Based on a traditional image of science, we restrict the role of experiment in schools to the confirmation of the informational theories accumulated in textbooks. As the theoretical statements are only validated in laboratories, we present to students a finished science and, consequently, not thinking people. From our interpretation of light refraction and the photoelectric effect from the perspective of Newton and Einstein respectively, we present a set of experimental workshops implemented in the Educational Institution School Normal Superior of Medellin and the Educational Institution Francisco Miranda, there, the experiment is involved in the construction of physical knowledge and not only in its justification. Workshops show that the experiment participates both in the concertation, among a group of students, of explanations of optical phenomena as in their elaboration. This research reveals that the students analyze and reach consensus with their interventions in the experiments. So, we can give a broader meaning to the role of experiment and theory in the physics class, considering students as active liables in the elaboration of knowledge, and to involve in it the discussion mediated by argumentation from the interpretation that each student made of the phenomena.