Every moment of every day (and night), the weight of the atmosphere is pressing down on us—in fact, we call the weight of all that air one atmosphere. What happens if we increase that pressure just a little more? Using a giant trash bag, a vacuum cleaner with a hose, and a willing volunteer, we can decrease the pressure inside an enclosed space, allowing the universe to press in with even more strength than normal. Eric Muller of the Exploratorium Teacher Institute (and two brave volunteers) show how it's done.