1 Teacher Enactment of Web GIS Tectonics Investigations Alec M. Bodzin, Denise M. Bressler, and Farah Vallera, Lehigh University Paper presented at 2013 NARST Annual International Conference April 6-9, 2013 in Rio Grande, Puerto Rico. Abstract A potential method for teaching geospatial thinking and reasoning is through spatially-enabled learning technologies. We developed four Web GIS (Geographic Information Systems) tectonics investigations using an instructional model with eight key elements for teaching science with spatially-enabled learning technologies such as GIS. This study investigated the variations of implementation fidelity when four urban middle school teachers enacted the Web GIS tectonics investigations. Twenty-nine observations were conducted in the classrooms of the four teachers with an observational protocol. Pedagogical implementation was mostly consistent for each teacher for each ability track level they taught. There was little variability among the teachers with regards to adherence to the key elements of the instructional model during the curriculum enactment. The teachers did not modify the instructional materials and predominantly enacted the investigations as designed. Curriculum time constraint played a large role when the last key element of the model was not implemented. The findings provide support that geospatial thinking and reasoning related to a science content area can be taught formally to students in an urban middle school and can be supported by appropriately designed curriculum materials and Web GIS. Geospatial thinking, a subset of spatial thinking, is a skill that necessitates knowledge about space, the ability to use tools of representation properly, and reasoning skills (National Research Council [NRC], 2006). Geospatial reasoning skills provide a means for manipulating, interpreting, and explaining structured information and are involved in higher-order cognitive processes that include solving problems and making decisions. One potential method for teaching geospatial thinking and reasoning is through spatially-enabled learning technologies, such as Geographic Information Systems (GIS) (Battersby, Golledge, & Marsh, 2006). GIS may enhance science curriculum learning by adding an emphasis on geographic space, visualization, scale, representation, and spatial thinking and reasoning skills. While these technologies show promise to support the development of geospatial thinking and reasoning, the NRC (2006) report Learning to Think Spatially: GIS as a Support System in the K-12 curriculum, pointed out that