To study the interactions between electrons in a material, physicists have come up with a number of tricks over the years.

This is largely a show-and-tell demo. You select which models you want to highlight. Students may find it useful to be able to handle the models personally, which is great for a small class. If you ...

The crystal lattice parameter is 0.563 nm. The diagram shows both a unit cell with ion locations indicated (a) and a space filling model (b) of ionic hard spheres. The cohesive energy of NaCl is - ...

it determines the size and shape of the lattice “box” and which atoms will go into it. Then, it predicts the arrangement of atoms within the box. For each diffraction pattern, the model ...