In this manuscript we describe our introductory astronomy course for underg
raduate students in which students use three-dimensional (3-D) modeling too
ls to model the solar system and, in the process, develop rich understandin
gs of astronomical phenomena. Consistent with our participatory pedagogical
framework, it was our intention to establish a context that supported stud
ents in carrying out scientific inquiry using virtual models they developed
. The progression of our thinking and the course curriculum has been ground
ed in a series of "design experiments," in which we develop entire courses,
do research, and cycle what we are learning into the next iteration of the
course. In this manuscript, we use field notes, portions of case studies,
interview data, artifact analysis, and excerpts from previous manuscripts t
o situate the reader in the actual happenings of the course. Focusing prima
rily on the dynamics of the earth-moon-sun system, we illustrate the modeli
ng process and how learning evolved in this context. In general, we found t
hat 3-D modeling can be used effectively in regular undergraduate universit
y courses as a tool through which students;can develop rich understandings
of various astronomical phenomena. Additionally, we found the design experi
ment approach to be a useful strategy for supporting course design that was
both theoretically and empirically grounded. (C) 2000 John Wiley & Sons, I
nc.