why is the sky blue?

I always wondered why the sky is blue, i know the water is blue because of the sky, but i never new that it was because of the molecules in the air scattering blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.The white light from the sun is a mixture of all colours of the rainbow.