Science education researchers have highlighted how uncertainty can foster meaningful scientific sense-making, supporting students to re-evaluate their understandings of scientific phenomena and pursue deeper causal accounts. However, facilitating whole-class conversations motivated by uncertainty is complex and challenging, calling for further descriptions of the pedagogical work involved for teachers. In this study, we consider recurring pedagogical decision points as a way to get a handle on how teachers orchestrate classroom conversations and improvise to respond to students' reasoning. To examine these decision points, we analyzed five classroom episodes where classroom communities transformed a student's expression of uncertainty into an episode of collective, scientific sense-making. Across these episodes, we found that teachers needed to make decisions around (1) whether to make space for an uncertainty, (2) how to transform an uncertainty into a collective problem, (3) which elements to fix and which to leave open, (4) when and how to support the class to evaluate their accounts, (5) whether to make space for and/or mark new goals. Using detailed analyses of two episodes, along with short descriptions of the others, we illustrate how these decision points emerged, the different choices teachers made, and how these decisions shaped the trajectories of the classroom conversations.