Soap bubbles float on a cushion of carbon dioxide gas.

As René Descartes (almost) said, "I sink, therefore I am."

Make your own heat waves in an aquarium.

A balloon acts as a lens to focus sound.

Objects change size when heated or cooled.

A dipping bird seems to go forever—but it's not perpetual motion.

Construct a simple hydrometer to compare the densities of solutions.

Create and examine an ice balloon.

Watch the rise and fall of hot and cold fluids.

This density column always returns to its original three layers.

Levitating magnets show how the Earth’s atmosphere stacks up.

Make a reverse Cartesian diver.