needed to do semiconductors for the most part can be excellently visualized, which means I can understand it 😁. Gaining intuition from an equation requires a SIGNIFICANT preexistng intuition based on something more tangible, in my experience.
@@AlphaPhoenixChannel That's not what I found in my degree. It's fairly straight forward to look at the formulae and see if it looks right with they key terms oriented in the numerator or denominator of a fraction. Sure, you may not be able to simply create a formula from intuition, (the capacitance formula of a parallel plate capacitor is one I would argue is intuitive) , but they are easy enough to look them up when needed.
I wonder what the graph would look like if it were an actual circle shaped loop of wire rather than the wires running next to each other? Really interesting video! Learned a lot from it to be fair. :)
The effect is lessened with distance. Therefore in a circle the distance would always be huge which would probably make the effect unmeasurable.
*boop*
@@spinnenente Fair enough, I just thought it might stop the interference or something between the wires and maybe be a more accurate result of measuring the speed. I know nothing about physics by the way! Just guessing stuff, but that's how you learn I suppose!
@@FriesOfTheDead *boop*
I think the initial blip will have a delay of 2r/c sec. and the steady state will have a delay of πr/c sec. (ignoring ripple).
The harder challenge will be to make measurements. Placing of the oscilloscope will matter - at the center of the circle, or near the switch/bulb. Running long wires from the oscilloscope to the probes will also cause additional delay and interference.
This explanation of electricity makes a lot more sense than anything I've ever seen
Great video. As an RF engineer, I use what you are demonstrating all the time to determine the lengths of lines and discover faults in transmission lines using VNAS and Network Analyzers that use AC signals along with the line's known characteristics. Propagation delay is definitely a factor in coaxial cable, the nature of its construction; it's just a chain of LC circuits.
Ever since Derek's video I thought "what if you cut the ends of the loops?". Good to see someone actually do it.
I had exactly the same thought!
would it matter if the wires were not stretched side to side. but instead, the bulb is on the further side of the battery?
@@ThreeWhiteSoldiers you wouldn't seethe effects of capacitance and inductance as shown in this video, since they would be acting parallel to the wire, so wouldn't get the shortcut path.
Derek says the light bulb still turns on with the wires cut, which is a bit of a stretch.
I just love how (not only) this RUclips community and its members react to each other, discussing and adding their own thoughts on the table and so enhancing the viewers' opportunity to learn to just a whole another dimension. And all of that done with all respect to each other. I'd expect this to be a competition field, but instead I hear "go watch that one's video, too" just all the time. It's really inspiring to see this.
The beauty of science and peer review is debates on facts by proof of hypothesis, and mutual respect is critical to all of it!
@Artificial Hobos I don’t think this is something everybody uses in their life and should know about from elementary.
@@michaelfoxbrass Too bad Fauci don't believe in that shit.
I see that as what content creation has always been about, nobody can simply address 7.8 billion people's ability to comprehend any given topic, so why not divide the load, right?
That should be where everyone should want to be, as someone who can pass some kind of skill or information on.
@Artificial Hobos Hear hear. Not sure how it's like around there, but a large number of teachers here acquire their teaching qualifications not by their breadth of knowledge of a particular subject, but by passing a teaching exam.
I mean, they may have tertiary levels of understanding, but is that truly enough? Are they keeping up with the pace of discovery in other parts of the world? That bothers me to no end.
Very interesting. Initially the 2 wires cross talk "instantly" because they are so close to each other. You made an emitting antenna and a receiving antenna, with few centimetres distance between them. I wonder what would happen if you used coaxial wire or somehow use some shielded wires that cannot cross talk.
that was the whole point of Derek's video - that the energy is around the wire. When you use coax you forbid all of that and then this whole effect goes away and the electricity has to flow the 500 meters before anything happens. He could emulate that by moving the resister 10 meters further away.
@@idjles I dunno, i've sent data wirelessly from TX to Moscow with
I was wondering about the impact of insulation/shielding on the wires as well.
But @Idjles Erle addresses that, I think. Yet, something about both Veritasium’s and Phoenix’s videos still “feels” incomplete to me ( I have ZERO electrical engineering or physics education, but have worked extensively in telecom all areas most of my life).
So I’ll watch Phoenix’s part 2 to see if/how it addresses that “feeling”.
I learn by inferences and logic of these videos - and even if I don’t/can’t do/understand the formulas involved, the practical applications of the facts/concepts presented are intriguing and compelling enough to explore !
Levels of physics seem to go infinitely deep, ask any Quantum physicist. For this experiment, it helps to include the physics that electrons don't literally move through the wire. They PASS their energy to the next electron and so-on down the wire. More like bumping one ball at one one end of a long line of touching balls, and measuring the time the last ball moves. The concept that electrons CARRY energy, and are NOT the actual energy, is usually moot in practical applications, or classes for that matter.
@@genewitch the speed of light is not a limit...in quantum physics it's called instantaneous action at a distance and its faster than the speed of light....it's instantaneous hence the name....
Still convinced we only got this far because someone experienced static shock, and wondered how far it could travel.
This was absolutely more enlightening than confusing. Thank you! I was struggling to wrap my head around how any current could flow immediately and your explanation was easy for me to follow and cutting the ends demonstrated it perfectly. Cheers for putting in all the effort to turn a thought experiment into a real one!
A simple explanation. ruclips.net/video/Fd2LQVgca7s/видео.html
I have watched a lot of different videos on the Veritasium electricity thought experiment, because I felt he was very misleading. This is definitely the best explanation of the initial small current, I have seen and it clears up a lot of things that Derek left me confused with.
Out of all the videos release about this whole topic, this has to be one of the best
Lmao you commented this 12 minutes after the video was posted, you must watch at 2x speed, huh?
I don't necessarily disagree, btw
Agreed, a really good dive into the concepts and excellent to have some practical demonstrations
@@BRORIGIN I watch most vids at 2x speed. It is not out of the question. Also the premise of this video is better than the rest, physically testing the phenomenon in question.
@@BRORIGIN Yeah x2 while I was catching up on my 1000 pushup routine
This by far and away the best video I have seen on this subject. An honest experiment that, like all good experiments, raises more questions from various effects seen.
I have 35 years of civilian service to UK MOD RAF as an avionics specialist; so have a very good feel for this subject.
I to have a MICSIG 1104C . It is the most versatile bit of kit I have ever used. Less than half the price if it's Tektronix counterpart. You are very close to a complete description of Transmission Line theory, the fact that it demonstrates the electric field effect so clearly is great. You are also close to another instrument called a TDR; A form of coax cable RADAR. Works on Cat5 and Cat6 as well with a suitable adapter.
Nice one very informative
If you buy cables off the shelf instead of making your own transmission line in free space, the cables will list the velocity of propagation with respect to C on the datasheet. The ubiquitous RG-58 will carry a pulse at 66% of C.
Also known as the *velocity factor* .
Rf engineers and radio hams know all about this and make use of it in antenna designs and stubs which are particularly useful in phase matching or cancelling.
The vector voltmeter can be used to make the measurements.
Good co-axial cables have a Vp of about 0.8 or more, i.e. 80%
This all sounds like a different language
@@ToriKo_ "This all sounds like a different language"
That it is. Rather a lot of what you learn in basic electronics has to be revisited. It is still basic electronics but with some unexpected twists. At microwave frequencies, wires just don't work very well and so you use hollow tubes called waveguides and the two polarities will travel inside the tube but on opposite sites *as if* there were two wires, but there isn't.
Velocity factor means that the wave isn't actually traveling at the speed of light. The wave triggers the next electrons to start moving, and their moving advances the wave, but the presence of the other wire causes inductance and capacitive effects to slightly retard or delay the advance of the wave.
It isn't just wires that do this. Light actually slows down upon entering glass or anything transparent; the degree of slowdown is also known as the refractive index. It is very nearly certain that the photons that pop out the other side of a pane of glass are not the photons that entered. The energy wave travels through the lattice structure and pops off a photon on the other side with the same angle of incidence as on the arriving side; this is how prism and lenses work. Well anyway, it is all very interesting stuff.
17:30 this was my "aha!" Moment. The way you showed the pockets of charge then interacting with electrons on the far side helped so much with what I simply wasn't picking up from Veritassiums video.
Fantastic explanation, thank you!
Also nice Leatherman
Same! I didnt really understand Veritasium, and Electroboom helped a lot, but that exact moment was like 🤯
Same here!
Awesome part!
These “pockets of charge” are also a gross oversimplification.
@@noop9k isn't everything?
Same with me. I've watched a few different videos addressing it, and this is the first time it all made sense.
I love when live and real experiments are done to settle a discussion. Everything was as expected, but the part where the current "bounces" back after it reaches a dead end and moves in the opposite direction for a brief period caught me off guard. I never really thought about something like that happening, but it totally makes sense.
Like waves hitting a wall, start moving back
@@otherdimensionss there are no walls at the end tips. Simply since there will be more electrons they repel each other backwards
@@davidabdollahi7906 No its due to the fact that wires have some inductance and capacitance. So it takes some time to reach RLC steady state until which they resonate.
@@ashwinalagiri-rajan1180 When you use transmission line theory to explain this "bouncing" effect, it is easy to think in terms of waves bouncing back and forth from the end of the wire in much the same way water bounces off objects in a pond. The interference of these waves with each other causes the distinctive "bouncing" current and voltage patterns.
They teach us in EE school that RLC circuit behavior is a gross simplification of the behavior of electric circuits that is only valid when the circuit features are much smaller than the signal wavelengths. And we only use RLC equivalents for circuit behavior of real transmission lines at a point.
AlphaPheonix's explanation based on charges, electrostatic, magnetostatic and electromagnetic theories are very good explanations and can explain a lot more things that happen in the circuit that are way beyond the ability of RLC circuits to explain.
@@renedosr Alright I think you're more versed in the subject so I accept your answer.
There is a fantastic old video from AT&T on RUclips about wave behaviour showing how waves reflect (and why you're getting the reflections when you cut the wire). It's well worth a watch to understand how waves work in wires.
where is it ?
Cutting the wires was a perfect demonstration of what was happening. I'm incredibly grateful you're changing the distances between the wires as well
I really missed a superimposed image of the open vs closed circuit case.
Yes, cutting the wires was a great idea. What perhaps he should have said was it was important to cut the wires after having them connected first. You can't start the experiment with them cut, you need them connected at first to get steady state DC voltage drop across the switch before you close it. I've seen lots of other commentary on the original experiment which talk about the ends not being connected without making it clear they have to start off connected for anything to happen when the switch is thrown.
@@andy_taylor No you don't need them connected. You misunderstood the video.
@@romankalinchuk2750 they need to be connected initially or else the switch will have no potential across it. If there's no potential across it when it's closed then nothing will happen, you just end up touching two pieces of metal together (there may be a tiny electrostatic charge transfer). Initially before the wire is cut the switch acts like a capacitor, it's changed up to the full potential of the battery. When the wire is cut that switch ”capacitor” is still charged so when it is closed you will get a sudden rebalance of charge across it. But if you start with it disconnected you essential have an uncharged capacitor, so when you short it nothing happens.
@@andy_taylor Thats not correct. That's not how capacitors work. There is no current flowing though capacitors. Capacitors are not connected internally. The pulse you see comes from the battery, not from the switch and you are completely misunderstanding the video
THANK YOU! Derek's video left such a massive answer-sized hole in my brain, and I needed something more defined filling it.
And I only came across this video because I was watching a bunch of your videos because they're super interesting
Thank you, your description of the electrons being constrained by the wires but having a sphere of influence to pull or push ALL electrons around it is what finally made this whole thing click with me.
I watched 8 minutes of this and still didn’t know if there was a delay or not.
This was really eye opening. I'm graduating in Electronics Engineering, and seeing actual real life effects of what we are taught is really fascinating.
I made my living off of Transmission Lines for the past several years. This is an excellent description of what's going on.
Derek's video was an oversimplification of a very fun topic. I look forward to your follow up videos!
So did you notice or have to be aware of a instant voltage in the transmission line when power was turned on many kms away ?
In a power grid, there are so many loads and generators, that it all balances out. If you only had one generator and one big load, the generator acts like a fly wheel storing energy, so all you would really see is a small slow down in the motor.
@@JakeHarris0 was more trying to ascertain the voltage he sees before the main spike in voltage of you’d have ever noticed it before when generator is turned on. Tesla has noted it When he turned on a power station but didnt actually know what it was.
Seems you have too many generators power sources running on main lines to notice this or detect it.
Your awesome for setting up this experiment. I’m an electrician and it’s always fun see the theory we learn in textbooks put to the test. Thanks.
I congratulate you on your spectacular and persistent work and explanation! I am a 68-year-old electrical engineer from Hungary who has always been interested in physics.
8:27 If I understand EEVblog's response, that .2 volt bump would be the capacitive coupling. The width distance between the wires matters, as does the actual length of the loop, with regard to the strength of the that bump. That is, different proportions should yield different strengths for that bump. ~~~ Would like to see more control on that width distance. Also, doing the calculations and running simulations, as EEVblog did, ahead of the actual experiment would have formed a more formal hypothesis to compare to the outcome. ~~~ Let's see if someone can kick this up a notch. There's simply more to do.
This was the explanation that made sense to me because as you mention, I couldn't wrap my head around the "magic of the pointing field" as it was dismissing the length of the wire and asserting that the physical distance between the battery and light bulb was all that mattered.
Veritasium deceived his audience by showing the visualizations for a stable state that is only reached after significant time have passed to somehow justify his wrong statement about power getting to the lamp directly at speed of light which is a very different situation.
He didn’t show actual visualizations for his “correct” answer.
@@noop9k Yep, ElectroBoom and Dave did videos that explain this at a higher level. Essentially you can think of the wires on each side as transmission wires.
he did say that the lamp has to turn on with ANY current. the problem was that this hypothetical situation can be easily mistaken by people as a very intuitive expectation while it isn't; a light wont turn on with any current, nor having "any" current is "any useful" for other things. he just made a big capacitor. But I suppose the real reason for the video was that energy moves through the electromagnetic field instead of tiny things moving inside of the wire. which is right.
@@falahati > he did say that the lamp has to turn on with ANY current
He actually said "the light bulb has to turn on immediately when current passes through it". Maybe because I'm not an engineer, but I thought he was emphasizing the "immediate" part, not saying that any amount of current will turn it on.
@@marko1395 He didn't need to emphasize the any amount of current part in emphasizing the immediate part.
Bulbs fade on relative to their load, so if it comes on immediately, it comes on under ANY load
The reason I liked this explanation so much better than Veritassium's is that it showed off both the practical reality, and the interesting technicality at the same time. Derek's video is misleading in the way that it emphasizes a technicality while brushing aside how utterly contrived his setup must be to even achieve that. People leave his video thinking something to be true that isn't. And even then, the 1m distancing itself isn't emphasized enough, viewers will mistakenly attribute most of the phenomenon to light speed rather than proximity and inverse square law. At 10m it's not just that the delay would be 10x as long, it's that it would 1000 times weaker. Saying that the bulb "wouldn't reach it's full power" until the electricity made the loop is like saying an ant helping push an aircraft carrier under full engine power "doesn't quite do all the pushing".
My friend billy the ant would disagree, he once managed to push start a fire truck right before the driver switched on the ignition.
This... I'm disappointed in Derek in this specific case..
Yep. This is exactly why I didn't like Derek's vid. He's not exactly wrong, but the nuance was thrown out.
A lot of the potency will dissipate via wire, because, guess what? In the real world we always have resistance as losses.
Wouldn't inverse square law mean 10x further corresponds to 100x weaker? You said 1000x weaker.
@@Chrispheh - Correct. I meant inverse-cube. I think. Or maybe it's invert-square and only 100x, since it's the surface of a sphere at that distance from the origin, not the volume. Hmm.. in any case, at 1 meter it's almost immeasurably small, at 10m, to have a light that could actually pass this test, it would also be triggered by stuff like you blinking your eyes or farting. It's just such a microscopical useless amount of power to even sort of be true... and Derek doesn't even explore this in his video. You're led to believe this would work at any distance between wire pairs and that electricity is not carried by wires. In practical reality, that's rubbish and even in a contrived, imaginary scenario he didn't even make his point very clearly.
A resistor is also just a light bulb if you put enough power through it.
Derek's video put me into several hours of thought. I did not think that capacitive coupling could have a measurable effect at that distance, but was very pleased to be shown that I was wrong. Kudos to you for an excellent and well presented explanation of "Derek's Conundrum", as well as the experimental evidence of it's truth.
If you made the loop of wire a circle instead, the delays would be different. You should do the same experiment and see what changes!
I suspect a circle with a circumference equal to the same length would produce a similar result except the transient at the beginning would be even smaller, probably immeasurable because the capacitance between the cable lines would be so much smaller. The effect demonstrated here, but with a large circle, wouldn't be testable because the tiny effects would be swamped by other factors, like the distance to the ground and natural electric fields that my be around. You would just see the 1 us to 2 us delay caused by the speed of light restriction. I'd like to see that experiment just to prove my point.
You could do a similar thing by shielding the parallel wires.
A circle would mean that the capacitance would have hundreds of meters to travel, rather than a quarter of a meter. I think inverse square law applies, so you'd have like (1000m/pi)=d=318m diameter circle. The difference in capacitance would then be 318^2/0.25^2 or 6,320. Definitely not showing up on an oscilloscope. Remember that static making it hard for him to take readings? Now that static is going to be thousands of times more relatively strong compared to before.
Maybe in a large building where the air is still and with a higher voltage and more sensitive equipment you could datect it, but you might also pick up interference from wireless devices.
This might be the single best video I've ever watched on electricity, and it actually allowed me to finally comprehend how electricity carries energy. Thanks!
My hypothesis is that the electricity as mentioned by veritasium generates magnetic fields and electric fields. The magnetic field moving along the wire after you turn on the transistor induce a small current on the other side where the bulb is. So in fact: you immediately get the current as if from a wireless charger, and after the fields travel as far as the wire goes, you get the true 100% of what you want, not including the resistance of course.
This traveling wave is exactly what i was thinking when watching veritasium. Thank you for proving me right.
Great explanation. Stuff like this is often overwhelming to the audience. But your way made ot into our brainz.
This video theoretically explains what Derek wanted to show in his video, however you managed to explain it better than Derek, which is an extremely great skill to have
Also Derek explained it in a very very misleading way. He doesn't even mention that the lamp only turns on slightly until a bit later in the video and the way he explains it implies the lamp intensity goes up linearly or smth like that. This video explains it very well without the stuff about the field carrying the energy which while true is not a very practical explanation.
Derek could have but it would have been less dramatic.
@@markoproloscic4492 Yeah I agree. Derek made it sound like some quantum effects were controlling the wire, but it's a lot less complicated than I thought
@@markoproloscic4492 That's because it's a thought experiment, not a real one. He clearly states, that the imaginary lamp turns on from any current, and that it doesn't receive full current nearly immediately.
@@ognimimerkki It's not wrong inside the design of the experiment, but for the sake of educating people it basically ignores that most people are already familiar with radio transmission. The best way to tech people new ideas is by connecting them to things they already understand and then expanding upon it.
Derek tries to imply that some sort of barely understood phenomenon is causing the effect, when it's basically just a broadcasting and receiving antenna.
Thanks... Finally someone that did the experiment.
I was so frustrated not seing an experiment at the end of Veritatium video... You cannot tell that everyone (including experts) were wrong all their life without doing a proof experiment, or at least a simulation... It's not like it's a very hard setting in addition.
This video was the clearest I saw on this subject.
No expert had any doubt about this, and no such thing was claimed either.
@@ognimimerkki If it was so clear and it do not claim incredible things, why so many experts got chocked by this video ?
Why so many expert claim that the video was wrong and/or missleading ?
I'm not saying that the explaination of this video is new, but the Veritatium video was at best missleading, and clearly wrong on some points.
Hi Pierre, in the links provided by Derek at Veritasium, you will see a presentation showing an overlay of theory and measurement as backup proof. I was the one who did the simulation and measurement for Derek. Hope this helps, it's actually a fun measurement. You can turn on the "bulb" much more that what you see here if you match the transmission line impedance to the bulb resistance. Doing that means the voltage on the bulb goes to half of the applied voltage almost instantly, and then jumps up to the full voltage after the propagation time associated with the length of the wire and the speed of light. The resistance of the wire used in this experiment is going to be a factor in the result. I did a scale model that was shorter and used thicker wires so I could neglect resistance.
@@rsa4510 Thank for your response. I do not pretend that the tehory is false, and every video I saw on the subject talk about the impedance matching, including this one.
I understand that the idea behind the trought experiment was to show that electromagnetic informations travel at the speed of light in all direction, But the setting was very missleading.
Everyone that work some time in electricity or electronic know that all wires are antennas. If you forget to connect a resistor to a disconnected low voltage wire, the current will vary randomly inside.
Unless you use a very strong electromagnetic feld, or a filter, you will not be able to command that wire current from outside, because the ambiant noise will be stronger that the command.
So, unless you have perfect (and impossible) conditions, you will never be able to light the bulb without additionnal component to create a very strong field and/or a frequency filter and amplifier.
The bulb will either:
- always be on (if all current turn it on)
- flick on and off randomly (if current variations turn it on)
- Turn on after the light speed delay (if realistic current count).
If you find a way to make a wireless transmetter/receiver that work without the need to create a powerful signal on a precise frequency for the transmitter, and a filter and amplifier for the receiver, you will become rich.
Edit: I just understand that the Veritasium video is in fact a commercial for a brand of wireless LEDs. It raise a lot more questions...
Brilliant! Yes it enlightening, precise and cool!
And the whole production is watertight! You deserve all your subscribers and more, but more importantly you are doing a super job with sharing the wisdom!
This is the kind of video where I didn't even realize it had been 20 minutes until it was over. Fascinating stuff seeing this all done experimentally!
Super clear explanation without weird simplifications and without diving too deep into the electromagnetic field stuff.
Thanks for the awesome video!
Great to see the experiment done by a true practical Electrical Engineer. well done. what you are amazed with and puzzled you to find the correct answer is actually one of the basis of telecommunication. When you cut the loop you get the little raise still? of course. That's a simple dipole antenna.
Though I am now 70, I truly wish I could have had a Physics Teacher like you in high school to learn from. Keep up the good work. Knowledge is truth and therefore... good.
Michael Schmidt - that is false; knowledge is not truth. Moreover whose knowledge do you know is truth?
Aristotle 'knew' that a constant force produced a constant speed.
The Catholic church and many other religions 'knew' the earth was the center of the universe.
The Chicago Sun Tribune 'knew' Dewey beat Truman.
Donald Trump 'knew' he won the 2020 election.
@@nineball039 Oh, don't be pedantic
@@nineball039 Thinking you know != knowing.
@@isodoublet Knowledge is thinking you know which is not truth either as the OP claims.
@@nineball039 "Knowledge is thinking you know"
No, it isn't.
Absolutely amazing!
Derek's video got a lot of response videos, and this is by far the best one.
Not only it solved the problem, and not only it had done it experimentally, it found other curious things to look at, and instead of just handwaving an explanation for them, you checked them experimentally too. kudos!
May this set the bar high for other creators.
looking forward for part 2.
Thank you
This is such a good video you've managed to explain this concept better then someone with 100 times more subscribers, very well done
And he actually oversimplified the problem a lot. While Derek basically mislead to make people angry, for viral effect.
@@noop9k I wouldn’t for a moment say oversimplified. He simplified to a level he was comfortable explaining which was perfectly sufficient. Simplification is, to an absolute, necessary in physics because otherwise you’re looking at a number of things that approach infinity, yet the returns for each newly considered factor becomes infinitesimally important.
But yeah, you’re right about the second half. There’s a reason he is the biggest physics channel I guess. He intermixes actually good, informative videos with ragebait/confusion bait. For example, the counter steering video explains a cool and important part of classical mechanics. I forgive the bait videos because it gets people into physics, but it does mean they come away misinformed… not explicitly due to him, it’s just that when you portray something the way he did, it’s very easy to misinterpret if you aren’t already knowledgeable in the field.
Cutting the circuit at one of the far ends was a great way to show that this isn't transmitting the power through the circuit (instead it was a change in the capacitance and resulting change to the EM field the pushed a small current).
Another simple way to show it would be to connect each length of wire to the opposite side of the resistor, which should show the smaller current actually going in reverse to what the battery eventually pushes.
Your real experiment on this and explanation was great. Your enthusiasm was infectious and as I began to truly grok what you were saying, my excitement began to rise as well. I'm only beginning my journey in electrical engineering as a hobby and your examples really helped me understand a lot about how electrons move. Thank you for such a great video!
You are absolutely the best person I could have hoped to make a follow up video for this. I don't want some really fancy theoreticals from narcissistic scientists bold enough to oppose a theory but not bold enough to test it. I want someone who is completely neutral and curious like you are to just try, as best as you can, to get something to work, and I'm so glad I now have this video to watch.
My read of the situation is that the academics veritasium consulted expected these results, and that was even BRIEFLY alluded to in veritasiums video. I think Derek himself was just more interested in a flashy title and video so he made a lot of "idealisations" in his argument to make it technically correct but it was ultimately misleading. The worlds power grids already operate on setups similar but much more complicated than this so it's not like these things aren't well understood on a practical level.
You’ve confirmed that it takes a hell of a lot of effort, planning and, yes, expense to light up the very dim bulb of my mind. Thank you for making things a bit clearer.
Because of this video I finally understand how electricity works. Much better explanation than Veritasium or electro-boom did. Amazing video, subbed.
Great to see an actual experiment, and see that it matches what we theoretically predicted. Bravo!
If you want to use a physical switch try using a Mercury wetted Reed relay. I was able to achieve consistent
I really hope Derek answers all these videos. I knew Mehdi would stop his argument in their tracks but his explanation flew above my head. This one was clear enough even for me.
I think the thing that's really weird about this is that Derek isn't *wrong* but he totally overstates the scale of things. There is a noticable volume of electricity, but it's certainly not enough to light any kind of bulb and that kinda messes with the intuition of the situation.
A incandescent light bulb is a poor indicator since it requires time to heat the filament hot enough to emit light. A LED connected directly to the wire would have been a better indicator.
You're a really good teacher. This was explained so well, and your enthusiasm is infectious. I really, really enjoyed the whole video.
Thank you!
Agree 100%!
I was lucky enough to have a science teacher with his energy at my high school way back in 2000. Heaps of his students have him on Facebook so we're still in touch after his retirement! :D
The phenomenon at 19:19 is actually caused by the internal workings of the battery. The electron carriers in the liquid part start out at a higer concentration at the electrode, but that decreases over time until its at a slightly lower equilibrium with diffusion from elsewhere in the liquid
Capacitors are different since you are not waiting for chemical reactions which take femto seconds or less to happen.
But what about a battery made out of a super charged 1 Farad capacitor? You dump the capacitor and there is a finite amount of time for it to discharge and let the electrons flow also. There is a formula for that and can be determined.
Yessss, finally. This was precisely the experiment I was hoping to see. Out clearly shows what's going on. Love it!
Loved this, everything about it, the clear explanations, especially how the electrons are not interacting just with the ones next to them, but pretty much with all electrons around them, the closer the stronger the interaction. I'd love to see the experiment with a wire configuration that minimizes the "parasitic" effects, like capacity between the wires; maybe a configuration with the battery and resistor close to each other and the wire placed in a big square with one of the vertices next to the battery and resistor. The long wire can be on one side only, as long as it's the one being attached to the switch. Thank you for doing this!
What happens, then, when you move the battery and “lightbulb” further away from each other so that those initial EM fields don’t start the second wave?
Reverse square law. You better ask to put them closer.
This is what made Derrick's tendentiously chosen geometry so sketchy. He was building more into that arrangement than just a 'circuit', he was building a capacitance/inductance layout without explicitly saying so and then injecting some mumbo-jumbo about magneto-electric fields that supposedly constituted the _real_ electricity.
The topology of your arrangement, and Derrick's (and everyone else that following in Derrick's Gedankenexperiment) is invariant, but the placement of the elements in that topology _does_ make a difference.
It's the distance of the switch and the light bulb that matters not the battery and the light bulb, which is yet another misconception induced by Dereks video. And yes you get the first reaction in d/c. Which of course is also weaker the larger d gets.
at the end he is mentioning about the second part he will make and he will try to explore the exact thing you asked. but expect the same small signal but just much less in magnitude.
and in fact that small wave is what we unknowingly call psyhic affect on our brains, and partial psyhic abilities are coming from these small fields living beings feel. just do not pay if they say they can read your future; that is not what electric fields do :)
Just came back here because of the new Derek revisit of Electricity in his newest video. Still a clear and concise video and Derek is a beacon of transparency and scientific knowledge.
I wish you were as big as him. 💜💙 You deserve 10+ million subs too.
I haven't had physics since high school, but I could follow all of this. You make really complicated physics look relatively easy to understand for non-scientist!
Facts
Well it's actually easy...they just want to complicate themselves with numbers and funny interpretation of arithmetic and algebraic expressions...people need to learn physics by doing them
@@mcmerry2846 no, physics is very complicated. it can be simplified so you can understand it which makes complicated subjects easier but in no way are physics simple
@@CyclesAreSingularities it's easy man, but people are just arrogant. Once you learn to learn, you see how easy everything is. Textbook exercises, a ton of text and useless stuff, all those things are just a waste of time.
@@mcmerry2846 all that stuff is essential, quite the opposite of useless. you may know that gravity pulls things back to earth but do you know how to calculate that? do you know that every object on earth experiences 9.8 m/s^2 of acceleration? so 9.8 m/s of speed gets added to your total speed every second of a free fall right? yes, without air (going in detail on this requires a lot of math, which is why it's commonly used in textbook examples).
this is simple, now lets make things harder. lets calculate the force of an object hitting something with a certain speed. this seems hard at first but is pretty simple: 9.8 m/s^2 * kg of the object = force in Newton.
you need calculus for this, there's no way around it. and it's very useful if you know it.
you can measure the force from impact for example in Newton (1kg = 9.8N). however you need to be able to flip around calculations to do this. this you need to practice a lot to let it make sense.
if 1N = 1Kg * 1m/s^2 and earth is 9.8m/s^2 then we can simply do this: 1N = ? * 9.8m/s^2 we want to know what the question mark is, so we do this: 1N / 9.8m/s^2 = Kg of mass. this is because if 9.8m/s^2 is multiplied by Kg than dividing by Kg on BOTH sides is possible to remove it from one side and move it to the other in the equation. so simply dividing the impact force with 9.8m/s^2 results in giving you the weight of the object. so there you go, that's how we can calculate somethings weight we can't physically measure.
a meteor crashing into earth for example releases energy in the forms of sound, light and heat. which can be measured, the total energy released can be estimated and compared in simulations to see if the results we are getting are accurate.
J = 2 / mass * m/s^2
so again we can take J and move it and Mass, then we get: J / M/s^2 = 2 / mass or 2 / J / M/s^2 = mass.
so there you go, some crazy applications that are very intresting. all made possible with some simple math, that can get complicated very quickly if you don't master it.
this is why you practice them so much, because they need to be second nature in order to tackle complex problems with lots of these calculations coming together.
there is almost never a situation in physics that doesn't require math. in fact every subject can be calculated.
Such a fantastic response video. This cleared up a lot of stuff that left me confused in Derek's video.