But why would light "slow down"? | Optics puzzles 3

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  • čas přidán 10. 05. 2024
  • How the index of refraction arises, and why it depends on color.
    Quotebook Notebooks: 3b1b.co/store
    These lessons are primarily funded directly by viewers: 3b1b.co/support
    An equally valuable form of support is to simply share the videos.
    Looking Glass Universe videos on the index of refraction:
    • I don't know why light...
    Much of this video is based on the following Feynmann lecture
    www.feynmanlectures.caltech.e...
    The explanation for why the phase of a wave produced by a plane of oscillating charges is a quarter phase behind the wave of a charge in the center of that plane, and hence a quarter phase behind that of a light wave inducing the oscillations, is given in the previous chapter:
    www.feynmanlectures.caltech.e...
    Sections:
    0:00 - The standard explanation
    3:14 - The plan
    5:09 - Phase kicks
    8:25 - What causes light?
    13:20 - Adding waves
    16:40 - Modeling the charge oscillation
    20:59 - The driven harmonic oscillator
    26:57 - End notes
    Thanks to these viewers for their contributions to translations
    German: Ole
    Hebrew: Alon Altman, Omer Tuchfeld
    Hindi: Saurabh
    Portuguese: @doryhelioaires
    Urdu: Momini0
    ------------------
    These animations are largely made using a custom Python library, manim. See the FAQ comments here:
    3b1b.co/faq#manim
    github.com/3b1b/manim
    github.com/ManimCommunity/manim/
    All code for specific videos is visible here:
    github.com/3b1b/videos/
    The music is by Vincent Rubinetti.
    www.vincentrubinetti.com
    vincerubinetti.bandcamp.com/a...
    open.spotify.com/album/1dVyjw...
    ------------------
    3blue1brown is a channel about animating math, in all senses of the word animate. If you're reading the bottom of a video description, I'm guessing you're more interested than the average viewer in lessons here. It would mean a lot to me if you chose to stay up to date on new ones, either by subscribing here on CZcams or otherwise following on whichever platform below you check most regularly.
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Komentáře • 1,6K

  • @Rubrickety
    @Rubrickety Před 5 měsíci +2874

    Part of what makes Grant such a superlative educator is how he treats the things he leaves out or simplifies. He always points them out, explains why he's skipping over them, and provides a hint as to what including them would look like. It's never "It's too complicated, just don't worry about it."

    • @Dudeguymansir
      @Dudeguymansir Před 5 měsíci +69

      “The solution is trivial”
      Is it, though?

    • @berryesseen
      @berryesseen Před 5 měsíci +64

      That's what true mathematicians do. If they are lazy or out of space (or time), they always explain what a non-lazy person should do. They give kind of a recipe even though they don't write down the calculations explicitly. Physics people are in general more lazy to explain what they simplify and why they simplify.

    • @VeganSemihCyprus33
      @VeganSemihCyprus33 Před 5 měsíci +2

      To understand, study... To live in peace, watch this 👉The Connections (2021) [short documentary]💖

    • @samueldeandrade8535
      @samueldeandrade8535 Před 5 měsíci +1

      Superlative educator? More like overrated af.

    • @samueldeandrade8535
      @samueldeandrade8535 Před 5 měsíci +9

      ​​@@berryesseen "Mathematics is being lazy. Mathematics is letting the principles do the work for you so that you do not have to do the work for yourself"
      - George Pólya

  • @claudiooton1732
    @claudiooton1732 Před 5 měsíci +815

    I teach optics in the University, and I can say that you nailed this one, really the best explanation I've ever seen on the matter. I'm sure Feynman would hug you if he could see this video.

    • @3blue1brown
      @3blue1brown  Před 5 měsíci +233

      Thanks! If you have any other optics puzzles you use with your students, do feel free to pass them along.

    • @PluetoeInc.
      @PluetoeInc. Před 5 měsíci +48

      After reading Mr. feynman's self-authored biography , I feel I have a little virtual model of his consciousness inside my mind and it's saying Thank you grant , Thanks for respecting the height of the standard of self-inquiry and discovery that I so deeply believe in and tried instilling in everyone I shared a piece of my mind with .

    • @baptistedelplanque8859
      @baptistedelplanque8859 Před 5 měsíci +9

      ⁠​⁠​⁠​⁠@@3blue1brownwell, you have the base to explain many phenomenons. Maybe you can use it to introduce cool things to viewers: linking chemistry to different oscillators = spectroscopy. Or even going non linear.
      Surface interactions also has some nice effects like Goos-Hänchen... Well that might be quite niche.

    • @JuliusUnique
      @JuliusUnique Před 4 měsíci +2

      thanks, Feynman hugging me is a nice thing to hear, I don't get much love so I appreciate the compliment. While I didnt make this video, I'd have done it if I had the resources to do so, and I put a lot of effort into improving humanity. It's rough working hard and getting no appreciation for it

    • @GooogleGoglee
      @GooogleGoglee Před 4 měsíci

      Can someone explain to me why describing the wave in that way as cos(wt) would not let increase the "cycles" (see also frequency) of the wave so described because of 't'? (Which is in the argument of the function cos()...
      After all 't' is not a constant and will increase... So what am I not seeing here?

  • @andycgn1991
    @andycgn1991 Před 5 měsíci +543

    If there was a Nobel Prize for explanations, you would be my canditate. Thank you for taking the trouble to explain things so profoundly and vividly. You are my hero.

    • @JuliusUnique
      @JuliusUnique Před 4 měsíci +5

      and where is mine for not being native english, having a rough childhood, getting love scammed and not being able to find a wife? His videos are good, but the effort we both put in life is probably at least equal so I deserve the same price. Thanks for calling me a hero since it counts for me too

    • @danguee1
      @danguee1 Před 4 měsíci +6

      @@JuliusUnique I had that - have this Nobel Prize from me:🥑

    • @JuliusUnique
      @JuliusUnique Před 4 měsíci +1

      @@danguee1 thanks

    • @julianklimke3476
      @julianklimke3476 Před 4 měsíci +7

      @@JuliusUniquewhat is your point?

    • @JuliusUnique
      @JuliusUnique Před 4 měsíci +1

      @@julianklimke3476 oh wow, I made my point very clear, maybe you should work on your english

  • @laxminarayanbhandari855
    @laxminarayanbhandari855 Před 5 měsíci +405

    "so, everything was just a harmonic oscillator?"
    "always has been."
    Great video as always. Waiting for the next part!

    • @siddhapandeypanigrahi353
      @siddhapandeypanigrahi353 Před 4 měsíci +7

      A man of culture 🗿

    • @DrDeuteron
      @DrDeuteron Před 3 hodinami

      Simple, damped, driven, coupled …and then quantized Ftw.
      Pendulum with large amplitude:
      Hold my 🍺

  • @lakshya2441
    @lakshya2441 Před 5 měsíci +809

    this is the clearest explanation I ever heard. It's like 15 optics lectures condensed in a single video. Absolutely mind blowing...

    • @TM_Makeover
      @TM_Makeover Před 5 měsíci +3

      True that

    • @atticuswalker
      @atticuswalker Před 5 měsíci +8

      I have a simpler explanation. time slows down in glass. that's why green Lazers look red in glass.

    • @MadScientist267
      @MadScientist267 Před 5 měsíci +3

      Yeah just use the right terms...
      Phase SHIFT

    • @VeganSemihCyprus33
      @VeganSemihCyprus33 Před 5 měsíci

      To understand, study... To live in peace, watch this 👉The Connections (2021) [short documentary]💖

    • @HilbertXVI
      @HilbertXVI Před 5 měsíci +6

      ​@@MadScientist267??? It's pretty common terminology lol

  • @tahsinshafin100
    @tahsinshafin100 Před 5 měsíci +498

    I'm genuinely telling you Grant, for all the human beings seeking the absolute deepness of reality asking every bit of "Why", *you are an unprecedented blessing.*

    • @VeganSemihCyprus33
      @VeganSemihCyprus33 Před 5 měsíci +1

      To understand, study... To live in peace, watch this 👉The Connections (2021) [short documentary]💖

    • @samueldeandrade8535
      @samueldeandrade8535 Před 5 měsíci

      People sure like to suck this guy's b@lls. It's impressive.

    • @roseghould
      @roseghould Před 5 měsíci

      cosign

    • @anonymous_4276
      @anonymous_4276 Před 5 měsíci +4

      Agreed 100%, the question of why would frustrate my endlessly in school.

    • @abrahanpinedo
      @abrahanpinedo Před 5 měsíci +1

      You are Goddamn right!

  • @rectorsquid
    @rectorsquid Před 5 měsíci +96

    I have always regretted my lack of math education. The equations in the video barely make sense - the algebra makes sense but the differential equation stuff is a language I just don't speak - so seeing the visuals to explain these things make them accessible to me. Thanks. And those visuals are absolutely stunning!

    • @tillorrly1128
      @tillorrly1128 Před 4 měsíci +6

      Differential equation is the place where there be dragons in maths. I think only a small subset of them can be solved beautifully, while most are basically brute forced by guessing the solutions and the checking if that guess actually solves it.

    • @domenicobianchi8
      @domenicobianchi8 Před 4 měsíci +5

      understanding basic differential equation self thought is possible. find a good book, with 50 hours you can master them.

    • @Kingbimmy
      @Kingbimmy Před 4 měsíci +1

      Same. I had the misfortune of having most of my math and science teachers not caring to actually teach anything, and a majority of them didn’t speak English well enough to give me the basics. I failed PRE calculus 3 times in a row 😭 I feel so betrayed. My favorite thing in the world is science and I want so badly to study things like astrophysics but there’s so much basic stuff I’d have to go back to 💀😔💔
      This video was wonderful though because I didn’t necessarily have to know everything to get the idea! I’m glad I found this channel.

    • @incognitoburrito6020
      @incognitoburrito6020 Před 4 měsíci +5

      ​@@domenicobianchi8 Very few people have the time or willingness to spend 50 hours teaching themselves differential equations out of a textbook. Same way most of us aren't willing to take up small-scale wheat farming just to be a little more connected to our toast

    • @greegorygrimlee5487
      @greegorygrimlee5487 Před měsícem

      ​@@incognitoburrito6020I guess he aint talking to you then 😂
      For others who are lamenting not having mastered differentiation, 50 hours is about what people spend each month on social media and wandering the internet these days, and the learning is free, so definitely more achievable than a wheat farm.

  • @a11aaa11a
    @a11aaa11a Před 4 měsíci +90

    I always wondered what Feynman's lectures would have been like if he taught them with today's technology, and man this is it. The world is going to have some brilliant physicists and mathematicians thanks to you.

    • @joshyoung1440
      @joshyoung1440 Před 4 měsíci

      You've always wondered what his lectures would be like... so you see a particularly good lecture and say "this is it, this is what they must have been like, they must have been great because Feynman was great"?? If I were a hack this is where I'd say that Feynman would cringe at that assumption, but I won't, because _I never fuckin' met the guy_

    • @a11aaa11a
      @a11aaa11a Před 4 měsíci +6

      @@joshyoung1440 I have no idea what your comment means

    • @insertcreativenamehere492
      @insertcreativenamehere492 Před 3 měsíci

      @@joshyoung1440 learn to read

    • @BassilioDahlan
      @BassilioDahlan Před měsícem

      @@joshyoung1440 You might have missed it but Grant mentioned in the beginning that his presented explanation is based on Feynman's lectures

    • @DrDeuteron
      @DrDeuteron Před 3 hodinami

      @@joshyoung1440I did meet him, I was in his last lecture, and I can read, and I have no idea what your point is.

  • @paparapiropip87
    @paparapiropip87 Před 5 měsíci +465

    After a double major in math and physics, I'm doing a PhD in physics. A great part of it deals with light-matter interaction. I must say this is a beautiful representation of a phenomenon that most of the time physicists "sort of" imagine. Thanks for such a great way of visualizing physics! And thanks for giving our dear harmonic oscillator the visibility it deserves!

    • @runakovacs4759
      @runakovacs4759 Před 5 měsíci +5

      Spectroscopy for life!

    • @onradioactivewaves
      @onradioactivewaves Před 5 měsíci +8

      🤭 sounds like a great deal of it is a Snell's pace of life

    • @davidrandell2224
      @davidrandell2224 Před 5 měsíci +3

      “The Final Theory: Rethinking Our Scientific Legacy “, Mark McCutcheon for proper physics.

    • @atticuswalker
      @atticuswalker Před 5 měsíci +1

      can you explain why green Lazer light looks red inside glass. and the white light dosent seperate into colors until it leaves the glass at a different angle than it entered. why everyone agrees light slows down in glass but nobody will consider time moves slower , as the reason.

    • @newuser689
      @newuser689 Před 5 měsíci +3

      ​@@davidrandell2224 quackery lol. if he was smarter than einstein, hawking, newton like he implies then literally everyone would recognize him. but nope, Some Guy (tm) figured out the hardest theory in the universe.

  • @tirterra1222
    @tirterra1222 Před 5 měsíci +359

    I was genuinely thinking about working on prisms an hour ago as an electromagnetism exercise, this is too perfect to be true.

    • @the_akshay_p
      @the_akshay_p Před 5 měsíci +20

      Me at 12.15 AM: this is enough for today, let's sleep.
      3blue1brown after 15 seconds: this is perfect time to upload new video.
      Me : okay, this is last one😂😂.

    • @_John_P
      @_John_P Před 5 měsíci +5

      Probably there's an educational video on youtube for any subject you can think of, and you're probably subscribed to most subjects you study, or are interested in. So, chances are that eventually a video will pop up, matching your latest need.

    • @goldnutter412
      @goldnutter412 Před 5 měsíci

      😂🥲

    • @goldnutter412
      @goldnutter412 Před 5 měsíci

      33 minutes ago@@_John_P

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      minutes ago erm okay youtube whatever
      But video 45mins ago comment 33 minutes ago hmmm yes not timing at all was just the algo
      Classic 1 | 0 thinking

    • @waelfadlallah8939
      @waelfadlallah8939 Před 5 měsíci +1

      I am waiting for barber pole effect part 3 pleasssssssssse!

  • @abrahanpinedo
    @abrahanpinedo Před 5 měsíci +48

    This video reminded me of a talk I had with some friends at CERN, where I told them that we didn't really understand why light refracts, the typical explanations weren't enough. When I looked into it myself, I remember reading the response in the Feynman Lectures and being more or less pleased with what it said. But now with the video and animations everything clicked! From a question I had asked myself ten years ago, it is an incredible sensation! Thank you Grant.

  • @tHaTsWhAtI.mSaYiNg
    @tHaTsWhAtI.mSaYiNg Před 5 měsíci +39

    This may be one of the first 3b1b videos I actually understood, wonderful job.
    Also it is kind of adorable thinking that Grant approached his niece like 'can I push you in a swing for a math video, but like, really badly'

  • @HuygensOptics
    @HuygensOptics Před 5 měsíci +58

    The animations in this video are clarifying so many details that are very hard to explain in any other way. Fantastic, I loved every second of it!

    • @Arnogorter
      @Arnogorter Před 5 měsíci +6

      This video complements your recent one very well!! Both are fantastic videos.

  • @xminty77
    @xminty77 Před 5 měsíci +56

    22:11 my favorite 3b1b moment
    thank you Grant for your works it has been monumental to my studies

  • @jakeadams2562
    @jakeadams2562 Před 5 měsíci +24

    13 minutes in and you’ve already granted 3 revelations in my understanding of our world that would have otherwise taken years for me to understand… you have a very special talent and I thank you massively.

  • @AlphaPhoenixChannel
    @AlphaPhoenixChannel Před 5 měsíci +17

    This might be my favorite physics explainer video ever, and it's on a math channel - undergrad me would be twitching =D
    I love this video because the animations of the phase shift and the oscillator so succinctly get the point across when it normally takes (or at least for me it took) years of imagining and trying to extrapolate from static images on a whiteboard and a lot of conflicting explanations. It's very easy to grasp small pieces of it but if you learn too many disconnected pieces that use different assumptions and approximations you end up with really pretty puzzle pieces that don't fit together. I really hope that others had the same reaction as I did - when I publish something I'm always afraid that it will only make sense to me just because I already know the material, and I think this style fights that very effectively.
    I'm very excited to see your explanation of "metamaterial" indeces of refraction because the explanation of why speed is bending that I know (plane waves on a 2d mesh are like your tank treads) shouldn't work with speeds faster than C. If it's a phase vs group thing I'm getting ready to be confused but I'll probably understand it better than I ever have before! wait a minute - as I type this I might be having a lightbulb - you showed the startup transient - nobody ever shows the startup transient. is that how you obey relativity but have a phase velocity >C? ahhh that would only work near resonance, which those funky capacitor loops on paper DO. oh my god.
    EVERYTHING IS SPRINGS 😁

  • @Anjihyu
    @Anjihyu Před 5 měsíci +46

    The single best channel on this entire site. I wish I had money to spare, because you, mister, deserve it more than anyone. Brilliant video, brilliant editing, brilliant visuals, brilliant explanation.

  • @alessandrolodi8951
    @alessandrolodi8951 Před 5 měsíci +79

    Cannot stress enough how inspiring this guy and his team are. True modern scientist

    • @pitCest
      @pitCest Před 5 měsíci +1

      And artist I must say. It's a form of art this way of communicating

    • @VeganSemihCyprus33
      @VeganSemihCyprus33 Před 5 měsíci

      To understand, study... To live in peace, watch this 👉The Connections (2021) [short documentary]💖

    • @berryesseen
      @berryesseen Před 5 měsíci +7

      To be fair, I wouldn't say this goes under the name of science. It's more like an educational videos. He's a teacher right now. Don't get me wrong. By definition of his PhD, he was a scientist. Today, he has a different career path, which is very very inspiring. But in the end, it's teaching.
      Just in case of a misunderstanding, I admire his work a lot. And this channel is one of my top 5 among all CZcams.

    • @piman7319
      @piman7319 Před 5 měsíci

      Not actually a PhD. He calls himself a (math) explainer@@berryesseen

  • @NiMareQ
    @NiMareQ Před 4 měsíci +9

    I don't think there is a material on youtube or the internet explaining this stuff in such detail and so comprehensibly. I am blown away. It instantly clicks!

  • @NowhereNear42
    @NowhereNear42 Před 12 dny

    I have no words for how brillantly this is explained! This is very, very high quality teaching.

  • @Pidrittel
    @Pidrittel Před 5 měsíci +46

    As a physicist, I (should) already know all of this. An I would argue I mostly fo do, but often in a much more abstract and thus less intuitive way. And because of that, it would be a lie to say I did not learn anything from this. Very well done! Those animations are just pure gold, and the fact that you apply your nitpicky maths brain to physics questions and your reasoning why certain things "are" really is a big win for any physicist watching!

    • @godoit7569
      @godoit7569 Před 5 měsíci +1

      Hey, i am an aspiring physisict. An 18y/o, In Senior high school.
      Physics gonna be fun by thinking that what we will do to it and 😢 also what will it do to us. Though, nice.

    • @Beny123
      @Beny123 Před 5 měsíci +1

      Your nitpicky maths brain 😢 . Indeed it is

    • @stylis666
      @stylis666 Před 5 měsíci

      It's the cross over I never even expected in my wildest dreams. 3Blue1Brown explaining physics

  • @AdityaPatwardhanJ
    @AdityaPatwardhanJ Před 5 měsíci +16

    Dear Grant Sanderson,
    You turn raw mathematics into an intuitive knowledge, helping us evole our own ideas about the physical works, with so many emergant subject to explore. You turn math into a real world experience, much like our brains must be doing when it takes measurements of this strange place around us. Thank you for the profound wisdom you share in the simplest of ways.
    Hats off to you, Sir!
    Always a fan, best regards :)

  • @cegalleta
    @cegalleta Před 5 měsíci +5

    Props to you for explaining topics proper of a electrodynamics/solid state physics class to a wide audience without making it confusing or hard to digest

  • @TheWinWinWorld
    @TheWinWinWorld Před 14 dny

    I've never in my life (!) seen a more brilliant explanation. While physics laid out by You mesmerized my mind completely, Your comment with the swing "this isn't how MOM does it..." just stole my heart for the power of intuitive explanation of the MATER as if in a primary design of some kind. Thank you and please don't stop making such great videos.

  • @adjsmith
    @adjsmith Před 5 měsíci +20

    As an undergraduate, I would have loved these videos. (As a graduate student, I still love them!) They make so much sense. Your explanation of the sum of sine waves was excellent.

  • @nathanaelhahn4795
    @nathanaelhahn4795 Před 5 měsíci +16

    Grant, what you do is what I consider true mathematics to be. You're putting the wonder, exploration, and intuition back into what for many of us simply died when we saw our first variable. Truly an inspiration for any math teacher!

  • @estrheagen4160
    @estrheagen4160 Před 5 měsíci +5

    This is probably your best work so far. To explain third-year undergraduate physics in such a clear and approachable manner is nothing short of genius. This is why the Feynman lectures are beloved by students, often being a student's main literature despite only being supplementary literature in the course plan.
    I first heard the spring analogy in the context of the Dulong-Petit law. Each quadratic degree of freedom contributes kT/2 energy per particle (equipartition theorem); A particle in a crystal can be approximated as having six quadratic degrees of freedom: three kinetic (v_x, v_y, v_z) and three translational (x, y, z) because it's "sprung" to its nearest neighbours in all three dimensions; therefore, a crystal should have a heat capacity of 3 k per particle, or 3 R/mol. And, yeah crystal heat capacities do cluster around 3R/mol. Simple but damn good approximation.

  • @JoelFishel
    @JoelFishel Před 5 měsíci +11

    This is just utterly phenomenal. I can't believe the level of deepness in explanations that we're able to get for free on the internet living in today's world. Your videos are going to truly change the world as a new generation will learn concepts with so much more clarity than generations before. I'm just in awe.

  • @GroovingPict
    @GroovingPict Před 5 měsíci +57

    You will probably like the update they did to the Dark Side cover for the 20th anniversary edition in 1993 then, where they made it more realistic, with the spectrum being just that: a continuous spectrum rather than individual colours (which btw is also missing a colour compared to the more common colour representation). They even included a faint reflection of the incoming beam bouncing off the surface of the prism.

  • @sirmr6597
    @sirmr6597 Před 5 měsíci

    I absolutely appreciate this. I’m always asking questions that seem to be never answered. The way you are aware of these questions and also are ready to readjust what questions we should ask is absolutely invaluable.

  • @suddhasattasaha4793
    @suddhasattasaha4793 Před 4 měsíci +2

    I could truly appreciate the real beauty of physics after watching this video. It takes a lot of hard work to produce such beautiful, detailed and asthetically clean and smooth animations to depict hard to imagine pictures which we are required to visualize to understand physics and dive into the thorough depths of it. Wonderful.

  • @luckyw4ss4bi
    @luckyw4ss4bi Před 5 měsíci +5

    The animation at 7:30 is truly astounding and enlightening! It'll forever change the way I think about light passing through a medium.

  • @leokyle6195
    @leokyle6195 Před 5 měsíci +11

    3b1b, I gotta be giving you great thanks. I've ended up pretty much of a humanities guy mostly in my research and education life but deeply believe that the life of the mind requires all directions of enquiry and that therefore the stem/humanities distinction is always and forever something to work on both sides of. Your videos are incredibly good at explaining this fundamental stuff to even a no-attention-span fool such as myself and I will ever be grateful for these insights. All my thanx p.s. your lockdown math videos were awesome and helped keep my mind rigorous during lockdown xoxo

  • @DellHell1
    @DellHell1 Před 5 měsíci +12

    A twenty minute video gives me more intuition than two years of studying field theory at university. As an undergraduate I would not have been able to follow the Feynman lectures as you have done. Thanks for these really very important video lessons.

    • @DrDeuteron
      @DrDeuteron Před 2 hodinami

      Omg, grant should get paid to do a complete animation of the Feynman lectures.

  • @hurshasnarayan
    @hurshasnarayan Před 5 měsíci +7

    One day your niece will grow up to realise she has an uncle who's a genius. I wish we had educators like you and the tools that we have now when I was a student. Having a background in NVH and currently working on control systems this video was very exciting for me. Thank you. 🙏🏽

  • @gustavinho1510
    @gustavinho1510 Před 5 měsíci +5

    Thanks Grant, you have made my thursday by releasing this video. I was so intrigued by your past two videos and couldn’t wait for this one, truly a beautiful way to visualise electromagnetic waves and optics.

  • @srroome
    @srroome Před 5 měsíci +15

    never laughed so much at one of your videos as at "bad at pushing a child on a swing".
    Yeah, that's extra special wrong.
    The effort you put into these is incredible, thank you so much for what you do.

  • @DiaryOfAGhost_StreetsOfTempe
    @DiaryOfAGhost_StreetsOfTempe Před 4 měsíci +1

    You seriously need an award for your ability to teach. It's never about the information for me but how it is explained and in what tone. I hope you love your job. Because I for one appreciate the output. Thank you 😊

  • @user-be8uq2th4f
    @user-be8uq2th4f Před 5 měsíci

    This is so amazing! I've struggled so much with textbooks and ivy league profs trying to describe this - it always ended up just being arcane gibberish. The brilliantly intuitive explanations combined with the simulations do so much to demystify a frequently opaque subject, even to people like myself who used to work a lot with optics!

  • @borisjoukov
    @borisjoukov Před 5 měsíci +51

    👏👏👏 Beautiful, as always! I love how you manage to touch on so many crucial physics and math topics in a single video!

    • @waelfadlallah8939
      @waelfadlallah8939 Před 5 měsíci

      I am waiting for barber pole effect part 3 pleasssssssssse!

    • @MadScientist267
      @MadScientist267 Před 5 měsíci

      I like his stuff usually but this is *horrible* on many levels.
      I suspect it's in part that he's still dumbing it down too much or something but for example terms like "phase shift" elude. "Phase kick back"? Lol 🤦‍♂️
      Edit: He uses the correct term later on... I don't know WTF the deal is but yeah... 🤷‍♂️

    • @VeganSemihCyprus33
      @VeganSemihCyprus33 Před 5 měsíci

      To understand, study... To live in peace, watch this 👉The Connections (2021) [short documentary]💖

  • @EletronicaCaseira
    @EletronicaCaseira Před 5 měsíci +3

    This video is awesome in so many ways. The amount of intuition provided is really valuable. It is really difficult to imagine getting the same kind of information in a lecture or in an article. Many of the concepts that seemed common sense or well-known simply receive another level of comprehension in a video like this and after that life gets a little bit more beautiful. Summary: Thank you very much!

  • @AlbertMartino17
    @AlbertMartino17 Před 4 měsíci +2

    This is incredible. I've never thought to explore derivations of Snell's. These explanations really show the value of animation in education of new concepts, since the hardest part of "understanding" something usually has to do with making some subpar version of these visualizations in your own head... Thanks for all your hard work!

  • @helved807
    @helved807 Před 5 měsíci

    This was actually spectacularly done! It really showed intuitively why all those mechanics work and how they add up to create the system we see. Massive props for you demonstrating the lecture content in a cool way!

  • @berryesseen
    @berryesseen Před 5 měsíci +4

    I hope that no kid was harmed in the making of this video. From the perspective of an electrical engineer, this video was super interesting and explanatory. It's much easier to understand waves and frequencies in this way.

  • @RishabhSharma10225
    @RishabhSharma10225 Před 5 měsíci +3

    Braingasm. Every time I watch a 3B1B video.

  • @MTEXX
    @MTEXX Před 22 dny

    What an amazing deep-dive and clear explanation with immaculate animations. All in 30 minutes???? Wow.

  • @DerProfessor626
    @DerProfessor626 Před 3 měsíci +1

    Bro after my physics studies for becoming a teacher I knew eversthing except for why the light slows down. It was so incredibly well explained and animaded, I will probably use your video to explain this to my students as well! ❤

  • @kolavithonduraski5031
    @kolavithonduraski5031 Před 5 měsíci +3

    25:07 as a civil/structural engineer i appreciate your didactic approach to simplify light movement with springs, the millenium bridge and the swing (mechanical motion).
    I understood almost everything👍😁

  • @user-rm2qj2jh4l
    @user-rm2qj2jh4l Před 5 měsíci +40

    Yay! I've been looking forward to this one! I've been confused about light for a while and I think this video will help me understand!

    • @waelfadlallah8939
      @waelfadlallah8939 Před 5 měsíci

      I am waiting for barber pole effect part 3 pleasssssssssse!

    • @atticuswalker
      @atticuswalker Před 5 měsíci

      finding an excuse you can believe isn't the same as understanding the reason.

    • @MadScientist267
      @MadScientist267 Před 5 měsíci

      This is way overcomplicated and oversimplified all at the same time.
      What happens isn't super intuitive but it isn't really that hard to understand either, but not when the explanation is a series of weird rabbit holes.

    • @VeganSemihCyprus33
      @VeganSemihCyprus33 Před 5 měsíci

      To understand, study... To live in peace, watch this 👉The Connections (2021) [short documentary]💖

  • @erinm9445
    @erinm9445 Před 5 měsíci +2

    Thank you so so much for this incredible series! I have been trying (and failing!) to understand how light could slow down in a material, none of the other explanations made any sense. But your incredible visualizations and clear explanations have finally helped me to understand!

  • @AmitAntony.
    @AmitAntony. Před 20 dny

    I don't usually comment on videos, in general, but this one really blew me away. The animations are brilliant, I watched that Science Clic Video on this subject, and, well, the animations weren't, I'd say, the best. But, these ones are so aesthetically pleasing, it really passes the message through. Excellent job, Grant

  • @santig0_
    @santig0_ Před 5 měsíci +4

    0:50 "hit a wall"... talking about pink floyd... what a awsome choice of words

  • @cookieslammer6411
    @cookieslammer6411 Před 5 měsíci +8

    I can't even explain the amount of joy that I experienced watching this video... Grant, as a third-year physics student I want to tell you, that you job is more than brilliant. Your lessons yet helped me to get through many difficulties on my academic journey. I dream of becoming a physics teacher one day, and your approach to teaching is my main source of inspiration.
    Respectfully, I bow low to you, Mr. Grant.

  • @svmchop
    @svmchop Před měsícem

    I have an undergrad in physics and a masters in engineering. Just watching your animation and listening to your soothing voice reminded me how much I loved learning about stuff. It almost made me cry tears of joy. Godspeed man..

  • @pedrocovolo
    @pedrocovolo Před 8 dny

    what an AMAZING video! Finally after struggling for 4 years in school about this subject i finnaly found interior peace LOL.
    Thank you for amazingly explaining all that, you guys are really doing a good job!

  • @davidyounghans7243
    @davidyounghans7243 Před 5 měsíci +3

    Great explanation, as always. My favorite physics book, Thinking Physics by Lewis Epstein, uses the metaphor of a man running into the ocean at an angle to explain why (and how) light refracts when it enters a slower medium. A picture would be a lot better here, but, to take the least time to get from point A (on land) to point B (in water), the man runs along the beach longer than if the entire path were straight, then turns at close to the last second before entering the water. If light takes the least-time path from point A to point B, it follows a similar path.

  • @9darkspells
    @9darkspells Před 5 měsíci +12

    This along side the recent videos by Huygens Optics have added so much to my understanding of wave propagation

  • @mcv2178
    @mcv2178 Před 5 měsíci

    THANK YOU! About a year ago I got curious and tried SO hard to find this out! I was not even sure how to ask what I wanted, and got nowhere, and gave up, and now you have given me what wanted to know, without even being asked : )

  • @thecomputerscientist209

    Amazingly explained. All hands down. This explanation works with one photon at a time as well, as the wave function interacts with everything producing the same result.

  • @lazarussevy2777
    @lazarussevy2777 Před 5 měsíci +4

    Good timing! I'm going into optics in my physics class just about now!

  • @landonkryger
    @landonkryger Před 5 měsíci +3

    I look forward to your video about the index of refraction being < 1. I hope you also cover the rare case where the index of refraction is negative.

  • @manuel_ao
    @manuel_ao Před 5 měsíci

    Thank you Grant for such a thoughtful and well-animated video and thanks to Richard Feynman for all the intuitive answers that he has provided to so many physicists. I will re-watch videos 1 - 3 again but I would love a video that wraps up everything to explain the barber pole animation.

  • @SilverwingVFX
    @SilverwingVFX Před 5 měsíci

    Wow. Again I Have to express how well made your videos are. Its amazing how much finesse those animations have!
    I am super glad this exists. I will definitely use it in my shading classes for 3D Artists. Its always good to dive deeper and your videos are the gold standard for this!

  • @FoughtAgaisntSisera
    @FoughtAgaisntSisera Před 5 měsíci +6

    This video is amazing! I wonder if you might touch on Hamiltonian physics applied to ray optics and how that connects to the principles described here

  • @roshini723
    @roshini723 Před 5 měsíci +3

    I'm a physicist and your videos are helpful when I try to understand mathematical concepts visually. Could you also make a video on Surface Plasmon Effect? I would say it fits perfectly to your series you're currently making on optics.

  • @pedrocovolo
    @pedrocovolo Před 8 dny

    i had always been the implicant guy in physics lectures in my high school until i found the explanation for current flow from veritasium and this optics crazy matter.
    they are really making a good job in international youtube

  • @PluetoeInc.
    @PluetoeInc. Před 5 měsíci

    This is the most important youtube video in history , by units of value , if we define value by 2 independent factors P (popularity) = view count and S.q (satisfaction quotient) and therefore if value V is defined by V= P * Sq , I am practically having a mindgasm with all of this compressed in one video , I waited so long for these and I didn't even know it myself , Thank you grant , Thanks a lot , you have single handedly changed the course of human history .

  • @Youtubehastoomanyads
    @Youtubehastoomanyads Před 5 měsíci +20

    Hey! You are the reason I love maths so much thank you, for such amazing videos.

    • @waelfadlallah8939
      @waelfadlallah8939 Před 5 měsíci

      I am waiting for barber pole effect part 3 pleasssssssssse!

    • @gw6667
      @gw6667 Před 5 měsíci

      *math

    • @iqwit
      @iqwit Před 5 měsíci

      ​@@gw6667not everyone is American my guy

  • @WarzoneMasters
    @WarzoneMasters Před 5 měsíci +6

    i learned so so much with your videos respect forever ♾️

    • @waelfadlallah8939
      @waelfadlallah8939 Před 5 měsíci

      I am waiting for barber pole effect part 3 pleasssssssssse!

  • @fdert
    @fdert Před 5 měsíci +1

    You just earned yourself a new subscriber. I'm very impressed with how you explained the additions of waves with use of vectors, by far the best explaination of this phenomenon I've seen yet.

  • @beemerwt4185
    @beemerwt4185 Před 5 měsíci +1

    6-ish months ago, I had to learn a lot of this because I was working on a game, and the math about waves hit me... like a wave... as it's all coming back to me. I like the way you explain it, especially with the vector visualization. Picturing this in my head I use the words but actually seeing you graph a vector was fascinating. A lot of the math I know nowadays from programming videogames comes from my AP High School classes, but we never touched on vectors so I have since taught myself. I guess that was more of a Linear Algebra thing (which wasn't offered at my school), rather than Calculus and Trigonometry (which is what I took).

  • @Codexionyx101
    @Codexionyx101 Před 5 měsíci +6

    People like to say that light slows down in a medium because it "bounces off" the particles in the medium. Kyle Hill refuted that in one of his videos, but didn't really describe exactly what's happening. This finally explains what he was talking about.

  • @890sigma
    @890sigma Před 5 měsíci +20

    Love the vid! Could you also cover Maxwell’s equations in a video?

    • @gw6667
      @gw6667 Před 5 měsíci

      This is not an intro to electricity and magnetism class. Plenty of resources on CZcams to dive in. What do you want him to do, derived the equations?

    • @890sigma
      @890sigma Před 5 měsíci

      ​@@gw6667I just want a video that shows the visual intuition behind maxwell's equations in a way that feels intuitive and makes sense

    • @GaussianEntity
      @GaussianEntity Před 5 měsíci

      ​​@@890sigmaThe four equations are basically the four main laws of electromagnetism. The propagations described in this video is one of them, Faraday's law of induction.
      You may find visual representations if you search for them separately.

  • @patrickmuller3248
    @patrickmuller3248 Před 3 měsíci

    That is a FANTASTIC video. You give an explanation AND give further explanations to those. That is genius! One of the best ways to describe what is happening I have seen to date.

  • @MeepMu
    @MeepMu Před 5 měsíci +2

    I've been studying vibration for this past week and messing around with these equations, so a lot of this is very recognizable at the moment. What a nice coincidence that this video comes out now, as it's answering a few questions I've been having 😅

  • @weksauce
    @weksauce Před 5 měsíci +3

    Murmurs to self: This isn't how mom does it.

  • @jaroel
    @jaroel Před 5 měsíci +5

    22:23: thats why "mom" can't teach you about prisms

  • @rayoflight62
    @rayoflight62 Před 5 měsíci +1

    The sum of the two sine waves is exactly the same we use to calculate the sea tides; two waves are representing - respectively - the effects of the Moon and the Sun on the height of water.
    Thank you for the video
    Anthony

  • @SC-rb2jr
    @SC-rb2jr Před 3 měsíci

    This video is shocking. It takes a difficult topic and with a calm clear explanation and superb graphics, it actually makes it understandable. This is the ultimate in education excellence. Please make these videos known to everyone that wants to learn about physics.

  • @capitaopacoca8454
    @capitaopacoca8454 Před 5 měsíci +3

    Since temperature is the wiggling of particles, doesn't temperature affect this? Or it's a random wriggle so its effects cancel out?

    • @MaxIV77
      @MaxIV77 Před 5 měsíci

      Not an informed response. But I would think it can largely be separated from the math he is doing in the video. Unless you are getting to temperatures where the integrity of the bonds of the material are being messed with (think melting or changing density) I would think you could treat the electric fields as a superposition of whatever equations you come up with.

  • @VJfication
    @VJfication Před 5 měsíci +6

    Me gently murmuring: "that's not how my teacher explained things". 😂

  • @helmutalexanderrubiowilson6835
    @helmutalexanderrubiowilson6835 Před 5 měsíci +1

    I am 42 years old I have been stuyding electromagnetic waves for 20 years and teaching Wireless and optical applications for around 12 years. I feel safe to say that you are one of best - if not the best professor of the planet. The The amount of work you put in your explanations is unprecedented.. as you show in your videos there are some excellent professors around there but none of them with the skills to represent the content in this way. Thank you I'm fan of you great work!! I think you should publish some books using your skills explainning the topics you present here... They would be global betsellers for sure.

  • @JordanMcCaughey
    @JordanMcCaughey Před 5 měsíci

    Just in time for my advanced electromagnetism exam. This is a great video, exactly the visualisations the topic needs! I hadn't grasped how the phase "kick-back" was at every point in the material but your visualisation has totally cleared it up!

  • @lucasthompson1650
    @lucasthompson1650 Před 5 měsíci +11

    I clicked on this video thinking it was a Pink Floyd thing...

    • @michaelstanley1326
      @michaelstanley1326 Před 12 dny +1

      then you ended just as happy

    • @lucasthompson1650
      @lucasthompson1650 Před 12 dny

      @@michaelstanley1326 Probably a little happier, actually, I think. Or at least, I don’t know anyone who’s ever locked themselves in their room and spent 24 hours engaged in optics puzzles after a harsh breakup.

  • @gabrielhamrle2779
    @gabrielhamrle2779 Před 5 měsíci +3

    3Blue1Brown started creating physics viedoes so that we would study something useful and not pure mathematics.

  • @Elfstones3n1
    @Elfstones3n1 Před 4 měsíci +1

    As a former math & science teacher, this video is one of my favorites ever! Some parts were intuitive; other parts weren't; other parts I was figuring out a minute before you addressed them; all of it was SO INTERESTING!!! (Also, I loved the illustration with you pushing your niece on the swing!)

  • @baptistegroussin5019
    @baptistegroussin5019 Před 3 měsíci

    From a laser physicist’s standpoint : this video is so, so good. Brilliantly made, congrats. There is room here to explain all of a nonlinear optics !! Would be awesome that you do a bonus video for nerds on that topic !

  • @shikhanshu
    @shikhanshu Před 5 měsíci

    The level of detail is staggering in these videos... one of the most important youtubers out there

  • @davidwilkie9551
    @davidwilkie9551 Před 5 měsíci

    Saved this video for ages, because it's making the back of my neck tense in anticipation of how beautifully it illuminates the story of assembly for the e-Pi-i holography dimensionality coordination sequences.
    And I still think Feynman knew what Wheeler's One Electron Theory was about, but being an expert Teacher, kept it within reach of his Students.

  • @atil4
    @atil4 Před 5 měsíci +1

    A lot of physics and math Extremely well explained, and compressed in 29m. Please more!

  • @user-id5ik6lq6m
    @user-id5ik6lq6m Před 7 dny

    WOW it is so... Pleasant? I don't know. I'm learning English & you were my first channel to watch on some sustainable basis. I'm so glad I'm here. Thank you!

  • @davidhjortshoej4774
    @davidhjortshoej4774 Před 5 měsíci

    The animations are always so satisfying. Goes right to the heart of a visual thinker

  • @RobinWootton
    @RobinWootton Před 4 měsíci

    Amazing how you churn these out. This would be more than a lifetime's work for some of us!

  • @jonahansen
    @jonahansen Před 5 měsíci +1

    Dude - you do such an excellent job here. I created a playlist about index of refraction, and you cover it all, and with the correct and quantitative explanation for every aspect of it.

  • @linearj2951
    @linearj2951 Před 24 dny

    Everything about this video was awesome, but the part that stood out to me was your characterization of "handed-down vs discovered." This is a great way to express my frustration with getting answers to some questions. I ask "Why/How" (discovery), but instead get "What" (handed-down).
    One question I have had forever like this is: why do mediums block waves with wavelengths shorter than the medium thickness? E.g., why does bass get through a wall, but treble is blocked? I always get the answer that "of course, because treble is higher frequency, and thus shorter wavelength. If shorter than the thickness, it is blocked." But... WHY? That is a handed-down answer; I want a discovery answer!

  • @jayakrushnasahoo4403
    @jayakrushnasahoo4403 Před 5 měsíci

    INCREDIBLE. Finally got a satisfactory explanation after longtime wondering about it. Keep the curiosity alive, it will sustain the science and the civilization.

  • @sploofmcsterra4786
    @sploofmcsterra4786 Před 5 měsíci

    4:05, 9:01 As a Physics researcher, I'd say these are the best animated demonstrations of atomic dynamics leading to near and far field behaviour I've ever seen. It is very difficult to create good illustrations for electrodynamics, but sorely needed!

  • @YanivGorali
    @YanivGorali Před 5 měsíci

    This channel is a treasure that keeps on giving

  • @deneshk353
    @deneshk353 Před 5 měsíci

    One of the best 30min spent!
    probably the cleanest and neatest to the point explanation! Thank @3Blue1Brown for doing this...

  • @moltenguava9418
    @moltenguava9418 Před 3 měsíci

    I've been watching your videos for around 5 years. They inspired me to pursue my major. I have now graduated. I rarely see channels continue to make such good content consistently for over half a decade. Thank you.