Project Summary The primary goal of this research project is to investigate the nature of the development of models by students in technology enhanced environments in middle school and secondary school settings. Model building occurs as students use and create symbolic, graphical, numeric, geometric and verbal descriptions of meaningful situations and structurally similar situations. Understanding the way learners develop and make sense of generalizable models and their underlying structure is the crucial focus of this research. This research project should lead to a more refined conceptualization of the model building cycles that learners engage in and to a characterization of those activities and strategies that support multiple stages of successful model building. This work in grounded in socioconstructivist learning theory and will significantly extend the extensive base of problem solving research in mathematics education by investigating multiple cycles of modeling. The results of this research should have significant implications for the design of tools and simulations as generalizable and re-usable technologies. Integrated with this research is an education plan to develop an undergraduate course that will provide pre-service mathematics teachers with the modeling experiences they need as learners of mathematics in order to teach from a modeling perspective. In addition, the proposed research should lead to the development and refinement of principles for the design of sequences of model building activities and studies of the associated pedagogical strategies and methods of assessing student learning in a technology enhanced modeling environment. These principles and studies will lead in turn to the development of guidelines and materials for teacher professional development. Careful examination of the models that students build will provide powerful new means of assessing student learning and insight into the effective use of technological tools. An Advisory Committee will be form ed to provide guidance and advice throughout the project.