There is widespread agreement that emotions play a critical role in informal science learning, yet little is known about the emotional experiences of children in informal science learning environments. This study aims to address this challenge by exploring the relationships among emotional, behavioral, and cognitive engagement in a science museum exhibition. Participants included 88 middle-school aged children who explored a exhibition focused on ratio and proportion at the Museum of Science, Boston. A variety of measurement techniques were used to assess children's emotional, cognitive, and behavioral engagement as they explored the exhibition. Findings point to the importance of feelings of struggle in this context, and the potential for experiences of struggle to support deep cognitive and behavioral engagement.