iPad Screenshots


Atoms and ions are brought to life in "Salts" -- a fully interactive atomistic simulation that reveals the motions of atoms and ions as they interact to form beautiful crystals. Discover the physics behind the structures and properties of these minerals, and explore the effects of charge and ionic radii on melting points, bond strength, and crystal lattices.

Fun for all ages! In this App you can interact with a sophisticated computational chemistry simulation right on your iPad. This 2-D Molecular Dynamics simulation computes the motions of atoms and ions as they attract or repel, and collide with one another. Modeled after the user interactions from "Atoms in Motion": with the tap of a finger you can add, delete, and move atoms, pinch or expand to dynamically change the volume, and with a gentle swipe of your finger the temperature can be scaled between 1 - 1,500K. Now as you build and create experiments, you can easily save, manage, and organize them from within the App.

Learn about Coulomb's law, the states-of-matter, and the behaviors of ionic solids, liquids, and gases! This Molecular Dynamics simulation solves the pairwise Coulombic interactions between ions and includes a strong repulsive shell to define their radius. "Salts" includes the following ions: Na+, Cl-, Ca2+, and S2-; and a neutral gas atom: He. In the simulation you can readily make NaCl (Sodium Chloride) and CaS (Calcium Sulfide) crystals -- both of which have the rock salt structure. Alternatively, you can create more complex salts such as CaCl2 (Calcium Chloride) and Na2S (Sodium Sulfide) to explore the effects of balancing charges within the crystals. Finally, the simulation includes helium (He), which is a neutral noble gas element that interacts through van der Waals forces.

Enjoy the atoms (and the ions)!

What’s New

Version 3.0

Updated for iOS 11

Ratings and Reviews

5.0 out of 5
11 Ratings
11 Ratings
Safecracker’s Aficionado ,

Salts: A Sweet App!

The two molecular dynamics simulations from Atoms in Motion are absolutely amazing! Congratulations to the developers for tackling ionic solids – ‘Salts’ is a very useful simulation! It is wonderful to be able to use this in the classroom, and demonstrate atomic motion in real time right from the iPad. Also, a big thank you for the ability to save and name states; I now have over a dozen states that I can effortlessly call up during class. The interactivity, stability, and computational speed are impressive, and the interface is intuitive. While I miss the ability to ‘throw atoms’ and play molecular billiards, I thoroughly appreciate the ability to drag and place atoms within crystals. With patience, I have also managed to build some impressively large crystals of my own.

The rock salt crystals are very easy to visualize in 2d, but it would be even better if this simulation could be run in 3d. The inclusion of helium within the simulation makes for some excellent additional teaching points, and the broad temperature range of 1-1,500K allows me to cover a wide range of concepts within one App. All in all, the sweetest app out there - thanks again for the great simulations!

Arrrmondo! ,

Good Stuff

Salts ups the game with ionic potentials! Net charge effects, crystallizations, it's all there. Quite a step up in complexity from AIM, the previous app from the developer.

The best chemistry app out there for truly visualizing the interactions at a very fine and macro level. So good.

Wykeham ,

Great for chemistry

I have loved using this app to teach temperature, phase changes, and lattice energy concepts to my chemistry classes. I hope the company develops an app to show ions and molecules in aqueous solution, and another for chemical equilibrium. Seeing the atoms and ions in motion is so helpful.


Atoms In Motion LLC
11.3 MB

Requires iOS 9.0 or later. Compatible with iPad.



Age Rating
Rated 4+
© 2017 Atoms In Motion LLC


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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