All three trials for our trebuchet. In the third one, you can see a pink material on the slide board, which we put to try and reduce friction.

(The material in question)

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.

Finished cutting all the wood and constructed the base, then finished up the towers.

Cutting all the wood-- and the finished pieces!

Digging around for recyclable materials behind Jackie's Grandpa's shed.

Doing research and looking at design plans.

Meetings

Date	Work Accomplished	Members Present
5/13	In the computer lab we worked on researching the physics aspects behind the trebuchet and created a blog.	Jackie & Emily
5/15	We met to go over designs and begin gathering materials. We found scrap materials at Jackie’s Grandparents’ house and in Emily’s garage. We began cutting wood on this day.	Jackie & Emily
5/16	We actually started constructing the trebuchet and cut wood as needed. We built up to the towers.	Jackie & Emily
5/18	Emily finished construction of the trebuchet as Jackie was out of town. Some trials were launched and adjustments to the counterweight were made.	Emily
5/19	We met up to film the three trials needed. To reduce friction, we tried using a different, silkier material for the sling, but after no improvement was reached, we returned to the previous material. The trials averaged a distance of around 37 feet.	Jackie & Emily

This is a log of the times Jackie and Emily worked together on this project. The meetings lasted for several hours for the construction part of building the trebuchet.