Free science and math simulations for teaching STEM topics, including physics, chemistry, biology, and math, from University of Colorado Boulder

Build an atom out of protons, neutrons, and electrons, and see how the element, charge, and mass change. Then play a game to test your ideas!

By converting our sims to HTML5, we make them seamlessly available across platforms and devices. Whether you have laptops, iPads, chromebooks, or BYOD, your favorite PhET sims are always right at your fingertips.Become part of our mission today, and transform the learning experiences of students everywhere!

Explore the states of matter with interactive simulations that show how molecules form solids, liquids, and gases.

Build and test circuits with batteries, resistors, light bulbs, and switches. Learn about series and parallel circuits, Ohm's law, and conductors and insulators.

Experiment with an electronics kit! Build circuits with batteries, resistors, ideal and non-Ohmic light bulbs, fuses, and switches. Determine if everyday objects are conductors or insulators, and take measurements with an ammeter and voltmeter. View the circuit as a schematic diagram, or switch to a lifelike view.

Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations. PhET sims are based on extensive education <a {{0}}>research</a> and engage students through an intuitive, game-like environment where students learn through exploration and discovery.

Explore gravity and orbits with interactive simulations.

Explore the solar system with interactive simulations and learn about the movement of planetary objects.

Explore the basics of states of matter and how they change with temperature and pressure in this interactive simulation.