This article is a methodological contribution to the use of design experiments in educational research. We will discuss the implications of a historical and situated interpretation to design experiments, the consequences this has for the analysis of the collected data and empirically based suggestions to improve the designs of the computer-based learning resources. This interpretation differs from that of the majority of other researchers who consider design experiments as fixed interventions. Our interpretation allows for an understanding of students' learning trajectories as part of the school's overall activities, which in turn has implications for suggestions regarding the improvement of computer-based learning resources. We develop argument in three different ways. First, we discuss our interpretation of design experiments and compare it with the dominant debate about design experiments as a methodological approach. Second, we discuss the implications this position has for interaction analysis methods. Finally, we empirically demonstrate this methodological implication by illustrating how vital it might be to consider data collected as part of design experiments as an element of a larger, established institutional setting characterized by inherent socio-cultural features. A conclusion that may be drawn from our situated interpretation of this design experiment is that, to improve students' knowledge constructions, it is not enough--nor is it in principle possible--to perfect the design of the technology. We also need to improve institutional aspects on how schools support students' knowledge constructions when using these technological tools, where the teacher's role in this work is invaluable. A historical and situated interpretation of design experiments provides insight into how these improvements may be made.