Developing knowledge about science instruction is critical for preservice teachers. This study explores how 79 elementary preservice teachers perceive the relevance and importance of assessment task scenarios designed to elicit information about content knowledge for teaching (CKT) about matter and its interactions--a foundational topic for teaching physical science. Participants completed practice-based assessment tasks that described teaching scenarios about elementary science teaching and that addressed five matter topics: properties of matter, changes in matter, the model of matter, materials, and conservation of matter. We aimed to explore how relevant preservice teachers felt these task scenarios were to their teaching experience and how important knowing how to answer these tasks was for the work of elementary teachers. Findings suggest that preservice teachers tended to recognize the centrality of these task scenarios for the work typically done in elementary classrooms, even if they do not report having firsthand experience with the content and practices represented in the scenarios. Moreover, participants tended to provide a general rationale about why these scenarios were important for the work of teaching science, but a limited number of responses made explicit connections between a task scenario and the specific instructional practice related to elementary teachers' work. This study poses implications for the use of CKT tasks in elementary education programs.