Central concepts in the teaching of thermal science, such as heat and temperature, are abstract in the sense that we cannot directly see how they are manifested in nature. In learning about thermal phenomena, we rely largely on our sense of touch to assess the perceived hotness or coldness of objects, and tend to believe – misleadingly – that our sense of touch is a dependable thermometer. Accordingly, science education research has found thermal concepts to be challenging for students to grasp. In taking on this conceptual challenge, we have initiated a research programme, in which we explore how hand-held infrared (IR) cameras can support students’ understanding of thermal phenomena, by making the invisible visible. We have developed laboratory exercises involving IR cameras for different levels of physics education, based on a predict, observe and explain (POE) approach. In a pilot study, 7th graders were invited to experience the sensation that metal feels colder than wood at room temperature, and see heat convection through a sheet-metal knife when they held it for two minutes. In a subsequent study, as part of a storyline, two classes of 4th graders were introduced to a heat-flow model and interacted with four laboratory stations, relating to heat and thermal insulation. Furthermore, in a study that broadened the scope to mechanics at the upper secondary level, students were asked to explain the increased temperature due to friction between an eraser and a table, or as a large metal ball fell onto asphalt. In all contexts to date, IR cameras – basically interactive thermal looking glasses – have been found to be an engaging, easy-to use technology. In particular, they invite ‘instant inquiry’ of thermal phenomena, and stimulate the adoption of a macroscopic heat-flow model. Further development of IR-camera supported laboratory exercises for university teaching is under way.