Although existing literature suggests that teachers perceive, mobilize, and leverage resources to support ambitious instruction, less is known about how teachers and students jointly take up resources for co-constructing scientific knowledge. This study examines how teachers and students utilize aspects of practice-oriented curriculum materials and students' everyday experiences as resources to problematize aspects of their scientific inquiry. I present an analysis of how teachers and students employ resources to engage in problematizing as they enact the same lessons from a practice-oriented science curriculum in sixth grade science classrooms. I report on patterns of variability in who leverages what resources to instigate and sustain problematizing, and whether or not the problematizing is in service of or deviates from the curricular intent. I present three representative cases to highlight the tensions that emerge between students' everyday experiences and carefully sequenced curriculum materials. The findings reported here have implications for the design of practice-oriented curriculum materials, teachers professional learning around curriculum use, and the opportunities for redistribution of students' epistemic agency during curriculum enactment.