TUESDAY, MARCH 30, 2010

KLMNO

THE GREEN LANTERN

Achenblog

6washingtonpost.com/achenblog

Today, European physicists are scheduled to force two

super-energized beams of subatomic particles to collide. What can we expect? The following is excerpted from The Post’s online Achenblog:

Something to get physicists jumping

MARTIAL TREZZINI/ASSOCIATED PRESS

The hadron collider: light at the end of its tunnel?

They’re about to start smashing things up at the Large Hadron Collider, the huge particle accelerator outside Geneva. Just to play it safe, I’m going to remain over here in North America, keeping a large chunk of the planet between me and this experiment. No, I’m not worried that they’re going to blow up Europe. I’m just worried they’ll create a time warp and I’ll go back six

months and be forced to relive the health-care debate. Seriously, although there are some hand-wringers out there who prophesy the end of the world, there’s nothing to worry about. I’ve been to the LHC. I’ve been down in the tunnel. I’ve studied the beam line, the huge magnets, the detectors the size of small apartment buildings. What I can tell you with confidence is that it merely LOOKS like a doomsday machine. The most likely outcome of the experiment will be a lot of

excited physicists and a general public that wonders if it was all worth the money. For example, they’re going to try to create a particle called the Higgs boson. But as I understand it, under the best of scenarios the LHC experiments will merely detect patterns of particle decay that will hint that the Higgs had been momentarily present on the scene. Moreover, if we do find evidence of the Higgs, it’s not like we can necessarily do anything with this knowledge. This is basic research, not applied research. What we should really fear is that scientists won’t discover anything they don’t fully expect to discover. No one wants the LHC to come up with all the predicted particles. The scientists want to find things that catch them by surprise and that inspire new theories: “new physics.” No one wants to come to the conclusion that we’ve found out everything that we’re ever going to find out.

— Joel Achenbach

RD Pakouk wrote:

But if the physicists are excited, well, isn’t that enough? Because, you know, when we get excited we make quantum jumps. (Oh, yes. Physics humor. A bottomless well of mirth.)

SCIENCE NEWS

Bipedalism takes a big step backward

Human ancestors began walking more like humans and

less like apes long before modern humans began walking the Earth. Anew laser analysis involving footprints discovered in 1976

at Laetoli, Tanzania, suggest that 3.6 million years ago, homi- nids (proto-humans) were walking in a very humanlike way, extending their legs and using more-balanced foot mechanics than apes. Walking on two legs has been considered a key fea- ture of human evolution since Charles Darwin, but scientists have not agreed on when humanlike walking began. A likely time frame seemed to be about 2.5 million years ago, since that is when the earliest members of our species emerged. The new research places the start much earlier, when skele-

tal evidence suggests that human ancestors still spent signifi- cant amount of time in trees. The fossilized footprints from two and possibly three upright walkers in Laetoli were pre- served in muddy volcanic ash about 3.6 million years ago and may have been made by Australopithecus afarensis, the hom- inid species of the famed Lucy skeleton. Past analysis of the prints have focused on stride length and compared the look of the footprints to that of human prints, without coming to a definite conclusion. The researchers used laser scans to examine foot bi- omechanics of eight human volunteers walking normally and then with a crouched-ape stance. After creating three- dimensional models of those strides, they compared them to the Laetoli prints and found a clear similarity in the equal toe-heel balance of the human upright strides and the Laetoli prints. The crouched stance left much deeper toe imprints. “Based on previous analyses of the skeleton of Australo-

pithecus afarensis, we expected that the Laetoli footprints would resemble those of someone walking with a bent-knee, bent-hip gait typical of chimpanzees, and not the striding gait normally used by modern humans,” lead researcher David Raichlen, an anthropologist at the University of Arizona, said in a statement. “But to our surprise, the Laetoli footprints fall completely within the range of normal human footprints.” According to the study, which was published this month in the journal PLOS One, the “results provide the earliest un- equivocal evidence of human-like bipedalism in the fossil rec- ord.” The researchers, however, said there was no way to spec- ulate on how early that bipedalism developed.

—Margaret Shapiro

SCIENCE SCAN

KITCHEN MAGICIANS

Tofu to the rescue

“FUTURE FOOD” (PLANET GREEN, TUESDAYS AT 10 P.M.)

This new television series about ex-

treme cuisine is set at Moto, a restau- rant in Chicago. Like José Andrés’s Minibar in Penn Quarter, Moto is part of the molecular gastronomy move- ment, which pushes the limits of what is scientifically possible to do with food; it seems as if most recipes on the show end with the food being dipped into a vat of liquid nitrogen. The March 30 debut episode opens

with Moto receiving a sub-par ship- ment of fish. Forced to improvise, chef Homaro Cantu challenges his kitchen staff to create something that looks and tastes like fish but includes no sea- food. Cantu and his business partner, pastry chef Ben Roche, come up with frozen watermelon sashimi and scal- lops made of tofu. Declares Cantu: “That’s the best damn synthetic soy- bean scallop I’ve ever had!” The eco-friendliness angle — “Fu-

ture Food” is airing on Planet Green, after all — feels forced. In this week’s show, there’s a passing mention of overfishing. In an upcoming episode, the chefs try to “shorten the food chain” by creating a veggie burger made of what a cow eats. Let’s hope they opt for grains rather than hay.

— Rachel Saslow

DAVID NICOLAS/DISCOVERY

Pastry chef Ben Roche appears in the debut episode of “Future Food.”

K

by Nina Shen Rastogi

My local supermarket carries a dizzying variety of salt: “hand- harvested” sea salts, kosher salt, plain-old table salt, etc. Are any of these salts more eco- friendly than the others?

Gourmands and health nuts love debating the advantages of various types of salt, but environ- mentalists have typically been more concerned about the kind we apply to our roads than about the stuff on supermarket shelves. Some types of food salt are made in ways that are easier on the planet — but by the time they get to you, the benefits may have van- ished. There are two ways to get salt: mining it and harvesting it from naturally occurring saltwater. Most common table salt sold in

the United States is pro- duced via solution mining, which involves digging a well deep into an under- ground salt deposit, pumping in water to dis- solve the salt crystals and then drawing the brine up to the surface. The process is pretty mild, as mining opera- tions go, since it doesn’t pro- duce much noise, airborne pollu- tants or groundwater contamina- tion.

The salty solu- tion is then fed into a machine that resembles a giant pressure cooker, which evap-

orates most of the wa- ter; the resulting slurry

gets spun and heated un- til the salt is completely

Are some salts better than others?

dry. This method, known as vacu- um pan refining, is the most cost- ly and energy-intensive, but it creates a product that’s nearly 100 percent sodium chloride. (You can also get edible salt the old-fashioned way — by digging it out of the Earth in its mineral form — but in the United States, most of this rock salt is used for highway ice remov- al.)

The other way to cre-

ate food salt is by pumping seawater or briny lake water into a series of large, shallow ponds and leaving it to evaporate naturally. The process is very slow — it can take years for the sun and wind to turn saltwater into crys- tals that you can scoop up and package — but it has a clear envi- ronmental benefit in that it requires very little fossil-fuel input. With large-scale op- erations, wildlife is- sues may come into

play: Supporters say the ponds can provide sanctu-

ary for certain wetland spe- cies, such as flamingos and other birds; however, environ- mentalists have successfully pro- tested the establishment of indus- trial saltworks in parts of Aus- tralia and Mexico on the grounds that they could disrupt ecosys- tems at sea and on land. The liquid, or bittern, that remains after evaporation also re- quires special consider- ation, since in large, concentrated amounts it can be harmful to fish

The Green Lantern is a weekly

environmental column from Slate. Read previous columns at www.slate.com/greenlantern.

and other aquatic organ- isms.

Some solar sea salt is then washed and refined in a process that can be as en- ergy-intensive as vacuum pan refining. But most

gourmet sea salts are har- vested from evaporation ponds — sometimes with hand tools — and then treated very minimally before they’re pack- aged and sold. (At larger opera- tions, the salt is gathered using special tractors with scrapers.) So at least in terms of energy use and greenhouse gas emissions, those high- end salts would in- deed seem to be more eco-friendly than the common variety.

Of course, the flip side is that the fancy stuff may have traveled a long way to get to your neighborhood Whole Foods. At the moment, most artisanal salts are produced outside the United States, while regular table salt generally comes from domestic sources. Fig- uring out whether the sav- ings on the production side are enough to cancel out the impacts of the longer jour- ney would require a lot of data collection and num- ber-crunching. Either way, packaging could make a big

HOW AND WHY

Ivan Amato

Not a hole lot you can do to keep roadways smooth

aTHUMP-kaTHUMP. That’s the sound of rubber meeting potholed road. If

you’re the one kathumping, you’re probably adding a few staccato profanities to that street beat. None of this should blind you to the presence of nature’s grandeur in the mix. We’re talking here about the magnificent power of water and ice to defeat the pavement’s man-made mix of gravel, sand and asphalt. It may seem dumb as a brick,

but pavement is seriously complex stuff, even to materials scientists and civil engineers who get paid to know everything about constructed landscapes, including roadways. That gold in your wedding ring or glass in your window is mostly a single chemical composition in mostly a single molecular architecture. Compared with that simplicity, the asphalt concrete mix that makes up almost 90 percent of the nation’s roadways is as complex as human psychology. About 95 percent of your

typical city road surface is an aggregate of sand and stone crushed into pieces of many shapes and sizes. The rest is mostly asphalt, a sticky gunk that gets heated at paving time so it will flow like warmed maple syrup and coat all of those bits and pieces in the aggregate. Asphalt is what remains behind when crude petroleum is distilled and refined into fuels and basic ingredients for making chemicals. It’s also cheap, abundant and good at cementing the concrete mix into pavement you can drive on. At least until water and winter conspire to show the road who really is king. In the winter, water

perpetrates its street violence through a combination of its fluidity when it’s a liquid and its odd knack for expanding when it freezes, instead of contracting, as almost every other liquid does. The reason is simple chemistry. If you could get up close to a water molecule, it would have the shape of a Mickey Mouse head, in which two hydrogen atoms (Mickey’s ears) bond to a larger central oxygen atom (Mickey’s head). Like human partners, these atoms don’t share everything equally, including the electrons that are their bonds’ chemical

glue. The oxygen atom stakes a stronger claim on these electrons, so it basks in a negative charge, while its hydrogen buddies come off on the positive side. The combo of mouse-head angularity and polarized

where temperatures remain frigid in the winter rather than hopping over and under 32 degrees. Fewer freeze-thaw cycles mean fewer potholes. An anti-pothole tactic most

GERALD MARTINEAU FOR THE WASHINGTON POST

One idea for battling potholes is a patching material that contains a synthetic plastic tough enough to stop bullets.

electrical charge has consequences for the pothole phenomenon: When the temperature is above freezing, water molecules move around so fast that they don’t get locked into a specific arrangement by their electrical charge; this allows them to flow and assume the shape of any container, including pores in the pavement. Here’s where things get interesting chemistry-wise (and can lead to overtime for road crews): As water freezes, what was a mosh pit of molecular motion slows down enough that the frenzy no longer overcomes the attraction between positively charged hydrogens and negatively charged oxygens. These opposite charges align with one another in a rigid and, because of the molecule’s angularity, less compact way than when water is liquid; as a result, it takes up much more space. The resulting solid lattice of

ice occupies 9 percent more volume than the liquid from which it formed. In the cracks and pores of pavement (or inside

your house pipes), freezing water can exert 15 tons — tons! — per square inch of pressure on its surroundings. It’s like Samson’s ruinous pushing ploy on the pillars of the temple of Dagon. Numerous freeze-thaw cycles that come with snowy winters and nightly applications of de-icing salt multiply the damage. Little cracks become bigger ones become potholes become your neighborhood car gulpers. But that’s only part of the

story. Below the pavement, a related and often more damaging process can unfold. When water that has percolated all the way to the interface between the soil (or a crushed stone base layer above that) and the overlying pavement freezes there, that 9 percent expansion heaves the pavement upward and upsets the road’s basic support. Meanwhile, vehicles rolling on the now weakened roadway impose their own compression and tension that leaves wounds: millions of potholes. Ironically, potholing is less problematic in regions

often deployed for high-volume roads such as interstates, including the Capital Beltway, is to pay more — a lot more — up front for so-called perpetual pavements. These designs include expensive drainage systems, with more layers, better grading and sometimes pipes to carry runoff, but they still require intermittently milling off the top layer and replacing it with a new one, according to Chris Williams, a civil engineer at Iowa State University at Ames. He rates France as tops in the world for road quality because of its rigorous standards for pavement materials and design. In their own noble quest to help the nation better manage the annual plague of potholes, Williams and his colleagues have been trying to create the perfect patch, using piles of spent asphalt roofing shingles, which they chop into pieces and mix into various blends. Williams claims that the asphalt, granular topping, lime dust and fiber in the shingles improve the patches’ toughness and makes them last several times longer than the usual few months. He also is developing what he says should be more-affordable pothole-resistant pavements, using non-petroleum “bio asphalts” derived from waste materials such as corn stalks and switch grass. In tests, these pavement materials have proven to be more pliable and crack-resistant and, he says, better at keeping moisture at bay. Meanwhile, UCLA materials scientist Jenn-Ming Yang and his partners, including the City of Los Angeles, are also taking on potholes, which in L.A. form less from freeze-thaw cycles than from the city’s famously hellish traffic volume. Yang and his fellow pothole heads are banking on dicyclopentadiene, a byproduct of the petrochemical industry that can be turned into synthetic plastic that is tough enough to stop bullets. The researchers are looking into adding these materials into asphalt concrete patching mixes to produce tougher, less porous and much-longer-lasting road Band-Aids. It could be a while, though,

before such materials reach our streets. Until then: kaTHUMP-kaTHUMP.

health-science@washpost.com

Amato is a writer and editor based in Silver Spring.

difference. Many gourmet salts are sold in small glass bottles. As we discussed be- fore with regards to beer containers, glass is heavy and makes for more expensive trans- portation — and greater emissions of greenhouse gases. What about kosher salt? As with meat, the kosher designa- tion alone doesn’t make a differ- ence when it comes to environ- mental impact. Kosher salt can be extracted via solution mining or from seawater and processed via vacuum pan re- fining or solar evaporation. What makes salt kosher — or, more pre- cisely, suitable for use in the process of draining the blood from a ko- sher piece of meat — is the size of the par- ticles. Either the salt is raked during the refining phase so that the pieces come out larger and coarser or producers simply sift out

ILLUSTRATIONS BY MICHAEL

SLOAN FOR THE WASHINGTON POST

naturally occurring smaller gran- ules, which are then sold as table salt or else molded into things like water-softening tablets and animal feeding blocks. So there’s no reason that kosher salt should be better for the planet than reg- ular table salt — though it does make for a nice rim on your mar- garita glass.

ask.the.lantern@gmail.com, and check this space every Tuesday.

Science

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