WHY IS THE SKY BLUE?

It's easy to see that the sky is blue. Have you ever wondered why?

Light is combination of seven colors of light Red, Orange Yellow,Green, Blue, Indigo and Violet. The wavelength decreases from Red to Violet though speed is same which is approximately 3,00000 km/s. 

When white light shines through a prism, the light is separated into all its colors. A prism is a specially shaped crystal which breaks the light into its constituent spectral colors. 

Prism Experiment

These seven colors combined together makes the light white in color. Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it has smaller wavelength. This is why we see a blue sky most of the time.

Now, A BIG Question Arises: 

WHY SKY IS NOT VIOLET?

As according to prism experiment Violet deflects more than Blue  and Violet have shorter wavelength than Blue.

The reason behind this is in our eyes receptors. The wavelength of Blue light is 450 nanaometers and the wavelength of Violet is 400 nanometers. A nanometer is 1 billionth of meter. 

A human eye a sensitive to light between roughly 380 nanometers to 740 nanometers. Hence our eyes are less sensitive to violet and we see Blue Sky.