This K-8 curriculum has developed spatial-temporal reasoning skills with the framework of already established Earth Sciences content standards. The instructional methods used include applications of geographic information systems (GIS), which constitutes a powerful medium advancing spatial and temporal literacy of students, and satisfies the standards-based reform movements emphasis on inquiry-based constructivists learning, critical thinking skills, group learning, and the interdisciplinary nature of science. This new curricula is being developed and implemented within the framework of an interactive association between the San Diego State University pre-service teacher training program, and K-8 students and in-service teachers from local school districts. The strong formative assessment allows for iterative development of new curricula. K-8 pre-service teachers from the SDSU Liberal Studies program are recruited and trained to present the new curriculum materials serving the dual purpose of providing "on-the-job-training" for pre-service teachers, while learning Earth Science content. San Diego State University has a strong infrastructure to support curriculum development because the elementary and middle schools in the San Diego metropolitan area include students from diverse ethnic and socioeconomic backgrounds. Results of this project are being disseminated via the Web, CD-ROMs, professional meetings and publications.