This inquiry uses teacher-candidate critiques of science lessons as a means of evaluating the effectiveness of an instructor's pedagogical approach to promote teacher candidate understanding of the nature of science (NOS) in a science methods course. Three cohorts of teacher candidates enrolled in a middle-years teacher education program were required to evaluate science lessons for their authenticity based on their developing understanding of the nature of science. The results indicated that the most detailed and accurate analysis of the authenticity of the lessons occurred in the cohort where the nature of science was developed (a) explicitly throughout the course, (b) through the use of exemplars of historical science development, and (c) through a setting that encouraged collaborative consideration of the nature of science.