Have you ever wondered why a guitar sounds different from a violin? Or why a banjo is twangy and a cello is mellow? Then this episode is for you!

Join Molly and co-host Ellie as they explore the ear-tickling world of string sounds! Together, they’ll learn about sound waves, and visit the Brains On instrument petting zoo, where they'll learn about all the amazing sounds that stringed instruments can make. Plus, a shiny new mystery sound!

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ELLIE: You're listening to Brains On, where we're serious about being curious.

ANNOUNCER 1: Brains On is supported in part by a grant from the National Science Foundation.

MARC SANCHEZ: Hey, Marc here with Ellie.

ELLIE: Hi, everyone.

MARC SANCHEZ: Normally, it would be Molly and our wonderful co-host, Ellie, who would start the show. But Ellie just arrived at Brains On HQ, and Molly is nowhere to be found.

ELLIE: Yeah, so we're going to find her. We already searched all of her regular spots.

MARC SANCHEZ: We checked Molly's office, sandins wildflower garden, Molly's other office that she keeps specifically for snacks.

ELLIE: Hey, Marc, what about this room?

MARC SANCHEZ: Oh, that's the Brains On workshop. Maybe Molly's working on a project. Let's take a look.


MARC SANCHEZ: Holy, super sized spider webs. There are strings everywhere. All my tools are tied together. There's piano wire stretching from the ceiling to the floor, rubber bands on the chairs. Ellie, this is a little embarrassing. It's not usually like this. I like my workspaces nice and tidy.

ELLIE: Molly, are you in here.

MOLLY BLOOM: Who's that? What time is it? Oh, my gosh. I'm late to meet Ellie and towards the new bridge-- oh, Ellie, you're here with Marc. Hi. I'm so sorry. I've been doing some string theory research, and I was up all night. And I took a really long nap under Marc's work table and--

MARC SANCHEZ: String theory, like from physics?

MOLLY BLOOM: What? Physics? No, no, no. My string theory. It's the idea that you can make an instrument out of any kind of string. I'm close to a real breakthrough, but I will admit that string cheese has been a little tricky.

ELLIE: Good thing we're talking about string instruments on the show today.

MOLLY BLOOM: Yeah, pretty convenient. Let's go, Ellie. I just need to make a quick stop to grab a blueberry scone from my snack office.

MARC SANCHEZ: Wait, but all my tools are still tied together, and there's dental floss wrapped around all the cabinets. And Molly, did you eat all my string cheese?

MOLLY BLOOM: Got to go. Bye, Marc.


You're listening to Brains On from APM Studios. I'm Molly Bloom, and I'm here with my co-host, Ellie, from Toronto, Canada. So glad you're here, Ellie. Hi.

ELLIE: Me too, Molly. I think you might have some silly string in your hair.

MOLLY BLOOM: Oh, Yep. Got it. Thank you so much. So, Ellie, you sent in a great question to us. Please remind us what it was.

ELLIE: I wanted to know how stringed instruments make different sounds.

MOLLY BLOOM: Excellent question. So what made you think of this question?

ELLIE: I was playing my harp, and I noticed that some strings have more of a twangy rubber band sound, whereas some are more slightly more musical.

MOLLY BLOOM: Oh, interesting. So you play the harp?

ELLIE: Yes, I do.

MOLLY BLOOM: And you brought it with you today, right?

ELLIE: Yes, I did.

MOLLY BLOOM: So Ellie, can you play the string that you think sounds a little more rubber bandy, twangy?


And then can you play the one that you think sound more musical?


So is it that the twangy one, is that a little higher? Is that why it sounds like that, do you think?

ELLIE: I don't know. I just think it sounds more like a rubber band.

MOLLY BLOOM: OK. So can you just play a little bit of the harp for us? Just a song that you like to play?

ELLIE: Sure.


MOLLY BLOOM: That's very beautiful. So, I mean, it's a gorgeous instrument, but what made you want to play the harp?

ELLIE: My mama suggested it to me. I did some research on it, and I thought it sounded really beautiful. And I thought it would be fun to try to play. And I've really enjoyed it.

MOLLY BLOOM: How long have you been playing it for?

ELLIE: I'm pretty sure I started when I was eight.

MOLLY BLOOM: OK. And how old are you now?

ELLIE: I'm 10.

MOLLY BLOOM: OK, so it's been a couple of years. That's amazing. It sounds so good. I guess we should learn first a little bit how you get the harp to make different notes.

ELLIE: So all along the harp, there are different strings.

MOLLY BLOOM: Got you. Can you play the lowest note for me?


And can you play the highest note?


Ooh, that's a big range. Are there, like, exercises or warm-ups you do on the harp?

ELLIE: Oh, yes, there are.

MOLLY BLOOM: Could you play one of those for us?


Wow, that's very soothing. I could listen to you do that all day. But I suppose we have an episode to tape. So I guess we'll stop for the time being, but maybe later you can play me some more.


Well, to really understand how incredible the world of stringed instruments is, I think we need to start with what I like to call the Wiggle wave.

ELLIE: Ooh, is that an interpretive dance, or are we waving Hi to worms? Is it a worm dance party?

MOLLY BLOOM: That sounds fantastic. But I'm actually talking about stringed instruments making Wiggles in the air. Like I always say, moving air around is the key to sound. Let me give you an example. Let's see. OK, here's a rubber band. I'm going to stretch it out between my two-pointer fingers.

Now, Ellie, grab one side of the rubber band and give it a little pull. OK. So you heard that sound, right? When you pulled back the rubber band and let it go, it moved back and forth really, really quickly in a wiggly wave motion. Here, let's try it again.

ELLIE: Yeah, I can see the rubber band going up and down really fast when it wiggles.

MOLLY BLOOM: As it goes bonging back and forth, the band pushes against the air around it, pushing it outward in the same wiggly wave pattern. Those wiggly vibrations push more air and on and on until those sound waves get to your ear and you hear.

ELLIE: It's like the sound of the rubber band is touching my ear through the air.

MOLLY BLOOM: Yeah. And the bigger the sound waves are, the louder the sound. The smaller the waves are, the quieter the sound. That's volume.

ELLIE: OK, but what about different notes? That's not the same as how loud or quiet a sound is.

MOLLY BLOOM: Right. This note is different from this note. Even if they're the same volume, the two notes are different pitches. Pitch is whether a note sounds higher or lower. Like these notes on the cello, they're low.


Low sounds make waves that are long and far apart.


ELLIE: Whoa, that's super low. So those are some really wide waves.

MOLLY BLOOM: Higher sounds make waves that are much closer together.

ELLIE: Yeah, like these high notes on a guitar.


How about a kazoo?


MOLLY BLOOM: Technically, a kazoo doesn't have strings, but we'll allow it. Wait, that's a great idea. Where's my string theory research book? Add strings to kazoo? Fantastic.

ELLIE: So instruments make sound by creating invisible waves in the air. The volume of the sound depends on how big or small the waves are. And the pitch is how close together or far apart the waves are.

MOLLY BLOOM: Speaking of sound waves, we've got some very tricky ones coming your way. It's time for the--


ANNOUNCER 2: Mystery sound.

MOLLY BLOOM: Are you ready for the mystery sound, Ellie?


MOLLY BLOOM: Here it is.


Whoa, what was that? What do you think?

ELLIE: To me, it kind of sounds like someone's spinning a top or rolling a die on top of, like, a guitar.

MOLLY BLOOM: Ooh, I love that. I have no idea what this is either, so I am stumped. Should we hear it again?




What do you think now? Any new thoughts?

ELLIE: I think I'm going to stick to my original guess.

MOLLY BLOOM: Yeah, I think top is a great guess. I'm very impressed with whoever spun that top, though, because it lasted forever.

ELLIE: It did.

MOLLY BLOOM: That's a very good top spinner. All right. Well, we will hear it again. Get another chance to guess and hear the answer after the credits. So stick around. We love hearing from you. We love getting your questions, mystery sounds and high fives.

You're all so curious and smart. And something that we find extra super duper delightful is when you send us your artwork inspired by the show. Maybe you want to draw a picture of my snack office, or an instrument petting zoo. You can send us your drawings at brainson.org/contact. And while you're there, you can send us mystery sounds, drawings, and questions.

ELLIE: Like this one.

CREW: My question is, why do hot sauce make your nose run?

MOLLY BLOOM: You can find answers to questions like these on the Moment of Um podcast. It's a daily dose of facts and fun every weekday. You can find it wherever you listen to Brains On. Just search for Moment of. Um.

ELLIE: So keep listening.

ANNOUNCER 3: Brains On Universe is a family of podcasts for kids and their adults. And since you're a fan of Brains On, we know you'll love the other shows in our universe. Come on, let's explore.

ANNOUNCER 4: Entering Brains On Universe. Whoa, so many podcasts. Brains On, Smash Boom Best, Forever Ago. Picking up signal. Forever Ago, a history podcast starring Joy Dolo.

JOY DOLO: Fleer's gum was so sticky when the bubble popped. It was so hard to get off your skin. You'd have to scrub it off with harsh chemicals.

ANNOUNCER 4: Me love sticky facts zorp signal down quick need forever ago now

ANNOUNCER 3: Search for Forever Ago wherever you get your podcasts.

CREW: Ba ba ba ba ba ba ba ba. Brains On.

ELLIE: You're listening to Brains On. I'm Ellie.

MOLLY BLOOM: And I'm Molly. And we've been talking about how stringed instruments make sounds.

ELLIE: It starts when you pluck or strum or bow a string, which makes that string vibrate or wiggle.

MOLLY BLOOM: Those wiggles from the string, push on the air around it and make that air wiggle, too. That makes a sound wave, which travels to our ears. And speaking of sound waves, we asked all of you to make some waves by recreating the Brains On theme song.

ELLIE: Check it out.


MOLLY BLOOM: Wow many Thanks to Gavin, Cooper, Carter, Charlie, Asher, Mia, Caleb, Lucy, Eddie, Waylon, and Roxy for those incredible renditions. I am in awe of your magical music minds. So good. I still hear them in my head.

ELLIE: That's not coming from your head. It's coming from your pocket.

MOLLY BLOOM: Oh, it's my phone. And it's Brains On producer, Anna Goldfield. Hey, Anna. What's up?

ANNA GOLDFIELD(ON PHONE): Hey, Molly. Are you with Ellie?

MOLLY BLOOM: Yeah, Ellie's here with me, and we're talking about stringed instruments. Why?

ANNA GOLDFIELD(ON PHONE): I'm feeding the instruments at the petting zoo. You want to come by?

MOLLY BLOOM: Feeding time at the instrument petting zoo? Heck, Yeah. We'll be right there. Come on, Ellie.

CREW: Brains, brains, brains.

MOLLY BLOOM: Here we are.

ANNA GOLDFIELD: Hey, Molly. Hi, Ellie. I'm so glad you're here. Hang on. Just let me wash my hands. Feeding the trombones always gets so messy. That's better. Welcome to the instrument petting zoo.

ELLIE: It's just a room with lots and lots of instruments laying on the floor.

ANNA GOLDFIELD: Just instruments? These are my prized instrument herds, all free-range, well-trained, and totally pampered. And when the Herd and I heard you were going to be talking about stringed instruments, I wanted to show them off.

MOLLY BLOOM: Anna's ukulele won first prize at the fair loss year. See, it's got a blue ribbon on it.


MOLLY BLOOM: Ellie and I were just talking about how strings make sound waves in the air.

ELLIE: And how we hear the sound waves as notes. They can be higher or lower, and louder or softer. But I still want to know why instruments sound different from one another.

MOLLY BLOOM: That's a fantastic question. Another one of my string theories is that it depends on what you feed your instruments. A well-fed instrument always sounds better, right, Anna?

ANNA GOLDFIELD: Only the best diets of healthy whole notes for my little orchestra. But really, it's all about how each instrument bounces those sound waves around. Instruments have different shapes and are made of different things. All of that can change the sound they make.

ELLIE: Yeah, my harp and your guitar are really different shapes and sizes, and they make really different sounds.

ANNA GOLDFIELD: Exactly. Here, let me show you with my acoustic guitar. Come here, baby. Yeah. So an acoustic guitar usually has six strings and a hollow body made out of wood. The strings start at the top of the neck. That's where you press down to make different notes. And at the other end of the guitar, the strings are stretched over a thin piece of wood called a bridge that helps pass vibrations into the guitar. You can pluck the strings and it sounds like this. [GUITAR STING] Or you can strum them like this. [GUITAR STING]

ELLIE: And there's a hole right in the middle of the guitar underneath where you're strumming.

MOLLY BLOOM: Another one of my string theories is that strings make better sound waves if you compliment them regularly, and also if the sound waves can bounce around a lot.

ANNA GOLDFIELD: And bouncing is exactly what's happening. When I play the strings, they vibrate throughout the guitar and through this round hole in the middle called the sound hole.

ELLIE: And then they keep bouncing off the walls inside the guitar?

ANNA GOLDFIELD: Yeah, it's kind of like when you yell into a tunnel, you know. I love to yell. Your voice makes sound waves that bounce around the tunnel and you hear the echoes all coming back on top of each other.

ELLIE: So the inside of the guitar is like the inside of a tunnel, bouncing sound waves around?

ANNA GOLDFIELD: Yes, and the sound waves come back out of the sound hole, making a bigger, rounder, and fuller sound than just the strings twanging on their own. The shape of an instrument and the stuff it's made from can totally change how those strings sound.


ANNA GOLDFIELD: I'll show you. How about we play a little guessing game? I'll play three of my beautiful instrument buddies for you. You can try to figure out which instruments are making the sounds, and then I'll tell you how their shape and how they're made influences the sound. Molly and Ellie, are you ready. Yeah.

ELLIE: Yeah.

ANNA GOLDFIELD: OK. Here's instrument number one.


MOLLY BLOOM: That was fun. What do you think, Ellie?

ELLIE: I think that was the sound of maybe a banjo?

MOLLY BLOOM: Ooh, yeah. It kind of had that sound like someone strumming strings. Kind of like a guitar. It sounded like between a guitar and a banjo.

ELLIE: But not really a ukulele.

MOLLY BLOOM: Yeah, I agree. OK.

ELLIE: More of a country sound.

MOLLY BLOOM: More of a country sound. I'm going to go with a tiny guitar, that's not a ukulele. Why are we right?

ANNA GOLDFIELD: So you were right on the money with your thought that maybe it was kind of country, because this instrument is used in country and Bluegrass music a lot. That was a mandolin.

MOLLY BLOOM: What's a mandolin, Anna?

ELLIE: I've never heard of it before.

ANNA GOLDFIELD: Well, a mandolin is an instrument that's around the same size as a violin. So you can hold it pretty easily in one hand, and the body of it is kind of a teardrop shape. And it's got. four notes like a violin. It's tuned like a violin. But each note is played by two strings. So there are pairs of strings. And it gives it that kind of full sound, that nice round sound that you heard. But it makes it really tricky to tune. All right.

MOLLY BLOOM: Will you please show us instrument number two?


Wow, that was deep. What do you think, Ellie?

ELLIE: It sounded kind of like maybe, like a cello.

MOLLY BLOOM: Ooh, good guess. I think it sounds even deeper than a cello. Is it a bass? What is it called? Is it a bass? Like the one that stands upright? Like a really big cello?

ANNA GOLDFIELD: Yeah, you nailed it. It is an upright bass. So those are some big, big, wide sound waves because the notes were so low. So I want you to picture a violin with that kind of figure eight shape, and the F-shaped holes in the body, and then the neck and the tuning pegs. And then I want you to imagine that that violin is six feet tall, because that's how big a string bass is.


ELLIE: That's very tall for an instrument.

ANNA GOLDFIELD: All right. Are you ready for instrument number three?




What do you think, Ellie?

ELLIE: I hear guitar sounds. But then again, I also hear, like, high pitched buzzing like a trumpet. But then I also hear metal clicking, so I don't really know.

ANNA GOLDFIELD: Yeah, those are really good observations.

MOLLY BLOOM: I think I have an idea of what it is.


MOLLY BLOOM: Is this an instrument from India? It is-- tell us what it is.

ANNA GOLDFIELD: That was the sound of a sitar. The sitar is a plucked string instrument. It's related to a lute, and it's about four feet long, And you play it sitting down with the body in your lap. The body is kind of a pear-shaped gourd, and it's got a long, wide neck that you kind of hold up at an angle and play.

And sitars can have between 18 and 21 strings. And that's because some of the strings are for plucking, and some lined up underneath the plucked strings are sympathetic. That doesn't mean they'll sit and listen to your problems. Sympathetic vibration is when a sound or other type of wave passes from one object to another.

So when the sitar player plucks the top strings that are stretched over these high, curved wooden bridges that hold them up off the body of the instrument, the sound waves also travel to the strings underneath, and those vibrate a little bit. And that makes that twangy, echoey sound that you heard.

MOLLY BLOOM: That's so cool.

ELLIE: That's amazing.

MOLLY BLOOM: Yeah, sitar is fun.

ANNA GOLDFIELD: Thank you both so much for playing with me.

ELLIE: Thank you, Anna.

MOLLY BLOOM: That was so fun. And I think this proves my biggest string theory of all-- stringed instruments are wonderful because they make so many amazing sounds. What a breakthrough? Maybe now I can finally make the string cheese harp I've been dreaming of. Where's my notebook?


ELLIE: Stringed instruments push air into wiggly sound waves, which travel to our ears.

MOLLY BLOOM: Loud sound waves are made up of big wiggly waves and soft sounds are made up of smaller, wiggly waves.

ELLIE: The pitch of a sound is how high or low it is.

MOLLY BLOOM: And stringed instruments sound different from each other because of the different tools used to hit, pluck, or play them.

ELLIE: Plus the size and shape of their bodies.

MOLLY BLOOM: That's it for this episode of Brains On.

ELLIE: This episode was written by Anna Goldfield. It was produced by Molly Bloom and Rosie Dupont. Our editors are San Anton and Shahla Farzan. Fact checking by Ruby Guthrie.

MOLLY BLOOM: We had engineering help from Gary O'Keefe, Derek Ramirez, Lucien Lozon, and Bill Walker with sound design by Rachel Breeze. Original theme music by Marc Sanchez.

We had production help from the rest of the Brains On Universe team-- Anna Goldfield, Nico Gonzalez Wisler, Lauren Humpert, Joshua Ray, Charlotte Traver, Anna Weggel, and Aron Woldeslassie. Beth Perlman is our executive producer and the executives in charge of APM Studios are Chandra Kavati and Joanne Griffith. Special thanks to Jonathan and Diane Scarlet.

ELLIE: Brains On is a non-profit public radio program.

MOLLY BLOOM: There are lots of ways to support the show. Subscribe to Brains On Universe on YouTube, where you can watch animated versions of some of your favorite episodes or head to brainson.org.

ELLIE: While you're there, you can send us mystery sounds, drawings, and questions.

MOLLY BLOOM: Speaking of mystery sounds, Ellie, are you ready to hear that sound again?

ELLIE: Yeah.



Nice. OK. What do we think?

ELLIE: I'm still sticking to my original guess-- the die or the top rolling or spinning on top of a guitar, or a table.

MOLLY BLOOM: I love that guess. I have no idea. So I'm going to stick to your guess too. Let's hear the answer.

EDGAR: Hi, my name is Edgar from Acworth, Georgia. And that was the sound of my top spinning.

MOLLY BLOOM: Oh, my gosh, Ellie. You did it. You got it right. How does that feel?

ELLIE: Great.

MOLLY BLOOM: Awesome. Have you spun tops before? You must have.

ELLIE: Yes, I have.

MOLLY BLOOM: Can you spin your tops, as long as Edgar can? Because that was pretty impressive, Edgar.

ELLIE: No, the tables in my house have, like, cracks on them for the wood as a design. So they always get stuck on them.

MOLLY BLOOM: OK, we need a better surface for you. Wow. Good guessing. Excellent ears.


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



We'll be back next week with an episode all about vacuums.

ELLIE: Thanks for listening.

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