======Ping Pong Vacuum Cannon======


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====Summary====                   
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====Procedure====  
  -Refer to links below for construction, setup, and operating instructions.




====Links==== 
Supersonic ping pong balls...vacuum and compression cannon combination. PART TWO - Homemade Science with Bruce Yeany: 
{{youtube>nIL3HN4PQlI?}}\\

Supersonic Ping Pong Balls Launcher?! Purdue University Physics Experiment - Purdue University: 
{{youtube>YYNCGZCul1Q?}}\\

📄 Vacuum Cannon Drives Ping Pong Ball at Supersonic Speed - Bill WW: [[https://www.instructables.com/Vacuum-Cannon-drives-ping-pong-ball-at-supersonic-/]]\\

📄 Vacuum Cannon - Harvard: [[https://sciencedemonstrations.fas.harvard.edu/presentations/vacuum-cannon]]\\


====Variations====
  * Use high-speed video (behind a protective shield) to compare acceleration and exit speed under different vacuum levels.  
  * Replace destructive targets with soft catch boxes (e.g., dense foam) to capture the ball for momentum studies.
  * Convert to a purely observational demo behind a transparent ballistic barrier and use a photogate or timing screens for non-destructive speed measurement.



====Safety Precautions====
  * Treat this as a high-energy projectile launcher; it can be as dangerous as a firearm at close range.  
  * Use a certified ballistic shield in front of the muzzle and a solid backstop behind the target; keep all people strictly out of the line of fire and behind barriers.  
  * Wear ANSI-rated eye/face protection and hearing protection; enforce PPE for everyone in the room.  
  * Operate only in a controlled lab space with remote triggering; never place any body part in front of or behind the tube once under vacuum.  
  * Use schedule-rated pressure/vacuum-compatible tubing and fittings; inspect for cracks and never exceed manufacturer limits.  
  * Evacuate and vent slowly; unexpected ruptures can occur during pump-down. Keep hands clear of seals and use long tools to initiate rupture.  
  * Secure the tube to a rigid mount to prevent recoil or whipping; restrain vacuum hoses and cables.  
  * Prohibit improvised targets (glass, batteries, aerosols) and eliminate ricochet hazards.  
  * Establish a written range protocol (clear range calls, countdown, misfire procedures) and maintain a safety perimeter.  
  * Supervision by qualified personnel is mandatory; follow all institutional and legal requirements for high-energy demonstrations.




====Questions to Consider====
  * Why does removing air from the tube dramatically increase the achievable speed? (It eliminates drag inside the tube, so the net force is roughly atmospheric pressure times ball area.)  
  * What ultimately limits the maximum speed? (Finite pressure differential, membrane rupture dynamics, ball/tube leakage and deformation, and speed of sound constraints at the muzzle.)  
  * How could you measure exit velocity safely and accurately? (Photogates, break-beam timing screens, or a ballistic pendulum behind shielding.)  
  * Why does the ball slow rapidly after leaving the tube? (Air drag increases dramatically; Reynolds number and compressibility effects dominate in free air.)  
  * How would weaker vacuum, different membrane materials, or a longer tube change performance? (Lower vacuum reduces net force; tougher membranes delay/alter pressure rise; longer tubes allow more acceleration up to drag/leak limits.)