Preservice teachers often enter teacher education programs with naïve views about mathematics and science as well as the various domains of knowledge needed for effective teaching. A significant body of research has demonstrated that teacher knowledge is multifaceted and consists of both subject matter knowledge and pedagogical content knowledge. In this study, a cohort of preservice elementary teachers participated in an activity involving two components of subject matter knowledge (factual/procedural and conceptual). Analysis compares the preservice elementary teachers' confidence in their understanding of and ability to teach factual/procedural and conceptual knowledge in mathematics and science. Qualitative analysis of a discussion following the activity provides insights into the quantitative findings.