Why Is the Sky Blue?

Why is the sky blue and not purple, green or orange? It's all because of how the Sun's light reaches Earth!

Comprehension Questions:
1. You can separate and see all the colors in white light if you shine sunlight through a specially shaped crystal called a _________.
2. True or False: Particles of dust, pollution, or smoke in the air can cause the whole sky to glow red.
3. Why do we only see blue light when we look up on a sunny day?
4. In what pattern does light travel?