® DEMYSTIFYING EVERYDAY CHEMISTRY

DECEMBER 2009

Hollywood’s Special Effects Chemistry Behind the Scenes, p.5

Space Food: Dining 220 Miles Above the Earth, p.11 QUESTION FROM THE CLASSROOM By Bob Becker

A classmate recently reported on the element selenium. And then there are the ele- to bond carbon molecules into QHe said that selenium is an essential mineral in our diets ments hydrogen and oxygen. long chains known as proteins. and that humans and other animals could not exist without it. Then, They seem to be indispensable So, it is reasonable to assume another classmate reported on the element manganese with a similar to life. Not just life as we know it, that a “nitrogen-less” universe

result. I had never even heard of these two elements. So I was think- but life of any kind. Not only do would also be a lifeless universe. all elements f ro m ist o c k ing, what would life be like here on Earth without these elements? they play critical roles in adding How about selenium and to the complexity of carbon- manganese (mentioned in the If you consider all of But what if copper—or either based molecules, but they also question)? Trace amounts of A the elements that life selenium or manganese—had combine to make the most selenium are essential for the depends upon, you may come never been here to begin with? unusual compound—water. production of enzymes that are to the conclusion that we are Could life still have evolved? Liquid water is vital both as found in cells. Selenium defi- very lucky to be here at all. The For most of the elements listed a solvent—in which many of the ciency can lead to diseases, such human body contains roughly 40 below, I think the answer would body’s chemicals dissolve—and as thyroid disorders, psoriasis (a different elements. For other ani- be yes. If these elements had as an essential part of metabolic skin condition), and susceptibil- mals and plants, the list is very not existed, animals and plants processes within the body. ity to heart disease similar. But it’s easy to assume would have evolved to take No other liquid is and viral infections. that if any of these elements were advantage of the elements that known to do it Manganese plays a missing from our universe, sud- were available to them. as well. Water role in the liver, kid- denly our planet would become a There are a few elements that is—as far as neys, and the brain. lifeless wasteland. probably are critical to life. The we know—the In experimental If, right now, all of the first is carbon. Carbon atoms are only liquid that animals, manganese manganese and very good at bonding to one makes life pos- deficiency causes selenium were another and to other ele- sible. This is impaired growth, suddenly taken ments, such as oxygen why NASA’s skeletal abnormalities, and away, we would all and nitrogen. They do policy in its search for poten- defects in carbohydrate and fat be in a lot of trouble, so in chains and rings tial life on other planets metabolism. but that’s because we have and intricate arrays has always been to “fol- Beyond carbon, hydrogen, evolved to take full advantage that are the building low the water.” oxygen, and nitrogen, it is hard of the resources available here blocks of all organisms. Nitrogen would to say what other elements are on Earth. If there were no car- also probably make essential to life. What experiment For example, we depend upon bon on Earth, could sili- the short list of could be designed to see what copper, because somewhere in con, which is just below elements truly kind of life might have evolved our evolutionary history, this ele- carbon in the periodic essential to life. in the absence of any given ele- ment proved effective in certain table, fill the void? Silicon Nitrogen plays ment? Perhaps these are ques- biological catalysts that facili- has four bonding sites, just an important role in tions best left to science fiction tated chemical reactions in our like carbon, and it forms a plant chemistry, and it serves writers! metabolism. We can assume that few short chains, but not nearly past organisms that used copper enough to create the complexity in these catalysts stood a slightly of structures that life processes Correction: greater chance of survival than depend upon. Some science fic- In the October 2009 issue of ChemMatters, an error occurred in the caption those that didn’t. So, organisms tion novels have postulated plan- of Figure 1 (p. 8). The correct caption is: “When light is spread through a using copper continued to flour- ets populated by silicon-based prism, it reveals its constituent colors, going from purple to red.” ish and pass on their copper- life forms. Intriguing, yes, but the Also, the following reference was omitted by mistake from “Selected refer- ences” at the end of the article, “Where Do Chemical Elements Come From,” using genes to their offspring. chemistry just is not there. No by Carolyn Ruth: What started out as an evolution- other element seems to have the Sagan, C. Cosmos; Random House, Inc.: New York, NY, 1980 ary advantage has become a same capacity for life complexity survival necessity. that carbon possesses.

2 Chemmatters, DECEMBER 2009 www.acs.org/chemmatters ®

Vol. 27, No. 4 DECEMBER 2009

DEPARTMENTS FEATURES Question from the Classroom 2 Hollywood’s Special Effects: By Bob Becker How Did They Do That? 5 What are the chemical elements that are essential to life? By Diana Lutz Many special effects used in movies are based upon a wide range of Did You Know? 4 chemicals. Discover which chemicals are used to create fake snow,

Producing energy with carbonized chicken feathers; artificial skin, and explosions. jo e v is ko cil is air pollution as bad as cigarette smoke? The Science of Snowflakes: Profiles in Chemistry: J. L. Kiappes, Crystals from the Clouds 9 istock Silver Medalist in the 2004 International By Andrea Hazard Chemistry Olympiad 17 Snow crystals come in an incredible variety of By Christen Brownlee shapes, including wide flat plates, long thin

columns, and branched snow stars. Why is that so? k enneth libb r echt s

J. L. Kiappes describes what it’s like to e v

i

h

c

take part in the National Chemistry r

a

o Space Food 11 Olympiad and then the International c n s u By Kathy De Antonis , K Chemistry Olympiad. C TO IS Space food needs to be lightweight, compact, and require minimal prep- aration (given that you can’t cook Interested in Competing for the National Chemistry it in space). How do NASA food Olympiad? Here Is a Chance to Test Yourself! 19 scientists do it? By Arden Zipp Spanish translation Try to answer a question that appeared in the National Chemistry available online! nasa Olympiad in 2003. The Vinland Map: The Vikings’ Best Kept Secret 14 By Linda Zajac TEACHERS! find your complete The Vinland Map is either a 13th century map of America that pre-dates teacher’s guide Christopher Columbus or a clever fraud. Learn about the scientists who for this issue at have analyzed the map for the past 50 years and why they have not www.acs.org/chemmatters been able to solve its mystery yet.

Production Team Education Division Subscriber Information the cautions contained in the text, or from not Patrice Pages, Editor Mary Kirchhoff, Director Prices to the United States, Canada, and following standard safe laboratory practices. Cornithia Harris, Art Director Terri Taylor, Assistant Director, K–12 Science Mexico: $14.00 per subscription. Inquire Therese Geraghty, Copy Editor about bulk, other foreign rates, and back All rights reserved. No part of this publica- Policy Board issues at ACS Office of Society Services, tion may be reproduced, stored in a retrieval Administrative Team Ingrid Montes, Chair, San Juan, Puerto Rico 1155 16th Street, NW, Washington, DC system, or transmitted in any form by any Marta Gmurczyk, Administrative Editor Barbara Sitzman, Tarzana, CA 20036; 800-227-5558 or 202-872-6067 means, now known or later developed, includ- Peter Isikoff, Administrative Associate Ami LeFevre, Skokie, IL fax. Information is also available online at ing but not limited to electronic, mechanical, Steve Long, Rogers, AR http://chemistry.org/education/ photocopying, recording, or otherwise, without Technical Review Mark Meszaros, Rochester, NY prior permission from the copyright owner. Seth Brown, University of Notre Dame The American Chemical Society assumes no Requests for permission should be directed in David Voss, Medina High School, Barker, NY ChemMatters (ISSN 0736–4687) is published responsibility for the statements and opinions writing to ChemMatters, American Chemical four times a year (Oct., Dec., Feb., and Apr.) advanced by contributors. Views expressed Society, 1155 16th St., NW, Washington, DC Teacher’s Guide by the American Chemical Society at 1155 are those of the authors and do not neces- 20036–4800; 202-833-7732 fax. William Bleam, Editor 16th St., NW, Washington, DC 20036–4800. sarily represent the official position of the Donald McKinney, Editor Periodicals postage paid at Washington, DC, American Chemical Society. The activities in Ed Escudero, Editor and additional mailing offices. POSTMASTER: ChemMatters are intended for high school Ronald Tempest, Editor Send address changes to ChemMatters students under the direct supervision of Susan Cooper, Content Reading Consultant Magazine, ACS Office of Society Services, teachers. The American Chemical Society David Olney, Puzzle Contributor 1155 16th Street, NW, Washington, DC 20036. cannot be responsible for any accidents or © Copyright 2009 injuries that may result from conducting the American Chemical Society activities without proper supervision, from not Canadian GST Reg. No. 127571347 Cover photography courtesy of Richard RickItt and Mike CiesiElski. Printed in the USA Movie screen photo is from the movie True Lies (1994) in which a bridge explodes, throwing a truck in midair. specifically following directions, from ignoring

chemmatters, DECEMBER 2009 3 DID YOU KNOW?...DID YOU KNOW?...

Atomic Structure: Is Air Pollution as Bad as Cigarette Smoke?

Atomic Bonding: Producing previously unrecognized Agroup of air pollutants Energy with Chicken Feathers could have effects similar to harmful substances found in tobacco smoke, Louisiana sci- cientists in Delaware have more hydrogen than two other entists say. Inhaling these pol- Sdiscovered that carbonized materials—carbon nanotubes lutants may expose people to chicken feathers could be used to or metal hydrides—being stud- up to 300 times more harmful store vast amounts of hydrogen, ied for their hydrogen storage chemicals than from smoking a promising source of energy potential. one cigarette, they say. that may one day replace gaso- The scientists looked at Harmful air pollutants line in cars. chicken feathers because they called free radicals are atoms, ist o c k are very cheap. “It actually costs molecules, or fragments of mol- the poultry industry money to get ecules that are highly reactive “Persistent free radicals can rid of these feathers, so they are and damage cells in the body. stay in the air indefinitely, so you Chicken feather basically for free,” Wool says. They form during the burning are never going to get away from fibers are mostly “Using carbonized chicken of fuels or in chemical reactions them,” says Barry Dellinger, a composed of keratin, a feathers would only add about with other molecules in the air. chemist who led the team of sci- protein found in fingernails $200 to the price of a car,” Wool The reason they are so harmful is entists who made this discovery and hair that forms strong, adds. “By comparison, making a that they contain unpaired elec- at Louisiana State University in hollow tubes. The scientists, led 20-gallon hydrogen fuel tank that trons, so they try to pair these Baton Rouge. by Richard P. Wool, professor uses carbon nanotubes could lone electrons by “stealing” elec- Also, persistent free radicals of chemical engineering at the cost $5.5 million; one that uses trons from neighboring atoms are similar to harmful chemicals University of Delaware in New- metal hydrides could cost up to or molecules. These atoms or found in cigarette smoke, so they ark, had been investigating how $30,000.” molecules then become free may act on the body the same the feathers could help improve Hydrogen has long been radicals, and they steal electrons, way cigarette smoke does on the performance of electronic held out as a clean energy alter- as well. This can go on with people who smoke. This could circuits. The feather tubes could native to oil, natural gas, and hundreds or thousands of atoms help explain the long-standing be used to carry electrons faster coal. But it is very difficult to or molecules, similar to a chain medical mystery of why non- along a printed circuit, they store and transport—as a pres- reaction that can seriously dam- smokers develop tobacco-related thought. But they noticed that the surized gas it takes up about 40 age cells containing these atoms diseases, such as lung cancer. feathers were not stiff enough, so times as much space as gasoline; or molecules. Once persistent free radicals they heated them to strengthen as a liquid it needs to be kept at Most of the currently known are inhaled, Dellinger suspects the bonds between the carbon extremely low temperatures. free radicals exist for less than that they are absorbed into the atoms in the keratin. The end Wool estimates that it 1 second, so they don’t cause lungs and other tissues where result was stronger and more would take a 75-gallon damage for too long. In contrast, they contribute to the damage to porous feathers. tank to go 300 miles in the newly detected pollutants, cells and DNA. Then, Wool a car using carbonized called persistent free radicals, Dellinger stresses that and colleagues real- chicken feather fibers form on fine particles emitted additional research is necessary ized that the spongy to store hydrogen. He by smokestacks, automotive before scientists can link airborne structures of these says his team is working exhaust pipes, and household persistent free radicals to medical carbonized feathers could to improve that range. chimneys, and can linger in the conditions such as lung cancer. all ph o t s f ro m ist c k absorb as much or perhaps —Doug Dollemore air and travel great distances. —Doug Dollemore

4 Chemmatters, DECEMBER 2009 www.acs.org/chemmatters Hollywood’s

How Did They Do That? By Diana Lutz

joe viskocil

Special effects in movies are not all done with computers. Fake snow, articial skin , and big explosions: They can look like the real thing!

hese days, many special effects are have tried an astounding variety of substitutes done with computers. The fire-spewing Fake snow over the years,” Rickitt says. In the 1930s, Balrog that the wizard Gandalf fights One of the paradoxes of fake snow is that one popular recipe was a mixture of shavings in The Lord of the Rings, the Watcher it is better than the real thing. According to of a soft, white mineral called gypsum and inT the Water, Gollum and the Orc armies at Richard Rickitt, author of Special Effects: The bleached cornflakes. the Battle of Helms Deep are all computer- History and Technique, once snow is tram- Snow Business, whose headquarters is generated. But computer-generated effects pled, it can’t be restored, so snow shots can located in a 17th-century water mill in the have limitations and many films still mix be repeated just once or twice, after which a English countryside, makes more than 170 old-fashioned physical effects with the trendy movie crew needs to move to a new location. types of snow. Depending upon the special computer-generated ones. Darcey Crownshaw, founder and managing effect that a movie director wants, the area Physical effects are usually based upon director of Snow Business, one of the leading that must be covered, the length of the shoot, one simple idea: A material or event is sub- suppliers of movie snow, says that real snow and the budget, snow can be made with differ- stituted for another, usually one that is less is unpleasantly cold and wet. His company ent types of materials, including paper, rice or messy, expensive, or dangerous than the real sometimes covers real snow with “warm potato starch, plastics, foam, and Epsom salts thing. Snow that won’t melt might be made artificial snow that actors can snuggle into like (magnesium sulfate). out of paper and creature skin that sags like being in a down quilt,” he says. In all these cases, the final product must real skin out of latex. Small blasts might But snow is also one of the hardest of all look like snow and, if necessary, must drift, substitute for full-scale explosions. But the natural substances to fake. “Movie makers clump, and melt like snow. This is sometimes basic fiddle, or cheat, is only part of the tricky and not always done success- story. The illusion is helped by tricks of fully. In one recent movie, Crownshaw the trade, often ones known only to prac- noticed snow with “edges,” which was titioners, and it is this unique knowledge actually cheap cotton wadding that was that gives physical effects their sometimes laid down “straight off the roll;” and, in astonishing realism. another movie, a car was sliding through Special effects experts use a wide “wet snow” that clearly looked like deter- range of chemicals. Snow blanketing the gent suds. “Bad snow”—as Crownshaw ground might be made of paper or wood describes it—calls attention to itself, pulp, and falling snow from ash or foam. distracting the viewer from the story the Makeup experts combine either liquid movie is telling. latex or silicone with other chemicals to But looks aren’t everything. Movie

create a patch of skin that is either thick S n o w Bu siness snow, particularly products used on loca- and leathery or soft and wrinkly. To make Snow technicians use dry foam for this falling tion, must be environmentally friendly. snow effect that will be part of a commercial for Many of Crownshaw’s snows are made explosions or fires, they use miniature mod- Waitrose, a supermarket company in the United els, which they blow up or burn. Kingdom. of recycled materials, and the company is

chemmatters, DECEMBER 2009 5 istock careful to use “self-clearing products” in sen- The sodium polyacrylate polymer is actu- Artificial skin sitive outdoor locations, such as a cellulose ally a combination of two polyacrylate poly- The main problem with making artificial powder that can be hosed down easily or a mers linked together like the rails of a railroad skin is that we are intimately familiar with how foam that evaporates within a few hours. track (Fig. 1). Hanging off these “rails” are real skin wrinkles and moves, along with its Crownshaw’s signature product is paper carboxyl groups (-COOH) in which the hydro- translucency and flaws. Anything that is not snow. But there is more to it than you might gen atoms are replaced with sodium atoms quite right about artificial skin—such as a vis- think. If you try to make snow by cutting up (-COONa). When the polymer comes into con- ible blend line at its edge—immediately tips paper, you get confetti. Because the paper tact with water, the sodium detaches, creating us off and destroys the illusion. “flakes” have straight edges, they don’t fall two ions, carboxyl (COO–)—still attached to High-quality skins and prosthetics—which right and, once on the ground, blow about like the chain—and a free sodium ion (Na+). can be anything from fake jowls to pointy dry leaves. Snow Business’s paper snow is ears—are custom-fitted to the actor who torn rather than cut, so the edges are ragged. will wear them. The first step is to make an The torn edges make the snow flakes tumble – exact copy of the actor’s face or body part, as they fall, and, once on the ground, clump COO + and drift like real snow. Na knb efx

– + COO Na – COO– Na+ COO Na+

COOH COOH

COOH

Figure 1. When sodium polyacrylate is in contact with water, it unravels, releasing sodium ions (Na+). all sn o w ph t s b y S n Bu siness

Two mold makers from KNB EFX fill a silicone mold with fiberglass to make a life cast for an actor. Wrinkled skin or bite marks will be sculpted From the film The Day After Tomorrow (2004), on this cast later. this image shows frozen arctic effects.

called a life cast. Then, the jowls or ears are Taken on the set of The Chronicles of Narnia, The sculpted in clay on the life cast. The clay parts Lion, the Witch, and the Wardrobe (2005), this shot shows winter effects created by the company are duplicated in a flesh-like material, such Artificial snow used on movie sets. Snow Business. as whipped latex, that is then glued onto the actor to transform his or her appearance. The carboxyl ions repel one another, wid- Depending upon how the special effects Paper snow is made in huge machines ening the polymer coil. Water moves into the artist wants the prosthetic to look and move, called hammer mills—literally hammers polymer from the outside to dilute the free it can be made of whipped latex, gelatin, or attached to a rotating shaft—that expel the sodium ions. Once the water is inside the silicone. The Chronicles of Narnia, a series of paper through fine screens, shredding it rather polymer, it attaches to the chain by hydrogen fantasy movies about Narnia, a place where than cutting it. “On a typical run, we make 20 bonding, where the hydrogen atoms in water animals talk, magic is common, and good bat- tons of snow, and we make about 500 tons of are attracted to the oxygen atom in the car- tles evil, provides examples of special-effects snow every year,” Crownshaw says. boxylate ions. The polymer swells, but the work with all three materials. Another Snow Business product is a poly- links between the two chains prevent it from The makeup for the films was done by KNB mer similar to the one found in disposable dissolving; instead, it forms a stiff gel. EFX, a special effects studio in Hollywood, diapers. A polymer is a large molecule made If you mix diaper granules with water, Calif., famous for its work on horror and sci- up of repeating small molecules known as what you get looks more like ice than snow, ence-fiction movies. The studio won the 2006 monomers. The granules in a diaper are poly- Crownshaw says. So his team developed a Academy Award for makeup in the first Chron- mers called sodium polyacrylate that readily polymer that swells even more, picking up icles of Narnia movie, which included nearly absorb water. Sodium polyacrylate is made of 4,000 times its weight in water rather than every mythological creature ever invented. repeating units of the monomer the 800 times, which is more typical of diaper Howard Berger—the “B” in KNB—says that [CH2-CH(COONa)]. granules. the studio relied heavily on latex for The Lion,

6 Chemmatters, DECEMBER 2009 www.acs.org/chemmatters the Witch, and the Wardrobe (the first install- molecules cannot move independently any- that hardens the silicone by linking the sili- ment in the series), then shifted to gelatin for more, and the latex goes from liquid to solid. cone polymer molecules together.” Prince Caspian (the second installment) and Latex is an ideal material for artificial skin The catalysts speed up the curing of is planning to rely mainly on silicone for the because it has a fine enough structure to silicone by quickly building bridges between third installment, The Voyage of the Dawn reproduce frown lines and wrinkles, and is silicone molecules. Transition metals such Treader. pliable enough to pick up movements of the as platinum and tin tend to be good catalysts The basic ingredient in latex foam is liquid facial muscles. But its color on film depends because they readily accept and release elec- latex, the milky white sap of the rubber tree upon the lighting conditions on set, a compli- trons, which are then available to participate in that is a dispersion of long-chain polymers cation that led Berger and his team to switch chemical reactions. in an aqueous medium. A foaming agent and to silicone for the upcoming movie, The Voy- For example, if the polysilicone has vinyl a curing agent are mixed into the latex. The age of the Dawn Treader. groups, then a small molecule with at least foaming agent is essentially a soap that two silicon-hydrogen (Si-H) groups is added helps the latex form bubbles, and the curing and the platinum catalyst catalyzes the addi- agent is a mix of chemicals that links the tion of the silicon-hydrogen groups across the polymer chains in the latex. When heated, carbon-carbon double bonds (CH = CH2) the curing agent transforms the liquid latex (Fig. 2). into a flexible solid. joe viskocil k nb efx After all of the ingredients are added, the syrupy latex is tipped into a mixer and whipped into a foam. The amount of time spent whipping the foam greatly affects its consistency, Rickitt says.

An employee of KNB EFX prepares molds that will be filled with silicone. Once the silicone sets, it is peeled from the molds and glued to an actor’s face.

Silicone is a polymer that has a

ist o c k By igniting black powder in the presence of gaso- silicon-oxygen backbone (…-Si-O-Si- line, special effects artist Joe Viskocil makes it Special effects are used to create a virus seem like a fireball is engulfing a house. appearance on hands. O-Si-O-…) with organic side groups—such as methyl [-CH3], ethyl [-C2H5], and vinyl Small bubbles produce dense and heavy [−CH=CH2]—attached to the silicon atoms. Explosives and fires foam, while large bubbles create light and “Silicone comes in the form of a greasy When it comes to explosions, flames, or flexible foam. A heavy foam might be used cream like soft petroleum jelly,” Rickitt says. other similar effects used in the entertainment for a large creature, such as a Minotaur—a “Unlike foam latex, you don’t bake silicone to industry—also called pyrotechnic special mythical monster with the head of a bull and solidify it. Instead, you use a chemical catalyst effects—the problem is to create an illusion of the body of a man—whose skin is thick and towering fires and shattering explosions leathery. Light foam would be used to by the safest possible means. One of create a facial appliance or a skin that R O R O the best ways to do this is to blow up a looks soft and wrinkly. miniature building or truck rather than a O Si CH = CH2 + H Si R O Si CH2 CH2 Si R Once the latex is whipped, a gell- full-sized one. R O R O ing agent is added to the mix, which Special effects expert Joe Viskocil, RRSi R Si R clears the soap from the latex before who has spent nearly 40 years blowing [Pt] the foam is cured. The latex is injected O O up miniatures, is not a fan of big explo- into a mold, which is then left to sit for RRSi R Si R sions. Sometimes, he says, directors 15 minutes so that the gelling agent R O R O who are trying to outdo one another ask can set the foam, and then the mold is him for bigger, more dramatic explo- O Si CH = CH2 + H Si R O Si CH2 CH2 Si R baked in an oven for 1–2 hours to turn R O R O sions. He says, “I have two words for the gel into a sponge. you: Twilight Zone.” During filming in The oven’s heat activates the curing Polymer Crosslinker 1983, a big pyrotechnic effect caused a istock agent, which allows the latex molecules Figure 2. Curing of silicone by attaching silicon- low-flying helicopter to spin out of con- to bind with each other. As a result, the latex hydrogen (Si-H) groups. trol and crash, killing an actor and two child

chemmatters, DECEMBER 2009 7 actors. “No movie is worth a life,” Viskocil downward through the building, which then effects. So, a lot of the explosions and other istock says. explodes. The White House in the movie was effects look to me like cartoons.” After a One of his best known special effects is a plaster model 6 feet high by 12 feet wide. moment, he adds, “The old movies had heart, the explosion of the Death Star in Star Wars “Many movie miniatures are plaster, because and the computer-generated ones are sterile. Episode IV: A New Hope. Producer and plaster shatters into nice chunks that are That’s the way I see it, at least. There is no director George Lucas planned to animate believable as masonry or concrete,” Viskocil magic to it any more.” the explosion; in fact, the cartoons for the says. Might he be right? Viskocil makes this animation had already been drawn. “It looked Viskocil emphasizes that he has licenses observation about his craft, “Commercials cool, very colorful, very weird, but still like an to work with and transport explosive materi- on TV are now so saturated with color they animation,” Viskocil says. So, he decided that als; that he prepares all special effects a physical effect would work better. But what carefully, conducting many tests and would an explosion in space look like? checks; that he has a crew of people who watch his back; and that he calls Richard Rickitt off shots if anything seems even slightly amiss. He would be dev- astated, he said, if anyone were to be injured trying to imitate an effect he had described. Richa rd Ric k itt Joe Viskocil (extreme right) prepares a miniature version of the White House for destruction in Independence Day (1996).

look completely fake. The grass is unnatu- rally green and the sky artificially blue. The Joe Viskocil prepares a scene from the movie producers just take crayons out, in essence, True Lies (1994) in which a bridge explodes. The bridge and the truck were actually miniatures, and color everything as brightly as possible.” and the explosives were set off by the truck as Once Viskocil points this out, you begin to it crossed the 40-feet long bridge. The resulting understand—at least a little—what he means explosion is shown on the cover of the magazine. by heart.

He reasoned that since there is no air and no gravity in space, the explosion should Selected references be perfectly spherical and not lopsided or Richa rd Ric k itt Rickitt, R. Special Effects: The History and Joe Viskocil’s Death Star explosion for Star Wars Technique. There are two editions of this book. squashed. To get a perfectly symmetric effect, (1977). The camera is on the floor, looking up at One published by Virgin Books in 2000 and the he put the camera on the ground and filmed the explosion. second, which is considerably revised, by Arum straight up. Press, 2006. Recipe for fake snow: http://chemistry.about.com/ A cardboard container of black powder od/chemistryhowtoguide/ht/fakesnow.htm mixed with titanium shavings was suspended The end of film? [August 2009] from the studio’s ceiling. Black powder is a Viskocil and other special effects experts YouTube videos showing the process of making prosthetics: mixture of sulfur, potassium nitrate (KNO3), say that they are living on borrowed time. and charcoal—a black substance made “We’re dinosaurs,” Viskocil says. “The com- The Making of Abraham (Part 1): http:// youtube.com/watch?v=rNtuE6NF2Eg [August mostly of carbon, along with other chemicals, puter has taken over the movie business. 2009] and resulting from the heating of wood. When Eventually there won’t be any film, which is an The Making of Abraham (Part 2): http://you- the black powder ignited, sparks and debris incredibly sad state of affairs for an art form tube.com/watch?v=YeNYDVwiW20&feature=rel ated [August 2009] were propelled toward the camera as if travel- that is now more than 100 years old.” Pan’s Labyrinth: http://youtube.com/watch?v=c- ling outward in the vacuum of space. The Perhaps not surprisingly, Viskocil says sSsRaoohc&feature=related [August 2009] technique was so successful that it has been he is not impressed by computer-generated NOVA: Fireworks and Black Powder: http://www. copied many times since then. effects. “The first Star Wars was all done pbs.org/wgbh/nova/fireworks In 1997, Viskocil won the Academy Award with models with real explosions, and none Pyrotechnics and Fire (under “Effect Type”), Artem Visuals Web site: http://www.artem.com/ for the special effects in Independence Day, of those were color corrected or computer a science-fiction film about an alien invasion enhanced,” Viskocil says. “What you saw, of Earth. When the death ray from the alien is what we actually shot. The last three Star Diana Lutz is a science writer in Madison, Wis. spaceship hits the White House, a fireball rips Wars used a minimum amount of special This is her first article in ChemMatters.

8 Chemmatters, DECEMBER 2009 www.acs.org/chemmatters kenneth libbrecht Snow crystal photographs by Kenneth Libbrecht and humidity. dependsupon temperature that theshapeofasnowcrystal Figure 1.Nakaya’s morphology diagramshows snowcrystal S two alike. more than 5,000 snowflakes, and never found flakes before they melted. He took pictures of perfected a process for photographing snow when a photographer named Wilson Bentley for more than a century. studying how these crystals form and grow and snowflake enthusiasts, who have been have fascinated scientists, photographers, branched snow stars. These natural wonders larger and formed complex branches. tals were small. At high humidity, they grew grew tall and thin. At low humidity, the crys tals grew short and wide, while at –5 example, at a temperature of –2 humidity affected how the crystals grew. For tals. He showed that the temperature and Nakaya grew the first man-made snow crys Then, in 1930, Snow crystal research began in 1885 flat plates, long thin columns, and variety of shapes, including wide now crystals come in an incredible Crystals from theClouds J apanese physicist ° C, the crys ° U C, they kichiro - - - - form andgrowform How snowcrystals structure of snow crystals results from two sides and six equal angles. form hexagons—plane figures with six equal water molecules always arrange themselves to matter what shape the crystal comes in, the molecules of water vapor bind to it. But no the crystal grows in different directions when crystallizes onto a small particle of dust. Then, they come in so many shapes. crystals are made of, how they grow, and why made interesting discoveries about what snow and humidity. tals based upon the surrounding temperature possible to predict the shapes of snow crys gram shown in Fig. 1. For the first time, it was Scientists have shown that the hexagonal A snow crystal forms when liquid water For the past half-century, scientists have Nakaya summarized his findings in the dia poles is called a polar molecule. positive. A molecule that has two tive and the hydrogen end is partially the water molecule is partially nega charge. As a result, the oxygen end of atoms are left with a slightly positive from the hydrogen atoms. So, these shares with the hydrogen atoms away partially pulls the electrons that it This is because the oxygen atom somewhat positive charge (Fig. 2a). two hydrogen atoms each have a somewhat negative charge and its means that its oxygen atom has a First, water is a polar molecule, which properties of the water molecule. By AndreaHazard - - - with sixprismfacetsandtwobasalfacets. isahexagonalprism, shape ofasnowcrystal andc.thebasic structure ofasnowcrystal; Figure 2.a.Water molecule;b.molecular are called basal facets. prism facets, and the top and bottom surfaces called facets. The side surfaces are called (Fig. 2c). The prism has smooth, flat surfaces atop one another, forming a hexagonal prism These hexagons can grow in width and stack that are connected to one another (Fig. 2b). rally form a series of hexagon-like structures these molecules bind to each other, they natu fact that water molecules are polar, when of 104.5 oxygen and hydrogen together form an angle molecule is that the bonds that connect the relatively quickly. to these rough surfaces, which thus grow Water molecules from the air readily attach with dangling, unbonded water molecules. The other interesting property of a water An ice crystal contains rough surfaces, ° chemmatters , DECEMBER 20099 . Because of this geometry and the U nlike these rough surfaces, a.

an rd drea haza

b. kenneth libbrecht

c. Andrea Hazard - the facet planes tend to Plates versus growing snow crystal drifts through the atmo- be smoother, with fewer sphere, it encounters many different condi- dangling bonds. Water columns tions of temperature and humidity,” Libbrecht molecules cannot so eas- As the temperature decreases from 0 °C to says. “A crystal that starts out in conditions ily attach to these smooth subfreezing temperatures, the crystal shape that favor branching may drift into conditions surfaces, so the facet sur- switches back and forth between plates and that favor plate formation on the tips of the faces advance more slowly. After columns. Kenneth Libbrecht, a physicist at the already formed branches, and then new condi- all the rough surfaces have grown out, what California Institute of Technology in Pasadena, tions may arise that lead to even more shape remains are the slow-moving facet surfaces. who has been studying snow crystals for the diversity. In short, the complex atmospheric past 12 years, believes the chemistry at the conditions can give snow crystals a Branched snow stars crystal’s surface may explain this seemingly infinite variety of odd temperature dependence. shapes.” Environmental conditions can sometimes Snow crystals are coated cause snow crystals to deviate from a basic with a thin layer of water A new look hexagonal shape and form branched snow molecules called a “quasi- stars instead. A branched snow star forms liquid” layer, because it is at snow- when a growing snow crystal depletes water neither solid nor liquid, flakes vapor from the surrounding air. The crystal but something in between. If you are lucky—or can no longer grow until more water mol- Libbrecht believes that the unlucky—enough to ecules float into its vicinity. snow crystal’s temperature Because the edges of the crystal stick out live in a snowy region, go a bit more than the faces, there is a slightly out into nature’s laboratory,

m catch snow crystals on your greater chance that a drifting water molecule ike ciesielski will crystallize onto an edge than a face, caus- gloves and think about atmospheric ing the edges to grow faster (Fig. 3). As they conditions that formed them! grow, the branches keep a hexagonal symme- Also, if you want to keep a record of a try and faceted surfaces. snowflake, you can make a snow fossil. Let But the most stable crystal structure a snowflake fall on a cold glass slide and is a simple hexagon. So, after a cer- cover it with superglue. When the glue dries tain period of time and with enough and the flake melts, you have a snow water vapor, the shape of these branched fossil. Visit http://snowcrystals.com ph o t ogr aphs b y Kenneth L ibb r echt stal S n o w c ry snow crystals reverts to a simple hexagonal for more ice crystal experiments you prism—the dominant crystal structure in can try at home, even if you don’t live in snow banks. the Great Lakes region or the northeastern kenneth libbrecht part of the United States. This Web site also includes photo galleries of snowflakes.

dependence is due to the pres- ence of impurity molecules on the crystal’s surface that interact Selected references with the quasi-liquid layer. “The Christner, B. C.; Morris, C. E.; Foreman, C. M.; k enneth libb r echt ice surface is likely covered with Cai, R., Sands, D. C. Ubiquity of Biological Ice Figure 3. Rough surfaces (right and left) have more dangling impurity molecules, even in very Nucleators in Snowfall. Science 2008, 319, p water molecules than smooth surfaces (middle area), so rough 1214. surfaces more readily attract water molecules. clean air,” Libbrecht says. “Our Cooray, V. The Lightning Flash; Institute of studies have shown that the Engineering and Technology: Edison, NJ, Branching only occurs under conditions of interaction of these impurity molecules with 2003; pp 27–30. high humidity, as can be seen in Nakaya’s the quasi-crystal layer affects how Libbrecht, K. G. The Snowflake: Winter’s Secret Beauty; Voyageur Press: Stillwater, MN, 2003. diagram (Fig. 1). This is because high the crystal grows. But how this Libbrecht, K. G. The Physics of Snow Crystals. humidity favors rapid growth that happens is still being investi- Reports on Progress in Physics 2005, 68, pp depletes water vapor from the gated.” 855-895. crystal’s surroundings. At very Not only temperature, Rosenberg, R. Why Is Ice Slippery? Physics Today, Dec 2005, pp 50–55. high humidity, branches can but other environmen- form on branches, resulting in tal conditions—such as complex crystals. humidity—give rise to Andrea Hazard is a writer and illustrator who the variety and complexity lives in Danby, N.Y. This is her first article in of snowflake shapes. “As a ChemMatters.

10 Chemmatters, DECEMBER 2009 www.acs.org/chemmatters SPACE FOOD By Kathy De Antonis

ating in space goes as far back as John Glenn’s first orbit around the Earth in 1962. Given the magnitude of his accomplishment, not much attention was paid to the food that he ate, a paste that he squeezed into his mouth from what looked like a toothpaste tube. It was nutritious for sure, but not very appetizing. nasa

The National Aeronautics and Space Administration (NASA) has much iron in microgravity. In the body, iron is found in the blood. In come a long way in its effort to provide a variety of appetizing foods for microgravity, the body does not need as much blood, so it reduces its astronauts in space. Based upon extensive studies by food scientists the total volume of blood by destroying red blood cells as soon as working closely with astronauts, different types of foods are now pre- they are produced, leading to about 15% less blood in the body than pared and packaged to make them last longer and taste better and to on Earth. The iron that is bound to these red blood cells is released make them easier to transport in space. and stored elsewhere in the body. An excess of iron in the body Vickie Kloeris, a NASA food scientist, leads a team of food scientists, can be harmful, so dietary intake of iron is reduced in space to help engineers, dietitians, and technicians who work at the Johnson Space reduce the amount of extra iron in the body. Center in Houston, Texas, on testing and making many different foods Likewise, astronauts are prone to bone loss during extended mis- for astronauts. sions in space because the body senses that the skeleton is not One of the main challenges for NASA food scientists is to make these required for support in flight as it is on Earth. In the low gravity of the foods tasty, so they try different recipes and keep the ones that work space shuttle and ISS, not as much bone mass is needed to support best. It is a lot of work, but you need to keep the astro- the body as is needed on Earth. When people eat food containing cal- nauts happy, especially if they have to stay in space cium, a critical nutrient for healthy bones, calcium is absorbed into the for months or years on end! bloodstream, where it is delivered to the bones. But because the body is actively trying to reduce the amount of bone, the rate of calcium Meeting astronauts’ absorption from the diet is lower in space than on Earth. Research is ongoing at NASA to learn more about how nutrients nutritional needs are processed differently by the body in space and on Earth. At the Johnson Space Center, the Space Food Months prior to liftoff, each astronaut spends some time in the Systems Laboratory develops food used on the Space Food Systems Lab, sampling an assortment of space foods. space shuttle and the International Space Station Shuttle astronauts select a menu for every meal that they will eat while (ISS) and is working on ways to feed astronauts on in space, and ISS astronauts select food items that complement their longer trips in the future. basic menu. An interesting finding made by NASA scien- tists is that some nutrients in the body behave Eating in space is no differently in space than they do on Earth. picnic, but it would ist o c k For example, astronauts don’t need as be cool to have a picnic on the moon!

chemmatters, DECEMBER 2009 11 What is space Salt and pepper are also modified for use Once he worked past the preparation, Daley food like? in space. They cannot be shaken over food found that most of the foods did not meet his because the particles will float away. So, salt is standards. “Space food isn’t restaurant cook- The Space Food Systems Lab faces many dissolved in water and pepper is mixed with oil. ing; it’s not even takeout. If anything, it’s more constraints when producing space food. Food along the lines of a frozen dinner—but you get must be lightweight, compact, and require Does it taste good? bigger portions from the frozen-food aisle.” minimal preparation. Also, the food must be That said, he was satisfied by some things. well preserved, so it does not spoil in space in Bill Daley, a food critic at The Chicago “I particularly enjoyed the dried peaches, the absence of refrigerators or freezers. Even Tribune, ventured to answer that question. because of their intense flavor and a satisfy- food consistency is considered. Crumbly He sampled and critiqued a dozen space food ing, chewy texture,” he says. foods don’t work well in space because rations that were small particles will float in near-zero delivered to him gravity and potentially get into the as they would Freeze-drying food workings of the spacecraft. be delivered Freeze-drying is probably one of the most To take all these restrictions to astronauts fascinating ways of preparing space food. This into account, scientists at the in space. He process not only removes as much water as Space Food Systems Lab have quickly realized possible from a given food but also preserves come up with different catego- the challenges it for as long as possible. ries of food. For example, soups, that astro- Food spoils when microorganisms, such casseroles, and scrambled eggs nasa nauts face as bacteria, feed on the matter and decom- are “freeze-dried.” After they are in eating a pose it. Bacteria may release chemicals that prepared, water is almost entirely simple meal. cause disease or may just release chemicals removed prior to packaging, making these The serving-size portions were that make food taste bad. Bacteria need water foods lighter to carry and more compact. delivered in plastic pouches, each labeled to survive, so if you remove water from food, Once astronauts are in space, they add water with preparation instructions, such as Critical point back to these foods before eating them. how much water to add or how long 218 atm Some foods, such as to warm it. He was unprepared for the awkwardness of rehydrating freeze- tuna, are “thermostabi- 1 atm lized,” that is, they are dried foods by injecting water into the heat-processed after pouches with a 60-milliliter syringe Water (liquid) they are packaged. Other and reheating thermostabilized food Pressure Ice (solid) foods, such as some pouches in a warm water bath. These meats, are irradiated are cooking techniques that chefs don’t 0.006 atm after they are cooked and frequently use here on Earth. Triple point Water vapor(gas)

packaged. Thermostabili- Daley was surprised to find he anth o n y fe r nan d e z 0.01 °C 100 °C 374 °C zation and irradiation are needed a pair of scissors among his Temperature ways of sterilizing food so utensils. He found it to be a critical Figure 1. Water can take the form of solid, liquid, that it can be stored in the tool—and astronauts use scissors during or gas, depending upon different values nasa absence of refrigerators every meal to open their food pouches. Fas- of temperature and pressure. and freezers. Unlike freeze-dried food, these tened to each pouch is a Velcro disk, which two types of food do not require the addition is of no use here on Earth, but in space, it is it won’t spoil. Freeze-dried foods can be of water and are edible as is. critical for fastening the pouches to a tray so stored for years and then be restored with they don’t float. just a little water. Freeze-drying is different from dehydra- tion, which involves heating food in dry air Try it! until the moisture is gone. But dehydration You may be able to buy usually doesn’t remove more than 90% of the space food at your local water, so bacteria can still grow. Freeze-drying science museum. more successfully removes a much higher percentage of the water. Typically, the foods have less than 3% of the remaining water, and the food’s composition remains otherwise unchanged. Freeze-drying relies on a natural process, called sublimation—the conversion of frozen water present in foods directly to gaseous water. Depending upon the surrounding mi k e ciesiels i

12 Chemmatters, DECEMBER 2009 www.acs.org/chemmatters temperature and pressure, water can exist as a solid, a liquid, or a gas. By varying the temperature and pressure, it is possible to see water go from one of these forms to another. The temperatures at which water goes from solid to liquid (melting), liquid to gas (boil- ing), and solid to gas (sublimation) vary with nasa the surrounding pressure (Fig. 1). There is one value of temperature and pressure (0.006 Space food of the atmosphere of pressure and 0.01 oC)—called the triple point (Fig. 1)—for which water coex- future ists at equilibrium as a solid, a liquid, and a nasa In the future, NASA is looking to send gas. At any pressure below 0.006 atmosphere, astronauts to outposts on the moon and Mars. liquid water cannot exist and ice is converted into electricity. In a battery, the chemical reac- Although the target for liftoff for the moon directly to water vapor—that is, it sublimes— tants are limited to what is contained inside; mission is not until 2020, efforts are already when heated. so, once they are consumed, the battery runs under way at the Space Food Systems Lab. The process of freeze-drying takes advan- out of power. In contrast, a fuel cell can con- Scientists in the Advanced Food Technology tage of this property, as follows: First, the tinue working as long as the chemical reac- group, led by NASA food scientist Michele temperature is reduced below 0 oC until all tants are added to the cell from the outside. A Perchonok, are developing foods that are water present in a given food is frozen solid. byproduct of the chemical reactions occurring “nutritious, good tasting, and provide variety Then, pressure is reduced below 0.006 atmo- in a fuel cell is water vapor, which can be con- for a 3-year mission.” sphere, and the food is slowly warmed to a densed into liquid water and stored. The biggest challenge for these future temperature above the freezing point. With In a fuel cell that is used on the space missions is a food’s shelf life. “For an initial time, the water sublimes and is drawn away shuttle, electricity is produced via two reac- trip to Mars, you will need products that by vacuum. Over many hours—sometimes tions that occur simultaneously near two con- have a 5-year shelf life,” Kloeris says. The even days— 97% or more of the water is ducting materials, called anode and cathode only foods that have currently shown such removed, leaving the freeze-dried food. (Fig. 2). Hydrogen gas (H2) is delivered to the a long shelf life are a few thermostabilized anode and oxygen gas (O2) is delivered to the foods, which is not enough to provide a bal- Rehydrating freeze- cathode. Near the anode, hydrogen reacts with anced diet, Kloeris says. hydroxide ions (coming from the cathode) to Perchonok and her team are looking at dried food produce water and electrons: ways to improve packaging materials that will Aboard the space shuttle, water is pro- provide a better barrier to water and oxygen— – – duced by battery-like devices, called fuel H2 + 2 OH ➞ 2 H2O + 2 e which can cause food to spoil. This way, the cells, which also provide electricity. Each shelf life for many current food items can space shuttle is powered by three fuel cells Near the cathode, oxygen reacts with water be extended. Another area of research is to that are tucked beneath the cargo bay. Each and the electrons to produce hydroxide ions develop ways to transport some foods—such one weighs about 225 pounds and is 45 (OH–): as wheat berries and soybeans—in bulk to inches long, 15 inches wide, and about 14 reduce the amount of packaging materials – – inches high. O2 + 2H2O + 4e ➞ 4 OH used and to minimize waste. Like a standard battery, a fuel cell converts “A 1,000-day mission to Mars for a crew energy produced through chemical reactions The hydroxide ions then move to the of six will need about 10,000 kilograms if we anode, and the cycle starts again. The elec- went with our packaged food system,” Per- Electrical current trons that are produced at the anode are chonok says. “If we can save on that by grow- e- e- routed into an electrical circuit that powers the ing some items, by bringing some items up in Hydrogen in Oxygen in shuttle. bulk, it will be a lot easier.” H O 2 e- 2 The net result of the two reactions, called e- oxidation (at the anode) and reduction (at the Selected references Freeze drying: http://www.aboluteastronomy.com/ e- e- cathode), is water: topics/Freeze_drying [July 2009] OH– e- – – NASA: Fuel Cell Power Plants: e- Anode 2[H2 + 2 OH ➞ 2 H2O + 2 e ] H2O – – http://spaceflight.nasa.gov/shuttle/reference/ e- Cathode O2 + 2H2O + 4e ➞ 4 OH shutref/orbiter/eps/pwrplants.html [July 2009] Water and e- Net Reaction 2H + O ➞ 2 H O heat out e- 2 2 2 Space Travel and Nutrition: http://www.faqs.org/ e- nutrition/Smi-Z/Space-Travel-and-Nutrition.

anth o n y fe r nan d e z html [July 2009] Taken together, the fuel cells can produce Anode Cathode Electrolyte up to 25 pounds of water per hour, which is more than enough to meet the astronauts’ Kathy De Antonis is a science writer who lives Figure 2. Schematic representation of what in Old Saybrook, Conn. This is her first article in happens in fuel cells used on the space shuttle. needs. ChemMatters.

chemmatters, DECEMBER 2009 13 ale university

beÌnecke rare book and manu scy ript library,

By Linda Zajac

quare sails billowed in the mist, discovery, that map is now locked safely in as a great Viking ship carved its a vault at Yale University’s Beinecke Library, way past icebergs and ocean New Haven, Conn. swells. In the open wooden boat, theS Vikings ventured farther across danger- One man’s treasure ous uncharted waters, risking their lives to discover what lay beyond the setting sun. On changes history the horizon, a new land of barren rock and The map first surfaced in Geneva, Swit- shutterstock glaciers rose from the sea. zerland, when Laurence Witten, an antique The Vikings reached shore at the north- book dealer from New Haven, browsed ern tip of Newfoundland, now part of Canada. through soiled and water-stained books that On shore, they were chilled by an ocean an Italian book dealer, named Enzo Ferrajoli, breeze that swept through tall thick grasses had offered him. on knobby green hilltops. On this lush green seven expeditions to unearth the ruins of a Witten spent hours examining the Tartar cove by the bay, the Vikings made their home. Viking settlement at L’Anse aux Meadows in Relation, an account by Italian traveler and But over time, the location of this historic Newfoundland. Archaeologists uncovered Franciscan monk Friar John de Plano Carpini Viking landing was lost. In 1953, Norwe- cooking pits and charcoal kilns, houses, and of his mission to the empire of the Mongols gian explorer Helge Ingstad visited a Viking hearths. Later, scientists and scholars bitterly (or Tartars) in Central Asia from 1245 to 1247. settlement site in Greenland, sparking a debated whether these brave explorers left a Although the slim volume, which contained a burning desire to find a landing site in North map of their voyage. crude map, had been carelessly patched and America. He scoured the northeastern coast of In 1957, a faded world map was dis- rebound with a modern binding, Witten fell Newfoundland, searching for possible sites. covered in Europe. It appeared to be drawn under its spell. Finally, in 1960, he spotted ridges in by the Vikings and cast doubt about whether Other customers interested in purchasing the grass, the remains of an ancient colony. Columbus knew of its existence. If authen- the Tartar Relation had doubts about whether He was unsure whether the site had been tic, it was proof the Vikings were the first to the map belonged with the manuscript. There settled by Eskimos, American Indians, or set sail for the New World. Scrutinized and was no record indicating where the book came Vikings. From 1961 to 1968, Ingstad led disputed for nearly half a century since its from. Worms had chewed through the manu-

14 Chemmatters, DECEMBER 2009 www.acs.org/chemmatters script and map, but the holes didn’t align. the Vinland Map was the only map of America in yellow, then in black. After hundreds of Despite the uncertainty, Witten paid $3,500 for produced prior to the voyage of Columbus. years, the ink in medieval documents leaches the book. Some scholars wondered whether Columbus into the parchment fibers to produce a yellow On thin crisp folded parchment, in fine knew of the map before setting sail. stain. She assumed that the map was drawn Latin script, the map detailed the voyage of first in yellow ink, redrawn with black ink, and the Vikings who sailed from Greenland to A close look at the ink then most of the black ink was chipped away. Vinland, a fertile land with vines. Vinland is In the yellow ink, Teetsov, along with Wal- thought to represent the Baffin Islands, Lab- The authenticity of the manuscripts was not ter McCrone, a chemical microscopist and rador, or Newfoundland, all parts of Canada. questioned, but some scholars and scientists founder of McCrone Associates, expected to had concerns about the map. Greenland was The Vinland Map is the only known map of a find titanium dioxide (TiO2), a brilliant white Viking voyage. In 1957, it was a sensational drawn with striking accuracy. On all other paint pigment that naturally occurs in three find. medieval maps, Greenland is shown as a pen- mineral forms: rutile, brookite, and anatase. The following year, at his home in Con- insula, but on the Vinland Map, it is an island. With a transmission electron microscope, necticut, Witten leafed through the dilapidated In 1967, the ripple-edged map was which uses a beam of electrons instead of binding of another medieval manuscript. The flown to the British Museum for an exhibi- light, they noticed small rounded crystals. Speculum Historiale, a Mirror of History, was tion. While it was there, A. D. Baynes-Cope, a The scientists determined that the crystals like an encyclopedia for the Middle Ages. It scientific officer at the museum, examined it were anatase, which was available only since contained portions of French Dominican Friar under a microscope. Under ultraviolet light, 1917. Based upon the evidence, they came to Vincent of Beauvais’ history of the world from the inks in the manuscripts were black against an unfortunate conclusion. “It was a brilliant creation to the time it was written in the 15th a glowing fluorescent background. This is typ- job of forgery,” McCrone said. century. ical of inks made by crushing larval growths, Witten noticed striking similarities to the or galls, on oak trees to create gallotannic Retesting the ink with Tartar Relation. Both manuscripts were written acid which is used to make medieval iron-gall in two columns of Gothic cursive. He recog- ink. But the ink in the map behaved differ- a blast of protons nized a watermark he had seen in the Tartar ently. “The ink was unlike any other ink we But the debate was far from over. Relation, a bull’s head wearing eyeglasses. had encountered in authentic medieval docu- In 1985, the map and manuscripts were “My heart began to pound,” Witten wrote. ments, and no explanation could be found for tested at the Crocker Nuclear Laboratory at the With a ruler, he carefully measured where this,” Baynes-Cope wrote. University of California, Davis. Using a new worms had chewed through the map and manuscripts. The wormholes in the Tartar Relation were in the same spots as the holes at the end of the Speculum Historiale. When Witten compared the wormholes in the map to those at the front of the Speculum Historiale, he was shocked—they perfectly aligned. wormhole Like a puzzle snapping into place, Witten realized that,

y © c o p yr i g ht 2002 b y l is f ru en it s r at one time, e iv b n ei u ne le the manuscripts ck ya ➞ e r y, gallic acid + ferrous sulfate heptahydrate (FeSO4.7H2O) + H2O iron-gall ink ar ar e r and the map were boo lib k an ript d manusc bound together as one. In the Midlle Ages, iron-gall ink was made by converting gallotannic acid into gallic acid (first chemical He concluded that the Speculum Historiale reaction), and then by combining gallic acid with ferrous sulfate heptahydrate and water (second was sandwiched between the Vinland Map chemical reaction). and the Tartar Relation and that the map was drawn to illustrate a portion of the Speculum In 1972, McCrone Associates, Inc., method, Thomas Cahill, professor emeritus Historiale. In a stroke of good fortune, Witten in Chicago, Ill., analyzed the map using new of physics and atmospheric sciences, and his had stumbled upon the missing manuscript. scientific techniques. With a tiny drop of rub- colleagues retested the ink. They used a tech- Now, he was certain the Viking Map was real. ber cement at the end of a fine-tipped needle, nique, called Proton Induced X-ray Emission He immediately contacted the curator Anna Teetsov, a senior research microscopist (PIXE), in which a massive machine called a at Yale University’s library. Yale assembled from McCrone Associates, delicately plucked cyclotron is used to accelerate charged parti- a team of scholars who painstakingly 29 ink samples from the map and viewed cles called protons. As a beam of high-energy researched the map’s authenticity. In 1965, them under a microscope. Teetsov reasoned protons is fired at a sample—in this case, the Yale stunned the nation by announcing that that the map was “double inked”—drawn first Vinland Map—the protons collide with atoms

chemmatters, DECEMBER 2009 15 in the sample, and X-rays are recorded. X-rays Radiocarbon dating is a method to estimate ning proof that the Vinland Map parchment of the elements in the map appeared as sharp the age of an organic material. The parchment was ancient. peaks and valleys on one graph. is a wafer-thin material made from the skin of Although Cahill’s team found titanium in sheep, goats, or calves. As living organisms Real or fake? several spots on the map, roughly one-third of breathe and eat, they consume carbon from the inked lines that they tested showed no tita- the atmosphere. Most of the carbon con- Despite numerous tests on ink and parch- nium above a minimum detectable limit. They sumed is carbon-12, an abundant isotope of ment, the controversy continues. One undis- concluded that titanium dioxide was present carbon that contains six protons and six neu- puted piece of evidence could be the key to only in trace amounts in the ink and that it trons and does not change over time. Much solving the Viking mystery. For Ingstad, a could not be the basis of the yellow ink. rarer is carbon-14, a radioisotope of carbon critical piece of evidence linking the Vikings With a microscope, Cahill’s that differs from carbon-12 in the number of to the settlement site at L’Anse aux Meadows team closely inspected the neutrons that it contains (eight instead came on the final day of the last expedition. map’s fine faded lines. of six). Kneeling in the ruins of a four-room The thin black When a living organism dies, house and scraping the soil at the edge of a lines were the ratio of carbon-12 to car- cooking pit, archaeologist Sigrid Kaland sud-

drawn bon-14 is the same as in the denly shouted, “I found bronze!” Carefully,

y r

o Kaland brushed away the dirt. She stared in t

a surrounding atmosphere. Over

r o

b disbelief at a corroded pin the length of a a time, carbon-14 decays, that l

l a twist-tie, green and bronze. Clearly, it was a n

o is, it transforms into another i

t

a n Viking pin used to fasten a cloak. “The best

n element, namely nitrogen-14, e v a find of all was in truth the final clue,” wrote h almost k which contains seven neutrons o o r Anne Stine Ingstad, archaeologist and wife exactly over b and seven protons. After about the yellow lines, of Helge Instad. “We practically exploded in an extremely chal- our excitement!” lenging feat. “The McCrone Ingstad’s remarkable discovery of Viking ‘double inking’ hypothesis was ruins left no doubt that the Vikings were the impossible,” Cahill said. “Our work argues first to discover the New World. But did they strongly against the specific McCrone Associ- leave a map of their voyage? Like a ring- ates’ proof that the map is fraudulent,” he headed pin lost among the ruins, the identity wrote in a 1987 paper. of the scribe is a key piece of evidence, buried With hope riding high, Yale locked the map in the past. securely in a vault. “The insurance was raised More than half a century has passed since to millions of dollars,” Cahill revealed. the Vinland Map first surfaced. Scientists and scholars still debate whether the map is authentic or a clever forgery. History has left Dating the parchment ory o nal lab or at v en nati an incredible secret etched in the fine faded

In the 1980s, Garman Harbottle, a retired b rook ha lines of this ancient parchment. senior chemist at the U.S. Department of Garman Harbottle and Jacqueline Olin slice a Energy’s Brookhaven National Laboratory, strip (inset) from the Vinland Map. Selected references Upton, N.Y., and Jacqueline Olin, a retired Ingstad, H., Ingstad, A. S. The Viking Discovery of chemist at the Smithsonian Institution, Wash- 5,730 years, half of the carbon-14 decays into America: The Excavation of a Norse Settlement ington, D.C., urged Yale to pursue radiocarbon nitrogen-14. By comparing the amount of car- in L’Anse Aux Meadows, Newfoundland; dating to determine the age of the parchment. Checkmark Books/Facts on File: New York, NY, bon-14 and carbon-12 in an organic material, 2001. But this technique destroys the sample. scientists can determine a radiocarbon date. Seaver, K. A. Maps, Myths, and Men; Stanford “We wrote two or three proposals to Yale At Beinecke, in 1995, Olin sliced a University Press: Stanford, CA, 2004. University to allow strip from the bottom-right corner. Then, at Dent, J. NOVA: The Viking Deception: The Truth the sampling,” Behind the Vinland Map. Providence Pictures, the University of Arizona, Tucson, the sliver 2005. Harbottle said. “All of parchment was snipped into six pieces. Skelton, R. A., Marston, T. E., Painter, G. O. The were shot down.” Each piece was first soaked to remove con- Vinland Map and the Tartar Relation, Yale When Harbottle taminants and then burned. Using a special University Press: New Haven, CT, 1995. and Olin recruited YouTube Video; Lawrence Berkeley National machine, the carbon dioxide gas that was Laboratory, Berkeley, Calif.: http://www.you- a radiocarbon produced was converted to graphite. tube.com/watch?v=M_jIcDOkTAY expert, Yale finally Finally, a huge machine called an accelera- agreed. ory o nal lab or at v en nati tor mass spectrometer counted all of the car- Linda Zajac is a science writer in Vernon, Conn. bon-12 and carbon-14 atoms in the graphite Her most recent article, “Glowing Proteins with

b rook ha Promising Biological and Medical Applications,” Garman Harbottle examines sample. Radiocarbon dates for the parchment appeared in the December 2008 issue of the Vinland Map. pieces fell between 1411 and 1468— stun- ChemMatters.

16 Chemmatters, DECEMBER 2009 www.acs.org/chemmatters PROFILES IN CHEMISTRY

J. L. Kiappes Silver Medalist in the

2004 International

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By Christen Brownlee ington, D.C. Past winners of the International teacher, going through lots of different AP- ow much chemistry do you know? Chemistry Olympiad were present, along with level chemistry textbooks to learn as much as HOne way to put your knowledge to teachers and mentors who helped them pre- I could to prepare for the test. the test is by competing in the International pare for the competition. Chemistry Olympiad. Since 1968, this contest I talked with J. L. Kiappes, a silver medalist Tell me about the national exam— has challenged high school students to see in the 2004 International Chemistry Olympiad is it really hard? how their chemistry comprehension stacks and now a doctoral candidate at the Scripps It’s a tough test because it covers so much up against the best minds from around the Research Institute in La Jolla, Calif., and the material. The exam lasts 4 ½ hours and con- world. Like the athletic Olympic Games, top University of Oxford in the United Kingdom, to sists of a multiple choice section, an essay finishers in the Chemistry Olympiad win get the real scoop on what it’s like to take part section, and two lab practicals. I immediately bronze, silver, or gold medals. The top 10% in this tough—but rewarding—test of chem- knew the answer to some of the questions, of finishers receive gold medals; the next istry prowess. but there were other questions for which I had 20% receive silver; and the next 30% bronze. absolutely no idea what the answer was. I had The United States has been participating in How did you become involved with the to tell myself: What do I know, what can I find this competition since 1984, so 2009 is the International Chemistry Olympiad? out, what’s reasonable? As a senior, it was my 25th anniversary—or silver anniversary— I’ve been interested in chemistry for a long last year to take the exam, so I really wanted of U.S. participation. This anniversary was time. I remember making a model of an atom to do well. I was totally wiped out when I fin- celebrated at a reception that was part of in sixth grade and being intrigued—I thought: ished the test, but I was glad I had done it. It’s the 238th National Meeting of the American This is what I want to do. In my junior year of one of the few opportunities to see how much Chemical Society on August 16–20 in Wash- high school, I took advanced placement (AP) chemistry you know. chemistry, and the teacher encour- aged all of us to take a scholar- Don’t keep us in suspense— ship exam. When I was looking how did you do? for information online about the A little bit less than a month after I took the exam, I ran across information exam, I got a call from the local ACS chapter about the Chemistry Olympiad. I with exciting news: I had earned a spot at learned that to qualify for the U.S. the Olympiad Study Camp! Only 20 students National Chemistry Olympiad— who take the national exam are selected for the contest that selects students the camp each year to prepare for the interna- for the International Chemistry tional competition. Soon after I learned that I Olympiad—I would need to take would be going to Study Camp, I received an a qualifying exam given by local organic chemistry textbook in the mail from chapters of the American Chemical the camp’s mentors, along with a letter tell- Society (ACS) across the country. ing me to start preparing by reading the first

k i na d ine s z c epans It was too late for me to take the eight chapters. The 2004 U.S. team (from left to right: Eric Brown, Fan Zhang, In June, I flew to the U.S. Air Force Acad- Emily Tsui, and J. L Kiappes) won four silver medals at the exam that year, so I decided to do International Chemistry Olympiad in Kiel, Germany. it my senior year. I worked with my emy in Colorado Springs, Colo., where Study

chemmatters, DECEMBER 2009 17 competition—which was How has participating in the Chemistry in Kiel, a coastal city in Olympiad changed your life? northern Germany, that I went to Rice University in Houston, Texas, year—I tried to study a few weeks after I went to the International up on everything I didn’t Chemistry Olympiad. Participating in this know at Study Camp. competition prepared me for what some call In mid-July, the team the culture shock of having to learn so much met in Washington, when you are in college. It also gave me a D.C., to travel to Ger- leg up on my chemistry classes through many together. When my junior year of college, since I had been we arrived in Germany, exposed to so much material while preparing teams from 60 other for the Olympiad exams. g, chemical & en g ineerin news lin d a wan J. L. Kiappes (right) helps students at the Study Camp in Colorado in 2008. countries were all arriv- Also, the National Chemistry Olympiad ing around the same allowed me to meet and work with exceptional time. We all stayed mentors and other students. The relationships Camp takes place. For 2 weeks, I and the other together at a hostel—a lodging place with dor- that I built during my summer as a student at camp attendees crammed as much chemis- mitory accommodations and shared facilities. Study Camp are some of my most rewarding try as we could. Every day, we woke up at 7 The international competition consists of professional relationships and friendships. I a.m., ate breakfast together, attended lectures two 5-hour exams. We all wanted to do well am still in contact with all of the mentors and from 8 a.m. to noon, had lunch, and then on the exams, but it was also important to live some of the students with whom I spent time had lab from 1 p.m. to 5 p.m. At night, there the experience: Imagine being in a different in 2004. was no computer or television, so we spent country, with students from around the world The chance to represent the United States time studying more, playing cards and word who share your interests—it’s rare to have an at the International Chemistry Olympiad games, and getting to know each other. It’s opportunity like this. helped me realize what a truly universal lan- a very intense experience—you are with the guage chemistry is. Because of same 19 people all the time, working together our mutual interest in chemistry, on chemistry. Toward the end of Study Camp, I made lifelong friends from all there is another qualifying exam—this time to over the world whom I continue decide who goes on the traveling team to the to run into at school and at con- international competition. ferences.

How did you find out whether you’d What does it take to made the traveling team? participate in the Chemistry At the end of Study Camp, there’s a ban- Olympiad? What advice do quet. Everyone’s parents flew in, and all the you have for interested mentors and professors from the camp were students?

there. It was very nice because it was the J o hn K t z The most important thing is first time in 2 weeks that we weren’t thinking J. L. Kiappes was the scientific observer in the U. S. delegation being dedicated. Some people to the 2007 International Chemistry Olympiad. Shown here are about studying for the next exam. But getting members of the delegation (wearing yellow T-shirts, from left have asked me if you need to chosen for the traveling team was on every- to right: Kara Pezzi, Sofia Izmailov, Justin Koh, Brian Lee, John take college classes to prepare one’s minds. It was the big elephant in the Kotz, Kenneth Brewer, and J. L. Kiappes) with Russian guide Daria for the exams—you don’t. But Tsareva (wearing a blue T-shirt). room. After dinner, everyone gets an award you need to put in the time to for participating, and then they announce two understand chemistry, not just alternates for the traveling team, and finally, Tell us about how you received your memorize facts. You have to have a real pas- the four members of the traveling team. I’d silver medal. sion for chemistry to do this—you have to had a great experience at Study Camp, but I At the end of the competition, there is a think about it a lot, and if it’s not something didn’t think there was any way I had made the closing ceremony which is a lot like the one you truly enjoy, you won’t be able to stick traveling team—but then they called my name at Study Camp. There is a dinner, and then with it. But if you put in the time to learn as one of the four. I was in such complete they announce all the awards. Everyone gets and understand it, you’ll have a good shot at shock that my mom had to tell me to get up to a certificate of participation, and then they success. join the team! Earning a spot on the traveling announce the medals: bronze, silver, and then team was a huge honor and surprise. gold. You don’t want to hear your name as long as possible, because everyone’s name Once you had been selected for the gets called. The later you hear your name, the better you did. When I heard my name for Christen Brownlee is a science writer in Baltimore, traveling team, what happened next? Md. Her latest article “What Uuought to Know Everything happened really quickly—in the the silver medal, it was unbelievable! I was About Elements 112–118,” appeared in the October few weeks before we left for the international incredibly excited. 2009 issue of ChemMatters.

18 Chemmatters, DECEMBER 2009 www.acs.org/chemmatters Interested in Competing for the National Chemistry Olympiad? Here Is a Chance to Test Yourself!

By Arden Zipp

he National Chemistry Olympiad is a U.S. competition designed to test students’ understanding of chem- istry concepts learned in class. For the past several decades, approximately 10,000 students enter local TChemistry Olympiad competitions vying for a chance to compete at the national level. Of those, approxi- mately 1,000 students are selected to take the national exam. Twenty of the highest-scoring students on the national exam are chosen to spend 2 weeks in a Study Camp at the U.S. Air Force Academy in Colorado Springs, Colo. Based upon their performance on exams and laboratory exercises, four students are selected to represent the National Chemistry Olympiad. These students then represent the United States at the International Chemistry Olympiad, a worldwide competition among high school chemistry students. Not only do the national exam’s questions test students’ knowledge of chemistry, but they also test students’ logic and creativity. For example, here is a question that appeared on Part II of the National Chemistry Olympiad in 2003:

How many different isomers have the formula C4H10O?

The term “isomer” refers to substances and In addition to inserting the oxygen atom in that have the same chemical formula but dif- the chain of carbon atoms, it can be part of a ferent structures. In the case of C4H10O, the CH3OCH2CH2CH3 hydroxyl (-OH) group, thus creating molecules number of isomers is eight. called alcohols. One such molecule is Here are four of them. The other four can are not isomers because each contains a single carbon atom joined to a 3-carbon chain be found on ChemMatters’ Web site: http:// CH3CH2CH2CH2OH www.acs.org/chemmatters. through the oxygen atom. They are the same! First, the oxygen atom can be inserted into Other isomers of this type exist. Since the This is the fourth isomer. the chain of carbon atoms in one of two ways: 3-carbon atom chain can be connected to the oxygen atom via either one of the carbon The other four isomers are at: CH3CH2CH2OCH3 atoms on the end of this chain or through the http://www.acs.org/chemmatters. central one, there is one more isomer: or If you would like to test yourself with more questions from past National Chemistry Olym- CH CH OCH CH CH3 3 2 2 3 | piad exams, you can go to: HCOCH3 http://www.acs.org/olympiad and click on These two molecules are isomers because | “Past Exams” on the top left. Enjoy! the oxygen atom is inserted into the carbon CH3 If you find yourself answering many ques- chain at different points: In the first molecule, tions correctly, you may want to enter the the oxygen atom divides the four carbon local Chemistry Olympiad competition by con- atoms into shorter pieces, one with a single has a different structure than tacting the coordinator of your local section of carbon atom and the other with three carbon the American Chemical Society or by sending atoms; in the second molecule, the oxygen CH3CH2CH2OCH3. an e-mail message to [email protected]. atom divides the four carbon atoms evenly with two carbon atoms in each segment. So, that’s a total of three isomers. These Arden Zipp is a Distinguished Teaching Professor at On the other hand, the molecules isomers are called ethers, because the oxygen the State University of New York, Cortland, NY, and atom is in the carbon chain. chair of the American Chemical Society’s Olympiad Examinations Task Force, which prepares and CH3CH2CH2OCH3 grades the U.S. National Chemistry Olympiad.

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