Research and undergraduate training in the earth sciences are strongly field-based, but the field environment is rarely used for non-majors or for teacher education. Research into the design and effectiveness of earth science field trips suggest that field experience enhances the learning of fundamental geological concepts, but only if field trip design minimizes unfamiliarity with surroundings and is process and investigation oriented. This project tests protocols and techniques for using the outdoor field environment to increase elementary school teachers' content knowledge and confidence in field-based, inquiry-based teaching. Specifically, the research is aimed at quantifying the impact of carefully designed field learning on teachers' understanding of sedimentary systems and environmental change through time as recorded in sedimentary rocks. Measurements were made of prior knowledge, understanding gained after a preparatory classroom session, and final resulting content knowledge after a subsequent one-day directed inquiry field experience at Torrey Pines State Reserve. Changes in attitudes toward science and Earth science were also tracked through this process. We have also conducted a short case study investigation involving four individual teachers from the San Diego City Schools who participated in this program to assess resulting changes in their classroom teaching approach. The data suggests that content knowledge of sedimentary structures, depositional environments, and geologic time were enhanced in the field. The data also indicates that the teachers' confidence to use the field environment to teach inquiry-based science was increased following the field experience. This study suggests that in-service teachers, as well as pre-service teachers and other non-geology majors are likely to benefit in terms of increased content knowledge and conceptual understanding from the incorporation of directed-inquiry field experiences in geoscience courses.