My students complete an experiment over diffusion of gas molecules. Diffusion is the movement of molecules from a high concentration to a low concentration until equilibrium is achieved. The children make predictions on how many seconds it will take for the room spray to reach them. Then the sweet cinnamon smell comes their way and they record the time in seconds. Using calculators, the work up the class average and look at the variable of location in relation to length of time. Everyone sniff!