Density Tower
Five liquids that refuse to mix, stacked heaviest to lightest. Drop in a cork, a grape, a bolt or a coin and watch each one sink until it meets a liquid denser than itself.
How it works
Density is mass divided by volume — how much stuff is packed into a given space.
Liquids that do not mix arrange themselves by density, with the heaviest at the bottom.
An object sinks through any liquid less dense than itself and floats on the first liquid that is denser, so it parks at exactly its own density level.
Fun facts
Honey is about 1.4 times as dense as water; oil is about 0.9 times.
A steel ship floats because its hull encloses a huge volume of air, lowering its average density.
Ice floats because water is one of the rare substances that expands when it freezes.
Density is why hot-air balloons rise: heated air is less dense than the cool air around it.
