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OCTOBER 2012

Amazing Get Ready for Its Life- Changing Applications! p. 6

A Reversal of Fortune for Type 1 Diabetes, p. 9 Weather Myths: True or False? p. 14 www.acs.org/chemmatters Production team Patrice Pages, Lead Editor Cornithia Harris, Art Director Therese Geraghty, Copy Editor

Administrative team Marta Gmurczyk, Administrative Editor Peter Isikoff, Administrative Associate NEWS technical review Seth Brown, University of Notre Dame David Voss, Medina High School, Barker, NY teacher’s Guide William Bleam, Editor Check Out the ACS ChemClub Cookbook! Donald McKinney, Editor Erica K. Jacobsen, Editor Ronald Tempest, Editor Afternoon snack attack. A cookie craving hits. You’re out of store-bought cookies, so you Susan Cooper, Content Reading Consultant decide to bake your own. You fl ip through a cookbook; Grandma Button’s Favorite Molas- David Olney, Puzzle Contributor ses Cookies sound good. A quick look at the list of ingredients shows what you will need education division Mary Kirchhoff, Director to grab—a matured ovum with yolk overlaid with albumen proteins from Gallus domesticus Terri Taylor, Assistant Director, K–12 Science female? Dried and powdered rhizome of Zingiber officinale? What? Policy Board This recipe is one of dozens that you will fi nd in the recently pub- Ami LeFevre, Chair, Skokie, IL Shelly Belleau, Thornton, CO lished American Chemical Society (ACS) ChemClub cookbook. The Steve Long, Rogers, AR Mark Meszaros, Rochester, NY Club from East Syracuse–Minoa High School in East Syracuse, NY, Scott Goode, Columbia, SC submitted the recipe described above. To successfully make the ChemMatters (ISSN 0736–4687) is pub- cookies, the reader needs to translate “science speak” into the lan- lished four times a year (Oct, Dec, Feb, and April) by the American Chemical guage of the kitchen, connecting chemistry with cooking. Society at 1155 16th St., NW, Washington, DC 20036–4800. Periodicals postage paid During the 2011–2012 school year, ACS ChemClub members at Washington, DC, and additional mail- experimented in the kitchen and submitted their favorite recipes. ing offices. POSTMASTER: Send address changes to ChemMatters Magazine, ACS In the cookbook, these range from family favorites to recipes Office of Society Services, 1155 16th St., NW, Washington, DC 20036. representing different

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Vol. 30, no. 3 OctOBer 2012

DEPARTMENTS Did You Know? 4 Noble Gases: Xenon Reacts! Chemistry of : Going Up! Open for Discussion: Nanoparticles 5 By Barbara Sitzman and Regis Goode Nanoparticles are clusters of a few hundred to a few thousand that

promise to change our lives in unique and useful ways. COpYRIGHT2007pHYSORG.COM. ALL RIGHTS RESERVED; HTTp://M.pHYS.ORG/pARTICLES-SHApES- METHOD_NEwS104677694.HTML 5 6 FEATURES Traducción en Graphene: The Next Wonder Material? 6 español By Michael Tinnesand disponible en Graphene, the thinnest known material, could be used to make foldable cell Internet phones, and fl exible solar panels, and devices that help people with spinal cord injuries regain use of their limbs. CRUNCHwEAR.COM 9 Diabetes: Tiny Particles to the Rescue 9 By Roberta Baxter People with type 1 diabetes—many of them teenagers—need to check their blood sugar fi ve to seven times per day and give themselves an average of fi ve Check out the video podcast about graphene at: insulin injections every day. Relief from this demanding routine may be on the www.acs.org/chemmatters way, thanks to scientists who are working on a vaccine based on nanoparticles.

(Un)Stuck on You 12 pHOTOS.COM By Renée Heiss Static cling causes your clothes to cling to your body and clothes to stick to one 12 14 another after being washed and dried. So, how do you get rid of static cling? A type of fabric called a nanotextile may be the answer. Weather Folklore: Fact or Fiction? 14 By Brian Rohrig Many expressions about the weather have been passed down through the ages. Are any of them true? We look at the science (and chemistry) behind four such expressions… and learn about how the weather works! pHOTOS.COM

“Chance Favors the Prepared Mind”: Great Discoveries pHOTOS.COM in Chemistry 17 By Gail Kay Haines Three scientifi c discoveries—those of urea, radioactivity, and buckyballs—have transformed our modern world. We tell you the intriguing personal stories of the scientists who, against all odds, made these remarkable discoveries. FREE! TEACHER’S Guide! Find a complete teacher’s guide for this issue at: www.acs.org/chemmatters

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Chemmatters, OCTOBER 2012 3 DID YOU KNOW?...DID YOU KNOW?...

Noble Gases: Xenon Reacts!

nreactive, inert, does Canada, formed an interesting “Unot form compounds.” precipitate with a deep red color. Until 50 years ago, that was the He and a graduate student began description found in chemistry investigating the compound and textbooks for the noble gases, discovered that it was a com- a group of six elements found bination of an anion, platinum – on the right side of the periodic hexafluoride (ptF6 ), and a cation + table—helium, neon, argon, (O2 ). krypton, xenon, and radon. Unlike every other oxygen- Noble gases are mono- containing compound, in which atomic—they consist of a single oxygen is the negatively charged —because they have full ion, in this red solid, oxygen is HTTp://EN.wIKIBOOKS.ORG/wIKI/STRUCTURAL_BIOCHEMISTRY/NOBLE_GASES outer electronic shells, which positively charged. The reason makes them unlikely to gain or for this difference is that the this idea. He built a glass con- He initially assigned the lose electrons. Chemists thought platinum hexafluoride ion is more tainer with two parts to hold a orange-yellow solid as XeptF6, + they would not ever react, but electronegative than oxygen. different gas in each, with a seal a simple salt containing Xe and – a young chemist proved them Bartlett began to think that between the two parts. ptF6 . Later studies have shown wrong and introduced a whole if platinum hexafluoride could “when I broke the seal that the actual solid is more com- new set of compounds made by pull electrons away from oxy- between the red ptF6 gas and plex, but all agree that Bartlett reacting noble gases. gen atoms, it might as well pull the colorless xenon gas, there had succeeded in preparing the In 1958, Neil Bartlett, a lecturer electrons away from xenon, one was an immediate interaction, first chemical compound of a in chemistry at the University of the noble gases. So, Bartlett causing an orange-yellow solid to noble gas. of British Columbia, Vancouver, planned an experiment to test precipitate,” he later wrote. —Roberta Baxter

Chemistry of Carbon: Going Up!

ou step into an elevator, the carry large loads. Such a strong The carbon atoms in a nano- Ydoors close, and the eleva- cable could be made with a type tube link together in hexagons, tor begins to move. Sounds like of material called a nanotube, giving it a rigid structure that is a routine occurrence, except that which is a sheet of carbon graph- stronger than steel but weighs the next stop for this elevator is ite rolled into a cylinder. Nano- much less than steel. space. tubes are so small they cannot If nanotubes could be linked NASA and the Spaceward be seen with a microscope. Their into a cable that would be long Foundation, a nonprofit organi- diameters are only a few nano- enough, it could be used in a zation dedicated to space sci- meters long. One nanometer is space elevator. The carbon nano- ence and education, support a one-billionth of a meter, and one tube cable would be attached to competition to encourage teams micrometer is one-thousandth of a point on Earth, while the other of engineers to build a space a meter. A strand of hair is about end would stretch 25,000 miles elevator to lift people and cargo 100,000 nanometers, or 100 into space. At that height, the into space at a lower cost than micrometers, in diameter. cable would turn at the same rockets. The latest competition Graphite is a form of carbon rate as the Earth, staying above took place in August 2012. present in pencil lead. In it, layers the same point. Robotic climbers One of the most important of carbon atoms link together, would move up the cable, carry- items needed is a cable strong and these layers are loosely con- ing cargo or people. enough to reach into space and nected to each other. —Roberta Baxter [email protected]

4 Chemmatters, OCTOBER 2012 www.acs.org/chemmatters By Barbara Sitzman OPEN FOR DISCUSSION and Regis Goode

NANOPARTICLES How small are nanoparticles? Are nanoparticles “Nano” is the metric prefix for 1 x 10-9, so a nano- really new? meter (nm) is a billionth of a meter. It comes from Actually, nanoparticles were an ancient Greek word that means “dwarf.” Nanopar- already there when the Earth was ticles range from 1 to 100 nm in diameter. without formed. Sea spray and volcanos a microscope, we can only see particles larger than spewed nanoparticles into our 10,000 nm. atmosphere. In the 9th century, COURTESY OF THE NATIONAL CENTER FOR ELECTRON MICROSCOpY, LAwRENCE BERKELEY NATIONAL Mesopotamian artisans created LABORATORY, US DEpARTMENT OF ENERGY; HTTp://www.SpH.SC.EDU/NEwS/ABOUTNANO.HTM their pottery glitter with copper and silver oxides finely ground to Would you buy a roll-up nano-size. smart phone? what is new about nanoparticles Check out is our ability to manipulate matter at Paper-thin smart phones are still on the atomic level, opening the door the research lab bench. Soon, SHUTTERSTOCK to many new applications. During you may be able to twist online: the past 5 to 6 years, research, nanophones to fi t your www.acs.org/ development, and consumer inter- est has been increasingly focused pocket. T-shirts with carbon chemmatters on nanotechnology. nanotubes woven into the fabric are expected to keep them charged. Breath sensors could soon replace blood analyses Why nanoparticles are so special You feel feverish and miserable, and when the diameter of particles Nanoparticle clusters have a then your doctor orders tests. But who is 100 nm or less, their chemi- large surface-to-volume ratio. likes needles stuck into their veins to cal and physical properties are This means that most of their withdraw a tube of blood? Some clinics unique and quite different from atoms sit on the surface, avail- already quickly and painlessly analyze N A N O materials made with the same able to collide and ready to react. the gases you exhale for flu viruses. Breath LE TT TY ER IE S, OC chemical elements but large These small reactive clusters AME L S sensors, composed of gold nanoparticles, RICAN CHEMICA enough to see. Nanoparticles’ could one day zoom through our carbon nanotubes, and silicon nanowires, Flu viruses can be unique characteristics are bloodstream for speedy drug help doctors diagnose various medical detected by breath strongly influenced by their size delivery or to attack cancerous sensors made with silicon conditions by analyzing breath in just a few nanowires that are present and shape. tumors. seconds. in this face mask. In addition to size, scientists are discovering that the shape of a nanoparticle mat- Should we be concerned about nanoparticles? ters. Flat disks bond best to tumors, and rod-shaped We are not fully aware of the health and environmental risks nanoparticles slip into cells presented by the use of nanoparticles. But scientists are trying to at four times understand the potential risks and benefi ts of their the rate of widespread use. cylindrical What questions are left in your mind? What do you think? nanoparticles. To keep up-to-date on recent advances in nanotechnology, please go to the Web site of the National Nanotechnology Initiative, the main federal nanotechnology program: http:// www.nano.gov/. COpYRIGHT2007pHYSORG.COM. ALL RIGHTS RESERVED; HTTp://M.pHYS.ORG/pARTICLES-SHApES-METHOD_NEwS104677694.HTML

Nanoparticles with various shapes pHOTOS.COM

Chemmatters, OCTOBER 2012 5 Graphene The Next Wonder Material?

By Michael Tinnesand

here is a new wonder material in town that that is ejected to the surface from deep within SHUTTERSTOCK might change our future. Imagine a coffee the Earth’s interior through volcanic eruptions, cup that streams the day’s headlines in while graphite is a black and lightweight mate- real time. Or a cooking pot that can detect rial extracted from coal. be only a single one-atom thick layer—pure the presence of E. coli bacteria that could In diamond, each carbon atom is connected graphene. make you sick. Or a television screen that to four other . This is a very strong The initial samples of graphene were very Tis as flexible and thin as a piece of paper. All arrangement that makes diamond one of the small—only a couple of square millimeters in of these applications could be a reality if the hardest known materials. In graphite, each size each—but large enough to test. Because wonder material, named graphene, lives up to atom is linked to three others in layers of graphene is only one-atom thick, it is con- its hype. hexagonal (six-sided) shapes that look like sidered to be a two-dimensional material, the chicken wire (Fig. 2, p. 8). The bonds within first example of such a thing in the real world. Chicken wire made the hexagonal sheets are strong, but each Despite being the thinnest material known of carbon layer is only weakly attracted to the next, to exist, it is also the strongest material ever which allows the layers to slip by one another. tested—100 times stronger than steel. Graphene rocked the world of chemistry in In 2004, Andre Geim and Konstantin Even more amazing: Electrons do not 2004 when scientists discovered that it had Novoselov, two chemists at the University scatter as much when they move as they do remarkable properties: It conducted electricity of , United Kingdom, used this in other materials, such as silicon. This led better than any other common substance, it property to produce samples of graphene researchers to make graphene-based transis- was the thinnest known material—only one- and discover its remarkable properties. They tors that are twice as fast as traditional silicon atom thick—and it was stronger than steel! transistors, which could make computers run After all, carbon is one of the most com- much faster. mon and most familiar of the known chemical elements, so scientists were surprised to find Flexible solar panels that this new form of carbon had such amaz- ing properties. Graphene has sparked the interest of Carbon comes in many crystalline forms, engineers who are trying to make new, light- called allotropes, the most well-known being weight, and flexible solar panels that could be used to cover

diamond and graphite. Allotropes are differ- CHRIS LASSIG, L ost in S cience , htt p:// los - tinscience . files .w ord p ress com /2012/02/ p e .jp g gra p hite - ta ent forms of the same element with different Sticky tape can be used to peel off powdered the outside surface of a bonding arrangements between atoms, result- graphite, leaving a single layer of graphene. building, in addition to the ing in structures that have different chemical used sticky tape to separate the layers of roof—which is already and physical properties. The way atoms are carbon in graphite. To get an idea of how their being used. connected to each other in solid materials has technique worked, think of pressing sticky Graphene is nearly a huge impact on their overall properties. tape onto a piece of graphite and pulling it transparent to light—not A diamond and a piece of coal are so dif- only visible light but also away, leaving the sticky surface covered with Crunchwear.com ferent that you would never guess that they graphite flakes. Then, press the sticky tape to are both made of the same element—carbon. Solar panels on these backpacks can charge itself and pull it apart. Repeat, and after a few your mobile phone or iPod. In the future, flexible Diamond is a hard and transparent mineral rounds of this, some flakes on the tape will solar panels may even charge your laptop.

6 Chemmatters, OCTOBER 2012 www.acs.org/chemmatters mation is relayed to a processor inside the device, which determines what kind of action to take. All of this is possible because these devices use screens that have thin and transparent coatings that are conductive and can hold a charge. Most portable devices today have screens that are coated with a conductive layer made of indium tin oxide. But this material is brittle, so it is layered on glass to protect and support it. This leads to thick and inflexible displays. Touch screens made with graphene as their conductive element could be printed on thin plastic instead of glass, so they would be light and flexible, which could make cell phones as thin as a piece of paper and foldable enough to slip into a pocket. Also, because of gra- phene’s incredible strength, these cell phones would be nearly unbreakable. Scientists

TOUCH BIONICS expect that this type of touch screen will be the first graphene product to appear in the other forms of electromagnetic radiation, pCs have touch screens that allow the user to marketplace. including ultraviolet and infrared light. Gra- make selections by touching icons or letters phene absorbs only 2% of the light falling on directly on the display screen. Bionic devices it, whether it is ultraviolet, infrared, or all of The basic idea of how most of these Because graphene is thin and flexible, it the wavelengths in between. Combine this devices work is simple. A layer that stores could be integrated into “bionic” devices that with graphene’s ability to conduct electricity, electrical charge is placed on the glass panel and you have very efficient, electrical conduc- of the screen. when a user touches the tors that are transparent, thin, flexible, and screen with his or her finger, or with a stylus cheap. pen, some of the charge is transferred to the This new type of solar panel is currently user, so the charge on the layer decreases. under development and consists of organic This decrease is measured by sensors located photovoltaic cells sandwiched between sheets at each corner of the screen, and this infor- of graphene (Fig. 1). A photovoltaic cell is a MEI zHANG, UNIVERSITY OF TEXAS AT DALLAS MEI zHANG, UNIVERSITY OF TEXAS AT small device that converts the sun’s energy Nanoscale fibers drawn from into electricity. multiwalled carbon nanotubes have when a photovoltaic cell is sandwiched strengths comparable to spider silk. When they are stretched, between two sheets of graphene, light Negative contact they increase in width (instead of crosses the sheets of graphene and hits the Current flow getting thinner), so they might be photovoltaic cell. As a result, the photovoltaic used to make artificial muscles in Electrons the future. cell generates electricity, which is carried by the sheets of graphene. Silicon Photon These lightweight and flexible solar panels Electron would be implanted in living tis- could be molded to fit an automo- flow Hole sue. The term “bionic”—a mix bile body or be wrapped around of “biology” and “electronic”— furniture or clothing. when added Positive refers to devices that help or to any surface, they could collect contact improve an organ or tissue, such light and produce electricity. as artificial hearts or cochlear

ANTHONY FERNANDEz implants, which assist people Figure 1. Schematic representation of a new type Foldable cell of solar cell that consists of a photovoltaic cell with hearing loss. phones sandwiched between two sheets of graphene. Graphene is resistant to the salty ionic solu- When light crosses the graphene and is absorbed tions inside living tissue, so bionic devices Until recently, most electronic by the silicon, the photons that make up the light made of graphene could have long shelf lives, devices were controlled by pushing excite electrons in the silicon, which migrate to the graphene sheet at the negative contact and perhaps lasting a lifetime. This is in contrast buttons, typing on a keyboard, or using move through the graphene structure toward an to metallic parts that can corrode after a few a mouse. Today, most cell phones and tablet external circuit that produces electricity.

Chemmatters, OCTOBER 2012 7 (a) (b) (c)

Carbon Oxygen Sulfur Hydrogen

(d) (e) (f) anthony fernande z and p hotos . com

Figure 2. Atomic structures of six common forms of carbon: (a) coal, (b) graphite, (c) diamond; (d) buckyball; (e) nanotube; and (f) graphene. Photos of pieces of coal, a golf club made with graphite, and a diamond ring are examples of products made with the first three forms of carbon. Products made with buckyballs, nanotubes, and graphene are still under development. years, possibly releasing toxic metals into the Available soon? In another method, the graphite is dis- body. solved in a solvent and then sprayed in thin You may have noticed that the words Also, because graphene conducts electrical layers using inkjet-type printers. The solvent “might” and “could” were used many times in signals, it can be connected with neurons, evaporates, and the graphene remains. this article. That is because there is still a long which also send weak electric signals from But none of these methods has been per- way to go before any of these applications cell to cell. These electric signals are cre- fected, as yet. The race is on to be the first to comes true. ated when a nerve cell pumps ions—mainly show whether this wonder material can live up One of the obstacles that needs to be sodium ions (Na+) and potassium ions (K+)— to its potential! overcome is how to make sheets of graphene in or out of the cell, causing a difference in large enough and pure enough (containing electric potential inside and outside the cell. carbon) to be useful. Any non-carbon Selected references For example, imagine putting transistors just atoms can disrupt the perfect hexagonal Brody, H. “Graphene,” Nature Outlook, Supplement made of graphene along a damaged spinal pattern for graphene. Many of the samples to Nature, March 15, 2012, 483 (7389), pp cord. Such transistors could detect nerve S30–S44: http://www.nature.com/nature/ produced for research are only a few square impulses in the undamaged section of the outlook/graphene/ [accessed Aug 2012]. millimeters in size, but sheets of up to 76 spinal cord and conduct them past the dam- Geim, A. K.; Kim, P. Carbon Wonderland, Scientific centimeters across have been reported, and American, April 2008, 299, pp 90–97: http:// aged area to the nerves in muscles. This www.nature.com/scientificamerican/journal/ breakthroughs seem to emerge every month. could allow people to regain the use of their v298/n4/pdf/scientificamerican0408-90.pdf The key is for the layer to be one-atom arms or legs after a spinal cord injury. [accessed Aug 2012]. thick and to have all of its atoms in perfect This type of technology could be used to six-sided rings. This is very difficult to control Michael Tinnesand is a science writer and educa- control a mechanical artificial arm or leg. In when producing pure crystals. One commonly tion consultant who lives in Portland, Ore. His latest mechanical limbs, small motors are used ChemMatters article, “A Super Vision for Airport used method, called chemical vapor deposi- instead of muscles to create movement. The Security,” appeared in the February 2012 issue. tion, consists of passing methane (CH ) gas graphene bionic device could relay electrical 4 over a sheet of copper. At high temperatures signals to the small motors in an artificial (800 °C–1000 °C), the methane deposits its limb, making it move. Check out the video carbon—ideally in perfect hexagonal sheets— podcast on graphene at: and the hydrogen is released. www.acs.org/chemmatters

8 Chemmatters, OCTOBER 2012 www.acs.org/chemmatters Tiny Particles to the Rescue

DiabetesBy Roberta Baxter

or a while, Amanda felt that something was wrong with her. No matter how much water or juggle her insulin dosage, diet, and exercise. soda she drank, she was always thirsty. And then, there were the never-ending trips to the A promising new treatment may be in sight bathroom. She was always tired and, over the previous two weeks, she lost 15 pounds. that might relieve Amanda and other people Alarmed, her parents scheduled a visit with their family doctor, who checked her blood living with type 1 diabetes from worrying sugar level through a urine test. The test revealed that her blood sugar was much higher than about their blood sugar level all day long. If average,F and indicated the presence of compounds called ketones. this treatment becomes a reality, Amanda “The doctor was shocked because my blood sugar level was so high, even though I hadn’t had would take a medicine several times a year breakfast,” Amanda says. “When she saw that ketones were present in the blood, she immediately that would allow her body to produce the called the local hospital, and I was rushed to the hospital five minutes later. I was scared because I insulin that she needs. This new treatment is was wondering if I was going to die.” still in development, but the early results are At the hospital, the doctors encouraging. tested Amanda’s blood sugar level every hour or so. The num- Too much blood bers (in milligrams per deciliter) sugar, not enough kept going up: 412, then 464, 520, 666, and so on. “Nobody insulin could tell me why my blood sugar The main issue faced by Amanda and other was so high, and the doctors people living with type 1 diabetes is the abnor- couldn’t get it down,” Amanda mally high blood sugar level, which results says. “I was crying, my parents from a lack of insulin in their bodies. Insulin is were worried, and I remember important because it regulates blood sugar by being really scared.” keeping its level below a certain amount—on p hotos . com Amanda stayed at the hospital Each year, more than 15,000 children and 15,000 adults are average, 300 milligrams per deciliter. for the next two days. She was diagnosed with type 1 diabetes in the United States. Insulin is produced by the pancreas—a put on a special diet, while doc- small organ located near the liver—and is tors kept checking her blood sugar level, substance that decreases the body’s blood released into the bloodstream. When the blood which finally went down. Then the diagnosis sugar level. People with type 1 diabetes pro- sugar level is high, insulin causes cells in the came: She had type 1 diabetes. “I was ter- duce little or no insulin, which explains why liver, muscle, and fat tissue to take up sugar rified,” Amanda says. “I had no idea what it their blood sugar level is so high. from the blood, so it does not build up in the was, but I could tell from the sound of the It has been seven years since Amanda was bloodstream. The cells then use the sugar to doctor’s voice that it was bad news.” first diagnosed with type 1 diabetes. She has produce energy. When insulin is absent or low, After being discharged from the hospital, learned to adjust her daily activities to the sugar is not taken up by the body cells, and it Amanda met with other doctors who helped demands of the treatment, but sometimes builds up in the bloodstream. her manage the disease. Amanda was told she just wants to forget about it and enjoy her Insulin is a type of hormone, a substance to carefully watch what she ate and regularly day. On other days, she struggles to keep her released in the blood by a gland in one part check her blood sugar five to seven times blood sugar level at a normal range. Amanda of the body, which affects cells in other parts per day, while self-injecting an average of hopes that, one day, a cure for the disease of the body. The chemical structure of insulin five doses of insulin per day. Insulin is a will be found, so she won’t have to constantly is that of a polypeptide (Fig. 1), an organic

chemmatters, OCTOBER 2012 9 A – chain SS The main culprit in this case is a type of immune cell called an aggressive T Gly Ile Val Glu Gln Cys Cys Thr Ser Ile Cys Ser Leu Tyr Gln Leu Glu Asn Tyr Cys Asn cell, which attacks insulin-producing cells. When the insulin-producing cells 123456 78 91011121314151617181920 21 SSare destroyed, the body does not pro- duce the insulin that it needs to regulate B – chain SSits blood sugar level.

Phe Val Asn Gln His Leu Cys Gly Ser His Leu Val Glu Ala Leu Tyr Leu Val Cys Gly A cure may be in 1234567891011121314151617181920 Glu sight 21 Thr Lys Pro Thr Tyr Phe Phe Gly Arg Scientists are investigating a new type of treatment that uses very small 30 29 28 27 26 25 24 23 22 particles called nanoparticles—clusters Figure 1. Insulin is a polypeptide hormone made of units called amino acids, which are indicated here with their of a few hundred to a few thousand common abbreviations: Gly (glycine), Ile (isoleucine), Val (valine), and so forth. atoms. Nanoparticles are less than 100 nanometers in diameter, and one nano- compound with the structure R-CO-R', where meter is one-billionth of a meter. In com- (a) H (b) H R and R' are carbon chains, and it is produced parison, a strand of hair is about 100,000 when the body breaks down fat. Two ketones nanometers in diameter. H N C COOH H N C COOH 2 2 are produced by the body under these circum- The advantage of nanoparticles is that they stances: acetone (CH3-CO-CH3) and acetoace- can be coated with molecules designed to CH2 CH2 tic acid (CH3-CO-CH2-COOH). recognize and attach to specific cells in the OH SH Breakdown of fat also leads to a third body. The scientists, led by Pere Santamaria, substance, called 3-hydroxybutyric acid (CH - a professor at the Julia McFarlane Diabetes Serine Cysteine 3 (Ser) (Cys) CHOH-CH2-COOH) (which is not a ketone, Research Centre, University of Calgary, but a carboxylic acid). Acetone, acetoacetic Alberta, Canada, used nanoparticles to stop Figure 2. Examples of two amino acids: (a) acid, and 3-hydroxybutyric acid are known the aggressive T cells that attack insulin- serine and (b) cysteine. All amino acids have two as ketone bodies. Two of them (acetoacetic producing cells in the pancreas. functional groups, the amino group (–NH2) and the carboxyl group (–COOH), both of which are acid, and 3-hydroxybutyric acid) are used as The nanoparticles, which are thousands covalently bonded to a central carbon atom. The a source of energy, while acetone is excreted of times smaller than the size of a cell, were central carbon atom is also bound to a hydrogen by the body. coated with peptide fragments, which are atom and a group that varies depending on the amino acid. The reason Amanda’s body produces so lit- small parts of protein molecules. These pep- tle insulin is that her immune system attacks tides are bound to molecules that latch onto the cells that create insulin in her pancreas. immune cells called regulatory T cells. These molecule made of units called amino acids For this reason, type 1 diabetes is an auto- regulatory T cells then shut down the aggres- (Fig. 2). immune condition, in which the body mistak- sive T cells. Insulin binds to receptors on the surface of enly recognizes its own tissues as foreign and So, when the nanoparticles were injected cells in the liver, muscles, and fat tissues. This attacks them. in mice, they latched onto their regulatory T causes a protein present inside the cell mem- brane, called a transport protein, to bind to

the sugar molecule, or glucose (C6H12O6), and Glucose molecules to carry it inside by moving it through the cell Insulin molecules membrane (Fig. 3). As the sugar molecules are absorbed by the cells, the blood sugar Insulin receptor level returns to normal.

When Amanda turned 10, her body started Glucose transporter producing less and less insulin, to the point that most of the sugar molecules in her blood were building up, instead of being used by her cells. This led to the symptoms described earlier—thirst, an excessive need to go to the bathroom, and weight loss. The presence of ketones in her urine was another warning sign, because they indicated Figure 3. When insulin molecules bind to receptors on the surface of a cell, they activate other molecules that Amanda’s body was using fat—instead inside the cell (black arrows inside the cell) to allow a protein, called a glucose transporter protein, to

all figures by anthony fernande z of sugar—to produce energy. A ketone is a bind to glucose and carry it inside the cell.

10 Chemmatters, OCTOBER 2012 www.acs.org/chemmatters Glucose Glucose molecules molecules

G G G G G Blood G Blood G G Carbohydrates G vessel Carbohydrates G vessel G G G G G G (from food) are G G (from food) are G G

broken down into G broken down into G glucose molecules Stomach glucose molecules Stomach G G

G G G G I I I I G I G I I I I G I I I I I I G G G Less glucose goes G I G inside organ; instead, G I Insulin G it builds up I Agressive G I in the bloodstream I G I I G T cells G G I I G I G I G I

I I G G I

G I

Muscles G I Liver Muscles Liver

Insulin-producing Insulin-producing — Extreme thirst cells cells destroyed by agressive T cells — Frequent urination — Sudden weight loss — Labored breathing, etc. anthony fernande z (A) In a person without type 1 diabetes, the hormone insulin is secreted by the pancreas in the bloodstream so it can move sugar molecules into the cells of the body’s tissues, such as muscles and the liver, pictured here. (B) In a person with type 1 diabetes, the pancreas cannot produce insulin because most or all of the cells in the pancreas that produce it have been destroyed by aggressive T cells (in green). The presence of little or no insulin prevents sugar from moving into the body’s tissues, so it builds up in the bloodstream instead, resulting in a high blood sugar level and the symptoms highlighted here.

cells, which, in turn, prevented the aggres- lin injections and blood tests, but it would still sive T cells from attacking the cells Why Ketones be such a huge relief if I didn’t have to do that produce insulin. As a result, in the Blood Are so, day in and day out. Deep down, that’s these cells were able to produce Dangerous what a lot of people with type 1 diabe- insulin, and the blood sugar tes truly wish for.” When Amanda’s urine test revealed the levels of these mice became normal. presence of ketones in her blood, her doctor “This study has pro- immediately called the nearest hospital. Why? Selected references vided proof-of-concept of The presence of ketones in the blood is a sign that Life with Diabetes for Teens, Juvenile a new therapy that could ketone bodies (defined on p. 10) are building up and Diabetes Research Foundation: prevent and reverse type are potentially making blood too acidic, which could http://www.jdrf.org/index. 1 diabetes,” says Teodora cfm?page_id=103445 [accessed be life-threatening. Here is why. The absence of Aug 2012]. Staeva, program director insulin leads to the release of free fatty acids which Share Your Story, Juvenile Diabetes of immune therapies at are converted in the liver into ketone bodies. These Research Foundation: http://www. the research center. ketone bodies are weakly acidic, so they turn the blood jdrf.org/index.cfm?page_id=116723 The nanoparticle treatment [accessed Aug 2012]. acidic. In the case of a person with type 1 diabetes, would prevent further damage Halim, N. Nanotechnology’s Big Impact, the body initially balances out the change, but it is ChemMatters, Oct 2009, p 15. to the insulin-producing cells quickly overwhelmed. If ketone bodies are not Green, L.; Kelly, P. I Have Diabetes. Now by resetting the immune system. What? Teen Life 411, Rosen Publishing: New “These nanoparticles would have to eliminated from a person’s blood, that York, 2012. be administered several times a year to person can die. Hood, K. K. Type 1 Teens: A Guide to Managing achieve the full effect of an immune system Your Life with Diabetes, Magination Press, American Psychological Association: that will not attack the insulin-producing cells Washington, DC, 2010. anymore and will return insulin production to of people diagnosed with type 1 diabetes. “If normal,” Staeva says. successful, this new treatment would drasti- Roberta Baxter is a science writer who lives in Colorado Springs, Colo. Her most recent The nanoparticle treatment may someday cally change how I manage my disease,” ChemMatters article, “H2GO: Hydrogen In, Water radically change Amanda’s life and the lives Amanda says. “I am now used to these insu- Out,” appeared in the April 2011 issue.

chemmatters, OCTOBER 2012 11 (Un)Stuck

OnBy Renée HeissYou

pHOTOS.COM

sn’t it embarrassing when your pants or As you know, many materials are made of An antistatic agent, such as fabric soft- skirt cling to every curve of your body? atoms that are electrically neutral because they ener, reduces or eliminates buildup of static IOr when you fold laundry, and clothes are contain equal numbers of positive charges electricity by attracting water molecules to stuck to each other, making it harder to find (protons in their nuclei) and negative charges the surface of fabrics. The molecules of an small items such as socks. And if you have (electrons surrounding the nucleus). But antistatic agent often have both a hydro- pets—especially white cats or dogs—their when two materials are in contact, sometimes phobic side, which repels water molecules, hair will always stick to your black pants. electrons move from one material to the other, what most people do is use a fabric softener especially when one of the materials has when they wash their clothes, but this solution weakly bound electrons—and tends to lose is temporary because once the fabric softener them—and the other material has sparsely rubs off, the clothes start clinging again. filled valence shells and tends to gain elec- In the near future, clothing could be made trons. Then, when the materials are separated, with a fabric that removes static cling, mak- one of them keeps the extra electrons and is ing such clothes “static-free.” Dresses and negatively charged and the other is positively pants made with this fabric would not cling charged because it lost electrons. This is to your body anymore, and when they are known as the triboelectric effect. pHOTOS COURTESY OF KAITLIN SAENz pHOTOS COURTESY washed, they would not bind to other clothes. Static cling makes your clothes stick to your body This fabric would contain nanoparticles—very (left). Using fabric softener or wearing clothes made with nanotextiles eliminates static cling (right). small particles that have amazing properties and hold promise for a variety of applications, such as drug delivery, medical imaging, and house-cleaning products. A Naturally Static- Resistant Fabric What is static cling? Are there naturally static-resistant textiles? Of all the fi bers, both nat- Before taking a look at these static-free ural and synthetic, the answer would be wool because it absorbs water clothes, let’s see why static cling occurs in the first place. You probably had firsthand more readily than any other fi ber. It can store water vapor up to 35% of experience with static electricity when you its own dry weight yet it remains dry to touch, which makes it the per- received an electric shock after turning a fect choice for hikers’ socks. the water vapor surrounding the wool acts doorknob or when you pulled your bed cov- like nanotextiles with their thin layer of atoms. Wool also behaves like a ers up and they made sparks. But while these effects of static electricity can be experienced garment that has been treated with fabric softener. Wool is nature’s own by anyone, the cause of static electricity is static-resistant fi ber, but it is not static-proof like nanotextiles.

not as obvious. That’s because it is happen- pHOTOS.COM ing at the atomic level.

12 Chemmatters, OCTOBER 2012 www.acs.org/chemmatters and a hydrophilic side, which attracts water may have seemed far-fetched at the time (in The future molecules. The hydrophobic side interacts the 1950s), but it worked! It took decades of with the surface of the fabric, while the hydro- experimentation until garment manufactur- Eliminating static charge buildup is also a philic side interacts with the water molecules ers were able to find an antistatic substance concern in other areas. Manufacturers of elec- present in air moisture. Because the water called a carbon nanotube. Clothing items tronic products try to eliminate as much static molecules are polar, they bind to the electric made with this substance are not only static- cling as possible to prevent the attraction of charges on the surface of the fabrics and free, but they are also comfortable to wear, small particles of dust to electronic devices. attenuate their attraction to oppositely charged and the fabric is neither bulky nor clammy. Airplane fuel has antistatic additives to pre- particles, thus reducing static cling. A carbon nanotube is a cylindrical carbon vent static electricity sparks that could ignite Fabric softeners also lubricate clothing— molecule formed by one sheet of graphite the fuel vapor. this is actually their primary role—which rolled up into a cylinder. Carbon nanotubes While we are waiting for antistatic nano- significantly reduces friction between different have unusual strength because every carbon textiles to hit the stores in the future, we can pieces of clothing and reduces the chances atom is connected to three other carbon still enjoy wearing other types of nanotextiles. that they will be in contact with each other and atoms, which makes a very strong bond. Look on the hang tag of your next pair of exchange electrons. Also, because fabric soft- eners attract water molecules in the air, the water-coated fibers in clothes slide along- side each other without fric- Triboelectric Effect tion, which is another reason aterials with sparsely filled valence shells tend to gain electrons are not released and static cling does not occur. Melectrons, while materials with weakly bound electrons Unfortunately, fabric soften- tend to lose them. This is known as the triboelectric effect and ers eliminate static cling only results in one material becoming positively charged and the temporarily. As a fabric soft- other negatively charged. ener naturally rubs off a fabric The relative attraction for electrons of various substances has through everyday use, the been studied experimentally. This led to a table called the tribo- clothes’ fibers become sus- electric series, which compares the strength of electric charges ceptible to static cling again. on various materials once they are separated (Table 1). The triboelectric effect is the main cause of static electricity. Nanotextiles Charge separation causes your hair to stand up and causes To eliminate static cling clothes to stick to one another after they are washed. more permanently, garment manufacturers have tried to coat fabrics with an antistatic _q ui z_09_10_1. htm sciencesource 2. ca / resources hot p otato htt p://www. finish during the manufactur- Table 1. Triboelectric series ing process. This way, clothes are already coated with an antistatic sub- When carbon nano- pants, dress, or jacket, stance that stays on them for a long time—if tubes are used with and see if you find any not forever. Unfortunately, this type of cloth natural fibers, they form reference to nanotextiles. You material feels stiff, and the coating process a strong, tightly bonded might be surprised at how well clogs the weave, making the fabric imperme- coating on each fiber. The it keeps you warm when it is able to air. When that happens, it does not fibers are then made into photos.com cold out and repels water when wick away perspiration, and people feel cold yarns that are woven into it rains! and clammy. fabrics. Because the nanotubes easily slip So, what’s next? Garment manufacturers past each other, the fabric feels soft, and the Selected references lack of friction also results in a lack of static Fabric Softener, eNotes: http://www.enotes.com/ decided to apply antistatic substances directly fabric-softener-reference/fabric-softener to the fibers that make up clothes. Fibers are discharge. [accessed Aug 2012]. the smallest visible unit of any textile product. Although scientists and garment manu- Nanotextiles: http://www.vice.com/en_uk/read/the- They are long, thin strands of material that facturers are still experimenting with such learning-corner-v18n3 [accessed Aug 2012]. are spun into yarn and made into fabrics. fabrics, clothes made with nanoparticles— Textiles and Clothing, NanoTox: http://www.nano- tox.com/industries/textiles-and-clothing.html They can be natural—such as cotton, silk, aggregates of atoms that have less than 100 [accessed Aug 2012]. and wool—or synthetic, such as polyester, nanometers in diameter—are commercially acrylic, and nylon. available. These clothes, called nanotextiles, Renée Heiss is a science author and retired teacher The idea of applying antistatic substances include waterproof clothing, stain-proof cloth who lives in Tabernacle, N.J. Her most recent seats, and lightweight sportswear. ChemMatters article, “Mmmm... Flavorful Food!” to individual fibers at the molecular level appeared in the December 2011 issue.

chemmatters, OCTOBER 2012 13 In warm air, the molecules of water vapor do not usually clump together because they have enough kinetic energy to overcome the forces of attraction among one another. But as the temperature cools, the water vapor molecules slow down and clump together, forming drops of liquid water, known as dew. In general, water molecules attract one another through a type of intermolecular force called hydrogen bonding, which occurs among molecules when hydrogen is bound to a highly electronegative atom such as oxygen. In the case of water, the partial positive hydrogen atom of one water molecule attracts the partial negative oxygen atom of

all images from p hotos . com Weather Folklore

Fact or an adjacent water molecule. Fiction? As the surface of the Earth cools to temper- atures below the dew point, dew forms on the By Brian Rohrig surface of blades of grass and grows, as more he biggest football game weather. As a result, a large body of weather water condenses. For the same reason, you of the year is this Friday folklore was passed down through the ages. can see your breath on a cold morning. The Tnight. Your team has How accurate are these ancient methods? Can water vapor from your warm mouth instantly practiced nonstop for the past six months. anyone become an amateur meteorologist by condenses into the cloud of fog you see when You arrive early and take to the field to warm simply observing the world around us? Let’s you exhale, because the cold air outside can- up. You feel a few drops of rain and look up, find out by examining some of the more com- not hold as much water vapor as the warm air seeing the clouds darken. Then a torrential mon bits of weather lore: inside your mouth. downpour ensues, followed by lightning—a So, what does this have to do with predicting sure game stopper. The weather forecast “When grass is dry at rainfall? Dew only forms on cool nights, when called for clear skies tonight. How could they morning light, look for rain the temperature falls below the dew point. So, be so wrong? dew is not likely to form on warm nights. Anyone can predict the weather. But it’s not before the night. Dew on Warmer nights are usually accompanied by easy to predict it correctly. Weather forecast- the grass, rain won’t come cloud cover. Clouds prevent the Earth’s ther- ing is based on statistical probabilities, so to pass.” mal radiation—radiation emitted by the sur- even the experts will get it wrong sometimes. face of the Earth—from escaping into space. Scientific weather forecasting is relatively Before we examine the truth of this maxim, Think of the clouds as a blanket, keeping the recent. It was developed soon after the inven- let’s look at how dew forms. Air is “saturated” surface of the Earth warm at night. Some of tion of the electric telegraph in 1835, which when it can hold the maximum amount of the heat still radiates into space, but much of enabled weather data to be transmitted quickly water vapor possible. To saturate cold air, it bounces off the cloud layer and goes back over long distances and allowed forecasters to less water vapor is needed than to saturate into the ground. predict what was coming their way. warm air. Clear nights, on the other hand, tend to pro- In the 20th century, with the advent of The dew point is the temperature at which duce lower temperatures, as heat can read- computers and satellites, weather forecasting air can no longer hold all of its water vapor, ily escape into space. And we all know that grew by leaps and bounds. But before then, in which case some of the water vapor starts clouds tend to produce rain. If you have no people had to rely on reading nature’s signs. condensing into liquid water. When air is clouds, you probably won’t get rain. Since the livelihoods of many people were warm, water vapor does not condense as eas- So, this piece of weather folklore is, for the tied to the land, it was important to predict the ily as it does when air is cold. most part, accurate. The presence or absence

14 Chemmatters, OCTOBER 2012 www.acs.org/chemmatters of dew on the grass is a fairly reliable indica- bright. The color of the sun itself seems to ticles in the air, which means the approach of tor of whether it is going to rain that day. change, first to orange and then to red. This high-pressure air and good weather. is because more of the short-wavelength blue Just as the skies tell us what is coming our “Red sky at night, sailor’s and green light are now scattered. Only the way, they can also tell us what has already long-wavelength red light can reach your eyes passed. A red sky in the morning typically delight. Red sky in the directly. means that a high-pressure area has already morning, sailors take So, how does sunlight affect the weather? passed over us, so bad weather may be on the warning.” In addition to light scattering by gases in way. A low-pressure system may be moving the atmosphere, a combination of two other in, bringing rain with it. According to this saying, a factors can be used to predict good or bad This piece of folklore has proven to be red sky in the morning is an weather: the presence of fine particles, called somewhat reliable throughout the ages, but impending sign of bad weather, aerosols, in the air and whether the air has a it should only be used as a rule of thumb, as while a red sky at dusk signals fair high or low pressure. most sunsets and sunrises tend to have at weather. A red sky is caused by the sun Aerosols are composed of dust, least some degree of redness. It is the inten- passing through the thickest part of the moisture, salt, or any particle sity of the redness that may help us predict atmosphere when it is low on the horizon. small enough to stay sus- the weather. But why would a red sky in the morning be pended in the air. These particles different from a red sky at dusk? cause light to be scattered even more, “Flowers smell best just and they essentially filter out all but Light from the sun is composed of before rain” all the colors in the rainbow, which red light.

As mentioned earlier, low pressure usually means bad weather and high pressure tends Weather Folklore to indicate fair weather. So, according to this maxim, the presence of odors should signal rain and should be attributed to low pressure. correspond to different wavelengths of radia- Low pressure is associated with bad Odors are due to gas molecules entering tion. Blue light consists of short wavelengths, weather and high pressure with good weather. our noses. Odors often arise from liquids and red light consists of long wavelengths. Low pressure causes air to move upward, turning to gases through evaporation or from The atmosphere scatters light, but not all which, in turn, produces clouds and precipita- solids turning to gases through a process light equally. As light moves through the tion. In contrast, high-pressure air moves called sublimation. This may not seem too atmosphere, most of the longer wavelengths downward, which suppresses cloud formation surprising, but what may come as a surprise (mostly red, orange, and yellow light) pass and precipitation. At the same time, air con- is that there is a connection between air pres- through, and much of the shorter wavelength taining aerosols is trapped near the surface. sure and the formation of these gases. In light (mostly blue light) is absorbed by the So, a deep red sky at sunset indicates the particular, high pressure keeps gases from gas molecules that make up the atmosphere. presence of a large amount of suspended par- forming. The absorbed blue light is then radiated in different directions and is scattered all around the sky. Any direction you look, some of this scat- tered blue light reaches you. Bernoulli’s Principle Because you see blue light In the 18th century, Swiss scientist Daniel Bernoulli coming from everywhere in the discovered that if the speed of a fluid increases, then pres- sky, the sky looks blue. sure in that fluid simultaneously decreases. Bernoulli’s principle helps As the sun begins to set, light explain how airplanes and birds fly. The mov- must travel farther through the ing air helps create a force, called lift, Low pressure atmosphere before it reaches which allows the wing to rise. your eyes. It passes through 465 kilometers of the low atmo- An airplane wing is sphere when the sun is at the designed so that the top is horizon compared to 17 kilo- curved and the bottom is High speed flat. The faster air on top Wing meters when it is overhead. So, Direction most of the sunlight is reflected has a lower pressure, and of flight and scattered before it reaches the greater pressure on the Low speed your eyes. bottom of the wing pushes

anthony fernande z the plane up. As less sunlight reaches you High pressure directly, the sun appears less

chemmatters, OCTOBER 2012 15 Here is why. With high pressure, more col- lisions of gas molecules occur on the surface True or False? of a liquid or solid, preventing them from escaping as readily into the gas phase. Think Use information from this article to decide whether of high pressure as a lid placed on a pan of the following expressions are true or false: boiling water. The lid hinders the molecules from escaping, making them less likely to 1. The higher the clouds, the better the weather. evaporate. 2. When stars shine clear and bright, we will have a very Low pressure makes it easier for evapora- cold night. tion to occur. For example, if the Earth did not have an atmosphere, smells would be 3. The farther the sight, the nearer the rain. incredibly intense, as there would be no air pressure “holding in” all of the gases. When Answers at: www.acs.org/chemmatters p hotos . com people say they can smell rain coming, they are likely noticing all of the increased odors arising from a low-pressure system, a sure they do not have sweat glands. By licking their result in electrical discharges or shocks. sign of bad weather. fur, they become cooler, because as the water So, when there is low humidity in the air, If bad weather is coming, it will typically be on the fur evaporates, it absorbs heat from cats often lick their fur to remove the static accompanied by wind or unstable air, because their bodies and produces a cooling effect. charge. Based on this observation, the maxim any turbulence creates low pressure. Ber- Cats also lick themselves to reduce static is probably true. noulli’s principle states that moving air exerts electricity in their fur. Cat’s fur has a low elec- If that is the case, how about the popular less pressure than still air (sidebar, p. 15). To tron affinity, meaning it has little attraction groundhog which, according to legend, illustrate Bernoulli’s principle, hold a narrow for electrons and will lose them easily. Any helps us predict six more weeks of winter strip of paper under your bottom lip and blow contact with other objects may cause the cat’s if it sees its shadow? Sorry, Punxsutawney across the top. The paper will quickly rise up fur to lose electrons. This loss of electrons Phil, but there is no scientific evidence to into the air since moving air lowers air pres- creates a positive charge. support your claims of weather prognostica- sure along the top, meaning the air pressure When the cat’s fur—now positively tion. Over the past 114 years, the ground- underneath is greater. This greater pressure charged—is in contact with objects that are hog has seen his shadow 99 times, which underneath lifts the paper upward. If wind is good conductors, such as metal or people, means that Pennsylvanians would rarely see blowing across the landscape, there will be electrons from these conductors flow into the an early spring. But a look at weather data reduced pressure, so more volatile molecules cat. This discharge of electrons causes the cat shows that Groundhog Day predictions are in flowers will vaporize. to get shocked. correct only 39% of the time. While this bit of weather folklore holds true, So, when cats lick themselves, does it Weather prediction is notoriously difficult, it may be too subjective to make reliable pre- signal good weather? There is more static even with all of our advanced technology. dictions. But if you have a sensitive nose, you electricity when humidity is low, and low The atmosphere is always changing, and this will most likely have a heightened sense of the humidity generally signals fair weather. On the inherent instability makes it difficult to predict smells around you before a storm approaches. other hand, high humidity limits static buildup what it will do next. Long-range forecasts are Some people with arthritis claim to be able because moisture on the surface of materials especially hard to get right. The same goes to predict the weather when their arthritis acts makes a good conductor. Because of the slight with interpreting nature’s signs. Nature can up. Others have suggested that low pressure increase in conductivity due to moisture, the give us some good rules of thumb, but no causes inflamed joints to swell, increasing imbalance of positive and negative charges method of predicting the weather will ever be pain. While some scientific studies have sug- that create static electricity are less likely to foolproof—at least so far. gested a link between joint pain and air pres- sure, more research is needed to establish a Selected references definitive link. Everyday Mysteries, The Library of Congress: http://www.loc.gov/rr/scitech/mysteries/weather-sailor.html [accessed Aug 2012]. “If cats lick themselves, Weather Basics, Folklore Weather Forecasting, ESPERE Climate Encyclopaedia: http://espere.mpch-mainz.mpg.de/documents/pdf/03Weather/WeatherBasicsUnit3.pdf it means good weather is [accessed Aug 2012]. on its way.” Wilson, J. SkyWatch: Signs of the Weather, Wilstar.com: http://wilstar.com/skywatch.htm [accessed Aug 2012]. Weather Lore and Proverbs, Canadian Meteorological and Oceanographic Society: Cats are known to be clean animals. But http://www.cmos.ca/weatherlore.html [accessed Aug 2012]. cleanliness is not the only reason cats lick themselves. In hot weather, they Brian Rohrig teaches chemistry at Jonathan Alder High School in Plain City (near Columbus), Ohio. His most

p hotos . com lick their fur to cool off, because recent ChemMatters article, “Tasers,” appeared in the April 2012 issue.

16 Chemmatters, OCTOBER 2012 www.acs.org/chemmatters “Chance Favors the Prepared Mind Great Discoveries in

+ – ccasionally, experimental sci- Chemistry nium cyanate ([NH4] [NCO] ), but he made entists pursuing a well-planned an astonishing discovery instead. The white investigation run into a surprise. A By Gail Kay Haines crystalline substance he expected did not totally unexpected result pops up. appear; his vessel held long, transparent crys- OOops! Does that mean the experiment went tals that looked exactly like crystals of urea. wrong? Maybe, but “Chance favors the pre- This was a huge surprise—almost unbeliev- pared mind,” said the famous chemist, Louis able to Wöhler. The chemicals he used came Pasteur. The following three great discoveries from inorganic sources, but they produced an in chemistry—all involving surprises—were organic product. Appearance is not proof, so made because the scientists involved knew he tried the experiment again, using silver cya- how to look beyond their expectations, run nate (Ag(NCO)) and lead cyanate (Pb(NCO)2). with their results, and make a brilliant leap Same result. He compared the substance he into the future. These three discoveries have made in the laboratory to urea from urine and p hotos . com reshaped the entire field of chemistry. found that the two substances had the same chemical formula (CO(NH2)2). Synthesis of urea could pour concentrated urea off the top. Urea and ammonium cyanate have the same Nineteenth century industrial chemistry! chemical formula but different structures and rea (CO(NH2)2) is a chemical found in No one thought of synthesizing urea from properties. For that reason, they are called iso- Uurine—both human and animal. In the other chemicals. At that time, most chem- mers, a term that describes compounds that early 19th century, most cities had dye- ists believed organic materials, from plants have the same molecular formula but different works—large, smelly factories with buckets and animals, could not be synthesized. They structures (Fig. 1). outside to collect urine from men passing by. thought organic chemicals possessed a living The urine was collected in large vats, which vital force, different from inorganic metals and (a) (b) were used for indigo dyeing. (b) minerals. Only living things could make them, + – Urea could not be bought, but fortunately and the force passed from one to another. [ ] [ ] people were willing to give their urine away. No experiment had ever proved this idea, but After a bucket of stinking waste stood around people believed it. Figure 1. Ammonium cyanate (a) and urea (b) are for a few days, the unwanted parts settled to Friedrich Wöhler, a German medical stu- isomers—they have the same molecular formula the bottom (precipitated), and dye-workers dent, enjoyed chemical experiments more but different structures. than he liked medicine. He experimented at home, and he studied chemistry in his college lodgings, with bangs and bad smells and poor

ations grades in medical courses for which he didn’t study. After graduation, Wöhler headed to Sweden to train with a well-known chemist of his day—Jons Jacob Berzelius. By 1828, Wöhler, 28, had his own labora- tory in Berlin, where he studied urea from his own urine, so he knew that it was made of

long, transparent crystals. One winter day, the shutterstock Crystals of urea, a substance found in urine, were : trades and occu p ACS stock illustrations young chemist heated cyanic acid (HNCO) in synthesized in a laboratory for the first time in ammonia (NH3), expecting to produce ammo- 1828.

chemmatters, OCTOBER 2012 17 Here is one way to accomplish Wöhler’s thing astonishing. Certain uranium ores— The sheer hard work took several years, synthesis: pitchblende, in particular—were four times as but the idea was simple. From 4 tons of active as expected. Pitchblende is a mineral dirt, remove everything that was not radium + - consisting mainly of uranium oxides but also or polonium. In nature, radium appears in [NH4] [NCO] + heat NH3 + HNCO containing small amounts of other elements. CO(NH2)2 amounts as small as 0.14 gram per ton of “This abnormality greatly surprised us,” Marie uranium ore, so there was not much left at the Curie wrote. end—less than the weight of a penny. Marie Wöhler’s synthesis demonstrated that Uranium alone could not produce so much Curie eventually produced one decigram of chemicals originating in the body are just like energy. Were her calculations wrong? Marie radium chloride (RaCl2). chemicals in the laboratory. There is no “vital Curie checked for errors, but her mind leaped As was closer to her goal, the force” to separate them. It took another 15 ahead to a new hypothesis. There had to be an samples gave off a beautiful blue glow, “like to 20 years—science moved slowly in those unknown element hidden inside pitchblende, faint, fairy lights,” she wrote. car- days—for everyone to catch onto the new “endowed,” she wrote, “with a powerful radio- ried some in a pocket, and Marie Curie kept a thinking, but organic chemistry became the activity.” The new element would exist in such study of compounds of carbon, not of living a tiny quantity that no one noticed it before. substances. She guessed one part in a hundred. One in a From fuels to plastics to medicines and million is closer. more, the materials that enrich modern life are Pierre Curie joined her, and they analyzed made from organic molecules derived from a 100-gram sample (about a handful) of organic and inorganic sources. And synthetic pitchblende and measured every fraction urea is still used to dye cloth. for radioactivity. With uranium, thorium, and inactive parts removed, the radioac- Radioactivity and the tive fraction became steadily smaller—but discovery of radium relatively stronger. Another surprise—they aria Sklodowska loved learning, but Myoung women were denied entrance into college in what is now Poland—and was then In their laboratory, Pierre and Marie Curie identified radioactive elements called polonium part of Russia—in the 1880s. She agreed to and radium in samples of a radioactive mineral help send her sister Bronya to medical school known as pitchblende. in France if Bronya returned the favor. She was 24 when she boarded the train to France, bit by her bedside. They ignored the fact that changed her name to Marie, and registered at skin cracked on their fingers and both were the Sorbonne. She graduated first in her class, always tired. They blamed hard work for their with degrees in math and physics. There, in pain and exhaustion—they never thought 1894, she met Pierre Curie, who had already of radiation poisoning. Even 100 years later, developed a method, using quartz under pres- Marie Curie’s notebooks are still radioactive. sure, to measure small currents of electricity. Marie Curie was the first scientist to under- In 1897, Marie Curie investigated uranium’s stand radiation came from inside the atom, unexplained radiation as part of her doctoral itself—a huge contribution to both physics . One year earlier, , a both p hotos : curie museum / ac j c collection and chemistry. Marie and Pierre Curie shared French , discovered that uranium Marie Curie was intrigued by the radiation emitted the 1903 in Physics with Bec- by uranium, which she called radioactivity. emitted invisible rays that shot through querel for their groundbreaking research. air, paper, and other materials. Marie Curie Marie Curie received the 1911 Nobel Prize hypothesized that the emission of rays by ura- realized that they had uncovered not one, in Chemistry for the discovery and isolation nium compounds could be an atomic property but two hidden elements. Marie Curie named of radium and polonium. (Pierre Curie was of the element uranium—something built into the new, invisible elements “polonium” (for killed by a horse-drawn truck.) Her brilliant the very structure of its atoms. She called this Poland) and “radium.” plan to learn about radioactivity led to nuclear radiation, radioactivity. Now, only a few specks remained of the medicines, weapons, and nuclear power One characteristic of this radiation is that original 100-gram sample. These were 300 plants, along with the discovery of all of the it ionizes the air around it, that is, it ejects to 900 times as radioactive as uranium. The actinide elements. electrons from atoms or molecules, result- couple managed to buy several tons of pitch- Radium was once used in self-luminous ing in ions that can be detected. Borrowing blende from Austria, with the uranium already paint and watch faces until its dangers became samples, Marie Curie tested every known removed. Pierre Curie found a nearby shed known. It is still important in cancer treat- chemical element for radioactivity. Only two with a leaky glass roof and no heat, where ments. It is used in solar cells in artificial elements—uranium and thorium—emitted Marie Curie began analyzing her black moun- satellites, in brushes that clean up dust from radiation. Then, Marie Curie uncovered some- tain—bucketful by bucketful. camera lenses and photographic films, and in

18 Chemmatters, OCTOBER 2012 www.acs.org/chemmatters devices that eliminate static electricity in vari- surprise. Large molecules of pure carbon— buckminsterfullerene, after Kroto’s favorite ous machines. Even more important, the entire not graphite, not diamonds, not chains— architect, Richard Buckminster Fuller, the field of nuclear chemistry has evolved from made a huge peak on the spectroscope at 60 inventor of geodesic domes. Could nature Marie and pierre Curie’s groundbreaking work. carbons. Other even-numbered molecules have invented the same shape? showed up, but C60 always predominated. Their 1985 computers could not predict Buckyballs: Soccer Molecules are too tiny to see with a micro- a 60-carbon sphere, so they cut hexagons balls made of carbon scope, so scientists determine their struc- from paper and taped them together. Classic tures from chemical reactions. This molecule graphic design, but the structure wouldn’t arry Kroto, a British college student, just floated around, not reacting at all. That curve. Kroto remembered building a sky Hhad a choice to make. Chemistry or 60-carbon size must be an extremely stable dome for his children, using hexagons plus art? He loved both, and while he earned his shape, they thought. pentagons. Smalley finally pulled a structure ph.D. in spectroscopy—the study of Six-sided figures are common together. what worked was a shape made of electromagnetic radiation emitted for carbon, but the corners 20 hexagonal faces, 12 pentagons, and 60 or absorbed by a given chemi- usually form chemical vertices. cal species—he also studied bonds with other atoms. The chemists asked the mathematics graphic design. To be totally inert, this department if they recognized that particular By 1984, Kroto worked as structure must have no shape, and the answer came back, “what a chemist for 20 years. He corners. It had to be you have, boys, is a soccer ball.” The bucky- specialized in astrochemis- a sphere. They named ball molecule, about 1-nanometer in diame- try—the study of chemical the mysterious molecule ter, is a kind of empty “soccer ball” cage. The reactions in interstellar space. real surprise was that this molecule was not Kroto discovered new structures just a curiosity formed by blasting graphite of carbon—carbon chains float- with lasers, detectable only in tiny quantities, ing among the stars—by studying the but that large quantities of it could be made spectral lines the molecules made through a as well. telescope. But where did they come from? The discovery won Kroto, Curl, and Smalley He speculated that the strange molecules the 1996 . Buckyballs might have formed in the atmosphere of a have already led to the synthesis of a thou- carbon star. Carbon stars are the red ones— sand new materials, with uses as varied as dwarfs or giants—with free carbon in their armor and drug delivery. Ancient buckyballs makeup. But Kroto could not find the evi- found in meteorites have led to research into dence he needed. He was thinking seriously the origins of the Earth. Carbon nanomateri- about a career change into scientific graphic als, in the shape of balls, tubes, and wires, design, when he met Robert Curl at a scien- are the building blocks of nanotechnology. tific meeting. Buckyballs, themselves, are so expensive to Curl and Richard Smalley, at Rice Uni- make, they have rarely been used directly, but versity in Houston, Texas, developed a new they may yet become medicines, catalysts,

kind of laser spectroscopy machine, the pURKISS ANNE-KATRIN conductors of electricity, and new lubricants. Ap2 (app-two), to blast clusters of atoms. (here at the University of Sussex, Different eras and different research, but Exactly what Kroto had been looking for! He United Kingdom) codiscovered an unusual the urge to learn more about the world keeps molecule called a buckyball (inset) that looks like wanted to vaporize graphite and see what a soccer ball and has promising applications in great chemists open to discovery. Opportuni- re-formed. So, he put in a request to use the medicine and electronics. ties are waiting! Ap2 machine to simulate the atmosphere of a Selected referenceS carbon star. Chemical Heritage Foundation, justus von Liebig and Friedrich wöhler: Smalley said no. His laboratory was too http://www.chemheritage.org/discover/online-resources/chemistry-in-history/people. busy. But one year later, Smalley found some [accessed Aug 2012]. time. Curl called Kroto in England. Should the Froman, N. Marie and pierre Curie and the Discovery of polonium and Radium, Nobelprize.org: laboratory assistants run his project or did http://www.nobelprize.org/nobel_prizes/physics/articles/curie/ [accessed Aug 2012]. Kroto, H. w. Autobiography, Nobelprize.org: he want to come? Did he! Days later Kroto http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1996/kroto-autobio.html arrived in Texas. A laboratory crew loaded the [accessed Aug 2012]. machine with graphite, and the three chem- The Discovery of Fullerenes, Chemical Landmarks, American Chemical Society: ists worked together, while Kroto directed. http://www.acs.org/landmarks (under “Chemical Landmarks-Landmarks Directory”) [accessed Aug 2012]. They had barely three weeks. Halim, N. Nanotechnology’s Big Impact, ChemMatters, Oct 2009, p 15. Right away, they found carbon chains, like those in space. “Kroto’s long carbon snakes,” Smalley called them. job complete? Gail Kay Haines is a science writer and book author from Olympia, wash. Her most recent ChemMatters Definitely not, because they also uncovered a article, “Sugar in the Blood Boosts Energy,” appeared in the October 2011 issue.

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