Why is the sky blue and what causes sunsets to be red?

The sky is blue because light from the Sun travels through Earth’s atmosphere and scatters in all directions.

Imagine you're playing with a bunch of tiny, colorful balls, each one represents a particle in the air. When sunlight comes in, it's like a rainbow of colors, red, orange, yellow, green, blue, indigo, violet. But these tiny particles don’t let the colors pass through evenly. They scatter the blue and purple light more than the others. So that blue color goes everywhere, making the sky look blue to us.

At sunset, the Sun is low on the horizon, so its light has to travel a longer path through Earth’s atmosphere. It's like walking across a room, the farther you walk, the more things get in your way.

As the blue and purple light gets scattered away along that long path, the red and orange colors make it all the way to your eyes. That’s why sunsets look red, orange, or even pink, like a fruit smoothie!

Sometimes, if there's smoke or dust in the air, those can also change how the light looks, making sunsets extra colorful!