In this study, the author investigated how four science teachers employed model-based teaching (MBT) over a 1-year period. The purpose of the research was to develop a baseline of the fundamental and specific dimensions of MBT that are present and absent in science teaching. Teacher interviews, classroom observations, and pre and post-student assessments were gathered. Using a Generate-Evaluate-Modify framework as a theoretical guide, the author identified three fundamental aspects of MBT that were not apparent in an analysis of the teaching methods. Drawing on these findings, the author hypothesizes the consequent impact of the absence of these aspects on MBT on students' experiences and performance in science. Implications for core science teacher professional development activities on MBT are discussed.