The purposes of this study were, based on John Dewey's ideas on experience, to examine how primary students used their own everyday experience and were affected by own and others' experience in science discourse, and to illuminate the implications of experience in science education. To do these, science discourses by a group of six fourth-graders were observed, where they talked about their ideas related to thermal concepts. The data was collected through interviews and open-ended questions, analyzed based on Dewey's perspective, and depicted as the discourse map which was developed to illustrate students' transaction and changing process of students' ideas. The results of the analysis showed typical examples of Dewey's notions of experience, such as the principles of continuity and of transaction and of different types of experience, examples of "the expanded continuity and transaction", and science discourse as inquiry. It was also found that students' everyday experiences played several roles: as a rebuttal for changing their own ideas or others', backing for assurance of their own ideas in individual students' inner changes after discourse with others, and backing for other's ideas. Based on these observations, this study argues that everyday experience should be considered as a starting point for primary students' science learning because most of their experience comes from everyday, not school science, contexts. In addition, to evoke educative experience in science education, it is important for teachers to pay more attention to Dewey's notions of the principles of continuity and of transaction and to their educational implications.