Note (12/2015): Hi there! I'm taking some time off here to focus on other projects for a bit. As of October 2016, those other projects include a science book series for kids titled Things That Make You Go Yuck! -- available at Barnes and Noble, Amazon and (hopefully) a bookstore near you!

Co-author Jenn Dlugos and I are also doing some extremely ridiculous things over at Drinkstorm Studios, including our award-winning webseries, Magicland.

There are also a full 100 posts right here in the archives, and feel free to drop me a line at secondhandscience@gmail.com with comments, suggestions or wacky cold fusion ideas. Cheers!

· Categories: Physics
What I’ve Learned:

Nucleation: Once you start, you REALLY can't stop.
“Nucleation: Once you start, you REALLY can’t stop.”

Everybody has to start somewhere. If you’re a corporate lackey, you start at the bottom. If you’re a gravedigger, you start at the top. And if you’re a phase transition, you start with nucleation.

Phase transitions are the change of a substance from gas to liquid, or from liquid to solid. But transitions don’t magically happen everywhere at once; you never see a swimming pool full of water freeze in an instant.

Not outside of a Vegas Penn and Teller show, anyway. Preferably with David Blaine chained down in the deep end.

Instead, the process — in this case, the formation of ice crystals — starts in one or more places called nucleation sites. In pure substances, these sites may occur randomly; where materials are mixed or in an irregular container, the nucleation sites usually form where different surfaces meet. Like by a leaf floating in the swimming pool. Or the tip of David Blaine’s nose. Just for instance.

Once formed, the nucleation sites provide an anchor for the transition process. That process speeds up, piling onto the sites like tacklers on a running back, until the entire team is on the pig pile and the system comes back into equilibrium. In the example above, that would be when all the water on the surface that’s cold enough has frozen into solid ice. Or when they fish the David Blaine-cicle out with a pool noodle.

The magic-but-actually-science of nucleation is not limited to freezing water, however. It’s also a crucial part of other natural processes, like crystallization, cloud formation and elongation of biological polymers like actin filaments. Some quantum cosmologists have even hypothesized that our entire universe is the result of a sort of bubble nucleation in the vacuum of whatever it is that lies outside the universe we observe.

(My guess for what’s out there? That girl from the Wendy’s commercials. Because she seems to be every-fricking-where else these days.)

Speaking of bubbles, a lot of people have been having fun with nucleation, possibly without realizing it. The key to the explosive foaming mess you can make by dropping a Mentos candy into a bottle of diet soda is indeed nucleation. Small pores in the Mentos allow bubbles of gas from the soda to form, which attract more bubbles and more bubbles — and they tell two friends, and so on and so on until there’s foam all over your kitchen and mom’s asking why there’s half a dissolved mint embedded in the ceiling.

Of course, bubble nucleation doesn’t require all those theatrics to be useful. Microscopic irregularities in champagne glasses nucleate those nose-tickling bubbles in the bubbly everyone loves. Nucleation also explains why it’s harder to pour a beer into a used glass without foaming up the place; the remnants of the previous pint’s suds provide sites for bubble-making that a fresh clean glass would not.

So that’s nucleation in a nutshell. It’ll help you pour a good beer, it makes Mentos much more interesting, and it might help us get rid of David Blaine. Honestly, what more could you ask of science?

Image sources: ASEPTEC (nucleation diagram), YouTube (cold, wet but sadly unfrozen David Blaine), Examiner.com (football pig pile), New York Times (science ‘n’ Mentos)

· Write a comment
· Tags: , , , , , , , ,


· Categories: Biology, Genetics
What I’ve Learned:

Synthetic genomics: when regular old DNA just won't do.
“Synthetic genomics: when regular old DNA just won’t do.”

Genomics is the study of and the fiddling with (science term) an organism’s DNA. So naturally, you might think that “synthetic genomics” is studying and fiddling with DNA while wearing polyester.

It’s not. From what I’ve seen of most biologists’ wardrobes, the polyester thing is pretty much implied in all of genomics. And most weekend parties.

Instead, synthetic genomics is a particular style of fiddling with DNA that uses components and rules that nature hasn’t gotten around to trying yet.

(Because nature tends to be very busy doing other things. And in her spare time, distracted by all the polyester.)

There’s a big difference between sciences like “genetic modification” or “genetic engineering” and synthetic genomics. All sorts of organisms’ genomes have now been modified in the lab — corn, for instance, and glow-in-the-dark fish, and possibly Jocelyn Wildenstein. But in these cases, the genes engineered into the DNA came from other species in nature, and followed the usual rules for how DNA works.

(Not how faces work, necessarily. But at the DNA level, it’s all textbook. And usually a difference of just one or two genes.)

But synthetic genomics is different. Here, the usual rules go out the window. Recently, a team of scientists used computers to redesign a chromosome found in yeast, synthesized the new sequence and plugged it back into real yeast cells.

Why? I’m not entirely sure. Maybe they’re trying to create glow-in-the-dark beer, or sandwich bread that talks to you while you eat it. Both of which I’m in favor of — preferably in the same meal. But in the meantime, it’s a monumental bioengineering achievement, and could produce more efficient yeast.

No doubt the Pillsbury dough boy and Budweiser Clydesdales are salivating over that.

Another team is trying to modify pig DNA to look more similar to humans. Which, of course, because a real-life Porky Pig is an obvious choice to be the next judge on The Voice. But actually, it’s so pig lungs can be yanked out and transplanted to save humans with terminal lung disease, while eliminating the problem of foreign tissue rejection.

Which just goes to show, everything is better with bacon. Including cross-species thoracic surgery. Mmmmmm, bacon.)

The biggest news to come out of synthetic genomics recently is that the DNA inside every living thing — from bacteria to badgers to Barbara Walters — can be expanded upon. Improved. Turned to eleven.

Announced just this week, scientists at the Scripps Research Institute whipped up a strain of E. coli bacteria that don’t just use the usual four basic building blocks of DNA, but instead use six.

This is big news. It’s like when Columbus turned Europeans on to a whole new continent, or Lewis and Clark followed Sacagawea through the Northwest, or the day you discovered you like actually dark beer. Whole new frontiers open up, full of possibility and hangovers and grizzly bear attacks.

And now, full of semi-synthetic genetically-fiddled-with E. coli., like little microscopic scientists wearing polyester pants. Sometimes the bacteria don’t fall far from the tree.

In practical terms, an expanded DNA alphabet could lead to revolutions in genetics, bioengineering and the ability to mass-produce useful proteins that have never before existed.

Whether that will finally improve biologists’ wardrobes is still up in the air. Science can only do so much.

Image sources: ChemistryWorld (6-base DNA), NBC New York (Jocelyn Wild-n-woolly-stein), Broadway World and Popscreen (Porky and the Voice), Unstable Molecules (unfashionable scientists [Phil and Lem, awww])

· Write a comment
· Tags: , , , , , , , , , , , ,