PhET Blog

Try our new Sugar and Salt Solutions Sim to see what happens when sugar and salt are added to water. Pour in sugar, shake in salt, and evaporate water to see the effects on concentration and conductivity. Zoom in to see how different sugar and salt compounds dissolve. Zoom in again to explore the role of water.

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 bonds and lone pairs to the central atom. Check out the molecule and electron geometry names, and watch how the bond angles change dynamically as you add and remove bonds and lone pairs from your molecule. How many different shapes can you make?
Coming Soon: A Real Molecules tab, where you can compare the VSEPR model to real molecules!

Try our new Molecule Polarity sim. When is a molecule polar? Change the electronegativity of atoms in a molecule to see how it affects polarity. See how the molecule behaves in an electric field. Change the bond angle to see how shape affects polarity. See how it works for real molecules in 3D.

As part of our effort to develop sims specifically for our middle-school audience, we are adapting many of our existing sims by refining the content and controls to better align with the middle-school learning goals. We’ll release the sims (and announce them here) as we complete each one. The first that will be released in the coming months will be States of Matter: Basics. Let us know which other ones you’d like to see.

Try the new Resonance Sim for advanced undergraduate students. Observe resonance in a collection of driven, damped harmonic oscillators. Vary the driving frequency and amplitude, the damping constant, and the mass and spring constant of each resonator. Notice the long-lived transients when damping is small, and observe the phase change for resonators above and below resonance.

We’ve improved the Capacitor Lab sim with a new “Multiple Capacitors” tab, where you can explore series and parallel relationships.

Try the new Build-a-Molecule sim. Starting from atoms, see how many molecules you can build. Collect your molecules and see them in 3D! You’ll learn the differences between atoms and molecules, and how to construct them.

Are all atoms of a given element the same? How can you tell one isotope from another? Learn about isotopes, and about how to calculate the average atomic mass of an element.

Explore bending of light between two mediums with different indices of refraction. See how changing from air to water to glass changes the bending angle. Play with prisms of different shapes and make rainbows.

After more student testing, we’ve improved the Gravity and Orbits sim as well as fixed some bugs. (If you find more, please let us know!) Grab the planet and change the planet-star distance or the planet’s velocity, and explore how that impacts the orbit.