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The Big Misconception About Electricity

Veritasium
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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.

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References:
A great video about the Poynting vector by the Science Asylum: trvid.com/video/video-C7tQJ42nGno.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

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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

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18 Kas 2021

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Haven DeZeeuw
Haven DeZeeuw 8 aylar önce
I’m so glad this video exists. I use to completely not even understand how electricity worked, and now I still don’t.
fiiredark
fiiredark 23 saatler önce
😂😂😂
thefallenlad
thefallenlad 2 gün önce
rofl
KD Conqueror ⚡
KD Conqueror ⚡ 3 gün önce
I'm a BSc Electronics graduate 😁
Fahd
Fahd 3 gün önce
lol
westcoastmickey
westcoastmickey 4 gün önce
same
SparkyPete93G
SparkyPete93G 21 gün önce
I'm an electrician from the UK. This can be proven by holding a florescent tube near a power line. It will glow. My family didn't believe me so I showed them. So glad you explained this in a way they understands fully. Thankyou. Very clever.
SparkyPete93G
SparkyPete93G 6 dakika önce
@Col Name i said power lines which is ac and yes it is relevant.... magnetic feild creates the glow of the tube with out an actual connection. I feel you need to re watch the video lol. Thankyou for your opinion.
Col Name
Col Name 47 dakika önce
Yes, but irrelevant. The circuit in question is DC, not AC. You will not get your fluorescent to glow by holding it near a DC circuit.
CounterProductive
CounterProductive 12 saatler önce
So glad you are from the UK.
Loren Wilson
Loren Wilson 2 gün önce
The electrons in the power line are moving - back and forth if it's AC and down the wire if it's DC (very few high voltage DC power lines but they exist). You can build up an electromagnetic field without significant movement of electrons but you can't transmit power without them moving. The field and the electrons are all part of the same phenomena.
Dale Lerette
Dale Lerette 3 gün önce
This was very informative. Thank you for sharing. I did not know these things.
Andrew
Andrew 4 gün önce
Is it possible to encase the copper wire with a shield that would almost completely inhibit the magnetic field and (nearly) completely prevent current flow? If so, it would definitively prove this concept.
Keit Hammleter
Keit Hammleter 4 saatler önce
You've asked a very good question. And yes, you can obviously use a shield - and it makes absolutely no difference at all in the battery and light bulb case, where the current, which IS in the wire, is DC. Just buy some coaxial cable - use the inner conductor to carry teh current, and the outer as the shield. The shield will constitute a Faraday shield. A faraday shield is where you use a continuous conductor - and if it is a perfect conductor, no energy can go through it.
Thomas Silcher
Thomas Silcher 12 gün önce
I love the animations. They really help to easily visualize complex topics.
ScottV
ScottV 22 gün önce
I remember learning about this at university, and I was astonished that I had never heard of it anywhere else. It is perhaps one of the most interesting ideas in physics.
Lenny
Lenny 11 gün önce
Yes. It’s so unintuitive in some ways (wouldn’t we get hurt somehow if huge amounts of energy are being pushed through the space around us) but very elegant (I had always wondered why if electricity “flowed” down a wire it didn’t get returned to the power source) and even intuitive in others (if a wire physically connecting the source to the drain was fundamental in the way the flow of electrico-magnetic energy, how would wireless charging work?)
MattMGK
MattMGK 6 aylar önce
After watching this video I can confidently say I understand less about how electricity works than I did before.
Amazuri
Amazuri 12 gün önce
@Edward Mc ^ Same question as before.
Amazuri
Amazuri 12 gün önce
@Edward Coulter Do you honestly think global warning is false? Not trying to mock you or imply anything, just curious.
Zubleo
Zubleo 18 gün önce
Bruh it's so true
MattMGK
MattMGK Aylar önce
Guys. It was a joke. It's been 4 months. I don't need more notifications.
Jon
Jon Aylar önce
you understand more, than before you just never realized how little you knew in the first place
Knights of the Nine
Knights of the Nine 9 gün önce
I kind of wish this kept going and explained how this relates to voltage, current, and resistance.
Keit Hammleter
Keit Hammleter 3 saatler önce
No you don't, because the presenter has little understanding of his subject and has made several key mistakes. He's read a few books, dropped a few names, and regurgitated without really understanding them. See my other post. Contary to his claim, electrons do carry energy - as kinetic energy (as you learnt in high school science, 1/2 m x v-squared) as they have mass. Resistance occurs when moving electrons bounce off the nuclei of atoms in a conductor, changing their direction and transferring some of their kinetic energy to the atoms. So the atoms get jostled about, which we measure as a temperature rise. And the fact that the electrons end up travelling in somewhat the wrong direction as well as loosing some speed show up as a reduced current and a voltage drop.
Knights of the Nine
Knights of the Nine 3 gün önce
@sean roland Watch electro boom response and varitasiums follow up
sean roland
sean roland 4 gün önce
I was actually trying to wrap my head around the more practical side of this as well. The relation between A, V and R are all taught based on the traditional understanding. That’s how I determine which wire size to use, or how to properly protect a circuit. It seems to me that all that goes out the window now and I would love a real world explanation of how to approach these problems that I use to think I had cemented
JiisTube
JiisTube 10 gün önce
Great video, and a perfect example of how our scientific discoveries actually happen. Once we are clever enough to get something working, we make up all kinds of BS about how it works and why it works and "what's really happening", then we go through decades and centuries disproving and rewriting the how and why, while all along it continues working. In college I heard three different claims on how basic electrical current works, and regardless of the arguments and contradictions, the fact is the electrical parts work just fine regardless of what you believe is happening. One professor pointed out that you can use the same calculations even for what's not really happening, and it works just fine. Funny and interesting stuff.
Keit Hammleter
Keit Hammleter 3 saatler önce
Very well put, and spot on. It always amuses me that people think that mathematical models are the real thing. As a working electrical engineer, I can tell you that the art is in using the right theory for when it DOES give the right answer in calculations, and another theory for when it DOESN'T.
Cody D
Cody D 15 gün önce
It does make sense considering. I always wondered if that is the reason why as part of a IT class a few years back they mentioned not running a cable next to fluorescent lights, because it could cause interference.
prestonscott73
prestonscott73 20 gün önce
I took two classes with professor Hunt at UT back in the 90’s - I recognized his laugh immediately. Fascinating to see him here.
Dylan Dailey
Dylan Dailey 8 aylar önce
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.
ThePythonicCow
ThePythonicCow 5 gün önce
> Yes. The quantity "1/c" is NOT a time. It's a time divided by a distance. The video should not say something will take "1/c" seconds to happen, because "1/c" is NOT some quantity of seconds. Perhaps you are right, that the "1" is intended to be "1 unit of some distance", where that distance happens to be the distance between the two parallel cables.
Nicola Ciocchini
Nicola Ciocchini 10 gün önce
Great comment. The video was misleading: it brings to the natural conclusion that you don’t need wires in any type of circuit from power lines to integrated circuits. That is obviously wrong.
Shai Revzen
Shai Revzen 11 gün önce
Professor of EE here from U Michigan. Thank you, Dylan. You pretty much wrote what I wanted to write, except for the fact that the field strengths decrease polynomially, depending on the shape of the wire - not exponentially. They do, however, decrease exponentially in an insulator, which is what makes it insulate.
Commenter Of Truth
Commenter Of Truth 2 aylar önce
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 3 aylar önce
Thank you, its much easier to understand!
Re-Tech Education Support
Thank you Sir I also have the same question I asked many professors but not get clarified But you made it clear Thank you 😊 Do more fundamental things like this I have some questions out of which I would like to ask one question How 0 and 1 is stored in the flip flop It is Nothing but 2 cross coupled gates. Which are made up of transistor
Savas X
Savas X 24 gün önce
Paused the video to thank you for the amazing content you keep pumping throughout all those years. Seeing your content feels more illegal than downloading books from pirateBay in terms of the value i get versus the price i pay for it. This is what education should be like. A huge thank you from an aspiring creator living in a small city near Athens, Greece. You will always be one of the first channels that pops to mind when someone asks ''How can you get valuable insights and knowledge from watching youtube?''
Matthew Lydon
Matthew Lydon 2 aylar önce
I learned a little about this topic in Marine Mechanics School. Talking about a/c to d/c power distribution and the intricacies of how it gets delivered. And how energy flows from negative to positive. Coils, magnets, and motion. Crests and Valleys. Pretty interesting stuff. Cool video. Thanks.
Alex G Reid
Alex G Reid 4 gün önce
So my question now is how do those electrical and magnetic fields work in something like a motherboard or a CPU? The routes of copper in those are very close together, especially in a CPU die. Does the fibreglass in PCBs or the silicon in the wafer die stop the fields from affecting each other? Or are the fields tiny enough that they would never get close together in the first place?
v1das007
v1das007 3 gün önce
Not a physicist. I think that the insulating material stops this, and therefore they can't interfere with each other to a degree where it becomes an issue. However, there is a limit of making the CPU even smaller and have more transistors in the same space due to quantum tunneling - at least that's what our physics class in uni taught us. Modern CPUs are almost reaching this level.
lv8pv
lv8pv 8 aylar önce
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 3 aylar önce
​@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 3 aylar önce
They applied themselves to understand it . They even respected it. Interesting
creative intentions
creative intentions 8 aylar önce
That's crazy. It's not water
Cmdr Sighman
Cmdr Sighman 8 aylar önce
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 8 aylar önce
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.
Sara T. Wofford
Sara T. Wofford Aylar önce
In addition, not shown in the video, there’s also a significant component of magnetic field circulating around the current, separate from the radiating waves. Combined with the electric field in the wire, *that* ExB Poynting vector sends energy *into* the wire, which is why the wires heat up.
Han Nguyen
Han Nguyen Aylar önce
Thanks for this work. These days fuel cells are becoming more popular. I have been trying to apply what you said in this video to how energy flows in a fuel cell application. I read that in a PEM fuel cell, as Hydrogen enters the anode, simply put, it is divided into H ions and electrons. The H ions go through the membrane to the cathode. The electrons can not go through the membrane so they have to flow on a wire connecting the anode to an energy consuming device and then on another wire to the cathode where they will recombine with the H ions , separated earlier , and the Oxygen from the air intake to form water as exhaust. In this case matter , H2, is consumed to make energy. And apparently, parts of the matter itself flow to make energy. If it is not too much to ask, I would like your help to understand how your thinking about traveling electromagnetic field and electrons work in this scenario. Your explanation will be appreciate tremendously. Sincerely
Jon Smith
Jon Smith 11 gün önce
In a fuel cell you have a micro perforated metal plate with a porous electrically insulative ceramic coating on one side. The fuel (H) is supplied to the ceramic side and the oxygen to the metal side. The oxidation of H is the transfer of an electron from H to O but this process is interrupted by the ceramic trapping the electron. To complete the process the electron is gained from the metal (metals have free electrons). This causes the ceramic side to have a negative charge and the metal to have a positive charge and therefore a potential difference between the two. I know this doesn't answer your question but it might help to better understand the concept about which you are asking the question.
FleaOnPeanut
FleaOnPeanut 22 gün önce
Darrick helping us by replacing a sensible way to understand electricity with one he doesn’t adequately explain and leaves us all confused. But I now understand that electricity can jump between to close circuits. Revolutionary. Dope.
D I
D I Aylar önce
Very interesting,I was taught that current flowed like a gas cloud of electron trough the the surface of the wire(conductive material)
SyTy
SyTy 8 aylar önce
I am a lowly aircraft electrical technician and mechanic. But from troubleshooting aircraft systems over the years, a fuzzy picture started to form in my head almost exactly like what you illustrated. And I've used that image to do mental checks in my head against where power is going, and if my diagnostics are correct or I have my test equipment in the wrong place. This video completed the puzzle in my head, and I think a lot of people in the blue collar world who work with electrical systems every day without ever defining the knowledge they've learned from it will appreciate seeing this video.
Shadow Gauge
Shadow Gauge Aylar önce
Then you will understand this, why do we derive motion is the driving factor in the production of power and energy, this naive assumption force is power when force is an endothermic reaction. As is motion, when we know heat is energy. While I did find myself grateful for the video by the end, and I do very much appreciate it because they tell us what energy isn't.. Thou I would argue in a sorta pointlessly lavish and difficult to understand way (like that statement)... And not even mentioning that heat and voltage literally have a 1 to 1 ratio, just kinda seems like a waste of breath. And you said it, I wonder where the power goes... But at the time if you knew that heat was power, and motion was not, wouldn't you have felt more of a clarity of understanding. Tesla lit up flashbulbs with heat leached from the earth by cold mountain air as the sun settled behind the rocky mountains.. it wasn't magic, it was just thermodynamics.
Butters Da Baller
Butters Da Baller 6 aylar önce
@SyTy LOL well said SyTy! Machinists make em perfect, mechanics keep em workin' and the pilots just have to fly it!
frickxnas
frickxnas 8 aylar önce
@John Martin Well safety is really complicated. Most engineers that do maintenance care about the reliability of the aircraft but that doesn't always lead to safety. Let that be properly handled by manufacturers and the complicated design and production stages.
John Martin
John Martin 8 aylar önce
@SyTy I'm sorry but safety in aviation is responsibility of everyone involved. So I do have right to point at (possible) gaps in your work, just like you have the same right to point at mine. I see what you say. I'm glad that my worries turned out ungrounded - please keep up the good work.
SyTy
SyTy 8 aylar önce
@John Martin this is a very vein comment. And honestly kind of something I'd expect to hear from a first year student, not a pilot. Performing maintenance and performing troubleshooting are two entirely different realms of work, this is why troubleshooting is always followed by a maintenance action called an operational test. I suggest if you don't work on aircraft, you stay in your own lane and not make virtue signalling comments on TRvid telling me how to do my job.
JordonMMG
JordonMMG 2 aylar önce
I'm still trying to process this. If the electricity is traveling through the fields around the conductor, when then do we only get shocked when we touch the cables? Is it because the energy we are working with is so weak, the fields are hardly noticeable? Electricity has always confounded me. (Edit) So going back to the intro question, what if you move that light bulb out to max distance from the source? Does that change the speed?
eclipse
eclipse 2 aylar önce
Electrons passing through your body cause shocks. The electromagnetic field only moves electrons in the wire forwards, the energy comes from those electrons. The energy in those electrons comes from their movement, the movement comes from the electric field, therefore the energy actually comes from that electric field which creates the movement. For a longer and better explanation you should watch Veritasium's newer video on this topic, where he clears things up. It's called "How Electricity Actually Works".
Ezequiel Palmas
Ezequiel Palmas 2 aylar önce
Because of the frequency, won’t get shocked with 12v from vehicle battery but one will definitely feel energy from 120v
Alexander Grom
Alexander Grom 25 gün önce
That was very educational and well done, thank you!
Silvio Martinez
Silvio Martinez 18 gün önce
Well, it's a little controversial, because in maxwell's equations, especifically the fourth, he introduce the concept of displacement current, refers a flow of energy due a variation in electric and magnetic field in a capacitor (this concept was introduced for completing the amper's law called amper-maxwell equation). It means, in a simple circuit like show in the video, if you introduce in series a capacitor, the flow of energy continuous but it depends on if the source is a direct o alternating current. What is that means? the flow of energy occurs if the magnetic and electric fields are variables, for that reason, there are not electrons moving around the circuit (that model tells you, the electrons don't jump from one plate to another). the same happens, in transformers, variables magnetic field induced variables electric fields and then a current appear. 😃 Energy travels in conductors.
SuperElwira
SuperElwira 3 gün önce
Maybe energy can flow in 2 directions in same time depends from the electron spin.
Karim Naufal
Karim Naufal Aylar önce
After 5 years of electrical engineering, I now understand electricity a tiny bit better!
number 33
number 33 8 aylar önce
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 3 aylar önce
Derek probably did read your comment
George Hnatiuk
George Hnatiuk 8 aylar önce
@Coco Sloan time = distance/c so yes, 1 second = 300 000km/(300 000km/sec)
Coco Sloan
Coco Sloan 8 aylar önce
@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 8 aylar önce
@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 8 aylar önce
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 !
sizlax
sizlax 2 aylar önce
Yea.. I always thought it was the water through the hose analogy as well. I think your example of this may make more sense to people if you had a tool capable of gauging the electrical energy at a point in mid-air. I mean, if what you say is correct, then such a tool would have a heightened energy reading while it's sensor is near an electric wire. In theory that is, I'm not a scientist myself.
Syntrixx
Syntrixx 23 gün önce
Thank you for this video. I previously thought I didn't quite get how electricity works. Now I am sure I have no idea how electricity works.
matneu27
matneu27 2 aylar önce
As an electrician and electronics hobbyist I heard about the "skin effect" increasing with the frequency of the source and that the inner core of the wire becomes useless with ac. If I understood this brilliant video right, we also have a skin effect on DC?
Helmer Mussell
Helmer Mussell 2 aylar önce
The skin effect supports an electron flow theory... not a field theory
AmmaLeslie
AmmaLeslie Aylar önce
Thanks for letting us know that the wire spacing was not to scale. That was helpful!
Sam Gralla
Sam Gralla 8 aylar önce
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
Jurgen
Jurgen Aylar önce
Accurate comment
Lady Mercy
Lady Mercy 8 aylar önce
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 8 aylar önce
@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 8 aylar önce
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 8 aylar önce
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
Lorp is
Lorp is Aylar önce
When I was studying this, I would imagine lines of flux being extended and refracted through and around the wire when being cut by it. Much like watching refraction in a glass rod while waving it around in front of vertical blinds.
Lorp is
Lorp is Aylar önce
@Aleph Zero Another thing I discovered while looking into the sciences in general is it's not nearly as challenging as it appears when you strip away the old-school class language bridge. I wonder how much human potential has been wasted by the upper class pretending they were so superior while keeping those words to themselves and looking down on those who didn't know them. I find it hilarious when they use them and don't know what they mean themselves.
Lorp is
Lorp is Aylar önce
@Aleph Zero Glad to see You Tube commenting isn't a complete wast of time. That's just the surface. There is some magic with transformers, collapsing magnetic fields, spark gaps and radio. The things that really grabbed me was how magnetic fields act like a different sort of mass; and, how they propagate through empty space.
Aleph Zero
Aleph Zero Aylar önce
So I'm back here to say thanks. Your intuition was spot on because those United States military videos were perfect. It answered a question I've always had: why do we generate A.C. power? It turns out circles are practical from an engineering perspective and we know circle-maths very well. Your imagination of the flux bending and refracting is awesome.
Aleph Zero
Aleph Zero Aylar önce
@Lorp is thank you very much.
Lorp is
Lorp is Aylar önce
@Aleph Zero It's in reference to generator. when a wire quickly passes through a magnetic field, it was said to automagically create voltage in my intro class. That field is made up of many concentrated magnetic paths called flux. For many reasons, it made more sense to consider those lines being extended through and tangled up on the wire that supposedly breaks them when passing through. I don't know if it's accurate but it was a useful construct for remembering and hasn't been shattered yet. I have no idea what you know, if you're just starting out, there is a very good US Army DC and AC machine training video series on you tube that can elaborate. They are old but the best demonstrations I have ever seen.
Tangodown282
Tangodown282 Aylar önce
As someone who has worked with electricity and electronics most of my life, I have a hard time wrapping my head around this. The conventional wisdom of current flow has kept me alive all these years and the only interaction I've felt regarding fields of any type has been hairs on my arm standing up. I don't dispute the original experiment results, and I would probably buy this as a neophyte exposed to the purely academic argument, but as an experienced tradesman, I have serious doubts. As a single practical question, how is it that I can sometimes physically hear a 60hz buzz on an AC transmission line if the current is barely moving?
Burbituate
Burbituate 26 gün önce
Stuff taught to technicians, is lumped phenomena labelled V, I & R ...but really all defined from calculus of (really Heaviside's) Maxwell's Eq
Michael Murphy
Michael Murphy 29 gün önce
In truth you don’t actually hear them. What you do hear is called the beats phenomenon. The difference in resonance of sounds in each ear.
Kenneth Carpenter
Kenneth Carpenter Aylar önce
The magnetic fields created by current carrying conductors is the basic concept on how electric power generators function. Learned this in the Navy working on the Motor Generators on Submarines.
Tangodown282
Tangodown282 Aylar önce
@Jim Figgers I should have been more clear; I wasn't talking about the loud and obvious HV xformer buzz, I was talking at or downstream of a residential service panel. Breakers, disco boxes (literally the terminal blocks) and even rigid conduit will sometimes buzz.
Emmanuel Ikhile
Emmanuel Ikhile Aylar önce
the current you refer to is actually the energy flux generated by the electromagnetic fields.
QQpapababy
QQpapababy 2 aylar önce
Thanks for the video. If we stand under the wire which inside a current flows, are we influence by the Poynting vector? Is it something additional to or the same as the magnetic field by Ampere's law?
Keith McAuslan
Keith McAuslan 2 aylar önce
Thank you so much... I have some basic questions about electricity for years, like how can AC have a hot side if the push pull is constantly changing. You have helped me to understand this in more ways than anyone else. BUT, how can electrical current kill or throw you if there is no flow; how does the magnetic field do the harm?
Brian Leong
Brian Leong 26 gün önce
Based on this video, I imagine this is close to the answer: First we are conductors just like the wire because we are full of electrolytes due to sodium and potassium in our mostly water bodies. When you touch a circuit, you become a part of the closed system and the potential difference is extended through you and the ground. Even if electrons are not flowing through you, you have become the wire and the electrons in your body are oscillating due to the electric field, which gains significant energy generating heat causing you to burn up.
Twitchy63
Twitchy63 Aylar önce
Because the neutral side has a MEN link which links the Neutral to earth, if it wasn't connected to the earth cable the voltage would be the same in both phase and neutral.
Mr. Jason
Mr. Jason 8 aylar önce
This actually raises more questions than it answers.
Fullson Chuang
Fullson Chuang 5 aylar önce
@noise5555 1/c is time, not velocity
gordo teton
gordo teton 5 aylar önce
welcome to actual science
Q Revere
Q Revere 8 aylar önce
@Jaden Prayers for blessings of wisdom and good fortune.
Jaden
Jaden 8 aylar önce
@Q Revere such big words yet you can't seem to find the period button. Here copy and paste mine ".".
Q Revere
Q Revere 8 aylar önce
@Marko Topolnik This would make much more sense, while also making many much more angry, if you incorporated dielectricity into your model.
Jason Zacharias
Jason Zacharias Aylar önce
I wish my teachers focused more on understanding and less on social engineering, thank you sir, I proudly call you a real teacher and bringer of the truth!
Terry Last
Terry Last 22 gün önce
I was in a team writing about electricity. We looked at "What is electricity"? We found the answer depended on who you asked. The electricians said the flow of electrons. The engineers said the flow of charge. The wave guide people said the flow of electric/magnetic fields. We know electrons store energy by moving to higher orbits. Do electrons store and release energy and transmit it to other atoms by radio wave? Do electrons move back and forth like a conga line reversing direction? If so how much mass is shunted back and forth along a transmission line and why doesn't the line wobble at a resonant frequency. (they do hum, that's why the AC frequency is below human ear sensitivity) We decided to describe electricity as the movement of charge with drifting free electrons slowly along for the ride. The charge moves because of entropy. The moving charge manifests as electric/magnetic fields. We agreed the real answer was in the relm of the particle physicists and as we were not teaching physics students our description would offend the least number of people. The short answer was "electricity is energy channeled by wires. I still don't know if a charged capacitor has one heavy plate and one light plate. Do you? T
Ronin Lviaquez
Ronin Lviaquez 8 gün önce
If by “below human sensitivity” you mean 50 and 60 hz, I have bad news for you
EJP
EJP 9 gün önce
AC frequency is not below the limit of hearing. It is several octaves above it and is readily audible. A double bass or bass guitar can okay it and a baritone or bass can sing it.
Samir Chettri
Samir Chettri 9 gün önce
No
Helmer Mussell
Helmer Mussell 2 aylar önce
There could theoretically could be a continous wire from the power plant to your house if it outputted 120/240 V or if you had your own generator
Madame X-Wing
Madame X-Wing 2 aylar önce
Love this video. Very intriguing. Thanks for putting this out for discussion. One thing, though, that I don't understand is the answer you give of 1/c s. I think this is incorrect, and should be written as 1m/c so that the dimensional analysis creates an answer of (1/300,000,000) seconds. If dimensional analysis is performed on 1/c s, the answer is in seconds squared divided by meters, which doesn't make any sense. Am I missing something?
Madame X-Wing
Madame X-Wing 2 aylar önce
@Kenneth Schroeder Yes, you're correct that the presenter is making the assumption that the dimensional analysis has already been done, but including the "c" reinserts the units of measurement of meters per second. It's not mathematically correct to add seconds to the "answer" of 1/c, and it's also not mathematically correct not to include meter in the numerator.
Kenneth Schroeder
Kenneth Schroeder 2 aylar önce
If you consider that the presenter has already done the division of 1m / (c m/s), and canceled the m/m out, then he is just stating the final time travel result in the final unit, seconds. It's not easy to show full actual dimensional analysis here but I changed to all fractions and multiplied factors .....[Distance] / [Speed] = [Time].......is the same as [Distance] x [1/Speed]....or [(1meter)/1] x [(1sec)/(c meter)]. Maybe that will help a bit?
Kamil Pekala
Kamil Pekala 8 aylar önce
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 8 aylar önce
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 8 aylar önce
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
Grant Harding
Grant Harding 10 gün önce
Dumb question from a biology major who never "got" electricity in high school: If the energy flows through the field, not through the wires, then why does the lightbulb need to be connected to the circuit at all? Couldn't it just be next to the circuit, and still work?
James Martian
James Martian 5 saatler önce
Would that be what Nicola Tesla wanted?
jason389
jason389 4 gün önce
@Chris Gassen I checked your work. For grammar. Because I don’t like letters in my math.
Fatty Tan
Fatty Tan 6 gün önce
According to some of the people in the comments. Apparently the energy flows extremely close to the wire. So you would need the disconnection to be extremely small for it to work.
Chris Gassen
Chris Gassen 7 gün önce
Electric field falls off as 1/r^2 and magnetic field as 1/r so perhaps it’s a proximity issue as that would greatly decrease the magnitude of the Poynting vector at larger distances. Definitely not a dumb question btw
Ng En ze (Msh)
Ng En ze (Msh) 7 gün önce
@Mar electromagnetic induction?
PersonwithaName
PersonwithaName 2 aylar önce
If one was able to dampen the electromagnetic waves from traveling around a power line, would that thus mean no electrical current would be transferred? I mean if you could shield the cable somehow from allowing these waves from extending outside of the cable itself.
Benjamin
Benjamin 2 gün önce
Since electrons flow from high potential (negative) to low potential (positive) with the delta potential as a voltage, is it dangerous to touch the positive side of a DC circuit since it has a low potential and thus doesn’t push electrons out towards you?
Erion
Erion 24 gün önce
What a great topic. In school you never thought about this stuff and just excepted what was told. Great video, great channel. Best regards from germany.
AT
AT 4 aylar önce
The fundamental law of physics: electricity disappear if you stop paying bills.
McMerry
McMerry 22 gün önce
@Richard Mcalalkans mmm but you could also build a kind of giant cyclic system fed by gravitational acceleration. This clearly doesn't exist, but my imagination is big, will it work? Maybe, maybe not...
McMerry
McMerry 22 gün önce
@Richard Mcalalkans they certainly could, but you need to "catch them" somehow and since we all move with it by inertia, it would have to be or...deep inside the core, or outside the atmosphere. At least you can feed your electric turbines to generate power with geysers coming from the earth.
McMerry
McMerry 22 gün önce
@Satoshi Nick Szabo your desires to scape from poverty
Mareinna Shaw
Mareinna Shaw 3 aylar önce
Not if Nikola tesla was able to complete his work... we'd all have free energy
Flo1
Flo1 2 aylar önce
Thank you. I m wondering of this since I m 12. I m almost 40 now and I finally got the answer. To be honest i would not be able to understand it if it was not explained like you did.
LA2STA Laboratory
LA2STA Laboratory 2 aylar önce
Would be interesting to see how he explains electrical conductivity and semiconductivity with his theory. Especially when it comes to doping semiconductors to make p-type and n-type semiconductors. The presented theory is not thought through.
John Williams
John Williams 2 aylar önce
I assume this is why clamp meters can measure the flow of energy along a wire without touching it. This includes voltage and amperage. It would have been good if resistance were explained in terms of fields.
Madogg
Madogg 2 aylar önce
This is only partially true. Current and voltage flow through the wire. However, Electricity is light. As the Electricity travels the wires, some escapes as magnetic waves. This is how radio waves work, very very high voltages, and the magnet waves can escape the medium, Wire, etc. and travel through the air. Tesla failed because large currents can't be transmitted over the air. Most every electrical device, with few exceptions, require the correct diameter wire or there can problems. There is a law regarding this. Ohms law. I/E/R. You can look it up and study it if motivated. The title was "CLICK BAIT" and it worked. 14 million views and counting.
Andrew Watson
Andrew Watson 2 gün önce
I have to admit a lot of what was said went over my remaining few brain cells, but I did have an "ah-ha" moment. Stats tell us that suicides from people living close to powerlines are significantly higher than those who did not. I remember reading one of Lyall Watson's books where he described hamsters and rats moving their young from one side of a cage to the farthest point away from an electrical current. It seems the rodents felt the energy around the powerlines, and fearing it, did what they could to protect their offspring by moving them away. I mean, after all, even us humans can hear the energy around the powerlines when we stand underneath them. Great topic--thanks for sharing. Oh, and my choice was E, none of the above. It was a wild guess, influenced mainly by my own experience of "All the above" or "None of the above" often being the correct answer.
Randall Parker
Randall Parker 8 aylar önce
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 2 aylar önce
@MarkoZBogdańca The tube itself is the 'loop'
makrisj
makrisj 3 aylar önce
@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 3 aylar önce
@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 3 aylar önce
@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.
Eudaimonia
Eudaimonia 2 aylar önce
Makes a lot of sense. Someone tried to explain the electricity to me with the water in pipes analogy and it just never made sense. This makes it perfectly clear, much appreciated!!
xbmono
xbmono 2 aylar önce
I have 3 questions: 1. If light is electromagnetic field, doesn’t that mean it can be distorted by a magnet? 2. What is the diameter of the electric and magnetic field around the wire? 3. If the light bulb is too close to the battery and the wires are connected to another device and not the bulb, would the bulb turn on by the field?
User DJ
User DJ 2 aylar önce
Yes, it can. A changing magnetic field induces and electric field and vice versa, therefore we have self-propagating electromagnetic waves. If you change a magnetic or electric field, waves are emitted.
xbmono
xbmono 2 aylar önce
@David Wester Thanks
David Wester
David Wester 2 aylar önce
This is a thought provoking video which has stirred up a lot of great questions, which is how science should work. If enough special cases are identified and cogently addressed, then maybe we can finally understand what the real truth is about electricity. As a corollary to question #3, I read about an atmospheric nuclear test conducted by the U.S. over the Pacific Ocean in the early 60's. The EMP was intense enough to cause light bulbs (which were not turned on) to spontaneously light up despite being many miles away. It seems that a field emanating from a very powerful energy source is indeed sufficient to illuminate a bulb or to affect electronics even from great distance.
Nabil Khalid
Nabil Khalid 2 aylar önce
I believe the misleading part is where he says the fraction of energy immediately reaching the bulb depends on the impedances. It rather depends on the distance between the switch and the bulb because the disturbance in the switch is generating the short term EM wave
David Simpson
David Simpson 2 aylar önce
I will guess: E. I'm guessing that the EMF (electro magnetic force already in the wire is like water in a pipe. When you turn on the water, you get what is already in the pipe. So as soon a current is introduced (which is a positive attraction, suction/vacuum so to speak), the draw of electron's EMF is immediate. That's my guess.
Mihail Dumitrescu
Mihail Dumitrescu 8 aylar önce
Derek is somewhat right about the time being roughly 1m/c for the bulb to light up but only because the parameters of the problem were picked to be tricky (sometimes fun and educative). Unfortunately Derek doesn't go into details in the video and only says that the bulb "won't receive the entire voltage of the battery immediately". This may mislead you into thinking that the signal speed in an electric circuit depends not on the length of wires but on the air distance to the switch, which is wrong. The signal speed in wires is roughly 50-95% of the speed of light and most often is what dictates how long it takes for something to turn on in most circuits. This is why, for example, matching copper trace lengths in PCBs is often important. Or why high frequency trading companies care about their internet cable lengths. HOWEVER, often in circuits there's significant wireless EM radiation, intentional (radio, wifi, microwave) or unintentional (reduced with EM shielding). Turns out that in Derek's circuit one side of the wire initially acts roughly like an antenna while the other acts like a receiver and the power transmitted could be enough to light up an LED bulb. At 100m it wouldn't.
Nova
Nova 7 aylar önce
@PCRetroProgrammer Causality isn't violated. You're just mistaken. Quite the personal incredulity. I don't know where you got the "MOST" when he did state in the video that it's only a fraction.
Fourth Root
Fourth Root 8 aylar önce
Thank god I'm not the only person who noticed the unit error. "1/c seconds" is not a unit of time. "1m/c" is. Come on people, this is basic arithmetic.
Kuba
Kuba 8 aylar önce
@vnet Explain why. We are waiting.
nvmffs
nvmffs 8 aylar önce
@vnet And 12 people liked it
Perry Nally
Perry Nally 2 aylar önce
This makes a lot of sense. But if the energy is actually being transferred through the magnetic fields then why doesn't a lightbulb light up that is near the original bulb but not touching the lines? There has to be electrical contact with the current, correct? Or does there?
Madogg
Madogg 2 aylar önce
Look at my recent comment. The title was "Click BAIT" so they can be paid. Look at Madogg statement that is 4 up from this. That statement explains ohm's law, the rules of electricity, how lightning works and why Tesla failed. Shortcut answer; power flows through a wire, and produces a magnetic field. But, Only high voltage is outside the wire causing a magnetic field. This is how speakers work, how radio transmission works. A car battery cable is VERY large in diameter. Because, a battery is low voltage but VERY HIGH CURRENT. If the battery wire was small diameter, 1/8", when try to start you car, the wire would melt nearly instantly. So, power does flow through the wire. RF (Radio Frequency) travels outside the wire. So, electricity is not 1 dimensional.
Downcast Overlap
Downcast Overlap 2 gün önce
So glad youtube recommended this video just yesterday I was studying Moving Charges this helped me greatly
Joe Knapp
Joe Knapp 13 saatler önce
Seems to be there's a problem with this thought experiment. You say that the bulb will light up in a couple of nanoseconds (the propagation time across the one-meter separation between the switch and the bulb). But what if there was another switch at one of the ends, one light-second away. If that switch is open then the bulb will surely never light up. So in effect, the main switch near the bulb is a way of determining the state of the switch at the end. I.e., one bit of information conveyed faster than light, as the bulb would light up in just a couple nanoseconds (or not) revealing the state of a switch one light-second away.
Patrick Malarkey, an old Irishman
You've got me confused, I think you might have introduced the magnetic coupling in a transformer for clarity about why power from generators doesn't actually reach your house. It reaches the transformer and the coupled transformer coils carry power to your house.
Matteo L.
Matteo L. 8 aylar önce
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 8 aylar önce
Poynting vector is a redundant term; all physicists know that vectors point!
Alex Maltais
Alex Maltais 8 aylar önce
I don't think this video is appropriate for a university course.
Randy Pittman
Randy Pittman 8 aylar önce
Once again I remember why I nearly failed E&M in college.
Eugene Bird
Eugene Bird 8 aylar önce
The vector isn’t a real thing, it’s just a mathematical device.
marvinalbert
marvinalbert 8 aylar önce
@Isaac Groen Actually arrow directions are pretty wrong, they're much more parallel to the wires.
Noah Roberts
Noah Roberts 2 aylar önce
This video really made me think hard about energy in general. I love this video.
Dolfin987
Dolfin987 Aylar önce
I am struggling through a book called Quantum - a guide for the perplexed by Jim Al Khalili. 2003. (This is readily available to purchase cheaply on the Internet). I did not study maths and physics at uni so the equations are beyond me but I am slowly coming to understand the basic concepts of this most amazing subject. I am particularly interested in the investigation of quantum gravity which is still a mystery. I have only watched your video once so have not yet grasped the full implication of what you are saying but I feel it is related to quantum physics. Thank you for your most interesting lecture. Before I watched it I just assumed electricity flowed down the wires like water in a pipe. I’m going to watch it again and again until I understand I think. I hope!
McMerry
McMerry 22 gün önce
I'm a Sport scientist and I literally spend more time studying this than my own area.
Craig Fowler
Craig Fowler 23 gün önce
He lives just down the road from me in Portsmouth UK. See him quite often, maybe I could get him to do a video on his book.
Ron Michel
Ron Michel Aylar önce
conned. google what is an electron, no need to understand math. then think of why water falls out of a pipe and why electrons dont. do not be suckered by this spin doctor or you will continue to strugle with this.
Jon
Jon Aylar önce
All of the physics shown in this video was worked out well before Planck's paper. It relies on purely classical physics
Paul Janssen
Paul Janssen 3 gün önce
The perfect example was AC versus DC DC cables absorbed the magnetism making them unusual for long distance and the massive size of the cables or AC different concept moving electrons back and forth lowering the copper to be more efficient in the use of moving electrons.
Tyson Atkins
Tyson Atkins Aylar önce
The next time you hear someone talking about electricity going "through" wires, ask them how the internet goes through fiber optic cables! Then research undersea cables, and ask yourself, "If our internet comes to us through cables, then why do we need satellites?" And, "If your ground position is triangulated between the cellular towers, and we have towers in the first place, then why do we need satellites?"
Jon
Jon Aylar önce
The wavelengths used in cellular communication are enormous, triangulating with them is possible but very difficult and extremely imprecise compared to using a gps system.
Geologian
Geologian 8 aylar önce
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 8 aylar önce
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 8 aylar önce
@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 8 aylar önce
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 8 aylar önce
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 8 aylar önce
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
Tik Tok
Tik Tok 14 saatler önce
Hi, can you make a vdo explaining how cross product(especially the direction of a cross product) actually works, and how scientists discovered it, as in how they found out that this is the direction of our resultant vector(which we got as a cross product). Like for example: in torque
Miguel Angel Hernández Gutiérrez
Hello, I believe that veritasium could enrich the theoretical framework that explains the difference between understanding electricity as a field or as a current of charges, adding that the standard model of physics, is a quantum field theory, which to explain the fundamental forces (strong nuclear, weak nuclear and electromagnetic forces) and particle interaction, the concept of force-field carrier particles or mediating particles is used, therefore each type of particle, in this case the electron, when interacting with another electron or with itselfs, is through photons, in that sense, the gluons are carriers or mediators of the strong nuclear interaction and the W and Z bosons mediate the weak interaction. Feyman diagrams are a very didactic way of understanding the interaction between electrons at this level, further study of the complete topic is by referring to quantum electrodynamics. Now, answering the question of whether there is a "push", the photoelectric effect would show us that when we irradiate a metal plate at a specific threshold of the electromagnetic spectrum, there would be an emission of electrons, however this is explained by the increase in the kinetic energy of the electron due to the transfer of energy by the photon, which would be complemented by the Compton effect which establishes that the wavelength of a photon increases when it interacts with an electron and loses part of its energy, respecting the conservation of energy and momentum, being able to calculate the emission angle of the photon. It should not be interpreted as a collision, since it does not apply to particles without mass and at least from this view, a particle would be understood as the minimum excitation of a field, therefore a particle can be originated through the correct excitation of a field, as it was when the Higgs boson was known through stimulation of the Higgs field Does this mean there is a "push"? no The electrons are not traveling or moving around the conductor wire, they would be tied to their constituent atomic nucleus, transferring energy to each other through mediator particles. The mediator particle of the electrons in the phenomenon of electricity would be the virtual photons, and in fact, with the experiments that prove the Casimir effect, virtual photons in the vacuum have been converted into real photons, due to excitations of the electromagnetic field, as of all the other fundamental fields, the minimal perturbation in a field would correspond to an elementary particle.
Enrique Torrente del Valle
I just love this guy. Well the first assumption is that the positive pole doesn’t really do anything but receiving electrons from the negative end thus disregarding the positive pole completely. The charge is in the negative pole with electrons and due to the electron binding in metals they start bouncing the electrons that are situated like on a China checkers. How long would it take for this accumulated momentum to turn out in the other end of the cable? I heard that it travels with the speed of light but I’m not sure. I will still say one second like the speed of light.
JamesBourne /gentlemanghost
My basic understanding is wrong. Mind blown! Always learning! Thanks for the video!
Backlash
Backlash 6 aylar önce
WOW! I'm 80 years old. Started learning electronics in the Army in 1959. We were taught the "Right Hand Rule" in the study of inductors and transformers. Although we knew about the magnetic field around conductors we never applied that knowledge like this. Thank you for teaching an old man a new trick.
Backlash
Backlash 5 aylar önce
@Matt Donahue Exactly! That poor elephant.
Matt Donahue
Matt Donahue 5 aylar önce
@Backlash you must mean being "westinghoused"?
solarsynapse
solarsynapse Aylar önce
Interesting. In a chemical reaction such as a battery, electrons are moved changing the chemicals while releasing energy. When the electrons move from an outer orbit inward, they release the energy that was keeping them there. In a capacitor, electrons are collected on the negative side until they have a path out.
buscador2007
buscador2007 2 aylar önce
Now I understand less than before, thank you for making a simple circuit so complicated and plain boring.
swapnil jain
swapnil jain 23 gün önce
I am with you on this, and I think this is the correct explanation. this proves tesla was on to something to create a system in which we don't need wires to travel the electricity. " A world without wires"
VINEETH RAMARAGHAVAN
I was pondering for a long time on the question of self induction.. it is established that the momentum lost by charges are being gained by it's field.. and there arises the question of back emf due to the stationary conductor and changing flux.. every one and every literature out there have one answer- nature abhors change.. but none seems to explain the pathways of momentum between filed and moving charge, causing this prevention of "change"..
Honor4OP
Honor4OP 8 aylar önce
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 8 aylar önce
@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 8 aylar önce
@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 8 aylar önce
YES this is exactly what I was thinking the whole video
Marc Fruchtman
Marc Fruchtman 8 aylar önce
@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 8 aylar önce
You could add insulation between the wires and the conductive sphere.
Etech2x Won
Etech2x Won 2 aylar önce
Well i guess I've been doing it wrong all these years, but it worked. I still think of current like water in a pipe except that voltage is a "negative" pressure causing electrons to flow from negative to positive potential. The electrons are similar to a train on a track. As soon as motion starts on one end, you see it on the other instantly. Not taking into account compression or anything mechanical to cause delay. I'm not saying electrons carry energy, but create a magnetic field around the wire when they are moving. The electrons don't have to travel all the way to the house. They make a loop in the transformer and return to the power station. The current in the transformer creates a magnetic field that induces current in the secondary winding of the transformer and that current or electrons travel to the home and return to the secondary winding. There is a delay in voltage in the coil hence the induction motor. If electrons are moving so slowly then how does a lightning bolt move so fast?
バナナお爺さん
バナナお爺さん 13 gün önce
To know this matter with more context and a lot more history, "shock and awe : the history of electricity" is a very good documentary to get you into this subject
Kismet
Kismet 3 gün önce
Brilliant. Had no idea. I love to learn new stuff! ❤️🤘
Adrian
Adrian Gün önce
What about connecting a bulb with a coaxial cable which has both positive and negative parts together? In this case, the energy goes inside the cable, according to Gauss law (for analysis of electric field) and Ampere law (magnetic field). The time in this case would be relative to the length of the cable, I suppose.
Dalnore
Dalnore 8 aylar önce
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 3 aylar önce
@Antonio Monzon Derek didn't have meters in the numerator. 1/c is not the same as 1m/c.
Antonio Monzon
Antonio Monzon 3 aylar önce
@Fourth Root [m]/[(m/s)]=s No unit problem there.
Fourth Root
Fourth Root 8 aylar önce
@wbeaty "1/ c" is not a number.
Fourth Root
Fourth Root 8 aylar önce
@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 8 aylar önce
@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.
bornagain bornagain
bornagain bornagain 2 aylar önce
Makes me wonder if this is the idea behind raising speaker wires off the floor. Any answers if it is an improvement or not?
Shaurya Mehta
Shaurya Mehta Gün önce
This is great knowledge! Thanks a bunch! 💡
Art Mills
Art Mills 16 gün önce
Please explain the operation of vacuum tubes (especially the Cathode Ray Tube) without electron flow in the wires. They did work very well until the advent of solid-state devices.
Sam Bean
Sam Bean 2 aylar önce
This is interesting. I never understood how a Tesla coil could power something with no wired connection but now I can kind of see how if someone changed some variables (gross oversimplification) it could be theoretically possible
Sammy Gillespie
Sammy Gillespie 8 aylar önce
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 8 aylar önce
@Supertyp No, you don't.
Jot Pe
Jot Pe 8 aylar önce
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 8 aylar önce
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 :)
Hoon Sol
Hoon Sol 8 aylar önce
@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*
ULTRADRIVE79
ULTRADRIVE79 2 gün önce
Every charged atom has a field. I usually only work with DC current. I understand that longer low wavelength frequency has the best results on larger conductors and higher frequency works better with skin effect. Paul McGowan did a video explaining different copper crystals and the way audio works with wire explaining this. My question is this. If energy travels through fields and not conductors then why are all the major connections with high current capacity almost exclusively made with large solid core termination with a large mass? Wouldn't it be more conductive if wire was broken up into fine strands that all had a field of their own?
KOTOR Fanatic
KOTOR Fanatic 2 aylar önce
Really wish you had covered insulators and how they interact with your description of how electricity works. I actually studied all of this in high school and again in college, and sadly, even for me, your explanation went too fast. Edit: come to think of it, you specified that the lines were resistance-less, but real lines do have resistance. If the electrons are just oscillating in place and the energy is being transported by the field outside the line, then how do those facts intersect with the concept of current density and the fact that a line can burst into flames if it has too much current flowing through it?
kaboom splash
kaboom splash 7 gün önce
I learned a lot from this video. thank you.
Michael Jeffrey
Michael Jeffrey 19 saatler önce
We already know that passing current through a wire causes flux to develop around the wire. I guess what confuses most of us is the "PASSING CURRENT" bit. We've all taken that to mean "PUSHING ELECTRONS ALONG"
TechPassion
TechPassion 8 aylar önce
I think the best part of this video isn't just the information it presents, but also the conversation it sparks in the comments! People asking questions, people trying to understand what's being said, and even people providing counter-arguments in certain scenarios where what Derek explains doesn't seem to match up. I think having civil discussions helps a ton, thanks Derek + the Veritasium community! This video and the comment section is genuinely interesting to go through
markmd9
markmd9 8 aylar önce
@zekicay let's expand the experiment a bit, Let's say that the distance is not to the moon but to About Mars 30 minutes. You have a 12v battery, super conducted wire (no resistance - no loss in voltage) and 12v 💡. Can you please tell me what voltage will you have after 1/c seconds for the light to shine? Because 12v will come only after half an hour if there is no break in the line somewhere near Mars.
Colton Young
Colton Young 8 aylar önce
Agreed. The intense amount of focus required for me to keep up is well worth the payoff of learning what you have to teach. You truly have such a unique mind and brain suited toward learning, curiousity, teaching, and excitement. Legitimately thank you for all you do Derek. Words can describe so much our appreciation for you. Sagan-esque as far as science educators go imho. Thank you for being you!
zekicay
zekicay 8 aylar önce
@markmd9 He is partially correct and partially wrong. There will be some small energy transfer between the bulb and the battery in 1/c but the bulk will happen after more than 1s.
Kanglar
Kanglar 8 aylar önce
I think he is being somewhat intentionally deceptive/vague in the video on purpose to cause this :P He's not wrong, it's just a weird perspective.
Rodney Jones
Rodney Jones Aylar önce
Watching this excellent video, I couldn't help but think of a Dave Barry article... "the electric company sends electricity through a wire to a customer, then immediately gets the electricity back through another wire, then (this is the brilliant part) sends it right back to the customer again. This means that an electric company can sell a customer the same batch of electricity thousands of times a day and never get caught, since very few customers take the time to examine their electricity closely. In fact, the last year any new electricity was generated was 1937."
Whaler
Whaler 3 gün önce
After watching this video. I kind of understood why Nikola Tesla thought about the idea of there being a possibility that electricity can be transmitted through frequency across the globe(Wardenclyffe Tower) in the future without having wires.
Sonam edu
Sonam edu 8 gün önce
Can you make more simplified video on working of Electricity... I didn't understand much...as we were taught differently in our school...But the video has increased my curiosity in electricity... Please can you make more informative video on electricity 😄 Thank you🙏
Up and Beyond
Up and Beyond 3 gün önce
As an electrician, I've been doing something I don't understand my entire life.
SnowArcs
SnowArcs 8 aylar önce
Not saying he's wrong overall, but in the specific case of coaxial cables (which are a wave guide) you can launch a pulse down the coax that travels at about 2/3 of light speed. This is easily measured with modern o-scopes. Since the undersea cable was a coaxial cable it would have functioned in the same manner. Dielectric and resistance losses were probably the biggest factor that doomed those first cables.
Dylan Dailey
Dylan Dailey 8 aylar önce
I believe the iron rings were causing areas of changing impedance on the cable. As the wave traveled past each ring, you'd get an attenuation, and a reflection of the signal. Since there were many rings, you'd get many reflections bouncing around, which ultimately caused the massive distortion at the other end of the cable. But yes, he does assume an ideal case, which does not account for the less-than-light-speed propagation of the signal through the conductor.
hausaffe
hausaffe 8 aylar önce
for a transmission line to work you have to match the impedance
NO Vac Joke a vitch
NO Vac Joke a vitch 8 aylar önce
@Victor Widell Yes but that is a balanced cable, this first cable had massive capacitance, and so slugged the signal.
arjay UU
arjay UU 8 aylar önce
Did this in an advanced Electrical Engineering lab during Uni. Was actually quite fun and precise measurable.
Victor Widell
Victor Widell 8 aylar önce
I remember meassuring signal ”blurring” in coax cable and fiber obtics with an oscilloscope in school. I think it was nanoseconds per 100 m of wire. How much would that add up to on transatlantic scale?
SpankMe Alot
SpankMe Alot 25 gün önce
Ok now I understand how I got hit by electricity so far away from the point I was standing , I got this rare thing going on where I attract electricity from distance , it’s usually just a little jolt , but one time it was from a power line , it hit my head and came out from my left hand , causing sever injury throughout my entire body , I survived thanks to another genetic anomaly , called the Olympic heart ( twice the size blood chambers ) . No one could explain how the electricity left the wires , traveled through the air and looped me in , since I was standing on the side , lower than the 3 wires , one expert said for electricity to travel that distance , needs to exceed 13700 v that theses wires carry , so nothing made sense
Col Name
Col Name 2 saatler önce
A further comment. The author asks how long it will take FOR THE BULB TO LIGHT, which we could reasonably interpret as meaning how long it takes until the full battery voltage appears across the bulb. And he is right, that there will be a small current that flows almost instantaneously, about the time it takes for light to travel 1 meter, because each of the long loops initially looks like a resistor, of resistance value equal to the characteristic impedance of the transmission line formed by the very long pair of wires. I can't be bothered working it out, but the characteristic impedance of a couple of wires separated by a meter will be fairly high, perhaps higher than 1000 ohms, and there are 2 such "resistors" in series. So the initial, almost instantaneous current will almost certainly not be enough to light the bulb, and can be ignored. The exact behaviour over the next few seconds, until the DC current has stabilized, will be complicated, and depend on the impedance of the lines and the resistance of the bulb, and perhaps also the nature of the soil on which these transmission lines rest. But one thing is certain. Once the DC current has reached a stable value over a few tens of seconds, and the bulb is lit, it is not the steady electric and magnetic fields that transfer energy from battery to bulb, no matter what the author may believe.
Steven Beck
Steven Beck 25 gün önce
I worked in Telephone Exchanges where there are thousands upon thousands of electrical circuits and most of them are bundled in the same place. Example you have a wire connecting A1 to B1 in one wire and another wire A2 to B2 and these 2 wires sit next to each other in a cable of 80 wires. According to Veritasium's theory the energy is NOT traveling in the wire but if this is the case then A1 could induce into B2 turning on the wrong load (relay for example). The only way the correct circuits are being used is if the energy is traveling on the wires. Just sayin.
adorbie queen
adorbie queen 25 gün önce
The graphs we see in the video of the magnetic fields are exaggerated. In reality, a simple wire is manufactured with plastic-casing to tightly bind these fields around it. Plastic is a great insulator since electrons, who carry a small charge and allow the magnetic field in the first place, don't enjoy it's lack of conductivity and thus are repelled in a sense. Your wires could have different casings, making the fields different and communicate only to themselves. They could be intentionally cross-firing energy if it's safer/more cost efficient to have many little wires boosting the flow than a big heavy wire that then restricts other uses once it's not needed; the small wires can be reassembled, taken away, etc. A1 to B1 next to A2 to B2 can be built in such a way their energy stays to their destinations. If we have understood so much about how conducting electricity works, then we also know how to oscillate it and predict such problems you've brought up and ways around. Hope this helps.
Scott Heaton
Scott Heaton 2 aylar önce
It's kind of a chicken or the egg question. Photons and electron flow most certainly can be measured numerically and quantified. Battery reactions require those redox reactions. But the animation of the waves and resulting energy is top notch.
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