Living in NW Colorado, the balloon stretched over a can actually does shoe significant movement this time of year! However, using weather maps with the "contour" lines of pressure bring home the usefulness of the concept a bit more with my juniors and seniors--I teach high school students. Sorry I don't have any other great ideas! I will see what else I can find! Bev -- Bev DeVore-Wedding Meeker High School 550 School Street, P.O.Box 159 Meeker CO 81641-0159 970.878.9070 ext. 330 “It is impossible to teach without the courage to try a thousand times before giving up." Paulo Freire