Purpose The current study aimed to identify the distances between a science teacher's intuitive reasoning and researchers’ systematic analysis of various aspects of science classroom discourse. An expert science teacher, given the pseudonym Jake, engaged in self-reflective processes regarding different aspects of classroom discussions to assess the variations and similarities between the teacher's intuitive estimations and the researchers’ data-based reasoning. Design/Approach/Methods Data collection involved in-depth interviews and video recording. Six aspects of science classroom discourse were considered to elucidate the distances: structure, interactional pattern, verbal sequence, typology, cognitive demand, and communicative approaches. Findings The quantitative distances between Jake's estimations and systematic observations of the six aspects of science classroom discourse varied across different aspects of the observed science lesson. While no consistent pattern was observed in the distances, there were increasing and decreasing gaps between the different aspects of science classroom discourse. Originality/Value Considering the contemporary arguments on human cognition and the professional development of science teachers, potential reasons for the differences were explored. Educational recommendations were provided, particularly regarding supporting science teachers’ journey toward becoming reflective inquirers or researcher-teachers.