Hypermedia technology offers new opportunities for developing earth science teaching materials. During the past 3 years, the U.S. Geological Survey has conducted a series of research and development projects to assess the effectiveness of hypermedia technology in providing innovative teaching products for middle school students. The goal of this research is to develop interactive computer software that is based primarily on the visualization of earth processes to facilitate learning. As a result of the research, the U.S. Geological Survey has developed two hypermedia products that serve as prototypes of electronic teaching tools. Interdisciplinary teams were formed to design, implement, and test the educational hypermedia software products. The participation of teachers and students in the design and testing phases was critical to the success of the project. Standardized testing procedures were developed during the course of the project to ensure software quality. The combination of manual and automated testing procedures was essential to the success of product development. Preliminary results of the educational hypermedia study indicate that more stringent quantitative and qualitative evaluations of the products are needed. Producing multimedia educational tools for minimally-configured computers continues to pose problems for incorporating high-resolution animation, imagery, video sequences, and sound. The next phase of research conducted by the U.S. Geological Survey will focus on migrating from presentation-oriented hypermedia systems toward interactive applications that empower students with the capability to create their own multimedia notebooks. (Author)