This project launches the creation of a new class of playground apparatus based on an emerging understanding of how students learn mathematics and science concepts. The equipment will be highly interactive and instrumented, providing opportunities for thoughtful, planned actions that children can evaluate with the aid of instrumentation. The design principles used are applicable to many mathematics and science topics, but this initial demonstration is restricted to creating units which embody some important concepts from classical mechanics. We will create, test, evaluate, and begin the dissemination of units incorporating timing, motion, and force sensor electronics designed to give children real- time, symbolic feedback to reflect their experiences. The first nine months will be devoted to the apparatus design, building, testing, safety evaluation, and formative research. We will install apparatus in three highly varied sites to evaluate the design. In a second phase, improved units will be built for one site and detailed research on student learning undertaken. If we observe the hypothesized learning, the approach we use in mechanics will have broad generalizability. This work could lead to interesting and highly educational apparatus addressing other science fields and useful in a broad range of informal learning environments.