A catapult is a type of machine used as a weapon to shoot rocks or other things such as hot tar, that would cause damage to something else. Catapults use weights and levers to send the rocks or other things into the air. They are simpler than other modern weapons and not useful in modern warfare. Catapults were common in the past, especially the Middle Ages. Nowadays catapults are used to study old weapons, and often as fun experiments (usually in physics classes). Sometimes, instead of rocks, pitch or hot tar would be thrown to set the target on fire. catapults were used in the 1600's and are kept in museums.
Often, catapults were set on higher ground or on castle towers to let them shoot farther. They were also used to shoot rocks to break castle walls.