This research studies the critical thinking skills of six teenagers in their final years of high school. It looks at the way those students use a set of cognitive skills in order to analyze scientific and pseudoscientific information available in online news articles. Semi-structured interviews were conducted with six students chosen according to their results in a questionnaire about interest in science topics. Results show a large gap between participants' use of critical thinking skills. Most of these skills were mainly used for text comprehension, evoking general knowledge, numeracy, arguments assessment and production, and life skills (open-mindedness and metacognition). The participants were often confused when they were asked to justify their stances, and when they had to compare arguments' value. This exploratory study could lead to a better understanding of teenagers' strengths and weaknesses in news media literacy, and the part that schools could play in helping students develop them.