why is the sky blue?

Answer 1

This question has been asked over 5000 times, and I've prepared a simple answer, without too much science:

The correct answer is that the blue light is scattered by the air molecules in the atmosphere (referred to as Rayleigh scattering). The blue wavelength is scattered more, because the scatteing effect increases with the inverse of the fourth power of the incident wavelength.

OK, but I've known science graduates who don't understand what this means.
Here's my attempt at an answer without too much physics:

I think most people know that sunlight is made up of light of several different wavelengths, and can be split up into the colours of the rainbow. Blue light has the shorter wavelength, and red the longest wavelength.

When sunlight hits the molecules in the atmosphere, the light strikes the molecules and is absorbed. The molecules vibrate and and give off, or 're-emit' the light. Because the molecules vibrate in all directions, the light is emitted in all directions (called 'scattering'). The molecules in the air are much smaller than the wavelength of visible light, but because the blue wavelength is shorter and more energetic, it reacts much more with the air molecules than the red and yellow wavelengths; which tend to pass straight through.

Because the blue radiation is re-emitted from the air molecules in all directions, it seems to us looking from the ground that the blue light is coming from everywhere; hence the sky seems blue.

Near sunset, because of the low angle of the sunlight, we see more of the red and yellow wavelendth passing straight through, hence the colours of the setting sun.

BTW: The sky isn't blue because of a reflection of the sea; its the other way round, although the blue colour of the sea is mostly caused by the water molecules scattering the blue light, in a similar way. This effect is even stronger with ice; which results in the intense blue colour we see if we look down a crevasse in a glacier, or down a hole in the snow made by a ski stock..

For a complete, scientific explqanation, look up 'blue sky' in Wikipedia.

Answer 2

The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.

However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky.some of scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.
As you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The color of the sky near the horizon appears paler or white.=)

Answer 3

the blue colour of the sky is with the aid of Rayleigh scattering. As mild strikes for the period of the ambience, lots of the longer wavelengths bypass quickly by way of. Little of the purple, orange and yellow mild is suffering from the air. in spite of the indisputable fact that, lots of the shorter wavelength mild is absorbed via the gasoline molecules. The absorbed blue mild is then radiated in diverse guidelines. It gets scattered all over the sky. Whichever direction you look, a number of this scattered blue mild reaches you. because you notice the blue mild from everywhere overhead, the sky looks blue.

Answer 4

I am appalled!
This question has been asked at least three times a week for the last year and still only two people know the answer and 9 prove that they will write any crap for 2 points.
If you don't know, you don't deserve points for displaying your ignorance by guessing.

Answer 5

Im not in any way an expert and I'm probably wrong but it's related to the way the light bounces off our atmosphere, and blue light is the heaviest? So blue light bounces toward us so we see it? Sorry I dont really know :S

Answer 6

It's due to the chemical reaction of the gases at the atmosphere.

Answer 7

It's because there is moisture (Water) in the air, and water is blue.

Answer 8

because of the reflection from the ocean. look it up I swear its true.

Answer 9

air acts as a filter

Answer 10

because of the gas in the sky??? i guess......... or the reflection of water.... that's what my cuz told me.........