- Are you feeling curious?

- I think so.

- Today on Curious Crew, starting to spin, we set sail on an investigation.

Wow.

Of wind power.

It's gone with the wind.

- [Announcer] Support for Curious Crew is provided by MSU Federal Credit Union.

From sweet peace to teens, MSUFCU offers you accounts that grow with children.

With financial education, gaming apps and events, MSUFSU provides the tools and resources to make learning about finances, fun and interactive.

Also by the Consumer's 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.

(upbeat music) - Hi, I'm Rob Stevenson.

And this is-- - Curious Crew.

- Welcome to the show, everybody.

We always like to start every episode with a couple of discrepant events because discrepant events simulate-- - Curiosity.

- That's exactly right.

And I've got a fun one for you to start with, and I'm gonna direct your attention right over here to this white fan.

Now in front of this fan, I've got a weighted box.

Now I'm gonna turn on the fan controlled with a foot pedal, but then I'm going to place this dowel with this four inch piece of ribbon in between the fan and the box.

And I want you to watch closely to observe how it behaves.

Okay.

So we get the fan going.

So Carmela, what are you noticing about the behavior of the yarn here?

- It looks like the wind from the fan is pointing the yarn toward the box.

- Okay.

That's a very good observation.

That's exactly right.

Now, Nash, what would happen if I move the yarn and put it behind the box?

- I think the yarn is gonna stop moving with the wind.

- Okay.

Let's put it back there and see what it does.

Now this is where it gets kind of perplexing because it seems like if it's behind the box, it seems like it should stop moving, doesn't it?

Now I'm gonna move it even further away from the box and see how it behaves out here.

Interesting.

We'll set that aside for a minute.

And you might notice, I've got a huge table fan here and on top of the table fan, we've got this cylinder made of acetate and it's held together with embroidery hoops.

Now I'm gonna turn this fan on high.

And what we're gonna do is take several different objects and put them into that wind column just to see what they do.

Okay.

Let's start with a styrofoam ball.

Let's see what this does.

Woo.

That's kinda cool.

Sort of hovering along there.

Oh, it's climbing.

I'm gonna put something else in here.

How about this big cluster of feathers?

What might this do?

Let's take a look.

Oh, that ball's going.

Oh no.

It's gone with the wind.

No.

Okay.

Let's put in these feathers, see what it does.

Oh yeah.

Oh, that one quickly.

Now I'd like to try this.

A balloon with a really long string and it's kind of like a practice golf ball at the bottom.

Let's see how this behaves.

Isn't that fun?

Sort of stuck there.

Okay.

I'm gonna try this.

This is a really strange one too.

I've got a piece of paper that I folded and then cut.

And I've got some paper clips on the bottom part here that's wrapped in tape.

Let's see what this does.

Let me put it in.

- Whoa!

- Whoa!

It's spinning.

- It looks like a helicopter.

- Oh, it looks like a helicopter.

We've got some interesting discrepant events here.

And I want you guys to be thinking about this.

I'm gonna invite three of you to do a little scientific modeling.

See if you can come up with some explanations for these phenomena by the end of the show.

So who wants to do a little modeling moment today?

Okay.

How about Ali, Kah'Reice and Callen?

You three are gonna do that.

Now does anybody have a guess what we're gonna be talking about today?

What do you guys think?

Julia's got a guess.

What do you think Julia?

- Wind.

- Wind.

That's excellent.

We're talking wind power today.

I don't know what gave that away.

Stick around, this episode, sure to blow you away.

(upbeat music) - Did you notice that the yarn fluttered differently on both sides of the box?

It's weird, that it's still fluttered, even when it was behind it.

- I noticed that too.

I also noticed that the flutter changed depending on how close it was to the box.

- The one column reminded me of people doing indoor skydiving tricks.

They get into this giant tunnel and float around.

- Yeah, that would be fun.

Maybe we could get Dr.

Rob to make a bigger one.

(upbeat music) - Wind is an interesting weather phenomenon.

Imagine standing outside on a windy day and the wind is blowing toward you then suddenly the wind blows harder from a different direction?

Wind is the movement of air.

It might be a gentle breeze, which is wonderful on a hot day, or be high winds, which can become destructive.

No matter the wind's strength or direction, wind is the result of gas is moving from higher to lower pressure areas.

The greater the temperature difference, the faster the rush of air or wind.

Now that's a nice breeze.

(upbeat music) Weren't those discrepant events interesting you guys?

- Yeah.

- Yeah.

- Now I've got a fun little device that I'd like to share with you.

I'm gonna get this fan going, and I want you to take a look at the device in front of me, 'cause it's gonna start to move.

Now Nash, how might this be used in weather?

- I think you can use that to measure the speed of wind.

- You actually can use this to measure the speed of wind.

This is called an anemometer, which is kind of a fun word to say.

Anemometer.

Now, when you look at my anemometer, Carmela, what do you notice about it?

- I notice that one of the cups is red and all of the other ones are blue.

- Okay.

That's a really important part of an anemometer.

We wanna distinguish one cup from the other three.

And here's why.

When we're trying to figure out the speed of the wind, we want something to rotate.

And if we can calculate how many times it rotates, we can convert that to wind speed.

Now, if these were all blue, it would be really hard to keep track.

Wait, was that the one I was counting?

Oh no, maybe it was that one.

And of course you're also noticing that they're cupped because that will catch those air particles and deflect them off and get the whole thing rotated.

Now a lot of weather stations, meteorologists use anemometers but most of those are gonna be digital or electronic.

Mine is just going to sit by itself and I need to count and calculate.

Now you guys have some too.

Carmela, what are yours made of?

- Paper cups and straws.

And one of the cups is covered in tape.

- Oh good.

So you can count the one covered in tape.

Excellent.

Now I know you're gonna be using some hair dryers to get them going.

I'm gonna ask you to count how many rotations you get in a 10 second period.

And based upon the number of revolutions, we're going to calculate your wind speed using my table.

So are you guys ready?

- Yeah.

- So once you get your hair dryers going, I'll start my timer and you'll be able to start your count.

Let's fire them up.

3, 2, 1.

And that's your end.

Okay.

How many revolutions did yours have, Nash?

- Mine had 34.

- 34.

Okay.

According to my chart at 34, that's going at about 12 miles per hour.

That's really fast.

Oh my goodness.

Okay.

And how about you Carmela?

How fast, how many rotations did you get?

- Mine had 20.

- 20.

That time.

Okay.

So coming in at 20, that's going to be seven miles per hour.

You've got some fast hair dryers there.

Now this is a really interesting thing to do outside.

So taking your anemometer outside and getting a sense of how fast the wind is blowing is really interesting.

Now you might be wondering, Dr.

Rob, why is there a range of revolutions on your grid there?

Which kind of makes sense.

A hair dryer or a fan is consistently blowing, but the wind isn't consistent.

It picks up, it falls back.

And so we usually have a range where we're trying to figure out how fast the wind is blowing.

Now I do in fact, have a digital anemometer, and I'm gonna show you this one next.

I'm gonna turn this on and I'm gonna place it within the line of the fan itself.

And of course, once this is going, this is really quick.

That was going at about 6.3 miles per hour.

Now, of course, whenever you're gonna be flying a kite, using a drone or going sailing, a digital anemometer can be really useful.

I would encourage you to try making your own anemometer, and you can measure the wind speeds where you live.

As the sun heats up the Earth's surface gas particles in the air contact the ground, warm up and move more quickly.

Warmer particles move faster, spread out and are less dense.

So the warmer air rises pushing through colder particles.

The Earth's surface doesn't warm up evenly though.

Areas with more direct sunlight like the equator are warmer than the poles that receive indirect light.

Sand may warm up more than mountain rocks and the water is cooler than land.

Such uneven surface heating makes warmer air regions rise and cooler regions sink.

And the result is wind.

(upbeat music) So we've seen how wind develops and even how to measure the wind.

But now let's switch gears a little bit and think about how we can harness wind power to do work.

So I wanna start off by sharing with you this little windmill I made.

Kah'Reice, do you have a guess what I used for these little blades, the sails?

Can you tell what I used?

- It looks like you used miniature paper cups.

- You're totally right.

What I did is I took some scissors and I just cut it in half and then I cut it in half again.

So down in quarters and just cut off the base.

And so then I have a nice curved surface that can catch the air particles from my fan.

Now behind the wind turbine itself, you're gonna see there's a little motor.

Now normally when you see a motor, you're probably thinking, oh, Dr.

Rob's gonna hook up a battery and he is gonna make the thing spin, but I'm not going to because I'm gonna use wind power to make it spin.

So here's my wondering.

Julia, if I spin the turbine, what do you think might happen with the energy going this direction?

- I think it's going to produce electricity.

- I think you might be right.

And in fact, I've even hooked this up to a little multi-meter here.

And what we're gonna do is because this is a very small motor, one and a half volts, I'm gonna measure this in millivolts.

And what we're gonna look for is do we see any electricity being converted from our wind power?

Let's take a look.

There it goes.

It's starting to spin.

And if we look at that multi meter, we can see those numbers starting to show up because we are actually producing electricity.

Isn't that amazing?

Now windmills have been around for a very long time.

They've been used for things like grinding grain or cutting wood or pumping water and even more recently, for electricity.

But I've given you guys another challenge.

If we can make another windmill that's just using wind power to convert it to mechanical energy, can we come up with a way that we can wind up a paperclip on a string using wind power?

So here's what I've got.

There it goes.

Whoa, it's flying around.

Oh my goodness.

Yeah, that wound up really, really fast.

How about that?

Now I know you guys each have one.

Julia, what does your design look like?

- Mine is a paper pinwheel.

- Oh, okay.

Now can you blow into that so we can see it work?

(soft music) Oh yeah.

It's totally winding up that paperclip.

Nice job using your own wind power there.

So Kah'Reice, let's look at your design there.

Now, what did you make your blades out of?

- I made my blades out of aluminum pants.

- Oh, awesome.

Okay.

Now let's see if yours works.

Oh my gosh.

That goes really, really fast.

You can see that windmills come in a lot of different shapes and a lot of different designs, but the one thing they have in common, they can turn that wind power into mechanical energy and sometimes, even electrical energy.

When gas particles heat up, they spread out and this is described as low pressure.

Cooler gas particles don't move as fast.

So they tend to be closer together, which is described as high pressure.

As warmer, low pressure areas rise, space opens up for the colder particles in the high pressure area to fill in.

The high pressure particles will always fill in that extra space left by a low pressure area.

That particle movement is the wind, and the direction is toward the low pressure region.

Those moving particles that make up wind have energy that can be measured or even used to power different devices.

(upbeat music) You're gonna notice I have here a potato, or you might call it the potato.

- My favorite investigation would probably be the one where we tried to balance a potato.

- We are going to try to somehow come up with a sculpture so that the entire thing remains balanced.

- Just being able to see how the potato just seemed to kinda levitate, was really fun to do.

- We did it!

- There's no reason this should be able to work and yet it's working.

- [Announcer] Stem Challenge - So have you had fun exploring wind power so far, you guys?

- Yeah.

- Yeah.

- Now I hope you got your second wind because I've got quite the Stem Challenge for you today.

You are going to be making your own wind car, a car that can roll under the power of wind.

Now I know you've got your materials.

Are you guys all ready to start your builds?

- Yeah.

- Yeah.

- All right, let's do it.

- Dr.

Rob has us making these little wind cars, which are kind of like sailboats, but cars.

- I have wooden wheels and wooden sticks to add the sails to.

- I'm using a sponge and some dowels and straws and tape.

I'm having the hardest time taping anything to the sponge.

- The last bit of tape on.

The hardest part was connecting the wool sail to the dowels.

The wool didn't like to sit still for me.

I think I got the optimal sail angle now.

- Let's take a look at each one of these.

Carmela, tell us a little bit about your wind car.

- My wind car has two sails at the top, so then they both get pushed the same direction by the wind, which makes it move.

- Let's give yours a whirl 'cause I think you've got a hair dryer ready.

Let's see how it moves.

Oh wow.

Yeah.

That one really caught some wind, flew right off of her workspace.

I would say that was a very effective wind car.

Okay.

Nash, what can you tell us about yours?

- My wind car is a single sail car with, what kind of looks like the bottom of a boat and a little blue car with little black wheel and axles with a big green and black wool sail.

- Okay.

Nash.

Let's give yours a try there.

See how it does.

- Here we go.

- Wow.

Another very successful design.

Good job.

And Julia, you have the perfect space to test yours.

Tell us what did you do with your wind car there?

- My car is made out of plastic wheels and a sponge and then it has the, the sail is made out of belt.

- All right, let's give it a whirl.

Let's see how it does on the floor there.

Wow.

That one caught a lot of wind, lifted up the whole back end.

That was very exciting.

Nice job.

Sure as the wind blows, those were some pretty clever designs, you guys.

Try making your own wind car.

You can try it inside like they did with a hair dryer or a fan or even better, take it outside and let the wind do its work.

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

Hi, I'm Janellyn.

And today I'm with professional skydiving instructor, Erendira Sanchez Gonzalez.

Erendira, tell me where you are and what you do.

- I'm in Houston at Skydive Spaceland.

Also I'm a skydiving instructor.

- How is stem incorporated into your job?

- It's really important to know the science about the winds and understand that for you to have a good skydive.

When we jump out from the plane, we use the relative wind for jumping out.

What position you have when you jump out is how fast you're gonna free fall.

- I heard you've done more skydive jumps than any other woman in Mexico.

- That's right.

I have 15,000 skydive.

Have you ever skydive?

- I have not skydived before, but I would love to.

Erendira Sanchez Gonzalez and I go right into the science of skydiving.

Explore your possibilities.

(upbeat music) And now back to Curious Crew.

(soft music) - So we're gonna have a little sailing lesson on the SS Curious Crew.

Now Callen, I got a question for you.

Have you ever heard of the expression sailing down wind?

And if so, what does that mean?

- It means when the wind is coming from behind your sail and pushing your boat forward.

- Exactly right.

And so here I have a little model boat that's just sitting on wheels and you'll notice I've got a square sail.

I'm gonna turn on the fan for just one second and we're gonna run this downwind.

Now this is a pretty effective design and square rig sailboats have been around for an incredibly long time.

There is a problem with this design however.

Let's imagine I try to turn the boat around.

I'm gonna try to go this direction.

Now watch what happens in the square rig sail.

Oh, oh.

That's a problem.

Now engineers are clever people.

And so it didn't take long to start coming up with new sail designs.

So take a look at this one.

And of course with a wonderful, Curious Crew logo on there to be sure.

And let's start off just by going down wind again.

So we've got that moving nicely.

This sail design is a little bit more versatile.

You remember what happened when I tried to turn the other boat around?

I went backwards, didn't I?

So let's see what happens if we go perpendicular to the wind with a triangular sail.

Oh, no problem.

Still going forward.

Now Ollie, do you think I might be able to turn it even a little bit more up into the wind?

- I think so.

- I like how you are predicting with a question mark.

So now I'm gonna haul in the sail a little bit more and turn it a little closer to being up into the wind.

Ah, there we go.

And off we go.

Why can that work?

If we can get the air particles to go behind the sail, as well as on the front side of the sail, we have the sail and the mask pushing on the particles.

The particles are pushing back, but because the sail can curve, a lot of those particles deflect off.

So we actually have more forward push and we're able to sail up into the wind, which seems really, really strange.

Sail design is really important in sailing, but sail design is also really important in wind turbines.

Take a look at this model.

I'm gonna turn this sideways.

We can see the blades, but I want you to see what's going on behind the blades.

Callen, do you recognize what this is back here?

- It's a gear box.

- And Ollie, can you tell how many gear ratios I can do here?

- Three- - You're right, cause I have three pairs of gears.

Now, if we can maximize wind power, the wind can cause the sails or the blades to turn, it will turn an axle which will fire up this generator and actually produce electricity.

I've got it set up right now in a one to three gear ratio.

I'm just gonna use my hand to rotate it around, but I'm not seeing any light from that bulb.

I'm gonna change the gear ratio.

We're gonna go a one to one ratio.

Now this is called direct drive.

This is a little harder for me to push, but let's see.

Oh, I'm starting to see some light.

Do you guys see some light going on there?

What would happen if we then change the ratio to a three to one?

This is gonna be a little harder to push.

Oh my gosh.

But the light comes right on.

Wasn't that interesting, you guys?

- Yeah.

- Yeah.

(soft music) - When we saw the sail car, I started thinking about the yarn.

We know that the wind can deflect around objects.

So maybe that's what happens with the box.

- Right.

And the yarn is like the tell tales on both that show the direction of wind.

The box interferes and changes the direction of the wind.

- That makes sense.

Those objects in the wind column move differently depending on their shapes and masses, and the blades in the helicopter, deflected the air particles, causing it to spin in the column.

- So have you had fun exploring wind power today, you guys?

- Yeah.

- Yeah.

- That's excellent.

Now I know you've been thinking a lot about these phenomena from the beginning of the show, and what can you tell me about this fluttering yarn, Kah'Reice?

- We think air particles hit the box and collide with other air particles causing the yarn to flutter behind the box.

- Let's look at this.

I'm gonna turn this on again.

So we saw at the beginning, this flow was nicely moving the yarn right towards the box here.

This is called a laminar flow.

It's just steady.

Now as soon as we move it behind, it seems like it should stop.

However, just as Kah'Reice was talking about, there are particles that are bouncing off the box, colliding with other particles and beginning to swirl around the box.

We can see that swirling motion directly with the yarn itself.

Now if I move it even further away, we get that laminar flow again.

Okay.

What have you guys figured out about this wind column, Callen?

- We know that band blades are pushing air particles through the column, but different objects reg differently, depending on their shapes sizes and densities.

- Yeah.

The paper helicopter was really interesting to me.

When it fell, the two sails were hit by air particles, but they pushed the sails in different directions, which means that it spun.

- I gotta let you in on a little secret.

When I first made the helicopter, I had the blades a lot longer, and when I put it in the wind column, it went flying right out through the top.

The shapes, the densities make a big difference.

And of course, when we use a balloon like this, I wanted to use a nice long string.

Cause I could use the mass of the ball to really keep it in the column, but we could use the lift or the buoyancy of the balloon to keep it above the column, which makes it really interesting.

And then of course, we have things like this, that hover around and then scoot right out the top.

So our wind tunnel is pretty impressive, but they make wind tunnels that are a lot bigger.

In fact, big enough for a person to get inside.

I don't know if you've ever seen the ones where we've got indoor skydiving, where a person can go in there with giant fans.

Those are actually really great for astronaut preparation before they're going into outer space.

So looks like it's time for us to go like the wind.

So remember my friends... - Stay curious.

- And keep experimenting.

Get your curiosity guide and see more programs at wkar.org.

- [Announcer] Support for Curious Crew is provided by MSU Federal Credit Union.

From sweet peace to teens, MSUFCU offers you accounts that go with children.

With financial education, gaming apps and events, MSUFCU provides the tools and resources to make learning about finances, fun and interactive.

Also by the Consumer's 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.

- We're making sail when the boat car... No, we're not.

- It's gonna get noisy.

- Let's start the count.

(laughing) He's doing donuts now.

(laughing) (upbeat music)