Why does ice slide?

Why does ice slide? And yes, although it may seem like a really silly question to you, why the ice is so slippery is one that has plagued the world of science ever since. More than two centuries ago. Why does he slip? If it is from a layer of surface water as it appears, why is it formed? How can it exist at a temperature below its melting point? How long does a melted survive? Where’s the difference between melting just a thin layer into a thicker streak or even a whole block?

Of course, the search for an explanation for each of these questions involved a long process in which many great minds contributed. your grain of sand. finally, study Published at the end of 2022, in which researchers from Complutense University of MadridI managed to put an end to this persistent problem. We tell you all about this puzzle, although it may seem simple to you, we assure you that it is not.

Historical dilemma

Although today the use of ice as a slippery surface is more focused on leisure, such as in snowboarding or ski resorts, in ancient times it was a resource used for the most arduous tasks. Thus, for example, in China, during the Ming Dynasty, around the fourteenth century, the slippery property of ice was used in Transfer procedures. Highways made of ice blocks made it possible to easily transport marble slabs weighing hundreds of kilograms from the mountains to Beijing.

As a result, the concern arose in individuals to find out what makes ice different from other solids and what property allowed it to be such a slippery object. Doubt remained over the years, up to the Victorian era of Great Britain, and The first investigation on.

Photograph of the Glindelwald glacier, the basis for Huxley, Henslow, Tyndall and Hooker’s study of reversion.

Armin Kobelbeck

The year was 1856 and evidence was found that the last glacier in the British Isles, which melted 10,000 years ago, was sliding down the mountains, giving rise to valley erosion. Scientists wondered Huxley, Henslowe, Tyndall, and Hooker Why did that happen And they took the initiative to study the behavior and characteristics of glaciers. To do this, they traveled to Switzerland that same year, where they conducted various studies focusing on Grindelwald glacier.

Although their results did not focus on the slippery property, they coined the term first cooling Such as the property of ice that allows it to quickly melt and refreeze, as well as important advances in the study of friction that laid the foundations for the theories of later scientists in the field. In reality, His work was so important that the research was published In one of the first issues of the magazine natureAnd In November 1880.

Forcing rain

From studies of retraction by British physicists, a consensus theory emerged that the ice was able to slide due to the presence of surface layer of water Very fine, with a thickness equivalent to one hundredth of a strand of hair. However, the reason for its formation was something somewhat more obscure, and several eighteenth-century scholars, some already well-known at the time, attempted to Put an explanation propose different hypotheses.

First of all, Michael Faraday, famous for his studies of electromagnetic induction, proposed that fusion occur Spontaneously It is unique to snowboarding. However, this means that the ice has changed to a liquid state at a temperature below its melting point, which is contrary to the basic laws of thermodynamics. Therefore, the acceptance of the idea was disastrous.

Known for his great studies in the field of electromagnetism, Michael Faraday raised the idea that ice melts spontaneously on contact with objects.

Wellcome Library, London

For his part, engineer James Thompson confirmed, for his studies on the use of energy in transporting water, that ice is capable of melting and turning into a liquid. pressure effect. This approach led to the discovery of one of the most remarkable properties of ice because, in fact, unlike other solids that crystallize in this state, ice is able to melt when the pressure on it increases. This will be the case, for example, of stepping on a block of ice or squeezing an ice cube with your hands.

Based on this idea, John Jolly and Osborne Reynolds, pioneers in the field of hydrodynamics, stated that the displacement of any vehicle, for example, a skid, would I’d like to press to make it melt Thus, allowing easy movement on its surface and creating that slippery effect.

However, when it all seemed to become clear, the father of friction studies, Philip Bowden, suggested in 1950 that this melting was not due to pressure, but rather, The heat generated by friction For the vehicle on ice, it made it increase its temperature and melt, thus respecting the laws of thermodynamics.

The result: a whole lot of theories

In this way, though it seems somewhat exaggeratedly extended in time, the dilemma is whether the ice has slid by friction or by the pressure exerted. for several years. More specifically, until the end of 2022 when a group of scientists from Complutense University of MadridIn cooperation with Autonomous University of Madrid and the Marie Curie Sklodowska University in Lublinin Poland, putting an end to the mystery.

Using computational methods, they investigated simulate the movement of atoms As a solid slides over the surface of the ice it specifically observes the movement and behavior of each of the particles and the way in which one or the other melts. ResultsPublished in the journal Proceedings of the National Academy of Scienceswas startling, because they decided that, to some extent, each of the hypotheses raised was true to some extent.