A few kilometers from the shores of Palm Beach County, Florida, the Gulf Stream current—a remarkable "river" within an ocean—makes its closest approach to land. To help students understand why and how the Gulf Stream flows, they study how Florida's Gulf Stream current could be responsible for the wreck of the Titanic using the 5E constructivist instructional model—Engage, Explore, Explain, Elaborate, and Evaluate—to analyze a single problem: Why wasn't the iceberg that sank the Titanic either dissolved or deflected eastward by the Gulf Stream before the collision?