Science museums are key locations for informal education. They also enable research that explores how families structure their activities and conversations and how these contribute to learning experiences. The aim of this exploratory study, using qualitative and quantitative methodologies, was to analyse the process of family interactions during visits to a Brazilian science museum focused on microbiology and how their conversations mediated their learning experiences. Four groups, each consisting of a single family with children, participated in the study. Their visits were recorded using a subjective camera, and the audiovisual data were analysed regarding types of interactions and conversational content, based on an analysis protocol. The results reveal that the interactions and social dynamics that family groups engaged in during their visit provided cognitive and social learning experiences. The study also offers evidence on the role of children, the importance of conversations with adults during the visits, and the relevance of objects on exhibition in promoting learning conversations.