Mpemba effect

"[citation needed] Francis Bacon noted that "slightly tepid water freezes more easily than that which is utterly cold.

After the lecture, Mpemba asked him, "If you take two similar containers with equal volumes of water, one at 35 °C (95 °F) and the other at 100 °C (212 °F), and put them into a freezer, the one that started at 100 °C (212 °F) freezes first.

[11] In 2016, Burridge and Linden defined the criterion as the time to reach 0 °C (32 °F; 273 K), carried out experiments, and reviewed published work to date.

[12] Experimental results confirming the Mpemba effect have been criticized for being flawed, not accounting for dissolved solids and gasses, and other confounding factors.

[13] Philip Ball, a reviewer for Physics World wrote: "Even if the Mpemba effect is real — if hot water can sometimes freeze more quickly than cold — it is not clear whether the explanation would be trivial or illuminating.

"[4] Ball wrote that investigations of the phenomenon need to control a large number of initial parameters (including type and initial temperature of the water, dissolved gas and other impurities, and size, shape and material of the container, and temperature of the refrigerator) and need to settle on a particular method of establishing the time of freezing, all of which might affect the presence or absence of the Mpemba effect.

Zhiyue Lu and Oren Raz yielded a general criterion based on Markovian statistical mechanics, predicting the appearance of the inverse Mpemba effect in the Ising model and diffusion dynamics.

[15] Antonio Lasanta and co-authors also predicted the direct and inverse Mpemba effects for a granular gas in a far-from-equilibrium initial state.

[18][19] In 2017, Yunwen Tao and co-authors suggested that the vast diversity and peculiar occurrence of different hydrogen bonds could contribute to the effect.

"[28]In addition to their theoretical work, which used non-equilibrium quantum dynamics, their paper includes computational studies of spin systems which exhibit the effect.

[29] They concluded that certain initial conditions of a quantum-dynamical system can lead to a simultaneous increase in the thermalization rate and the free energy.

Temperature vs time plots, showing the Mpemba Effect.