Bart experiments with and researches the Coriolis effect after losing to Lisa in a "bathroom products race." Note that the plumbing setup also affects the way water swirls in a drain, so the Coriolis Effect is not the only factor at play.
This clip illustrates ocean currents and the factors that affect them. It mentions that there are both surface currents and deep sea currents, which make up 90% of the ocean's water. It also explains how the Earth's rotation causes phenomena such as the Coriolis Effect.