GIS has shown promise in Project Based Learning (PBL) environments, but many obstacles exist in its integration into school curriculums. This article discusses the development and utilization of an online GIS tool that was created to illustrate that the perceptual gap between relevance and ease of use of GIS software can be bridged at the K-12 level. This online GIS tool, referred to as the H2OMapper, is a watershed data management system designed to directly support teachers and students in middle school earth science. It features a student observation database, preprocessed contextual datasets, and an easy-to-use interface to reduce the time it takes to learn operations. Teacher experimentation with the software indicates that negative perceptions about GIS technology can be reversed if the adoption process is carefully planned. (Contains 6 figures and 1 note.)