Inspired by a theoretical view of knowledge as a resource, this study explored in detail how a student used knowledge as a resource when she engaged in problem-solving about rocks and what she learned as a result of the practice of solving scientific problems. The context of the study was an inquiry project conducted in an earth science course for preservice elementary teachers offered in a university in Korea. In the project, students were given three different rocks and asked to figure out how each rock had been formed. Data included a student's written report about her inquiry and interviews with her, which were analyzed qualitatively. It was revealed that to solve the rock problems, the student used different types of knowledge as resources--everyday knowledge, personally internalized disciplinary knowledge, and externally retrieved scientific knowledge. The ways the student utilized the knowledge involved three distinctive processes--activation, adaptation, and evaluation of the resources, each of which had subordinate processes of using knowledge--elicitation, search, refinement, combination, selection, and deactivation of the resources. As a result of the scientific problem-solving, the student learned the usefulness and value of knowledge, enhanced previous knowledge, and realized both the limitations of her knowledge and the need for learning new knowledge. Based on these findings, the study proposed a new framework that conceptualized science learning as rediscovery (SLR) and discussed science pedagogies suitable to the SLR framework.