Fig. 3.

Schematic of the mechanism of evaporation showing how the vapor-like portions develop as the system transitions from a confined liquid to vapor. The yellow portions delineate the instantaneous liquid/vapor interface (51) and the water molecules are removed for visual clarity. The mechanism proceeds in three steps: 1, surface bubbles form; 2, surface bubbles grow/coalesce to form a gap-spanning subcritical vapor tube; and 3, the vapor tube expands and crosses the nucleation barrier. Note that all bubbles shown abut one of the walls.