You know, when i first saw this channel i thought it was gonna be a boring one w/boring people talking in a boring fashion difficult for most to hold on to w/no passion, like allot of these programs are, but everyone here is always so passionate and exited and explain things in such a meaningful way that's easier to understand. I love it and think this is what we need more of. Keep up the great job! 👍
Thanks for this. I agree that understanding something "beautiful" actually adds to the experience rather than ruins it. I think the night sky is a very good example of that!
Very well thought out explaination. I've long known that rainbows were caused by reflections in the droplets, but had never really wrapped my head around how exactly, even through I'm pretty good at physics. This video just explained it so well. Keep 'em coming, Brady
at the final, 6 :30 , it sounds like a R. feynmann quote "science knowledge only adds to the excitement and mystery and the awe of a flower. It only adds. I don't understand how it subtracts." nice video congrats sixty symbols
The exact same thing as described in the video. Due to the angles that make the reflection work, a rainbow is always a circle, and if you could somehow see your own shadow when looking at it, it would always be in the center because the sun is always precisely behind your back when facing a rainbow. Earlier this summer, I was fortunate to spot a rainbow caused by a sun that hadn't even risen. Huge, round and high up in the still slightly dark sky, thanks to the sun being so low. Wonderful.
Thank you Thank you Thank you! I've read explanations before, and they've always left me feelings frustrated, and without a FULL explanation. This has given me the FULL picture!
It's simply a third internal reflection in the rain drops. Each time light encounters an interface with a different refractive index (the interface between the water inside the droplet and the air outside) under a steep enough angle, you get part of the light being refracting (i.e. passing through the interface) and part reflected. It's kind of like a round semi-transparent mirror. The light can bounce around in the droplet quite a few times, but each bounce attenuates it significantly.
When Prof. Merrifield, began speaking about beauty platonic and intimate(technical) beauty, I was immediately reminded of a conversation Richard Feynman once had with an artist. It's quite poetic how the father of quantum electrodynamics and this seemingly unrelated thought are intertwined. Feynman's Rainbow~ :D
I have to agree with you on that. It would be like saying that studying botany or horticulture diminishes the beauty of a garden, when (in my opinion) the opposite is true. If you were to walk through a garden with a botanist/horticulturalist, I'm sure that they would see and appreciate the same beauty as you (as well as picking up on several things that you probably didn't know/notice).
I really enjoyed seeing at least ten vertical rainbows in Iceland during the Midnight Sun. It was around midnight, too. Very pretty, partial rainbows. I live outside Paris, France and know of a place where you can almost always see full rainbows if there is the slightest weather change. It's so cool!
I agree, understanding how something works doesn't ruin its aesthetic value, it actually enhances it. If you admire the beauty of something so much, don't you want to know what makes it so beautiful?
Having read Walter Lewin's "For the Love of Physics", which contains a whole chapter about rainbow physics, I appreciate rainbows only more. One day, when I went to Wageningen to check out the university, it was somewhat rainy all day but not particularly cloudy, perfect rainbow weather. So I faced the sun, turned around, looked at my shadow, turned 42 degrees, and there it was: a perfect rainbow, with another one around it. In the early evening waiting for the bus I got to see another double.
You're correct. Inside the violet arc is an ultra-violet arc - porbably visible to bees. They can see UV. Outside the red arc is a very, very faint infra-red arc. Theoretically visible to night-vision goggles... although you'd be blinded by the brightness of the rest of the rainbow if you put them on!
For the last part, there are always the people who need to not know how things work to appreciate them, and people like us who grow a deeper appreciation knowing how things work. It applies to favorite movies and magicians' tricks, for examples that science lovers might better see why a lot of people are disappointed to know the facts. Learning the truth about "the smell of rain" both killed the romantic aspect and gave me clarity about why it always smelled earthy rather than like water vapor.
The secondary rainbow is at 50°-53°, the primary between 40° and 42° (42° is for red, 40° is for blue). There are ternary rainbows, but they're very rare because they are so faint. While for primary and secondary rainbows the light is reflected back, for ternary the 3 reflections make the light go the same direction as it entered. That's why you'll see ternary rainbows in the direction of the sun, instead of the opposite direction.
Don't forget to mention Al Hacen who first correctly described the phenomena of the rainbow. He also came up with the perplexing "2 points in a circle" geometric construction problem.
If you'd show any scientist a bus that goes through the air, I can assure you that they'll be blown away. Anyway, it is magical if you understand it, you can look at the way the wings work, how they keep a 187,700 pound plane from falling; you could look at the way we managed to control those wings, the electrical circuits, the controls that the pilots have in their hands, or in the reach of their hands; you could look at the amount of gas each one needs to stay in flight and be astonished.
Yes. The photons are being absorbed by ground state electrons of atoms that the photon contacts, which causes a delay, and then the photon is re-emitted as excited electron decays back to its lower energy molecular orbital. The photon then travels to the next atom's electron within the medium at the speed of light. All this interaction causes deviations in an ideal straight path, the increases the total distance traveled proportional to the time passed, keeping the speed constant.
People who say that understanding how something works makes it less beautiful drive me crazy. I think you must have a very limited imagination if you need something to be "magical" (i.e., beyond comprehension) to be amazing. (Nevermind that the physics are true, whether or not you're paying attention.) I really enjoyed this video!
Dear Sixty Symbols, can you please have these professors explain in their wonderfully round way the issues relating to the Earth's climate in a series of videos? Their insight is needed.
It's not the "total" distance / time that decreases. That remains constant. The straight line from A to B through a medium (without taking into consideration the distance light has traveled in all other directions) distance / time does decrease.
Common misconception. The leprechaun is in the middle of the circle. Do you have to go up in a plane to see him. And, since he's on the ground, you can't catch him from up there. I mean, that's just science
What you saw is a somewhat more complex optical effect called "the glory" or the "Brocken Spectre". There are plenty of videos of the effect here on youtube.
Regarding that question at the end, my personal response to that is: . The things that are truly amazing things are the ones that continue to be amazing after you understand them.
1. The sun might not always be able to hit the rain with enough intensity to cause a rainbow. 2. Heavy rain, such as would produce a vivid, memorable rainbow usually occurs in the afternoon and evening with showers and thunderstorms, if you are in the United States, storms most often move west to east and usually have dry air behind them, either as part of the storm or a larger air mass. This clears the air of clouds and lighter rain behind the heavy rain, allowing the sunlight in.
It is actually not "bouncing" that causes light to slow down in a medium, but the absorbtion of light by atoms and the time it takes them to re-radiate the light again. And as as far as the explanation for the refraction goes. You could compare it with a man in a wheelchair reaching a plane coated in honey at an angle. First one of his wheels will slow down while the other will continue at normal speeds and this will cause the wheelchair to turn.
Interesting video! This is an invitation to see an artist theory on the physics of light and time! This theory is based on just two postulates 1. Is that the quantum wave particle function Ψ or probability function represents the forward passage of time itself 2. Is that Heisenberg’s Uncertainty Principle ∆×∆p×≥h/4π that is formed by the w-function is the same uncertainty we have with any future event within our own ref-frame that we can interact with turning the possible into the actual!
You probably saw an ice halo instead of a rainbow. Look up "atmospheric optics" and then click on the ice halos section and you'll get a very good explanation and some very pretty photos as well.
Yes it is. In order to see the colored light you have to look in a certain angle at the raindrops, resulting in a cone starting at your eye where raindrops are in the right position, that's the circle you see. But this was talked about in the video, so I don't get how you cannot get this.
Re-read my comment... the speed of light (denoted by the constant 'C' as used in E=MC²) is CONSTANT, when going through a medium such as water it still moves at the speed of light (the same as in a vacuum) but it bounces around a lot more and therefore it takes longer for it to travel in a straight line from point A to point B. It bounces around but it still moves at the speed of light.
I once saw a circular rainbow around a full (or very nearly so) moon. The effect was very clear and the spectrum(?) of colours was restricted to blue, indigo (is that still a valid colour name?) & violet. It was very beautiful. Ps. Enjoyed the video very much, thank you for your continuing efforts.
An evening, during a landing in an airplane, we descended into a slightly transparent cloud. I witnessed two fully circular rainbows, with the shadow of the plane dropping in the middle of it... Single most amazing thing I've seen in my life.
I see those all the time when I'm on the ski slopes in winter. The halo is then caused by tiny ice crystals in the air. The crystals refract the light the way raindrops do. The dispersion in ice is greater than in water, that's why the colored band you see is wider (and fainter) than a rainbow.
Yes, this is actually how infrared and ultraviolet were discovered, via an artificial rainbow made with a prism. Look up William Herschel for the discovery of infrared and Johann Ritter for ultraviolet. They used two different methods of detecting the light, both are pretty clever.
Understanding things makes one appreciate them less? On the contrary I never cared for sunsets or rainbows at all until I understood what caused them. Now I can sit and stare at them for ages admiring not only the innate beauty but also the beauty of the physics as well.
It is a common misunderstanding that the colors in the secondary rainbow are reversed. The are actually upside down. The difference is subtle, but true. Technically, red is on the _outside_ of both rainbows, but in the secondary outside is _down._ The white part mentioned at 3:30 is not just a small area. It actually goes all the way to the center of the rainbow; well, if there are raindrops there. In the primary rainbow, it is at the shadow of your head. Think about the light that hits the drop right in the center, bounces straight back, and exits. This is the center of the primary rainbow. For the secondary this light reflects twice, and exits the raindrop in the exact same direction as the original ray of sunlight. So the "center" of the secondary is on the sun itself. But the rainbow itself is about 130 degrees wide. It fills the "sun side" of the sky, wraps around the top, and is seen upside down about 50 degrees from the shadow of your head. No, you don't see a third rainbow this way. I'm not saying that it can;t occur, but it would be seen on the sun-side of the sky. Same with the fourth order. They have been photographed, but are very dim to the naked eye.
Because the distance between the point of refraction, and the point where you pick up the light (the retina) has a big influence. The farther the light travels after being refracted, the more it gets dispersed. So it does indeed undergo dispersion in our eyes, just doesn't get spread enough out to be noticable.
Theoretically this is possible... kind of. But almost definitely not in the way you're imagining it! Watch sixtysymbols video on Young's Double Slit (I'm just assuming there is one!)
Imagine that the point you are looking at is at 0 degrees, if you look straight to your left, your right, up or down you are looking in 90 degrees from your original viewpoint. at angles of 42 degrees you will see the light (which is coming from behind you, otherwise you don't get a rainbow) reflected back to you. That 42 degrees can be anywhere to the left/right or up/down or a combination of them like up to the left. If you are up in the air with the sun behind you then you get a full circle.
I've seen a picture of a full circle rainbow online somewhere, I believe it was taken at a waterfall. Very cool. I believe to that the 'Gold at the end of a rainbow' thing was a kind of inside joke with the Irish or whoever because they understood they were a circle and had no end =). Science and Historic humor ftw.
Love Sixty Symbols, I could listen to all the professors all day! I only got Science double award in secondary school but seem to have carried on my learning experience after school with self study. I usually read about Evolutionary Biology and Ecology which I really do love. But I've been sucked into Quantum Mechanics over the past few months as the Quantum world is so bloody interesting. Thanks for the great Channel best regards from the locals at Kirk Hallam (just down the road) :P
Thanks for the tip. What I meant when I asked was not there, unfortunately. Once I saw someone asking why does the speed of light changes when it goes from one medium to another, when light speed should be a constant, and the answer was that, in fact, the speed is always the same, but in a more refringent medium it bounces back and forth, taking more time to cover the same linear distance (that's what I mean by microscopic explanation). I'm still not clear on why it changes angle though.
Well, if you have a very long arm, it should be possible to place your hand between the droplets responsible for the point where the rainbow meets the ground, as seen from the location of your eyes. Or you could place some device which could detect (and grab) pots of gold, and place it at a given point (a point with droplets, surely), then calculate where you need to place your eyes in order to have that specific point with the "Pots-o-Goldiator" be the right one.
no ,no. im saying that the reason the colors bend at different angles are due to the wavelengths of light. this has to do with conservation of momentum and energy, so because light slows down when entering water from air, the phase angle must change to keep the frequency constant. and since blue light has a longer wavelength, the phase angle change is larger (thus more bent) than that of red light. (also i made a small mistake in the other comment, frequency =/= wavelength). hopefully that helps
things (planes, birds and the universe) are complicated. every solved mystery raises even more new ones usually. more magical stuff to ponder. it explains why scientists are not the most bored by the universe but the instead the ones who find it most fascinating.
Different materials bend light differently. If you shine light upward from underwater to air, it'll go straight through, but at 45 degree, the light'll come out at a smaller angle say 30 degree. So you can imagine that if you tilt the light more, to say 15 degree, then it'll come out exactly parallel to the surface of the water--or get bent so much it can't escape and reflects instead.
Nice! When he just explained, that the colors of the second rainbow are reversed because of the second reflection, I went " Ohh, this is so cool!" Man, I love science!
The "speed" (total distance/time) is still the speed of light while the "velocity" (displacement; depends on two points of final and initial; final position - initial position / time) is slower because the denominator, time, increased while the "displacement" for both un-refracted and refracted light rays remained the same.
Your all awesome! I knew the answer but I still end up understanding it even further. I love learning in such an enjoyable way. This and your double vision are superb vids
Circular pattern: suppose the sun rays are horizontal. All the raindrops will create rainbows in a 42° cone with the sunray as axis. Most of these will miss your eye. The ones you'll see are the ones where your eye is on that cone. That cone is a full 360° so if the drop is below you at 42° you'll also see the spectrum. So when you're up in the sky the rainbow will become a full circle, caused by all the raindrops which create a 42° angle between you and the sun.
No. A flashlight literally creates photons when it shines. An electric current heats the filament. As the filament heats, the electrons in it become excited and start wiggling. When electrons wiggle, they send off packets of energy in the form of electromagnetic radiation (aka light). So yeah, it does "just convert energy from one form to another," but light is basically just a way to move energy around. Besides, where else do you suppose the light comes from?
i agree, it does add to the beauty, understanding something takes nothing away, i dont need to believe something is "magic" to see it as beautiful. I wish some people didnt think that way.
Rainbows are centered around the antisolar point, which is a point directly opposite of the sun. If the sun is halfway up the sky in the east, this point is halfway below the horizon in the west. The arc of a rainbow is 42 degrees away from the antisolar point, so that means if the sun is 42 degrees high, the rainbow will be a tiny spot on the horizon. Also, if the rain is not within 42 degrees of the antisolar point, there will not be a rainbow. Simply, the sun has to be low and not near rain.
What are you talking about exactly here? The speed of light is constant, if you where moving at the speed of light towards a light source then the light coming from that light source would not approach you at twice the speed of light. I am not confident enough in my understanding of special relativity to explain why but there is a video on that here on Sixty Symbols. Light traveling through water isn't slower, it just takes a longer route to get to you making it relatively slower.
Objects can be moving away at the speed of light, but they both have to be moving. For example, if you're in a ship going half the speed of light in one direction, and another ship is going half the speed of light in the other direction, you're moving away from each other at the speed of light. The effect should be that the other ship is very dim and redshifted. I imagine it would also appear that time was slowed down by half on that other ship. Not 100% sure, though. Ask a relativity expert! :D
Yea, I posted it just after he mentioned the double reflection bit. It's amazing how you could actually have an infinite amount of rainbows... Perhaps we could see them using digital editing...
it is not going at speed C in water. There is a phenomena known as a photonic boom. It happens like a sonic boom but with light. A partical (like a neutrino) traveling at 99.9% C in a vacuum hits a medium like water, its still going 99.9% C, while the speed of light is lowered to less than 99.9%C in the water. The result is the neutrino catching up to the light it gives off (like a plane does when hitting the speed of sound) and creates a shock wave of light.
A normal circle is the set of points which are a given distance (the "radius") from the centre. A rainbow appears at the set of points which make a fixed angle between you and the sun. It's slightly different from the normal definition of a circle, because it's the angle that is fixed, not the distance, but that's OK, because when we see things we only see their direction, not their absolute position. The sun's diameter is not significant here; it would work if the sun was a point of light.
Knowing how it forms is definitely more beautiful, anyone can see the colours and appreciate them, but how many people can look at the dark section between the rainbows and appreciate that?
How happy we should feel that we live in an age that we can explain things like these, even though is fairly easy to explain, and we are not given some stupid explanation that involves gods/magic/mythical creatures etc .
You are right, the exiting angle will be the same as the angle of incidence because of the internal reflection and the fact that the ray is going through the same media. The only difference would be that it was displaced by the glass a little bit from the usual path of the light.
The "velocity" of light slows down, not the speed, due to directional changes that deviate from a straight path thus the changes in vectors add up to a lesser degree when going through a medium (due to photon - electron interactions with the atoms within the medium).
No, not the sun's diameter, but the sun's position. Mike drew horizontal lines, and the 42° is always with respect to that line. If the sun is higher in the sky you'll see the rainbow at a lower angle with respect to the horizon, and if the sun is higher than 42° you can't have rainbows at all. You may have noticed that rainbows only appear early morning or in the evening, before sunset.
Brilliant as ever. Such a good channel, I just got an offer to study physics at Nottingham, and I probably wouldn't have applied if it wasn't for these videos (and Nottingham being quite such a good place to study physics). Thanks Brady, Prof. Merrifield and everyone else involved :D
Question for sixty symbols : What happends beyond the red and violet stip of light when a rainbow is seen in the sky? I mean, are there any infrared and ultraviolet colours that our eyes aren't capable of seeing? If we filmed a rainbow with a special camera sensitive in ultraviolet/infrared what we would see? I have always wondered about that...
Here's a completely unrelated question I had earlier today that I didn't know where to ask so I'm resorting to the comment section. I know you can make antimatter and that it can be made into antiatoms like antihydrogen and antihelium. But what would happen if we theoretically made an atom that is radioactive like antiuranium or something similar? Would the radioactivity be the same? Would the waves be different as in anti-radiation?
c is the thing that is considered constant. c is the speed of light in a vacuum meaning, the light has no resistance, thus it is at its fastest. light can move quite slow, depending what its traveling through. i believe the slowest recorded speed of light was 38mph.
So in Star Wars terms the midi-chlorians are like rain drops and the Jedi are force sensitive rainbows. Knowing more about Force sensitivity doesn't detract from the magic of Jedi, it only adds to it. :)
in 3D, you can take the same 2D-angle (42) and rotate it's plane around. All those positions would still have 42 degrees in relation to the sun satisfying 'rainbow criterion'. Rotating a 2D-angle around produces a cone shape called steric (3D) angle. If you were traveling in a plane, you would see the whole rainbow circle produced by the projection of that cone (normally half of it is covered by the Earth). Cone moves along with the observer so no crossing the rainbow :P /watch?v=7k85eD_tQZo
There are infinite ways light can be reflected. It can get stuck inside a water droplet until the end of times as long as the reflective surface is a perfect mirror. Take a camera and expose it to a double or triple rainbow for a period of time and you will eventually get quadruple, quintuple, sextuple and so on rainbows. As long as your exposure doesn't get flooded with "white" light you will see the entire rainfilled sky as a color show.
You can test your theory by shining two light sources at different angles into a bowl of water and observe. The angles you derive from your experiment can ultimately provide you with the answer. But to be frank, one of two things would happen... 1. You get a higher frequency of double, triple and quadruple etc rainbows as long as both suns are close together and behind you towards the rain shower. 2. You get single and double and the occasional triple rainbow because the suns are too far apart.
Maybe the other colors became to faint to view any more? I've heard that because reds the longest wavelength, it makes it the most visible color. I'm not sure though. Anyone feel free to correct me.
I guess there will be a ultraviolet/infrared band. After all even Newton found the infrared band using a prism (the wall beside the red band where apparently no light was shining was the hottest) and raindrops are basically the same as prisms in this context.
No, I don't believe it is. He described what you were describing - when light interacts with a medium, its speed in a certain direction is reduced. However, total speed is still constant, as the reduction is simply a conversion. If a photon was moving horizontally, and it interacted with a medium, then some of the horizontal speed is changed into vertical (and a hell of a lot of other directions) speed. Neutrinos, however, don't interact with mediums like water - that is what causes that effect.
You know, when i first saw this channel i thought it was gonna be a boring one w/boring people talking in a boring fashion difficult for most to hold on to w/no passion, like allot of these programs are, but everyone here is always so passionate and exited and explain things in such a meaningful way that's easier to understand. I love it and think this is what we need more of. Keep up the great job! 👍
Ok
Thanks for this. I agree that understanding something "beautiful" actually adds to the experience rather than ruins it. I think the night sky is a very good example of that!
"...so I have here the sun and a raindrop (not to scale..."
Thank you, professor, for clearing that up! ;)
LOL yeah without that fair warning someone could get confused... teehee
That was one of the clearest, most lucid explanations I've ever heard about this subject. Thanks guys!
Very well thought out explaination. I've long known that rainbows were caused by reflections in the droplets, but had never really wrapped my head around how exactly, even through I'm pretty good at physics. This video just explained it so well. Keep 'em coming, Brady
share it with some friends... that is even better than a like!
I will
do we know why the second rainbow is positioned "outside" or the main rainbow and not inside?
at the final, 6 :30 , it sounds like a R. feynmann quote "science knowledge only adds to the excitement and mystery and the awe of a flower.
It only adds. I don't understand how it subtracts."
nice video congrats sixty symbols
The exact same thing as described in the video. Due to the angles that make the reflection work, a rainbow is always a circle, and if you could somehow see your own shadow when looking at it, it would always be in the center because the sun is always precisely behind your back when facing a rainbow.
Earlier this summer, I was fortunate to spot a rainbow caused by a sun that hadn't even risen. Huge, round and high up in the still slightly dark sky, thanks to the sun being so low. Wonderful.
This is the BEST Sixty Symbols video I've seen so far. Thank you!
Thank you Thank you Thank you!
I've read explanations before, and they've always left me feelings frustrated, and without a FULL explanation. This has given me the FULL picture!
I love Mike's explanations! He's an awesome dude!
It's simply a third internal reflection in the rain drops. Each time light encounters an interface with a different refractive index (the interface between the water inside the droplet and the air outside) under a steep enough angle, you get part of the light being refracting (i.e. passing through the interface) and part reflected. It's kind of like a round semi-transparent mirror. The light can bounce around in the droplet quite a few times, but each bounce attenuates it significantly.
When Prof. Merrifield, began speaking about beauty platonic and intimate(technical) beauty, I was immediately reminded of a conversation Richard Feynman once had with an artist. It's quite poetic how the father of quantum electrodynamics and this seemingly unrelated thought are intertwined. Feynman's Rainbow~ :D
I enjoy the comment sections in Brady's channels because they are generally intelligent and kind comments
thanks - and thanks to our viewers for the photos! (follow us on Twitter and/or Facebook for alerts about photos we may need!)
I have to agree with you on that. It would be like saying that studying botany or horticulture diminishes the beauty of a garden, when (in my opinion) the opposite is true. If you were to walk through a garden with a botanist/horticulturalist, I'm sure that they would see and appreciate the same beauty as you (as well as picking up on several things that you probably didn't know/notice).
I really enjoyed seeing at least ten vertical rainbows in Iceland during the Midnight Sun. It was around midnight, too. Very pretty, partial rainbows. I live outside Paris, France and know of a place where you can almost always see full rainbows if there is the slightest weather change. It's so cool!
5:55 that's mine :)
Thanks Brady.
I agree, understanding how something works doesn't ruin its aesthetic value, it actually enhances it. If you admire the beauty of something so much, don't you want to know what makes it so beautiful?
Yes, and also keep in mind that the drops of water are not stationary, so the drops you see the rainbow off is constantly changing.
Having read Walter Lewin's "For the Love of Physics", which contains a whole chapter about rainbow physics, I appreciate rainbows only more. One day, when I went to Wageningen to check out the university, it was somewhat rainy all day but not particularly cloudy, perfect rainbow weather. So I faced the sun, turned around, looked at my shadow, turned 42 degrees, and there it was: a perfect rainbow, with another one around it. In the early evening waiting for the bus I got to see another double.
You're correct. Inside the violet arc is an ultra-violet arc - porbably visible to bees. They can see UV.
Outside the red arc is a very, very faint infra-red arc. Theoretically visible to night-vision goggles... although you'd be blinded by the brightness of the rest of the rainbow if you put them on!
For the last part, there are always the people who need to not know how things work to appreciate them, and people like us who grow a deeper appreciation knowing how things work. It applies to favorite movies and magicians' tricks, for examples that science lovers might better see why a lot of people are disappointed to know the facts. Learning the truth about "the smell of rain" both killed the romantic aspect and gave me clarity about why it always smelled earthy rather than like water vapor.
The secondary rainbow is at 50°-53°, the primary between 40° and 42° (42° is for red, 40° is for blue). There are ternary rainbows, but they're very rare because they are so faint. While for primary and secondary rainbows the light is reflected back, for ternary the 3 reflections make the light go the same direction as it entered. That's why you'll see ternary rainbows in the direction of the sun, instead of the opposite direction.
Don't forget to mention Al Hacen who first correctly described the phenomena of the rainbow. He also came up with the perplexing "2 points in a circle" geometric construction problem.
Nicely explained. And I like your closing remarks particularly.
If you'd show any scientist a bus that goes through the air, I can assure you that they'll be blown away. Anyway, it is magical if you understand it, you can look at the way the wings work, how they keep a 187,700 pound plane from falling; you could look at the way we managed to control those wings, the electrical circuits, the controls that the pilots have in their hands, or in the reach of their hands; you could look at the amount of gas each one needs to stay in flight and be astonished.
Yes. The photons are being absorbed by ground state electrons of atoms that the photon contacts, which causes a delay, and then the photon is re-emitted as excited electron decays back to its lower energy molecular orbital. The photon then travels to the next atom's electron within the medium at the speed of light. All this interaction causes deviations in an ideal straight path, the increases the total distance traveled proportional to the time passed, keeping the speed constant.
The bit at the end about people asking if know why makes it less beautiful is the best part of the video.
People who say that understanding how something works makes it less beautiful drive me crazy. I think you must have a very limited imagination if you need something to be "magical" (i.e., beyond comprehension) to be amazing. (Nevermind that the physics are true, whether or not you're paying attention.)
I really enjoyed this video!
Dear Sixty Symbols, can you please have these professors explain in their wonderfully round way the issues relating to the Earth's climate in a series of videos? Their insight is needed.
It's not the "total" distance / time that decreases. That remains constant. The straight line from A to B through a medium (without taking into consideration the distance light has traveled in all other directions) distance / time does decrease.
Nonsense. Everyone knows there's a Leprechaun and a pot of gold at the end of a rainbow. What is this mythic refraction you speak of?
Common misconception. The leprechaun is in the middle of the circle. Do you have to go up in a plane to see him. And, since he's on the ground, you can't catch him from up there. I mean, that's just science
false.
What you saw is a somewhat more complex optical effect called "the glory" or the "Brocken Spectre". There are plenty of videos of the effect here on youtube.
Regarding that question at the end, my personal response to that is:
.
The things that are truly amazing things are the ones that continue to be amazing after you understand them.
1. The sun might not always be able to hit the rain with enough intensity to cause a rainbow.
2. Heavy rain, such as would produce a vivid, memorable rainbow usually occurs in the afternoon and evening with showers and thunderstorms, if you are in the United States, storms most often move west to east and usually have dry air behind them, either as part of the storm or a larger air mass. This clears the air of clouds and lighter rain behind the heavy rain, allowing the sunlight in.
It is actually not "bouncing" that causes light to slow down in a medium, but the absorbtion of light by atoms and the time it takes them to re-radiate the light again.
And as as far as the explanation for the refraction goes. You could compare it with a man in a wheelchair reaching a plane coated in honey at an angle. First one of his wheels will slow down while the other will continue at normal speeds and this will cause the wheelchair to turn.
Every rainbow is technically a double rainbow. It's just the 2nd one might not be visible (too dim/obscured/etc), or barely at all.
Interesting video!
This is an invitation to see an artist theory on the physics of light and time!
This theory is based on just two postulates
1. Is that the quantum wave particle function Ψ or probability function represents the forward passage of time itself
2. Is that Heisenberg’s Uncertainty Principle ∆×∆p×≥h/4π that is formed by the w-function is the same uncertainty we have with any future event within our own ref-frame that we can interact with turning the possible into the actual!
This guy is to me amazing. Thank you for making these videos Brady!
You probably saw an ice halo instead of a rainbow. Look up "atmospheric optics" and then click on the ice halos section and you'll get a very good explanation and some very pretty photos as well.
Yes it is. In order to see the colored light you have to look in a certain angle at the raindrops, resulting in a cone starting at your eye where raindrops are in the right position, that's the circle you see. But this was talked about in the video, so I don't get how you cannot get this.
Re-read my comment... the speed of light (denoted by the constant 'C' as used in E=MC²) is CONSTANT, when going through a medium such as water it still moves at the speed of light (the same as in a vacuum) but it bounces around a lot more and therefore it takes longer for it to travel in a straight line from point A to point B. It bounces around but it still moves at the speed of light.
I once saw a circular rainbow around a full (or very nearly so) moon. The effect was very clear and the spectrum(?) of colours was restricted to blue, indigo (is that still a valid colour name?) & violet. It was very beautiful.
Ps. Enjoyed the video very much, thank you for your continuing efforts.
An evening, during a landing in an airplane, we descended into a slightly transparent cloud. I witnessed two fully circular rainbows, with the shadow of the plane dropping in the middle of it... Single most amazing thing I've seen in my life.
I see those all the time when I'm on the ski slopes in winter. The halo is then caused by tiny ice crystals in the air. The crystals refract the light the way raindrops do. The dispersion in ice is greater than in water, that's why the colored band you see is wider (and fainter) than a rainbow.
Yes, this is actually how infrared and ultraviolet were discovered, via an artificial rainbow made with a prism. Look up William Herschel for the discovery of infrared and Johann Ritter for ultraviolet. They used two different methods of detecting the light, both are pretty clever.
They explain that in the video! They're a circle, but some portion is below the horizon / doesn't have raindrops in it.
i don't think this has explained why it looks beautiful, but I think this has explained what makes the beautiful thing.
I enjoyed you video.
Understanding things makes one appreciate them less? On the contrary I never cared for sunsets or rainbows at all until I understood what caused them. Now I can sit and stare at them for ages admiring not only the innate beauty but also the beauty of the physics as well.
It is a common misunderstanding that the colors in the secondary rainbow are reversed. The are actually upside down. The difference is subtle, but true. Technically, red is on the _outside_ of both rainbows, but in the secondary outside is _down._
The white part mentioned at 3:30 is not just a small area. It actually goes all the way to the center of the rainbow; well, if there are raindrops there. In the primary rainbow, it is at the shadow of your head. Think about the light that hits the drop right in the center, bounces straight back, and exits. This is the center of the primary rainbow.
For the secondary this light reflects twice, and exits the raindrop in the exact same direction as the original ray of sunlight. So the "center" of the secondary is on the sun itself. But the rainbow itself is about 130 degrees wide. It fills the "sun side" of the sky, wraps around the top, and is seen upside down about 50 degrees from the shadow of your head.
No, you don't see a third rainbow this way. I'm not saying that it can;t occur, but it would be seen on the sun-side of the sky. Same with the fourth order. They have been photographed, but are very dim to the naked eye.
Agree that understanding why the effect happens adds to the wonder and beauty of it.
Because the distance between the point of refraction, and the point where you pick up the light (the retina) has a big influence. The farther the light travels after being refracted, the more it gets dispersed. So it does indeed undergo dispersion in our eyes, just doesn't get spread enough out to be noticable.
Theoretically this is possible... kind of. But almost definitely not in the way you're imagining it! Watch sixtysymbols video on Young's Double Slit (I'm just assuming there is one!)
Imagine that the point you are looking at is at 0 degrees, if you look straight to your left, your right, up or down you are looking in 90 degrees from your original viewpoint.
at angles of 42 degrees you will see the light (which is coming from behind you, otherwise you don't get a rainbow) reflected back to you. That 42 degrees can be anywhere to the left/right or up/down or a combination of them like up to the left. If you are up in the air with the sun behind you then you get a full circle.
I've seen a picture of a full circle rainbow online somewhere, I believe it was taken at a waterfall. Very cool. I believe to that the 'Gold at the end of a rainbow' thing was a kind of inside joke with the Irish or whoever because they understood they were a circle and had no end =). Science and Historic humor ftw.
understanding things in the world and universe makes me appreciate it more.
Love Sixty Symbols, I could listen to all the professors all day! I only got Science double award in secondary school but seem to have carried on my learning experience after school with self study. I usually read about Evolutionary Biology and Ecology which I really do love. But I've been sucked into Quantum Mechanics over the past few months as the Quantum world is so bloody interesting. Thanks for the great Channel best regards from the locals at Kirk Hallam (just down the road) :P
Thanks for the tip. What I meant when I asked was not there, unfortunately. Once I saw someone asking why does the speed of light changes when it goes from one medium to another, when light speed should be a constant, and the answer was that, in fact, the speed is always the same, but in a more refringent medium it bounces back and forth, taking more time to cover the same linear distance (that's what I mean by microscopic explanation). I'm still not clear on why it changes angle though.
Well, if you have a very long arm, it should be possible to place your hand between the droplets responsible for the point where the rainbow meets the ground, as seen from the location of your eyes. Or you could place some device which could detect (and grab) pots of gold, and place it at a given point (a point with droplets, surely), then calculate where you need to place your eyes in order to have that specific point with the "Pots-o-Goldiator" be the right one.
no ,no. im saying that the reason the colors bend at different angles are due to the wavelengths of light. this has to do with conservation of momentum and energy, so because light slows down when entering water from air, the phase angle must change to keep the frequency constant. and since blue light has a longer wavelength, the phase angle change is larger (thus more bent) than that of red light. (also i made a small mistake in the other comment, frequency =/= wavelength). hopefully that helps
things (planes, birds and the universe) are complicated. every solved mystery raises even more new ones usually. more magical stuff to ponder. it explains why scientists are not the most bored by the universe but the instead the ones who find it most fascinating.
Different materials bend light differently. If you shine light upward from underwater to air, it'll go straight through, but at 45 degree, the light'll come out at a smaller angle say 30 degree. So you can imagine that if you tilt the light more, to say 15 degree, then it'll come out exactly parallel to the surface of the water--or get bent so much it can't escape and reflects instead.
Nice! When he just explained, that the colors of the second rainbow are reversed because of the second reflection, I went " Ohh, this is so cool!"
Man, I love science!
The "speed" (total distance/time) is still the speed of light while the "velocity" (displacement; depends on two points of final and initial; final position - initial position / time) is slower because the denominator, time, increased while the "displacement" for both un-refracted and refracted light rays remained the same.
Your all awesome! I knew the answer but I still end up understanding it even further. I love learning in such an enjoyable way. This and your double vision are superb vids
+1 for science not detracting from wonder
Circular pattern: suppose the sun rays are horizontal. All the raindrops will create rainbows in a 42° cone with the sunray as axis. Most of these will miss your eye. The ones you'll see are the ones where your eye is on that cone. That cone is a full 360° so if the drop is below you at 42° you'll also see the spectrum. So when you're up in the sky the rainbow will become a full circle, caused by all the raindrops which create a 42° angle between you and the sun.
No. A flashlight literally creates photons when it shines. An electric current heats the filament. As the filament heats, the electrons in it become excited and start wiggling. When electrons wiggle, they send off packets of energy in the form of electromagnetic radiation (aka light). So yeah, it does "just convert energy from one form to another," but light is basically just a way to move energy around.
Besides, where else do you suppose the light comes from?
i agree, it does add to the beauty, understanding something takes nothing away, i dont need to believe something is "magic" to see it as beautiful. I wish some people didnt think that way.
Rainbows are centered around the antisolar point, which is a point directly opposite of the sun. If the sun is halfway up the sky in the east, this point is halfway below the horizon in the west. The arc of a rainbow is 42 degrees away from the antisolar point, so that means if the sun is 42 degrees high, the rainbow will be a tiny spot on the horizon. Also, if the rain is not within 42 degrees of the antisolar point, there will not be a rainbow. Simply, the sun has to be low and not near rain.
glade there is a person there asking the right questions people make videos explaining things but not asking the right questions.
What are you talking about exactly here? The speed of light is constant, if you where moving at the speed of light towards a light source then the light coming from that light source would not approach you at twice the speed of light. I am not confident enough in my understanding of special relativity to explain why but there is a video on that here on Sixty Symbols.
Light traveling through water isn't slower, it just takes a longer route to get to you making it relatively slower.
I love both of you, never thought there are some many things about rainbows that I don't know
Objects can be moving away at the speed of light, but they both have to be moving.
For example, if you're in a ship going half the speed of light in one direction, and another ship is going half the speed of light in the other direction, you're moving away from each other at the speed of light.
The effect should be that the other ship is very dim and redshifted. I imagine it would also appear that time was slowed down by half on that other ship.
Not 100% sure, though. Ask a relativity expert! :D
Yea, I posted it just after he mentioned the double reflection bit.
It's amazing how you could actually have an infinite amount of rainbows... Perhaps we could see them using digital editing...
it is not going at speed C in water. There is a phenomena known as a photonic boom. It happens like a sonic boom but with light. A partical (like a neutrino) traveling at 99.9% C in a vacuum hits a medium like water, its still going 99.9% C, while the speed of light is lowered to less than 99.9%C in the water. The result is the neutrino catching up to the light it gives off (like a plane does when hitting the speed of sound) and creates a shock wave of light.
Like Prof. Merrifield said, you can even have triple rainbows (6:17), the refraction path taken by the light is just different yet again.
A normal circle is the set of points which are a given distance (the "radius") from the centre. A rainbow appears at the set of points which make a fixed angle between you and the sun. It's slightly different from the normal definition of a circle, because it's the angle that is fixed, not the distance, but that's OK, because when we see things we only see their direction, not their absolute position.
The sun's diameter is not significant here; it would work if the sun was a point of light.
Brady, you should do a video showcasing the major things YOU have discovered while making these films and how they have changed your outlook on life!
Knowing how it forms is definitely more beautiful, anyone can see the colours and appreciate them, but how many people can look at the dark section between the rainbows and appreciate that?
How happy we should feel that we live in an age that we can explain things like these, even though is fairly easy to explain, and we are not given some stupid explanation that involves gods/magic/mythical creatures etc .
You are right, the exiting angle will be the same as the angle of incidence because of the internal reflection and the fact that the ray is going through the same media. The only difference would be that it was displaced by the glass a little bit from the usual path of the light.
The "velocity" of light slows down, not the speed, due to directional changes that deviate from a straight path thus the changes in vectors add up to a lesser degree when going through a medium (due to photon - electron interactions with the atoms within the medium).
No, not the sun's diameter, but the sun's position. Mike drew horizontal lines, and the 42° is always with respect to that line. If the sun is higher in the sky you'll see the rainbow at a lower angle with respect to the horizon, and if the sun is higher than 42° you can't have rainbows at all. You may have noticed that rainbows only appear early morning or in the evening, before sunset.
Brilliant as ever. Such a good channel, I just got an offer to study physics at Nottingham, and I probably wouldn't have applied if it wasn't for these videos (and Nottingham being quite such a good place to study physics). Thanks Brady, Prof. Merrifield and everyone else involved :D
Question for sixty symbols : What happends beyond the red and violet stip of light when a rainbow is seen in the sky? I mean, are there any infrared and ultraviolet colours that our eyes aren't capable of seeing? If we filmed a rainbow with a special camera sensitive in ultraviolet/infrared what we would see? I have always wondered about that...
Yes, he is very clear and concise. Something to be admired in a teacher I would say.
The last one was beautiful and most vivid.
Here's a completely unrelated question I had earlier today that I didn't know where to ask so I'm resorting to the comment section. I know you can make antimatter and that it can be made into antiatoms like antihydrogen and antihelium. But what would happen if we theoretically made an atom that is radioactive like antiuranium or something similar? Would the radioactivity be the same? Would the waves be different as in anti-radiation?
Once again, "42" proves itself to be the answer to life, the universe, and everything.
c is the thing that is considered constant.
c is the speed of light in a vacuum
meaning, the light has no resistance, thus it is at its fastest.
light can move quite slow, depending what its traveling through.
i believe the slowest recorded speed of light was 38mph.
So in Star Wars terms the midi-chlorians are like rain drops and the Jedi are force sensitive rainbows. Knowing more about Force sensitivity doesn't detract from the magic of Jedi, it only adds to it. :)
Good to see nyancat making a long-overdue appearance in this video! =]
in 3D, you can take the same 2D-angle (42) and rotate it's plane around. All those positions would still have 42 degrees in relation to the sun satisfying 'rainbow criterion'. Rotating a 2D-angle around produces a cone shape called steric (3D) angle. If you were traveling in a plane, you would see the whole rainbow circle produced by the projection of that cone (normally half of it is covered by the Earth). Cone moves along with the observer so no crossing the rainbow :P /watch?v=7k85eD_tQZo
There are infinite ways light can be reflected. It can get stuck inside a water droplet until the end of times as long as the reflective surface is a perfect mirror.
Take a camera and expose it to a double or triple rainbow for a period of time and you will eventually get quadruple, quintuple, sextuple and so on rainbows. As long as your exposure doesn't get flooded with "white" light you will see the entire rainfilled sky as a color show.
You can test your theory by shining two light sources at different angles into a bowl of water and observe. The angles you derive from your experiment can ultimately provide you with the answer.
But to be frank, one of two things would happen...
1. You get a higher frequency of double, triple and quadruple etc rainbows as long as both suns are close together and behind you towards the rain shower.
2. You get single and double and the occasional triple rainbow because the suns are too far apart.
What are the physics behind a triple rainbow? Is it inverted again compared to a double rainbow?
Yes.
Why is it so red though? The one I saw was this big wide band of almost blood red.
Maybe the other colors became to faint to view any more? I've heard that because reds the longest wavelength, it makes it the most visible color.
I'm not sure though. Anyone feel free to correct me.
Every rainbow is technically a double rainbow. It's just the 2nd one might not be visible (too dim/obscured/etc), or barely at all.
I guess there will be a ultraviolet/infrared band. After all even Newton found the infrared band using a prism (the wall beside the red band where apparently no light was shining was the hottest) and raindrops are basically the same as prisms in this context.
No, I don't believe it is. He described what you were describing - when light interacts with a medium, its speed in a certain direction is reduced. However, total speed is still constant, as the reduction is simply a conversion.
If a photon was moving horizontally, and it interacted with a medium, then some of the horizontal speed is changed into vertical (and a hell of a lot of other directions) speed.
Neutrinos, however, don't interact with mediums like water - that is what causes that effect.