JOE PALCA, host:
And now that moment you've all been waiting for, when we talk about the Video Pick of the Week, which is not frictional but fictional - no, not fictional but frictional.
FLORA LICHTMAN: Right.
PALCA: Here with us is Florida - Florida. Flora Lichtman. She's the digital media producer for SCIENCE FRIDAY. Hi, Flora.
LICHTMAN: Hi, Joe.
PALCA: So what part of the friction story are you telling us this week?
LICHTMAN: Well, from fingerprints we're now going to snake bellies…
LICHTMAN: …and the friction caused by the scale. So this story goes back 50 years, when biologists looked at how snakes slither. And the common thinking was, well, snakes are on the forest ground, right, and there are trees and rocks, and they push their body against these big objects.
PALCA: Makes sense.
LICHTMAN: But the question remained: What - how do snakes move on smooth surfaces?
PALCA: So which smooth do you mean? Like the polished marble floors of the snake kingdom in the middle of the jungle or…
LICHTMAN: It doesn't have to be quite that smooth. I mean, still, you know, a desert or hard rock.
PALCA: Right. Something that wouldn't have a lot of bumps to push on through.
LICHTMAN: No debris, right.
PALCA: Right. And so the answer is, drum roll…
LICHTMAN: Right. Well, Dr. David Hu, who's at Georgia Tech, has - I think has an answer, and that is the scales provide sort of traction. And he did a lot of experiments and published them in the Proceedings of the National Academy of Sciences this week about sort of getting to the bottom of this question.
PALCA: So you really have to go to the Web site because you can - you can go to your mailbox and get your copy of the Proceedings of the National Academy of Sciences, but what you can't get unless you go to the - you'll probably get it other ways - but one way to get it is the actual pictures. These are really hilarious - unless you're a snake - pictures of a snake on a very smooth surface. And in fact, they don't go very fast when the surface is completely still.
LICHTMAN: I thought it was pretty amazing. Actually, I hadn't considered that if you put a snake in a smooth surface it really can't slither. It's worth a look, I think.
PALCA: It is. And even better than that - and I can't imagine anyone who wouldn't want to see this - you can see two things. One is snake in a sock.
PALCA: And - but even better than that, I think, is a snake in Jell-O.
LICHTMAN: Yes. That's right. It's a classical biological technique for understanding force, apparently, so they say.
PALCA: So they say. And that's what I love. When you look at the grant application and you have the budget line for, you know, $15 for boxes of Jell-O and your grant examiner says, are we joking here or what? Well, that's science for you. Okay, Flora, sounds great. Thanks very much.