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

‪Natural Selection‬

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 …

‪States of Matter‬

Explore how organisms with different traits survive various selection agents within the environment.

Explore natural selection through interactive simulations, observing how traits influence survival in changing environments.

‪Energy Skate Park: Basics‬ 1.1.36

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!

Explore density through interactive simulations, modifying mass and volume of blocks to discover conditions for sinking or floating in water.

‪Energy Skate Park‬