The difference is mostly due to the fact that air is a gas ... solid but has a lower density than water, which is why wood generally floats on top of water. Liquid mercury has a very high density ...

Through investigating solids, liquids, and gases and the phenomena of dissolving, evaporation, and condensation, students develop models to investigate matter at the particle level.

After viewing a model of salt, students help develop models for the processes of salt dissolving, water evaporating to form a gas ... component of the 5-E lesson plan. Remind students that they have ...