Environmental negotiations and policy decisions take place at the science–policy interface. While this is well known in academic literature, it is often difficult to convey how science and policy interact to students in environmental studies and sciences courses. We argue that negotiation simulations, as an experiential learning tool, are one effective way to teach students about how science and policy interact in decision-making. We developed a negotiation simulation, called the Mercury Game, based on the global mercury treaty negotiations. To evaluate the game, we conducted surveys before and after the game was played in university classrooms across North America. For science students, the simulation communicates how politics and economics affect environmental negotiations. For environmental studies and policy students, the mercury simulation demonstrates how scientific uncertainty can affect decision-making. Using the mercury game as an education tool allows students to learn about complex interactions between science and society and develop communication skills.