PhET is a suite of research-based interactive computer simulations for teaching and learning physics, chemistry, math, and other sciences. PhET simulations can be run online or downloaded for free from the PhET website. The simulations are animated, interactive, and game-like environments where students learn through exploration. They emphasize the connections between real-life phenomena and the underlying science, and help make the visual and conceptual models of expert scientists accessible to students. PhET simulations are primarily developed for and tested with university and high school students, but have been found to be educational and fun for students "from grade school to grad school."