Research in science education has extensively defended the use of analogies as an effective instructional tool in facilitating students’ learning of science. The power of teaching science on the basis of analogies lies in that it allows students to form cognitive links between what they are learning and what they already know, harmoniously integrating, in this way, the new concepts with their existing ones. Whilst such prior research has added instructional value to the use of analogies in facilitating new concepts learning, what has not yet been studied directly is students’ self-generation of analogies and whether there is any connection between these analogies generated and misconceptions students may hold and are found to be persistent and widespread from early childhood to late adulthood. We report in this paper on a cross-age study in which students from five different age groups were asked to make predictions across a range of novel situations and explain the reasons that led them to these predictions. Having reported elsewhere on the regular use of analogies students drew upon in order to make their predictions, we focus here on the analogies students self-generated per se and their connections to popular misconceptions. According to the findings, students’ self-generated analogies revealed not only the misconceptions they hold but also their origins. We suggest, therefore, that the use of analogies should be extended beyond the aim of facilitating the learning of new and unfamiliar concepts by comparing them with a concept or situation students are familiar with. We argue that they can serve as a diagnostic form of assessment revealing both the misconceptions students might hold as well as the prior knowledge upon which these are founded.