Science museums are missing an opportunity to promote informal education, scientific literacy, public engagement and public visibility of scientists outside of museum walls via Instagram. With an analysis of 1,073 Instagram posts, we show that museums are using Instagram as a promotional broadcasting tool, with a focus on end results of collections and curation work over communication of museum-led discovery and science as a process. We suggest that science museums create more Instagram posts that offer educational information and visibility of exhibit creation and museum researchers' work behind the scenes.