Abstract
While constructivism has made its mark concerning learning in science classrooms, little has surfaced so far relating to the education and professional development of science teachers. This paper not only deals with the implementation and evaluation of such a constructivist course, but extends the argument towards the induction of teachers into ‘critical constructivism’ through their own action research projects. Data are drawn from a single case study which illuminates the induction process and illustrates the changes taking place in the professional life and the reflective practice of one teacher as she deals with biological concepts with a class of 13‐15 year olds. The Brazilian setting for the course lends resonance to its international significance.