In normal everyday life we come across matter in three states, solid, liquid and gas. They have a fixed shape ... and immediately smell coffee. Why? One reason is moving air currents or convection.

Although the three states of matter are solid, liquid, and gas, not all substances seem to fit perfectly into one of these groups. Take a look at the substance below and see if you can decide whether ...

Students explore the attractions and motion of atoms and molecules as they experiment with and observe the heating and cooling of a solid, liquid, and gas.