the color of the sky

Haven't you wonder why the sky is blue?
Today I want to tell you about the reason why the sky is blue.

First of all, the most important thing to think about the issue is that you understand that light has the character as wave. Because of this character, the scattering occurs.
There are some kinds of scattering. The cause that makes the sky blue depends on Rayleigh scattering. Rayleigh scattering occurs when light injects into a particle whose diameter is shorter than the wavelength of the light. In addition, Rayleigh scattering doesn't change the wavelength after the incidence, and its scattering coefficient is inversely proportional to the four power of wavelength of light. So blue light, the light of short wavelength, scatter well, remained its wavelength. This is why the sky is blue.

By the way, if light injects into a particle whose diameter is as long as the wavelength of the light, Mie scattering occurs. The scattering coefficient of Mie scattering is equal to every wavelength of lights. So the scattered light is white. The white color of clouds due to Mie scattering. Besides when light injects into a particle whose diameter is longer than the wavelength of the light, geometrical optical scattering occurs. Rainbow is made by this scattering.