Question

Why is that the sky is blue in colour?

Answer 1

At a clear day time , molecules of the air scatter blue light more than red by the sunlight . Hence we see sky as blue color. At evening since the blue colored light is scattered , we see red color.

Answer 2

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 orangecolours because the blue light has been scattered out and away from the line of sight.