(2B30.70) Ping Pong Cannon
A ping-pong ball is placed at one end of a 8-foot long tube which is sealed off at both ends. The air is evacuated using a vacuum pump from the tube. The seal at the end of the tube near the ball is ruptured using a knife. The air rushes in, pushing the ping-pong ball down the tube. The ball accelerates to more than half the speed of sound, bursting through the seal on the other end of the tube.