The Short Answer:
Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered more than the other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
It's easy to see that the sky is blue.
Have you ever wondered why?
A lot of other smart people have, too. And it took a long time to figure it out!
The light from the sun looks white. But it is really made up of all the colors of the rainbow.
When white light shines through a prism, the light is separated into all its colors. A prism is a specially shaped crystal.
If you visited The Land of the Magic Windows, you learned that the light you see is just one tiny bit of all the kinds of light energy beaming around the universe--and around you!
Like energy passing through the ocean, light energy travels in waves, too. Some light travels in short, "choppy" waves. Other light travels in long, lazy waves. Blue light waves are shorter than red light waves.
All light travels in a straight line unless something gets in the way and does one of these things:—
• reflect it (like a mirror)
• bend it (like a prism)
• or scatter it (like molecules of the gases in the atmosphere)