The aim of this work is, based on the epistemology of Gaston Bachelard, to understand aspects of the construction of the concept of time by elementary and high school students. The main study consisted of 17 (seventeen) semi-structured interviews. The data analysis allowed outlining the most distinctive characteristics of the conceptualisation of time, a process that could be represented as a movement towards an increasing objectivity and rationalism. It was also possible to evaluate the relevance of our theoretical framework for the interpretation of this process. Particularly, the theoretical notions of epistemological obstacle and epistemological profile were fruitful when confronted against the empirical data.