51�Թ�

To get that 3D view, they use a combination of the photoelasticity to illuminate the force chains, along with a method called computed tomography, similar to that used in medical CT scans, to reconstruct a full 3D image from a series of 2,400 flat images taken as the object rotates through 360 degrees.

Using a technique called integrated photoelasticity, they immerse the drop in a liquid and shine polarized light through it.