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New Theory Explains Why Hot Water Freezes Faster Than Cold Water


In 1963, a Tanzanian scholar named Erasto Mpemba observed some thing odd while making ice cream. when he iced up his boiling-hot mixture, it cooled quicker than his classmate’s cooler mixture. This phenomenon was later published in a paper by Mpemba in 1969, and became known as the Mpemba effect. however to at the moment, nobody is quite sure how it works.

Now, scientists from the Southern Methodist university in Texas and Nanjing university in China have published a new paper in the journal of Chemical theory and Computation that seeks to provide a solution. They recommend that the links between hydrogen atoms and oxygen atoms of neighboring water molecules is probably the reason.

“We see that hydrogen bonds change when warming up water,” Dieter Cremer from the Southern Methodist university, one of the researchers, told ScienceNews.

He brought that in higher temperatures, more hydrogen bonds have been strong due to the fact the weaker ones were broken down. This caused groups of molecules to form into fragments that could realign into the crystalline structure of ice. For colder water, the bonds need to first be broken before this can take place.

But, the idea that hot water can freeze quicker than cold water stays controversial. another recent article in scientific reports from November 2016 said there has been “no evidence to aid meaningful observations of the Mpemba effect.” The authors added they have been “not gladdened by such a conclusion, indeed quite the other,” as the effect had verified to be engaging to “people of all ages and backgrounds.”

One major problem is that the effect is difficult to reproduce, even though that hasn’t stopped plenty of theories being put forward for how it would work. One is that the hot water may evaporate, which reduces the mass and amount of water to be frozen. another is that water at lower temperatures freeze from the top, while warm water freezes from the bottom, although that is contentious.

It’s absolutely still an interesting topic. Forbes notes that in 2012, the Royal Society of Chemistry even held a competition to discover the excellent explanation for the effect – with the winner thinking that “supercooling” was at play.

However exactly why it takes place, or even if the effect is actual at all, isn’t clear. perhaps this latest paper will provide a new solution, however the case is far from settled for now.

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