The NGSS defines new standards that require prospective teachers to learn content knowledge in new ways and this will be important to their instruction. The present study assesses the fundamental physics knowledge gained by prospective teachers following an introductory course in middle school physical science. The study examines prospective science teachers conceptual understandings of the atomic and molecular theory, Newtons Laws of Motion, and the Energy concept (critical components of subject matter knowledge for teaching). Two conclusions from this study are evident in light of the reforms offered by the NGSS. The prospective teachers who participated in this study have not attained a robust understanding of the particulate nature of matter and kinetic molecular theory. Pre-service teachers in this study have not developed a deep conceptual understanding of the basic physics concepts necessary to guide novice students in their study of the foundational physical science concepts.