JUANA SUMMERS, HOST:
It's time now for our science news roundup from Short Wave, NPR's science podcast. I'm joined by the show's two hosts, Regina Barber and Emily Kwong. Hi, all.
REGINA BARBER, BYLINE: Hey.
EMILY KWONG, BYLINE: Hey, Juana.
SUMMERS: So I know that you've brought us three science stories that caught your attention this week. Tell us what they are.
KWONG: Yeah. OK. So we have a scuba-diving lizard breathing by bubble charm.
BARBER: How adding on your fingers is a good thing for little kids.
KWONG: And how an ingredient in Doritos may help scientists see through skin.
SUMMERS: I have just a lot of questions about all of these. But I want to start with these lizards with scuba-diving capabilities Emily, what's up with those?
KWONG: OK. So first, what's neat about lizards is that they breathe like we do, through their lungs, including the water anoles. They're found in the tropical forests of southern Costa Rica. Water anoles are green brown in color, and they have stripes to hide from predators.
LINDSEY SWIERK: Water anoles are kind of like the chicken nuggets of the forest. They're less than the size of a pencil, and they're eaten by so many things in the forest.
BARBER: And several years ago, Lindsey Swierk, an assistant research professor at Binghamton University, observed a water anole dive under the water to hide from predators for 16 minutes.
SUMMERS: That is such a long time.
BARBER: Yeah.
SUMMERS: How did they do it?
KWONG: OK. Yeah. So Lindsey and several researchers have learned that upon diving, these anole exhaled a bubble of air around their head and kept it in place, Juana. So the bubble basically allows them to breathe. It appears as the anole exhales and disappears as inhales.
SUMMERS: OK, OK. I think I'm getting it. So was this bubble, then, helping them stay underwater for longer, like, I don't know, a scuba diver and their oxygen tank?
BARBER: Yes. OK. And to test this, Lindsey and her team covered the skin of a bunch of anoles with this emollient, which prevented the bubble formation. The study published this week by the Royal Society found that untreated lizards that could still blow bubbles stayed underwater 32% longer than the ones with the anti-bubble coating on their skin.
SUMMERS: OK. This is so interesting, but, like, help me understand big picture why this matters.
KWONG: Yeah. So it's of real interest to herpetologists, to lizard scientists, like Earyn McGee. She's behind the #FindThatLizard campaign on social media. Earyn said the last few years of bubble research have made her curious about whether anoles have underwater predators, too.
EARYN MCGEE: When the lizards dive in to avoid their terrestrial predators, do they at any point become fish food?
BARBER: And fundamental science like this is how a lot of cool discoveries get made. Lindsey says that maybe if we study null skin or bubbles even more, it could inspire some, like, biomaterials or other innovations to help humans someday.
SUMMERS: Interesting. OK, I want to move on to your next topic, which is about how kids add up numbers. Gina, is it helpful to use our fingers?
BARBER: Yeah. And a new study suggests this, but that hasn't always been taken as fact. I talked to lead author Catherine Thevenot. She's a cognitive developmental psychologist at the University of Lausanne in Switzerland. And she said, in the past, some instructors had frowned upon kids using their fingers to count.
CATHERINE THEVENOT: Did you know children? They used to hide their hands under the tables.
SUMMERS: OK. I have to admit this never really made a whole lot of sense to me, given that I, a full-grown adult, still sometimes use my fingers when I'm doing simple math. So why was it discouraged to teach this method?
KWONG: Yeah. I do the same thing. I still use finger counts.
BARBER: Yeah, me, too.
KWONG: So educators apparently were worried that if they taught kids to add with their fingers - one, two, three - that that would hold them back, and they wouldn't learn how to add without their fingers, or they would take longer to add.
BARBER: But this new study suggests otherwise. Like, researchers recruited 328 kindergartners from all over France, and a little over half of them were trained in finger counting, and the rest were not. And they found that the kids who learned finger counting did better on the calculation problems than the kids who did not.
KWONG: And it seems, Juana, that finger counting gave these kids a deeper understanding of what numbers are. So Catherine's advice for parents out there who see their kids counting on their fingers is...
THEVENOT: If you are a parent or a teacher, do not discourage them to do that.
SUMMERS: Seems a little definitive. So is that it then, counting with your fingers is just a better way to teach arithmetic?
BARBER: Well, not entirely. I talked to a cognitive psychologist who wasn't involved in this study, David Barner from the University of California San Diego. And he says, yes, this study does show finger counting helps kids solve math problems, but he's more cautious about what this means for class curriculum.
DAVID BARNER: This isn't grounds for changing what people are doing. This is evidence that finger counting is one way, but it's not evidence that it's the best way.
KWONG: He makes the point that in this study, finger counting doesn't differ significantly from rote memorization. So he suggested people teach kids both.
SUMMERS: For our third topic, we've got an unexpected scientific use for the same dye used in Doritos. OK, Gina, you've got to help me understand this one.
BARBER: Yeah. I love this. So you know when you eat Doritos and the dust just ends up everywhere?
SUMMERS: Uh-huh (ph).
BARBER: Yep. And scientists have figured out how to make this annoyance turn into something like a really cool tool. It turns out that the dye used in Doritos and other snacks, like candy corn and Mountain Dew, can help mouse skin turn transparent. And just to give you an idea, it's not quite like seeing through glass, but you can definitely see the mouse's organs. So researchers could study the mouse's insides all without harming it.
SUMMERS: OK. Listening to you explain this, I'm really curious. How did these researchers figure all of this out?
KWONG: It's so bizarre and cool. OK. So we talked to one of the researchers, Zihao Ou. He's a physics professor at the University of Texas in Dallas. He said, usually, we can't see through skin because when light waves hit the skin, the tissue scatters the light, so the skin appears opaque.
BARBER: But when the researchers rubbed a solution of the same yellow dye used in Doritos on the skin of a mouse's belly, it reduced that light scattering, and they could see through the skin. Zihao says he's really excited about the potential applications of this.
SUMMERS: So tell us what those are.
KWONG: Well, you know, if you think about it, Zihao says, looking directly at tissue without removing it, as in the case with the mouse belly, could be medically significant. Like, this could help scientists study something like chronic illness.
ZIHAO OU: We think this can change a lot of the biomedical research - for example, developmental and disease studies, especially cancer and aging diseases, where you need to monitor the developmental process for a long time.
BARBER: We also spoke to Scot Kuo, the director of the microscope facility at Johns Hopkins. He was not involved in this study, and he says that often, scientists have to use invasive techniques for this kind of research, but this method could help avoid that.
SUMMERS: Interesting. OK. But what about use in, say, human Dorito lovers like us?
(LAUGHTER)
KWONG: Yeah. Zihao said they'd need to test this to see if it could be safe for humans or if it would work at all on human skin, which is much thicker. And Scot told us researchers would also need to figure out how to get this technique to work on more-pigmented skin.
BARBER: But who knows? Maybe the future of science really does live in that Dorito dust on your fingers, which you could use to count things.
SUMMERS: This is such a wild, fun rundown of science news story.
BARBER: Thank you.
SUMMERS: Thanks, as always, for sharing, y'all.
KWONG: Oh, thank you, Juana.
BARBER: Yeah. Thank you.
SUMMERS: And one last thing before we go - I have heard you have a small plug for Short Wave's fifth birthday.
KWONG: Yes. For our fifth birthday, we are taking questions entirely from 5-year-olds. So if you're 5, to submit, record a voice memo with your name, location and question, and email that voice memo to shortwave@npr.org.
SUMMERS: Looking forward to hearing from all of those 5-year-olds.
BARBER: Yes.
SUMMERS: Thank you to Emily Kwong and Regina Barber from NPR's science podcast Short Wave, where you can learn about new discoveries, everyday mysteries and the science behind the headlines. Thanks to both of you.
BARBER: Thank you, Juana.
KWONG: Thanks, Juana.
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