Emily finished the catapult, counterweights at 25 lbs. Originally, 35 lbs was tested, but the wood began to splinter so she chose to reduce to 25. Two little 8 lb weights balance out the counterweights.
The catapult's base is 36 in. long, and when standing, the arm is just under 6 ft. It's constructed from mostly recycled wood and iron weights (the counterbalance) borrowed from a neighbor. The arm is attached to the base (when loaded, as shown) using a dowel rod which, when pulled, serves as a trigger. On the opposite side of the trebuchet under the weights, extra wood was added to better support it and prevent it from capsizing after the launch. The sling itself is made from a foam-like material commonly used to prevent rugs from slipping on a smooth surface. While this material would induce friction with the slide board, it also serves to grip the balloon. The sling has two triangles cut out of the side so that it creates a cup shape rather than a rectangle which would better hold the water balloon.