Despite assurances that he will stay dry, junior Stryker Sinclair fears a soaking from the bucket full of water he swings over his head. “Specifically, [the demo is] a good way to demonstrate that inertia’s what’s keeping the water from falling out,” physics teacher Cinsy Krehbiel said. “We start by talking about how gravity’s pulling the water downward and talk about what’s happening when it’s over their head.” The demo helped illustrate centripetal or circular motion.