This article describes an activity in which upper elementary students created “stream profiles” of an imaginary aquatic environment using science, mathematics, and simple materials. After the simulation, they applied what they learned during a field trip to a nearby stream. The children truly enjoyed this introduction to fieldwork skills, and the experience provided them with an “inside look” into the careers of limnologists (scientists who study freshwater systems) and oceanographers, who need to map the depths of bodies of water to understand sedimentation rate, current flow, geology, and safety.