Ohhhh yeah. Mind blowing point. Also watched your video. This stuff is great. A lot of illustrations are great to understand the circuits energy but man that one made a lot of sense of things. Please keep the videos on electricity coming. I'm a budding Electrician and theory to me is just as important for the future!
im here because i typed "electrons do not exist" in youtube. cause some guy said tesla didnt believe in electrons. now it seems that veritasium guy found your video too.
In this video THE most important thing you should know is that the "electric field" (current) moves at the Speed of Light and physical electrons move or "flow" VERY SLOW thru a conductor (copper wire). Most electricians will tell you its the electrons moving thru the wire at the speed of light! Which is impossible when you think about thousands of mile of electric wire with electrons moving that fast from point A to point B. The friction alone would cause any size wire to melt INSTANTLY! This science TH-cam guy really knows his stuff!!!
HOWARD STERN …Where does the Friction come from……??… The electons being the energy packs , have no course physicality to grind the Conductor....JagtarSinghAujla
@@mohinderjitaujla6245 Electrons flow by jumping from one atom to the next; it takes a bit of voltage to push them along. A bit of energy is lost in the jump, which appears as heat--see the glowing wire in your toaster, made of a material that makes these jumps more difficult. As Stern pointed out, the actual electrons travel quite slowly. The speed is known as "drift velocity", and is characteristic for different materials. For copper, it's about a tenth of a millimeter per second. What does travel at the speed of light is the impulse. Think of a pipe stuffed with ping pong balls. Push a ball in at one end, and the ball at the other end falls out. The balls themselves barely move, but the impulse travels at the speed of sound.
@@danielmarbella1197 Electron movement is ancillary to the electromotive force coursing through the conductor. In fact when its only AC the electrons only jiggle back and forth. Electricians like myself aren't usually amateur physicists, my first degree was electrical engineering.
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Aspiring physician/biomedical engineer here; I've been a subscriber since your centripetal vs centrifugal video ~4 years ago. I was an undergrad at the time. Despite the plethora of physics content on TH-cam, it was obvious to me then that you have an outstanding talent for distilling physics concepts *without* oversimplifying. What makes your channel truly special is the fact that so many others offer a treatment of the subject matter that's so superficial as to be entertaining but practically useless. Like a diamond in the rough, your content somehow manages the seemingly impossible task of providing an entertaining but *useful* treatment of advanced topics that's nevertheless distilled in such a way that makes it as straightforward as possible. Keep doing what you're doing! And thanks. :)
Indeed, levelling us all up by conducting bits of knowledge directly to our brain molecules so by the end of the video we feel energized and charged by a better understanding and get into a positive flow.
Absolutely the best explanations of basic physics I have ever seen AND entertaining. I've been longing for this sort of thing, even though I have a physical sciences degree, you never have time to just put it all together on a practical level. It's hard to explain, but you can ace all your tests and still not really understand this material.
I'm a electrotechnical technician and hopefully a future electrical engineer. I always wondered about how electricity really works from the quantum level to the macroscopic scale. I spent a good time in the last year looking for information in books and websites until develop a good intuition about it, and you basically explained most of it in only 7 minutes! You even talked about the skin effect. Congratulations and thank you for these excellent explanations!
Brother why behaviour Of atoms is different than that of cornor. Atoms are same. What things bring changes in the behaviour of central atoms and edges atoms
Omg I always thought electrons were the ones travelling so fast in a circuit and that's why the circuit components work. I knew there was something more to it when I read that electrons move slowly. Thank you for this.
6:16 The "restriction" is not actually due to "the behavior of the atoms" but due to the changing magnetic field produced by the moving charges (the change is always resisting the change of charge motion). In the middle of the wire the magnetic field is stronger because there is more moving charge around. This effect is not very strong for direct current (the field stabilizes after a short while and then ceases the obstruction as it is no longer changing) but is very strong for alternating current with high frequency (the magnetic field changes all the time). There is a special type of wire called Lorentz wire designed to reduce this effect by bringing the charge from the middle near the skin and back.
This is why I love this channel! Not only have I learned more about electric current, I've corrected a few misconceptions I had as well. Thank you for the knowledge!
I'm almost there I think? OK electrons move slowly (electron drift velocity), but when you get electrocuted (a near instantaneous effect) does that mean you are not getting pumped full of electrons but instead it is your own electrons in your body that speed up from the EM field so essentially you are being cooked by your own electrons' increase in drift velocity? What about lightning bolts? Lightning bolts are just the creation and collapse of a giant EM field?
Correct. It's your own electrons that kill you. As for lightning, yes, a giant EM field is needed to turn the air into a conductor. Drift velocity depends on a lot of material factors though, so I'm not sure what the speed of the charge is in lightning (off hand).
Exactly! As for lightning bolts, they work similar way. It's just a giant spark. The quirk in that scenario is the fact, that a lightning bolt is not just charge moving through a conductor. The electric field actually physically charges air (an insulator) into plasma (a conductor). So the bolt actually makes its own conductor in front of it as it goes and carries the electric field with it.
Exactly. EM is in every sort of matter (if my fingers do not slip through the keyboard and the table, it is because of electromagnetism, nothing else: elementary particles as such are too tiny to matter on their own, chemistry is also electromagnetism) just that most commonly in equilibrium, neutral or almost so. It's when an inbalance of energy (charge to be precise) happens when the current flows and the "push", the "pressure", the "energy" burns through. And then you wish it was cold water rather than electricity....
First time I was actually able to see how this works. And that the wave travels at the speed of light I didn’t know. Professors were always using the water hose analogy, which I kind of got but not fully. Thanks, Nick!
I was never quite sure why that was the case when I was at polytechnic. You need to understand hydraulics in the first place. I think it's a throwback to the early days of electrical theory when the principles of hydraulics were already well understood. However, after the first year I had a brilliant professor (Professor Stefani) teaching electrical theory. No need to mention hydraulics. He made everything crystal clear.
Love your videos! Master auto mechanic here, whenever I do electronic diagnosing, my peers call me a "wizard", but I always think of myself as a plumber when looking for shorts, opens, and high resistance in circuits 🙃
Really pleasing surprised. This was a very good explanation of how current flows in conductors that anyone can understand, even without any knowledge of electromagnetism physics or electrical engineering. You also used the appropriate terminology giving it to the audience in a way very easy to understand. It is not so easy to find on TH-cam people that makes videos like you. I have seen people explaining complicated subjects showing their understanding on the subject, but then failing in using the correct terminology and, therefore, creating confusion in how things are really working. Very well done. Kudos!!!
I've watched this video series a few times now. I really love how you've managed to make very clear, what high school failed to do thirty five years ago. Thank you!
Thanks! I'll mention humbly that in some of your videos, the flow of explanations is kind of interrupted with humorous breaks too often and then I repeatedly fail to catch the explanations. This one was super clear I didn't loose focus.
Ok, I've recently realized how much I love this channel for its uniqueness among science channels. Very concise and articulate as well as purely entertaining. Reminds me of when I was a kid watching Bill Nye the science guy, but with better science! Anyways, keep up the good work, I've already shared your channel with a few people I know. I hope it gets bigger. It definitely deserves it.
You do a great job producing unique content on topics that are done to death all over TH-cam on other channels. Your ability to distill complex concepts down to their most fundamental parts without sacrificing rigor is a sign of true mastery.
dx dp < h does not say you cannot measure both. You can measure both but there is a limit on the precision. However, h is a very small number so you have to get to really precise measures before their product is less than h.
I know some people consider you pedantic (cough cough minutephysics) but I really appreciate your disclosures about the ambiguity of our "categories." Reality is almost always a complex spectrum of properties. I've said it before, a key principle that has been nailed home to me from your channel is that our black and white categories are only accurate to an extent. Reality is always more complex and gray. This principle is not only important for science, but significant for all of life. So I'd say you're cautious rather than pedantic.
6:50 I love the Hydraulic Analogy! I'm a lonely electrical guy surrounded by mechanical guys. Whenever I try to explain electrical concepts, I just get blank stares until I start invoking hydraulic equivalents. Then the pinched pipes go off.
The one thing that is completely different is that water does not travel outside the pipe; while electrons also move outside the wire. Hense, why insulators are required to keep things safe. The higher the voltage, the more the electrons travel outside the wire. That's why there is less resistance with higher voltage, and therefore, less heat generated.
Ohh how I wish I had you as a teacher when I was a teenager. You have the best way possible to break down questions and looking at them from a rational point of view. Your focus on the language aspect is a huge part of that, I think. Thanks once again for a great video. Keep up the good work.
I have to say that this video was perfect. I've graduated out of my physics undergraduate classes a few years ago and during the courses, many times I found myself lost and not understanding some basics. It wasn't until recently that I'm preparing some educational content for teens that I found myself questioning the basics. If I would have been shown this video at the beginning of a college physics class, many concepts would have been cleared up for me but instead I dived deep into homework with sophisticated calculations without fully understanding some basics. Your style of mad scientist is definitely an acquired taste for me, but I now have to say that it's really caught my attention. I would like to say that I'll be using this video in my future lessons. Keep doing this awesome job that you've been doing!
Beautifully done! This presentation should be 'required reading' for all students (and teachers) of electrochemistry -- where the long-standing fairy-tale has been that electrons go whizzing about in the beaker and wires to make electrolysis happen.
The water flow analogy I feel like works even better when you consider the flow as a river. Even conductors have a certain amount of resistance, which, in a river could be analogous to rocks and other things blocking the flow. Also, when water goes around objects in the river there can be a slight backflow of water particles like when water "spins" back toward the object it is flowing around. Even though some water particles may go upstream temporarily the flow as a whole is still going downstream.
Fun fact: silicon is used as a semi conductor because of that gap. This gap can be used for many things, for example, a type of semi conductor, a photoresistor, allows electricity to flow if there is a photon in the gap making a bridge for the flow.
I remember one of the first classes of physics 3 (book Moysés Nussenzveig) one of the concepts stroke me the most was this that the electrons actually don't move that fast, only the current does. Also, in my classes about semiconductors, I never really understood or got an intuition about the gap, It was a "shut up and just calculate" thing. This video both remembered that wonderful class and gave me a better intuition. Love it.
It's better to think of the "flow" as a _shockwave_ instead of a flow. The electrons are like the water molecules and the water is the electric field... but instead of water flowing through a pipe, the pipe's ends are sealed and the water is mostly stationary (while also somehow extending outside the walls of the pipe, but that's a whole other mind-boggle). Then you tap one end of the pipe and that'll send a shockwave through the water from one end to the other. A ripple of waves that moves THROUGH the water, moving each molecule of the water slightly, but the WAVE is what moves fast from one end to the other, dissipating in strength along the way. That's exactly how electricity behaves. Direct Current is like tapping repeatedly and sending uniform shockwaves again and again in one direction... current being how frequently you're hitting it, with voltage being how hard you hit it with each tap to create bigger or smaller waves. Alternating Current is like switching back and forth between tapping and sucking a little to create a ripple of suction instead of a forward pulse. It pulls the water back a little bit in a wave of suction that would travel forwards through the pipe, pulling the water molecules backwards a bit along the way, instead of pushing them forward a bit. Do that back and forth 50 or 60 times a second and the motion creates more energy, aka bigger waves, by jarring the water back and forth really fast. The waves get bigger more easily this way than if you try to do it by pushing it in one direction repeatedly. With DC, you have to tap REALLY hard on one end to get the waves to stay big by the time they get to the other end of the pipe. But with AC, you can just shake it back and forth with relative ease to get big waves happening at the other end.
@@AWSVids I've been trying to understand how current works, considering that electrons don't actually move that fast but waves of energy across them does. Thinking that the current could be interpreted as the amount of waves per unit of time is just so helpful for me. Your comment is underrated
Thank you for your hard work thank you for this Channel. A lot of channels stray from their original subject or just get unnecessary. You are still where you started in a positive way
This is a phenomenal video. I just discovered your channel today, and it is great. I got a little lost after you talked about drift velocity vs speed at which the electric field changes. Time to look up how electric fields work.
Ok, so here's the thing. Electromagnetism between electromagnets doesn't rely on the spin of electrons. You can calculate entirely from combining the forward flow of electrons (relative to the protons in the nuclei of the atoms in the wires) with the effects of special relativity. But it bothers me that to get a very strong relativistic effect from something moving as slowly as electrons do, that means that the forces caused by electric charge must be so huge they're hard to think about. So when you mentioned that the electric field moves at the speed of light, I wondered if I had it wrong, does the motion of the field cause the electromagnetic effects, not the motion of electrons relative to the protons in the wire? I don't see how that's possible, since the protons matter too, but I thought I should ask. And what IS the field? 1) I thought it was a fraction of the speed of light in wire, though a significant fraction 2) I figured it was something like pressure in water - it represents electrons forming a fluid that isn't compressable. How right or wrong are these?
What a crazy channel ;) However, it surprisingly fits perfectly. Every joke has a meaning, is in context and helps in the understanding. Great work! Thank you very much!
1:55 "But the 3 best conductors are silver copper and gold, in that order" You forgot to mention that it is only true at standard temperature and pressure! Some elements become superconductors at very low temperatures.
Hi and thank you for your video. I hope this topic makes sense and you can help. This is what I understand (please allow numerical approximations): 1. Electrons move in a conductor at a speed anywhere near the speed of light. 2. Electrons gain actual velocity (drift) only when supply is ON. Propagation of EM field is about 270.000 km/s. 3. For DC, drift velocity can be calculated. Now, am I right to say that, in AC, actual average velocity is zero? That's because in a PERIOD, electrons move back and forth. I could calculate the drift in half a period, but in a period would be zero. Correct? This means there is no actual transmissions of electrons from source to load, right? Under the assumption above, why we keep talking about "power transmission"? As a matter of fact, there is nothing moving from source to load. Electrons simply move back and forth while performing work. Also, under the considerations above, can anyone explain the concept of "reactive power going back and forth from source to load" in cases where power factor is lesser than 1? Thank you very much in advance!
Your list of conductors reminded me of a fun historical fact. During WWII, the Manhattan project needed lots of wiring for cyclotrons to purify fissile uranium. With all the copper already gone for the war effort, they ended up getting a bunch of silver out of the nation's precious metal supply and melting it down into wire for their cyclotrons. (And melting it back into bullion when they were through with it, of course.)
You, sir, are the first person who can explain what happens inside of a wire clearly. I have watched lots of other videos but they are all confusing in certain aspects. I'm actually a pre-service science teacher. To be honest, I got pretty good marks for physics when I was in high school but no one has ever taught me about this so my conception about current is inaccurate or even incorrect. And now I will try my best to pass this knowledge down to future students. Thank you so much.
I would change or add to your water analogy chart: Battery = Water reservoir Alternator or Generator = Water Pump Voltage = Water Pressure Current = Volume of Water ( need bigger pipe) Switch = Water Valve on off Resistance = Lower Water Flow at a give Pressure. Pressure and Volume of water too high pipe bursts (melt wire if voltage/current too high) Wire = Pipe (wire gauge vs pipe diameter. // wire gauge counter intuitive smaller wire gauge larger the wire)
Yes, if the individual strands are insulated from each other, say by a coat of varnish. "Litz wire" is braided from individual varnished strands, so the current is forced to flow through the whole cross section. It's used to wind high current inductors for frequencies up to about one megaherz. For very high powers, say in radio transmitters, you just use copper tubing--all skin and no center.
@@50srefugee Ackhually, you use the copper tubing mostly because of the high frequency of the radio signals and not because of the high powers. The Skin Effect is a function of frequency, not Power(or Voltage or Current) mostly.
Very good explanation, you even touch on good'ol brownian motion. Maybe you could do a video on the actual speed of light versus what we call "speed of light" just to show how a perturbation on a field propagates at exactly C
One of the things that opened my mind to electromagnetism is that there’s no such thing as an insulator, and that everything is magnetic. “Insulators” are just extremely poor conductors. With enough voltage & amperage, all matter will conduct. (Perfect conductors do exist - superconductors. If you get a circuit going in one, it’ll run forever, with no additional energy required.) Magnetism works the same way. All matter is magnetically active. Although it’s possible for some materials to be perfectly magnetic (superconductors are also supermagnets), there’s no such thing as a material that’s 100% magnetically inert. Which means that matter is an effect or epiphenomenon of electromagnetism. Also, I prefer to use the “propagate” rather than “flow” or “current.” Imagine a circular river, like the lazy river ride at a water park. Electricity is not really like the flow of water around the circle. It’s more like propagating a transverse wave around the circle of water. The water itself is not actually flowing, but the wave is “moving” (or can be treated as though it’s moving). The energy that creates the waveform is continuously oscillating the water molecules in one direction, even though no significant amount of water is actually changing its position along the circle.
01:30 Oh yes, I agree about categories. Just because we create a box doesn't mean things have to fit in it. Crappy boxes like "bush". When is it a "plant", when is it a "tree"? That problem only exists because you created the box in the first place. Oh, and I kept thinking of other comments, but then they were covered, so I am humbled there.
Transfers electrons from one molecule to the next. Over charged molecule transfers it's electrons to the next and so forth. Some materials resist the transfer and energy is released as heat.
@@danfreeman9079 one doubt for me is when an electron gets transferred doesn't it make the ion stable . So how does the electron transfer happen continuously so that current flows continuously? I have difficulty in understanding it
so if you suddenly stop the flow of the charge do you get a spike in voltage, or amps or what ever the right term would be? similar to waterhammer when you shut a valve?
Yes you would. In fact, this is commonly used to create high voltage spikes in stuff like halogen lightbulbs or boost converter. Note that in case of electricity, the magnetic field is analogous to the momentum of water in waterhammer.
Water analogy is best avoided.....I learned that in first semester of college electricity. The water hammer effect of closing a valve is due to flowing mass of water being suddenly stopped. Mass of electron is too small to matter, and as the prof says, electron moves at approx 5cm/hr. Charge has no mass. When a switch is opened, think about that in slow motion. At first, when break is incredibly small, some little bit of charge will still move across the gap like in a capacitor, but then with a little more space or air gap in the break charge will stop dead, and the distance needed to stop charge dead depends on the driving voltage entering the switch...the higher the voltage, or so-called potential charge, the larger the gap needed to stop charge dead. With high voltages >1000v in air, the charge will ionize air molecules and a little tiny spark of bolt of lightning can be seen jumping the gap as it is opened...then when opened far enough that flow of charge via ionized air will be stopped dead. Next, inductance must be considered. If there is inductance in wires connecting to the switch, upon opening the switch there will be a spike of voltage in the opposite polarity to the what had been the applied voltage. Magnetic energy stored in the inductance returns into the wires as charge quite suddenly. Any length of wire has some inductance, the longer the wire the more the inductance. The lower the resistance of the wire, due to short length or large gauge, the more forceful will be the magnetically induced charge and voltage of the spike...yet this is not so simple. Imagine the wires as super-conductors...then no voltage can be induced because everywhere in the wire the voltage will be zero. So in any circuit there is something like a trade off or balance of resistance and inductance that will determine the voltage of the spike. And of course that all depends on the amount of current that was "flowing"....certainly the larger the current flow the larger will be the spike, all things considered and noting that superconductor wires are only used in research facilities. Now, btw, the inductance in the wires or actual inductors in the circuit does sort of equate with the mass of water flowing in the pipe. More electric current flow, more magnetic field, more spike upon opening the switch due to field collapse. In some circuits a snubber capacitor is connected across the switch contacts. Snubber capacitor is combination of a high voltage tolerating capacitor with a small value resistor, small enough not to heat up but large enough to dissipate the voltage spike as heat, and thus there will be little or no spark when the switch is opened. Snubber capacitor prolongs the useful life of switch contacts in two ways 1) eliminates spark, cuz the voltage spike flows through the capacitor and resistor, and thus eliminates carbon buildup on switch contacts 2) sparking, if not supressed, will pit the switch contacts which will degrade the actual contact area and thus increase the resistance of switch, which will lead to switch heating if current is large, leading to oxidation of contacts leading to more heat....then switch failure. The better analogy for conceptualizing electricity is the mechanical analogy where resistance =brake, capacitance=spring, inductance=mass, force=voltage, current=displacement, time=time.
I went to school to be an Electrician. Our instructor used water as an analogy to help us understand the current flow. Since than, I have wondered about this.
Dielectric current (displacement current) can be felt with high voltage electrostatic fields. Especially when the field is suddenly discharged (grounded) the pressure field is extremely strong, capable of deforming thick metal sheets. This is THE source of power behind true free electricity devices.
That definitely helped my understanding of electricity, great video! I'm a plumber so I know a lot about water but not a lot about charge. Hey could you do a video on the Venturi effect? That would be so cool!
Aye. I watch a bunch of science stuff like this and I love that you just get to the point and break it down in "normal" terms. Love the graphics love it all. Keep it up and keep us smarter
as i remember it, "free electron flow" is actually an exchange of electrons from molecule to molecule in a given conducting media. the media, copper in this example is a stationary conductor but the molecules of copper in the conductor have "loose" electrons and when one is added another is released and allowed to move to the next molecule knocking off another electron and so on creating electron flow.
I see. Because it confused me a bit because I remember reading things like Cooper pair (I think), and things like topology in quantum system that just doesn't make things easier for me to understand. Thank you .
@@ScienceAsylum Maybe a whole episode could be dedicated just to superconductors. For example that because there is no resistance they are not subject to Ohm's Law. Only current can flow through superconductors, and therefore power or work can only be transferred by interaction with magnetic fields as described by Ampère's Circuital Law (with Maxwell's Additions). The amount of current is limited not by resistance heating up the superconductor but by the Meissner Effect. (Note that this comment may raise as many questions as it answers.)
Imagine it like this: you have a fan connected to a water mill on a stream. When the water moves from one end to the other, it pushes the water mill and the fan runs, creating wind. That is DC. When the water flows back and forth instead, it still pushes the water mill and the fan still runs, back and forth of course, but still creates wind. That is AC. If you watch a light bulb connected to AC in extreme slow motion, you can see it doesn't light up all the time but rather blink with extremely fast speed, similar to the fan running and stopping then running backward. Of course that is the simple case of the incandescent light bulb. In case of AC motors like electric fans, they have a special design that involves magnetism to keep the motor running in one direction despite the AC current.
Where is the energy in water current: in "push", in pressure. Same thing with electricity: no matter if it goes forth and back, it does exert "pressure" (sorta), it transfers electromagnetic energy and for many purposes like a lightbulb or a resistance radiatior that is enough. However for other purposes like computers, it's not, so a transformer must change from AC to DC (and also down regulate the voltage, etc.) The reason why AC is used is because, in spite of Edison, who fought for DC and lost, it proved best for transport, I won't pretend I understand the details of this but it's the real reason: energy efficiency in transport by wire.
It doesn't cancel out with simple AC because it's not happening at the same time. It alternates - first in one direction and then the other and back and forth and back and forth, hence the name, alternating current. It's *exactly* like a pendulum in that regard. And just like a pendulum, we measure the amount of time the current spends on each swing. The pendulum on a grandfather clock is _about_ a meter long, and it swings once every second. In the US, the current swing for home electricity happens in 1/60th of a second - or 1 cycle (of back and forth) per 1/60th of a second. Or put more conveniently, 60 cycles per each second, and even more conveniently, we use Hertz (abbreviated Hz, pronounced just like hurts) - Hz means *per second,* it's the inverse of time (1/t) - so we refer to it as 60 Hz. Elsewhere, house current flows at 50 Hz. Just as seconds measures time, Hz measures frequency. A pendulum does not cancel itself out, neither does simple AC current. Not all alternating current is single-frequency in nature. The audio signal in your speaker wires has a broad range of frequencies (theoretically from 20 Hz to 20,000 Hz but in reality, not as extreme) flowing at the same time. The complex waveform is exactly what happens with air pressure when you speak or sing or musical instruments play notes and in those cases, some frequencies DO cancel while others get together and do the opposite, they add together, and everything in between, at each successive fraction of a second. In music, the signal came that way in the air before it was recorded, with the cancelations and reinforcements already built-in. *But you do not need an air signal for that - synthesizers can sound like drums, pianos, organs, violins, and voices exactly by creating the cancelations and reinforcements using nothing but alternating current flows.* Another analogy to a pendulum is a circle. This video shows how circles can be arranged to make any complex patterns. One turn of a circle in one second is 1 Hz. th-cam.com/video/ds0cmAV-Yek/w-d-xo.html Fourier in that video is the guy who figured it out centuries ago and the math is the Fourier series. That's all you need to know to put my explanation and the video together to see how awesome the effects are that you've been experiencing all of your life. Hope that helps. PS - Very good question!
As EE I must say most part of this video is accord to the math and physics models we use nowadays to describe electrical interactions, one observation I must do about the drifting velocity and current being a function of charge and time, is that electrons, are indeed charge particles, and since one is pushing into another the movement effect is almost immediate at the end point of the conductor, I say almost, because in more advance subjects that have more practical implications we go over the speed of propagation of those electric fields caused by those tiny electrical particles that state of the art math and physics models call electrons.
It may play a role but my guess is that as the strands are placed next to each other forming in practice a single mass the effect mostly cancels out. The main reason I believe is that multi-strand wires are more flexible and resistent to fracture and even you can use the various strands to make braids and knots at your convenience when tying them to some device like a plug without requiring any welding.
@@LuisAldamiz yeah the main reason is more flexibility but I do wonder how it effects the conductivity. I always thought single big core got less resistance as it acts like bigger pipe, or wider road.
@@atranas6018 To avoid skin losses there are special wire called "Litze wire" where the strands are individually insulated. This relevant in AC electric motors when the motor controller switching frequency is in the kHZ range, like in electric vehicles and using such a wire can improve motor efficiency 4-5%.
to understand a wire and what goes on inside it you have to use calculus. You imagine any wire made up of infinitely small strands, each with it's own magnetic field. The field of one strand opposes the field of all stands adjacent to it, thus creating inductance. And not just immediately adjacent but a little further than that, but just a little further as the intensity of the mag field reduces according to the inverse square law...in other words it peeters out. So while the current in each strand sums up, the mag field opposing the current does not sum up....its less, so to speak. Near the perimeter of a strand the mag field is less because, for instance, the outer most ( imaginary infinitesimal) strands are not surrounded by other strands...at least on one side, the outside of the strand. There is less inductance near the perimeter of a strand. Consider now stranded, but not insulated wire. Although the strands are all touching each other (assume tightly bound or twisted together) because each strand is round there will be some space where they are not touching. Where not touching the inductance will be slightly less. WIth dc current the slightly less inductance of stranded wire vs solid wire hardly matters....except perhaps for very long wires, but still it is in almost all cases insignificant. But with ac currents the matter of solid vs stranded is more significant because ac currents are more susceptible to inductance as the frequency rises. Even the thin insulation of individual strands of Litz wire does give some improvement due to the small increase of distance between strands. Audiophiles prefer Litz wire to connect phonograph pickup to preamp, and such connections are typically only 2 to 3 feet in length, the whole idea there being to decrease inductance to facilitate high frequencies which are not just part of the high frequency instruments but part of all percussive sounds as well, for instance even the plucking of strings by finger of bow. The reproduction of the French horn may not benefit much from Litz wires as it is intended to be non-percussive.
The main reason for stranded is said to be flexibility and ability to be routed. So it is used in cars and home appliances, etcetera where movement and or vibration is expected. I was told in school that stranded has a tendency of overcoming the skinning effect, but I think that's not demonstrable, and it certainly wouldn't be worth the difference in manufacturing steps.
If you haven't already, can you please do a video about metallic bonds, or why metallic elements are much more conductive than non-metallic elements? Thank you!
It depends on the academic level of your final physics course at high school. The teacher also has to cover all of the other subjects such as light, sound, heat, mechanics. Post-secondary education will normally go into greater depth.
@@adamroach4538 i'm second year undergrad, if you have questions about modules you can ask, the subjects are really interesting but second year quantum mechanics is hands down the best for me. Can't wait for 3rd year QM, bring on the pain physics I double dare you. Check out the quantum eraser experiment for some time-traveling electrons and a sprinkle of existential crisis. :)
I'm about to call you "my personal knowledge wrecking man" since you have wrecked my learning about electricity: it has been taught to me that electrons move in a wire at the speed of light... while you gave them only 4cm/hour! Can steady electrons cause all of the miracles we know and enjoy everywhere (speaking about electronics)? In the other hand, your job is pretty valuable.
I used to have some prejudice about this channel because of the way the guy speaks (as if to children and adolescents) , but it is really, really goooooood 👏👏👏
Hey SA, Veritasium posed a question: if a battery is attached to a wire that is 2 ly long (1/2 ly in each direction before coming back to a light bulb), how long will it take for the bulb to turn on after closing the connection? The battery is 1m from the bulb and assume no resistance in the wire. a) 1ly b) 2ly c) 1/c d) none of the above
I was discussing this recently with a civil engineer. The way I explained it was that the absence of electrons is what is flowing. In other words the "holes" they leave behind when they move from one atom to the other. Hence why electrons "flow" from a negative charge to a positive and current in the opposite direction. This explains why a charge can move at the speed of light or maybe even beyond. The electrons, which have mass, only have to move the length between atoms at a time while the ripple effect of the holes moves instantaneously. This also explains why wires with a smaller diameter get hotter. Because, relative to a larger wire, more of the electrons within the slice the size of that diameter, have to move to fill the holes of the next slice. It also explains the skin effect. The holes in the middle of the conductor can get filled from every direction. The electrons of the insulator don't move, so the holes at the circumference can't get filled from the outside, which gives the electrons at the circumference more opportunity to move.
There, I have now watched every video on your channel as far back as TH-cam will allow. What I've learned is: We as a species have figured out a lot about how our Universe operates, however, we still seem to be missing a few fundamental ingredients to truly understand what we are dealing with. At least in the current moment. I also think we should abandon many models like relativity or Quantum mechanics and see what happens if we start from scratch. To me, using flawed models is like using a broken clock. Sure, it might be right twice a day, but I want a clock that's always right. I feel like clinging to these models is really holding us back, a new perspective or new point of view is definitely what we need at this point.
_"We as a species have figured out a lot about how our Universe operates, however, we still seem to be missing a few fundamental ingredients to truly understand what we are dealing with."_ This is a good summary. _"I also think we should abandon many models like relativity or Quantum mechanics and see what happens if we start from scratch."_ Unfortunately, that's what relativity and quantum mechanics are: us starting from scratch. We realized our simple models were wrong on a fundamental level and we tried all the alternative simple models showing they were also wrong, so all we have left are the weird ones. On top of that, those weird ones work INCREDIBLY well!
@@ScienceAsylum I can't wait to see if the "Theory of Everything" is something profound that nobody saw coming or if it is something mundane that was right under our nose all along!
This is a really good intro to the Drude model of conduction. Unfortunately, this model will leave a lot of unanswerable questions when someone starts probing around with it. For example, based on the Drude model, conductivity should be relatively the same for any single valence electron material with overlapping bands...but it isn't. This is one example of where the Drude model breaks down. When QM considerations are taken into account, it contradicts some of the statements that naturally arise in the Drude model, such as the velocity of conduction electrons being really slow. In typical conduction, there is certainly a drift velocity from the electric field, but that drift velocity is very small compared to the thermal velocity. The result is that most of the drifting electrons still cancel each other out when considering a macroscopic current, but there is a small group that move (at a specific velocity) that are not compensated by the thermal motion...electrons at the fermi velocity. Those electrons are moving quite fast, approximately 1.5*10^6m/s in copper. Why differnt materials have different conductivities comes down to the structure of their Brillouin zone, details of thier band structure, and their population density near the fermi level. Really interesting stuff! For a good intro to this, I recommend Electronic Properties of Materials 4th ed. by Rolf E. Hummel.
Great video just like all. Great for people who can never rest until the answers make sense down to the last detail. Just wanted to make a remark about the flaws in analogies specifically how water pressure ( analogy of voltage) fails to explain voltage drop in an electrical circuit. A resistor (pinched pipe ) will likely have a different voltage (drop)over it than the wires and other components connected in the circuit under normal circumstances. Pressure in a pinched pipe will be the same as the rest of the pipes (non pinched) connected to it, I would have thought.
Re chart @6:54. Technically a pressure activated valve is a subset of transistors known as Field Effect Transistors. Plain transistor transistors are current adjusted.
OMG, I always remembered that my teacher in highschool said something that electrons travel across the outer surface of the conductor. I actually once searched for this but never found any information about it. Then I came across this video (after like 5 years?) and boom, skin effect! I bet that he meant that. For the entire time I was kind of sure that either I remember something wrong, or he was wrong. But turns out he was right. Thank you for this video, it was informative, well done, and well explained! I love such videos where you go into details, instead of "voltage is U=RI, enjoy".
At 5:18, you mentioned electric field travels at 'c' and subsequently all charge flows at same rate. So, does it mean electron also flow at speed of light or is it just that energy travels at this speed and gets the bulb switched on.
Anyone who is here from Veritasium's video on circuit energy, you're actually looking for this video of mine: th-cam.com/video/C7tQJ42nGno/w-d-xo.html
Ohhhh yeah. Mind blowing point. Also watched your video. This stuff is great. A lot of illustrations are great to understand the circuits energy but man that one made a lot of sense of things. Please keep the videos on electricity coming. I'm a budding Electrician and theory to me is just as important for the future!
im here because i typed "electrons do not exist" in youtube. cause some guy said tesla didnt believe in electrons. now it seems that veritasium guy found your video too.
X @@genkidama7385 v y
These videos about electricity and fields only confuse me further. I now have no idea whatsoever how electricity works.
This one is a good follow up though! Thank you for this! Really helped me understand better than veritasium’s video!
In this video THE most important thing you should know is that the "electric field" (current) moves at the Speed of Light and physical electrons move or "flow" VERY SLOW thru a conductor (copper wire). Most electricians will tell you its the electrons moving thru the wire at the speed of light! Which is impossible when you think about thousands of mile of electric wire with electrons moving that fast from point A to point B. The friction alone would cause any size wire to melt INSTANTLY! This science TH-cam guy really knows his stuff!!!
HOWARD STERN …Where does the Friction come from……??…
The electons being the energy packs , have no course physicality to grind the Conductor....JagtarSinghAujla
It's common sense. Every medium have some resistance...
@@mohinderjitaujla6245 Electrons flow by jumping from one atom to the next; it takes a bit of voltage to push them along. A bit of energy is lost in the jump, which appears as heat--see the glowing wire in your toaster, made of a material that makes these jumps more difficult.
As Stern pointed out, the actual electrons travel quite slowly. The speed is known as "drift velocity", and is characteristic for different materials. For copper, it's about a tenth of a millimeter per second.
What does travel at the speed of light is the impulse. Think of a pipe stuffed with ping pong balls. Push a ball in at one end, and the ball at the other end falls out. The balls themselves barely move, but the impulse travels at the speed of sound.
@@50srefugee the ping pong reference helped me, thanks!
@@danielmarbella1197 Electron movement is ancillary to the electromotive force coursing through the conductor. In fact when its only AC the electrons only jiggle back and forth. Electricians like myself aren't usually amateur physicists, my first degree was electrical engineering.
Aspiring physician/biomedical engineer here; I've been a subscriber since your centripetal vs centrifugal video ~4 years ago. I was an undergrad at the time. Despite the plethora of physics content on TH-cam, it was obvious to me then that you have an outstanding talent for distilling physics concepts *without* oversimplifying. What makes your channel truly special is the fact that so many others offer a treatment of the subject matter that's so superficial as to be entertaining but practically useless. Like a diamond in the rough, your content somehow manages the seemingly impossible task of providing an entertaining but *useful* treatment of advanced topics that's nevertheless distilled in such a way that makes it as straightforward as possible. Keep doing what you're doing! And thanks. :)
This is wonderful to hear! Thanks! :-D
So true! (Not any sort of engineer myself but I have to agree in all the rest).
Indeed, levelling us all up by conducting bits of knowledge directly to our brain molecules so by the end of the video we feel energized and charged by a better understanding and get into a positive flow.
Hey! You are a biomedical engineer, I would really use your help. Is there any way I can contact you?
Absolutely the best explanations of basic physics I have ever seen AND entertaining. I've been longing for this sort of thing, even though I have a physical sciences degree, you never have time to just put it all together on a practical level. It's hard to explain, but you can ace all your tests and still not really understand this material.
I'm a electrotechnical technician and hopefully a future electrical engineer. I always wondered about how electricity really works from the quantum level to the macroscopic scale. I spent a good time in the last year looking for information in books and websites until develop a good intuition about it, and you basically explained most of it in only 7 minutes! You even talked about the skin effect. Congratulations and thank you for these excellent explanations!
You are not electrotechnical. You are ITI. but great ambition. But believe me practical or onsite knowledge will help you.
Brother why behaviour Of atoms is different than that of cornor. Atoms are same. What things bring changes in the behaviour of central atoms and edges atoms
Quantum effects can be seen on the macro scale too. Quantum entanglement has been observed between macroscopic diamond crystals.
What is your work like?
Omg I always thought electrons were the ones travelling so fast in a circuit and that's why the circuit components work. I knew there was something more to it when I read that electrons move slowly. Thank you for this.
You're very welcome 🤓
6:16 The "restriction" is not actually due to "the behavior of the atoms" but due to the changing magnetic field produced by the moving charges (the change is always resisting the change of charge motion). In the middle of the wire the magnetic field is stronger because there is more moving charge around. This effect is not very strong for direct current (the field stabilizes after a short while and then ceases the obstruction as it is no longer changing) but is very strong for alternating current with high frequency (the magnetic field changes all the time). There is a special type of wire called Lorentz wire designed to reduce this effect by bringing the charge from the middle near the skin and back.
This is why I love this channel! Not only have I learned more about electric current, I've corrected a few misconceptions I had as well. Thank you for the knowledge!
I'm almost there I think? OK electrons move slowly (electron drift velocity), but when you get electrocuted (a near instantaneous effect) does that mean you are not getting pumped full of electrons but instead it is your own electrons in your body that speed up from the EM field so essentially you are being cooked by your own electrons' increase in drift velocity? What about lightning bolts? Lightning bolts are just the creation and collapse of a giant EM field?
Correct. It's your own electrons that kill you. As for lightning, yes, a giant EM field is needed to turn the air into a conductor. Drift velocity depends on a lot of material factors though, so I'm not sure what the speed of the charge is in lightning (off hand).
Exactly!
As for lightning bolts, they work similar way. It's just a giant spark. The quirk in that scenario is the fact, that a lightning bolt is not just charge moving through a conductor. The electric field actually physically charges air (an insulator) into plasma (a conductor). So the bolt actually makes its own conductor in front of it as it goes and carries the electric field with it.
@@ScienceAsylum Thanks, sensei!
@@KohuGaly Awesome.
Exactly. EM is in every sort of matter (if my fingers do not slip through the keyboard and the table, it is because of electromagnetism, nothing else: elementary particles as such are too tiny to matter on their own, chemistry is also electromagnetism) just that most commonly in equilibrium, neutral or almost so. It's when an inbalance of energy (charge to be precise) happens when the current flows and the "push", the "pressure", the "energy" burns through.
And then you wish it was cold water rather than electricity....
First time I was actually able to see how this works. And that the wave travels at the speed of light I didn’t know. Professors were always using the water hose analogy, which I kind of got but not fully. Thanks, Nick!
I was never quite sure why that was the case when I was at polytechnic. You need to understand hydraulics in the first place. I think it's a throwback to the early days of electrical theory when the principles of hydraulics were already well understood.
However, after the first year I had a brilliant professor (Professor Stefani) teaching electrical theory. No need to mention hydraulics. He made everything crystal clear.
Love your videos! Master auto mechanic here, whenever I do electronic diagnosing, my peers call me a "wizard", but I always think of myself as a plumber when looking for shorts, opens, and high resistance in circuits 🙃
*"I always think of myself as a plumber..."*
That's so interesting ...and also valid.
Really pleasing surprised. This was a very good explanation of how current flows in conductors that anyone can understand, even without any knowledge of electromagnetism physics or electrical engineering. You also used the appropriate terminology giving it to the audience in a way very easy to understand. It is not so easy to find on TH-cam people that makes videos like you. I have seen people explaining complicated subjects showing their understanding on the subject, but then failing in using the correct terminology and, therefore, creating confusion in how things are really working. Very well done. Kudos!!!
What do electrons say when they move? "Charge!"
Assuming they know how energetic everyone is: Marco!
Watts that you say? That pun is revolting. Is it your most current joke. Try to resist the temptation to make bad puns.
Larry Patterson
Don’t be so NEGATIVE.
@@definesigint2823 Now that was really boronic! What are the other electrons supposed to answer?! "Polar"???
They don't move in the normal sense. They occupy a certain position and at some other point of observation (bit of time) they are at another.
I've watched this video series a few times now. I really love how you've managed to make very clear, what high school failed to do thirty five years ago. Thank you!
You're very welcome. Glad I could help 🙂
Wonderfull! Don't disappear, man!
but in what way? What if he dies?
@@Lyle-xc9pg
He's not allow to die anymore.
Kkkkk...
Gabriel Telles Lins Gonçalves Taveira
kkk
@@Lyle-xc9pg - We'll just have to make a clone...
Hey guys,I think they already have LOL.psGreat Little video's.thanks to who ever for them.cheers
Thanks! I'll mention humbly that in some of your videos, the flow of explanations is kind of interrupted with humorous breaks too often and then I repeatedly fail to catch the explanations. This one was super clear I didn't loose focus.
Man, your videos make me fall in love with science again and again!!!! 😌
For the Science of God read Srimad Bhagavatam by A.C.Bhaktivedanta Swami Prabhupada. You may not realise you have diamonds in your own backyard.
Ok, I've recently realized how much I love this channel for its uniqueness among science channels. Very concise and articulate as well as purely entertaining. Reminds me of when I was a kid watching Bill Nye the science guy, but with better science! Anyways, keep up the good work, I've already shared your channel with a few people I know. I hope it gets bigger. It definitely deserves it.
You contradict yourself😙
love how you have standard so high that never recur to the outdated nuclear/planetary atom models, opting instead for a more accurate representation.
Yeah, I can't do the circular orbit model. It's just so wrong.
@@ScienceAsylum especially for the topic of this video.
I feel sorry for Rutherford and Bohr though.
@@ScienceAsylum Maybe explain the energy bands in materials?
You do a great job producing unique content on topics that are done to death all over TH-cam on other channels. Your ability to distill complex concepts down to their most fundamental parts without sacrificing rigor is a sign of true mastery.
Thanks!
dx dp < h does not say you cannot measure both. You can measure both but there is a limit on the precision. However, h is a very small number so you have to get to really precise measures before their product is less than h.
I know some people consider you pedantic (cough cough minutephysics) but I really appreciate your disclosures about the ambiguity of our "categories." Reality is almost always a complex spectrum of properties. I've said it before, a key principle that has been nailed home to me from your channel is that our black and white categories are only accurate to an extent. Reality is always more complex and gray. This principle is not only important for science, but significant for all of life. So I'd say you're cautious rather than pedantic.
6:50 I love the Hydraulic Analogy! I'm a lonely electrical guy surrounded by mechanical guys. Whenever I try to explain electrical concepts, I just get blank stares until I start invoking hydraulic equivalents. Then the pinched pipes go off.
The one thing that is completely different is that water does not travel outside the pipe; while electrons also move outside the wire. Hense, why insulators are required to keep things safe.
The higher the voltage, the more the electrons travel outside the wire. That's why there is less resistance with higher voltage, and therefore, less heat generated.
You delivery is loved by my 2 children ages 7 and 10 they like your clones and repeat your words. You have a way of connecting with people.
This is wonderful to hear. Thank you :-D
Ohh how I wish I had you as a teacher when I was a teenager.
You have the best way possible to break down questions and looking at them from a rational point of view. Your focus on the language aspect is a huge part of that, I think.
Thanks once again for a great video. Keep up the good work.
I have to say that this video was perfect. I've graduated out of my physics undergraduate classes a few years ago and during the courses, many times I found myself lost and not understanding some basics. It wasn't until recently that I'm preparing some educational content for teens that I found myself questioning the basics. If I would have been shown this video at the beginning of a college physics class, many concepts would have been cleared up for me but instead I dived deep into homework with sophisticated calculations without fully understanding some basics.
Your style of mad scientist is definitely an acquired taste for me, but I now have to say that it's really caught my attention. I would like to say that I'll be using this video in my future lessons. Keep doing this awesome job that you've been doing!
Beautifully done! This presentation should be 'required reading' for all students (and teachers) of electrochemistry -- where the long-standing fairy-tale has been that electrons go whizzing about in the beaker and wires to make electrolysis happen.
Your name says it all. When I hear something from Lucid, stuff in my mind become lucid.
The water flow analogy I feel like works even better when you consider the flow as a river. Even conductors have a certain amount of resistance, which, in a river could be analogous to rocks and other things blocking the flow. Also, when water goes around objects in the river there can be a slight backflow of water particles like when water "spins" back toward the object it is flowing around. Even though some water particles may go upstream temporarily the flow as a whole is still going downstream.
Fun fact: silicon is used as a semi conductor because of that gap. This gap can be used for many things, for example, a type of semi conductor, a photoresistor, allows electricity to flow if there is a photon in the gap making a bridge for the flow.
I remember one of the first classes of physics 3 (book Moysés Nussenzveig) one of the concepts stroke me the most was this that the electrons actually don't move that fast, only the current does. Also, in my classes about semiconductors, I never really understood or got an intuition about the gap, It was a "shut up and just calculate" thing. This video both remembered that wonderful class and gave me a better intuition. Love it.
It's better to think of the "flow" as a _shockwave_ instead of a flow. The electrons are like the water molecules and the water is the electric field... but instead of water flowing through a pipe, the pipe's ends are sealed and the water is mostly stationary (while also somehow extending outside the walls of the pipe, but that's a whole other mind-boggle). Then you tap one end of the pipe and that'll send a shockwave through the water from one end to the other. A ripple of waves that moves THROUGH the water, moving each molecule of the water slightly, but the WAVE is what moves fast from one end to the other, dissipating in strength along the way. That's exactly how electricity behaves.
Direct Current is like tapping repeatedly and sending uniform shockwaves again and again in one direction... current being how frequently you're hitting it, with voltage being how hard you hit it with each tap to create bigger or smaller waves. Alternating Current is like switching back and forth between tapping and sucking a little to create a ripple of suction instead of a forward pulse. It pulls the water back a little bit in a wave of suction that would travel forwards through the pipe, pulling the water molecules backwards a bit along the way, instead of pushing them forward a bit. Do that back and forth 50 or 60 times a second and the motion creates more energy, aka bigger waves, by jarring the water back and forth really fast. The waves get bigger more easily this way than if you try to do it by pushing it in one direction repeatedly. With DC, you have to tap REALLY hard on one end to get the waves to stay big by the time they get to the other end of the pipe. But with AC, you can just shake it back and forth with relative ease to get big waves happening at the other end.
@@AWSVids I've been trying to understand how current works, considering that electrons don't actually move that fast but waves of energy across them does. Thinking that the current could be interpreted as the amount of waves per unit of time is just so helpful for me. Your comment is underrated
Thank you for your hard work thank you for this Channel.
A lot of channels stray from their original subject or just get unnecessary.
You are still where you started in a positive way
I like the Category Alert. And how you explain stuff like that.
This is a phenomenal video. I just discovered your channel today, and it is great.
I got a little lost after you talked about drift velocity vs speed at which the electric field changes. Time to look up how electric fields work.
This video is part of an entire playlist :-) th-cam.com/play/PLOVL_fPox2K9MtRv68T_cmWwQUbg9YR4F.html
Ok, so here's the thing. Electromagnetism between electromagnets doesn't rely on the spin of electrons. You can calculate entirely from combining the forward flow of electrons (relative to the protons in the nuclei of the atoms in the wires) with the effects of special relativity.
But it bothers me that to get a very strong relativistic effect from something moving as slowly as electrons do, that means that the forces caused by electric charge must be so huge they're hard to think about.
So when you mentioned that the electric field moves at the speed of light, I wondered if I had it wrong, does the motion of the field cause the electromagnetic effects, not the motion of electrons relative to the protons in the wire? I don't see how that's possible, since the protons matter too, but I thought I should ask.
And what IS the field?
1) I thought it was a fraction of the speed of light in wire, though a significant fraction
2) I figured it was something like pressure in water - it represents electrons forming a fluid that isn't compressable.
How right or wrong are these?
Another, now unsurprisingly, brilliant video!
What a crazy channel ;) However, it surprisingly fits perfectly. Every joke has a meaning, is in context and helps in the understanding. Great work! Thank you very much!
reminds me of our college days when we first studied em theory and maxwell equations. it changed my perspective forever.
1:55 "But the 3 best conductors are silver copper and gold, in that order"
You forgot to mention that it is only true at standard temperature and pressure!
Some elements become superconductors at very low temperatures.
I've seen a lot of explanations around this topic. This is one of the most accurate I have come across.
Hi and thank you for your video.
I hope this topic makes sense and you can help.
This is what I understand (please allow numerical approximations):
1. Electrons move in a conductor at a speed anywhere near the speed of light.
2. Electrons gain actual velocity (drift) only when supply is ON. Propagation of EM field is about 270.000 km/s.
3. For DC, drift velocity can be calculated.
Now, am I right to say that, in AC, actual average velocity is zero? That's because in a PERIOD, electrons move back and forth. I could calculate the drift in half a period, but in a period would be zero. Correct? This means there is no actual transmissions of electrons from source to load, right?
Under the assumption above, why we keep talking about "power transmission"? As a matter of fact, there is nothing moving from source to load. Electrons simply move back and forth while performing work.
Also, under the considerations above, can anyone explain the concept of "reactive power going back and forth from source to load" in cases where power factor is lesser than 1?
Thank you very much in advance!
Your list of conductors reminded me of a fun historical fact. During WWII, the Manhattan project needed lots of wiring for cyclotrons to purify fissile uranium. With all the copper already gone for the war effort, they ended up getting a bunch of silver out of the nation's precious metal supply and melting it down into wire for their cyclotrons. (And melting it back into bullion when they were through with it, of course.)
I didn't know this. Thanks!
Nice video. I always wondered if the water analogy was accurate or not. And naturally, I liked this video! :-)
You, sir, are the first person who can explain what happens inside of a wire clearly. I have watched lots of other videos but they are all confusing in certain aspects. I'm actually a pre-service science teacher. To be honest, I got pretty good marks for physics when I was in high school but no one has ever taught me about this so my conception about current is inaccurate or even incorrect. And now I will try my best to pass this knowledge down to future students. Thank you so much.
You are very welcome!
I would change or add to your water analogy chart:
Battery = Water reservoir
Alternator or Generator = Water Pump
Voltage = Water Pressure
Current = Volume of Water ( need bigger pipe)
Switch = Water Valve on off
Resistance = Lower Water Flow at a give Pressure. Pressure and Volume of water too high pipe bursts (melt wire if voltage/current too high)
Wire = Pipe (wire gauge vs pipe diameter. // wire gauge counter intuitive smaller wire gauge larger the wire)
Current flows easier through the edge of a conductor vs the center? Does that mean that stranded wire is better than one solid wire?
Yes, if the individual strands are insulated from each other, say by a coat of varnish. "Litz wire" is braided from individual varnished strands, so the current is forced to flow through the whole cross section. It's used to wind high current inductors for frequencies up to about one megaherz. For very high powers, say in radio transmitters, you just use copper tubing--all skin and no center.
@@50srefugee Ackhually, you use the copper tubing mostly because of the high frequency of the radio signals and not because of the high powers. The Skin Effect is a function of frequency, not Power(or Voltage or Current) mostly.
@@electrified4251 True, but I'm speaking of high-power RF versus low power, which can use Litz wire.
Stranded wire can handle more amperage than solid wire. Electricians know this
@@johnrice1943 I am not finding support for this in the code. Cite?
A video on Schrodinger's cat thought experiment please!
I see a lot of misconception about that.
Very good explanation, you even touch on good'ol brownian motion. Maybe you could do a video on the actual speed of light versus what we call "speed of light" just to show how a perturbation on a field propagates at exactly C
One of the things that opened my mind to electromagnetism is that there’s no such thing as an insulator, and that everything is magnetic. “Insulators” are just extremely poor conductors. With enough voltage & amperage, all matter will conduct. (Perfect conductors do exist - superconductors. If you get a circuit going in one, it’ll run forever, with no additional energy required.)
Magnetism works the same way. All matter is magnetically active. Although it’s possible for some materials to be perfectly magnetic (superconductors are also supermagnets), there’s no such thing as a material that’s 100% magnetically inert.
Which means that matter is an effect or epiphenomenon of electromagnetism.
Also, I prefer to use the “propagate” rather than “flow” or “current.” Imagine a circular river, like the lazy river ride at a water park. Electricity is not really like the flow of water around the circle. It’s more like propagating a transverse wave around the circle of water. The water itself is not actually flowing, but the wave is “moving” (or can be treated as though it’s moving). The energy that creates the waveform is continuously oscillating the water molecules in one direction, even though no significant amount of water is actually changing its position along the circle.
01:30 Oh yes, I agree about categories. Just because we create a box doesn't mean things have to fit in it. Crappy boxes like "bush". When is it a "plant", when is it a "tree"? That problem only exists because you created the box in the first place.
Oh, and I kept thinking of other comments, but then they were covered, so I am humbled there.
Thank you lucid, amazing animations. Just don't disappear lol.
l am a electric and electrical engineer student and i always looked for a channel like this. and finally , l found it .
Thank you Lucid, very cool.
Transfers electrons from one molecule to the next. Over charged molecule transfers it's electrons to the next and so forth. Some materials resist the transfer and energy is released as heat.
@@danfreeman9079 one doubt for me is when an electron gets transferred doesn't it make the ion stable . So how does the electron transfer happen continuously so that current flows continuously? I have difficulty in understanding it
Solved all the confusions. thanks a lot to have taken the time and put in the endeavour.
Completely agree with everything, as an Electrical Engineer!
Wire Grabby Clone is having a bad day.
Indeed.
so if you suddenly stop the flow of the charge do you get a spike in voltage, or amps or what ever the right term would be? similar to waterhammer when you shut a valve?
You would get a momentary spike in voltage.
Yes you would. In fact, this is commonly used to create high voltage spikes in stuff like halogen lightbulbs or boost converter.
Note that in case of electricity, the magnetic field is analogous to the momentum of water in waterhammer.
Water analogy is best avoided.....I learned that in first semester of college electricity. The water hammer effect of closing a valve is due to flowing mass of water being suddenly stopped. Mass of electron is too small to matter, and as the prof says, electron moves at approx 5cm/hr. Charge has no mass. When a switch is opened, think about that in slow motion. At first, when break is incredibly small, some little bit of charge will still move across the gap like in a capacitor, but then with a little more space or air gap in the break charge will stop dead, and the distance needed to stop charge dead depends on the driving voltage entering the switch...the higher the voltage, or so-called potential charge, the larger the gap needed to stop charge dead. With high voltages >1000v in air, the charge will ionize air molecules and a little tiny spark of bolt of lightning can be seen jumping the gap as it is opened...then when opened far enough that flow of charge via ionized air will be stopped dead.
Next, inductance must be considered. If there is inductance in wires connecting to the switch, upon opening the switch there will be a spike of voltage in the opposite polarity to the what had been the applied voltage. Magnetic energy stored in the inductance returns into the wires as charge quite suddenly. Any length of wire has some inductance, the longer the wire the more the inductance. The lower the resistance of the wire, due to short length or large gauge, the more forceful will be the magnetically induced charge and voltage of the spike...yet this is not so simple. Imagine the wires as super-conductors...then no voltage can be induced because everywhere in the wire the voltage will be zero. So in any circuit there is something like a trade off or balance of resistance and inductance that will determine the voltage of the spike. And of course that all depends on the amount of current that was "flowing"....certainly the larger the current flow the larger will be the spike, all things considered and noting that superconductor wires are only used in research facilities.
Now, btw, the inductance in the wires or actual inductors in the circuit does sort of equate with the mass of water flowing in the pipe. More electric current flow, more magnetic field, more spike upon opening the switch due to field collapse.
In some circuits a snubber capacitor is connected across the switch contacts. Snubber capacitor is combination of a high voltage tolerating capacitor with a small value resistor, small enough not to heat up but large enough to dissipate the voltage spike as heat, and thus there will be little or no spark when the switch is opened.
Snubber capacitor prolongs the useful life of switch contacts in two ways 1) eliminates spark, cuz the voltage spike flows through the capacitor and resistor, and thus eliminates carbon buildup on switch contacts 2) sparking, if not supressed, will pit the switch contacts which will degrade the actual contact area and thus increase the resistance of switch, which will lead to switch heating if current is large, leading to oxidation of contacts leading to more heat....then switch failure.
The better analogy for conceptualizing electricity is the mechanical analogy where resistance =brake, capacitance=spring, inductance=mass, force=voltage, current=displacement, time=time.
@@rh001YT A water analogy is perfectly appropriate for introductory concepts and macro-analysis.
I went to school to be an Electrician. Our instructor used water as an analogy to help us understand the current flow.
Since than, I have wondered about this.
Dielectric current (displacement current) can be felt with high voltage electrostatic fields. Especially when the field is suddenly discharged (grounded) the pressure field is extremely strong, capable of deforming thick metal sheets.
This is THE source of power behind true free electricity devices.
That definitely helped my understanding of electricity, great video! I'm a plumber so I know a lot about water but not a lot about charge. Hey could you do a video on the Venturi effect? That would be so cool!
great video as always!
Ahha this is guy is legend. THEM nerdy as side shots get me all the time. Hahahha😃😃😄
Aye. I watch a bunch of science stuff like this and I love that you just get to the point and break it down in "normal" terms. Love the graphics love it all. Keep it up and keep us smarter
Thanks!
as i remember it, "free electron flow" is actually an exchange of electrons from molecule to molecule in a given conducting media. the media, copper in this example is a stationary conductor but the molecules of copper in the conductor have "loose" electrons and when one is added another is released and allowed to move to the next molecule knocking off another electron and so on creating electron flow.
That's the simple explanation, but reality is way more interesting 🤓
0:05 Do not try this at home.
haha xD
You don't say.
This guy is crazy lol so glad i found this channel.
What about superconductors?
Best conductors... *at room temperature.
@@ScienceAsylum wait, i thought that we need to cool them down?
Yes, I meant that as a correction to what I said in the video: silver, copper, and gold are the best conductors _at room temperature._
I see.
Because it confused me a bit because I remember reading things like Cooper pair (I think), and things like topology in quantum system that just doesn't make things easier for me to understand.
Thank you .
@@ScienceAsylum Maybe a whole episode could be dedicated just to superconductors. For example that because there is no resistance they are not subject to Ohm's Law. Only current can flow through superconductors, and therefore power or work can only be transferred by interaction with magnetic fields as described by Ampère's Circuital Law (with Maxwell's Additions). The amount of current is limited not by resistance heating up the superconductor but by the Meissner Effect.
(Note that this comment may raise as many questions as it answers.)
Hey! I learnt something today, Thanks for taking the time to put this video together.
This is THE BEST channel for explaining this stuff... I have tried lots of them. Thank u... From a college dropout
Thanks! I do my best.
This man is making me CRAZY!! I cant see current the same way i use to see it.... cucu cucu
If AC is alternating current then how current can move by going backwards and forwards which cancel out ?
Imagine it like this: you have a fan connected to a water mill on a stream. When the water moves from one end to the other, it pushes the water mill and the fan runs, creating wind. That is DC. When the water flows back and forth instead, it still pushes the water mill and the fan still runs, back and forth of course, but still creates wind. That is AC. If you watch a light bulb connected to AC in extreme slow motion, you can see it doesn't light up all the time but rather blink with extremely fast speed, similar to the fan running and stopping then running backward.
Of course that is the simple case of the incandescent light bulb. In case of AC motors like electric fans, they have a special design that involves magnetism to keep the motor running in one direction despite the AC current.
Where is the energy in water current: in "push", in pressure. Same thing with electricity: no matter if it goes forth and back, it does exert "pressure" (sorta), it transfers electromagnetic energy and for many purposes like a lightbulb or a resistance radiatior that is enough.
However for other purposes like computers, it's not, so a transformer must change from AC to DC (and also down regulate the voltage, etc.) The reason why AC is used is because, in spite of Edison, who fought for DC and lost, it proved best for transport, I won't pretend I understand the details of this but it's the real reason: energy efficiency in transport by wire.
It doesn't cancel out with simple AC because it's not happening at the same time. It alternates - first in one direction and then the other and back and forth and back and forth, hence the name, alternating current. It's *exactly* like a pendulum in that regard. And just like a pendulum, we measure the amount of time the current spends on each swing. The pendulum on a grandfather clock is _about_ a meter long, and it swings once every second. In the US, the current swing for home electricity happens in 1/60th of a second - or 1 cycle (of back and forth) per 1/60th of a second. Or put more conveniently, 60 cycles per each second, and even more conveniently, we use Hertz (abbreviated Hz, pronounced just like hurts) - Hz means *per second,* it's the inverse of time (1/t) - so we refer to it as 60 Hz. Elsewhere, house current flows at 50 Hz. Just as seconds measures time, Hz measures frequency.
A pendulum does not cancel itself out, neither does simple AC current.
Not all alternating current is single-frequency in nature. The audio signal in your speaker wires has a broad range of frequencies (theoretically from 20 Hz to 20,000 Hz but in reality, not as extreme) flowing at the same time. The complex waveform is exactly what happens with air pressure when you speak or sing or musical instruments play notes and in those cases, some frequencies DO cancel while others get together and do the opposite, they add together, and everything in between, at each successive fraction of a second. In music, the signal came that way in the air before it was recorded, with the cancelations and reinforcements already built-in.
*But you do not need an air signal for that - synthesizers can sound like drums, pianos, organs, violins, and voices exactly by creating the cancelations and reinforcements using nothing but alternating current flows.*
Another analogy to a pendulum is a circle. This video shows how circles can be arranged to make any complex patterns. One turn of a circle in one second is 1 Hz.
th-cam.com/video/ds0cmAV-Yek/w-d-xo.html
Fourier in that video is the guy who figured it out centuries ago and the math is the Fourier series. That's all you need to know to put my explanation and the video together to see how awesome the effects are that you've been experiencing all of your life.
Hope that helps.
PS - Very good question!
because electrons are polite and dont shove each other
Blox117, technically speaking, they _do_ shove each other. That's why they all move together in the circuit.
Anyone here after Derek’s latest video?
This is the video you actually want: th-cam.com/video/C7tQJ42nGno/w-d-xo.html
This is one of those situations where watching the 7 minute video three times is more beneficial than watching the 21 minute video once.
As EE I must say most part of this video is accord to the math and physics models we use nowadays to describe electrical interactions, one observation I must do about the drifting velocity and current being a function of charge and time, is that electrons, are indeed charge particles, and since one is pushing into another the movement effect is almost immediate at the end point of the conductor, I say almost, because in more advance subjects that have more practical implications we go over the speed of propagation of those electric fields caused by those tiny electrical particles that state of the art math and physics models call electrons.
Here after Derek's video...
This is the one you want: th-cam.com/video/C7tQJ42nGno/w-d-xo.html
@@ScienceAsylum yes... Watching that,... But thanks.. 🥳🤓
Due of the skin effect, does a multi-strand wire is more conductive than a similar size single core wire?
It may play a role but my guess is that as the strands are placed next to each other forming in practice a single mass the effect mostly cancels out. The main reason I believe is that multi-strand wires are more flexible and resistent to fracture and even you can use the various strands to make braids and knots at your convenience when tying them to some device like a plug without requiring any welding.
@@LuisAldamiz yeah the main reason is more flexibility but I do wonder how it effects the conductivity. I always thought single big core got less resistance as it acts like bigger pipe, or wider road.
@@atranas6018 To avoid skin losses there are special wire called "Litze wire" where the strands are individually insulated. This relevant in AC electric motors when the motor controller switching frequency is in the kHZ range, like in electric vehicles and using such a wire can improve motor efficiency 4-5%.
to understand a wire and what goes on inside it you have to use calculus. You imagine any wire made up of infinitely small strands, each with it's own magnetic field. The field of one strand opposes the field of all stands adjacent to it, thus creating inductance. And not just immediately adjacent but a little further than that, but just a little further as the intensity of the mag field reduces according to the inverse square law...in other words it peeters out. So while the current in each strand sums up, the mag field opposing the current does not sum up....its less, so to speak.
Near the perimeter of a strand the mag field is less because, for instance, the outer most ( imaginary infinitesimal) strands are not surrounded by other strands...at least on one side, the outside of the strand. There is less inductance near the perimeter of a strand.
Consider now stranded, but not insulated wire. Although the strands are all touching each other (assume tightly bound or twisted together) because each strand is round there will be some space where they are not touching. Where not touching the inductance will be slightly less.
WIth dc current the slightly less inductance of stranded wire vs solid wire hardly matters....except perhaps for very long wires, but still it is in almost all cases insignificant. But with ac currents the matter of solid vs stranded is more significant because ac currents are more susceptible to inductance as the frequency rises. Even the thin insulation of individual strands of Litz wire does give some improvement due to the small increase of distance between strands. Audiophiles prefer Litz wire to connect phonograph pickup to preamp, and such connections are typically only 2 to 3 feet in length, the whole idea there being to decrease inductance to facilitate high frequencies which are not just part of the high frequency instruments but part of all percussive sounds as well, for instance even the plucking of strings by finger of bow. The reproduction of the French horn may not benefit much from Litz wires as it is intended to be non-percussive.
The main reason for stranded is said to be flexibility and ability to be routed. So it is used in cars and home appliances, etcetera where movement and or vibration is expected.
I was told in school that stranded has a tendency of overcoming the skinning effect, but I think that's not demonstrable, and it certainly wouldn't be worth the difference in manufacturing steps.
WE WANT MAXWELL'S EQUATIONS!!!
I can't just jump into that. I have to work up to it.
@@ScienceAsylum I understand, sorry. I'm too excited :)) Also, I want to show my appreciation for all the videos. Thank you a lot!
Merry Chrissy & a happy new year , Trev..
You too!
If you haven't already, can you please do a video about metallic bonds, or why metallic elements are much more conductive than non-metallic elements? Thank you!
I didn’t like this video...
I Loved it! 👍🏻😎👍🏻
But I obviously gave it a “TH-cam like”. 😉
Just come here, when I see the science asylum comment on veritasium video on the same topic
This is probably the video you actually wanted to watch: th-cam.com/video/C7tQJ42nGno/w-d-xo.html
I've been lied to my entire life. You would think they would teach you that in high school.
It depends on the academic level of your final physics course at high school. The teacher also has to cover all of the other subjects such as light, sound, heat, mechanics. Post-secondary education will normally go into greater depth.
@@georgeknowles8762 I'm taking physics when school starts back in January.
@@adamroach4538 If you are interested in physics, have you checked in the double split experiment?
@@TFYS-QA Yes, I know what that is
@@adamroach4538 i'm second year undergrad, if you have questions about modules you can ask, the subjects are really interesting but second year quantum mechanics is hands down the best for me. Can't wait for 3rd year QM, bring on the pain physics I double dare you. Check out the quantum eraser experiment for some time-traveling electrons and a sprinkle of existential crisis. :)
This guy makes things so simple to understand.He is a pure genius.
These explainers do an awesome job of explaining electricity and as such really stand out!
whos here after reading his comment from veritasium
This is the video you want: th-cam.com/video/C7tQJ42nGno/w-d-xo.html
@@ScienceAsylum thx
I wish I had your brain
*A zombie*
Yeah..
Thinking like that is like desiring the destination rather than the journey it took to reach the destination.
You do, just apply time and hard work.
I'm sure he will rent it to you for parties and special occasions.
I'm about to call you "my personal knowledge
wrecking man" since you have wrecked my learning about electricity: it has been taught to me that electrons move in a wire at the speed of light... while you gave them only 4cm/hour! Can steady electrons cause all of the miracles we know and enjoy everywhere (speaking about electronics)?
In the other hand, your job is pretty valuable.
Yes, _most_ of the things that occur in our world are because of electrons.
I used to have some prejudice about this channel because of the way the guy speaks (as if to children and adolescents) , but it is really, really goooooood 👏👏👏
One of the best explaining in this topic ! Keep up the awesome work!
Hey SA,
Veritasium posed a question: if a battery is attached to a wire that is 2 ly long (1/2 ly in each direction before coming back to a light bulb), how long will it take for the bulb to turn on after closing the connection? The battery is 1m from the bulb and assume no resistance in the wire.
a) 1ly
b) 2ly
c) 1/c
d) none of the above
Looks like he posted his video. It's pretty consistent with what I said in this video: th-cam.com/video/C7tQJ42nGno/w-d-xo.html
@@ScienceAsylum I knew that video would be the key!!!! You are the cheat code to Veritasium
I was discussing this recently with a civil engineer. The way I explained it was that the absence of electrons is what is flowing. In other words the "holes" they leave behind when they move from one atom to the other. Hence why electrons "flow" from a negative charge to a positive and current in the opposite direction. This explains why a charge can move at the speed of light or maybe even beyond. The electrons, which have mass, only have to move the length between atoms at a time while the ripple effect of the holes moves instantaneously.
This also explains why wires with a smaller diameter get hotter. Because, relative to a larger wire, more of the electrons within the slice the size of that diameter, have to move to fill the holes of the next slice.
It also explains the skin effect. The holes in the middle of the conductor can get filled from every direction. The electrons of the insulator don't move, so the holes at the circumference can't get filled from the outside, which gives the electrons at the circumference more opportunity to move.
There are no holes in his explanation. It is confusing me as well.
There, I have now watched every video on your channel as far back as TH-cam will allow. What I've learned is: We as a species have figured out a lot about how our Universe operates, however, we still seem to be missing a few fundamental ingredients to truly understand what we are dealing with. At least in the current moment. I also think we should abandon many models like relativity or Quantum mechanics and see what happens if we start from scratch. To me, using flawed models is like using a broken clock. Sure, it might be right twice a day, but I want a clock that's always right. I feel like clinging to these models is really holding us back, a new perspective or new point of view is definitely what we need at this point.
_"We as a species have figured out a lot about how our Universe operates, however, we still seem to be missing a few fundamental ingredients to truly understand what we are dealing with."_
This is a good summary.
_"I also think we should abandon many models like relativity or Quantum mechanics and see what happens if we start from scratch."_
Unfortunately, that's what relativity and quantum mechanics are: us starting from scratch. We realized our simple models were wrong on a fundamental level and we tried all the alternative simple models showing they were also wrong, so all we have left are the weird ones. On top of that, those weird ones work INCREDIBLY well!
@@ScienceAsylum I can't wait to see if the "Theory of Everything" is something profound that nobody saw coming or if it is something mundane that was right under our nose all along!
I really like your videos. Your a great teacher, and look forward to seeing them daily. Keep it up ,cause I'm loving learning daily.
This is a really good intro to the Drude model of conduction. Unfortunately, this model will leave a lot of unanswerable questions when someone starts probing around with it. For example, based on the Drude model, conductivity should be relatively the same for any single valence electron material with overlapping bands...but it isn't. This is one example of where the Drude model breaks down. When QM considerations are taken into account, it contradicts some of the statements that naturally arise in the Drude model, such as the velocity of conduction electrons being really slow. In typical conduction, there is certainly a drift velocity from the electric field, but that drift velocity is very small compared to the thermal velocity. The result is that most of the drifting electrons still cancel each other out when considering a macroscopic current, but there is a small group that move (at a specific velocity) that are not compensated by the thermal motion...electrons at the fermi velocity.
Those electrons are moving quite fast, approximately 1.5*10^6m/s in copper.
Why differnt materials have different conductivities comes down to the structure of their Brillouin zone, details of thier band structure, and their population density near the fermi level. Really interesting stuff!
For a good intro to this, I recommend Electronic Properties of Materials 4th ed. by Rolf E. Hummel.
seen 2 of your vids. love them. i am a theoretical physicist. you never stop learning in physics. thx. well done.
Glad you like them! 🤓
Great video just like all. Great for people who can never rest until the answers make sense down to the last detail. Just wanted to make a remark about the flaws in analogies specifically how water pressure ( analogy of voltage) fails to explain voltage drop in an electrical circuit. A resistor (pinched pipe ) will likely have a different voltage (drop)over it than the wires and other components connected in the circuit under normal circumstances. Pressure in a pinched pipe will be the same as the rest of the pipes (non pinched) connected to it, I would have thought.
Re chart @6:54. Technically a pressure activated valve is a subset of transistors known as Field Effect Transistors. Plain transistor transistors are current adjusted.
OMG, I always remembered that my teacher in highschool said something that electrons travel across the outer surface of the conductor. I actually once searched for this but never found any information about it. Then I came across this video (after like 5 years?) and boom, skin effect! I bet that he meant that. For the entire time I was kind of sure that either I remember something wrong, or he was wrong. But turns out he was right. Thank you for this video, it was informative, well done, and well explained! I love such videos where you go into details, instead of "voltage is U=RI, enjoy".
Glad I could help 🙂
At 5:18, you mentioned electric field travels at 'c' and subsequently all charge flows at same rate. So, does it mean electron also flow at speed of light or is it just that energy travels at this speed and gets the bulb switched on.