maxwellsequations #speedoflight #electromagnetism Why is the speed of light what it is? Maxwell equations visualized

#maxwellsequations #speedoflight #electromagnetism Why is the speed of light what it is? Maxwell equations visualized 1,728,833 viewsPremiered Mar 25, 2020 Arvin Ash 719K subscribers Twitter: @arvin_ash The History Guy video on Maxwell: https://youtu.be/NuWEqE4k230 . Why is the maximum speed of the universe the speed of light? Maxwell’s equations explained and visualized. Why is light so fast? What is light made of? Almost all modern technology is based on Maxwell’s equations. Not only do they describe every electrical and magnetic phenomenon, but hidden within these equations is a fundamental truth about the nature of light, and why it is the ultimate speed of the universe. We are going to visualize the equations with graphics. Objects have something called a charge. This is a property of matter like mass is a property of matter. If you have a static object with a charge, it will affect only other charges. And if you have a static magnet, it will affect only other magnets. But if you have a moving charge, it will affect a magnet. And if you have a moving magnet, it will affect a charge. That's what the four equations are telling us. A charge is the source of an electric field. If I have another charge, you can understand exactly what force it will feel. The first equation is a formula that tells us how electrical charges create electrical fields. It is based on concepts developed by Carl Friedrich Gauss. Permittivity of free space is required in the equation. It is the resistance of free space against the formation of electric fields. The second equation is called Gauss’s law for magnetism. It says that if you had the same sphere but it was a magnet, you will never find a configuration where the magnetic lines of force always point outward, or always point inwards. In other words, a magnet will always have two poles. There are no magnetic monopoles. The third equation is called faraday’s law. This law says that if move a magnet, you will create an electric field. This equation tells engineers how to generate electricity from a generator. The fourth equation is Ampere’s law. It says that if you have moving charge through a wire, or an electrical current, you generate a magnetic field. This requires a constant of nature called mu naught. This is the permeability of free space. This is the ability of free space to allow magnetic lines of force to go through it. Note that there are two terms in this equation, one term tells you the moving electrical charges can create magnetic fields, and the second term tells you that moving electrical fields can also create magnetic fields. This idea of magnetic fields being created from electric fields was Maxwell’s addition to Ampere’s law. #maxwellsequations #speedoflight #electromagnetism Both of these constants have to be measured, since they are inherent properties of nature. They are not derived from anything. What does this have to do with light? If I take an electric charge and put it on a pole, and I just move it up and down, what will this cause? According to ampere’s law, if an electric field moves or changes with time, it would create a magnetic field perpendicular to that. And because of the changing movement, the magnetic field would also be changing with time. And according to Faraday’s law the moving magnetic field lines would create another new set of electric field lines. Now, since the same thing is happening to these new electric field lines, that is, they are changing over time, they would in turn create new magnetic field lines. And the new moving magnetic field lines would create yet more electric field lines. You have just created a self propagating wave. What is the speed of this wave? You find this using advanced multivariable calculus which Maxwell was very good at. He comes up with is 1/V^2 = epsilon naught * Mu naught. Solving you get Velocity = Sq root (1/epsilon naught * Mu naught). So what the equations are saying is the velocity of this wave is inversely proportional the permittivity and permeability of free space. It makes sense that the velocity of any wave would be inversely proportional to the resistance of the substance it is traveling in. You might ask, well why are mu naught and epsilon naught those exact values? No one knows why. These are just the constants of nature. Now we take the measured values of these two constants, and do some simple math. The speed of the wave is about 300,000 km per second. Maxwell realized that light must be an electromagnetic wave. About 40 years later another great scientist by the name of Einstein did his own thought experiments inspired by Maxwell’s equation. And his thought experiment was based on one simple assumption. He asked if the speed of light is an inherent property of space, why would this speed be any different based on the speed of the observer? And it was from this simple assumption, that he came up with the special theory of relativity in 1905 which changed our ideas about the nature of time. Chapters 3,961 Comments rongmaw lin Add a comment... Arvin Ash Pinned by Arvin Ash Arvin Ash 2 years ago (edited) For those of you wanting to know exactly how Maxwell derived velocity using multivariable calculus, here is a paper that shows the details of that derivation: http://srjcstaff.santarosa.edu/~lwillia2/42/WaveEquationDerivation.pdf . Also, this video may be helpful, https://www.youtube.com/watch?v=7hMPTdppBdA In addition, several people have expressed that the prism graphic is incorrect because the direction of the exiting light is pointing up rather than down. Take a closer look at the sequence of colors. This graphic is not exactly incorrect. It is simply an upside down prism. You may object to the light seeming to bend upwards, but this is just a matter of perspective. I took artistic liberty in that, I admit. Red would deviate more than violet. But yes, the rays would point downward. (EDIT: New more "accurate" thumbnail was added later) 220 Arvin Ash · Richard Masters Richard Masters 2 years ago I teach electrical theory at university and I’ve never seen such a brilliantly clear explanation of the Maxwell equations and their consequences - Many Thanks. 1.2K Arvin Ash Edward Ray Edward Ray 8 months ago wow, as a physics enthusiast, I’ve been looking for this level of understanding of “c” and how it can be derived for years, and this video nails it. Thank you, Arvin Ash!!! 59 Irina Monich Irina Monich 3 months ago Just imagine how Maxwell felt when he realized that he arrived at the speed of light... What epiphany! I wouldn't be able to take another breath from excitement. This is a great video. Thank you. Amazing to see that the speed of light can be derived from those two constants -- vacuum permittivity and permeability of free space. It actually makes sense. 7 Sanker PG Sanker PG 1 year ago Great job Arvin. If only all educators could explain as you do; lucid but without losing the profoundness of the idea, the world of learning would be a much more interesting place. 1 Tom Heinle Tom Heinle 9 months ago Just imagine the thrill that Maxwell must have felt in that moment when the two speed limits matched. 23 WWTormentor WWTormentor 1 year ago Imagine if we could go back in time and show these great minds the technology that their great works led to. I wonder what they would say about it. 103 Esdev Esdev 2 years ago I've learned more about electromagnetism and the meaning behind Maxwell's equations in these 13 minutes than in 5 years of studying electrical engineering. 332 Arvin Ash Adrian Nuske Adrian Nuske 1 month ago this explanation tops every other one by a light-year-leap! You delivered knowledge without the "diva-blind" down. As simple as it truly is. Most deserved follow and like ever given! thank you! 1 redlights9991 redlights9991 11 months ago Unlike most of the people commenting here, I’m not an engineer or have any connection with engineering, in fact I teach marketing at a university. So I have no background in engineering whatsoever, but the way you have explained this, even a layman like me understood it so well. You are a great teacher! 1 Mohammad Ali Mohammad Ali 1 month ago (edited) History and Physics combined. I also learned from this video, so it is literally educational too as well. Nice video and a huge thank you for this video. I also forgot to mention that there was a project that was done in school regarding electromagnetism. I did recognize how with electricity, a magnet could also be made too, but nothing more than this video had taught me clear enough than just a book about it. Yet this was one of the many reasons why I watch this video. It’s not just Biology that drew my attention nowadays since I met a doctor regarding electrical pulses throughout the body and brain. It is Physics too, especially because electrical engineering grabbed my attention for a major. Not that I say I am going to choose neither or both though. 1 Sonu Singh Sonu Singh 8 months ago I woke up feeling big and then I watched this and now I feel super super small and can’t fathom with how intelligent these guys were. Great video as always Arvin. 2 Mehmet Terzi Mehmet Terzi 1 year ago Arvin, the world needs you and more people like you to help us make sense of things. I love watching your videos. Thank you 1 Joe Anarumo Joe Anarumo 2 years ago As a former undergrad in physics and grad in oceanography, I wish all educators were required to be at this level of understanding, enthusiasm and preparedness. Its nice to see you to explain serious material so simply, as well as capture the attention of thousands of people in subject matter deemed widely as boring and drab. Thank you for doing this, I'm subscribing to your channel. 205 Arvin Ash Bruce kemp Bruce kemp 10 months ago This video is interesting. There are some parts that get a bit technical, but overall the explanations are quite good. Perhaps there could be another version for those who have some background in Calculus. Some parts of this video explain why (and how) Calculus relates to everyday life. Some students would find this item interesting. 1 Richard Rigling Richard Rigling 1 year ago (edited) This may be the best video you have ever done. You've captured both the struggle and effort in science and the awe and wonder of discovery. Outstanding! 1 Arvin Ash · Gobor Bobor Gobor Bobor 8 months ago This video is just pure genius. I really don’t know who Arvin Ash is - wether he is a teacher or a professor or “just” a superbly intelligent and curious human being - but I admire his lessons. What a great explanation this is… Thank you so much for sharing!! Nine Hundred Dollar Luxury Yacht Nine Hundred Dollar Luxury Yacht 8 months ago Thank you so much for this. I am old, but have wondered about things like this my entire life. Until now, my understanding ended with "Maxwell's equations said light went this speed". I feel like I know a little bit more about it now. 6 sikhar saikia sikhar saikia 4 months ago Thank you for explaining this so beautifully. I never knew of Maxwell's thought experiment and it makes so much sense now that I understood that. 4 The History Guy: History Deserves to Be Remembered The History Guy: History Deserves to Be Remembered 2 years ago Thanks for the collaboration! Thanks for expanding our understanding of Maxwell’s contributions! 683 Arvin Ash Arvin Ash · snorkfire snorkfire 7 months ago VERY well done! I’ve wondered about that for years and even took time here and there to understand Maxwell’s eqn’s. You cleared it up in one brief video. Thank you sir. Subscribed. 1 adam labnaki adam labnaki 7 months ago Hi Arvin, your videos are amazing, really helpful in understanding complicated concepts in physics 4 Gary Scanlon Gary Scanlon 7 months ago I have zero background in physics, yet you explain things in a way I can actually understand. It's fascinating. Thanks! 6 Rudi Hoffman Rudi Hoffman 4 months ago Brilliant explaining of subject matter with enthusiasm and crystal clear thinking. I wanna be this good at what I do as Arvin Ash! 1 Jacob Olness Jacob Olness 6 months ago This channel is awesome! Well done. Physics is not my strong suit but I think it is fascinating. This and PBS’ Space Time are my favorites so far. Subscribed 2 Arvin Ash · innertubez innertubez 2 years ago "There was a point in time when Maxwell was the only person in the world who realized this." That is pretty amazing. 738 David Deavours David Deavours 1 year ago That realization that Maxwell could calculate c from the equations literally gave me chills.. wow. 1 Paul Logeman Paul Logeman 1 month ago An exceptional presentation of a complex topic. The information was clear and concise with wonderful examples. 1 Carrick Richards Carrick Richards 3 months ago Thank you; for myself and all the many others who can grasp this subject better, due to your clear explanations. 1 Last Chance Last Chance 6 months ago Great job explaining the speed of light. It blows the mind to realize that the universe is like an ocean filled with uncountable waves of causality in every direction. 1 Steven Miller Steven Miller 10 months ago (edited) Thanks dude, I love your Physics videos and I use them often in teaching high school Physics and Chemistry courses I teach!! I did my PhD Physics coursework at Purdue University with a 5.9 / 6.0 GPA but I greatly benefit from your videos, well done!! Now I better understand why the electricity and magnetism fields in copper wires travel faster than the speed of light in free space or 3 X 10^8 m/s , because epsilon and mu in the copper are substantially different in copper than in free space and therefore the fields travel faster than the speed of light number we all have drilled into our heads from our school days!! 24 Arvin Ash Arvin Ash · Mystery Hombre Mystery Hombre 2 years ago (edited) Watching this made my jaw drop, imagine that Eureka moment, when Maxwell realised the approximate measured speed of light matched his equation. Epic. 379 vishal rao vishal rao 9 months ago Arvin Ash's lucid style of explaining makes a layman like me understand and appreciate nature in its fundamental essence. I look forward to more videos from Arvin. I will see you in the next video my friend 🙂. 1 Albert Hendricks Albert Hendricks 2 weeks ago Finally someone that understands physics well enough to explain it simply.Too many people take off on a tangent and we end up in a ditch somewhere. 1 Trollkiller 69 Trollkiller 69 2 years ago Im currently at a prestigious university studying physics and with electromagnetism being one of my favorite subfields I will say you explained this amazingly for people who don't understand maxwell's equations and how the speed of light was derived from said equations. 2 Quién Sabe Quién Sabe 1 year ago PhD here: Superb explanation! I loved the way you expressed these concepts. Young students could get in love with physics with videos like this! 28 Eric Ostrowski Eric Ostrowski 1 year ago Outstanding video! Thanks for the clear connection between Maxwell and Einstein! Very informative and fun! 1 Billy Lee Billy Lee 2 years ago This presentation of Maxwell’s equations is the best I’ve ever seen. 310 Arvin Ash ℙ𝕣𝕒𝕧𝕖𝕜𝕒 - 𝕆𝕗𝕗𝕚𝕔𝕚𝕒𝕝 ℂ𝕙𝕒𝕟𝕟𝕖𝕝 ℙ𝕣𝕒𝕧𝕖𝕜𝕒 - 𝕆𝕗𝕗𝕚𝕔𝕚𝕒𝕝 ℂ𝕙𝕒𝕟𝕟𝕖𝕝 1 year ago Not less than WONDERFUL! Wow. Your Energy Level- you are making Physics a lot easier to visualize. Please keep making more videos like this one :-) 2 Michael Bustamante Michael Bustamante 1 year ago That was nicely done. Thanks for putting together a easy to follow path of how the speed of light is bounded by the interaction between electric field and magnetic fields. 5 Nick Dyne Nick Dyne 6 months ago Brilliant. It's a real skill to make these ideas so easy to comprehend. Perhaps one on entanglement and emergence of spacetime 1 Parsa Arta Parsa Arta 3 months ago I subscribed to your channel Sir. I personally thank you so much for your ability to make me to finally understand these. 1 moonpup moonpup 11 months ago Ok so we’ve seen patterns in the background radiation of the universe. I’m left wondering if these constants may change ever so slightly in relation to things like background radiation or concentration of “dark matter”. Any ideas on that? 1 Christian Heaford Christian Heaford 2 years ago This is superb. Maxwell has always been one of my favorites, but I’ve never understood how his mind made such a leap to see the relationship between electromagnetism & light. Your explanation Arvin is so clear and simple that now I feel like I truly have an intuitive understanding. Love History Guy too! Good to see 2 of my favorite channels collaborating! 60 Arvin Ash Alastair Palm Alastair Palm 1 year ago I can't get enough of this video. Well done all round. 1 NubiVlog NubiVlog 9 months ago I've watched many videos about light and maxwell equations and this is by far the best one. Well done! 1 jacques jacques9246 jacques jacques9246 11 months ago Very clear..I am a retired electrical engineer and this explanation of Maxwell theory reminds me of the old time 1 Craig Fowler Craig Fowler 2 months ago I did see The History Guys video on Maxwell, it was interesting. However as I studied physics at degree level and can appreciate this topic in detail, your video was excellent way to explain this phenomenon to GCSE and A Level Physics students with interesting graphics etc. 1 swissaroo swissaroo 3 months ago Brilliant overview of Maxwell and his predecessors and those who picked up Maxwell’s baton and took it still further with their respective theories and insights! 1 Mark Simpson Mark Simpson 2 years ago This is absolutely amazing as it's the first time I've ever begun to feel like I partly understand what the four elegant equations actually mean! Maxwell was a genius and might be better remembered today had he not died so young. 10 Dunno Anyone Dunno Anyone 7 months ago You bring difficult to understand science to a level ordinary mortals can grasp Arvin. Thank you. I already have a subscription with the history guy 1 Absentimental 1 Absentimental 1 11 months ago Awesome video, but I'm questioning the speed of swimming in fluids of different viscosity. I'm not necessarily sure that you'd swim slower, as used in the example. The increased resistance may be canceled by improved ability to motivate yourself. Any thoughts? michael nastasie michael nastasie 1 year ago Absolutely amazing video, congratulations on your work putting it together and thank you so much for teaching me so much in such a short amount of time. Amazing. 1 Sean Ehle Sean Ehle 1 year ago I'm new to your channel, and an instant fan. If you read this, can you intuitively explain why the speed of light is the same as the speed of causality? Must it be so in a universe where all observers agree on causality? The Ultimate Reductionist The Ultimate Reductionist 2 years ago (edited) Thousands of physics videos on YouTube. I HAVE NEVER HEARD THESE SPECIFIC EXPLANATIONS IN ANY OTHER VIDEOS ANYWHERE ELSE ON YOUTUBE OR THE INTERNET!! This is AMAZING! I thought (wrongly) that I had "heard it all a billion times before" about physics. Not so. Thank you!! 3 Arvin Ash Frank Russell Frank Russell 2 years ago Superb job. Maxwell also invented color photography by proving white light is made up of Red Green Blue colors. There's a picture of a bow tie of many colors he made in the 1860's. He was a full proffesor at 25 years old. What an incredible genious! 7 Jake Barlow Jake Barlow 8 months ago I understood more math in this video than I did in high school. I wish I had teachers like you back then. Garrett Garrett 4 months ago Oh! I had heard a long time ago that relativity was somehow a logical conclusion from Maxwell's equations but I never knew how until now. Thanks! 1 The Prince Of Liberia The Prince Of Liberia 2 years ago This is by far the best theoretical and mathematical explanation for the laymen like myself that I've ever saw so far 1 Lindsay Hoffman Lindsay Hoffman 10 months ago Loved the attempt of relating Guass's, Faraday's and Ampere's equations and their visualization in Maxwell's famous electromagnetic theory with the minimum of mathematical effort. Pablo Dibildox Pablo Dibildox 1 year ago (edited) for anyone wondering, the upside down triangles are the divergence (for the dot products) and the curl (for the cross product) factors of the vectors in the vector field. Sabertooth Turtle Sabertooth Turtle 2 years ago Bravo, probably the best visual explanation of the electric and magnetic constant that exist on the web. There's a huge shortage of these kind of videos online and you're doing great. I propose that you make one of these visual explanations for each of the major physical constants. That would be awesome and teach very valuable knowledge to these curious people watching your videos. 69 Arvin Ash Arvin Ash · Shyam Footprints Shyam Footprints 1 year ago Nice video again. But how are the permeability constant and the permitivity constant calculated? This nice video will be awesome if this question is also answered. L. Gagnon L. Gagnon 1 year ago So smooth and articulated! Thank you for this nice video! 2 Ahmad Ramadan Ahmad Ramadan 9 months ago This is the most brilliant explanation I've seen. And I've seen literally hundreds, on YouTube, lectures, as an undergrad, as an engineer..wow. 1 Stapleman 007 Stapleman 007 10 months ago I remember sitting in college physics II and the lecture professor deriving the speed of light formula from Maxwell's eqs. It was a WOW moment. 1 tim stoffel tim stoffel 6 months ago Thank you for this fascinating look at those relationship between c, u0 and e0. Because of the significance and ramifications of those four equations, Maxwell has always been my favorite scientist. 5 John King John King 2 years ago (edited) As a qualified electrical and electronic engineer of 36 years in telecoms I have only just found out how radio propagation works from this video. WOW! At college and uni they did not explain it this well. 86 Arvin Ash Earl Wiese Earl Wiese 5 months ago I struggled with Maxwell's equations in University. Thanks for the simple explanations. 1 Family Guy Family Guy 1 year ago I have an awesome habit of watching your videos more than once! Great work! 1 Agpedro Pedro Agpedro Pedro 2 years ago The best explanation of what is the light I've ever seen. Fantastic! Congratulations! 1 cosmic adventure cosmic adventure 1 year ago You really made me love pyhsics the subject that i hated most during my hight school i believe at that time that physics is boring but you proved that wrong now i realised that physics is so simple and easy to understand if you got the right teacher thank you so much bro 1 Himanshu Kumar Himanshu Kumar 2 years ago Arvish Sir, what a wonderful and lucid explanation. !!!! I can't imagine the euphoria of honorable Maxwell sir when he discovered relationship between permittivity and permeability with speed of light 1 Ace Ace 2 years ago Thanks. I learned more in 13 minutes then in a semester of Fields and Waves when I was in college 25 years ago. 88 Arvin Ash · Rachita Sharma Rachita Sharma 6 months ago You truly make us understand the Maxwell's equations in a very simple , easy and logical way. Thankyou so much, Now I love these equations. 1 Charlie Double Whiskey Charlie Double Whiskey 8 months ago This was truly a most enlightening video. My understanding of light as an electromagnetic wave is much broader. 1 Tomatrix Tomatrix 2 years ago This is a really good video. Very well done in all aspects, many thanks 1 Веселин Шишков Веселин Шишков 1 year ago Харесвам те Човек ,бързо и лесно обесняваш неща ,които в университети те ни не могат да ги обяснят, добре съм запознат с теорията на Планк, както и на Бор ,но все пак не ми е известно още за съществуванетп на Бузонни частици, или на Тъмна материя , Извинявай че пиша на Моя езикл , но на англииски нямаше да се получи :) Голям фен съм на теб , :)А и в прочем не съм тинеиджър , и да и аз съм инженер :) 1 Arvin Ash · David Macfarlane David Macfarlane 4 months ago Thanks so much, I've often wondered how we get the speed of light out of Maxwell's equations. 1 Cosmoslogic Cosmoslogic 2 years ago I knew part of this but not all the details and as always Prof Arvin Ash ties all the lose ends together to make a very neat pack of history , Sir you are a rock of knowledge like no other , i plug your channel every chance i get for good reason you have the answers that most do not come up with , Thank you for what you do for physics now and in the future. 5 Arvin Ash