A few weeks ago in tech, we made catapults. I made one of my own design and it was pretty simple. The materials that I used were popsicle sticks, rubber bands and a bottle cap. I got a bouncy ball and used that for my material that I was going to catapult. This was all based of what we learned before about a lever, there is a effort arm which is the input, a load arm which is the output and the fulcrum. I did the experiment in my living room because it is one of the biggest rooms and the ball went more than halfway across. Overall, I think that it went very well. The only thing that I would change is I would make sure that it was easier to pull back the load.