When a post-doc joins your group, you’re never sure exactly what you’re going to get. I’ve known both good ones and some not-so-good ones. The following is a story about one of the latter, whom I met during my graduate school days in Illinois.
He was not in my group, but belonged to a research group whose lab space I was sharing. The post-doc, whom I shall call Dr. Orange (only members of the group would understand the significance of that nickname), was from Sweden. His area of expertise was multinuclear NMR of transition metals and that was exactly what the professor desired. Everything seemed to be working out okay with Dr. Orange, until he was asked to prepare some sodium decavanadate (Na6V10O28) for some simple V51 NMR measurements. It is a rather simple prep. You basically dissolve some vanadium(V) in water and manipulate the pH until beautiful orange crystals fall out of solution. I had made this stuff years before as an undergraduate and hadn’t had a problem. Unfortunately this prep was beyond Dr. Orange’s capabilities. Either the crystals failed to appear, or they appeared and then disappeared, or if they stayed around long enough to be filtered, the crystals would quickly decompose. (I think he had neglected to rinse his fritted glass filter after a sulfuric acid washing). I volunteered to do the prep myself, but the professor said no, that it was Dr. Orange’s responsibility.
Things started to turn ugly and he began blaming other members of his group for sabotaging his synthesis. For example, he was sure the now-you-see-them-now-you-don’t crystals had been stolen. He believed someone had actually gone through the trouble of filtering out the crystals when he was away, throwing them out (he was convinced he found a trail of orange drops leading to a wastebasket), and then returning everything back the way it was. Of course, he also thought his labmates were stealing his mail too. Rather paranoid if you ask me. Eventually the professor instructed Dr. Orange not to make any more accusations and to just finish the damn prep. We later discovered that the guy had gotten his PhD mostly by grabbing compounds off the shelf, or synthesized by other people, and running them through an NMR. He didn’t know much about chemicals themselves.
Of course, an NMR jock doesn’t have to be good at synthesis, as long as the NMR jock is good with NMRs. Unfortunately, Dr. Orange was not. He was given permission to use the departmental multinuclear NMR, but that ended just as badly as the decavanadate prep. He could never get the instrument to shim properly, he had trouble understanding the software, his spectra were often ugly, and he managed to somehow wipe out the entire operating system. Along with everyone else’s spectra. Twice. That’s a lot of angry grad students. After the second data wiping, he was only allowed to use the instrument during the day, and only under the supervision of one of the NMR techs. You can imagine how embarrassing this was to the professor who had hired him. Besides, all the best NMR data is taken after midnight anyway.
He disappeared at the end of the year, much like his crystals.
Friday, August 28, 2009
Tuesday, August 11, 2009
Back on the Air Again
Here’s hoping that my long hiatus from blogging is about over. I returned from my Grand Canyon trip several weeks ago, but I just spent the last two weeks in Missouri with my family. After a long battle with Parkinson’s disease, my father passed away last week. He taught me a lot about life and I’ll miss him. Who knows how my life would have turned out had not my parents bought that chemistry set for my birthday back in grade school? Thanks for everything, Dad.
In a lighter bit of news, my wife came across Mythbusters the other night, a television show dedicated to proving or disproving various myths, commonly accepted beliefs, and stunts enacted on TV. I haven’t seen many episodes, but in this one the hosts were attempting to reenact a scene from an old MacGiver show, where MacGiver used the sodium+water reaction to blow up a masonry wall. Chemical experiments on TV? Okay, I’ll watch for a while. Unfortunately, anyone who has ever handled sodium would know the small piece of sodium which they were using (duplicating the MacGiver episode) was doomed to failure. I threw larger pieces than that into buckets of water back in high school. (Not that that means it’s a particularly smart thing to do, I might add). The safety precautions used by the show’s hosts were a little over the top, but then again, I don’t know how much experience these guys have with chemicals. When the sodium failed to make more than a loud noise, they eventually turned to using potassium (which is much more reactive) while also increasing the amount of metal to 500 grams. The explosion was more impressive visually, but as expected, the wall wasn’t even touched.
Of course the reason why sodium or potassium explodes is due to its reaction with water to form hydrogen and heat, which then proceeds to ignite with the oxygen in air. Despite the rather impressive sound produced by hydrogen explosions, the actual explosive force is rather low, unless large quantities are present (or if one tries to constrain it within a vessel that might shatter). Two summers ago, my kids attended a demonstration where hydrogen and air were bubbled through dishwashing soap to create a pile of foam which was scooped up by the demonstrator and ignited while still clinging to his hand. Impressive noise, but no damage to the fingers. Now I’m not knocking the potential dangers of hydrogen here. After all, I work on fuel cells, and we pipe pure hydrogen all over the lab, so our detection and alarm systems are quite elaborate, let me assure you. But hydrogen is usually only a problem if large amounts of it collect somewhere, like near the ceiling, which is why hydrogen detectors are always placed up there.
Hydrogen explosions are interesting in that most explosives, such as TNT, work because their ignition produces a huge volume of gas (much of it carbon dioxide) which rapidly expands. The combustion of hydrogen
H2 + 0.5O2 ----> H2O
actually results in the loss of ½ molecule of gas, which might be expected to create an implosion instead, except that the large amount of energy released during the reaction heats the gas, causing it to expand rapidly per the ideal gas law. The thing that makes hydrogen particularly dangerous is its extremely fast flame propagation speed, which allows all the hydrogen to react nearly simultaneously, greatly increasing its explosive power.
I didn’t watch the whole show. Can anyone tell me if they were successful in making a working hang glider using the motor from a portable cement mixer?
In a lighter bit of news, my wife came across Mythbusters the other night, a television show dedicated to proving or disproving various myths, commonly accepted beliefs, and stunts enacted on TV. I haven’t seen many episodes, but in this one the hosts were attempting to reenact a scene from an old MacGiver show, where MacGiver used the sodium+water reaction to blow up a masonry wall. Chemical experiments on TV? Okay, I’ll watch for a while. Unfortunately, anyone who has ever handled sodium would know the small piece of sodium which they were using (duplicating the MacGiver episode) was doomed to failure. I threw larger pieces than that into buckets of water back in high school. (Not that that means it’s a particularly smart thing to do, I might add). The safety precautions used by the show’s hosts were a little over the top, but then again, I don’t know how much experience these guys have with chemicals. When the sodium failed to make more than a loud noise, they eventually turned to using potassium (which is much more reactive) while also increasing the amount of metal to 500 grams. The explosion was more impressive visually, but as expected, the wall wasn’t even touched.
Of course the reason why sodium or potassium explodes is due to its reaction with water to form hydrogen and heat, which then proceeds to ignite with the oxygen in air. Despite the rather impressive sound produced by hydrogen explosions, the actual explosive force is rather low, unless large quantities are present (or if one tries to constrain it within a vessel that might shatter). Two summers ago, my kids attended a demonstration where hydrogen and air were bubbled through dishwashing soap to create a pile of foam which was scooped up by the demonstrator and ignited while still clinging to his hand. Impressive noise, but no damage to the fingers. Now I’m not knocking the potential dangers of hydrogen here. After all, I work on fuel cells, and we pipe pure hydrogen all over the lab, so our detection and alarm systems are quite elaborate, let me assure you. But hydrogen is usually only a problem if large amounts of it collect somewhere, like near the ceiling, which is why hydrogen detectors are always placed up there.
Hydrogen explosions are interesting in that most explosives, such as TNT, work because their ignition produces a huge volume of gas (much of it carbon dioxide) which rapidly expands. The combustion of hydrogen
H2 + 0.5O2 ----> H2O
actually results in the loss of ½ molecule of gas, which might be expected to create an implosion instead, except that the large amount of energy released during the reaction heats the gas, causing it to expand rapidly per the ideal gas law. The thing that makes hydrogen particularly dangerous is its extremely fast flame propagation speed, which allows all the hydrogen to react nearly simultaneously, greatly increasing its explosive power.
I didn’t watch the whole show. Can anyone tell me if they were successful in making a working hang glider using the motor from a portable cement mixer?
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