Classroom discussion can help young children monitor their thinking and share their ideas in order to be understood (Donovan and Bransford 2005). Particularly for children who are not yet reading and writing independently, opportunities to discuss ideas can support engagement and sensemaking during science instruction (e.g., Wright and Gotwals 2017). Discussion can also be used to build coherence for children as they make sense of ideas within a single lesson and across the lessons of a unit. In this article, the authors provide an example of the ways discussion can be used to support coherence within and across science lessons from one kindergarten classroom where the teacher, Ms. Nelson, was using SOLID Start curriculum materials (Wright et al. 2017) to teach about weather forecasting. The SOLID Start project focuses on supporting teachers in enacting ambitious science discourse in their classrooms in order to deepen science learning and promote science language development (Wright and Gotwals 2017). In the project curricular units, children are presented with a puzzling phenomenon and driving question, and then, through a series of coherent activities, they build and revise their understandings of "how" and "why" the phenomenon happens.