The carbide cannon was invented in 1907 and continues to this day as the safest noise maker available. Carbide reacts with water to form acetylene gas and when mixed with oxygen inside the cannon's chamber it creates a small, localized explosive atmosphere. The system is inherently safe in that the volume of the toy controls the amount of gas that can be exploded. "The cannon can throw a projectile about as far as you can kick a hat full of bricks."
Early cannons were rather complicated using external gas generators and electric apparatus for ignition. In 1915, Dr. James H. Wily, a Lehigh University professor, greatly simplified the design.
Wily moved the gas generation to the inside of the cannon. The cannon body incorporates a water sump below the chamber. At the rear of the cannon is a breech opening. The breech block was fitted with a little spoon that held the correct amount of carbide. When the breech block was inserted into the cannon and turned 1/4 turn to lock it in place, the carbide was tipped into the water and the gas was formed. A flint wheel in the breech block was then used to ignite the charge producing a sharp report.
After firing, the shooter removes the breech block and blows through the opening to replace the oxygen that was used in firing. The cannon is now ready to be loaded and fired again.
See also: Bangsite
See also: Calcium Carbide