Simple machines these are not. The eighth graders began studying physics and simple machines before spring break. Their assignment at the end of the unit was to build a working catapult using only rubber bands, mallets or human appendages as the “power source.” The students had to understand the difference between first, second, and third class levers in order to build their catapults. Bragging rights went to the longest wiffle ball tossed by a team catapult.