Physics to avoid splashing
2005/03/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria
When a drop hits a surface splashes out, small droplets. This fact is investigated at the University of Chicago. What to investigate, since there are many characteristics that influence this phenomenon, among others, the viscosity of the liquid, the pressure and the atomic weight of the gas of the medium in which the drop falls.
Researchers have found that the result is mainly due to the action of the gas around the gout and that, for example, as the pressure decreases, fewer splashes occur, and that there is a pressure below which no splashes come out. This pressure depends on the atomic weight of the gas: the higher the atomic weight of the gas, the higher the pressure needed to avoid splashing.
To study the splashes of the drops, they have dropped the drop from different heights in a closed chamber and have collected with a high-speed camera the moment when the drop hits a sheet. Each recording has selected variables that can influence splashes. Three liquids have been used, all of them alcohols: methanol, ethanol and 2-propanol.
The gas around the drop has also been modified, helium, cripton and sulfur fluoride have been introduced into the chamber, and at various pressures, between ambient pressure and 100 times lower pressure.
