Why is ice so slippery?

Question

Scientific answers PLEASE

Answer 1

(m)

For many years scientists have tried to understand the unique properties of ice in terms of the behavior of the molecules in the topmost layer. However, despite extensive studies the exact structure and dynamical motion of the individual water molecules at the ice surface have remained elusive. An international team of physicists (J. Braun, A. Glebov, A. P. Graham, A. Menzel) in the group of Peter Toennies at the Max Planck Institute for Fluid Dynamics in Göttingen have used the scattering of very low-energy He atoms for the successful analysis of the structural arrangement of water molecules on the ice surface and have also gained direct information on their vibrational motion. The results of these experiments, published in the March 23 issue of the Physical Review Letters [80, 2638 (1998)], indicate that the molecules are surprisingly mobile which explains many peculiarities in the interactions of ice with its environment.

Why do solid ice crystals have a melted surface-layer at temperatures far below the bulk melting point 0°C, that allows us to ski, skate and slide so easily; Why do two pieces of ice, when put together, adhere and become one; Why are different molecules in the earth stratosphere easily trapped on the surface of ice particles, where they can react, with consequences such as depletion of the ozone layer? This wide variety of intriguing questions have made ice one of the most frequently studied materials. However, until now, no definite answers to these and many other questions have been forthcoming since all of the attempts to gain information on the microscopic structure of a single crystal ice surface have failed. Very recently, even the powerful method of electron diffraction, routinely used in surface structure analysis, failed to provide any clear evidence on the structural arrangement of the topmost layer of ice. The group of scientists from the Lawrence Berkeley National Laboratory, Free University in Amsterdam, and the University of Pierre and Marie Curie in Paris [Surface Science 381, 190 (1997); also see report of Charles Seife in Science 274, 2012 (1996)] have suggested, on the basis of theoretical simulations, that the uppermost water molecules vibrate so strongly that a coherent diffraction pattern cannot be observed.

In the attempt to resolve this problem the researchers in Göttingen have employed low-energy helium atom scattering. This technique has the advantage of being completely nondestructive and exclusively sensitive to the topmost layer of crystals. Since the (111) surface of platinum has nearly the same lattice spacing as ice, it was used as a template on which single crystal ice films of 10-100 nm thickness were grown. Only after cooling the surface to 30 K was it possible to observe a sharp intense series of diffraction peaks. These not only provide information on the lattice spacing and arrangement of the first layer molecules but also indicate at least a partial alignment of the hydrogen atoms (ferroelectric ordering) at the surface.

A further advantage of the He atom scattering technique is that with the same equipment high-resolution time-of-flight energy loss and gain spectra can be measured. These spectra provide information on the frequencies and wave-lengths of the collective vibrations (phonons) at the surface. As the crystal was again cooled down to 30 K, a very intense inelastic peak emerged from a strong multiphonon background. This intense inelastic peak was simulated with a theoretical model which allowed its assignment to a special very large amplitude in-plane shearing motion of the surface molecules. At higher temperatures, this motion becomes increasingly enhanced leading to a high density "phonon bath" and ultimately individual molecules will break away from their original sites. This explains the liquid-like topmost layer as well as the difficulties experienced in the electron diffraction experiments.

Answer 2

Ice contains neatly, tightly packed water molecules. Because of the tightness of the molecules, the surface is smoother because there are less bumps, and thus the surface tension decreases and results in a drastic reduction in friction, hence slippery. In comparison, an unsmooth strand of carbon chain such as glucose is less smooth, and thus have more friction than water.

As our hand does not bond with water molecules, the effects of the polar molecules matter little to us, and can thus be ignored.

Answer 3

well on reason is that when presure is exerted on ice it melts due to the fact that the liquid water is dencer then the ice so when compresed it liquifies. then the water lubricates the sufrface between the object and the ice so its slipery. its the reason ice skates work well they consentrate the pressure to create more lubrication adn reduce friction by the decreased surface area

Answer 4

ice feels slipery on touching b,coz by touching we apply presure which leads to dippression of fressing pt and it melts near the pt of contact thus reducing the friction

Answer 5

because the surface of ice become highly regular as such the friction coefficient decreased.

Answer 6

because water has no texture. if you threw sand in the water before freezing it would give more friction. even i can answer this and i'm definitly not a scientist lol!!

Answer 7

because the nucleaic acids in tap water subside with in the molecues. aka: peoples farts melt ice

Answer 8

cause it is frozen & your blood temp is hotter than which melts the ice

Answer 9

coz the water molecules comes in hexagon structure while cooloing it .

Answer 10

because when it melts, the water makes u slip