Science experiment

Ds and dd were doing a mini-unit on weather and we did an experiment on pressure. You are supposed to take two toilet plungers and stick them together. With a child on each end, they are supposed to pull in opposite directions. The toilet plungers we bought did not stick together as the rubber bottoms were not cut smoothly. The kids got the general idea, but the effect of the experiment was hampered by the poor quality of the plungers.