A 40 mm ping pong ball is loaded into a 1.5 inch PVC pipe and rolled to one end. Packing tape is applied to each end of the tube and a vacuum is pulled inside the tube. When the tape near the ball is ruptured, a slug of air pushes the ball along the tube. With atmospheric pressure doing the pushing, and no air resistance, the ball leaves with a speed near that of sound!
The ball can be directed to targets, a cardboard box, or a rack of empty soda pop cans.
Questions:
Would this work on the moon? (ie. in a vacuum?)
What does the speed depend on?
Would the speed be higher or lower at the top of a mountain?
