We carried out an action-research program in Spain based in metacognitive reflection with four science teachers in a secondary school during 2002/03 and 2003/04. During the study, the participating teachers analyzed their own students' alternative ideas on energy, and the teaching methods they themselves used as were observed in the videos of their classes. They also planned new teaching units. In the article we will focus on the case of one experienced teacher named Raquel, and show how her teaching models and her students' ideas on energy evolved during this program. The results showed that the teacher's reflection on their students' commonest alternative ideas and on her own classroom teaching led her to plan new teaching units which took those alternative ideas into account, and included new strategies, resources, and activities during the second year of the study. However, the evolution of Raquel's global teaching model to inquiry/ constructivist was not enough for improving student learning in various concepts of energy, so more work is needed not so much in their general teaching model, but in their pedagogical content knowledge on energy.
secondary teacher's professional development; teaching of energy; students' alternative ideas