01x10 - Air

[bunniefuu]

Today, DFTD will shale by the Statue of

Liberty. Wow, I sure feel a lot of wind.

OK, Captain, turn around. To meet the

teenies behind the Super Soaker. The most

powerful water g*n in the world. Let's

go. Make a balloon ride up to 8000 feet.

It's hot. Kelly. And

back down again.

Major funding for Dragonfly TV is

provided by. Best Buy

We're excited to see kids like you

exploring the world of science and

technology, because what you're learning

is going to change the way we live. Best

Buy The future looks fun.

And by the National Science Foundation,

supporting education and research in

science, mathematics and technology.

The National Science Foundation,

America's investment in the future.

Additional funding is provided by the

Donald Wiesner Charitable Trust

Foundation.

On today's

show, we'll be looking at air. Now you

may be wondering how we're going to do

that. Yep, air can be hard to see. But

today, we're putting it center stage.

Think of the wind. You can feel the air,

even though you can't see it. Science can

coax air out of high heat. So today,

we'll check out the power of a super

soaker and cruising a hot air balloon.

But first, we're headed to New York City.

Where Wheaton fills both tall sails...

And small sails. Job h*! Wind

sails are never... Got it. No, I'm gonna

win this. No, you're not. Yes, I am.

I can't believe she just passed me.

I won. Just barely. Hello, I'm Emmanuel.

Hi, I'm Fiji. I love sailing. I sit here

all the time. Yeah, the model boats use

the winds to move, just like real

sailboats. Yep, the little sails catch

wind and away they go. We can control the

sails and position them with these

remotes. Watch them go.

When we're racing, we realize that the

boats go faster in certain directions to

the wind. We want to figure out which way

is the fastest. So today,

we're testing our boats to see which

angles the boats go the fastest into the

wind. We're going to try three different

positions. The first is directly with the

wind. Sailors call that running. If the

wind blows this direction, then the sails

look like this, and the boat goes with

the wind. We have a race course on our

pond with buoys as the marker. We'll time

how long it takes to get from one buoy to

the next for each direction. Since we

know that the buoys are 10 meters apart,

we can figure out the speed by how long

it takes to get from buoy A to buoy B.

Okay, I'll control the boat, and you time

how long it takes to get from one buoy to

the next. Okay. Ready, set, go.

Go, go, go. Stop.



Running with the wind?Got it.

Next, let's try sailing broad reach.

That's sailing with the wind again. Is

that at an angle?Right, like this.

The boat's lined up. Ready to time it?

Already. Ready,

set, go.



I wonder why. Let's try our last race

before we try to figure that out. Okay,

into the wind. Sailing clothes haul when

the sails are kept close to the boat, and

the boat moves into wind at an angle,

like this. The boat's lined up. Ready,

set, go. Here we go again.

Wow, 42 seconds. That was slightly faster

than running. I would have never guessed

that would go as fast into the wind. All

right, let's check our results.

Sailing with the wind or running took

about 45 seconds. And sailing broad

reach took about 30 seconds. That was the

fastest. Sailing close haul was about 42

seconds, slightly faster than running. So

broad reach was the fastest. It seems

like the sails caught the most wind that

way. But the boat is moving on an angle

to the wind. I just learned about

Bernoulli's principle at school. I wonder

if it has to do with that. What's

Bernoulli's principle?Take

this piece of paper and blow over the

top. See how it

rises?The air that's moving fast over the

top is creating a low pressure area. The

air below is at a high pressure, which is

making the paper move up. That's probably

what's happening to the sails. Maybe. I

wonder if we could measure the wind on

either side of the sail. Let's see if

it's going faster on one side or the

other. We could, but the models, they're

pretty small. Yeah. We're gonna need a

bigger boat. No, a bigger boat. No, a

bigger boat. No, a bigger boat.

Okay, sit tight, and we'll catch up with

Gigi and Emmanuel at the end of our show.

But first, let's deal with Bernoulli.

Bernoulli. Bernoulli?I've

heard this name a lot. He's the

mathematician dude who figured out how

air moves around wings, sails, and kites.

So are you as clever as Bernoulli?Let's

find out and test your know-how. Told

you not to drive that way Now you're

gonna have to pay

If something huge falls over, it's pretty

hard to pick up, right?RightSo today's

question is, how do you use air to pick

up a giant semi that's tipped over?Got

any ideas?Later, we'll give you an answer

that might lift you out of your seat.

It's real. Air is

invisible, so how do you know if it's

really there?Have an adult light a

candle. Find an empty salt carton,

a plastic sandwich bag,and a rubber band.

Carefully remove the metal spout from the

salt carton and cut the bottom out.

Stretch the plastic bag over it. Use the

rubber band to hold it in place so it

looks like a drum. Aim the solid at the

candle and tap the plastic bag from

behind. Whoa, look at that.

Air is made of real stuff, which means

you can push it around. When you tap the

plastic bag, you push the air inside the

carton so it squirts out the spout. Air

moves to the flame and blows it out. Try

to see how far away you can be and still

blow the candle out.

What instrument measures air pressure?

Thermometer, altimeter, barometer.

Barometer.

Hey, down here. Hi, my name is Patsy.

And I'm Masha, and we're at the Snowmass

Hot Air Balloon Festival in Colorado.

The balloons are so big. Some of them are

five stories high. You can fit a whole

house inside a balloon. We want to know

how you get something the size of a

building up in the air.

First, Masha and Patrick try to find out

everything they can about hot air

balloons. The balloons are made of

nylon, and it's all different colors.

You can't blow a hot air balloon up like

a regular balloon. So a pilot uses

normal air around it and blows it into

the balloon with sand. As the

heated air goes inside the balloon,

the balloon gets rounder and rounder and

bigger. How much does the balloon

weigh?750 pounds. That's

what I heard. All this can be lifted by

just hot air.

Masha and Patsy can't stand around

watching forever, so they decide to jump

in and start gathering data.

I'm actually in the dashboard of a hot

air balloon. This is our

pilot, Joel. He's going to have to give

us a safety talk. Be very careful not to

kick this little latch down here because

that secures the trap door. If you kick

it, it'll fall down.

Masha and Patsy want to find out how the

temperature of the air inside the balloon

affects how fast it goes up or down.

Let's go fire those burners! It's

hot! Really hot!

Yeah!

We need to see how fast we go up and down

in the balloon. Joel said we could use

his variometer to do this. That way we

can measure feet per minute, just like

mph in a car. It's called

ascending if you're going up or

descending if you're going down. But how

can they tell exactly how hot the balloon

is?You see this white wire here?Yeah, it

goes all the way up to the top. There's

one of these little sensors up there like

like this one here. Oh, so that's the

temperature at the top.

Using the handy instruments, Masha and

Patsy keep track of two things. The

temperature inside the balloon. 217

degrees Fahrenheit. And how fast the

balloon is going up or down.

Perfect! We're in the water!

This is so cool. I mean, it actually

floats.

To divide up the work,When we are higher,

I'm going to record the numbers. And when

we're low, Masha's going to record the

numbers. We'll go all the way up to 600

feet.

That's 200. 2 is 200, 4 is





degrees. 203. But here's the

feet per minute.

Hot air rises, so it's obvious that the

balloon should rise when the temperature

inside the envelope is a

significant amount hotter than the

temperature of the outside air. Where did

you learn that?I paid attention in

science class. Oh, OK.

What goes up must come down.

Now, Masha and Patsy take the raw data

they collected and try to figure out what

it all means. And finish off the dance.

We're taking the information we got on

the balloon. I'm putting it onto a chart

with blue stickers for lower altitude

data and red stickers for higher altitude

data. On Patsy and Masha's chart, the

farther the dots were above the line, the

faster the balloon was going up. The

farther below the line, the faster it was

going down. The farther a dot is to the

right, the hotter it was inside the

balloon. Masha and Patsy try to see

how each dot matches a part of their

balloon ride. Look, see this one?

Descending slow, it took up the most

heat. Yeah. And hovering does

also, especially hovering at high

altitudes. Then they look at patterns in

the chart that'll tell them what they

really want to know.

I get it. The higher the temperature in

the balloon, the faster we went up.

These are the dots at the top of the

chart. We also need a high temperature to

go down slowly because we need to

control the balloon so we won't drop down

like a rock and the hovering. It's very

interesting how they have a full range of

temperatures here. Same here. Look at it.

We don't have enough information here to

draw a conclusion. We need to factor in a

lot of things, like the size of the

envelope, the size of the basket, and

even how many people are in the basket.

So how are they going to find answers to

their new questions?Let's go gather more

information!

What a gas. Turn on the heat and up you

go. Yeah, but what I didn't realize is

you have to keep heating the balloon in

order for it to hover in one place. Think

of this ball as a hot air balloon. It's

lighter than the water around it, so it

floats. Now the balloon is full of hot

air and is lighter than the cooler air

around it, so it floats on the cold air.

Yeah, but it's only lighter than the

surrounding air if you keep it hot. OK,

the hot air balloon mystery is solved.

What mysteries of science have you tested?

Surf on over to the Dragonfly TV website.

It's at PBS online at pbskids.org.

Once you get there, tell us what

questions you're investigating and what

you find out. Or you can write us at

Dragonfly TV, 172 E 4th St. St.

Paul, MN 55101. We want to hear from

you. Time to crunch your brain.

Have you guessed how air can get a flip

semi back on the road?We'll tell you how

at the end of the show, but first, Ashley

and Chloe have some ideas of their own.

How about using the wind to lift it?

Yeah, when you fly a kite, it pulls

pretty hard. That would

have to be a really big kite to pull off

this truck. What else can we do with air?

Hmm, I know the air holds up the

inflatable roof where I play tennis.

Let's experiment with that. Okay.

I taped up this fake to make it look like

a balloon. Then I poke this straw in so

that way I can blow it up. Let's see

if you've got enough lung power to lift

me.

I'm blowing as hard as I can, but why

isn't lifting you up?Only part of the bag

is pushing the seat. Let's get a bigger

seat.

Go for it, Ashley.

It's working. It's working.

With a bigger board, I didn't know how to

blow it hard.

Do you think this would work on a bigsemi?

Once Ashley got the bag full of air, she

could support Chloe without blowing hard

at all. All she'd have to do is put a

little pressure on the straw. It looks

like we just gave him a huge hit,

Michael. Stay tuned for the answer later

in the show.

Let's go! I'm Lonnie Johnson, and I'm an

engineer and an inventor.

When I came up with the idea for Super

Soaker, I was experimenting in my

bathroom with a high-pressure water

nozzle.

And the stream of water was so powerful

that I looked at it and I thought to

myself, geez, this would really make a

neat water g*n.

Ever since I was a small child, I've

always tinkered and invented things.

And even before I knew what an engineer

was, I knew I wanted to be someone who

built things and designed things.

An engineer is someone who uses

mathematical principles and physics to

figure out how to make things work. What

I'm holding in my hand here is the very

first super soaker that ever existed.

This is a handmade model. The bottle here

was actually a plastic bottle that you

like for soda pop. This is PVC pipe that

you can get at a hardware store.

And this is a model that's made through

mass manufacturing in a in a factory

where all the parts are molded. What's

most fun about my job is the

creativity, the opportunity to come up

with ideas and then see people

enjoying them. This g*n here is one of

the newer designs. It has a way of

sh**ting in both directions. You can

sh**t out the front through the pump, or

you can sh**t out the back through the

rear nozzle so you can get your

competitors going and coming. Being an

inventor and being an engineer is a very,

very good combination, because when I

have ideas about things that I want to

create, well, being an engineer, I'm able

to figure out how to make them work.

So remember, if your dream is to invent

something, if I can do it, you can do it,

too. I started with an experiment in my

bathroom, and I've ended up with the most

powerful water g*n in the world.

Now that's having fun with science and

engineering. Hey, Michael. Can I

see you?

Photo mess. I so got you.

Do I look wet to you?Inventors create a

lot of cool stuff. What ideas have you

come up with?Make sure you let us know.

We'll let you know how later.

What animal swallows air in order to

float on water?Pig,

armadillo, porcupine,

armadillo.

In the first part of our show, Gigi and

Emmanuel did some tests with the model's

hailboat. They found out that pointing

the boat with different angles to the

wind affects its speed. But now it's time

for the big ride in New York Harbor,

where the kids are sailing on a 40-foot

salute. Hey, everybody, come on Come

on, come on, come on, come on

Next stop, New York City,

America's hometown.

We're going to recreate our model test,

but on this real sailboat. And we're

going to find out which direction is the

fastest and see if our models match it.

Well, you don't notice much wind when you

travel with it. Right now, we're running

with the wind. Our speed is 4.7 knots.

Boat speed is measured in knots. It's

sort of like mph, but on a different

scale. The global positioning system

tells how fast the boat is going. Next,

let's try our rotaries, Captain Tom. OK,

coming about. Turn, turn, one,

turn.

Right now, we're sailing at an angle to

the wind. Sailing broad range sure spins

a lot faster. What's the knot meter say?

Seven knots. Wow, a lot

faster than running with the wind. Yeah.

Okay, captain, let's turn around and try

sailing close-up. Sailing,

sailing on the ocean. Wow, I sure feel a

lot of wind. Yeah, look at the wind

indicator approximately pointed straight

back. Yeah, but we're still only going at

six knots. And that's still not as fast

as Broadreach. We're still making good

progress, though. Yeah, so Broadreach was

the fastest. Yeah, I think we should sail

Broadreach again and measure the wind

speed on both sides of the sail. Captain,

Broadreach, please. Okay, coming rightup.

We're going to use a sneak tool called an

anemometer to measure the wind speed on

either side of the sail. We'll try to

measure any differences that might occur

around the sail.

What's the wind speed on the inside of

the sail?It's about two knots.

Okay, got it. What about the outside?It's

about seven knots. Wow, that's a big

difference. Yeah, let's go over our data.

Captain Tom, back to port. Okay. Coming

about.

When we sail with the wind, our speed

seems to be about five knots. We noticed

very little wind on the boat. And then

when we sailed toward the wind, our speed

was about six knots. A little bit faster

than sailing with it. And our fastest

speed was when we were sailing with the

wind, but at an angle. Our speed was

about seven knots. So broad reach was the

fastest, just like it was with the model

sailboat.

The different wind speeds on different

sides of the sail show that the Bernoulli

principle really did help make the boat

go faster. It's probably not as

important when sailing with the wind, but

the only way to find out is to go sailing

again. Captain Tom, come on. Captain

Tom, Captain Tom, Captain Tom.

We have to do some more testing. Come on,

babe.

reach is the way to go, thanks in part to

Mr. Bernoulli. The way air moves around a

sail actually helps us sail into the

wind. But now it's time for the answer to

today's question. How can air ride a

flipped semi-truck?

In fact, we do use air to lift even the

heaviest of trucks. By

inflating airbags, we can slowly right a

fallen truck.

The airbags are inflated to about 7

PSI. PSI means pounds per square

inch.





That means this bag can lift



itself. With just

a few of these, the truck goes right up.

Using less air pressure than you put in

your bike tires.

So when lifting, it's not just how much

air you use, but how much pressure and

how many square inches.

So a measly 7 pounds per square inch

lifts up a truck. Don't underestimate it.

Just three of those bags can lift 10 tons

of truck.

Wow. Keep your science ideas and

questions coming. We'd love to hear from

you. And it's one way we find all the

great kids you see on Dragonfly TV.

Here's the scoop. To find out more about

Dragonfly TV, head to PBS online at

pbskids.org. More experiments, Dragonfly

Magazine, teacher's guides, and a place

for you to send us your investments. Or

write us at Dragonfly TV, 172 East



Well, the air show has landed. Join us on

Terra Firma next time. For real kids,

real science, on Dragonfly TV. See you

soon. Dragonfly TV's all

excitement all season long.

Check out future episodes when we hang

with some Taekwondo black belts. We know

our Taekwondo moves pretty well.

Check us out and make the scream factor

on wild and crazy roller coaster rides.

It was scary. It was fun, though. That

one really got my heart racing. That was

great. And the last stop in the space is

some surprising food. We're cuckoo for

coconuts.

You're watching Dragonfly TV.

Major funding for Dragonfly TV is

provided by Best Buy.

We're excited to see kids like you

exploring the world of science and

technology, because what you're learning

is going to change the way we live. Best

Buy. The future looks fun.

And by the National Science Foundation,

supporting education and research in

science, mathematics, and technology.

The National Science Foundation,

America's investment in the future.

Additional funding is provided by the

Donald Wiesner Charitable Trust

Foundation.

One, two, three, four.

Shake that. Shake that. Shake that thing.

Shake that. Shake that. PBS Kids!

If you're a parent or teacher and you

want more ideas for great science

investigations,Check out our teacher's

guide and other publications. Write to us

for more info at Dragonfly TV, 172

E 4th St. St. Paul, MN