Last week I blogged about singing dunes, and this week there is more cool news about the peculiarities of sand. Seems that completely dry sand can swallow up objects whole, which may account for instances of people having vanished in the desert.
After puffing up ordinary sand by blowing air through it, the packing density (ratio of sand to total volume) was a nebulous 41 percent, down from 60 percent originally. At that point an object placed on the sand was quickly and completely swallowed up–the best part is the thin beam of sand that shoots up in the air as the sand snaps over the completely submerged object. (See the picture at the above link, fifth from the left.) Given where it finds itself these days, naturally the Army is very interested.