This article deals with a case study about how a teacher uses previous knowledge of students to approach a new concept. To this end, sciences classes were filmed during the execution of a didactic sequence, in order to investigate how previous knowledge of the students was treated in the classroom along the approach of the theme. From these results, we saw how the teacher dealt with previous knowledge of their students. We identified that there were occasions when she considered them and others in which she disregarded them. Although they are antagonistic actions, both the facts, to consider or to dismiss, have in common the search for keeping the focus on the concepts, defined by the teacher as those that should be the object of attention for the students.
Previous knowledge; Teaching sciences; Strategies to teaching
