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!

Wild Type


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

Wild type: tame on the outside, tamer on the inside.
“Wild type: tame on the outside, tamer on the inside.”

You would think the term “wild type” would describe the craziest, wackiest, furthest-out-there members of a species. Teen wolves. Mutant carny folk. Donald Trump.

But no.

In genetic terms, “wild type” refers to what you’d find “in the wild”, meaning the usual, most common, textbook examples. The ho-hummers. Been there, seen that.

When biologists describe things as wild type, they’re typically referring to one of two things: genotype or phenotype. The words look and sound nearly the same, but there’s an easy way to keep them straight:

Genotype starts the same way as “gene”, and indeed refers to DNA sequence, where genes live. A wild type genotype is one that matches the sequence most commonly found in the population. So what are you called if you have a different sequence, and your genotype varies from the norm? A mutant.

Not in a bad way, necessarily. But a mutation — either in one of your cells, or in one of your ancestors’ cells which was passed on to you — is how variation gets into genetic sequence, and those variations are tremendously important. Without mutations, we’d all have the same DNA. We’d all be susceptible to the same diseases. We’d have no flexibility as a species to survive. And we’d only have Teenage Ninja Turtles movies. Who the hell would watch those?

(Of course, according to Gattaca, we’d also all look like Jude Law and Uma Thurman. I’m sure there are downsides to that, somehow. I’ll let you know if I think of any.)

Then there’s phenotype, which starts with “phen”, so the easy way to remember that is “it’s not the ‘gene’ one”. Or make up something about “phenomenal”, maybe. Or “phenylalanine”. I don’t know. What am I, your mnemonics coach?

What phenotype refers to is outward appearance or traits. One or more DNA sequence changes (or genotypes) may lead to noticeable physical changes, or phenotypes. In fruit flies, for instance, there’s a gene that controls eye color. Certain genotypic changes, or mutations, in that gene lead to a phenotypic change: instead of beady little red eyes, the flies have beady little white ones.

Not as dramatic a physical change as you get from frappe-ing a fly’s DNA up with Seth Brundle’s, perhaps. But still, a distinctive phenotype — one for wild type, and one for mutants.

In the phenotypic sense, there is no single “wild type”. No one set of characteristics is standard, with offshoots of eye color and skin shade and curliness of hair radiating from it. You can compare variations to each other, but there’s no reference person or animal or bacterium to call ideal.

Likewise, you can come up with a “reference genome” for a species — and people have, for humans and fruit flies and rats and plants and plants and hundreds of other species. But each of these is just an average of the DNA that’s tested. One particular genotypic locus might have a certain sequence in fifty-one percent of the population, so it becomes “wild type”. But everyone else is then a “variant”, and none of us have the same set of millions of variants currently known. We’re all mutants, if you compare our DNA to the human reference genome, though we’re considered wild type in the majority of genomic positions.

Well, most of us are. Not counting Teen Wolf. Or carny folk. Or Trump. The only “wild type” of thing about them is their hair. Their scary mutant hair.

Actual Science:
Science Encyclopedia – Wild type
University of Miami – Wild type vs. mutant traits
The Scientist – GM mosquito cuts wild-type numbers
UCSC – The biology of the banana

Image sources: IJMM (wild type vs. mutant sequence), Geek History Lesson (Michael J. Wolf), Junkee (Teenage Wild Type Ninja Turtles), More Than Words (hairpiece with a Trump problem)

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Acoustic Levitation


· Categories: Physics
What I’ve Learned:

Acoustic levitation: be uplifted by the sound.
“Acoustic levitation: be uplifted by the sound.”

Imagine you found an insect in your bathtub — a beetle, say. And also imagine that you’re a kind and compassionate soul — or maybe you actually are, in which case bully for you, Gandhi — and you want to move the beetle outdoors without harming it. That’s where the situation gets a bit complicated, because:

You don’t want to grab the bug, because you might accidentally bend a leg or antenna or something.

Also, you don’t want to catch the bug in a box or glass, because that’s cruel — and we’ve already established you’re a tree-frenching envirohippie paragon. At least for the duration of this thought experiment.

And really, you don’t want to touch the bug at all, because it’s gross. I don’t care how you feel about Mother Nature’s skittering nightmares. Nobody’s touching them on purpose. Ew.

So what do you do? It seems like yelling at the beetle to get the hell out of your bathtime sanctuary wouldn’t help — but actually, it might. If you could yell in a very specific and consistent way, and get the insect in just the right spot, and also maybe have a machine do the yelling for you, to make it less stressful for everyone.

(After all, what did that disgusting little bug ever do to you, other than rubbing its filthy thorax all over your tub?)

If you could produce just the right sort of sound waves, at a high enough volume and a suitable frequency, you could actually lift that beetle off its porcelain perch into mid-air, without ever physically touching it. The process is called acoustic levitation, and can be a lifesaver for manipulating things you don’t want to touch. Even with a Kleenex.

Acoustic levitation — or sonic levitation, as it’s sometimes called — relies on the force of sound waves colliding with an object. Under normal circumstances, this force is tiny. It might nudge a few atoms around, but it’s too weak to get anything fancy accomplished.

However. If you concentrate enough sound waves together, then channel your inner Nigel Tufnel and turn the volume all the way up to 11, those puny nudges multiply into a force that can defy gravity — at least when applied small objects, like that bathtub beetle. Or a computer chip. Or an unstable chemical.

Of course, it helps to use “ultrasonic” signals — those outside the range of human hearing — lest you blast out your own eardrums trying to float a butterfly off your medicine cabinet. Typical volumes for effective acoustic levitation signals are 150 decibels and higher.

That’s basically the equivalent of listening to a NASA rocket launch from the comfort of a chair that’s been strapped to the bottom of the solid fuel booster. Or sharing an elevator with Donald Trump. But because human ears can’t “pick up” ultrasonic frequencies, we’re not deafened by the prodigious ruckus being created by acoustic levitation experiments. We’re also too big to be lifted off the floor by those experiments — and that’s where the beetles and other small objects come in.

There are many advantages to holding something in the air using only sound. Those computer chips, for example, could be examined — or even manufactured — with a complete panoramic view, and no worries about using electromagnetic forces for levitation, either. Chemicals can be mixed or tested without fear of breaking their container, because there is no container. And yes, maybe you could get an insect out of your bathroom without needing a desperate shower yourself.

Mostly, scientists are working on the computer chips and chemicals sort of applications for acoustic levitation. But maybe a beetle crawling up some egghead’s shower head will get them moving on the last one, too. We can only hope.

In the meantime, researchers have managed to move objects around with sound, too. With the right mix of frequencies, sources and intensity, levitated objects can be made to dance, move and travel around the acoustic field. This opens up huge possibilities for what acoustic levitation can do in fields from manufacturing to medicine. Maybe someday, we’ll all have kits that will float those bathroom beetles right out the window to freedom, No muss, no fuss.

In the meantime, I suggest yelling at the bugs as loud as you can. That might not get rid of them, but at least other people will probably come running. They’ll probably know what to do. Or at least bring a Kleenex.

Actual Science:
Wired – How do you levitate things with sound?
io9 – Yes, you can levitate objects with sounds
National Geographic – Scientists move levitating objects through space for the first time
Phys.org – Gravity-beating ultrasonic tweezers provide a sound route to bioengineering
Nerdist – Acoustic levitation is even cooler when it explodes stuff

Image sources: LiveScience (acoustically-levitated beetle), Cool Advices, Brooklyn Magazine (Nigel Tufnel, going to 11), Salon (Trump, mid-dump)

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