A cannon is a weapon that uses an explosive charge inside a heavy, metal barrel to force out a heavy metal ball called a cannonball at high speed. Cannonballs usually weighed around 19kg.

Cannons are rarely used today, however when they were commonplace they were extremely dangerous. They were particularly useful in battles between ships, as a cannonball could easily go through the side of a wooden ship, which would make it take on water and sink.