The Big Misconception About Electricity

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  • Published on Nov 18, 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.
    ▀▀▀
    References:
    A great video about the Poynting vector by the Science Asylum: thexvid.com/video/C7tQJ42nGno/video.html
    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
    ▀▀▀
    Special thanks to Patreon supporters: Luis Felipe, Anton Ragin, Paul Peijzel, S S, Benedikt Heinen, Diffbot, Micah Mangione, Juan Benet, Ruslan Khroma, Richard Sundvall, Lee Redden, Sam Lutfi, MJP, Gnare, Nick DiCandilo, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Ruslan Khroma, Robert Blum, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson,Ron Neal
    Written by Derek Muller and Petr Lebedev
    Animation by Mike Radjabov and Iván 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

Comments • 68 704

  • Haven DeZeeuw
    Haven DeZeeuw 5 months ago +13453

    I’m so glad this video exists. I use to completely not even understand how electricity worked, and now I still don’t.

  • Bee Dub
    Bee Dub 26 days ago +72

    This is precisely why a "ticker" or non contact voltage tester works. It will start to blink and tick, slightly before making contact with the wire, even through the wire's jacket or insulation.

    • Jiboo!
      Jiboo! Day ago

      @T S im getting my bs in engineering physics and my masters in electrical, also i TA for college level physics 200. Tell me again who is more qualified? Were talking about poynting vectors because the original comment was talking about it.

    • Jiboo!
      Jiboo! Day ago

      @Mark II he explains it in the video, electrons hit nuclei and impart some kinetic energy

    • Jiboo!
      Jiboo! Day ago

      @T S electric and magnetic flux arent vectors as theyre the dot product of two vectors, making it a scalar. The fields themselves are vectors (im using field here as in the electric and magnetic field vectors)

    • T S
      T S Day ago

      @Jiboo! also it isn’t the cross product of two fields. It the cross product of two vectors, one is a field and the other is flux

  • Ingsoc
    Ingsoc 24 days ago +208

    So a question. If the energy doesn’t really flow and is conducted by fields outside of the wire, how does one get electrocuted by only touching the conductor vs the outer wire sheath, and why does the energy seemingly flow through a person and not around them like a wire?

    • mr grumpy
      mr grumpy 2 days ago

      that deserves some thought

    • Eric Herrera
      Eric Herrera 2 days ago

      Science and reasons

    • Commenter Of Truth
      Commenter Of Truth 7 days ago

      ​@Patinho battery exudes its energy to alter the fields and move electrons in a certain way. then the fields are produced.

    • Commenter Of Truth
      Commenter Of Truth 7 days ago

      ​@Aditya Agarwal in that case the fields and magnetism are much greater. which is why they are so high up.... which he explained in the vid. Idk if youre either explaining to someone that wires CAN electrocute them when not touching, or if you were making an inane claim agains how fields worked. ill choose to believe the first thing I said lol.

    • Commenter Of Truth
      Commenter Of Truth 7 days ago

      for the same reason why the wire itself moves the electrons you person

  • Steven Lightfoot
    Steven Lightfoot 23 days ago +22

    You have blown my mind. I am a Mech Eng, and have never heard of the Poynting Vector, but have been struggling to understand power flow direction for at least five years. I think this will lead me to the answer.

  • docbrown237
    docbrown237 23 days ago +13

    At last!! I had a high school teacher 54 years ago (Dr. Schoenfeld) that beat your electrical pressure/EM field transfer of 'electricity' through a circuit in our heads. Later, I recall on a test in college Physics 110 where the correct (or accepted) answer was always ' ...by virtue of the flow of electrons through a conductor'. I always wondered how many of us students took a fraction of a loss in our GPA due to this belief. Excellent video explaining how capacitance (or inductance) play a role in something most everyone takes for granted. More I²R to you!

  • MattMGK
    MattMGK 3 months ago +1548

    After watching this video I can confidently say I understand less about how electricity works than I did before.

    • Puh Chew E. Chomp
      Puh Chew E. Chomp 11 days ago

      @socially unacceptable Oh? That's interesting. Meditate to rid one's self of delusions to see the truth. I've learned something new, thank you.

    • socially unacceptable
      socially unacceptable 11 days ago +1

      @Puh Chew E. Chomp that's some typical zen wisdom there. in buddhism you call those delusions and you're supposed to meditate to rid yourself of them.

    • Monkeysrock
      Monkeysrock 20 days ago +1

      The problem might be because when someone says electricity, most people think its the stuff that turns on devices and what the power company charges you for. Electricity is a field, though, and for the most part people are using the word as a replacement for energy. Which is why the power/energy/electric plant are all the same thing. Try to think of it differently. An electric field is generated perpendicular to a magnetic field, and the orientation of those fields tell you the direction of energy, which is what we pay for and is what turns on our lights. Even a lightbuld is just the little wire in the glass absorbing energy and the super tiny vibrations in the material are heating it up so it can glow.
      This may not help but im not a good science communicator and it gets hard when one field being present almost guarantees the other is too so energy is moving no matter what.
      I guess the fast way to see it is that as long as the fields are present, energy flows, but you need stronger fields for more flow, and we use wires to help maintain the fields. That simplification makes confusions though, so try to just recognize that an electric field is not what the power plant sells, and that energy is not electricity. Electricity is just a way to let energy move.

    • Monkeysrock
      Monkeysrock 20 days ago

      @55dbk Tesla heavily disagrees but he died young so Edison is very happy to keep selling you wire even though we use copper over steel now.

    • Thomas Winston Montague
      Thomas Winston Montague 26 days ago

      @Alan Wannemaker You mean be open to pretending that the explanation makes sense? Sure, why not? Only somebody who fully understood the explanation could prove another person's misunderstanding. So since nobody fully understands it (even the experts disagreed about something he glossed over) , any given claim that a person understands the explanation could never be refuted. Unfortunately, that still doesn't make the claim to be true. But as long as everybody thinks I'm right or rather, nobody think I'm wrong, who cares what is true?

  • Freedomfixer_Flying
    Freedomfixer_Flying Month ago +7

    Another thing that substantiates this is the fact that high power transmission lines are hollow. Not only to reduce weight, but the fields only travel along the skin of the conductor. Larger Solid conductors are less efficient at larger diameters because the fields only penetrate about 5/16" or 8mm. This is why they are hollow.

  • terrell lewis
    terrell lewis 23 days ago +6

    I was an EE and understand the flow of electricity through wires and circuts. This illustration is the best explanation I've seen. Thanks.

    • brian g.
      brian g. 20 days ago

      I have a good basic understanding as a telephone tech testing lines I was trained by an old timer with 30 yr experience. Have to say I don't understand anything here.

    • Thanatos
      Thanatos 21 day ago +4

      Make sure to check out the update video released today, he mentions a few mistakes made and clarifies further

  • Fr34k 0.o
    Fr34k 0.o 23 days ago +8

    Love watching Your videos about mathematics and physics. A real good source of information and study for independent research :)

  • MFM
    MFM 18 days ago +4

    i would say yes, because i have seen multiple arcs from powerlines over the years from when people get too close with construction vehicles. the higher the voltage, the higher the wire, because you need it to be farther away, as the field is larger.

  • AT
    AT Month ago +806

    The fundamental law of physics: electricity disappear if you stop paying bills.

  • Samuel Schneider
    Samuel Schneider 24 days ago +6

    So in theory you could disrupt, strengthen or average this energy transfer by influencing this magnetic flux? Would this be similar to the application of the ferrite bead you see on charging cables?

    • John Hunter
      John Hunter 24 days ago

      thanks for letting me know what that ferrite bead is for and what it is called. I always wondered and now I know!

  • Randy Liu
    Randy Liu 15 days ago +2

    I've been actually thinking about this for some time already. Thanks for the video, although I still don't get some idea
    1. 7"15, the current inside the wires create magnetic field outside the wires -- Shouldn't magnetic field created only when "current changes direction"?
    2. 6"18, when circuit is connected, its electric field extends through the circuit at the speed of light -- How (why) does the electric field spread through circuit? And the speed of light is the light speed in air or in wires (although I don't know how to define speed of light in non transparent object)
    3. 6"31, (electrons) depleted elsewhere -- How is "deplete" defined?
    4. 7"00, the charge on the surface of the conductors also creates an electric field outside the wires -- So which electric field combined with the magnetic field (created by the electron movement -- my 1st question) delivers energy? The electric field from battery that makes electron to start moving? Or the electric field created by the surface charge of conductors?
    5. 8"13, the energy flow is a space integration of the complete circuit, include power source, power drain and conductor, if I understand this part correctly; then the question is, if power source and drain are next to each other, but conductor spread out a long way (1 light second, as your imaginary experiment), the energy flow "along the conductor" only reaches power drain gradually (behind the energy from source "jump to drain", because they are next to each other), so the power drain receives full energy 1 sec later?

  • Tim Appleby
    Tim Appleby Month ago +1

    If electricity didn't work this way, how would EMPs be effective at knocking out a grid? Seems reasonable to me that if the electromagnetism in closed end circuits opposite the energy delivery systems suddenly lost their energy, it wouldn't be able to be easily replenished.

  • Georgi Georgiev
    Georgi Georgiev Month ago +2

    Having to do transformation using Maxwell's equations was both the most fascinating thing and the most computationally arduous in the classroom, but because the mathematics was so beautiful it did bring much joy. No regrets.

  • Dylan Dailey
    Dylan Dailey 6 months ago +4599

    EE here; I think most of this info is technically correct, but potentially misleading in some areas.
    For one, while it's true that energy is transferred in the space around a conductor, as opposed to through the conductor, the *vast* majority of that transfer is taking place *extremely* close to the conductor (we're talking millimeters, typically), due to both the magnetic and electric field strengths decreasing exponentially with distance from the conductor. So in reality, the energy being transferred actually decreases superexponentially with distance from the conductor. Now, in power lines, the ground is still a concern because it's a very long conductor, carrying very high voltage, at very high currents; it's a somewhat extreme case. Yet, even though the cable is *miles* long, we only need to separate it from the ground by tens of meters to significantly reduce losses over that long distance. Furthermore, the ground is only a problem because power lines are AC. If they were DC, you could lay the cable right on the ground, and you wouldn't get any significant energy loss.
    Edit: see below, the dropoff is not actually superexponential, but the general idea that energy transfer is greater closer to the conductor is still accurate.
    For two, the analogy of electron flow being like water through a tube is actually still accurate in the case of the undersea transmission line. The metal rings around the cable cause a change in electrical impedance for that section of the cable. In the case of water in a tube, this would be analogous to having an air bubble trapped in your tube. As a pressure wave travels through the water, it will suddenly hit this air pocket, which is far more compressible than the water (i.e. has a different impedance), which will cause the waveform to distort in precisely the same manner as the electric wave does in the cable. Some energy will pass through the bubble, creating your distorted (attenuated) waveform, and the rest of the energy will actually become a wave reflected back in the other direction. This is precisely what's causing the distortions in the undersea transmission line. There's a bunch of reflected waves bounding back and forth between all the iron rings that stretch and distort the original signal. (for the real electrical nerds, check out "time domain reflectometry", which uses this principle to precisely detect where a fault exists on a power line)
    Third; yes, energy transfer from the switch to the bulb will occur in 1/c time (by the way, I think you could clarify this by representing it as d/c time, where d is distance from the switch to the bulb. You never really state where the 1 comes from in that equation (at first I thought you were implying it was a constant value, unrelated to this distance)). And yes, you do clarify that it will only be a fraction of the steady state energy. But I think you should stress that this would be an *extremely* small portion of that steady state energy. The initial energy that the bulb receives will only be due to the capacitive and magnetic coupling between the two long portions of the conductor. And in the case of wire separated by 1 meter, both the capacitive and magnetic coupling would be practically zero. This again is due in part to the exponentially decaying electrical and magnetic field strengths with distance from the conductor, as well as the poor electric and magnetic permiativity of the dielectric (air) between the conductors.
    Fourth; addressing your question about "why is energy transferred during one half cycle, but not returned back to the plant in the other half of the cycle", I think your physical demonstration actually explains that perfectly. No matter which end of the chain you pull, there's something down the line offering resistance to the motion of the chain. Heck, you even get friction between the chain and the tube, which is like resistance in electrical conductors. However, if you attached a sort of clock spring to your wheel (such that the spring always worked to return the wheel to its at-rest position), you would indeed see some energy returned to the power plant (you) on the second half of the cycle. This is analogous to powering a capacitive load with AC.

    • Commenter Of Truth
      Commenter Of Truth 7 days ago

      it just sounds like you gave more information on what he already said, to clarify or slightly adjust into a more detailed format. if its misleading to anyone, I understand that part. but they should dive a bit deeper in understanding anyways lol. so the misleading aspect is autosolved by human intuition. except, a lot of people seem to lack that.

    • Bangkit
      Bangkit 24 days ago

      Thank you, its much easier to understand!

    • Eddie C. - The Raven
      Eddie C. - The Raven  26 days ago

      Just some misleading areas :) You have a much more eloquent way of calling bs than I do

    • Merilix2
      Merilix2 Month ago

      @Sorin Craciun In fact, the answer 1/c doesn't make any sense at all because 1/c is not a unit of time. 1/c is just a constant one can use to translate between time and length units but is neither of both by itself. Unit calculation is somewhat basic physics I'd say.

    • Medi
      Medi Month ago

      My god, the video was pretty misleading and at times downright incorrect, and now we have another not-so-correct comment by @Dylan Daily who confuses the hell out of people. In short, no, the answer is NOT 1/c, "for all practical purposes". The energy must travel along the wires to get to the bulb, again for all practical purposes. Many have explained in the comments, so I won't do it again.

  • Dexter Lakeriver
    Dexter Lakeriver 26 days ago +2

    I my electrodynamic class we used this poynting vector as well, but for electrical application (unless RF applications) most problems can be solved by considereing each wire as an resistor, inductor and capacitor at the same time. Many people knows about the RF cables for television, The shielded ones, they are used in a what called "75 Ohm System" in which the properies are well defined, and it is much easier to use this concept instead of using poynting vector directly, of course they easy considereation can be derived from the poynting vector. The electron is moving picture which is shown heare is a little bit missleading in terms of that the electron have to travel from the source to the bulb. It is more like you have a all electrons in place only kick one after another until the pulse is reaching the bulb plus the velocity of the electrons itselfs. And yes moving charges creates mag. fields, which is a major damping faktor of the initial pulse. The phenomena is called inductance. So it is not something new or changing to use the poynting vector directly to calculate the energy transfer it can sometimes be convinient to use it. Unless you don't have to do something with RF applications use the electron as electrical energy carrier and ohm's law. have a good one :)

  • ray Nic
    ray Nic Month ago +8

    I always assumed it was more like a Newtons cradle type of thing. I mean one electron stimulates the next, it does really get displaced and run the distance. Waves in the ocean move similarly. A wave travelling at 20 mph isn't moving all the particles in the wave at 20 mph. The particles are barely moving, but the energy pushing one particle into another keeps the wave moving. With the exception of a breaking wave or when they run out of resistance at the beach and run up.

    • eb bay
      eb bay 6 days ago

      exactly correct its not the flow but the movement that gives the power

    • Amos Backstrom
      Amos Backstrom Month ago

      You're still basically right. However a small amount of energy is transmitted through the air at the speed of light. The switch is so close to the bulb so it "receives" this energy first (picks it up like an antenna). This amount of energy is negligible and would be practically undetectable, nevermind being able to light a bulb with it!
      What Veritasium did here is very misleading in my opinion. While he did a good job explaining certain aspects of the science, overall he's cherry picking variables to push a narrative, which leads to misunderstanding.

  • Lore M
    Lore M 20 days ago +9

    I LOVED this and you explained it so well, I thank you so much.
    In 2017 I was privileged to visit several museums in Glasgow, Scotland and learned a lot about Kelvin (whom I’d never heard of) and saw several of his inventions. I was fascinated by his first tide machine…
    One of the things that I appreciated in your presentation here, is the different theories purported in trying to understand the flow of electricity. It reminds me of Isaiah 40:26 where it speaks of the creator is full of dynamic energy…so hearing and seeing your explanation here (thus putting to rest my erroneous belief that the energy just followed the wire…) makes me appreciate its creator even more. To me, logic demands that these complex and unfailing laws have been designed. I’m certain that there are even more refinements in understanding (in all scientific fields) are yet on the horizon. Thanks for making learning these things so interesting and fun (for me) I appreciate being your student, now. 👏👏👏

  • Peter
    Peter 14 days ago +1

    I know that when they installed the transatlantic cable they had to splice the cables a number of times, but why didn't they test it on land before dropping it? I assumed the conductive water was what caused the interference, not the iron sheath.

  • Coach
    Coach Month ago +430

    I could watch this 1000 more times and my brain would still believe electricity is either witch-craft or magic.

    • Coach
      Coach 4 days ago

      @IT Security Solutions, Inc. Ok

    • IT Security Solutions, Inc.
      IT Security Solutions, Inc. 7 days ago

      As an Electrical Engineer, most of technology which is not understood is said to resemble Magic. Electricity is not Magic, just energy which is everywhere. If you consider this Magic or Witch-craft, that may be your Paradigm.

    • Mike Steele
      Mike Steele 7 days ago +1

      @Herner Weisenberg he is not a lay person - he has at least a masters degree in physics and was a college physics professor. Also, the guy behind the channel itself has a PhD in physics education. They frequently educate other physics professors.

    • Limitlez
      Limitlez 8 days ago

      @InuranusBrokoff Thunderfoot is not a reliable source either. Maybe he's gotten better, but a couple years ago, he was realllly bad

  • EtherFi
    EtherFi 24 days ago +55

    I'd like to re-imagine this question a little. Let's not stop at a wire that's 1 lightsecond long. Let's make it 1 lightyear long. Now, let's turn the bulb on and off at one second intervals. According to this, the bulb turning on and off will still happen nearly instantaneously vs the switch. Now, tell me what happens when someone half a lightyear away cuts the wire....

    • Commenter Of Truth
      Commenter Of Truth 7 days ago

      ​@Andrew Seligman Id say the fields react immediately, as they arent some kind of choice making entities. but their produced fields arent running like they were a moment ago, so they 'begin' to shrink their field i.e. energy. so if the system is disrupted, it ends at the speed of light.

    • Visa Valpola
      Visa Valpola 16 days ago

      ​@Jenni Armstrong The formula veritasium used and the point of the video was that for some energy to get to the lamp it will not matter how long the cable is. For some energy to get through the only thing that matters is the distance between the switch and the lamp. So the 1/c s in the video should be 1m/c which is 1 m / (299 792 458 m / s) which is about 0.0000000033356 seconds. I said that a small amount of energy would get there almost instantly which was referencing this time. It is not however the full voltage and it does not travel along the wires and therefore the lenght of the wire does not matter for it. But as it is only a small part of the electricity I pointed out that for the full amount you would take a lot longer and that amount is not insignificant. The point of the video isn't that most of the energy doesn't travel in the magnetic fields very close to the surface of the wires (which is why we use them) but that many people don't understand that the energy is actually transmitted through fields and some of those fields can travel through air. He was not trying to deny that most of the energy follows the wire just saying that contrary to popular belief some doesn't.

    • Visa Valpola
      Visa Valpola 16 days ago

      @Jenni Armstrong I did catch the point of the video it's just that it's missing a part of the formula the correct formula is 1 ly/c for the full energy and 1 m/c for the partial energy. Veritasium missed the unit of distance in the formula and admitted to it in a later video. It's not a big problem to do that but apparently it has caused you to misunderstand the calculations.

    • Jenni Armstrong
      Jenni Armstrong 16 days ago

      @Visa Valpola you didn't catch the point of the video. The formula for a 1 light second cable is 1/c seconds for the lamp to light. Ergo, if the cable is a light year, it takes 1c years for the lamp to light.

    • Andrew Seligman
      Andrew Seligman 21 day ago

      @Visa Valpola Thanks Visa. That makes sense.

  • heavyhappylove Burger
    heavyhappylove Burger Month ago +2

    I only have electrical theory up until N3. Electronics n2. I am 46yrs of age and let me tell you something...you guys are all brilliant and it is so exciting to be able to learn through a medium like today. I would have never BELIEVED in 1998 that the present DAY, through mankinds advancements in tech was REAL. Thxfull for all the engineers for all their hard work in making earth incredibly exciting. i have depression and every time i see things like today even though sometime i get hacked, and stil it gives me hope for a chance on a future. @@@@@This also my my first sincere comment of 2022. @@@@

  • David W
    David W Month ago +3

    This is great info. I learned electron theory in the 70's USN electronics program. Of course, we've learned more between then and now than we had up to that time. I did question using the term "lie" for what we learned. I'd think it was taching to the best we knew, or maybe to the level a non-physicist could grasp... was isa "lie"?

  • Jens Schiønning Larsen
    Jens Schiønning Larsen 23 days ago +2

    Oh great I got a D - in my high school Physics exam back in 1997, for explaining that the way electricity is being described in the school books are wrong and it was more like what you described it to be.
    Glad to know I could have been an engineer If I had gotten that A in Physics.

  • Mr. Jason
    Mr. Jason 6 months ago +552

    This actually raises more questions than it answers.

    • Fullson Chuang
      Fullson Chuang 2 months ago

      @noise5555 1/c is time, not velocity

    • gordo teton
      gordo teton 2 months ago +1

      welcome to actual science

    • Q Revere
      Q Revere 5 months ago

      @Jaden Prayers for blessings of wisdom and good fortune.

    • Jaden
      Jaden 5 months ago

      @Q Revere such big words yet you can't seem to find the period button. Here copy and paste mine ".".

    • Q Revere
      Q Revere 5 months ago

      @Marko Topolnik This would make much more sense, while also making many much more angry, if you incorporated dielectricity into your model.

  • Khalid Ismail
    Khalid Ismail Month ago +2

    Thank you very much for all the work you've done.
    I am Electrical and Electronic Engineering Student and this gave me answers I seeked much.

  • Junk Mail
    Junk Mail Month ago +1

    Electroboom, I'm a retired electrical engineer. I love your video. I wanted to say, importantly, the word is impedance NOT impotence!!! Yours is the third of three videos I've watched on this. First was Veritasiums, then Dave at EEVblog, then yours. Dave said that we engineers think about things differently. That we have tools to analyze things and validly track physics and the rules of science. You fellows have collectively reminded me of much of the complexity we were trained to understand and analyze and calculate. I've much forgotten what I was trained and educated to deal with. I've been so browbeaten by the mindless politics and public chaos of people and the media news etc. I've forgotten the promises of my youth and education. TheXvid, multimedia and Internet is a terrible way to waste a capable mind. You've helped to retrieve my past capabilities. Thank you. Amind is a terrible thing to waste, and you've given me a wake-up call.

  • Tim eTraveller
    Tim eTraveller 3 days ago

    The conductive wire confines the energy fields to itself with the electrons inside. The energy fields act on the electrons inside or you can say the the electrons respond to the fields at the speed of light or the speed of the fields. But some portions of the energy fields radiate out around the wires, that's why you have "dirty electricity". You can have energy transfers without using the wires and that will be radiated fields like cell signals and wifi signals. But their intensity is less concentrated compared to the energy transfers through the wires. That's why you get electrocuted easier by the wire than by radiated signals. But you can still get electrocuted but a flash thunder or a laser beam. So it's all a matter of intensity of energy and energy transfer. Energy transfer can happen inside a wire or without a wire but none of the transfers is 100% because of capacitance, inductance, and impedance, and space. That's how I understand electricity as a EE major student.

  • Richard Lexen
    Richard Lexen Month ago +1

    Thank you so much for your videos! These are really inspiring and I learn so much especially in quantum physics.
    There is a but for this video. The explanation of AC power supply is simplified but correct. But I think the answer to your thought experiment is incorrect. (And I think you mean 1m/c.)The wave is guided along the wires, in the fields that’s correct, and therefore the energy is also transferred along the wire. Even the fields start spreading into space from the beginning at the switch, these fields are not strong enough to bring the energy directly to the bulb. If you were right, this would mean, that the wave at the bulb would reach almost the same amplitude as at the switch/source. But you know, this does not happen because the fields are spreading in all directions, not only towards the bulb. The thought experiment is not suitable anyway, because it is about DC. It does not really fit here.
    Another misconclusion is the necessary height of the power lines. The height is only determined by isolation distance. The lines could be much lower, but then you could not walk and drive underneath the lines. For high voltage we also use 3-phase systems. The fields along the wires compensate each other already after a short distance. So the influence of the earth is negligible with regard to energy flow.

  • lv8pv
    lv8pv 6 months ago +171

    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.

    • lv8pv
      lv8pv 29 days ago

      ​@michange3141592 hehe my mother saw a television the first time when her father brought here with him to visit someone in the city. After a good long while she ask her father why they had a small man inside a box

    • SkyLark
      SkyLark Month ago +1

      They applied themselves to understand it . They even respected it. Interesting

    • creative intentions
      creative intentions 6 months ago +3

      That's crazy. It's not water

    • Cmdr Sighman
      Cmdr Sighman 6 months ago +4

      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.

    • michange3141592
      michange3141592 6 months ago +7

      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.

  • Matteo Cucchi
    Matteo Cucchi Month ago +1

    Great video, thanks. However, something is not in line with my intuition. Yes, electromagnetic energy gets to the bulb from the battery in no time. But is this energy that is lighting up the bulb? How does the resistance of the wire, the actual motion of electrons, and the voltage drop get into the picture?
    For example, some devices (LEDs, transistors..) would need a voltage to work, rather than electron flow. Does this electromagnetic energy make them work without "knowing" what's on the wire? i.e. its resistance.
    Moreover, if one assumes no resistance of the wire, we are assuming infinitely high electrical mobility, which reflects on infinitely high drift velocity of the electrons, and not a fraction of millimeter as stated in the video.
    On the contrary, if one assumes finite mobility, also the resistance is finite, and will be very large for such a long cable...and electrons will move very slowly and the light bulb will hardly turn on.
    Not sure I am raising good points, but i can't generalize the lesson of the video to other examples.

  • PhauxtoN
    PhauxtoN Month ago +3

    8:22 That's a great point. We don't pay for electrons. We pay for fuel to run electrical generators.

  • Cly Roth
    Cly Roth 11 days ago +2

    As this vid explains (without saying the words), the photon is the force carrier particle for electromagnetism, not the electron. All electric and magnetic interactions (energy exchanges) are transferred by photons split off from electrons dropping to lower energy levels. Invisible Mr. Spock just told me so.

    • Rob Cairney
      Rob Cairney 10 days ago

      And it is only at that (quantum) level that it really makes sense. In this explanantory video there is a lot of assumed information such as ' impedance' that we all naturally assume is something that impedes the flow, but does it really? It's all a bit like the innaccuracies taught to trades people so they can do their jobs, without having to grapple with significant real and complex knowledge. Anyway, the full quantum level explanation requires a lot of assumptions as well, because it just does not add up in the classical macro world we have evolved to understand.

  • Paul Capri
    Paul Capri 26 days ago

    Very interesting and also difficult for this layperson to understand. I think part of what makes it hard to understand is the fact that we do not experience an 'electric shock' outside of the wire but only when e come in contact with the wire itself. I suspect the explanation of this will involve Amperage.

  • Randall Parker
    Randall Parker 5 months ago +644

    I'm 66 years old. As a child, we lived near large transmission lines in a rural area of CA. They passed over one of our pastures. We had a small water pump shed near the base of one of the towers. I "helped" my dad bury the power wires to the pump shed, 400 ft. from our barn/shop when he was installing a new pump. My dad used pipe strapping tape to mount some fluorescent tubes inside and outside of the shed. Everynight the lights were always on and I asked him why. He took me out to the shed, and asked me if I felt anyything... I realized that the hairs on my arms felt tingly, and I felt something in my ears. He explained about how such high voltage cables as above "induce" a magnetic field way around the big cables, that's what gives me the feelings, and what makes the tubes glow like they were wired to something. That had to have been 1960 /61- as I had just started 1st grade. He drew some sketches to show how "he thought" it worked. He gave me a basic electricity book and quizzed me every once in awhile. His sketches looked just like your graphics. I guess my dad WAS a lot smarter when I was younger. LOL

    • m s
      m s Day ago

      @MarkoZBogdańca The tube itself is the 'loop'

    • makrisj
      makrisj 19 days ago

      @Daniel Kohwalter In my place there was some1 that coupled many turns on a fence to the neighboring AM antenna. They tuned the loop with variable capacitors and they led the power via a T-match to the heating element of the boiler, having hot water during the winter.
      Up to the moment measurements revealed that the lobe of the antenna has changed radically. All sides of the antenna interact to create directivity, thanks to the conservation of energy. So if you "steal" some of the energy the antenna lobe goes on a different direction.
      Engineers went into the problem, took ferrite loops around the antenna field, found the... "leak", fined the culpit.

    • makrisj
      makrisj 19 days ago

      @graham121150 electrons are being ripped apart from the mercury atom (the vapor inside the tube) and then recombine with another neighboring ion to reform the mercury atom. The electron that recombines with the atom loses energy in the form of UV photon. That photon interacts with the phosphor on the glass of the tube (the white stuff). Visible light is being emitted.
      It could either have an E-field between the ends of the tube, or an E-field between any points in the space surrounding it - if the field is strong enough, electrons could be ripped, recombined, the fluorescent tube will glow.

    • makrisj
      makrisj 19 days ago

      @MarkoZBogdańca If there were high voltage lines, then they had to be AC. Maxwell goes: If your E field across a conductor is changing over time, there is magnetic coupling that induces *reverse phase* voltages to that conductor's edges or surfaces.

  • Nicholas Taylor
    Nicholas Taylor Month ago +2

    Isnt a simpler (and more informative) way to explain this concept to just say that if you have perfectly conducting wires laid perfectly parallel to eachother laid out to infinity then you can transmit 100% of power between them even if they never meet to complete a circuit. You only reach that 100% as you reach infinite length but the length increases at the speed of light. Its like a very abstract antenna or transformer.

  • Daniel Zubovic
    Daniel Zubovic 28 days ago +2

    What's awesome about this explanation is the implications of wireless charging and power delivery. It's only a matter of time before we figure out how to have energy just flow through the air, without the need of all these wires everywhere. The future is wireless

    • LuckyDrD
      LuckyDrD 18 days ago

      Nikola Tesla was working on that.

    • Herner Weisenberg
      Herner Weisenberg 26 days ago +1

      The claims of this video are misleading. Ask yourself this: if the energy is not conducted in the wire but by the field, how comes your wires will melt if you bridge your breakers and draw too much power through them? ;D

    • Don McNevin
      Don McNevin 26 days ago +1

      If they can solve for telecommunications, navigation and radar maybe. But you also can't just create a huge voltage potential floating around for someone's kite to stumble upon. That's kind of mother nature's job.

  • Ric P
    Ric P 18 days ago +5

    hey, what are good books you would recommend for a novice trying to learn about electricity the 'correct' way? - Thanks for the great video

  • Xavier Cebeira
    Xavier Cebeira 23 days ago

    So I can understand why cables would be magnetically shielded to avoid interference, however would this not also drastically increase the impedance?

  • Lone Kanne-Hansen
    Lone Kanne-Hansen 6 months ago +694

    "Now that you understand how electrical energy flows..."
    Bold assumption, sir! I'm still wrapping my head around this lol

    • foxopossum
      foxopossum 2 months ago

      Lol same. I feel like I need to watch again but take notes 📝

    • Terry Plank
      Terry Plank 3 months ago

      @Neo the Riot Your not stupid he is selling BS wrapped in facts

    • Colin Brown
      Colin Brown 3 months ago

      Thats cause its deceptive

    • Michael H
      Michael H 4 months ago

      It’s interesting but useless to me. Shame really, I want to understand, then remind myself it actually doesn’t matter if I do or don’t.

    • Lukas Wögerbauer
      Lukas Wögerbauer 5 months ago

      @Neo the Riot
      Think of the electromagnetic field as a very narrow tube around the wire. Only with very high voltage this electromagnetic field will become strong enough that you have to keep a physical distance from the wire. The field is not as strong or wide as shown in the sketch.

  • sickleandsuckle
    sickleandsuckle 6 days ago

    I remember learning about the Poynting vector in undergrad but never knew its significance. Now I do!

  • Jorge Almeida
    Jorge Almeida 22 hours ago

    I have a question... if the bulb would take 1/c seconds to light up, then the magnetic field would be traveling from the batery to the bulb faster than light wouldn't it? is that even possible?

  • Kenneth Shafer
    Kenneth Shafer 26 days ago +8

    So here's my question: What happens when you add another switch way out equidistant from the bulb and the battery? So that the information "the circuit is complete" has a necessary lightspeed delay?

    • J Modified
      J Modified 26 days ago

      The initial induced current at the bulb will be exactly identical whether the second switch is on or off, until distance_between_switches / c. That induced current does not require a complete circuit.

  • patrick sohacki
    patrick sohacki Month ago +2

    I discovered this myself when I was playing with one of those lightning plasma balls and my Xbox 360 would turn off and on/ open its disc door depending on my finesse. no way I'm the only one

  • Geologian
    Geologian 6 months ago +180

    So, viewing the energy transfer as field and flux makes a lot of sense, but how does resistance actually draw power out of the field? Does putting an additional resistor in a circuit warp the field? What about resistance in the line? Really cool stuff, I think you're gunna need a follow up video that deals with the details and minutia.

    • 3dw3dw
      3dw3dw 6 months ago +1

      When we think in terms of dimensions specify the measurement of a height dimension from a width, or depth dimension. We can easily recognize that we have 3 spacial dimensions to work with. But what if we have more? What if electrons occupy or even comprise another spacial dimension. One that also contains the FIELD or magnetism. Suppose electrons are in a different spacial dimension than the nucleus of it's atom and there is a force that ties them together. We may even find that the spacial dimension itself is the electron, or more to the point the only electron. I know what I am saying is tough to agree with, especially we we've accepted that we know so much, but once upon a time we thought we knew the earth was flat and we were willing to burn people alive for suggesting otherwise. Please do consider the spacial dimension where the field resides as integral to the universe and yet independent of height width and length as they are independent of one another.

    • kashu
      kashu 6 months ago

      @FloPhysics the poynting vector will be pointing inwards; resistive wires draw in power to maintain the work being done on the charges to keep the same current while going through the resistive material

    • kashu
      kashu 6 months ago

      resistors draw power when current flows through them, this current is due to an electric field through the resistors and it produces a magnetic field around the resistor boundary. we thus have electric and magnetic fields just outside the resistor aligned such that the poynting vector points inwards and so there is an overall flux contributing to the work done on moving charges internally, generating heat!

    • Cheshire
      Cheshire 6 months ago

      The resistor slows electrons down (through impurities in the conductor material among other things). This is also a form of acceleration and thus creates an electromagnetic field. This field cancels out part the existing field around the wire and thus saps off some of the energy flow.

    • Robert
      Robert 6 months ago +1

      The electric and magnetic fields associated with the EM wave excited electrons that then lose that energy through collisions with atoms in the conductor. So the current saps energy away from the poynting vector. If you notice all the poynting vector lines converge at the light bulp, that is where the currents effective sap that energy away from the EM fields and transfer it to heat

  • Richard Mathews
    Richard Mathews 25 days ago +5

    This reminds me of a problem on transmission lines posed by one of my physics professors. I’m not sure which one, but I think it was Richard Feynman. It was expressed differently, but I think it comes down to the same thing.
    To make my point even stronger, I’m going to make the lines be half a lightyear long instead of a light-second. The battery is big enough to provide power for years.
    The video is absolutely correct about energy flow being dictated by E × B, but the conclusion that the light bulb immediately lights up is wrong. The short explanation is that for a year the circuit is equivalent to having thousands of ohms of resistance in series with the bulb. With any realistic combination of battery and bulb, that will not allow enough current to light the bulb.
    The sets of wires act as two transmission lines running to each side. When the switch is first closed, almost all of the energy flow will be along each transmission line. The wavefront of that energy will move at almost the speed of light. There will be almost no energy flowing through the bulb. We can determine this quantitatively as follows.
    Each transmission line has a characteristic impedance determined by the ratio of the thickness of the conductors to the distance between them. With conductors that are 1 mm thick and separated by 1 m, this is an impedance on the order of around 1000 Ω.
    For the first six months, energy flows down the two transmission lines. How the lines are terminated doesn’t matter during that period. Until the wavefront reaches the end of the line, it might as well be an infinite transmission line. If there is a matching resistor at the end, it acts like an infinite transmission line forever. An infinite transmission line acts exactly the same as if it were replaced by just a resistor. The energy flowing into the transmission line is exactly the same amount of energy as the equivalent resistor would turn into heat. The circuit is equivalent to having a battery, a bulb, and two 1000 Ω resistors in series. There is no light with so much resistance.
    If the lines are terminated with a short (which is what this video posits) or an open, there will be a reflection wave that will take another six months to reach the bulb. If there is an open, B in the reflection wave cancels B in the original wave; so E × B is zero, producing no light. If there is a short, current will flow, B will be non-zero, and the bulb will illuminate a year after closing the switch (the reflections will actually go back and forth for a while, so it may actually take several years to reach a steady state).
    How do we know this? Once the round-trip transmission delay passes, the length of the transmission line is irrelevant (neglecting resistive losses). It will behave exactly the same as it would if the short or open were at the end of a light-second transmission line or a one-meter transmission line, and we know what happens in the latter case from experience.
    During the round-trip transmission delay-something like 2000 Ω of serial resistance and no light. After the transmission delay, negligible serial resistance thus giving light.
    Here is a final though experiment that maybe makes the importance of the transmission line clear. What happens if you place the switch at the end of the line, half a lightyear from the bulb? Can closing the switch instantly make the lightbulb light up? What does E × B look like before and after you close the switch?

  • Dan Dwyer
    Dan Dwyer Month ago

    Great video. Question what makes up the energy field? Another words what kind of particles? I'm sure the answer has something to do with the energy field being the product of the electrical and magnetic fields

  • Jarno Langenbach
    Jarno Langenbach Month ago +2

    I was once taught in school that there are always electrons in the entire wire, this way if one electron pushes on one side, another electron gets pushed out the other side. This way a light would turn on almost instantly (not instantly because it takes some time for the electrons to move). Would this explain the 1/c answer of the question if the light would turn on at any current?

    • Morbad th' Worst
      Morbad th' Worst Month ago +1

      @Box Fox That's a nonsensical question. You may as well be asking "what if a duck wasn't a duck"? The speed of light in a vacuum is a universal constant; it doesn't really have anything to do with light specifically...light itself often moves far slower than *c*. Anything faster than *c* would violate general relativity. So far, nothing has been observed to do this...our tests keep getting better and we keep demonstrating that the law holds. Nothing needs to move faster than *c* to explain any phenomena actually observed to exist.

    • Box Fox
      Box Fox Month ago +2

      Man doesn't know all forms of energy. Light may not be the fastest energy. Only the one man knows of.

    • Box Fox
      Box Fox Month ago +2

      @Morbad th' Worst what if light isn't the fastest form of energy?

    • Morbad th' Worst
      Morbad th' Worst Month ago +2

      No, because that would imply you were transmitting energy faster than the speed of light, which is impossible. Even if you had a completely inelastic/infinitely rigid rod that was one light-second long, it would still take one light second for the opposite end to start moving if you pushed the other end. Those electrons at the far end of the wire in this example are the same way; they take at least a second to start moving. The reason the example would work is that ones in and around the bulb are much closer.

  • John de Wit-Zondag

    I'd say "none of the above" because the electrons that are in the wire (right next to the bulb) are pulled through the bulb by the difference between plus and minus. So immediately, no delay.

  • Matteo L.
    Matteo L. 5 months ago +241

    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.

    • Ferretcatcher
      Ferretcatcher 5 months ago

      Poynting vector is a redundant term; all physicists know that vectors point!

    • Alex Maltais
      Alex Maltais 5 months ago +2

      I don't think this video is appropriate for a university course.

    • Randy Pittman
      Randy Pittman 5 months ago +1

      Once again I remember why I nearly failed E&M in college.

    • Eugene Bird
      Eugene Bird 5 months ago +4

      The vector isn’t a real thing, it’s just a mathematical device.

    • marvinalbert
      marvinalbert 5 months ago +1

      @Isaac Groen Actually arrow directions are pretty wrong, they're much more parallel to the wires.

  • Matthew Wilson
    Matthew Wilson 23 days ago

    Love this. Could you gain further proof through the thought exercise of a field around a wire traveling at a different rate (or the overall impedance of a wire being lower) if the wire was in the vacuum of space vs the wire being in Earth's atmosphere? I know you mentioned the Atlantic telegraph cable. I am surmising that the the traveling electromagnetic field must interact with any substance surrounding the wire (to a limited distance) in some way.

    • Matthew Wilson
      Matthew Wilson 21 day ago

      @J Modified Thanks very much. I'm a biologist trying to make materials for a welding class and want to make sure I am not just reinforcing the incomplete ideas I was taught.

    • J Modified
      J Modified 23 days ago

      Sure, this is a common experiment done by EE students in an EM fields lab course - verifying that signal speed depends on the medium surrounding the wire, such as insulation vs no insulation. I did it myself when I was an EE student 30 years ago.

  • Robert Brown
    Robert Brown 20 days ago +10

    Existence of the Poynting vector is not a done deal. Other equations for the electromagnetic wave exist. The big physics people (post Einstein) are not interested in the finer points of electomagnetics. Maxwell's equations were written by Oliver Heaviside who was despised by the science establishment, and also developed complex numbers. So the answer is none of the above and depends on the velocity factor of the wires.

    • Robert Brown
      Robert Brown 7 days ago

      @Commenter Of Truth I realise anyone that contradicts the doctrine gets discredited yes. Heaviside revised the mathematics of someone 'high ranking', and despite his elegant solutions being used by millions of engineers, was despised by the 'scientific community' and died poor and (nearly) forgotten.
      Investigate 'magnetic monopoles' and 'displacement current' for two inserted beliefs.

    • Commenter Of Truth
      Commenter Of Truth 7 days ago

      you do realize the science community hates people who would argue against their firm beliefs, right? maybe not all of them, but the high ups will denounce the person making the claims as insane. they will provide a believable aregument against this theory. and it will be a correct argument, if hes an actual high up rankin feller. but its only correct because he would be explaining exactly the same thing, but the process would be based on inserted beliefs.

  • Antonio Soares
    Antonio Soares Month ago +2

    If that's the case, that the electricity actually flows through the electromagnetic waves why don't we get any electric chock when touching an insulated cable ? This is interesting subjet 👍🏼

    • Bajan Energy
      Bajan Energy Month ago +2

      Depending on the thickness and type of insulation material used in reference to the power on the side, a spark could even happen if the load greatly outweighs the resistance of the insulation, burn the cable and essentially give you full contact.

  • dan428
    dan428 Day ago

    I usually understand all these science videos pretty well but this one pretty much boggled my brain to a mush.

  • Dalnore
    Dalnore 6 months ago +312

    That's a great video about power transmission! I remember being surprised by that in the university.
    I really don't like the 1/c answer, though. While it's technically true that there will be some voltage on the lightbulb after 1/c simply because the electromagnetic fields generated around the wire will reach it, but it has nothing to do with them being connected by wires. In the same way, you can say that turning on this battery will "turn on" every single lightbulb on the planet. This is also technically true, because there will be some field generated by the battery in the entire space, and it will induce some voltage everywhere. Although its value will be negligibly small, as the magnitude of fields around the wire quickly drop with the distance from it. Only after 1 second, the proper connection through the electromagnetic mode of the wire will be established.
    If you replace the wire with an ideal coaxial cable (which doesn't let any EM fields outside the inner space between the two conductors), the answer will always be 1 second, as there's no leakage and thus no way for the lightbulb to receive the EM energy from outside the incoming cable.

    • Fourth Root
      Fourth Root 27 days ago +1

      @Antonio Monzon Derek didn't have meters in the numerator. 1/c is not the same as 1m/c.

    • Antonio Monzon
      Antonio Monzon 27 days ago

      @Fourth Root [m]/[(m/s)]=s
      No unit problem there.

    • Fourth Root
      Fourth Root 5 months ago

      @wbeaty "1/ c" is not a number.

    • Fourth Root
      Fourth Root 5 months ago

      @Dalnore 1 m / c would be correct. But that's not what he wrote or said. He said "1 / c seconds" which is completely different and totally wrong.

    • wbeaty
      wbeaty 5 months ago

      @Fourth Root Agreed! Dereck was using expert-speak here, perhaps appropriate for talking with physicists. But he's supposed to be informing beginners, not speaking jargon with fellow experts. It's only 3.3nS or "1/c" in seconds, because of the 1M gap, and this improper use of units keeps the fact hidden.

  • Raúl Moreno
    Raúl Moreno 3 days ago

    there is a theory that says electrons are small black holes, but also charged, they are also a wave, but its evident what are they really : worm holes one side is charge negative and the other positive (still they are waves) they have also electromigration (they can move matter from one point to another in integrated circuits), thank you Veritasium :)

  • Ryan Stallard
    Ryan Stallard 26 days ago +1

    Everything makes sense up to the claim at the end. If the wires carry the field, and we know that information can't go faster than light, then why wouldn't it take a second for the bulb to turn on? Otherwise, it seems the wires aren't necessary (since they don't directly connect the light bulb and the battery), yet we know they are.

    • Aryan Taywade
      Aryan Taywade 24 days ago

      Wait I’m confused, don’t u need the wires bc they have the electrons that get the initial push in terms of energy (voltage) in order to transfer that same energy into other forms.

  • Volodymyr Opanasiuk
    Volodymyr Opanasiuk 23 hours ago

    What if you replace this with a perfectly rigid stick 1 light second long. Push it from one end. How long will it take to feel a response from the other end?

  • Ra
    Ra 29 days ago +15

    An outstanding question I think which would have completed this video is how do batteries store this electromagnetic energy 🧐

    • Commenter Of Truth
      Commenter Of Truth 7 days ago

      ​@Ra photons are not fields. photons are made up for believed equations. they are just fields.

    • Zhugna Chaz
      Zhugna Chaz 15 days ago

      @Ra I think Doctor Donut already answered your question. If you charge your phone you are basically moving ions from the cathode to the anode, which 'costs' energy. When discharging your phone the ions move from anode to cathode and 'release' energy (simplified and you have to switch the name anode and cathode for charging and discharging, but that would be confusing here). So you are indeed storing energy as potential chemical energy.
      To your question how photons can be stored as chemical energy:
      Look at photosynthesis, that's storing sunlight in form of chemical bonds in action. A very simple explanation would be that the photon excites the atom or electron and in this excited state it can form a stable bond that is at a higher energy level. If you break that bond you release that energy, ike burning wood or eating carbohydrates.

    • Ra
      Ra 26 days ago

      @TheSoleSoul 13579 Electromagnetic energy stored as potential chemical energy … hmmm 🧐 Still confused because the force carrier particle to electromagnetism is the photon. Not sure how photons can be stored as “Chemical energy.” Still waiting on Doctor Donut’s answer. I think he is saying electromagnetism sparks the potential chemical reaction within the battery’s content reactants. Thanks though for putting up with my ignorance 😋 🤦

    • Ra
      Ra 26 days ago

      @Doctor Donut oh so, the electromagnetic energy sent to my phone is sparking a chemical reaction within battery’s reactants? 😮

    • TheSoleSoul 13579
      TheSoleSoul 13579 26 days ago +1

      @Ra Any energy can can be transformed into any other energy or even hypothetically matter. The energy needed for the electromagnetic fields could be stored as any other energy and in this case it would be potential chemical energy.

  • Nisco Racing
    Nisco Racing 6 months ago +226

    We need at least a mini series about this.
    This is so insane that i still don't understand.

    • Nisco Racing
      Nisco Racing 6 months ago +1

      Trending #1 maybe we will get the mini-series 🥳

    • fenhen
      fenhen 6 months ago +1

      @Matt Murphy To some extent.
      But kids come into the world knowing nothing and are still able to learn without any prior knowledge on topics.

    • Quinton Wilson
      Quinton Wilson 6 months ago

      Derek is tremendously horrific at explaining concepts.

    • au7WeeNg
      au7WeeNg 6 months ago +1

      @Matt Murphy I think this is not that far off from what I said, moreso as one can think of a pair of antennas (a station's and a radio's) as forming a tiny capacitor. and here, presumably with 1 lightsecond of wire on either side, even being 1m apart, the capacitance will be large for the bulb to at the very minimum light up briefly...
      what I find unintuitive is that nothing apparently happens after 1 second (I think it's even slower in, say, copper.) surely something must happen when it sees that the two wires that form the arm, are connected at the end. because, to me, the very thing the problem derives its "piquancy" from is that with those lengths, the process of the circuit's finding its DC operating point (think of the arms as transmission lines - but even ignoring the parasitics, surely there is something that propagates only at c) happens in human time, but he stops right after declaring that the bulb goes on.

    • Poutine Au Syrop d'érable
      Poutine Au Syrop d'érable 6 months ago +1

      @fenhen Good job. Still, it's much harder to explain things without some amount of knowledge to use as a base.
      The physics required to understand this video is U0 stuff. It's done before university and, at the level at how he's explaining it, that stuff that you can learn by yourself easily if you passed high school knowledge.
      His channel covers more specific things than an actual education of the basics. Doing a mini series on this explanation would be teaching you that kind of stuff would not be the kind of content he's making.
      Youre better of just fooflinf the basics yourself if you need and want to

  • swicked
    swicked 20 days ago +1

    Flowing electrons create a magnetic field around them and magnetic fields cause electrons to flow. It's like how mass can't exist without gravity and gravity can't exist without mass. What seems like two different things is one thing.
    Case in point(s): That's why electric induction motors, ones that take in flowing electrons to harness their magnetic fields to generate mechanical energy, are also electric generators, ones that can take in mechanical energy to harness magnetic fields to generate flowing electrons. You can have breaks in the wires between power plants and your home be bridged by inductors that allow the magnetic fields generated by one side to create flowing electrons in the other. The undersea cable's potential was getting drained due to the magnetic fields inducting flowing electrons in the conductive outer shell of the cable... electrons that would then be grounded out in the water. Electromagnetic Pulses are destructive to electronics because the high-powered magnetic field causes electrons to flow in anything conductive that the EMP interacts with. The EMP itself is created by a lot of electrons flowing at once.
    This aspect of electricity isn't that complicated, really. You just need to stop seeing flowing electrons and their magnetic fields as two different things.

  • Roi Baer
    Roi Baer 5 days ago

    Maxwell showed that the electric current is composed, in addition to the rate of particle flow, also to the rate of change of electric field (he called it the displacement current). You could discuss this. It's probably relevant...

  • Ryan L
    Ryan L 11 days ago +2

    Does this have implications for the accepted constancy of "speed of light" and how long light from distant stars takes to reach us? Could it be that the light (EM energy after all) from distant stars is with us instanteously or at least quicker than is supposed? A vacuum (Such as Space, for example) is an insulator, and light is EM, so... but yeah. There's something about all this that seems to encroach into the realms of Observer effect and will. I confess My inadequately educated mind cannot keep up with my imagination, and leaves me feeling like the understanding of these things is only *just* out of reach, but it's great to think about.

    • Cheesepuff8
      Cheesepuff8 9 days ago

      I think it’s a definite thing that photons take time to reach our eyes from where they came from

  • Scott Horton
    Scott Horton Month ago +34

    So if we consider that the wires are really just antennas that allow the EMF's to be focused and contained, we begin to understand why Tesla believed he could transmit power wirelessly.

    • chistine lane
      chistine lane 18 days ago

      What do you guys all think radio is?

    • operatorblack
      operatorblack 28 days ago

      This is exactly where my brain when when I started processing this video

    • Stephen Church
      Stephen Church 29 days ago +15

      Tesla knew it could be done when he proposed it because Maxwell had proven the math and Crooks and Lodge had proven it experimentally. This isn't meant to diminish the genius of tesla because he absolutely was a genius inventor but it's important to understand scientific discovery and innovation as a constant building on the work of predecessors.

    • Johnmichael Quinlan
      Johnmichael Quinlan 29 days ago +6

      he didn't just believe it he proved it at the Royal Academy in a live lecture. They recently repeated the exact experiment you can find it on their youtube page.

  • nish
    nish 6 months ago +107

    Being an electrical engineer this topic still confuses me, god knows how i even passed the subject of Field Theory

    • Joe Finucane
      Joe Finucane 2 months ago

      @Peter Kosen Please see "Flat Earth: the history of an idea." Not very interesting, except for the unpleasant but hilarious story of Alfred Russell Wallace and the flat-earther. Poor Wallace!

    • Peter Kosen
      Peter Kosen 6 months ago +1

      @Marothi Kalushi Okay. But, as I said: My test is to challenge them on their willingness to think through a simple and definitive observation.

    • Marothi Kalushi
      Marothi Kalushi 6 months ago

      @Peter Kosen I'm not disputing that. I'm just saying you can't just dismiss their case without atleast looking at their case. As absurd as it is WHEN you look at the evidence.

  • Daniel
    Daniel 17 days ago +3

    There’s a great book called “There Are No Electrons” by Kenn Amdahl that explains these concepts and more in hilarious and intriguing ways.
    If there’s one thing you can take from this, it’s that electricity is not electrons moving like water through a pipe.

  • FZ750
    FZ750 14 days ago

    My dad was an aircraft electrician working on Boeing large crafts. When I was a child he tried to explain this to me he knew. He periodically tried again. My challenge was to understand the electron transfer theory given in school. Yet with transformer theory we know about the magnetic flow around wires. I needed this video to remind me of and Clarify how power actually flows. Electro magnetic flow around the wire interesting. Just for information. I've used an emf app to measure radio wave emissions from house hold appliances. I've found items that produce red hot elements emit high electro magnetic energy such as your stove, oven, toaster. I'm beginning to believe that there is a relationship between dna chain and the energy released. The DNA can be manipulated by the electro magnetic waves thus causing cancer or many other not fully diagnosed health issues. I would encourage one to research stats on breast cancers. I feel that the risk is while cooking, an exposed body portion being closer to the red hot stove is highly exposed. In the same manner the electro magnetic energy can be controlled by on and off using a frequency generator that turns the power on and off thousands of times per second. That controlled on/off energy can be used to treat health issues. In fact Dr. Raymond Rife investigated this and proved successful at curing cancers. The pharmaceutical industry from my understanding pressured Dr. Rife to stop he was then up against mountains of power. He did die of a heart attack. Yet now there are companies offering the device called Rife machine for public purchases. I just want to make sure people know and that possibly the medical industry may take interest in new more effective less invasive treatments. The technology is there.

  • Rusty yB
    Rusty yB 7 days ago

    While an EM field exists around the wires, due to electron flow, the wires carry energy. Any inductor stores energy, but the electrons must keep flowing to support the EM field. Trying to cut off the electron flow will force the EM field to essentially expend itself in a traumatic way unless an outlet for the energy is provided.

  • Davids Gaisevskis
    Davids Gaisevskis 22 days ago

    Two questions
    1) if the wires were a lightyear long, would the light come on immediately too as opposed to one year of waiting?
    2) if the electric meter was placed one light year away, how much of electricity consumption would it register?

    • Fattah Pras
      Fattah Pras 21 day ago

      watch his newest video for answer

  • number 33
    number 33 6 months ago +128

    It's pretty easy to test this. Just take a 100m length of 50 Ohm coax cable arranged in a big loop with the ends 1m apart, connect a 50 Ohm pulse generator to one end and a 50 Ohm resistor across the other end. Use an oscilloscope with two matched probes to see how long it takes for the voltage to arrive at the resistor. If it makes you happier you can put an LED in series with the resistor and cal it a light bulb. The result will be about 0.5 microseconds and not 3 nanoseconds.
    Of course I know I'm talking to myself, there's no way Veritasium can read 30,000 comments.

    • Aditya
      Aditya 15 days ago

      Derek probably did read your comment

    • George Hnatiuk
      George Hnatiuk 5 months ago

      @Coco Sloan time = distance/c so yes, 1 second = 300 000km/(300 000km/sec)

    • Coco Sloan
      Coco Sloan 5 months ago

      @George Hnatiuk So if the distance between battery and lightbulb is 300 000 km only than it would take 1s for the lightbulb to shine ? Is your ping lower near your router ? Check it !

    • George Hnatiuk
      George Hnatiuk 5 months ago

      @Coco Sloan that is not what is going on here. There is no faster than light energy transfer occurring or suggested. Veritasium is claiming that the primary path for energy transfer is not along the 300 000km wire but in the 1 meter air gap from the battery to the bulb. Yes there is a slight coupling there but it is INSIGNIFICANT for the dominant transfer of energy occurs much later in time than 1m/c along the wires.

    • Coco Sloan
      Coco Sloan 5 months ago

      But OFC he's wrong. Its a comment-bait Sir . He's example suggest that distance of 300 000 km can be crossed over faster than light . Why ? Because the electromagnetic field is already there ? So there's something faster than light ? Yeah right . Only stupid thought is faster than light !

  • DrGrandpa
    DrGrandpa Month ago

    Question: Would a superconducting plate between the battery and light bulb--with wires going through the plate--block the field from traveling between the two?

    • -
      - Month ago

      I don’t think so; super conductors heavily reflect magnetic and electric waves directly, but not Poynting vector itself. Since I’m a circuit, electric fields can be visualized as going along the wire, and magnetic field is immediately around it, then EM waves thru a circuit would not be reflected by the superconductor, although if large enough, might interfere with the performance of the circuit

  • Mark Brouhard
    Mark Brouhard 29 days ago

    So based on this understanding, I presume that conductor ampacity ratings stem from how the EM fields around the conductor create induction heating within the conductor, instead of electrons inside the conductor creating the heat. If this is true, then what happens if we use a theoretical conductor that possesses electrical conductivity comparable to copper while simultaneously being immune to induction heating?

    • J Modified
      J Modified 29 days ago

      When an electron collides with an atom in a wire, the field energy that was associated with its moving charge is transferred to that atom and ends up as heat. So for a wire with resistance (not a superconductor) there is a continuous flow of field energy into the wire from around it. This is resistive heating. There is no inductance involved. Inductive heating is just indirect resistive heating anyway - induced currents in something with resistance.

  • poweralpha2011
    poweralpha2011 18 days ago

    Even before starting the video I knew it was going to be "D" but I was wrong, it was D because you activated the field, not the flow, that's what made it start instantly.

  • Mareinna Shaw
    Mareinna Shaw 10 days ago

    So. What's your thoughts on the electric universe theory by thunderbolts project? I've been following them for years and it reframes so much of what we know... I feel like a lot of standard science these days is analogous to the issue that very few people know how electricity in a simple light bulb circuit works.

  • giovannipu
    giovannipu 6 months ago +379

    Hello Derek, a physics professor here. I love your videos and I subscribe to your channel - in all honestly, I consider it the best example of public communication of physics and science I have ever met - I am not exaggerating. I actually used some of your videos when teaching to my students. However, you did not convince me with this one - not that I love you any less for this. I have similar objections to some that have been made by others here. The explanations of the fields, and the Poynting vector are gorgeous and very instructive, by the way. But I have tried to explicitly calculate the flux of the Poynting vector on the bulb, and I find it to be quantitatively a small effect (quickly dropping with distance of the bulb). Yes, there is *some* disturbance at the bulb, but I think it is a bit misleading to just say that it "turns on". I suggest to have this checked by other people - I would be very curious to see a follow-up on this. You are actually tempting me to try this out in my own lab.
    Anyway, even if it turned out you had slipped on this one, that does not change my opinion about your work. Physics is non-trivial, and what really matters is to have the right scientific approach to problems, not to never ever make a mistake (even Galileo did) - eventually things sort themselves out if you follow the right track.

    • Ted Rees
      Ted Rees 2 months ago

      @giovannipu But the initial current will not reach the bulb until the voltage at the bulb rises due after the transmission time delay.

    • Ted Rees
      Ted Rees 2 months ago

      @SpeedFlap All wire has inductance and capacitance. They are both finite element models for the em fields.

    • Ted Rees
      Ted Rees 2 months ago

      This video is misleading. Just because the Poynting vector points in the direction of energy flow, it doesn't mean that it causes the energy flow. The conclusion is also dead wrong. Anyone working in a lab with a fast scope can observe the time it takes for a signal to flow down a wire. You don't need a stupid impossible single wire 2 light seconds long. All you need is a few feet of wire on a bench, and a signal generator with a fast pulse generator. Sync the scope from the generator, and probe along the wire. you will see that the pulse is delayed a bit more than 1 nano second per foot. Putting the end of the wire next to the signal generator doesn't make the time delay go towards zero.
      By the way, for fast signals, the wire should be a transmission line, that consists of another return line spaced closely to the signal line, that is grounded. It could be a twin pair, or a twisted pair, or a coax with carefully crafted test points. The load should be a resistance equal to the characteristic impedance of the transmission line. Otherwise, you get the signal bouncing from the end of the line and traveling back to the generator.

    • Ersin Emre
      Ersin Emre 4 months ago

      Professor all your calculations are inaccurate because of we don't know how fast the space is expanding. He is good in this video because İ always thought what the hell a lot electrons coming from.

    • Amani
      Amani 4 months ago

      2022 is your year, 📣
      _"Make sure the money works for you,"_
      *🔍 BLACKPINK Lisa - MONEY* 🎵
      : Hip-Hop 🎵to get energy

  • Jimmy Brannan
    Jimmy Brannan 5 days ago

    Like many of your viewers, they listen and believe your videos without giving it a second thought. But like you suggested from another video I have given this some thought. If the electrons aren't traveling through the wires, like science has suggested for years, why do the wires get hot when too much current is sent though the wires? I guess in the years to come another idea will come along and this idea will fall to the wayside and we might know.

  • Briz KT
    Briz KT 27 days ago +2

    I'm a Master Electrician who has an EE degree. I very much understand the science, but there is a disconnect between the explained science in this video and practical application.
    The physical mass of the conductor has to play a part. If it were strictly true that current flows around the conductor rather than through it, why aren't conductors hollow? Imagine how much copper could be saved by running a 1/2 copper pipe instead of running 500 kcmil stranded wire. Some may say, "look! You said stranded wire," like the space between the strands makes a difference. Strands for this kind of wire is not for conductivity, but to be able to bend it. I think a simple experiment can at least shed more substantial light. The control is a standard 500 kcmil wire with 37 strands with a resistance of .021 Ohms per 1000 feet. Experiment conductor 1, is a 1/2 copper pipe. Experiment conductor 2, use 37 strands that are the same size of 500 kcmil wire, but loosely separated. My solid hypothesis is the standard 500 kcmil will conduct the best, which still begs the question of the validity of the claim that current flows "around" conductors" as opposed to through. I do not disagree that how we observe the flow of current through a conductor is detecting the magnetic field around the conductor. What I think is a more likely explaination is that the field emanates from each and every copper atom.
    Another experiment is taking a long conductor and test the shift of electrons with a strong enough voltage applied to one end. With a scale sensitive enough, I would like to see if the end with a strong positive voltage applied will weigh more than the side with the negative voltage. This would indicate a shift of electrons from one end of the mass to the other. Even if I'm wrong, such an experiment would still be fascinating.

    • Commenter Of Truth
      Commenter Of Truth 7 days ago

      I see it as fields existing where they will exist. and if theres a hollow wire, the entirety of the field will be effected in some way because the way it which it is flowing energy. it is producing exactly the same field if there is no physical altercation to its energy production. but since the field exists from a different environment, it will be different, some how some way. maybe not even percievable, unless the actual energy or other aspects are changed, but if its JUST made hollow, with no alterations to the energy its getting, I dont see it altering how fields are produced, atleast, the amount of energy or the size of the energy would be the same quantity.

    • J Modified
      J Modified 27 days ago

      "If it were strictly true that current flows around the conductor rather than through it, why aren't conductors hollow"
      Current flows through the conductor only. Energy flows around it and not in it, or at least that is a reasonable way of looking at it.

  • Wolenv
    Wolenv Month ago +1

    A logical philosopher would simply say: Cables are reproducing the electro magnetic waves form the generator but the force carried exist outside just because there is less resistance with air.

  • Ted Bohrer
    Ted Bohrer 14 hours ago

    Semi-conductors seem to rely on electron (and hole) flow, not fields. Also, what is an ammeter measuring?

  • Honor4OP
    Honor4OP 6 months ago +118

    If physically possible, I would like to see a video in which a disturbance in the field interrupts the light from switching on/off regardless of a wire moving electrons. I believe it can serve as an amazing example of how the energy is stopped or negated through the air rather than through the wire (:

    • Marc Fruchtman
      Marc Fruchtman 6 months ago

      @Leon Buijs Hmm, probably you were taught about it but didn't internalize... When they talk about electric charges that is the electric field. When they talk about the electromagnetic wave that is the moving part that gets induced by the moving charge.
      You can have an electric charge (battery or capacitor)... that is static (not moving). When it is static there is no EM field.
      When the charges move (whether positive or negative) then the EM field is created.

    • Leon Buijs
      Leon Buijs 6 months ago

      @Marc Fruchtman The EM field is one thing. The electric field is the most overlooked part. I never even heard of it in physics class, found out only recently.

    • Amy G
      Amy G 6 months ago

      YES this is exactly what I was thinking the whole video

    • Marc Fruchtman
      Marc Fruchtman 6 months ago +6

      @Phillip Otey How much insulation do you need to stop an electromagnetic wave that extends into infinity? It's not possible. Instead, think of it this way... the energy of the EM Wave in the air or free space is inversely proportionate to the square of the distance, so, very very little energy is reaching the bulb 1 meter away thru the air. It is NOT enough to light the bulb. Veritasium is making a mistake.

    • Phillip Otey
      Phillip Otey 6 months ago +3

      You could add insulation between the wires and the conductive sphere.

  • David Yancey
    David Yancey 9 days ago

    Yes! I see the light!!! Wonderful subject, well demonstrated, and doesn't it feel like this has some even more profound realizations down the road. Thanks.

  • Jordan Warman
    Jordan Warman Month ago +5

    Thanks so much for this video. Question: If it’s the waves around the wires that transmit the energy, then, if you have a light bulb in a circuit, could you place a second bulb close to the first bulb, with no wires touching the second bulb’s contacts, and have the second bulb light up?

    • Charles Howard
      Charles Howard Month ago

      Like Uncle Fester

    • Georgi Georgiev
      Georgi Georgiev Month ago

      Jordan now you're thinking along the lines(puns intended) of Nikola Tesla, and him showing how electric fields work.

    • Justin James
      Justin James Month ago

      The second bulb would have to have an apparatus which directs the electric potential in the air in such a way that there is a voltage induced between the two conductors of the bulb. In either case, you could get a little potential but these fields tail off quickly from the conductor so you wouldn't get much. The best way to get some is to connect the light bulb to a coil close to the original conductor, essentially acting like a transformer. People have done this near power lines to steal energy from them.

    • Michael Gautreaux
      Michael Gautreaux Month ago

      It's a Tesla thing, honest!

    • J Modified
      J Modified Month ago +1

      You won't get much current with just a bulb and it will be for a very short time, without the long wires attached (they don't need to be part of the circuit).

  • Radar Tutorials
    Radar Tutorials 13 days ago +1

    I'm a little confused, so, if we were to have the ac generator and the light bulb at the furthest points, would it still be 1/c or would it take longer?

    • David Moore
      David Moore 10 days ago

      Longer. Speed = distance (metres) / time (second), so time=distance/speed.
      [Time for field to travel 1m from battery to bulb] = [distance between them] / [speed field moves at]
      [time for bulk to light (a little bit)] = 1(m) / [speed of light (m/s)]
      time to light = 1/c
      If they were at the furthest points, and the furthest points were say 600,000km apart, (as in the thought experiment in video), it would take 600,000km/300,000kms-1 == 2 seconds.

  • eb bay
    eb bay 6 days ago

    It reinforces the theory we all knew, that energy is with the electrons it is the movement of electrons that goves the fields and also transmit power. With AC the work done is always positive, while the fields are reversing . If you connect a polarised device to AC it will vibrate and not work correctly,since the effect of current one way is cancelled in the next half cycle, however what ever the direction of current power will always be positive, since this is due to the movement of electrons and not the flow.

  • Kamil Pekala
    Kamil Pekala 6 months ago +110

    Oh yes, please do an experiment in the Mojave desert! Also let's check a few more variations:
    1. arrange the circuit in a circle - that way the shortest path through space would be the diameter
    2. enclose stuff in a Faraday cage to block the fields from taking a shortcut and see if it lengthens the time to light up the bulb

    • MyNameIs
      MyNameIs 6 months ago

      WHAT IF the both wires go half the distance to the moon and back in the same direction ( not in the opposite directions as it is here)???

    • necron 1050
      necron 1050 6 months ago +2

      the faraday cage might not be possible it depends on the wave length of the EM weather it works or not. if it is possible it would be really interesting

  • tomctutor
    tomctutor 14 hours ago

    Electricity can be transferred from source to load without any wires at all!
    Well was that not exactly what Hertz showed in his infamous experiments ~1886.
    You may disagree and say that he proved veracity of Maxwell's EM theory, well he did as much.
    But he did manage to transmit electrical energy at c as he himself noted.
    Today we use waveguides and coax to transmit electrical energy (if you want to call it that) in the form of microwaves, there's probably such a device in your home kitchen!
    Purists might not call EM energy electricity but they are just being pedantic. 🔌📡🤔

  • Waldemar kamiński
    Waldemar kamiński 15 days ago +1

    Very funny!
    The drift speed of the electron is known to be 1/10mm/second. In the example: An electron "leaving" a battery 100m away will reach us after 28 hours. So, even if it "pushes" other electrons in the wire/cable. And there would be "friction" in the filament of the bulb would still not heat up and would not light up.
    This is knowledge from primary and secondary school that the current flows and it is not.

  • Edward Blair
    Edward Blair 22 days ago

    As someone who works with circuits on printed circuit boards, with lots of traces close together, this is not a concept I want to think too closely on. When I send a signal down one trace, how do I keep the field from sending energy down a different trace?
    I'm just the firmware engineer writing code to operate the circuit, not the electrical engineer laying out the circuit. I have to trust that they know what they are doing, so I can continue to think about pushing (or pulling?) electrons like normal people do.

  • Honey Singh
    Honey Singh 18 days ago +1

    Wow sir what a great explanation.
    Iam a 11th class student and I love physics.
    Actually this things should be teached to us in lower standards.

  • Sam Gralla
    Sam Gralla 6 months ago +249

    It's great to see the Poynting flow argument reaching such a large audience! I always cover this in my college E&M classes. But I have to say that the claim that the light bulb turns on right away is pretty misleading. Consider the case where the circuit is actually open -- somebody cut the wire 300km away. By causality, the light bulb's behavior is identical in both cases (closed and open circuit) for t

    • Lady Mercy
      Lady Mercy 6 months ago +1

      Yes.
      The wavefront intersect the light-bulb almost instantly. But the wavefront carries 0 energy, because the energy is the integral of power with respect to time. Their thought experiment only functions in this way in the specific instance when the amount of light being emitted is "none." And if they did integrate across time, then they'd have to contend with destructive interference coming in from the other side of the circuit. It becomes a problem of "how long does it take to build a square wave that resembles a DC current?" That number is obviously proportional to the length of the wire, regardless of what Poynting's hand mnemonic suggests. His mnemonic for helping him to remember which part of his body is on which side only indicates angle through space, not duration through time. It's an inappropriate usage of the information it was meant to convey. Bad science all around.
      But honestly, I'm just stoked that they decided to make a video pointing out the flaws of the fluid-through-pipes analogy that misconstrues electrical transient phenomena. That's a step forward, by my estimation

    • Urano
      Urano 6 months ago

      @GimpIsNuts dude I'm so glad you made this comment because I didn't catch that at the start of the video. I went back and it's at 12:30 where he reiterates what I said. So thank you.

    • Daniel Gould
      Daniel Gould 6 months ago +1

      This video is pure nonsense. All you have done with the Poynting vector fields is replaced one question (1) with another equivalent question (2):
      1. How long does it take for electrons to start moving through the light bulb?
      2. How long does it take for the Poynting field to "reach" the light bulb (in the sense that the integral of the Poynting field through a small bounding surface S around the light bulb, is nonzero)?
      Clearly, (2) depends on (1). If there are no electrons running through the light bulb, then there is constant magnetic field around the lightbulb and therefore the integral of the Poynting field across a surface S around the light bulb is zero, and the energy transfer rate is zero.
      You fallaciously assume that the Poynting field from battery to lightbulb can be established at the speed of light, which is why you reach the false conclusion that the light bulb turns on after a time of 1m/c. I also wonder if you are fallaciously thinking that the Poynting field transports energy at a "speed" of c? If you think about it, there is no such thing. There is just a rate of energy flow; it makes no sense to ask how fast it is moving unless you can identify a particular chunk of energy and see how long it takes move from A to B. But you can't do that.
      To get the correct answer, you need to apply your own logic from earlier in the video: the electric field within the wire can propagate around the circuit at a speed of at most c. Until there is an electric field across the bulb, there are no electrons flowing through it, the integral of the Poynting field is zero, and therefore energy transfer rate is zero.
      So the correct answer is "at least 1 second".

    • WeBeGood
      WeBeGood 6 months ago

      This is my take on it, really like your comment about someone cutting the wire 300km away.
      The energy may be flowing only 1 meter, but it took 300,000,000 meters for the E/M field to be established in the wires leading into and out of the light bulb. There is no E/M field in wires connected to the light. I'm using shielded wires so that the two long parallel wires don't create any electromagnetic interference with each other causing them to behave like a transformer

    • Colruyt Gaming
      Colruyt Gaming 6 months ago

      ye I was already questioning because of the part where he says the electrons move a bit , if it was supposedly turned on the reaction of electrons 300.000 km away moving a little bit should have happened faster than the speed of light which would break the law of physics

  • DAMIEN S
    DAMIEN S Month ago

    It is the WAVES that carry the "energy" and NOT the electrons! Here's a simple example: Think of a swimming pool that creates artificial waves with rotating paddles for indoor surfing. The paddles move back and forth like rows of a boat (and like the electrons do) but the waves created by those paddles always travel to the same direction until they hit the walls of the pool and bounce back. If the pool was miles long, those waves would carry the energy along its length in the same direction. The same thing happens inside and around electric cables. The electrons are the "paddles" that create the EM waves, and the EM waves carry the energy. This is an example of a PARTICLE, creating a WAVE. And this is why electricity and magnetism are linked. You can flip the process and have a wave excite a particle (for example the electrons inside a cable). But you don't create electrons from nothing, nor you ever "move" them. They seem to move, but in reality they pass their energy and momentum to the next one, like the metal balls of a Newton's cradle.

  • Patinho
    Patinho 19 days ago

    Genuine question; When the energy leaves the battery where does it go? And when it come into the bulb or motor.. where does it come from?
    I remember the direction of the energy movement given my the Pointing rule. But where is it stored? In a tired? In the universes quantum soup?

  • ThinkerOnTheBus
    ThinkerOnTheBus 27 days ago

    5:02
    Key point missing from explanation of method is that it is only applicable to the right hand, hence it is one of several uses of what is known as the "right-hand rule".

  • Nature Medic
    Nature Medic 23 days ago

    One Question Professor, what makes you so certain that this theory is correct? Aren't they too who discovered that current flows in a wire to the bulb or its destination as certain as you are now? Including all the other theories that educational institutions thought even now as we speak?

    • J Modified
      J Modified 23 days ago

      Current does flow in a wire to the bulb. This video does not say otherwise. The energy associated with that current flows outside the wire, or at least that is a reasonable way of looking at it.

  • Sammy Gillespie
    Sammy Gillespie 6 months ago +212

    With such a long wire, how do the fields "know" where to go? How is it able to transmit energy immediately, but a disconnected lightbulb another meter away wouldn't power on? (or maybe it would?) In fact, how does current "know" to start flowing when the circuit is complete?
    Or what would happen if you cut the wire at one of the tips? Would the field instantly start receeding everywhere? 1/c seconds to turn off?

    • qewqeqeqwew
      qewqeqeqwew 6 months ago

      @Supertyp No, you don't.

    • Jot Pe
      Jot Pe 6 months ago

      if Derek were right then PCB trace length matching in High Speed Design would not make any sense.
      My suggestion for Derek is to repeat the experiment and measure the time with 2-channel oscilloscope. One channel probe connected to the switch, the second one - to the bulb. Don't even need 300000km of wire, couple of meters would be enough. Right, energy is transferred by EM field, but along the wires.

    • Zeno 42
      Zeno 42 6 months ago

      Your conclusion is correct--with an "ideal" bulb that needs any arbitrarily small amount of current to turn on, you would not even need to connect it to the circuit while the current in the wire is changing. To answer the part about the fields "knowing" where to go, well, they actually don't at first. The fields that are responsible for "turning on" the bulb are not completely "directed" towards the bulb until the signal travels down the wire and reaches the bulb. Beforehand, what is really happening is the changing current in the wire is acting like an antenna and generating the electromagnetic fields outward in all directions. To answer you last question, "how does the current 'know' to start flowing", the current "signal" I mentioned is generated by the closing of the switch, and travels down the wire starting from the closed switch. Hope this helps :)

    • Outis Nemo
      Outis Nemo 6 months ago

      @Gohan Goku:
      Again, that's not quite right, because as I just pointed out, by discovering the underlying causes of the phenomena we see, we simultaneously gain the ability to engineer technology that nature would never produce on its own. Thus it's just as correct to say that science can create, and not only discover.
      And again, the latter paragraph you just mentioned just repeated the same logical flaw I pointed out in my above comment, namely that science does not just deal with discovering and describing, but with actively modeling and testing the predictions of those models to discover new phenomena that would never have been observed without the model itself. In other words, this process does absolutely answer the questions of why the behavior is the way it is, to a more and more accurate degree.
      There's nothing to say that we won't one day pursue this process to its ultimate conclusion and discover the ultimate reason behind absolutely everything.
      *_«Behind it all is surely an idea so simple, so beautiful, that when we grasp it - in a decade, a century, or a millennium - we will all say to each other, how could it have been otherwise? How could we have been so stupid?»_*
      *-John Archibald Wheeler*

  • Duke Of Hesse
    Duke Of Hesse 25 days ago +1

    I got as far as James Clerk Maxwell. From then on I found my mind wondering more about how I was going to cook a cheeseburger, grill or seared in a pan. But I liked the chain in the plastic tube part. That was pretty clear even if it is wrong.

  • Paul Knauber
    Paul Knauber Day ago

    If your theory is true, it would seem that if you place the load in a Faraday cage, and your power source outside of the cage (wires passing through tight holes in the conductive screen), then the load will draw no current when the circuit is energized. True?

  • Es Kensington
    Es Kensington Month ago +1

    I've got a question. So if electricity is actually traveling electromagnetic waves around power lines, why do we need thicker cables to deliver higher amperage?

    • Dennis Miller
      Dennis Miller Month ago +1

      @Es Kensington Yes, a multilayer PCB can be crazy, but having multiple layers, several for signals, and one layer for Ground and another for supply voltage sure helps. And fortunately only some of the traces on a PC motherboard are dealing with any power, while most are very low level data signaling

    • Es Kensington
      Es Kensington Month ago

      I understand the reasons for thicker cables, it is just this video makes it very confusing. Also I was imagining all these traveling electromagnetic waves on a 5 layer Motherboard PCB, enough to make you freak out LOL.

    • Dennis Miller
      Dennis Miller Month ago +2

      I'm not sure about this video, but in response to your question, seems to me that we must have electron flow in order to have the necessary magnetic fields that carry the energy. So we still need to concern ourselves with efficient electron flow, hence larger wires for larger currents.

  • Jennifer Broad
    Jennifer Broad 4 days ago

    Since information cannot travel faster than c, if I cut the wire at the 0.5c distance, it should take around half a second for energy to begin to stop being dissipated in the bulb. This begs the question, how does the bulb know within 1/c when the switch is turned on that the wire is continuous?