We love mountains!
Arseniy Rogov/Getty Images/iStockphoto
The ExPLORERR was built to go everywhere. That’s why this vehicle’s full name is: the Extremely Practical Land and Ocean Rover Exploring Remote Realms. And guess what? It has a recording studio built on-board! Good thing, because this episode was recorded while traveling up, up, up a mountain!
We discover some wildlife that lives at great heights as well as a rhyming ice cream salesman. Our pal and atmospheric scientist, Dr. Deanna Hence checks in to answer a popular question: if hot air rises, why is it so cold in the mountains? BRRRR! We also hear from NASA’s Dr. Dalia Kirschbaum, who has mountains of information about how mountains form.
Of course, there’s a fun Mystery Sound for you’re ears to explore! And lastly, but not leastly, our two new books came out today. Head to our books page to find out more about Road Trip Earth and Earth Friend Forever.
Audio Transcript
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BAXTER: You're listening to Brains On where we're serious about being curious.
DUMINKA: Brains On is supported in part by a grant from the National Science Foundation.
MOLLY BLOOM: OK, this star trip has been amazing. I can't believe we've traveled from the inner core of the Earth all the way to the moon. We've got so much great material for our new book Road Trip Earth.
SANDEN TOTTEN: It's been epic. People are going to love this book. And I can't wait to show everybody my road trip photos.
MOLLY BLOOM: Our road trip photos?
SANDEN TOTTEN: Well, they're mostly of me because let's face it, I'm everyone's favorite.
MOLLY BLOOM: You mean you are your favorites.
SANDEN TOTTEN: Exactly. But there's got to be one of you in here somewhere. Oh look, here. You can see the back of your head in this one.
MOLLY BLOOM: Well, that's something. Marc, how about we pull over all terrain, all planet vehicle to stretch our legs and replenish our snacks? We may be in the homestretch, but we still got a little ways to go.
MARC SANCHEZ: On it. Pulling over the Explorer a.k.a. the extremely practical land and ocean rover exploring remote realms. Look, I know, the whole point of an acronym is so I don't have to say the whole name every time. But it's so fun. Extremely practical land an ocean rover exploring remote realms. Extremely practical--
MOLLY BLOOM: Oh, Menaka is calling. Hi, Menaka. We miss you.
SANDEN TOTTEN: Menaka, did you get the last selfie I texted you?
MENAKA WILHELM: I did. As well as the other 37 selfies since we last talked.
SANDEN TOTTEN: Which is your favorite. It's OK to say all of them.
MARC SANCHEZ: Menaka, I can't wait to see you.
MENAKA WILHELM: I know. I'm so excited you guys are on your way back out. But I'm not just calling to say Hi. We have a bit of an issue here at Brains On headquarters.
MARC SANCHEZ: Oh, no. What's up?
MENAKA WILHELM: Well, Baxter just got here to record an episode with me.
BAXTER: Hi, guys.
ALL: Hey, Baxter.
MENAKA WILHELM: But when we got into the studio Bob was in there, and he had pretty much dismantled and alphabetized all the gear. It's going to take me at least a few hours to get it back into working order. I was wondering if I could have elevator drop Baxter off at the Explorer, and then you guys can record there.
MARC SANCHEZ: Oh, sure. I built a suite mobile studio in here too. Sending elevator our coordinates now.
MENAKA WILHELM: OK, awesome. Thank you so much. Oh, got to run. Bob, please stop alphabetizing. Maybe take a soup break.
MARC SANCHEZ: All right. Baxter should be here in 3, 2.
ELEVATOR: Here we are. The Brains On extremely practical land and ocean rover exploring remote realms.
MOLLY BLOOM: Thanks, elevator.
ELEVATOR: Happy to have a break from writing my memoir. The uplifting life of the world's smartest elevator. OK, bye.
MOLLY BLOOM: Hey, Baxter. So this was an episode about mountains, right?
BAXTER: Yeah.
MOLLY BLOOM: Well, this is perfect because there's a mountain right over there, and I think the top of it would be the ideal spot for a group photo to commemorate our road trip. Let's record the episode on our way up. That sound good?
BAXTER: Let's do it.
MARC SANCHEZ: All right, everyone. Buckle up. We have a mountain to climb.
[THEME MUSIC PLAYING]
MOLLY BLOOM: You are listening to Brains On from APM Studios. I'm Molly Bloom, and today we're broadcasting from the Brains On Explorer with my co-host Baxter from Camden, Maine. Hi, Baxter.
BAXTER: Hi.
MOLLY BLOOM: Thank you for joining us.
BAXTER: I'm always down for an adventure or up because we're going up a mountain.
MOLLY BLOOM: That's exactly what we like to hear. You wrote to us with a question about mountains.
BAXTER: Yeah, I want to know, if heat rises, then why is it so cold at the top of mountains?
MOLLY BLOOM: When were you inspired to ask that question? What made you think of it?
BAXTER: I think it was like one or two years ago when we were hiking up. I forget what mountain. I think it was someplace close to Camden, but I'm not sure. I asked that at the top of the mountain.
MOLLY BLOOM: It's a very good question. Where is the closest mountain to you where you live?
BAXTER: Oh, I could walk to it in probably 10 minutes.
MOLLY BLOOM: Oh, so you can see it from your house?
BAXTER: Yeah.
MOLLY BLOOM: When did you start hiking up mountains?
BAXTER: I've been hiking for quite a while. Even before I could hike, my parents were always hiking mountains while I was in a little backpack basically.
MOLLY BLOOM: So you've been like hiking mountains since before you could even hike yourself, you've been all over. That's awesome.
BAXTER: Yeah.
MOLLY BLOOM: So what is your favorite thing about hiking mountains?
BAXTER: It's just peaceful and it's repetitive and leaves you lots of times to just think about stuff.
MOLLY BLOOM: The mountain by your house that's so close, have you hiked up that mountain?
BAXTER: Yes, it's not that tall. It's like 1,000 feet or something straight up.
MOLLY BLOOM: That sounds tall to me.
BAXTER: But the tallest mountain that I think I've hiked is like 6,000 something feet.
MOLLY BLOOM: Wow. Yeah, mountains are amazing and I'm so glad someone with so much first hand mountain experience is here to help us answer the mountains of questions from our listeners all about these picture perfect peaks.
DIEGO: Hi, my name is Diego and I'm from San Francisco, California.
MAYA: Hi, my name is Maya from Pemberton, BC. My question is, how were mountains formed?
DIEGO: My question is, how do mountains formed? I thought about this question when I was reading a book about mountains.
MOLLY BLOOM: Thanks to Diego and Maya for sending us those questions. We'll hear more of your mountain questions later in the show. So let's start with how mountains are formed.
SANDEN TOTTEN: Oh, I got this one. It all starts with itty-bitty molehills. Those are baby mountains. As long as they eat all their vegetables, they grow big and strong. Before you know it, bam, mountain formed. Next question.
MOLLY BLOOM: Sanden, are you sure about that?
SANDEN TOTTEN: Yeah, no. I just said the first thing that popped into my head.
MARC SANCHEZ: We might need back up.
MOLLY BLOOM: You know what this calls for?
MARC SANCHEZ: Time to speed dial a scientist.
[THEME MUSIC PLAYING]
MOLLY BLOOM: Let's call up our friend Dr. Dalia Kirschbaum. She's a research scientist and chief of the hydrological sciences lab at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
[DIALING]
Hello, Dahlia, are you there?
DALIA KIRSCHBAUM: Hi.
MOLLY BLOOM: Dahlia, it's Molly, Marc, Sanden, and Baxter here. We are so glad we got a hold of you.
DALIA KIRSCHBAUM: Sure.
BAXTER: Dalia, how do mountains form in the first place?
DALIA KIRSCHBAUM: Well, understanding how mountains form is such a great question. One of the things we have to realize is that we're standing on the surface. We're here where there's grass and there's soil and rocks, that's pebbles. But what's happening underneath the surface is really exciting.
Directly underneath our crust, we have this really big rocky layer of Earth. That's made up of 50 different tectonic plates, which is these different plates that are moving around usually really, really slowly.
BAXTER: The Earth's crust is like a bunch of plates?
DALIA KIRSCHBAUM: Think of them more like puzzle pieces that fit together to cover the planet. But instead of these puzzle pieces fitting on your coffee table, there are thousands of miles wide and some are the size of entire continents.
BAXTER: Whoa, that's an epic puzzle.
MOLLY BLOOM: Yeah, and these plates are always sliding and moving and bumping into each other, but very slowly. Still, with plates that big, all that action makes for some dramatic changes on the surface of the planet.
DALIA KIRSCHBAUM: When these plates move, it can cause different mountain types to form. And there's lots of different types of mountains, but in addition to mountains we can also get valleys. And that's what forms what we call the topography or the different changes in elevation all around our Earth.
BAXTER: So how exactly do these plates make mountains?
DALIA KIRSCHBAUM: One of the ways you can think of this is if you fold up a dish towel and you put you flatten it out on a table, and then you put your hands and start to move them together really slowly, you can start to see the folds which go up and down of the towel.
SANDEN TOTTEN: Ooh, I want to try. Let's see. So if I put my hands on either end of this towel here and I push my hands together, look, a little tiny peek formed at the center.
BAXTER: Just like a mountain.
SANDEN TOTTEN: I'm calling this the dish rag range.
DALIA KIRSCHBAUM: Plates can move next to each other or go underneath each other that can form different types of mountains. And then we also have volcanoes that can add to the different mountain building processes.
BAXTER: Volcanoes? How does that work?
DALIA KIRSCHBAUM: So we talked about the crust or we talked about this thick layer with plates in it. But underneath that is actually a molten layer, which has magma in it. When there's a hot spot, when things get hot, that can actually poke through the crust, and that can cause volcanoes. That can build up the magma, builds up and builds up and creates different forms of volcanoes that are also types of mountains.
SANDEN TOTTEN: And you said they move really slowly, but how slow are we talking about here? Slower than a turtle?
MARC SANCHEZ: Slower than Sanden before his morning coffee?
BAXTER: Slower than Bob alphabetizing brains on headquarters?
DALIA KIRSCHBAUM: That's right. Well, this is a very, very slow process. But to build a mountain range as tall as Mount Everest, which is the tallest mountain in the world, it takes a really long time. Some of the oldest mountains that we have on the planet are from 3.5 billion years ago, and those are in Africa as well as in Australia. But actually, if anyone's ever been to this Black Hills in South Dakota and Wyoming, those formed 1.8 billion years ago. That's a really, really long time ago.
MARC SANCHEZ: These mountains are ba ba ba billions of years old?
SANDEN TOTTEN: That's way before the dinosaurs first roamed Earth.
MOLLY BLOOM: Yeah, fun fact, those tectonic plates move so slow, they're actually moving at the same rate that our fingernails grow which is a couple of millimeters every few months. That's why it takes millions and billions of years for them to form the majestic mountains we know today.
SANDEN TOTTEN: Wow.
BAXTER: Wow.
DALIA KIRSCHBAUM: Now, in comparison, some of the newest mountain ranges are actually in Asia in what's called the Himalayas. And they were formed a very short 40 million years ago. They're home to the highest peaks on Earth, and specifically Mount Everest is 5 and 1/2 miles above sea level, which is where the ocean meets.
BAXTER: When it comes to mountains, 40 million years ago is new?
MOLLY BLOOM: Kind of wild, right? But yeah, it's true. Millions of years isn't very long when it comes to geology.
BAXTER: Most mountains were formed over millions, even billions of years ago. Are any of them still growing today?
DALIA KIRSCHBAUM: We know that some mountains are getting taller and some mountains are getting shorter, and they're doing this through different processes. Let's first talk about the mountains that are getting taller. As these plates move together, if you're moving your hands, if one of them goes under the other plate which is called subduction, the plate that's on top gets pushed up.
SANDEN TOTTEN: I see. If I start with my hands flat, fingertip to fingertip, and I slowly start to push my left hand over my right one, my left fingertips get higher and higher as my right hand pushes underneath. Cool.
DALIA KIRSCHBAUM: And that's what's happening in Mount Everest right now in that region. The plate from India is actually going under the plate from Asia, and that causes the mountains to get higher.
MARC SANCHEZ: Mount Everest? More like Mount Never-est. Because it's still growing. You guys get it, right?
DALIA KIRSCHBAUM: Now, in other areas and in all mountain ranges, mountains can get shorter. And this is caused by erosion and by weather and climate. With rain, lots of rain and earthquakes, it can shake up the rocks and cause them to go downhill.
MOLLY BLOOM: It's like when you're making a sandcastle at the beach. A gust of wind could blow away the top of your tower or maybe it starts raining and your castle walls start to fall. That's like erosion wearing down a mountain over time, right?
DALIA KIRSCHBAUM: That's right.
MOLLY BLOOM: Oh, we must be getting close to the top because service is getting spotty, Dalia.
BAXTER: Thanks, Dalia, for speaking with us.
[THEME MUSIC PLAYING]
MOLLY BLOOM: All right, Baxter. Marc has equipped this Explorer with a fun game to keep us occupied while we drive. Marc, press the button because it's time for the--
BAXTER: Mystery Sound.
MOLLY BLOOM: Here it is.
[SQUISHING]
All right, Baxter. What is your guess?
BAXTER: It sounds like someone sticking their foot in something dewy, then taking it out. Then putting it back and then taking it out again.
MOLLY BLOOM: Very, very good guess.
BAXTER: But then also, it also sounds like someone moving rocks at the same time.
MOLLY BLOOM: Gooey. Sticky. Feet. Rocks. Something. All right, well, we're going to hear it again and give you another chance to guess right after the credits.
[MUSIC PLAYING]
We're working on an episode all about worms and we want to hear from you. If you could name a pet worm, what name would you give them? Baxter, what would you name worm?
BAXTER: Jerry.
MOLLY BLOOM: Delightful. Record your answer and send it to us at brainson.org/contact.
BAXTER: While you're there, you can also send us mystery sounds, drawings, ideas, and questions.
MARC SANCHEZ: Just like this one.
EVA: My name is Eva from Michigan. My question is, why do pine trees not lose their needles in the winter like how other trees lose their lives?
SANDEN TOTTEN: You can find an answer to that on our new Moment of Um podcast. Find it and subscribe wherever you listen to Brains On.
MARC SANCHEZ: And it would mean a lot to us, like a lot a lot. If you ordered our new books, we have a book called Road Trip Earth documenting our epic road trip in the Explorer.
BAXTER: It's full of facts, comics, mystery photos and more.
SANDEN TOTTEN: And we also have a picture book too. It's called Earth Friend Forever.
MOLLY BLOOM: You can check out all three Brains On books at brainson.org/books. Thank you so much.
BAXTER: And keep listening.
You're listening to Brains On from APM Studios. I'm Baxter.
MOLLY BLOOM: And I'm Molly.
SANDEN TOTTEN: And I'm Sanden.
MARC SANCHEZ: And I'm Marc. And we're rolling, rolling, rolling up the mountain.
BAXTER: To find out why it's so cold up there.
MOLLY BLOOM: Let's roll down the window and see what the temperature is like now.
[WINDOW OPENS]
MARC SANCHEZ: Refreshing mountain air.
MOLLY BLOOM: Did you know the air is thinner up high? Yeah, that means there's less oxygen in every breath. So that might be why you keep taking those deep refreshing inhales, Marc.
MARC SANCHEZ: Good gravy, Molly. Close the window. It's freezing.
MOLLY BLOOM: OK. OK.
MARC SANCHEZ: The hills are alive with the sound of--
SANDEN TOTTEN: Buzzing.
MARC SANCHEZ: A bumblebee flew in.
BAXTER: A bumblebee up here?
BEE: That's Miss Bee if you please. Yes, bumblebees can fly at very high altitudes. As the air gets thinner, we just beat our wings at a wider angle to stay afloat.
MOLLY BLOOM: But don't you get colds?
BEE: Well, yes, sometimes. I could fly over the top of Mount Everest. But I prefer to fly at lower altitudes because it's just too darn cold way up there.
MARC SANCHEZ: It is. It's too darn cold. Too darn cold.
BEE: Oh, there's my field of Columbine flowers. Let me off here, please.
MOLLY BLOOM: Pulling over.
BEE: I'll see you later.
MOLLY BLOOM: Bye, Miss Bee.
MARC SANCHEZ: Great to meet you, but it ain't no love. Bumblebee bye, bye, bye, bye.
[CHIRP]
SANDEN TOTTEN: Marc, enough with the singing.
[CHIRP]
MARC SANCHEZ: That's not me.
[CHIRP]
SANDEN TOTTEN: Ha ha. Very funny, Marc. But look, this is a long trip and I'm going to need some peace and--
[CHIRP]
MOLLY BLOOM: No, Marc's right. The sound's coming from--
PIKA: Me.
MOLLY BLOOM: Look over there on that little rocky outcropping.
BAXTER: Is that a mouse?
PIKA: No, I'm a pika. I might look like a mouse but I'm actually more closely related to rabbits. People think I'm very cute.
SANDEN TOTTEN: You are, but you're also very noisy, like Marc.
PIKA: I'll take that as a compliment.
MOLLY BLOOM: How do you survive all the way up here?
PIKA: Our bodies are specially designed to survive on thin air with low oxygen levels. Plus the heat is our enemy. If it's over 78 degrees Fahrenheit, we can die from overheating.
SANDEN TOTTEN: Oh, no.
PIKA: Oh, yes. So the crisp mountain air is part of how we survive. Now, if you'll excuse me, I need to go munch on some more wildflowers.
SANDEN TOTTEN: OK, bye.
MOLLY BLOOM: Bye. Close the door you guys.
MARC SANCHEZ: On the road again. Say goodbye to my little pika friend.
SANDEN TOTTEN: Marc?
MARC SANCHEZ: Sorry. I can't help it. Road trips make me singing. Laugh at the highway. I want to run it all day long. Wait, whoa. Watch out up ahead. There is something in the road.
YAK: Frankie. Frankie.
[WINDOW OPENS]
SANDEN TOTTEN: Wow, those are some furry cows.
MOLLY BLOOM: Oh, those are yaks.
NAKS: And naks. Female yaks are called naks.
MOLLY BLOOM: Oh, my apologies. Your fur looks very warm.
NAKS: It is. It keeps us warm at up to -40 degrees Fahrenheit. We also have huge lungs so our body can capture lots of oxygen from the thin air. Then our huge heart helps pump that oxygen in our blood around our body, which keeps us warm.
MARC SANCHEZ: My, what big horns you have?
NAKS: Better to smash the snow with, my dear. We eat the greens underneath and lick moss and lichen off of rocks with our scratchy tongues.
MARC SANCHEZ: Ooh, wow.
BAXTER: Hey, look. There's mountain goats too. See, those white animals up there walking on the sheer rock wall.
MARC SANCHEZ: Wow. How do they do it?
MOLLY BLOOM: Ooh, their hooves are cloven so they spread wide for amazing balance. Young goats can even start scrambling around the day after they're born.
MARC SANCHEZ: Oh, cool. Let's go say Hello. I want to meet them.
MOLLY BLOOM: Maybe not. Female mountain goats can be vicious if they think you're threatening they're young, and that one has a kid.
MARC SANCHEZ: That doesn't sound like a kid to me. Get some more like this. I have so much energy. I'm a little kid. I didn't even have any coffee. This is just what it's like to be me. Whoa.
MOLLY BLOOM: Baby mountain goats are called kids.
MARC SANCHEZ: Oh.
SANDEN TOTTEN: I thought high up on a mountaintop you, wouldn't find any wild animals. But given all the wildlife we've seen, I was clearly wrong.
MOLLY BLOOM: Totally. Now, let's go. We are almost at the top.
SANDEN TOTTEN: So come on, let's drive, drive, drive.
MARC SANCHEZ: Look, who's singing now?
MOLLY BLOOM: Woo. Yeah.
[WIND BLOWING]
We finally made it. Oh, what a view up here?
SANDEN TOTTEN: Yeah, I think I can see headquarters. And wait, is that Gungador using my eyebrow brush again? Hey, you lovable monster. Get your own brow brush.
BAXTER: Sure it's cold though.
MOLLY BLOOM: Yeah, good thing I packed a pack of purple and pink power parkas. Perfect for pairing off pretty peaks.
MR BART: Ice cream. Ice cream. Live the dream with ice cream.
MARC SANCHEZ: Ooh, ice cream.
SANDEN TOTTEN: Ice cream all the way up here?
MR BART: Yes, sir. Indeedy Doody. I've got flavors from chocolate to fruity. Want a snack but forgot to pack? I've got you covered. I've got your back. Get ready for a flavor attack.
MARC SANCHEZ: Who is this dude?
MR BART: It's me. Hello, I'm Mr Bart. The rhyming dancing ice cream cart guy.
BAXTER: Mr. Bart, don't you think it's a little cold for ice cream?
MR BART: I thought up here so close to the sun, it's sure to be hotter than a hot cross bun. But Lo and behold, on a mountaintop, it's frostier than my frostiest pop.
BAXTER: Yeah, it's hot. I mean, hot air rises and we're closer to the sun. So why is it that it's so cold? I've always wondered that.
MOLLY BLOOM: Our listeners wondered that too. Actually, I think I brought their questions with me. Yeah, here, in this jar. Let me unscrew the cap.
BEN: My name is Ben from Los Angeles, California.
NORA: My name is Nora from Omaha, Nebraska.
OLIVER: My name is Oliver from Phoenix, Maryland.
MAGENTA: My name is Magenta. I'm from Brisbane in Australia.
NORA: If hot air rises.
MAGENTA: Why does it get colder when you go higher?
BEN: A few years back, we went to the Rocky Mountains and it was super cold up there but we forgot warm clothes.
OLIVER: I went on a camping trip to Arizona. We went to a higher elevation and it was really cold while the desert was hot.
MAGENTA: When you climb a mountain, shouldn't it be warm up because you're closer to the sun?
BAXTER: Whoa. Great questions.
SANDEN TOTTEN: Yeah, I also have some questions. How did you get those into a jar?
MARC SANCHEZ: Yeah, I can help explain this one. There are actually a bunch of reasons why it's colder on top of mountains. I was just talking to my pal Deanna Hence about this.
MOLLY BLOOM: Oh, Deanna Hence? Assistant professor of Atmospheric Science at the University of Illinois, Urbana-Champaign?
MARC SANCHEZ: Yeah, her.
MOLLY BLOOM: Cool. What did she say?
MARC SANCHEZ: Well, she told me a lot of it has to do with how hot air works in general. You see hot air comes from the sun warming up the ground, and that warm ground then passes that energy to the air around it, which sounds a little hard to picture, but sometimes you can actually see it happening. How did she explain it? Oh, wait, I have her explanation here in this ziploc bag.
DEANNA HENCE: So you can see this probably most dramatically when you're out in a desert and you say, looking at a road, and you're seeing it be all shiny. Well, that shininess is a mirage. And the reason why that mirage is actually happening is because the air that's immediately above the ground is being heated by the ground and that's actually changing how light bends through the air.
MARC SANCHEZ: So if you see a mirage on some concrete on a hot day, you're just seeing the ground heating up some low lying air. Cool, right? I mean, hot, right?
BAXTER: Very. I didn't know that about mirages.
SANDEN TOTTEN: And I did not know you could put a voice into a ziploc bag. Can you tell me how--
MARC SANCHEZ: Yeah, so that hot air it rises and it expands. Which means it goes up and wants to spread out. But here's what happens as it does that. Is that bubble of hot air floats up, it becomes surrounded by cooler and cooler air, and it starts to lose its energy, its heat. Oh, think of it like this. Picture of bounce house full of rowdy kids.
The kids are like the excited air molecules full of energy, which makes them shoot around really fast. The pocket of warm air is like the bounce house. Now, as these kids bounce around, boing, boing, boing, they actually push against the bounce house so hard they stretch it out making it bigger and bigger.
BAXTER: Just like the warm air expands as it rises.
MARC SANCHEZ: Exactly. But stretching out that bounce house, as you can imagine, that's a lot of hard work, and it takes a lot of energy. So the longer these kids do it, the more tired they become until eventually they're pooped.
What that means for hot air is as it expands and rises, it uses up all its energy a.k.a. its heat, and eventually it cools down. That happens way before it reaches a mountaintop. So even though hot air rises, it doesn't have enough energy to go from the ground all the way to the tippy top of a tall mountain. So that's part of why it's cold up here.
MR BART: But riddle me this, my learned fellow. Take a look around. We are up high. That is true. But we are also on the ground. Wouldn't the sun warm this too creating hot air on this peak? If so, then why have I been so cold selling ice cream here all week?
MARC SANCHEZ: Great follow up, Mr. Bart. You see the sun is warming the ground here, too. But the answer you seek has to do with the peak.
MR BART: That rhyme was nice. My home slice.
MARC SANCHEZ: I know, right? Here, Deanna explain this to me too, and I think I brought an explanation in this pocket. Oh, shoot. No, no. That's my tap dancing elephant sound, better put that back. Whoa, not that pocket. Here we go. She said when you're on a peak, you have ground under you but not as much around you.
DEANNA HENCE: Because you're on a slope and you're basically exposed to air that's not touching the ground. If you think about if you're like standing in a field in a very flat space. If you're getting a breeze across your face, all that air has had time to just travel over just miles and miles and miles of warm land.
As it's doing that, it's picking up heat from the ground as it's traveling over the ground. If you're at the top of a mountain, yeah, maybe the little pocket that's right around you maybe getting heated by the ground that you're standing on. But a lot of the air that's coming from that breeze, it's all coming from stuff that's not touching the ground.
MARC SANCHEZ: And that other air the stuff around the peak it's cold. And it makes the breeze and the air up high pretty cold, too. Wow
MOLLY BLOOM: That. Answer deserves a standing ovation. I have one here in my wallet.
[APPLAUSE]
SANDEN TOTTEN: OK. Am I the only one who isn't carrying sounds with them at all times?
MARC SANCHEZ: As for the sun, yeah we're closer. But given how far the sun is from the planet, we're really not close enough to make a difference heat wise. These are just some of the reasons it's cold on top of a mountain and why you Mr. Bart probably should have sold hot chocolate instead of frozen fudgicicles.
MR BART: Wow. I feel so much smarter having learned about air and atmospheric science. Now, excuse me while I move my cart and something rhymes with science. Bye.
MOLLY BLOOM: Wait, Mr. Bart, will you join us for our group photo?
MR BART: I thought you'd never ask. Being in photos is my favorite task.
SANDEN TOTTEN: Ooh, let's get the mountain animals in on this too.
MARC SANCHEZ: OK, huddle in everybody. Hey, yak and nak, you're blocking Baxter, so scooch over just-- OK, perfect right there. All right. Say cheese.
ALL: Cheese
MR BART: If you please.
MOLLY BLOOM: And stick around for the answer to the mystery sound in just a moment.
BAXTER: Mountains forming tectonic plates crash into each other or overlap.
MOLLY BLOOM: This takes millions and millions of years and some mountains are still growing today.
BAXTER: Volcanoes are also a type of mountain.
MOLLY BLOOM: Mountains are full of wonder animals that have special features that help them survive a high.
BAXTER: Even though the hot air rises, the air loses energy as it floats up so mountain tops are usually very cold.
MOLLY BLOOM: That's it for this episode of Brains On.
BAXTER: This episode was produced by Molly Bloom, Rosie DuPont, Ruby Guthrie, Marc Sanchez, Sanden Totten and Menaka Wilhelm.
MOLLY BLOOM: Our fellow is Anna Goldfield and our executive producer is Beth Pearlman. We had engineering help from Johnny Vince Evans, Noah Cole, and Peter Starkey. The executives in charge of APM Studios are Lilly Kim, Alex Shaffer, and Joanne Griffith. Special thanks to Rick and Kari Thackery and Anna Weigel.
BAXTER: Brains On is a nonprofit public radio program.
MOLLY BLOOM: There are lots of ways you can support the show. You can donate by our books or tell your friends about us.
BAXTER: Head to brainson.org to find the links to donate and buy the books.
MOLLY BLOOM: And remember, you can find an answer to the Moment of Um question, do mice really like cheese? on the Moment of Um podcast. Before we go Baxter, are you ready to hear that mystery sound one more time?
BAXTER: Yes.
MOLLY BLOOM: Here it is.
[SQUISHING]
Any new thoughts?
BAXTER: I think my first guess was right, like the sticking the foot and something sticky.
MOLLY BLOOM: Do you have any thoughts about what that sticky substance might be?
BAXTER: Maybe mud, but I'm not sure.
MOLLY BLOOM: It's true. Our listeners like to stump us with their mystery sounds. So it could be jello for all we know. Are you ready for the answer?
BAXTER: Yes.
MOLLY BLOOM: Here it is.
MAISIE: Hi, my name is Maisie and I'm from Petaluma, California. And that was the sound of me stepping in mud. I made it squishier by mixing more mud together with it. It's very sticky.
MOLLY BLOOM: Baxter, nice work.
BAXTER: Thanks.
MOLLY BLOOM: So have you walked through mud yourself?
BAXTER: Yes, there's been a lot of mud with the snow melting, then more snow falling than all that snow melting, and then it raining, and then more snow than that snow melting.
MOLLY BLOOM: You do a lot of experience with mud.
BAXTER: Yeah.
[THEME MUSIC PLAYING]
MOLLY BLOOM: I am very excited to read this list of names. It's time for the Brains Honor Roll. These are the incredible listeners who send us their drawings, mystery sounds, questions, and high fives.
[LISTING HONOR ROLL]
[THEME MUSIC PLAYING]
We'll be back soon with more answers to your questions.
BAXTER: Thanks for listening.
DUMINKA: Brains On is supported in part by a grant from the National Science Foundation.
MOLLY BLOOM: OK, this star trip has been amazing. I can't believe we've traveled from the inner core of the Earth all the way to the moon. We've got so much great material for our new book Road Trip Earth.
SANDEN TOTTEN: It's been epic. People are going to love this book. And I can't wait to show everybody my road trip photos.
MOLLY BLOOM: Our road trip photos?
SANDEN TOTTEN: Well, they're mostly of me because let's face it, I'm everyone's favorite.
MOLLY BLOOM: You mean you are your favorites.
SANDEN TOTTEN: Exactly. But there's got to be one of you in here somewhere. Oh look, here. You can see the back of your head in this one.
MOLLY BLOOM: Well, that's something. Marc, how about we pull over all terrain, all planet vehicle to stretch our legs and replenish our snacks? We may be in the homestretch, but we still got a little ways to go.
MARC SANCHEZ: On it. Pulling over the Explorer a.k.a. the extremely practical land and ocean rover exploring remote realms. Look, I know, the whole point of an acronym is so I don't have to say the whole name every time. But it's so fun. Extremely practical land an ocean rover exploring remote realms. Extremely practical--
MOLLY BLOOM: Oh, Menaka is calling. Hi, Menaka. We miss you.
SANDEN TOTTEN: Menaka, did you get the last selfie I texted you?
MENAKA WILHELM: I did. As well as the other 37 selfies since we last talked.
SANDEN TOTTEN: Which is your favorite. It's OK to say all of them.
MARC SANCHEZ: Menaka, I can't wait to see you.
MENAKA WILHELM: I know. I'm so excited you guys are on your way back out. But I'm not just calling to say Hi. We have a bit of an issue here at Brains On headquarters.
MARC SANCHEZ: Oh, no. What's up?
MENAKA WILHELM: Well, Baxter just got here to record an episode with me.
BAXTER: Hi, guys.
ALL: Hey, Baxter.
MENAKA WILHELM: But when we got into the studio Bob was in there, and he had pretty much dismantled and alphabetized all the gear. It's going to take me at least a few hours to get it back into working order. I was wondering if I could have elevator drop Baxter off at the Explorer, and then you guys can record there.
MARC SANCHEZ: Oh, sure. I built a suite mobile studio in here too. Sending elevator our coordinates now.
MENAKA WILHELM: OK, awesome. Thank you so much. Oh, got to run. Bob, please stop alphabetizing. Maybe take a soup break.
MARC SANCHEZ: All right. Baxter should be here in 3, 2.
ELEVATOR: Here we are. The Brains On extremely practical land and ocean rover exploring remote realms.
MOLLY BLOOM: Thanks, elevator.
ELEVATOR: Happy to have a break from writing my memoir. The uplifting life of the world's smartest elevator. OK, bye.
MOLLY BLOOM: Hey, Baxter. So this was an episode about mountains, right?
BAXTER: Yeah.
MOLLY BLOOM: Well, this is perfect because there's a mountain right over there, and I think the top of it would be the ideal spot for a group photo to commemorate our road trip. Let's record the episode on our way up. That sound good?
BAXTER: Let's do it.
MARC SANCHEZ: All right, everyone. Buckle up. We have a mountain to climb.
[THEME MUSIC PLAYING]
MOLLY BLOOM: You are listening to Brains On from APM Studios. I'm Molly Bloom, and today we're broadcasting from the Brains On Explorer with my co-host Baxter from Camden, Maine. Hi, Baxter.
BAXTER: Hi.
MOLLY BLOOM: Thank you for joining us.
BAXTER: I'm always down for an adventure or up because we're going up a mountain.
MOLLY BLOOM: That's exactly what we like to hear. You wrote to us with a question about mountains.
BAXTER: Yeah, I want to know, if heat rises, then why is it so cold at the top of mountains?
MOLLY BLOOM: When were you inspired to ask that question? What made you think of it?
BAXTER: I think it was like one or two years ago when we were hiking up. I forget what mountain. I think it was someplace close to Camden, but I'm not sure. I asked that at the top of the mountain.
MOLLY BLOOM: It's a very good question. Where is the closest mountain to you where you live?
BAXTER: Oh, I could walk to it in probably 10 minutes.
MOLLY BLOOM: Oh, so you can see it from your house?
BAXTER: Yeah.
MOLLY BLOOM: When did you start hiking up mountains?
BAXTER: I've been hiking for quite a while. Even before I could hike, my parents were always hiking mountains while I was in a little backpack basically.
MOLLY BLOOM: So you've been like hiking mountains since before you could even hike yourself, you've been all over. That's awesome.
BAXTER: Yeah.
MOLLY BLOOM: So what is your favorite thing about hiking mountains?
BAXTER: It's just peaceful and it's repetitive and leaves you lots of times to just think about stuff.
MOLLY BLOOM: The mountain by your house that's so close, have you hiked up that mountain?
BAXTER: Yes, it's not that tall. It's like 1,000 feet or something straight up.
MOLLY BLOOM: That sounds tall to me.
BAXTER: But the tallest mountain that I think I've hiked is like 6,000 something feet.
MOLLY BLOOM: Wow. Yeah, mountains are amazing and I'm so glad someone with so much first hand mountain experience is here to help us answer the mountains of questions from our listeners all about these picture perfect peaks.
DIEGO: Hi, my name is Diego and I'm from San Francisco, California.
MAYA: Hi, my name is Maya from Pemberton, BC. My question is, how were mountains formed?
DIEGO: My question is, how do mountains formed? I thought about this question when I was reading a book about mountains.
MOLLY BLOOM: Thanks to Diego and Maya for sending us those questions. We'll hear more of your mountain questions later in the show. So let's start with how mountains are formed.
SANDEN TOTTEN: Oh, I got this one. It all starts with itty-bitty molehills. Those are baby mountains. As long as they eat all their vegetables, they grow big and strong. Before you know it, bam, mountain formed. Next question.
MOLLY BLOOM: Sanden, are you sure about that?
SANDEN TOTTEN: Yeah, no. I just said the first thing that popped into my head.
MARC SANCHEZ: We might need back up.
MOLLY BLOOM: You know what this calls for?
MARC SANCHEZ: Time to speed dial a scientist.
[THEME MUSIC PLAYING]
MOLLY BLOOM: Let's call up our friend Dr. Dalia Kirschbaum. She's a research scientist and chief of the hydrological sciences lab at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
[DIALING]
Hello, Dahlia, are you there?
DALIA KIRSCHBAUM: Hi.
MOLLY BLOOM: Dahlia, it's Molly, Marc, Sanden, and Baxter here. We are so glad we got a hold of you.
DALIA KIRSCHBAUM: Sure.
BAXTER: Dalia, how do mountains form in the first place?
DALIA KIRSCHBAUM: Well, understanding how mountains form is such a great question. One of the things we have to realize is that we're standing on the surface. We're here where there's grass and there's soil and rocks, that's pebbles. But what's happening underneath the surface is really exciting.
Directly underneath our crust, we have this really big rocky layer of Earth. That's made up of 50 different tectonic plates, which is these different plates that are moving around usually really, really slowly.
BAXTER: The Earth's crust is like a bunch of plates?
DALIA KIRSCHBAUM: Think of them more like puzzle pieces that fit together to cover the planet. But instead of these puzzle pieces fitting on your coffee table, there are thousands of miles wide and some are the size of entire continents.
BAXTER: Whoa, that's an epic puzzle.
MOLLY BLOOM: Yeah, and these plates are always sliding and moving and bumping into each other, but very slowly. Still, with plates that big, all that action makes for some dramatic changes on the surface of the planet.
DALIA KIRSCHBAUM: When these plates move, it can cause different mountain types to form. And there's lots of different types of mountains, but in addition to mountains we can also get valleys. And that's what forms what we call the topography or the different changes in elevation all around our Earth.
BAXTER: So how exactly do these plates make mountains?
DALIA KIRSCHBAUM: One of the ways you can think of this is if you fold up a dish towel and you put you flatten it out on a table, and then you put your hands and start to move them together really slowly, you can start to see the folds which go up and down of the towel.
SANDEN TOTTEN: Ooh, I want to try. Let's see. So if I put my hands on either end of this towel here and I push my hands together, look, a little tiny peek formed at the center.
BAXTER: Just like a mountain.
SANDEN TOTTEN: I'm calling this the dish rag range.
DALIA KIRSCHBAUM: Plates can move next to each other or go underneath each other that can form different types of mountains. And then we also have volcanoes that can add to the different mountain building processes.
BAXTER: Volcanoes? How does that work?
DALIA KIRSCHBAUM: So we talked about the crust or we talked about this thick layer with plates in it. But underneath that is actually a molten layer, which has magma in it. When there's a hot spot, when things get hot, that can actually poke through the crust, and that can cause volcanoes. That can build up the magma, builds up and builds up and creates different forms of volcanoes that are also types of mountains.
SANDEN TOTTEN: And you said they move really slowly, but how slow are we talking about here? Slower than a turtle?
MARC SANCHEZ: Slower than Sanden before his morning coffee?
BAXTER: Slower than Bob alphabetizing brains on headquarters?
DALIA KIRSCHBAUM: That's right. Well, this is a very, very slow process. But to build a mountain range as tall as Mount Everest, which is the tallest mountain in the world, it takes a really long time. Some of the oldest mountains that we have on the planet are from 3.5 billion years ago, and those are in Africa as well as in Australia. But actually, if anyone's ever been to this Black Hills in South Dakota and Wyoming, those formed 1.8 billion years ago. That's a really, really long time ago.
MARC SANCHEZ: These mountains are ba ba ba billions of years old?
SANDEN TOTTEN: That's way before the dinosaurs first roamed Earth.
MOLLY BLOOM: Yeah, fun fact, those tectonic plates move so slow, they're actually moving at the same rate that our fingernails grow which is a couple of millimeters every few months. That's why it takes millions and billions of years for them to form the majestic mountains we know today.
SANDEN TOTTEN: Wow.
BAXTER: Wow.
DALIA KIRSCHBAUM: Now, in comparison, some of the newest mountain ranges are actually in Asia in what's called the Himalayas. And they were formed a very short 40 million years ago. They're home to the highest peaks on Earth, and specifically Mount Everest is 5 and 1/2 miles above sea level, which is where the ocean meets.
BAXTER: When it comes to mountains, 40 million years ago is new?
MOLLY BLOOM: Kind of wild, right? But yeah, it's true. Millions of years isn't very long when it comes to geology.
BAXTER: Most mountains were formed over millions, even billions of years ago. Are any of them still growing today?
DALIA KIRSCHBAUM: We know that some mountains are getting taller and some mountains are getting shorter, and they're doing this through different processes. Let's first talk about the mountains that are getting taller. As these plates move together, if you're moving your hands, if one of them goes under the other plate which is called subduction, the plate that's on top gets pushed up.
SANDEN TOTTEN: I see. If I start with my hands flat, fingertip to fingertip, and I slowly start to push my left hand over my right one, my left fingertips get higher and higher as my right hand pushes underneath. Cool.
DALIA KIRSCHBAUM: And that's what's happening in Mount Everest right now in that region. The plate from India is actually going under the plate from Asia, and that causes the mountains to get higher.
MARC SANCHEZ: Mount Everest? More like Mount Never-est. Because it's still growing. You guys get it, right?
DALIA KIRSCHBAUM: Now, in other areas and in all mountain ranges, mountains can get shorter. And this is caused by erosion and by weather and climate. With rain, lots of rain and earthquakes, it can shake up the rocks and cause them to go downhill.
MOLLY BLOOM: It's like when you're making a sandcastle at the beach. A gust of wind could blow away the top of your tower or maybe it starts raining and your castle walls start to fall. That's like erosion wearing down a mountain over time, right?
DALIA KIRSCHBAUM: That's right.
MOLLY BLOOM: Oh, we must be getting close to the top because service is getting spotty, Dalia.
BAXTER: Thanks, Dalia, for speaking with us.
[THEME MUSIC PLAYING]
MOLLY BLOOM: All right, Baxter. Marc has equipped this Explorer with a fun game to keep us occupied while we drive. Marc, press the button because it's time for the--
BAXTER: Mystery Sound.
MOLLY BLOOM: Here it is.
[SQUISHING]
All right, Baxter. What is your guess?
BAXTER: It sounds like someone sticking their foot in something dewy, then taking it out. Then putting it back and then taking it out again.
MOLLY BLOOM: Very, very good guess.
BAXTER: But then also, it also sounds like someone moving rocks at the same time.
MOLLY BLOOM: Gooey. Sticky. Feet. Rocks. Something. All right, well, we're going to hear it again and give you another chance to guess right after the credits.
[MUSIC PLAYING]
We're working on an episode all about worms and we want to hear from you. If you could name a pet worm, what name would you give them? Baxter, what would you name worm?
BAXTER: Jerry.
MOLLY BLOOM: Delightful. Record your answer and send it to us at brainson.org/contact.
BAXTER: While you're there, you can also send us mystery sounds, drawings, ideas, and questions.
MARC SANCHEZ: Just like this one.
EVA: My name is Eva from Michigan. My question is, why do pine trees not lose their needles in the winter like how other trees lose their lives?
SANDEN TOTTEN: You can find an answer to that on our new Moment of Um podcast. Find it and subscribe wherever you listen to Brains On.
MARC SANCHEZ: And it would mean a lot to us, like a lot a lot. If you ordered our new books, we have a book called Road Trip Earth documenting our epic road trip in the Explorer.
BAXTER: It's full of facts, comics, mystery photos and more.
SANDEN TOTTEN: And we also have a picture book too. It's called Earth Friend Forever.
MOLLY BLOOM: You can check out all three Brains On books at brainson.org/books. Thank you so much.
BAXTER: And keep listening.
You're listening to Brains On from APM Studios. I'm Baxter.
MOLLY BLOOM: And I'm Molly.
SANDEN TOTTEN: And I'm Sanden.
MARC SANCHEZ: And I'm Marc. And we're rolling, rolling, rolling up the mountain.
BAXTER: To find out why it's so cold up there.
MOLLY BLOOM: Let's roll down the window and see what the temperature is like now.
[WINDOW OPENS]
MARC SANCHEZ: Refreshing mountain air.
MOLLY BLOOM: Did you know the air is thinner up high? Yeah, that means there's less oxygen in every breath. So that might be why you keep taking those deep refreshing inhales, Marc.
MARC SANCHEZ: Good gravy, Molly. Close the window. It's freezing.
MOLLY BLOOM: OK. OK.
MARC SANCHEZ: The hills are alive with the sound of--
SANDEN TOTTEN: Buzzing.
MARC SANCHEZ: A bumblebee flew in.
BAXTER: A bumblebee up here?
BEE: That's Miss Bee if you please. Yes, bumblebees can fly at very high altitudes. As the air gets thinner, we just beat our wings at a wider angle to stay afloat.
MOLLY BLOOM: But don't you get colds?
BEE: Well, yes, sometimes. I could fly over the top of Mount Everest. But I prefer to fly at lower altitudes because it's just too darn cold way up there.
MARC SANCHEZ: It is. It's too darn cold. Too darn cold.
BEE: Oh, there's my field of Columbine flowers. Let me off here, please.
MOLLY BLOOM: Pulling over.
BEE: I'll see you later.
MOLLY BLOOM: Bye, Miss Bee.
MARC SANCHEZ: Great to meet you, but it ain't no love. Bumblebee bye, bye, bye, bye.
[CHIRP]
SANDEN TOTTEN: Marc, enough with the singing.
[CHIRP]
MARC SANCHEZ: That's not me.
[CHIRP]
SANDEN TOTTEN: Ha ha. Very funny, Marc. But look, this is a long trip and I'm going to need some peace and--
[CHIRP]
MOLLY BLOOM: No, Marc's right. The sound's coming from--
PIKA: Me.
MOLLY BLOOM: Look over there on that little rocky outcropping.
BAXTER: Is that a mouse?
PIKA: No, I'm a pika. I might look like a mouse but I'm actually more closely related to rabbits. People think I'm very cute.
SANDEN TOTTEN: You are, but you're also very noisy, like Marc.
PIKA: I'll take that as a compliment.
MOLLY BLOOM: How do you survive all the way up here?
PIKA: Our bodies are specially designed to survive on thin air with low oxygen levels. Plus the heat is our enemy. If it's over 78 degrees Fahrenheit, we can die from overheating.
SANDEN TOTTEN: Oh, no.
PIKA: Oh, yes. So the crisp mountain air is part of how we survive. Now, if you'll excuse me, I need to go munch on some more wildflowers.
SANDEN TOTTEN: OK, bye.
MOLLY BLOOM: Bye. Close the door you guys.
MARC SANCHEZ: On the road again. Say goodbye to my little pika friend.
SANDEN TOTTEN: Marc?
MARC SANCHEZ: Sorry. I can't help it. Road trips make me singing. Laugh at the highway. I want to run it all day long. Wait, whoa. Watch out up ahead. There is something in the road.
YAK: Frankie. Frankie.
[WINDOW OPENS]
SANDEN TOTTEN: Wow, those are some furry cows.
MOLLY BLOOM: Oh, those are yaks.
NAKS: And naks. Female yaks are called naks.
MOLLY BLOOM: Oh, my apologies. Your fur looks very warm.
NAKS: It is. It keeps us warm at up to -40 degrees Fahrenheit. We also have huge lungs so our body can capture lots of oxygen from the thin air. Then our huge heart helps pump that oxygen in our blood around our body, which keeps us warm.
MARC SANCHEZ: My, what big horns you have?
NAKS: Better to smash the snow with, my dear. We eat the greens underneath and lick moss and lichen off of rocks with our scratchy tongues.
MARC SANCHEZ: Ooh, wow.
BAXTER: Hey, look. There's mountain goats too. See, those white animals up there walking on the sheer rock wall.
MARC SANCHEZ: Wow. How do they do it?
MOLLY BLOOM: Ooh, their hooves are cloven so they spread wide for amazing balance. Young goats can even start scrambling around the day after they're born.
MARC SANCHEZ: Oh, cool. Let's go say Hello. I want to meet them.
MOLLY BLOOM: Maybe not. Female mountain goats can be vicious if they think you're threatening they're young, and that one has a kid.
MARC SANCHEZ: That doesn't sound like a kid to me. Get some more like this. I have so much energy. I'm a little kid. I didn't even have any coffee. This is just what it's like to be me. Whoa.
MOLLY BLOOM: Baby mountain goats are called kids.
MARC SANCHEZ: Oh.
SANDEN TOTTEN: I thought high up on a mountaintop you, wouldn't find any wild animals. But given all the wildlife we've seen, I was clearly wrong.
MOLLY BLOOM: Totally. Now, let's go. We are almost at the top.
SANDEN TOTTEN: So come on, let's drive, drive, drive.
MARC SANCHEZ: Look, who's singing now?
MOLLY BLOOM: Woo. Yeah.
[WIND BLOWING]
We finally made it. Oh, what a view up here?
SANDEN TOTTEN: Yeah, I think I can see headquarters. And wait, is that Gungador using my eyebrow brush again? Hey, you lovable monster. Get your own brow brush.
BAXTER: Sure it's cold though.
MOLLY BLOOM: Yeah, good thing I packed a pack of purple and pink power parkas. Perfect for pairing off pretty peaks.
MR BART: Ice cream. Ice cream. Live the dream with ice cream.
MARC SANCHEZ: Ooh, ice cream.
SANDEN TOTTEN: Ice cream all the way up here?
MR BART: Yes, sir. Indeedy Doody. I've got flavors from chocolate to fruity. Want a snack but forgot to pack? I've got you covered. I've got your back. Get ready for a flavor attack.
MARC SANCHEZ: Who is this dude?
MR BART: It's me. Hello, I'm Mr Bart. The rhyming dancing ice cream cart guy.
BAXTER: Mr. Bart, don't you think it's a little cold for ice cream?
MR BART: I thought up here so close to the sun, it's sure to be hotter than a hot cross bun. But Lo and behold, on a mountaintop, it's frostier than my frostiest pop.
BAXTER: Yeah, it's hot. I mean, hot air rises and we're closer to the sun. So why is it that it's so cold? I've always wondered that.
MOLLY BLOOM: Our listeners wondered that too. Actually, I think I brought their questions with me. Yeah, here, in this jar. Let me unscrew the cap.
BEN: My name is Ben from Los Angeles, California.
NORA: My name is Nora from Omaha, Nebraska.
OLIVER: My name is Oliver from Phoenix, Maryland.
MAGENTA: My name is Magenta. I'm from Brisbane in Australia.
NORA: If hot air rises.
MAGENTA: Why does it get colder when you go higher?
BEN: A few years back, we went to the Rocky Mountains and it was super cold up there but we forgot warm clothes.
OLIVER: I went on a camping trip to Arizona. We went to a higher elevation and it was really cold while the desert was hot.
MAGENTA: When you climb a mountain, shouldn't it be warm up because you're closer to the sun?
BAXTER: Whoa. Great questions.
SANDEN TOTTEN: Yeah, I also have some questions. How did you get those into a jar?
MARC SANCHEZ: Yeah, I can help explain this one. There are actually a bunch of reasons why it's colder on top of mountains. I was just talking to my pal Deanna Hence about this.
MOLLY BLOOM: Oh, Deanna Hence? Assistant professor of Atmospheric Science at the University of Illinois, Urbana-Champaign?
MARC SANCHEZ: Yeah, her.
MOLLY BLOOM: Cool. What did she say?
MARC SANCHEZ: Well, she told me a lot of it has to do with how hot air works in general. You see hot air comes from the sun warming up the ground, and that warm ground then passes that energy to the air around it, which sounds a little hard to picture, but sometimes you can actually see it happening. How did she explain it? Oh, wait, I have her explanation here in this ziploc bag.
DEANNA HENCE: So you can see this probably most dramatically when you're out in a desert and you say, looking at a road, and you're seeing it be all shiny. Well, that shininess is a mirage. And the reason why that mirage is actually happening is because the air that's immediately above the ground is being heated by the ground and that's actually changing how light bends through the air.
MARC SANCHEZ: So if you see a mirage on some concrete on a hot day, you're just seeing the ground heating up some low lying air. Cool, right? I mean, hot, right?
BAXTER: Very. I didn't know that about mirages.
SANDEN TOTTEN: And I did not know you could put a voice into a ziploc bag. Can you tell me how--
MARC SANCHEZ: Yeah, so that hot air it rises and it expands. Which means it goes up and wants to spread out. But here's what happens as it does that. Is that bubble of hot air floats up, it becomes surrounded by cooler and cooler air, and it starts to lose its energy, its heat. Oh, think of it like this. Picture of bounce house full of rowdy kids.
The kids are like the excited air molecules full of energy, which makes them shoot around really fast. The pocket of warm air is like the bounce house. Now, as these kids bounce around, boing, boing, boing, they actually push against the bounce house so hard they stretch it out making it bigger and bigger.
BAXTER: Just like the warm air expands as it rises.
MARC SANCHEZ: Exactly. But stretching out that bounce house, as you can imagine, that's a lot of hard work, and it takes a lot of energy. So the longer these kids do it, the more tired they become until eventually they're pooped.
What that means for hot air is as it expands and rises, it uses up all its energy a.k.a. its heat, and eventually it cools down. That happens way before it reaches a mountaintop. So even though hot air rises, it doesn't have enough energy to go from the ground all the way to the tippy top of a tall mountain. So that's part of why it's cold up here.
MR BART: But riddle me this, my learned fellow. Take a look around. We are up high. That is true. But we are also on the ground. Wouldn't the sun warm this too creating hot air on this peak? If so, then why have I been so cold selling ice cream here all week?
MARC SANCHEZ: Great follow up, Mr. Bart. You see the sun is warming the ground here, too. But the answer you seek has to do with the peak.
MR BART: That rhyme was nice. My home slice.
MARC SANCHEZ: I know, right? Here, Deanna explain this to me too, and I think I brought an explanation in this pocket. Oh, shoot. No, no. That's my tap dancing elephant sound, better put that back. Whoa, not that pocket. Here we go. She said when you're on a peak, you have ground under you but not as much around you.
DEANNA HENCE: Because you're on a slope and you're basically exposed to air that's not touching the ground. If you think about if you're like standing in a field in a very flat space. If you're getting a breeze across your face, all that air has had time to just travel over just miles and miles and miles of warm land.
As it's doing that, it's picking up heat from the ground as it's traveling over the ground. If you're at the top of a mountain, yeah, maybe the little pocket that's right around you maybe getting heated by the ground that you're standing on. But a lot of the air that's coming from that breeze, it's all coming from stuff that's not touching the ground.
MARC SANCHEZ: And that other air the stuff around the peak it's cold. And it makes the breeze and the air up high pretty cold, too. Wow
MOLLY BLOOM: That. Answer deserves a standing ovation. I have one here in my wallet.
[APPLAUSE]
SANDEN TOTTEN: OK. Am I the only one who isn't carrying sounds with them at all times?
MARC SANCHEZ: As for the sun, yeah we're closer. But given how far the sun is from the planet, we're really not close enough to make a difference heat wise. These are just some of the reasons it's cold on top of a mountain and why you Mr. Bart probably should have sold hot chocolate instead of frozen fudgicicles.
MR BART: Wow. I feel so much smarter having learned about air and atmospheric science. Now, excuse me while I move my cart and something rhymes with science. Bye.
MOLLY BLOOM: Wait, Mr. Bart, will you join us for our group photo?
MR BART: I thought you'd never ask. Being in photos is my favorite task.
SANDEN TOTTEN: Ooh, let's get the mountain animals in on this too.
MARC SANCHEZ: OK, huddle in everybody. Hey, yak and nak, you're blocking Baxter, so scooch over just-- OK, perfect right there. All right. Say cheese.
ALL: Cheese
MR BART: If you please.
MOLLY BLOOM: And stick around for the answer to the mystery sound in just a moment.
BAXTER: Mountains forming tectonic plates crash into each other or overlap.
MOLLY BLOOM: This takes millions and millions of years and some mountains are still growing today.
BAXTER: Volcanoes are also a type of mountain.
MOLLY BLOOM: Mountains are full of wonder animals that have special features that help them survive a high.
BAXTER: Even though the hot air rises, the air loses energy as it floats up so mountain tops are usually very cold.
MOLLY BLOOM: That's it for this episode of Brains On.
BAXTER: This episode was produced by Molly Bloom, Rosie DuPont, Ruby Guthrie, Marc Sanchez, Sanden Totten and Menaka Wilhelm.
MOLLY BLOOM: Our fellow is Anna Goldfield and our executive producer is Beth Pearlman. We had engineering help from Johnny Vince Evans, Noah Cole, and Peter Starkey. The executives in charge of APM Studios are Lilly Kim, Alex Shaffer, and Joanne Griffith. Special thanks to Rick and Kari Thackery and Anna Weigel.
BAXTER: Brains On is a nonprofit public radio program.
MOLLY BLOOM: There are lots of ways you can support the show. You can donate by our books or tell your friends about us.
BAXTER: Head to brainson.org to find the links to donate and buy the books.
MOLLY BLOOM: And remember, you can find an answer to the Moment of Um question, do mice really like cheese? on the Moment of Um podcast. Before we go Baxter, are you ready to hear that mystery sound one more time?
BAXTER: Yes.
MOLLY BLOOM: Here it is.
[SQUISHING]
Any new thoughts?
BAXTER: I think my first guess was right, like the sticking the foot and something sticky.
MOLLY BLOOM: Do you have any thoughts about what that sticky substance might be?
BAXTER: Maybe mud, but I'm not sure.
MOLLY BLOOM: It's true. Our listeners like to stump us with their mystery sounds. So it could be jello for all we know. Are you ready for the answer?
BAXTER: Yes.
MOLLY BLOOM: Here it is.
MAISIE: Hi, my name is Maisie and I'm from Petaluma, California. And that was the sound of me stepping in mud. I made it squishier by mixing more mud together with it. It's very sticky.
MOLLY BLOOM: Baxter, nice work.
BAXTER: Thanks.
MOLLY BLOOM: So have you walked through mud yourself?
BAXTER: Yes, there's been a lot of mud with the snow melting, then more snow falling than all that snow melting, and then it raining, and then more snow than that snow melting.
MOLLY BLOOM: You do a lot of experience with mud.
BAXTER: Yeah.
[THEME MUSIC PLAYING]
MOLLY BLOOM: I am very excited to read this list of names. It's time for the Brains Honor Roll. These are the incredible listeners who send us their drawings, mystery sounds, questions, and high fives.
[LISTING HONOR ROLL]
[THEME MUSIC PLAYING]
We'll be back soon with more answers to your questions.
BAXTER: Thanks for listening.
Transcription services provided by 3Play Media.
