A growing body of work focuses on physicalisations based on personal, everyday data. Despite growing interest, little is known about how to educate people on their creation. We designed a teaching method of 'Data Diaries', which consists of five representation assignments that move from visualising to physicalising personal data. The Data Diaries were used in a semester project, with the aim of creating an interactive physicalisation. We analysed the Data Diaries, written reports, and participant interviews. Our analysis shows that people need to overcome the challenge of using materiality to communicate data, which happens in four stages. Moreover, the materiality made participants realise that physicalisations do not focus on efficiency and accuracy, but on the story of the data, by referring to its origin, use of personal mappings, and reduction. As physicalisations blur the line between quantitative and qualitative, designing them engenders a change in our notion of 'data'.
CCS CONCEPTS• Human-centered computing → Empirical studies in HCI; HCI theory, concepts and models.