The short video platform TikTok, which is popular especially among young people, is increasingly used in informal educational contexts and also for science communication. In a platform-typical manner, science-related videos combine different semiotic modes such as spoken and written language, images, sound and music into complex multimodal texts. In our contribution, we analyse a selection of science-related TikTok videos by recourse to the notion of canvas and show how creators combine semiotic modes in order to stage themselves as scientists and to performatively establish a reference to science. Through an ethnographic, explorative approach, we show strategies of self-categorisation, the explicit staging of unknowingness, and references to knowledge, which in part cannot be separated from strategies for generating reach that are rather contrary to science communication. The results of our analysis reveal the potentials, but also the risks of TikTok for science communication purposes.