>> ♪ We've got two days to get this straight ♪ We've got a challenge just won't wait ♪ Our eyes are on the prize ♪ An engineer just set the date ♪ We've got this client can't be late ♪ Oh, no it's go time ♪ Build it, test, fix it debug now and kick it ♪ Got to get it off the ground yeah ♪ Stick around and you'll see what teamwork's supposed to mean ♪ It's so key Design Squad ♪ Design Squad.

♪ >> Filling tank.

Fingers crossed.

Need a countdown.

Three, two, one.

There it goes.

>> No way!

>> Uh-huh.

And to there.

Carmel, anyone?

>> Thank you.

>> All right, Design Squads, now, tell me, do you have any idea what today's challenge might be?

>> Dog sleds.

>> Dog sleds was last time.

All right, turn around, roll the tape.

Let's watch it.

>> Food!

>> Hey there, I'm Rob Gregory, Redbones Barbecue.

And we know barbecue.

And we're having a big old street party here at Redbones benefiting the New England Mountain Bike Association.

We're a bike-friendly place here.

And we're the only barbecue joint in the country that has valet parking for bicycles.

We do a lot of benefits like this, lots of street parties benefiting all kinds of good causes.

And that's where you come in, Design Squads.

We're going to be having a big pig roast to benefit the homeless.

The key to this pig roast is a real low and slow rotisserie.

I want you to build a rotisserie.

It must run by human power.

It must be inspired by bicycles.

And it must have a speed control.

Redbones will supply the grill, and we'll use the winning rotisserie at our next benefit street party.

Good luck, Design Squads.

>> Don't blow it.

>> Yeah.

>> Rotisserie.

>> What do you guys think of that?

>> Yeah.

>> Good stuff.

So a human-powered rotisserie that's bicycle inspired.

And it's got to be slow, so you need a speed control.

We want you to have some kind of energy storage mechanism, which is where that Rube Goldberg machine comes in-- to inspire a couple of ideas.

And there's a big, huge grill from Redbones outside.

>> Cool.

>> Sweet.

>> Are there any questions?

>> Do we get to go to the party?

>> Yes, you get to go to the party.

Start brainstorming.

>> Yeah.

>> All right.

>> Yeah.

>> Anyone know how to unicycle without any pedals?

>> Greasy.

Eww.

>> We have a lot of wheels, a lot of bike wheels.

>> Yeah, brother.

>> When I heard what the challenge was, I was pretty excited.

I mean, coming from Texas, you know, barbecue is in my blood.

A human powered bicycle theme rotisserie?

That was a pretty cool idea.

>> Yo, you guys want to go see the grill?

>> Yeah.

>> Come on, come on, come on.

I'll show you.

>> Let's check out how it turns.

>> This is the actual rotisserie.

You guys are building the bike-inspired human-powered speed-controlled energy-stored mechanism that makes it spin.

>> Where's the pig go?

>> Right in here.

>> Inside?

>> Uh-huh.

>> So our machine's going to attach to this gear right here that turns it, and that's it.

>> If your machine was to attach to this whole thing in only one place, that is definitely where you'd want it.

>> All right, cool.

>> How are we going to get it to go at a constant speed?

>> Don't they do that for, like, clocks and things?

You wind them up, and that doesn't matter, but the clock has to go at a constant speed, because it's a clock.

Like, I know my clock works with weights, so when you crank it, you life a weight up, and then the weight falls down gradually.

>> Do you guys want to look on the Internet, get some ideas?

>> I don't know how to draw a pig.

>> Looks like bacon.

Has to be controlled speed, has to be inspired by a bike, and it has to have some kind of energy storage, right?

>> Stored energy is called potential energy, because it has the potential to do work.

One way to build potential energy is to raise an object against gravity, like biking up a hill.

Once at the top of the hill, stored energy can now be used to do work.

If a bike coasts down the hill, gravity then converts potential energy into kinetic energy, or energy of motion, by pulling the bike down the hill.

And there are many ways to convert potential energy into kinetic energy.

>> Yeah, like water.

Kind of like a water wheel.

>> Water?

>> Yeah, like water.

You know, I want to smack you.

>> How do you mean?

>> Like, as you pedal, for example... >> Try it.

>> Well, okay.

As you pedal... say this is the back wheel of the bike.

Let's just say you pedal, it drives water up.

>> Pedaling a pump.

>> Yeah, that'll force the water into this big container, okay?

There's your potential energy, because gravity will drive it down.

>> Like, if you have cups in here where you put water in, like here, and this is a rotisserie, so the water falls down, it makes the big wheel spin, which spins the rotisserie.

So let's get started with a design.

Want to draw it out?

>> Yeah, let's draw it out.

>> Yeah.

>> We were looking up how a grandfather clock worked.

You have this special gear.

It's, like, a gear, but it's shaped like that, kind of, so it can only go in one direction.

And you have this thing called an escapement.

And it's regulated by a pendulum.

And so when it swings, it lifts up on this escapement, which is what allows the gear to turn.

And the thing that's causing the gear to turn, a weight's applying a force trying to turn this gear.

So maybe we could use that, like, if they pedal on the bike, it'll wind up your weight, and then as the weight falls, that would be what turns our rotisserie.

Could we build a sketch model of an escapement just so we could see if it works?

>> That's a really good idea.

>> We've got the gears to go on this wheel, so therefore we can turn it along with the wheel.

We can put some kind of sprocket on the shaft of the rotisserie, and then having a chain connecting this wheel to the sprocket on the rotisserie, so that when this spins, the chain converts the energy and spins the rotisserie.

So we put this here, the sprocket goes there, here.

That's where we're going to put the other sprocket.

>> And you're going to use a chain?

>> Yeah, the chain's going to keep the sprockets right here.

>> Got you, got you.

>> And we can have the big tank right there, dropping right here.

>> Sure.

So the water will come down from there, and it will hit this, and it will turn that.

And as this turns, it'll turn the rotisserie.

>> Right.

>> Cool.

How are we going to mount this onto the grill?

>> Let's weld some pieces onto the fork.

>> Sure.

>> And see where we can place it.

>> Can you weld one here and one here, just like this?

As close to the edge as you can get it.

>> Okay.

>> Here, pick up the wheel.

>> That could work.

>> We're making a mockup of the pendulum and the escapement.

This is the escapement, which regulates the speed that the wheel turns.

>> What's that?

>> What do you mean, what's this?

Can't you tell?

>> It's not very symmetrical.

I can't tell nothing.

>> It's a mockup.

Don't worry, it'll be straight in the final product.

This is the rod, and I'll be attaching the weight to the end of this.

>> Is it spinning?

>> Well, it could be better.

>> Do you like the other one?

>> Yeah.

We need a seat.

>> Let's see outside.

>> It's huge.

>> I like that seat.

It's comfortable.

If you're on there for 40 minutes you should get a comfortable seat.

Now, that's a seat.

Oh, yeah.

Whoo!

>> We should make a stand for the bike.

>> Look at these bikes.

>> Do you know how to ride a bike, Lindsey?

>> No.

>> Don't forget to wear a helmet.

>> Don't miss the door.

>> Is this facing the right way?

>> All right, I've got all the supports made.

>> And I just put all the nuts and bolts.

>> Oh, that looks great.

Does it hold?

>> Oh!

>> Annelise.

>> My foot, man.

>> Wrap it up, D squads!

That's the end of day one!

>> All right.

>> Nice work.

>> If our team wins, then it'll be a three-way tie for second with me, Lindsey, and Juan, which is really cool, because I totally thought I was completely out of the running.

>> I do feel the pressure of this, but I try not to think about it, and just try to keep my team working.

>> All right.

>> What are we going to do today?

>> Everything.

>> I guess we have your wheel with the escapement that has to attach directly to this.

>> Let's bring the forks of the bike that we have, and the wheel, to see where we're going to place the measurements, and let's cut some metal.

>> All right, let's go.

>> Sure, let's do that.

>> Yeah.

>> Let's get to work.

>> Go and do it.

>> We can put this piece on the rotisserie.

>> This is going to be attached to the shaft of the rotisserie.

>> I'm going to weld the bearing to the gears.

>> That's really good.

>> Ready?

Watch this.

That's so cool.

>> Hi-ho, Green Team.

>> Hey, Nate.

>> I've got Rob from Redbones.

>> Hi, Rob.

>> How's it going, Rob?

>> Hey, how are you, guys?

>> Why don't you tell him what you're buidling?

>> So we have a two part system-- a bicycle that people bike on, and it lifts a weight.

And then as the weight drops, it turns this wheel right here.

But the speed at which the wheel turns is regulated by an escapement system.

>> Yeah, it's similar to a grandfather clock.

This is just a mockup right now.

>> I really like the idea of haiving a grandfather clock cook a pig.

>> Slow roast, very slow.

>> That's a good one, yeah.

>> Nice meeting you.

>> Go for it.

Good luck.

>> Take it easy.

>> Hey, guys.

What's it going to look like?

>> What we're doing is using water to power the rotisserie.

>> Water.

>> Yeah.

>> Well, the bike's sitting here, which you pedal.

>> Yeah?

>> And then as you pedal, it'll use the pump.

As you pump, water's going to be coming down.

>> So the water dripping down is going to turn this, which turns this, which turns this.

>> Unbelievable idea, and I'll believe it when I see it.

>> All right.

>> But I like it.

I like it.

>> Cool.

Nice work, guys.

>> Yeah, nice work.

Yeah, nice to meet you all.

Take care and good luck.

>> Thanks so much.

>> On this, there's a ratchet system, so you can only spin the wheel one way.

>> Right.

>> When someone's pedaling backwards, the wheel doesn't move.

What happens is if you pedal backwards, it turns this.

This cranks up our weight.

And then when you stop pedaling, the weight should fall down with the potential energy spinning the wheel forward.

And it should move the rotisserie as well.

>> Figure right here?

>> Yeah.

>> And we line it up, it'll be exactly on the Xs.

>> Sure.

>> All we need is to bring the welder outside, put her on here, it'll work.

>> We need to cut the pipe down.

>> Cut what pipe?

>> The steel tubing.

It's in the middle of the thing.

>> The middle of what?

What steel tubing are you talking about?

This one?

It's fine.

We can do it later.

>> Whatever.

>> You want to cut it?

>> It's your scholarship.

Whatever you want to do.

I don't care.

>> Oh, that's a brilliant attitude.

>> Don't talk to me about attitude, dude.

>> Hmm?

>> They seem like a married couple, Juan and Zach.

Juan does seem a little stressed.

I guess it's because if Juan wins this challenge, he's going to be up with Wes for the finale, so he wants everything perfect, and, like, everything to run smoothly.

So yeah, he's a little stressed.

>> If that's fine with you, then it's fine with me.

I don't really care, as long as it works.

>> If you want to cut it, I guess we can cut it.

>> Is that going to give you enough space to weld?

>> Yeah, it looks good.

>> All right, that's not going anywhere.

Great job, Lindsey.

>> What are you welding?

>> Pump.

I'm actually going to weld this to this, and I'm going to weld this onto that.

Because this is going to go onto the pump, so as this turns, it turns the pump, and therefore pumps the water up.

That's how you weld.

Great.

It's going good.

Now we've got a sprocket on a pump to move the water.

>> Let me see.

Let me admire your work.

Okay, so we're good with this.

>> We just need to mount it to the bike.

We just need something to keep it there while we test it.

>> There you go.

>> Awesome.

>> Now I've got to drill holes in the wheel so that I can attach the cups.

Okay.

How beautiful.

>> Here.

Come over here.

How many of those can you make?

>> I made 12.

>> Can you put them all on here?

>> You want me to put them all on there?

>> Yeah.

>> Okay.

>> How many holes did you drill on here?

>> I drilled... (speaking Spanish) Like, in between each of these I put one.

>> (speaking Spanish) I'm sorry, man.

When I get stressed my Spanish comes out.

>> This is the escapement.

>> Okay, so this is the water mill.

It's done.

>> That looks cool.

How heavy is it?

Yeah, it's heavy, but it's balanced.

>> Put it on, put it on.

>> Okay, close it.

Yeah, close it.

>> It has to be perfect, guys.

I don't want to blow this thing, I don't want to have it be screwed up.

>> Right there?

Okay, don't move it.

Do not move it.

>> Wait, wait, wait.

>> Hold it, Ana.

>> I'm holding it.

>> Oh, you mean put this one there.

Is it on tight?

>> It's tight.

>> That's perfect.

>> I'm going to hold it.

Get the welder and weld it.

>> Are you kidding me?

>> No.

No joke, go.

>> Okay, perfect.

>> It's pretty lined up, man.

>> We've got quite a storm coming.

>> I know.

Good thing we have this tent.

Sweet.

The escapement is attached.

>> That looks really good.

Good work.

>> How's it going up, there, Zach?

>> We're going to put a tube right... >> What, like... >> Like that.

>> Yeah, that'll work.

>> Let's do the pump.

You want to pedal?

>> That's a long hose.

>> That's going to take a lot of pedaling.

Is the valve open?

>> Yeah, the valve's open.

>> Is there water going?

>> Yes, there is.

>> Yay!

It's filling up cups.

>> Yay!

>> Let's give it a try.

>> All right.

You guys ready to see this thing go?

>> Yeah.

>> Let's do it.

>> Okay, I'm going to pedal backwards to make the weight go up.

So, weight's going up.

There goes the weight.

Ready?

Look, it's turning!

>> Oh, very nice.

>> Yo.

>> That's really nice, guys.

>> That's good, guys.

Nice work.

>> Nice job, Green Team.

>> All right, guys, I think we did pretty well.

What do you guys think?

>> Yeah, it works.

>> I just want a hug.

>> I roasted the pigs last night in our smokers.

Now we're going to finish the off on the teams' rotisseries.

Let's see how they do.

Here we go.

I think I can get the hang of it.

Oh, good.

Old school, the grandfather clock.

I love it.

That's great.

Boy, I love these ideas.

It's working.

It's not smooth, but it's consistently turning, and that's what counts.

Beats pulling it by hand.

I want to give this pig the taste test now.

Mmm.

Yeah.

That's some good pig.

I'm cooked.

Think I should have gone into training for this.

This might make me go vegetarian.

Here we go.

Wow, look at that.

>> Hey, it works.

>> Yeah.

>> I love it.

The pig is looking good.

Wow.

Passes the taste test.

Uh-oh.

Wait a minute.

I guess it ran out of water.

Let's start pumping again.

>> Hey, Rob.

How's it going?

>> Good, how are you, guys?

>> Hey, Rob.

>> How do you like the Green Team's design?

>> I like it.

Nice, steady rhythm.

It was a little clunky, but it kept turning.

That was the key.

>> So that works sort of like a grandfather clock.

>> It seemed to work.

>> Like clockwork?

>> I liked it.

Yeah, like clockwork.

>> If you want something for the masses, something that's entertaining, this is the one for you.

I mean, don't get me wrong.

I know how endlessly entertaining it is to watch a clock do this.

If only water wasn't entertaining, Niagra Falls would have broken down a while back.

>> I get that, yeah.

The water and fire combination, they go together.

>> Exactly, man.

>> Very different from the other design, but a great inspiration as well.

>> Why don't we go over there and huddle up and talk about which one really works the best?

>> Thanks, Rob.

Appreciate it.

>> Thanks, guys.

Bye, Rob.

>> I love them both.

I mean, they were both inspirational.

>> Both designs were awesome.

They were definitely awesome.

I just think ours is better, that's all.

>> He seemed to really like it.

It was fluid without all the fluid, you know?

>> Oh!

Juan bashed on ours more than he bragged about his.

>> I like my marketing.

>> I like your marketing, too.

Niagra Falls right there, that was clever.

>> Here they come.

>> Good, I'm starving.

>> Design Squads, Rob has come to a decision.

>> I want to thank you guys first and foremost, because you came up with some great ideas here.

Green Team, you came up with a seriously functional unit here.

The pendulum idea, it's a great one.

I wish you had put the face of a clock to add a little bit of spectacle to it.

Purple Team, you guys got the spectacle down.

I love the water.

I love that bike seat, too.

Thanks for thinking of me.

Because I had to work that bike.

Matter of fact, I had to work it a little too much.

But I think the idea was a good one.

If I had to cook that pig again, though, I'd have to say I'd have to go with the Green Team.

It's a little bit easier, and that counts for a lot when you're cooking a pig.

Thanks very much, guys.

>> Thank you, Rob.

>> So 100 points goes to each member of Green Team, which puts us in an interesting situation.

Going into the final challenge, we have a three-way tie for second.

Obviously, folks, Wes is in the lead.

>> Now, our three-way tie is between Annelise, Lindsey, and Juan.

So we're going to have to have some kind of tiebreaker.

We'll worry about that later.

For now, let's eat some barbecue.

>> Yeah.

>> If I would have won, I would have tied Wes, and that would have been the end of it.

We lost, so I tied you two, and that's the end of it.

>> Lindsey and I think that our team worked really hard and came up with a good design and executed well.

>> And we sold it without bashing yours.

>> It was a marketing strategy.

>> Why didn't you just sell yours?

>> That's because there wasn't that much to sell about it.

It doesn't work as well as ours.

>> And you wouldn't take that as bashing?

>> Well, she's bashing you now.

>> I think Lindsey and I are just glad to be here.

We came from last place together, so it's nice not to be on the bottom anymore.

>> It's been a really long journey.

>> I just want to see what they come up with for the tiebreaker.

I'm excited.

Bring it on.

>> May the best engineer win.

>> There you go.

>> Wow, that's nice.

>> So will it be Juan, Lindsey, or Annelise who will face off against Wes in the final challenge for the Intel scholarship?

>> Hey, Lindsey, there's so much more action on our Web site.

>> Yeah, behind-the-scenes stuff like our blogs.

>> Not to mention you can watch full episodes.

>> Play games and build cool projects.

>> Awesome.

Let's go to pbskidsgo.org.

>> Coming up... >> Your tiebreaker challenge is to build a kite.

>> It's all or nothing.

>> Oh!

>> Your clients have come to a deci Captioned by Media Access Group at WGBH access.wgbh.org >> We are PBS.