This paper presents a study conducted in a private school in Recife - PE, Brazil, with 25 students from 1st year of high school. One of the focuses was to evaluate the implementation of the strategy FlexQuest on the teaching of radioactivity. The FlexQuest incorporates, within the WebQuest, the Cognitive Flexibility Theory (TFC), which is a theory of teaching, learning and knowledge representation, aiming to propose strategies for the acquisition of advanced levels of knowledge. With a qualitative approach, there were interventions of application having, as axle, an analysis of landscape crossings that the students have accomplished during the execution of required tasks. The results revealed that this strategy involves audiovisual resources, and these make learning possible, provided that strategies are embedded in a constructivist approach to teaching and learning. In this sense, it was perceived to be effective, the introductory level/stimulator, for the understanding of the applications of radioactivity. Showing a tool based on real situations, enabling students to develop the critical eye on what it is televised, including also the study of radioactivity.