What does learning look like in the free-choice environment of science museums? How can we assess learning in museums? The first half of this presentation will describe the Exploratorium’s research and evaluation program. Joshua Gutwill will discuss goals of various research projects, methods and technologies for assessing visitors’ behavior, conversations and experiences, and briefly touch on some of our studies’ results. In closing, Ken Finn will provide an overview of the Exploratorium’s mission and educational philosophy while touching on the exhibit research and development process.