Up and down on mobile sands
2005/12/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria
Mobile sands are dangerous mixes: sand, clay and water. Daniel Bonn, a physicist at the University of Amsterdam, says they are more dangerous when the water is salty than when it is sweet. Bonn, from a sample taken in Iran, revealed what was the physical mechanism that makes mobile sands so dangerous.
The first result of this research was the strong reaction of the mobile sands to external physical tension. In fact, the viscosity of the mixture decreases a million times more than increases the tension in the mobile sands. A person trapped in it, as it is pushed down, liquidates the bottom. If this liquid is saline, it also settles a few minutes after its liquefaction, which considerably increases the strength needed to get out of there. One of the trapped should make the force very slowly so that the water leaks slowly down.
According to Bonn, the functioning of the mobile sands makes impossible what is seen in films, that is, the sands cannot completely engulf a person. In short, the sedimentation process itself would keep the person from sinking.
