Building on the "questioning-based discourse analytical" framework developed by Singapore-based science educator and discourse analyst, Christine Chin, this study investigated the extent to which fifth-grade science teachers' use of questions with either an authoritative or dialogic orientation differentially restricted or expanded the quality and complexity of student responses in the USA. The author analyzed approximately 10 hours of classroom discourse from elementary science classrooms organized around inquiry-based science curricula and texts. Teacher questions and feedback were classified according to their dialogic orientation and contextually inferred structural purpose, while student understanding was operationalized as a dynamic interaction between cognitive process, syntacto-semantic complexity, and science knowledge type. The results of this study closely mirror Chin's and other scholars' findings that the fixed nature of authoritatively oriented questioning can dramatically limit students' opportunities to demonstrate higher order scientific understanding, while dialogically oriented questions, by contrast, often grant students the discursive space to demonstrate a greater breadth and depth of both canonical and self-generated knowledge. However, certain teacher questioning sequences occupying the "middle ground" between maximal authoritativeness and dialogicity revealed patterns of meaningful, if isolated, instances of higher order thinking. Implications for classroom practice are discussed along with recommendations for future research.