During the summer of 2007, the Science Museum of Minnesota carried out a summative evaluation of the Kitty Andersen Youth Science Center's Park Crew program. The purpose of the evaluation was to understand how the youth staff implemented activities in the museum's Big Back Yard and what they learned about earth-surface processes, teaching others, and STEM careers. A mixed-methods design was used to gather evaluative data. Data collection methods included observations of youth presenting activities to visitors and pre- and post-interviews with the youth. A total of 11 youth (sophomore through