Balloons are always fun but balloons with objects inside are even better! And this particular version has some science thrown in, too.

To start, we wanted to see how an object would move inside a balloon, which means clear balloons are definitely best for this project. Before inflating, add a penny (or similar round metal object). Inflate and tie a knot.

Now give that balloon a shake! You want to shake in a tight, circular motion to get the penny rotating. Even once you stop, the penny will “climb” the walls of the balloon in a circular motion. Travis was thrilled that he could make this work all by himself!

The penny can seemingly defy gravity in this way because as soon as the balloon is spinning, the force of the penny pushes outward. It will stop after a few rotations, but was so much fun for Travis to watch, plus made an echoing bouncy sound.

We intend to try this with other objects in the balloon, too, and see whether they work better or worse than the penny. Here’s the quickest of quick clips: