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

lol

Same

I am still confused, but at a much higher level.

😂

Lmaoooo

Holy crap. I have degrees in engineering, have investigated numerous electrical fires and worked for decades developing electro-mechanical devices, and no Electrical Engineer has ever explained electricity this way. Things now make a lot more sense.

11:32

😢09😮😮😢🎉up🎉 11:35 op 11:36 🎉o😮😮😮🎉l😮😮o😮🎉o🎉🎉😊😮

🎉 11:43 11:43 🎉ol

His explanations are trivial, and answer to light bulb problem is absolutely wrong.

I studied electronics. I learned about Maxwell and Poynting... And I passed the exam. But I never before brought this (and it has not even been mentioned in all the lessons) into a context with the flow of electricity, specifically with DC. However, having heard about the basic formulas and theorys it became clear very fast ("flash") :-) Thanks for this explanation here...😄

He basically theoretical physcizied our asses. Did a thought experiment and made a prediction

@L Tam what's the prediction

This video should be mandatory curriculum for people trying to obtain Magnetic Particle Testing certificates. This explanation would have made the class so much easier.

When I got mine in the 80's there was NO mention of anything remotely like this. And I did MagPart/NDI on Acft assemblies for years.

Actually it's more of Conductivity Testing which is what this says all about.

@Jon Taylor the explanation of the right hand rule and flow of current, where the field lies is specifically as well as rectification or the capabilities of DC vs AC is what I was referencing. And the theory of electricity helped my understand the why. I’m a very curious person and knowing the how or why helps me out. Maybe not in the field, but certainly for the written testing I took. I understand that this may have not helped everyone, but I had to get my certification online when I inspected Railcars in a repair facility. It was brutal because there was no way to ask questions. The test was literally a regurgitation of information. All memory. I feel like I would have had an easier time because if I didn’t remember the answer, I could have at least understood the theory enough to make a logical assumption. We only ever used Rectified AC with dry particles. Never told why…that was just a standard for our industry/company. Now I’ve got a better idea as to the why Edit: added more

I must add that Magnetic Particle Testing certificates should be a prerequisite to get employment at janitorial jobs.

I just want you to know that through several physics classes and after a decade of angrily not understanding how electrons flowing in a circle actually transmits energy, you have finally answered my question. Hallelujah, thank you for taking the time to actually explain the how instead of simply telling me to memorize equations

i have more questions now

Ima watch it again.

I watched this video a year ago, but I understood nothing because the only thing I learned in high school was that energy moves through the wire. One year later, after learning about electric and magnetic fields and induction, this video made way more sense

bro same. I just passed my master course Advanced Electrodynamics. I even made calculations with Poynting vectors myself. And yet, this video completely blew my mind.

Wow! I’m an old engineer that spent much of my career designing radar systems. While I knew that my first impulsive answer was likely wrong, it’s been a really long time since took a college E&M physics course and first learned about Maxwell’s equations and Poynting vectors. Too, no one explained it nearly as well as you. Thanks.

Well well well, stepping into my territory, eh?! I shall make a video about this!!

Hey Buddy

Gauntlet thrown! I have my popcorn ready.

من فن شمام😂😂😂 فارسیم نوشتم چون میدونم ایرانی هستین

I would love to see your take on this

yo

So in theory, if we could use a box or device to block the magnetic and electrical fields the load wouldn’t work, in this case light wouldn’t turn on? Could we get a follow up video showing that? Also would be interesting to use iron fillings to show your theory in a working circuit. I’m an electrician and was never taught this thought process! This is why I love this field, always learning. Great video, keep up the great work.

The iron fillings distort the actual fields because they to give off a magnetic field themselves so the representation would not be correct. Yes of the fields were some how blocked zero would happen. Here's the thing though, the Eather permeates everything because it is 1,000 times smaller then the smallest atom.

@marathonman  so does this have something to do with Eather Theory cause it does remind me of it.

Yes, would be interesting to put up some sort of physical barrier at 90 degrees to the wire and see what happens...

Great experimental thinking here. I believe you'll find that they are inseperable however. This video is somewhat misinformative. In transmitting energy, wires do indeed guide the transmission of power (that's why we use them) what they don't do is (fully) CONFINE it.

@daviga1 "Never try to teach a pig to sing, it only frustrates you, and annoys the pig"(Isaac Asimov)

This is really cool. I always thought of it as water because that's what helped me pass a circuts class in college, but I've always been curious about magnetic fields and stuff, so this answer is cooler and therefore better.

^circuit

Magnets; how do they work? I love that question is treated as idiotic but it’s actually a profoundly good and important and in fact difficult question lol.

Same here

@Rick MacDonald You can only explain something in terms of something else which is bound to be true, axioms (set of things which are accepted as truth). In order to explain why a rubber band contracts, we explain it in terms of electrostatic attraction. In order to explain electrostatic attraction, you must know something more fundamental than electrostatic attraction in order to explain it. I hope you can see how this is a problem, there NEEDS to be something fundamental in order to explain ANYTHING. Electromagnetism just turns out to be THAT fundamental thing, you could go a little bit deeper if you know about theoretical physics but you still have to accept something as a fundamental truth of the universe in order to explain other things. (I heard this from Richard Feynman) If my answer to this question is incorrect, please let me know :)

Thank you for the video and challenging the every day assumptions. I appreciate this 🎉. A couple of questions: Where and how did you prove that it takes 1/c? If you have done testing, where can I read more about the details of your test? How do we explain the impedance that happens in large conductors along with skin effect in AC, and the transient behavior in DC switching?

Interesting, but the wires would already have fields propagated through them, because one end is connected to the battery (i.e. capacitance). What happens if you adjust the experiment, and use two switches, on each pole of the battery, closed simultaneously? Does it change anything?

Probably not. The electrons dont care where the switch is, it only cares where electrons are flowing

I feel like a baby who just realized mom and dad don’t really disappear during peek-a-boo

😂😂😂

It's light, Joe, but not as you know it! (Or thought you knew it)

okay but they still can't see me behind the ankle-high curtains

I am not so good in physics so I have a question... So if we will remove isolation from a wire and put something iron on it (or even just near it) - this iron thing will magnetize after some time? But what I definitely learned thanks to that video is that if we put a lamp near a wire, it may light after a while. Actually, I've learned it experimentally before, but now I really understand why it happened!

putting it nnear the wire will just turn it to power grid situation being air the bad conductor

OMG, I am a poor student in science but exactly 2 days ago I was wondering how electricity travels in the wire, does it do like water through the pipe to be tapped by a switch. Your explanation is awesome. Now I am 65 and this knowledge may help me to understand Physics in a better way in my next Birth. Hats off to you Sir.

This video literally changed 3 times and I have watched every time it gets better 👍

I think, what actually matters, is the location of the switch. Think if you put the switch in the middle which is 0.75 * 10^8 meters away from battery and the light bulb, when you close the switch, you'll create a signal and it shall travel from the switch to the light bulb. Thus the bulb won't light up, until the signal reach the bulb which is at least 1/4s.

I'm a student preparing for neet exam and my teacher had discussed this in Allen classroom lectures.... PG sir ☺️....

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

Try opening your mind sometime ?

Yes, same for me. It is a new concept for me, so I am so glad about the video but unfortunatelly many questions raised that are not covered by the video...

Because it does touch on a more fundamental 'weirdness' (not really) about the universe that you didn't know about before.

@Alan Wannemaker But what if the information in this presentation is in error? How does that profit an individual to spend a lot of time and mental energy trying to understand something that may not be true. It may be like global warming, all garbage but we still won't quit talking about it.

Because he's lying. He's using misleading editing with the professors to try to make it sound like he's saying something counterintuitive. He's cheating the viewer.

Definitely expected a different answer - as many years ago I plugged my phone in to top-up the charge but my battery actually reduced! Taking my charge backwards instead of increasing like it is meant to do! I can't remember what phone I was using at the time but I'm sure it happened more than once from that device. But not since then. It's true, I plugged my phone in to charge and watched it count backwards to depletion! Pretty strange!

Did you have an iPhone?

Something shorted to ground.

10:47 This must affect offshore wind projects that depend on long undersea cables, especially if you put them far enough out to not be eyesores from shore (usually over 30 miles). It shows that the more local an energy source is, the better.

Not really. 1 : More jacketing between electrical element and support strands will diminish the effect. 2: Power transmission doesn't have the same constraints as communication cabling 3: Glass fiber (among other materials) is great for structural support and won't affect your cable that way. Onshore winds are usually weaker and more variable than offshore. The best place to get energy is where it is abundant, adjusted by the cost of transporting it to its destination. Transmission losses are pretty low these days however.

Wow…this is going to take a while to get my head around. I’m not an electrician but I did take a practical electronics course in grade school. At that time they used the water comparison.

This is a great video, thanks for making it! What if the lamp were in a sealed room? Assuming only the conductors pass through the walls of the room into the lamp how would the energy get their to power the lamp? This is going to keep me awake at night!

Great question, .... 😀great video..... unfortunately it is also my question. Please someone clarify....

Do you realize that electrical energy is a product of voltage and current? For any work to be done on the bulb, you need two things, voltage, and current. A conductor supplies these two properties. Electrical energy cannot be blocked, it can only be stopped if you cut the conductor. But as long as there is voltage and current in a conductor energy will flow.

Basically you got it. Be sure that the lamp will work. Though one can argue that the room is not sealed where the cable passes through the wall.... However you got it. It it true that current flows in cables. The rest is matter of PoV

I've watched this video several times trying to wrap my brain around it. If this hypothesis is true, then , using your setup with the light bulb, you should be able to disrupt the flow of energy from battery to bulb by placing a large magnetic field/shield between the battery and bulb.

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

No its the laws of capitalism that govern the energy flow

Nikola Tesla said energy can be free , but are we willing to

hahaha

No You can create electricity if you want Many still it to :)

Unless you own a solar panel

There’s Immense Happiness watching this video ,knowing how universe actually works and understanding every bit of it Answering those baffling questions Thanks a ton @ veriritasium

I would highly recommend “story of electricity” by Jim Al-Khalili to understand the whole concept of electricity, how it was first discovered and how over time countless other technologies were developed by the discovery of electricity

Phenomenal explanation, one of the best I've ever seen and made me exclaim out aloud more than once.

Too bad it's a stupid explanation. Just think a bit: if the electrical energy is passing only around the wire, how it can ever reach the bulb filament and make it shine? The bulk filament is also a wire and according to this stupid clip, the electrical energy should not touch it.

@Exotic Spy Travel Ya, I believe the purpose of the video was to acknowledge the role and property of electromagnetism, but he never seems to realize where his emphasis falls apart. Namely, if it was just the fields around the wire, why would the wires need to be connected to the device. We could just lay electrical lines in proximity to things that we wanted to work for that matter. Also, it is very common for humans to simplify explanations in heed of making the understanding of said concept more intuitive. Yes, the analogy often used for electricity that it flows like water bugs me a bit too but it helps for practical understanding.

This is absolutely sensible and it can easily be understood when when you look at while a lot of PCB fails today, Rick Hartley and Dan beeker already gave something about this. It's all about the space, energy travels in space not the wire, but follow the part of least impedance the wire only serve as a wave guide.

I thought I understood how current flowed in a circuit... I've been lied to in school. The actual mechanism is absolutely fascinating.

The success of the clip is just due to switching the subject... Sometimes is electrons, sometimes current, sometimes energy. I think you were told the true about the mechanism for which current flows in a circuit. Energy flow might be represented in this way (perhaps better, not sure) which is familiar to those with somewhat physics education. We can use Poynting vector and fields to describe how energy goes. Yet you cannot split water (2H20 - > 2 H2 + O2) without an effective flow of electrons. This should clear the situation.

@antonio c You do in fact split water without outside electrons actually getting in. It just needs the energy from the electromagnetic fields to sort of decouple the electrons from the water molecules, perhaps, but the whole container itself IS neutral and stays neutral. I can't think of a case where you need to electrons to physically reach somewhere. It's all in the field, made because the electrons are moving ever so slightly, at least in DC ig.. This is college level chemistry, and I'm not sure how to simplify this stuff in a comment section. But... I tried.

An explanation why most electrical devices only work with DC current would be interesting now! Probably because a lot of components have some kind of diodes built into them and therefore no electromagnetic fields can build up when the current vector points in the “wrong direction“…🤔

Of course I find this video now… around 6 months ago I got into a small debate with my electrical engineering professor over a topic very similar to this. Everyone in the class seemed to be on the professors side which I guess makes sense but then the following week our professor walks into class and tells me he thought about what I was asking and had looked into it. He walked up to the board and showed some of the similar stuff you did in this video and proclaimed I had actually been correct and my original question that countered his previous discussion he admitted to the class he was in fact wrong. This was the first time in my life I had such a crystallized idea of what someone that was truly intelligent acted like. He wasn’t upset, frustrated or hurt that his initial statement was wrong because he didn’t care about being right, he cared about the truth. I know it sounds corny to say seeing someone look for confirmation instead of affirmation changed my outlook on life but it really did. Never before had I seen some so openly question their very own view and search for the truth rather than search for what backs up their view or idea. Great video, as always

Epiphanies can be painful, but we make them so. Your professor is clearly a devout scientist! Congrats to you both!!

That’s a great story and lesson! ❤

wanting to know the truth and rethinking you own knowledge, just to find out you've been wrong is a true sign of high intelligence. 👏👏👏 thinking that one is always right, on the other hand, is not

Reminds of when I was in 8th grade I argued with my elective science teacher about bullets firing in space his argument was based on the lack of oxygen and I knew that didnt matter since they can fire under water which doesn't have usable oxygen for combustion. I also liked guns growing up and its simple firearms knowledge that the use of self oxidizing smokeless propellants was a huge leap in their development. He reacted the opposite of your professor when we googled it and I was proven right.

"Power and Logic are not related." (-me) People concerned with logic aren't concerned when they're wrong, but people use _use logic_ to wield power get upset when someone else is right - their power is tied up in being right. (Note: that's the core to mansplaining too - explaining to assert dominance, not to bring equality of knowledge.)

Well explained. Electricity is basically a mix of electron flow and magnetism that energizes the conductors.

I used to think that electrons flowed through the wires, but I eventually realized that that didn't make sense. However, I had no other explanation. This video is hard to follow, even though I'm currently studying physics/electricity, but it does give me a better idea of what is going on.

Wonderful comment. It remembers me how genuine were the people long ago. I was trying to explain how the tv's work, but many of them used to answer something like "yes, yes, but how can be so much / people be packed inside". This video could be difficult to follow for those expecting that it brings breakthrough answers - since 'packed' in a smart way, with millions of views, but imho it's only entertainment disguised as sci divulgation, and the sci-quality is inversely proportional to the number of viewers ("the impressed masses" that pretend to have understood) . I would say yet another idea about what +else+ +could+ be going on. There's also the electrical conductivity aspect. There's the fact that the telegraph cable example is wrong since it doesn't give proofs / measures. Btw, hoping to not annoy, in the present, as in the past, too many things given for granted. There's a playful saying, in plebs style, "It's all fault (of all the problems of today's world - to be intended) of those who invented the atoms". :)

If electrons don't flow then we can just drop the concept of current.

@Paul Frederick «If electrons don't flow then we can just drop the concept of current.» ---- The only certainty, out of common sense, is that something flows. So the current is there, electrons, or whatever else. Could be that it cannot be described, in suitable terms for our brains limited by the need of our space & matter analogies. To understand how much the science is impacting our vulgar world vs how much our vulgar world is impacting, requires knowledge of scientific and technological history, and quite a deep thinking. Or, in other words, is it the science to drive the achievements, or is it there to explain achievements that happened, and would happen again, without all that theory? Imho we need some epistemological genuine thinking paying attention to not get lost in abstract and sterile philosophy recitals. etc etc.

Dear Katherine, do not know if it could help, try to think in terms of Shakespeare's "What's in a name", then pass to "What's in a matter that isn't matter", and "What's in a energy". Be wary of those that pretend to know too much what's down there, in the too small to be seen or measured.

@Volty De Qua electrons don't flow like water unless they are water. But the hydraulic analogy can still be useful to visualize electricity. Just not all the time. It's how a lot of competent mechanics view electricity and it serves them well enough. So I won't quickly dismiss it myself.

Can I get an informed opinion on the Skin Effect please when it comes to audio? Does this really have the ability to impact the performance/propagation of an audio signal being transmitted down a cable? I've heard that it does, but at most it only has about a 3% effect on the signal, if that.

you are a genius for the way you teach us this. Thank you, I have learnt so much from this channel. Everyone who watches this please pay attention, this is very intelligent information.

Great video and very interesting. I have a question though: how can we explain the wireless energy transfer using this principle where no wire/conductor is involved? (i.e. like wireless charging technology transferring energy through air based on magnetic field)

Wireless charging is mainly EM induction

I'm an electrician from the UK. This theory can be proven by holding a florescent tube near a power line. It will glow. My family didn't believe me so I showed them. So glad you explained this in a way they understands fully. Thankyou. Very clever.

A total physics noob here, Im sorry if this is a really dumb question: But if a florescent tube can glow because it gets energy from the power line, why dont we get electrocuted just by standing near a power line?

@Shiraishi Chan same doubt 🧐

@Shiraishi Chan I feel its all about distance and what you are wearing. I'm sure if you got close enough with no clothing and a direct line to ground. You may experience ark jumping. Its a very good question 🤔

@Shiraishi Chan hey EM waves not harm us ( like light not hurt you when it falls / passes through you) here energy is transferred by EM waves from the source to the electrical device which receive and convert to their known energy ( electrical) When you keep a fluorescent bulb near it takes those energy which was carried by em waves Same concept using in a current detector in a wire , we actually detect the em waves around wire which have more intensity near it

There is a difference between holding a power wire and stands near it

It's really interesting. The yellow lines propagating from the battery to the light bulb are sort of like the Earth's magnetic field to the moon. I think this is really cool.

Those Maxwell equations mantioned at the beginning are actually vectorised reductions of his 12 original equations. The work was done by Heaviside mentioned later on. Interesting that it's fields that are claimed to carry the energy. Lorentz's special relaativity which came 4 years before Einstein's and passes all the same tests was rejected because he postulated an ether, which in my opinon is in fact a field and of course everyone accepts the Higgs field nowadays. Really once you drill down it bcomes clear that a large amound of what we are told is in fact wrong! Great video BTW.

It’s refreshing to see somebody that is open to friendly debate. I can understand scientists being competitive but they never killed one another.

Mr. Veritasium, This is great! I love your videos. I see here that the switch and the power supply are right next to each other. What would happen if the switch stayed where it is, but the battery was placed 300,000 km away? Is the speed at which the light turns on measured from the switch or from the power supply?

From the power supply

You should have added in the demonstration to test the circuit with a meter after hitting the breaker, simple and easily taken for granted, but would be important for someone who doesnt do any electric work. Otherwise very informative

I teach physics at the University of California, San Diego, including this very topic. Within an hour of watching this, I set up the experiment, and got the result. I have photographs of the experimental setup, and of the oscilloscope traces. I discussed the results at length with a physics professor friend, and we agree on the explanation. In fact, the load gets (nearly) the full voltage (almost) immediately; there is no (visible) ramp-up time, nor delay through the long wires (delay Update: I love the Veritasium series, and I have learned a lot from it. To respond to some replies: I chose the simplest case, which I think illustrates the point that power can reach the load without going the whole length of the "wings." The analysis link below the video covers the more-complicated case. My "wings" are 50' hardware store extension cords. My propagation test confirms that coiling them doesn't matter, as expected. My analysis is fully transient, and the circuit transits to steady-state DC over time. Resistance can safely be approximated as zero, but inductance and capacitance cannot, as expected by theory. My load is 270 ohm, roughly the on-resistance of a 50 W incandescent bulb. The characteristic impedance Z ~53 ohm, which is substantially less than the load; that's what's needed for the simple case of near full response nearly immediately (the load is _not_ matched to Z). In this case, the wing capacitance dominates the behavior. Consolidating my previous reply: Examples of subtleties: Do two electrons repel each other? (a) Most people would say yes, and I agree. But one could argue (b) No, one electron creates an electric field, and that field pushes on the other electron. This is also correct; it's slightly more detailed, and from a somewhat different viewpoint, but (a) is still correct, as well. But (c) In calculating the force of (b), we use only the E-field from one electron, even though we know both produce E-fields. To use the full E-field, we have to compute force with the Maxwell stress tensor; this is also correct. There are multiple correct views one can take. The video's chain analogy is very good, and correct. Separately, a few replies have hit on the most-direct (IMO) explanation: the capacitance in the wires provides an immediate, physically short path for the electricity to reach the load. The path of current changes over time. Your gut might tell you that the capacitance is too small, but a quantitative transient analysis using standard circuit theory matches the experiment. Special Relativity still stands. More subtleties: characteristic impedance, etc. I do similar demonstrations in class, so I happen to have all the equipment and experience ready to go.

When the first comment is the best comment.

You know the earth is flat.

@Tim Moles - 😂 that's the exact right thing to say when the scientific jargon resembles an extraterrestrial language.

So...why do we use wires? Couldn't we do without wires in theory, to transmit energy? Basically it needs nothing in between the switch and the bulb, why does he use the wire if it really worked like he explained in the video...?

No delay? Are you saying information travels faster than light, and that you've measured it?

I appreciate this video, thank you for the work you do and helping to move us forward.

He has moved people backwards, because he is Wrong.. . Electrical power, particular DC from a battery does NOT travel in the fields, but current inside the wire.

@Hugh Leyton The wire is electrics creating the field that travels inside and outside the wire. A transformer is proof that the flow isn't limited to the wire connection but it's induced by the electrification of the wire. This is why sensitive equipment requires shielded wiring or braided pairs.

@Hugh Leyton Have you ever heard not to cross wires perpendicular to each other, this is due to induction from the electromagnetic field that's generated by electrifying a circuit. I was originally taught the lumped element model for electrical theory when I was going to school to become ASE qualified. But some things didn't fully make sense, and now those questions are answered because the picture is more complete. He is describing the totality of the electromagnetic field and how it works. What was previously taught was the simplified version known as the lumped element model. His findings don't change the information that we know, but rather add to it. Giving us some more complete picture as I stated.

But it is WRONG. . The electrical energy does travel INSIDE the Wire, not by external fields, that is simply very wrong.. . . You have been had.

@Happy Home Projects Electrical Current, that is the moving Electrons INSIDE the wire will produce a circulating Magnetic field, which does not stretch very far, just mm. . . . . That is why the wires in Transformers are either very close together, or wrapped around a common Core. . . . But that is AC not DC. . . . Sensitive equipment may require shielding from high frequency signals and noise, NOT DC

Thank you for this nice video . Now I think we can just point a battery toward a light bulb and it will light and drop the wire as long as conductor's free electrons has no job in delevering the energy. Morevere, if EM wave need guide we can use plastic or rubber instead of conducing wires . Should this worked I would believe your thought .

Thank you. I love science and all things science. I have never understood this about electricity until this video. 😃

My mind is blown! Absolutely interesting. Makes me ponder what all this does to the human body and nature in the path…. Interesting

The production quality has become insane! You're an inspiration to all us science communicators! Keep it up! :)

Tommy Gaming 🅥 Agreed - this channel is my inspiration for what I'd like my videos to become.

Do you have any idea what kind of money can be made on YouTube?

@Ryan Lush Yeah I do, but still you need to build that business up from the ground. And when there, put in the effort to reinvest that money into high quality production :)

I wonder if in your hypothetical model, would vaccumn effect the energy vector?

Thanks for the video. It is amazing explanation. I still have not got it 100% so need to re-watch several times.

finally some decent science information. More on Magnetic Resonance and Magnetic Fields please

very very interesting! I wonder if there would be a delay if the bulb was placed at the far end of the lines, away from the battery source?

If there was no delay then there'd be no such thing as network latency.

Great effort. However, I still have a difficult time to understand how we get shocked if we touch a live wire if the electricity is not by transmitted through wires? Plus, is it then ok to say that if we physically don't connect any appliances ( bulb etc.) But have close enough connections we still get it turned on ? Please try to answer as I am curious. Once again love your work.

Those are a fun few questions. Here's how I understand it, hopefully someone smarter than me can pitch in. At the top of it, we need to separate 'shock' from 'fields' and 'electricity'. There are a bunch of components to shocks, since they are a single perception of many interactions. (you can get burned by electricity without feeling a shock!) There are a couple things that go on, there's electro-motive(moving electrons) forces, and fields. I'm gonna mostly go after the first, electro-motives. TL;DR, You've created a path that will guide (conduct!) electrons, electrons are already on this path and they will start to move too. This motion can cause problems, even before the external electrons move over in appeciable amounts. A little more elaborated- separate a shock into a few parts. Firstly, a shock isn't exclusively something that 'enters' you at a start point. It begins when there is an arrangement of a pathway (sometimes regrettably through us, sometimes it's already there but there isn't enough voltage to make it viable at its' resistance). If there is a sufficient path, it will become a 'wire'. You'll have a route through the body that guides (conducts!) electrons. When you create that situation and a pathway through the body becomes the 'new wire', the electrons that are ALREADY there will begin to move as well. This is how an alternating current with a back and forth motion can cause damage despite the electron motion not progressing; by invoking this same motion on the electrons on this improvised 'wire'/path through a person. This is where the nasty part starts, if enough electrons are moving (a big current), they can polarize/denature/etc SCREW WITH nerve function, which is important to things like our heart. This is a separate problem from fields, which we're actually pretty resistant to in comparison.

Speaking as an electrical engineer, electricity is the closest thing in to magic that everyday people deal with. I deal with conceptualizing electricity and electrical components every day, and you're kind of forced to think of amperes like your chain analogy, voltage like water pressure, transformers like gear boxes, etc. But you have to keep in the back of your mind the whole time "but it's not water mains or a gearbox, it's electricity". It's simple up close but a whole other different thing when you try to think of the whole power grid at once. My advice to laypeople? Learn what you can, and marvel at the physics of electricity with me! ...But call a professional if you need to wire a car charger into your garage.

word!

I can almost guarantee that the electrician who wires your car charger doesn't understand much of this either >

@nathan87 electrician here; we’re not labourers or handymen, we’re trained in electrical theory and hold technical qualifications. We may end up slightly dirty at the end of a work day but we’re well paid and quite knowledgable 😊

I am exactly the kind of person the wise man was referring to when he said "A little knowledge is a dangerous thing". I'm exactly the kind of person who would learn the basics and immediately think they could DIY their own car charger, lol. This video, and indeed this comment, are good reminders that I don't know ANYTHING about how electricity works, no matter how many cool analogies I know.

@nathan87 But he will certainly be aware of the dangers evolved with working with electricity! As the OP already quoted, electricity comes pretty close to magic: you can't hear/smell/see it, but it can kill you quite easily.

It's exciting that you've managed to sensationalize this kind of knowledge!

Surprising, I'd say

@antonio c You could say that he's brought new energy to this field

And this is the way to do ads and product placement. Thank you for it, coming from a person who hates most ads. Non-intrusive, explicit, not distractive or ignorantly manipulative, yet sufficiently in place as you use those in the video, and who wonders what they are, can find out in the end.

After watching this Vedio I understood the answer toone question that was I asked in one of the interviews The question was "what happens to the electrons at the place Where a current carrying conductor was cut with a knife while carrying current. Now I know the right answer. Thanks for this most interesting and logical concept of flow of current in an electric conductor.

I often ask myself how much science suffers from confirmation bias. Great upload....THANKS !!! I wish everybody a positive life 🍄🌏👁😀

This really shakes up my own personal understanding of electricity and how it works. I think that electricity is a triad of functioning flows of which at its core importance is the potential difference in electrons. What is an electron. The difference is life and death. Light and darkness. Hot and cold.

I think the best part of this video isn't just the information it presents, but also the conversation it sparks in the comments! People asking questions, people trying to understand what's being said, and even people providing counter-arguments in certain scenarios where what Derek explains doesn't seem to match up. I think having civil discussions helps a ton, thanks Derek + the Veritasium community! This video and the comment section is genuinely interesting to go through

People just figured out that he is wrong 🙂

@markmd9 where's your evidence?

I think he is being somewhat intentionally deceptive/vague in the video on purpose to cause this :P He's not wrong, it's just a weird perspective.

@markmd9 He is partially correct and partially wrong. There will be some small energy transfer between the bulb and the battery in 1/c but the bulk will happen after more than 1s.

If you broke the circuit at the far end, 1 light second away from the light/power source, at the exact same moment (assuming 'moment' exists for this thought experiment), would the lightbulb still light up until the information of the circuit break reaches it? Or would the information of the circuit break reach the electric field at the power source immediately?

It would "light up" (slightly) anyway, but after the information gets there it would turn off. Information cannot travel faster than light after all. See the newer video Veritasium made on the topic.

Interesting! So the motion of electrons in the cable is more like cilia in the lungs expelling objects, or a millipede's legs passing along grains of sand, or maybe a sweep rowing crew pulling a fancy maneuver. I am often attracted to your videos, but this one really sparked my imagination, thanks!

It's like those balls on string desk toys, a Newton's cradle. You swing one and the other on the other end swings away. Like charges repel and opposites attract. Electricity always wants to seek an equilibrium state. That's why positive charges go to ground. But electrons are actually negatively charged. So conventional current is backwards from what's really going on. We need to make it all as confusing as possible after all.

Great video but I have a question. When the basic circuit is connected 6:14 battery´s electric field that is neccesary for the energy being send through space is extended through the circuit at the speed of light. So in theory you have to wait for the field to extend before you recieve energy right? That would mean even if you have battery and light bulb next to each other you have to wait for electric field to extend through the circuit (Wouldn´t the answer to your question be 1 second?)

I wish we were taught this in physics class

this question is always coming to my mind, and never I can find a satisfied answer ... Thank you so much

The part about AC was mindblowing. The Poynting vector is S = E x B but if both E and B are reversed, then S = (-E) x (-B) so the energy flow stays the same!

For me, that was one of the only parts where I was like "oh, yeah, I know this one!" ahahah! Everything else was mind-blowing!

The visualation was the only why I would have understood that concept. Seeing the diagram, I immediately recognized it as just rotating the circuit along the axis. People who can look at numbers and gleen the same information are wizards as far as I'm concerned.

I absolutely read SEX the first time I saw your comment. Had to do a double take, lol.

wat

@Francisco Power same lmao, I'm still shocked for everything else, I guess I have to watch the video a few more time

could someone explain how this interacts w' more than one object, for example instead of just one light globe, add a resistor linked in with 2 or 3 light globes and say a speaker. i see how it works and it makes sense I'm just having issues visualising it w' multiple objects in the circuit. thanks for the vid tho really usful, i may only be doing a level 2 in electronics but it still fun to dive a little deeper sometimes :)

I think it was My Dad’s high school experiment or perhaps college in the 50’s as a electrical engineer to light up a light bulb by winding copper around a long six foot diameter drain pipe if I remember correctly it was like 50 feet long . He then placed the drain pipe on the ground under those very tall high tension electrical towers . The light bulb lit up . He told me that anyone who claims they understand electricity is wrong . There exist phenomena we still don’t understand about electricity .

This is a very interesting. As a HiFi Enthusiast some of the thing I hear about cables suddenly make sense. Since no electrons are transferred it must happen in the electric field. But if I connect a Current Clamp over both wires. Then I won’t measure anything. The magnetic field created by the electrons in both wires will cancel itself out. What am I missing?

So if we cut the wire somewhere in between, do you think bulb will still turn on? Just curious if it’s electric and magnetic field around then a small cut shouldn’t matter as you suggested as well.

Love the question. if the gap is small enough or the voltage high enough you may see sparks - the symptom of energy jumping that gap. a continuous spark gets called an arc. needless to say, it will impede how much power makes it to the bulb, and may damage things as well.

As daviga1 said an arc can form. Effectively and ultimately a flow of electrons........

This is a very late question, but what about insulation? Does the insulated line limit the surrounding flux of electromagnetic energy? Does insulation limit the energy to limited area surrounding the wire itself?

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.

Nice

Wow u still study Great grandpa ji🙏

@Abhinav Thank you. I love electricity in all forms. Except, of course, the CHAIR!

@Backlash do chairs really exist though

A coupe of things I don’t understand: if electricity creates a kind of ‘aura’ around the wire, why are cables insulated? Presumably, this doesn’t actually insulate the electrical charge. So is it there to stop other types of signal (radio waves?) from interfering with the signal? Secondly, what about circuits scored into silicon wafers? In this case, the signal must travel via elections due to the small size of the signal path? Or do circuits like this create electromagnetic auras of their own?

A follow-up experiment should change the distance between the battery and the bulb and plot the time it takes for the bulb to light up as a function of that distance.

I believe the bit about the Energy being in the fields, but if the 1/c answer is correct and hence the field can propagate straight through space from the battery to the bulb without having to go along the (long) wire, then this begs the question as to why the wire is necessary. You should also be able to set up a sort of „quantum erasure“ type experiment in which at the far end of the long wing loop the wire is cut through after the light bulb lights up, but before the information that the wire is no longer connected could travel or be seen at the bulb. So what happens if you connect the switch and then severe the loop at the far end at a time t 1/c< t < 1s? And when would the bulb extinguish? If it extinguishes in time less than 1second then you are successfully transmitting the information as to whether the wire is severed faster than light. you could use this to make a faster than light morse-code transmitter. Please rebutt.

It's intriguing and counter-intuitive. What if we place the light bulb inside a box shielding all EM waves?

At the end of a very intese physics course and right after the exams, our teacher ended it by telling us that everything we had just learned about the flow of energy in an electric system was most likely wrong and mentioned something about energy not passing through the cables. Now I finally know what he meant. Thank you 😅🙇

What are the cables for then?

@RocketPig I might be wrong, but I think they are essentially allowing the magnetic field to form properly in the loop configuration and essentially becomes the structure the fields will form around. So for example, without the cable, you can't turn on a battery or switch and just power your devices, it needs a bridge to stabilize around and focus it's energy into. But maybe I am flat wrong, but this is how I am kinda understanding it

@RocketPig I believe they are to transmit those fields to your home, otherwise they'd disperse. I'm actually dumbfolded by what I just learned.

I do remember thinking it was weird that a ring voltometer could work at all, If the coating of wires was a good enough insulator to protect me, why would a voltometer work at all? I won't pretend I've fully grasped the info in this video, but it does help me realize the importance of the field itself.

A teacher saying everything they just taught you was wrong is such a baller move, honestly. That's how you keep people curious.

Your video is excellent thank you, You're a great teacher

Dang. Can't say I ever knew or even heard about that. Is this also the reason why there are so many new health problems that are acclaimed to come from Electricity? Or are those more likely to be caused by Radio waves and whatever Bluetooth and Data uses?

Subscribed. You're a gifted orator. Great stuff.

Such a well done video that I listened to the whole ad at the end. I dislike ads but so appreciated the information.

Very good info. I worked in the electronics/semiconductor field all my life, and confess that I always thought of it as flowing through the wire, or on the surface of the wire, when I gave it any thought at all. Of course, inductance in transformer coils are kind of a heads up that energy in transferred through the EM field in space, not wires. I suppose the wires could be thought of as the necessary scaffolding for the EM field to propagate and transfer energy.

I would be ashamed to mention I have experience in electronics and fully agree with what is said in the clip. "Of course, inductance in transformer coils are kind of a heads up that energy in transferred through the EM field in space, not wires." You're missing the big picture. Think about the transformer example: - an AC power source generates an AC electric field; - the AC electric field pushes/pulls electrons inside the primary coil of the transformer; - the flow of electrons in the primary coil creates an AC electromagnetic field (and other effects, e.g. heat); - the AC electromagnetic field pushes/pulls the electrons inside the surrounding coils, including of course the secondary coil; - if we connect some kind of electric load on the secondary coil, then we can say we have a transfer of energy through EM. However, that energy is not coming over the air directly from the power source. It is ALWAYS coming through the flow of electrons. "... and confess that I always thought of it as flowing through the wire, or on the surface of the wire." If all the energy is transferred through the space outside the wire then why high power transformers use thick wire and small-power ones use thin wire? If the electrical energy is not traveling inside the wire then why the bulb filament (which is a wire) gets hot when connected to an electrical power source?

:) I would say yes, wires act almost sort of as a conduit for fields to propagate in (especially in a 2-conductor based system where TEM fields are possible). While fields will propagate in all directions, there is some truth to energy flows in the path of least resistance. And hence energy distributes differently depending in the medium it is propagating in.

I’ve been an electronic technician since the 90’s and I remember one of my electronics instructors explaining this to us and it still blows my mind all these years later. Fascinating video, thank you for posting.

Suppose the bulb in the diagram was at the middle of the top line of the square of wires would the field arrows that were in the diagram still move towards the lightbulb?

I think it is a bit easier to picture when thinking about microwave Radio Frequency (RF): they literally have wave-guides that look like steel pipes. From the shapes of these "pipes", it is clear that all the energy is in the empty space inside the "pipe" rather than in the conductor on the surface.

I am not convinced. I think the E field needs to propagate along the wire to have enough intensity to light up the bulb. Otherwise, if I disconnect the bulb from the wire, according to the video, it seems the light would still be on, which cannot be right. Would you might help me understand this?

Can you explain something? When I switch my house light on, what distance is taken into equasion? From lightbulb to nearest transformer?

@Yogurtmaker From the switch to the light.

I am a grade 12 science student and I found this video really interesting.

I think this is a well-produced video that jumps to both right and wrong conclusions. Okay, energy is transmitted by the electromagnetic field. But the electrons passing through the wires play their part. Otherwise, a broken wire would conduct energy just as well as a good wire. Maybe I could agree with your answer just because of the capacitance of the proposed system, but as a RESIDUAL energy transferer.

And at UHF frequencies, there is a phenomenon called skin effect. In electromagnetism, skin effect is the tendency of an alternating electric current to become distributed within a conductor such that the current density is largest near the surface of the conductor and decreases exponentially with greater depths in the conductor.

Thank you Veritassium. This is indeed the element of truth.

Well, while we are picking at things, my HS math teacher would slap us on the wrist if we said "over" because that is not a math function. We were required to say "divided by" since that leads to better understanding. That has stuck with me for over a half century. Cool presentation.

I think one of the most difficult things about the Poynting vector is to visualise the cross product in your mind. That video with all fields represented in space is extremely helpful and should be shown in EM courses.

The poynting vector visualization is wrong though! Vectors are much closer to the wires. Unfortunately a misconception in this video

@marvinalbert not wrong, just not 100% to scale is what you meant.

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

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

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

Deeply intriguing. But why does a person only get shocked when he touches a circuit's conductive wire or a battery terminal? What happens then? How far outside the conductor do the electrical and magnetic fields extend? Why is there no effect if you just come into (or near?) one or both of those fields? Thank you for the video but it's taking me some effort to get the whole picture.

Is there a way to use this electricity / power from the magnetic field without touching the wire? Could you put an LED yard light (on a wooden pole) close enough to the overhead wires - that lead into my house - to turn it on? It sure seems like I could and I am going to try it.

You can induce a current in a conductor from the magnetic field generated by flowing current. But that current has to change, or your pickup conductor has to move. There has to be some movement between your pickup and the magnetic lines of flux. That's what transformers do. They couple currents. When you apply alternating current to one winding it induces a current in the secondary winding. The two coils are galvanically isolated though. Unless it's an autotransformer. Magnetism obeys the inverse square law though. Field strength drops with the square of the distance. Some overhead wires carry very high voltages so be careful. You might want to watch some videos of high tension wires being discharged. It is sobering stuff.

Everyone seems to have wireless chargers nowadays so you do use such a system. Nothing novel about it.

I have a question. In many applications, we use special cables such as MI cables, super screened cables, which do increase the SNR and better /more current. How does that happen?

Very well explained, thanks

So how does Coax and similar signal transmission line fit into this considering it is so effective though it purposely uses a grounded shield? That sounds a lot like your trans-atlantic cable example, but with the opposite result.

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.

Nice story

Lol that's amazing.

Wow

A colleague's grandparents, living on farm land in Belgium, would dress up on Sunday to watch television, thinking the presentator was actually talking to them and did see them.

I have a friend who turns off the switches on all his unused power points - not because of safety, even though that's sensible - but because he believes electricity pours out when there's nothing plugged in, wasting his money.

The energy is extracted from the movement of the electrons at the load. It doesn't matter which direction that the electrons are moving, you can rectify it.

I'm so chuffed I got the right answer and could understand this, school served well - thank you Mr. Evans.

I have a question, as the electrical and magnetic energy travel in space, since they're in phase, a moment occurs where both the Elec and Mag fields are 0, How does positive energy re-emerge from 0? I always thought that the peaks would be 90* out of phase, but it is said to be in phase. How is this possible?

Okay, but If I stood at one of the lines extremes with a pair of scissors and cut the line, how long would it take for the light bulb to turn off? Would it take half a second for the collapse of the electromagnetic field? Or would it happen nearly instantly? If its the latter we could use a switch to transmit information nearly instantly over astromonical distances. If its the former then I'm confused as to how the field propogates to the lightbulb near instantly.

Should have mentioned Stinemetze was the key to designing the waveguide wire also known as a low loss Coax cable. Very important person in History!!