This research analyses what happens when a critical reading activity based on a press article dealing with an energy-related problem is implemented with two groups of students of 13-14 years old and 16-17 years old in the same school (a total of 117 students). Specifically, the research analyses the students' profiles from the standpoint of their attitudes to the information given in the news story and the use they make of it when writing an argumentative text. It also analyses the difficulties the students have when it comes to applying their knowledge about energy in a real-life context. Lastly, some strategies are suggested for helping students to critically analyse the scientific content of a newspaper article. Three reader profiles were identified (the credulous reader, the ideological reader and the critical reader). No significant differences were found in reading profiles in terms of age or scientific knowledge. The findings show that the activity helped to link science learning in school with facts relating to an actual context, particularly in the case of students with more science knowledge.