Pressure Gradient

Try out this scaled up variation on the classic “Egg in the Bottle” experiment. Light a match inside a large container (such as this old lava lamp), place a balloon on top and watch as it gets sucked in. Give your students some clues about why this happens and see if they can figure it out (hint: a pressure gradient is created). Then, once the balloon is inside the bottle, ask if they have a suggestion that will get it back out.