When hot water freezes before cold

  title={When hot water freezes before cold},
  author={J. I. Katz},
  journal={American Journal of Physics},
  • J. Katz
  • Published 27 April 2006
  • Physics, Materials Science
  • American Journal of Physics
I suggest that the origin of the Mpemba effect (the freezing of hot water before cold) is due to freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. The solutes are concentrated ahead of the freezing front by zone refining in water that has not been heated, reducing the temperature of the freezing front, and thereby reducing the temperature gradient and heat flux, slowing the… 

Figures from this paper

When does hot water freeze faster then cold water? A search for the Mpemba effect
It is possible to consistently observe hot water freezing faster than cold water under certain conditions. All conditions except the initial temperature of water specimens must be the same and remain
On the Paradox of Chilling Water: Crossover Temperature in the Mpemba Effect
Unlike most of the research on the Mpemba effect which has focused on verifying the observation that warm water freezes faster than cold water, our work quantitatively investigates the rates at which
A search for the Mpemba effect: When hot water freezes faster then cold water
An explanation for why hot water will sometime freeze more rapidly than cold water is offered. Two specimens of water from the same source will often have different spontaneous freezing temperatures;
When the Hotter Cools More Quickly: Mpemba Effect in Granular Fluids.
It is shown that the Mpemba effect is present in granular fluids, both in uniformly heated and in freely cooling systems, and in both cases the system remains homogeneous, and no phase transition is present.
Explanation for the Mpemba Effect
Water molecules are oriented dipoles joined by hydrogen bonds. When water is heated, this structure collapses (i.e., the entropy increases). When water is re-cooled to a lower temperature, the
Reply to Burridge & Linden: Hot water may freeze sooner than cold
In a recent paper in Scientific Reports, Burridge \& Linden misinterpret the Mpemba effect as a statement about the rate of cooling of liquid water, when it is in fact a statement about the rate of
Axisymmetric natural convection-driven evaporation of hot water and the Mpemba effect
Abstract The Mpemba effect is popularly summarized by the statement that “hot water can freeze faster than cold”, and has been observed experimentally since the time of Aristotle; however, there
Questioning the Mpemba effect: hot water does not cool more quickly than cold
It is concluded that there is no evidence to support meaningful observations of the Mpemba effect, and at first thought one might consider the effect to breach fundamental thermodynamic laws, but this is not the case.
Can natural convection alone explain the Mpemba effect
Abstract The Mpemba effect is popularly summarized by the statement that “hot water can freeze faster than cold water”, and has been observed experimentally since the time of Aristotle; however,
Revisiting the Mysterious Mpemba Effect
The effect of hot water freezing faster than cold water is mentioned in Greek literature. However, it came out as a scientific phenomenon during the last few decades and is known as Mpemba effect


Supercooling and the Mpemba effect: When hot water freezes quicker than cold
Temperature measurements taken near vessel walls show that initially hot water may well begin to freeze quicker than cold. This is not, as previously surmised, due to the cooling history of the water
Evidence of a convective instability allowing warm water to freeze in less time than cold water
This experimental study explores the possibility that warm water may freeze in less time than cold water due to natural convection alone, i.e., in the absence of significant cooling by evaporation.
Freezing of aqueous solutions containing gases
The Mpemba effect and possible relation to the gases dissolved in water is investigated. The time of cooling and freezing of water and the enthalpy of its freezing in relation to the start
The Mpemba effect: When can hot water freeze faster than cold?
We review the Mpemba effect, where initially hot water freezes faster than initially cold water. Although the effect might appear impossible, it has been observed in numerous experiments and was
The Distribution of Solute in Crystals Grown from the Melt. Part I. Theoretical
The incorporation of solute elements into single crystals of germanium grown from the melt is examined in terms of a simple model. The theory takes account of the contribution of solute transport in
Dynamic solidification of a binary melt
The fundamental physics and fluid dynamics of a solidifying two-component system cooled from below is analysed quantitatively. Theoretical results for the rate of growth of the solid are in good
The Freezing of Hot and Cold Water
  • G. Kell
  • Materials Science, Physics
  • 1969