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

The sky is blue because light from the Sun travels through Earth’s atmosphere and scatters in different directions, kind of like how a ball bounces off a wall.

Imagine you're playing with colored balls in a big room full of soft, fluffy pillows. When you throw a red ball into the room, it bounces around randomly, but blue balls bounce more because they’re smaller and lighter. That’s what happens with light: blue light is scattered more than other colors, so we see mostly blue when we look up at the sky.

Now imagine you're looking at the sky during sunset, like watching the Sun go to sleep behind a hill. The light has to travel through more of Earth’s atmosphere to reach your eyes. That means it goes through more pillows, if you will. All that extra bouncing makes red and orange light stand out more because they are bigger and heavier, kind of like how a heavy ball would roll farther than a light one.

So during the day, we mostly see blue, but at sunset, the sky looks red or orange, it’s just the way light travels and bounces around!