Why Is the Sky Blue?

We see a blue sky, because of the way the atmosphere interacts with sunlight.

White light, including sunlight, is made up of many different colors of light, each with its own corresponding wavelength.

Several different things can happen when this light encounters matter.

For instance, if sunlight passes through a transparent material, such as water, those light waves will refract, or bend, because light changes speed as it travels from one medium (air) to another (water).

Prisms break up white light into its constituent colors, because different wavelengths of light refract at different angles — the colors travel at different speeds — as they pass through the prism. read more

full story