Also on these boards
Mandy would like this: popsicle stick bracelets: boil in water for 15 minutes then place in cup to dry~this is cool!
Build the catapult in different sizes, or with different rubber bands, or pencils of different length - discuss the changes each variable makes to the resultant motion of the projectile. Demonstrate circular motion and rotational KE. Based on the relevant principles, have the kids design and build other working models of catapults. Here are some ideas.
DIY Popsicle Stick House... Maybe I could make it into a stable for my little ponies? (Good thing Christmas is a while away... Plenty of time to work it out)