The Physics and Chemistry Education Technology (PhET) Project is developing an extensive suite of online, highly-interactive simulations, with supporting materials and activities for improving both the teaching and learning of physics and chemistry. There are currently over 70 simulations and over 250 associated activities available for use from the PhET website (http://phet.colorado.edu). These web-based resources are impacting large number of students. Per year, there are currently over 4 million PhET simulations run online and thousands of full website downloads for offline use of the simulations. The goal is that this widespread use of PhET's research-based tools and resources will improve the education of students in physics and chemistry at colleges and high schools throughout the U.S. and around the world. This PhET project combines a unique set of features. First, the simulation designs and goals are based on educational research. Second, using a team of professional programmers, disciplinary experts, and education research specialists enables the development of simulations involving technically-sophisticated software, graphics, and interfaces that are highly effective. Third, the simulations embody the predictive visual models of expert scientists, allowing many interesting advanced concepts to become widely accessible and revealing their relevance to the real world. And finally, the project is actively involved in research to better understand how the design and use of simulations impacts their effectiveness - e.g. investigating questions such as "How can these new technologies promote student understanding of complex scientific phenomena?" and "What factors inhibit or enhance their use and effectiveness?".
