Field of Science
Tricksy solicitation callers11 hours ago in The Phytophactor
Science books for 14-year-olds1 day ago in The Curious Wavefunction
Metereca4 days ago in Variety of Life
A Parasitic Eel?4 days ago in Catalogue of Organisms
Bioplastic from weaver's broom5 days ago in Doc Madhattan
An aspirin a day keeps the grim reaper away1 week ago in Genomics, Medicine, and Pseudoscience
How do non-competence genes respond to competence inducting treatment?3 weeks ago in RRResearch
And with that I'll take both good and bad questions...3 weeks ago in Pleiotropy
Why I'm Marching for Science4 weeks ago in Angry by Choice
Will democracy survive climate change? - A lesson from the past2 months ago in History of Geology
You can win the Electoral College with 22% of the vote5 months ago in PLEKTIX
Implications of Charles law in a biological matrix: farts8 months ago in The Culture of Chemistry
Harnessing innate immunity to cure HIV9 months ago in Rule of 6ix
WE MOVED!9 months ago in Games with Words
Bryophytes Outdoors11 months ago in Moss Plants and More
If You Are Against Nuclear Power1 year ago in The Astronomist
FieldNotes: water on Mars, less in California.1 year ago in Field Notes
A New Wave of Science Blogging?2 years ago in Labs
Update: Tree of Eukaryotes (parasitology edition)2 years ago in Skeptic Wonder
post doc job opportunity on ribosome biochemistry!2 years ago in Protein Evolution and Other Musings
Growing the kidney: re-blogged from Science Bitez2 years ago in The View from a Microbiologist
Blogging Microbes- Communicating Microbiology to Netizens2 years ago in Memoirs of a Defective Brain
Out of Office3 years ago in inkfish
The Molecular Circus4 years ago in A is for Aspirin
The Lure of the Obscure? Guest Post by Frank Stahl4 years ago in Sex, Genes & Evolution
Girlybits 101, now with fewer scary parts!5 years ago in C6-H12-O6
Lab Rat Moving House5 years ago in Life of a Lab Rat
Goodbye FoS, thanks for all the laughs5 years ago in Disease Prone
JAPAN'S RADIOACTIVE OCEAN | DEEP BLUE HOME6 years ago in The Greenhouse
Slideshow of NASA's Stardust-NExT Mission Comet Tempel 1 Flyby6 years ago in The Large Picture Blog
in The Biology Files
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...
Science in the kitchen: Jello lasers
Romancing the stone (steampunk lit and lasers)
I am in the midst of writing an essay for Nature Chemistry - about why people are so curious about stereotypes of scientists, but seem less so about other fields. There is the DAST (draw a scientist test), but not as far as I can discover similar instruments to assess the images of other professions. Where are the DATTs (draw a teacher test) and DACTs (draw a chef test)? On the other end of the cultural spectrum there is the Big Bang Theory.
The earliest anthropological study I can find dates to the late 1950s and is by Margaret Mead (yes, that Margaret Mead) and Rhoda Metraux under the auspices of the AAAS. They analyzed thousands of essays, drawn from a set of 35,000 written by US high school students. The 1 page essays were written in response to one of three prompts. Prompt I read "When I think about a scientist, I think of..."
What took my breath away was Prompt II (italics are not mine, but as given in Mead's original paper - Science 126, 384-390 (1957)):
If you are a boy, complete the following statement in your own words.Math Man points out that I did both.
If I were going to be a scientist, I should like to be the kind of scientist who...
If you are a girl, you may complete either the sentence above or this one:
If I were going to marry a scientist, I should like to marry the kind of scientist who..."
UPDATE: So there is a draw-a-teacher test (DATt) (H/T to Neil who commented on drawing God - another area that has been explored by educators and psychologists)
Images are from K.D. Finson, J.B. Beaver, B.L. Cramond, "Development and Field Test of a Checklist for the Draw-A-Scientist Test" School Science and Mathematics 95, p. 195 (1995).
If you're looking for the answers - they are here.
After I won a Nobel Prize I suddenly turned into an omniscient sage, whereas formerly I was simply a workaholic.
Richard Ernst, Chemistry 1991
(H/T to Nature Chemistry's October editorial)
Photo of Dirac's Nobel Medal is from: rubberpaw at Flickr
I drive my kids crazy when I critique dramas based on their science content. Listen to the science consultant for Watchmen (Physicist James Kakalio of University of Minnesota) talk about the quantum mechanical underpinnings of Dr. Manhattan's powers.
Stephen Davey, associate editor for Nature Chemistry, blogged at the Sceptical Chymist about visiting the National Archives and seeing the Declaration of Independence, the Constitution and the Bill of Rights. He was surprised to find that the documents were stored under helium as opposed to argon - and wondered why. That started me wondering as well, particularly since the inert gases are not interchangeable in all circumstances (you can use helium to dilute the air mixture for diving, but not argon, for example.)
Helium is both more expensive (not an issue in this context, the cost of the gas inside the cases has got to be the least expensive piece!) and difficult to work with than argon. It can leak out through materials that seem air and water "tight". That's why those latex balloons that looked so cheery on the day of the party are withered and droopy by the morning. They're waterproof, but not helium proof.
In the 1950s the US National Bureau of Standards (now NIST) was charged with deciding on the best way to preserve the Charters of Freedom (the three founding documents of the United States of America). (You can read the full report here.) Helium was chosen, despite its propensity to leak through many materials, partly because a high purity, local source was readily available but most because of its thermal conductivity.
The designers of the encasements wanted a way to measure the pressure of the helium within the cases without having to open them, or remove a sample. Since the thermal conductivity of helium is very different than that of air, changes in the thermal conductivity (how heat moves between the panes) could be used to detect leaks. Argon's thermal conductivity is similar to air, so if argon leaked out and air in, the change would be hard to detect.
New casements were designed about ten years ago, with argon as the gas of choice this time. Sapphire ports are embedded to allow the atmosphere inside the cases to be monitored spectroscopically - by passing a beam of light through the port. Since the new methods of monitoring don't require the inert atmosphere to have a different thermal conductivity, it allows argon - which can't wiggle its way out the way helium can - to be used.
The photo is from The Science News-Letter, vol. 62 (Dec. 6 1952), p. 359.
I am at the ACS meeting in Washington DC, here as "press" rather than chemist. It's a very different way to see the meeting. I went to a press briefing this morning - on the first phases of development of aresol vaccines for measles (Robert Sievers). The press center is tucked away next to the registration, and has everything a writer might want: food, wireless access and a steady stream of caffeine and conversation.
The briefings are being streamed live on the web and journalists watching can send their questions in to be asked. Miss something the first time round? Watch the replay here.
Listening as a scientist to a talk, and as a writer to the briefing turn out to be slightly different experiences. Both require critical listening, but listening as a writer prompts me to think far more about the words the science is coming wrapped in. The shorthand scientists use sounds almost staccato in this context. "Measles naive" instead of "never exposed to the measles virus" or "no evidence of viremia" instead of "no measurable virus in the bloodstream".
We try to be both precise and concise, but I wonder how often the combination in giving a talk, or even reading a paper in the literature leads to attentional processing deficits? An interesting experiment in attentional processing is to present subjects with a rapidly changing sequences of letter, interspersed with numbers. If two numbers are placed too close together, subjects can "miss" the second letter while their brain is busy processing the first. Pack too much into a sentence, and your "subjects" might miss bits.
My Thesis column in Nature Chemistry this month, Stretching Toplogy, takes a slightly different tack in thinking about the ways words wrap around science.
My youngest and I are heading into Philadelphia tonight for a chocolate dessert feast, so it seems apt that a friend sent me this bit of mathematical magic this morning - with a plea to explain how it works.
This is pretty neat. Don’t say your age; you will probably lie anyway!
DON’T CHEAT BY SCROLLING DOWN FIRST
It takes less than a minute. Work this out as you read.
Be sure you don’t read the bottom until you’ve worked it out!
- First of all, pick the number of times a week that you would like to have chocolate (more than once but less than 10)
- Multiply this number by 2 (just to be bold)
- Add 5
- Multiply it by 50 — I’ll wait while you get the calculator
- If you have already had your birthday this year add 1759. If you haven’t, add 1758.
- Now subtract the four digit year that you were born.
You should have a three digit number
The first digit of this was your original number (i.e., how many times you want to have chocolate each week).
The next two numbers are YOUR AGE! (Oh YES, it is!!!!!)
THIS IS THE ONLY YEAR (2009) IT WILL EVER WORK, SO SPREAD IT AROUND WHILE IT LASTS!
So how does it work?
Expressed algebraically, the procedure if you have had your birthday can be written as:
50 (2n +5) + 1759 - y
where n is the number you chose and y the year you were born
The author asserts that this will produce a number where the digit in the 100's place is n and the remaining digits are your age or 100*n + age. If you have had your birthday this year, your age in 2009 can be written in terms of your birth year, y, as
age = 2009 - y
So the formula should produce 100*n + (2009 - y).
It is trivial (I love saying that) to show that
50 (2n +5) + 1759 - y = 100*n + (2009 - y)
This will not work if your age is greater than 99, but as long as you are younger than that, the last two digits will always be your age even if the number of times you want to eat chocolate in a week is greater than 10 -- so in either case eat all the chocolate you want!
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.
Photo used under Creative Commons license. Credit to Kevin Bowman.
Nowadays I'm certain he has no gills, though he can still hold his breath for a long time. He's not quite completely adapted to an aquatic life, though. He suffers from water in the ears. And he hates to hear himself sloshing...
The standard remedy for water stuck in the ears is "SwimEar" - an ad for which reads in part:
"Once water enters this tube...surface tension will cause this water to adhere firmly to the walls of the canal, thereby blocking it. Why is this water so difficult to remove? This is due to surface tension effect as well as the fact that it is extremely difficult to break the vacuum that is created behind the trapped water in the ear canal."
Despite the popping sensation you can get when your ears finally clear from water, there is no vacuum behind the water (really, I'm certain). As the ad implies, the trouble is that water is clingy, and therefore has a high surface tension. The high surface tension is what impedes the flow of water out of the ear canal -- think of getting the water out of a thin straw. The ear canal is behaving like a capillary. Reduce the surface tension and the fluid will release.
SwimEar is just a solution of isopropyl alcohol with a dash of glycerin added for comfort. (Ethanol, or ethyl alcohol, is what we drink - but to a chemist, an alcohol is a molecule that has a "tail" of (mostly) carbons and hydrogens topped off by a hydroxyl group: OH. Ethanol is CH3CH2OH, isopropyl alcohol is (CH3)2CHOH.) The isopropyl alcohol lowers the surface tension of the water (so will a bit of soapy water for that matter).
Horror of horrors - the Romans used lead to sweeten their fruit. No wonder Rome fell! Except that I was willing to read a 1883 paper (in German with healthy helpings of Greek and Latin) to discover that it may be lead and it may be sweet, but the lead doesn't lead it to be sweet.
In a time when mercury was regularly used as a remedy for maladies as serious as syphilis and as commonplaces as constipation, it doesn’t surprise me that lead compounds were in the pharmacopeia. (In all fairness, some modern antibiotics and most chemotherapy agents are at least as toxic as these less old remedies; they just have a better risk-benefit ratio.) Sugar of lead, or as it’s called in the 19th century medical literature, saccharum saturni, is lead acetate: Pb(CH3COOH)2. It was once prescribed for intestinal troubles, an odd choice, since one symptom of acute lead poisoning is an upset stomach. Lead poisoning is also known as painter's colic.
Sugar of lead really is sweet, roughly as sweet per spoonful as sugar. In the 18th and 19th century, lead shot was often dropped into bottles of port, purportedly to make it sweeter - though the more likely effect is anti-bacterial. Why? Lead does dissolve well in alcohol and juices (crystal decanters to store your port are a bad idea) - but I can't find anything that suggests solutions of lead ions are sweet.
The Romans were reputed to use lead acetate as a sweetener. They produced a syrup called sapa by boiling down mildly fermented grape juice in kettles made from lead alloys. (The hydrates of lead acetate are far less soluble in alcohol solutions - you are more likely to get a suspension of crystals in the syrup.) I am suggesting that it’s unlikely that the syrup was sweet because of the lead acetate it certainly contained. An 1883 analysis of sapa produced according to recipes dating from the classical Roman period, in kettles of similar metallic content to those found at Pompeii and other sites, suggested that the lead content of sapa was roughly 850 mg per liter. The equivalent amount of table sugar would be roughly a teaspoon - hardly enough to taste sweet in a liter of liquid. On the other hand, the sugars (glucose and fructose) in the concentrated grape must are the equivalent of 1 cup of table sugar per liter and would certainly swamp any sweetness coming from the lead acetate. It's still not all that sweet. To get a sense of how sweet this is, simple syrup, which has similar culinary uses to sapa, has about 4 cups of sugar in a liter.
I still wouldn't use sapa to poach my pears, but I think it unlikely that the sweet taste of sapa has much to do with lead.
Photo is c. 2009 John4kc. Used with permission.
Beryllium was first identified in 1798 by chemist Louis Vauquelin as an oxide in beryl and emeralds (emeralds are beryls with a bit of chromium added!). Since the chloride salt of the new element tasted sweet, the editors of the journal which published Vauquelin's findings suggested he call the oxide (or earth) glucina from the Greek, glyks (γλυκυς) for sweet. The elemental symbol used was Gl.
Beryllium was suggested as alternative once other sweet metal salts were found, for the gemstones in which the element was first identified. It took until 1949 for this to become the official IUPAC name of the element with four protons.
Beryls were used to make "reading stones," magnifying glasses, then eventually ground into lenses for eyeglasses.
Then I stirred it to dissolve the sugar. And watched the volume decrease to just over 1 1/2 cups of solution! Have I just proved Archimedes wrong? The volume of sugar at first seemed to have displaced the equivalent volume of liquid, but then seemed to vanish...well not exactly into thin air, but vanish nonetheless. As my 15-year old might say, "What's up with that?"
Yes, Archimedes was correct, but his theory did not address substances that dissolve in the liquid. This is a good demonstration of how much "empty "space is in a liquid. The sugar molecules (and other things in brown sugar, which is not terribly pure as chemicals go) insert themselves between water molecules, without needing to push the water molecules further apart. To a good first approximation the volume of a solution made from a solvent and soluble solid is the volume of the solvent used, not the sum of the two volumes.
Try it...it's fun to watch, and it still intrigues me to think about the amount of unused space there is in a liquid that seems so substantial at the macroscopic level!
The pulled pork was a keeper...though the kids found the BBQ sauce too spicy for their taste. Try it on challah rolls!
"I went into the kitchen with another bartender, Stephen Cole, who hunted up a scale and thermometer. He placed the two kinds of ice into separate cups filled with water. We let them sit for 10 minutes. The cheater-ice water proved to be colder (34 degrees compared with 40 degrees), but the ice had lost a full quarter of its weight, compared with just a 14 percent loss in the chunk ice. A cheater-ice cocktail is thus chillier (numbing the taste buds) and more watery (making it flat)."He describes a bar which stocks eight different types of ice - though the classification system is not quite what a physical chemist might use - or even Kurt Vonnegut. I suspect, however, a serious flaw in the experiment, and therefore in the conclusions drawn about the effect of ice type on a drink.
Take a mixture of ice and water that has been thermally isolated (put in a thermos!) and allow it to come to thermal equilibrium (let it sit until the temperature doesn't change any longer). When the contents of the thermos reach equilibrium, if there are both ice and water present, the temperature is 32 degrees (Fahrenheit). It does not matter how cold the ice was to start, how much water is present, how warm or cold the water was - it will be 32 degrees. Not 40. Not 34.
Also known to those who know how to read a phase diagram, ice at normal pressures will not start to melt until it reaches 32 degrees, and its temperature will not rise above 32 degrees until it has all melted. Curtis' experiment isn't quite as sophisticated as the thermos one I've sketched out, but assuming that the rate of heat loss to the room was small (air - or any gas - isn't a very good thermal conductor, so over the short term this is not a bad assumption), and that the ice and water used were pure, and that a very large amount of water was used relative to the ice - I find it untenable that the "cheater-ice" cocktail is different in temperature than the one made with less porous ice. More watery, yes, colder, no.
Photography by Sue Stafford. Used under Creative Commons license.
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!)
The second issue of Nature Chemistry appeared online today, with my musings about the shapes the periodic table can take, and why I think chemists like to keep their elements in boxes.
"Chemists have created hundreds of variations in search of the perfect periodic table. The periodic table has been mapped onto spirals, circles, triangles and elephants. The first such “alternative” periodic table, based on a sprial, was proposed by Gustavus Hinrichs of the University of Iowa in 1867, two years before Mendeleev published the forerunner to the current blocked tabular form. Still, open 50 random introductory chemistry texts and it is a fair bet that all 50 of them have IUPAC’s standard periodic table inside, or its generic sister. Chemists are stuck in the box." Read the rest of the column here (requires a subscription...).Or if my Table Manners are not to your taste, this article in the same issue on syntheses of Moebius molecules might be.
While medieval alchemists were searching for the secrets of turning base metals, such as lead and tin, into gold, medieval artists had already figured out how to do this. Gold was often applied to manuscripts in medieval Europe and the Middle East to “illuminate” them, an illuminated page would have the functional equivalent of little mirrors scattered across it, making the most of dim interior lighting. In addition to being reflective, gold does not corrode or oxidize, so gold will not discolor with time. There is a fine collection of medieval illuminated manuscripts at a library near me, and as you turn the pages of Book of Hours that is half a millenia old (wearing gloves, of course), the golden decorations wink at you as brightly as the day they were applied.
Gold is expensive, and hard to handle, particularly in the thin sheets necessitated by the cost. One alternative is to use a tin base, then brush on a saffron oil glaze. Polish it up and you might not notice. The glaze blocks out the oxygen and moisture in the air, preventing many of the chemical reactions which can cause the metal to discolor. The resulting preparation is called auripetrum - Peter’s gold. Peter had a good idea - whoever he was.
Does anyone know more about the source of this name? I'd love to know.
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).
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.
By 1897 Franz Pfaff of Harvard had weighed in. Toxicodendric acid extracted from poison ivy turned out to be acetic acid - yes, vinegar, by another name, CH3COOH. He showed the itch was in the oil.
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!