PhET Interactive Simulations

PhET Interactive Simulations is a free collection of interactive math and science simulations created by the University of Colorado Boulder. Founded in 2002 by Nobel laureate Carl Wieman, PhET (Physics Education Technology) has grown into one of the most widely used free STEM resources in the world, with hundreds of research-based simulations spanning physics, chemistry, biology, earth science, and mathematics.

Each simulation turns an abstract concept into something students can see, touch, and experiment with. Learners can drag a mass onto a spring and watch energy transfer in real time, build a working circuit, balance chemical equations, explore the behavior of gases, or investigate natural selection - all through intuitive, game-like controls that reward curiosity and trial-and-error. Because the sims run directly in a web browser and work on tablets and Chromebooks, there is nothing to install and no account required.

For homeschooling families, PhET is especially valuable as a virtual lab. It lets students carry out experiments that would otherwise need expensive equipment or unsafe materials, making hands-on science accessible at the kitchen table. Every simulation is paired with free teacher resources - lesson plans, activity sheets, and alignment guides contributed by educators - that make it easy to build a structured lesson around a topic. The library reaches from middle school through introductory college level, so a single resource can support a student for years.

All simulations are completely free and open, translated into dozens of languages, and continually updated. Whether used to introduce a new concept, reinforce a tricky idea, or simply let a curious learner play and discover, PhET is a cornerstone free resource for any science or math curriculum.