Have I mentioned lately how awesome chemistry is? It’s pretty freaking awesome. I’ve learned several things this week that absolutely blew my mind, so, naturally, I’m going to share them with you (yay, sharing!).

The first thing has to do with Scotch tape. I don’t usually jump up and down with excitement over my chemistry textbook, but this week’s chapter on spectroscopy and light contained some information that was jump-worthy (to my roommate’s surprise). Apparently, if you peel a roll of Scotch tape in a 1.3µbar vacuum (that’s an enclosed space with very, very low pressure), it actually emits x-rays strong enough to create the image of a finger bone on dental film in a mere second. Electrons sometimes suddenly accelerate as the adhesive strip is separated from its backing creating a visible stream of blue light (1). It only occurs in a vacuum, probably because moisture in the air acts as a short circuit to the movement of electrons in the tape. In addition, different brands of tape give off different spectrums of light. There are all kinds of potential applications for this strange phenomenon from electron-bursts directed at cancer cells to research in nuclear fusion (2). My roommate and I peeled some tape in the dark in our dorm room and freaked out about observed the same glow-in-the-dark-esque light emission that was observed by scientists in 1939. Pretty incredible, if you ask me.

The second thing has to do with apples. Again with the apples, I know. But this doesn’t have anything to do with cider. In the April 8, 2013 edition of Chemical and Engineering News in the Government and Policy section (31-33), there’s an article (“Engineered Apples Near Approval”) about genetically engineered apples that don’t brown. There’s a good chance that these apples will be approved for use in the U.S. because there’s really no reason not to grow them except for a few concerns about very unlikely cross-pollination with other apple trees. The Arctic Granny Smith apples that are being modified by Okanagan Specialty Fruits of British Columbia have simply had a gene inserted that is a duplicate of a gene apples already contain (the one that causes a chemical reaction that results in browning). The duplication causes cells to undergo a natural process that prevents double-genes from appearing. This technique is known as co-suppression, and the gene insertion is performed using a modified bacterium. There are a lot of good reasons to make these apples. Money will be saved for growers, packers, and retailers who won’t have to worry about brown spots on bruised apples. In addition, the consumer will throw away less fruit. The modified Arctic Granny Smith performed just as well as other apples against pests and diseases, so the concerns about proliferating orchards with a more susceptible variety were eradicated. The nutritional value of the apple also improves because the chemical largely responsible for browning, an enzyme called polyphenol oxidase (PPO), breaks down the antioxidants in the apple’s flesh when exposed to air. Without that enzyme, more antioxidants remain intact for consumption. I’m not totally pro-GMO or anything because some of them (like Monsanto’s NewLeaf potatoes that produce their own pesticides) are kind of unnerving from an environmental stand point. I think that making apples that don’t brown is a good use of our understanding of genes. Plus, it’s pretty nifty.

A Gastric-Brooding Frog

Finally, the article right after the one about apples (“Reviving the Dead,” 34) summarizes a TED-talk about de-extinction. With our ever-increasing understanding of genomes, it’s apparently now possible to bring extinct species back into existence. The article says, “The talks were not about mere possibilities. Recent advances in cloning, genetic engineering, stem cell research, and other scientific fields have brought humans much closer to [bringing extinct animals back]. One of the biggest announcements at the conference was the successful creation of a gastric-brooding frog embryo. The frog has been extinct since 1983.” So, basically, now we have to decide whether or not it’s ethical to bring extinct species back that might no longer have habitats. There’s a lot of debate over whether or not it would be right to re-create a species just to keep it locked up zoos or labs. Our bio-technology has advanced more quickly than we’ve been able to repair environments. Also very interesting.

That’s all for today’s post. I hope you find these tidbits as fascinating as I did. Keep reading! Subscribe! I’ll be updating monthly or so from now on : )

-Ashley

Sources:

(1) Harris, Daniel C. “18: Let There Be Light.” Quantitative Chemical Analysis. 8th ed. N.p.: n.p., n.d. 389. Print.

(2) http://www.nytimes.com/2008/10/28/science/28xray.html?_r=0

(3) Bettenhausen, Craig. “Engineered Apples Near Approval.” Chemical and Engineering News   (2013): 31-33. Print.

(4) Heidari, Nader. “Reviving the Dead.” Chemical and Engineering News (2013): 34. Print.

Every year at Sweet Briar College there’s an event called Briar Bowl in which a bunch of teams of nerds students with one faculty member each get together and compete by answering trivia. It’s loads of fun. There’s the opportunity for bragging rights hanging out with friends and faculty. I hope other schools host something similar. The questions are totally random: everything from pop-culture (author of 50 Shades of Gray) to mathematics (if an object is traveling at 5ft/s, how far has it gone in an hour?). The Dean reads the questions, and the students all scribble their answers in a mad flurry. When the science questions come up I get handed the pen whether I have a clue or not.

Once, I actually did know the answer. The particular factoid in question had been drilled into my head over and over ever since pre-biology in seventh grade. Question: What two scientists won the 1962 Nobel Prize for Physiology/Medicine for solving the conundrum of DNA’s structure? Answer: Francis Crick and James Watson (and technically, Maurice Wilkins).

Single Helix

Disclaimer: I’m not a biologist. Recently, I ended up learning a few things about DNA as a result of fellow Sweet Briar student, Samantha Meiser’s research. Before I get into that, I’d like to take a moment to recognize Rosalind Franklin, whose research on the structure of DNA was somewhat undermined by the official winners of the Nobel Prize. Rosalind Franklin took groundbreaking X-ray photographs of DNA molecules which revealed their helical (spiral) structure. Although Franklin had died by the time the award was given, it’s unlikely that her efforts would have been noted anyway, given the attitudes of those who received the prize. Francis Crick once admitted ”I’m afraid we always used to adopt — let’s say, a patronizing attitude towards her” (1). That’s not to say that Crick, Watson, and Wilkins didn’t do valuable research. They did. But so did Franklin. Read this article for more of the story.

Anyway, some research has been done since the ’60′s which reveals that the double helix isn’t the only structure for DNA. What Watson and Crick did was connect the single helix’s from Franklin’s photographs, revealing that the actual structure is a double helix. Here’s a basic run down of this DNA (deoxyribonucleic acid) structure: the “double helix” is two long chains twisted around each other (like a swirling ladder). The chains are made of a few types of molecules, notably nucleotides. Nucleotides in DNA make up nucleic acids which fit together in neat pairs when the helices are fitted together. Below is a video for kids that actually explains it pretty well, and it’s only like two minutes long:

So, just to throw a curve ball at you, there are actually other structures of DNA, like the g-quadruplex (this is what Samantha researched). G-quadruplex DNA is square-shaped, and consists of four of the same nucleotides (four guanines). Recent research has shown that this form of DNA is likely to occur naturally in some cells, and studying it may be valuable in understanding how cancer grows and spreads (2). It is believed that g-quadruplex DNA is important in the process of DNA replication (definitely check that link out). Therefore, if something goes wrong with the g-quadruplex structure, there could be serious negative impacts on the production of healthy DNA molecules (3).

G-Quadruplex Molecule Structure (NOT a double-helix)

I’ve been under the impression that the double helix is the only structure for DNA. One of the reasons I choose to study science is that it’s always changing and advancing. You never know what you might learn to be true or untrue. In organic chemistry, there were numerous occasions in which the best the textbook could do was to say “it is believed that….”

What I’m learning today might be proven totally wrong in the next few years, but that’s okay. Science has to be adaptable and open to new possibilities, possibilities that we haven’t even imagined yet.

Thanks for reading : )

-Ashley

(1) http://www.pbs.org/wgbh/aso/databank/entries/do53dn.html

(2) http://www.scientificamerican.com/article.cfm?id=four-strand-dna-structure-found-cells

(3) http://bioinformatics.oxfordjournals.org/content/25/12/i374.full

Admittedly, Sweet Briar College doesn’t often sell out events or fill its auditorium. I’m pretty sure there are more seats than there are students. When someone as inspirational and respected as Barbara Kingsolver comes to speak, there’s suddenly a wait list. I can’t believe I’d never heard of her before a month or two ago and only then because it was an event I was required to go to for an English class. Kingsolver is a novelist who does research and writes about science-y things in a way that people not only find accessible but also that they can’t get enough of. On Thursday evening, she read from her latest novel, Flight Behavior, and spoke a bit about communication between the sciences and the arts. On Friday morning, Kingsolver was at a two-hour question and answer session, which I’m happy to say was very well attended by students majoring in sciences.

As a well-known author who went to college for science herself, her perspective and interest in bridging the gap between science and writing has added weight. For Flight Behavior, she traveled to Mexico to see the monarch butterflies in person, as well as to research labs to become intimately familiar with the lab atmosphere. For obvious reasons, her interest in having one foot in science and one foot in arts and communication made me super happy, but not as happy as seeing the popularity and enthusiasm of the crowd.

I was immensely impressed by both discussions I attended and yes, I bought the book. Below is the video streamed during her talk and reading in the Sweet Briar College Murchison Lane Auditorium on Thursday evening. Feel free to skip around the footage, but I highly recommend listening to the “talk” portion before the reading.

-Ashley

Even though there aren’t currently Twinkie’s or HoHo’s on the shelves, there are a plethora of other packaged foods that contain unpronounceable ingredients. There’s a lot of debate over whether or not it’s safe to consume these chemicals. Personally, I’d argue that we probably shouldn’t be eating things we can’t pronounce. For now, I’m interested in the chemistry behind why they were added by the food industry in the first place. I can’t cover all of them, but I did some research on a few major players in the world of food acronyms and additives.

Still fresh, even after the apocalypse.

Apparently, metals such as copper and iron are a big problem for the food-producing industry. Trace amounts of metal, often from the water used in production, can have serious consequences on shelf-life. Metals can act as catalysts, which mean they speed up reactions. Transitions metals tend to increase the rates of reactions because they can easily give and take electrons from other molecules, which makes those other molecules more excited to react with each other (because all atoms need the correct number of electrons to be happy). As a result, if you have metal your in food, even in teensy, tiny amounts, the food will decompose faster. This problem is most apparent with things that have lots of water in them, like salad dressings and sauces.

A chemical called EDTA (Ethylenediaminetetraacetic acid) can be added to reduce the effects of metals on shelf-life. The structure of the molecule actually allows it to completely surround a metal atom (chelating), preventing the metal from reacting with the food. It’s like giving someone a big hug: they can’t take out their anger on anyone because they’re stuck but they feel better because their emotional needs are being met (like a molecule with the correct number of electrons is a happy molecule). EDTA is particularly useful for creating lower fat products because these products require a higher percent of water. The more water involved, the greater likelihood that there is metallic contamination (1).

There are other uses of EDTA that make it particularly interesting. For example, it can be used to treat heavy metal poisoning (2). In addition, (for the real chemistry nerds out there) it’s been used in labs to effectively sequester metal ions from solutions.

Some food additives are antioxidants. I’ve mentioned before that antioxidants are good for your body. They essentially slow down the aging process of your cells. Well, the same principle applies to antioxidants in food. The food will age more slowly if it doesn’t oxidize. It’s sort of like putting lemon juice on an apple to keep it from turning brown, except with chemicals that may or may not be safe to consume….

Butylated hydroxyanisole (BHA) and Butylated hydroxytoluene (BHT) are similar chemicals used as preservatives/antioxidants, especially in high-fat foods like potato chips that are likely to go rancid (bleh). BHA has been used in all sorts of contexts, ranging from cosmetics to rubber:

BHA is added to butter, lard, meats, cereals, baked goods, sweets, beer, vegetable oils, potato chips, snack foods, nuts and nut products, dehydrated potatoes, and flavoring agents. It is used in sausage, poultry and meat products, dry mixes for bever- ages and desserts, glazed fruits, chewing gum, active dry yeast, de- foaming agents for beet sugar and yeast, and emulsion stabilizers for shortening (IARC 1986). BHA stabilizes the petroleum wax coatings of food packaging (HSDB 2009) (3).

BHT is used in many of the same products. They are added to fatty foods because they are fat soluble, meaning they dissolve in fat (like how sugar is water soluble, meaning it dissolves in water), because they are stable at high temperatures (i.e. in boiling oil), and because oxygen prefers to react with the hydrocarbons rather than oils. Oxygen is the enemy of packaged food. The more oxygen reacts with additives, the longer the product’s shelf-life. BHA and BHT are diversions.

Tert-butylhydroquinone (TBHQ) is another common antioxidant, often used in conjunction with BHA and/or BHT. The idea behind the use of multiple antioxidants is that they work synergistically, meaning that they are more effective when used together than any of them would be individually (4).

Not all acronym additives are preservatives. MSG (monosodium glutamate) is a well-known food additive with potential side effects that have made many consumers skeptical. MSG was first isolated in 1866, but didn’t become popular as a food additive until 1908, when a Japanese chemist (Kikunae Ikeda) realized that glutamic acid, a component of MSG, had been flavoring soups for centuries. The production of MSG is now a trillion dollar international industry. It became popular because of the potency of its flavor, which is now associated with the term umami (meaning “deliciousness”) because the taste can’t quite be categorized as sweet, sour, salty, pungent, or bitter. It only takes 0.3 grams of MSG to flavor a liter of water (to break the “taste threshold”), whereas 2 grams of salt or 5 grams of sugar per liter are needed before they are detected. Chemical processes occur when MSG is added to some foods, like mushrooms and meats, that cause flavors in those foods that aren’t normally noticeable to become apparent:

MSG also has a strong synergistic effect with disodium inosinate and disodium guanylate, which are found in meat, fish, vegetables, and mushrooms. These substances are almost tasteless in the absence of MSG, but addition of even a small quantity of MSG to food that contains these nucleotides pro- duces an umami that is as much as six or eight fold greater than that to be expected from the quantity of MSG added (5).

Many food additives are meant to increase the stability of a product, while others are strictly to make it taste better. There’s a lot of controversy over whether or not these additives are related to diseases, particularly cancer. MSG is often associated with migraines and “Chinese Restaurant Syndrome.” It’s hard to say what effects these chemicals have on our bodies, but they are effective for the food industry.

Thanks for reading,

-Ashley

Sources:

(1) http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_003c/0901b8038003c0f7.pdf?filepath=versene/pdfs/noreg/113-01322.pdf&fromPage=GetDoc

(2) http://www.umm.edu/altmed/articles/ethylenediaminetetraacetic-acid-000302.htm

(3) http://ntp.niehs.nih.gov/ntp/roc/twelfth/profiles/ButylatedHydroxyanisole.pdf

(4) http://www.inchem.org/documents/jecfa/jecmono/v042je26.htm

(5) http://www.cornellcollege.edu/chemistry/cstrong/512/msg.pdf

History and science have always interested me for the same reason: these subjects explain why things are the way they are. They just explain different types of things. Sometimes they’re more intricately connected than one might expect. Chemistry is connected to many minor historical events, for example the fall of the Roman Empire. Yes!

Lead has the chemical symbol Pb and the atomic number 82 on the Periodic Table. It’s atomic mass is 207.2 and it melts at 621.5°F (327.5°C), which is relatively low for a metal (compared to gold (Au) which melts at 1,948°F (1,064°C)). It’s classified as a heavy metal. Some of the common effects of lead poisoning, many of which are common to all types of heavy metal poisoning, include the appetite loss, abdominal pain, colic, pallor, weight loss, depression, fatigue, irritability, and nervous spasms. Also, eventually you’ll go crazy because it affects the nervous system. It’s not fully understood by what mechanism heavy metals affect the nervous system, but it may have something to do with the enzymes responsible for distributing important minerals throughout the body, such as Calcium and Selenium (1). So, you can see why consuming this type toxin could be disruptive to a society.

Diagram of a Lead Atom

Our love of lead began a long, long time ago. It was one of the easiest metals to work with and extract from natural ore because of its low melting point and abundance in the earth’s crust. The oldest known lead object is from Turkey (circa 6,500 B.C.), and pottery from Ancient Egypt (3,000-4,000 B.C.) has been found glazed with lead. Lead has been used for everything from furniture decorations to stained glass window frames in churches and cathedrals. Its use has had endless repercussions on history, so I’ll touch on the highlights.

Not Sugar!

Lead (II) Acetate, chemical formula Pb(CH₃COO)₂, also known as “sugar of lead” was used by the Ancient Romans as a sweetener for food and beverages, particularly wine (2). That was long before anyone was sailing over to the Americas and bringing back cane sugar. As if running your drinking water through lead pipes wasn’t enough, they went right ahead and added the stuff directly to their diet, sometimes even sprinkling the crystals on dishes like a spice. Good plan.

Lead compounds were also commonplace in colonial times:

During the Colonial Period, in addition to the trade in rum, there was extensive manufacture and use of glazed earthenware, pewter, lead pipe, lead shot, and lead type for printing. Red and white lead were widely used as pigments for paints (also as an addition to red pepper); lead acetate and lead oxide were used to sweeten and whiten bread. Litharge (a PbO product) was used as a putty to install windows and, according to colonial records, was sometimes added to snuff. Apparently, lead intoxication was rampant during the Colonial Period in America and may have been involved in accusations of witchcraft because individuals with lead poisoning neu- ropathy often show weird behavior (3).

Lead Figure of an Ancient Goddess, from Sparta

People long suspected that lead had negative effects on health, based on their observations of those who worked directly with it, such as miners or potters. Yet, time and time again, despite the difficulties of Roman emperors (notably Julius Cesear and his successor, Caesar Augustus) had producing children, the observations of Greek physicians, the warnings of Benjamin Franklin and even the U.S. government, people continued to use it in all sorts of self-destructive ways. In 1473, a publication entitled “On the Poisonous and Noxious Vapors and Fumes of Metals” was authored by U. Ellenberg, but the United States Congress waited until 1970 to pass the Occuptational Health Act to regulate lead in food packaging and the environment.

Benjamin Franklin

I was shocked to learn that leaded fuel was available until the 1990′s, and that a 1980 report from the National Academy of Sciences estimated that Americans were using about 11 pounds of lead per person each year. The General Motors engineers who developed the leaded fuel met the same fate that many exposed to lead had met before,

As many as fifteen workers who helped produce the additive in refineries in Ohio and New Jersey fell sick and died. In most cases, mental derangement preceded death, and many of the workers died in straightjackets. Nearly 300 workers from three plants were pronounced psychotic, and workers and journalists soon began to call leaded fuel “loony gas.” For the next six decades, as many as 5,000 Americans died every year from lead poisoning, according to a 1995 EPA report (4).

I had no idea that lead use was and is such a big deal. Some researchers estimate that 7 million tons of lead from burnt gasoline remain in the United States ecosystem. But, hey, at least we’re not using it as a condiment anymore.

-Ashley

More information about lead and the environment can be found here. And the links in the sources are also worth checking out.

Also, this:

Sources

(1) http://www.ncbi.nlm.nih.gov/pubmed/19644200

(2) http://www.vias.org/genchem/inorgcomp_leadacetate.html

(3) https://kb.osu.edu/dspace/bitstream/handle/1811/23252/V088N3_078.pdf?sequence=1

(4) http://www.dartmouth.edu/~toxmetal/toxic-metals/more-metals/lead-history.html

In or out of love, I think anyone can appreciate the annual Valentine’s Day-induced chocolate craze. I recently learned that this week is officially chocolate week in New York City (makes sense). London also has a chocolate week, from the 8th to 14th of October (does not make sense). But, I mean, it’s chocolate. There doesn’t have to be a holiday or good reason to eat it.

Or does there?

Chemistry says that there is a reason to eat chocolate, or at least reasons we like to.

Chocolate has been claimed to have all kinds of effects on the body and mind, including being a stimulant, relaxant, euphoriant, aphrodisiac, tonic and antidepressant. That’s a pretty impressive resumé. Although there are about 380 compounds in chocolate, only a few have been identified as potential sources of our cravings (5). I always thought that caffeine was the main active compound found in chocolate, but apparently there are other chemicals that play much larger roles in its feel-good properties.

Some of these properties originate from a class of chemicals called methylxanthines. Methylxanthine is what caffeine, theobromine and xanthine are derived from, all of which are found in chocolate. Of the three, theobromine is the big player in chocolate. This study found that the average cocoa powder contains 1.89% theobromine and only 0.21% caffeine. In fact, one variety of cacao plant is actually called Theobroma Cacao (a name derived from Greek meaning, “food of the Gods.” Seems appropriate.). Another study compared how much volunteers’ preferences increased for a mystery drink plus placebo pill, versus a mystery drink plus methylxanthine-containing pill. They found that the drink paired with the chemical was significantly better liked over the course the experiment. The prescence of these compounds must have something to do with our craving for chocolate. So, what exactly is this magical theobromine?

A Theobroma Cacao tree….give thanks.

Theobromine is an alkaloid. Alkaloids are basic compounds that usually contain a Nitrogen atom, and a ring in their structure. They’re often associated with poisonous or addictive things, like nicotine and morphine (because they are also examples of alkaloids) (1). Alkaloids are the reason that dark chocolate tastes a little bitter (see also: black coffee). But, don’t let its alkalinity scare you off.

Like caffeine, theobromine is found in coffee and tea in smaller amounts than in cacao products. In fact, caffeine and theobromine have very similar molecular structures. The only difference is that one molecule (theobromine) has a Hydrogen atom (H), and the other (caffeine) has a methyl group (a Carbon attached to four Hydrogens) on the end (2). Similar molecular structures mean they do some of the same stuff to your brain, like make you more alert (5). Weirdly enough, theobromine lowers blood pressure whereas caffeine actually increases blood pressure (3). So, similar, but not the same. Our brains are very particular (thank goodness).

[Total Side Note: Research is being done to see if theobromine consumption is an effective treatment for asthma symptoms because theobromine is also a cough suppressant (4). I've been wondering since I read that if being sick is an excuse to eat lots of chocolate. Then again, most things are excuses for eating chocolate.]

It’s no coincidence that chocolate is craved by women more than any other food, and the average American eats 11 pounds of the stuff each year (5). This article from CNN health provides some interesting hypotheses about chocolate and mood. A compound called anandamide (a.k.a. the “bliss molecule”) is found in chocolate. It activates some of the same parts of the brain that marijuana does (the part that makes dopamine), but to a much smaller degree. Not only does it contain this chemical, but researchers from the Neuroscience Institute of San Diego suspect that some components of chocolate prevent feel-good anandamide from breaking down in the brain. In addition to speculation about the anandamide content of chocolate, scientists have studied the effects of chocolate on serotonin levels in the brain.

Serotonin is a neurotransmitter, which is any molecule that carries messages through your brain, such as when it’s bedtime or how happy you feel. Specifically, low levels of serotonin can cause depression. One chemical in chocolate (tryptophan) causes the brain to release extra serotonin, which generally results in a better mood. Personally, I’m skeptical that it may just improve my mood because it is delicious.

Finally, chocolate also contains a chemical called phenylethylamine. It’s related to amphetamines.  Phenylethylamine is similar to amphetamines in that consuming it results in lower blood pressure and higher blood-sugar levels. This makes you feel more alert, fine, and dandy.  It also makes you feel like you’re in love as a result of a quickened pulse (5). Just in time for Valentine’s Day <3

It’s been a month since New Year’s, right?

There’s the evidence. As if the taste wasn’t enough……

I hope you enjoyed this post on the chemicals in chocolate : ) Please leave comments or questions, and enjoy some hot cocoa before it’s too warm.

-Ashley

Bonus! A chemistry activity website for your spare time: http://pbskids.org/zoom/games/kitchenchemistry/index.html

Sources

(1) http://www.thefreedictionary.com/alkaloid

(2) http://www.hersheys.com/nutrition-professionals/chocolate/composition/caffeine-theobromine.aspx

(3)http://www.sciencedirect.com/science/article/pii/S0031938411003799

(4) http://www.rsc.org/chemistryworld/podcast/CIIEcompounds/transcripts/theobromine.asp?playpodcastlinkuri=%2Fchemistryworld%2Fpodcast%2FCIIEcompound.asp%3Fcompound%3DTheobromine

(5) http://faculty.washington.edu/chudler/choco.html

Yep. Flu Season. Bleh.

Because food makes you feel better. Not books. Duh.

Everyone’s talking about getting your vitamin C and L-cysteine, but there’s more to a strong immune system than that. Airborne, the dissolvable, fruit-flavored immune-support tablets-in-a-tube contain nearly 2 dozen supplements, from Vitamin A to Zinc. There’s all sorts of weird stuff (herbs, vitamins and minerals) like selenium, echinacea, and riboflavin that scientists and doctors have hypothesized could ease symptoms of an illness, or at least make it shorter. “Herbal Supplements” are plant substances used to treat and prevent illness, “vitamins” are organic chemical substances (substances containing carbon) that plants and animals need for basic functions (growth, reproduction, etc.), and “minerals” are solid inorganic substances (don’t contain carbon) that are needed for muscle control, electrolyte balance and the skeleton.

Zinc is a mineral. It’s a metal made up of zinc. It is made of zinc and only zinc, which means it’s also an element. It’s number 30 on the Periodic Table, and is symbolized by Zn. It’s atomic mass is 65.406 g/mol, which is an average of how much an atom usually weighs if you add up the subatomic particles, like protons and neutrons.

Zinc Atom

But Zinc is so much more than the numbers assigned to it : D

First: a brief history:

Zinc has been used for a really, really long time for a whole lot of reasons. The first known use of zinc was around 20 B.C. by the ancient Romans, who used it in the production of brass (copper + zinc). In 1374, it became the 8th metal known to man- ever after: Gold, 6000BC, Copper, 4200BC, Silver, 4000BC, Lead, 3500BC, Tin, 1750BC, Iron (smelted), 1500BC, and Mercury, 750BC (dates are approximate). The production of zinc metal began in India, spread to China, and made its way to Europe several hundred years later (see: 16th century Germany- a scientist named Georgius Agricola, a.k.a. “the father of mineralogy”). It took a while, but people slowly figured out how to produce pure zinc from zinc oxide ore. The British learned to smelt zinc (1743), the Germans made it even easier to smelt, the French used it to stop corrosion (1836), and the United States figured out how to produce it in 1850. Before 1916, zinc was extracted from ore using very high temperatures (pryometallurgy), but then it was discovered that electrolysis (separation of substances using an electric current) could give greater, purer yields.

And, then we could produce zinc on an industrial scale. In fact, over 11 million tons of zinc are produced every year (converted to my favorite standard measurement, that’s like 2 million elephants). Yay! But, why? You don’t exactly hear people talking about zinc, say, buying a fancy zinc ring or something. About half of all the zinc we make is used for galvanization, a fancy word I could whip out as a kid after hearing my dad talk about submarines corroding (go navy!).

So, metal corrodes, right? That’s a chemical reaction. Steel, which is made out of iron (chemical symbol Fe on the periodic table), tends to rust (rust = corrosion). When iron atoms lose electrons, they become positively charged, and start reacting with things in the environment to become neutral again, because that neutral state is where they’re happiest. Usually, the thing they react with is water with oxygen dissolved in it (i.e. moisture in the air). A new compound, called iron hydroxide, is created. It reacts with water and oxygen again, to create the classic brown rust (hydrated iron oxide).

4Fe(OH)2 + O2 → 2H2O + 2Fe2O3.H2O
Iron hydroxide + oxygen → water + Hydrated iron oxide

And that’s your basic corrosion. It causes lots of familiar problems, like a pedal falling off your bike while you’re riding it because it’s rusted through (not good). Now, back to zinc. Zinc is really good at giving up electrons. It’s so much better at reacting with water that you can actually put a coating of zinc over steel, and the zinc will corrode, but the steel won’t. So, it’s like a sacrifice to the oxygen atoms. This is super useful for metal things in water (especially salt water) and industrial cooling towers (steam + steel = rust). You just have to re-apply the zinc coating when it’s corroded so you don’t get holes in your ship (bad). This process is called galvanization. Very important.

Sulfur-colored Submarine

Other uses of zinc include diecasting, which is basically pressing molten metal into fun shapes, like engine blocks, and creating bronze and brass. More uses? Check out the silly clip below from Kentucky Fried Movie….

I know, none of these things sound even remotely related to your health. Actually, corrosion and nuclear subs, and electric currents all sound kind of bad for your health. However, even though zinc makes up only a tiny, tiny part of the human body (about 0.0032%), it’s a critical nutrient. It’s such a small percentage, but zinc plays an important role in various bodily functions, such as DNA production (and deficiency in a mother can lead to dwarfism in her child). Zinc is also necessary for cell division, protein formation, and wound healing. Zinc also helps your taste buds process different flavors, so a deficiency can cause decreased appetite. White blood cells require zinc during their formation and activation, so people with zinc deficiencies potentially have increased susceptibility to illness. Some studies have even shown evidence that Zinc binds directly to the rhinovirus, and keeps it from replicating, although this result is somewhat controversial. This website has loads of information about zinc and your health : ) Oysters contain more zinc than pretty much anything.

In any case, that’s why your cough drops have zinc in them.

 

I hope you enjoyed this post about Zinc! Stay healthy and warm,

 

-Ashley

 

 

http://ripley.sbc.edu:2680/entry/columency/herbal_medicine

mineral deficiency. (1998). In Mosby’s Emergency Dictionary. Retrieved from http://ripley.sbc.edu:2680/entry/ehsmed/mineral_deficiency

mineral. (2007). In Saunders Comprehensive Veterinary Dictionary. Retrieved from http://ripley.sbc.edu:2680/entry/ehsvetdict/mineral

vitamin. (2008). In The Columbia Encyclopedia. Retrieved from http://ripley.sbc.edu:2680/entry/columency/vitamin

“pyrometallurgy”. Oxford Dictionaries. April 2010. Oxford Dictionaries. April 2010. Oxford University Press. 19 January 2013 <http://oxforddictionaries.com/definition/english/pyrometallurgy>.

http://neon.mems.cmu.edu/cramb/Processing/history.html

http://www.npl.co.uk/upload/pdf/beginners_guide_to_corrosion.pdf

http://www.livescience.com/3505-chemistry-life-human-body.html

Yorifuji, Bunpei. Wonderful Life with the Elements: The Periodic Table Personified. San Francisco: No Starch, 2009. 103. Print.

Now that I’ve had a chance to recuperate from pre-exam stress, exam stress, and post-exam stress, I’m enjoying the holiday season and all that goes with it. A break from school and chemistry courses does not, of course, keep me from doing science-y things. As with any time of year, the holidays are full of cool chemistry that we often take for granted. For example, candy canes. Yes. Candy canes. Now, I’m not personally a fan of exposing my tongue to shards of crystallized sugar, but so many people take the risk that it got me wondering. What’s the benefit? Sure, there’s sugar, the usual culprit that satisfies our sweet toothes. I’ve always been told that chewing gum during a test is beneficial. When I was in high school, my teachers would hand out gum or peppermints as they handed out the tests. Hmmm, I wondered. Does peppermint really help you do better on tests?

Before the Chocolate and Peanut Butter Were Combined

In this post, I want to talk about peppermint, but I also want to talk about being scientific. I happen to study chemistry, but anyone can discover the world through observations, research and simple experiments. I’ve read a number of scientific journals, articles, papers, and reports that reach conclusions based on very methodical, but very, um, interesting (amusing?) tests. The latest one I read was this paper published by the Sense of Smell Institute (about peppermint). They included experiments like having a bunch of people see how many letters they can memorize in a room that smells like peppermint, as compared to how many letters they can memorize in a normal smelling room. Others I’ve read include this one about the efficacy of ginger for nausea prevention, in which volunteers are essentially blindfolded and spun around in a slightly-off kilter chair until they vomit. The funny thing about science and research is that  frequently the only way to figure something out is to come up with a creative way to test it. It’s not all fancy equipment, calculus, and electron microscopes, but more often ingenuity on the part of scientists, and anyone can be a scientist.

Chemical Structure of Menthol, A Major Component of Peppermint

Anyway, back to the red and white striped stuff. Peppermint is one of those plants that’s been used for pretty much everything for pretty much ever. People use the leaves, oils and other products of the plant to treat conditions as common as stomach aches and as complicated as muscle spasms and fevers. It turns out that it actually does most of the things people think it does. The researchers at the above mentioned Sense of Smell Institute compiled a number of studies showing that peppermint does, in fact, have a positive effect on, “enhancing mental performance and cognitive functioning, pain threshold and tolerance, digestion and digestive processes, and athletic performance.” The article is easy to read and well written, so I definitely recommend checking it out (you know, to expose yourself to some bonus science stuff.) Here’s the link again. Research articles aren’t all scary. What chemical compounds are in peppermint that make ingesting or rubbing it on your skin beneficial? For one, peppermint is a stimulant, like caffeine. Stimulants are substances that increase your brain or muscle activity. Stimulants work by tricking your brain into thinking you’re in a sticky situation, like, being attacked by a bear.   They cause your body to breakdown nutrients for energy faster than normal, so you can use the immediate energy to fight back, or run away really fast (see: fight or flight response). This is why caffeine is typically a major ingredient in diet pills – they force your body into an unnatural overdrive.  Substances that we ingest, like coffee, chocolate or peppermint contain compounds with chemical structures that resemble stimulants our brains make naturally, like adrenaline. Stimulants have even been shown to improve physical performanceas a result of the boost they provide. Obviously, there are downfalls of artificially energizing your brain, like headaches, difficulty sleeping, and that increased sense of gravity on your eyelids when you skip the morning joe.

 Remember when I talked about how there are little uniquely-shaped receptors in your nose that match up with little uniquely-shaped smelly molecules? The same thing happens in your brain. Chemicals that are similar enough to ones our brains make regularly produce similar physical effects. It’s like only having raspberry jam when you want strawberry jam. You can make a PB&J with either. So, if you’re directing your focus to, say, a calculus exam while chewing peppermint gum, your brain is being slightly stimulated by compounds in the peppermint that work similarly to adrenaline or caffeine (and I think most college students understand the benefits of caffeine before an exam). Instead solving the dilemma of being attacked by a bear, your extra energy can be committed to answering the next question. Try a peppermint or candy cane before your next test or work out, and see if you notice a difference. Worst case scenario? Fresh breath.

As a bonus, here’s a recipe for candy canes in science-speak (from the American Chemical Society):

-Ashley

Sources: stimulant. (2008). In The Columbia Encyclopedia. Retrieved from http://ripley.sbc.edu:2680/entry/columency/stimulant

http://www.chemistryexplained.com/St-Te/Stimulants.html#b

People are always talking about what foods have the most anti-oxidants. What does that mean, exactly? Perhaps more importantly, does it mean anything? Or, is it just more health-crazed nonsense? As it turns out (this time), it’s not a load of B.S. So, what is it? Surprise! It’s chemistry! Yay!

Sometimes molecules form things called “radicals,” which are molecules with an odd number of electrons (“unpaired electrons”). Usually, atoms have even numbers of electrons (their goal is to have eight (or 4 “pairs”, whether they get them by stealing them from other molecules, or by nicely sharing them). Radicals are not stable. They really, really want to have an even number of electrons. They react with practically anything because of this. In the human body, free radicals form partly because of unavoidable cellular operations, and partly because of environmental toxins. During cellular respiration, which is how our cells convert nutrients to energy, the “superoxide” radical, O₂-, can be formed. Totally normal and natural.

Superoxide, a radical molecule

On the other hand, free radicals can also be formed in less natural ways, such as through cigarette smoke. Chemicals in cigarettes, such as those in tar, react with oxygen as they are inhaled, and create radicals. Substances that create free radicals are one type of carcinogen.

See how the third molecule has only seven electrons?

Too many free radicals is not a good thing. Because they are so reactive, they end up interfering with really important things, like DNA. In cell, a radical might grab a hydrogen off a nearby molecule in the cell as it looks to be more stable. But then, that nearby molecule becomes a radical, looking to steal an electron from something else. It’s like dominos, except the dominos are pieces of your cells, and if enough of them fall over, you have a dead cell. Some scientists believe this is why aging occurs. Or, sometimes you have a cell whose DNA is now damaged, but can still replicate. That’s cancer. Not good.

This is a diagram of the radical reaction, where the O’s represent oxygen atoms, the H’s represent Hydrogen atoms, and the R’s represent groups of atoms with Carbons in them. If you follow the little black dot (that’s the extra electron that makes a radical), you can see that the chain reaction starts all over again when you get to the bottom.

Luckily for our cells, there are antioxidants! And better yet, there’s a fun and easy way to get antioxidants into your body. Eating food! Well, not any food. Many fruits and vegetables (and some nuts) have been found to contain high amounts of anti-oxidants. Some of the most famous ones include Vitamins C and E and beta-carotene. Plus, the body makes a few of its own enzymes that collect free radicals.

So, what exactly are “anti-oxidants,” and what’s so awesome about them that they can potentially help prevent cancer? Anti-oxidants are molecules or enzymes that grab the odd electron from radicals, and neutralize the radical, so they become harmless. These molecules either have an extra electron themselves, or react in such a way that the radical is broken down into a stable molecule. The other way in which anti-oxidants work is by making mitochondria more efficient. Mitochondria are tiny bean-shaped organs inside every cell that play a major part in cellular respiration (making energy). Since they’re so vital to this process, they’re often exposed directly to the free radicals that are made. Poor little mitochondria. The more anti-oxidant rich foods you eat, the more efficiently the mitochondria can produce energy (so, more energy, less radicals). Anti-oxidant rich foods are like force fields for the parts of your cells. Here is a list of some of the most anti-oxidant rich foods.

Keep reading, and keep eating your greens : )

Leave comments if you have questions- I’ll do my best to answer!

-Ashley

Sources:

http://www.rice.edu/~jenky/sports/antiox.html

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/ROS.html

http://www.sciencelearn.org.nz/Contexts/Digestion-Chemistry/Looking-Closer/Mitochondria-cell-powerhouses

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1568603/

http://www.rps.psu.edu/probing/antioxidants.html

It is a truth universally acknowledged….that chemists avoid physics and physicists avoid chemistry. Of course, I’m not saying that scientists are devoted only to their field of expertise and prejudiced against all the others. We’d know a whole lot less about the world if that were the case. I think it’s safe to say that people of all backgrounds like to stick to what they know, whether it’s philosophy or physics.

From: xkcd.com

Unfortunately for scientists, there is an inconvenient amount of overlap between areas of research. This overlap makes communication between biologists, chemists, physicists, etc. absolutely essential. So, in that spirit, let’s venture into the dangerous no-man’s land that is physical chemistry. Physical chemistry (or “p-chem”, if you’re a super hip college student), is, “the branch of chemistry concerned with the interrelation of the chemical and physical properties of matter and the application to chemical systems of the principles of physics (in thermodynamics, kinetics, electricity, spectroscopy, etc.).” Or, in normal-people words, it’s a study of how and why atoms work, and how that knowledge can be used to make things like computers and efficient engines.

I’ve suspected for a while that the physics I’ve been learning is actually chemistry (though the physicists would say that the chemistry I’ve been learning is actually physics). My suspicions were confirmed when I visited the Franklin Institute in Philadelphia, and they had a whole room devoted to explaining electricity. This was really awesome, since we’ve been learning all about electricity in physics class. But I thought that electricity was exclusively physics…..

Yet, lo and behold, there were a number of diagrams…of atoms. As it turns out, electric charges are the result of atomic structure. Atoms are made of positively charged protons, negatively charged electrons, and neutral neutrons. Protons sit in the middle of an atom with the neutrons (composing the nucleus), and the electrons zoom around this dense center, forming an “electron cloud”. Being an electron’s like riding the teacups at Disney World forever, except without tracks and in fast-forward. Atoms are held together by the attraction between the negatively charged electrons, and the positively charged nucleus (just like the opposite poles of magnets stick together). The charge on these particles is inherent, meaning that electrons and protons have charge by virtue of being electrons and protons, just like you’re however old (young?) you are because you’ve lived for that many years.

If an atom loses an electron, it becomes positively charged. If an atom gains an electron, it becomes negatively charged. Atoms don’t lose protons. I’ve always wanted atoms to become more positive because they gain protons, but it just doesn’t work that way. This idea of atomic charges becoming more or less negative applies to whole objects, too. This time of year, everyone starts getting static shocks, because there’s less moisture in the air. Shocks from your sweaters, your car, door knobs, and so forth. The Franklin Institute actually had a sign at the entrance to the electricity exhibit warning people that some of the interactive displays could generate painful shocks. People touched them anyway, of course, and then laughed about it while getting their friends/children/spouses to “learn” about static electricity.

Some atoms want to get rid of an electron, and some want to have more electrons, all in the pursuit of stability. Everything from people to buildings to atoms is happiest when stable. As a result, sometimes atoms let go of their electrons. Sometimes atoms want to get rid of their extra electrons so badly, the electrons actually jump from one material to another. It’s like carrying groceries into your house, and you’re struggling with three heavy bags, but the person who was riding shotgun is bringing the eggs inside. You want to give them one of your bags, and they (assuming they have a conscience) want to take one from you because they feel guilty about not helping. Without ever actually touching each other, you transfer a bag as quickly as possible, hoping no one spills the milk. This is basically what happens when a positively charged material comes near a negatively charged material. The negatively charged material has an excess of electrons, and really, really wants to donate some of those electrons as soon as possible (if only people were so eager to make donations!). This jumping between positively and negatively charged materials is how you can get a shock from a door handle before you actually touch it.

Since we’re on the subject of static electricity (which can be a bit of a bore since there’s really nothing shocking to learn about it), I think it’s worth shifting topics slightly to talk about how electricity is generated in those wind-up flashlights. I learned about this by accident one afternoon while studying in the physics office in the basement of the science building (i.e. my secondary address). My professor was building an experiment on the table I was working at (because that’s what professors do when they’re not teaching class- devise ways to challenge (torture?) student in lab). The experiment involved those flimsy plastic race track pieces and, naturally, a little Hot Wheels car with a magnet attached. It also involved a bunch of copper wires through which the track went, all attached to a multi-meter, which reads how much voltage or current is generated in a current. As it turns out, you can actually create an electric current by passing a magnet quickly through a bunch of wires, which totally blew my mind. So, when you’re cranking the, uh, crank on a wind-up flashlight, you’re pushing a magnet through a coil of wire over and over to generate electricity to light up the bulb. There’s no Hot Wheels car inside the flashlight, although that would be pretty cool….

So, maybe you’re wondering how the heck a magnet running through some wire can create electricity. I certainly was. This method of generating electricity is called induction, and was discovered by Michael Faraday in 1831. We named the Farad after him. Magnets create magnetic fields, which is like the area that’s affected by the magnet, like how the iron filings are affected by the magnet in this picture:

The movement of the magnet and its field creates an electric field in the coil because the magnetic field pushes and pulls electrons (and there are a lot of them in a wire) until a current starts flowing.

Click to Run

The electromagnetic force causes this push and pull, and we wouldn’t have generators in our houses or power plants  (or more importantly, wind-up flash lights) without it.

I’ll stop here, before I get ahead of myself by attempting to cover an entire semester of physics with one blog post.

Did I say physics? I meant chemistry.

Leave comments if you have questions- I know this post got a little technical.

-Ashley

Oh, and a little more Bill Nye before you go:

Sources: Physics for Scientists and Engineers: A Strategic Approach by Randall D. Knight (Volume 4, 3rd Edition)