Have you ever noticed that it’s easier to float in seawater than in the bath?

Every material in the universe is formed of tiny molecules. Molecules are arranged differently in each material. “Density” describes how tightly a material’s molecules are arranged. Materials with tightly packed molecules are denser than materials with loosely packed molecules. Density affects whether things float or sink. For example, a metal coin will sink in water as the molecules are tightly packed together – the coin is denser than water. A cork floats on water because the molecules are more spread out (corks have a lot of air inside them) – the cork is less dense than water.

In this experiment, we will make a liquid rainbow by making solutions of different density.