Bill Nye discusses the 2 things that make “science” what it is. Then, you’ll learn about how female tree frogs have noise-canceling lungs; and why your stomach growls when you’re hungry.
Bill Nye discusses the 2 things that make “science” what it is. Then, you’ll learn about how female tree frogs have noise-canceling lungs; and why your stomach growls when you’re hungry.
Additional resources from Bill Nye:
This frog has noise-canceling lungs by Cameron Duke
Why your stomach growls when you're hungry by Ashley Hamer (Listener question from Safin in Lisbon, Portugal)
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/science-is-a-process-and-bill-nye-explains-why
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about the 2 things that make “science” what it is, with actual science guy Bill Nye. Then, you’ll learn about a frog that has noise-canceling lungs; and we’ll answer a listener question about why your stomach growls when you’re hungry.
CODY: Let’s satisfy some curiosity.
What you’re about to hear is, in my opinion, the most impactful segment you may ever hear on this podcast. You know how nobody really wants to admit when they’re wrong? Well SCIENTISTS admit when they’re wrong… all the time. If you think of science as just cold, hard, unchanging facts, then you need to hear this clip from our conversation with a so-called “science GUY” named Bill Nye. Here’s what he told us when we asked him if there’s anything that other people believe that he thinks is true (or vice-versa). Take a listen.
[CLIP 5:43]
Like Bill Nye said: science is 2 things. Yes, it’s a body of knowledge. But it’s also a PROCESS. It’s the way we know nature, the way we sort things out as humans. So the next time you hear that our understanding of something has radically changed, whether it’s the existence of a planet or what we know about a virus like COVID-19, stop and step back for a minute. And try to appreciate that you’re seeing science working the way it’s supposed to. Again, that was Bill Nye, and you can find links to pick up his latest book — or listen to his podcast “Science Rules!” — in today’s show notes.
For a tree frog, being able to hear the calls of potential mates is incredibly important. But female tree frogs have a tiny problem: noise. They have to be able to pick out the best call from a cacophony of noise. This is no easy task. Their solution? Noise-canceling lungs.
Scientists call this the cocktail party problem, and it’s one we’re all familiar with. It’s tough to have a conversation at a party when the music, the ice machine, and the voices of the other guests drown out the person you’re trying to focus on.
Female green tree frogs (hyla cinerea) deal with this problem all the time. They listen for the calls of their ideal mate, but he’s easily drowned out by the calls of other species and just general background noise. Luckily for the lady tree frog, she can tune everything else out by taking a deep breath.
When her lungs are inflated, they press against her eardrums. That changes their acoustic properties. Her eardrums become less sensitive to the calls of other species by dampening any unnecessary frequencies, which effectively tunes them out.
When the researchers measured the frequencies that the frog’s eardrums responded to, they found that the effect is much more nuanced than it would be if she simply plugged her little frog ears. They used lasers to measure the frequencies at which the frogs’ eardrums vibrated, and at what intensity. And they found that the effect was less like turning down the volume knob on your stereo and much more like turning down the bass and treble. The frequencies left unaltered are the frequencies the male tree frogs typically use in their calls. The researchers think that the frog’s lungs might act as a resonance chamber: they may create frequencies that destructively interfere, or cancel out, certain other frequencies. That’s pretty much how noise-canceling headphones work!
The researchers then looked at citizen science data to find out which frog species breed at the same ponds as the green tree frogs in their study. They found that the frequencies most dampened were the ones that other species tend to use.
So when there is a chorus of frogs all competing for attention, female green tree frogs can take a deep breath and the other calls just fade into the background.
We got a listener question from Safin in Lisbon, Portugal, who writes: “Why does our stomach growl when we are hungry? Is hunger the only cause of the sound?” Great question!
Technically, your stomach doesn’t only growl when it’s hungry — it also growls when it’s full. See, the muscle contractions that cause that growling are happening all the time. The noise is just louder on an empty stomach.
Those muscle contractions are a digestive mechanism called peristalsis [PARE-iss-STALL-sis], and they’re what help your food travel through the gastrointestinal system. After a meal moves down your esophagus, it sits in your stomach, which churns it up and breaks it down with digestive acids. Next, the food heads into the small intestine, which adds enzymes that help your body absorb the nutrients. Then it moves on to the large intestine.
Peristalsis happens in every one of these organs, just in different lengths and frequencies: in the esophagus, the contractions come in one long wave that lasts about nine seconds; in the small intestine, it happens more randomly: a few inches or centimeters here, a few feet there, at about 8 to 10 contractions per minute.
Peristalsis in the stomach depends on whether it’s full or empty. When it’s empty, contractions happen about three times per minute, and usually multiple contractions happen at different places in the stomach. When it’s full, those contractions get softer and slower, but they don’t stop altogether — that food has to leave the stomach eventually, after all. That’s one reason you don’t hear as much grumbling when you’re full. Another reason? The same as why tapping on an empty tin can makes more noise than a full one: food muffles the sound, but a stomach full of nothing but air helps the sound travel.
Thanks for your question! If you have a question, send an email or a voice recording to curiosity at discovery dot com, or leave us a voicemail at 312-596-5208.
Leave us a voicemail at 312-596-5208!
CODY: Before we recap what we learned today, here’s a sneak peek at what you’ll hear next week on Curiosity Daily.
ASHLEY: Next week, you’ll learn about why you forget things when you walk into a room;
How researchers designed a robot that reached the deepest part of the ocean;
Why throbbing pain has nothing to do with your pulse;
A counterintuitive way to get people to be less defensive;
And more! Okay, so now, let’s recap what we learned today.
[ad lib optional]
CODY: Today’s stories were written by Cameron Duke and Ashley Hamer, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Today’s episode was produced and edited by Cody Gough.
CODY: Have a great weekend, and change your mind about something. Be like a scientist. Just, please don’t change your mind about joining us again Monday to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!