This dissertation explores the integration of Place-Based Scientific Inquiry (PBSI) into science education through participatory design-based professional development for instructors at Sky School, an outdoor education program in southern Arizona. PBSI emphasizes student-centered, inquiry-driven, experiential learning grounded in outdoor contexts. The study investigates how participatory design changes instructors' understanding of PBSI, their confidence in implementing PBSI in Sky School programs, and their self-efficacy as instructors. Using a mixed-methods approach, data were collected through pre- and post-intervention surveys, and artifacts such as facilitator guides. Findings reveal that while instructors developed a deeper understanding of PBSI and increased confidence in student-centered approaches, many continued to rely on conventional understandings of the scientific method as a rigid, linear process, reflecting a gap between conceptual knowledge and practical application. Factors such as path dependency, institutional norms, and limited experience with inquiry-based methods may have contributed to this persistence. The study underscores the need for sustained professional development, emphasizing immersive learning, peer feedback, and ongoing support to help instructors fully embrace PBSI. These results have important implications for designing more effective professional development programs that encourage long-term instructional change and promote inquiry-driven, place-based science education. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]