Cocktail Party Physics

nanoparticles and microparticles making things slippery

My last post focused on G-Oil, a new motor oil that uses beef tallow as a base, thus decreasing America's dependence on foreign energy sources.  One thing I didn't address in that blog is the role of nanotechnology in oils -- which is because I had to learn some things first.  

The G-Oil website has a section on nanoparticles, mostly focusing on the fact that the surface area to volume ratio of a nanoparticle is quite large.  This is true, but it doesn't tell you why that has anything to do with making oil perform better. 

The words "NANO GEODESIC BEARINGS" attracted my interest not just because they were in all caps, but because anytime you hear 'nano' and 'geodesic' together, you have to think buckyballs, those carbon structures resembling soccer balls that spent way too much time in the dryer and shrunk to about a nanometer in diameter.

Incidentally in my search for buckyballs, I stumbled across a toy called buckyballs that is unfortunately named.  It's a collection of 216 magnetic ball bearings that technaBob describes as "fun, powerful choking hazards".  You can make 3D structures like cubes, pyramids, etc.  But as a magnetician, I'm a little miffed that the magic of magnetism has been ascribed to carbon.  Carbon has its strengths, but magnetism really isn't one of them.

Buckyballs can form a solid very similarly to the way atoms form a solid.  The crystal structure is face-centered-cubic (fcc), so imagine a repeating structure of a cube with a buckyball at each corner, plus one in the very middle of each face of the cube, like the photograph at left (which is made of they toy "buckyballs"). 

Buckyballs aren't the only molecules that can do this. There is a whole class of crystals called molecular crystals that use molecules instead of atoms as their building block.  Most atomic crystals have an atom at each lattice site and the atoms are connected by very strong bonds (usually ionic or metallic).  The bonds holding molecular crystals together are much weaker, so the molecules have a little more freedom of motion than the atoms.  In some molecular crystals, the molecules can change orientation while maintaining their location in the crystal.  When buckyballs form a solid, they can spin in place.  Imagine the individual balls in the picture rotating while always maintaining the shape of the cube. 

That suggests the idea of buckyballs as tiny ball bearings isn't such a far-fetched idea, especially since the buckyball's second cousin once removed, graphite, is an outstanding lubricant.  That idea doesn't really hold water.  Graphite lubricates because it is made of sheets of carbon atoms that separate when you apply force.  The separation releases minute quantities of gas that act like atomic ball bearings. 

Sure enough, most of the people who tried using buckyballs on surfaces like aluminum and stainless steel found that high concentrations of buckyballs resulted in a compacted mess with extremely high friction and low concentrations of buckyballs produced no difference in behavior compared with the bare surfaces.  The problem, it would seem, is that you need to have the buckyballs held in one location with the freedom to rotate.  And if you think about it, that's pretty much how ball bearings work anyway.

In 1996, Jacob N. Israelachvili and co-workers at UC-San Diego showed that adding buckyballs to organic solvents allowed the liquid to flow more freely against mica surfaces.  The UCSD researchers explained the increased lubricity by suggesting that very small numbers of buckyballs layers deposit themselves along the mica surfaces.  The bonds between the buckyballs and the surface are not very strong, which leaves them free to rotate as they do in the solid phase.  The buckyball rotation allows the liquid molecules to move past the mica surfaces much more smoothly than they could otherwise.

I thought perhaps this was the mechanism that explained the buckyballs in G-Oil, but the UCSD work was organic solvents against mica at room temperature.  That doesn't necessarily translate to motor oil against metal surfaces at high temperature, the conditions found in an engine. 

I found a fair number of number of technical articles claiming that buckyballs do not markedly enhance the lubricity of motor oil. They do, however, improve the thermal conductivity of the oil and that makes the oil better at carrying heat away from the engine.  Overheating is one of the more severe problems in racing because it's hard to go fast when your pistons are starting to melt.

More searching led me to a patent application that combines nanoparticles and microparticles in oil to improve fuel efficiency.  The nanoparticles are made from hard materials, like alumina, diamond, ceria and titania -- the type of materials you'd use to polish things.  The microparticles (which are 100-1000 times bigger than the nanoparticles) are softer materials like zinc oxide, graphite, talc, and copper oxide. 

One of the problems with friction in your engine is that you lose energy because pieces have to move through the viscous oil.  Another problem is that two surfaces that rub against each other at high heat are constantly exchanging atoms, so your parts go from a flat surface to a surface that has microscopic dips and bumps.  Even though you can't see the imperfections with your bare eyes, those little divots and bumps impede the motion of the parts against each other.

In the patent application, the nanoparticles are made from hard materials because part of their job is to polish the insides of your engine and keep them nicely smooth.  The soft microparticles are designed to embed themselves into materials that have developed microsized defects.  The combination of the two types of particles, the patent submitter claims, can decrease the coefficient of friction from 0.22 to 0.01.  (The coefficient of friction ranges from 0 to 1 for abrasive friction:  a passenger car tire on asphalt is about 0.7-0.8.)

Another role I know about for nanoparticles in oil came from a discussion with Professor Shah at the University of Delaware a couple of years ago.  He told me about putting alumina or titania nanoparticles in oil to increase the heat capacity of the oil.  This initially confused me because both alumina and titania are thermal insulators.  Copper is an excellent thermal conductor, so I would have guessed a metal of some type would be a good bet to improve heat conduction.

And I would have been wrong.  Temperature is the motion of molecules.  Solids are much better at conducting heat than liquids or gases.  In the alumina nanoparticles in oil, Professor Shah told me that the oil forms a semi-crystalline layer coating the nanoparticles, and that semi-crystalline layer is better at dispersing heat than the liquid oil. 

So I'm guessing that the primary role of buckyballs, or any carbon additives is primarily in polishing the surfaces of mating parts. Oil has to deal with very high pressure, as its whole purpose is creating a very thin film between two pieces so that they slip smoothly past each other. The current additives used for pressure are sulfur and/or phosphorous additives, which can actually encourage the parts to corrode, so using buckyballs for oil used in gearboxes, for example, would make sense.

It's sort of funny that so many manufacturers use 'nanotechnology' in their advertisements, as if just the fact that they put something in their product that is really small should be enough to sell you on their product.  I'd really rather know exactly what's in the product and why -- especially if it's something I'm going to put on my face.

how many horses under the hood..? none - i've got cows.

In February, I had the privilege of attending the 12 Hours of Sebring, an American Le Mans Series (ALMS) race.  The ALMS series isn't as familiar to people in the US as NASCAR, the series that originally got me interested in cars. Drivers in both series have accents; however, in NASCAR, you're distinguishing the Virginians from the North Carolinians, while in ALMS, you have to be careful about confusing the Spanish, Mexicans and the Brazilians or the Australians and the Brits.  (And then there are the 'citizens of the world', but that's a story I will tell later).

In comparing the two types of racing (stock cars vs. sports cars), NASCAR is like hockey and ALMS is more like baseball.  At a NASCAR race, you constantly scan the track to see where the action is.  Except at superspeedways and road courses, you really can't hold a conversation because of the noise.  You have to wait for cautions to communicate with your seat mates (or text them).

ALMS tracks are longer:  three to five miles compared to the typical half-mile to two-and-a-half mile NASCAR track.  When you go to an ALMS race, you position yourself near your favorite turn.  The cars run past, then you have a minute or so to talk before they come back around again.  Drinking while watching racing is common (if not mandatory); however, NASCAR's official alcoholic beverage is Coors Lite, while ALMS's is Patron Tequila.  I'm a sucker for good tequila and a British accent, so I had a lotof fun at Sebring.  Besides, where else are you going to see an Aston Martin sponsored by Lowes?  

ALMS is a good platform for automotive industry companies pursuing greener products.  The Michelin Green X Challenge, which rewards the fastest and most energy efficient cars, considers only gasoline usage at the moment, but as the series evolves, they will likely expand to include another major contributor to petroleum use in cars:  oil.  One of the series' sponsors, G-Oil, is a motor oil with animal origins.  One of the principles of "green racing" is to minimize petroleum usage to lessen our dependence on foreign energy sources, so using a domestically available source for motor oil certainly addresses that point. 

Oil plays many roles in the engine, including protecting metal parts from wear due to friction and carrying heat away from the engine.  A typical passenger car uses about 5 quarts of oil.  Changing the oil every 5,000 miles means you go through about 100 quarts of oil in 10 years.  That doesn't sound like much, but multiply that by the number of cars in the country and the number of people who don't recycle used oil.  The Environmental Protection Agency (EPA) says that two hundred million gallons of used oil are improperly disposed of each year.  So not only are we increasing our dependence on petroleum, the used oil can contaminate groundwater and kill vegetation.

Gasoline and petroleum-based oil come from the same source: crude oil.  Crude oil contains a veritable zoo of hydrocarbons - chains (or rings) of carbon atoms with hydrogen atoms attached to any free carbon bonds.  The number of carbon atoms in each molecule ranges from 1 to 80 or more. The chart below gives you an idea of how many carbons are in the molecules that make up various petroleum products.  Red lines represent gases, blue lines represent liquids and green lines represent solids.  The darker blue tells you where the majority of the molecules in the substance come from.

The same length carbon chain molecules can be used for different things, depending on how the atoms are attached within the molecule.  Isomers are molecules with the same atoms, but different arrangements of those atoms.  For example, there are 355 isomers of C₁₂H₂₆ (a molecule containing 12 carbon atoms and 26 hydrogen atoms).  So even though a narrow range of carbon number is present in gasoline, There may be as more than 500 different molecules involved.

A barrel of oil is 42 gallons, with a typical barrel providing about 19.5 gallons of gasoline, 9 gallons of fuel oil, and 4 gallons of jet fuel.  The remainder is used in a wide variety of products, including grease, kerosene, bitumen (the binder in asphalt), crayons and plastics.  Motor oils are about 90% base oil (the 'motor oil') you see in the chart above, and the other 10% are additives to decrease friction, increase viscosity, prevent corrosion and oxidation, etc. 

Saturated and unsaturated fats are just as important for cars as they are for our bodies.  (The general agreement as far as nomenclature is that fats are solid and oils are liquids.)  Each carbon atom can make four bonds.  Hydrogen can make just one.  Saturated fats - like animal fats - have single bonds between carbon atoms, and single bonds between each carbon and hydrogen atom, as shown in the top part of the figure below.

Unsaturated fats (or oils ) have a double bond between the carbon atoms and each double bond decreases by one the number of hydrogen atoms in the molecule.  Unsaturated fats have fewer hydrogen atoms than saturated fats.  If there's one double bond, the fat is unsaturated, and if there is more than one double bond, the fat is poly-unsaturated.(Thanks to Juan for pointing out that the original in this figure violated the most fundamental laws of chemistry!)

Double bonds are more exposed than single bonds, making them more likely to react. A particular challenge is oxidation, which cleaves the carbon chain at double bonds.  The extra reactivity of unsaturated fats means that the human body can break them down faster and easier.  Unsaturated and polyunsaturated fats are used more quickly in the body’s metabolism, while saturated fats hang around and clog up your arteries.

In your car's engine, hanging around is what you want.  Motor oils use saturated fats because they are more stable.  You've probably never had motor oil go rancid on you, have you?  Saturated fats stay in their fatty form far better than unsaturated fats.  Saturated oils are good for your car, even if they are not so good for you.  One of the problems with double bonds, though, is that they are much more likely to oxidize, which cleaves the double bond and produces two shorter molecules, neither of which has as much protective ability as the original long-chain molecule.  The propensity for oxidation increases with temperature, and engines get very hot. 

The desirable properties of the oil come from the particular molecules that are present.  Motor oils are usually somewhere around 16-20 carbons per molecule.  It doesn't really matter where the oil comes from:  it can be separated out of crude oil or, in the case of G-Oil, it can come from animal fat. 

G-Oil is made from beef tallow - tallow was historically used for candles, as it was cheaper than wax. Oil obtained from refining crude oil is obtained by separating out different components from the crude oil.  Animal or plant fats offer some advantages in terms of processing because they contain high levels of triglycerides. 

Triglyceride is a very large molecule composed of one glycerol molecule and three fatty acids. The fatty acids are represented R1, R2 and R3 in the picture to the left.  The triglycerides go through a process called transesterification, which frees the fatty acids from the glycerol.  Remember learning about how the pilgrims made soap from animal fats and ash?  This is exactly what they were doing.  The glycerol is used in soap and the fatty acids that were left were used to make candles or other products.  This is also the first step you would use to make biodiesel from fat.

It turns out that the fatty acids in beef tallow have very high proportions of carbon chains in the C16-C18 range, which is the target range for motor oil.  Green Earth Technologies, the company making G-Oil, has a patent pending process that converts the fatty acids into the types of chains needed for motor oil applications.  

You might wonder why they don't use plant fats, and that's just because the animal fats are closer to the right composition of molecules.  Plant oils have a much larger fraction of unsaturated hydrocarbons.  The G-Oil website points out that grape seed oil is rich (70-80%) in Omega-6, an 18-carbon chain with two double bonds.  These molecules degrade much faster than those in the animal fats.  The end message is that the plant fats are better for use by people and the animal fats are better for use by cars. Green Earth Technologies points out that the amount of beef tallow they use is a small percentage of what is already being produced as a by-product of meat processing.  

The oil -- and all of it's additives that protect it from oxidation, ash production, etc. -- are biodegradable, meaning that it breaks down within about a month when in contact with common environmental bacteria.  Which means that, no, the oil will not biodegrade in your engine.  I guess if you are a committed vegetarian, you might choose not to use this produce because it is animal-based, but other than that, this is pretty nifty idea.

Perhaps most importantly, you don't have to sacrifice performance for being green.  The oil was tested against a couple leading synthetic and crude-oil-based motor oils and G-Oil compares very favorably. The ALMS series believes that motorsports is a good platform in which to test things that eventually could appear in passenger cars, as is noted on the hauler set up of Drayson Racing (shown below).  Lord Drayson, the co-owner of the team with his wife, is the UK's Minister of Science and Innovation, a very cool guy who actually tries to explain what is going on in Science and Engineering to the public via twitter.  I wonder what U.S. Secretary of Energy Paul Steven Chu drives...? 

I haven't explained the role of nanotechnology in lubrication:  that will be coming in my next post because it turns out the solution is bigger than I originally thought!

 

 

what an ash

I was waiting for people to unload on a flight in Dallas that had been delayed because of strong thunderstorms there.  DFW is a major hub for American and many people were pushing to the front, anxious about making connections.  The man in the row in front of me got irritated at a woman and her husband who had actually started walking up the aisle while the plane was still taxing to the gate. 

"I guess you're more important than the rest of us", he said.

"It's the airlines fault," she retorted. "They're making us late. They can't do anything right."

Yeah, cuz American planned the thunderstorms that delayed the plane coming in to DC, which delayed our take off.  And what were they thinking when they delayed us even further by taking a longer route to avoid flying through the thunderboomers?

My favorite line, though, took place in the DC airport when the delay was announced and someone actually said.  "I don't see how weather can be delaying our flight - just look outside:  it's perfect."

Expect more opportunities for people to display their lack of being embarrassed at their own ignorance today, especially for those unfortunate enough to be flying to Scandinavia or the U.K.  (You can get a real time view of the air traffic here.  France is really hopping today.)  A quick look at the Heathrow arrivals board reflects the fact that everything flying into London today is canceled.  I can just hear people now:  "But the volcano was in Iceland.  Why should that delay my travel within England?"

The volcano that erupted yesterday, called Eyjafjallajokull (I am afraid of injuring my tongue if I even try to pronounce that) in Southern Iceland is actually within a glacier. Its last eruption in 1812 prompted a "me-too" from nearby (and much more reasonably named) glacial volcano Katla.  Katla is much larger and hasn't erupted since 1918.  As if a volcano eruption weren't enough, because the volcano is within a glacier, an eruption also melts ice, and the primary reason for evacuation was because of fears of flooding.  The eruption site has been named Fimmvörðuháls.

A volcano typically spews a lot material into the air when it erupts.  Thanks to gravity, the largest pieces of rapidly solidified magma (a.k.a. "volcanic bombs") come down pretty quickly; however, the smallest pieces of ash can remain airborne for days to weeks. 

When Mount St. Helens erupted in Washington in 1980, it took just 30 minutes for the ash plume to reach 90,000 ft and just 15 hours to travel 600 miles downwind.  The ash plume from the Iceland volcano is mostly in the 6-11 kilometer range, which is about 20,000-36,000 feet.  Nowhere near as high as Mt. St. Helens, but the ash  cloud is well into the heights at which aircraft normally fly.  The speed at which the cloud is moving and its trajectory will determine how long air travel is stalled.  There are nine volcanic ash centers throughout the world tasked with tracking volcanic ash.  The London office is posting regularly updated graphics of the path of the ash cloud.)

Ash is composed of particles on the order of 2 millimeters or less in diameter that are made of pulverized rock and/or glass (as shown at right).  The pieces smaller than volcanic bombs (which are 64 cms and up) and larger than ash are called lapilli. Ash particles are entrained in the gas from the volcanic vent and sent high into the air, where they are carried away by prevailing winds.  In this case, the winds are directing these tiny particles toward northern Europe and the U.K. and that is the reason for all the canceled flights.

What does an airplane have to fear from 2 mm particles?  It's not like a duck or a goose flying into an engine, after all. 

Well, we can start by noting that very small particles of glass and rock hitting something at high speed is basically sandblasting.  Not very good for visibility and it can cause real damage to windows and paint jobs.

Next, we have to worry about airplane engines (cutaway courtesy of wikipedia.)  The intake of an airplane engine (far left) brings air into the combustion chamber.  The particles are small enough that they have no problem getting in past the intake and combustion stages (unlike birds).  When the particles reach the combustion stage, however, they get hot enough to soften or melt and instead of going through the engine, they stick on the turbine blades.  Once enough of the particles have accumulated, they block the flow of air through the engine, the engine stops generating thrust and the aircraft plunges.  This has been documented in about 20 civil aviation craft, in which the plane was essentially a glider for 5-10 minutes.  During that time of freefall, the engine usually cools, the particles agglomerates get pushed out and the engines can be restarted.  But that's an awfully uncertain way to unclog an engine.

Compounding the problem is that standard radar can't detect the difference between water vapor clouds and volcanic ash clouds.  Radar sends out radio waves - more recent radars use waves that have a wavelength on the order of a few centimeters.  The radio waves run into things and bounce back to the source.  The time it takes to return tells you how far off the object is.  (In the more complicated case of Doppler radar, the shift in frequency is used to determine how fast the object is moving and in what direction, increasing the precision of the technique.)

Radar works because of the interaction of the outgoing waves with the object trying to be detected.  Radio waves are electromagnetic in nature, so what changes their path is a change in the dielectric constant or diamagnetic constant. The dielectric constant measures how well a material concentrates electric flux lines. We chose vacuum to have a dielectric constant of 1, meaning that the electromagnetic waves travel through vacuum without change.  Air has a dielectric constant pretty close to 1 - so close that we normally don't bother treating it as different from 1. 

Materials with larger dielectric constants are polar - they have a decidedly positive end and a decidedly negative ends. When left alone, the directions of the position and negative ends are random.  When an electric field is applied (right picture), the dipoles (the little things with positive and negative ends) align along the electric field lines.  Diamagnetic constant is basically the same thing, but thing of the plusses and minuses as north and south poles instead.

The larger the change in dielectric constant, the more the electromagnetic waves scatter.  We generally measure the dielectric constant as a relative number (relative to vacuum).  Metals have huge dielectric constants because they have a lot of free electrons running around (and remember that the lack of a negative charge is a positive charge, so if all the electrons move to one side of the material, that leaves a positive charge on the other).  Aluminum has a relative dielectric constant on the order of 10¹⁴, which is 100,000,000,000,000.  (For the purists, that is at frequencies of about 1 kHz).  Water has a relative dielectric constant around 80.  Basically, the more conductive something is, the easier it is to see on radar.  Also, the sharper the interface between air and the object, the easier it is to spot.  That's why a stealth plane is all rounded curves - harder to detect.

Another way of preventing radar detection is to use non-electrically conductive materials.  Teflon has a relative dielectric constant of around 2, for example.  Volcanic ash is basically rock and glass, both of which have pretty low dielectric constants, plus, at a size of a few mm (compared to a few cm for the radar waves), they are difficult to detect unless they are in very large masses. Even then, they are indistinguishable from regular clouds.

There are some attempts to differentiate between volcanic ash clouds and water vapor clouds, mostly using other frequencies of electromagnetic radiation.  There is a resonance in reflection near 11 and 12 micrometers from water.  The volcanic ash particles and the clouds react very differently to the radiation, so a combination of radar and infrared radiation could allow pilots to identify volcanic ash in real time.

How long is this going to go on?  The original volcano started erupting on March 20th.  The 1812 eruption lasted for slightly more than a year.  Yesterday's ash cloud is the result of a particularly large burp.  About the only thing more unpredictable than the airlines is volcanoes.  Between more possible eruptions and uncertainties about the wind direction and speed, it is hard to predict how long the travel ban will last.

Looking on the positive side, Rayleigh scattering should be enhanced by the volcanic ash.  This should result in a spectacular sunset.  Plenty of people will have time to watch it:  It doesn't look like they are going anywhere until tomorrow at the earliest.

China report

  I've been back from China for about a month and I'm still processing the experience, but I thought I'd tell you all a little about some of my observations in and out of the classroom. I was hired to teach English language and culture but really, in three weeks, there's not much language teaching you can do, so it mostly winds up being an English culture summer camp and conversation program. Which is great. There's a lot more learning of language that goes on in informal sessions than formal ones, and it was really a pleasure to get to know both the students and faculty of the Harbin Institute of Technology (HIT).

Harbin is an industrial city in the north of China, with a population around the same size as New York's. As Chinese cities goes, it's pretty new, springing up in the late 1800's when the Russians built a railroad from Vladivostok to a sleepy fishing village on the Songhua River for trade purposes. Russian Jews migrated there and helped build the city, giving Harbin its first hospitals, schools and libraries as well as two synagogues and a sizable cemetery that's still lovingly cared for by the Chinese. At one time the city housed an international, multiethnic population and was called the Paris of China, and passed through both Russian and Japanese hands before becoming wholly Chinese. Now, its population is almost exclusively Chinese, with a few Japanese and Korean residents. (If you're interested in pictures, you can see what I took at my Flickr account, or our fearless leader, Marcy Bauman's. You can also take a look at my blog posts about the trip.)

The city has a number of universities and top-notch schools. HIT is the third-best university in China, on par with our MIT and like MIT, focused on science and technology fields. The students are chosen from the top 2.5 percent of those taking the national admissions exam, so they are smart, smart kids, and HIT tends to promote from within its graduate population. One thing the language barrier often does is disguise just how darn smart folks are, and I know I was underestimating the intelligence of most of the people I was talking to. The few technical conversations we had were as much hampered by my lack of technical vocabulary as their lack of English vocabulary. I met aerospace, civil, environmental and all other kinds of engineers, materials scientists, chemists, computer scientists and new media specialists, economists and architects, and people specializing in technological innovation, with research areas as diverse as composite materials, solid oxide fuel cells, optical thin films, and microporous and mesoporous materials. Many of my students were studying alternative energy technologies and environmental sciences.

These last two subjects are big issues for China, and you can see the need for them all over Harbin itself. The weather was beautiful during the first week of my stay: warm and dry and windy. I was really puzzled when people kept asking me if I found Harbin's air dirty. And then the next week we had a temperature inversion and I understood the question. You can see the difference in the two photos I took from my 15th floor window on campus:

There's blue sky underneath that smog, believe it or not. And that's the way it was for most of my visit. It's not eye-stinging or smelly like the air in Pittsburgh was when I lived there in the late 70's, but it makes New York on a bad day seem edenic. Ozone shmozone. Most of what's in the air is not car exhaust but coal smoke. There were several coal-fired electricity plants on campus, and that's where most of China's power comes from. At least in Harbin, cars are a relatively small part of the problem because there just aren't that many per capita yet (not so for Beijing and Shanghai). That doesn't stop the traffic from being completely insane, but that has more to do with the total disregard for signs (if there are any) and rules of the road than numbers. And the donkey carts don't help, either, I'm sure. Especially the ones on the expressway. Or the massively laden trikes.

If Harbin is any indication, one of China's biggest priority has got to be infrastructure. I'm used to not being able to drink the water when I go somewhere out of the country, but in Harbin no one drinks the water. You can wash in it, and wash your clothes and dishes, but you can't drink it because there are no purification plants and largely unregulated wastewater dumping. Cooking and drinking water is all bottled, which adds its own problems in recycling (that's what the guy on the trike is hauling, incidentally). In one of the first conversations I had with the faculty when school started, I spoke with a prof whose specialty is construction materials and engineering and we talked about the lack of regulation in China, not only in building materials and codes but in industry as well. Where we have legislation like the Clean Air and Clean Water Acts (however badly they're enforced), China has nothing but local committee oversight, which is subject to bribery and corruption. (Interestingly, while I was writing this, the New York Times published the first of a series called "Toxic Waters: America's Growing Pollution Problems." So it's not like we're doing such a great job either. But the major difference is that we have the legislative framework to deal with it.) There seems to be a major push in Harbin, to correct some of these issues, at least on the wastewater front; streets all over the city were torn up both for new sewage and water lines and for a new subway the city is putting in. And many of my students were keenly interested in environmental issues and abatement technology. I got a lot of questions from both faculty and students about how pollution is managed in the States (and was grateful for 10 years of editing environmental impact statements to give me the background to answer them).

But the two issues that really struck me as an educator and a science geek were the attitude toward education in general and how different it is talking about science without religion getting in the way. I was teaching mostly incoming freshmen and sophomores, and not only were they some of the brightest students I'll ever have the privilege of teaching, I've never had students who were so eager or so respectful. This program was basically a three-week summer camp and still there was nothing my students balked at doing. Homework? Sure, no problem! Write in class? No problem. Ask me awkward questions about Tibet? Sure, happy to. Eat lunch with you? Absolutely. Students were on time, every day, or almost humiliatingly apologetic if they were late. They stood up to answer me in class. And thanked me after each one. After day one, I was reeling with culture shock. This is not to say my students here are not hungry or grateful, but in a completely different way. My students here know they've missed out on something and want to make up for that so they can get good jobs and support their families. The intellectual hunger in Chinese students is just that: intellectual hunger for new ideas, new ways of thinking, new information.They have a visceral love of learning you see in some of the best schools here and with individual students even at third tier U.S. schools. In part, that's because getting into college is so competitive, even more so than here. The major difference, and something I missed, was that Chinese students won't often argue with you. They're so respectful, and often used to learning by rote, that disagreeing with a professor seems rude to them. Teachers are really important people in China, and paid accordingly. We could really learn something from that.

And yet, one of the faculty and I had a conversation about this and he insisted that U.S. schools were still superior because we taught students to think independently. Gosh I wish that were still true. As I recently said in another conversation over here, our schools are leaning more and more toward shaping students for particular careers and offering them skill sets, rather than the ability to learn quickly and think for themselves, which can be applied in any career. (I'm not saying you don't need skill sets, especially in the sciences, but along with that, you need critical thinking skills and imagination, rather than just the skill sets. It's what sets a technician apart from a scientist.)

The unit that I taught was about science in the U.S. and covered a little history of science (the development of the scientific method, major discoveries, major players); the two-way exchange between science and culture; women in science; science in entertainment (thanks, Jen!); communicating science; current controversies; and how the public views science. We watched a couple of CSI episodes, Minority Report and The Matrix, and a couple of clips from Babylon 5. Some of the entertainment was familiar, and some not, but the references that went right over everyone's head were the religious and mythological allusions in The Matrix—not surprising, since that same stuff goes right over my head in Chinese opera. More confusing for them, though, was the whole idea that people would actually disbelieve scientific fact in favor of religious teachings or myth. When I described the controversies about teaching evolution in public schools and what ID and creationism were, they were clearly boggled. When I asked how many of them had some sort of spiritual belief, whether Buddhism, Confucianism, Islamic, or Christian, not one hand went up. (Just to clarify, each of those religions is legal in China; there is an active Buddhist temple in the city, some of the faculty are Buddhist, and though the Jewish population is long-gone, their synagogues were not razed during the Cultural Revolution as were most of the Christian churches. So this wasn't fear of reprisal that kept them from professing religious belief. It was simple lack of interest.) For the Chinese, if anything plays this role in forming or deforming scientific thought, it's politics, and I think that's less true now than it was during, say, the Cultural Revolution.

And these two facts, if anything, are what's going to allow the Chinese to roll over us economically in ten or twenty years. Not their sheer numbers, but their respect for education and their lack of muddying religious issues. They're intensely proud of their country and their accomplishments, which are indeed impressive, and that pride and ambition and ability will carry them a long way. Unless the US gets its priorities straight (more money for education, better pay for teachers, more access to quality education for everyone), we're soon going to be buying more than cheap tchotchkes, outsourced electronics, and pirated movies from China. We'll be importing technology we should have invented and produced ourselves.

all you need is the rocket experience

If you've been paying any attention here, you know what a huge supporter of space exploration I am. Manned missions to Mars, moon bases, shuttle flights, space tourism: I love it all. It's probably part of my love of travel; what could possibly be more different from home than another planet? Than outer space? My fascination also stems from an early love of science fiction and early indoctrination with Star Trek (I was 6 when the show first aired). But its simultaneity with the first moon landing (the original series ran from 1966-1969, in case you actually don't know this) was probably the clincher. Not only could we dream about going to other planets, but hey! We could do it! Nothing could be more inspirational to a kid than watching a dream come true, or in this case, watching people actually setting foot on an alien world, when all you've done is read about it or seen fictional stories about it. It gives one a "damn we're good!" feeling not to be rivaled or duplicated in any other way.

 This is one of the reasons I feel shuttle flights are so important: not just for the scientific knowledge that we gain with each one of them, but for their immeasurable inspirational quality. Having lived most of my life with the fact of my fellow humans flinging ourselves recklessly into space from right here at home, I can't imagine that not happening, or imagine having to look to, say, China, for the next exploratory manned rocket launch. I do think space exploration should be an international effort. Nothing makes us realize that we're all part of one world than seeing the big blue marble from lunar orbit. Yeah, CGI is a marvelous thing, but it ain't real. But with shuttles due to be retired and NASA opting for unmanned Mars landings, how do you inspire young people at home to get the kind of rocket fever so many of my contemporaries had?

Cue Snoop Dogg and Buzz Aldrin:

P.S. I'm still processing my China trip and working my way through the essays my students wrote on Science in China, but there will be future posts on those topics. I just figured it was about time I got back to work here.

China on my mind

Color me boggled! I was all set to write about ionizing radiation from your CRT (still in the works, I promise) and then I got some really cool news: I'm going to China for a month to teach English! Now, aside from being a great opportunity to see a new country, about which I (shamefully) know next to nothing, and meet new people, I have a hunch this will have some major ramifications for Cocktail Party Physics, or at least my contributions to it. Turns out the place I'm going to be teaching English is Harbin Institute of Technology, in Harbin, Heilong Jiang Province, 881 miles northeast of Beijing. I'm told by my grad school pal who was there last year that HIT considers itself the MIT of China. Whether it's got quite as many quirky and creative people as MIT remains to be seen, but I'm very excited to have the chance to interact with some of China's scientists. Cuz, it turns out, I'll be "teaching" the faculty sections. *gulp!* These are conversation classes, primarily, so I'm going to try to take a page from Jen's stint at KITP and focus on improving presentation skills, which I hope will give me a crash course on what kind of research is going on in China. Sadly, I'll be too far north to catch the total solar eclipse on July 22nd, but maybe we can take a field trip. That would definitely be cool!

As I said, what I don't know about China could and has filled volumes. What I know about science in China, well, I think the sum total probably involves gunpowder, printing presses, and paper, which is pretty pathetic considering how old China's civilization and technology are. (Although I'm pretty excited about the paper and printing parts, being a book and letterpress nut.) Jospeh Needham wrote an exhaustive 7-volume history of science in China, but I'm not going to get to a fraction of it before I leave in July. A quick browse through Wikipedia (I know, I know; I'm slapping myself upside the head for you) gives me the compass, drydocks, the escapement mechanism, the first observations of a supernova, the first comet atlas, some wonderful feats of engineering not the least of which is the Great Wall , and extensive research in medicine and anatomy. This doesn't even begin to scratch the surface. I have a lot of background reading to do.

I think it's safe to say that one thing that sets Chinese science apart from western science, historically at least, is the lack of a unified scientific method. Science developed quite differently in China than it did in the west. Patricia Ryaby Backer explains it this way, in a text published by AAAS: "According to traditional Western scientists, the roots of science and the scientific method is in Greece and Greek thought. There is a tendency among scientists to claim that not only modern science, but science in general, was characteristic of European thought. The accompanying argument in that all scientific contributions from non-European civilizations were technology-based, not science-based (Needham, 1993)." In other words, it was the concept of the cosmos as a rational system that was unique to western science, and this sprang out of the Greek development of "Euclidean deductive geometry and Ptolemaic astronomy." This might, as Needham points out, be defining science far more narrowly than it can be defined. Certainly China was not without scientific developments, many of them far ahead of concurrent western technology. Certainly one of the things that helped science advance and grow in the west was the development of bodies like the Royal Society and the dissemination of information on experimental methods that led to a standard philosophy. In short, it's hard to separate the development and progress of science from the society in which it takes place.

And that said, it's hard to contemplate Modern China without thinking about Tienanmen Square. Today is the 20th anniversary of the pro-democracy protests that took place there, and the horrific images of a lone student facing down tanks have become iconic and representative in the same way photos of the Kent State shooting did, which is to say that every country has its repressive atrocities. In a country that values cooperation over individuality, it will be interesting to see how science happens. Teamwork is always important in research, but not infrequently it's an oddball out on a limb somewhere who comes up with real innovations. Or maybe that's just my personal prejudice speaking. I'm looking forward to having more data with which to form more complete conclusions.

Since I'm conducting conversation classes, I'll need conversation topics. Are there things that you'd like to know about Chinese research or even Chinese culture in general? Send me your questions and ideas and I'll work them into the conversation and the upcoming blog posts.

le fleur ephemeral

Some folks might find the purpled prose of Edgar Allan Poe a trifle overwrought by today's standards, but he's experienced a mysterious resurgence of popularity in the last couple of years. He's been the subject of two historical literary mysteries (Matthew Pearl's The Poe Shadow, Louis Bayard's The Pale Blue Eye) and historic "true crime" tomes like The Beautiful Cigar Girl, about a famed NYC murder case in the 19th century that captivated Poe and inspired his short story, "The Mystery of Marie Roget." I've read all three, and quite enjoyed them, but there's really no substitute for the original short stories by the master himself. Serendipitously, I found myself re-reading "The Cask of Amontillado" (written in 1846) after the Spousal Unit and I returned from our trip to Paris last week. (He was attending a cosmology workshop, I tagged along as a spousal adjunct. Because it was Paris, people! No way I'm staying home with the cat!)

Anyway, in the big climactic scene of "Cask of Amontillado," the protagonist, Montressor, walls up his enemy inside a cavity hidden deep within some catacombs. Poe describes them as being "lined with human remains, piled to the vault overhead, in the fashion of the great catacombs of Paris." You can see where I'm going with this. I was in Paris. There are catacombs in Paris. I'm a Poe fan. How long do you think it took for me to ferret out the entrance to the catacombs from our little boutique hotel in the Latin Quarter? (Our hotel boasted the Smallest Elevator in France. Seriously, I thought at first we'd been directed to the dumbwaiter by mistake.)

Well, I mapped it out on the plane ride over, but waited until the Spousal Unit could join me for the excursion itself -- last Friday, when his workshop was all but over. In the interim, I killed some time visiting the Picasso Museum; Notre Dame Cathedral; the Pantheon (where all the famous French atheists are buried, so really, one must pay one's respects); the Museum de Cluny du Moyen Age (which features The Lady and the Unicorn tapestry, as well as being built around the ruins of a Roman bath); wandering around the banks of the Seine (it's a most walkable city); and getting all turned around in the Dutch masters wing of the Louvre before finally locating an exit. The catacombs were by far my favorite sight, and well worth the wait.

I've long been a fan of Parisian history, particularly anything to do with the French Revolution and the era of The Man in the Iron Mask and The Three Musketeers (as in the novesl by Dumas, not the chocolate bar), and the film version from the 1970s starring Michael York as D'Artagnan was awesome. But I'd never really thought about the vast network (stretching some 300 kilometers) of subterranean tunnels  and caverns under its quaint streets strewn with boutiques, cafes and boulangeries.

The catacombs are pretty much abandoned limestone mines, that limestone having been removed to build a goodly part of the city. Miners have been burrowing into the ground and creating tunnels since at least the 12th century, digging ramps and vertical well shafts as needed to reach the desired minerals and other deposits buried there -- not just limestone and clay, but also gypsum, the origin of plaster of paris. There were occasional surprises: in the 19th century, diggers uncovered the remains of a Roman-era clay mine. Less welcome surprises were the occasional collapses, the most major of which occurred in 1774 along the route de Fontainebleu. That tragedy led to the formation of a special division of architects to inspect, repair and otherwise maintain Underground Paris.

But what to do with the abandoned mines once their reserves had been depleted? It just so happens Paris had another problem -- overcrowding in its cemeteries -- that reached a crisis point in the late 17th century when the largest cemetery, Les Innocents, had to be condemned. Mortality rates were pretty high back then, after all. The last gravedigger there, Francois Pantrain, apparently buried 90,000 bodies in his 35-year tenure. We're talking centuries of bodies piling up in cemeteries all over the city, so many that the ground levels in many churchyards had risen a good 20-30 feet because of the added volume from all those human remains. It was a health hazard: improper burials, open mass graves, and all that decomposing organic matter leaking into the ground led to widespread disease. (The Spousal Unit swears there was a notorious flood in which bodies were unearthed and flooded the city streets, but I couldn't find any record of this in my admittedly brief Google search.)

Clearly something had to be done, and a police lieutenant general hit upon the idea of storing the cemetery remains in the now-abandoned quarries, or catacombs. So the ground was duly consecrated and between 1786 and 1788, Les Innocents was slowly emptied of human remains. Bodies were moved at night in a strange ceremonial procession of tipcarts laden with corpses (discreetly covered by a black veil) accompanied by priests chanting the burial service en route. And hired laborers undertook the thankless task of organizing all those decaying bones for tidy storage. It had to have been tedious, unpleasant back-breaking work, but at least the laborers could indulge in some macabre whimsy while painstakingly stacking human femur bones -- separated occasionally by decorative "borders" or grinning skulls -- to build side walls in the vacant cavities that once held limestone and gypsum. There's a Jolly Roger design made of bones, and a heart pierced by an arrow.

It was an enormous undertaking, so perhaps the city planners can be forgiven for the cavalier manner in which the bones were deposited into their new home: no attempt at maintaining individual tombstones or properly cataloging specific remains. All the bones were just mixed and mingled, noblemen with paupers. (Death truly is the Great Equalizer; we all eventually meet the same unceremonious fate.) Okay, they tried to be somewhat respectful of the remains. Once all the bodies had been relocated, mass was celebrated to honor the now-anonymous dead at a specially constructed altar bearing a rather dour inscription: "Man, like a flower of the field, flourishes while the breath is in him, and does not remain nor know longer his own place. In peaceful sleep rest great people." There are lots of plaques with inscriptions throughout the ossuary, in several different languages, all pretty much sounding the same basic theme: everything you think is so damned important in life amounts to nothing in the end, when everyone, great and small, is reduced to the same pile of dry bones. My personal favorite was a poetic medication that essentially said that life and all its trappings merely constitute le fleur ephemeral (the ephemeral flower). It sounded way cooler in French.

There's some interesting geophysics (avalanche dynamics, for example) and engineering to be found in the Paris catacombs. The constant risk of collapse led to the development of techniques to shore the walls up a bit by injecting concrete in them as reinforcement, and this also gave rise to a couple of impressive, bell-shaped galleries with curved "roofs" some 11 meters high. They're known as "bells of subsidence" (the most famous is the Cloche de Fontis). Abandoned quarries erode in a very specific manner, it seems: first the "ceiling" of a lower level tunnel collapses a bit, and since the just ground above now has little support, it too collapses into the quarry. This process continues over time, resulting in "walls" that are constantly reinforced with sprayed liquid concrete to prevent further collapse, until they almost reach street level.

Parisians certainly weren't the first to conceive of burying their dead in underground chambers. The Etruscans did it, too, along with many other European peoples. It's quite practical, actually, apart from the whole occasional caving-in thing. The Romans preferred cremation (at least early on), but the urns were stored in a columbarium. After  2 AD, the unburnt remains were stored in graves or sarcophagi. Gradually the Roman catacombs fell out of favor for funereal arrangements, in favor of traditional cemeteries. The rise of burial as a custom might be attributed in part to the spread of Christianity. When your religion espouses the bodily resurrection of the dead, you're a bit more reluctant to destroy the physical outer shell that remains after death.

The Roman catacombs were carved out of the soft rock typical of the terrain outside Rome's official city limits by fossors (excavators). These catacombs are probably famous as those of Paris: there's at least 40 known catacombs, usually named after saints or martyrs believed to be buried there, lost amid the vast network of galleries and passageways (ambulacra). Some of the catacombs are four stories deep. Graves (loculi) were carved out of the walls, often containing more than one body. Wealthier sorts usually opted for an arcosolium in which to bury their dead, a kind of curved niche enclosed under a carved marble slab, or cryptae -- chapels decorated with frescoes and sealed off. They're mostly abandoned these days, apparently: not only were the Roman catacombs ransacked by Vandals and various Goths during the sacking of Rome, and by the 10th century AD most of the relics had been moved to above-ground quarters.

Ransacking has a way of rendering such marvels of engineering and architecture to the footnotes of history -- at least temporarily. The Roman catacombs lay dormant and forgotten for a good 500 years until they were rediscovered around 1578. A man named Antonio Bosio spent decades exploring and researching them -- a kind of ballsy thing to do, considering their labyrinthine nature -- and compiled his vast accumulated knowledge into one big seminal volume, Roma Sotterranea (Underground Rome), published in 1632. They've been studied and carefully preserved ever since, currently by the Salesians of Don Bosco, as agents of the papacy. That's what Wikipedia tells me, anyway.

Czechoslovakia boasts its own famous osteo-attraction, the Sedlec ossuary, in which workers of the past assembled the scattered bones into recognizable objects: a huge chandelier, for example, made up of each of the 206 different bones found in the human skeleton. That would be quite the conversation piece and Jen-Luc Piquant would totally have one in the Cyber-salon of her dreams. We share an appreciation for that kind of morbid playfulness exhibited not just in the Sedlec ossuary and the Paris catacombs, but also in the grotesque tableaux of preserved corpses that were the forte of Honore Fragonard. (We blogged about him previously here. Before there was Body Works, the museum exhibit -- now on display in Los Angeles -- there was Fragonard.)

Then there's the painted plaster skulls and skeletons, and preserved corpses on almost theatrical display in the Oratorio di San Lorenzo, a tiny Baroque-style church in Palermo, Italy. Unlike the Paris catacombs, the Palermo skeletons still have bits of flesh clinging to the bones, and the monks charged with maintaining the place have garbed them in period clothing -- albeit clothing that is also engaged in the long, slow process of decay. Somewhere on the premises, it's even possible to view the colatoio (colander), where the "soft matter drained away from the fresh corpse through the stone slats, leaving the parts of the body which the dressers would be able to work with."

That last sentence is from this article ("The Museum of the Dead") by Robert Harbison in Cabinet Magazine (h/t: 3 Quarks Daily) describing his (rather negative) impressions of the Palermo corpses: he finds the arranged bodies strangely compelling, but also dismisses the spatial layout as "monotonous," and observes, "It seems a minimal space, stripped bare of all pretense that what lies ahead is anything but grim." Different strokes for different folks, I guess, but for all the macabre nature of the display, there's something as strangely beautiful and somberly meditative about the Palermo corpses (at least as far as one can tell from the astonishing photographs published in Cabinet Magazine) as there is about the Paris catacombs -- perhaps because they still retain some vestige of the human beings they once were. They are not (yet) stacks of anonymous bones.

I can only assume the Palermo corpses have been carefully preserved by both natural and artificial means, thereby prolonging the process of decomposition. Fellow forensics buffs will know that the first stage involves the production of vapors -- usually pretty foul-smelling and giving rise to bloat -- followed by the solid flesh gradually melting into an icky viscous liquid (putrefaction). Exposing a body to air will speed up this process (not to mention bring increased "insect activity" -- Grissom would heartily approve!), while buried bodies can decompose as much as eight times more slowly, depending on the composition of the soil and surrounding temperature. The final stage is dry decay (diagenesis), in which the bones, now stripped of all soft tissue, begin to dry out and deteriorate. It can take a very long time to complete this stage and reduce the bones to ashes. Basically, the protein-mineral bonds in the bonds weaken and organic protein starts leaching away.

The bones in the Paris catacombs are noticeably dry and brittle, clearly well on their way in the process of decay, although they won't be disappearing completely into ash any time soon. Today, the remains of some 6 million Parisian remains are housed in the Paris catacombs. Walking through the corridors is like getting a stark visual representation of just what 6 million bodies looks like (and, among other things, reinforces the horror of events like the systemic extermination of 6 million Jews during World War II). But there's nothing garish or exploitive about the catacombs. Instead, there's a kind of hushed reverence in their dimly lit passageways. Somehow the macabre flights of whimsy and dour plaques on the futility of life strike a perfect balance: the catacombs are respectful of human life and death, but not in a way that trades on glorifying (now long-forgotten) individuals; the focus is on the universality of death. Even men who were sworn enemies during the French Revolution find themselves sharing crypt space in the catacombs. There's a strange beauty in that. We are all, ultimately, just les fleurs ephemeral. And that's not necessarily a bad thing to be.

let it snow

My last evening in Seattle, I was hanging out at a local Starbucks in Renton, a suburb just south of the city. So engrossed was I in my work, that I failed to notice it had begun to snow. In less than an hour, a good three inches had accumulated, and it didn't show any sign of stopping. Lacking snow tires on my rental car, I realized I'd never get back up the long steep hill leading to my folks' place (where I was staying), so I parked the car in a nearby corporate lot, and bummed a ride with a local guy named Joe who'd had the foresight to pack some chains in the back of his pickup. (Thanks again, Joe Whoever-You-Are; you spared me a mile walk in the snow.) It made the next morning a little stressful, given my noon flight back to DC. I had to dig out the car and gingerly navigate the by-then very icy side roads to the freeway -- which, mercifully, was dry as a bone. In fact, you'd never know people were stranded in the suburbs if you were driving on I-405, which might explain why Avis was so incredibly unsympathetic when I returned the car with only half a tank of gas, citing the inclement weather as an excuse.

Chalk it up to one of those weather flukes; it's been an unseasonably cold winter in Seattle, and the city does occasionally get a heavy snowstorm. But it snowed in Los Angeles this week! Los Angeles, people! As in, southern California, land of the orange groves, and my soon-to-be-hometown. (This year's crop went straight to orange concentrate, I'd wager.) Now that's an historic event! It reminded me of a scene in To Kill a Mockingbird, where  the little girl-narrator, Scout, sees pretty white snow flakes falling and assumes the world is ending. She's never seen snow before, since it's a very rare occurrence in rural Georgia Alabama. The world didn't end then, and it's not ending now, but it's just one more bit of evidence that weather is a very wacky thing.

Unless, like Scout, we've never experienced a genuine snowfall, we probably take snow a bit for granted. It's just another form of precipitation, after all, and we have a pretty solid grasp of that particular cycle. Just for the record, snow is not frozen raindrops; that would be sleet. Under certain conditions, water vapor can condense directly into tiny ice crystals, skipping the raindrop phase altogether, and usually forming the shape of a hexagonal prism (two hexagonal "basal" faces and six rectangular "prism" faces). But that crystal also attracts more cooled water drops in the air. Branchings sprout out from the single crystals' corners to form snowflakes of increasingly complex shapes. And yes, for all intents and purposes, no two snowflakes are shaped exactly alike, at least according to Caltech physicist Kenneth Libbrecht, who runs this Website devoted entirely to snow crystals. But there are 35 different types of snow crystals, all of which he has carefully documented.

Libbrecht must have been thrilled to see snow in Los Angeles, since he usually has to create his own ice crystals in the lab, or go to more frigid climes, like Michigan or Alaska or Ontario, to make his high-resolution microscope images of snowflakes. (You can see movies of lab-based snow crystals forming here.) Even then it's a tricky business. He has to use a small paintbrush to transfer the delicate structures to a glass slide, taking the picture with a digital camera mounted on a high-resolution microscope. All of this is done outside to keep the crystals from melting too quickly. The final images are quite striking -- so much so that last October, they were featured on a new 39-cent commemorative postage stamp, courtesy of the US Postal Service.

Not surprisingly, the shapes of snowflakes and snow crystals have long fascinated scientists, like Johannes Kepler, who took some time away from his star-gazing in 1611 to publish a short paper entitled "On the Six-Cornered Snowflake." He was intrigued by the fact that snow crystals always seem to exhibit a six-fold symmetry. Some 20 years later, Rene Descartes waxed poetical after observing much rarer 12-sided snowflakes, "so perfectly formed in hexagons and of which the six sides were so straight, and the six angles so equal, that it is impossible for men to make anything so exact." He pondered how such a perfectly symmetrical shape might have been created, and eventually arrived at a reasonably accurate description of the water cycle, adding that "they were obliged to arrange themselves in such a way that each was surrounded by six others in the same plane, following the ordinary order of nature." (The lack of a detailed explanation can be excused: it took the development of x-ray crystallography for scientists to really be able to study the shape and structure of snow crystals/flakes in any great detail.)

Libbrecht has an historical predecessor in Robert Hooke. Hooke's Micrographia, published in 1665, contained a few sketches of snowflakes he observed under his microscope -- sketched rapidly, one assumes, since the flakes no doubt melted soon after being placed under the lens, even working outdoors. If only he'd had access to Libbrecht's equipment, he wouldn't have had to do everything by hand -- and he would have appreciated the far more intricate details observable under orders-of-magnitude increases in resolution.

But nobody performed a truly systematic study of snow crystals until the 1950s, when a Japanese nuclear physicist named Ukichiro Nakaya identified and cataloged all the major types of snow crystals. (Nakaya had the bad luck to be appointed to a professorship in Hokkaido, with no available facilities for his nuclear research, so he applied his considerable skills to what was readily available: snow crystals. Now that's taking lemons and making lemonade.) He also proved Descartes wrong in the Frenchman's assertion that no man could make anything so perfect. Nakaya was the first person to grow artificial snow crystals in the laboratory. In 1954 he published a book on his findings: Snow Crystals: Natural and Artificial. Here's what Libbrecht's Website has to say about it: "Nakaya's book offers a superb look at a scientific investigation which begins with almost nothing, and proceeds through systematic observation toward an accurate description of a fascinating natural phenomenon."

Thanks to Nakaya's pioneering work, we now know that certain atmospheric conditions, like temperature and humidity, can influence a snowflake's shape. For instance, those shapes tend to be simpler in low humidity. The higher the humidity, the more complex the shape, and if the humidity is especially high, they can even form into long needles or large thin plates. Scientists aren't entirely sure why, but they suspect it has to do with the complex underlying physics of how water vapor molecules are slowly incorporated into the growing ice crystal -- what Descartes termed the "ordinary order of Nature." There's still a lot of mystery in that ordinariness.

That's why NASA has launched the Global Snowflake Network, a massive project that aims to involve the general public to  "collect and classify" falling snowflakes. The data will be compiled into a massive database, along with satellite images, that will help climatologists and others who study climate-related phenomena gain a better understanding of wintry meteorology as they track various snowstorms around the globe. Participating students, teachers, and other interested parties will have the chance to take part in real science, and learn more about how climate, temperature and other atmospheric features combine to produce weather phenomena.

So next time snow falls in your area this winter, take a few moments from building snowmen and lobbing snowy missiles at the annoying kid down the street, and look more closely at each individual flake. You might even consider signing up with the GSN, thereby recording your observations for scientific posterity.