Make: Online: Chemistry Archives

Archive: Chemistry

February 9, 2010

UC Berkeley has "Nobel Laureate Only" parking spaces

jonathan_fiamor_nobel_laureate_parking_at_UC_berkeley.jpg

Image courtesy Jonathan Fiamor Photography.

When I was at UT Austin, a school which is famously car-unfriendly, it was rumored that one of the elder patriarchs of the College of Natural Sciences--a man who had multiple doctoral degrees and had been given countless awards for his work both as a scientific researcher and an educational administrator--had once quipped that the honor that was most valuable to him, on a daily basis, was the "O" parking permit that let him leave his car literally in the shadow of UT's iconic tower.

Well, in terms of available parking, UC Berkeley makes UT Austin look like an airport remote lot in Iowa on a Wednesday in the dead of winter. And according to this official page there are presently seven living Nobel laureates on the faculty there, so I'm guessing there must be at least seven of the prestigious NL parking spaces. Supposedly, regular mortals have to shell out $50 for presumptuous malparkage among the elite.

February 8, 2010

Glenn Seaborg's old mailing address

The occasion of Dmitri Mendeleev's birthday seemed like a good opportunity to recognize another great hero of the periodic table and to relate one of my favorite anecdotes about him: Glenn T. Seaborg (Wikipedia), who, among his various stellar achievements, won the 1951 Nobel Prize for "discoveries in the chemistry of the transuranium elements." By the time of his death in 1999, Seaborg had participated in the discovery and isolation of ten superheavy elements. Shortly after the official 1997 recognition of the name seaborgium for element 106, Jeffrey Winters, writing in the January 1998 issue of Discover Magazine, made the following observation:

Not only is Seaborg the first living scientist to have an element named after him, he's also the only person who could receive mail addressed only in elements: Seaborgium, Lawrencium (for the Lawrence Berkeley Laboratory where he still works), Berkelium, Californium, Americium. But don't forget the zip code.

Naming an element after a living scientist generated significant controversy among the international chemistry community of the time. At a talk in 1995, Seaborg himself famously quipped: "There has been some reluctance on the part of the Commission for Nomenclature of Inorganic Chemistry of the International Union of Pure and Applied Chemistry to accept the name because I'm still alive and they can prove it, they say."

Maker Birthdays: Dmitri Mendeleev

Born on this date in 1834 in the small village of Aremzyani, in what was then considered Siberia, Dmitri Ivanovich Mendeleev (Wikipedia) would go on, in 1869, to publish the first periodic table of the chemical elements. Mendeleev used the periodicity he'd observed in the properties of then-known elements to accurately predict many of the properties of germanium, gallium, and scandium, which had not yet been discovered. Mendeleev died in St. Petersburg in 1907, at the age of 72. Element number 101 is named mendelevium in his honor.

Brilliant red dye made from insects

Photo courtesy Flickr user Scoutj.

This article just drew my attention to the interesting story behind carmine, which is a pigment precipitated from carminic acid (shown below) extracted from the bodies of Dactylopius coccus, the so-called "cochineal" insect, of which the acid comprises up to 24% of dry body weight. The cochineal is a parasite of cacti of the genus opuntia, from which it has been harvested in South America since pre-Columbian times. It is carmine that produced the "red" of the famous British "red coats," and today carmine is still produced in great quantity for use in fabric, cosmetics, and as a natural food coloring. (Vegans beware!) [via Neatorama]

February 3, 2010

Flashback: The Florence Siphon Arabica Brewing & Extraction Apparatus

I thought I was really into coffee until I met John Edgar Park, host of Make: television, contributing writer to Make: Online, and author of several MAKE magazine articles. John takes his coffee seriously. Seriously. Case in point was when he devised and wrote a how-to for his Florence Siphon Brewing and Extraction Apparatus for MAKE Volume 17, our Lost Knowledge issue. This apparatus is sure to raise eyebrows (and spirits) next time you invite someone to your workshop for a cup of blessed joe. Check out the whole project in this week's Flashback, and pick up a back issue of MAKE 17 over in the Maker Shed.

Make your own mad-scientist coffee machine.
By J. Edgar Park II

Aboard the dirigible Aeroship Phaedrus, two men are seated at a table in the onboard Laboratory:

"Doctor Liepold, would you kindly prescribe something to lift my depressed spirits?"
"Why of course, Captain Heffernan. What is it that ails you?"
"My mind feels sluggish and there is still much work to be done before daylight. I am drawing up charts for the expedition."
"Ah, yes, I have just the thing. Sit a moment while I extract the invigorants from these wondrous beans."
"Very good, thank you. What is that strange device, Herr Doktor?"
"I call it the Florence Siphon. It is an arabica brewing and extraction apparatus. Allow me to demonstrate. First, I fill this boiling flask with a quantity of pure spring water. It is a vessel of my own devising that can withstand great heat and pressure. I heat the flask, which causes the water to vaporize, passing through this tube here, through a filter, and into the beaker to my left. Here, the water commingles with precisely roasted and ground fruit of Coffea arabica. I give the slurry a rapid stirring to fully saturate the grounds, then wait.
"As my boiling flask cools, a vacuum is created, causing the very atmosphere of the Earth to push the liquid through the filter, leaving the grounds and all unsavory particulate matter behind. Thus the liquid, now filled with essences, oils, solubles, flavors, and vital invigorants, is returned to the flask. Allow me to unstopper it and pour you a dose."
"Doctor! You have outdone yourself! I feel revitalized by this most miraculous potion."

The vacuum siphon coffee brewing method dates back to the 1840s. It produces some of the cleanest, smoothest-tasting coffee of any method. Commercial vacuum pots are available, but I wanted to heighten the drama of vacuum brewing by taking it into the realm of the mad scientist's lab. Thus the Florence Siphon was born!

After studying original patent drawings and existing devices, I identified these key features:
• Water is heated in a boiling flask that has a tube leading to a second vessel containing ground coffee.
• The tube must have a filter, to allow the water to flow through but not the grounds.
• The filter must be submerged during brewing, so as to maintain a seal with the boiling flask.
• The second vessel must be accessible for stirring the slurry.
• The boiling flask must be large enough to create a sufficient vacuum as it cools to "pull" the coffee back through.

One drawback to early vacuum brewers was the constant danger of exploding glass. Today, we have plenty of high-quality borosilicate glassware that's up to the task — it just happens to be found in the lab, not the kitchen.

Filtration was another challenge. I tinkered with a few options (including an unfortunate foray into shower heads) before arriving at an inverted thistle tube. This is a type of bulbed funnel that's easy to cover with filter cloth. (Thanks to Dr. Jim Callan from Avogadro's Lab Supply for this suggestion.)

I assembled my funnel, stopper, tubing, filter, and a beaker for the grounds. I filled my flask with preheated water (small burners can take a while to boil 500ml), poured 38g of medium-ground coffee into the beaker, donned my goggles, and lit the burner.

The water began to bubble quickly, and soon went straight up the glass tube and over to the grounds. After about a minute, the flask was nearly empty and I extinguished the flame. At this point, there was an abundance of expanded water vapor (steam) inside the flask, which prevented the water from returning.

I stirred up the slurry with a stick and then waited with great excitement. Would the siphon be able to draw the coffee back up? At just about the 2-minute mark, I saw the gorgeous brown liquid begin its ascent. This is due to the vacuum created by the cooling and contraction of water vapor in the boiling flask. It was tentative at first, but as the boiling flask continued to cool, the coffee started to move quickly up the tube, over and then back down to the flask below. Within another 20 seconds, the journey was complete: 420ml of coffee made it back, leaving 80ml of water behind with the grounds.

I removed the stopper and poured myself a cup. It was perfect! Smooth, bright, clear, and clean. Vacuum coffee is a step above a French press, and leagues above drip. Plus, when you brew with the Florence Siphon you get to don your lab coat and cackle maniacally. What more could you want from a cup of coffee?

Here's how to build your own Florence Siphon.

February 2, 2010

Mercury "beating heart" works with gallium, too

So it turns out, happily, that the mercury beating heart demo I wrote about a couple days ago can also be done with molten gallium, which is vastly less toxic than mercury and requires only slightly higher temperatures. The chemists at the University of Nottingham who produce The Periodic Table of Videos made this very informative footage demonstrating the process, which is slightly different from the mercury beating heart demo in that there is no iron nail present. The gallium blob "beats" anyway, but much slower than the mercury with the nail. I bet using a nail would make the gallium version beat just as fast. [Thanks Filip!]

January 31, 2010

Briggs-Rauscher oscillating chemical reaction

Discussion about yesterday's mercury "beating heart" reaction post got me thinking about chemical oscillators in general. Turns out, the mercury beating heart may be the only mechanically oscillating chemical reaction that anybody knows about. It's certainly the only one I know about, and its the only one I can find on the web. But if you know of another mechanically oscillating reaction, do please drop me a comment. However...

January 30, 2010

Mercury "beating heart" demo video

This classic chemistry demo involves the use of toxic metallic mercury, so it's one of those that is best to just watch on YouTube instead of trying yourself. The pulsing action is caused by surface tension effects--metallic mercury is oxidized at the surface of the drop to form a film of mercury (I) sulfate, which lowers the drop's surface tension and causes it to flatten under its own weight. The flattening brings the drop into contact with the tip of a carefully-positioned iron nail, which reduces the mercury (I) sulfate back to metallic mercury, which in turn increases the drop's surface tension and causes it to contract away from the nail. The solution contains an electrolyte and an oxidizing agent, in this case weak sulfuric acid and potassium dichromate, respectively. Thanks to YouTuber sciencevidds for sharing it with us. [via Boing and then some more Boing]

January 28, 2010

Hydrogel is mostly water, but strong as silicone rubber

I am always on the lookout for cool cutting-edge chemistry for my Make: Projects series. It doesn't happen often, but occasionally there's a breakthrough that's both interesting and important, and yet easy enough that even non-professionals can replicate it in their kitchens. It's one of my dreams to someday present a home chemistry project based on science just published, within the preceding week, in one of the major journals.

January 26, 2010

Journal of Serendipitous and Unexpected Results

This dude is Hans Christian Ørsted, whose 1820 discovery that electric current produced magnetic fields was, supposedly, entirely accidental: He was preparing a voltaic pile for a lecture demonstration and there happened to be a compass lying nearby. He has become a sort of mascot for the Journal of Serendipitous and Unexpected Results (JSUR), a new open-access journal initiative that hopes to provide a forum for life and computer scientists to publish results they lucked into and maybe can't fully explain. From their website:

Can you demonstrate that:

* Technique X fails on problem Y.
* Hypothesis X can't be proven using method Y.
* Protocol X performs poorly for task Y.
* Method X has unexpected fundamental limitations.
* While investigating X, you discovered Y.
* Model X can't capture the behavior of phenomenon Y.
* Failure X is explained by Y.
* Assumption X doesn't hold in domain Y.
* Event X shouldn't happen, but it does.

JSUR is now accepting manuscripts for their first issue. [via Boing also Boing]

January 25, 2010

Cocktail blueprints for engineers

These detailed technical drawings for various cocktails were first created, per the revision log, by one RJ DININO in 1978, and most recently updated by one J GOTTA in 2008. You can download a printable PDF at FlowingData. [Thanks, John!]

January 24, 2010

Make: Projects - Periodic table elements collection cabinet

Every chemist (and arguably every scientist, and arguably everyone else in the world), whether amateur or professional, should have an elements collection. Theodore Gray has written eloquently about the hows and wherefores of collecting the chemical elements, so I won't belabor the point here other than to say: chemistry has been called the central science, and arguably, chemistry's greatest achievement has been the discovery of the chemical elements, the realization of the periodicity of their properties and its implications for atomic structure, and the isolation of each of those elements in its pure or "standard" state. Collecting the individual elements lets you participate in that incredible story in a way that no amount of book-learnin' ever will.

January 22, 2010

New catalyst turns atmospheric CO2 into useful chemical

Anyone who suggests that we might fix the atmospheric carbon problem just by recycling carbon dioxide from the air and turning it into, say, plastic, probably hasn't run the numbers: the 3% human contribution to annual global carbon dioxide emissions is 23 billion metric tons, whereas annual global plastics production amounts to only 91 million metric tons. Even if the necessary technology were practical, in other words, the entire annual global human plastics demand would consume less than 1% of the entire annual global human carbon dioxide surplus.

Still, every little bit helps, and this copper-based catalyst recently developed by Elisabeth Bouwman and co-workers at Leiden University in the Netherlands represents a vast improvement over previous atmospheric carbon-dioxide-fixing processes. Most of these are poisoned by oxygen, which means that you can't just pump air into the reactor without removing the oxygen first. Bouwman's catalyst, however, reacts with carbon dioxide but not oxygen, producing oxalate, which is a useful feedstock for the manufacture of methyl glycolate and other organic compounds. And while Bouwman's material is not a "true" catalyst in that it actually forms a compound with carbon dioxide and has to be regenerated in a second reaction, the regeneration step can be done electrochemically with remarkably little energy.

Here's the abstract of Bouwman's recent paper in Science, and here's an audio interview with Bouwman from the Science podcast.

January 21, 2010

Beautiful 'silk frost' fibrous ice formations

Dr. James Carter is a professor in the Department of Geography-Geology at the University of Illinois. One of his many interesting pages collects photos and other reports (dating back to 1884) of so-called "hair ice," "haareis," or (my fav) "silk frost." The fibrous ice crystals seem to be caused by the pore structure of certain woods, and only forms where the bark has been removed. Reportedly, the phenomenon is reproducible: if you find a piece of wood growing hair ice, you can warm it up, then re-freeze it, and it will grow hair ice again. [via Neatorama]

January 20, 2010

Maze-traversing oil drops

Physical chemist Bartosz Grzybowski and colleagues at Northwestern University have created a microfluidic system that solves mazes like a lab rat. The system is very simple--besides the maze itself, there's the dyed drop of acidic oil that actually traverses the maze, the basic hydroxide solution that fills the maze, and the acidic lump of agarose gel that marks the maze's exit--but results in an apparently complex behavior. The droplet at right actually took a couple of wrong turns and back-tracked to correct them. [via Neatorama]

January 16, 2010

Make: Projects - 15-minute ice cream with a dry ice bath

Photos by Maya Chavez-Akin.

Making ice cream with cryogens stronger than water ice is a fairly common chemistry demonstration stunt. The ideal way to do it is with liquid nitrogen, which is poured directly into the ice cream mixture, with stirring, and causes it to set up in about 10 minutes. Liquid nitrogen, however, can be rather difficult to get your hands on. Most major cities have a supplier that will sell it to you, but very often they have large minimum orders and/or require that you own an expensive dewar flask into which they may safely dispense the liquid nitrogen. At -196 C, liquid nitrogen is also fairly dangerous to handle.

Dry ice is a much more accessible cryogen; it's available at several major grocery stores in the Austin area, for instance, and I imagine the same is true in other parts of the United States. It sublimes at -78 C, and is thus vastly more effective at freezing stuff than water ice at 0 C. You can make ice cream, just as with liquid nitrogen, by adding dry ice directly to the ice cream mixture. However, because dry ice is frozen carbon dioxide, this procedure results in carbonated ice cream. Which can be quite delicious. But say you don't want carbonated ice cream?

This procedure borrows from a common technique in the organic chemistry laboratory for cooling reactions to sub-zero temperatures. Instead of using ice water to cool to 0 C, you make a bath of dry ice in some volatile solvent that will not freeze at dry ice's sublimation temperature of -78 C. Obviously, you can't use dry ice in water because the water will freeze solid. In the laboratory, acetone and isopropyl alcohol are common coolants. Acetone, however, can be dangerous if handled improperly, and isopropyl alcohol in sufficient quantities to make a large bath can be rather expensive.

I have discovered, however, that denatured ethanol, which is available in hardware stores everywhere, is reasonably priced and makes a good bath with dry ice. Denatured alcohol is also much safer to handle than acetone. Depending on the denaturant, it is also the least toxic of the various hardware-store solvents. In any case, done with reasonable care, this procedure involves no significant risk of contact between the ice cream itself and the coolant. And although denatured alcohol is quite flammable, the dry ice temperature of -78 C is well below its flash point at 13 C, which means that, once the bath is cool, there is no danger of the alcohol vapor igniting from a stray spark. To err on the safe side, however, you should be sure to work in a well-ventilated area.

January 15, 2010

Alt.CES: I can haz hydrogen?

On the assumption that hydrogen-powered cars (jet packs?) will be commonplace some day, H-hawker Horizon introduced a consumer gadget at CES that converts water into hydrogen and stores it safely in solid form.

The small desktop device simply plugs into the AC, a solar panel or a small wind turbine, automatically extracts hydrogen from its water tank and stores it in a solid form in small refillable cartridges. The cartridges contain metallic alloys that absorb hydrogen into their crystalline structure, and release it back at low pressures, removing concerns about storing hydrogen at high pressure. This storage method also creates the highest volumetric energy density of any form of hydrogen storage, even higher than liquid hydrogen. Unlike conventional batteries, these cartridges carry more energy capacity, are cheaper, and do not contain any environmentally-harmful heavy metals.

Horizon believes the HYDROFILL is the first step towards private refueling of new generations of fuel cell electric vehicles. Fuel cell technology can greatly improve the features and usability of many battery or engine-powered devices, and create the possibility for lower cost electric cars that drive longer distances and recharge instantly.

[via electronics-lab.com]

January 11, 2010

Alternative representations of the periodic table

The periodicity of properties of the chemical elements has been represented many, many different ways since Mendeleev. The modern standardized periodic table is only one of a potentially infinite number of graphical representations of the empirical trends. If you understand the logic of the periodic table, looking through these "alternative" representations can be a lot of fun. There are hundreds of them! [via Boing Boing]

January 7, 2010

Atomic-bond resolution microscopy

Pardon me while I go chemistry geek. It has recently come to my attention that Leo Gross and co-workers at IBM Research in Switzerland have developed a special atomic-force microscopy technique that can image actual molecules with enough resolution to "see" individual bonds and hydrogen atoms. Shown uppermost is a computer-generated model of the pentacene molecule, and below it, an actual image from the microscope. The microscope's probe is tipped with a single molecule of carbon monoxide. Unbelievable.

January 6, 2010

Edible Lasers

A friend of mine claimed you can make a laser from a gin & tonic, and so I had to find out more. It turns out that not only can you make a very poor laser using ethyl alcohol, you can also make one from Jello! Well, not the actual Jello like you'd find in a grocery store - instead it would be a non-toxic variation of the traditional dye laser held in gelatin rather than liquid -- but edible and lasing none-the-less!

Stephen Wilk explores these and more edible possibilities in this article for Optics & Photonics News (embedded magazine reader). Alternative source: (google docs)

See also: DIY Pickle Light