To build on prior correlational research into personal best (PB) goals and motivational outcomes, an experimental study was conducted to assess the role of PB goal setting in gains (or declines) in students' motivation in science (viz. biology, anatomy, health). The study (comprising N = 71 elementary/primary and secondary school students) applied a pre/post-treatment/control group experimental design to test whether setting a PB learning goal in a self-paced science education program (conducted in a museum context) leads to growth in science valuing and science aspirations. The treatment group (PB goal setting), but not the control group, demonstrated significant growth in science aspirations (but not valuing) between pre- and post-testing. This study provides support for the proposition that PB learning goals are associated with motivational growth in students' lives. Findings also hold implications for museum-based education programs for students.