This study presents the implementation of narratives in a school chemistry laboratory; the narratives were directed to improving the learning about oxidation-reduction reactions among secondary students. The aims of the study are to characterize students' written narratives based on their lab-work and to categorize different 'types' of narratives related to how they approach scientific knowledge. We identify the application of 'cognitive-linguistic skills'. Students conducted a series of school science experiments (on oxidation-reduction) following a set protocol provided by the teacher. Once the lab activity was completed, they were asked to write a text ('experimental narrative') on it; the narrative became part of their laboratory report. Analysis of the narratives shows that a high percentage of students approach the written reconstruction of the experiment in a descriptive way. According to the categories applied in this study, the use of experimental narratives favors 'reflective' scientific learning.