Abstract
We are presenting a paper about some work carried out with future teachers of secondary schools specialized in Physics, Astronomy and Mathematics from a teacher's training college in the city of Buenos Aires, Argentina. The objective was to develop pedagogic strategies to shape a critic, scientific teacher through three different situations: work, experiments, and the situation or problematic case. We have chosen three key moments in the development of Astronomy from the historic, social, philosophical, epistemology and scientific perspectives through the following paradigmatic confrontations: The geocentric/heliocentric theory, the great debate of Shapley and Curtis, and the problem of dark matter. For each case we have worked with the didactic model of confrontation and an epistemology which accompanies the significant learning in the construction of models and theories.