How Do Rainbows Form?
How Do Rainbows Form?


To make a rainbow, you need three ingredients:
sunlight, water, and you. Sunlight, as you probably know, consists of
all of the colors in the visible spectrum, as well as a bunch of wavelengths of light
that we can’t see. And when light travels from one medium — like
air — to another, denser medium — like water — it slows down, and exits the new medium
at a different angle than it entered. This is called refraction. In the case of water, light can enter a droplet,
bounce off its inner surface, like a mirror, and then exit at sharp angle. And because each color has a different wavelength,
they’re each slowed to a different degree and refracted at a different angle. So red light will exit the drop at 42 degrees
from the angle at which the sunlight entered. But blue light, near the opposite end of the
spectrum, will exit at 40 degrees, with the other colors somewhere in between. The combined effect of this differently refracted
light scatters the colors so you can see them individually — ROYGBIV. And this is also where you enter the equation,
because the conditions have to be just right. Rainbows only happen when the sunlight is
coming from behind you and is low in the sky. As the sunlight shines into a curtain of raindrops
in the air in front of you, only one color from each droplet will refract at the exact
angle necessary to directly reach your eye. So in one part of the sky, all the raindrops
will bounce red light into your eye. All the other colors from those particular droplets
will scatter either too high, too low, or too far to either side for you to see them. But just a few degrees away in the sky, the
blue light bouncing out of those raindrops will be the ones to reach you. With all those droplets refracting only a
certain wavelength of light that hits your eye, together they create the illusion of
a rainbow. So what creates the “bow” in a rainbow? Well, rainbows actually form in a full circle
in front of you, at an angle of 40 to 42 degrees from your line of vision. This means you’ll always be at the center
of any rainbow you see! Which is kind of a nice thought. But it also means that the Earth is going
to block the lower half of the rainbow, so you typically only see the upper arc. However, some extremely lucky skydivers, pilots,
and mountaineers have gotten high enough above the horizon precisely in the right conditions
to see a full circular rainbow. It DOES exist. But I am perfectly happy just seeing half
of the rainbow and staying right here on the ground, thank you very much. Thanks for asking, and thanks especially to
our Subbable subscribers who get these videos a little bit early, for subscribing. Thank
you! If you want to get these videos early, you can go to subbable.com/scishow. If you have a quick question for us, you can
let us know on Facebook and Twitter or in the comments below, and if you want to keep
getting smarter with us, just go to YouTube.com/scishow and subscribe!

98 thoughts on “How Do Rainbows Form?”

  1. Leopold "Butters" Stotch says:

    Richard of York gave battle in vain. sounds a bit better than roy g biv.

  2. Nemo Forvermore says:

    I didn't like science in school because my teachers completely took the magic away from the things themselves the way they explained them. Thank you so much for explaining and at the same time giving all those things their magic back!
    (I' sorry, I guess my English is not too good :-/ ) 

  3. Joe says:

    You can see an almost complete rainbow by placing a sprinkler under a large trampoline and jumping on it on a sunny afternoon. If it's the right time of day, as you jump on the trampoline, water dropletts will bounce up and catch the sunlight and form a rainbow circle ("raincircle"?). The only part that's blocked will be where your feet are.

  4. By Zippy says:

    Jesus forms the rainbows

  5. Skroot says:

    We make rainbows!

    /gay

  6. Loner Gang says:

    Why do dogs bark? Why does it rain?

  7. NEVER ? THE CREATOR, ? THE CREATION. . . says:

    SHAME ON YOU FOR BELIEVING THE DEVILS LIES FED TO YOU, PICK UP THE KING JAMES N READ IT STOP LEADIN YO BHYND TO HELL AIGHT!

  8. Shaw Thing says:

    What about upsidedown rainbows? I see one the other week for the first time in my life and it boggled my mind.

  9. Rik Schaaf says:

    I've seen a full "rain"bow while using a garden hose.

  10. NENE71984 says:

    Why do I see light when I rub my eyes? What causes it?

  11. No Name says:

    It is pretty easy to make a rainbow just get a hose and put the nozzle on mist but make sure you have sunlight. You can also make a circular rainbow just as you make the rainbow with the hose just do a circular motion and you will see it.

  12. Manuel Quiche says:

    No sirve este programa de descarga

  13. benjamin rackz says:

    what color rainbow would a dog or cat see????
    that should be a topic 4 a show!!!

  14. Wilf Reynolds says:

    thanx!!! helped a lot!!!

  15. Hazelstorm says:

    I once saw a circular rainbow around a light post… is that normal?

  16. Mekhi Williams says:

    What causes sugar to be so sweet

  17. elfishy says:

    There is the chance to see a circular rainbow while meeting the same conditions (skydivers etc.) when using a shower attachment on a hose. Stand with sun behind you, looking slightly down on the shower that is very close, make sure you don't shadow the water spray… Give it a try 🙂

  18. Nem says:

    i've seen a full rainbow on land by looking up at the sun while wearing my glasses in the "sunglasses" mode. it was so cool xD you jelly hank?

  19. Nicole Whitney says:

    Isn't this John Green's brother? 🙂 They talk the same way. lol

  20. Morris Celica says:

    Please explain rainbow around the sun

  21. MsWorkalittle says:

    I have been lucky enough to see a circular rainbow from the window of an airliner and the shadow of the plane could be seen in the center of the rainbow. It was spectacular.

  22. Ciroluiro says:

    But why exactly is it a circle? Is it because the sun is a sphere?
    It sounds like a silly question but in reality it isn't. It is like if you had to explain to someone how you do to ride a bike. You can give instructions on how to use the bike, but the real answer would be to explain all the factors like gyroscopic precession, measuring the balance, torque, friction, and how you combine them. Your brain does that automatically, but it really doesn't know how.

  23. Master BAM says:

    Why do we speak different languages

  24. MrWeedWacky says:

    so the answer to rainbows is also the answer to life and everything inbetween… 42

  25. Rushabh Sanghavi says:

    I thumbed this down for explaining science without diagrams or graphics. You're talking about rainbows here. Explaining geometry using just words is a terrible idea.

  26. David says:

    Great explanation, and – crucially – great diagrams to drive the point home!  Thank you!

  27. Brian Keller says:

    Once I saw a rainbow that ended at a bank. So you will find a pot of gold there (not that US currency is actually made of gold) !

  28. ZebrasFirst says:

    I guess this scientific explanation disproves Genesis 9: 13 – 16. 🙁  sorry, christians

  29. Jossie Mime says:

    Ok, so … why is it a circle?

  30. James Gallinaro says:

    mlg

  31. The Weird Dudes says:

    hey

  32. zLeveling Gaming says:

    i thought theyre unicorn farts

  33. JAMES LOWE says:

    Why is pulmonary fibrosis incurable?

  34. Anna Millar says:

    I am 13 and so confused when we learnt about rainbows in science. I watched a few videos but this was the only one that explained so well that i understood everything!!!! thankyou so much for this video, I understand now

  35. shalini darbha says:

    ls some one behind you with a stick!!!.. why so fast explanation!!!!

  36. CLARIAN KEN says:

    and what would happen if i stepped on a raknbow??

  37. XPJV says:

    rainbow caused because of hard surface firmament on a flat earth!

  38. Alp Ozen says:

    U copied the style of crash course — john green

  39. Quaker Parrot says:

    I've seen a double rainbow

  40. hoochie snoop says:

    slow down , didn't understand shit.

  41. Jacob Paniagua says:

    I once used a hose to see a fully circular rainbow. it was cool.

  42. NeoNinja says:

    Lies, dosnt explain or make sense why its that constant shape, and why it dosnt work inside, the rainbow its the reflection of the dome we live under.

  43. Faroek Nasierkhan says:

    Sun light is dispersed by water droplets in the atmosphere and they are observed as arches due to the way in which the light refracts. The way in which we experience rainbows and colors in general may be unique to the way we process information, but photons and the spectrum in which they exist do react to the physical world in an objective, formulaic way, including dispersing at different wavelengths.

  44. Anonymous Chicken says:

    I was taught that God put the rainbow in the sky as a sign that he would never flood the whole Earth again. Which one is correct?

  45. Tiar Salsabila Fitriazaki says:

    why did i cringe

  46. Shrishail Gharat says:

    Does it mean that there are multiple rainbows but we just can't ya know, see them ???

  47. rey sanchez says:

    I followed a rainbow and I found a old knife.

  48. Kishore Chandra Parida says:

    THere is something wrong

  49. XDoomkaiserX says:

    Don't you just love when he says "Well what creates the bow in a rainbow?" and then never explains it.

  50. Giarc66 says:

    for me I heard so many words come from this guys mouth but at the end have no clue what he said! anyone?

  51. Vinay Velicheti says:

    super explanation ……….

  52. BubbleryHD _ says:

    i was having a shower and a little bit of fucking rainbow showed up.it was pretty terrifiyng actually..

  53. Bala Bharathy says:

    speak slowly fork…we can follow much clearly

  54. Lucarius1 says:

    I often just see half a rainbow, that only go from the gound to the middle of the sky, but does not go back to the other side of the gound. In fact I rarely see a rainbow that goes from one side fully over to the other side. But double rainbows are more common here in Scotland…

  55. deceptichris says:

    Shine your phone light at a snowglobe and you will also see a rainbow. It works on a small scale the same way it works on a large one.

  56. Thomas William Johnson says:

    jesus is a rainbow hahahahah

  57. Gypsy Blu says:

    so explain to me why I was able to see the end of a rainbow? it wasn't a full circle.

  58. steve armstrong says:

    Some of this is wrong and should be revised.

  59. Xcellance says:

    In order to create a rainbow indoors it requires a light source, water and mirrors! Knowing this I ask where are these mirrors outside?

  60. Rommelyn Guardamano says:

    WHY DO U TALK SO FAST?

  61. Ilikecars Andsport says:

    You pray so much

  62. Julia Gustepa says:

    I saw the full circle, it wasnt very big and also pale.

  63. Raghuveer Singh Rajpurohit says:

    how there are bands of color at macroscopic level and don't get mixed .please reply .

  64. camry1971 says:

    For a rainbow to form you need a prism, concave mirror and your eyes to see. The top portion of the water droplet (Sphere) would work like a prism and the farther portion of the sphere is the concave mirror that will reflect 1 of the essential colors to you eyes.. This guy failed to address the prism and the concave mirror clearly!!!

  65. MUI GOKU says:

    I saw a rainbow before at school

  66. Ryan Martell says:

    but how do they shape

  67. Liam Clarke says:

    Such great content

  68. Ipad 5 says:

    why rainbow stays is stationary? and why we cant see all directions?

  69. Lil Swerveyy says:

    Why don’t my lights act like the sun and make a rainbow when I wash the dishes indoors ???? We live in a dome

  70. Vicky Nelson says:

    no pot o gold den aye?

  71. peter beltran says:

    Im just seeing rainbow

  72. micah hook says:

    What causes the bow?

  73. Janjan Abc says:

    you explaine nothing

  74. ShanSan_Moon YT says:

    I still don't understand 😅
    Sorry because I'm going to face my last exam next month Soo if I can't understand this chapter I die cuz I can't continue

    Q: Why Red light is faster than Violet light??

  75. VA-VA-VOOM HONEST says:

    how big are the rainbow's this guy has seen???

  76. TEKON SP33D says:

    Who just saw a rainbow

  77. Rob G says:

    Some say,Rainbows are made from the globe that is supposedly above us..it not right to me,but what do you think ?

  78. Ramesh Babu says:

    https://youtu.be/AOufWlGYFj8

  79. Ugly Nibba says:

    ….what

  80. Ömà Âr Öptimiste says:

    why the rainbow took curved ecxactly ??because there's a dome abouve sky and water exist there too😉

  81. Josh Aquino says:

    this is actually on our exam

  82. Ratikanta Mahapatra says:

    So Rainbow depends on scattering of light or dispersion of light?

  83. Ratikanta Mahapatra says:

    Why violet color bends most?

  84. Humans are Such easy prey says:

    everyone knows its caused by Irish leprechauns

  85. Rosanne Villalobos says:

    Why do we see two rainbows?

  86. wyze17 says:

    This guy sounded really dum .. 😜😜

  87. Sarita Aacharya says:

    Today I saw rainbow at Nepal, kathmandu and I am nepali

  88. Qwecy says:

    This guy is on another YouTube channel

  89. Jesus is Lord says:

    God's Art

  90. Jesus is Lord says:

    You mentioned the question "so what forms the bow of the rainbow?" with no answer

  91. Samuel Maya Montes says:

    Ms Alves we will use this video for your class 😀

  92. izzy yup says:

    Because is the promise from God to noah that forms a rainbow

  93. Vito Corleone says:

    its because of the firmament the dome in the sky …

  94. Courtney Quiles says:

    How about when there are more than 2 rainbows (i saw a picture of up to 8 rainbows at once in different directions)?

  95. LiquidPhase1307 Phase says:

    Wait so whose gold do i have exactly?????

  96. Chan says:

    Gods covenant ❤️

  97. My Quiet Place says:

    Isn’t God Amazing! 😉 Well my friend I have seen complete rainbows not halfway rainbows! In fact I see lots of it ♥️

Leave a Reply

Your email address will not be published. Required fields are marked *