For the past two years, the Foundations in Physics and Mathematics (FPM) summer program has been held at Indiana University in order to fulfill two goals: provide additional physics and mathematics instruction at the high school level, and provide physics graduate students with experience and autonomy in designing curricula and teaching courses. In this paper we will detail changes made to the program for its second year and the motivation for these changes, as well as implications for future iterations of the program. We gauge the impact of the changes on student performance using pre-/post-test scores, student evaluations, and anecdotal evidence. These data show that the program has a positive impact on student knowledge and this impact was greater in magnitude in the second year of the program. We attribute this improvement primarily to the inclusion of more inquiry-driven activities. All activities, worksheets, and lesson plans used in the program are available online. (Contains 3 tables.)