Medium Viscosity Fluid Mechanicians Win Ig Nobel
This is old news by now, but eternal bloggish laggardliness is the price of having a job I can’t actually do in my sleep. Anyway, this year’s Ig Nobel physics prize has gone to an experiment demonstrating a concept near and dear to every* geophysicist’s heart, the ability of brittle materials to behave as fluids over long timescales:
The pitch was warmed and poured into a glass funnel, with the bottom of the steam sealed. Three years were allowed for the pitch to consolidate, and in 1930 the sealed stem was cut. From that date the pitch has been allowed to flow out of the funnel and a record kept of the dates when drops fell. The observations which appear in the illustration are brought up to date in table 1.
The viscosity of pitch is then calculated as Î· = (2.3 +/- 0.5)x10^8 Pa s, which is enormous compared to that of common liquids – water at 20Â°C has a viscosity of 1.0×10^-3 Pa s. It should be noted however that (ignoring superfluidity) it is close to the geometric mean of the range of values that physicists consider – the effective viscosity of the Earth is of the order of 10^20 Pa s (Stacey 1977).
Someone should show the pitch drop experiment to this guy, before he spouts his ignorant garbage again:
“You see any cracks in that [folded rock]?” he asked. “Instead of bending like that, it should have cracked.” The material “had to be soft” to bend, Mr. Vail said, imagining its formation in the flood. When somebody suggested that pressure over time could create plasticity in the rocks, Mr. Vail said, “That’s just a theory.”
Once again, I suggest you all go out and whack some silly putty with a sledge hammer. It’s the same rheological principle, illustrated in a slightly lower viscosity material that’s fun to play with.
Analysis by the authors of the Nature paper show Buitreraptor and Rahonavis, a fossil animal from Madagascar previously considered a primitive bird, form a southern branch of the dromaeosaur family tree.
This branch is distinct from Laurasian dromaeosaurids, including Velociraptor and some of the famous feathered dinosaurs from China. Birds are commonly thought to have evolved from this group.
The authors say the discovery Rahonavis and Buitreraptor have long and wing-like forelimbs could imply that flight evolved twice, once in birds and once among this group of Gondwanan dromaeosaurs.
Twice? For shame, Beeboid, forgetting the bats and bugs like that!
*Okay, fair’s fair: many excellent geophysicists were never convinced that ordinary mantle rocks could behave as fluids. But they didn’t come up with much beyond pure stubbornness and curmudgeonhood to support their arguments, and now they are dead, the end.