DYNAMICS OF THE MPEMBA EFFECT: Collisions, Convection, and Kinetic Inertia

The Mpemba Effect —the apparent paradox that hot water can freeze before cold water— is explained through three elementary physical principles: Greater molecular agitation: The particles of hot water move with greater speed and amplitude, increasing the frequency and intensity of collisions with the cooling medium. Induced convection: The accelerated energy transfer generates thermal gradients that trigger convection, constantly renewing the heat exchange surface. Kinetic inertia and active nucleation: Upon reaching the same temperature, hot water retains a velocity distribution with more energetic particles, which act as a molecular "hammering" that locally disrupts the liquid structure and facilitates the formation of the first ice nuclei. The model is universal, requires no exotic mechanisms, and explains both the inconsistent replicability of the phenomenon and its dependence on initial conditions.Note: This publication has been supplemented by a more complete version available here: https://doi.org/10.5281/zenodo.22133494