Scientists log newfound understanding of water's responses to changing temperatures

October 16, 2017, New York University
Credit: George Hodan/public domain

A team of chemists has uncovered new ways in which frozen water responds to changes in temperature to produce novel formations. Its findings have implications for climate research as well as other processes that involve ice formation—from food preservation to agriculture.

"The freezing and melting of ice are among the most common events on Earth," explains Michael Ward, a professor of chemistry at New York University and one of the co-authors of the paper, which appears in the journal Proceedings of the National Academy of Sciences (PNAS). "These processes are surprisingly complex, however, and are not well understood because of the number of variables involved. Our findings reveal some unusual dynamic properties of ice surfaces in contact with liquid when the isotopic compositions of the solid and liquid differ."

The paper's other authors include Ran Drori, an assistant professor at Yeshiva University; Miranda Holmes-Cerfon, an assistant professor at NYU's Courant Institute of Mathematical Sciences; Bart Kahr, a professor in NYU's Department of Chemistry; and Robert Kohn, a professor in NYU's Courant Institute.

Understanding the dynamics of ice crystallization—otherwise known as ice formation—is vital in not only , but also in several industries: mitigating frost damage in agriculture and construction, optimizing , and understanding its impact on roads, runways, and rails.

In the PNAS study, the researchers focused on multiple forms of water, and, in particular, water containing different isotopes of hydrogen—their differences in neutron count produce distinctions in atomic mass. These forms included light, or "normal," water (H2O) and "" (D2O), with deuterium (D) increasing the mass of water compared with normal water.

It's long been known that different isotopes confer different properties on these distinct kinds of water—most notably different melting points. H2O begins to melt at zero degrees Centigrade (32 degrees Fahrenheit) while D2O does so at 3.8 degrees Centigrade (nearly 39 degrees Fahrenheit).

The variance in melting point is significant. For example, Antarctic or Greenland ice cores are composed of both H2O and D2O. As a result, they were frozen, and melt, at different temperatures. This property is used to estimate global temperatures over past millennia.

This raises the question the researchers focused on: What happens when water types with different freezing and melting points interact?

Here, the scientists found that, under conditions where the temperature was controlled precisely, the surface of a D2O crystal contacting liquid H2O assumed a scalloped appearance, with these "wavelike" features oscillating for hours.

Although the NYU team could not simulate all aspects of the oscillating features, they speculated that they reflect a range of phenomena: a complex interplay of exchange of light water for heavy water in the crystal, slight differences in the melting temperature along the scalloped interface, and heat transfer along the wave-like scalloped ice surface.

"If these processes can be unraveled completely, it may advance our understanding of the properties of ice that are important in numerous arenas, including climate research, frost damage in agriculture and construction, glacier dynamics, and food preservation," observes Ward.

Explore further: Scientists characterize the phase transitions of melting ice layers

More information: Ran Drori el al., "Dynamics and unsteady morphologies at ice interfaces driven by D2O–H2O exchange," PNAS (2017).

Related Stories

Study finds support for new forms of liquid water

April 4, 2017

Putting water in a (really) tight spot and cranking up the pressure could reveal new sides of its already mercurial personality, says a new international study co-authored by chemists at the University of Nebraska-Lincoln.

Water, water—the two types of liquid water

November 10, 2016

There are two types of liquid water, according to research carried out by an international scientific collaboration. This new peculiarity adds to the growing list of strange phenomena in what we imagine is a simple substance. ...

Water exists as two different liquids

June 26, 2017

We normally consider liquid water as disordered with the molecules rearranging on a short time scale around some average structure. Now, however, scientists at Stockholm University have discovered two phases of the liquid ...

Recommended for you

Scientists create diodes made of light

March 16, 2018

Photonics researchers at the National Physical Laboratory (NPL) have achieved the extra-ordinary by creating a diode consisting of light that can be used, for the first time, in miniaturised photonic circuits, as published ...

Quantum speed limits are not actually quantum

March 15, 2018

Quantum mechanics has fundamental speed limits—upper bounds on the rate at which quantum systems can evolve. However, two groups working independently have published papers showing for the first time that quantum speed ...

Thermally driven spin current in DNA

March 15, 2018

An emerging field that has generated a wide range of interest, spin caloritronics, is an offshoot of spintronics that explores how heat currents transport electron spin. Spin caloritronics researchers are particularly interested ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.