"A surprising pattern, much like the meshed teeth of a zipper, is frequently seen when floating ice sheets collide," said John Wettlaufer, professor of geology & geophysics and of physics at Yale. He and his colleague Dominic Vella of Cambridge University in England demonstrated the underlying principle for the observation. Further, they suggest that the process can work for any materials that share particular physical characteristics of thickness and flexibility.
"When two elastic sheets floating on a liquid collide, intuition leads us to expect one of two results — one sheet might be 'subducted' under the other, as we observe with the earth's crust, or the two might crush each other forming a field of rubble, as we observe in thick ice floes," said Wettlaufer.
The researchers describe a third possibility in their study published in Physical Review Letters. They show that sheets of ice, or in their experiments, sheets of wax, form a series of interlocking blocks -– termed "finger rafting" — that alternately ride over and under one another. It is a curiosity that has vexed scientists for over 50 years.
The natural patterns look like meter-wide rectangular zigzags, and only occur when both sheets of ice are roughly the same thickness. Their theoretical analysis was confirmed experimentally using flexible layers of wax on water to simulate the phenomenon. They demonstrated the relationship between the width of the resulting fingers and the material's mechanical properties.
"We show that this striking observation is a general and robust mechanical phenomenon that we can reproduce in the laboratory with floating materials other than ice," he said. "Our experimental results were consistent with the field observations."
According to Wettlaufer, the findings are relevant for a host of physical systems and, "The same principles might be used for designing nanomachine gears from appropriate materials." He points out that Tuzo Wilson, one of the founders of the theory of plate tectonics, was inspired by the resemblance of structures on floating polar ice sheets to the transform faults and other features of the Earth's moving plates.
Janet Rettig Emanuel | EurekAlert!
Tracing aromatic molecules in the early universe
23.03.2017 | University of California - Riverside
New study maps space dust in 3-D
23.03.2017 | DOE/Lawrence Berkeley National Laboratory
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences