In this puzzle, students examine three different sets of salinity data collected from the Hudson River estuary in New York. The puzzle includes data collected along the length of the estuary on the same date; data collected over a span of days that includes before, during, and after a rain event; and finally data collected over a span of several months. Each piece of the puzzle allows students to extract a different insight into the dynamic nature of the saltwater and freshwater mixing of an estuary—how an estuary varies over space, how it responds to regional rain events, and how it varies with the season. This puzzle works well in an Earth science, environmental science, or oceanography class.