The keyboard of a Concert Grand Model D piano is pictured in the final inspection room at the Steinway & Sons factory.
TIMOTHY A. CLARY/AFP/Getty Images
Behind every piano’s polished exterior are thousands of parts. From keys to strings, they work together to produce a sound. In this episode, we take a field trip to a piano shop, peek behind the walls at a world-famous piano factory and have an EPIC FIGHTING BATTLE to discover how sound travels.
Hammers and keys on display as a piano is assembled at the Steinway & Sons piano factory in New York. Christopher Payne
When you press a key, a felt-covered hammer inside the piano strikes metal strings. It is the vibration of these metal strings that make that familiar piano sound. But the most complicated part is the action, a Rube Goldberg-looking series of parts and levers that work together to make the hammer strike the strings.
This episode was originally published on April 11, 2017. You can listen to that version here:
How do pianos pianos work?
by MPRAudio Transcript
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[PIANO MUSIC] MOLLY BLOOM: You're listening to Brains On from American Public Media-- we're serious about being curious. I'm Molly Bloom, and today's episode is all about the sound you're hearing behind my voice-- the piano. We started thinking about pianos thanks to a question that came in from Sela.
SELA: I'm eight years old and I live in Quincy, Massachusetts. My question is, how does a piano make sound? I ask this question because I'm learning how to play the piano.
MOLLY BLOOM: That's awesome, Sela. I started taking piano lessons in third grade, and many years later, playing piano is still one of my favorite things to do. I think you're going to be happy if you stick with it. Brains On Producer Mark Sanchez joined me on a hunt for the answer to your question.
MARC SANCHEZ: Hey, Molly.
MOLLY BLOOM: Hi, Marc.
MARC SANCHEZ: In order to understand how pianos work, first, we have to think about all the parts of a piano. If you've ever seen a piano, you know the black keys and the white keys, but there's so much more going on behind each key that we never even think about. Every time we press down on one, it sends hundreds and hundreds of moving parts into action.
MOLLY BLOOM: Yeah. And actually, that word, action, plays a big part in how pianos make sound. Inside each piano, is a series of levers called the action.
MARC SANCHEZ: There's also a series of metal strings, kind of like you'd see on a guitar, or maybe a harp.
MOLLY BLOOM: The sound we hear from a piano is actually those strings being hit.
[PIANO MUSIC]
MARC SANCHEZ: Molly and I dropped by Keys 4/4 Kids. They sell used pianos, here in St. Paul. When we got there, it was so cool. There were pianos of all different shapes and sizes, everywhere you looked in that shop.
MOLLY BLOOM: And there are another two huge backrooms, also filled with pianos.
MARC SANCHEZ: The people there are constantly moving, fixing up, and playing these instruments.
MOLLY BLOOM: At the center of the action are Carmen Mancino and Carl Schmidt. They work in the store, surrounded by these pianos all day. I asked Carmen to answer Sela's question. How does a piano make sound?
CARMEN MANCINO: If you imagine your leg. There are many pieces of your leg that have to move in order to make you walk. So you have your hip, and your thigh, and your knee, and your calf, and then your ankle, your heel, your foot, and your toe. If your toe is the hammer that would strike the string, that's how the piano action moves. Everything has to move in accordance with each other to get you to actually walk, just like everything has to move in accordance with each other to get the note to play.
[PIANO MUSIC]
CARL SCHMIDT: Everybody knows what a piano keyboard looks like. There's white keys. There's black keys. What happens when you push down on one of those keys?
CARMEN MANCINO: Yeah. The key is balancing on a pin in the bed where the keys are. And then when you push down on the edge that you're playing keys on, the other end of the key, toward the back of the piano, lifts up, and--
CARL SCHMIDT: This is something that you can't see, right?
CARMEN MANCINO: Yeah, yeah. So it lifts up inside the piano cabinet-- inside the piano's, like, house-- and then that, in turn, lifts a few other mechanisms. They're made mostly out of wood, springs, and felt, for the most part. And then from there, it's kind of like that game Mousetrap, where you flip one thing, and then another thing flips, then another thing flips. And it looks like that inside.
And that's what I was talking about, with your leg movement. So all these different parts then move to strike the strings. And the strings are held together inside the piano. The ends of them are coiled around tuning pins, which are metal, and they're shoved into a wood pin block to help keep them really tight.
[PIANO MUSIC]
So what's actually making the sound?
CARL SCHMIDT: Yeah. Sound is produced by vibrations which are caused, in this case, by the hammer hitting-- striking-- the strings. And so the sound waves vibrations are resonating off the soundboard of the piano.
MOLLY BLOOM: By the way, a soundboard is a large, flat piece of wood set behind the strings of every piano. It helps amplify the sounds coming from the instrument. Then there are the hammers
CARL SCHMIDT: [LAUGHS] The felt-- the hammer felt in the piano.
CARMEN MANCINO: It's like a popsicle stick with a cotton ball wrapped around it-- wrapped around the end of it. And then if you were just using the very tip of it with the cotton ball piece of it to hit a string, so it's really soft.
MOLLY BLOOM: And then are there-- is there one hammer or lots of hammers? How does that work?
CARL SCHMIDT: So the strings are, kind of, zigzag, I guess you could say. And per hammer generally hits three strings.
CARMEN MANCINO: And that's-- when you're tuning a piano, you're tuning all of those strings to sound the same to each other. And it helps give it that volume. It helps give it that special tone.
MOLLY BLOOM: All playing the same note?
CARMEN MANCINO: Mm-hmm, mm-hmm.
MOLLY BLOOM: Got it. And so then, each note has its own hammer.
CARMEN MANCINO: Mm-hmm.
MOLLY BLOOM: So if you're playing a chord that has three notes in it, there's three hammers that are hitting sets of strings.
CARMEN MANCINO: Yes, so nine strings. And you can open up a piano. That's what our technicians do when they work on the pianos, is they lift off like the front board of it. They lift off the fall board, which is the part that covers the keys, so that the piano is just open and waiting to be worked on.
MOLLY BLOOM: If you ever see a grand piano, those are open and you can kind of see all these things happening, right?
CARL SCHMIDT: Yeah, it's really neat to watch everything move around. It's kind of crazy.
[PIANO MUSIC]
NARRATOR: (SINGING) Brains On. [CLEARS THROAT]
MOLLY BLOOM: OK, Carmen and Carl have taken us on a mini-journey from piano keys to strings, but we have to take a timeout here to talk about sound itself.
DENA: Hi, my name is Dena from, White Bear Lake, Minnesota. How do things make sounds and be how soft they are and how loud they are?
OAKLEY: Hi, my name is Oakley. I'm from Nashville and I want to know how sounds and vibrations work.
MOLLY BLOOM: In a piano, when the hammer hits the strings, the strings vibrate, and it's vibrations that are responsible for every sound we hear. Vibrations create sound waves. For more on how those work, let's head out to a very special arena.
[MUSIC PLAYING]
Welcome to Most Epic Fighting Battle Realm. Choose your warrior. Monster Master, you go first.
MONSTER MASTER: I choose Gungador, Slayer of Things, Stomper of Other Things. He cannot be defeated!
[CHIME]
GUNGADOR: Gungador smash!
MOLLY BLOOM: What a worthy warrior. Now, it's your turn to choose, Allie.
ALLIE: I choose a soundwave.
MOLLY BLOOM: Sound wave? What's that? Oh, you must mean Wavenado!
[MUSIC PLAYING]
MONSTER MASTER: His mists hit like gale-force winds.
ALLIE: No, I mean a sound wave. You know, like how sound travels? That's how you're hearing me right now.
GUNGADOR: Gungador confused.
MONSTER MASTER: Yeah, I thought the waves come from water, like in the ocean, where She-Man-She lives.
MOLLY BLOOM: Yes, she is a worthy warrior. Why not choose her?
ALLIE: Well, water waves are one type of wave, but there are lots of them. These waves are just disturbances of energy that travel through something from one place to another. We call that something a medium. For ocean waves, the medium is water. For sound waves, the medium is usually air.
MONSTER MASTER: Oh, so it is an air attack. Gungador will withstand the blows!
GUNGADOR: Gungador strong!
ALLIE: Well, kind of. See, a sound wave works like this. When I talk, air from my lungs goes through my throat and vibrates my vocal cords.
[WOBBLING ELECTRONIC SOUND]
As those cords vibrate, it also vibrates the air directly around them. Then, those vibrating air molecules bump into other molecules next to them, which makes those molecules vibrate, too. Then they bump into other molecules, and on, and on, and on, until some vibrating molecules bump into your eardrums. That causes them to vibrate.
GUNGADOR: Gungador has drum in ear?
ALLIE: Your brain senses those eardrum vibrations and translates them to a message, like my voice.
MONSTER MASTER: Wait, so sound waves shoot air molecules at us? That's a clever attack, I guess.
ALLIE: Not quite, Monster Master. The individual molecules don't actually travel. They just wiggle in place. Think of it this way. If there's a tightly packed crowd of monsters, and one monster in the front bumps the monsters next to them--
WOMAN: Excuse me.
ALLIE: --those monsters will then stumble.
MAN: Whoa, sorry.
ALLIE: When they do that, they'll bump into more monsters--
WOMAN: Oof, watch it.
ALLIE: --who will then stumble into others--
WOMAN: Ow.
MAN: Coming through.
ALLIE: --and on, and on, and on, through the crowd. Even though each monster stays where they started, the energy disturbance travels through the whole crowd.
WOMAN: Sorry about that.
ALLIE: That's how it is with sound. When I clap--
[CLAPS]
--the energy disturbance travels from my hand to your ear, even if the air molecules between us are just vibrating in place. Got it?
GUNGADOR: Gungador gets it.
[CHIME]
MONSTER MASTER: I don't need to get it to know your sound wave is no match for mighty Gungador, Chomper of Trees, Stomper of Large Bushes. Let's battle!
MOLLY BLOOM: Let this most epic fighting battle room fighting begin.
[BELL RINGING]
MONSTER MASTER: [LAUGHS] Now you will perish. Gungador attacks with Severing Smite.
GUNGADOR: [GROWLS]
MOLLY BLOOM: Epic move that does zero damage?
MONSTER MASTER: Wait, what?
ALLIE: Yeah, sound waves are just energy disturbances passing through air, so you can't really hurt them.
GUNGADOR: Sound waves are vibrating air molecules!
ALLIE: Exactly. Nice recall, Gungador.
GUNGADOR: Gungador gets it again!
[CHIME]
Is Gungador genius?
MOLLY BLOOM: Allie, your turn to attack.
ALLIE: I'm going to play a tone and increase the pitch.
MONSTER MASTER: What is this pitch you speak of? Is it a laser, or a punch, or a laser punch?
ALLIE: Pitch is the word we use to describe how high or low something sounds. Remember how I told you air molecules wiggle in a soundwave?
GUNGADOR: Gungador remembers!
ALLIE: Well, the pitch comes from how many wiggles, or vibrations, each molecule makes over a certain amount of time. This idea is also called frequency because it has to do with how frequent the vibrations are. If those air molecules wiggle slowly, and they vibrate only a couple dozen times a second, then the pitch sounds low, like this.
[STEADY TONE]
But if they vibrate quickly, hundreds of times a second, then the pitch sounds high, like this.
[RISING TONE]
MONSTER MASTER: Ah, the noise is horrible.
MOLLY BLOOM: But it also does zero damage. Monster Master, your turn.
MONSTER MASTER: Gungador attacks with Beast Blast!
GUNGADOR: [GROWLS]
MOLLY BLOOM: And that does--
[BUZZER]
--also zero damage.
MONSTER MASTER: What?
ALLIE: Sorry. Remember how sound waves aren't hurt by punches or swipes?
MONSTER MASTER: Oh, yeah. [MUTTERING]
MOLLY BLOOM: [SIGHS] All right, this battle is so not epic. Very well, Allie, go again.
ALLIE: I'm going to take that tone I made this last round and increase the amplitude.
MONSTER MASTER: Amplitude, is that like attitude?
GUNGADOR: Gungador's attitude is biggest in land!
MONSTER MASTER: I don't think that means what you think it means, Gungador.
ALLIE: Actually, amplitude is related to volume or loudness. It means how much energy the sound wave is carrying. When you increase the energy, to us it sounds like the tone is getting louder. So if I take this tone
[STEADY TONE]
--and dial up the amplitude--
[TONE INCREASES IN VOLUME]
--it gets loud!
GUNGADOR: Can't hear own self thinking. Gungador too messed up to fight!
[ELECTRONIC WARBLING]
MOLLY BLOOM: Gungador loses a turn.
MONSTER MASTER: No fair.
MOLLY BLOOM: Back to you, Allie.
ALLIE: I'm going to use my soundwave to play music.
[MUSIC PLAYING]
Music is a combination of different frequencies and amplitudes, as well as things like tone and rhythm. Still, it's all just sound waves that are traveling through the air.
GUNGADOR: Gungador feels urge to-- dance? Gungador must bust a move. Hoo, ha. Hoo, ha.
MONSTER MASTER: Stop flailing about a fool and get ready for your next attack, Gungador.
GUNGADOR: No. Gungador found new calling in life. Gungador is genius who likes dancing-- no more battles!
MOLLY BLOOM: And that settles it-- Allie and the sound waves win.
ALLIE: Sweet. Woo-hoo!
MONSTER MASTER: No!
MOLLY BLOOM: That's it for this really weird edition of Most Epic Fighting Battle Realm. Game over.
GUNGADOR: Hoo, ha. Hoo, ha.
MOLLY BLOOM: We love getting your drawings. And you know what we'd love to see? Your drawings of Gungador fighting a soundwave. We think that would be epic, indeed. Send them to hello@brainson.org.
We're going to tickle the ivories a little more in a minute. But first, let's tickle your eardrums. It's time for the mystery sound.
[MUSIC PLAYING]
NARRATOR: Mystery sound.
MOLLY BLOOM: Here it is.
[SCRATCHING]
Stick around. We'll be back with the answer, a little later in the show.
[PIANO MUSIC]
Do you have a question for the show, or do you want to send us a mystery sound or a drawing? You can send them to us at brainson.org/contact. And if you're into actual mail-- the kind with paper, and stamps, and envelopes-- head to brainson.org. You'll find our physical mailing address on the Contact Us page. To thank the awesome kids who contribute their ideas and energy to the show, we add their names to the Brains Honor Roll, like Felix, from New Jersey. He has a theory about the sound in seashells.
FELIX: I would like to know how you hear the ocean in a shell? So basically, it's probably just the air rushing around inside the shell. So when you do hear the shell, well then it's not really the ocean-- it's just the air that you hear in the shell.
MOLLY BLOOM: Well, Felix, that does sound interesting. We'll have an answer to that question in our Moment of Um. Listen for that, and the latest installment of the Brains Honor Roll, at the very end of this episode.
You're listening to Brains On. I'm Molly Bloom. And today, we're talking--
[PIANO MUSIC]
--pianos.
[PIANO MUSIC]
ANDREW: There are black keys and white keys, and they all have different sounds.
SHAWN: In the bottom, it looks like sticks, and on the top it looks like marshmallows.
BRIELLE: I'm pretty sure there are, like, strings, maybe, that, like, when you press the key, then it vibrates and it makes a sound, I guess.
MARIBEL: Yeah, I think that's how it works.
ANDREW: Those sounds, like a deep voice, and it can make a high pitched voice, too.
BRIELLE: When I'm playing, like, something happy, I hit it harder than I would play with something sad.
MARIBEL: When you play something that's said, it's slower. And when you play something that's happier, you play it with, like, more pizzazz and a lot, like, quicker.
MOLLY BLOOM: That was Brielle, Maribel, Andrew, and Shawn. They're all students at Walker West Music Academy, in St. Paul.
[PIANO MUSIC]
You hear how that piano note is still going? It sounds like it's never going to stop. That's because of the sustain pedal. Most people think about fingers playing a piano, but there's a lot going on below the keys, too. Every piano has a set of pedals that you use your feet to push. Six-year-old Theo, from Woodbury, Minnesota, has this question.
THEO: Why do pianos have three pedals? Because I play piano a lot and I want 20.
MOLLY BLOOM: Hmm, 20? Oof, that is too many for my brain to think about, or I'd at least need a few more feet to handle them. Until you invent your 20-pedaled piano, most pianos are stuck with three. Push on the sustain pedal while you play a note, and the note rings out, even after your finger is off the key.
[PIANO MUSIC]
But what do the other pedals do? Let's go back to the Piano Shop, to get an answer from Carmen and Carl.
CARL SCHMIDT: Yeah. Generally on upright pianos, there is a soft pedal which moves the hammers closer to the strings, and it just kind of produces a softer tone.
CARMEN MANCINO: Pianos have different pedals, and they might not all be the same pedal on every piano. There's usually a soft pedal, which is the one, like Carl said--
CARL SCHMIDT: On the left, yeah.
CARMEN MANCINO: Yep, it's the one on the left, that moves the hammers just a little bit forward to make a softer sound in tone. And then another kind of pedal is a sostenuto, which is like the sustain pedal. On the sustain pedal, the sound keeps ringing, no matter which keys you're playing. But on a sostenuto pedal, the sound only keeps ringing on the first chord that you're playing. And then you can play other notes, and it creates a staccato effect when you're playing the other notes, while the first chord continues to ring.
MOLLY BLOOM: That's cool.
MARC SANCHEZ: Wow, I like that.
CARMEN MANCINO: What other kind of pedals are there?
CARL SCHMIDT: There's a pedal that basically drops a sheet of felt in front of the hammers-- in between the hammers and the strings. And that is considered a silent pedal.
MARC SANCHEZ: So if you wanted to play, maybe, really quietly at night and not wake up the neighbors.
CARL SCHMIDT: Yeah, that'd be the one to use.
MOLLY BLOOM: Thanks to Carl and Carmen for that pedal explanation. OK, let's go back to that mystery sound. Wanna hear it one more time? Here it is.
[SCRATCHING]
Any guesses? Did you change your mind after you heard it a second time? Well, here with the answer is Mathis, from Piedmont, California.
MATHIS: That was the sound of me, running my thumbnail against the sixth string of my guitar.
MOLLY BLOOM: So you might be picturing just a regular old string. Well, it's not. It's actually a tightly wound coil of metal. And those strings are similar to the strings that make the lower notes on a piano.
[MUSIC PLAYING] Ba, ba, ba, ba, ba, ba, ba, ba, ba, ba, ba, Brains On.
MOLLY BLOOM: Now we know about the pedals, and we know about the keys, and we know a bit about the action. But there are thousands and thousands of parts inside a piano that all work together. There are so many parts that you'd really need to work in a piano factory to know about all of them.
BOB BERGER: My name is Bob Berger. I work at Steinway and Sons as Director of Customer Satisfaction. I grew up here in New York City. I grew up in Astoria, which is where the Steinway factory is located. I was hired here as an engineer many years ago-- almost 30 years ago. I know the pianos pretty well.
MOLLY BLOOM: Since Bob knows pianos inside and out, we decided to play a little game with him. We gave him 30 seconds to name as many parts as he could. Time starts now.
BOB BERGER: Pedals, lyre box, lyre pillars-- hammer, hammer shank, knuckle, repetition, fly, jack, let-off screw, treble wire, bass wire, grand piano plate, soundboard, bridge, front rail, keybend, keybend endcaps, keyboard, sharps, naturals, cap stands, action hangers.
[BUZZER]
MOLLY BLOOM: Wow, that was amazing. Some of those parts sounded familiar, but others I had never heard of before. Putting a piano together is a feat of engineering, but let's not forget the builders and the musicians who are also involved.
BOB BERGER: You need expertise in wood technology, and finishing, and adhesives, and metallurgy, and acoustics. The piano, and certainly the Steinway piano, is probably the most highly-engineered acoustic instrument that exists. And that's because of the force of the strings on the case is incredible.
It will range from anywhere from 20,000 to 35,000 pounds of force. And this type of force needs to be controlled. And you need to have a structure that's very stable, that will not move under that tremendous force. And it's made out of wood and metal. And it's a very challenging, interesting product to make.
[PIANO MUSIC]
MOLLY BLOOM: Pianos are complicated machines that make beautiful sounds, by striking a key, which triggers the action, and that hammers a string, and that string vibrates to make a sound. Sound is made up of vibrations moving through the air and that's what we hear. Who could forget sound waves? Right Gungador?
GUNGADOR: Sound waves are vibrating air molecules! Gungador gets it again!
[CHIME]
MOLLY BLOOM: Thanks to Nancy Yang, Allie Hinsey Francis, and John Miller. We had engineering help this week from Michael Demark and Veronica Rodriguez. Special thanks to Keys 4/4 Kids for hosting us. Part of every piano sale there goes towards putting another piano in someone else's home-- Very cool. And now for the Moment of Um.
ALL: Um, um, um, um, um, um, um, um, um, um, um, um, um, um, um, um, um, um,
MOLLY BLOOM: Remember, Felix had a question about why people say you can hear the ocean in a seashell. He had a theory, too.
FELIX: When do you hear the shell, it's probably just the air rushing around in the shell.
MOLLY BLOOM: So is Felix right?
STEVE ERREDE: He's correct.
MOLLY BLOOM: That's Steve Errede. He's a Professor of Physics at the University of Illinois. He's here to tell us more about how seashells trick us into hearing the ocean.
STEVE ERREDE: If you have any arbitrarily shaped container-- for example a pop bottle-- there will be resonances of sound at certain frequencies, because of the shape of that container. And the shape of the container actually dictates what those resonant frequencies are so. If you blow across the mouth of a pop bottle, you will hear a pitch.
[BLOWING SOUND]
So if you have a shell, the shell has a different shape from a pop bottle, obviously. That shape dictates what kinds of resonances, at certain frequencies, it will have. The air is actually oscillating in and out of the shell. When you turn it from side to side, you can hear different resonant frequencies. And that's sort of reminiscent of the sound of waves crashing on the beach at an ocean, so people say you can hear the ocean in a seashell
[BLOWING SOUND]
ALL: Um, um, um.
MOLLY BLOOM: OK, it's time for the Brains Honor Roll. If you've recently sent us an email with a question, or mystery sound, or drawing, please be patient. The list is growing but the wait is worth it. Here's a podcast high-five to all our listeners who keep this show going with their energy and ideas.
[MUSIC PLAYING]
[LISTING HONOR ROLL]
[MUSIC PLAYING] (SINGING) Brains are all alive.
MOLLY BLOOM: Thanks for listening.
SELA: I'm eight years old and I live in Quincy, Massachusetts. My question is, how does a piano make sound? I ask this question because I'm learning how to play the piano.
MOLLY BLOOM: That's awesome, Sela. I started taking piano lessons in third grade, and many years later, playing piano is still one of my favorite things to do. I think you're going to be happy if you stick with it. Brains On Producer Mark Sanchez joined me on a hunt for the answer to your question.
MARC SANCHEZ: Hey, Molly.
MOLLY BLOOM: Hi, Marc.
MARC SANCHEZ: In order to understand how pianos work, first, we have to think about all the parts of a piano. If you've ever seen a piano, you know the black keys and the white keys, but there's so much more going on behind each key that we never even think about. Every time we press down on one, it sends hundreds and hundreds of moving parts into action.
MOLLY BLOOM: Yeah. And actually, that word, action, plays a big part in how pianos make sound. Inside each piano, is a series of levers called the action.
MARC SANCHEZ: There's also a series of metal strings, kind of like you'd see on a guitar, or maybe a harp.
MOLLY BLOOM: The sound we hear from a piano is actually those strings being hit.
[PIANO MUSIC]
MARC SANCHEZ: Molly and I dropped by Keys 4/4 Kids. They sell used pianos, here in St. Paul. When we got there, it was so cool. There were pianos of all different shapes and sizes, everywhere you looked in that shop.
MOLLY BLOOM: And there are another two huge backrooms, also filled with pianos.
MARC SANCHEZ: The people there are constantly moving, fixing up, and playing these instruments.
MOLLY BLOOM: At the center of the action are Carmen Mancino and Carl Schmidt. They work in the store, surrounded by these pianos all day. I asked Carmen to answer Sela's question. How does a piano make sound?
CARMEN MANCINO: If you imagine your leg. There are many pieces of your leg that have to move in order to make you walk. So you have your hip, and your thigh, and your knee, and your calf, and then your ankle, your heel, your foot, and your toe. If your toe is the hammer that would strike the string, that's how the piano action moves. Everything has to move in accordance with each other to get you to actually walk, just like everything has to move in accordance with each other to get the note to play.
[PIANO MUSIC]
CARL SCHMIDT: Everybody knows what a piano keyboard looks like. There's white keys. There's black keys. What happens when you push down on one of those keys?
CARMEN MANCINO: Yeah. The key is balancing on a pin in the bed where the keys are. And then when you push down on the edge that you're playing keys on, the other end of the key, toward the back of the piano, lifts up, and--
CARL SCHMIDT: This is something that you can't see, right?
CARMEN MANCINO: Yeah, yeah. So it lifts up inside the piano cabinet-- inside the piano's, like, house-- and then that, in turn, lifts a few other mechanisms. They're made mostly out of wood, springs, and felt, for the most part. And then from there, it's kind of like that game Mousetrap, where you flip one thing, and then another thing flips, then another thing flips. And it looks like that inside.
And that's what I was talking about, with your leg movement. So all these different parts then move to strike the strings. And the strings are held together inside the piano. The ends of them are coiled around tuning pins, which are metal, and they're shoved into a wood pin block to help keep them really tight.
[PIANO MUSIC]
So what's actually making the sound?
CARL SCHMIDT: Yeah. Sound is produced by vibrations which are caused, in this case, by the hammer hitting-- striking-- the strings. And so the sound waves vibrations are resonating off the soundboard of the piano.
MOLLY BLOOM: By the way, a soundboard is a large, flat piece of wood set behind the strings of every piano. It helps amplify the sounds coming from the instrument. Then there are the hammers
CARL SCHMIDT: [LAUGHS] The felt-- the hammer felt in the piano.
CARMEN MANCINO: It's like a popsicle stick with a cotton ball wrapped around it-- wrapped around the end of it. And then if you were just using the very tip of it with the cotton ball piece of it to hit a string, so it's really soft.
MOLLY BLOOM: And then are there-- is there one hammer or lots of hammers? How does that work?
CARL SCHMIDT: So the strings are, kind of, zigzag, I guess you could say. And per hammer generally hits three strings.
CARMEN MANCINO: And that's-- when you're tuning a piano, you're tuning all of those strings to sound the same to each other. And it helps give it that volume. It helps give it that special tone.
MOLLY BLOOM: All playing the same note?
CARMEN MANCINO: Mm-hmm, mm-hmm.
MOLLY BLOOM: Got it. And so then, each note has its own hammer.
CARMEN MANCINO: Mm-hmm.
MOLLY BLOOM: So if you're playing a chord that has three notes in it, there's three hammers that are hitting sets of strings.
CARMEN MANCINO: Yes, so nine strings. And you can open up a piano. That's what our technicians do when they work on the pianos, is they lift off like the front board of it. They lift off the fall board, which is the part that covers the keys, so that the piano is just open and waiting to be worked on.
MOLLY BLOOM: If you ever see a grand piano, those are open and you can kind of see all these things happening, right?
CARL SCHMIDT: Yeah, it's really neat to watch everything move around. It's kind of crazy.
[PIANO MUSIC]
NARRATOR: (SINGING) Brains On. [CLEARS THROAT]
MOLLY BLOOM: OK, Carmen and Carl have taken us on a mini-journey from piano keys to strings, but we have to take a timeout here to talk about sound itself.
DENA: Hi, my name is Dena from, White Bear Lake, Minnesota. How do things make sounds and be how soft they are and how loud they are?
OAKLEY: Hi, my name is Oakley. I'm from Nashville and I want to know how sounds and vibrations work.
MOLLY BLOOM: In a piano, when the hammer hits the strings, the strings vibrate, and it's vibrations that are responsible for every sound we hear. Vibrations create sound waves. For more on how those work, let's head out to a very special arena.
[MUSIC PLAYING]
Welcome to Most Epic Fighting Battle Realm. Choose your warrior. Monster Master, you go first.
MONSTER MASTER: I choose Gungador, Slayer of Things, Stomper of Other Things. He cannot be defeated!
[CHIME]
GUNGADOR: Gungador smash!
MOLLY BLOOM: What a worthy warrior. Now, it's your turn to choose, Allie.
ALLIE: I choose a soundwave.
MOLLY BLOOM: Sound wave? What's that? Oh, you must mean Wavenado!
[MUSIC PLAYING]
MONSTER MASTER: His mists hit like gale-force winds.
ALLIE: No, I mean a sound wave. You know, like how sound travels? That's how you're hearing me right now.
GUNGADOR: Gungador confused.
MONSTER MASTER: Yeah, I thought the waves come from water, like in the ocean, where She-Man-She lives.
MOLLY BLOOM: Yes, she is a worthy warrior. Why not choose her?
ALLIE: Well, water waves are one type of wave, but there are lots of them. These waves are just disturbances of energy that travel through something from one place to another. We call that something a medium. For ocean waves, the medium is water. For sound waves, the medium is usually air.
MONSTER MASTER: Oh, so it is an air attack. Gungador will withstand the blows!
GUNGADOR: Gungador strong!
ALLIE: Well, kind of. See, a sound wave works like this. When I talk, air from my lungs goes through my throat and vibrates my vocal cords.
[WOBBLING ELECTRONIC SOUND]
As those cords vibrate, it also vibrates the air directly around them. Then, those vibrating air molecules bump into other molecules next to them, which makes those molecules vibrate, too. Then they bump into other molecules, and on, and on, and on, until some vibrating molecules bump into your eardrums. That causes them to vibrate.
GUNGADOR: Gungador has drum in ear?
ALLIE: Your brain senses those eardrum vibrations and translates them to a message, like my voice.
MONSTER MASTER: Wait, so sound waves shoot air molecules at us? That's a clever attack, I guess.
ALLIE: Not quite, Monster Master. The individual molecules don't actually travel. They just wiggle in place. Think of it this way. If there's a tightly packed crowd of monsters, and one monster in the front bumps the monsters next to them--
WOMAN: Excuse me.
ALLIE: --those monsters will then stumble.
MAN: Whoa, sorry.
ALLIE: When they do that, they'll bump into more monsters--
WOMAN: Oof, watch it.
ALLIE: --who will then stumble into others--
WOMAN: Ow.
MAN: Coming through.
ALLIE: --and on, and on, and on, through the crowd. Even though each monster stays where they started, the energy disturbance travels through the whole crowd.
WOMAN: Sorry about that.
ALLIE: That's how it is with sound. When I clap--
[CLAPS]
--the energy disturbance travels from my hand to your ear, even if the air molecules between us are just vibrating in place. Got it?
GUNGADOR: Gungador gets it.
[CHIME]
MONSTER MASTER: I don't need to get it to know your sound wave is no match for mighty Gungador, Chomper of Trees, Stomper of Large Bushes. Let's battle!
MOLLY BLOOM: Let this most epic fighting battle room fighting begin.
[BELL RINGING]
MONSTER MASTER: [LAUGHS] Now you will perish. Gungador attacks with Severing Smite.
GUNGADOR: [GROWLS]
MOLLY BLOOM: Epic move that does zero damage?
MONSTER MASTER: Wait, what?
ALLIE: Yeah, sound waves are just energy disturbances passing through air, so you can't really hurt them.
GUNGADOR: Sound waves are vibrating air molecules!
ALLIE: Exactly. Nice recall, Gungador.
GUNGADOR: Gungador gets it again!
[CHIME]
Is Gungador genius?
MOLLY BLOOM: Allie, your turn to attack.
ALLIE: I'm going to play a tone and increase the pitch.
MONSTER MASTER: What is this pitch you speak of? Is it a laser, or a punch, or a laser punch?
ALLIE: Pitch is the word we use to describe how high or low something sounds. Remember how I told you air molecules wiggle in a soundwave?
GUNGADOR: Gungador remembers!
ALLIE: Well, the pitch comes from how many wiggles, or vibrations, each molecule makes over a certain amount of time. This idea is also called frequency because it has to do with how frequent the vibrations are. If those air molecules wiggle slowly, and they vibrate only a couple dozen times a second, then the pitch sounds low, like this.
[STEADY TONE]
But if they vibrate quickly, hundreds of times a second, then the pitch sounds high, like this.
[RISING TONE]
MONSTER MASTER: Ah, the noise is horrible.
MOLLY BLOOM: But it also does zero damage. Monster Master, your turn.
MONSTER MASTER: Gungador attacks with Beast Blast!
GUNGADOR: [GROWLS]
MOLLY BLOOM: And that does--
[BUZZER]
--also zero damage.
MONSTER MASTER: What?
ALLIE: Sorry. Remember how sound waves aren't hurt by punches or swipes?
MONSTER MASTER: Oh, yeah. [MUTTERING]
MOLLY BLOOM: [SIGHS] All right, this battle is so not epic. Very well, Allie, go again.
ALLIE: I'm going to take that tone I made this last round and increase the amplitude.
MONSTER MASTER: Amplitude, is that like attitude?
GUNGADOR: Gungador's attitude is biggest in land!
MONSTER MASTER: I don't think that means what you think it means, Gungador.
ALLIE: Actually, amplitude is related to volume or loudness. It means how much energy the sound wave is carrying. When you increase the energy, to us it sounds like the tone is getting louder. So if I take this tone
[STEADY TONE]
--and dial up the amplitude--
[TONE INCREASES IN VOLUME]
--it gets loud!
GUNGADOR: Can't hear own self thinking. Gungador too messed up to fight!
[ELECTRONIC WARBLING]
MOLLY BLOOM: Gungador loses a turn.
MONSTER MASTER: No fair.
MOLLY BLOOM: Back to you, Allie.
ALLIE: I'm going to use my soundwave to play music.
[MUSIC PLAYING]
Music is a combination of different frequencies and amplitudes, as well as things like tone and rhythm. Still, it's all just sound waves that are traveling through the air.
GUNGADOR: Gungador feels urge to-- dance? Gungador must bust a move. Hoo, ha. Hoo, ha.
MONSTER MASTER: Stop flailing about a fool and get ready for your next attack, Gungador.
GUNGADOR: No. Gungador found new calling in life. Gungador is genius who likes dancing-- no more battles!
MOLLY BLOOM: And that settles it-- Allie and the sound waves win.
ALLIE: Sweet. Woo-hoo!
MONSTER MASTER: No!
MOLLY BLOOM: That's it for this really weird edition of Most Epic Fighting Battle Realm. Game over.
GUNGADOR: Hoo, ha. Hoo, ha.
MOLLY BLOOM: We love getting your drawings. And you know what we'd love to see? Your drawings of Gungador fighting a soundwave. We think that would be epic, indeed. Send them to hello@brainson.org.
We're going to tickle the ivories a little more in a minute. But first, let's tickle your eardrums. It's time for the mystery sound.
[MUSIC PLAYING]
NARRATOR: Mystery sound.
MOLLY BLOOM: Here it is.
[SCRATCHING]
Stick around. We'll be back with the answer, a little later in the show.
[PIANO MUSIC]
Do you have a question for the show, or do you want to send us a mystery sound or a drawing? You can send them to us at brainson.org/contact. And if you're into actual mail-- the kind with paper, and stamps, and envelopes-- head to brainson.org. You'll find our physical mailing address on the Contact Us page. To thank the awesome kids who contribute their ideas and energy to the show, we add their names to the Brains Honor Roll, like Felix, from New Jersey. He has a theory about the sound in seashells.
FELIX: I would like to know how you hear the ocean in a shell? So basically, it's probably just the air rushing around inside the shell. So when you do hear the shell, well then it's not really the ocean-- it's just the air that you hear in the shell.
MOLLY BLOOM: Well, Felix, that does sound interesting. We'll have an answer to that question in our Moment of Um. Listen for that, and the latest installment of the Brains Honor Roll, at the very end of this episode.
You're listening to Brains On. I'm Molly Bloom. And today, we're talking--
[PIANO MUSIC]
--pianos.
[PIANO MUSIC]
ANDREW: There are black keys and white keys, and they all have different sounds.
SHAWN: In the bottom, it looks like sticks, and on the top it looks like marshmallows.
BRIELLE: I'm pretty sure there are, like, strings, maybe, that, like, when you press the key, then it vibrates and it makes a sound, I guess.
MARIBEL: Yeah, I think that's how it works.
ANDREW: Those sounds, like a deep voice, and it can make a high pitched voice, too.
BRIELLE: When I'm playing, like, something happy, I hit it harder than I would play with something sad.
MARIBEL: When you play something that's said, it's slower. And when you play something that's happier, you play it with, like, more pizzazz and a lot, like, quicker.
MOLLY BLOOM: That was Brielle, Maribel, Andrew, and Shawn. They're all students at Walker West Music Academy, in St. Paul.
[PIANO MUSIC]
You hear how that piano note is still going? It sounds like it's never going to stop. That's because of the sustain pedal. Most people think about fingers playing a piano, but there's a lot going on below the keys, too. Every piano has a set of pedals that you use your feet to push. Six-year-old Theo, from Woodbury, Minnesota, has this question.
THEO: Why do pianos have three pedals? Because I play piano a lot and I want 20.
MOLLY BLOOM: Hmm, 20? Oof, that is too many for my brain to think about, or I'd at least need a few more feet to handle them. Until you invent your 20-pedaled piano, most pianos are stuck with three. Push on the sustain pedal while you play a note, and the note rings out, even after your finger is off the key.
[PIANO MUSIC]
But what do the other pedals do? Let's go back to the Piano Shop, to get an answer from Carmen and Carl.
CARL SCHMIDT: Yeah. Generally on upright pianos, there is a soft pedal which moves the hammers closer to the strings, and it just kind of produces a softer tone.
CARMEN MANCINO: Pianos have different pedals, and they might not all be the same pedal on every piano. There's usually a soft pedal, which is the one, like Carl said--
CARL SCHMIDT: On the left, yeah.
CARMEN MANCINO: Yep, it's the one on the left, that moves the hammers just a little bit forward to make a softer sound in tone. And then another kind of pedal is a sostenuto, which is like the sustain pedal. On the sustain pedal, the sound keeps ringing, no matter which keys you're playing. But on a sostenuto pedal, the sound only keeps ringing on the first chord that you're playing. And then you can play other notes, and it creates a staccato effect when you're playing the other notes, while the first chord continues to ring.
MOLLY BLOOM: That's cool.
MARC SANCHEZ: Wow, I like that.
CARMEN MANCINO: What other kind of pedals are there?
CARL SCHMIDT: There's a pedal that basically drops a sheet of felt in front of the hammers-- in between the hammers and the strings. And that is considered a silent pedal.
MARC SANCHEZ: So if you wanted to play, maybe, really quietly at night and not wake up the neighbors.
CARL SCHMIDT: Yeah, that'd be the one to use.
MOLLY BLOOM: Thanks to Carl and Carmen for that pedal explanation. OK, let's go back to that mystery sound. Wanna hear it one more time? Here it is.
[SCRATCHING]
Any guesses? Did you change your mind after you heard it a second time? Well, here with the answer is Mathis, from Piedmont, California.
MATHIS: That was the sound of me, running my thumbnail against the sixth string of my guitar.
MOLLY BLOOM: So you might be picturing just a regular old string. Well, it's not. It's actually a tightly wound coil of metal. And those strings are similar to the strings that make the lower notes on a piano.
[MUSIC PLAYING] Ba, ba, ba, ba, ba, ba, ba, ba, ba, ba, ba, Brains On.
MOLLY BLOOM: Now we know about the pedals, and we know about the keys, and we know a bit about the action. But there are thousands and thousands of parts inside a piano that all work together. There are so many parts that you'd really need to work in a piano factory to know about all of them.
BOB BERGER: My name is Bob Berger. I work at Steinway and Sons as Director of Customer Satisfaction. I grew up here in New York City. I grew up in Astoria, which is where the Steinway factory is located. I was hired here as an engineer many years ago-- almost 30 years ago. I know the pianos pretty well.
MOLLY BLOOM: Since Bob knows pianos inside and out, we decided to play a little game with him. We gave him 30 seconds to name as many parts as he could. Time starts now.
BOB BERGER: Pedals, lyre box, lyre pillars-- hammer, hammer shank, knuckle, repetition, fly, jack, let-off screw, treble wire, bass wire, grand piano plate, soundboard, bridge, front rail, keybend, keybend endcaps, keyboard, sharps, naturals, cap stands, action hangers.
[BUZZER]
MOLLY BLOOM: Wow, that was amazing. Some of those parts sounded familiar, but others I had never heard of before. Putting a piano together is a feat of engineering, but let's not forget the builders and the musicians who are also involved.
BOB BERGER: You need expertise in wood technology, and finishing, and adhesives, and metallurgy, and acoustics. The piano, and certainly the Steinway piano, is probably the most highly-engineered acoustic instrument that exists. And that's because of the force of the strings on the case is incredible.
It will range from anywhere from 20,000 to 35,000 pounds of force. And this type of force needs to be controlled. And you need to have a structure that's very stable, that will not move under that tremendous force. And it's made out of wood and metal. And it's a very challenging, interesting product to make.
[PIANO MUSIC]
MOLLY BLOOM: Pianos are complicated machines that make beautiful sounds, by striking a key, which triggers the action, and that hammers a string, and that string vibrates to make a sound. Sound is made up of vibrations moving through the air and that's what we hear. Who could forget sound waves? Right Gungador?
GUNGADOR: Sound waves are vibrating air molecules! Gungador gets it again!
[CHIME]
MOLLY BLOOM: Thanks to Nancy Yang, Allie Hinsey Francis, and John Miller. We had engineering help this week from Michael Demark and Veronica Rodriguez. Special thanks to Keys 4/4 Kids for hosting us. Part of every piano sale there goes towards putting another piano in someone else's home-- Very cool. And now for the Moment of Um.
ALL: Um, um, um, um, um, um, um, um, um, um, um, um, um, um, um, um, um, um,
MOLLY BLOOM: Remember, Felix had a question about why people say you can hear the ocean in a seashell. He had a theory, too.
FELIX: When do you hear the shell, it's probably just the air rushing around in the shell.
MOLLY BLOOM: So is Felix right?
STEVE ERREDE: He's correct.
MOLLY BLOOM: That's Steve Errede. He's a Professor of Physics at the University of Illinois. He's here to tell us more about how seashells trick us into hearing the ocean.
STEVE ERREDE: If you have any arbitrarily shaped container-- for example a pop bottle-- there will be resonances of sound at certain frequencies, because of the shape of that container. And the shape of the container actually dictates what those resonant frequencies are so. If you blow across the mouth of a pop bottle, you will hear a pitch.
[BLOWING SOUND]
So if you have a shell, the shell has a different shape from a pop bottle, obviously. That shape dictates what kinds of resonances, at certain frequencies, it will have. The air is actually oscillating in and out of the shell. When you turn it from side to side, you can hear different resonant frequencies. And that's sort of reminiscent of the sound of waves crashing on the beach at an ocean, so people say you can hear the ocean in a seashell
[BLOWING SOUND]
ALL: Um, um, um.
MOLLY BLOOM: OK, it's time for the Brains Honor Roll. If you've recently sent us an email with a question, or mystery sound, or drawing, please be patient. The list is growing but the wait is worth it. Here's a podcast high-five to all our listeners who keep this show going with their energy and ideas.
[MUSIC PLAYING]
[LISTING HONOR ROLL]
[MUSIC PLAYING] (SINGING) Brains are all alive.
MOLLY BLOOM: Thanks for listening.
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