Does a sensori-motor experience help a physics student understand the movement of molecules in solids, liquids, and gases? Students aged 9-10 were given either traditional demonstrations of solids, liquids, and gases and the variation of molecular motion with temperature (iconic presentation), or they were involved in physical activities as they pretended to be molecules (enactive presentation). Concludes that the enactive group did significantly better in subsequent tests on the subject. (Author/MM)