Why Is The Sky Blue?

As sunlight passes through the atmosphere, particles in the air scatter blue light more efficiently than any other color in the light spectrum, creating a blue sky. Learn more about the sky and light in this episode of BrainStuff.

Whether the topic is popcorn or particle physics, you can count on the HowStuffWorks team to explore - and explain - the everyday science in the world around us on BrainStuff.

[audreywagner]

Why, when you talk about the size of wavelengths relative to molecule size, do you indicate wave *amplitude* instead?

[LariosGiveNoFucks]

I have an issue with this. He didn't mention the fact that the human eye is most sensitive to the color blue so we see it better. If smaller wavelengths are reflected more efficiently then doesn't that mean that violet is scattered way more efficiently than blue? The sky isn't necessarily blue to other animals who are sensitive to other lower or higher wavelengths that we can't see.

[BrainStuffShow]

As sunlight passes through the atmosphere, particles in the air scatter blue light more efficiently than any other color in the light spectrum, creating a blue sky. In today's episode of Brain Stuff, Ben from Stuff They Don't Want You To Know explores:

Why Is The Sky Blue?

[SomeOne]

I was lied to. I was told it is because the earth is 80% water so it's reflecting of the water. XD

[narwhool]

Thanks, Ben! My 4 year old had me in a tight spot explaining this one today! 😆

[ashleypatricia]

I noticed someone asked you guys this in the comment section in a previous video, it's exciting to see requests be answered!

[nezarmalibari]

So .. why does sky go orange in sunset? Why not in sunrise?

[jeehoo]

you forgot to mention that it also has to do with the fact that our eyes are designed to be much more sensitive to red, green, and blue. violet light is scattered even more than blue, but we don't see a violet sky because our eyes aren't as receptive to that color.

[Legend]

Question, what color is the sky on our other planets?

[sheikahnayru]

Thank you for making this. I've tried to explain this to my kids but I can't put it in a way that makes sense to them. Now I can just show them this!

[emmanueladeyemi]

thanks a lot. in a more advanced way. out of all the colors in the color spectrum blue gets refracted the most.

[اسماءحماده-هه]

I keep saying wow in every video of you guys Thanks for the information greetings from Saudi Arabia

[free_electron]

Light emitted from the sun as it passes over a horizon will diffuse over a larger area of particles before it reaches your eyes. This means that many shorter wavelengths are scattered and therefore only larger wavelengths reach your retina. Wavelength is determined by inverse of frequency however the white light source frequency is constant. This distance mixed with scattering is why the wavelength shifts from roughly 460nm to about 700nm which is where the red hues exist in visible light.

[yoyogmaayaya]

then why can't we see the sky from space during day time

[carlieclauson]

Wow, its so much fun learning about my boyfriend's favorite color. Give the people what they want - tell us why the ocean is blue.

[LienturAlcamanCurivil]

So what you are saying is that color is a property of the object and not of the perceiver of the light?

[kathillina]

Rayleigh scattering. Gas particles are small that they can scatter smaller wavelength, blue, more efficiently than the red. During day time, the intensity is so high that all you can see is blue light scattered by the gas. At sunrise/sunset, the light has to travel so far that the intensity of the blue light becomes dim because of scattering and you can actually see the red light near and reflecting off the clouds near to the source, the Sun.

[TheBcoolGuy]

I already knew this, I was taught this in 3rd grade or so. This is something that everyone should know in 2013.

[RhinoXpress]

I have learnt more about stuff on the internet then I ever did in school.

[mesoth]

If you remove dust from the atmosphere of Mars, would it be blue too? Or is it actually blue?