If you are wondering what a trebuchet and a catapult are, you should realize that these are ancient weapons that people have used in the past. They are both used in order to destroy the strong walls of the castles and other places that people would like to invade. One main difference is that the catapult will be used to hurl heavy objects but are usually small and the weight of these objects is not too heavy. The trebuchet, on the other hand, is made to hurl very large objects that are also very heavy. This means that the materials that are used to create trebuchets are expected to be stronger because they are meant to hurl objects that the catapult cannot carry.