The purpose of this study was to examine third-grade students' ideas about the lunar phases prior to and following an instructional period designed to promote students' conceptual change. Four third-grade students enrolled in an elementary school near a large midwestern university participated in this study. Qualitative methods of interviewing and observation were used to identify students' conceptions of the lunar phases. Analytical induction was used to analyze data collected in the forms of researcher notes and transcriptions of audio-and videotaped interviews and lessons. The results of this study indicated that students held individual views that were scientifically accurate; however, they also held conceptions that were scientifically inaccurate. In addition, the results demonstrate that students are capable of making conceptual changes; however, they also continued to hold views that were inconsistent with the scientific perspective.