First, however, some background. I’m a chemist (or used to be one), so I’m a super nerd when it comes to relativistic chemistry. It turns out that as elements get heavier, relativity becomes more and more important. As a theoretical chemist, one thing you learn quickly is that if you don’t take relativity into account, your calculation will be way off.

Without relativity, for example, my thesis work on IBr- had to take into account relativity. Iodine is a heavy element so relativity is important, so, I had to consider it. I did this the easy way: I let others take care of it! I used what’s called an ECP that sort of built in the relativity without my needing to worry.

I can hear you saying: so what, IBr isn’t that important and I’ve never heard of it. But, let’s say you want to calculate the what color gold metal should be or what mercury should be like at room temperature. Without relativity, gold looks like silver and mercury is a solid. With relativity, gold is gold and mercury is a liquid.

So now to the main event: why your car battery only works because of relativity. Couple  weeks ago, a paper came out in Physical Review Letters (PRL, 106, 018301 (2011) if you have access to it) by Pekka Pyykkö and collaborators called “Relativity and the Lead-Acid Battery”.  This paper uses relativistic quantum chemistry to model the reactions in a lead-acid battery (like the 12V battery in your car) and it found something rather amazing. Of the voltage generated by a lead-acid cell, which is ~2.1 V (there are 6 cells in a 12 V car battery), fully 1.7-1.8 V is due to relativistic effects. 80-85% of the voltage in a car battery is there because of relativity!

As the authors note in the paper, while the lead-acid cell has been known for 150 years, this paper is the first doing ab initio, or first principles, calculations, compared to the more modern lithium-ion cells of which ab initio calculations abound. The major reason for this is that lead is heavy and a heavy atom is a hard atom to calculate.

(They also show that without relativity, it’d make for a crap battery. They do calculations with lead’s lighter brother tin and find that a tin-acid battery wouldn’t be worth it’s weight in, well, tin.)

I just love it when something I studied, I’ve used, I know about has such a cool result like this.

Yours in NERD!,

Matt

My confusion is…why? Why couldn’t I just pour it into a half-filled tank and then fill the tank? It’s still one bottle of additive in one full tank.

My first thought is that maybe the additive isn’t very miscible, so it needs the physical action of the fueling to help mix? But, really, a fuel additive that isn’t miscible in fuel?

I suppose the real answer is that some yahoo had some overfilled gas tank and then added a bunch of flammable hydrocarbons to it and boom or something.

I dunno. Just irked me. Feel like they could just put “add to one full tank of gas”. But, well, we are the culture that came up with “Careful: Contents Are Hot” on a cup of coffee and all.

For many moons, I’ve been a member of both the ACS (American Chemical Society) and APS (American Physical Society), the former for ten or more, the latter for a few.  As a theoretical chemist, having a membership to these societies was quite useful. You get a subscription to a very good “popular” magazine, Chemical and Engineering News and Physics Today, discounted registration at conferences, and, perhaps most importantly, access to the respective job banks.

All this, though, comes at a cost. When you are a grad student and recent postdoc, the membership cost isn’t too expensive and the benefits well outweigh the costs.  But once you are a “professional member” the costs double–I think–at least to $140 and $118 per annum.

Okay, that’s not bad, not great, but not horrible. *But*, I am no longer a practicing chemist/physicist. I’m a code monkey. A membership to IEEE or ACM would make more sense, really. Heck, I’m kind of attending SC09, the supercomputing conference, next weekend.

But, but, but. I am a chemist. I am a physicist (according to Feynman, no less). I still think of myself as such and I suppose a part of me thinks one day I might be a practicing chemist/physicist again.

I’m not sure what to do.

The science-y part is that it does this by way of isopentane, a substance with the cool property that it boils right around room temperature (28 degrees C or so).  So, the isopentane is in the gel that is put in your mouth, which is at 37 degrees or so, and, voila, the isopentane boils causing the gel to get foamy!  I imagine the heat generated by the friction of brushing helps move things along as well.

Right now I’m trying to figure out any cool demos or something that I can do to have fun with gelled isopentane.  Everything I think of seems to use equipment I’d have in a chem lab, but not at home.  But, then again, are a Bunsen burner and a gas range really that far apart?

The answer, by the way, is yes! A thousand times yes! Don’t use a gas range burner as a Bunsen burner! Sigh…time to find a lawyer…

If you like, the whole of Lilavati’s Daughters can be found at the IAS’ website here. Some of the autobiographical essays that I’ve read–and I haven’t read them all–are just great.  So good, in fact, that I’m thinking I might buy the book (available from Scholar Without Borders). Sure there is a slight (okay, whopping) premium over the base price of Rs300 to get it here, but $25 is worth a great book. Plus, I suppose I see buying a book like this as a show of support for women in science.

Even if they are all usually smarter than me. Damn you, nerds of the fairer sex!

Yours in women in science,

Matt

They present you with an image or images from a paper, some text, and then ask you a question about it.  Most of the time, you don’t need to read the paper to know the answer if you have a reasonable chemistry background.  But, that doesn’t mean to say you’ll always get it right.  What you can be sure of, though, is that you’ll usually go “Oh yeah…” when you get one wrong.

For me, the current challenge (#35 as of writing), is one that is pretty easy for me.  And, I suspect, for just about anyone.  But, some are a bit out of my field, like biochem or inorganic. I can give a slightly educated guess, but random might be more effective for this theorist.  But, it is JACS: you get theory, experiment, analysis, everything, all in one journal.

Plus, sometimes you get a really cool one. Looking back to recent ones, there is #30 where you get a fun video of some rather impressive science.  Or, there is #31 which, after answering, you find that most visitors actually get it wrong (myself included). And, thus, I learned something new!

Still, that is no reason not to start again.  So, I’ve been adding papers, and I noticed something that just bothers me. When you add a paper to CiteULike, you get to “rate” your…enthusiasm about the paper.  From “Top priority!” (5 stars) to “I might read it” (2 stars), it’s all good.  But then you get to “I don’t really want to read it” and that gives it one star.  That one star seems…odd to me.

To me, one star still means it’s a paper I want to read.  Maybe it’s in astronomy or some field I don’t know much about, but if I’ve taken the time to press the CiteULike button and save it to my “library”, it seems like the least amount of interest would be “might read it”, not “not gonna do it”[1].

[1] If you heard Dana Carvey when you read that, you are old. I wrote it, so I know I am.

And if there was ever an issue of Contemp Phys to read this is the one.  It’s the 50th Anniversary Issue.

For those who’ve never read Contemp Phys, it’s a journal which is dedicated to making current, sometimes bleeding-edge, physics intelligible to a wider audience.  That often includes other physicists and, quite often, one certain theoretical chemist.

In this issue, you’ll find works by many of the big names of physics.  No, wait, this is Physics.  Names like Salam, Peierls, Hawking, and Chandrasekhar. But many of the articles are written by names just as big, just not as well known.  No matter what, though, ALL of the papers in this Issue are uniformly great.

That said, I was happy to see that one of my all-time favorite papers was included.  This is Otto Frisch’s famous “Take a photon…” paper. In this paper, Frisch presents a series of Gedankenexperiment (thought experiments) as a dialogue between various characters in regards to the interference of a single photon.  If you love great quantum physics, this is the paper for you.  If you love the freakiness of quantum mechanics, this is for you.  Heck, if you are interested in the quantum computing and information, one of modern physics’ big fields, this is a paper for you.

But, really, all of the papers in this issue (and remember there is a second page of papers…which isn’t quite apparent on InformaWorld’s site) are for you.  Read them all.  You will learn something in one of them. Probably in all of them.