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.Their prediction is based on their location in the room in comparison to where the spray is diffused. Then the sweet cinnamon smell comes their way and they record the time in seconds. Using calculators, they work up the class average and look at the variable of location in relation to length of time. Everyone sniff!