Scientists from USA have developed a theory that uses the concept of shock waves, to explain the forms “wine tears”. Article accepted for publication in the journal Physical Review Fluids.
The glass of wine on the walls sometimes appear patterns resembling tears — these patterns are called “wine tears.” More than a century scientists speculated on what the “wine tears.” It is known that the mixture of water and ethanol can move up the glass due to the capillary effect due to surface tension.
When the wine covers the surface of the glass, it begins to evaporate, but the alcohol evaporates faster than water, leading to increased surface tension, which causes liquid to move up. At some point, surface tension forces cannot resist gravity, and the liquid drains back into the glass. This phenomenon became known as the Marangoni effect, in honor of Carlo Marangoni, who published his observations in 1865. However, while the nature of tears well studied, their form has remained a mystery to scientists.