Nearly 20 years after the release of The Harvard-Smithsonian Center for Astrophysics’ video, A Private Universe, much research has been done in relation to students’ understanding of space-science concepts and how to effectively change these ideas. However, student difficulties with basic space-science concepts still persist. This article will describe some of the common student misconceptions related to phases of the Moon, introduce a conceptual-change teaching approach, and provide an example of an activity that can be used to address these common misconceptions.