Weird words of science: scientist

Woman teaching geometry to men
illus. 14th century copy of Euclid's Elements

Scientist may not sound like a weird word, but when it was first coined, it was thought "unpalatable," along with (understandably) "nature-poker." Recently my sister tagged me in a Facebook post linking to a series of articles on women in science. She thought it interesting that the word had been coined to honor the work of a woman in science.

"Not only did Scottish mathematician, science writer, and polymath Mary Fairfax Somerville (December 26, 1780–November 28, 1872) defy the era’s deep-seated bias against women in science, she was the very reason the word “scientist” was coined: When reviewing her seminal second book, On the Connexion of the Physical Sciences, which Somerville wrote at the age of 54, English polymath and Trinity College master William Whewell was so impressed that he thought it rendered the term “men of science” obsolete and warranted a new, more inclusive descriptor to honor Somerville’s contribution to the field." — from Maria Popova and Lisa Congdon's 2013 project The Resurrectionists

Oddly enough, I'd read William Whewell's review of Somerville's On the Connexion of the Physical Sciences while writing an essay about the public conception of scientists, and my recollection was that the coining of scientist, while reported in this review, was not in fact spurred by Somerville's work.  So I went back and read it again.

Whewell was certainly impressed with Somerville and her book, but his tale of the creation of the word 'scientist' makes no mention of honoring Somerville or her contribution.  About the only person Whewell seems impressed with in this context is the "ingenious gentlemen," thought to be himself!

A curious illustration of this result maybe observed in the want of any name by which we can designate the students of the knowledge of the material world collectively. We are informed that this difficulty was felt very oppressively by the members of the British Association for the Advancement of Science, at their meetings at York, Oxford, and Cambridge, in the last three summers. There was no general term by which these gentlemen could describe themselves with reference to their pursuits. Philosophers was felt to be too wide and too lofty a term, and was very properly forbidden them by Mr. Coleridge, both in his capacity of philologer and metaphysician ; savans was rather assuming, besides being French instead of English; some ingenious gentleman proposed that, by analogy with artist, they might form scientist, and added that there could be no scruple in making free with this termination when we have such words as sciolist, economist, and atheist—but this was not generally palatable; others attempted to translate the term by which the members of similar associations in Germany have described themselves, but it was not found easy to discover an English equivalent for natur-forscher. The process of examination which it implies might suggest such undignified compounds as nature-poker, ornature-peeper, for these naturae curiosi; but these were indignantly rejected." [from the Quarterly Review, 1834, emphasis mine]

Interestingly, Wherwell does tackle the issue of women in philosophy/science:  "Our readers cannot have accompanied us so far without repeatedly feeling some admiration rising in their minds, that the work of which we have thus to speak is that of a woman."  It's a fascinating read, in which you can see the threads of imagery that is still current (and still unsupported by data) about the innate differences between the minds of men and women.

And in the end, scientist would catch on, by the early 20th century it was far eclipsed "natural philosopher" as the preferred general term.

From the portals of hell to built-in fire protection: intumescents

A friend posted the link to this demonstration, wondering if it was safe. (Do listen to the children in the background - their cries of "kraken" at 1:02 are worth it.  Science is great fun!)

The caption that came with it noted that it was a mixture of ammonium dichromate ((NH₄)₂Cr₂O₇ )and HgSCN (mercurous thiocyanate).¹ Mercury and chromium, probably not something you want to eat I told my friend. The whole thing made me curious, just what were those tentacles come out of the burning pile? And what chemical reactions were driving it?

It's a coupled set of decomposition reactions. The volcano comes from the decomposition of ammonium dichromate

(NH₄)₂Cr₂O₇(s) → Cr₂O₃(s)+ N₂(g)+ 4H₂O(g)

The reaction produces a lot of heat, which makes the particles being thrown off by the rapid expansion of the two gases (nitrogen and water vapor) glow.

The heat then triggers the decomposition of the mercury compound:

2 Hg(SCN)₂(s) → 2HgS + 4CS₂ + carbon nitrides

The erupting tentacles are an example of intumescence², a property of mercury thiocyanates noted long ago by the venerable Friedrich Wöhler³. It's a well known demonstration, often called Pharaoh's Serpents. Many material intumesce when heated, and thus produce their own insulation.  Some passive fire protection systems rely on this property of polymers, by which they essentially rapidly produce their own insulating layer upon heating, or by swelling up to block air ducts to prevent smoke and other gases from spreading too quickly through a ventilation system.

It works with mercuric thiocynate as well (Hg(SCN)₂) — by some accounts even better — and better yet if you toss a bit of potassium nitrate and a bit of fuel in the form of sugars. In other bits of historical trivia, the mercuric thiocyanate was originally made by the aptly named Otto Hermes. The sale of mercuric Pharaoh's Eggs ceased after some kids ate them with deleterious (fatal) effects.

If you just want to see the snakes minus chromium salts or mercury - try this demonstration based on calcium gluconate instead or check out pyrotechnic expert Tenney Davis suggestions in the Journal of Chemical Education.

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1.  From the Latin verb "to swell" — related to thumb and tuber (as in root vegetables like potatoes)

2.  The chemist who showed in 1828 that compounds made by nature do not have some "vital essence" that distinguishes them from the same structure crafted by a chemist from inorganic (never living) materials.  Something the Food Babe and hawkers of 'bioidentical' hormones do not get.

Read more:

Brian Clegg at Chemistry World.  A paper on the demonstration from Journal of Chemical Education in 1940, by Tenney Davis of MIT who taught courses in explosives way back when ($).

Chemists are wildly polysemous

STO-3G//STO-3G calculated Raman spectrum of arsole

A few months ago this BBC news report - about the evacuation of a building because of a volatile compound got chemists on Twitter talking about language, particularly those words that mean one thing to chemists and something quite different to the rest of the world.  (Thanks @NatalieFey_NLS, ‏@stephengdavey and @stuartcantrill!) Like volatile (high vapor pressure vs. explosive) or to my mind the most overexposed chemical example and the inspiration for far too many t-shirts: mole.  One thing led to another, or at least, one comment by @stuartcantrill led to my Thesis column in  this month's Nature Chemistry.

Is RT retweet or 2.5 kJ/mol?

This piece was pure fun to write.  I enjoyed crowdsourcing examples of chemical double meanings. (List of 200 examples is here.) By far the favorite mechanism of formation for chemists is polysemy, where words share a common ancestor, but the meanings have drifted apart.  Take flush, as in flush a column, or flush a toilet or  flush game or even a straight flush.  All these senses derive from the Latin fluxus for flow.  (Don't see the connection to poker? The OED suggests you think of a flush as a "run" or flow of cards.)

Sometimes the two meanings sit close to the surface for chemists, other times we are pretty blind to the lexical ambiguity.  My youngest son is toying with the idea of a chemistry major, and when I read him examples from the list, he was quick to note both senses for many words: cell, salt, aromatic.  But when I got to molar, he wanted to know what else it meant beyond the concentration of a solution.  "Teeth?" I suggested.  He face palmed.  Whether he majors in chemistry or not, we've already messed with his mind.

Polysemy is productive — as the linguists would say — not just in terms of the language, but of new chemistry.  We ought not to discourage lexical play in chemists (not that one has much control over language in any case, IUPAC's gold book notwithstanding) it gives us a rich set of images to draw on and as I said in the essay, "we can't look for what our language doesn't let us imagine."

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Read the essay here. ($)

Molecular Jek-yls and -hydes

Like Jekyll and Hyde, changing a functional group changes 
a molecule's behavior. Image from Library of Congress.

Chains of pure carbon and hydrogen, called hydrocarbons by chemists, are notoriously hard to get a chemical handle on.  One of the major driving forces in chemical reactions is "opposites attract" — in this case opposite charges.  Since carbon and hydrogen have essentially the same desire for electrons (negative charges), there is not much difference in charge around to drive a reaction. Swap out a hydrogen for something else that does have a relative charge —  chlorine, fluorine, oxygen, nitrogen — and suddenly you have something to react with.  Chemists call these riffs on a basic carbon framework "functional groups" - they are often the parts of a molecule's structure that drive its function.

Change up the functional group, and you change the molecule's behavior. Like Jekyl and Hyde.  Ethanol is something to drink on a Friday night, ethanal is found in the coffee you drink for the hangover the next morning (in an ironic twist, it's also produced as your body metabolized the ethanol.)

The first part of a chemical name tells the size of the carbon framework, the ending tells you about its function — or lack thereof.  Names that end in -yl or -ane mean a hydrocarbon chain without any fancy functionality.  Propane, a popular fuel, is a three carbon hydrocarbon chain.  Methyl mercaptan (added to odorless natural gas to make it smell, and make leaks quickly noticeable), has a one carbon long "chain" in it. Change -yl to -ol and you have made an alcohol, a chain with an -OH group on it (Ethanol is CH₃CH₂OH, sometimes written EtOH, a 2 carbon chain with an OH group on it.)

Knowing the functional groups means knowing something about the kinds of things a molecule can do.  Esters smell floral, carboxylic acids can remove a layer of skin, and are found in many lotions.

So to decode:

-ol means an alcohol (functional group = -OH) but not necessarily the kind of alcohol you drink 

-al means an aldehyde (-COH); these often smell sweetish 

-oxy means an ether (an oxygen sandwiched between two carbon chains) 

-oic acid or -ic acid means a carboxylic acid (pronounced "car-box-sill-ick") salicylic acid, often found in face washes 

-oate means an ester (a COO group sandwich between two chains); ethyl nonanoate smells like grape, the functional group is between a 2 carbon chain (ethyl) and nine carbon chain (nona) 

-one means a ketone, a CO group sandwiched in between two chains

Check out Andy Brunning's of Compound Interest's great graphic on functional groups and their names and Practically Science's map of molecules in food and their smells.

Chemists' Magic Decoder Ring

What if we gave out chemical name
decoders instead of periodic tables?
Vintage magic decoder ring.
Used under CC license. Source.

Earlier this week the Royal Society of Chemistry released a report on the public perceptions of chemistry.  It's a great set of data for those of us who write and talk about chemistry outside of the classroom environment. This infographic sums up the key findings, one of which is that people lack confidence in talking about chemistry.

Stuart Cantrill, chief editor of the journal Nature Chemistry (full disclosure, I contribute regularly to the editorial content of the journal), noted in the discussion which followed the presentation that chemistry uses a very "specific technical language...if you're not talking the same language as someone you are talking to, they can't engage with you...it's almost like a secret language that only chemists know." (Listen here starting at 25:45)

It made me wonder if we should hand out a cheat sheet on how to decode chemical names and functionality instead of the traditional and iconic periodic tables at events. It might make for less splashy t-shirts or shower curtains, but then again, Andy Brunning of Compound Interest makes amazing graphics on all sorts of chemical themes.

Next post:  the secret language of chemists and why butter makes me think of four!

An element by any other name would smell as sweet

Elemental naming was as fraught in the 19th century as it can be today (though now the IUPAC has rules and committees). Alternate names and symbols for elements persisted not merely for decades, but in some cases more than a century.

I've recently skimmed a number of articles about glucinium (Gl). Not familiar? It has 4 protons and these days is known as beryllium for the gemstone beryl, in which it can be found. Beryllium salts can taste sweet, hence glucinium. Beryllium was suggested early on an option, since the sweet taste of its salts was not a unique characteristic. Other metals, including lead and yttrium, form sweet tasting salts. Still, in 1890 many authors were insisting that glucinium was the preferred name, suggesting that the arguments were continuing nearly a century after the initial discovery. It took more than 150 years for the chemistry community to settle on beryllium.

Other elements have endured dueling names, including colombium (now niobium) and the sounds-too-awkward-to-be-real jargonium (hafnium!).

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In searching for an appropriate image, Google turns up lots of bathtubs, including this one. Not only does an antiquated elemental name appear in the description of this wild tub, but the term angstrom as well. Translation software, I'm sure, but what is being (mis)translated?

And I couldn't resist the post title, as one of my fellow Fellows at the Chemical Heritage Foundation is a Shakespeare scholar.

Weird Words of Chemistry: Frigorific

I ran across this word when my youngest, who I'm coaching for the thermodynamics event for Science Olympiad,asked me why the freezing point of water was 32^o on the Fahrenheit scale. The Celsius/centigrade scale was originally pinned to the freezing point and boiling point of pure water at 1 atmosphere of pressure. (Now it's pinned to absolute zero and the triple point of water.) What physical property was 0^o linked to? The freezing point of something other than water? I had to admit I didn't know and now that my curiosity was piqued, went off to hunt it down.

The zero of Fahrenheit's temperature scale was essentially pinned to the temperature of a "frigorific" mixture of ice, water and solid ammonium chloride in a 1:1:1 ratio, along with the freezing point of water and the temperature of the human body. Frigorific seems to have been coined by Robert Boyle to describe particles of cold that were transferred from body to body, and ultimately got attached to mixtures that achieved a particular temperature regardless of the starting temperatures of the materials. Wandering through the old chemistry literature, I found this table of frigorific mixtures "sufficient for all practical and philosophical purposes, in any part of the world in any season," useful in the days before refrigerators, still useful for those who need a constant temperature bath at low temperatures.

The size of a degree was set by bisecting the difference between the point at which ice and water were in equilibrium and body temperature six times, or 64 degrees (2⁶). Binary was easier to use when you had to make your own instrument than decimal.

Frigorific has essentially vanished from the chemist's vocabulary, though it's still apparently alive and well in the engineering literature. As words of science go, it sounds awkward to my ears — as roughly sharp as heaved Arctic ice.

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Nova has an excellent piece on the hunt for absolute zero. Thanks, Kathryn J for the reference!

For more on what I think about well-formed science words, you can read "Neolexia" at Nature Chemistry.

Psychrometry - or how to tell when it's crazy hot out

The heat index is 107 ^oF (42^oC) at the moment. It's hot, and I'm procrastinating going outside by blogging.

My youngest son is doing summer theater, and their rehearsal space is not all air conditioned. So I bought him a cooling towel to help him stay comfortable. When he asked how it worked, I said it was like having a portable swamp cooler — a familiar item as my dad used one for years to cool his house.

The basic principle at work is that it takes energy to make water evaporate. Unless the relative humidity is 100% (in other words, the air has all the water it can hold), water will evaporate. If you keep running air past a wet surface (think a fan blowing past a damp towel, or the breeze blowing over your sweaty face), water will continue to evaporate as drier air is constantly being replenished. The energy to turn the water from a liquid into a gas has to come from somewhere, in this case, the surrounding air and the water itself. The air gets cooler. Whew!

The towel works similarly, there is a very large damp surface area (why the fancy $15 towel really does works better than a damp cotton lawn handkerchief, a much higher surface area than the smooth cotton weave) and as you move around, air moves past. The water evaporates, pulling energy from the water in the towel and makes it colder.

To get a sense of how much energy that is, it takes about 34,000 J to evaporate 15 grams of water (about a tablespoon). 34,000 J is roughly 8 nutritional calories. If you pulled all that energy out of a cup of water, the cup of water would cool off to about 41^o F. (In practice, you don't get things this cool!)

This whole endeavor depends on the air being able to soak up some water, so if the humidity is too high, you are going to be crazy hot towel or no. Swamp coolers work great in desert areas (where my dad lives, for example), and are pretty much useless in New Orleans.

So how cool can you get? To figure it out you need the dry bulb temperature and the wet bulb temperature of the air. The dry bulb temp is just the temperature of the air measured in the usual way (being careful to keep the thermometer out of the sun). The web bulb temperature is obtained by blowing air over a thermometer whose bulb is fitted with a tiny damp sock. For that you can use a sling psychrometer (see the video).

Too hot to be slinging thermometers around? Look up the dew point (your favorite weather app will likely have it) and you can estimate the wet bulb temp this way:

1. Subtract the dew point from the ambient temperature (what your regular thermometer reads)
2. Divide what you get in step 1 by 3.
3. Subtract the result in step 2 from the ambient temperature.

Right now the thermometer outside my window reads 100^o F, the National Weather Service says the dew point is 70^o F, so I take 100-70=30; 30/3 = 10; so the approximate wet bulb temperature is 100-10 or 90^o F.

Once you've got the wet bulb temp you can figure out just how much cooling you can get with a fan and a damp towel!

1. Subtract the wet bulb temp from the ambient temp (the dry bulb temperature)
2. Multiply the difference by 0.8 (assuming the process is about 80% efficient, which is a pretty reasonable estimate)

My calculations suggest that the best I could do to produce cool air in my study this afternoon would be 80% of *100-90) or 8 degrees of cooling. 100^o F or 92^o F? Both are way too hot...I think it's time to stop writing for the day and head for the pool!!

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There are more sophisticated ways to do this, talk to the meteorologists if you want to know more.

Psychrometry comes from the Greek for cold ("psuchron") and should not be confused with anything psychiatric (unless you are talking about mad dogs and Englishmen...)

Unfortunate Acronyms: PUS

When I was lecturing on lasers this week, I was surprised to discover how many of my students were unaware that laser was an acronym (Light Amplification by Stimulated Emission of Radiation). Science is replete with acronyms - Ira Levine once essayed that if you knew enough acronyms you could pretend you knew computational chemistry - good, bad, really funny and occasionally unfortunate.

On my desk is a paper which refers (with as near as I can tell with a straight face) to "PUS research." Public Understanding of Science. I swear this is true.

If you've got a favorite one - funny, famous or truly unfortunate - leave it in the comments for all of us to enjoy...

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Related Posts
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Weird Words of Science: Azote

I was playing Scrabble online the other day and when a z materialized on my rack near the end of the game was desperate enough to try "azo". Good news, what I thought was chemist's shorthand, the dictionary thinks is a word. "Azo" has been part of my vocabulary since I was very young. My dad's graduate work was on azides - molecules that contain three linked nitrogen atoms (N₃) tagged at the end and that are notoriously unstable (a fancy chemistry term for "could explode at any time" - at a dinner for his PhD adviser some 25 years later the number of people around the table lacking fingers was astounding). Azo compounds are molecular relatives of the azides - molecules that have an two linked nitrogens in the middle (R-N=N-R). Some azo compounds are brightly colored and generally they are more stable than azides.

As a rule of thumb, if you see "azo" in a compound's name, it's likely to have nitrogen in it somewhere. Why? French chemist Lavoisier dubbed the fraction of air that cannot support life "azote" from the Greek azotos: without + life. We now know that roughly 80% of the air we breathe is nitrogen gas - hence the connection between azo and nitrogen.

Lavoisier's alternate terms was "mephitic air" -- another Greek import, this time from the name of the goddess who prevented noxious smells from arising from sewers: Mephitis. Ironically, while many nitrogen compounds smell awful (dead fish anyone?), nitrogen gas, Lavoisier's mephitic air, is odorless. That goddess has lent her name to smellier pursuits though - the striped skunk's Latin name is Mephitis mephitis. I can personally attest to the smell.

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Photo used under Creative Commons license. Credit to Kevin Bowman.

Weird Words of Science: Hypsometer

Every time I write an exam, I think about this story, where a physics professor asks on an exam how to measure the height of a building using a barometer. A student answered that he would tie a string to the barometer, lower it down, then measure the length of the string. Given no credit, he protests, and the professor offers him a second chance to provide an answer that is both correct and demonstrates some knowledge of physics taught in the course. The student goes on to give several answers (in some versions the student is averred to be Niels Bohr - though the origin of the story is apparently in a textbook on the teaching of math and science by Alexander Calandra, and unrelated to Bohr) all demonstrating a knowledge of physics, and none the one he seems to know the professor is fishing for (which has to do with the - probably unmeasurably small - pressure differential between the ground and the top of the building).

Here is a chemistry exam question I sometimes ask - how would you measure the height of a mountain with a thermometer? This is a well-known technique,not a trick question, the apparatus is called a hypsometer, from the Greek for "height-measure". The underlying science is that the boiling point of a liquid changes in a known way with altitude. Hypsometers were used before portable aneroid barometers became widely available, and were used in high altitude balloon measurements of pressure as late as the 1960s.

Bonus question: Is it easier to drink a liquid using a straw at the top of Mt. Everest or on the beach in Florida? (Disregard temperature differences and explain your answer for full credit!)

Nano-meter

The Nano Song from nanomonster on Vimeo.

This song certainly has rhythm as well as meter...and does give you a sense of what "nano" means. My non-musical attempt of a couple of years ago is not so jazzy!

Weird Words of Science: Lemniscate Elemental Landscapes

In reading an older paper about periodic tables, the author referred to the "lemniscate table of Gooch and Walker" - but didn't provide a figure, and I had to admit lemniscate was an unfamiliar descriptor. (It's not in the abridged Oxford English Dictionary on my iPod, either - so I don't feel all that ignorant!) Even a Google search was not particularly enlightening.

The full OED came to the rescue - "ribbon like", from the Latin for a ribbon. The term dates to the 17th century when Bernoulli used it to describe a set of curves. The term was new, the curves were not - Bernoulli's lemniscate was a special case of a set already described by Cassini.

Once I located a figure of Gooch and Walker's table, I would agree "ribbon-like" is a good description and it is certainly reminiscent of Cassini's figure eight curves (to give credit where credit is due).

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Figure of the periodic table from Outlines of inorganic chemistry‎ by Frank Austin Gooch, Claude Frederic Walker, Macmillan:New York, 1905. Figure of Bernoulli's lemniscate is from here.

It's Just a Phase

Video Recaps | Full Episodes | Webisodes

Allotropes are all the rage? Or at least sending Conan O'Brien over a very funny edge! The bit was inspired by this article in the NY Times science section. I'm not nearly this riveting when I lecture about allotropes, I've got to admit.

O'Brien gets the chemistry nearly right. My only quibble would be that he calls the different forms (the diagrams are the real thing, by the way) different phases, which they aren't really. They are technically allotropes, different structural forms within the same phase or state of matter. The quintessential example is the allotropes of solid carbon, graphite and diamond and a few others. All that said, when you draw a phase diagram for an element, you show the allotropes on it, and many chemists would characterize the change from one allotrope to another as a phase change.

Oxygen has some fascinating solid allotropes, including one that is a blue solid at room temperature!

Weird Words of Science: isotope

The periodic table is the map of the chemical world. Columns collect atoms which share properties - all of the elements on the far right - He, Ne, Ar… - are all gases and all nearly chemically inert. The region at the bottom harbors elements more likely to be radioactive. Metals pool in the middle.

Each atom of an element has a characteristic number of protons - positively charged particles - in their nucleus. An atom with five protons is boron. One with 82? Lead.

Most atoms also have a number of uncharged particles - neutrons - in their nuclei as well. The sum of the number of protons and neutrons in a given nucleus is called its mass number. A boron atom with six neutrons has a mass number of 11: five protons and six neutrons. Take away a neutron and it’s still boron, but the mass number is now 10.

Atoms with different mass numbers but the same number of protons are termed isotopes. Most elements have several naturally occuring isotopes. The most abundant form of the element carbon has a mass number of 12. One percent of carbon atoms, however, have an extra neutron and a mass number of 13.

Scottish novelist and physician Margaret Todd coined the term for her distant relative Frederick Soddy at a dinner party in 1913. He had described his research to her and she responded that any good discovery need a Greek term to describe it. She suggested combining the Greek “iso” for same and “topos” for place - to emphasize that the mass number of an element doesn’t affect it’s place in the periodic table: argon-36 and argon-40 are both inert gases. Soddy went on to win the Nobel Prize in 1921 for his discovery - perhaps because his distant relation had coined him a such good term?

Allotropes and architects: buckminsterfullerene

Responding to an earlier post on inert gases, a commenter wondered if buckminsterfullerene might act as an inhalation anesthetic - given that, like xenon, it's a large, polarizable ball of electron density. It might, if you could get enough to inhale. At room temperature, the vapor pressure is 5 x 10^-6 torr. Very roughly, that's about a billionth of atmospheric pressure. For comparison's sake, the pressure of xenon necessary to induce anesthesia is about 500 torr, or 65% of normal atmospheric pressure. If you want higher pressures, you need higher temperatures: buckminsterfullerene sublimes (goes directly from the solid to the gas phase, like dry ice) just above 1000F. Not great to breathe...

While likely impractical as an anesthetic, buckminsterfullerene has asthetic properties. It's a highly symmetric molecule - having iscosohedral symmetry. Kroto and Smalley discovered the new allotrope of carbon, C₆₀, in vaporized graphite and named it for the architect (Buckminster Fuller) who made famous the geodesic domes it resembled. Two more familiar allotropes of carbon are graphite and diamond.

Allotropes are differing forms of the same element. The roots of the word are Greek - allos for different and tropos for "turn of mind". A different turn of mind? It's what Smalley needed to propose the now iconic structure, over a beer at his kitchen table.

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Another allotrope of carbon is lonsdaleite - named for Kathleen Lonsdale, an Irish crystallographer who determined the structure of benzene and my brother-in-law's godmother.

Hydrazine: Hype or Hypergol?

Last week the US government announced that it believes it has successfully breached the fuel tank on a dead satellite, effectively destroying the toxic fuel stored on board: 1000 pounds of hydrazine. Hydrazine is a simple nitrogen compound, two NH₂ groups joined by a NN single bond. How does such a simple compound power a rocket?

Hydrazine is a hypergolic propellant - one that ignites as soon as it comes into contact with an oxidant (something that will react with it to effectively strip away some electrons from the reactant and force the molecule to bond differently, the changes in the bonds between atoms are what release the energy). Hypergolic is apparently a term coined by the German rocket program from hyper (very) + ergon (Greek for work) + ol (from oleum, the Latin for oil). Hydrazine is that, a liquid (if not particularly oily one) that can be used to push satellites around in orbit - to do work.

Hydrazine is a solid in the satellite's tanks, and once thawed can be catalytically and rapidly decomposed. Almost any metal will do, though iridium is the usual choice. The reactions produce lots of very hot gases, which you can direct through a thruster:

3 N₂H₄ → 4 NH₃ + N₂
N₂H₄ → N₂ + 2 H₂
NH₃ + N₂H₄ → 3 N₂ + 8 H₂

A little thermochemistry can quickly tell you just how much energy you might produce from 1000 pounds of hydrazine. The overall reaction is:

5 N₂H₄ → 5 N₂ + 10 H₂

which releases 50,000 Joules of energy per mole of hydrazine. A mole of hydrazine weighs about 32 grams, so you get enough energy to make a cold cup of coffee hot from just over an ounce of hydrazine (do NOT try this at home!). If all the hydrazine in that satellite went up at once, it would release about 8 billion Joules (enough to keep the average US citizen in energy for more than a week).

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A photo of a standard satellite thruster.

Repackaging Vitamins: Niacin

Vitamins are small molecules (where small is relative to proteins!) that a living organism cannot synthesize, but are nevertheless required. The word vitamin was coined by a Polish biochemist, Kazimierz Funk by sandwiching together "vital" and "amine". Not all vitamins turned out to be amines (molecules with an NH₂ group in them), however the name stuck.

One such non-amine "vital amine" has the structure shown below. It's a carboxylic acid (the COOH group). Originally designated as vitamin PP, it is now better known as the third of the B vitamin complex or B₃. PP stood for pellagra preventing factor. Pellagra is a nutritional deficiency, once common in Italy, that results in rough skin - pella is Italian for skin.

The original common chemical name for B₃ was nicotinic acid. (The synthetic form can be made by oxidizing nicotine with nitric acid.) In the late 1930s, niacin (NIcotinic ACid vitamIN) was adopted as the preferred name, to avoid confusion with nicotine. (I'm unclear why this was undesirable; smoking was pervasive.)

Repackaging scientific terms to make them less frightening for the general public is not just a historical phenomenon. Much more recently the application of NMR (nuclear magnet resonance) to medical imaging saw its "nuclear" dropped (thus forestalling any potential association with nuclear radiation) to become MRI (magnetic resonance imaging). It should be made clear, that like nicotinic acid, which contains no nicotine, NMR does not require nuclear radiation.

Weird Words of Science: calcium

The isolation of metallic calcium was reported by Humphrey Davy 200 years ago this year. The name comes from the Latin for lime: calx. Compounds of calcium are like duct tape – they hold lots of stuff together. Calcium carbonate keeps clams covered, calcium oxide (lime) is the mortar that held the Roman Colliseum together, and calcium sulfate (plaster of Paris) has been holding broken bones in place for more than a millennium. Calcium keeps us from being a puddle on the floor as well. More than 90% of the body's calcium stores are in the bones.

Weird Words of Science: nonillion

“Do you know what a nonillion is?” queried my mathematician spouse as he plopped into the chair in front of our household computer, “Is it Latin or something?” “Something to do with nine I’m sure,” I offered from the sofa. “That’s OK, I can google it.” What’s the urgency I wonder? 1 vs. 100 is the issue. The mob won.

So what is a nonillion and does it have anything to do with nine? The short answers are: it depends and yes. Nonillion is a novelty number - a term I just coined for numbers that have names, but no uses. Like a googol. The early British usage of nonillion was for 10⁵⁴ - nine million millions. Americans used nonillion for 10³⁰ or 10^3+3x9. In other words, the result of multiplying a thousand (10³) by a thousand nine times.

The system of counting by thousands is sometimes called the “short scale” (from the French term echelle courte). The long scale (echelle longue) counts by millions. Most English speaking countries (both the US and UK included) use the short scale, while most of the rest of the world uses a version of the long scale.

It’s hard to get a sense of scale with these enormous numbers, but a nonillion (long scale) is (very) roughly the order of magnitude of the mass of the universe in kilograms. There are roughly 5 nonillion bacteria (short scale) on earth.

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Literary trivia: e.e. cummings used nonillion in the Enormous Room and in at least one poem.