October 10, 2008
A bit of household science in the New York Times this week has wrecked my decades-old reverence for the cast-iron skillet. That’s according to data from the kitchen of Harold McGee, the great foodie-chemist and author of On Food and Cooking – a book that’s nearly as important to your kitchen as a decent chef’s knife.
McGee decided to settle a question that I thought I knew the answer to: In pans, what material handles heat best? He tested five skillets ranging in price from trusty $25 cast iron, through various mid-range varieties of aluminum, on up to a steel-coated copper pan that topped $400.
Now, I’ve always felt a kind of earthy piety when cooking with my trusty cast-iron skillet, which is going on 15 years old. Whether it’s delicately crisping a grilled cheese or setting off the smoke detectors over blackened salmon, I’ve always congratulated myself for sticking with its old-fashioned, even-heating perfection in the face of modern nonstickiness, metallurgical trickery, and charming pastel enamels.
So imagine my surprise. McGee’s “point and shoot” thermometer (forget new pans, I want one of those) indicated the cast iron pan was 100 degrees cooler at its edges than in the center. Pretty much every other pan design heated more evenly (and most more quickly) than cast iron. At first I didn’t want to believe, but the accompanying photos of toasted parchment were devastating.
Along the way, McGee discovered why butter does a better job than oil at keeping food from sticking, and turned up a principle called Bénard-Margoni convection to explain the ripples that appear in hot oil and look like the “legs” in wine running down a glass.
Three of McGee’s skillets had nonstick coatings – something I’ve sworn off. They’re a Catch-22 of annoyances: First, food always sticks to nonstick coatings. And second, you have to spend the rest of the evening waving a limp plastic scrubby at the problem for fear of further damaging the coating that doesn’t work in the first place. (Sure enough, McGee saw nicks appear in the nonstick armor of two pans during his experiments.)
Which leaves my only remaining point of pride with cast iron: When you do hopelessly burn a quesadilla, frittata, or korma into the bottom of your pan, you can at least attack it with steel wool and elbow grease.
(Image: H. Powell)
October 8, 2008
The 2008 electoral campaign has now brought us three debates. After 270 minutes of argument, the word “science” or “scientists” has been used approximately four times.
That would be three times in the first presidential debate*** (transcript), zero times in the vice-presidential standoff, despite the candidates being asked point-blank their views on climate change and its causes (transcript), and approximately once in the second debate.****
Perhaps we’ve reached the point where science is so ingrained in our culture that we don’t need to say its name. All four candidates spent plenty of time on economics and energy independence – two areas in which science and its city cousin, technology, are the bedrock of the discussion.
But then, if we don’t ever talk about science, how do we maintain or regain our country’s focus on scientific literacy, and train new experts in science’s ever-shifting frontiers? The words “education,” “teachers,” and “students” have been almost as rare in debate transcripts as science.
At least we can thank the National Science Foundation and Science magazine for encouraging people to think of new ways to imagine it. Their six-year-old Visualization Challenge rewards scientists and science outreach for finding compelling images and videos to get people to pay attention to research. The 2008 winners were announced at the end of September.
Above, the winner in photography is an electron micrograph of katydid-colored diatoms clinging to a hair-sized invertebrate in the Mediterranean Sea. Diatoms like these may produce as much as 40 percent of the world’s oxygen.
Points for whimsy go to a beetle’s tea party depicted in “Alice’s Adventures in Microscopic Wonderland,” the winner in Informational Graphics. Other memorable images show word linkages in the Bible and Op-art results of an experiment in polymer science.
I particularly loved the attempt by some German computer scientists to describe the shortcomings of current virus protection software and propose a next-generation solution. The team won an honorable mention in Non-Interactive Media for their cartoon short “Smarter than the Worm.” It’s charming to watch and so simply explained that you’re almost fooled into thinking you knew this material already. But you probably didn’t.
Here’s the vaguely Where the Wild Things Are-ish YouTube video, in English, for Smarter than the Worm. Watch it… then consider telling your politicians you’re ready for a renewed emphasis on science research and education.
Previous years’ Visualization Challenge winners are here.
(Image: NSF/Mario de Stefano/Second University of Naples)
***For the record, all three times by Barack Obama.
****This was when Obama noted that scientists were present at the start of the computing industry and implied we would need them again as we reshape the energy industry.
October 3, 2008
A new dinosaur discovered in Argentina had labyrinthine lungs that extended into hollows in its ribs, hips, backbone, and wishbone. It’s a rudimentary version of the lung system found in birds, where it allows breathing to be far more efficient than in mammals.
The dinosaur, named Aerosteon riocoloradensis this week in the open-access journal PLoS One, was a 30-foot long predator that raced about on two legs, though it lived some 17 million years earlier than Tyrannosaurus.
Disclaimer: Now, we at the Gist do realize that the Mesozoic world contained more than just rapacious bipedal predators. And we are looking forward to writing about, say, a peaceful, heavily armored, cycad-munching Ankylosaurus one of these days. We just can’t help it that these newsworthy lung pockets happened to be found in the bones of a large, scary meateater.)
In fact, the new-fangled lungs and the body they came from might not be a coincidence at all. Air sacs nestled in the bones of birds help them route air through their lungs in a one-way circuit, so that nearly all the air is exchanged with each breath. By contrast, our own system of sucking air into the front of our lungs, then pushing it back out again, leaves lots of old, stale air in our lungs on any given breath.
For birds, their bellows-like breathing system is the equivalent of those blowers that stick out of the hoods of 1970s muscle cars: it’s a ready supply of fresh oxygen they can use to supercharge their engines. That’s one reason why birds can fly so explosively. And if Aerosteon‘s lung structure gave it the same sort of ability, it might make sense that the system evolved in an animal that has to run down prey for a living.
Of course, scientists are always wary of a good argument without good evidence – that’s what they call an evolutionary Just-So Story. So lead author Paul Sereno and colleagues suggested a couple of alternative advantages that might have led to the appearance of Aerosteon‘s aerated bones (which, by the way, is what “aerosteon” means).
Shifting the lungs lower in the torso, they suggested, would lower the beast’s center of gravity and place it over the legs, perhaps making it a better runner. Another possibility is that pushing more air across moist lung surfaces helped with evaporative cooling. Overheating can be a severe problem for large animals that live vigorous lives in warm climates, since heat has a harder time getting out of a large body than a small one.
Now, does anybody have any tips on late-breaking Ankylosaurus research?
(Image: Todd Marshall/Project Exploration)
September 26, 2008
The Gist has been on a field trip in New York City this week, taking culinary detours into Italy, Korea, Lebanon, Ireland and the Sichuan province of China.
The Grand Sichuan International in Chinatown is a living-room-sized restaurant with an invisible kitchen, a dozen tables, and a soft-drink cooler wedged against one wall. Grand or not, it’s where I learned the meaning of ma la, the Chinese name for a soup made of dried chilies and Sichuan pepper. It arrived as a steaming tureen, set before us on a portable gas burner and filled with a bright-red bubbling liquid. Crispy dried chilies – perhaps 40 of them – bobbed in the waves like radioactive minnows, and we eventually fished them out to keep the soup from getting any hotter.
But the real draw were the small woody flecks of Sichuan pepper floating in the broth. At first, these gave the soup a random and alarming crunchiness. But moments later the taste developed into a citrusy buzzing and tingling over my mouth and tongue. As it went on, the feeling almost perfectly balanced the heat from the chilies, mellowing it and sweetening it in waves that sloshed across my mouth. That’s ma la: “numbing hot.”
The nearest equivalent is the tingling you get from eating orange or lemon zest (or perhaps, the weird taste/sense as your tongue comes back to life at the dentist’s). But for me, the sensation brought back precisely a visit to a south Georgia barrier island some 15 years ago. I had searched the back dunes for a tree in the genus Zanthoxylum. Sometimes called “toothache tree,” the leaves are supposed to make your mouth go numb. When I found it, it was a short, stout tree covered with immense thorns and sporting leathery dark-green leaves. At the time I was disappointed that my mouth didn’t go completely numb, but the sensation was identical to the lemony fizz of my Sichuan hot pot.
Back home, a little reading turned up why. Sichuan peppercorns (or huajiao) are the dried seed husks of a few Asian species of Zanthoxylum (one of many neat botanical holdovers from the days before the Atlantic Ocean stood between Eurasia and North America).
Fortunately for us, ma la and Sichuan pepper have not escaped the notice of chemists, and a 1999 paper in Brain Research suggests why the spice can make our tongues feel so many things at once. The lemony taste and tingling sensations come from a half-dozen volatile oils, the most peculiar being something called hydroxy-alpha-sanshool. When scientists tested this compound (on rats), they found it activated several different classes of neurons, including touch-sensitive, cool-sensitive, and cold-sensitive receptors.
Sichuan pepper is in the citrus family and is unrelated to white, black, or red peppers. Importing the spice to the U.S. only became legal in 2005 after fears eased about its potential for transporting a citrus disease. So, if I arm myself with some Zanthoxylum berries and the right cookbook, might I be able to recreate my hot pot – and make my taste buds do back flips again? After my nose stops running, I’m going to try.
(Image: the toothache tree of North America, Zanthoxylum clava-herculis; amyb/Flickr)
September 22, 2008
Behold the fearsome Manospondylus: one of the largest, fiercest predators the world has ever seen. With a skull the size of a wrecking ball and teeth like scimitars it terrorized the Cretaceous fens, eviscerating plump vegetarians and kicking around the skinny ones like discarded soda cans.
What’s that you say? Sounds an awful lot like a T. rex? That’s because Manospondylus was T. rex’s original name – coined in 1892 before the monster acquired its rather more striking name (in 1905) and started getting into showbusiness.
The mixup is an example of a very basic problem in paleontology: How many species of dinosaurs were there, and how do we know we haven’t named something twice? Scientists have named about 1,400 dinosaur species, but slightly fewer than half of those actually merited their classification upon closer inspection. Fortunately, a new study by British paleontologist Michael Benton suggests that we’re getting better at catching these mistakes.***
According to the study, the modern rate of discovering new dinosaur species is a breakneck 30 species per year, about double the previous peak of dinosaur-naming, in the so-called “Bone Wars” of the late nineteenth century. But because paleontologists have discovered very high quality fossil beds – especially in North America and Asia – they’re now working with much more complete material.
If you’ve ever had trouble figuring out how many kinds of ducks you’re feeding at your local city park, you might relate to the problem paleontologists face. They’re usually trying to differentiate species based on characteristic bumps, fissures, and cavities they find on whichever bones someone has managed to dig up.
Imagine trying to tell a mallard from a pintail based only on the shape of its kneecap, and you get an idea what they’re up against. Manospondylus was named from two large but shattered vertebrae, while the first Tyrannosaurus was named, 13 years later, from a partial skeleton. It wasn’t until 1917 that the similarity between the vertebrae in the two separate finds was recognized.
As a result of the recent flurry of advances, Benton reports, we may be honing in on a guess of how many dinosaur species there really were. At the start of the nineties we guessed there might be 1,200 species, but after a decade of discoveries and some 300 new species, that figure has risen to perhaps 2,200. With only about 675 “valid” species on the books right now, that leaves some 1,500 entirely unknown dinosaur species to discover. Ladies and gentlemen, grab your rock hammers.****
(Image: Wikipedia/David Monniaux)
***Kind of incredibly, Benton suggests that whatever naming mistakes might be happening nowadays are partly the fault of – you guessed it – the media. From the paper:
The aims of this study are to explore the recent burst of dinosaur work and to resolve whether the new phase is illusory or not. It could be that palaeontologists are producing poor-quality work, perhaps fuelled in part by excessive interest from museums and the media worldwide
****We also recommend obtaining a Ph.D. in paleontology.