Why does a balloon expand when it gets warm?
Balloon's Sunny Secret
Why does a balloon expand when it gets warm?
Leave a balloon in a sunny window and something a little magical happens. It doesn't pop. It doesn't move. It just... swells a tiny bit fatter, all by itself. No one pumped it. So who did?
The secret is inside the balloon, and there are millions of them. Air is made of teeny invisible specks called molecules. They're far too small to see, but they're always there, zipping around inside that stretchy rubber bubble.
