Why does sky appear blue?

Explanation

Blue colours of the sky is due to scattering of sunlight air molecules. According to Rayliegh.s law, intensity of scatted light, `Iprop(1)/(lambda^(4))`. So blue light of shorter wavelenght is scatterted much more than red light of larger wavelenght. The blue component is proportionally more in light coming from different parts of the sky. That is why appears blue.