07x03 - Small is Different

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Dragonfly TV Nano is making huge

explosions, finding red and yellow

from silver and gold, and

playing Marco Polo with cells.

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the National Science Foundation,

supporting education and research across

all fields of science and engineering.

The National Science Foundation, where

discoveries begin.

It's Dragonfly TV, Dragonfly

TV.

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Dragonfly TV.

I'm Eric, and you're watching Dragonfly

TV Nano. Today I want to remind you that

small is beautiful. Now, some

kids want the biggest piece of pie, or

the tallest tree, or the widest flat

screen, but some stuff changes in cool

ways when it's broken up into the tiniest

of tiny nano-sized pieces. Here's an

example. Let's say that you've eaten your

giant burrito way too fast.

And you want help right away. Now, which

fizzy antacid would you go for?A whole

tablet or a crushed tablet?

Here are two whole fizzy tablets in this

glass and two crushed

fizzy tablets in this glass. Next

we take 2 measuring cups with water and

pour them in.

Instant replay, please. Instant replay.

Nope, I'm not playing a trick on you.

These tablets were identical, but one was

crushed into powder, so more of it came

into contact with the water and it

dissolved and fizzed much faster. Do you

know why?It's surface area. Shouldn't you

be in school?That's right,

the crush tablet had a lot more surface

area. Now

if you want to know how surface area

applies to cookies.

HmmAnushwa and Lara can explain

everything.

Hi, I'm Lara. And I'm Anushwa. And we're

crazy about cooking, especially baking.

So we're coming to you live. From the

Baking Lab. Of the Mill City Museum. In

Minneapolis, where the recipe of the day

is... Sugar cookies.

The Mill City Museum tells the story of

flour milling. It was also the site of a

huge flour expl*si*n in the late 1800s.

This is what cookie making would be like

a long time ago. The museum has

a really cool flour expl*si*n display, so

flour dust is not expl*sive when it's in

a bag or a cup if you get that flour

airborne. It increases the amount of

oxygen in between each one of the

particles, and it increases the surface

area. The surface area. And when you add

a spark, you get...

Boom. Time to make the cookies. First,

we'll mix all of our ingredients together

in a bowl to make the dough.

Next, we'll divide the dough in half.

Each person also gets one tablespoon of

sugar. And now for the fun part, a

friendly cooking challenge. Ready,

set... Roll.

It looks like we're

going in different approaches. Lara's

making lots of ba*ls to make small

cookies. I knew she was going with one

gigantic ball going with brute force.

That's weird. We both used all our sugar,

but I didn't even cover all my cookies.

What's up with that?We decided

to go to the Science Museum of Minnesota

to try and figure this out.

Oh, yeah. Full one.

We met up with Mahmoud, one of the

experts at the Science Museum, and he had

us do some math. Surface area. Surface

area is the total area on the outside of

a solid. He made us count all of the dots

on each side of a block of wood. There

were nine dots on each side and six

sides. Nine times six is 54.

Now, try it again. This time, break the

block apart. We counted six dots on each

small block, and 27 small blocks.



That's three times the amount of the

surface area of the baked block. But the

volume of the block stayed exactly the

same. That's kind of similar to what we

did this morning. We baked cookies, and

my cookie was really big, just like the

cube, altogether. But her cookies,

Laura's cookies, were little ones, just

like these tiny cubes. Mahmoud sent us to

the museum's big backyard, where they had

a cool soda expl*si*n kit. We've seen

a video of this experiment on the web.

You know the one, where guys add candied

bottles of soda to make these huge

geysers.

Hanushua and Lara are in for some

surprises. Now, this whole business of

surface area is pretty amazing. Take, for

instance, this sugar cube. The

surface area of this sugar cube is about



if we turn this sugar cube into

powdered sugar,

the surface area of the powder would be

about 1700 square centimeters,

or just enough to cover a pizza box. But

if we kept going and turned the same

sugar cube into nano sized powder.

Its surface area could cover several

football fields.

Now when something is broken down into

nano sized bits, a lot more can

change than just surface area. Which

brings us to our nano challenge.

OK, before we start our nano challenge, I

want to remind you that one nanometer is



of this. Now for the

challenge. Think of something from your

kitchen and imagine that if you broke it

down into nano-sized pieces, it could be

used to help propel rockets into outer

space. Is it

aluminum foil, baking soda,

coffee beans, or popping corn?

Don't just guess. Try to figure it out

and I'll be back with a hint later on in

the show. Now let's check in with Anushua

and Lara, who are about to rig their own

expl*si*n.

Oh, cool! It's a soda expl*si*n kit.

The thing that was different about our

soda expl*si*n kit is that our recipe

called for rocks, pebbles, and sand

instead of candy. The idea is to drop

different sizes of rocks into the soda to

see how the amount of surface area

affects the expl*si*n. We've weighed the

rocks, so we'll know that we're using the

same amount each time. The directions

explain that the rocks release the carbon

dioxide in the soda, causing an eruption.

Sort of like if you shook the bottle. We

want to see how high each soda geyser

shoots. We'll use these flags strung on a

flagpole, kind of like you would a ruler.

There's a flag every three feet, so we

can estimate the height of the spray. For

backup, we'll record a video of the

geysers with my camera. Then we can

compare our data to see which size rocks

makes the biggest spray. We put the

rocks into a tube that we screw on top of

the bottle. When we pull the string, the

rocks are dropped into the soda.

Our first test only went nine feet high.

That was really disappointing. I know,

there are big rocks. You'd think they'd

go higher. Shake, shake, shake, shake,

shake The pebbles made the soda sh**t 15

feet high. Whoa. That was

really high. That was crazy, though.

Finally, we got to the sand.

The sand sent the soda 20 feet up in the

air.

We took the results of our experiment and

put them on a chart.

MachMood came out, and we showed him our

chart. The rocks only went up to nine

feet, which is small in comparison to the

pebbles, which went up to 15 feet, which

is still small in comparison to the sand,

which went above our measurements and

above the flagpole to about 20 feet.

Well, that's what happens when you have

so much more surface area. What if we

ground up the stand into, like, nano size?

Wouldn't it make, like, a huge expl*si*n?

For sure. But there are more practical

applications when it comes to

nanotechnology, like solar energy. Let's

take a look at our science house and show

you what I mean. The roof of our science

house is covered with solar cells, like

the ones in this panel. Oh, that's so

cool. But how do they work?Well, the

solar cells create electricity using

sunlight. The cells in the science house

create all the energy that the house

needs. How come every building doesn't

have this technology?Well, they're

expensive. But at the University of

Minnesota, there's a scientist named

Janice Berker who's creating solar cells

using nanotechnology. We weren't done

yet. Laura and I decided to go green,

so we hopped a bus across town to the

university. We make solar

cells that are made-up of zinc oxide

nanowires. First, Janice showed us two

slides, one that didn't have the

nanowires on it. This one's clear, and it

looks like glass. And one that did.

Ooh, it's very smooth. And the next step

in our solar cell processis to place

these films into a dye. And what the dye

does is it absorbs the light so it can

transfer that light energy into

electrical energy. Because the zinc oxide

nanowires have more surface area, the

surface area, they can soak in more dye.

So will that nano solar cell actually

work?Let's go test it and see. So we're

going to use this ordinary desk lamp as

the sun. There you

go. Oh, wow. So cool.

So that energy is making that spin?

Exactly. Electrons are traveling through

there and giving power to that motor

underneath the disk, which caused it to

spin. Let's try it with a silicon solar

cell. Let

the sun shine. It's spinning way faster.

Yeah, right now, the current output of

the silicon solar cell is a lot more than

that of the nanosolar cell. We're hoping

that in the future, we can make nanosolar

cells that are just as efficient as

silicon solar cells. But cost less. Be

sure to cover a lot of ground learning

about surface area. The surface area.

Surface area. The surface area. I know.

I'm exhausted. Who knew that sugar

cookies, exploding soda, and saving the

Earth all had something in common?

Speaking of cookies, I'm starving.

Wow, those two went from cookies to solar

cells by asking one simple question. They

were following the trail of a surprising

idea that small isn't just smaller, it

can be really different. When some things

are nano-ized, they change a lot.

How much is a lot?Try thinking of it this

way. Imagine a dinner plate

at the nano scale. It isn't necessarily a

tiny, tiny plate. It could change

so much that it becomes a cheeseburger.

Strange stuff happens in the nano world,

which brings up the question, what if

these tiny particles turn into nano

invaders?

Let's go.

My name is Kristy Haynes. What do you do?

I'm an assistant professor of chemistry

at the University of Minnesota. What

we're trying to do is figure out the

design rules for nanoparticles so that we

know how to control whether or not they

influence cell behavior. My group

is pretty big, but our nanoparticle

toxicity team... But our nanoparticle

toxicity team is four graduate students

and an undergraduate. It's a pretty great

team, actually. Current

estimates suggest that over 600 consumer

products contain nanoparticles, and the

number is doubling every month. Oops,

oops, oops. I'm always feeling...

Products all around us contain

nanoparticles, and we just want to make

sure that they're safe.

In our lab, the way to assess the safety

of nanomaterials is by seeing how they

affect one cell's ability to communicate

with another. So first we need to

actually make the nanoparticles. You're

there creating. Thinking. The next thing

we have to do is figure out where the

nanoparticles go inside the cells.

And then lastly, we do the really the

thing that we're really specialists at.

It's a highly specialized field. And So

what we're doing is looking at that cell

conversation. Oh, look, it's talking. We

have our cells in culture where they're

busy communicating with each other,

rather like playing a game of Marco Polo.

The tools in our lab let us listen in to

that conversation.

Marco Polo. The cells can respond in

many different ways after exposure to

nanoparticles. There could be noresponse.

There could be a change in response.

The response can be quieter.

Or, after nanoparticle exposure, the

response can be normal.

Scientists need to figure out the rules.

You know, obviously if we haveProducts

that contain nanoparticles, we want to

make sure they're safe, whether they're

OK in a biological system or whether

they're not, and whether they're OK in an

environmental system or not. For me, the

most exciting thing is that you get to

work as a big team and that you're making

contributions to society and that you get

to be creative all the time. Christy is

really great. She is always working with

us and always making sure our questions

are answered. She's excited about what

she's doing. It's really important and

she's always able to keep you thinking.

Everything we do on this project is.

Exciting right now because nobody else is

working in this area. This is definitely

cutting edge stuff. So every experiment

we do, the results are things that people

have never seen before.

It's good to know that scientists like

Christy are keeping an eye on

nanoparticles. Which reminds me,

have you thought of what might be sitting

on a shelf in your kitchen, secretly

biding its time before stepping out to

help blast rockets into space?This

is a tough one. So let's review the

choices. Is it a aluminum foil,

B baking soda, C coffee

beans, or D popping corn?

I'll give you only one hint. It's

name has two words.

Eric, they all do. OK, this time a

real hint. You probably would not find

this in your grandmother's kitchen when

she was young now. Zoomer

and I are heading out to inner space.

Yo, Zoomer.

Good to see you, buddy. The

eye sees us, Zoomer, and it's blinking. I

hope it doesn't blink on us. We're

heading straight for the green speckled

iris, which is a muscle that opens and

closes the black hole of the pupil that

lets more or less light in. Hold on,

Zoomer. We're going in.

Cool. It's like a bloodshot superhighway.

This is the back of the eye, otherwise

known as the retina. See that circle of

light right there?That is the optic

nerve, which hooks up the brain with the

signals from the eye. Let's zoom in a

little closer.

Now we're magnified almost 1500

times, and we see the retina as if one

edge was cut. See those cells right there?

Those are called rods. No,

not hot rods, Zoomer. These rods help us

see things in low light. And let's zoom

way, way in.

Check out those folds. Those folds are

less than 10 nanometers wide, and they

add even more surface area for picking up

light. I feel like I'm being followed.

I know we're getting too small. Let's

zoom on out.

life-size again. I feel

good. And now another Nano story

about how small is really different. In

fact, Aledi and Ivonne find out that

sometimes gold is red and silver

is yellow. Gold is gold is

gold is gold.

I'm Aletti. And I'm Yvonne. And we live

in Chicago, and we love exploring

it.

What do you think we should do next?Her

and Massage having their anniversary.

Maybe we can go check it out. Let's go.

Welcome to MSI. MSI

stands for the Museum of Science and

Industry. They've always got so many cool

things to see here. We checked out the

U-505 submarine. Let's go! Look

out! And an exhibit called Genetics.

That's where we saw a baby chick

hatchery. Peep, peep, peep. Peep, peep,

peep, peep, peep.

Look, it's the glasses brand. Let's go

check it out. We read that ancient

Egyptians invented glassmaking over



made from sand. Right, it's really hard

to believe that all this brown, gritty

stuff makes these beautiful pieces of

glass. I also didn't know that glass was

made from metal, like copper or silver.

What's that about?It

was cool to see how many different things

glass goes into. Some of it's really

useful, and some of it is totally

artistic. The museum has all

kinds of special shows. Today, we found a

demonstration all about glassblowing. We

met Annette and G. Bryan, who are both

glassblowers from the Corning Museum of

Glass. They take drawings from museum

visitors and make them into real glass

objects. Well, if you girls would like to

make a design, we'd be happy to make it

out of hot glass for you. Let's do it.

We're gonna make a beautifuldragonfly

today. Now, we melt

clear glass in our furnace. 2,100

degrees Fahrenheit. It's the same

temperature as a volcano. We add

the color to the glass by rolling it

through crushed-up colored glass called

frit, and frit has metal added to

it. It's metals that give the glass its

color.

Even back in the Middle Ages, glass

artisans were using different metals to

color the glass. That got me thinking.

What would it have been like to be a

glass maker way back then?

Where are we at?I think we're in the

Middle Ages. Let's make

glass. Is the glass done yet,

m'lady?I think it is. It's

beautiful. I think it's a

dragonfly.

Oh, cool. What do you think of the

dragonfly?It looks just like the picture.

It's awesome. Thanks. It's red, it's

green, it's yellow, it's blue. This is

the stained glass that we're about to do.

The

Bodie Studio of Architectural Arts is a

family of stained glass makers that go

back six generations. And then we met

Erin Bodie. Hi. We were

curious how you color your glass. Do you

use crushed up glass with minerals of

metal in it like the glassblowers do?

Yeah, we do use minerals. In the Middle

Ages, they used gold and silver to color

their glass. Gold like like my bracelet.

Yes, gold would make a red similar to

this piece of glass right here. And the

silver would make a yellow amber like

this. We just didn't get how gold can

make red and silver can make yellow. So

we headed off to investigate. We went to

visit Mark, a graduate student at

Northwestern University. So what can I do

for you ladies today?We saw some stained

glass, and we were just wondering how

gold and silver can make colors like red

and yellow. Well, it's because of

nanoscience. Nanoscience. I thought that

had something to do with robots. No, that

just means something is really, really

small, right?You're right, nanometer is

really small. When you have gold and

silver nanoparticles that are that small,

they give you different colors than the

gold and silver that you normally see.

Here we have gold and silver. The silver

looks white, but the gold actually looks

gold. We struck gold. We're rich.

Is this nano gold?Not yet. It's actually

a gold compound. In order to make the

nano-sized gold, we have to take it

through a chemical process. First step is

to weigh some out and mix it up with

water. Let's do it. We mixed up the gold

with some water and put it in a special

plate with a stirring magnet in the

beaker so the solution got stirred and

heated up at the same time. Once the gold

solution started boiling, we added a

chemical, and after a few minutes, it

turned dark red. Wow! So,

well, what's it about the gold that made

it change to red?When we added the second

chemical, it starts clustering the gold

up on itself to make little particles.

They interact with the light differently,

so you see different colors. We tried

silver, too, and saw that white-silver

powder became yellow once the solution

was mixed. We experimented with more gold

and silver particles and got even more

colors. The gold solution gave us red and

purple. And the silver solution gave us

yellow, dark yellow, orange, red, and

purple, too. Scientists beautiful.

Scientists can be beautiful, too. I am

beautiful No matter what

they say How are these nanoparticles

turning these solutions different colors?

Well, it has to do with the size of the

particles. How do you know how small they

are?I can show you. Let's go take a look.

Then Mark fired up his scanning electron

microscope for us. He took pictures of

the nanogold and nanosilver particles

from each solution we mixed. They're so

clumpy. Yeah, these small particles with

some of the chemicals that we added to

the solution, it makes them want to stick

together and make larger and larger

clusters. Mark told us that it was the

size of the particles that affected the

colors we saw. I want to measure one of

the particles from the purple solution.

All right, so just pick your particle and

draw a line. It's almost 17

nanometers across. We looked at the

pictures of our nanoparticles and took

measurements of the particles' sizes.

Then Mark showed us how to turn our

solutions into suncatchers by mixing them

with a special plastic. Then we baked it

in the oven, just like cookies.

Thanks for answering our questions. Bye!

See you later. We decided to make a chart

that compared the size of the

nanoparticles to the colors we saw. As we

increased the size of the nanoparticles,

thechanged. And now we know why gold

turns stained glass red and silver turns

stained glass yellow. It's so cool that

the people in the Middle Ages were using

nanotechnology and stained glass and

didn't even know it. It was cool of them

to put gold and silver in their glass to

make these cool colors and did different

experiments just like we did. I wonder if

we're artists or nanoscientists. Maybe

we're both.

Aletti and Yvonne will never look at

silver and gold the same way.

Nanoparticles can reflect light

differently than big chunks of the same

stuff. Here's an everyday example.

Whenever they let me out of the studio,

which is not often, I might add, I like

to go surfing. And when I do, I

use sunscreen. Now my zinc oxide

sunblock used to look like this.

Attractive, huhThe regular

zinc oxide reflects light as

white, but.

Some clever scientist

figured out how to make nanoparticles of

zinc oxide so small that they don't

scatter light, but instead

it goes on clear.

What else could nanoscience change?Well,

how about?Shoes that clean themselves,

or underwater cell phones, or perhaps

laptops that weigh less than a magazine.

Wait a nanosecond!

Do I think nanotechnology is safe or

unsafe?I would trust it

to be safe, and I would hope that it was

safe. I think that if

nanotechnology is tested well, it's safe.

It's really complicated. The

public in general has to decide whether

they think it's a good thing for them or

not. It's both safe and unsafe.

I think you should worry about it. Since

it's small, it could be. powerful. Nano

things get a little more reactive. I

don't want to blow up using

nanotechnology. Nanotechnology scares me

a little bit. Nanotechnology hasn't done

anything wrong yet. It depends on what

your nano size. I don't know. I would

be concerned about how nanotechnology

would decompose in a landfill. I think we

need to do a lot more testing. It could

definitely be a good thing and it could

definitely be a bad thing. It just

depends on how it's used.

I didn't think like that when I was 12.

Those were smart answers. Tell us what

you think could go wrong with

nanotechnology. Here's how.

Click on over to the Dragonfly TV website

at pbskidsgo.org. Stream a cool

DFTV video, try your hand at the new

Nanobots game, or tell us what you think

about nanotechnology. It's your place to

share your ideas.

Finally, it's time to answer today's nano

challenge. Have you thought about

something from your kitchen that could be

broken down into tiny nano-sized bits

and then used to help propel a rocket one

last time?Is it A aluminum foil,

B baking soda, C coffee

beans, or D popping corn?

I actually guessed popping corn and you

were wrong, but man enough to admit it.

The correct answer is aluminum foil,

or just call it aluminum. Tiny

nanoparticles of aluminum become really

flammable at the nanoscale. The aluminum

increases the speed of the expl*si*n and

the rocket blasts off into space. That's

because the nanoaluminum particles

are more reactive due to the

greater surface area exposed.

Okay, I think they've got it now.

Buh-bye. And now

time for a Nano sign-off. See you next

time on Dragonfly TV.

Let's drop! Yeah

Come

on!Shake, shake, shake, shake, a

shake, yeah A shake, shake, shake, shake,

a shake, yeah A shake, shake, shake,

shake, a shake, yeah A shake,

shake, shake, a shake, yeah A shake,

shake, shake, shake, a shake, yeah

Major funding for Dragonfly TV is

provided by...

The National Science Foundation.

Supporting education and research across

all fields of science and engineering.

The National Science Foundation, where

discoveries begin.

PBS Kids.