Exploding expertise

How do we decide who to listen to about something chemical?  I have a piece in Slate this week (on the brouhaha around the teenager in Florida and the exploding water bottle), and someone in the comments feed there thought to comment on my expertise:

Jack Stephens

The author is apparently ignorant of chemistry. The active ingredient in toilet bowl cleaner is not hydrochloric acid, it is sodium hydroxide. Aluminum and sodium hydroxide react to form hydrogen gas.

16 Hours Ago

 from slate.com

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Franz Liebkind

Some toilet bowl cleaners (e.g. Lysol's) contain hydrochloric acid in 10-ish percent concentration. It is there to dissolve calcium carbonate deposits (i.e. scale) found in hard water areas. Both HCl and NaOH react with nonbulk Al to produce, among other things, H2 gas. Iirc in the HCl case the reaction should go faster.

Sodium and HCl (or just water!) is much neater and more spectacular. Adolescent pyromaniac curiosity inspired many of us to major in chemistry.

9 Hours Ago

 from slate.com

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Franz Liebkind

P.S. USGS says that the water from the Upper Floridian Aquifer, which supplies most of Polk County and Bartow, is moderately to very hard.

I just finished a new Thesis column for Nature Chemistry about the ways in which chemists can (or cannot) communicate with general audiences about chemistry. Is it possible to have nuanced conversations using the word "chemical" and chemistry, or has the word itself chemical accreted so many toxic associations that it can't be rehabilitated? Can chemists have a role in these conversations by virtue of their expertise? (Short answers: Problably not, probably yes, probably not.)

A session at ScienceOnline2013 earlier this year still has me thinking about the disconnect between how chemists want to talk about their field ("did you know that everything is chemicals? just look at how this works! isn't it cool?") and how people process the information we are so enthusiastically providing ("she is a working mother who probably feeds her kids fast food five nights a week and can't possibly care about her family's nutrition so why should I listen to what she has to say about the molecular structure of NutraSweet™?") Addressing the deficit in science knowledge may not in fact help people assimilate what they need to know make informed decisions about things chemical.

For a society who in many ways is so keen on credentials (or how else do those online diploma mills spammers make money), social science research suggests we don't necessarily consider purely those credentials into our decision when we decide who is an expert in a given field. Dan Kahan and colleagues at the Culture Cognition Project suggest that we assess expertise through the lens of our cultural and social affinities as much (or more) as we do through objective credentials.

So when it comes to deciding who you should believe about aspartame, you believe Dr. X who is an "nutritionist, aspartame victim and single mother of three boys" (her doctorate comes from an unaccredited online school) not Dr. Y who does research on molecular structure and is the mother of two boys and is not an aspartame victim (her doctorate comes from a top accredited school).

As for the Slate commenter, I'm rather fascinated that someone could generalize from you don't know what is in toilet bowl cleaner (is the subtext here that I would be above cleaning my own bathrooms?) to you apparently know no chemistry. Could you imagine that a well-trained scientist would not think to look this up even if she doesn't do bathrooms?  (The police report gives the brand of cleaner, which the manufacturer says contains 20% HCl.  Of course, practically it doesn't matter -- both the acid and the base oxidations of aluminum produce three equivalents of hydrogen gas.)

All natural, locally sourced liquid nitrogen?

Robyn Sue Fisher wants you to know that she would never cook with chemicals not found in nature. Smitten, her ice cream shop in San Francisco’s Hayes Valley, may at moments resemble a high school chemistry lab, but that’s because Fisher uses liquid nitrogen to freeze her product.

Nitrogen is “a natural element,” she notes. “It’s all around us.” [The original lead to this NPR blog post.]

I imagine not a few chemists reading this want Robyn Sue Fisher to know that liquid nitrogen is not found in nature on this planet. I suspect if she posted this photo of a cryogenic nitrogen plant in the ice cream shop, she'd have a hard time convincing her customers that liquid nitrogen was natural.

Her comments beg the question of what constitutes a chemical in the mind of a non-chemist.   If we take IUPAC's Gold Book as the arbiter of the technical definition,  a chemical is a material of "constant composition best characterized by the entities (molecules, formula units, atoms) it is composed of." Everyday language has drifted from the technical.  The Oxford English Dictionary offers this definition for the non-technical speaker: "a distinct compound or substance, especially one which has been artificially prepared or purified."

Most people would agree that in common usage chemical carries the connotation of both artificial and noxious, while chemists attach no such presumptions as to source or toxicity to the term.  Much as chemists wish it were not so, there is a growing language gap, and I think it unlikely we are going to regain the ground lost.  Molecule still comes across as more neutral in tone to a non-chemist.   So we are in a moment where we have people who are aghast at chemicals in their food, and others who are fascinated by molecular gastronomy (and likely some overlap in that population).

In principle, I do like the idea of locally sourced ingredients, maybe I should start my own shop and advertise that I use only locally sourced, artisanally produced liquid nitrogen?

I have to say I was also fascinated with how the NPR post morphed throughout the day in response to the comments on the blog.  By the end of the day the introduction read:

Robyn Sue Fisher's ice cream shop, Smitten, in San Francisco's Hayes Valley, may at moments resemble a high school chemistry lab, but that's because Fisher uses liquid nitrogen to freeze her product. 

Nitrogen is "a natural element," she notes. "It's all around us."

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Andrew Bissette has a good piece about chemophobia on Carmen Drahl's blog Grand CENtral today  (In Defense of Chemophobia) which, along with this post from 2011 by Sciencegeist touch on the language issue.

(H/T to Fran who sent me the link to the original NPR post) 

Doing the math around artificial sweeteners

"The controversy surrounding these products natural, natural-like, or artificially made sugars will likely continue for years to come. We do know that artificial sweeteners increase our threshold for sweet taste, and yes, cause us to crave more sweets. If one “diet” soda leads to another “diet” soda, the “diet” effect is soon lost. " [source, emphasis is mine]

The 12 oz diet soda on my desk has 0 calories (meaning less than 5 calories under the FDA rounding rules).  If I drank ten of them, I might consume 50 calories, at most; in all likelihood, far less.  The diet effect is safe, I think.

I'm thinking about how we evaluate information: what does the BS detector look like for scientists versus non-scientists?

(As an aside, there is no evidence that artificial sweeteners increase the consumption of sweets.)

St. Ignatius' Beans: Strychnine and herbal remedies

Before chemists became adept at synthesizing and purifying single molecules, materia medica relied heavily on plant based materials.  The chemicals in plants are not uniformly innocuous, or safe at any dose, a point I tried to make in this article at Slate a couple of weeks ago.  A case in point:  St. Ignatius' beans.

Last fall, I was digging through a 1903 organic chemistry text (looking for examples of eponyms for this article), when a familiar name caught my eye. What was St. Ignatius doing in a chemistry textbook, an organic one at that?  Jesuits, I could understand (quinine is extracted from cinchona, also called Jesuits' bark), but Ignatius (the founder of the Jesuits) himself?

"Strychnine, C₂₁H₂₂O₂N₂, is found in St. Ignatius' bean..."  What is a violent poison doing in a bean named for Ignatius?  Despite the fact that I was up against an impending writing deadline and had a couple of dozen exams to grade, I had to know.

Faba Sancti Ignatii were first described by an Austrian Jesuit living in the Philippines in the 17th century, George Kamel, S.J. (his description was published in the Philosophical Transactions in 1699 - and yes, I looked up the Latin version).  Later authors speculated the plant was named for Ignatius because of its many medicinal virtues (which they do not list).  At the turn of the last century strychnine was part of the US Pharmacopoeia, prescribed as a stimulant — it was implicated in a early Olympic doping scandal — and for gastric upset; in the Phillipines it was often (more sensibly) the bean was worn on a string around the neck for protection against various diseases. These days it forms the basis for a homeopathic nostrum prescribed for grief and melancholia, particularly when associated with an abundance of tears.

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A version of this post appeared at Quantum Theology.

Chemophobia: The Boy with a Thorn in His Joints

I'm at ScienceOnline2013 where Carmen Drahl and Dr. Rubidium just finished running a terrific session on chemophobia: how can we bridge the gap between "better living through chemistry" and ads for "chemical-free sleep aids." The thrust of the session was not how to convince people chemistry and chemicals are good, but more about how to inject nuance into the public conversation. Chemicals have risks and benefits — and of course, are unavoidable. But we current view chemical as synonymous with toxic, hazardous, unnatural or just plain bad.

What are the roots of this cultural shift? Can understanding these help scientists and writers communicate more clearly and in the end help people not only understand what is in their "stuff" — chemicals, it's all chemicals — but give them tools to work with and make decisions about the materials that make up the world — chemicals. As @docfreeride (ethicist Janet Stemmwedel) noted at another session yesterday, we can agree on facts, and still make different decisions based on them.

Today's New York Times has a perfect example of the various ways chemophobia presents in the Magazine: The Boy with a Thorn in His Joints. The piece chronicles Susannah Meadow's search for an effective treatment for her son's rheumatoid arthritis. She agonizes about the decision to give him methotrexate (which in high doses is used in anticancer treatment) and turns to alternative treatments, in particular four-marvels powder. There are intense arguments with the pediatricians and with her husband over the issue. I was struck by two things in this piece. First, the language Meadows uses to limn the controversy, and second her ignorance, not so much of the chemistry that is in your face (methotrexate), but of the ways in which chemistry is couched in alternative cultural schemes(four-marvels powder).

It makes me wonder how chemophobia is linked to the language we use to talk about it. It can be nearly impossible for an non-chemist to figure out what methotrexate is (beyond "a chemical"). The very name sounds harsh. Four-marvels powder is easy to parse: a powder with four effects. Its name rings with hope.

I also wonder if we worry more about stuff we are familiar with, we've heard more talk on the street about their risks. So we obsess about vaccines, because we hear and read about the side-effects of vaccines, but how many people know anyone who has died of measles? (One of my sister's friends died of measles when I was a child, before there was a vaccine.) So we get in the Times' piece "I was desperate to find a way...without the drugs." pushed up against "[My husband] has always been more comfortable with pharmaceuticals, more trusting in general."

Of course, four-marvel powder is a pharmaceutical, it's just from a different pharmacopoeia — the traditional Chinese — than the one Meadows or her husband is familiar with. Meadows can read the package insert with information on the side-effects of methotrexate, she may be unaware of the routine advice given in Chinese medicine programs (and yes, there are formal academic programs in Chinese medicine, e.g. at Nanyang Technical University) about four-marvels powder (it should never be given to pregnant women, for example, which might make you hesitate before giving it long term to infants or young children).

The session at SciOnline2013 brainstormed about effective ways to help people develop a better sense of nuance around what is a chemical and what are the risks of this particular chemical? What strategies do you think would be most effective?

Will bromine turn squirrels purple?

Most winters Punxatawney Phil is the furry face of Pennsylvania, but last year, he had competition: meet the purple squirrel of Jersey Shore (which should not be confused with either a television show or a town in New Jersey).

The news report offers a number of theories about the squirrel's unique coloration.  A dye job seems the likely culprit, whether from the squirrel's nesting material or an inadvertent bath in a violet solution.  Computer scientist Krish Pillai had a novel suggestion: "This is not good at all. That color looks very much like Tyrian purple. It is a natural organobromide compound seen in molluscs and rarely found in land animals. The squirrel (possibly) has too much bromide in its system."

Leaving aside that Tyrian purple (produced by a particular class of marine snail and to the best of my knowledge and research abilities by no mammal) is a much redder color, this assertion is roughly equivalent to saying that if I eat too much chloride, say from table salt, my body could start synthesizing Splenda, an organochloride.  No, just, no.

Pillai is apparently extrapolating from reports that bromide (bromine anion - Br^-) has been found contaminating wells near fracking sites.  Calcium bromide is used in drilling fluids to increase density, by some estimates 20% of the bromine used in the US ends up in "clear brine fluids" — mixtures of various bromides.  But it is a long way from bromine ions to 6,6′-dibromoindigo along very specific biochemical pathways.  Which squirrels don't have.  Or humans.  (What can and does happen is that the bromide reacts with various chlorine compounds used in water purification to form organohalides, which aren't healthy to ingest....)

It's worth noting that direct ingestion of dyes can have interesting effects on pigmentation.  Flamingos get their characteristic color from ingesting shrimp pigment, and you can change the color of a canary's feathers by feeding it paprika.  Humans who eat too many carrots can develop carotenemia — they turn orange.  These processes are reversible, stop eating the shrimp or carrots and feather or skin return to their normal coloration.  Unfortunately consuming silver or gold can produce a permanent change in skin coloration, as in argyria.

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An alternate definition of a purple squirrel via Urban Dictionary.

Building Skills

Grasping the abstract models chemists use to understand what holds a molecule together — its bonding —  is one of the major goals of the general chemistry course I am teaching this semester.   Understanding the bonding in a molecule is the key to predicting and understanding its structure and reactivity.  The models chemists use to describe bonding in molecules range from what can be done on the back on an envelope, such as  Lewis dot structures or VSEPR structures, and those that require hefty amounts of computer time to set up and solve (ab initio MO theory).  The text we are using includes many full color diagrams of bonds, but student still struggle with how these two dimensional representations "work" in three dimensions.

Ad hoc models — mock ups of molecules built by hand from mundane materials such as cardboard and wire — have a venerable history in chemistry.  Watson and Crick used cutouts of the bases to figure out how they paired along the helix; Smalley built a paper model of pentagons and hexagons to see how C₆₀ could be constructed.

So last week, I brought paper, tape and some simple molecular models (tubes and small metal centers which I buy by the bag to hand out to students) to class and asked students to build a valence bond model for acetaldehyde (implicated in hangovers - acetaldehyde, not valence bond theory, though the latter certainly can make students queasy).  Students cut, paste, built and discussed, producing what you see in the slideshow.

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With thanks to Danqui Luo, Tess McCabe, Kai Wang, Ben Kaufmann and all the students of Chem 103 who built and photographed the models.

Hurricane Chemistry: Renovating Butter

Hurricane Sandy left us without power for several days and while a basement chest freezer remained solidly frozen, thermal equilbrium was unfortunately reached by our refrigerator and kitchen, at roughly 55^oF.  Saturday morning found us rooting through the refrigerator, deciding what had to be chucked (milk) and what didn't (ketchup).  Butter?  In this cool weather, it could stay, it would be unlikely to have turned rancid.

But coincidently, while breezing through a depression era Chemcraft chemistry set instruction book, I encountered directions for "renovating" rancid butter.  Around the same time that margarine made its debut, so did process butter, butter that had been treated to remove the objectionable materials.  As near as I can tell, it's an extraction process, presumably the rancid materials (such as butyric acid) dissolve in the cream and the remaining materials can be reworked into a solid mass.

Laws remain on the books in many places forbidding the sale of process butter without making clear to the consumer what is being purchased.  In the early part of the 20th century this was widespread enough for the US Department of Agriculture to print a booklet which "enable[s] any housekeeper, with only the usual facilities of the kitchen, to distinguish in the great majority of cases between genuine butter, renovated butter, and oleomargarine."

Next time the power goes out, I'll know how to "renovate" my butter, as long as I don't intend to sell it!

Unbending the bends

Sometime before dawn this morning, we took our oldest son to the airport. He's bound for the Caribbean for a pre-orientation trip for college (learning to sail with a team of other freshmen). They will get the chance to do a little snorkeling, but when his dad asked him about whether or not they'd be doing any scuba diving, he replied enigmatically,"There is no hyperbaric chamber in the Virgin Islands. They'd have to fly you to Puerto Rico, I guess."

My first response was to wonder how they would do that, given that most aircraft are pressurized to something around 10,000 to 15,000 feet, which would certainly exacerbate the bends - the outgassing of nitrogen from the blood, which can cause embolisms (blockages) in your blood vessels and painful swelling in your joints.

Henry's law governs the amount of gas dissolved in a liquid: the amount of dissolved gas depends on the external pressure of the gas. For example as the pressure of carbon dixoide increases, so does the amount of dissolved carbon dioxide. Some portion of that dissolved CO₂ turns into carbonic acid (H₂CO₃), and lowers the pH, which gives soda water it's characteristic bite. It also means that acidification of the ocean is a risk of fossil fuel burning, and the resultant carbon dioxide in the atmosphere. Climate deniers will say that there is no data linking CO₂ levels with changes in the ocean pH, suggesting it's because the oceans aren't plain water, and that this will complicate the chemistry. True. But your blood is pretty chemically complicated, and this is essentially the system that is used to control your blood's pH.

So why would flying make the bends worse? As the external pressure of nitrogen falls with altitude, more nitrogren comes out of solution in your blood stream and joints. Neither are places where you want more bubbles. If possible, victims of the bends are evacuated on planes that can be pressurized to lower altitudes (an expensive proposition, and one often not covered by travel insurance).

Bariatric chambers allow the external pressure to be increased, and then slowly decreased to prevent the formation of large bubbles. It can take several "dives" to assuage the symptoms. I sat with my mother while she underwent treatment in a hyperbaric chamber, it's not for those with claustrophobia is all I will say.

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Photo is from Wikimedia.

Red Dwarfs

A version of this was written as a guest post for an artist friend's blog.

If you see a colored compound in chemistry, you can almost bet that it will contain a transition metal. Though we think of metals as being a shiny grey hue (with a few exceptions, gold being one), metals are key elements in producing colors for artist. The visible frequencies of light are relatively low in energy, and conveniently correspond to the small gaps in energy that electrons can leap in metals (what chemists call d to d transitions). Cobalt blue, one of my favorite hues, is (as its name suggests) a cobalt salt: CoAl₂O₄. To get different colors, you have to use different metal salts. You can get a brilliant, though not long-lasting, yellow pigment using lead chromate, the same chrome yellow that Vincent Van Gogh made famous. Tweaking colors to get slightly different hues requires either mixing materials or finding a different salt altogether, the gaps that the electrons leap over when they absorb light aren't adjustable.

But there are other ways to capitalize on the properties of metals to create color. Red stained glass has been made for centuries by adding gold to molten glass and carefully controlling the temperature. The gold clusters together in small particles which then become evenly distributed and suspended in the glass.

These tiny clusters are called nanoparticles, because they are 100 nanometers or less in size. One nanometer is 1 billionth of a meter, the period in this sentence is about a million nanometers across, the little gold balls in red glass are about 25 nanometers in diameter. (The prefix nano, comes from the Greek word for "dwarf," hence the title of this post.)

The gold nanoparticles are not dissolved in the glass, but form a colloid. And one property of colloids is that they scatter light. Different frequencies of light scatter differently, which is why the sky is blue, though the scattering of light by a colloid is a slightly different process. (Scattering isn't the only process involved in the color, but unless you really want to fly off the math cliff with me, let's leave talk of quantum dots and wavefunctions to another day.)

The color of light that a colloid scatters depends on the size and shapes of the particles dispersed. It turns out just by varying the size and shape of the particles involved you can tune your gold nanoparticles to be red, red-violet or even green and many colors in between!

If you are interested in knowing more about the history and chemistry of color, Bright Earth: Art and the Invention of Color by Philip Ball is a terrific introduction. He has a recent blog post about color here. For a readable introduction to nanoparticles, quantum dots and color, try this article in the NY Times.