Ping-pong gun fires balls at supersonic speeds
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When a paddle tries to return a supersonic ping-pong ball -- the paddle loses! (Photo: Mark French)
Supersonic ping-pong gun being assembled (Photo: Mark French)
Schematic diagram of the supersonic ping-pong gun (Image: Mark French)
How a de Laval (convergent-divergent) nozzle works (Image: Wikipedia)
Dimensions of the de Laval nozzle used on the supersonic ping-pong gun (Image: Mark French)
de Laval nozzle being joined to the pressure vessel (Photo: Mark French)
High-speed photograph taken while measuring the muzzle velocity - note the turbulence behind the ball (Photo: Mark French)
Article Summary
The fastest serve ever recorded by a ping-pong player moved at about 70 mph (113 km/h). Professor Mark French of Purdue University's Mechanical Engineering Technology department and his graduate students, Craig Zehrung and Jim Stratton, have built an air gun for classroom demonstrations that fires a ping-pong ball at over Mach 1.2 (900 mph or 1,448 km/h). As the picture above shows, that's fast enough for the hollow celluloid balls to blow a hole through a standard paddle.
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