Why is it so hard to get students talking in science class? Who is responsible? Are the students unwilling to speak in class? What kinds of supports are helpful for in-the-moment teaching during classroom discussions in science? We present one high school teacher's facilitation of science discussions while supported by a dialogic discussion structure that was collaboratively developed through professional- development workshops. Our findings provide a real-time teaching tool for teachers working toward integrating inquiry-based science discussions in their classrooms.