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The effect is named for its rediscoverer, the Tanzanian high-school student Erasto B. Mpemba , in 1963 after observing the freezing of ice cream in cookery classes; he published experimental results with Dr. Denis G. Osborne in 1969. At first sight, the effect is contrary to Newton's law of cooling. However, it has been widely reproduced though it is still poorly understood. The effect is not universal under all experimental conditions, so its exact requirements have proved difficult to specify.

It is believed that the effect arises from some interaction between:

• Evaporation reducing the volume to be frozen
• Effect of boiling on dissolved gases and ions (lime scale formation). The more dissolved material the lower the freezing point and more time required to freeze.
• Convection
• Effects from surroundings such as the insulatingThis page refers to thermal insulation. For electrical insulation see insulators, and for sound insulation see sound proofing. Often the same techniques used for thermal insulation can be used for sound insulation as well. Insulation is sometimes confused effects of frostThis article is about the weather phenomenon. Frost is also the name of a place (see Frost, Minnesota), a Freenet client (see Frost), an Australian band (see Frost (band)), a video game character and a common surname i. Doug Frost or Robert Frost. Frost l
• SupercoolingSupercooling is the process of chilling a liquid below its freezing point, without its becoming solid. A liquid below its melting point will crystallize in the presence of a seed crystal or nucleus around which a crystal structure can form. However, lacki, initially hot water may be less likely to supercool than cold water. Therefore ice formation occurs at different final temperatures in hot and cold water.
• Different definitions of the term "freezing". Is it the physical definition of the point at which water reaches 0 C, or the point at which the water forms a visible surface layer of ice, or the point at which the entire volume of water becomes a solid block of ice?
• The material freezing in question. Mpemba's inital observations were with ice cream mixtures, not water. The anecdotal evidence for the Mpemba effect came from a variety of ice cream manufacterers and the food processing industry worldwide, for a variety of water containing foodstuffs.

The effect was known to ancient and medieval scientists such as AristotleAristotle ( Greek Αριστοτλης Aristotelēs) ( 384 BCE March 7, 322 BCE) was a Greek scientist and philosopher. Along with Plato, he is often considered to be one of the two most influential philo, Francis BaconFor others individuals named Francis Bacon see: Francis Bacon (disambiguation Francis Bacon, 1st Viscount St Albans ( January 22, 1561 April 9, 1626), more commonly known as Sir Francis Bacon achieved fame as an English philosopher, statesman, and essayis and René DescartesRene Descartes ( IPA: rne. dekt) ( March 31, 1596 February 11, 1650), also known as Cartesius worked as a philosopher and mathematician. While most notable for his groundbreaking work in philosophy, he has achieved wide fame as the inventor of the Cartesi. Aristotles's explanation was that this was due to a physical property he called antiperistasis, defined as "the supposed increase in the intensity of a quality as a result of being surrounded by its contrary quality". He used the concept of antiperistasis to prove that human bodies and bodies of water were hotter in the winter than in the summer, a prediction that was later disproved by Medieval and Renaissance observations. As the explanations of the freezing effect lacked a testable theory, modern science had reduced the observations to folkloreFolklore is the ethnographic concept of the tales, legends, or superstitions current among a particular ethnic population, a part of the oral history of a particular culture. The academic study of folklore is known as folkloristics. The concept of folklor.

Mpemba's story is often given as a cautionary parable to those who reject theories or experiments solely because they seem counterintuitive, or contradict accepted theories, or because their proponent is not an expert. In the six years between Mpemba's discovery and his publication, his ideas were rejected on a number of occasions by his physics teachers and other authorities, and it was only the reproducibility of the effect by himself and others that drove Mpemba to persist against this resistance.