ELI5: Why is the sky blue?

Imagine the sun is like a giant lightbulb sending out all sorts of colors, like a rainbow mixed together. These colors travel to Earth.

The air around us is full of tiny bits, like really, really small dust and air molecules. When sunlight bumps into these tiny bits, something cool happens: the colors get scattered around.

Here's the thing: blue and violet light are like bouncy balls; they get scattered much more than colors like red or orange. Think of it like this:

• Red light is like a big, heavy beach ball – it keeps going mostly straight.
• Blue light is like a small, light tennis ball – it bounces all over the place.

At sunrise and sunset, the sun is lower in the sky. The sunlight has to travel through more air to reach us. Because it's traveling through more air, most of the blue light gets scattered away before it reaches our eyes. That leaves the reds and oranges to shine through, giving us those beautiful sunset colors. So, the sky is blue most of the day because blue light scatters more easily, and it's red or orange at sunrise and sunset because the blue light has already scattered away.