在以下頻道推出： Tubi
第 1 季，第 3 集: Phil starts with a Popsicle stick catapult. Then he uses everything he knows about elastic energy to build a full-size catapult that hurls pumpkins! Plus, a maxed out paddle wheel boat and a historical re-enactment (sort of) of how catapults were used in medieval days.
Educational · 2015年9月14日 · 21 分鐘