Why is the sky blue and what determines its color?

The sky is blue because light from the sun travels through Earth’s atmosphere and scatters in different directions, like how a ball bounces around when you kick it on a bumpy floor.

Imagine you're playing with a water balloon. When you throw it, the balloon hits the ground and bounces up again. That's scattering, the light from the sun acts like your water balloon, bouncing off tiny particles in the air called molecules, which are like invisible bumps on the ground.

Now, think of sunlight as a rainbow, it has many colors, like red, yellow, green, and blue. When the light hits these molecules, blue light bounces around more than other colors because its waves are shorter. It's like how a small ball (blue) bounces more easily on bumps than a big one (red). So blue light fills the sky from all directions, making it look blue to our eyes.

When the sun is low in the sky, like at sunrise or sunset, the light has to travel through more air, it’s like walking through a longer hallway with more bumpy tiles. This makes the blue light scatter even more, and other colors become more visible, making the sky look orange or red, just like when you shine a flashlight through colored cellophane.