Explore atomic structure and isotopes by building atoms with protons, neutrons, and electrons in this interactive simulation.

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!

How did scientists figure out the structure of atoms without looking at them? Try out different models by shooting light at the atom. Check how the prediction of the model matches the …

Explore molecule shapes by building molecules in 3D! How does molecule shape change with different numbers of bonds and electron pairs? Find out by adding single, double or triple …

Build an atom using protons, neutrons, and electrons, and observe changes in element, charge, and mass with this interactive simulation.

‪Build a Molecule‬

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 …

Explore nuclear fission and control energy production in this interactive simulation.

Create atoms with protons, neutrons, and electrons using this interactive simulation to explore changes in element, charge, and mass.

Build a nucleus from protons and neutrons, explore stability and radioactivity with this interactive simulation.