Standards fascinate me. One of the most problematic standard in use almost universally today is the kilogram (kg). The problem is that no one really knows exactly how much mass a kilogram actually has. By extension that means that no one knows how heavy a pound is either since the US government defines it in relationship to the SI kg unit.
Originally the metric system was supposed to be defined in terms of “natural laws” that the common man could measure for himself. The kg was originally defined as a cubic decimeter of water under certain conditions. This is probably what you were taught in school, one of many metric misconceptions (see why everything you know about the metric system is wrong).
But that approach was jettisoned as impractical due to variations in water density, temperature, etc. In 1889 the standard became defined by a set of “physical prototypes” that were manufactured and distributed to major countries. So what was a standard based on “natural laws” became based on an arbitrary hunk of platinum and iridium.
Only that has not worked either (at least not to the number of significant digits desired). The problem is that the different physical prototypes are changing mass by a small but measurable amount. So today there is effectively no precise consistent definition of a kilogram, and thus by extension the pound.
The plan going forwards is to define the kg in terms of basic physical properties, similar to what has been done with the meter and the second. But for now, kg is only an estimate for given levels of precision.
I get a steady stream of indignant sputtering about this post on the metric system and what it means for authentication. One common point that readers make is that Celsius is better than Fahrenheit because it is based on natural law, defined as 100 degrees between the freezing and boiling point of water.
Only it isn’t, and hasn’t been for some time (at least not since 1954). While the freezing point and boiling point of water was precise enough in the 1700’s, it is no where near precise enough to act as a standard. The reason is that no two samples of water will melt and freeze at the same temperature due to variations in water purity, air pressure, and humidity.
By international convention, the Celsius scale is defined by a range between absolute zero and the thermodynamic triple point of Vienna Standard Mean Ocean Water (VSMOW). This point, by the way, is 0.01 C. And VSMOW is not ocean water (despite it’s name), but rather is a carefully crafted lab concoction comprised of specially defined proportions of oxygen and hydrogen isotopes.
So while we are taught Celsius is defined by the freezing and boiling points of water, it is actually defined by absolute zero (which doesn’t exist in the natural world), and the triple point of a form of water that only exists in the lab.
Explain to me again, why this is less arbitrary that Fahrenheit?
And why is it still taught incorrectly in schools (at least in the US)?
In 2006 a lack of adult supervision allowed the EU parliament to pass an ill conceived initiative called REACH. The REACH program will require retesting for toxicity every chemical in use in the EU that predates the newer testing regimes.
Now there is a report that estimates it will cost industry 9.5 billion Euros and require 54 million test animals. All to test chemicals that are already in wide-spread use.
Scientific illiteracy is quite expensive.
In the Pipeline is my favorite chemistry blog. He has a regular series called “Things I won’t work with” in which he describes chemicals so dangerous the even he (as a professional chemist) won’t allow in his lab. In his most recent installment he describes a chemical so foul smelling that it made is forbidden list on that basis alone. Here he names Hell’s Dumpster:
My recent entries in this category have, for the most part, been hazardous in a direct (not to say crude, or even vulgar) manner. These are compounds that explode with bizarre violence even in laughably small amounts, leaving ruined equipment and shattered nerves in their wake. No, I will not work with such.
But today’s compound makes no noise and leaves no wreckage. It merely stinks. But it does so relentlessly and unbearably. It makes innocent downwind pedestrians stagger, clutch their stomachs, and flee in terror. It reeks to a degree that makes people suspect evil supernatural forces. It is thioacetone.
Or something close to it, anyway. All we know for sure is that thioacetone doesn’t like to exist as a free compound – it’s usually tied up in a cyclic thioketal trimer, when it’s around at all. Attempts to crack this to thioacetone monomer itself have been made – ah, but that’s when people start diving out of windows and vomiting into wastebaskets, so the quality of the data starts to deteriorate. No one’s quite sure what the actual odorant is (perhaps the gem-dimercaptan?) And no one seems to have much desire to find out, either.
Interesting research for some brave and ollifactory challenged soul.
If you haven’t read the rest of the things in the list, you should. It’s especially frightening to know there is a chemical that sets sand on fire and eats through asbestos fire brick.
Posted in Science
Tagged Chemistry, Fun
I briefly considered chemical engineering as a freshman, but it didn’t take. Had I known then what exciting lives some chemists lead I might have given it more thought. I just discovered this delightful blog category titled “Things I Wont Work With“. What kind of chemicals might scare the bejeezers out of a professional chemist? How about this:
Did I mention that this prep was performed on less than one millimole? Spirited stuff, that tetra-azide. The experimental section of the paper enjoins the reader to wear a face shield, leather suit, and ear plugs, to work behind all sorts of blast shields, and to use Teflon and stainless steel apparatus so as to minimize shrapnel. Hmm. Ranking my equipment in terms of its shrapneliferousness is not something that’s ever occurred to me, I have to say. It’s safe to assume that any procedure which involves considering which parts of the apparatus I’d prefer to have flying past me will not get much business in my lab, no matter how dashing I might look in a leather suit.
That procedure deserves a closer look, though. You can’t just crack open a can of selenium tetrafluoride whenever you feel the urge, you know. That stuff has to be made fresh, as far as I can see, and the way these hearty sons of toil make it is by reacting selenium dioxide with chlorine trifluoride. Yep, that stuff, the delightful compound that sets sand on fire and eats through asbestos firebrick.
So if you’re going to make selenium polyazides, your day starts with chlorine trifluoride and I’m sure that it just rolls along from there. Before you know it, you’ve gone from viciously reactive halogens, paused to prepare some disgusting selenium fluorides, made some violently unstable azides that explode if you stick your tongue out at them and hey, it’s dinnertime already. . .
Fun with chemistry!
There is this disturbing story from Make magazine (hat tip to Instapundit):
The Worcester Telegram & Gazette reports that Victor Deeb, a retired chemist who lives in Marlboro, has finally been allowed to return to his Fremont Street home, after Massachusetts authorities spent three days ransacking his basement lab and making off with its contents.
Deeb is not accused of making methamphetamine or other illegal drugs. He’s not accused of aiding terrorists, synthesizing explosives, nor even of making illegal fireworks. Deeb fell afoul of the Massachusetts authorities for … doing experiments.
Authorities concede that the chemicals found in Deeb’s basement lab were no more hazardous than typical household cleaning products. Despite that, authorities confiscated “all potentially hazardous chemicals” (which is to say the chemicals in Deeb’s lab) from his home, and called in a hazardous waste cleanup company to test the chemicals and clean up the lab.
Pamela Wilderman, the code enforcement officer for Marlboro, stated, “I think Mr. Deeb has crossed a line somewhere. This is not what we would consider to be a customary home occupation.”
Allow me to translate Ms. Wilderman’s words into plain English: “Mr. Deeb hasn’t actually violated any law or regulation that I can find, but I don’t like what he’s doing because I’m ignorant and irrationally afraid of chemicals, so I’ll abuse my power to steal his property and shut him down.”
The sadly inevitable result of combining scientific ignorance with petty bureaucracy.
They will get my chemistry set when they pry it from my cold dead fingers.