What causes the color changes?

The color changes happen because things absorb and reflect different parts of light.

Imagine you have a box full of colored blocks, red, blue, yellow, green. When sunlight comes in, it’s like a big mix of all these colors. Now, if something is blue, it's like that block: it takes the blue part and keeps it, but it sends the other colors back out, like bouncing a ball.

So when you look at something blue, you're seeing the light that came back to you from the blue parts. If the object changes color, it means it’s absorbing different parts of light now, and reflecting others, like switching which block it's using in the box.

Sometimes things change color because they're wet, dirty, or heated up. For example, when you put a red apple in water, it might look darker, that’s because water changes how light bounces off it.

Or think of your favorite crayon: if you color with it on paper and then hold it to the sun, sometimes it gets lighter or darker, just like when you shine a flashlight on something and see its shadow change shape.