To support preschool children’s learning about data in an applied way that allows children to leverage their existing mathematical knowledge (i.e. counting, sorting, classifying, comparing) and apply it to answering authentic, developmentally appropriate research questions with data. To accomplish this ultimate goal, a design-based research approach was used to develop and test a classroom-based preschool intervention that includes hands-on, play-based investigations with a digital app that supports and scaffolds the investigation process for teachers and children.