The Mpemba Effect: Hot Water Freezes Faster Than Cold Water

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The Mpemba effect is that, under certain circumstances and experimental parameters, it is observed that hot water freezes faster than cold water which sounds implausible since hot water, with a higher temperature than cold water, has a higher amount of internal energy which has to be lost before it starts to change its state and turn into ice. The effect got its name from Erasto Mpemba who discovered the effect that hot water freezes faster than cold water after he discovered that hot ice-cream freezes first before cold ice-cream. Philosophers and scientists throughout history, which included Aristotle, René Descarte, and Francis Bacon, in fact had already discovered this phenomenon but Erasto Mpemba further reinforced this effect. Definitions…show more content…
As such, Jeng (1998) defined it as “There exists a set of initial parameters, and a pair of temperatures, such that given two bodies of water identical in these parameters, and differing only in initial uniform temperatures, the hot one will freeze sooner.”[1]. However the term “freeze sooner” would still be unclear or ambiguous. It could mean the first to reach nucleation point or the first for all mass of the liquid water to turn into solid ice. Phenomenon There are several phenomenon which demonstrate the Mpemba Effect under several circumstances. As such, it is important to note that the Mpemba Effect only occurs under certain conditions and experimental parameters, in other words, there may be other circumstances in which the effect is not shown.[1] Instant freezing of hot water at atmospheric sub-zero…show more content…
It occurs when there is an absence of seed crystal or nucleus (nucleation points) for the formation of a crystal lattice structure by water molecules. It is found out that hot water would supercool lesser than cold water (i.e. hot water freezes at a higher temperature than cold water). Auerbach (1995) found out that that the most probable freezing temperature, Tf of hot water at 90oC was at 0oC - -2oC, with a probability of 0.41, Whereas Tf of cold water at 18oC was at -4oC to -6oC, with a probability of 0.56[3] However, the reason behind supercooling on the Mpemba Effect was not determined. In fact, theoretically, hot water should supercool less than cold water, due to the fact that hot water contains lesser amounts of dissolved gases than cold water as these gases were driven off in the process of heating the water. As such, there are less nucleation points in hot water and hence hot water would reach a lower temperature before freezing. Intermolecular forces of

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