The hidden link between electricity and magnetism

[@lindosland]

At last! You see, about 40 years ago my friend Tony explained this to me (we both did electronics degrees at Bangor University, UCNW earlier) saying how amazing it was - there is only an electric field. I never forgot this, but I could not remember the details, only the gist of it. I asked him about it some ten years ago, but he insisted he had no recollection of such a thing. I searched in vain for a simple explanation. Now I have it! I wish I could tell Tony - but sadly he died three years ago, though this is one of the many memories of him that lives on in me! Thanks.

[@tenoarrive841]

All things return to God lady everything that is done is not for man's vanity but he who created all things! The AMEN TRINITY AMEN ✨🌠📕🙏♾️

[@lindosland]

@@tenoarrive841 Sad that the Enlightenment went over some peoples heads.

[@DosezDaily]

Regards ✍️

[@commanderthorkilj.amundsen3426]

Videos have made the visualization and comprehension of the principles involved in this, and many other phenomena so much easier than when I learned this in the 60’s. By making particular subject matter like electromagnetism, relativity, and quantum physics accessible even to dull minds, it has reduced the relative value and accomplishments of my fellow colleagues at our institution.

[@ncedwards1234]

@@commanderthorkilj.amundsen3426 At what institution?

[@ianheams2599]

I am an ignorant electrician and I tend to think visually. I very much enjoyed this video and the visual representation of electrons and proton nuclei in a copper wire. I even followed the ideas visually represented when special relativity was introduced. I found the mathematical equations beautiful and entertaining but was lost within about 30 seconds. I guess I need to do a maths course, probably several maths courses! And I need to see more of your videos. So please continue the good work. With much appreciation......

[@lunam7249]

I'm a Post Ph.d EE.... and I commend your enthusiasm...there are a lot of good vids on youtube....start your technical journey..algebra is good enough to get 80% of high tech stuff...it's fun..

[@varunahlawat9013]

That would be very exciting if you could also think mathematically. I too, encourage you to pursue some mathematics courses for that.

[@kevincleary627]

I am sure you aren't an ignorant electrician, but an excellent electrician. I would hire you any time.

[@deserthandz7145]

Sparky gang

[@beautifulmind3028]

Good one

[@jdbrinton]

I remember first reading about this in a HAM radio magazine. It blew my mind. I wish it was taught as part of a more basic curriculum. Thanks for disseminating it to a large audience. It's such an important insight about the universe.

[@deviprasadmarudevagowda8517]

A simple but elegant way of explaining is most impressive to me and I hope more of these videos. Deviprasad

[@smitaaay]

I work as a trainer at a power plant. I was creating a training video for how the generator makes electricity and I was talking about the magnetic field created when we energize the rotor. I said to myself "Someone is going to ask why a magnetic field is created when current goes through the wire," which led me on a quest. haha Sir, NOBODY knows why it happens. Well, except you. haha I asked everyone out here and they were like "Uhhhhhh, I've never thought about it." And I was like "Me, neither, but I'd like to have an answer in case someone asks." I Googled it and found nothing. Your video popped up a few days later on KZbin and BAM, it's explained. So, thank you, very much, for taking the time to explain this. Just a fantastic job. 👍👍

[@Mau365PP]

Damn... I saw this first in Veritasium's channel, but seeing the proof with the equations is more satisfying

[@phenomenalphysics3548]

True that and solving more problems makes it more intuitive

[@LSATAngel]

Link?

[@seanmcmurphy4744]

I am an electronics engineer, and my 2nd year in college in honors physics we learned this. I was blown away! It was the single most fascinating thing I learned during my entire education.

[@tigersharma1443]

I still remember when i was in my 12th i asked the same question to my Physics Sir, in reply to that he shut me off saying that charge itself means electric field and moving charge itself means magnetic field, I think he meant that time that my question is useless as magnetic and electric field are very basic nature of charges, today i am feeling blessed after finding your channel accidently on KZbin, couldn't thank you more, although couldn't got along with the equation part but understood the theory of relativity involved here, A very big salute and huge respect to you for uploading this nice explanation ,Huge Love and Respect to you from India , Big fan of yours from today onwards, Subscribing and liking your channel videos is just a tiny token of appreciation which can never reflect the respect to you...

[@blacklyrics049]

indian teachers be like:

[@thomasauslander3757]

Teacher didn't know the answer to your question. ⁉️

[@sungodmoth]

We need more videos of this quality on KZbin

[@aaronchu0427]

Agreed.

[@alexandervonmalmborg365]

yes

[@baptistebauer99]

Wow!! I was mind blown by this!! I'm a physics student currently in College, and I never even imagined there was a connection there between electromagnetics and special relativity. You're awesome man. Great quality video right there. I wish I could subscribe twice to make you twice as excited...

[@stemcell7200]

Thank you! You could create another account :p. Often this phenomenon goes untaught - I first read about it in Purcell's Electricity and Magnetism

[@andrewcrawford2977]

Indeed, the original name of the paper that Einstein published when he moonlighted what is now called The Theory of Special Relativity was: On the Electrodynamics of Moving Bodies And it was this connection that made it famous. Not so much the implications about interstellar scheduling. Einstein had a lot of help writing this paper; from people who didn't necessarily agree (yet) about the implications about interstellar scheduling. In particular, Ernst Mach provided some insight about the equations regarding Doppler Shifting for the paper. And from this approach, you can get a much more intuitive sense of how a moving body observes different charge values than a relatively stationary body, regardless of the constancy of the speed of light. If you're familiar with Doppler Shifting, you know that an approaching siren sounds higher pitched, because the sound waves are relatively compressed. Now, rather than frequency of sound, as an analogy consider density of electrons. That is, the frequency at which an electron passes by an observer. Thus, a charge source moving relatively towards the observer is ""Doppler Shifted" to a frequency, that is to say charge density which is higher. And so with no knowledge at all of the spacetime topology implied by Special Relativity, it is clear that an current approaching closer to the observer has a relatively higher charge density than a current moving farther away from the observer The mathematics works out the same, since in this hypothetical thought experiment there is a chosen universal frame of reference. (The ground.). Indeed, the only situations where time dilation needs to be considered is in cases where General Relativity comes into practice, i.e. solutions to the Twin Paradox. Because in these situations alone, there is no longer that universal frame of reference. But that's another matter entirely.

[@vDarknessFalls]

@@andrewcrawford2977 Einstein has been proven wrong daily by the Thunderbolts project though. We know how magnets work today based on experiments you can do on home youself with a Ferrocell and a neodymium magnet.

[@seetharama7254]

Special Theory of Relativity is based on Logical Reasoning. Though the end results like time dilation, variation of mass etc. are as per predictions in my view there are some inaccuracies in the approach like unverified assumption of unidirectional speed of light as constant, unsatisfactory reasoning of Twins Paradox etc. I have worked-out a Physical Model years back. According to it the moving system undergoes Lorentz Contraction and the rays emanated from it at first focus of an imaginary ellipse will converge at a point at the second focus of that ellipse such that the observers eye-piece reaches there at same instant. I have worked-out Mathematical details of it. Seetharam [e-mail]

[@__shivam]

@@andrewcrawford2977 this made my day, thank you for the this intuitive explanation

[@WilliamSpaeth]

Thanks for such an informative video! In the derivation, (V+Vo)/C^2 should be (V+Vo)^2/C^2 for anyone else working through the algebra.

[@ohgosh5892]

Error correction is one of the most useful things in humanity. Never stop.

[@ohgosh5892]

humanity, and beyond!

[@deadvirgo]

I was keeping up intellectually until you busted out the equations. Now I need to go back to school.

[@davidwilkie9551]

Good idea, we all need to reiterate what we think we know, continuously.

[@Hari-888]

well, I guess you're stumpfed

[@KRYPTOS_K5]

Friend, equations are nothing in Physics. Concepts are all. That's the exact reason behind the terrible proximity between physics and philosophy. For example, using lorentz transform you easily perceive that c is the mathematical limit of velocity. However c is the physical velocity limit of WHAT? Well, c is the speed limit of any material point you would say to me (photons included) which are in the same inertial frame. For instance, if you shot different very accelerated protons in opposite directions they recede (going to their opposite "sides") almost two times the speed of light. Therefore the space itself doesn't obbey the lorentz transform!!! But empty space is a physical entity? Do you catch up what I am saying, friend? This is physics. Unfortunately in Physics you also need to be a very good mathematician (despite not outstanding bright) inside the field of physics. However math is not physics because physics is a study of concepts coupled with empirical observations. Brasil

[@flycrack]

@@KRYPTOS_K5 Your example isn't true under the perspective of special relativity.

[@HunsterMonter]

​@@KRYPTOS_K5 What? No, in physics the equations are king, and the concepts are just pretty stories to help us understand the equations. The key difference between the equations and the concepts is that the equations are falsifiable, if you plug in the same parameters as your experiment and you get a different answer, you know your model is wrong, whereas with concepts, you can only guess whether something is plausible

[@matthewpowers2735]

This video was incredible. I'm a new engineering student and this is something that I have ALWAYS wondered about. I knew they were connected, but I hated how I never had an answer as to WHY. I haven't encountered this in school yet but I will certainly be recommending this video to people. Maybe you could make one on why electromagnetic fields and magnetic fields propagate off of each other? I'm sure it is related to the fact that they are both electric fields, but I can't quite figure it out. Thanks!

[@jonathansevoro1845]

You've mentioned that every subscriber gets you excited, but seeing this video, and seeing it published this recently (meaning there is more to come), gets me excited. This video hits a special point I had been searching for for so long that explains a concept like this simply enough to be appreciated by someone without a PhD in the area but with enough education (say, undergraduate university) to understand and appreciate the formulae. Great work

[@igvc1876]

This was published in 1905

[@clavo3352]

You're a lucky guy Jonathan. Please get so knowledgeable about this that you obtain the understanding necessary to effect the medical and transportation and communication benefits it has to offer. This can work from the DNA level of molecular technology all the way out to Near Speed of Light travel; including atmospheric transportation. Also remember to enjoy life. Kiss some girls. It's related to this at a level that is of cosmic proportions.

[@-BarathKumarS]

@@clavo3352 cringe.

[@ohgosh5892]

@@igvc1876 yeah, youtube took a while to catch up! Great video in my view.

[@ohgosh5892]

We need folk with depth, but we also need folk with breadth, in education. Neither is individually sufficient. We must value all work equally.

[@mtewli]

At 15:28, in the last fraction should be squared nominator as well, not gust denominator. So right expression is: (1+{vv_0}/C^2)((1+{vv_0}/C^2)^2-(v+v_0)^2/C^2)^{-1/2}. The video is great, many thanks!

[@ohgosh5892]

correction is the best form of collaboration we have. Top post.

[@SK-ow4vw]

Hello! I would like to point out a very minor aspect that, in a way, has been overlooked in your video. Recently I did a similar calculation but instead I took a long single line of electrons and spaced them out so that 1 coulomb of them would stretch to roughly 1e8 metres. This means that for 1 ampere of current the electrons need to move at 1e8 per second. This is a good fraction of the speed of light, which is what I wanted because then I could work out the length contraction and not have to worry about the decimal accuracy. From this I calculated the perceived extra number of electrons per m. When I then use this result to calculate the force between two current carry wires. I get perfectly the result 2.00e-7 N/m as it should be. But there is a twist. If I keep increasing the spacing between the electrons so that the electron speed required for 1 ampere gets even closer to light the calculated force begins to increase beyond 2.00e-7 N/m. This means that in your equation there should be another Lorentz factor for describing situations with very large drift velocities. I presume that this must be contained within the definition of current in your equation. I initially wasn't sure about my result but then I found the following from Feynman's Lectures in Physics Vol II, chapter 13, page 13-9, where he derives the equation for the same force given as F = qpA(v/c)^2 --------------------------------- 2PIe0r sqrt(1- (v/c)^2) here p is the charge per unit volume. Feynman goes on to say. " Comparing this result for F' with our result for F we see that the magnitudes of the forces are almost identical from the two points of view. ...... We can say that for low velocities, at least, we understand that magnetism and electricity are just "two ways of looking at the same thing." I find it quite ironic that we use special relativity in one way to justify the magnetic force and then say it eventually deviates from this standard equation because of the effects of relativity. Please let me know if I've made some silly mistakes - one of them might be that the length that I initially started with actually is not correct because of the effects or relativity. Thanks!

[@prikarsartam]

This is a gem that you've put here! I'll try to work this out soon to find out if it's correct.

[@PrateekChauhan1995]

Excellent work !! What is this software??

[@crazydavidsmith]

Simply extraordinary and deeply moving. Thank you for sharing this Art. I watched it 3 times to follow the math.

[@barcode6495]

The best video I have seen in youtube. Wow relationship between special relativity and electromagnetism explained. Don't think all this physics happened by chance in the universe. More astonishing is the human brain. On the side, i saw a video of the James Web telescope and how it will open up in space with more than 300 activations. Then I saw a video of a baby in the womb of a mother and how it is just present alive there just to unfold when it is born. Talking about greatness

[@teddy05p]

4:49 Shouldn't the magnetic field around the fire be to the opposed direction by the right hand rule?

[@ZipDDragon]

I have never saw that proof before. Nicely done.

[@Vito_Tuxedo]

I have a vague memory of this from my sophomore E&M physics course in college, but your explanation is clearer. Thanks for this elegant derivation!

[@foroozanfaraji9842]

Wooow!!, I searched to compare Electrostatics and Magnetostatic so I could remember the magnetism formulas better because I never understood why the magnetic force has that equation. Now the puzzle is complete! Thanks a lot and good luck with the future videos

[@andrijauhari8566]

GORGEUSLY DONE, makes me more excited to take EM field II course this year

[@stemcell7200]

I'm glad I could pique your interest!

[@jimmyballer7047]

The best explanation of the relationship between magnetism and electricity I've seen. I noticed this video is now 4 years old. I'm sure in that time your priorities have changed, but if growing your channel is still a desire, put less stress on the math, and more stress on the principles. If I understand your video correctly, whether you're experiencing a magnetic, or an electric field, actually depends on your velocity (reference frame) relative to the field in question. If that is true, then the implications are pretty astounding. Most people can grasp that psychologically. However, fewer than 1 in 10,000 people can understand the math involved. Good luck, and thanks for your knowledge and hard work!

[@ohgosh5892]

We need a bridge between 'hard maths' and typical folk. Geometric representation of equations can help greatly, but it's not easy! My art work is appalling, I've tried doing this stuff, I typically get the words about right, but my drawings are rather childish. Still, it makes folk smile at my incompetence!

[@eltyo340]

Fantastic video, really, great job! You kind of lost me a bit when it came to explaining the frame of references but I think I got there in the end (I gave up on the formulas tho haha). I'd recommend using more visual elements to complement what you're talking about as you explain it verbally. Sometimes I have to pause the video, rewind and re-listen to what you said to digest it properly. I think like visually highlighting the frame of reference you're talking about would've gone a long way in helping my dumb face understand how it works. But yeah, I say do more visuals, the ones you already make are awesome! On another note, can I just say I really love your channel. Especially your enthusiasm for the things you're explaining and the way you do it I find really understandable. Also you have a soothing voice which doesn't hurt :p keep up the great work!

[@thomasmaughan4798]

There was an example, I think in Scientific American, some years ago. A train is moving, on this train near the engine is the escaping criminal, and a detective or policeman is on the train somewhat to the rear of it, and adjacent to the train is another policeman. At exactly the same instant, the two policemen, one moving with the train and one stationary beside the train, shoot lasers at the criminal. Do the lasers hit the criminal at the same time? Yes, presmably they do. The velocity of the train does not make the laser beam go any faster. Now if it was a bullet, then you would add the velocity of the train, to the velocity of the bullet, and it would get there before a bullet fired from the side of the train. But as you approach the speed of light, you cannot do it that way. And AT the speed of light, the velocity of the train becomes completely irrelevant; light goes at exactly one speed (in a vacuum) regardless of any velocity of its origin. It is this phenomenon that contributes to non-obvious behaviors in a wire.

[@complex_variation]

Hey, I love your video. I just stumbled on your channel. Just a recommendation, please, take out the background music I can't hear you very well with it.

[@davidt7317]

Absolutely fascinating. A number of things are now much clearer to me. Well done! I hope you will produce more material of this kind.

[@behrensf84]

oh wow! The fact that we can explain electromagnetism using special relativity with everyday velocities also shows just how much stronger the electromagnetic force is compared to gravity.

[@shubhamkumarjha6573]

Best video on this topic I have seen so far . Thanks a lot brother

[@aaronchristopher8472]

I think you are amazing. I didn't see a subscription link to subscribe to you. But I'll be looking for more of your videos. You dwell within the intuitiveness of math we've accumulated as math students. Then blend it well with the changes one can't intuitively see with the shortcomings of SR. Making it so simpler to comprehend. Thank you.

[@TooshanSrivastava]

such a well done video; to actually see the Math of it all work out to the same result in both frames of reference is profound!

[@imasiontist653]

Absolutely awesome. I got more explained to me than I bargained for from this vid.

[@CarrickCheevers]

Thank you, this is an amazing video. Kudos on your knowledge of these formulas and excellent hand writing!

[@christofferhansson7950]

Absolutely mindblowing! Your explanation of the concept was so easy to understand that even I could understand, with only an absolute beginner level understanding of electricity. Bravo!

[@zizimo3793]

I got here from veritasium too... its just AMAZING how these two forces are so deeply connected... and I would never imagine that the magnetic force formula comes from ELETROSTATIC concepts!!!! I have no words for thanking you, that was a masterpiece demonstration

[@paulfrindle7144]

This is fascinating because it shows that magnetism and electric charges are in fact a symptom of the time dilation of moving charged particles - as described by Einstein's special relativity.. Few people realise this. This is one of the best videos I've seen that describe this 🙂

[@premdeepkhatri1441]

Excellent video to understand Magnetic field generated by steady current (DC).

[@johnrutzen1861]

This is very interesting, thank you for presenting this and I liked your clear way of doing it. I love explanation as to what is actually taking place. So here's a question, why are magnetic fields in lines?

[@Greg_Chase]

It is known that a magnetic field around a permanent magnet is caused by the alignment of 'magnetic domains' which said in a clearer, more physically precise way means the alignment of electron spins. Electron spins normally are randomly aligned and no magnetic field occurs. When electron spins are aligned (in iron or cobalt or nickel permanent magnets), a magnetic field manifests. It is known that the speed of electrons in a current-carrying wire is NOTHING like the analogy of 'flowing water in a pipe' - the "drift current" velocity of electrons is astonishingly slow. Look at the 'drift velocity' page on wikipedia. Given these two facts, it is reasonable to say that electron spins are aligned in the wire and that is why a magnetic field is created around the wire, when a battery or power supply is attached to the wire. The application of a power source across the wire aligns electron spins. The 'drift velocity' of electrons in a wire is about 23 microns per second (that's a distance of 0.000002 meters per second). That's for a wire carrying 1 amp of electric current with a wire diameter of 2mm. . .

[@isaacjohnson8752]

I’m trying to visualize this, but I’m having one struggle with this idea. It is the electric field that is applying the force on the charge carriers, and electric charges need not come in dipoles like magnetic fields. The property known as spin is associated with the magnetic field, and electrons will align with magnetic fields in one orientation or the opposite (as evidenced by the Stern Gerlach experiment, to name one), but I have never heard of electrons orienting their spins in the same direction in the presence of an electric field alone. So my question is, if a magnetic field is required to align magnetic domains (assuming the material isn’t ferromagnetic, like the average current carrying wire made of copper isn’t ferromagnetic) then what would cause the alignment of domains that would produce the magnetic field about a wire. In other words, you can’t cause alignment, in say copper, without a magnetic field. So claiming aligning domains create a magnetic field doesn’t make sense with my knowledge that a magnetic field is required to align these domains. The electric field does apply a force on charged particles, but the charged particles in the wire aren’t electric dipoles, and spin is not affected by the electric field as far as I can tell. Without a doubt I’m more than interested in any information you have that would help me understand the model you are describing, I’m perfectly happy to be wrong and learn something new. From what I can tell the relativistic effects show a direct and accurate prediction of the origin of the magnetic field about a wire. Even though drift velocity is very slow the change in apparent electric charge density in the wire due to length contraction does predict the magnetic force is simply and electric force in disguise. This was what special relativity was originally about, and why it was invented. I am currently in my third semester of EM, and we are currently studying relativistic effects for electric and magnetic fields. While I wouldn’t claim to be any sort of expert in the field (I do really well with the classical EM, but definitely need more study in relativity), it seems like this videos explanation is the most well respected and calculable theory.

[@Greg_Chase]

@@isaacjohnson8752 The simplest atom (hydrogen) is nothing more than a dipole. Proton nucleus (positive charge that has a magnetic moment) and electron (negative charge that also has a magnetic moment). I understand your point. But there is no getting around the magnetic field that manifests around a wire when a charge separation (aka electric field) on the ends of the wire is applied. The charge separation that is polarizing the constituents of the wire is supplied by a battery or a power supply. There is also no getting around the fact that in order for a magnetic field to manifest, aligned electron spins are required. If you want to propose a new physical mechanism that would allow a magnetic field around the wire - or anywhere, really - to become manifest, with completely randomly-aligned electron spins, I want to hear that. An analogy: the physical existence of paint is required to paint a fence. If you have a brush, and the fence, and an empty paint can, the fence will remain unpainted. You cannot paint the fence without paint. You cannot manifest a magnetic field without aligned electron spins.

[@Greg_Chase]

@@isaacjohnson8752 Another issue SR/GR did not account for is the possibility of electric and magnetic field carriers in the Vacuum. Remember - all magnetic field-generating entities - wire with current, a permanent magnet - function in space. The QED Vacuum is said to consist of electron-positron pairs that quickly self-annihilate. Our working theory relies on the fact that electron-positron pair annihilation produces gamma rays - this has been demonstrated in labs across the globe for decades. Yet there is no gamma ray background that is detectable in space (or anywhere) that should exist, if the QED Vacuum actually consisted of rapidly-annihilated electron-positron pairs. We work on artificial gravity devices and rely on the persistence of electron-positron pairs throughout the Vacuum for our work. In General Relativity, Einstein said "space is empty, there is no aether" and also said "space is curved". If there is nothing in space, there is nothing to curve. This is a problem. In Einstein's defense, Dirac and the existence of electron-positron pairs came many years after GR. When a propagating electric and magnetic field leave our Sun (a light wave for e.g.) - when electromagnetic waves have left our Sun, but have not yet reached Earth, they are in the Vacuum. In order to manifest the electric field and the magnetic field in the Vacuum, there must be electrically and magnetically polarizable constituents in the Vacuum. You will NOT find 'Vacuum Engineering' taught in the university - artificial gravity tech has been perfected and sequestered for many decades.

[@douglasstrother6584]

I first came across a similar derivation in "Electromagnetic Fields and Waves" by Paul Lorrain & Dale R. Corson as an Undergrad.

[@douglasstrother6584]

www.amazon.com/Electromagnetic-fields-waves-Paul-Lorrain/dp/0716703319

[@MrPaulhunter]

Thank you for your explanation. I’ve saved it in my favorites file!!! I look forward to seeing more of your videos.

[@earag31415]

I had seen this topic on veritasium a long time ago but i really really appreciate your breakdown and approach. I was also surprised to learn special relativity was behind all of this

[@thomasmaughan4798]

"I had seen this topic on veritasium a long time ago" I have a feeling that Veritasium is wrong about some aspects of this. He dismisses the importance of the wire and the electrons contained in it.

[@earag31415]

@@thomasmaughan4798 maybe you should make your own video so I can know what you mean because you’re giving me no info here. I think the main idea is how length contraption is a main cause of the phenomenon.

[@thomasmaughan4798]

@@earag31415 "I think the main idea is how length contraption is a main cause of the phenomenon." So it seems. But whether it is a cause or a consequence of what is actually happening (or both together) is unclear. At time zero, everything is not moving and there is no charge. There is also no cat to rub on amber. So you must introduce charges or holes (protons that want electrons) to one end of the wire. WHY then will anything move? Obviously it is the presence of an electrostatic field; not yet magnetic since nothing is moving. But the electrostatic charge of the battery, for instance, on contact (or an instant before contact) repels the electrons in the wire nearest the battery. They repel the next, and the next, and so on. This creates movement, movement creates magnetism, and magnetism further moves electrons.

[@earag31415]

@@thomasmaughan4798 yesss I absolutely agree. I will not go back and check whether he mentioned that or not but I do agree and believe that there it a time of sole electrostatic which then evolves into electromotive force.

[@yutokas]

¡Congratulations! I followed your reasoning and you clearly convinced me that from the Special Relativity point of view, there is no magnetic field caused by an electric current. And much more: you made me feel the beauty of this comparison between the non- relativistic and relativistic models. A question: Is there a similar description of the interaction between the wire and a permanent magnet?

[@photogenicx5788]

Wonderfully explained. Thanks for solving the riddle of my mind.

[@philperfect8800]

Hello, Thank you for this magnificent presentation of magnetism seen through relativity. I think I have it all figured out, but there is one thing that surprises me. The video shows that the magnetic force is in fact due to an electric field created due to the difference in electron/proton concentration in the wire, a difference due to relativistic effects. However at 11:18, you say that, apart from any movement of any external particle, the electron concentration is already higher due to the intensity of the current flowing in the wire: the distance between electrons is reduced ( gamma(V0)) due to the movement of electrons. This should therefore create a global charge in the wire, generating an electric field! This does not appear to be the case in reality. Or am I making a mistake?

[@tonyduncan9852]

Yes. You have to be _moving with_ the charged particle to experience the electrostatic charge effect of the wire. In reality!

[@Merilix2]

"should therefore create a global charge in the wire". Not from our perspective. In the rest frame of the wires they are still (almost) neutral. Except fields created by charge separation at the terminals of resistors of course. There are no Electrons / Protons appearing from nowhere.

[@anthonyskilton8634]

Very good, thank you and I'll look forward to seeing anything you may cover on Maxwell 's Equations and possibly Quantum Mechanics? .....please! !

[@TumulKhan]

One question still rises. If the charge outside the wire stays still. It'll still see more negative charges in the wire than positive charges. So it should feel a force. But we know, it won't feel any force in static condition. Can you explain please?

[@maalls]

yes please someone explain this

[@neoruss3553]

As i understood even though moving electrons appear contracted to the stationary charge outside, distance between their middlepoints is still the same as distance between two positive ions that don't move. Because of that there is no difference in charge density between electrons and ions in wire, there are same number of electrons over distance as ions no matter if electrons are contracted or not. Don't take this seriously this is just my understanding, i didn't read it anywhere. I am happy to hear someone who really know this stuff and can explain it correctly and with proof.

[@bengineer_the]

I listen to this repeatedly, to remind myself. Brilliant

[@DaveJ6515]

This is the best way to guide students to understanding special relativity: I started asking if the "v" in Lorentz force didn't look fishy .... "v" with respect to what? And so on. This is well explained (of course) by Richard Feynman in his wonderful Lessons.

[@KennethKamhw]

So far the best of a kind i have ever seen

[@anthonypape6862]

This would be a good title if you conveyed this information in the early 1800s. I wouldn’t call it “hidden” from anyone that has yet to take high-school physics. One question how on Earth can you say Oersted discovered the link between electricity and magnetism when it was Faraday who did so with a compass. Which implanted the idea which unfolded the whole principle that we know and understand today. You could make a case for Joseph Henry who seemed to be doing what Faraday was in the US at the exact same time but Henry didn’t get credit and it is widely credited to Faraday.

[@Spiritman597]

That was a totally awesome video that you produced although I must admit I didn't understand half of it I sure would like to take a course so that I can understand the complexities of all the mathematics equations in the video. Can't wait to see what you produce next thanks

[@gassonteddy4293]

Great stuff brother. I want to learn more of this.👍

[@ManyHeavens42]

Magnetic fields allow us to move through many Dimensions. Remember: Time is equal to distance, join the singularity.And its Not Robots. You have a Voice Here.

[@shinwushu]

That was absolutely stunning. Thank you so much for putting this together.

[@pboston6RR]

Great video. It has gotten my 83 year old mind thinking of the explanation for the apparent reflection of data sent along a copper wire to an unterminated end. I’ve seen the results of the addition of the originating and reflected wave forms producing locations along the wire where there is a null signal. I’ve seen a computer sitting next to a printer not be able to see the printer until a terminating resistor is placed in the line, but other computers have no problem seeing the printer. I knew how to fix the problem but wasn’t able to account for the phenomena physically. Anyway, thanks for sharing.

[@owlredshift]

Be well, Paul. When and if I should make it to your ripe age, I should hope that I will keep my facilities' gears and cogs spinning like you are. Keeps the cobwebs and rust from forming. Where folks used to worry about aging, being alone, or only having regularly scheduled programming/books and a newspaper to read all day for entertainment, now we span the entire globe instantly -and without thinking -ready to meet any other like minded people we care to, to share ideas or as a catalyst for relationships. We are lucky to live in this time of humanity; where data may flow as fast as one can operate the spigots! 🚰🙌

[@subramaniantr2091]

awesome. thank you. what tool do you use to do this editing and even select portions, scale and shift them.. Could you extend this to explain back emf and as to why V = dphi/dt? It would be really really great to be seeing inductors and transformers and imagining their principles in terms of electric fields.

[@timvw01]

Great video, especially adding the historical context. What about permanent magnets?

[@anthonypape6862]

Permanent magnets in nature are not very strong. We make super strong ones by running current through certain metals in which all the atoms domains (the atoms electrons spend more time on one side of the atom) line up perfectly and you have exactly half of the metal with a north or positive charge and half with a south or negative charge. How does a magnet repel or attract another magnet. By what mechanism is going on? We don’t know. We only know the rules of the game. Like poles repel, opposites attract. Like the atom itself we do not know how the proton repels other protons but attracts electrons. We just know they do. Also we don’t know what the hell gravity is. All stuff I took for granted. We just know the rules and when you know the rules you can do a lot with it.

[@sangwookim5551]

13:30 wait so in summary moving charges do not actually produce magnetic fields but rather it gives the illusion that it does? Since moving charges attract/repel other charged particles...but wait, doesnt the fact that moving charges get attracted/repelled by the moving charges( wire) a proof of the Electric Field around the wire and not Magnetic Field? How would a stationary observer looking at the particles being attracted to the moving charges think that the attraction is due to Magnetic Field? Dont you need interaction with magnetic dipoles instead? Could someone please explain this??

[@asdfniofanuiafabuiohui3977]

when you have an electron moving at the same speed as the electrons in the wire, the electrons in the wire expereince 0 length contraction from the perspective of the moving electron outside the wire. What does get contracted is the (distance between) the positive protons which creates a net positive charge in the wire from the perspective of the moving electron, which then gets attracted to the wire. However, the electrons in the wire are moving against the direction of motion which means their velocity is even greater leading to much higher charge density, thus in this situation electrons are repelled and protons are attracted

[@DrDeuteron]

@@asdfniofanuiafabuiohui3977 that's not correct. The Cu spacing and electron spacing are both "d" in the wire's rest frame. So if you move at "v" which is equal to the electrons, then the proton spacing is contracted to d/g while the electrons are dilated to gd. The charge density is then goes as +1/(d/g) + -1/(dg) = (g-1/g)/d = (g(v/c)^2)/d, which matches the transform from a perpendicular magnetic field into an electric field.

[@asdfniofanuiafabuiohui3977]

@@DrDeuteron the electrons in the wire, If you move alongside them, do not experience length contraction relative to you. When they were moving they did experience length contraction, which yes means that they're expanded from a stationary perspective. The base spacing isn't not length contracted because they're already moving, they're not going from 0 to -1, they're going from 1 to 0.

[@georgescriven1108]

Amazing video, great that you don’t shy away from the algebra!

[@Dogmatix314]

Thank you for the clear and compact explanation. It’s really neat how one can explain the magnetic field by looking only at the electric field and relativity. By using different frame of reference, one can also explain the electric field as a magnetic field of charged particles that move through time at the speed of light. I wonder which explanation is more fundamental in explaining the electromagnetic fields?

[@Merilix2]

In my opinion, the electric field seems to be the fundamental one because there are charges as source whereas magnetic fields are source-free fields. Magnetic forces are created by moving electric charges, magnetic forces are detected by their influence to electric charges... right? Another issue I have with magnetic force is their math derivation using cross product. The right-hand-rule is just by convention where asking for a vector perpendicular to two others has indeed two valid solutions. I think this ambiguity can only be resolved if it is applied twice so that the convention rule cancels itself.

[@wthomas5697]

Very impressive! A youtube video that actually does blow one's mind! Well done!

[@a.gabbey5569]

This video on the connection between electromagnetism and special relativity gives me an inclination that this was a similar way in which gravitational field and special relativity were also connected to give rise to the whole gravity is the curvature of space-time produce by a mass.

[@vincenthughes5795]

Many other authors of similar videos claim that a stationary electron would not experience any electric field from the wire with current, because somehow the wire stays neutral. From this video I understand you are saying that from the stationary frame of reference, the wire with current is indeed negative?

[@carlosserrano4048]

Thank you for that insightful through line.

[@bchain6416]

Nice, so if I understand correctly, this explains that the magnetic field caused by moving charges is in fact an electric field caused by relativistic effect. But what about static magnetism caused by a permanent magnet, has this also in some way a connection to an electric field?

[@mmoonchild276]

watch Science Asylum's video on this topic

[@nmarbletoe8210]

I think we really want to think of an "electromagnetic" field and not one vs the other. A permanent magnet has moving electrons in the metal :)

[@lancearmada]

We didnt talk about special relativity in my undergrad program but i could kind of follow and this really illuminates the topic (and also validates my confusion i guess…)

[@neoruss3553]

So i have seen many videos about this concept and all of them ignore what happens when outside charge is stationary/has no velocity just like ion in wire. In this frame of reference moving electrons still contract but i guess even though they contract distance between their middle points stays the same which is also equal to distance between middle points of ions. This means charge density should remain equal even though electrons can appear contracted??

[@mowtown75]

It moved too quickly for me, but I can rewatch, pause and think. Don't you go slowing down :) I still got the gist of it, and was educated further on my journey of understanding whether electrons moving in the wire deliver the power or whether its the sum/compliment of the EM field and the wire. Some assert that the wire is not the vessel of the power, but the director (my words) that the EMF around it follows to deliver power at the circuit load. I am enjoying the research and enjoyed your video thanks. Tim

[@abdellahkharicha8776]

Many thanks Can you show (demonstrate) it in a vectorial form ? Can we show that this emerging electric field is indeed E=UxB ?

[@vithursonsubasharan5030]

One of best thing i have ever seen in my life

[@JohnDlugosz]

2:00 So is that way positive charged atoms are called CAT ions?

[@yellowbacon69]

Clever

[@amitsachdeva1393]

What are the pre-requisites of understanding the derivations? Overall dude it's a great video . It's just prompted me to know more about this . Thank you really!

[@DrDeuteron]

Undergraduate electrostatics and magneto-statics will explain the E and B fields of lines of charge and linear currents, respectively. (it's late 19th C physics). The length contraction / Lorentz transformation is 1st semester undergrad special relativity. (It's early 20th C physics, 1905 to be exact).

[@santoshpanth6343]

P

[@bharatyonzen307]

Thank you for brushing on my rusted fundamentals on electromagnetism !

[@Bao_Lei]

Amazing! Can magnetic field from magnets and magnetic force be explained in terms of electric field and charge movement too?

[@francescosacco4969]

Wonderful! Please, keep going with this channel!

[@andrjsjan4231]

4:50 well that doesn’t have to do anything with the magnet ic field the deflection of the electrons right? It has to do with the attraction of the charges right??

[@DrDeuteron]

no, the cause is not a Lorentz invariant thing. Some frames say electricity, others say magnetism, most say "both".

[@jimhall3810]

The music is very distracting. The video is awesome

[@2011vortex]

Just subscribed! more physics videos please. Would love to know equations for the motions of planets with sample problems. Again nice vid.

[@Robleh100]

This is a precise and somewhat concise explanation of the relativistic effects of electric current flow in a wire. One small criticism I have is this. Don't you think it would be better if you chose V1 and V0 in the multiplicative term, thereby avoiding the appearance of W in the term? It threw me for a brief second until I paid attention and saw what the term represented and not another variable.

[@marcomikemarco]

something does not sound right. at 11:26, electrons moving in the wire are closer together than when they were stationary.... so the stationary distance is calculated as d°*gamma(v), which is larger than d°. but protons, when stationary, are at distance d°. so it looks like we are saying that in stationary conditions protons and electrons are at different distances and so when stationary the wire is not neutral.

[@MrNibiru2112]

Wow, this is great, I couldnt resist your request for subscription...from tanzania;;congrats...

[@andrewpicciochi1269]

Non Physics students would like to understand. Please Explain the video in a way that presents the concepts with out the math. I was completely lost when it comes to the math. Maybe another video with a link below. Thanks for the presentation.

[@ugljesapopovic9392]

So one question pops to my mind though. If charge is stationary and we stay in our frame of reference... Positive protons in wire are also stationary but the electrons are moving with speed Vo therefore we see that distance d0 shortens by the factor of 1/y(v0) right ? And we have a slightly negatively charged wire. Shouldn't stationary charges also be repeled/attracted from/to wire due to this electric field (and we don't have to look at that formula F=qvB)?

[@SK-ow4vw]

This is a very good question. I have been puzzling about this too. If you treat the positive charges as stationary having initially the same spacing as the free electrons then indeed it would seem that a stationary lone electron would be repelled from any current-carrying wire. It is only if the lone electron moves at exactly half of the drift velocity then it would not feel any force. The drift velocity for 1 ampere in a normal copper wire is of the order of 0.02 mm per second only. Any speed for the lone electron beyond half of the drift velocity IN THE DIRECTION OF ELECTRON DRIFT IN THE WIRE will attract the electron towards the wire. Any positive velocity less than half of the drift velocity (and all negative velocities) would repel the lone electron. So it seems that there is a very slight asymmetry in this. I haven't heard this mentioned in any textbook. But I cannot find a reason for rejecting it - maybe someone else can help here. A great question!

[@gratefulamateur1393]

This elegantly describes how you need the guy with the funny hair to really explain how radio waves are produced. It always seemed to me that folks just waved their hands when they showed how EM waves are created. This really proves it! Absolutely brilliant.

[@quandarkumtanglehairs4743]

kinks in the Field from accelerating particles in a radiative pattern, a sinusoid

[@keylanoslokj1806]

The fuzzy hair guy didn't discover shit

[@thomasmaughan4798]

I've been working in radio and electronics for many decades but this comes closest to explaining why current flows in a wire in the first place. When you connect a wire from the positive side of a battery to the negative side of the battery, how exactly does anything know this event took place? Evidently, the negative side of the battery immediately pushes against the immediately adjacent electrons in the wire regardless of whether the other end is connected to anything at all; it is the electrostatic repulsion. Same with the positive end but pulling electrons. This instantaneous force is electrostatic but becomes magnetic as the actual movement takes place and electrons shuffle. Electrons move slowly but the shuffling takes place at nearly the speed of light; that is to say, how quickly do adjacent electrons feel the force impinging upon them. What is unique to this understanding is relativity; that this movement effectively changes charge density and apparently makes the force stronger than one might suppose. While the current is increasing (as from a short circuit), a magnetic field will be building and as it builds will induce a counter-force (counter emf) that tends to resist further increase in current. But once the current reaches some equilibrium, so will the magnetic field, and at that point you will have magnetism but since it is neither growing nor shrinking, also will no longer resist the change in current. I'm still a bit fuzzy on some of this so I expect to replay this a few times to fullly grasp the principles.

[@DeadCatX2]

Don't forget about the displacement current that begins to flow when the electric field capacitively couples to the load through a transmission line (the capacitance looks like a short to the changing voltage as the wavefront propagates down the wire). Then, as you described, once the line has reached electrostatic equilibrium the displacement current will cease and the inductance of the transmission line will keep the direct current flowing (the inductance looks like a short once the transmission line has reached equilibrium). This is also why "ELI the ICE man" - the Voltage (E) in the inductor (L) leads the current (I), hence ELI; and conversely, the current (I) in the capacitor (C) leads the Voltage (E), hence ICE.

[@gmotionedc5412]

Given more time I could have understood this! Good job!

[@ohgosh5892]

🙂

[@jasonrc3667]

What about regarding PEMF and TDCS? As regards to Neurological issues

[@connerd5647]

So say you're viewing a current carrying wire in a stationary reference frame, do electrons moving relative to the observer experience length contraction too? If so why isn't there an overabundance of negative charge observed in the wire from a stationary reference frame that can act on stationary charged particles?

[@shubhamsingh3519]

Your exact doubt is explained in this video kzbin.info/www/bejne/omempHaNgrdsjMk You can Forward to 5:35

[@JustNow42]

Connection between mag field and electric field is that the magnetic field's energy is the kinetic energy of the electric field.

[@ambrosiolerma5295]

If it is possible, is there any kind of exploration of how the movement inside the earth causes an electromagnetic force around the earth. Thanks

[@binra3788]

Why persist such an idea? While iron in the core can be magnetised or magnify an electrically produced field, heating demagnetises. The obvious is that there is an electrical potential between the solar plasmasphere in which Earth nests, and the Earth, such as to operate an electrical circuit with a proportional response to its environment. Beliefs set deep in scientist's thinking become foundations for modelling that becomes 'too big to fail' in human economic, social and political terms, and so we stand on the shoulders of giant mistakes. Math based fudge can always be used to extend models as a means to save appearances, but at cost of increasing banal bafflement in the face of empiric data that is thus increasing walled out by the politicising of 'The science' as distinct from honest open enquiry'. Material universe is electrically driven and informed. In broad terms the 'electric universe' idea is particularly instigated by the discovery of plasma physics. I offer this only to curiosity.

[@jevertt]

Great video! But, there are two things I don't really understand (I'd be super grateful if you could help me understand)... 1. When a charged particle is stationary and there is a current in the wire, wouldn't the electrons flowing in the wire be length expanded from the particles POV? And if that is the case, wouldn't a stationary charge experience an electric field? This isn't what we observe, though, right - we only observe what we call a magnetic field that causes zero force when the particle is stationary? 2. From the POV of a moving particle, you have length contraction of stationary particles, so a charge density change. This is where I have trouble - normally I see visualization of objects moving getting stretches or compressed, but the space between objects isn't effected. It seems like what really matters here is that the distance between the particles is contracted, not so much the particles themselves (since charge is conserved in special relativity). Maybe this has to do with the probability wave or something, that they aren't really particles?

[@tonyduncan9852]

You just cleared out a blank spot in my understanding of magnetics. Thanks very much! However, it is a pity I am seventy-nine years old and about to kick the bucket, so to speak.

[@thisflyingpotato4227]

You deserve more subscribers and you just got one more !

[@leonidkerchev4256]

Pleasure to watch!

[@rer9287]

when you say "who would have thought special relativity would provide the answer?" - it would have to be someone who hasn't read Einstein's original paper that is now the foundation for special relativity. In that paper, the title and opening paragraph outlines this exact issue.

[@ripwords]

I found this video due to the confusion i had on Veritasium’s video on the same topic. In the video he stated that when the outside charge is stationary there would be no force on the charge even when there’s a current. And in your video you stated that since the electrons Are moving the distance would be smaller than they’d be if they are stationary, then why won’t a force be exerted on the outside charge if the electrons density is higher when the outside charge is stationary

[@mrinaldas8731]

Exactly. I have the same doubt

[@standlegweak9854]

@RipWords I had the same question in the back of my mind. The Veritasium explanation was the first time I had seen someone frame it using SR. But now it seems incomplete.

[@GiraelCS]

Yes, the expression for the contracted length between electrons in this model is logically inconsistent with the rest of it. If no current is flowing through the wire, then the net charge density must be zero (it is quasineutral), therefore the lengths between electrons and cations must be equal (for all observers). Once the electrons start to move they "enter" a non-rest reference frame relative to the wire (cation lattice) with the drift velocity v0 and the observer in the rest frame of the wire must therefore observe contraction in their distance, therefore difference in charge distributions (densities) of electrons and cations, therefore a net electric field as well. That would make even a non moving charge accelerate. That is, if the principles of STR are actually at play and are such as discribed in this and Veritasium's video.

[@GiraelCS]

Also, the main counterargument still lies in the nature of the force applied. Electric field always accelerates IN the direction of its intensity, whereas the magnetic field accelerates PERPENDICULAR to its intensity as well as the charge's velocity. Just based on that this model can never hold, because this kind of electric field can never produce the circling trajectory the charge would actually move along.

[@joao_ssouza]

@@GiraelCS It seems like the magnetic field is defined in such a way that its effects are the same of an eletric field. About the non-moving particle being accelerated, if you come to know how to explain that I would appreciate. I have this same question and can't find the answer anywhere.

[@semplar2007]

Watching Veritasium talking about the same, was like "Meh, well, idea is good, but maybe he's right, maybe he's wrong, there's no proof, who knows". Watching your video, especially when you derived formula for magnetism from electrostatics plus relativity was like "now we're talking". Well done man! Instant like and subscribe!

[@frsvegetaop2483]

I think u should watch his video carefully again Bcuz i found that video helpful too, it wasn't right or wrong, he explainded this phenomenon simply

[@sreekumargopakumar10]

Wow - I thought i went to school for Electrical Eng and I knew this stuff - still remember the puzzle as to how two wires attracted when current flows in opp directions, when I first encountered mag field between moving currents - just the curiosity faded away with rigor ~~ never thought it as sp relativity.