Singularities in macroscopic systems at discontinuous phase transitions are replaced in finite systems by sharp but continuous changes. Both the energy differences between metastable and stable phases and the energy barriers separating these phases d
ecrease with decreasing particle number. Then, for small enough systems, random heterophasic oscillations of the entire system become an observable form of thermal motion. Under certain conditions, these oscillations take the form of oscillatory nucleation. We discuss mechanisms and observation conditions for these random transitions between phases.
