All the Best Bits » chemistry

We Are What We Drink

Phillip Alvelda — Tue, 26 Feb 2008 15:22:00 +0000

Cerling and Ehleringer over at the University of Utah just published a paper in the online journal “Proceedings of the National Academy of Sciences” describing their new forensic technique, which uses Hydrogen and Oxygen isotope concentrations from local water tables in your hair to determine where you have spend your time.

The two maps here show predicted average hydrogen (top) and oxygen (bottom) isotope levels in human hair across the continental United States — isotopes that vary with geography because of different isotope levels in local drinking water. The ratios of heavy, rare hydrogen-2 to lighter, common hydrogen -1 are highest in red and orange areas in the top map, and lowest in the blue and darker green areas. The ratios of heavy, rare oxygen-18 to lighter, common oxygen-16 are highest in red and orange areas of the bottom map, and lowest in the blue and darker green areas. Credit: University of Utah

“You can tell the difference between Utah and Texas,” Ehleringer says. But, Cerling adds, “You may not be able to distinguish between Chicago and Kansas City.”

So in case you’re considering a life of crime, you might want to

Consider a new bald or buzz-cut look so the encoded travel history you carry along with you is limited.
Drink only bottled water
Shelve any green tendencies and eat at only imported meat and produce.

The "Dog’s Nuts" of the Periodic Table

Phillip Alvelda — Sun, 21 Oct 2007 15:54:00 +0000

Shelly Batts over at Retrospectacle just turned me on to this great show called Brainiacs. Here are a couple of fine videos starting off with a bit on alkali earth metals. I think Shelly is right, a British accent does lend an air of legitimacy. Kind of. Ahem. Don’t try this at home.

Try a YouTube search on Brainiac for more.

Great Bubble Demos and Formula

Phillip Alvelda — Thu, 18 Oct 2007 23:16:00 +0000

Several people have asked me recently about bubble solution formulations that improve on the regular dish soap stand-by. Take a look at this video to see some truly resilient, and even self-healing bubbles, along with the complete formulation!

Go forth and study bubble science!

A Photographic Periodic Table

Phillip Alvelda — Mon, 13 Nov 2006 15:26:00 +0000

I was talking to a friend from MIT a few years back, when she told me about this guy she used to date and what an incredible geek he was. Given her own tenure at MIT and her resultant accrual of a rather high level of nerd pride, it was indeed noteworthy to hear her cast such aspersions.

She went on to say “…he had even spent years collecting samples of most of the elements in the periodic table, and built a display case to hold them in the same layout.” Though I didn’t share it at the time, my first thought was “geeky or not, I would love to see it…maybe even build one of my own…” So I guess I’m a geek too.

What partly set off my imagination at the time, though, was the fact that the elements seemed very abstract to me when we first learned about them in high school chemistry. It wasn’t until decades later in my technical career when I had been exposed to all the uses and applications of the different elements that there was any physical grounding for the abstract table. A little extra time studying the applications of the elements, and a physical sample of each one seem like a capital idea!

I never did manage the meeting or the initiative to build my own collection, but now I can get pretty close with a lot less effort. Check out this photographic table of the elements.

(click on the image for an enlarged version)

I particularly like the titanium turbine blade, the hydrogen in the nebula, and the neon bulbs for the noble gases. I’d still like to see more examples per element, including things like integrated circuits for silicon and aluminum and so on. But at least it’s a start.

You can get all the posters and place mats you want here. Every chemistry classroom should have one!