Apples are a delicious treat! These crispy crunchy sweet snacks are everywhere: in our school lunches, at the farmers market, even covered in caramel at the fair. But as Molly and cohosts Jack and Penelope find out, growing an apple is a lot harder than it sounds. In this episode, we’ll learn how bears and horses helped the first wild apples grow (in their poop!) and meet the world’s biggest apple fan, Johnny Appleseed. Plus, even an apple a day can’t keep a brand new Mystery Sound away!

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PENELOPE: You're listening to Brains On! where we're serious about being curious.

NARRATOR: Brains On! is supported in part by a grant from the National Science Foundation.

MOLLY BLOOM: Hey, friends. It's me, Molly, in the studio with Penelope and Jack. Say hi Penelope and Jack.

PENELOPE AND JACK: Hi.

MOLLY BLOOM: We're all blindfolded right now, right?

PENELOPE: Yep.

JACK: Yep.

MOLLY BLOOM: Can't see anything.

PENELOPE: Correct.

MOLLY BLOOM: OK. Great. Because we're about to do an apple taste test. Our producer Shahla has a selection of apples picked out for us. And we're going to do our best to describe them using only our taste buds. Are you ready?

PENELOPE: Yeah.

JACK: Yes.

MOLLY BLOOM: OK. Shahla, please give us our first apple.

SHAHLA FARZAN: So we've got our blindfolds on. And I'm going to hand you a slice of apple. And then on the count of three, you'll take a bite. Ready? 1, 2, 3.

[CRUNCHY SOUND]

MOLLY BLOOM: Mhm. Oh! That's really tart. OK. Ooh!

SHAHLA FARZAN: What does it taste like to you? Let's start with Jack.

JACK: It tasted a bit sweet to me.

PENELOPE: It tastes kind of like a Sour Patch Kid because it was sour and now it's sweet.

MOLLY BLOOM: Mhm. Yeah. I'm getting that too. Would you describe it as crunchy? Soft?

JACK: Both.

MOLLY BLOOM: OK. So Jack, if you had to name this apple based on how it tastes. What would you call it?

JACK: Maybe a Granny Smith apple.

MOLLY BLOOM: Oh, very good. How about you, Penelope? What would you name it? You could give it your own name, even maybe you don't know the real name. You could name it whatever you want.

PENELOPE: Sour Patch Kid apple.

MOLLY BLOOM: You know what, that would fly off the shelves. People would love that. OK, Shahla, what was the apple?

SHAHLA FARZAN: That apple was a Granny Smith.

MOLLY BLOOM: Hey, Jack.

JACK: Yeah.

MOLLY BLOOM: You are an apple connoisseur. I think they should rebrand to be Sour Patch Kid apples, just saying. OK.

SHAHLA FARZAN: Agreed.

MOLLY BLOOM: Let's do the next apple.

SHAHLA FARZAN: OK. Are you ready? On the count of three, we're going to take a bite again. Ready? 1, 2, 3.

[CRUNCHY SOUND]

MOLLY BLOOM: All right. It tastes like an apple.

PENELOPE: It tastes very sweet. It's not as sour as the last one.

JACK: Yeah. What she said it kind of jumped straight to sweet instead of going sour than sweet.

MOLLY BLOOM: What about the texture? How would you describe the texture of this one?

JACK: It was similar to the last one.

PENELOPE: Yeah. It's kind of crunchy at first, but then it gets like really soft.

MOLLY BLOOM: What would you name this? Either real apple or your own name for it.

JACK: I think it might be like a Red Delicious apple.

MOLLY BLOOM: OK. Penelope, you want to invent a name?

PENELOPE: The Not Sour Patch Kid apple.

MOLLY BLOOM: [LAUGHS] I like it. You're not in the mood for sour. Should we find out what it is?

PENELOPE AND JACK: Yeah.

MOLLY BLOOM: Shahla, what is this apple?

SHAHLA FARZAN: That apple was a Pink Lady apple.

MOLLY BLOOM: Mmm. Let's do our third apple.

SHAHLA FARZAN: 1, 2, 3. Bite.

[CRUNCHY SOUND]

MOLLY BLOOM: Mhm. All right, Penelope, what do you think?

PENELOPE: This one tastes really sweet. Not even sour at all, just sweet.

MOLLY BLOOM: It's very sweet. Yeah. What do you think, Jack?

JACK: Yeah. This one's very sweet. It had, it was more flavor than the last one.

MOLLY BLOOM: What about texture wise?

JACK: I think it felt like the same as last time, crunchy and then pretty soft.

MOLLY BLOOM: Yeah. It gets soft pretty fast for me.

PENELOPE: Yeah. It got soft way faster than all the other ones, though. It went like oh my god it's soft.

MOLLY BLOOM: Yeah. OK. What will we name this apple?

PENELOPE: The Sweet Tart apple because this one's really sweet.

MOLLY BLOOM: Sweet tart. I love it. You should go into apple naming for your job, I think. Jack, do you have a creative name that you could come up with for this one? Let's see if you could also have that job.

JACK: Probably the Sweet Mushy apple.

MOLLY BLOOM: [LAUGHS] The Sweet Mushy apple. I love it. Very honest, maybe not a big seller.

SHAHLA FARZAN: Probably not.

MOLLY BLOOM: But it's truth. It's truth. I like it.

JACK: Just describing it.

MOLLY BLOOM: Yeah. That's good. People should know what they're getting. All right. Shahla, what is it?

SHAHLA FARZAN: OK. That last apple was called a Cosmic Crisp.

MOLLY BLOOM: Whoa! Very--

JACK: Sounds like something from a Mario game.

MOLLY BLOOM: Yeah. It totally does. Shahla, fourth and final apple. We're ready.

SHAHLA FARZAN: Ready to take a bite?

PENELOPE: U-huh.

JACK: Yep.

SHAHLA FARZAN: 1, 2, 3. Chew.

[CRUNCHY SOUND]

MOLLY BLOOM: That is not sweet.

PENELOPE: It tastes like a carrot.

MOLLY BLOOM: It's kind of like a little bitter.

PENELOPE: Very bitter.

MOLLY BLOOM: Something is wrong with this apple. [LAUGHS]

PENELOPE: I think it might have pickled.

MOLLY BLOOM: Pickled apple?

[LAUGHTER]

SHAHLA FARZAN: I just had to keep you guys on your toes. That one was technically not an apple. That was a radish. We were testing your taste buds.

JACK: Yeah. OK.

MOLLY BLOOM: (WHISPERING) How could you? How could you not tell us? [LAUGHS] All right. Let's get these blindfolds off and start the show.

[THEME MUSIC]

You're listening to Brains On! from APM Studios. I'm Molly Bloom. And today, I'm here with Jack and Penelope from St. Louis. Hi, Jack and Penelope.

PENELOPE AND JACK: Hi.

MOLLY BLOOM: Thank you for eating some apples and a radish with us this morning. Really appreciate it. I am apple-solutely delighted you're both here. Because today's episode is all about them, apples. And it was inspired by a bushel of questions including this one.

GIRL: My question is, how are apples made?

PENELOPE: We had a question about that too.

JACK: Yeah. We wanted to know if you plant an apple, why does it grow a tree and not just an apple itself?

MOLLY BLOOM: So Jack and Penelope, what made you think of this?

JACK: I was just wondering because like carrots, they grow in the ground. I was like, why do apples grow on trees? Why can't they grow in the ground like carrots?

MOLLY BLOOM: Good question. Have you gone apple picking before?

PENELOPE: Yes.

JACK: Yeah. We do it almost every like fall.

MOLLY BLOOM: Do you like it? Do you like going apple picking?

PENELOPE: Yeah.

JACK: Yeah.

MOLLY BLOOM: I've never been apple picking, guys. I've never been. So please--

JACK: Never?

MOLLY BLOOM: Describe it to me.

PENELOPE: You go walking around this giant field full of apple trees. And you get to look at all the apples on the trees and pick out the ones that are perfect.

MOLLY BLOOM: You need like a ladder to pick them or are they low enough that you can just grab them?

JACK: They're usually low to the ground. And if you need to get to one of the ones that are higher, you just grab your tall friend and get them down for you.

MOLLY BLOOM: Hey, tall friend. Please give me that apple. That's a good plan. Apples are a super popular snack and we're used to seeing them everywhere.

PENELOPE: At the grocery store.

JACK: At the farmer's market.

PENELOPE: In our school lunches.

JACK: And covered with caramel at the fair.

PENELOPE: In our pies.

JACK: And in our cakes.

MOLLY BLOOM: Right. And they are so common that you might think they're easy to grow. But it actually takes a lot of time, hard work, and even a little luck to grow an apple. Here's the first thing that's tricky about them. Most apples you buy from the store weren't actually grown from an apple seed.

JACK: Hold on a second. How are in the apple strudel are we growing apples if we can't get them from seeds?

MOLLY BLOOM: I know. It's bananas or rather apples. It's not that you can't plant an apple seed. You can and it very likely will grow a tree full of fruit. But those apples probably won't taste like the apple you started with.

Like let's say you were snacking on one of those super tart Granny Smith apples. And you decided to plant the seeds. You could grow a tree from those seeds. But the apples on that tree wouldn't even be close to the same tart green one you started with.

PENELOPE: Really? That's wild!

MOLLY BLOOM: Really, truly. And it's not just apples. A lot of fruits act this way, everything from pears to cherries. It's because those plants have seeds full of lots and lots of DNA.

JACK: Oh yeah. DNA is like the instruction manual for how to make a living thing, whether it's a peacock, a pineapple, or a person.

MOLLY BLOOM: Right. But here's what makes apples and some other fruits special. Inside that Granny Smith apple from before, there's the instructions to make more Granny Smiths. But there's also instructions to make lots of other kinds of apples too-- yellow ones that are bitter or red ones that are sweet.

PENELOPE: So if there are many different instructions inside an apple, how does the tree know which one to make?

MOLLY BLOOM: It doesn't. It all happens randomly. That's why when you plant a seed, you don't know what instructions the tree will be working with to make its apples. It's like a game of chance.

PENELOPE: Or like Halloween!

MOLLY AND JACK: Halloween?

PENELOPE: Yeah. Let's say you went trick or treating on Halloween but only went to two houses. One gave you chocolate bars and the other gave you gummy bears. If you reached into the bag without looking and picked up a handful of candy, you'd get--

JACK: Chocolate and gummy bears.

PENELOPE: Right or all chocolate or all gummy bears. There aren't a whole lot of combinations. Now, imagine you visited lots of houses. And they all gave out a different type of candy-- caramels, cookies, gumballs, raisins.

JACK: Oh and Snickers. That's my favorite.

MOLLY BLOOM: Oh and Junior Mints. That's my favorite.

PENELOPE: Exactly! All kinds of candy, maybe even a toothbrush from the dentist down the street.

JACK: For the record, toothbrushes aren't treats.

MOLLY BLOOM: Floss on the other hand, a true delight.

PENELOPE: Now, imagine you reached into your bag and grabbed a handful of candy.

JACK: There's so many different combinations. There's no telling what you would get. Will it be mostly chocolate stuff or sour stuff or chewy things or hard things?

PENELOPE: Exactly. Just like apple seeds. The seeds are like the candy bag and the DNA is the different pieces of candy. Each time you plant a seed, it's like picking out a different handful of candy. There's no telling what combo you're going to get.

JACK: So growing an apple from a seed is really unpredictable, which means you can't use seeds to grow the kinds of apples you see at the grocery store. So how do we make those apples then?

MOLLY BLOOM: Well, here's something I learned the other day that really shook me to my core. Most apples are copies.

PENELOPE: So my apple is just a knockoff apple? Is it even real?

MOLLY BLOOM: Well yes, no. Apples are very real. Lots of fruits including apples are grown using a technique called grafting.

PENELOPE: Sounds crafty.

MOLLY BLOOM: It is. You can think of it like making a plant collage. Farmers pick an apple tree they like, maybe one that makes really sweet fruit and snip off a branch from that tree. Then they take that branch and stick it onto the root of another apple tree.

JACK: Like a plant puzzle.

MOLLY BLOOM: That's the idea. Once the farmer sticks the two tree parts together, they have to wait for them to grow a bit more. But eventually, that branch from the first tree starts growing on its own. It becomes a sapling or a baby tree.

PENELOPE: Whoa! Crafty grafting.

MOLLY BLOOM: But even then, you don't get apples right away. First, the sapling has to grow strong enough to support heavy apples which can take up to eight years.

JACK: That's a long time to wait for apples.

MOLLY BLOOM: And that's not the half of it. Once the trees are ready, it takes months for an apple to grow. First in the spring, the tree makes a flower. Then a bee or other bug will come along and snag some pollen from that flower and spread it to other flowers.

PENELOPE: Oh yeah. That's called pollination. It's how fruit happens.

MOLLY BLOOM: Exactamundo. Once the flying critters spread that pollen, we say the flowers are pollinated. Then the flowers start growing into fruits. And some can be ready to be picked in just about three months, while others aren't ready until the late fall.

PENELOPE: That seems really complicated. How did people first figure out how to graft trees? And how flowers needed to be pollinated?

MOLLY BLOOM: Well, we don't entirely know for sure. A long time ago, apples didn't look or taste like the ones in your lunchbox today. They had to go through a lot of changes and travel over hundreds of miles. You know what? I just watched the best food history documentary all about this. One second. Let's see if I still have it up on my TV.

VICTORIA: I'm Victoria [INAUDIBLE], and this is very delicious histories. Our story begins around 5 million years ago in the beautiful Tian Shan mountains in Central Asia also known as the Heavenly Mountain.

During this time, bears were moving into the mountains. They came to hang out in the caves and forests where they got to eat lots of yummy bear snacks. Some of their favorite treats, wild apples.

BEAR: (SINGING) An apple for you. An apple for me. 20 little apples in my tummy.

VICTORIA: As the musical bear just noted, these early apples were small, very small, probably around the size of a grape. And it's doubtful that all of them tasted very good. But over millions of years, scientists think bears kept picking out the biggest and sweetest apples to eat.

BEAR: Whoa! (SINGING) One apple, two apple, apple three. Give me the juiciest apples that you see.

VICTORIA: Now get this, because bear jaws are big their teeth are not very good at smashing up the seeds inside those apples. So the apple seeds would slip down their throats as they ate and come out the other end in perfect shape surrounded by top notch fertilizer.

BEAR: She needs my poop.

VICTORIA: Oh that word is so unrefined. Pardon my friend here. As you know, bears don't have any manners.

BEAR: Oh poop, poop, poop.

VICTORIA: As I was saying, bear feces helped these perfect little apple seeds grow into trees. And the more bears ate, the more they relieved themselves--

BEAR: Today's poop.

VICTORIA: Yes and the more these apples spread throughout the mountains. And since these bears tended to eat the juiciest, biggest apples, these new trees grew big juicy apples too.

BEAR: Grown from my poop.

VICTORIA: All right. We get it. Enough of the poop talk. Let's fast forward a few million years to around 2000 years ago. Goodbye, bear.

BEAR: Poop!

VICTORIA: It's all right, Victoria. Stay focused. Now, around this time, humans were traveling through the Tian Shan mountains along what is known today as the Silk Road. And they had brought horses and donkeys with them. And these animals also really liked eating apples, especially the big sweet and juicy kind. As they traveled through the mountains, they left apple seeds along the way.

HORSE: In our poop.

VICTORIA: Oh for Pete's sake. This again? Yes. And without even knowing it, they were pushing the apple seeds into the ground with their hooves basically planting them.

HORSE: In our poop.

VICTORIA: If I hear that word one more time. Pardon moi. So humans traveled farther and farther west into a part of the world that came to be known as the Fertile Crescent. This is the moon shaped slice of land around the Tigris and Euphrates rivers in what's now the Middle East, home to some of the earliest human civilizations.

And like before, the apple seeds came with them. These bigger, juicier apples took root in the Fertile Crescent. And when the ancient Romans discovered them more than 2000 years ago, they began growing them for taste.

As Roman armies stormed into the rest of Europe, they planted orchards. And soon, apples were all the rage in France, England, and other parts of Northern Europe.

WOMAN: I say taste this apple cider I made. Isn't it rather delicious?

VICTORIA: That's more like it. Now, these people have manners.

WOMAN: Apples are ever so scrumptious. And they're so full of fiber, really helps with your bowel regularity. Meaning, they help you poop.

VICTORIA: Oh for the love of-- breathe, Victoria. In. Out. OK.

So by the 1500s, when British and Spanish colonialists started shipping out to places like the Americas, settlers brought apples and apple seeds with them. Because apples are delicious.

WOMAN: And they make you poop.

VICTORIA: Oh, that is it! Find someone else because I quit. Victoria, Victoria's out.

MOLLY BLOOM: Wow! I did not see that coming. I for one adore talking about poop.

PENELOPE: I think I need a palate cleanser after that.

MOLLY BLOOM: Would the mystery sound work?

PENELOPE AND JACK: Yeah.

MOLLY BLOOM: Hoo hoo! I love the enthusiasm. Here it is.

[CLICKING SOUND]

OK. What is your guess? Let's start with you, Penelope.

PENELOPE: It sounded like someone was banging on a table or something.

MOLLY BLOOM: Mhm. Absolutely. What about you, Jack?

JACK: Maybe like a hammer and nail or something like that.

MOLLY BLOOM: Do you have any thoughts about why somebody would be banging on a table?

PENELOPE: To get someone's attention, maybe.

MOLLY BLOOM: Like hey, I need some more apples. Come on. You love it. All right. Well, we are going to hear it again. Get another chance to guess and hear the answer after the credits.

PENELOPE: So stick around.

JACK: What she said.

[UPBEAT MUSIC]

MOLLY BLOOM: Hey, friends. We are working on an episode about why we're sometimes afraid of the dark. But the dark is also totally cool. So we want to know what do you love about the dark? Does it feel mysterious, exciting? Do you like telling stories around a campfire? Are you a night owl? Do you think nocturnal animals like possums are awesome?

Listeners, we want to hear from you. Record yourself describing what you love about the dark and send it to us at brainson.org/contact. While you're there, you can also send us mystery sounds, drawings, high fives, and questions.

JACK: Like this one.

GIRL 2: My question is, how did colors get their names?

MOLLY BLOOM: You can find an answer to that question on our Moment of Um podcast. It's a daily dose of facts and curiosity you can find wherever you listen to Brains On! Again, that's brainson.org/contact.

PENELOPE: So keep listening.

You're listening to Brains On! from APM Studios. I'm Penelope.

JACK: I'm Jack.

MOLLY BLOOM: And I'm Molly.

JACK: So we learned it takes a lot of work to make sure the apple you are growing is the apple on want.

MOLLY BLOOM: Yeah. Apples are a wild card fruit. Their seeds have so much DNA. They can grow pretty much any kind of apple. And there's no guarantee that if you plant a seed from a Fuji apple, you'll get a Fuji apple tree. So most growers make copies of trees using a special technique called grafting.

PENELOPE: Apples had a long journey to America. They traveled all along the Silk Road with some pit stops and bear and horse poop along the way

JACK: It's pretty funny when you think about it. People like to say things are American as apple pie. But it turns out apples are kind of from all over.

PENELOPE: And fun fact, apple pie is actually from England.

MOLLY BLOOM: One reason Americans want to lay claim to apples might be the legend of Johnny Appleseed. I remember when I was a kid, I saw this cartoon about Johnny Appleseed made by Disney. He went across the country planting seeds and singing songs. Did you guys ever see that cartoon?

PENELOPE: I don't remember seeing it.

MOLLY BLOOM: Yeah. It's an old, it was old when I was little. So it's very old now for you. Do you know anything about Johnny Appleseed?

JACK: Yeah. Well at least from what we've read and stuff. He walked around with a pan and like picked apples from trees and stuff and made apple pie.

PENELOPE: All I know is that his name is Johnny Appleseed.

MOLLY BLOOM: That's it?

PENELOPE: Yeah. That's it.

JOHNNY APPLESEED: Oh, hey, dudes. I heard you were talking about me?

MOLLY BLOOM: Who are you?

JOHNNY APPLESEED: John Chapman but you might know me better by my stage name Johnny Appleseed.

PENELOPE: Hold on. I thought Johnny Appleseed was a myth.

MOLLY BLOOM: Yeah like Paul Bunyan or Uncle Sam.

JACK: Or Bigfoot.

JOHNNY APPLESEED: Nope I'm 100% bona fide. Johnny Appleseed, a real person.

PENELOPE: What's with the pot on your head?

JOHNNY APPLESEED: Oh you like it? People have told all sorts of stories about me over the years to the point where I don't even remember what's true and what's not. Anyway, one day I heard someone say I wear a tin pot as a hat. So I decided to try it myself. I mean, it looks pretty cool. Am I right?

JACK: Does it?

JOHNNY APPLESEED: It totally does, which got me thinking, I should start selling these tin pot hats. Think of it like this, are you ever walking through the woods or sitting in the middle of class, and all of a sudden your stomach starts growling.

Well, with one of my tin pot hats, your tummy will be rumbling no more. You're seconds away from soup, minutes from mac and cheese. You got a superhighway to snackage right on top of your noggin.

PENELOPE: But wouldn't you also need a box of mac and cheese? Or a can of soup with you?

JACK: Yeah. And a way to heat it up? At this point, I might as well just pack a lunch instead.

JOHNNY APPLESEED: Ha ha. I know, right? I'm so brilliant. Now I'll have to do is start a company. And these babies will be flying off the shelves. I was thinking of naming it after my favorite fruit, apple.

JACK: Hey, Johnny, I think that might already be taken.

JOHNNY APPLESEED: My company will be bigger, sleeker. And every shop will be white.

MOLLY BLOOM: But speaking of apples, Johnny, how did you get into the apple planting business?

JOHNNY APPLESEED: Oh right. It started way, way, way, way back, like more than 200 years back, in the early 1800s.

MOLLY BLOOM: Oh yeah. This was way before cars, TV, the internet, electricity, or phones. People wrote letters and farmed a lot and traveled by horse drawn carriages.

JOHNNY APPLESEED: Yeah, the simple life. I was minding my own business in Western Pennsylvania when I heard something interesting.

MAN: Listen up. Have I got a deal for you.

JOHNNY APPLESEED: It turns out, some company was trying to get white settlers like me to move out west.

MAN: Hear ye. Hear ye. If any of you put up a permanent homestead, we'll give you 100 acres. No strings attached. All you got to do is plant an orchard-- 50 apple trees and 20 peach trees.

MOLLY BLOOM: Right. At that time, most white Americans believed that the land out there was waiting for them. But in reality, Native Americans were already living there. Companies like these were encouraging white settlers to put down roots so they could claim the land as their own.

PENELOPE: That sounds pretty unfair.

JOHNNY APPLESEED: It was. But back then, all I was thinking was, why not? I love being outside. I was sick of the corporate grind. I figured I could help settlers by planting trees and make some money on the side too. And I love me some apples. So I grabbed a bag of apple seeds, kicked off my shoes, and set out into the wilderness.

[COUNTRY MUSIC]

I walked out to places where I thought people might want to settle. And I planted apple trees there. When settlers finally came, I saw the orchards to them and then moved on. Plant, sell, move. Repeat. Over and over, just like that.

JACK: That's quite the moneymaking scheme.

JOHNNY APPLESEED: Go ahead, try an apple.

JACK: OK.

PENELOPE: OK.

MOLLY BLOOM: OK.

PENELOPE: What was that?

MOLLY BLOOM: That's disgusting!

JACK: Are you sure that's an apple?

JOHNNY APPLESEED: Oh yeah. These apples were gross. That's what we call a spitter because the second you bite into it, you got to spit it out immediately.

PENELOPE: Thanks for the warning.

JOHNNY APPLESEED: Homesteaders weren't really concerned with taste because they weren't even eating apples like we were or baking them into pies. We mainly drank them. Back then, you couldn't really always tell if water and rivers and streams were safe.

So lots of people squeezed the juice out of the apples. If you left it long enough, the juice went through the process called fermentation. Fermentation killed bacteria and made alcohol leaving the people with safe to drink apple cider.

MOLLY BLOOM: Where's one of those good apples from the start of the show? I need to get this taste out of my mouth.

JOHNNY APPLESEED: Sorry about that. But over the years, my trees helped increase the diversity of American apples, which helped them survive all kinds of diseases and pests. Eventually, apples got better tasting too.

JACK: Hold on. So the apples we eat today probably owe something to the ones you planted 200 years ago?

JOHNNY APPLESEED: Exactamundo. People started growing apples that could taste good on their own in the 1900s, grafting delicious apple branches onto strong spitter apple trees to make hearty, yummy eating apples. But that was way after my time. So I should probably stop talking now. Gotta head back to the past to plant more apples.

Later science friends. Come see me anytime if you want an apple that tastes terrible.

[UPBEAT MUSIC]

PENELOPE: Apples can be a tricky fruit to grow. An apple seed can grow a tree with many different kinds of apples, some delicious and some not.

JACK: So growers make copies of the tasty apple trees using a technique called grafting. That way they know what apple they're going to grow.

PENELOPE: Even after grafting, apple trees need a lot of care. It takes years for them to become big and strong.

MOLLY BLOOM: Apples as we know them had a long journey from the Tian Shan mountains in Central Asia to America. It was only with the real Johnny Appleseed's help that they spread across the United States. That's it for this episode of Brains On!

PENELOPE: This episode was produced by Molly Bloom.

JACK: Anna Goldfield.

PENELOPE: Molly Quinlan.

JACK: Rosie DuPont.

PENELOPE: Aron Woldeslassie.

JACK: Anna Weggel.

PENELOPE: Nico Gonzalez Wisler.

JACK: Ruby Guthrie.

PENELOPE: And Marc Sanchez.

MOLLY BLOOM: Our editors are Sanden Totten and Shahla Farzan. This episode was sound designed by Rachel Brees. Beth Pearlman is our executive producer. The executives in charge of APM Studios are Chandra Kavati, Alex Schaffert, and Joanne Griffith.

Special thanks to Cindy Collins, Teresa and Jake LaMora, Shruti Acharya, Howard Means, Kate Evans, Lee [INAUDIBLE] and Matthew Whiting.

JACK: Brains On! is a non-profit public radio program. There are lots of ways to support the show. Head to brainson.org.

PENELOPE: While you're there, you can send in your mystery sounds, questions, and drawings.

MOLLY BLOOM: You can also subscribe to our Smarty Pass.

JACK: Super fun, ad-free episodes, and bonus stuff just for you.

MOLLY BLOOM: OK. Jack, Penelope, are you ready to hear the mystery sound again?

PENELOPE AND JACK: Yes!

MOLLY BLOOM: Yo yes! So enthusiastic. OK. Here it is.

[CLICKING SOUND]

All right. New thoughts?

PENELOPE: It kind of sounds like a stapler or something.

MOLLY BLOOM: Yeah, totally. That's the sound of the stapler like going down and stapling the papers. You like that? Jack, what do you think? Any new thoughts?

JACK: Maybe like a nail gun or something like that.

MOLLY BLOOM: OK. OK. Similar thing, but just more powerful than a stapler. I'm going to stick with my original guess of someone banging on the table saying more apples. Should we see what the answer is?

PENELOPE AND JACK: Yes.

MOLLY BLOOM: OK. Here it is.

AMALIA: Hi. I'm Amalia. I'm 8 and I live in Portland, Oregon. That was the sound of me pressing on a stapler.

MOLLY BLOOM: Oh! Penelope!

JACK: Yeah!

PENELOPE: I have good ears.

MOLLY BLOOM: Yes you do. Nice work. I'm shocked it wasn't someone asking for more apples.

[CLICKING SOUND]

Now it's time for the Brains Honor Roll. These are the incredible kids who keep the show going with their questions, ideas, mystery sounds, drawings, and high fives.

[LISTING HONOR ROLL]

We'll be back next week with more answers to your questions.

PENELOPE AND JACK: Thanks for listening.

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