čas přidán 18. 11. 2021
The misconception is that electrons carry potential energy around a complete conducting loop, transferring their energy to the load. This video was sponsored by Caséta by Lutron. Learn more at Lutron.com/veritasium
Further analysis of the large circuit is available here: ve42.co/bigcircuit
Special thanks to Dr Geraint Lewis for bringing up this question in the first place and discussing it with us. Check out his and Dr Chris Ferrie’s new book here: ve42.co/Universe2021
Special thanks to Dr Robert Olsen for his expertise. He quite literally wrote the book on transmission lines, which you can find here: ve42.co/Olsen2018
Special thanks to Dr Richard Abbott for running a real-life experiment to test the model.
Huge thanks to all of the experts we talked to for this video -- Dr Karl Berggren, Dr Bruce Hunt, Dr Paul Stanley, Dr Joe Steinmeyer, Ian Sefton, and Dr David G Vallancourt.
A great video about the Poynting vector by the Science Asylum: • Circuit Energy do...
Sefton, I. M. (2002). Understanding electricity and circuits: What the text books don’t tell you. In Science Teachers’ Workshop. -- ve42.co/Sefton
Feynman, R. P., Leighton, R. B., & Sands, M. (1965). The feynman lectures on physics; vol. Ii, chapter 27. American Journal of Physics, 33(9), 750-752. -- ve42.co/Feynman27
Hunt, B. J. (2005). The Maxwellians. Cornell University Press.
Müller, R. (2012). A semiquantitative treatment of surface charges in DC circuits. American Journal of Physics, 80(9), 782-788. -- ve42.co/Muller2012
Galili, I., & Goihbarg, E. (2005). Energy transfer in electrical circuits: A qualitative account. American journal of physics, 73(2), 141-144. -- ve42.co/Galili2004
Deno, D. W. (1976). Transmission line fields. IEEE Transactions on Power Apparatus and Systems, 95(5), 1600-1611. -- ve42.co/Deno76
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Written by Derek Muller and Petr Lebedev
Animation by Mike Radjabov and Ivy Tello
Filmed by Derek Muller and Emily Zhang
Footage of the sun by Raquel Nuno
Edited by Derek Muller
Additional video supplied by Getty Images
Music from Epidemic Sound
Produced by Derek Muller, Petr Lebedev and Emily Zhang
Komentáře: 76 504
I’m so glad this video exists. I use to completely not even understand how electricity worked, and now I still don’t.
I am still confused, but at a much higher level.
Holy crap. I have degrees in engineering, have investigated numerous electrical fires and worked for decades developing electro-mechanical devices, and no Electrical Engineer has ever explained electricity this way. Things now make a lot more sense.
😢09😮😮😢🎉up🎉 11:35 op 11:36 🎉o😮😮😮🎉l😮😮o😮🎉o🎉🎉😊😮
🎉 11:43 11:43 🎉ol
His explanations are trivial, and answer to light bulb problem is absolutely wrong.
@leonidfro8302 source: "trust me bro"
I studied electronics. I learned about Maxwell and Poynting... And I passed the exam. But I never before brought this (and it has not even been mentioned in all the lessons) into a context with the flow of electricity, specifically with DC. However, having heard about the basic formulas and theorys it became clear very fast ("flash") :-) Thanks for this explanation here...😄
He basically theoretical physcizied our asses. Did a thought experiment and made a prediction
@L Tam what's the prediction
This video should be mandatory curriculum for people trying to obtain Magnetic Particle Testing certificates. This explanation would have made the class so much easier.
When I got mine in the 80's there was NO mention of anything remotely like this. And I did MagPart/NDI on Acft assemblies for years.
Actually it's more of Conductivity Testing which is what this says all about.
@Jon Taylor the explanation of the right hand rule and flow of current, where the field lies is specifically as well as rectification or the capabilities of DC vs AC is what I was referencing. And the theory of electricity helped my understand the why. I’m a very curious person and knowing the how or why helps me out. Maybe not in the field, but certainly for the written testing I took. I understand that this may have not helped everyone, but I had to get my certification online when I inspected Railcars in a repair facility. It was brutal because there was no way to ask questions. The test was literally a regurgitation of information. All memory. I feel like I would have had an easier time because if I didn’t remember the answer, I could have at least understood the theory enough to make a logical assumption. We only ever used Rectified AC with dry particles. Never told why…that was just a standard for our industry/company. Now I’ve got a better idea as to the why Edit: added more
I must add that Magnetic Particle Testing certificates should be a prerequisite to get employment at janitorial jobs.
I just want you to know that through several physics classes and after a decade of angrily not understanding how electrons flowing in a circle actually transmits energy, you have finally answered my question. Hallelujah, thank you for taking the time to actually explain the how instead of simply telling me to memorize equations
i have more questions now
Ima watch it again.
I watched this video a year ago, but I understood nothing because the only thing I learned in high school was that energy moves through the wire. One year later, after learning about electric and magnetic fields and induction, this video made way more sense
bro same. I just passed my master course Advanced Electrodynamics. I even made calculations with Poynting vectors myself. And yet, this video completely blew my mind.
Wow! I’m an old engineer that spent much of my career designing radar systems. While I knew that my first impulsive answer was likely wrong, it’s been a really long time since took a college E&M physics course and first learned about Maxwell’s equations and Poynting vectors. Too, no one explained it nearly as well as you. Thanks.
Well well well, stepping into my territory, eh?! I shall make a video about this!!
Gauntlet thrown! I have my popcorn ready.
من فن شمام😂😂😂 فارسیم نوشتم چون میدونم ایرانی هستین
I would love to see your take on this
This is really cool. I always thought of it as water because that's what helped me pass a circuts class in college, but I've always been curious about magnetic fields and stuff, so this answer is cooler and therefore better.
Magnets; how do they work? I love that question is treated as idiotic but it’s actually a profoundly good and important and in fact difficult question lol.
@Rick MacDonald You can only explain something in terms of something else which is bound to be true, axioms (set of things which are accepted as truth). In order to explain why a rubber band contracts, we explain it in terms of electrostatic attraction. In order to explain electrostatic attraction, you must know something more fundamental than electrostatic attraction in order to explain it. I hope you can see how this is a problem, there NEEDS to be something fundamental in order to explain ANYTHING. Electromagnetism just turns out to be THAT fundamental thing, you could go a little bit deeper if you know about theoretical physics but you still have to accept something as a fundamental truth of the universe in order to explain other things. (I heard this from Richard Feynman) If my answer to this question is incorrect, please let me know :)
So in theory, if we could use a box or device to block the magnetic and electrical fields the load wouldn’t work, in this case light wouldn’t turn on? Could we get a follow up video showing that? Also would be interesting to use iron fillings to show your theory in a working circuit. I’m an electrician and was never taught this thought process! This is why I love this field, always learning. Great video, keep up the great work.
The iron fillings distort the actual fields because they to give off a magnetic field themselves so the representation would not be correct. Yes of the fields were some how blocked zero would happen. Here's the thing though, the Eather permeates everything because it is 1,000 times smaller then the smallest atom.
@marathonman so does this have something to do with Eather Theory cause it does remind me of it.
Yes, would be interesting to put up some sort of physical barrier at 90 degrees to the wire and see what happens...
Great experimental thinking here. I believe you'll find that they are inseperable however. This video is somewhat misinformative. In transmitting energy, wires do indeed guide the transmission of power (that's why we use them) what they don't do is (fully) CONFINE it.
@daviga1 "Never try to teach a pig to sing, it only frustrates you, and annoys the pig"(Isaac Asimov)
Thank you for the video and challenging the every day assumptions. I appreciate this 🎉. A couple of questions: Where and how did you prove that it takes 1/c? If you have done testing, where can I read more about the details of your test? How do we explain the impedance that happens in large conductors along with skin effect in AC, and the transient behavior in DC switching?
OMG, I am a poor student in science but exactly 2 days ago I was wondering how electricity travels in the wire, does it do like water through the pipe to be tapped by a switch. Your explanation is awesome. Now I am 65 and this knowledge may help me to understand Physics in a better way in my next Birth. Hats off to you Sir.
If you stay healthy you still have a long life
@Hello World Thank you Dear, Mercy. Chari
After watching this video I can confidently say I understand less about how electricity works than I did before.
Try opening your mind sometime ?
Yes, same for me. It is a new concept for me, so I am so glad about the video but unfortunatelly many questions raised that are not covered by the video...
Because it does touch on a more fundamental 'weirdness' (not really) about the universe that you didn't know about before.
@Alan Wannemaker But what if the information in this presentation is in error? How does that profit an individual to spend a lot of time and mental energy trying to understand something that may not be true. It may be like global warming, all garbage but we still won't quit talking about it.
Because he's lying. He's using misleading editing with the professors to try to make it sound like he's saying something counterintuitive. He's cheating the viewer.
I'm a student preparing for neet exam and my teacher had discussed this in Allen classroom lectures.... PG sir ☺️....
This is absolutely sensible and it can easily be understood when when you look at while a lot of PCB fails today, Rick Hartley and Dan beeker already gave something about this. It's all about the space, energy travels in space not the wire, but follow the part of least impedance the wire only serve as a wave guide.
It’s refreshing to see somebody that is open to friendly debate. I can understand scientists being competitive but they never killed one another.
An explanation why most electrical devices only work with DC current would be interesting now! Probably because a lot of components have some kind of diodes built into them and therefore no electromagnetic fields can build up when the current vector points in the “wrong direction“…🤔
I've watched this video several times trying to wrap my brain around it. If this hypothesis is true, then , using your setup with the light bulb, you should be able to disrupt the flow of energy from battery to bulb by placing a large magnetic field/shield between the battery and bulb.
I feel like a baby who just realized mom and dad don’t really disappear during peek-a-boo
It's light, Joe, but not as you know it! (Or thought you knew it)
okay but they still can't see me behind the ankle-high curtains
I think, what actually matters, is the location of the switch. Think if you put the switch in the middle which is 0.75 * 10^8 meters away from battery and the light bulb, when you close the switch, you'll create a signal and it shall travel from the switch to the light bulb. Thus the bulb won't light up, until the signal reach the bulb which is at least 1/4s.
I would highly recommend “story of electricity” by Jim Al-Khalili to understand the whole concept of electricity, how it was first discovered and how over time countless other technologies were developed by the discovery of electricity
Well explained. Electricity is basically a mix of electron flow and magnetism that energizes the conductors.
Those Maxwell equations mantioned at the beginning are actually vectorised reductions of his 12 original equations. The work was done by Heaviside mentioned later on. Interesting that it's fields that are claimed to carry the energy. Lorentz's special relaativity which came 4 years before Einstein's and passes all the same tests was rejected because he postulated an ether, which in my opinon is in fact a field and of course everyone accepts the Higgs field nowadays. Really once you drill down it bcomes clear that a large amound of what we are told is in fact wrong! Great video BTW.
This video literally changed 3 times and I have watched every time it gets better 👍
The fundamental law of physics: electricity disappear if you stop paying bills.
No its the laws of capitalism that govern the energy flow
Nikola Tesla said energy can be free , but are we willing to
No You can create electricity if you want Many still it to :)
Unless you own a solar panel
There’s Immense Happiness watching this video ,knowing how universe actually works and understanding every bit of it Answering those baffling questions Thanks a ton @ veriritasium
I am not so good in physics so I have a question... So if we will remove isolation from a wire and put something iron on it (or even just near it) - this iron thing will magnetize after some time? But what I definitely learned thanks to that video is that if we put a lamp near a wire, it may light after a while. Actually, I've learned it experimentally before, but now I really understand why it happened!
putting it nnear the wire will just turn it to power grid situation being air the bad conductor
Interesting, but the wires would already have fields propagated through them, because one end is connected to the battery (i.e. capacitance). What happens if you adjust the experiment, and use two switches, on each pole of the battery, closed simultaneously? Does it change anything?
Probably not. The electrons dont care where the switch is, it only cares where electrons are flowing
you are a genius for the way you teach us this. Thank you, I have learnt so much from this channel. Everyone who watches this please pay attention, this is very intelligent information.
Wow…this is going to take a while to get my head around. I’m not an electrician but I did take a practical electronics course in grade school. At that time they used the water comparison.
This really shakes up my own personal understanding of electricity and how it works. I think that electricity is a triad of functioning flows of which at its core importance is the potential difference in electrons. What is an electron. The difference is life and death. Light and darkness. Hot and cold.
Of course I find this video now… around 6 months ago I got into a small debate with my electrical engineering professor over a topic very similar to this. Everyone in the class seemed to be on the professors side which I guess makes sense but then the following week our professor walks into class and tells me he thought about what I was asking and had looked into it. He walked up to the board and showed some of the similar stuff you did in this video and proclaimed I had actually been correct and my original question that countered his previous discussion he admitted to the class he was in fact wrong. This was the first time in my life I had such a crystallized idea of what someone that was truly intelligent acted like. He wasn’t upset, frustrated or hurt that his initial statement was wrong because he didn’t care about being right, he cared about the truth. I know it sounds corny to say seeing someone look for confirmation instead of affirmation changed my outlook on life but it really did. Never before had I seen some so openly question their very own view and search for the truth rather than search for what backs up their view or idea. Great video, as always
Epiphanies can be painful, but we make them so. Your professor is clearly a devout scientist! Congrats to you both!!
That’s a great story and lesson! ❤
wanting to know the truth and rethinking you own knowledge, just to find out you've been wrong is a true sign of high intelligence. 👏👏👏 thinking that one is always right, on the other hand, is not
Reminds of when I was in 8th grade I argued with my elective science teacher about bullets firing in space his argument was based on the lack of oxygen and I knew that didnt matter since they can fire under water which doesn't have usable oxygen for combustion. I also liked guns growing up and its simple firearms knowledge that the use of self oxidizing smokeless propellants was a huge leap in their development. He reacted the opposite of your professor when we googled it and I was proven right.
"Power and Logic are not related." (-me) People concerned with logic aren't concerned when they're wrong, but people use _use logic_ to wield power get upset when someone else is right - their power is tied up in being right. (Note: that's the core to mansplaining too - explaining to assert dominance, not to bring equality of knowledge.)
Phenomenal explanation, one of the best I've ever seen and made me exclaim out aloud more than once.
Too bad it's a stupid explanation. Just think a bit: if the electrical energy is passing only around the wire, how it can ever reach the bulb filament and make it shine? The bulk filament is also a wire and according to this stupid clip, the electrical energy should not touch it.
@Exotic Spy Travel Ya, I believe the purpose of the video was to acknowledge the role and property of electromagnetism, but he never seems to realize where his emphasis falls apart. Namely, if it was just the fields around the wire, why would the wires need to be connected to the device. We could just lay electrical lines in proximity to things that we wanted to work for that matter. Also, it is very common for humans to simplify explanations in heed of making the understanding of said concept more intuitive. Yes, the analogy often used for electricity that it flows like water bugs me a bit too but it helps for practical understanding.
Definitely expected a different answer - as many years ago I plugged my phone in to top-up the charge but my battery actually reduced! Taking my charge backwards instead of increasing like it is meant to do! I can't remember what phone I was using at the time but I'm sure it happened more than once from that device. But not since then. It's true, I plugged my phone in to charge and watched it count backwards to depletion! Pretty strange!
Did you have an iPhone?
Something shorted to ground.
It's really interesting. The yellow lines propagating from the battery to the light bulb are sort of like the Earth's magnetic field to the moon. I think this is really cool.
Can I get an informed opinion on the Skin Effect please when it comes to audio? Does this really have the ability to impact the performance/propagation of an audio signal being transmitted down a cable? I've heard that it does, but at most it only has about a 3% effect on the signal, if that.
I wish we were taught this in physics class
I'm an electrician from the UK. This theory can be proven by holding a florescent tube near a power line. It will glow. My family didn't believe me so I showed them. So glad you explained this in a way they understands fully. Thankyou. Very clever.
A total physics noob here, Im sorry if this is a really dumb question: But if a florescent tube can glow because it gets energy from the power line, why dont we get electrocuted just by standing near a power line?
@Shiraishi Chan same doubt 🧐
@Shiraishi Chan I feel its all about distance and what you are wearing. I'm sure if you got close enough with no clothing and a direct line to ground. You may experience ark jumping. Its a very good question 🤔
@Shiraishi Chan hey EM waves not harm us ( like light not hurt you when it falls / passes through you) here energy is transferred by EM waves from the source to the electrical device which receive and convert to their known energy ( electrical) When you keep a fluorescent bulb near it takes those energy which was carried by em waves Same concept using in a current detector in a wire , we actually detect the em waves around wire which have more intensity near it
There is a difference between holding a power wire and stands near it
10:47 This must affect offshore wind projects that depend on long undersea cables, especially if you put them far enough out to not be eyesores from shore (usually over 30 miles). It shows that the more local an energy source is, the better.
Not really. 1 : More jacketing between electrical element and support strands will diminish the effect. 2: Power transmission doesn't have the same constraints as communication cabling 3: Glass fiber (among other materials) is great for structural support and won't affect your cable that way. Onshore winds are usually weaker and more variable than offshore. The best place to get energy is where it is abundant, adjusted by the cost of transporting it to its destination. Transmission losses are pretty low these days however.
I thought I understood how current flowed in a circuit... I've been lied to in school. The actual mechanism is absolutely fascinating.
The success of the clip is just due to switching the subject... Sometimes is electrons, sometimes current, sometimes energy. I think you were told the true about the mechanism for which current flows in a circuit. Energy flow might be represented in this way (perhaps better, not sure) which is familiar to those with somewhat physics education. We can use Poynting vector and fields to describe how energy goes. Yet you cannot split water (2H20 - > 2 H2 + O2) without an effective flow of electrons. This should clear the situation.
@antonio c You do in fact split water without outside electrons actually getting in. It just needs the energy from the electromagnetic fields to sort of decouple the electrons from the water molecules, perhaps, but the whole container itself IS neutral and stays neutral. I can't think of a case where you need to electrons to physically reach somewhere. It's all in the field, made because the electrons are moving ever so slightly, at least in DC ig.. This is college level chemistry, and I'm not sure how to simplify this stuff in a comment section. But... I tried.
Easiest way to realize it's not the push pull of electrons is that if it was, AC power would allow faster than light communication
Thank you. I love science and all things science. I have never understood this about electricity until this video. 😃
I could watch this 1000 more times and my brain would still believe electricity is either witch-craft or magic.
Your body is a natural electromagnetic beauty my friend.
The claims of this video are misleading, if you want to know more about it watch something made from a professional. Veritasium is very good entertainment and usually right about simpler things, but more complex matters he often gets wrong, just a layman repeating what he heared and might have misunderstood from others.
@Herner Weisenberg True, Thunderfoot has debunked some of this guy's vids.
@InuranusBrokoff thunder foot is a research chemist so while he has credentials in science he isn’t omnipotent with his scientific knowledge so he isn’t your go to authoritative source.
@SkyLark The body is also a capaciter with a known resistence.
I used to think that electrons flowed through the wires, but I eventually realized that that didn't make sense. However, I had no other explanation. This video is hard to follow, even though I'm currently studying physics/electricity, but it does give me a better idea of what is going on.
Wonderful comment. It remembers me how genuine were the people long ago. I was trying to explain how the tv's work, but many of them used to answer something like "yes, yes, but how can be so much / people be packed inside". This video could be difficult to follow for those expecting that it brings breakthrough answers - since 'packed' in a smart way, with millions of views, but imho it's only entertainment disguised as sci divulgation, and the sci-quality is inversely proportional to the number of viewers ("the impressed masses" that pretend to have understood) . I would say yet another idea about what +else+ +could+ be going on. There's also the electrical conductivity aspect. There's the fact that the telegraph cable example is wrong since it doesn't give proofs / measures. Btw, hoping to not annoy, in the present, as in the past, too many things given for granted. There's a playful saying, in plebs style, "It's all fault (of all the problems of today's world - to be intended) of those who invented the atoms". :)
If electrons don't flow then we can just drop the concept of current.
@Paul Frederick «If electrons don't flow then we can just drop the concept of current.» ---- The only certainty, out of common sense, is that something flows. So the current is there, electrons, or whatever else. Could be that it cannot be described, in suitable terms for our brains limited by the need of our space & matter analogies. To understand how much the science is impacting our vulgar world vs how much our vulgar world is impacting, requires knowledge of scientific and technological history, and quite a deep thinking. Or, in other words, is it the science to drive the achievements, or is it there to explain achievements that happened, and would happen again, without all that theory? Imho we need some epistemological genuine thinking paying attention to not get lost in abstract and sterile philosophy recitals. etc etc.
Dear Katherine, do not know if it could help, try to think in terms of Shakespeare's "What's in a name", then pass to "What's in a matter that isn't matter", and "What's in a energy". Be wary of those that pretend to know too much what's down there, in the too small to be seen or measured.
@Volty De Qua electrons don't flow like water unless they are water. But the hydraulic analogy can still be useful to visualize electricity. Just not all the time. It's how a lot of competent mechanics view electricity and it serves them well enough. So I won't quickly dismiss it myself.
This is a great video, thanks for making it! What if the lamp were in a sealed room? Assuming only the conductors pass through the walls of the room into the lamp how would the energy get their to power the lamp? This is going to keep me awake at night!
Great question, .... 😀great video..... unfortunately it is also my question. Please someone clarify....
Do you realize that electrical energy is a product of voltage and current? For any work to be done on the bulb, you need two things, voltage, and current. A conductor supplies these two properties. Electrical energy cannot be blocked, it can only be stopped if you cut the conductor. But as long as there is voltage and current in a conductor energy will flow.
Basically you got it. Be sure that the lamp will work. Though one can argue that the room is not sealed where the cable passes through the wall.... However you got it. It it true that current flows in cables. The rest is matter of PoV
You should have added in the demonstration to test the circuit with a meter after hitting the breaker, simple and easily taken for granted, but would be important for someone who doesnt do any electric work. Otherwise very informative
I wonder if in your hypothetical model, would vaccumn effect the energy vector?
This is the problem with the way engineering classes are often taught, equations vs. concepts. My college thermodynamics teacher was a ex-NASA contractor who had designed many rockets. Along with pithy explanations of what was actually happening in the exhaust bell of a rocket engine, he would add such intuitive axioms like "Once you've designed one rocket, you have designed them all". Of course he was talking about the repeated application of the laws of thermodynamics in virtually identical fashion, but they served to bring weighty issues down to earth. And this was very helpful to a visual thinker like me. Go Mizzou!
WOW! I'm 80 years old. Started learning electronics in the Army in 1959. We were taught the "Right Hand Rule" in the study of inductors and transformers. Although we knew about the magnetic field around conductors we never applied that knowledge like this. Thank you for teaching an old man a new trick.
Wow u still study Great grandpa ji🙏
@Abhinav Thank you. I love electricity in all forms. Except, of course, the CHAIR!
@Backlash do chairs really exist though
My mind is blown! Absolutely interesting. Makes me ponder what all this does to the human body and nature in the path…. Interesting
It's exciting that you've managed to sensationalize this kind of knowledge!
Surprising, I'd say
@antonio c You could say that he's brought new energy to this field
Thank you for this nice video . Now I think we can just point a battery toward a light bulb and it will light and drop the wire as long as conductor's free electrons has no job in delevering the energy. Morevere, if EM wave need guide we can use plastic or rubber instead of conducing wires . Should this worked I would believe your thought .
After watching this Vedio I understood the answer toone question that was I asked in one of the interviews The question was "what happens to the electrons at the place Where a current carrying conductor was cut with a knife while carrying current. Now I know the right answer. Thanks for this most interesting and logical concept of flow of current in an electric conductor.
finally some decent science information. More on Magnetic Resonance and Magnetic Fields please
The part about AC was mindblowing. The Poynting vector is S = E x B but if both E and B are reversed, then S = (-E) x (-B) so the energy flow stays the same!
For me, that was one of the only parts where I was like "oh, yeah, I know this one!" ahahah! Everything else was mind-blowing!
The visualation was the only why I would have understood that concept. Seeing the diagram, I immediately recognized it as just rotating the circuit along the axis. People who can look at numbers and gleen the same information are wizards as far as I'm concerned.
I absolutely read SEX the first time I saw your comment. Had to do a double take, lol.
@Francisco Power same lmao, I'm still shocked for everything else, I guess I have to watch the video a few more time
Thanks for the video. It is amazing explanation. I still have not got it 100% so need to re-watch several times.
A follow-up experiment should change the distance between the battery and the bulb and plot the time it takes for the bulb to light up as a function of that distance.
And this is the way to do ads and product placement. Thank you for it, coming from a person who hates most ads. Non-intrusive, explicit, not distractive or ignorantly manipulative, yet sufficiently in place as you use those in the video, and who wonders what they are, can find out in the end.
And at UHF frequencies, there is a phenomenon called skin effect. In electromagnetism, skin effect is the tendency of an alternating electric current to become distributed within a conductor such that the current density is largest near the surface of the conductor and decreases exponentially with greater depths in the conductor.
Great video and very interesting. I have a question though: how can we explain the wireless energy transfer using this principle where no wire/conductor is involved? (i.e. like wireless charging technology transferring energy through air based on magnetic field)
Wireless charging is mainly EM induction
I am a third year Physics uni student and I can onfindently say that you have managed to explain the poynting vector better than any of my professors ever have...
That’s because I bet none of them have ever taken any education classes (not required if you can believe that).
Isn't that the truth. And also after working in the field for many years. I learned so much more on the job. Hardly anything I learned in school whatsoever.. barely. Just the basics.
Bro you need to watch some Eric Dollard lectures... I would recommend "History and Theory of Electricity" and "Origins of Energy Synthesis" right here on CS-tv if you really want to get at understanding the essence of electrical phenomena. Just remember that a Theory of Everything has grave implications for Aerospace and Weapons development, and thus has major national security implications should it ever be out there for all the world to see, and thus why for the most part, we are kept in the dark as a member of the general public on topics that get deep into the essence of the reality of nature and natural philosophy!
@Jay Rock he misspelled confidently....so you're just as wrong? 😆
I often ask myself how much science suffers from confirmation bias. Great upload....THANKS !!! I wish everybody a positive life 🍄🌏👁😀
I think it was My Dad’s high school experiment or perhaps college in the 50’s as a electrical engineer to light up a light bulb by winding copper around a long six foot diameter drain pipe if I remember correctly it was like 50 feet long . He then placed the drain pipe on the ground under those very tall high tension electrical towers . The light bulb lit up . He told me that anyone who claims they understand electricity is wrong . There exist phenomena we still don’t understand about electricity .
I appreciate this video, thank you for the work you do and helping to move us forward.
He has moved people backwards, because he is Wrong.. . Electrical power, particular DC from a battery does NOT travel in the fields, but current inside the wire.
@Hugh Leyton The wire is electrics creating the field that travels inside and outside the wire. A transformer is proof that the flow isn't limited to the wire connection but it's induced by the electrification of the wire. This is why sensitive equipment requires shielded wiring or braided pairs.
@Hugh Leyton Have you ever heard not to cross wires perpendicular to each other, this is due to induction from the electromagnetic field that's generated by electrifying a circuit. I was originally taught the lumped element model for electrical theory when I was going to school to become ASE qualified. But some things didn't fully make sense, and now those questions are answered because the picture is more complete. He is describing the totality of the electromagnetic field and how it works. What was previously taught was the simplified version known as the lumped element model. His findings don't change the information that we know, but rather add to it. Giving us some more complete picture as I stated.
But it is WRONG. . The electrical energy does travel INSIDE the Wire, not by external fields, that is simply very wrong.. . . You have been had.
@Happy Home Projects Electrical Current, that is the moving Electrons INSIDE the wire will produce a circulating Magnetic field, which does not stretch very far, just mm. . . . . That is why the wires in Transformers are either very close together, or wrapped around a common Core. . . . But that is AC not DC. . . . Sensitive equipment may require shielding from high frequency signals and noise, NOT DC
This is a very interesting. As a HiFi Enthusiast some of the thing I hear about cables suddenly make sense. Since no electrons are transferred it must happen in the electric field. But if I connect a Current Clamp over both wires. Then I won’t measure anything. The magnetic field created by the electrons in both wires will cancel itself out. What am I missing?
This actually raises more questions than it answers.
yeah i think that was the intent of the video... classic youtuber ploy
Yeah. But it is so with all knowledge.
means there's more to learn as always;)
it SOO DOES!
naah everything is solved.
I am a grade 12 science student and I found this video really interesting.
The energy is extracted from the movement of the electrons at the load. It doesn't matter which direction that the electrons are moving, you can rectify it.
Thank you Veritassium. This is indeed the element of truth.
Great video but I have a question. When the basic circuit is connected 6:14 battery´s electric field that is neccesary for the energy being send through space is extended through the circuit at the speed of light. So in theory you have to wait for the field to extend before you recieve energy right? That would mean even if you have battery and light bulb next to each other you have to wait for electric field to extend through the circuit (Wouldn´t the answer to your question be 1 second?)
The story about the early transatlantic cables is great example of how things that seem intuitive at human scales don't always hold up in the grand scheme of things. It's kind of like how if I drop something on the ground, I can use Newton's equations about gravity to describe how the object falls perfectly. So there we go, that means Newtonian gravity is correct. Except no, because it falls apart when we start trying to use it in situations where gravity is much higher than we'd normally encounter here on Earth, like very close to a star. So you've got to come in with an explanation that seems counter-intuitive, but only because our normal perspective is limited.
The production quality has become insane! You're an inspiration to all us science communicators! Keep it up! :)
Tommy Gaming 🅥 Agreed - this channel is my inspiration for what I'd like my videos to become.
Do you have any idea what kind of money can be made on CS-tv?
@Ryan Lush Yeah I do, but still you need to build that business up from the ground. And when there, put in the effort to reinvest that money into high quality production :)
This is a very late question, but what about insulation? Does the insulated line limit the surrounding flux of electromagnetic energy? Does insulation limit the energy to limited area surrounding the wire itself?
could someone explain how this interacts w' more than one object, for example instead of just one light globe, add a resistor linked in with 2 or 3 light globes and say a speaker. i see how it works and it makes sense I'm just having issues visualising it w' multiple objects in the circuit. thanks for the vid tho really usful, i may only be doing a level 2 in electronics but it still fun to dive a little deeper sometimes :)
It's intriguing and counter-intuitive. What if we place the light bulb inside a box shielding all EM waves?
I think this is a well-produced video that jumps to both right and wrong conclusions. Okay, energy is transmitted by the electromagnetic field. But the electrons passing through the wires play their part. Otherwise, a broken wire would conduct energy just as well as a good wire. Maybe I could agree with your answer just because of the capacitance of the proposed system, but as a RESIDUAL energy transferer.
Dang. Can't say I ever knew or even heard about that. Is this also the reason why there are so many new health problems that are acclaimed to come from Electricity? Or are those more likely to be caused by Radio waves and whatever Bluetooth and Data uses?
I think one of the most difficult things about the Poynting vector is to visualise the cross product in your mind. That video with all fields represented in space is extremely helpful and should be shown in EM courses.
The poynting vector visualization is wrong though! Vectors are much closer to the wires. Unfortunately a misconception in this video
@marvinalbert not wrong, just not 100% to scale is what you meant.
@Isaac Groen Actually arrow directions are pretty wrong, they're much more parallel to the wires.
The vector isn’t a real thing, it’s just a mathematical device.
Once again I remember why I nearly failed E&M in college.
A coupe of things I don’t understand: if electricity creates a kind of ‘aura’ around the wire, why are cables insulated? Presumably, this doesn’t actually insulate the electrical charge. So is it there to stop other types of signal (radio waves?) from interfering with the signal? Secondly, what about circuits scored into silicon wafers? In this case, the signal must travel via elections due to the small size of the signal path? Or do circuits like this create electromagnetic auras of their own?
I believe the bit about the Energy being in the fields, but if the 1/c answer is correct and hence the field can propagate straight through space from the battery to the bulb without having to go along the (long) wire, then this begs the question as to why the wire is necessary. You should also be able to set up a sort of „quantum erasure“ type experiment in which at the far end of the long wing loop the wire is cut through after the light bulb lights up, but before the information that the wire is no longer connected could travel or be seen at the bulb. So what happens if you connect the switch and then severe the loop at the far end at a time t 1/c< t < 1s? And when would the bulb extinguish? If it extinguishes in time less than 1second then you are successfully transmitting the information as to whether the wire is severed faster than light. you could use this to make a faster than light morse-code transmitter. Please rebutt.
One thing to be clear is that even though some Poynting vector can travel through empty space outside the wire, the majority of the energy is still travel along the wire. So yes, the bulb can START to light up very quickly, but how long the WHOLE energy transmits to the bulb still subjects to the length of the wire. I’m open for discussion.
Such a well done video that I listened to the whole ad at the end. I dislike ads but so appreciated the information.
Mr. Veritasium, This is great! I love your videos. I see here that the switch and the power supply are right next to each other. What would happen if the switch stayed where it is, but the battery was placed 300,000 km away? Is the speed at which the light turns on measured from the switch or from the power supply?
From the power supply
I’ve been an electronic technician since the 90’s and I remember one of my electronics instructors explaining this to us and it still blows my mind all these years later. Fascinating video, thank you for posting.
Suppose the bulb in the diagram was at the middle of the top line of the square of wires would the field arrows that were in the diagram still move towards the lightbulb?
I think it is a bit easier to picture when thinking about microwave Radio Frequency (RF): they literally have wave-guides that look like steel pipes. From the shapes of these "pipes", it is clear that all the energy is in the empty space inside the "pipe" rather than in the conductor on the surface.
I am not convinced. I think the E field needs to propagate along the wire to have enough intensity to light up the bulb. Otherwise, if I disconnect the bulb from the wire, according to the video, it seems the light would still be on, which cannot be right. Would you might help me understand this?
Can you explain something? When I switch my house light on, what distance is taken into equasion? From lightbulb to nearest transformer?
@Yogurtmaker From the switch to the light.
I'm so chuffed I got the right answer and could understand this, school served well - thank you Mr. Evans.
Deeply intriguing. But why does a person only get shocked when he touches a circuit's conductive wire or a battery terminal? What happens then? How far outside the conductor do the electrical and magnetic fields extend? Why is there no effect if you just come into (or near?) one or both of those fields? Thank you for the video but it's taking me some effort to get the whole picture.
this question is always coming to my mind, and never I can find a satisfied answer ... Thank you so much
Your video is excellent thank you, You're a great teacher
Subscribed. You're a gifted orator. Great stuff.
Okay, but If I stood at one of the lines extremes with a pair of scissors and cut the line, how long would it take for the light bulb to turn off? Would it take half a second for the collapse of the electromagnetic field? Or would it happen nearly instantly? If its the latter we could use a switch to transmit information nearly instantly over astromonical distances. If its the former then I'm confused as to how the field propogates to the lightbulb near instantly.
My grandmother lived on a very remote and isolated island in Norway. When they first got electricity, they had one lightbulb connection hanging from the ceiling in the best living-room (it was only used when having fine visitors). The thing was that when the electrician first lay out the cables, they had no bulb to put in the socket. Also the electricity was not yet connected to the house but would be soon. So each night they put a bucket under the empty socket just in case the electricity would be connected while they was sleeping. Not to spill anything on the floor.
Lol that's amazing.
A colleague's grandparents, living on farm land in Belgium, would dress up on Sunday to watch television, thinking the presentator was actually talking to them and did see them.
I have a friend who turns off the switches on all his unused power points - not because of safety, even though that's sensible - but because he believes electricity pours out when there's nothing plugged in, wasting his money.
This would have been a great topic if I were and electrician or a psychist.
very very interesting! I wonder if there would be a delay if the bulb was placed at the far end of the lines, away from the battery source?
If there was no delay then there'd be no such thing as network latency.
Doesnt this mean that by having a switch on one end of the universe and a lightbulb on the other, we could theoretically transfer information faster than the speed of light?
Well, while we are picking at things, my HS math teacher would slap us on the wrist if we said "over" because that is not a math function. We were required to say "divided by" since that leads to better understanding. That has stuck with me for over a half century. Cool presentation.
1. There was always the suspicion that something was off. I keep telling my semiconductor professor that the poles could just teleport. He was not amused. 2. There was the wireless light bulb scene from Nikola Tesla in film The Prestige (2006). I think most people would know that there are ways to transmit energy wireless as long as we make a complete circuit. However, `didn't know that "the field" is the primary way of transferring energy that we have been doing all this time since we adopted Tesla's AC method of transferring power. 3. At long last, I can now explain why we can still use the "electrons as water" analogy to study basic AC circuits is still valid (even though it makes little sense). Simply, our primary electric energy is transferred by intention and not by phenomena. As long as the intention is made clear to the universe, the universe will oblige do perform the transfer.
I think the best part of this video isn't just the information it presents, but also the conversation it sparks in the comments! People asking questions, people trying to understand what's being said, and even people providing counter-arguments in certain scenarios where what Derek explains doesn't seem to match up. I think having civil discussions helps a ton, thanks Derek + the Veritasium community! This video and the comment section is genuinely interesting to go through
People just figured out that he is wrong 🙂
@markmd9 where's your evidence?
I think he is being somewhat intentionally deceptive/vague in the video on purpose to cause this :P He's not wrong, it's just a weird perspective.
@markmd9 He is partially correct and partially wrong. There will be some small energy transfer between the bulb and the battery in 1/c but the bulk will happen after more than 1s.
At first I really struggled to understand this, but the way I see it is that yes, the energy is carried in the fields surrounding the wire, but that energy is "useless" unless it can persuade the odd electron to move, or shuffle or vibrate in some way. Once the electron is on the move it can do something useful, like heat something up or power a lightbulb. It also explains why you can hold an insulated cable and not "feel" the energy potential of the fields surrounding the wire. Only, when you cut away the insulation and give the already resident electrons an easy option will you experience the potential energy of the fields.
Excellent processings of science and analysation. This is a very enjoyable episode. There are breaks in the Power-line, electrons do not flow all the way through the wires. If the flow of current is in two ways, why does energy flow through one wire? Excellent 👍🏻 questioning and processing. James Maxwell says light is made up of ausolating magnetic and electromagnetic fields. Conservation of energy, can be traced through the transmitted electromagnetic energy . They tracked the electromagnetic energy electromagnetic and magnetic fields . Anytime there is electromagnetic fields, and magnetic fields , energy can be measured. Excellent processings and illustration! A electro is external from the outside of ALEESHA THE TELEPHONE and magnetic fields a in . The energy is traveling through the fields incredibly fast. The electrons barely move. The same analysis between AC, is the same as DC. There was difficulties in the cables put under the sea, due to the blockage of the fields, they had to figure out , that you need the air space for the magnetic and electromagnetic fields.
This is the doubt I had from my 9th grade.. Now Got it cleared😂tq
The traditional explanation that we were taught in school seems to have been good enough in order to produce and use electricity in various ways for the last hundred years. Oh my god, it was all wrong. My light bulbs and electric motors stopped working when they learned the truth. It was all a dream.