A low-frequency ultrasonic device(50-100 kHz) in highly sharpened end sensors that behave as point sources was applied to explore the relations between the physical properties measured through the variation of the wave time-of-flight (transit time of wave) and structural changes during gel formation. This is related to two factors: the ambient temperature and the: mechanical resistance of the medium. The network evolution was interpreted by an approach based on the Flory model. The physical significance of this model was shown through a series of experiments using a low-frequency ultrasonic technique. Response curves demonstrate the different stages during gel formation.