Thermohaline circulation is a foundational concept in introductory undergraduate oceanography courses required for advanced learning in upper-level oceanography courses. Thermohaline circulation describes the density-driven flow of water throughout the world's oceans. This concept is commonly taught using 2D diagrams and animations however, students often struggle with the 3D patterns and connections associated with thermohaline circulation. To remedy this, we sought to present thermohaline circulation in three dimensions to enable students to apply their knowledge and work with physical models. We constructed an interactive physical model of thermohaline circulation which included 3D printed continents and Arduino-controlled LED strips colored to represent global temperature and salinity patterns. We implemented the model as a teaching tool in a large undergraduate introductory oceanography course during the module covering thermohaline circulation. In TA sections, students utilized the model to observe patterns, match depth profiles to different geographic locations, and apply their knowledge to draw their own depth profiles using the model. After completing the in-class assignment, we assessed whether the model helped students understand and apply key concepts from lecture using surveys. Students reported an enhanced understanding of ocean circulation, depth profile interpretation, and processes that cause geographic patterns of temperature and salinity. In addition, students expressed excitement about continued use of interactive physical models used in introductory oceanography courses.