Have you ever wondered why sky is blue? A lot of other smart people have, too. Let's figure it out!
John Lubbock – A famous liberal politician, Philanthropist and a scientist says about the nature and the Blue sky, "Earth and Sky, woods and field, lakes and rivers, the mountain and the sea, are the excellent school masters and teach us more than we can ever learn from books".
The Sun produces white light, which is made up of light of all colors: red, orange, yellow, green, blue, indigo and violet (ROYGBIV). This was demonstrated by Isaac Newton, who used a prism to separate the different colors of sunlight and so form a spectrum. We know that atoms and molecules re–emit light waves as we shine on them. Likewise even the tiny particles would do the same. The tinier the particle, the higher the frequency of light it will scatter. The nitrogen and oxygen molecules that make up most of the atmosphere scatter high frequencies when energized by sunlight. The re–emitted light is sent in all directions and is scattered.
Most of the ultraviolet light (UV) from the sun is absorbed by a thin protective layer of ozone gas in the upper atmosphere. The remaining ultraviolet sunlight that passes through the atmosphere is scattered by the particles and molecules in it. Violet light is scattered the most, followed by blue, green, yellow, orange, and red, in that order. Red is scattered only a tenth as much as violet. Although violet light is scattered more than blue, our eyes are not very sensitive to violet light. But they are sensitive to blue –– so we see a blue sky!