During two academic years, in an under-graduated module, each student was required to write reflective statements weekly about what they have learned. The major concern was to promote learning about science education developing critical thinking. A set of guidelines intended to enhance systematically and explicitly critical thinking were given. According to some criteria, a content analysis of the set of statements written by 40 Portuguese students was performed. The results show that students developed critical thinking and made a progressive attempt to establish links between different science education research areas. The students also revealed a progressive easiness in identifying the implications for science teaching of the theoretical issues. Yet, teacher educators gained feedback that allowed them to improve their practices. Some implications of the study can be drawn for science education.