Description

When temperature and pressure in a liquid are just right, small crystalline solids will form spontaneously. Most of these tiny solids quickly dissolve into the liquid again. However, once a crystalline nucleus has reached a critical size, it will continue to grow until all the liquid is used up.

Depicted is a crystalline nucleus of critical size from a molecular dynamics computer simulation of a simple model system called GEM-4. These particles are very soft and can even sit on top of each other. The colors correspond with different crystal structures. A Voronoi tessellation is used to identify the boundaries of the nucleus. Surrounding liquid particles are not shown. The image was rendered using the Tachyon ray tracing software.