Ping-Pong Pistol

Materials

A. Paper towel tube

B. Utility lighter

C. Hair spray (aerosol)

D. Duct tape

E. Ping-Pong ball

 F. Knife

How-to:

 ü     Use a short piece of duct tape to seal one end of an empty paper towel tube.
 ü  Cut a hole in the duct tape just large enough for the tip of the utility lighter to fit through.
ü  Release a quick spurt of hair spray into the open end of the tube. You will have to experiment to find the   best amount — there must be enough oxygen in the tube for combustion. Only aerosol hair sprays will work (the type in a metal canister). 
ü  Insert the Ping-Pong ball 1/3 of the way into the tube and then insert the tip of the lighter through the duct tape. 
ü  Spark the lighter. The Piezzo igniter will ignite the propellants and the resulting pressure will quickly accelerate the ball out of the tube.