Teaching and learning are analyzed for evidence within the context of the relationship between development of students' thoughts and the manner knowledge is organized and taught in the classroom. Analyses are based on discourse of Historical and Cultural Theory authors about day-to-day and scientific concepts and on the relationship between thought and language. Empirical data were obtained during the project's execution with students of the fourth grade of the public primary school in the municipality of Maringá, Brazil. The project included themes on food production and conservation, industrialization and technology. Conceptual learning was undertaken during the execution of the project based on the assumption that teacher's mediation must exist so that previous knowledge could be transformed into scientific one. In the teaching episodes analyzed in current research, the movement of students' thoughts, triggered by the situation-problems that helped them in their trajectory between spontaneous and scientific concepts, has been perceived.
teaching; learning; conceptual learning; primary teaching