A cannon was a cylindrical iron tube that could be filled with gunpowder and lit, to fire a cannonball.
History[]
Cannons were used by soldiers and sailors for inflicting damage to walls and ships from a large distance away. One cannon was fired from Mac the Black's pirate ship directly upward and the cannonball naturally returned (what goes up must come down, after all), destroying the ship.
In Dr. Emmett Brown's video encyclopedia, "H" for Homemade Cannon, Bill Nye demonstrated to the viewers how to create a cannon using simple household items.