Really loved the ways you guys bounced off the questions, amazing discussion! :D I mostly agreed with your point, but I'm wondering how Mehdi believed the charges pushed each other since you seemed to understand the point better. Would the charges not have a backwards force equal and opposite to the forwards "pushing" force, unless it has something to do with the density of the charges throughout the wire?
that doesn't entirely sound like it's coming from the heart, reading between the lines, seems like you wanted to say something like ... "where's all the great discussion we had, you cut out most of the intense bits and only left ones that dont look too bad" hahahaha .. just kidding (partly) .. you guys are both awesome after all and i learned a lot watching both of you.
@@axbs4863 if the forces were equal and opposite, you would have no voltage difference or current flow. Potential is by definition, unequal and unbalanced, which causes movement.
The amount of respect you show Derek is really admirable, it is so easy for people (me included) to reject ideas that contradict our views. Props to you for looking into this with genuine interest
While I agree with you I think it's a really sad sign of our times that mutual respect amongst educated people seeking truth invoked great respect instead of it just being the default expectation.
Well Derek IS falling into a trap and he is wrong wrong wrong about that surface charge distribution. But that is no call for disrespect. The man is brilliant. I just happen to know better because this is a trap I fell into myself, and have put a lot of thought into how to effectively teach because it is a common mistake arising from how we teach electrostatics.
@@Tanimation_actually….I am pulling my explanations right now….I am….now almost 100% convinced that I was WRONG😅…. I am about to learn something fundamental from Derik that I can’t believe I didn’t know…I think there can only be a charge gradient on the surface….I think he is right!
While getting my undergrad in EE i was always conflicted by these questions. Then when i started making semiconductors(TFTs) it just clicked. Conductivity is determined by either electron density or electron mobility. The electric fields are what is providing the work. Moving electrons create more fields which increase the fields hence why we have propogation delay in signals. High electron mobility means the electrons can follow the fields longer before crashing which means higher conductivity.
Yes! I've been working with semiconductors recently too and studying the actual Fermi levels and statistics of various materials and material boundaries makes things so much clearer.
Not really sure what you're saying about moving electrons creating more fields causing propagation delay (eddy currents? Inductive phase shifting?) But I have a question that is irrelevant. I'm actually working to finish my undergrad in EE. Four classes to finish, but I had a spinal cord injury so I can't move anything below my shoulders really now. I was thinking power would be a good field for me, I'm just curious about semiconductor manufacturing. Would I need to use my hands for that? What about graduate degrees? I'm trying to figure out the best way to go so that I can do engineering work solely on computers.
I really love how one video by Veritasium triggered this whole peer review and productive discussion process. Especially because we, the audience, normally aren't shown that incredibly important part of science. Being wrong, or just being misunderstood, and needing to elaborate. Discuss with fellow scientists, come to new conclusions, and be able to explain better than before. All we are usually presented are the conclusions that remain at the end of this process. Not this time. Veritasium, Electroboom, Steve Mould, and all the others made this so much better than just explaining a physics problem, by showing us how scientists interact with each other. Thank you!
No, all this taught us is that a bunch of engineers (even people with masters in EE) learned a incredibly simplified model of how electricity works, and because it always works in the day to day things they assume it is the entire answer, Steve and medhi both stepped into a conversation they both were vastly uninformed about, the stuff Derek is talking about isn't some hare brained shit he pulled out of his ass, it is the _accepted_ way electricity works within the physics community, just because Derek made some missteps in presenting the info doesn't make him wrong.
@@CoreStarter Ok, but that's more or less what I wanted to say. I never intended to say Derek is wrong, I just wanted to say: We rarely see the process of how scientists further each others knowledge. Sorry if I didn't make this clear. And thanks for the answer ;)
@@robins7357 If this is how you think the scientific method and peer review works ... **facepalm** Please read about it, maybe as a starting point just about the terms on Wikipedia. Friend ... it is so easy, we have Internet!:) (Hey ... studying the basics, before making assumptions out of the blue, is also a very important part:)) )
@@dieSpinnt I'm aware that actual scientific peer review works differently, that's not the point I was trying to make. I didn't want to say this = peer review, I wanted to say we see criticism that is addressed in a productive way, which is rarely shown on youtube, and it's similar to peer review in that different people try to constructively criticise the work someone has done, with them in turn getting the chance to up the quality of their work because of it. Sorry I didn't make this more clear, but english isn't my first language and sometimes finding the right words is complicated. (Awesome user name btw, fan of the character :) )
@@robins7357 That's a absolute valid point. Oh and excuse my "Robin-Review", that wasn't nice or valid either:P Important is to use the right tool for the right job. As described by Corestarter, there are several levels of "insight". SRT won't help wenn building a house. Kirchhoff is good for day to day electronics and bad for driving a myon detector. BTW I am sad to say that "Jadzia Dax" (the one with "a") is dead.... :(
Probably a whole lot of us older nerds remember literally being taught to think of the wire as a tube full of ping pong balls (or marbles) pushing each other through a tube. I'm sure at least a couple of our teachers understood this as a *model* through which to visualize the process, but lots of them and us (including me back then, I'm positive) took it as an actual description of what the electrons were doing. Kind of how most people believe atoms are tiny spheres with tinier spheres rotating around them.
I see it more as the ("positive") holes between the (negative) balls propagating through the wire (in the correction direction, from positive to negative).
Of course the reason that positively and negatively charged particles push and pull on each other in the first place is the existence of the electromagnetic field. Or rather, these forces are described by the electricomagnetic field equations.
There's no such thing as actual explanation of what electrons do. Science builds a model, the model needs to fit experimental results, no definitive link to "the fabric of the universe"
Lol 100K views in few hours, Stunning what he created on here, just stunning, If he only talked deeper into the electro magnetic world he would have a cult following, guess he doesn't need that headache Lol
ElectroBOOM just gave us a master class in how to conduct yourself as a scientist as well as a person. He wasn’t afraid to admit when he was wrong, was open to ideas that seemed to contradict his own, but also stuck to his guns and was able to incorporate the new ideas to agree with his already established ones.
It was as you say, a master class interaction and I loved it. As to the topic, I've got degrees in both physics and also EE (semiconductor focus) and in my opinion it is still worthwhile to explore some of the basics in areas such as what they discussed as there are likely flaws in some commonly held views on how things really work. If more scientists would approach a debate such as these two, humanity could progress much faster.
Amen, how real science is done! i grew up with the same notion that electroboom had (and had to suffer the period where our instructors changed to positive hole carriers instead of electron flow or negative flow- i thought that was stupid and constantly battling young engineers that grew up during that period!)
Derek didn’t contribute much to the thought process, he just read 1 paragraph he saw in a textbook. That’s what he based his video on, and that’s what he read now. No analysis, really. And then he wrote to the author of the book for more info 😂😂 and the author didn’t explain beyond saying that ‘clearly’ they don’t move. Something seems off w veretasiums analysis or lack thereof. Electroboom, in the future I would talk to the primary source for more info, find a scientist, wouldn’t be hard. Otherwise you may find yourself in a loop w Derek greater than the one in the experiment.
@@shinsoku9128 you know that people are allowed to be interested in different things, right? I don't understand this idea that someone with a 3D printing channel cannot watch a channel about electronics. Myself, I'm interested in electronics, mathematics, physics, painting, comedy, home improvement, and much more. If you saw my list of subscribed channels, you'd know the different things I like, but certainly one doesn't preclude me from enjoying another.
It's important to distinguish high frequency current from DC current. It's the high frequency field current (coming from the switch action) that flows on the surface of the wire (skin depth phenomenon) and propagates through air on a shortcut to the light bulb. This is why a smaller potential is seen first before the DC field current makes its way around through the bulk of the wire.
This is also why there is a different effective resistance of wires for AC than there is for DC. For DC in the steady state, the current density flows uniformly through the wire, and you can determine the resistance, just from extrapolating material resistivity, using the definition of resistivity to adapt to the conductor size. For AC, there is a concentration of current on the outside due to the skin effect, such that for wires that are about 50 mm^2 [#1/0 AWG] and larger, there is slightly more effective resistance for AC circuits than DC circuits using the same wire.
Late comment, but this thread was itching a scratch that was burning through both their explanations. It's instructive to look at HVDC lines. en.m.wikipedia.org/wiki/HVDC_Inter-Island (Go to the Technical Description section and scroll down for an image of the cable.) The core has strands but they are thick. DC is much more like the analogy if water flowing in a pipe. You have a high pressure source and a low pressure sink. The net flow will be in average in a specific direction. With relative uniformity relating to the flow of charge through a cross section. When a strong electric field is applied you have atoms reaching an excited energy state and electrons move to a higher valence position. And become mobile in a stabilized field unchanging electric field.(DC except for the dynamics related to the circuit turning on or off.) Looking at AC, energy is transferred in a much different way, through the vibration of charge back and forth in a wire. Then nature of the changes in the electric field lead to more electrodynamic qualities. You can see this in a cross section of a transmission wire for HVAC en.m.wikipedia.org/wiki/Submarine_power_cable In the HVDC cable the conductor is the center core and the insulation keeps charge from leaking. There are also steel wires to provide the cable structural strength and protection. For the 3 phase HVAC you have 3 coaxial setups where there is a core conductor, a uniform dielectric, and an outer conductor. This design helps contain the more chaotic and dynamic electric field. In fact, the dielectric becomes as important as it affects the capacitance of the transmission line. In the AC model, the movement of charges is much more chaotic. This can be explored further but much of the questions about the electric field set up in a conductor by a battery, dynamo, or ac generator can gain insight by looking at the differences in construction of HVAC vs HVDC cables.
This has been one of my favorite RUclips “dramas” to follow. Amazing conversations and perspectives from many parties. I studied conventional and electron theory in college but I feel like I have learned a whole lot more from this “series”. I love it.
@@TriThom50 No, this is outside of both of those theories. Electron theory suggests that energy is transmitted from the negative leads, and conventional suggests that the positive lead carries the energy. There’s a lot more to it than that but that’s the gist of it.
@@ThaScruffShop are you talking about with current in terms of which way the charges are actually flowing? Because that is something different than energy, and this video has nothing to do with that topic. I assume you are talking about something else, and that was never mentioned in my degree.
The issue with those kinds of questions, is that they are overly simplified. Which always leads to endless discussions. The discussion perfectly shows that as well.
This is always a break point with scientists and engineers as well. Electroboom has done this in the past where he uses more simplified equations because for general use, they work. Scientists want everyone to use diffy q's to find the exact answer. Great but we don't have time for that on a project. We use simplified equations because on macroscale, it works.
@@ganon8835 I was gonna say, i literally just reported the bot and then i read ice bread's response to it as if it is an actual person or it making an actual point. Then again, i didn't click on the link, as i refuse to click links without proper context as they're _almost_ always some scam or lame unrelated video. (as i found out in the past when it was new). So idk, either ice bread is a bot as well, or just didn't pay attention and probably also did not click the link, unless the link was actually relevant, then the commenter just did a poor job at communicating it, because saying "finally it is here" is exactly what bots say. EDIT: well, there's more bots than users at this point... _ELON?!_
was about to say the same, i totally agree Enthustic people are no specialists Heck even specialists have no answer that is 100% right Just look at the equation, do the math, and thats the end Math is way nore precise than any words can be
This is tremendously interesting and I love the more in-depth, nuanced electrical discussions. This video was edited very well and kept everything understandable, great visuals.
I could understand more before I saw this video! I think that the explanation with "push and pull" and the one with electric field are equal, because they are just different theories representing the same phenomana. But, I think using electric field to understand this is better, because field can represent the situation more correctly where all the electrons contribute to the field and are affected by it, which mean this explanation include all the objects, electrons, protons and a battery, whereas "push and pull" theory only consider close particles as approximation. But, still they are the same!
I have been following this discussion for a while now and it's nice to see the both of you reaching a unified outcome. It's all about education! My Grandfather use to always say, "If you don't learn something new everyday then it's not worth living."
Cool grandfather. If you ask me that's how you keep your brain working; by using it. Plenty of research supports this, and as such, I'm fairly confident that it is basically true. my own observations would be consistent with this as well. obviously thinking all by itself, isn't going to cure some major neuro-degenerative condition, but we know what we're talking about Peace be upon you, sir.
I always thought of electric current as free electrons being pulled in sync by the next electron's increasingly +ve nucleus as its electron moves away, to be replaced by the incoming electron. Not completely in sync due to the electrical imbalance signal travelling at a fixed upper limit (C, speed of light). -- Batteries work due to the imbalanced nature of many chemicals, some relatively positive, some negative. Separate +ve and -ve chemical using some insulating boundary in a battery and connect a conductor from +ve to -ve. Each -ve electron is PULLED to the positive side, with each subsequent electron playing follow my leader. -- Vibrations between close-packed (semi) free electrons travel at C.
Where the field point of view DOES matter in EE design is when looking at PCB design, particularly where the return current flows in a circuit trace over a GND plane below (particularly for higher frequencies). The current associated with a changing signal (e.g. a pulse through the trace) in the GND plane is actually right below the trace, as it is caused by the changing field by the trace. So even if the trace meanders and zigzags all over the PCB, the return current to close the circuit through the GND plane does not choose the shortest path between the contact points, but also follows a meandering zigzagging path as dictated by the field, which follows the path of the circuit trace. Further, if you imagine sending a pulse through a trace, through a load, and then back through the GND plane, the pulse does not travel in a circle out to the load and then back through GND, like a marble on a marble track, or like water through a hose. Rather, as the pulse starts traveling along the trace, AT THE SAME TIME an opposite return current starts forming underneath the trace, traveling in unison with the signal, until it reaches the load. This is exactly like the Veritasium thought experiment - current right under the trace in the GND plane starts flowing right underneath the trace, in parallel with the changing signal. Robert Feranec has a few very good videos on the topic. ruclips.net/video/4nEd1jTTIUQ/видео.html For me at least, this was really a mental switch where it "clicked" - the intuitive idea of "electrons pushing through wires", or even, kinda like water going through pipes, didn't make sense to explain what's actually going on, but thinking in terms of fields, and where those fields are, does really help to understand. This is hugely important when designing HF or RF PCBs, and for EMI compliance (and yes, even an 8Mhz ATMega is high frequency, as the clock edges change within nanoseconds, i.e. 100s of Mhz with harmonics in GHz range).
lost me; fact is, perhaps that ain't hard to do. It sounded like you knew what you were talking about though... and for some reason, I'm going to read what you said about 10 times. Good job. peace.
So would then a "newton's cradle" model work for the energy transfer? At the speed of electrons through a material, the newton's cradle pieces interact and the interaction between the fields carries the energy in reality. Then after "hitting" one side of the newton's cradle it would slowly push the whole assembly to the direction of energy transfer and kind of explain electron drift?
The water model can still be used as a description. One must only not make the mistake of taking an empty pipe for the description. The parallel propagation of the electric fields can be described in so far that each pipe is basically filled with water. As soon as water is added to the outward pipe, the same amount of water flows back on the return pipe.
We need more of these kinds of collabs between science communicators on RUclips! Seeing these sort of back and forth not only allow me to better understand whats going on but also contribute to the scientific community and encourage public discussion of topics that otherwise would go over my head
The analogy I use is each electron is a man with a bucket in a bucket brigade and the water is the electrons . when not connected to a battery the buckets are full of water. when connected to the battery the chemical energy strips electrons from the + conductor or in the analogy empies its bucket into tbe electorlyte of the battery . the man with a full bucket next to the man with an empty one ,dumps his bucket into the empty one making his bucket empty and the next guy dumps his and so on. this in effect causes an empty bucket to move from + to - .
Yeah I think that this kind of high-quality back-and-forth is exactly the niche that science RUclips channels can fill in sci-comm. It's very much a Socratic dialogue for all of us watching. Brilliant stuff
Regardless of your views on the nature of electricity and charge gradient in conductors, *this is a tremendously important video* because it shows two intelligent adults having a civic, relevant and pertinent discussion. Very nice collab 👍
About gradient having opposite effects according to each of you, I just want to point out that in electric guitar magnetic pickups, the amount of wire around the poles DOES have two conflicting effects. It results in inductance but also impedance, which means that depending on the impedance of the receiving circuit the perceived output may be higher or lower. You'll find nonsensical results such as "mixing two pickups of radically different sizes will result in the quiet one dominating the loud one" (seen in the Gibson EB3 for example)
About the surface charges inducing a current in the conductor but also drifting along the surface of the conductor. If the surface charges do drift the reason why they might have a negligible effect on the current in the conductor is because of their volumetric state. If you add up all the available electron charges on the surface they will be vastly outnumbered by the available electron charges in the bulk of the conductor. So even if they do drift along the surface of the conductor their charge effect on the conductor remains the same but their energy contribution to the load is negligible.
@ElectroBOOM. There is also another information you could add to your analysis. About electrons being able to push something, you may investigate the electromigration phenomena, where electrons transfer momentum to the ions present in very thin conductors (again, as you said, it depends on what do you call push).
Just like with the Steve Mould's video your reactions are perfect for me. They are not here to prove the original wrong, rather to explain a few concepts better. I usually have similar questions as you do and you research them for me, thanks!
Thank you Mehdi. I found this video extremely helpful. After studying EE for 3 years i find it baffeling, frustrating and also fascinating that the "simplest" concepts are very much not as simple as they seem
Excellent arguments! I agree with you 100%. I can’t think of a reason the surface charges should be in bound states, and calling their current “negligible” doesn’t really help, because if that same quantity of charge were distributed (radially) through the wire as your (and my) initial mental model stated, the total axial current doesn’t change at all. Since talking to Derek about this I’ve been trying to think of any reason they could be bound, and beyond the surface charges that are intrinsic to the material interface/workfunction/whatever that should always exist and be uniform throughout the material, there’s no reason the mobile electrons can’t push on each other. The only bit I would add is that “batteries” don’t supply an electric field, they just pump electrons around in the most direct way possible, but with the thenevin and norton and whatnot we know it doesn’t matter 😁 I’m in the process of trying to set up a water model of exactly what you drew here on the whiteboard to demonstrate ohms law so I think we couldn’t be in closer agreement lol. Now I need to go watch your long wire experiment - I heard from a friend of mine that’s already watched you were able to get it properly impedance matched where Derek and I both missed the mark, so I’m looking forward to it!
My new (electon) electricity says that electricity aint due to drifting electrons, it is due to photons (electons) hugging the surface of the Cu. The electons propagate in the insulation (if any) in which case they propagate at the speed of light in the plastic, about 2c/3. On bare wires the speed of electricity is 1c. A good conductor is a substance that a photon can hug, eg all metals are goodish conductors i think. The hugging is strong if there are free-ish conduction electrons in the wire -- Cu has 2 such electrons per atom. Electons don’t reflect, they do a U-turn at the end of the wire. Actually, electons always go straight ahead, it is the surface of the Cu that duz the U-turn. If Mehdi measures the speed of electricity along a threaded rod he will find that the time taken is longer than for a plain rod, the difference being exactly the extra distance up & down over the threads. Mehdi or u should do a youtube about this. Your welcome.
@alphaphoenix compare two multi strand conductors of the same total areas made up of different strand counts. Is the current carrying capacity of the higher strand count greater and with better efficiency specifically because of the surface charge effect?
Will the water model show how the insulation on a wire slows the electricity to 2c/3? Praps AlphaPhoenix can put insulation or something on the outside of the pipe -- hmmmmm -- nah, that wont do anything. Anyhow neither Derek nor Brian nor Dave nor Mehdi nor Bob nor Nick have in their youtubes explained how insulation on a wire slows electricity. Derek did have a try -- he said that the insulation slowed the speed of the Poynting Field/Vector -- which then raises the question -- how does 1 mm of plastic slow the Poynting by 1c/3, when say over 99% of the Poynting is outside the plastic? The 1 mm of plastic will have little affect on the 1/c time delay for the speed of the induction across the 1m gap (talking about Derek's original gedanken here) -- it will add say 3/1000c sec to the time for the bulb to light -- koz the speed of the em radiation will spend 1 mm plus 1 mm = 2 mm in plastic on the 2 wires, which adds 0.003/c seconds to Derek's 1/c seconds. But, while all of that is happening across the 1000 mm gap (in the original gedanken), the speed of the electricity around the long circuit is 2c/3 (assuming that the full length of wire is insulated) (Derek didnt say). Actually, Derek did say, he said that the half circuit was 300,000 km long, & that the electricity would take 1 sec, which implies zero insulation. But, we can see that all of the wire shown in his video is insulated, the wire to & from the battery, & the wire to & from the light-bulb. And, Derek keeps saying that the distance to the light-bulb is 1 m -- distance from what? -- from the other wire? -- from the battery? -- from the switch? Derek should have said from the switch. But he didnt. Koz he duznt know how electricity & induction works. Sheeeesh! And, like i said, Derek doesnt know that insulation slows electricity to 2c/3. Double sheeeeesh!
Finally!! Great stuff! I've been teaching the "spitting/sucking electrons" model for batteries for ages, seems obvious once you've built a Daniell battery once in your life. Recharge it and look at that Zinc build up and Copper ions in the solution. The fact that the battery delivers energy through the + AND the - becomes apparent.
"Commendation from NASA for research work at Massachusetts Institute of Technology on the Earth's atmosphere and the Moon's surface for navigation of the Apollo spacecraft to the Moon.. Dr. Milo Wolff has found the structure of the electron consisting of two spherical quantum waves, one moving radially outward and another moving radially inward. The center of the waves is the nominal location of the electron 'particle'. These waves extend infinitely, like charge force. All 'particle' waves mix and contribute to each other, thus all matter of the universe is interrelated by this intimate connection between the fundamental 'particles' and the universe. The natural laws are a direct consequence of this Wave Structure of Matter (WSM), thus WSM underlies all of science." spaceandmotion
@@Breakfast_of_Champions same thing, just the direction of sucking/spitting gets inverted a few times per second. And actually the wave effect Mehdi talks about allows to explain capacitive and inductive effects in that case.
1) What Veritasium (and ElectroBOOM) is missing is that you simply cannot separate charge from field distribution. If you look at Maxwell equations there is not way to separate one from the other. The charges move because of the field, while charges are creating the field. You can't make arguments for both, and both can give you a usable explanation within certain frames of reference, but neither charges nor fields can be considered independently. 2) Technically nothing pushes anything else by touch since the only mediators of force are the fundamentals forces of nature, and since the only one that applies at lengths larger than the nucleus of an atom is the electromagnetic force (gravity too but not of interested here), EVERYTHING is moved away by the actions of the fields link to that matter. For example: If someone slaps you in the face, it will still be the electromagnetic fields in the atoms on your friend's hand that exchange energy with your face. 3) Veritasiums problem was a trick question not because it was not correct, but because our common (and the only one with a meaningful use) understanding of when a lamp bulb is on is at the steady state. If the lamp is on or off is not a matter of physics, but a matter of agreement, and commonly we agree that the lamp is on when it is FULLY ON, when the electrons go around the whole loop. This is why the this is a trick question, because he challenges common expectations and abuses the definition of what makes a lamp being on.
I love the way you do this, like with Steve Mould's chain fountain. Two people trying to prove each other wrong in a civil manner is both fun and a great way to learn! Also a great reminder that everything in science is just models to simplify and understand complex things
...and also another great reminder of how things could be if everybody was... well I don't know... what would one call it...? civil? normal? like adults with concerns and priorities that are exactly what they state them to be? Instead of the stuff you tend to find out there, randomly. I don't want to say anything bad about anybody... but most people suck. Not these people, however. Peace be upon you, sir.
Derek`s explanation of currents flowing over wires much reminds me of how currents flow through our bodies: by subtle disturbances of the charges around a membrane. It`s as if in our bodies the inside of the wires, being electrically neutral, serve other cellular functions, thus making for much better use of space and allowing for "intelligent wires" which change their properties based on how cell membrane and other changes induce changes in the ambient surrounding the membrane and the membrane properties.
I did some of this in College and I’m glad it’s not so straightforward to you guys either, I came away with the impression that mental models are for accurately modelling outcomes for engineering and the truth is for philosophers to debate.
I’d say the truth is more for scientists who create experiments and run simulations that test the different mental models (so for example, a transient analysis of current flow in parallel resistors that could validate or invalidate Mehdi’s hypothesis earlier that current self-corrects via bulk electron interactions and not just EM field propagation) to decide, but yes, I’m glad there’s this acknowledgement that these things aren’t so straightforward
I've always loved watching your videos. Growing up in a poor community was extremely difficult, and my lack of self-discipline did not help my decision making. From being a gettho child who had no high school education doomed to fail, to now finishing my higher education in computer science. I want to become a cyber security specialist. I just want you to know, you're part of my inspiration.
What I love is that they are pointing out that the accepted model (while it works very well) does present a lot of common questions which are NOT stupid and actually quite logical.
Classical models really aren't geared to give insight on the behavior of individual elections. They work well enough for nearly all practical applications, but eventually they break down and you need quantum models to get any additional insight.
@@theviolator23 Thank you! finally someone that goes to the core of the issue. They keep trying to use classical models, i.e. Drude's model, to treat an inherently high frequency problem that is outside of the scope of validity of their question, and then wonder why the results don't match with expectations. The "misconceptions" are not misconceptions, simply different models which are valid in some cases only because they use assumptions that reduce their validity to specific situations. Is like using classical mechanics to solve a special relativity problem.
@@theviolator23 My point was more that such models are usually taught without any hint as to their limitations. Personally, I find knowing such things helps me accept such models because it tells me my gut feelings are right.
@@stevenspmd Exactly. If you're taught that the model is just that, an approximation, and has limitations, then it's much easier to suppress that knowledge later on when you come across a problem that requires it. Otherwise you effectively need to "un-learn" it and it's really difficult
this was the most scientific way to comment a video: an specialist arguing (his believe) with another specialist backing up his theory with citations! just amazing
This is the internet at its best! Two minds comparing notes, both trying to improve their understanding of how the universe works, no egos getting in the way. Thank you for sharing this discussion!
You guys should really include nick from “the science asylum” in this. He made a really well animated and explained video discussing all this pretty much, about 2 years ago. He’s criminally under-subbed.
Physics grad here. One of the engineering physics questions that totally made students insane was to calculate the average drift velocity for electrons in a wire and calculating the eclectic field in a wire. Those questions were always MORE difficult for students that understood Kerkoffs loop laws and could model circuits well. Turn on a light and let it run for a bit turn it off. The average electron has moved and incomprehensibly short amount. Blows peoples minds. I was a tutor and every year every Professor would assign the problem. Students who rarely, if ever, came for help would come for help on the problem they "got wrong" they all thought they had an order of magnitude problem or problem with vector field modeling. I am not surprised that people are confused with this and ALSO get the idea that it does not matter much. We teach circuits in a way that helps people understand and use them correctly. Probably using a working modle is what's MOST important.
Awesome discussion - reading up on skin-effect in AC Transmission lines - the traditional model is quite effective in explaining so many of the practical questions around electricity…
I have a EET background, and I thought of the current of electrons in a way similar to you. A surplus of electrons in the wire close to the negative terminal pushes electrons ahead to fill holes in the wire close to the positive terminal. The longer the wire, the higher the resistance because you are needing to overcome a static resistance. If the conduit has a larger cross sectional area, i.e. a higher guage, then it lowers the resistance because some of those electrons in the matrix have the ability to move out of the way. The immediate way most people would understand what I'm saying is that the wire is like a pipe, but it is more like an inverted pipe. The electrons are moving on the surface, but the same properties hold true in that the higher guage has less resistance and that the differential gives electrons a way to overcome that internal resistance and push other electrons forward... But superconductors change that perspective for me. A superconductor wouldn't have a gradient. You can't use a DMM and measure a voltage potential across a superconductor and yet it will still carry a current. This would suggest that since the electrons are free to move through the matrix there must be some other force moving them. If it isn't the force of a gradient applied across the conductor, then the only other obvious force would be the field. If a field applies to a superconductor, then it stands to reason that the field would apply to any conductor. I think that the classical way of modeling electricity like water pushing through a pipe is still a good way to think about what is happening in a circuit for most circuits someone would build on a bench with a breadboard or a soldering iron, however it doesn't capture the reality of why and what is truly happening in a circuit.
Superconductors dont have a gradient, but they also do not require a field. All they need is an initial electron movement, and it will continue to persist.
Whatever the case with superconductors, the fields couldn't be outside it, because then it would result in energy leaks, but we know a superconductor is lossless. So whatever is happening, it has to happen INSIDE the superconductor, yes? So then how can it be wrong to say it's simply a matter of electron interactions within the superconductor?
@@greg77389 I'm not sure that's completely true. I remember bringing this up once in a physics class, with a superconductor with an induced current and an ideal pair of inductor and capacitor. The claim was that the current would continue to flow in oscillation unless there was some external force. To verify it, you could sense the field and reintroduce another field to restore whatever was removed by the sensing... This thought experiment has hypothetical ideal components, but it didn't seem to sway my instructor that you couldn't introduce a current external to the superconductor. Furthermore, I believe it is this property about the fields extending outside the superconductor that allows for the locking you see when suspending a magnet over the superconductor.
An interesting addition to the experiment: a third wire in between, in parallel to 2 wires, with a load in the middle. Ends not connected to anything. I expect it to act in the same way like the original load would, but current will die out as soon as the wave travels all the way. Effectively it would show that the initial low current in the load is propagated as a basically radio wave, until the wave propagates through the whole wire and creates a closed loop. While the initial wave spreads, it creates an effectively a changing electric fields, and changing electric fields, quoting Faraday, induce currents.
In my opinion you are getting some of it. Every electric current is generating a radio wave I believe. In reality a DC current is also an AC current just with a very low frequency. A square wave (what switching on a DC current is) is generated by an infinity of odd harmonics (as far as I remember) and there fore the initial switching on generates very high frequencies. These very high frequencies will of cause transfer energy to anything they get to and they are moving with the speed of light. It is these high frequency harmonics that gives the initial energy to the lamp I believe - but it is the main current that comes along the wire some how that transfers the main energy to the lamp. The radio pulses are actually losses as they go every where.
This description does not originate with veritasium, it is now well over 30 years old, although I am not aware when it was first introduced. The text book referenced is Matter and Interactions by Bruce Sherwood and Ruth Chabay. Despite also being an EE, I was not exposed to theses concepts/ideas until I read the 1999 paper "A unified treatment of electrostatics and circuits" by the same authors some 15 years ago. So while this is nothing new, is SEEMS new since it is simply not taught and rarely discussed.
A ton of learning from this one. So my takeaway is: electrons probably drift slowly because they end up having a positive net force forward in a charge gradient that is caused when voltage is applied, but they don't carry significant energy, fields do. Fields propagate, electrons follow and generate the fields or something, fields do the work. There's still something to be clarified about electrons generating fields and how the fields carry energy, as well as how resistance is properly visualized as fields. Awesome you're clarifying this!
These collaborations are great. Especially in the form of discussion where it's back and forth exchange of ideas and answers and explanations, which takes a lot of gaps out immediately - the follow up questions get answered or discussed right away. The ones that might be hidden from the one making an explanatory video, but a mystery to the one watching it. Great video.
16:11 i think a helpful analogy for the surfaces charges applying the force that moves all of electrons is one of those “bladeless” fans. those fans work with a fan in its base speeding up air. this moving air is then ducted into a ring. due to the viscous affects, the air that originated from the base fan imparts its energy to the static air inside the ring. this means that a small amount of faster moving air from the ring results in all the air moving at a slower rate. the most of the air is static until viscous forces move it. this is like the charges inside the wire. they do not have net movement on their own but with the surfaces charges they do move. and based on the book these inner charges make up a majority of the current. just like in the fan the originally static air has more mass than the fast air from fan in the base. also the air from the fan does also move like the surfaces charges
That's a great analogy! (TLDR at the end) Towards the end of the video, and before reading your comment I was thinking of the water pipe pressure/flow (voltage/current) analogy and came up with a simple modifier to it: -Imagine the same water pipe pressure/flow idea, but consider that the pipe is 1m (3ft) in diameter and the pipe inlet/outlets to battery/load are only 1cm (3/8"). This would explain how without 'pressure' there's no voltage, and that 'water' (electrons) coming into the pipe, nothing can leave, but they will move at a VERY SLOW rate. As AlphaPhoenix measured here: ruclips.net/video/rQIg5XeIgQ0/видео.htmlsi=sECQJgL35hNRfMf5&t=162 only 1 part per quadrillion of the wire's electrons are being moved to charge 28m of wire to 1.5V, and putting the two pieces of info together it seems that, indeed, "electrons MUST push each other to carry a current" while also seemingly NOT MOVING, but that's just because there are sooooooooo many more electrons in the wire that their movement is negligible. TLDR; Neither idea is wrong because there are soooooooo many electrons in the wires, so that that only about 0.0000000001% of them need to enter/leave the wire in order for current to flow. So yes, electrons push each other, but there are so many that they overall move veeeery slowly.
This has blown my mindhole. The explanation of how the surface charge gradient pushes electrons in a specific direction somwhow lead me to understand why sparks usually occur at sharp points. The gradient diagram for a wire with sharp end looks so amazing. Gave me an entirely new perspective.
in a wire there is no surface charge or such things electrons dose not distinguishes between surface and non surface space. it is the radiation of electrons in a magneticfield of an Atom causes and that is why it depends on the resistive of surrounding or interconnected object.
Very interesting discussion. I would really like to see this discussion extended to include skin effect and eddy currents as the mechanism behind that. Like you mentioned: a transient DC current wave must propagate through the wire to get to an equilibrium, and I would expect that the initial skin depth is very shallow and while getting to the equilibrium, the depth increases, to finally make electrons move in the whole wire.
When I first started learning about electronics I thought charges pushed each other, but after a while it didn't made sense to me, because how would it know what path to go beforehand? So then I started to imagine charges were "sucked" from the negative side to the positive side, so the positive charges were attacting pulling the charges, while they would be pushing each other as well, and the pull from the protons would guide them.... But after reading about singnal integrity and electromagnetic compatibility, I know it was all wrong lol
Just wait until the quantum magic wreckers that mental model. How did the particle know there were two holes instead of one? There is no connected battery or anything. But if you shoot particles, one at a time, through two holes (slits) instead of one, they behave differently. What the fuck
No that's bullshit. The particle doesn't need to know anything. No changes between wave and particle forms. No zombie cats. Just a particle riding a wave and hidden variables. Look up the pilote wave theory. It makes so much senses that physicist dislike it. Stories about zombie cats and multiverses sell better than particles riding on waves. That's why Harry Potter makes more cash than Electro Boom.
The back and forth on this topic makes me think of the difference between Newtonian and Einsteinian mechanics. Newtonian mechanics continue to serve us well in our daily lives, until the deeper reality has a non-negligible impact on a system. I'm very excited to see your replication of this experiment. I wonder how you will lower the noise floor of your measurements. If you're able to approach the ideal configuration, as described in your previous video, it would be amazing to see that in your measurement.
Or how quantum mechanics are generally able to be ignored, because at a macro scale they don't really do much, but in some cases they become super important, like if we build transistors in CPUs much smaller electrons will start quantum tunnelling
@@__8120 As someone put it, we're already using numbers like the Coupling Constant without even understanding where it comes from or why it works. As soon as we started getting past "FIRE. HOT." the answers kept leading to more questions and the questions kept getting harder to answer.
At the end of the day, it's just math, and we're here just nitpicking over the best words and models to use to explain it. The deeper we go, our normal language starts to break down, and does an increasingly poor job of translating the math to English/whatever For the record though, I'm more inclined towards Veratasium's viewpoint
I literally went through the comments to see if someone said this. If not I owuld have said it myself. Models serve us by simplifying the phenomenon in order for us to make use of it. Since the point is using it, as long as it works, let's use. While the more accurate description of the situation helps us wit hdiscovery and improving our technology. telling the difference between both views is like comparing researchers and engineers : Each serve a different thing but they are both aware of each others workwhile being 100% essential.
Amazing video. Now let's see how in AC, the high frequency current moves around the wires. I guess it'd be very similar to this, but with all the spice of skin effect, and the rapid polarity change.
I just commented this, that's why in a HF application, core size is important. HF requires very fine multi core so that surface charge can propagate quickly
@@mrpdude84 @hosemarino Now you both please explain how the "around the wire"/skin effect in HF applies in the case of a Bipolar Junction Transistor. E.g. the good old 2n2222 works up to 300MHz
This entire problem is one of AC. Whenever a direct current starts or stops, you get the same effect as AC. The DC only kicks in when the wave of electrons travels all the way from power to load. And I believe it was around 5x higher than the phantom power you get at the 1/c time. So Veritasium is right for maybe 20% of the power. ElectroBOOM is right about the electrons pushing for the other 80%.
Your second big explanation just literally recaps that the mobile electrons are still only moved by the outside charge, not by each other. Let alone no one ever argued originally the electrons didn't flow at all.
I CAN COUNT ELECTRONS! . Hi EBOOM & Veritasium , I work with SEMs (Scanning Electron Microscope) and I must insist that the electrons do move from the negative to the positive of the power supply actually "move" pushing each other and really moving . If this was not the case we would not get the ability to control them in vacuum using EM/ES fields or have them interact with the material they are "bombarding" . We can even measure each electrons energy and count them (almost one by one)
@@ronald3836well if they didn’t move, how come that a normal light bulb does heat up and produce light? Or how does an oscilloscope produce free electrons that literally flow onto a screen? In addition you can measure the heat that is produced by the friction of the moving electrons insight a wire.
@@eintennisspieler4259 I'm not saying they don't move (they do, but rather slowly). I'm saying it is the field that makes them move, not the electrons moving that makes the field. However part of this is just the mathematical model we use to explain the physical phenomenon of electricity. In this model, it is the field that makes the electrons move. And the model seems pretty accurate.
11:00 I remember asking this exact question in my middle/high school physics class. I also remember making a pretty big deal about it in my back and forth with the teacher, so this whole discussion is very interesting to me.
From my engineering courses, especially the ones relating to maxwell's equations, for DC the cross section of wires have uniform electric fields in terms of density. Unlike AC where the electrons concentrate in a skin surface around the conductor and therefore the electric fields aren't uniform within the crossectional area but along the perimeter.
Yea! Came here to see if anyone else is thinking this - neither* of them are taking them/frequency into account in their analysis. Btw in skin effect the electrons don’t concentrate - the current does (mobile electrons) *Mehdi did briefly
@@lawrencejob current as in the motion of free electrons, coulombs per second. They diverge because of similar charges standing still. The AC VS DC. Current or electrons, whatever is there to move. Right?
@@xDR1TeK For sure, what I was trying to say was that as far as I know, the actual electron concentration doesn’t change based on frequency so much as the ones at the “skin” are able to be much more mobile (and therefore current) because they’re not “impeded” by the eddys inside the conductor. Although I’m doubting myself now 😅 Such an interesting conversation, thank you!
@@xDR1TeK How then does conductor material change surface charge capacity? Why does the surface of an aluminum conductor have a smaller surface charge than a gold or platinum conductor if the surface area remains constant? Does this mean that the conductor material matters even though the charge travels across the surface only?
I saw a video from a physicist AlphaPhoenix putting this to the test with 1km of wire and an oscilloscope. It showed there was an immediate movement in the wire which then grew quite significantly. If I recall about 20% of the voltage measured conformed to Veritasium's explanation whilst the rest came through at the time you'd anticipate for the more conventional description. That seems a soft confirmation of the traditional theory, but seems to be exactly what one would expect with your later explanation in this video. I wasn't convinced by Veritasium's video but your explanation makes a ton of sense to me and conforms perfectly to the evidence demonstrated. There definitely is a time component one would expect from something travelling along the wire. The book seems a little odd to me. It describes conductors as just a binary thing rather than a spectrum. Whilst it might not matter to the description being presented it gave a lot of confusion and really wasn't too convincing for that reason. Your description gave a far better and more convincing argument. Veritasium's firm statement of "the light turns on instantly" being (mostly) wrong didn't help my understanding either I would say, even if it was trying to highlight the distinct differences in theory. Definitely glad I watched this, seeing the debate was very productive towards my understanding. Plus you're amazing at breaking down topics in an understandable way. Very glad for these debates.
I think the real problem with the whole debacle is Derek was trying to be clever instead of making the point in a more succinct way. I know he makes money from clicks but that shouldn't make clarity second.
I think the book refers only to the steady state, DC power. We're in the initial state of DC power, which is closer to AC power. We're dealing with changes in current, which means unequal charge distribution.
And without seeing the test I know that both ends of the 1KM of wire where very close to each other. Tell him to try it with the wire stretched out and the scope on one end and the battery at the other end. Creating electromagnetic fields in wire is almost impossible to avoid, they will propagate over and be picked up by any wire nearby.
Yea.. i saw that to.. And as an electrical engineer, the result of the test was exactly what i expected. its not really that strange. We see it all the time in circuit board with high frequency interaction. That is why we have groundplanes everywhere and link them together like every mm.
Great discussion. A bit lost in all this though is you keep showing a DC circuit in your animations and Derek did the same in his original example. But he refers to fields which have more effect in AC circuits. Such as his statement about power line transformers in his original video, that they don’t transfer electrons because it’s not a continuous wire. But a pure DC circuit won’t continuously transfer energy in a transformer circuit, only AC (ignoring pulsed DC circuits). So it’s really a bit of apples and oranges and why they are different but related science (Edison DC vs Tesla AC).
They are talking about dc circuit thou. Electric fields cause current, ac or dc. It's just with ac the electric field switches back and forth. Also i think you might be using "pure DC circuit" to mean "steady state DC". When a dc power source is first attached, I think we get a voltage impulse which basically behaves like ac.
@@matsaks Skin effect for ac is talking about current density, as in on average electrons on nearer the surface move faster than those in the center. I think they are talking about a similar "skin effect" for charge density here?
My biggest problem with what Derek calls "long range" interactions is that it's EM radiation that we call radio. In his second video, one of his sim "proofs" was that a free standing parallel wire carries the same initial weak charge as the loop, but there are two problems with that: first, it's analogous to the reflector elements in a Yagi antenna, which do virtually no work and aren't "read" by a receiver; second, while it mirrors what's happening on the far connected wire, the disconnected wire will not carry the same current as in the circuit because it is disconnected. If we were to watch that sim to an equilibrium-ish state, the (much smaller) radiation field coming off the disconnected wire would affect the circuit until it would reach its own neutral state or the circuits current would be strong enough in relation to the radiation that it would swallow that electronic swashing.
@@josephlarrybradley508 I come at this whole conversation as someone who holds the highest level of HAM radio license, not as an electrical engineer or physicist, but yeah, his two main points are "surface charge" and "fields." Surface charges are a core component in physical and radio networking because thicker gauge wire correlates really weirdly with signal clarity, so that's not news to anyone that works with cables. In that sense, he's got a point that the wire is not a tube that pushes electrons. However, when he moves from the micro to macro scale, he's making some really weird leaps of logic. Radio waves might jump a gap, but they're probably not going to turn on a light considering the amount of power NFC sensors require. As an aside, he also implied that wireless charging is sending electricity through an imaginary wire, not a manipulation of fields that burns electricity on one end to generate some on the other. Further, the isolated wire that I have the biggest problem with could easily be made into a transformer (another known mechanism) if he closed a loop on it.
@@tyhodnett3031 , indeed, the "long range" / EM wave transfer of energy only works for AC signals. AlphaPhoenix touched on how the initial behaviour is identical to that of a transceiver/transformer setup in his video response to the original Veritasium video.
@@JivanPal I'll watch that one soon. The second Veritasium video referenced it, but Derek's experiment in the second that showed an activity bump glazed over the relative magnitude of the current so I didn't watch any other experiments.
re: "first, it's analogous to the reflector elements in a Yagi antenna, which do virtually no work and aren't "read" by a receiver;" One has to be careful with this; there are constructive and destructive fields set up by the directors and the so-called 'reflector' as excited by the driven element, and these summed 'fields' create the radiation pattern. Point being, the reflector might be misnamed for this application, but, that's still what we call it.
This feels a little like the confusion that arises when observing waves in the ocean or atmosphere - it’s tempting to see the wave as a feature that moves and influences the flow as it does so, but in actuality the flow moves through the features, not the other way around.
It was really a great polite discussion. I get some additional ideas about the electrons flowing in a wire and i really want to acknowledge both of you.
I was involved in an experiment years ago regarding the speed of electrons in materials (metals). It does vary both by metal and by where you are in the metal (electrons on the surface move faster). That said faster in this particular context is a blistering 0.3mm per second (slower in iron and some other metals). If I remember correctly on the surface of silver, electron speed got all the way up to 0.31mm per second.
Actually, in semiconductor physics we see that electrons do ‘push each other’. If there is a carrier gradient, current is created even in the absence of an electric field (as shown by the drift-diffusion equations). Is there any significant diffusion current or any at all in a normal conductor, I wouldn’t know. Would be interesting to solve (numerically though lol) the drift-diffusion equations coupled with Poisson’s equation and Gauss’s law, on a 3D conductor with a potential difference between the ends. Then we’d have an idea of the actual distribution of fields and surface charges and so on. I think that in the case of a conductor, all the current inside is drift current, while a part of the (negligible) surface current has to be diffusion current, but that’s just a guess.
"Is there any significant diffusion current or any at all in a normal conductor, I wouldn’t know." There is, in both directions, in equal proportions. Meaning the net value of the diffusion current is zero. This applies to almost any scenario where there is no current on almost any material. Local currents always exist in lieu of electrons never staying put specially when they are 'free' electrons. But the overall distribution, because of its uniform probability of direction, cancels out to zero. I can't quote you right now (because its very specific a topic) how the currents in a wire under a potential difference between the ends are distributed (in terms of which is diffusion and drift, etc) but the answer is well known in the field and exhaustive text books on electromagnetic waves and Semi conductors usually contain this information. If I get the time to find my copy of it and review that section I'll gladly return to this comment with the textbook answer.
my haunch is that a different behaviour will be observed depending on the cross area of the conductor and the actual number of electrons. I think things change once you can count electrons (in the sense that "the system" behaves differently when you have a small number of electrons)
Awesomely FUN as well as nuanced & HELPFUL interaction between the two Wonderfully Charged Fields known as ElectroBOOM / Mehdi and Veritasium / Derek respectively !!! BRAVO !!!
The distinction of surface charges matters because the outside of a conductor heats up faster then the inside, especially with high frequency alternating current. You can't design some, especially RF applications without taking these effects, that go outside of the lumbed model into account.
I believe this video omits one crucial insight. In quantum field theory an electron is nothing more than an excitation in the electron field. When we consider an electrical current through a conducting wire then we measure those currents in Amperes. An Ampere id defined as 10^19 electrons per second (give or take a few electron). Now if we consider an average 1,5 mm^2 wire that is an awful lot of electrons in a very small area. Coming back to QFT, if we consider the waveforms of 10^19 electrons in an area of 1,5 mm^2 then their waveforms will overlap to such an extreme extend that we really cannot consider them as individual electrons anymore. All that we have is one massive excitation in the electron field and whatever that actually is, is more analogous to a massive tsunami of energy in the electron field and not a massive amount of individual electrons. Each and every individual electron really ceases to exist. So we can really not analyse an electrical current in a conducting wire by thinking of individual electrons pushing each other, but we should consider that the battery puts such a tremendous potential across both ends of the wire that we get a surge of energy in the electron field that slowly dissipates to zero as the load uses this energy surge to create work, light and/or heat.
+1 Even Rutherford in his atomic model was cautious to suggest electrons are a unit of charge and not necessarily *physical things* It is perplexing how so many describe electrons as discrete things, rather than a *model* which approximates observations in experiment.
@@stuartmacintosh4868 very well put! In the video they take the model of an electron being a particle way beyond the limits of that model. This model works really really well when you learn in school about how electricity works, but when you start analysing current in a wire and truly attempt to understand what is going on then you can't do so without considering QFT. They both take the classical view on electrons way out of it's proportion.
@@XEinstein Thanks! Yes I agree it is a common presumption that electrons are actual things, but their supposed mass is more like a 2nd order effect that Newton and Maxwell's work explains. That Rutherford model (for all it's flaws that QFT exposes!) took science as far as the nuclear age even. Basic electronics and radio can be /sufficiently/ explained with it for a working knowledge. Difficult to say this Rutherford model electronics is completely wrong, just an older (pre-general relativity) explanation.
Very interesting topic. Hope you do that test. Derek's test seemed to show that the initial voltage bump was about 4-5 v almost instantaneously and then an overshoot and drop to the applied ~20V when the main wave made it through the wire. I'd like to understand (1) if the magnitude of this initial bump is impacted by the distance between the wires. If it was 2 m or 4 m rather than 1 m apart, would the initial voltage magnitude decrease or is it somehow independent? And (2) would this initial ~25% of the voltage stay at that level or does it spike and slowly drop until the main wave from the fully wire flow gets to it. And (3) does it transfer not only a measurable voltage across a larger resistor, but does it transfer enough current through a typical light bulb type of resistance to say that it would go "on"
I always imagined it as electrons being "pulled" by the opposite attraction on the other side rather than being "pushed." In other words, once the circuit is closed, the electrons are attracted to go in that direction as there is a venue for them to go through to where they want to go on the other side. The power source is basically creating a charge imbalance on its side forcing the electrons to want to leave to a balanced location rather than them being "pushed" out. Which is why copper makes for such as good conductor, because of it's loosely held valence electrons and its outermost zone being only half filled allowing it to carry a vast number of electrons as they make their way to the other side. If that makes sense.
Really interesting discussion! I think at some point in this process of thinking about the 'reality' we have to acknowledge that thinking about electrons as discrete particles is a huge oversimplification in itself and really what we are dealing with is closer to a sort of EM-wave quantum 'soup'. Not that the particle model isn't useful; but sometimes the more complicated model makes the problem seem less confusing. I really liked your reflected wave superposition explanation of parallel resistors by the way!
"EM-wave quantum soup" sounds like an image inspired more by particle accelerator experiments than by solid state physics. Bu the latter is the right filed of science for answering how conductors actually conduct. Undergraduate E&M courses generally do not try to treat this topic, resorting instead to a few phenomenological results such as Ohm's Law. Unfortunately, my favored solid state reference has grown legs and crept away to a hiding place, so I have to answer based on memory: metals are excellent conductors because they have a "conduction band" in which the electrons form a "Fermi gas". These are the highly mobile charge carriers. The protons are stuck in a crystal matrix (yes, the basic structure of metal is crystalline -- very small crystals, too small for us to see easily). So they only wiggle and vibrate. So they do not contribute to current. So in the quasi-static approximation (which works surprisingly well even in the VHF domain for small circuit sizes) you get current from the drift (not thermal) velocities of *moving* particles but the field at any one point does not care about the motion, it only cares about charge balance. So yes, you *can* have balanced net charge with some of them moving. So yes, you can have 0 field inside the conductor, as in electrostatics and non zero current at the same time. But that, of course, is in the quasi-static approximation. Veritasium's original thought experiment does not satisfy that approximation. Worse yet, since we are talking about such long wires, it is not close enough to reality if you ignore the resistance. Not only that, but you need to take into account inductance and even capacitance as well. If this reminds you of en.wikipedia.org/wiki/Telegrapher%27s_equations that is because it should remind you of telegraphers equations. The Wikipedia article does not give the exact variation of the Equations to describe the thought experiment, but it gets pretty close: it is easier to modify one of these variations to fit it than it is to start w/ Maxwell's Equations.
After watching tons of old Electroboom videos, I finally found one that came out the same day I watched it. One of the best feelings I have gotten in a long while.
Electrons in the conduction band (a specific energy range) of a conductor are constantly moving in all directions, a gradient or field merely means that the movement in one direction occurs statistically slightly more often, but this net movement is small in comparison to the all the other movement which mostly cancels out.
I don't like the way this is phrased. Yes, the net movement is puny compared to the chaotic movement, but it's not like the random movement could possibly make any electrons flow against the drift velocity for any appreciable amount of time. The net movement cause by drift velocity is enormous compared to the zero net movement caused by the Fermi velocity.
Nicola, Thats inaccurate, a wire heats up a lot when conducting electricity, so the net movement must be significant. You dont observe heating from your random movements, meaning there is no measurable movement.
"Commendation from NASA for research work at Massachusetts Institute of Technology on the Earth's atmosphere and the Moon's surface for navigation of the Apollo spacecraft to the Moon.. Dr. Milo Wolff has found the structure of the electron consisting of two spherical quantum waves, one moving radially outward and another moving radially inward. The center of the waves is the nominal location of the electron 'particle'. These waves extend infinitely, like charge force. All 'particle' waves mix and contribute to each other, thus all matter of the universe is interrelated by this intimate connection between the fundamental 'particles' and the universe. The natural laws are a direct consequence of this Wave Structure of Matter (WSM), thus WSM underlies all of science." spaceandmotion
This is a nice eye opener. I always thought from my school lessons that electrons are flowing like a stream of water from the sea of electrons in a conductor material. But we were taught in biology that electrical charge or action potential propagates in a somewhat similar manner but here electrolytes (Na, Ca, K ions) create charges.
I am so happy I chose Mechanical Engineering in college rather than Electrical, as after watching you two's videos all my knowledge about electricity would have effed up.
Physics graduate here. Yourur material science explanations are imperfect and I learned some fancy Hameltonian math to better describe dynamics. Orher than maybe not being 100% on every detail engineers are much better trained. You actually learn how to apply stuff way better. I got a degree in Physics and get some of the nitpicks but I never learned the how to part, not like real engineers. I couldn't pass the PE exam and I wouldn't claim to be able. There's a pedantic problem with lots of engineering descriptions. There's no actual problem with not understanding some of these points. The trade off is you actually learn a bunch about how to use/do stuff.
Electrical components can be modelled the same as a mechanical components, e.g a mass on a spring and pneumatic damper behaves the same way as a resistor and a capacitor in a circuit. all engineering fields are more closely related than we think.
@@Ikantspell4 Don't get me wrong. I love these new amendments in understanding of a basic concept. And yes, as you said, the trade off is to actually learn more stuff, but I think it's a trade off (or let's just put it as a challenge) for scientists. For an engineer it's an opportunity rather than trade off to learn something new which is why the most minute of the details are of a great concern for us. Each opportunity that gives a greater output is what we focus on, as you said, with our explanations not being 100% on every detail.
@@alistairmurray626 We learn Heat Transfer with electrical analogy : Temp. diff being same as potential diff., Heat being the same as current, and thermal resistance being the same as electrical resistance, and voila, ohm's law works on heat transfer. Same analogy can be applied for flow of water through pipe.
@@aksajsharma4684 not sure I really think it's so important. Physics students like I was take E&M. In E&m we calculate and derive this stuff so it's not as much as a "gotcha" moment for us like it is for enginerds. Other than the "gotcha" moment I don't think is a big deal. Every year at my university this problem was assigned to engineering students taking physics, every year was confusing, and mostly they all went on to forget it and actually learn how to use electrical models. Here I am with a good understanding of the first principle rules but no applied skill and not working in a field where it matters. It's about time when physics nerds say " um actually the actual physical phenomenon is more like this:" The enginerds say " um actually I use this model and made a cool thing work" knowledge only adds and never takes away but maybe knowing such pedantic nuanced quirks is pretty close to useless.
Thinking about this as I get to the 12:29 minute mark in the video. If the electrons were moving on the surface of the wire vs within the wire then you could increase the amount of electricity could be delivered over the wire by either making it hollow thus doubling the surface area for the electrons move on or you could take a wire with a fractal cross section that has the same volume as a round wire and it should carry more charge. In either case the resistance of the wire should be reduced as long as the cross-sectional volume is maintained. However if either of those wires have an increased resistance to the flow of charge then we can tell that the electrons/charge is flowing within the wire itself. Looking around I see that 3M sells copper foil tape that is 1.4 mil 1" tape and that has a cross sectional area of 0.903224 mm^2 and a perimeter of 50.87112 mm and you could compare this to a wire which would be between a 17 and 18 gauge wire which would only have a perimeter of 3.369 mm. This would have to be done in a way that would allow for you to control the amount of heat that the wire is producing as this will by itself increase resistance. This brings up the thought, are round wires better at transferring charge only because of the mass and its ability to transfer heat away. Or would the electricity find a single line on the surface of the tape and run the current down that until it heated up and increased resistance on that path which would cause the current to flow down another path and so on and so forth. I do not know how this experiment could be designed but reading the data sheets it says that those wires can handle 2.9 and 2.3 amps of power transmission respectfully. Finally to finish this up we also need to think about the ability of the electron flow and if a round wire vs the foil is better at making the fields that push the charge along.
I like your tape idea. It would be interesting to try to watch current flow through the tape and wire under an electron microscope. If that is possible.
When you do the experiment, could you do parallel wires (as in Derek's) and also a circular loop? It would be interesting to compare the maximum effect vs the minimum
@Mike Foster Hi Mike, the light turns on almost immediately due to the capacitance between the wires on metre apart not from the current travelling around the length of wire. A capacitor does not have a continuous connection inside it. André
I could almost feel the temperature of my brain rise, as I tried to absorb and understand this... again. Your discussion and graphs, especially the vector drawings, helped me understand a lot better. At the end I kept thinking this is like fluid dynamics, which is very difficult to model. Thanks for diving back into this subject.
If we form a circle and all push the one in front of us every one second, are we all going around in circles? That is the difference of propagation through a circular medium vs motion in a circular path. Fluid dynamics is nothing like electricity. Propqgation of sound in fluids is like electricity. When there is motion, the scale of the phenomenon is much, almost infinitely, larger and the phenomenon is a lot more complex, especially near the edges of the fluid container. When the phenomenon is simple in its measurement. you are looking at propagation, not actual motion.
Both models may be consistent with each other, but the field approach can be “solved” for practical problems. Perhaps the particle approach can be too? But it’ll come down to fields at some level.
Yeah, good point. I think a lot of engineers learn: electrons -> voltage + current rules -> fields equations to calculate antenna's and emf. They still see the electron as the true master in this interplay. While physicists learn electrons -> voltage + current rules -> solid algebra -> deep understanding of fields and how to calculate them generally. They seem to switch to a field first model, to them the electron is just a charge carrier. It is all very interesting. Obviously generalizing but seems very clear when you listen to the likes of dave from eevblog versus some professors in physics.
@@kapytanhook I think that’s true too, or at best kept vague as to how charge carriers and fields interact (especially in terms of this electromotive force). As an engineer I felt that motors and generators are also taught from a very field-based perspective. Once we need to make practical calculations we forget this particle view! Unless the current densities are low, but that’s a whole other thing and probably at the point we neglect carrier-carrier interactions. Physics undergrads seem to be engaged with fields at a slightly earlier stage than engineers, in terms of Maxwell’s laws. Maybe that shapes our world views.
@@colinedb yeah, motors and generators are very field based. But even there i kind of kept in the back of my mind it's the flowing electrons being the boss of that field The right hand rule and such are from a perspective of the current, at least how I saw it. Currents make fields that in turn make currents again, the field being a tool for currents to interact. Like how gravity is the field that makes objects pull together, it's easy to get a bit of a particle preference because they are instances
at high frequencies in a real circuit you can't remove all the inductances and capacitances that are never thought of at low frequencies. both systems work but how it's thaught people often forget the true circuit in favor of a more ideal that works at low frequencies and normal conditions where light speed is high enough.
What I think would be very interesting for the large loop experiment is changing the position of the load (lightbulb) in the circuit. Because the field explanation suggests to me that the lighbulb right next to the battery should be significantly brighter than one far away since the fields are strongest there Although now that I am writing the field gradient might be the deciding factor for the brightness which would be constant, I think?
After thinking about it, my conclusion was that you can treat electrons as magnets, monopole magnets. so they can push eachother and transfer lots of energy without really moving anywhere. Now I don't know what to make of it, yet I did notice that the final model does explains somewhat why inductors resist to change in current.
I think this video is incredible, apart from the content that is very interesting, you can clearly see the difference between a engineering mind set and a scientific mind set. And is really fascinating the fact that by viewing both sides you can get a really good understanding of the phenomenon.
The point about charges outside the conductor is an important one for some circuits. A good example is that I learned when setting up my sound system that you want to run the power cable for the amplifier on the opposite side of the car from the audio cable from the head unit to the amplifier. The reason is the power cable draws a strong enough amount of current from the battery that the electromagnetic field will actually cause interference with the audio signal, which in turn causes "dirty sound" as a final result.
As much as I learn from your channel, these collaborations do an amazing job of helping me figure out how such seemingly simple, yet incredibly complex, topics work. Thank you, and keep up the great work!
A variation of this phenomenon happens in programming. Whenever you began learning how to code you have this weird feeling that the puzzle that is the system you are coding, gets resolved on both ends simmultaneously back and front. When I began learning reactivity I learned that "regressiveness" is a common aspect of any system, not only AI, this regressive aspect is the one that may be confused, when squinting eyes, as if information is going forward... and this is not wrong. Regresive functions leave a state change behind them as they move backwards, it is a macro backward motion, composed of micro feedbackloops on each step, the feedback left by the regressive motion is perceived as going forward.
From my understanding, your model averages out the 'reality' model, so it makes sense that would work most of the time. The few cases where this model wouldn't work would likely require to work at the atomic level and I assume this rarely happens unless you work at the CERN or something.
@@chalichaligha3234 Agree. Think about how a capacitor works. It is a charged coupled device based on accumulation of electrons on one place and electron "holes" on the other. A dielectric stress is created which creates the charge and resulting E field. In a DC circuit, a cap will charge to the full voltage applied, causing a current flow until it is fully charged. Then, the current flow stops, but the voltage potential is maintained as long as the circuit has no leakage.
This is awesome! Good work both of you... building quality knowledge for the world like that! It's been awesome to follow this discussion from the first Veritasium video throughout all the reviews and discussions. I think you did a grand work on putting the final conclusions into action! Kudos!
So on the point of when Derek's model would be useful, I'd say it has quite a lot of utility when looking at the low-level function of individual circuit components, and trying to predict measurements of them with high precision. Medhi seems to be heavily focused on a circuit based viewpoint of EM where there's only really wires, resistors, inductions, etc that all have certain numbers attached to them, and they just all kinda work a certain way when you connect them. But you got to remember, that at the lowest level, all of these circuit components act according to Maxwell's equations, and those equations all operate according to fields. And in a lot of ways, you simply *can't* derive accurate results and models of these components without elaborating the gory details.
It was surprise for me by the way that you can't accurately model real-world electrical circuits with just a combination of separate wires, resistors etc. In reality all elements are connected with all elements. To be more precise, even parts of elements with other parts of elements. Example, which I like, is that real inductor have no single resonant frequency - there are many of them. I hope that at some time people will develop better tools to accurately simulate and not less important - visualize such connections.
If you really want an accurate explanation of the way conductors and current works, then Maxwell's equations are not enough -- you really do need quantum mechanics, or more specifically solid-state/condensed matter physics. The proper explanation of the way currents flow is actually fairly complicated, but electrons don't behave as localized objects in a conductor -- they behave more like momentum eigenstates (to a certain degree -- it's complicated).
I hope it's not too late to answer. It feels like both of you are actually right. We are able to calculate the drift velocity of electrons in a wire and it clearly shows that it's too slow for the current to be carried by electrons without any other interaction. In the book that veritasium quotes, it says at equilibrium and steady state, but I don't think we can consider the wire in a steady state as soon as we close the switch. To have a steady state you must have the same values (forces, velocity, direction, etc) at different times on the same place, but it doesn't mean it needs to be same particle. Watching the video gave me the idea that what happens in the wire can be modelled like this: 1. Just like water flowing in a pipe have velocity gradient where it's faster in the middle so electrons have some sort of gradient symmetrical to the center of the wire 2. Since electrons alone move too slow, they act like a Newton's cradle where instead of using the body to transmit energy, the electric fields act as the medium to transfer energy at the speed of light Using this model, you will see magnetic fields from the movement of electrons and also the power will move at the speed of light (so speed of the "electrical field wave") through the wire
Electrons pushing on each other is the reason there are surface charges in the first place! If you push electrons into the wire, the local excess negative charge repels itself until excess charge is forced onto the surface, and the entire inside is at the same potential.
You have surface charges in a capacitator as well. Even if you just have one side of the cap, and put the other side to infinity, the charges will move to the surface, to reduce the forces between them, and thus the energy stored in the system.
@@colto2312 Is there a simple way to learn hydraulics? When I looked up courses they all wanted to start with open-system hydraulics like rivers, but I'm only interested in closed system hydraulics like lift systems in forklifts
@@colto2312 I know the basics of closed hydraulic systems but I want to know enough that I could design my own hydraulic lift I understand that a big piston pushing on the fluid with a small piston on the 2nd end means the 2nd end gets more force for the same weight, and restricting flow increases pressure and vise versa But I want to master the topic
I suggest be careful about the claim you make at 23:06. AlphaPhoenix already did the experiment at 1 Km. wire length. He did a great job, and captured the results on a nice storage scope. He showed Veritasium's claim quantitatively, with a small but significant transfer straight across at light speed, and a full transfer after propagation through the wire. He follows his motto well: "Plan A always goes up in smoke."
Great job editing our conversations! I think it represents our main points well. And the whiteboard animations make things much clearer - nice work!
Really loved the ways you guys bounced off the questions, amazing discussion! :D
I mostly agreed with your point, but I'm wondering how Mehdi believed the charges pushed each other since you seemed to understand the point better. Would the charges not have a backwards force equal and opposite to the forwards "pushing" force, unless it has something to do with the density of the charges throughout the wire?
Nice seeing you here :D
W
that doesn't entirely sound like it's coming from the heart, reading between the lines, seems like you wanted to say something like ... "where's all the great discussion we had, you cut out most of the intense bits and only left ones that dont look too bad" hahahaha .. just kidding (partly) .. you guys are both awesome after all and i learned a lot watching both of you.
@@axbs4863 if the forces were equal and opposite, you would have no voltage difference or current flow.
Potential is by definition, unequal and unbalanced, which causes movement.
I like that you both understood the question better by your discussion.
@Don't Read My Profile Photo Ok. I wont do that.
Wtf 9 hours ago?
wtf lol are you a friend of medhi or something
@@Captain_Pikachu Patreon supporters got early access
@@JustPyroYT FYI
The amount of respect you show Derek is really admirable, it is so easy for people (me included) to reject ideas that contradict our views. Props to you for looking into this with genuine interest
watashi wa Kira Yoshikage
While I agree with you I think it's a really sad sign of our times that mutual respect amongst educated people seeking truth invoked great respect instead of it just being the default expectation.
Well Derek IS falling into a trap and he is wrong wrong wrong about that surface charge distribution. But that is no call for disrespect. The man is brilliant. I just happen to know better because this is a trap I fell into myself, and have put a lot of thought into how to effectively teach because it is a common mistake arising from how we teach electrostatics.
@@pauliexcluded1right? He's completely wrong. But props to this guy for keeping things cool.
@@Tanimation_actually….I am pulling my explanations right now….I am….now almost 100% convinced that I was WRONG😅…. I am about to learn something fundamental from Derik that I can’t believe I didn’t know…I think there can only be a charge gradient on the surface….I think he is right!
Great discussion!
The goats of electronics keysight
Suppppp buddy ❤️
Im watching this while testing battery packs assemblies with your EL33133 DC electronic load, its my favorite piece of equipment in the lab
@Keysight labs Hello electroboom always talks about you and your products 😊
Can I have his scope?
While getting my undergrad in EE i was always conflicted by these questions. Then when i started making semiconductors(TFTs) it just clicked. Conductivity is determined by either electron density or electron mobility. The electric fields are what is providing the work. Moving electrons create more fields which increase the fields hence why we have propogation delay in signals. High electron mobility means the electrons can follow the fields longer before crashing which means higher conductivity.
Yes!
Can you please simplify and just say who is right and upto what extent??😅
Yes! I've been working with semiconductors recently too and studying the actual Fermi levels and statistics of various materials and material boundaries makes things so much clearer.
I think you got it, so batteries are just wave generators and conductors are the just different mediums for that wave to propagate.
Not really sure what you're saying about moving electrons creating more fields causing propagation delay (eddy currents? Inductive phase shifting?) But I have a question that is irrelevant. I'm actually working to finish my undergrad in EE. Four classes to finish, but I had a spinal cord injury so I can't move anything below my shoulders really now.
I was thinking power would be a good field for me, I'm just curious about semiconductor manufacturing. Would I need to use my hands for that? What about graduate degrees? I'm trying to figure out the best way to go so that I can do engineering work solely on computers.
I really love how one video by Veritasium triggered this whole peer review and productive discussion process. Especially because we, the audience, normally aren't shown that incredibly important part of science. Being wrong, or just being misunderstood, and needing to elaborate. Discuss with fellow scientists, come to new conclusions, and be able to explain better than before. All we are usually presented are the conclusions that remain at the end of this process. Not this time. Veritasium, Electroboom, Steve Mould, and all the others made this so much better than just explaining a physics problem, by showing us how scientists interact with each other. Thank you!
No, all this taught us is that a bunch of engineers (even people with masters in EE) learned a incredibly simplified model of how electricity works, and because it always works in the day to day things they assume it is the entire answer, Steve and medhi both stepped into a conversation they both were vastly uninformed about, the stuff Derek is talking about isn't some hare brained shit he pulled out of his ass, it is the _accepted_ way electricity works within the physics community, just because Derek made some missteps in presenting the info doesn't make him wrong.
@@CoreStarter Ok, but that's more or less what I wanted to say. I never intended to say Derek is wrong, I just wanted to say: We rarely see the process of how scientists further each others knowledge. Sorry if I didn't make this clear. And thanks for the answer ;)
@@robins7357 If this is how you think the scientific method and peer review works ... **facepalm**
Please read about it, maybe as a starting point just about the terms on Wikipedia.
Friend ... it is so easy, we have Internet!:)
(Hey ... studying the basics, before making assumptions out of the blue, is also a very important part:)) )
@@dieSpinnt I'm aware that actual scientific peer review works differently, that's not the point I was trying to make. I didn't want to say this = peer review, I wanted to say we see criticism that is addressed in a productive way, which is rarely shown on youtube, and it's similar to peer review in that different people try to constructively criticise the work someone has done, with them in turn getting the chance to up the quality of their work because of it. Sorry I didn't make this more clear, but english isn't my first language and sometimes finding the right words is complicated. (Awesome user name btw, fan of the character :) )
@@robins7357 That's a absolute valid point. Oh and excuse my "Robin-Review", that wasn't nice or valid either:P
Important is to use the right tool for the right job. As described by Corestarter, there are several levels of "insight". SRT won't help wenn building a house. Kirchhoff is good for day to day electronics and bad for driving a myon detector.
BTW I am sad to say that "Jadzia Dax" (the one with "a") is dead.... :(
Probably a whole lot of us older nerds remember literally being taught to think of the wire as a tube full of ping pong balls (or marbles) pushing each other through a tube. I'm sure at least a couple of our teachers understood this as a *model* through which to visualize the process, but lots of them and us (including me back then, I'm positive) took it as an actual description of what the electrons were doing. Kind of how most people believe atoms are tiny spheres with tinier spheres rotating around them.
I see it more as the ("positive") holes between the (negative) balls propagating through the wire (in the correction direction, from positive to negative).
Of course the reason that positively and negatively charged particles push and pull on each other in the first place is the existence of the electromagnetic field. Or rather, these forces are described by the electricomagnetic field equations.
There's no such thing as actual explanation of what electrons do. Science builds a model, the model needs to fit experimental results, no definitive link to "the fabric of the universe"
An amazing conversation, and the editing adds a lot of context someone might need to fully understand it. Great video!
Lol 100K views in few hours, Stunning what he created on here, just stunning, If he only talked deeper into the electro magnetic world he would have a cult following, guess he doesn't need that headache Lol
I appreciate that this is simply a humble discussion between you two. And that humbleness is what keeps me coming back Mehdi!
ElectroBOOM just gave us a master class in how to conduct yourself as a scientist as well as a person. He wasn’t afraid to admit when he was wrong, was open to ideas that seemed to contradict his own, but also stuck to his guns and was able to incorporate the new ideas to agree with his already established ones.
It was as you say, a master class interaction and I loved it. As to the topic, I've got degrees in both physics and also EE (semiconductor focus) and in my opinion it is still worthwhile to explore some of the basics in areas such as what they discussed as there are likely flaws in some commonly held views on how things really work. If more scientists would approach a debate such as these two, humanity could progress much faster.
It is expected from a scientist though
Amen,
how real science is done! i grew up with the same notion that electroboom had (and had to suffer the period where our instructors changed to positive hole carriers instead of electron flow or negative flow- i thought that was stupid and constantly battling young engineers that grew up during that period!)
@@reformed_attempt_1neither of them are scientists tho. Neither of them have published any papers. They're science communicators
Derek didn’t contribute much to the thought process, he just read 1 paragraph he saw in a textbook. That’s what he based his video on, and that’s what he read now. No analysis, really. And then he wrote to the author of the book for more info 😂😂 and the author didn’t explain beyond saying that ‘clearly’ they don’t move. Something seems off w veretasiums analysis or lack thereof. Electroboom, in the future I would talk to the primary source for more info, find a scientist, wouldn’t be hard. Otherwise you may find yourself in a loop w Derek greater than the one in the experiment.
very interesting discussion! 👏
looking forward to see your test!
hey man. why tf are you here. I love you channel btw bro. keep it up!
@@shinsoku9128 generic boring reply to a popular youtube channel's comment. why wouldn't he be here?
@@smokejc why would he be here
@@smokejc ? Do you even know his channel? He does 3d printing stuff. So why would he be here watching mehdi?
@@shinsoku9128 you know that people are allowed to be interested in different things, right? I don't understand this idea that someone with a 3D printing channel cannot watch a channel about electronics. Myself, I'm interested in electronics, mathematics, physics, painting, comedy, home improvement, and much more. If you saw my list of subscribed channels, you'd know the different things I like, but certainly one doesn't preclude me from enjoying another.
It's important to distinguish high frequency current from DC current. It's the high frequency field current (coming from the switch action) that flows on the surface of the wire (skin depth phenomenon) and propagates through air on a shortcut to the light bulb. This is why a smaller potential is seen first before the DC field current makes its way around through the bulk of the wire.
This is also why there is a different effective resistance of wires for AC than there is for DC. For DC in the steady state, the current density flows uniformly through the wire, and you can determine the resistance, just from extrapolating material resistivity, using the definition of resistivity to adapt to the conductor size. For AC, there is a concentration of current on the outside due to the skin effect, such that for wires that are about 50 mm^2 [#1/0 AWG] and larger, there is slightly more effective resistance for AC circuits than DC circuits using the same wire.
Late comment, but this thread was itching a scratch that was burning through both their explanations.
It's instructive to look at HVDC lines.
en.m.wikipedia.org/wiki/HVDC_Inter-Island
(Go to the Technical Description section and scroll down for an image of the cable.)
The core has strands but they are thick. DC is much more like the analogy if water flowing in a pipe. You have a high pressure source and a low pressure sink. The net flow will be in average in a specific direction. With relative uniformity relating to the flow of charge through a cross section.
When a strong electric field is applied you have atoms reaching an excited energy state and electrons move to a higher valence position. And become mobile in a stabilized field unchanging electric field.(DC except for the dynamics related to the circuit turning on or off.)
Looking at AC, energy is transferred in a much different way, through the vibration of charge back and forth in a wire. Then nature of the changes in the electric field lead to more electrodynamic qualities.
You can see this in a cross section of a transmission wire for HVAC
en.m.wikipedia.org/wiki/Submarine_power_cable
In the HVDC cable the conductor is the center core and the insulation keeps charge from leaking. There are also steel wires to provide the cable structural strength and protection.
For the 3 phase HVAC you have 3 coaxial setups where there is a core conductor, a uniform dielectric, and an outer conductor.
This design helps contain the more chaotic and dynamic electric field. In fact, the dielectric becomes as important as it affects the capacitance of the transmission line.
In the AC model, the movement of charges is much more chaotic.
This can be explored further but much of the questions about the electric field set up in a conductor by a battery, dynamo, or ac generator can gain insight by looking at the differences in construction of HVAC vs HVDC cables.
This has been one of my favorite RUclips “dramas” to follow. Amazing conversations and perspectives from many parties. I studied conventional and electron theory in college but I feel like I have learned a whole lot more from this “series”. I love it.
This is the only drama I want to see.
I really wish the vast majority of RUclips was this, rather than 99% mind-numbing dreck.
Are you calling conventional electro booms view and Derek’s view the electron theory? Because I’m not sure what you mean by those terms?
@@TriThom50 No, this is outside of both of those theories. Electron theory suggests that energy is transmitted from the negative leads, and conventional suggests that the positive lead carries the energy. There’s a lot more to it than that but that’s the gist of it.
@@ThaScruffShop are you talking about with current in terms of which way the charges are actually flowing? Because that is something different than energy, and this video has nothing to do with that topic.
I assume you are talking about something else, and that was never mentioned in my degree.
The issue with those kinds of questions, is that they are overly simplified. Which always leads to endless discussions. The discussion perfectly shows that as well.
quantum field perspective and understanding is more precise and subtle.
you're replying to a bot
This is always a break point with scientists and engineers as well. Electroboom has done this in the past where he uses more simplified equations because for general use, they work. Scientists want everyone to use diffy q's to find the exact answer. Great but we don't have time for that on a project. We use simplified equations because on macroscale, it works.
@@ganon8835 I was gonna say, i literally just reported the bot and then i read ice bread's response to it as if it is an actual person or it making an actual point.
Then again, i didn't click on the link, as i refuse to click links without proper context as they're _almost_ always some scam or lame unrelated video. (as i found out in the past when it was new).
So idk, either ice bread is a bot as well, or just didn't pay attention and probably also did not click the link, unless the link was actually relevant, then the commenter just did a poor job at communicating it, because saying "finally it is here" is exactly what bots say.
EDIT: well, there's more bots than users at this point...
_ELON?!_
was about to say the same, i totally agree
Enthustic people are no specialists
Heck even specialists have no answer that is 100% right
Just look at the equation, do the math, and thats the end
Math is way nore precise than any words can be
This is tremendously interesting and I love the more in-depth, nuanced electrical discussions. This video was edited very well and kept everything understandable, great visuals.
N,NBnlB,znb,,,☆,¡》a,N,a,NN,n,nN,nnnNNNnnnNnnbNwN,nnnNBb
I could understand more before I saw this video! I think that the explanation with "push and pull" and the one with electric field are equal, because they are just different theories representing the same phenomana. But, I think using electric field to understand this is better, because field can represent the situation more correctly where all the electrons contribute to the field and are affected by it, which mean this explanation include all the objects, electrons, protons and a battery, whereas "push and pull" theory only consider close particles as approximation. But, still they are the same!
Look Up Rick Hartley (PCB Design)
Look Up Rick Astley (Never Gonna Give You Up)
I have been following this discussion for a while now and it's nice to see the both of you reaching a unified outcome. It's all about education! My Grandfather use to always say, "If you don't learn something new everyday then it's not worth living."
Cool grandfather. If you ask me that's how you keep your brain working; by using it. Plenty of research supports this, and as such, I'm fairly confident that it is basically true. my own observations would be consistent with this as well. obviously thinking all by itself, isn't going to cure some major neuro-degenerative condition, but we know what we're talking about
Peace be upon you, sir.
I always thought of electric current as free electrons being pulled in sync by the next electron's increasingly +ve nucleus as its electron moves away, to be replaced by the incoming electron. Not completely in sync due to the electrical imbalance signal travelling at a fixed upper limit (C, speed of light).
--
Batteries work due to the imbalanced nature of many chemicals, some relatively positive, some negative. Separate +ve and -ve chemical using some insulating boundary in a battery and connect a conductor from +ve to -ve. Each -ve electron is PULLED to the positive side, with each subsequent electron playing follow my leader.
--
Vibrations between close-packed (semi) free electrons travel at C.
the unified outcome being... more views.
The editing was superb and the conversation was great showing the way you guys bounced ideas off each other
Where the field point of view DOES matter in EE design is when looking at PCB design, particularly where the return current flows in a circuit trace over a GND plane below (particularly for higher frequencies). The current associated with a changing signal (e.g. a pulse through the trace) in the GND plane is actually right below the trace, as it is caused by the changing field by the trace. So even if the trace meanders and zigzags all over the PCB, the return current to close the circuit through the GND plane does not choose the shortest path between the contact points, but also follows a meandering zigzagging path as dictated by the field, which follows the path of the circuit trace. Further, if you imagine sending a pulse through a trace, through a load, and then back through the GND plane, the pulse does not travel in a circle out to the load and then back through GND, like a marble on a marble track, or like water through a hose.
Rather, as the pulse starts traveling along the trace, AT THE SAME TIME an opposite return current starts forming underneath the trace, traveling in unison with the signal, until it reaches the load. This is exactly like the Veritasium thought experiment - current right under the trace in the GND plane starts flowing right underneath the trace, in parallel with the changing signal. Robert Feranec has a few very good videos on the topic. ruclips.net/video/4nEd1jTTIUQ/видео.html
For me at least, this was really a mental switch where it "clicked" - the intuitive idea of "electrons pushing through wires", or even, kinda like water going through pipes, didn't make sense to explain what's actually going on, but thinking in terms of fields, and where those fields are, does really help to understand. This is hugely important when designing HF or RF PCBs, and for EMI compliance (and yes, even an 8Mhz ATMega is high frequency, as the clock edges change within nanoseconds, i.e. 100s of Mhz with harmonics in GHz range).
lost me; fact is, perhaps that ain't hard to do. It sounded like you knew what you were talking about though... and for some reason, I'm going to read what you said about 10 times. Good job.
peace.
upvote this so mehdi sees y'all
So would then a "newton's cradle" model work for the energy transfer? At the speed of electrons through a material, the newton's cradle pieces interact and the interaction between the fields carries the energy in reality. Then after "hitting" one side of the newton's cradle it would slowly push the whole assembly to the direction of energy transfer and kind of explain electron drift?
Although the water analogies are quite common, a much better way of looking at the electrical phenomena would be bicycle chain analogies.
The water model can still be used as a description. One must only not make the mistake of taking an empty pipe for the description.
The parallel propagation of the electric fields can be described in so far that each pipe is basically filled with water. As soon as water is added to the outward pipe, the same amount of water flows back on the return pipe.
Amazing discussion. I loved the way you both compliment each other. I’m learning both electricity and how to respect each other. Kudos
We need more of these kinds of collabs between science communicators on RUclips! Seeing these sort of back and forth not only allow me to better understand whats going on but also contribute to the scientific community and encourage public discussion of topics that otherwise would go over my head
You understood something I was just watching... Idk what they were even talking about
The analogy I use is each electron is a man with a bucket in a bucket brigade and the water is the electrons . when not connected to a battery the buckets are full of water. when connected to the battery the chemical energy strips electrons from the + conductor or in the analogy empies its bucket into tbe electorlyte of the battery . the man with a full bucket next to the man with an empty one ,dumps his bucket into
the empty one making his bucket empty and the next guy dumps his and so on. this in effect causes an empty bucket to move from + to - .
Yeah I think that this kind of high-quality back-and-forth is exactly the niche that science RUclips channels can fill in sci-comm.
It's very much a Socratic dialogue for all of us watching. Brilliant stuff
This discussion works as an example of how to discuss about everything in life.
Regardless of your views on the nature of electricity and charge gradient in conductors,
*this is a tremendously important video* because it shows two intelligent adults having a civic, relevant and pertinent discussion.
Very nice collab 👍
And they still good friends at the end?
I do like having a Honda Civic First Gen (1972) discussion with other adults
@@goober13579 Especially when it involves civic centre bearings.
I think you mean civil
Tremendeous
About gradient having opposite effects according to each of you, I just want to point out that in electric guitar magnetic pickups, the amount of wire around the poles DOES have two conflicting effects. It results in inductance but also impedance, which means that depending on the impedance of the receiving circuit the perceived output may be higher or lower. You'll find nonsensical results such as "mixing two pickups of radically different sizes will result in the quiet one dominating the loud one" (seen in the Gibson EB3 for example)
Gibson guitars r pretty sweet
About the surface charges inducing a current in the conductor but also drifting along the surface of the conductor.
If the surface charges do drift the reason why they might have a negligible effect on the current in the conductor is because of their volumetric state. If you add up all the available electron charges on the surface they will be vastly outnumbered by the available electron charges in the bulk of the conductor. So even if they do drift along the surface of the conductor their charge effect on the conductor remains the same but their energy contribution to the load is negligible.
This is why for some types of circuit impedance matching and transmission line theory are so important.
@ElectroBOOM. There is also another information you could add to your analysis. About electrons being able to push something, you may investigate the electromigration phenomena, where electrons transfer momentum to the ions present in very thin conductors (again, as you said, it depends on what do you call push).
Just like with the Steve Mould's video your reactions are perfect for me. They are not here to prove the original wrong, rather to explain a few concepts better. I usually have similar questions as you do and you research them for me, thanks!
Thank you Mehdi. I found this video extremely helpful. After studying EE for 3 years i find it baffeling, frustrating and also fascinating that the "simplest" concepts are very much not as simple as they seem
Excellent arguments! I agree with you 100%. I can’t think of a reason the surface charges should be in bound states, and calling their current “negligible” doesn’t really help, because if that same quantity of charge were distributed (radially) through the wire as your (and my) initial mental model stated, the total axial current doesn’t change at all.
Since talking to Derek about this I’ve been trying to think of any reason they could be bound, and beyond the surface charges that are intrinsic to the material interface/workfunction/whatever that should always exist and be uniform throughout the material, there’s no reason the mobile electrons can’t push on each other.
The only bit I would add is that “batteries” don’t supply an electric field, they just pump electrons around in the most direct way possible, but with the thenevin and norton and whatnot we know it doesn’t matter 😁
I’m in the process of trying to set up a water model of exactly what you drew here on the whiteboard to demonstrate ohms law so I think we couldn’t be in closer agreement lol.
Now I need to go watch your long wire experiment - I heard from a friend of mine that’s already watched you were able to get it properly impedance matched where Derek and I both missed the mark, so I’m looking forward to it!
When are u going to show us a follow up video of what happens at your other resistor, ie that made your brain melt?
My new (electon) electricity says that electricity aint due to drifting electrons, it is due to photons (electons) hugging the surface of the Cu.
The electons propagate in the insulation (if any) in which case they propagate at the speed of light in the plastic, about 2c/3.
On bare wires the speed of electricity is 1c.
A good conductor is a substance that a photon can hug, eg all metals are goodish conductors i think.
The hugging is strong if there are free-ish conduction electrons in the wire -- Cu has 2 such electrons per atom.
Electons don’t reflect, they do a U-turn at the end of the wire.
Actually, electons always go straight ahead, it is the surface of the Cu that duz the U-turn.
If Mehdi measures the speed of electricity along a threaded rod he will find that the time taken is longer than for a plain rod, the difference being exactly the extra distance up & down over the threads.
Mehdi or u should do a youtube about this.
Your welcome.
@alphaphoenix compare two multi strand conductors of the same total areas made up of different strand counts.
Is the current carrying capacity of the higher strand count greater and with better efficiency specifically because of the surface charge effect?
Good luck with your water experiments!
Will the water model show how the insulation on a wire slows the electricity to 2c/3?
Praps AlphaPhoenix can put insulation or something on the outside of the pipe -- hmmmmm -- nah, that wont do anything.
Anyhow neither Derek nor Brian nor Dave nor Mehdi nor Bob nor Nick have in their youtubes explained how insulation on a wire slows electricity.
Derek did have a try -- he said that the insulation slowed the speed of the Poynting Field/Vector -- which then raises the question -- how does 1 mm of plastic slow the Poynting by 1c/3, when say over 99% of the Poynting is outside the plastic?
The 1 mm of plastic will have little affect on the 1/c time delay for the speed of the induction across the 1m gap (talking about Derek's original gedanken here) -- it will add say 3/1000c sec to the time for the bulb to light -- koz the speed of the em radiation will spend 1 mm plus 1 mm = 2 mm in plastic on the 2 wires, which adds 0.003/c seconds to Derek's 1/c seconds.
But, while all of that is happening across the 1000 mm gap (in the original gedanken), the speed of the electricity around the long circuit is 2c/3 (assuming that the full length of wire is insulated) (Derek didnt say).
Actually, Derek did say, he said that the half circuit was 300,000 km long, & that the electricity would take 1 sec, which implies zero insulation.
But, we can see that all of the wire shown in his video is insulated, the wire to & from the battery, & the wire to & from the light-bulb.
And, Derek keeps saying that the distance to the light-bulb is 1 m -- distance from what? -- from the other wire? -- from the battery? -- from the switch?
Derek should have said from the switch. But he didnt. Koz he duznt know how electricity & induction works. Sheeeesh!
And, like i said, Derek doesnt know that insulation slows electricity to 2c/3. Double sheeeeesh!
Loved the colab! Way better than video/response. Good work, guys!
Finally!! Great stuff! I've been teaching the "spitting/sucking electrons" model for batteries for ages, seems obvious once you've built a Daniell battery once in your life. Recharge it and look at that Zinc build up and Copper ions in the solution. The fact that the battery delivers energy through the + AND the - becomes apparent.
But what about AC...
"Commendation from NASA for research work at Massachusetts Institute of Technology on the Earth's atmosphere and the Moon's surface for navigation of the Apollo spacecraft to the Moon..
Dr. Milo Wolff has found the structure of the electron consisting of two spherical quantum waves, one moving radially outward and another moving radially inward. The center of the waves is the nominal location of the electron 'particle'. These waves extend infinitely, like charge force. All 'particle' waves mix and contribute to each other, thus all matter of the universe is interrelated by this intimate connection between the fundamental 'particles' and the universe. The natural laws are a direct consequence of this Wave Structure of Matter (WSM), thus WSM underlies all of science."
spaceandmotion
@@Breakfast_of_Champions same thing, just the direction of sucking/spitting gets inverted a few times per second. And actually the wave effect Mehdi talks about allows to explain capacitive and inductive effects in that case.
What about thunder foot disproving your video about water
a battery doesn't deliver energy from both poles
1) What Veritasium (and ElectroBOOM) is missing is that you simply cannot separate charge from field distribution. If you look at Maxwell equations there is not way to separate one from the other. The charges move because of the field, while charges are creating the field. You can't make arguments for both, and both can give you a usable explanation within certain frames of reference, but neither charges nor fields can be considered independently.
2) Technically nothing pushes anything else by touch since the only mediators of force are the fundamentals forces of nature, and since the only one that applies at lengths larger than the nucleus of an atom is the electromagnetic force (gravity too but not of interested here), EVERYTHING is moved away by the actions of the fields link to that matter. For example: If someone slaps you in the face, it will still be the electromagnetic fields in the atoms on your friend's hand that exchange energy with your face.
3) Veritasiums problem was a trick question not because it was not correct, but because our common (and the only one with a meaningful use) understanding of when a lamp bulb is on is at the steady state. If the lamp is on or off is not a matter of physics, but a matter of agreement, and commonly we agree that the lamp is on when it is FULLY ON, when the electrons go around the whole loop. This is why the this is a trick question, because he challenges common expectations and abuses the definition of what makes a lamp being on.
I love the way you do this, like with Steve Mould's chain fountain. Two people trying to prove each other wrong in a civil manner is both fun and a great way to learn!
Also a great reminder that everything in science is just models to simplify and understand complex things
Except masks and vaccines. Those are undeniable unquestionable doctrine. The science has spoken, bow and obey.
@@supremelordoftheuniverse5449 ???
...and also another great reminder of how things could be if everybody was... well I don't know... what would one call it...? civil? normal? like adults with concerns and priorities that are exactly what they state them to be? Instead of the stuff you tend to find out there, randomly. I don't want to say anything bad about anybody... but most people suck. Not these people, however.
Peace be upon you, sir.
Derek`s explanation of currents flowing over wires much reminds me of how currents flow through our bodies: by subtle disturbances of the charges around a membrane. It`s as if in our bodies the inside of the wires, being electrically neutral, serve other cellular functions, thus making for much better use of space and allowing for "intelligent wires" which change their properties based on how cell membrane and other changes induce changes in the ambient surrounding the membrane and the membrane properties.
Except nerve conduction is done by the flow of ions through channels. Not by some field with unmoving particles like Derek claims.
I did some of this in College and I’m glad it’s not so straightforward to you guys either, I came away with the impression that mental models are for accurately modelling outcomes for engineering and the truth is for philosophers to debate.
Yep.
I’d say the truth is more for scientists who create experiments and run simulations that test the different mental models (so for example, a transient analysis of current flow in parallel resistors that could validate or invalidate Mehdi’s hypothesis earlier that current self-corrects via bulk electron interactions and not just EM field propagation) to decide, but yes, I’m glad there’s this acknowledgement that these things aren’t so straightforward
Not for philosophers but quantum physics professional. This is typically a particule physics problem.
good summary
I've always loved watching your videos. Growing up in a poor community was extremely difficult, and my lack of self-discipline did not help my decision making. From being a gettho child who had no high school education doomed to fail, to now finishing my higher education in computer science. I want to become a cyber security specialist. I just want you to know, you're part of my inspiration.
Congratulations ❤
congrats! that's awesome bro!
Admirable! Keep it up, bro!
Same here bro. Congrats!
What I love is that they are pointing out that the accepted model (while it works very well) does present a lot of common questions which are NOT stupid and actually quite logical.
Classical models really aren't geared to give insight on the behavior of individual elections. They work well enough for nearly all practical applications, but eventually they break down and you need quantum models to get any additional insight.
@@theviolator23 Thank you! finally someone that goes to the core of the issue. They keep trying to use classical models, i.e. Drude's model, to treat an inherently high frequency problem that is outside of the scope of validity of their question, and then wonder why the results don't match with expectations.
The "misconceptions" are not misconceptions, simply different models which are valid in some cases only because they use assumptions that reduce their validity to specific situations. Is like using classical mechanics to solve a special relativity problem.
@@theviolator23 My point was more that such models are usually taught without any hint as to their limitations. Personally, I find knowing such things helps me accept such models because it tells me my gut feelings are right.
@@stevenspmd Exactly. If you're taught that the model is just that, an approximation, and has limitations, then it's much easier to suppress that knowledge later on when you come across a problem that requires it. Otherwise you effectively need to "un-learn" it and it's really difficult
this was the most scientific way to comment a video: an specialist arguing (his believe) with another specialist backing up his theory with citations! just amazing
This is the internet at its best! Two minds comparing notes, both trying to improve their understanding of how the universe works, no egos getting in the way. Thank you for sharing this discussion!
You guys should really include nick from “the science asylum” in this. He made a really well animated and explained video discussing all this pretty much, about 2 years ago.
He’s criminally under-subbed.
Veritasium referred to him in one of the videos.
Do you have the link?
AlphaPheonix did the actual experiment with 1km wire. See what actually happen rather than only see theoretical discussion.
@@santiagocabascango6514 ruclips.net/video/C7tQJ42nGno/видео.html
@@xponen Derek mentioned him on his last video on the topic and recreated his test with the same results.
Physics grad here. One of the engineering physics questions that totally made students insane was to calculate the average drift velocity for electrons in a wire and calculating the eclectic field in a wire.
Those questions were always MORE difficult for students that understood Kerkoffs loop laws and could model circuits well. Turn on a light and let it run for a bit turn it off. The average electron has moved and incomprehensibly short amount. Blows peoples minds. I was a tutor and every year every Professor would assign the problem. Students who rarely, if ever, came for help would come for help on the problem they "got wrong" they all thought they had an order of magnitude problem or problem with vector field modeling.
I am not surprised that people are confused with this and ALSO get the idea that it does not matter much. We teach circuits in a way that helps people understand and use them correctly. Probably using a working modle is what's MOST important.
You sir remain true to your name
@@filips7158 it is dyslexia, don't be so harsh
@@Vintik_51 I know, nothing mean or bad implied
Awesome discussion - reading up on skin-effect in AC Transmission lines - the traditional model is quite effective in explaining so many of the practical questions around electricity…
This has been so informative. Thanks for your insight and helping us understand these more complex things. You're awesome and I love your videos
I have a EET background, and I thought of the current of electrons in a way similar to you. A surplus of electrons in the wire close to the negative terminal pushes electrons ahead to fill holes in the wire close to the positive terminal. The longer the wire, the higher the resistance because you are needing to overcome a static resistance. If the conduit has a larger cross sectional area, i.e. a higher guage, then it lowers the resistance because some of those electrons in the matrix have the ability to move out of the way. The immediate way most people would understand what I'm saying is that the wire is like a pipe, but it is more like an inverted pipe. The electrons are moving on the surface, but the same properties hold true in that the higher guage has less resistance and that the differential gives electrons a way to overcome that internal resistance and push other electrons forward...
But superconductors change that perspective for me. A superconductor wouldn't have a gradient. You can't use a DMM and measure a voltage potential across a superconductor and yet it will still carry a current. This would suggest that since the electrons are free to move through the matrix there must be some other force moving them. If it isn't the force of a gradient applied across the conductor, then the only other obvious force would be the field. If a field applies to a superconductor, then it stands to reason that the field would apply to any conductor.
I think that the classical way of modeling electricity like water pushing through a pipe is still a good way to think about what is happening in a circuit for most circuits someone would build on a bench with a breadboard or a soldering iron, however it doesn't capture the reality of why and what is truly happening in a circuit.
Amazing comment, thanks.
Superconductors dont have a gradient, but they also do not require a field. All they need is an initial electron movement, and it will continue to persist.
Whatever the case with superconductors, the fields couldn't be outside it, because then it would result in energy leaks, but we know a superconductor is lossless. So whatever is happening, it has to happen INSIDE the superconductor, yes? So then how can it be wrong to say it's simply a matter of electron interactions within the superconductor?
@@greg77389 I'm not sure that's completely true. I remember bringing this up once in a physics class, with a superconductor with an induced current and an ideal pair of inductor and capacitor. The claim was that the current would continue to flow in oscillation unless there was some external force. To verify it, you could sense the field and reintroduce another field to restore whatever was removed by the sensing... This thought experiment has hypothetical ideal components, but it didn't seem to sway my instructor that you couldn't introduce a current external to the superconductor. Furthermore, I believe it is this property about the fields extending outside the superconductor that allows for the locking you see when suspending a magnet over the superconductor.
But electrons can't move - that is, current can't flow - without a charge gradient. Charge gradients *are* the active component of the electric field.
An interesting addition to the experiment: a third wire in between, in parallel to 2 wires, with a load in the middle. Ends not connected to anything. I expect it to act in the same way like the original load would, but current will die out as soon as the wave travels all the way.
Effectively it would show that the initial low current in the load is propagated as a basically radio wave, until the wave propagates through the whole wire and creates a closed loop.
While the initial wave spreads, it creates an effectively a changing electric fields, and changing electric fields, quoting Faraday, induce currents.
In my opinion you are getting some of it. Every electric current is generating a radio wave I believe. In reality a DC current is also an AC current just with a very low frequency. A square wave (what switching on a DC current is) is generated by an infinity of odd harmonics (as far as I remember) and there fore the initial switching on generates very high frequencies. These very high frequencies will of cause transfer energy to anything they get to and they are moving with the speed of light. It is these high frequency harmonics that gives the initial energy to the lamp I believe - but it is the main current that comes along the wire some how that transfers the main energy to the lamp. The radio pulses are actually losses as they go every where.
This description does not originate with veritasium, it is now well over 30 years old, although I am not aware when it was first introduced. The text book referenced is Matter and Interactions by Bruce Sherwood and Ruth Chabay. Despite also being an EE, I was not exposed to theses concepts/ideas until I read the 1999 paper "A unified treatment of electrostatics and circuits" by the same authors some 15 years ago. So while this is nothing new, is SEEMS new since it is simply not taught and rarely discussed.
A ton of learning from this one. So my takeaway is: electrons probably drift slowly because they end up having a positive net force forward in a charge gradient that is caused when voltage is applied, but they don't carry significant energy, fields do. Fields propagate, electrons follow and generate the fields or something, fields do the work. There's still something to be clarified about electrons generating fields and how the fields carry energy, as well as how resistance is properly visualized as fields. Awesome you're clarifying this!
These collaborations are great. Especially in the form of discussion where it's back and forth exchange of ideas and answers and explanations, which takes a lot of gaps out immediately - the follow up questions get answered or discussed right away. The ones that might be hidden from the one making an explanatory video, but a mystery to the one watching it. Great video.
I especially like the close-up of his grey carpet as the background when the guys are chatting. Lovely. Grey carpet is very popular 👍
This was such an epic back and forth I learned more from both of you than I could have learned from just one or the other
16:11 i think a helpful analogy for the surfaces charges applying the force that moves all of electrons is one of those “bladeless” fans. those fans work with a fan in its base speeding up air. this moving air is then ducted into a ring. due to the viscous affects, the air that originated from the base fan imparts its energy to the static air inside the ring. this means that a small amount of faster moving air from the ring results in all the air moving at a slower rate. the most of the air is static until viscous forces move it. this is like the charges inside the wire. they do not have net movement on their own but with the surfaces charges they do move. and based on the book these inner charges make up a majority of the current. just like in the fan the originally static air has more mass than the fast air from fan in the base. also the air from the fan does also move like the surfaces charges
That's a great analogy! (TLDR at the end)
Towards the end of the video, and before reading your comment I was thinking of the water pipe pressure/flow (voltage/current) analogy and came up with a simple modifier to it:
-Imagine the same water pipe pressure/flow idea, but consider that the pipe is 1m (3ft) in diameter and the pipe inlet/outlets to battery/load are only 1cm (3/8"). This would explain how without 'pressure' there's no voltage, and that 'water' (electrons) coming into the pipe, nothing can leave, but they will move at a VERY SLOW rate. As AlphaPhoenix measured here: ruclips.net/video/rQIg5XeIgQ0/видео.htmlsi=sECQJgL35hNRfMf5&t=162 only 1 part per quadrillion of the wire's electrons are being moved to charge 28m of wire to 1.5V, and putting the two pieces of info together it seems that, indeed, "electrons MUST push each other to carry a current" while also seemingly NOT MOVING, but that's just because there are sooooooooo many more electrons in the wire that their movement is negligible.
TLDR; Neither idea is wrong because there are soooooooo many electrons in the wires, so that that only about 0.0000000001% of them need to enter/leave the wire in order for current to flow. So yes, electrons push each other, but there are so many that they overall move veeeery slowly.
This has blown my mindhole. The explanation of how the surface charge gradient pushes electrons in a specific direction somwhow lead me to understand why sparks usually occur at sharp points. The gradient diagram for a wire with sharp end looks so amazing. Gave me an entirely new perspective.
in a wire there is no surface charge or such things electrons dose not distinguishes between surface and non surface space. it is the radiation of electrons in a magneticfield of an Atom causes and that is why it depends on the resistive of surrounding or interconnected object.
Mindhole... Wtf ?
Very interesting discussion. I would really like to see this discussion extended to include skin effect and eddy currents as the mechanism behind that. Like you mentioned: a transient DC current wave must propagate through the wire to get to an equilibrium, and I would expect that the initial skin depth is very shallow and while getting to the equilibrium, the depth increases, to finally make electrons move in the whole wire.
I was waiting for them to touch on the skin effect the entire time!
This actually explains not only why the skin effect exists, but also why it is more pronounced on higher frequencies!
These discussions end up being muvh more exciting than the original videos! Thanks for sharing them.
When I first started learning about electronics I thought charges pushed each other, but after a while it didn't made sense to me, because how would it know what path to go beforehand? So then I started to imagine charges were "sucked" from the negative side to the positive side, so the positive charges were attacting pulling the charges, while they would be pushing each other as well, and the pull from the protons would guide them.... But after reading about singnal integrity and electromagnetic compatibility, I know it was all wrong lol
Just wait until the quantum magic wreckers that mental model.
How did the particle know there were two holes instead of one?
There is no connected battery or anything. But if you shoot particles, one at a time, through two holes (slits) instead of one, they behave differently.
What the fuck
@@astronemir 😩🤯
No that's bullshit. The particle doesn't need to know anything. No changes between wave and particle forms. No zombie cats. Just a particle riding a wave and hidden variables. Look up the pilote wave theory. It makes so much senses that physicist dislike it. Stories about zombie cats and multiverses sell better than particles riding on waves. That's why Harry Potter makes more cash than Electro Boom.
The back and forth on this topic makes me think of the difference between Newtonian and Einsteinian mechanics. Newtonian mechanics continue to serve us well in our daily lives, until the deeper reality has a non-negligible impact on a system.
I'm very excited to see your replication of this experiment. I wonder how you will lower the noise floor of your measurements. If you're able to approach the ideal configuration, as described in your previous video, it would be amazing to see that in your measurement.
Or how quantum mechanics are generally able to be ignored, because at a macro scale they don't really do much, but in some cases they become super important, like if we build transistors in CPUs much smaller electrons will start quantum tunnelling
@@__8120 As someone put it, we're already using numbers like the Coupling Constant without even understanding where it comes from or why it works.
As soon as we started getting past "FIRE. HOT." the answers kept leading to more questions and the questions kept getting harder to answer.
At the end of the day, it's just math, and we're here just nitpicking over the best words and models to use to explain it.
The deeper we go, our normal language starts to break down, and does an increasingly poor job of translating the math to English/whatever
For the record though, I'm more inclined towards Veratasium's viewpoint
That's exactly what I thought.
I literally went through the comments to see if someone said this. If not I owuld have said it myself. Models serve us by simplifying the phenomenon in order for us to make use of it. Since the point is using it, as long as it works, let's use. While the more accurate description of the situation helps us wit hdiscovery and improving our technology. telling the difference between both views is like comparing researchers and engineers : Each serve a different thing but they are both aware of each others workwhile being 100% essential.
Amazing video. Now let's see how in AC, the high frequency current moves around the wires. I guess it'd be very similar to this, but with all the spice of skin effect, and the rapid polarity change.
I just commented this, that's why in a HF application, core size is important. HF requires very fine multi core so that surface charge can propagate quickly
@@mrpdude84 @hosemarino Now you both please explain how the "around the wire"/skin effect in HF applies in the case of a Bipolar Junction Transistor. E.g. the good old 2n2222 works up to 300MHz
This entire problem is one of AC. Whenever a direct current starts or stops, you get the same effect as AC.
The DC only kicks in when the wave of electrons travels all the way from power to load. And I believe it was around 5x higher than the phantom power you get at the 1/c time.
So Veritasium is right for maybe 20% of the power. ElectroBOOM is right about the electrons pushing for the other 80%.
Your second big explanation just literally recaps that the mobile electrons are still only moved by the outside charge, not by each other. Let alone no one ever argued originally the electrons didn't flow at all.
I CAN COUNT ELECTRONS! .
Hi EBOOM & Veritasium , I work with SEMs (Scanning Electron Microscope) and I must insist that the electrons do move from the negative to the positive of the power supply actually "move" pushing each other and really moving .
If this was not the case we would not get the ability to control them in vacuum using EM/ES fields or have them interact with the material they are "bombarding" .
We can even measure each electrons energy and count them (almost one by one)
But the coupling between them is purely the static field.
if that is the case, then electrons and holes wouldn't move to form depletion layer .
But why do they move? Why do electrically charged particles act on each other? We explain this with the electromagnetic field.
@@ronald3836well if they didn’t move, how come that a normal light bulb does heat up and produce light? Or how does an oscilloscope produce free electrons that literally flow onto a screen?
In addition you can measure the heat that is produced by the friction of the moving electrons insight a wire.
@@eintennisspieler4259 I'm not saying they don't move (they do, but rather slowly). I'm saying it is the field that makes them move, not the electrons moving that makes the field.
However part of this is just the mathematical model we use to explain the physical phenomenon of electricity. In this model, it is the field that makes the electrons move. And the model seems pretty accurate.
11:00 I remember asking this exact question in my middle/high school physics class. I also remember making a pretty big deal about it in my back and forth with the teacher, so this whole discussion is very interesting to me.
From my engineering courses, especially the ones relating to maxwell's equations, for DC the cross section of wires have uniform electric fields in terms of density. Unlike AC where the electrons concentrate in a skin surface around the conductor and therefore the electric fields aren't uniform within the crossectional area but along the perimeter.
Yea! Came here to see if anyone else is thinking this - neither* of them are taking them/frequency into account in their analysis.
Btw in skin effect the electrons don’t concentrate - the current does (mobile electrons)
*Mehdi did briefly
@@lawrencejob current as in the motion of free electrons, coulombs per second. They diverge because of similar charges standing still. The AC VS DC. Current or electrons, whatever is there to move. Right?
@@xDR1TeK For sure, what I was trying to say was that as far as I know, the actual electron concentration doesn’t change based on frequency so much as the ones at the “skin” are able to be much more mobile (and therefore current) because they’re not “impeded” by the eddys inside the conductor.
Although I’m doubting myself now 😅
Such an interesting conversation, thank you!
@@lawrencejob I thank you for your patience and understanding. I'm not perfect.
@@xDR1TeK How then does conductor material change surface charge capacity? Why does the surface of an aluminum conductor have a smaller surface charge than a gold or platinum conductor if the surface area remains constant? Does this mean that the conductor material matters even though the charge travels across the surface only?
Respected sir @13.51 isn't the direction of gathering of electrons more towards positive terminal of the battery.
I saw a video from a physicist AlphaPhoenix putting this to the test with 1km of wire and an oscilloscope. It showed there was an immediate movement in the wire which then grew quite significantly. If I recall about 20% of the voltage measured conformed to Veritasium's explanation whilst the rest came through at the time you'd anticipate for the more conventional description. That seems a soft confirmation of the traditional theory, but seems to be exactly what one would expect with your later explanation in this video. I wasn't convinced by Veritasium's video but your explanation makes a ton of sense to me and conforms perfectly to the evidence demonstrated. There definitely is a time component one would expect from something travelling along the wire.
The book seems a little odd to me. It describes conductors as just a binary thing rather than a spectrum. Whilst it might not matter to the description being presented it gave a lot of confusion and really wasn't too convincing for that reason. Your description gave a far better and more convincing argument. Veritasium's firm statement of "the light turns on instantly" being (mostly) wrong didn't help my understanding either I would say, even if it was trying to highlight the distinct differences in theory.
Definitely glad I watched this, seeing the debate was very productive towards my understanding. Plus you're amazing at breaking down topics in an understandable way. Very glad for these debates.
I hope he sees this
I think the real problem with the whole debacle is Derek was trying to be clever instead of making the point in a more succinct way. I know he makes money from clicks but that shouldn't make clarity second.
I think the book refers only to the steady state, DC power. We're in the initial state of DC power, which is closer to AC power. We're dealing with changes in current, which means unequal charge distribution.
And without seeing the test I know that both ends of the 1KM of wire where very close to each other. Tell him to try it with the wire stretched out and the scope on one end and the battery at the other end. Creating electromagnetic fields in wire is almost impossible to avoid, they will propagate over and be picked up by any wire nearby.
Yea.. i saw that to.. And as an electrical engineer, the result of the test was exactly what i expected. its not really that strange. We see it all the time in circuit board with high frequency interaction. That is why we have groundplanes everywhere and link them together like every mm.
Great discussion. A bit lost in all this though is you keep showing a DC circuit in your animations and Derek did the same in his original example. But he refers to fields which have more effect in AC circuits. Such as his statement about power line transformers in his original video, that they don’t transfer electrons because it’s not a continuous wire. But a pure DC circuit won’t continuously transfer energy in a transformer circuit, only AC (ignoring pulsed DC circuits). So it’s really a bit of apples and oranges and why they are different but related science (Edison DC vs Tesla AC).
+1.. distribution charges close to surface looks like as well known skin effect that take place in AC .. DC doesn't have skin effect .. isn't it?..
They are talking about dc circuit thou. Electric fields cause current, ac or dc. It's just with ac the electric field switches back and forth.
Also i think you might be using "pure DC circuit" to mean "steady state DC". When a dc power source is first attached, I think we get a voltage impulse which basically behaves like ac.
@@matsaks Skin effect for ac is talking about current density, as in on average electrons on nearer the surface move faster than those in the center. I think they are talking about a similar "skin effect" for charge density here?
Does Veritasium guy have any science background education?
@@PuerRidcully yes, he is a physicist
My biggest problem with what Derek calls "long range" interactions is that it's EM radiation that we call radio. In his second video, one of his sim "proofs" was that a free standing parallel wire carries the same initial weak charge as the loop, but there are two problems with that: first, it's analogous to the reflector elements in a Yagi antenna, which do virtually no work and aren't "read" by a receiver; second, while it mirrors what's happening on the far connected wire, the disconnected wire will not carry the same current as in the circuit because it is disconnected. If we were to watch that sim to an equilibrium-ish state, the (much smaller) radiation field coming off the disconnected wire would affect the circuit until it would reach its own neutral state or the circuits current would be strong enough in relation to the radiation that it would swallow that electronic swashing.
Don't like Derek at all. He tries to make a physical comparison that can't be made., Not just this video/subject.
@@josephlarrybradley508 I come at this whole conversation as someone who holds the highest level of HAM radio license, not as an electrical engineer or physicist, but yeah, his two main points are "surface charge" and "fields." Surface charges are a core component in physical and radio networking because thicker gauge wire correlates really weirdly with signal clarity, so that's not news to anyone that works with cables. In that sense, he's got a point that the wire is not a tube that pushes electrons. However, when he moves from the micro to macro scale, he's making some really weird leaps of logic. Radio waves might jump a gap, but they're probably not going to turn on a light considering the amount of power NFC sensors require. As an aside, he also implied that wireless charging is sending electricity through an imaginary wire, not a manipulation of fields that burns electricity on one end to generate some on the other. Further, the isolated wire that I have the biggest problem with could easily be made into a transformer (another known mechanism) if he closed a loop on it.
@@tyhodnett3031 , indeed, the "long range" / EM wave transfer of energy only works for AC signals. AlphaPhoenix touched on how the initial behaviour is identical to that of a transceiver/transformer setup in his video response to the original Veritasium video.
@@JivanPal I'll watch that one soon. The second Veritasium video referenced it, but Derek's experiment in the second that showed an activity bump glazed over the relative magnitude of the current so I didn't watch any other experiments.
re: "first, it's analogous to the reflector elements in a Yagi antenna, which do virtually no work and aren't "read" by a receiver;"
One has to be careful with this; there are constructive and destructive fields set up by the directors and the so-called 'reflector' as excited by the driven element, and these summed 'fields' create the radiation pattern. Point being, the reflector might be misnamed for this application, but, that's still what we call it.
This feels a little like the confusion that arises when observing waves in the ocean or atmosphere - it’s tempting to see the wave as a feature that moves and influences the flow as it does so, but in actuality the flow moves through the features, not the other way around.
It was really a great polite discussion. I get some additional ideas about the electrons flowing in a wire and i really want to acknowledge both of you.
I was involved in an experiment years ago regarding the speed of electrons in materials (metals). It does vary both by metal and by where you are in the metal (electrons on the surface move faster). That said faster in this particular context is a blistering 0.3mm per second (slower in iron and some other metals). If I remember correctly on the surface of silver, electron speed got all the way up to 0.31mm per second.
That's the drift velocity. Individual electrons zip around at Fermi velocity, which is much much higher.
Actually, in semiconductor physics we see that electrons do ‘push each other’. If there is a carrier gradient, current is created even in the absence of an electric field (as shown by the drift-diffusion equations). Is there any significant diffusion current or any at all in a normal conductor, I wouldn’t know.
Would be interesting to solve (numerically though lol) the drift-diffusion equations coupled with Poisson’s equation and Gauss’s law, on a 3D conductor with a potential difference between the ends. Then we’d have an idea of the actual distribution of fields and surface charges and so on.
I think that in the case of a conductor, all the current inside is drift current, while a part of the (negligible) surface current has to be diffusion current, but that’s just a guess.
"Is there any significant diffusion current or any at all in a normal conductor, I wouldn’t know."
There is, in both directions, in equal proportions. Meaning the net value of the diffusion current is zero. This applies to almost any scenario where there is no current on almost any material. Local currents always exist in lieu of electrons never staying put specially when they are 'free' electrons. But the overall distribution, because of its uniform probability of direction, cancels out to zero.
I can't quote you right now (because its very specific a topic) how the currents in a wire under a potential difference between the ends are distributed (in terms of which is diffusion and drift, etc) but the answer is well known in the field and exhaustive text books on electromagnetic waves and Semi conductors usually contain this information. If I get the time to find my copy of it and review that section I'll gladly return to this comment with the textbook answer.
But when it comes to vacuum tube theory where electrons actually flow, it all goes out the window.
my haunch is that a different behaviour will be observed depending on the cross area of the conductor and the actual number of electrons. I think things change once you can count electrons (in the sense that "the system" behaves differently when you have a small number of electrons)
@@lucianocastrogiovanni2879 If you do find that I’d be very interested to know, thanks!
But a gradient of charges constitutes an electric field..?
Awesomely FUN as well as nuanced & HELPFUL interaction between the two Wonderfully Charged Fields known as ElectroBOOM / Mehdi and Veritasium / Derek respectively !!! BRAVO !!!
The distinction of surface charges matters because the outside of a conductor heats up faster then the inside, especially with high frequency alternating current. You can't design some, especially RF applications without taking these effects, that go outside of the lumbed model into account.
I believe this video omits one crucial insight. In quantum field theory an electron is nothing more than an excitation in the electron field. When we consider an electrical current through a conducting wire then we measure those currents in Amperes. An Ampere id defined as 10^19 electrons per second (give or take a few electron). Now if we consider an average 1,5 mm^2 wire that is an awful lot of electrons in a very small area. Coming back to QFT, if we consider the waveforms of 10^19 electrons in an area of 1,5 mm^2 then their waveforms will overlap to such an extreme extend that we really cannot consider them as individual electrons anymore. All that we have is one massive excitation in the electron field and whatever that actually is, is more analogous to a massive tsunami of energy in the electron field and not a massive amount of individual electrons. Each and every individual electron really ceases to exist.
So we can really not analyse an electrical current in a conducting wire by thinking of individual electrons pushing each other, but we should consider that the battery puts such a tremendous potential across both ends of the wire that we get a surge of energy in the electron field that slowly dissipates to zero as the load uses this energy surge to create work, light and/or heat.
+1
Even Rutherford in his atomic model was cautious to suggest electrons are a unit of charge and not necessarily *physical things*
It is perplexing how so many describe electrons as discrete things, rather than a *model* which approximates observations in experiment.
@@stuartmacintosh4868 very well put! In the video they take the model of an electron being a particle way beyond the limits of that model. This model works really really well when you learn in school about how electricity works, but when you start analysing current in a wire and truly attempt to understand what is going on then you can't do so without considering QFT. They both take the classical view on electrons way out of it's proportion.
@@XEinstein Thanks! Yes I agree it is a common presumption that electrons are actual things, but their supposed mass is more like a 2nd order effect that Newton and Maxwell's work explains.
That Rutherford model (for all it's flaws that QFT exposes!) took science as far as the nuclear age even. Basic electronics and radio can be /sufficiently/ explained with it for a working knowledge. Difficult to say this Rutherford model electronics is completely wrong, just an older (pre-general relativity) explanation.
Very interesting topic. Hope you do that test. Derek's test seemed to show that the initial voltage bump was about 4-5 v almost instantaneously and then an overshoot and drop to the applied ~20V when the main wave made it through the wire. I'd like to understand (1) if the magnitude of this initial bump is impacted by the distance between the wires. If it was 2 m or 4 m rather than 1 m apart, would the initial voltage magnitude decrease or is it somehow independent? And (2) would this initial ~25% of the voltage stay at that level or does it spike and slowly drop until the main wave from the fully wire flow gets to it. And (3) does it transfer not only a measurable voltage across a larger resistor, but does it transfer enough current through a typical light bulb type of resistance to say that it would go "on"
I always imagined it as electrons being "pulled" by the opposite attraction on the other side rather than being "pushed." In other words, once the circuit is closed, the electrons are attracted to go in that direction as there is a venue for them to go through to where they want to go on the other side.
The power source is basically creating a charge imbalance on its side forcing the electrons to want to leave to a balanced location rather than them being "pushed" out.
Which is why copper makes for such as good conductor, because of it's loosely held valence electrons and its outermost zone being only half filled allowing it to carry a vast number of electrons as they make their way to the other side. If that makes sense.
Really interesting discussion! I think at some point in this process of thinking about the 'reality' we have to acknowledge that thinking about electrons as discrete particles is a huge oversimplification in itself and really what we are dealing with is closer to a sort of EM-wave quantum 'soup'. Not that the particle model isn't useful; but sometimes the more complicated model makes the problem seem less confusing.
I really liked your reflected wave superposition explanation of parallel resistors by the way!
"EM-wave quantum soup" sounds like an image inspired more by particle accelerator experiments than by solid state physics. Bu the latter is the right filed of science for answering how conductors actually conduct. Undergraduate E&M courses generally do not try to treat this topic, resorting instead to a few phenomenological results such as Ohm's Law.
Unfortunately, my favored solid state reference has grown legs and crept away to a hiding place, so I have to answer based on memory: metals are excellent conductors because they have a "conduction band" in which the electrons form a "Fermi gas". These are the highly mobile charge carriers. The protons are stuck in a crystal matrix (yes, the basic structure of metal is crystalline -- very small crystals, too small for us to see easily). So they only wiggle and vibrate. So they do not contribute to current.
So in the quasi-static approximation (which works surprisingly well even in the VHF domain for small circuit sizes) you get current from the drift (not thermal) velocities of *moving* particles but the field at any one point does not care about the motion, it only cares about charge balance. So yes, you *can* have balanced net charge with some of them moving. So yes, you can have 0 field inside the conductor, as in electrostatics and non zero current at the same time.
But that, of course, is in the quasi-static approximation. Veritasium's original thought experiment does not satisfy that approximation. Worse yet, since we are talking about such long wires, it is not close enough to reality if you ignore the resistance. Not only that, but you need to take into account inductance and even capacitance as well.
If this reminds you of en.wikipedia.org/wiki/Telegrapher%27s_equations that is because it should remind you of telegraphers equations. The Wikipedia article does not give the exact variation of the Equations to describe the thought experiment, but it gets pretty close: it is easier to modify one of these variations to fit it than it is to start w/ Maxwell's Equations.
It took me years, and building some high speed circuits to understand transients as waves, the way mehdi explains in a few minutes.
After watching tons of old Electroboom videos, I finally found one that came out the same day I watched it.
One of the best feelings I have gotten in a long while.
you know, if you subscribe & hit the bell you'll be notified *every time* one comes out 😁
@@cybergeek11235 That's exactly what I did 😂
I paused my online mechatronics course to spend days watching ElectroBOOM
Electrons in the conduction band (a specific energy range) of a conductor are constantly moving in all directions, a gradient or field merely means that the movement in one direction occurs statistically slightly more often, but this net movement is small in comparison to the all the other movement which mostly cancels out.
I don't like the way this is phrased. Yes, the net movement is puny compared to the chaotic movement, but it's not like the random movement could possibly make any electrons flow against the drift velocity for any appreciable amount of time. The net movement cause by drift velocity is enormous compared to the zero net movement caused by the Fermi velocity.
Nicola, Thats inaccurate, a wire heats up a lot when conducting electricity, so the net movement must be significant. You dont observe heating from your random movements, meaning there is no measurable movement.
"Commendation from NASA for research work at Massachusetts Institute of Technology on the Earth's atmosphere and the Moon's surface for navigation of the Apollo spacecraft to the Moon..
Dr. Milo Wolff has found the structure of the electron consisting of two spherical quantum waves, one moving radially outward and another moving radially inward. The center of the waves is the nominal location of the electron 'particle'. These waves extend infinitely, like charge force. All 'particle' waves mix and contribute to each other, thus all matter of the universe is interrelated by this intimate connection between the fundamental 'particles' and the universe. The natural laws are a direct consequence of this Wave Structure of Matter (WSM), thus WSM underlies all of science."
spaceandmotion
This is a nice eye opener. I always thought from my school lessons that electrons are flowing like a stream of water from the sea of electrons in a conductor material.
But we were taught in biology that electrical charge or action potential propagates in a somewhat similar manner but here electrolytes (Na, Ca, K ions) create charges.
Great discussion! I also love the 4th wall break at 3:20 😂
I am so happy I chose Mechanical Engineering in college rather than Electrical, as after watching you two's videos all my knowledge about electricity would have effed up.
Physics graduate here. Yourur material science explanations are imperfect and I learned some fancy Hameltonian math to better describe dynamics. Orher than maybe not being 100% on every detail engineers are much better trained. You actually learn how to apply stuff way better. I got a degree in Physics and get some of the nitpicks but I never learned the how to part, not like real engineers. I couldn't pass the PE exam and I wouldn't claim to be able. There's a pedantic problem with lots of engineering descriptions. There's no actual problem with not understanding some of these points. The trade off is you actually learn a bunch about how to use/do stuff.
Electrical components can be modelled the same as a mechanical components, e.g a mass on a spring and pneumatic damper behaves the same way as a resistor and a capacitor in a circuit. all engineering fields are more closely related than we think.
@@Ikantspell4 Don't get me wrong. I love these new amendments in understanding of a basic concept. And yes, as you said, the trade off is to actually learn more stuff, but I think it's a trade off (or let's just put it as a challenge) for scientists. For an engineer it's an opportunity rather than trade off to learn something new which is why the most minute of the details are of a great concern for us. Each opportunity that gives a greater output is what we focus on, as you said, with our explanations not being 100% on every detail.
@@alistairmurray626 We learn Heat Transfer with electrical analogy : Temp. diff being same as potential diff., Heat being the same as current, and thermal resistance being the same as electrical resistance, and voila, ohm's law works on heat transfer. Same analogy can be applied for flow of water through pipe.
@@aksajsharma4684 not sure I really think it's so important. Physics students like I was take E&M. In E&m we calculate and derive this stuff so it's not as much as a "gotcha" moment for us like it is for enginerds. Other than the "gotcha" moment I don't think is a big deal. Every year at my university this problem was assigned to engineering students taking physics, every year was confusing, and mostly they all went on to forget it and actually learn how to use electrical models. Here I am with a good understanding of the first principle rules but no applied skill and not working in a field where it matters.
It's about time when physics nerds say " um actually the actual physical phenomenon is more like this:"
The enginerds say " um actually I use this model and made a cool thing work" knowledge only adds and never takes away but maybe knowing such pedantic nuanced quirks is pretty close to useless.
Thinking about this as I get to the 12:29 minute mark in the video. If the electrons were moving on the surface of the wire vs within the wire then you could increase the amount of electricity could be delivered over the wire by either making it hollow thus doubling the surface area for the electrons move on or you could take a wire with a fractal cross section that has the same volume as a round wire and it should carry more charge. In either case the resistance of the wire should be reduced as long as the cross-sectional volume is maintained. However if either of those wires have an increased resistance to the flow of charge then we can tell that the electrons/charge is flowing within the wire itself. Looking around I see that 3M sells copper foil tape that is 1.4 mil 1" tape and that has a cross sectional area of 0.903224 mm^2 and a perimeter of 50.87112 mm and you could compare this to a wire which would be between a 17 and 18 gauge wire which would only have a perimeter of 3.369 mm. This would have to be done in a way that would allow for you to control the amount of heat that the wire is producing as this will by itself increase resistance. This brings up the thought, are round wires better at transferring charge only because of the mass and its ability to transfer heat away. Or would the electricity find a single line on the surface of the tape and run the current down that until it heated up and increased resistance on that path which would cause the current to flow down another path and so on and so forth. I do not know how this experiment could be designed but reading the data sheets it says that those wires can handle 2.9 and 2.3 amps of power transmission respectfully. Finally to finish this up we also need to think about the ability of the electron flow and if a round wire vs the foil is better at making the fields that push the charge along.
I like your tape idea. It would be interesting to try to watch current flow through the tape and wire under an electron microscope. If that is possible.
It's nice to watch experts having a conversation. Makes me feel like I have a lot to learn.
When you do the experiment, could you do parallel wires (as in Derek's) and also a circular loop? It would be interesting to compare the maximum effect vs the minimum
It won't work if the other side of the loop is far away. It is a field influence and will eve work if the loop is cut so the wire is not continuous.
@Mike Foster Hi Mike, the light turns on almost immediately due to the capacitance between the wires on metre apart not from the current travelling around the length of wire. A capacitor does not have a continuous connection inside it. André
I could almost feel the temperature of my brain rise, as I tried to absorb and understand this... again. Your discussion and graphs, especially the vector drawings, helped me understand a lot better. At the end I kept thinking this is like fluid dynamics, which is very difficult to model. Thanks for diving back into this subject.
If we form a circle and all push the one in front of us every one second, are we all going around in circles? That is the difference of propagation through a circular medium vs motion in a circular path.
Fluid dynamics is nothing like electricity. Propqgation of sound in fluids is like electricity. When there is motion, the scale of the phenomenon is much, almost infinitely, larger and the phenomenon is a lot more complex, especially near the edges of the fluid container. When the phenomenon is simple in its measurement. you are looking at propagation, not actual motion.
My head is whistling like a British tea kettle.
Both models may be consistent with each other, but the field approach can be “solved” for practical problems. Perhaps the particle approach can be too? But it’ll come down to fields at some level.
Yeah, good point. I think a lot of engineers learn: electrons -> voltage + current rules -> fields equations to calculate antenna's and emf. They still see the electron as the true master in this interplay. While physicists learn electrons -> voltage + current rules -> solid algebra -> deep understanding of fields and how to calculate them generally. They seem to switch to a field first model, to them the electron is just a charge carrier. It is all very interesting.
Obviously generalizing but seems very clear when you listen to the likes of dave from eevblog versus some professors in physics.
@@kapytanhook I think that’s true too, or at best kept vague as to how charge carriers and fields interact (especially in terms of this electromotive force).
As an engineer I felt that motors and generators are also taught from a very field-based perspective. Once we need to make practical calculations we forget this particle view! Unless the current densities are low, but that’s a whole other thing and probably at the point we neglect carrier-carrier interactions.
Physics undergrads seem to be engaged with fields at a slightly earlier stage than engineers, in terms of Maxwell’s laws. Maybe that shapes our world views.
@@colinedb yeah, motors and generators are very field based. But even there i kind of kept in the back of my mind it's the flowing electrons being the boss of that field
The right hand rule and such are from a perspective of the current, at least how I saw it. Currents make fields that in turn make currents again, the field being a tool for currents to interact. Like how gravity is the field that makes objects pull together, it's easy to get a bit of a particle preference because they are instances
at high frequencies in a real circuit you can't remove all the inductances and capacitances that are never thought of at low frequencies. both systems work but how it's thaught people often forget the true circuit in favor of a more ideal that works at low frequencies and normal conditions where light speed is high enough.
9:00 totally bursted a laugh
What I think would be very interesting for the large loop experiment is changing the position of the load (lightbulb) in the circuit. Because the field explanation suggests to me that the lighbulb right next to the battery should be significantly brighter than one far away since the fields are strongest there
Although now that I am writing the field gradient might be the deciding factor for the brightness which would be constant, I think?
After thinking about it, my conclusion was that you can treat electrons as magnets, monopole magnets.
so they can push eachother and transfer lots of energy without really moving anywhere.
Now I don't know what to make of it, yet I did notice that the final model does explains somewhat why inductors resist to change in current.
I think this video is incredible, apart from the content that is very interesting, you can clearly see the difference between a engineering mind set and a scientific mind set.
And is really fascinating the fact that by viewing both sides you can get a really good understanding of the phenomenon.
The point about charges outside the conductor is an important one for some circuits. A good example is that I learned when setting up my sound system that you want to run the power cable for the amplifier on the opposite side of the car from the audio cable from the head unit to the amplifier. The reason is the power cable draws a strong enough amount of current from the battery that the electromagnetic field will actually cause interference with the audio signal, which in turn causes "dirty sound" as a final result.
As much as I learn from your channel, these collaborations do an amazing job of helping me figure out how such seemingly simple, yet incredibly complex, topics work. Thank you, and keep up the great work!
A variation of this phenomenon happens in programming.
Whenever you began learning how to code you have this weird feeling that the puzzle that is the system you are coding, gets resolved on both ends simmultaneously back and front.
When I began learning reactivity I learned that "regressiveness" is a common aspect of any system, not only AI, this regressive aspect is the one that may be confused, when squinting eyes, as if information is going forward... and this is not wrong.
Regresive functions leave a state change behind them as they move backwards, it is a macro backward motion, composed of micro feedbackloops on each step, the feedback left by the regressive motion is perceived as going forward.
@@johnny5941 the act of coming back from where you came from.
A chain of callbacks that change an inner state can be defined as regressive.
Thanks for making this video Mehdi - please keep up the great work at helping us get closer to truth.
wow
Yellow
Yellow comment
The model of the charge gradient existing only on the surface of the wire is very clear when you remember the wires capacitance
From my understanding, your model averages out the 'reality' model, so it makes sense that would work most of the time. The few cases where this model wouldn't work would likely require to work at the atomic level and I assume this rarely happens unless you work at the CERN or something.
@@chalichaligha3234 Agree. Think about how a capacitor works. It is a charged coupled device based on accumulation of electrons on one place and electron "holes" on the other. A dielectric stress is created which creates the charge and resulting E field. In a DC circuit, a cap will charge to the full voltage applied, causing a current flow until it is fully charged. Then, the current flow stops, but the voltage potential is maintained as long as the circuit has no leakage.
This is awesome! Good work both of you... building quality knowledge for the world like that! It's been awesome to follow this discussion from the first Veritasium video throughout all the reviews and discussions. I think you did a grand work on putting the final conclusions into action! Kudos!
So on the point of when Derek's model would be useful, I'd say it has quite a lot of utility when looking at the low-level function of individual circuit components, and trying to predict measurements of them with high precision. Medhi seems to be heavily focused on a circuit based viewpoint of EM where there's only really wires, resistors, inductions, etc that all have certain numbers attached to them, and they just all kinda work a certain way when you connect them. But you got to remember, that at the lowest level, all of these circuit components act according to Maxwell's equations, and those equations all operate according to fields. And in a lot of ways, you simply *can't* derive accurate results and models of these components without elaborating the gory details.
It was surprise for me by the way that you can't accurately model real-world electrical circuits with just a combination of separate wires, resistors etc. In reality all elements are connected with all elements. To be more precise, even parts of elements with other parts of elements. Example, which I like, is that real inductor have no single resonant frequency - there are many of them. I hope that at some time people will develop better tools to accurately simulate and not less important - visualize such connections.
If you really want an accurate explanation of the way conductors and current works, then Maxwell's equations are not enough -- you really do need quantum mechanics, or more specifically solid-state/condensed matter physics. The proper explanation of the way currents flow is actually fairly complicated, but electrons don't behave as localized objects in a conductor -- they behave more like momentum eigenstates (to a certain degree -- it's complicated).
I hope it's not too late to answer. It feels like both of you are actually right.
We are able to calculate the drift velocity of electrons in a wire and it clearly shows that it's too slow for the current to be carried by electrons without any other interaction.
In the book that veritasium quotes, it says at equilibrium and steady state, but I don't think we can consider the wire in a steady state as soon as we close the switch. To have a steady state you must have the same values (forces, velocity, direction, etc) at different times on the same place, but it doesn't mean it needs to be same particle.
Watching the video gave me the idea that what happens in the wire can be modelled like this:
1. Just like water flowing in a pipe have velocity gradient where it's faster in the middle so electrons have some sort of gradient symmetrical to the center of the wire
2. Since electrons alone move too slow, they act like a Newton's cradle where instead of using the body to transmit energy, the electric fields act as the medium to transfer energy at the speed of light
Using this model, you will see magnetic fields from the movement of electrons and also the power will move at the speed of light (so speed of the "electrical field wave") through the wire
Electrons pushing on each other is the reason there are surface charges in the first place! If you push electrons into the wire, the local excess negative charge repels itself until excess charge is forced onto the surface, and the entire inside is at the same potential.
a great comment, swarmed by bots.
Yup! Electronics create and are affected by fields which create and affect fields which…
I find that very hard to believe.
Electrons are wave/field perturbations that posses mass and charge. (And spin)
You have surface charges in a capacitator as well. Even if you just have one side of the cap, and put the other side to infinity, the charges will move to the surface, to reduce the forces between them, and thus the energy stored in the system.
@@PetraKann This conversation is being had in the context of classical/Maxwellian electromagnetism.
You can model electricity by just electrons moving through a tube, the model can be independent of how it actually works
:|
>:(
if you just delete gravity, a lot of the water pressure equations (for a pipe) are identical to electrical equations.
@@colto2312
Is there a simple way to learn hydraulics?
When I looked up courses they all wanted to start with open-system hydraulics like rivers, but I'm only interested in closed system hydraulics like lift systems in forklifts
@@dustinjames1268 University
@@colto2312
I know the basics of closed hydraulic systems but I want to know enough that I could design my own hydraulic lift
I understand that a big piston pushing on the fluid with a small piston on the 2nd end means the 2nd end gets more force for the same weight, and restricting flow increases pressure and vise versa
But I want to master the topic
I suggest be careful about the claim you make at 23:06. AlphaPhoenix already did the experiment at 1 Km. wire length. He did a great job, and captured the results on a nice storage scope. He showed Veritasium's claim quantitatively, with a small but significant transfer straight across at light speed, and a full transfer after propagation through the wire. He follows his motto well: "Plan A always goes up in smoke."
Great back and forth ! Its increasingly hard to have these type of discussions nowadays ! =)