We've received funding for a new project that will explore how middle school students think and learn about computational data visualizations. The DataSketch project will develop educational toolkits and materials for students in the middle grades to develop flexible competence reading and creating interactive data visualizations. The project includes the development and study of a tablet based toolkit for students to sketch and program visualizations that respond to archival or live data stream input. We'll use this environment and our work with partner classrooms to uncover what grade 5-8 students already know about data visualization. We'll also see how we can help young people come to understand data visualization as a tool for exploring and discovering new things about their world.