Slashdot Mirror
Make A Hole - And Sustain It Indefinitely
Mick Ohrberg writes "Florian Merkt, Robert Deegan, and Erin Rericha, all at the University of Texas, have shown that a hole created in a water and cornstarch mixture with a puff of air can be persistent if the mixture is shaken at about 120Hz with acceleration being in the 12g-25g range. The physics behind the phenomenon has not yet been explained."
Given that cornstarch and water is a shear-thickening fluid, and the vibration (at 15-25g no less) is certainly a shear force, this phenomenon is almost certainly due to the vibration causing the cornstarch and water to gain viscosity. This wouldn't necessarily give you a stable hole, though, so it's probably also helped by the cohesive forces in the fluid and some other effects, too.
I would guess that it's not that the scientists don't know why this is happening, just that their models aren't accurate/precise enough to predict it. Or maybe they left out some effect or force that is normally negligible in the models, but suddenly becomes important in this situation.
The waters "congealed" and this certainly looks like "congealed" to me. The waters also fell back again quickly enough to engulf a million soldiers cannon weapons out on the Saudi shore, which doesn't sound like enormous amounts of cornstarch. Four million people could only carry a limited amount of it along with their other supplies.
The most likely explanation is that "a strong east wind" was just that, and cold, too. People forget that the desert gets damn cold at night, cold enough for the natives to make ice and ice-cream without compressors or Peltier devices. If a very cold tornado-force wind, maybe like the downbursts that kill passenger jets, hit the Saudi edge of the crossing it would scoop out a trench towards the Egyptian edge and freeze the sides. When it all melted, the Egyptian edge would melt first, collapsing in a rush towards the Saudi edge and producing the effects described.
Even the bit about their wheels being taken off "so that they drove heavily" might find explanation in their axles shrinking faster in the cold than their wheels and/or their gorm [Webster] freezing up and changing its behaviour.
There are many sources besides the bible recording the event, including a couple of Phoenecian pillars which stood at each edge of the crossing. The Egyptian one had fallen down and was pretty badly eroded, and the Saudi one has been whisked off to a museum and replaced with a marker, but the surviving inscription commemorated Moses' crossing as a part of the glorious history of Solomon.
Since something corresponding fairly closely to the bible's description happened there, the pragmatic approach is to find a reasonable explanation for it.