This project aims to serve the national interest by bringing together a group of college faculty with a wide range of experiences and teaching needs to work together to explore and develop online resources for use in their coursework. Because many faculty both developed and made considerable use of online resources when courses were taught remotely during the COVID-19 pandemic, this is an important time for college teachers to share and build upon those experiences to make better use of web-based tools and data in teaching. Through presentations and discussions, the participants will identify and create new ways to use online resources to improve student learning in their classes. In the geosciences, some highly interactive web pages have been developed to help students understand complex topics by building on the positive effects of student-active learning. On those web pages, students are given control over graphs and other diagrams so that they can change both the data displayed, including uploading their own data, and also change features of the display itself. During the workshop, small groups of participants will design learning activities that take advantage of online interactive web pages based upon their collective knowledge and recent web experiences. The resulting activities will be made available for use by all teachers and students with access to computers. Outcomes from this workshop will be significant beyond the geosciences, serving as examples for other STEM disciplines with difficult concepts to teach. <br/><br/>Participants in the workshop will be geologists who teach courses about igneous and metamorphic rocks and/or combined mineralogy/petrology (earth materials) courses. Phase diagrams, mineral assemblage diagrams, trace element diagrams, fractional crystallization models, kinetic models, and other fundamental tools of petrology are challenging to learn. Recent developments in online resources for teaching petrology offer new paths to enhance and perhaps accelerate petrology learning. Web-based tools that bring these diagrams and models alive with mouseover, slider, and other effects have the potential to facilitate student learning of these difficult concepts and investigative approaches. A principal goal of the workshop is for petrology teachers, working together, to identify and develop new ways to use online resources to improve teaching and learning. The products of their work will be shared online with other teachers, following the good example of past petrology teaching workshops documented on the Science Education Resource Center website. The NSF IUSE: EHR Program supports research and development projects to improve the effectiveness of STEM education for all students.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.