Background and purpose: The purpose of this study was to investigate and identify the nature and the interrelatedness of pre-service teachers' misconceptions and scientific concepts for explaining dissolving before, during, and after a 5E learning cycle lesson on dissolving, the intervention. Sample, design, and methods: Guided by Vygotsky's theory of concept development, the study focused specifically on the spontaneous, and spontaneous pseudo-concepts held by the 61 elementary pre-service teachers during a 15-week science methods course. Data included concept maps, interview transcripts, written artifacts, drawings, and narratives, and were thematically analyzed to classify concepts and interrelatedness. Results: Results of the study showed that spontaneous pseudo-concepts (1) dominated pre-service teachers' understandings about dissolving throughout the study, and (2) were simply associated with scientific concepts during and after the intervention. Conclusion: Collectively, the results indicated that the pre-service teachers' did not acquire a unified system of knowledge about dissolving that could be characterized as abstract, generalizable, and hierarchical. Implications include the need for (1) familiarity with pre-service teachers' prior knowledge about science content; (2) a variety of formative assessments to assess their misconceptions; (3) emphasizing the importance of dialectical method for concept development during instruction; and (4) skillful content instructors.