The findings by Purdue University chemical engineers led by Associate Professor David Corti cast doubt on some aspects of a long-standing theory that attempts to describe the underlying molecular mechanism behind a phenomenon called "homogeneous nucleation."

In the conventional view, a liquid boiling and turning into a vapor takes place in a systematic process known as "nucleation and growth." The liquid first forms tiny "nuclei," or microscopic bubbles, that grow as they pick up particles. Such a conventional view is described by "classical nucleation theory," which was proposed in the 1920s.

"Our findings indicate this is not what's going on," Corti said. "The bubble grows via a mechanism very different from classical nucleation theory."

The findings by Corti and chemical engineering doctoral student Mark Uline are detailed online in the journal Physical Review Letters.