This paper addresses how students explore, construct, validate and use statistical models when facing situations designed from a socio-critical perspective. The case study used is a statistics lesson designed by a statistics teacher and a researcher. The lesson centers on nutritional information and was implemented in a 7th-grade classroom at a public school in a Northwest Colombian city. In small groups, students gathered their own data, and subsequently organized and analyzed the data, and presented their findings to the class. The main sources of data were students' discourse in the classroom, students' artifacts and the researcher's journal. The findings describe a route in which students explore, construct, use, and validate their models. The results elaborate the technological and the reflective knowledge that took place in the model building activity.