Supersonic Ping-Pong Ball
Xander Naumenko, Jonathan Shim
Lord Selkirk Elementary
Floor Location : J 014 D

We wanted to see if we could make a Ping-Pong ball go at supersonic speed. We created a Ping-Pong cannon by vacuuming out all of the air in a sealed tube with a vacuum pump and then poking a hole in a seal on one end, causing the air to rush in and accelerate the ball. We fired the cannon into a ballistic pendulum and then measured the height it reached. We did the experiment with 3 different lengths of pipe. Then, by factoring the laws of conservation of energy and conservation of momentum together, we calculated the speed of the ball and extrapolated the length of pipe needed to go at supersonic speed. Our hypothesis was that with a long enough tube, you could, theoretically, get a ping-pong ball to travel at the speed of sound. Our end result was that yes, the longer the tube, the faster you can shoot a ping-pong ball and yes, you can launch a ping-pong ball at the speed of sound if your pipe length is approximately 3.2 metres. We got inspiration from Mythbuster episode 215 : supersonic ping-pong ball/ice cannon. They tried to see if they could get a ping-pong ball cannon to inflict lethal damage, and we changed the experiment to see how fast the ping-pong ball goes.