Subscribe to our free daily newsletters
. Earth Science News .




Subscribe to our free daily newsletters



WATER WORLD
How does water melt? Layer by layer
by Staff Writers
Mainz, Germany (SPX) Dec 14, 2016


Ice melts as described in the text layer by layer. Image courtesy MPIP. For a larger version of this image please go here.

We all know that water melts at 0C. However, already 150 years ago the famous physicist Michael Faraday discovered that at the surface of frozen ice, well below 0C, a thin film of liquid-like water is present. This thin film makes ice slippery and is crucial for the motion of glaciers.

Since Faraday's discovery, the properties of this water-like layer have been the research topic of scientists all over the world, which has entailed considerable controversy: at what temperature does the surface become liquid-like? How does the thickness of the layer dependent on temperature?

How does the thickness of the layer increases with temperature? Continuously? Stepwise? Experiments to date have generally shown a very thin layer, which continuously grows in thickness up to 45 nm right below the bulk melting point at 0C. This also illustrates why it has been so challenging to study this layer of liquid-like water on ice: 45 nm is about 1/1000th part of a human hair and is not discernible by eye.

Scientists of the Max Planck Institute for Polymer Research (MPI-P), in a collaboration with researchers from the Netherlands, the USA and Japan, have succeeded to study the properties of this quasi-liquid layer on ice at the molecular level using advanced surface-specific spectroscopy and computer simulations. The results are published in the latest edition of the scientific journal Proceedings of the National Academy of Science (PNAS).

The team of scientists around Ellen Backus, group leader at MPI-P, investigated how the thin liquid layer is formed on ice, how it grows with increasing temperature, and if it is distinguishable from normal liquid water. These studies required well-defined ice crystal surfaces.

Therefore much effort was put into creating ~10 cm large single crystals of ice, which could be cut in such a way that the surface structure was precisely known. To investigate whether the surface was solid or liquid, the team made use of the fact that water molecules in the liquid have a weaker interaction with each other compared to water molecules in ice.

Using their interfacial spectroscopy, combined with the controlled heating of the ice crystal, the researchers were able to quantify the change in the interaction between water molecules directly at the interface between ice and air.

The experimental results, combined with the simulations, showed that the first molecular layer at the ice surface has already molten at temperatures as low as -38C (235 K), the lowest temperature the researchers could experimentally investigate.

Increasing the temperature to -16C (257 K), the second layer becomes liquid. Contrary to popular belief, the surface melting of ice is not a continuous process, but occurs in a discontinuous, layer-by-layer fashion.

"A further important question for us was, whether one could distinguish between the properties of the quasi-liquid layer and those of normal water" says Mischa Bonn, co-author of the paper and director at the MPI-P.

And indeed, the quasi-liquid layer at -4C (269 K) shows a different spectroscopic response than supercooled water at the same temperature; in the quasi-liquid layer, the water molecules seem to interact more strongly than in liquid water.

The results are not only important for a fundamental understanding of ice, but also for climate science, where much research takes place on catalytic reactions on ice surfaces, for which the understanding of the ice surface structure is crucial.

Research paper


Comment on this article using your Disqus, Facebook, Google or Twitter login.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
Max Planck Institute for Polymer Research
Water News - Science, Technology and Politics






Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
WATER WORLD
Extreme downpours could increase fivefold across parts of the US
Boulder CO (SPX) Dec 06, 2016
At century's end, the number of summertime storms that produce extreme downpours could increase by more than 400 percent across parts of the United States - including sections of the Gulf Coast, Atlantic Coast, and the Southwest - according to a new study by scientists at the National Center for Atmospheric Research (NCAR). The study, published in the journal Nature Climate Change, also fi ... read more


WATER WORLD
Fukushima costs to double to nearly $190 bn: government

Canada buys new Airbus search and rescue planes for Can$2.4 bn

Urgent appeal for supplies after strong Indonesia quake

Syrian crisis altered region's land and water resources

WATER WORLD
Decoding cement's shape promises greener concrete

Shape matters when light meets atom

NASA awards contract for refueling mission spacecraft

Earth's 'technosphere' now weighs 30 trillion tons

WATER WORLD
Fishery bycatch rapidly driving Mexico's vaquita to extinction

2016 see mixed results for ocean health

A fish adapts quickly to lethal levels of pollution

Why cryptophyte algae are really good at harvesting light

WATER WORLD
Most of Greenland ice melted to bedrock in recent geologic past

Climate change likely caused deadly 2016 avalanche in Tibet

Greenland's ice-free past exposes sea level rise danger

Polar bear numbers to plunge a third as sea ice melts

WATER WORLD
Australia's Rinehart, China group win cattle empire bid

Soil pHertility mapped across the world

Common pesticides more harmful to 'good' insects than thought

Climate change battle heats up for Australian winemakers

WATER WORLD
45,000 left homeless after Indonesia quake

Second strong quake hits off Solomon Islands: USGS

The sea roils and life returns

Rescuers scrabble for survivors as Indonesia quake kills 97

WATER WORLD
Mobile money lifts Kenyan households out of poverty

Mali rivals must stick to peace deal: French minister

Fidel Castro's military forays in Africa

US seeks UN arms embargo against South Sudan

WATER WORLD
Study: Peripheral vision vulnerable to uniformity illusion

Secrets of the paleo diet

Human ancestor 'Lucy' was a tree climber, new evidence suggests

The role of physical environment in the 'broken windows' theory




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement