- [Rob] Are you feeling curious?

- [Curious Crew] Yeah!

- I'm so glad.

Today on "Curious Crew."

(electric guitar playing) It's a guitar jam session.

(laughing) Oh, very nice.

And some very instrumental investigations.

(upbeat music) (Kian gasping) - That's really cool.

- We have sound.

- So rock out with the crew as we explore guitar science.

Little air guitar, everybody.

(guitar music) (Rob harmonizing) - [Announcer] Support for "Curious Crew" is provided by MSU Federal Credit Union, offering a variety of accounts for children and teens of all ages while teaching lifelong saving habits.

More information is available at msufcu.org.

By the Consumers Energy Foundation, dedicated to ensuring Michigan residents have access to world-class educational resources.

More information is available at ConsumersEnergy.com/foundation.

Consumers Energy Foundation, supporting education and building sustainable communities in Michigan's hometowns.

And by viewers like you.

Thank you.

(uplifting music) (pencil scratching) - Hi, I'm Rob Stevenson, and this is- - [Curious Crew] "Curious Crew!"

- Welcome to the show, everybody.

We always like to start every episode with a couple of discrepant events, because discrepant events stimulate- - [Curious Crew] Curiosity!

- That's exactly right.

And I've got some fun ones for you today.

You're gonna notice we have a couple of guitars here on the table.

We've got an electric, (pencil scratching) (arrow twanging) and we've got an acoustic.

(pencil scratching) (arrow twanging) And first thing, Nash, I would like you to report out on the sound difference between these two guitars.

Do me a favor, give this one a strum.

(electric guitar playing) Oh, that's nice.

That's nice.

Okay.

Little comparison.

(acoustic guitar playing) What are you noticing, Nash?

- So the acoustic sounds more like you're playing it with an echo.

- Ooh, playing it with an echo.

So we got a full sound going on over here.

Excellent, okay.

Patrice, you're gonna help me out with this.

This is a little pitch pipe here.

Can you give me an A?

(pitch pipe playing) (Rob humming) (Rob singing) Patrice, what did you notice?

- There was an echo when you sang into the guitar.

- Excellent, okay.

Let's try this, I'm going to cover up this sound hole for just a moment, and I'm going to pluck this string, and I'd like you to report out the difference of when it is covered and when it is not.

You ready?

(guitar playing) What'd you notice?

- It was a lot louder, and it added a little base to it once you uncovered it.

- Nice, so a little base coming out of there?

- Yes.

- Okay, excellent.

So we've got some interesting discrepant events here with these guitars.

Now, I'm gonna invite three of you to do a little scientific modeling to see if you can explain these phenomena by the end of the show.

And of course, you can revise your thinking based upon what you learn throughout the show.

So who would like to do a little modeling moment today?

Who would like to do a modeling?

Okay, Emmanuel, Carmela, and Bhavya, excellent.

Now, does anyone have a prediction what we're going to be investigating today?

What do you think?

What do you think?

Kian, what do you think?

- Well, it looks like guitars.

- We are definitely going to be exploring guitar science.

Stick around.

This episode will be music to your ears.

(upbeat music) - So let's try to figure this out.

What did you notice, Carmela?

- There was definitely a difference in the volume of the two guitars, and the electric guitar was a lot quieter.

(air whooshing) - That surprised me.

I must be used to hearing an electric guitar plugged into an amplifier.

- Me, too.

And did you notice how the guitar echoed when Dr.

Rob sang into it?

- Yeah, it was the same note that he plucked.

I'm pretty sure that's not a coincidence.

(upbeat music continues) - As far back as 5,000 years ago, people were playing guitar-like instruments like the satara.

And those early stringed instruments influenced the design of the first guitars in the 15 hundreds.

Modern guitars still have some of those general parts.

There's a body, a fretboard, a headstock, tuning pegs and strings.

Whether playing an electric or acoustic guitar, the strings get plucked, picked, or strummed to produce a vibration.

Even today, guitars are played throughout the world, and are used in many different styles of music.

(soft music) (air whooshing) (techy music) (air whooshing) (upbeat music) So as we dig into guitar science, the first thing I want to compare is an acoustic steel string with a classical guitar.

So you'll notice it's a little smaller, it's a three quarter size, but I'd like to do a little comparison.

Let's start on the very end here.

And I wanna point out the difference with the bridge.

See how this one has pins going in there?

And this one, notice how the strings actually wind around.

Now, speaking of strings, these ones, (guitar playing) (pencil scratching) (arrow twanging) steel.

These ones, (guitar playing) (pencil scratching) (arrow twanging) nylon.

Okay?

As we move up the guitar, you're gonna notice that the neck on the classical guitar is pretty wide.

That actually is really helpful when you're learning to play the guitar, whereas over here it's a little skinnier, so you have to have those delicate fingers.

Then we move all the way up to the headstock.

And notice we've got the tuning pegs that are all metal over here.

But on the classical, we have a combination of plastic and metal.

Bhavya, I have a question for you.

What's the point of the tuning pegs?

- Well, they're used to tune the guitar, and by turning them tighter, that makes the strings tighter, which makes a higher pitch.

And by making them looser, that makes the strings looser, which makes a lower pitch.

- That was an outstanding explanation!

Excellent job!

And in fact, Kian's gonna help us demonstrate this.

We got a little box over here, don't we, Kian?

Give us a little strum on that rubber band.

(rubber band playing) Oh, that's nice.

Okay, I'm gonna place this other little dowel in here, and you keep plucking away, and let's have a little fun.

(rubber band playing) Let's shorten it.

(rubber band playing) Nice job.

So you mentioned tension, but we're also looking at the length of the string that we're playing making another difference.

Okay?

Callan, have you ever seen one of these before?

- Yeah.

- Yeah.

This is called a capo.

(pencil scratching) (arrow twanging) What do you think this is for?

- To clamp the strings.

- To clamp the strings.

Now, let's get a sound in your head.

(guitar playing) Try to get that in your head.

I'm gonna put this on the fifth fret.

I'll use this little position marker to help me identify it.

And, Callan, what do you think it's gonna sound like now?

- I think it's gonna be higher.

- "I think it's gonna be higher."

(guitar playing) Which makes sense, right?

We actually have three quarters of the length of the strings left.

And so what had been an original E is now playing an A.

Let's move it again.

If I go over here to the seventh frat, it's gonna be higher still, don't you think?

Listen how beautiful this sounds.

(guitar playing) Oh, that's mellow.

And now we got a little B sound coming right out of there.

Excellent.

So we've seen two different ways to adjust the pitch, tension and also the length of the string.

Capos are a lot of fun because you can actually change the tune of the guitar without retuning the guitar.

Hey Kian, play us out.

Play us out (rubber bands playing) (animation whooshing) The crew discovered a couple of different ways to change the pitch of the guitar's six strings, but not all guitars have six strings.

In fact, there are guitars with four, seven, eight, 10, or 12 strings.

Guitars with additional strings have a fuller sound.

(guitar playing) Now, when tuned, the six-string guitar's notes are E, A, D, G, B, and E. Although guitar strings are made of different materials, have different gauges and winding patterns, electric and acoustic guitars use steel strings, while the wide neck classical or Spanish guitar uses nylon strings.

Looks like you're tuned up and ready to play.

(soft music) (techy music) (upbeat music) So Ilaria, I have a question for you.

What are two of the ways we've already discovered to change the pitch on the guitar string?

- Length and tension.

- Length and tension.

And here's another way, too.

In fact, it has to do with the mass of the strings.

I want you to notice these two boards here.

I have a similar length string on both of them, and there's under similar tension.

The interesting thing is this is actually a guitar string, (pencil scratching) (arrow twanging) and this is fishing line.

I'd like you to notice the difference.

(guitar string playing) (fishing line playing) (Rob laughing) You can totally hear that difference, can't you?

This is a much deeper sound, which makes sense.

And if we look at a guitar, we can actually see how that mass changes from these really slender high strings, (string playing) to these much more massive lower strings.

And what's incredible is this string right here is actually vibrating at 83 times per second.

This one over here, (pencil scratching) (arrow twanging) 110.

Now, I wanna focus on that one for just one second.

Caleb, I want you to help me out for a moment.

I'm going to pluck this string, and pluck this string, and I'd like you to compare for me what you notice.

(strings playing) - Well, the one from the guitar is a lot deeper and fuller.

- [Rob] Oh, I like that.

That's- - A lot louder.

- A lot fuller, a lot louder.

Excellent.

And here's why.

When we pluck this string, it's disturbing the air particles and those waves travel to our ears as sound, but it's only hitting so much air.

And in fact, we get the vibration going down into the board, and so it'll get a little bit more air particles involved.

But look at how much is involved in a guitar, okay?

When we pluck this string, we've got a lot of surface area to vibrate both on the outside as well as on the inside.

So we get all that air on the inside that's gonna react as well.

Now we're gonna talk about the anatomy of a guitar.

Caleb, pick up that neck and headstock for a second.

What do you notice about that?

- It's very heavy and bumpy.

- It's heavy and bumpy.

And, in fact, if you turn it around, we can show that there is a rod inside there called a truss rod.

(pencil scratching) (arrow twanging) Now, that truss rod is really important for stability with a guitar.

Let's think about why.

You can put that down for a second.

If I've got six steel strings that we tune and tighten, and tune and tension, all of that, do you have any idea how much tension is on this guitar?

This is crazy.

About 200 pounds!

200 pounds!

Why doesn't this guitar just whoop, fold right up in half under all that tension?

Well, we know there's going to be a truss rod in there, but think about the soundboard.

This is only two and a half millimeters of spruce wood.

That is not very thick!

So what do we do, Patrice?

- I noticed that it's like pieces of wood, I guess supports that actually help with the tension.

- You are spot-on.

These braces are critically important.

And in a steel guitar like this, we use what's called an X bracing so we can make it a lot more rigid.

Now, we still want it to flex, 'cause we still need that sound to vibrate.

And a luthier, person who makes guitars, will be shaving off material, shaving off material, so we can get the right tap tone to it.

Amazing.

But we need this to be able to vibrate like mad.

The anatomy of a guitar.

Amazing engineering accomplishment.

Very impressive.

(animation whooshing) The engineering of a guitar's soundboard is important so it can withstand all the pressure from the tension of the strings.

We saw how the bracing under the top can make the thin wood more rigid, but it still needs to flex back and forth to pass the vibration to the surrounding air.

The acoustic guitar primarily use the X brace pattern, but classical guitars have many different patterns to get the top to flex and produce different modes of vibration.

Sounds fantastic.

(guitar playing) (upbeat music) Oh, static electricity.

Now, that would be shocking, wouldn't it?

- In the static electricity episode, Dr.

Rob had this big Van de Graaff that was standing next to him on the table.

- We need another look at this Van de Graaff generator.

- And he took this little wand, it looked like, and he had these little pie pans that were stacked on top like a hat on the Van de Graaff.

- Janellyn, what do you think's gonna happen?

- The tins will probably fly away everywhere.

And then he took the wand and he approached the Van de Graaff, and then all of a sudden all the pie pans just started like flying off and floating off of the Van de Graaff.

- That was a good prediction, Janellyn.

(laughing) (upbeat music) (heroic music) - [Announcer 2] STEM challenge.

- So have you been having fun investigating guitar science today?

- [Curious Crew] Yeah!

- I'm so glad.

Take a look at this.

I have this little half tube which I've stretched some rubber bands over, and I have a really simple rubber band guitar.

(rubber band guitar playing) (Rob laughing) Now, I'm upping the challenge for your STEM challenge.

Not something so easy as this.

You are going to be designing a homemade guitar.

Now, I know you have a lot of parts cut and prepped.

Are you ready to start your build?

- [Curious Crew] Yeah!

- All right, get to it.

- Oh, maybe you could work on these, and I could work on the short things.

(video popping) - Today, Dr.

Rob has us making guitars.

(video popping) - I think we put it like this.

Does that look right?

- The materials we're using are a desk drawer, a plank of Pinewood, some actual guitar strings, and then some piano tuning pegs.

(video popping) - My table decided to split up the work and each have different roles.

- World tour.

- World tour.

(laughing) "Curious Crew" world tour.

(video popping) - My advice to someone trying this experiment at home is just to keep on persevering and trying different things until you get an amazing guitar.

- Ugly.

(guitar playing) (Kian gasping) - That's really cool.

- We have sound.

(video popping) - Our guitar turned out really good.

It made an amazing sound.

It was very finely tuned.

(guitar playing) - This experiment is really fun because you get to make your own musical instrument, and your ideas can really just come to life and create something amazing.

(video popping) - That's a work of art right there.

(video whooshing) - So it looks like my luthiers are hard at work, these skilled guitar craftspeople.

Very impressive, my friends.

So I'm curious how these turned out.

I'm gonna start over here with you, Caleb.

Tell me what you and your team used there in your guitar.

- We have an old desk drawer made out of walnut.

- [Rob] Nice.

- Blue and green tape, actual guitar strings.

- [Rob] Okay.

- A wooden spool.

And then these things are used for tuning a piano.

A plank of pine wood.

And then of course, the "Curious Crew" sticker.

- (laughing) Of course.

So Nash, would you mind picking that up and giving it a strum?

(upbeat music) (guitar playing) - Oh, very nice.

Carmela, tell me what your team used.

- We screwed in these fishing lines, and we tied them to these piano tuning pegs, and we just added them to this wood.

And then we also have a wooden dowel, which we can use to tune the strings.

- Oh, very nice.

Okay, Kian, would you mind giving us a strum there?

(guitar playing) So Patrice, how about your table?

What materials did you use?

- Our team used paint paddles, a hand drum, and a wooden spool along with two pieces of fishing line, and two pieces of wire.

- All right, let's give that a straw.

Ilaria, are you gonna be doing that for us?

All right, let's take a listen.

(guitar playing) That is awesome, and I noticed that you can actually tune yours over there with those little screws up on the top.

Well done, luthiers, now we can really appreciate those skilled guitar craftsmen out there.

This is a task you can try at home.

The most challenging part, coming up with a system where you can actually tune the strings.

Try it!

(animation whooshing) We've seen how guitar strings transmit vibrations through the saddle, bridge, reinforced soundboard, and resonate through the sound hole.

And how the string's mass, density, tension, and length determine pitch.

But how is pitch calculated?

(animation whooshing) The Western music scale has 12 half steps in a single octave.

So guitar luthiers divide the playable strings so that each fret increases the frequency by two to the one twelfth power.

This makes the frequencies go up by half step in each fret.

So by pressing the 12th fret, the string is half of its original length, and will produce a pitch one octave higher.

Amazing design.

(gears rattling) (techy music) (upbeat music) So we have an electric guitar here, and you're gonna notice there's a lot of similarities between this and the acoustic guitar.

But a big difference are these electronic pickups.

And let's talk about that.

So I've taken one apart, and you'll notice I've pulled off the bobbin, and it's revealing this copper wire.

And I wanna point something out on the bottom.

I've got this iron pair of pliers, and I'm gonna touch this against here.

Emmanuel, tell me what you notice.

(pliers thudding) - It made a loud thud noise.

It magnetized.

- Yes, it's also magnetized.

Now, that's really important.

The bottom of this is a magnet, and these pegs become magnetized.

Now, if we wrap wire around there, we can actually induce an electrical volt.

Let me show you what I mean by that.

So I've got a little tuning fork.

Okay?

And Carmela, what do you think's gonna happen if I strike the tuning fork and hold it over the pickup?

- I think you'll be able to hear the tuning fork louder.

- Oh, let's try it.

(tuning fork clinking) (tuning fork playing) - Wow.

Isn't that incredible?

So the moving tines are moving through the magnetic field, and that's inducing electricity.

And suddenly, that mechanical energy is turned into electrical energy, goes to the amplifier, back to mechanical energy, and we can hear it as sound, which is unbelievable.

I'm gonna do it one more time.

(tuning fork clinking and playing) Oh, yes.

Now, so we know that there was a little bit of an interference there.

Could you hear that sort of buzz?

Now, there's a way to work around this.

This is another kind of pickup.

There's two of them.

This is called a humbucker.

(pencil scratching) (arrow twanging) And we've got the magnetized inverted.

So we got one magnet one way, one magnet the other way, and it actually has a cleaner sound when you're playing the guitar.

Now, guess what I did here.

Can you tell what I did there, Nash?

- Is that a magnet wrapped in a bunch of wire?

- (laughing) That's exactly what it is.

And, in fact, I can hook this up to my amplifier, and do it with the tuning fork as well, and you'll see it, it is magnetized.

It just doesn't produce as much sound.

Why do you think that would be?

What do you think I could do to increase the sound, Carmela?

- Can you wrap more wire around it?

- That's exactly right.

I could wrap more wire around it, because in this pickup right here, there are thousands of coils.

Way more than the 250 that I wrapped around my magnet.

Now, we are lucky we happen to have someone here at "Curious Crew," our own sound engineer, Drew, who plays a pretty good guitar.

You ready to hear a little jam session?

- [Nash, Emmanuel, And Carmela] Yeah.

- All right, let's take a look.

Come on out, Drew!

(electric guitar playing) - Drew!

Drew, Drew!

We're good!

Thanks.

Wasn't that amazing?

Alright, we're gonna try one more thing.

Do you recognize this guitar?

I'm going to put in this little pickup right there, and turn your guitar (guitar playing) into an electric guitar yourself.

Perhaps one of you can learn to to play like Drew.

And if not, there's always air guitar.

(guitar playing) (animation whooshing) There are many similarities between acoustic and electric guitars.

The guitar body, strings, fretboard and tuning pegs.

But there are differences, too.

The acoustic guitar is hollow and bulkier, while the electric is thinner and smaller.

The acoustic guitar's sound is magnified by the large soundboard and through the sound hole, while the electric guitar relies on pickups to convert the vibrations into electrical energy, and has other controls to change the tone, the volume, and even the pitch.

And the thick string bass guitar adds a lot to any rhythm section.

Encore!

(guitar playing) (upbeat music) - Are you curious about careers in science?

(animation whooshing) Hi, I'm Janellyn.

(air whooshing) This is Janellyn.

(air whooshing) It's Janellyn.

Are you curious about careers in science?

I know I am.

Being on "Curious About Careers" has just been amazing.

(air whooshing) I've gotten to interview some people in careers that I didn't even know existed until I got to interview them.

And there's a career out there for everyone.

What I want other girls to take away from "Curious About Careers" is to show them what's out there.

(air whooshing) (electricity buzzing) At the end of each segment, I always say a little punny line.

I had an eye-opening experience.

Spending my spare time with... Gotta jet.

(airplane whirring) It's always a lot of fun trying to think about what I'm going to say and how it's going to relate.

And I always say, "Explore your possibilities!"

The whole purpose of that is to encourage people to explore what they love, and to just keep asking questions and keep learning.

(upbeat music) I had an awesome time.

(air whooshing) I had a wonderful time.

(air whooshing) I had an ultra fun time.

(air whooshing) Explore your possibilities!

(upbeat music) And now, back to "Curious Crew."

(upbeat music) - So we know that the guitar strings vibrate the air around them.

- Right, but the string on the board couldn't produce as much sound just like the electric guitar.

- Exactly, because the guitar's soundboard and body resonate, too.

But the electric guitar was solid, which must have affected the volume.

- Yeah.

I'm thinking that because there are so many particles inside and outside the guitar, there are more particles that can vibrate.

Yeah, and those particles must have vibrated when Dr.

Rob sang to the sound hole, too.

(upbeat music) - So Drew was amazing.

Little air guitar, everybody.

(Rob harmonizing) (guitar playing) Unbelievable.

Okay, have you had fun investigating guitar science today?

- [Curious Crew] Yeah!

- I'm so glad.

So I know you've been thinking about string theory, but now it's time to face the music.

What have you figured out about playing unplugged, Bhavya?

- Well, we know that the electric guitar is a lot quieter than the acoustic guitar, especially when the electric guitar has a solid body.

- Yeah.

Both guitars' sound comes from the string, but in the acoustic guitar, the air can resonate better because of the hole.

- Excellent.

Okay, very good thinking.

So let's do a quick comparison again.

We'll strum it over here.

(electric guitar playing) Can you feel a vibration?

- Yeah.

- Oh, how about that?

Okay, how about this one?

(acoustic guitar playing) Put your hand on there.

Can you feel the vibration?

- Yes.

- How about that?

Now, we know the sound is coming from the strings, right?

But it's going to be disturbing the air that is going to be sending the sound to our ears.

Now, as the string goes through the guitar, it will vibrate the body, it will vibrate the neck, but the major difference is going to be the sound hole.

And you're right, we've got more air in there, and if there's more air to be disturbed, we get a fuller sound.

So how does that impact the resonant air, Carmela?

- Well, we think that you sung a certain note into the guitar, which vibrated the air in the guitar, and made it resonate.

- And when you plucked the string, the sound kept resonating until the cardboard stifled it.

- Okay, excellent.

So you're really noticing the difference between whether that sound hole is closed or open.

(guitar playing) Yeah, we can really hear that resonance.

Now, this is a great example of something that's called helmholtz resonance.

Now, I'm gonna demonstrate this real quick.

How many of you have ever blown into an empty bottle before?

Okay, gotta do it.

(bottle playing) I love that sound.

Okay.

It depends on the volume of air, but it's gonna produce a certain pitch, right?

The same is true for the guitar.

I sang the A note, and that resonated inside the guitar.

And in fact, what's amazing is we have to remember that that air is acting like a big spring going in and out of that guitar.

Beethoven once said, "A guitar is an orchestra in itself."

So remember, my friends.

- [Rob And Crew] Stay curious!

- And keep experimenting.

(animation whooshing) Get your CuriosityGuide and see more programs at wkar.org.

- [Announcer] Support for a "Curious Crew" is provided by MSU Federal Credit Union, offering a variety of accounts for children and teens of all ages while teaching lifelong saving habits.

More information is available at msufcu.org.

By the Consumers Energy Foundation, dedicated to ensuring Michigan residents have access to world-class educational resources.

More information is available at ConsumersEnergy.com/foundation.

Consumers Energy Foundation, supporting education and building sustainable communities in Michigan's hometowns.

And by viewers like you.

Thank you.

- Patrice.

(Rob blowing raspberry and laughing) (monitor beeping) (upbeat music) (Rob laughing) (Rob and Kian singing) (monitor beeping) (guitar playing) (laughing) No, that was awesome!

Yeah, check them out!

Check them out!

These are like, so cool!

I want a pair!

(monitor beeping) (guitar playing) (soft music)