This article exposes the results of an investigation whose objective was to characterize the development of critical thinking in a group of middle school students in an institution of Bogota-Colombia whose curriculum proposal is guided by precepts of Popular Education. This characterization was based on the research model proposed by Paulo Freire. The methodology was critic-qualitative and included gathering information through field diary and written and audio records made with students. The results and analysis evince improvement in recognizing the student’s context; furthermore, the proper contests of the area Natural Sciences through the thematic research and generators topics proposed by Freire, and through which valuable items are recognized in the construction of empowered subjects of their educational process, and the dynamics of their community from the scientific explanation of the phenomena of their environment