The Trebuchet works by using the energy of a raised counterweight to throw the projectile. Initially, the sling, which has a pouch containing the projectile, is placed in a trough below the axle, which supports the beam. Upon releasing the trigger, the sling and the beam swing around toward the vertical position, where one end of the sling releases, opening the pouch and propelling the projectile towards the target.
(There is an interesting online Trebuchet Challenge Game.)
Catapults were used as a key siege weapon against castles and fortified walled cities. As well as attempting to breach the walls, incendiary missiles could be thrown inside. We had made some before with mousetraps, but I thought it was time to make some new ones. I saw some directions for making some that looked easier than the mousetrap ones on Almost Unschoolers. (You can even sneak in a lesson on the physics of it, if you want to.)
This catapult is made from a spring-style clothespin, a craft stick, a small scrap of wood and a cap. Almost Unschoolers used a milk bottle cap, but we don't get gallon milk jugs, so I used spice bottle caps and they worked fine. Any small, shallow cap would probably work. You will also need some sort of glue. Almost Unschoolers pictures Elmer's School glue, but I found a glue gun glued solidly and quickly, which is better for the anxious little boys waiting to play. Glue the clothespin to one end of the scrap of wood.
Glue the craft stick to the top of the clothespin.
Glue the plastic cap, hollow side up, near the end of the craft stick, but not right at the end as you will need to leave a little room for fingers to press it down.
Wait a moment until the glue is dry. Place a pompom (or two or three) or a marshmallow into the cap. Push down on the craft stick...
...and let go!
My boys played for quite a long time with them.
I am sure they will dig out the plastic knights and the castle or make some of their own in order to use their siege engine for more history play.
(Lady Chadwick's blog has some versions that they have made through an interesting experimental process.)