The “spring model” belongs to the class of single bubble models in the sense that it is based on the concept of a vapor bubble bounded by an upper and a lower plane interface across which mass, energy, and momentum are transferred. It is characterized by the hypothesis that the bubble transformations occur under adiabatic conditions. From the numerical point of view, it is very simple and requires a very short computing time. The model and its name were suggested by the analysis of the damped oscillations of the pressure observed during one of the single-pin boiling tests performed on the ENA-2 loop. Pressure, temperatures, and void fractions calculated by the spring model were compared with the experimental ones and very good agreement was observed in this case.