Density involves the amount of a material in a certain volume. When a material changes phases, it changes in density in a predictable way as the amount of material stays the same but the molecules get farther apart or closer together. Water has solid and liquid states that do not follow these predictions of density in the phases of matter. What does that mean about the densities of the phases of water? The solid state is the most dense, followed by the liquid state, then the gas state. The solid state is more dense than the liquid state. The liquid state is more dense than the solid state. The gas state is the most dense, followed by the liquid state, then the solid state.