OVER THE past decade, at both the university and high school levels, chemistry instructors have become keenly aware of an increasing number of students who are proving to be unable to solve complex problems. Today's students have grown up with technology, and most would prefer to do their homework using a digital tool rather than pencil and paper. Those students who do try to work out pencil-and-paper problems can become easily frustrated if they encounter difficulties and are unable to get immediate, useful feedback. To address this problem, chemistry department faculty members at Indiana University, Bloomington (IUB), developed a novel online learning tool called CALM (Computer Assisted Learning Method). CALM was initially developed for use in the general chemistry curriculum at the university, where introductory courses typically enroll between 200 and 600 students. But CALM has since made the transition to high schools, crossing one of the most formidable boundaries in U.S. education and demonstrating the potential of a P-16 system to foster highly productive cross-level cooperation. The story of CALM's beginnings is instructive. In 1996, the first author decided to introduce online homework into a large undergraduate chemistry course at IUB. The idea behind this change was simple: science involves problem solving, and to master concepts in science requires practice in solving problems and answering questions. The advantage of an online system was clear: it could provide instant feedback to the students on the correctness of their responses. Moreover, an ideal system would challenge students according to their individual strengths, so that all students would be appropriately challenged. But in the mid-1990s, online homework systems were in their infancy, and none possessed all the desired features. Consequently, it was decided to develop a system from scratch. Because developing high-quality instructional materials is both time- and resource-intensive, from the outset those of us at IUB wanted to create a system that could be broadly disseminated so that materials developed at one institution could benefit students at multiple institutions. The result of our effort is the Web-based learning tool known as CALM (http://calm.indiana.edu). Early in the development of CALM, the IUB chemistry department decided to share this learning tool, free of charge, with any high school teacher willing to be trained to use it. The training required to start using the program builds important connections between the university faculty and the high school teachers and so is in harmony with the P-16 philosophy. At the same time, high school teachers throughout Indiana have made important connections among themselves. As a result, the use of the program has dramatically increased within the state, and it has yielded some amazing outcomes. DESCRIPTION OF CALM A faculty member using CALM presents students with a set of questions to answer. These questions can be associated with review material, subject matter recently taught in the classroom, or even untaught material so as to gauge the level and abilities of the class in advance. The architecture of CALM is based on Socratic pedagogy. When a question in CALM is answered incorrectly, the architecture allows a new leading question to be posed. Thus a student can be led, step by step, through a complex problem requiring multiple steps. Since the student's responses to this unfolding series of questions can be tracked, common stumbling blocks encountered by multiple students can be brought to the attention of the teacher. Questions in CALM are generated by an algorithm, and different students in the same class will encounter different though similar questions. This algorithmic generation of individualized questions is a key feature of CALM. Not only may the question differ in numerical values, but chemical reactions or graphical images can change as well. …