Translated material
Self-organization in a Petri dish
Russian physicists almost accidentally discovered a new form of self-organization in hydrodynamics. The discovery was made by a group from the Laboratory of Macrokinetics of Nonequilibrium Processes of the Department of Wave Phenomena of the Scientific Center for Wave Research of the Institute of General Physics of the Russian Academy of Sciences under the leadership of Georgy Shafeev.
The main directions of the laboratory's work are the production of nanoparticles and nanostructures on the surface of metals using laser ablation. And in this experiment, physicists studied the process of etching an aluminum plate in alkali. A well-known reaction from school during which hydrogen is released. The plate was etched, part of which was previously structured with a laser beam.
First, a plate was placed in the alkali, on which a square area was processed. Of course, on a laser-treated surface the process goes faster and more hydrogen bubbles are released. And here an interesting effect was discovered: rising hydrogen bubbles drift in the area of higher concentration of bubbles and are located along the diagonals of the square, forming a clearly visible pattern.
Of course, other forms of laser-treated areas were then tested. The picture is the same: the bubbles collect along the bisectors of the etched area. Moreover, if you draw a spiral on aluminum with a laser, the bubbles cause the entire volume of the liquid to rotate.
An article with the results and a theoretical model of the phenomenon based on the Bernoulli equation has been accepted for publication in the journal Phys. Rev., and its electronic preprint is available on Arxiv.org [1].