The sky blue ...!!!

why the sky is blue???

~>first, you need to know that light with shorter wave (in the light spectrum) is in the blue region, with the spread angle greater than the direction of the longer wave, because this size is approaching the size of smoke particles.

then when we look to the sky, we see a light blue is mixed by air from every directions. Thus, the sky appears blue even though there are additional light from the sun.