Yes, these videos are gems. Nice to see the new ones appearing and the view/subscriber count going up too ... might persuade _Physics Explained_ to keep making them.
I love the level of details you dig in your videos. Being an associate professor of physics myself I have listened, read and taught this many times. But the "enhanced intensity of rays" around max. angle nuance has always escaped my attention. Thank you for the quality work and keep it up! Best regards from Turkey...
Best physics channel I’ve ever seen. Lots of channels avoid any maths fearing to lose viewers ; others do not refer to the history explaining how theories were developed. And just these elements are necessary for understanding. And understanding increases the mind and brings joy. Thanks.
The obligatory quote: "...the science knowledge only adds to the excitement, the mystery and the awe... It only adds. I don't understand how it subtracts.” ― Richard P. Feynman,
This is technical knowledge with a whole lot assumptions and presuppositions lacking any sort of context of time and space of real life . Science is knowledge that stands the test of time and this is not it as technical knowledge is always changeable. You are just confusing technology and science as almost everyone does and perverting science in the process.
@@gledatelj1979 This is the only explanation of the rainbow that ever stood the test of time (or any other test, for that matter). This is science and technological applications are not even discussed. Before you come lecturing others on things you are incompetent of, learn to use punctuation and to write complete sentences.
I appreciate that you take time to explain the subject in a deeper manner but still targeted for laymen like myself. There's not that many channels like yours in youtube
Starting a degree in physics soon (October) I must say I love your well made, articulated and presented videos. Especially how you show the maths, equations and thought processes for proofs; certainly helps me stay sharp in my physical intuition.
Thanks for taking the time to leave a comment. My aim when making these videos was that a bright high school student should be able to follow the logic and the mathematics. Too often the mathematics is omitted at school, and yet often (for me at least) it helps with the understanding. I am really pleased that you find the videos helpful and I wish you the best of luck in your physics degree!
@hugh mungous, agree, the maths is really important. Otherwise it becomes what I call "glossy science", which I read for years and never felt satisfied until I finally started studying physics formally. Good luck with your studies and hope you find it as rewarding as I did.
i really envy you, i studied physics 20 years ago, one of my brothers work at CERN projects and I decided to move to software engineering, but my heart always bring me back to physics videos lol. I want to share with you something I learn during my career, the really most important part is hard work, you will meet lot of smart people, some of them extremely smart, but those who will be successful are those who work harder than others, at the end hard work and constant will define who is really great. never ever stop attacking problems, even if they seems impossible at some point, just continue learning and attacking again, good luck.
After watching this stunning presentation, I am reminded of Richard Feynman's comments regarding a scientist's perception of beauty in nature. "An artist friend holds up a flower and says, 'Look how beautiful it is,' and I agree. Then he says, 'I as an artist can see how beautiful this is but you as a scientist will take this all apart and it becomes a dull thing'... Although I may not be quite as refined aesthetically as he is... I see much more about the flower than he sees... beauty at smaller dimensions, the inner structure, also the processes... It only adds. I don't understand how it subtracts." (Richard Feynman)
We had intense rainbow here yesterday and as a scientist I was asked to explain it. I did my best and got maybe 3/4ths of this explanation, but this video explained the whole thing really well and helps me understand the details I was missing. Really well done, congrats.
Thanks for great videos! I don't know if it matters to you... but when someone asked you to drop ads, you agreed for some reason and left only one slot. I believe you deserve more following and a bit more ads is the least we can do to support your work. Those who don't want to watch ads can always buy youtube subscription and enjoy the ads-free experience.
A truly enjoyable channel on RU-vid ... I point these lectures out to my son ... hoping enough is understood, that he would study more out of interest. Thank you ...
I think some cases of physics remove the beauty of perceived reality. Like when Steve Mould and the laser guy were looking at a laser interacting with a soap bubble, and it occasionally showered the room with hundreds of little dots. After some careful examination, they deduced that it was caused by the disco ball on the ceiling. Jokes aside, nice explanation! I think I’d be interested in seeing a graph or at least equation that predicted the spectral radiant intensity at a given angle, to see how much each colour dominated. Because technically the Sun’s light is dominated by green light, but our eyes see it as white because it’s a broad peak. Though it’s probably just got an f(solar black body) multiplied in front of the equation in the first place.
Thank you for this accurate description. Far too often, when rainbows are explained for non-physicists, it goes beyond being just inaccurate. It actually teaches some of the underlying concepts incorrectly. The most egregious might be that the bright bands occur due to Total Internal Reflection occurring at just one angle. With no reflection occurring at other angles. The truth is that, at every encounter with the water/air boundary, a small fraction of the light is reflected while the rest transmits. Here is the non-physics explanation that I like to use (all numbers are approximate): 1) Rainbows are created by all of the light hitting a raindrop, not just light at one spot. So any explanation that draw just one ray of incoming sunlight is already inaccurate. 2) The drop reflects this light back toward the sun in a ~40° wide (from the center) beam, much like the mirror in a car's headlight or a flashlight/torch. 3) But there are two significant differences: 3A) The width of the beam varies with the color of light, extending out to 42° for red. 3B) Each color is much, much brighter in the outer 0.5° of its range. 4) This places the bright-red part of the beam between 41.5° and 42°, with (essentially) no other colors of light in that range. So we see a bright red band of color there. 5A) The bright orange band is between 41.25° and 41.75°. Half of it overlaps the red band, but there is some red under all of it. 5B) The bright yellow band is between 41° and 41.5°. Some overlaps the orange band, but there is red and yellow light under all of it. 5C) This continues, making each color toward the end of ROYGBIV appear paler that the same color in a spectrum, until we reach white light inside the violet band. For double rainbows: 7) Because there are two reflections, the beam is reflects _away_ from the sun, and is ~130° wide. 8) The red band is still on the "outside" of this beam, and the overlapping occurs the same way. But because the width is more then 90°, the beam wraps around the top of the sky and is seen - _upside_ _down,_ not reversed - about 10° above the primary rainbow.
Thank you the great explanation. I had an entire section of an assignment based around this topic. I have yet to find in depth explanations like yours, and i really hope you will keep making these videos!
A very good balance bwtween the necessary mathemaical complexity and the simplicity of physica of rainbow formation. This video not only sufficiently explains the process of rainbow formation for a highschool grader but also provides clues for deeper studies into this topic. Great job!!!
....and now I know!! Except for the math bits, that just gave me a headache but the clear explanation of the 'production' of a rainbow was great!.... Now to wait outside until there is a rainbow & my neighbours come out & are all, "Ooooh!" & "Aaaah!" & I can say..."I know why that happens!"
Thanks for the feedback, glad you got something out of it
3 года назад
It would be nice to see the picture of the rainbow through red and blue filters, and the plot of intensity of the light for different wavelengths versus the rainbow angle.
Does this mean there are more rainbows at greater angles that just get too faint to see as the reflections get less and less likely? Or is there a reason our idealized raindrop can only reflect twice? This was a surprisingly interesting video! It made me think of the chapter The origin of the refractive index in the Feynman Lectures and the Corpuscles of Light talks.
I've definitely seen triple rainbows. I reckon the intensity is just too low to perceive any more than that, though I can't say if there's another physical reason related to the geometry of the water drops.
Excellent video thanks! Could you expand it slightly to cover the change of curvature of the rainbow and why pilots remark that it is possible to fly through the bow as if it is a circle. As we are all addicted to animations now a video showing changing observer position would be very interesting. Thumbs up and subscribed.
This is the best explanation I’ve ever seen on how rainbows are formed and why there is a secondary rainbow. I would like to ask the question, however, why, when observing a rainbow from an aircraft looking down on clouds, the rainbow angle is significantly smaller than 42 deg?
You're right, those aircraft "glories" are less than 20 degrees angular width. Apparently they are formed in a much more complicated way than regular rainbows, and the details were only worked out in the 1970s. That's according to this web reference, but I couldn't find anything further: web.archive.org/web/20070814050142/www.polarization.com/rainbow/rainbow2.html
@@incription , hey, don't apologise, we're all goofing our way to a better understanding... including the physicists themselves. One of _Physics Explained's_ other great videos on the Ultraviolet Catastrophe led me to a whole weekend of researching the tortuous history behind that idea. The physics books can leave you with a misleading idea that every idea arose fully formed in the mind of a genius, but the real history is always a messy case of many minds groping toward an eventual explanation. I really like that _Physics Explained_ provides a potted history as well as the science.
This was just the right amount of info needed to make this info understandable, great work!! My question is,can the primary and the secondary rainbows be reversed?if yes,would the "alexanders band" actually appear to be a brighter area?
hello, i can see you have a lot of followers who love your content, that is so cool, specially as you help to spread knowledge in physics. Can you do a video about double slit experiment and the quantum eraser? for me is extremely fascinating.
I have never noticed the difference in intensity in the region above and below the rainbow before, until after watching this video. How have I never noticed it before in my life?
Here is what I was hoping this video would explain but didn't, and if it did and I missed it I apologized: Why do I see one rainbow instead of a trillion little ones? I'm still unclear how I see 1 giant rainbow from a collection of droplets. Are the droplets close enough that they act like 1 giant drop? I appreciate the content and subscribed. Thanks and keep the great content coming!
Absolutely prophetic description of rainbows!.. one important thing I feel you missed though is a detailed explanation as to why it's shaped like a bow. 😢
@@kirkhamandy I'd just have liked to see more detail about it in the video. Given the deapth he went into I kinda feel somewhat cheated out of the 'bow' in rainbow with only that brief description. I should probably add, though admittedly not to the degree given in the video, I do know how rainbows work.
If the speed of light really is constant then we'd never see a rainbow at all, would we? If it can't be slowed down [or sped up] then the various frequencies could never be separated from each other. That's what I'm getting from this video. My first question was "but how can light 'slow down' if it is a constant?"
Thanks for taking the time to leave a comment. As you correctly say, the speed of light in a vacuum is constant. What causes the light to 'slow down' is actually due to the interaction between the light and the electrons inside the water. For a fantastic explanation of what is really going on, I would suggest watching this old (but classic) video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-R8nRfs7JCOI.html
Awesome ! Thank you ! I knew only the basics of the rainbow so this is really nice. I also knew that prismatic effects like this separate the colors but never thought about the refractive index changing with frequency. WHY is that ? I mean, is the permittivity and/or permeability of the medium (in this case, water) different for different frequencies ? I usually think of these two characteristics for speed of light or electromagnetic radiation in a vacuum. Or is it due to something else in a medium like water, glass, etc ? Maybe this should be obvious or not.
Thanks for the kind words. Regarding your question relating to refractive index, I would recommend watching the following fantastic video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-R8nRfs7JCOI.html
Reminds me of this bestseller popular science book called "Unweaving the rainbow" by british intellectual and evolutionary biologist professor Richard Dawkins
great video, I have a couple questions: Why does it make a circle? And why is it not a straight line of red, blue, etc across the sky at particular angles?
The diagram at 5:00 shows that. Since all positions are fixed (the sun, the idealized droplet and observer), there's only one path that will make it all the way from the sun to your eye, where the incoming and outgoing beta angles are equal. And since beta is treated as a variable, it can take on any value in the range [0,90] degrees (if you want [-90,0] just flip the diagram.. its symmetric along that axis). And of course you can extend the argument to a perfectly spherical idealized droplet in 3D by just slicing along the plane that contains the sun, droplet and yourself since light rays can be treated as one-dimensional beams in the context of classical mechanics (until suddenly they can't.. and then you need quantum mechanics to sort the mess out but that's well beyond necessity for understanding "simple" reflection and refraction).
Hey, could you please explain the calculus part a bit better? How does that expression at 8:40 come up? I haven't taken calculus yet but I'm curious to know
I've watched most of the videos now and I think they are impressive in explaining in laymans terms some really complicate sh^H^H stuff. The delivery is good, but the varying volume distracting, could the audio be normalised? Oh, and please, please, keep up the good work!
This is such brilliance! Why on earth aren’t we examined on these kinds of things in school, rather than doing 10000 iterations of Young’s double slit experiment…
Whats the frequency of invisible light (em radiation) that emerges exactly halfway between the primary and secondary rainbows, and does this frequency carry any significance? Great video, thank you!
rain drops or other suitable water aerosol drops are not circles, nor spheres, so dont get hung up on specific angles being realistic. it does though show some of the beauty of science.
Hi! Thanks for posting these interesting videos. I hope you not offended by my asking what your background is. The material you present is beyond my current level of understanding, hence I can't determine if what your teaching is incomplete and would appreciate to know what your credentials are. I hope you agree that this is a reasonable question and understand that I'm not 'trolling' in anyway by asking. Thanks in advance
