Thesis advisor: Katherine L. McNeill / Science education is shifting from a vision of students memorizing facts towards engaging in figuring out the natural world as students build ideas from their own experiences and backgrounds. This shift is hard for teachers. One way to support teachers is curriculum-based professional development, which pairs high-quality instructional materials with professional development to help teachers understand the philosophy of those materials and what that looks like in practice. This three-paper dissertation uses the OpenSciEd middle school field test, a curriculum-based professional development program, as a context to investigate how to support teachers with this shift. The first paper is a quantitative look at teacher surveys taken across the first two years of the OpenSciEd field test. I tracked changes in teachers’ beliefs about science instruction and confidence in implementing OpenSciEd. I used Hierarchical Linear Modeling to identify teacher characteristics associated with differences in those changes. Beliefs and confidence changed initially and leveled out over time, but confidence took longer to change than beliefs. Teachers who had more experience and found the PD more valuable were less likely to hold traditional beliefs and more likely to have higher confidence. The second paper is a conceptual look at practice-based professional development activities focused on one new one: the student hat. Student hat is when teachers engage in science activities while considering ideas and experiences their students might bring to them and sharing those ideas using students’ language. Student hat uniquely helps teachers to consider students’ relationship to the science ideas under discussion and their cognitive and affective responses to reform science instruction. The third paper is a qualitative look at the use of the student hat in one professional development workshop. I engaged in thematic analysis of interviews and video to determine what student hat helped teachers to learn and how. Student hat provided safety for teacher confusion, allowing teachers to learn science ideas. It also helped teachers develop their epistemic empathy for students, helping them to learn about their students and the OpenSciEd instructional approach. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Lynch School of Education. / Discipline: Teacher Education, Special Education, Curriculum and Instruction.