This study explores how students use multiple school genres to engage in scientific epistemic practices through their science writing. In a sixth grade science class, three school genres (a Journal Lab Report, Thinking Log, and Final Writing assignment) were integrated into three different Foss^© inquiry units on Levers, Pulleys, and Solar Energy. An important component of the inquiry instruction was an adapted complex problem that accompanied each study unit, given to the student as the unit progressed. The complex problem, in addition to the writing genres, were intended to provide an impetus for the student to continually return to conceptual ideas learned and build upon them throughout the inquiry unit. The movement of students' conceptual ideas in/out of the different genres were examined to better understand how they navigated certain epistemic practices through the different writing opportunities. Findings indicated that writing serves as an important tool that mediates epistemic actions through writing, as evidenced by characteristics present in student writing: tentative treatment of ideas, treating ideas if malleable, raising misaligned ideas, interconnecting ideas, and applying ideas to other contexts. These epistemic actions were enacted through different discursive practices during the reraising of ideas, with each genre providing different writing opportunities. Overall, a more purposeful genre engagement (i.e., genres functioning in parallel with each other as a cohesive system) afforded more authentic, or sophisticated epistemic practices that contributed to contemplating and building onto ideas as knowledge construction occurred.