One of the challenges of science education is to integrate activities, content, and tools in a meaningful manner. One way to address this challenging goal is the transformation of authentic scientific practices into contexts for learning, in line with sociocultural activity theory. In this respect, authentic scientific practices are interpreted as the totality of human work situated in society. Within such authentic scientific practices, the activities, content, and tools are connected logically and the relevance is clear among its participants. This study presents an activity-based instructional framework that assists educational designers in transforming authentic scientific practices for the population of students in science education. The activity-based instructional framework has been dialectically constructed with the design and classroom enactment of a curriculum unit based on an authentic chemical modeling practice. The curriculum unit was developed through a participatory design process that took teachers' expertise into account. The pedagogical decisions were abstracted in design guidelines. The curriculum unit was implemented multiple times in classroom to evaluate the design guidelines. Research data were collected by means of audio-taped discussions, completed worksheets, and written questionnaires. The findings supported the potential of transforming authentic scientific practices to achieve meaningful science education.