Artful Science
» About This BlogArchive → August, 2011
Banking On A Bunker To Save Britain’s Film
If I had to marry an inanimate object, I would not choose the Berlin Wall as Eija-Riitta has, but I might be tempted by a bunker, possibly the Boros bunker, whose dark history has been reclaimed by great art.
So you can imagine that I was super interested in a recent Guardian
article about a new archive for the British Film Institute, which will be located on top of the site of an old nuclear bunker.The BFI is facing what’s already a become a major problem for many who possess collections of early cinema: How do you keep 450,000 cans of film from breaking down, particularly when the film is made of cellulose nitrate, a plastic not known for its longevity?
When cellulose nitrate breaks down, it causes the release of nitric acid, which can accelerate degradation in nearby film. Eventually all the degradation results in a gooey or powdery mess where there was once a fantastic film.
The BFI’s spokesperson Brian Robinson told me that in the new archive, fragile film will be kept at -5 C, which is “down a notch” from the previous temperature (3-4 C) that the film was stored at. According to studies done at the BFI, Robinson says that the cellulose nitrate degradation will “be arrested.”
I can’t imagine that it’s ever possible to completely
arrest degradation, but I’m guessing the drop in temperature seriously decreases the rate of chemical breakdown.Finally, Robinson says the new £12 million facility will be well-ventilated, which I presume will suck away any amount of nitric acid that has managed to percolate off the valuable film.
The Peculiar Life Of The Dead Sea Scrolls
After spending more than two thousand years in peaceful hibernation, the Dead Sea Scrolls (DSS) have had a rough six decades. Discovered in several dry caves near the Dead Sea from 1947 through 1956, the texts experienced a series of travel and conservation adventures that border on mishandling, says Ira Rabin, a staff scientist at Germany’s Federal Institute for Materials Research and Testing (BAM).
Rabin has published several scientific papers on the Dead Sea Scrolls, which have historical and religious importance because they contain early versions of the Judeo-Christian Old Testament as well as other important Jewish writings. I recently met Rabin at a cafe in Berlin, where she described to me the potpourri of treatments that these texts—most of which are written on animal skin parchment–have received since their discovery.
The Dead Sea Scrolls have been covered in castor oil and glycerin as well as plastic consolidants (the latter of which is particularly unwise because no plastic stays in good shape for more than a few decades). Other treatments include Fuller’s Earth, a clay-like material, and being attached to glass plates using adhesive tape.
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Are Crop Circles Made By Microwaves?
If you believe that crop circles are a form of art made by rogue (human) sculptors, then you’ll probably want to read Richard Taylor‘s fascinating piece in Physics World about the science of making these curious farmland imprints.
If you can’t get past the PW paywall, check out my column in this week’s Newscripts about his quirky work on crop circle science.
In particular, Taylor thinks artists are using hand-held microwave magnetrons (I kid you not!) to make modern-day crop circles and he comes up with a pretty convincing argument to back up his sci-fi-sounding theory.
Conspiracy theorists may not buy Taylor’s logic since it doesn’t involve aliens (they’ve already accused Taylor of being in cahoots with US, UK and German spy agencies). But I like the microwave theory as much as the one proposed by Australian’s attorney general: that stoned wallabies are making crop circles in poppy fields down under.
The PEG In Sweden’s Vasa Warship
The vessel took four years to build and was armed with the highest tech weaponry available in 17th-century Sweden, but the four-story, top-heavy Vasa warship sunk before it managed to sail a nautical mile out of Stockholm’s harbor. That was 1628.
When the ship was pulled out of the water 333 years later in 1961, archeologists found all sorts of well-preserved goodies on board, as well as a hull in excellent shape. The wood had mostly managed to avoid two major evils: Degradation via wood worms (probably because the ship had sunk when it was still brand new) and degradation via microbes (the quirky bacteria that could survive in Stockholm’s particularly polluted harbor weren’t much interested in snacking on wood).
Letting the boat dry out would have been a death sentence for the gigantic artifact, since water-logged wood tends to shrink and warp as the water evaporates away, explains Martin Nordvig Mortensen, a researcher at the National Museum of Denmark, who is studying the degradation of the Vasa’s wood. (The vessel is located in Stockholm at the Vasa Museum).
Instead of letting the boat dry out, conservators sprayed the Vasa with a polymer called polyethylene glycol (PEG) until the ship was entirely saturated. (This took 17 years of spraying!) Since PEG doesn’t evaporate away upon drying, the wood is thus stabilized against warping. (Incidentally PEG has a curious spectrum of other applications, such as in theater smoke, toothpaste, antifreeze and personal lubricant.)
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Dredging Up A Dredge In The Yukon
When we embarked on what was possibly a harebrained, 406 km-long vacation canoe trip along the Yukon River in Northern Canada, I wasn’t particularly expecting to encounter a conservation site.
I was wrong: Our final destination on the Yukon River was Dawson City, the site of the Klondike gold rush in 1896. By 1898 the city had swelled to 40,000 people. Now there are now about 1000 inhabitants left and many abandoned turn-of-the-century buildings still left to restore.
But actually the most impressive conservation site was that of Dredge No. 4, a lackluster name for a colossal machine built in 1912 to sift gold out of the gravel, using the same principle as the folks who panned for the precious metal in streams–albeit at a rather larger scale.
The monster Dredge No. 4 is 8 stories high and 2/3 the area of a football field.
Since gold is 19 times heavier than water, the easiest way to separate gold from gravel is to dig up some ground, put it in a bowl of any size, shake everything back and forth in water and wait for the gold to sink to the very bottom of the wet mixture by means of gravity. Then you pour off the water and swipe off the top layer of gravel and presto there’s your gold nugget at the bottom of the bowl (or in my case, a single, barely visible flake of gold that garnered a rather sympathetic look from the teacher when I took a brief gold panning course).
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