Computer networks also make possible new forms of modeling activities, in which students collaboratively
construct models and simulations-and, in some cases, participate in the simulations that they construct. Greg
Kimberly developed an environment called Marketplace that enables students to participate in economic
simulations over the Internet, playing the roles of buyers and sellers in a virtual marketplace [Kimberly, 19951.
Marketplace includes online discussion facilities, designed to support not only economic deal-making among
participants but also reflection and analysis of the economic patterns that arise from the interactions. Kimberly
found that participants gained insights into core economic ideas such as supply and demand, economies of scale,
and externalities.
Our research group is currently developing a more general-purpose modeling environment for the Internet,
called the Network Clubhouse. The decentralized nature of the Internet makes it particularly well suited for
modeling and exploring the workings of decentralized systems. People encounter many decentralized systems in
their everyday lives (such as ant colonies, traffic jams, and market economies), but they generally have great
difficulty understanding the workings of such systems, often assuming centralized control where none exists
[Resnick, 19941. Research has shown that modeling activities can help people develop better intuitions about
decentralized systems. The Network Clubhouse is based on the belief that collaborative modeling activities will
provide a new avenue for people to move beyond the "centralized mindset." For example, students can use the
Network Clubhouse to collaboratively create an ocean ecosystem on the Internet, with each student
programming the behavior of an "artificial fish"-then discussing with one another the systems-level
phenomena that arise from the interactions. It is expected that students, through these activities, will be able to
develop an understanding certain scientific phenomena (such as feedback, homeostasis, and self-organization)
that are usually studied only at the university level, using advanced mathematical techniques.
With this type of activity, the Internet can support changes not only in the process of learning (bringing students
together into collaborative projects) but also in the content of what is learned (providing a natural infrastructure
for modeling and exploring decentralized phenomena). Too often, educational innovations focus only on how
students learn, without enough attention to what students learn. Many of the representations and activities used
in today's schools were developed in the context of (and are most appropriate for) pencil-and-paper technology.
New media (such as the Network Clubhouse) make possible new representations and formulations of scientific
knowledge-making that knowledge accessible to more people (and at younger ages) than previously possible.