The unusual properties of ordinary water or a paradox Mpemba - real or fake

Water - the source of all life on Earth. If you look at the chemical composition, it is possible to think that it is extremely simple, and therefore, no unique properties does not possess. But it is not so. In fact, ordinary water more than once surprised and still surprised scientists with their unusual properties. In this article I want to tell you about the so-called paradox of Mpemba - when hot water freezes faster than cold. So, let's begin.

History Paradox

In fact, this effect was observed even scholars such thinkers as Aristotle, F. Bacon and R. Descartes. But in modern physics, this paradox is listed under the name E. Mpemba which is still a student in 1963, puzzled teacher of physics very simple question:

Why is it warm ice cream freezer froze faster than cold?

On the teacher replied that he (the student) has opened a new physics - Physics Mpemba.

Already a high school pupil inquisitive student asked about the water Prof. D. Osborne (who was invited from college in Dar es Salaam, to conduct lessons in physics), which was:

"If we take two identical containers and place them in water in a warm temperature with 35 degrees Celsius and the second temperature with hot 100 degrees Celsius, the second container (hot) formed ice faster. Why it happens?"

Professors are interested in this topic and in 1969 published a joint scientific work of students and professors in the journal Physics Education. It is since this effect is called the paradox Mpemba.

Interesting?! Then let's look at why this is happening and it's true or not.

The scientific explanation Mpemba effect

So Mpemba paradox states that hot water freezes quicker under certain conditions than the cold, although in this case it must pass cold water temperature during the cooling process.

Explanation of this paradox was made just a huge amount, and the most logical explanation seemed recently according to which:

Part of the hot water banal simply evaporate, thereby decreasing its total amount, and hence is faster solidification process.

But the research group of Nanyang Technological University of Singapore, which is headed by chemist Xi Zhang, made a statement that they have solved this riddle, but so far only in theory.

It turned out that the secret lies in the amount of energy stored in the hydrogen bonds between water molecules.

We all know with you that a water molecule consists of two hydrogen atoms and one oxygen atom. And these molecules are connected by hydrogen bonds, and in the heating process data communication are stretched, ie, store energy.

And it turns out that in the cooling process occurs tightening these ties, which leads to the release of energy, and thus to further cooling. But once again, that this is only theoretical calculations.

In fact, the paradox - a fake

But the majority of the scientific community tend to believe that this paradox is only the scientific fake and the whole secret lies in the thermal conductivity, namely:

So, if we'll take the two vessels, and put it in the freezer refrigerator (where it was seen by the effect) then the only option when manifest Mpemba paradox - if it is in the chamber of the refrigerator will be present crust of ice. In this embodiment, cold water glass will be cooled entirely by the cold air in the chamber.

But the vessel with hot water is required to peel ice melted the thus providing much better heat conduction with receptacle by contact with the evaporator, and this will give accelerated cooling liquid, and consequently it will freeze faster.

And as they say, is no secret no more.

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