why is the sky blue?

Answer 1

http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html perfect site for quick answers and good illustration to explain incase you are a visual learner

Answer 2

This is a commonly asked question. and the correct answer is that the molecules in the air scatter the blue wavelength of the spectrum (known as Rayleigh scattering), allowing the other wavelengths to pass through.That is fine, but I know science graduates who still don't understand this explanation.
Here is my explanation, with a limited amount of physics involved:

I think most people know that white light is made up of a spectrum of different colours, which can be broken down with a prism (or in a rainbow), showing a range of different colours, from red to blue. Technically, the red light has the longer wavelength, and the blue the shorter wavelegth (there are other wavelengths such as infrared and ultraviolet that our eyes cannot see).

When the light passes through the atmosphere, the red and yellow wavelengths pass right through, because their wavelength is larger than the size of the air molecules, and they don't interact. However, the blue wavelength is just the right size to hit the air molecules, and they bounce off in all directions (ie, they are scattered). (To understand this, imagine you are walking through a cloud of fine mist. It might be a bit unpleasant, but the tiny mist droplets are too small to cause you to slow down, and you can pass straight through. However, if you were walking through a packed crowd of people the same size as you, you couldn't pass through without colliding with and bouncing off some of the people. An elephant however, would have no trouble passing through).

That is why, when we look up at the sky, the sky seems blue, and the blue colour seems to be coming from all directions. We are seeing that scattered blue light (closer to the sun, the blue colour is not as strong. because of the red and yellow light passing straight through). The air molecules act like a sort of filter, letting the red and yellow wavelengthe straight through, but causing the blue light to bounce around. When the light reaches us on the ground, we see the combined effect of the red and yellow wavelength light passing straight though, mixed with the blue light reaching us from the sky.

If you see a sun beam passing through a narrow space into a dark room (eg through a slit in a blind) it will look more yellow, because it lacks the scattered blue part of the spectrum.

That is not a scientifically accurate explanation, but is the best explanation I can think of, without using physics.

Answer 3

A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight. The white light from the sun is a mixture of all colours of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colours and so form a spectrum. The colours of light are distinguished by their different wavelengths. The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between. The three different types of colour receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our colour vision.

Answer 4

the sky is blue due to greater scattering of blue wavelength of sun light. if scattering be represented by i and wavelength by x then i is proportional to x^4 . blue haslonger wavelength than other visible colours and in the spectrum of white light the intensity of blue light is greater than that of violet and indigo . so the sky appears blue to us .
p.s. it is a general misconception that the sky is blue due to reflection of the sea. in fact sea is blue due to reflection of sky.

Answer 5

reflection of light that bounces back to the sky causes it to be what we see as blue

Answer 6

because god made it that way.

no WAIT!

maybe beause the ocean is blue, so the sky is blue?

Answer 7

Blue colored light has very less wavelength, and so scatters fasters than any color.

Answer 8

God chose it that way! Reflection of the ocean..

Answer 9

Same reason it is dark at night, light and shade.

Answer 10

PLEASE PEOPLE - learn to use the "search" feature above. This question is asked every day.