Descriptions of disciplinary practices can suggest visions of authentic classroom activities. Designing activities that are effective, however, requires an additional framework for identifying a discipline's generative resources -- that is, those learning targets that enable students to make disciplinary sense and progress in subsequent situations. This study represents an empirical exploration of the generative resources supported by alternative descriptions of experimentation, 1 focusing on its logical aspects and another on its measurement aspects. Each description of experimentation was portrayed in 1 of 2 concurrent 6th-grade units. In a broad capture of learning outcomes, assessment data suggest particular dimensions of learning -- characterized here as game, pieces, and players -- account for students' subsequent generative behavior. Striking differences in disciplinary facility were apparent from what students learned from these contrasting units, highlighting the instructional importance of supporting generative resources for valued disciplinary activity. This exploration of generative resources draws on recent efforts to reconceptualize transfer and adds to accumulating examples of design-based research as an effective methodology for supporting sound instruction and innovation.