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NARRATOR:
By the light
of an ancient campfire,
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a discovery was made that
changed the course of history.
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MAN:
We don't know exactly
how it happened,
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but I sometimes wonder whether
it wasn't a complete accident.
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NARRATOR:
Whether by chance
or through sheer determination,
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once humankind learned how
to harness the power of fire,
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we left the Stone Age behind,
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forging our way
into the modern world
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with copper, bronze,
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iron, and steel-- the metals.
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MAN:
A world without metals
would not have tall buildings,
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it would not have fast vehicles,
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you wouldn't be able
to have electricity.
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Really, our entire modern world
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is built on the backbone
of metals.
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NARRATOR:
Our journey begins with a metal
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that's transformed life on Earth
through its beauty.
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A metal that fortune hunters
were willing to die for,
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and not just in the movies.
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WOMAN:
There's nothing more beautiful
than gold, nothing in the world.
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You just feel it
when you see it.
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Ancient people valued gold
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before the concept of currency
or money even existed.
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It's something that people
intrinsically knew had worth.
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Gold is absolutely magical.
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Gold is the most fantastic
jewelry metal to work with.
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It's so soft, it's so flexible,
it's like butter.
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Working with gold ruins you
for any other metal.
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You're never the same again.
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NARRATOR:
Jeanette, a master jeweler,
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is making a pair
of gold earrings.
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I specialize in ancient
jewelry-making techniques.
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The kind of expertise
and skill that were used
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for making jewelry
really made it an art form.
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I make my own wire and sheet...
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(hammering)
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...and practice techniques
like granulation.
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The technique I'm going to use
for the hanging fringe
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actually originates from Troy
from about 2450 BC.
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VINCI:
Gold is unique
among the elements.
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Gold is extremely resistant
to oxidation, to rusting.
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If you make an object
out of gold,
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it's the one thing that you have
that doesn't degrade.
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So to ancient people,
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that must have been very,
very appealing.
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CAINES:
The color of gold draws you in.
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Ancient people saw it
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and knew that it was something
incredibly special.
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NARRATOR:
Gold is not only beautiful,
it's rare.
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In fact,
if you take all the gold
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that's been mined to date,
it's estimated it would fill
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about a third
of the Washington Monument.
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But to understand
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what makes this rare
and noble metal last forever,
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we need to take a closer look--
a much, much closer look.
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Using one of the most powerful
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electron microscopes
in the world,
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David Muller studies
the elements.
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MULLER:
Probably the most fun in the lab
is when we put something in
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and the picture comes up
and you look and you go,
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"Wow, that's not
what I expected.
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That's interesting."
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And that's usually the start
of a new scientific discovery.
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NARRATOR:
Today, Muller is observing
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the curious behavior of gold,
atom by atom.
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All elements are made of atoms.
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Inside is a nucleus filled
with positively charged protons
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along with neutrons that have
no charge at all.
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Swirling around the nucleus
in a cloud
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are negatively charged
electrons.
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It's the relationship between
gold's nucleus and its electrons
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that holds the key
to its resilience.
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MULLER:
We're now at 7,000 times
magnification,
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seven times higher than
the highest magnification
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of an optical microscope.
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And if we zoom up some more,
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we start to see
there's this nice pattern.
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These are little islands
of gold.
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And if we zoom up a little bit
further on them,
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we'll start to see little bright
spots all by themselves.
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Those are individual atoms.
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NARRATOR:
Every one of these clusters
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contains thousands
of bright dots,
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thousands of gold atoms.
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MULLER:
Little gold atoms
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form small clusters,
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and they keep rearranging
and changing.
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They're not static,
they're not stable.
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They're dynamic--
they're moving all the time.
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NARRATOR:
Gold atoms love to be together.
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But when it comes to bonding
with other elements,
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they're downright antisocial.
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When atoms bond,
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they do it through
their outermost electrons
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by sharing or swapping them.
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But gold's 79 protons
fight the urge
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because they have
an immense positive charge.
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MAN:
That positive charge
pulls in the electrons.
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The real consequence is that
the outermost electrons in gold
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are much less available
for doing chemistry
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than we might otherwise expect.
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NARRATOR:
That's why gold doesn't bond
with elements like oxygen
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that cause metals
to tarnish and rust.
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CAINES:
The reason that
we're able to appreciate
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the gold masterpieces
from 2400 BC
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is because gold lasts forever.
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It's just as beautiful today
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as it was
thousands of years ago.
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You can't say that
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about anything else
that you could work in.
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NARRATOR:
How did such
a unique metal form?
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WOMAN:
It's not easy
to make an element.
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You need temperatures
that are extreme,
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and we're talking
millions of degrees.
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The heavier the element,
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the hotter the temperatures
required to make it.
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And you find those temperatures
in the cores of stars
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that are ten times the mass
of the sun or greater.
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NARRATOR:
It's within the intense heat
and pressure
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of these massive cores
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that the elements
progressively take shape,
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bonding together
in a process called fusion.
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VINCI:
You can sort of imagine
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building up all the elements
that exist in the universe
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by taking a pile of neutrons
and protons and electrons
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and putting them together
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to build up bigger and bigger
and bigger atoms.
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NARRATOR:
When the number of protons
and electrons hit 26,
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forming iron, the process stops.
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SHIELDS:
Once iron's made in the core,
that's it.
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There's no more available energy
for fusion.
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Those massive stars will explode
and go what's called supernova.
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One of the key
open questions, though, was
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what about the heavier elements?
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What about gold and platinum
and uranium?
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Where do those come from?
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NARRATOR:
At the end of supernova
explosions,
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new kinds of stars are formed
called neutron stars.
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They often come in pairs--
binary stars.
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BERGER:
They're extremely dense
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and compact and heavy.
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It weighs about one-and-a-half
times the mass of our sun,
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but it's the size of a city like
New York or London or Boston.
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And they incorporate
a lot of neutrons,
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which is why they're called
neutron stars.
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NARRATOR:
Some scientists theorize that
elements heavier than iron
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were created in the collision
of two neutron stars.
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What happens when they collide?
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(explosion)
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Fusion on a massive scale.
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The elements were spread
throughout the cosmos,
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so they were in the mix
when our solar system formed
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4.5 billion years ago.
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And later, more were delivered
to Earth
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by comets and asteroids.
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(rumbling explosions)
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Most of the elements
on the periodic table
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came to us from space.
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We classify them in groups
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defined by their
characteristics.
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The largest group is the metals,
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and one of the most beautiful
by far is gold.
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Now this ancient treasure
is going back to space
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onboard the most advanced
telescope ever built.
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MAN:
It's the next big
space telescope.
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We like to call it Hubble 2.0.
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NARRATOR:
Hubble 2.0 is the James Webb
Space Telescope.
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MOUNTAIN:
In 2018, we're going to launch
this incredible telescope,
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the largest space telescope
mankind has ever built,
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and we're going to send it
a million miles into space
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to stare at the earliest part
of the universe,
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and it will all rely
on two ounces of gold.
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NARRATOR:
The ultra-thin layers of gold
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that coat the telescope's
mirrors
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give it the power to detect
galaxies light years away.
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MOUNTAIN:
Hubble has sort of found
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the edge of the visible
universe,
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but we know there's
a whole universe beyond that
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at wavelengths called
infrared wavelengths.
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NARRATOR:
And that's where gold
comes into the picture.
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MAN:
Infrared light
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is invisible to our eyes,
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but we can detect it as heat.
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And that's why this
thermal infrared camera
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will pick it up.
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So this is my hand
as viewed by the camera,
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and it's about 97 degrees
Fahrenheit.
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Now let's look at my hand
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reflected in this ordinary
silver-coated mirror.
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It says that my hand is
84 degrees Fahrenheit,
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which is a lot less than 97,
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and that's because
the silver-coated mirror
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is not a perfect reflector
of infrared light.
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But if we try this
gold-coated mirror...
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Now, when I pass
my hand's reflection
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over the gold,
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it says that my hand is
97 degrees Fahrenheit.
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And so what this shows
is that gold
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is an almost perfect reflector
of infrared light,
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00:10:19,286 --> 00:10:21,753
and that's why we coat
all of the mirrors
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of the James Webb telescope
in gold--
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so that it has
an almost perfect view
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of the infrared
invisible universe.
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MOUNTAIN:
Gold is that ancient treasure
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that we've lusted over
over mankind's history,
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and here we are
in the 21st century using this
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to actually unlock
the secrets of the universe
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and perhaps the origins
of where we came from.
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What a wonderful historical
transformation.
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NARRATOR:
Historically, this glittering
treasure of the earth
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could be found in riverbeds
and streams.
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But in order to leave
the Stone Age behind,
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we needed another metal,
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one strong enough
to shape into tools.
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00:11:06,166 --> 00:11:09,934
And we found it
in the flames of a fire.
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Copper, atomic number 29--
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00:11:15,609 --> 00:11:21,579
29 electrons, 29 protons,
and 35 neutrons--
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is embedded in a mineral
called malachite.
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00:11:26,286 --> 00:11:29,387
Malachite has this incredible
color, doesn't it?
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It's like a Wizard of Oz
Emerald City green.
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Malachite has been
really important
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00:11:33,994 --> 00:11:35,994
throughout the history
of our civilization.
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This is probably the first
mineral that humans used
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to actually extract
copper metal.
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Just imagine the following.
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Someone comes home
with a beautiful green rock--
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malachite.
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NARRATOR:
They decide to grind it
into a powder
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and throw it into a campfire.
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A magical process occurs.
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NARRATOR:
Nature puts on a light show
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as the edges of the flames
turn emerald green.
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00:12:05,559 --> 00:12:07,659
SELLA:
The flame suddenly becomes
greenish.
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You get these incredible colors.
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You have no idea
where they come from,
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but it certainly provides
entertainment.
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And at the same time,
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that beautiful green rock
slowly turns black.
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NARRATOR:
The beautiful green malachite
has burnt away.
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What's left behind is copper
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00:12:26,780 --> 00:12:31,049
combined with oxygen
from the air-- copper oxide.
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If you left it in the fire
overnight to burn,
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00:12:34,588 --> 00:12:37,922
then the transformation
would have gone even further.
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NARRATOR:
But in order to free copper
from oxygen
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00:12:41,328 --> 00:12:44,863
requires another ingredient,
carbon,
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00:12:44,965 --> 00:12:48,166
which is conveniently provided
by charcoal--
247
00:12:48,268 --> 00:12:50,668
the residue of burning wood.
248
00:12:50,771 --> 00:12:53,505
SELLA:
I want to recreate that for you.
249
00:12:53,607 --> 00:12:56,407
NARRATOR:
Sella drops a disk
of copper oxide
250
00:12:56,510 --> 00:12:58,042
into a crucible of charcoal
251
00:12:58,145 --> 00:13:01,613
and heats it up
in a modern day fireplace:
252
00:13:01,715 --> 00:13:03,615
the microwave.
253
00:13:03,717 --> 00:13:07,051
SELLA:
What heat really means is
the molecules
254
00:13:07,154 --> 00:13:09,921
and atoms begin to move
much, much faster.
255
00:13:10,023 --> 00:13:12,757
Now it's possible
for the carbon
256
00:13:12,859 --> 00:13:14,926
to actually strip away
the oxygen,
257
00:13:15,028 --> 00:13:21,032
disappearing off invisibly
into the air as carbon dioxide.
258
00:13:21,134 --> 00:13:25,069
But the next morning, the person
who's cleaning up the fireplace,
259
00:13:25,172 --> 00:13:26,971
almost certainly a woman,
260
00:13:27,073 --> 00:13:30,742
would've found tiny
little shiny nodules
261
00:13:30,844 --> 00:13:32,577
lying amongst the ash.
262
00:13:32,679 --> 00:13:34,379
That would've been metal.
263
00:13:34,481 --> 00:13:37,382
This is a magical transformation
264
00:13:37,484 --> 00:13:40,018
that would suddenly have
given you a material
265
00:13:40,120 --> 00:13:42,554
that you could shape,
that you could reuse,
266
00:13:42,656 --> 00:13:44,656
that you could make tools with.
267
00:13:44,758 --> 00:13:47,091
This was power indeed.
268
00:13:47,194 --> 00:13:51,062
This was a birth
of a whole new technology.
269
00:13:51,164 --> 00:13:53,665
NARRATOR:
This was copper.
270
00:13:53,767 --> 00:13:57,902
Once our ancestors discovered
how to free metal from stone--
271
00:13:58,004 --> 00:14:00,371
the art of smelting--
272
00:14:00,473 --> 00:14:06,144
they had a material they could
shape into bowls and tools.
273
00:14:06,246 --> 00:14:09,981
But they also discovered it has
another surprising quality.
274
00:14:10,083 --> 00:14:12,784
An ancient Egyptian
medical text
275
00:14:12,886 --> 00:14:15,486
dating back to 1600 BC
276
00:14:15,589 --> 00:14:20,725
reveals copper was used as
a disinfectant to clean wounds.
277
00:14:20,827 --> 00:14:25,797
It was also used to make
surgical tools.
278
00:14:25,899 --> 00:14:28,066
As late as the 19th century,
279
00:14:28,168 --> 00:14:30,268
during a cholera epidemic
in Paris,
280
00:14:30,370 --> 00:14:34,505
copper workers seemed to be
immune to the disease.
281
00:14:34,608 --> 00:14:36,274
But by the 1940s,
282
00:14:36,376 --> 00:14:38,343
with the development
of antibiotics,
283
00:14:38,445 --> 00:14:42,881
people lost interest in copper,
its medicinal powers forgotten.
284
00:14:44,517 --> 00:14:46,484
Until now.
285
00:14:46,586 --> 00:14:49,220
At the University
of Southampton,
286
00:14:49,322 --> 00:14:51,589
Bill Keevil has set out to prove
287
00:14:51,691 --> 00:14:54,826
copper can help solve
a dangerous problem:
288
00:14:54,928 --> 00:14:57,328
hospital-borne infections.
289
00:14:57,430 --> 00:15:01,733
KEEVIL:
If a jumbo jet full of people
crashed each day
290
00:15:01,835 --> 00:15:03,434
and everyone died,
would you fly?
291
00:15:03,536 --> 00:15:04,602
Probably not.
292
00:15:04,704 --> 00:15:07,972
That's how many people die
in America each day
293
00:15:08,074 --> 00:15:09,841
from hospital-acquired
infection.
294
00:15:09,943 --> 00:15:14,245
NARRATOR:
Hospitals are a breeding ground
for dangerous superbugs.
295
00:15:14,347 --> 00:15:18,383
Just about any surface you touch
is a hot zone.
296
00:15:18,485 --> 00:15:20,952
KEEVIL:
We know superbugs are perfectly
happy to survive
297
00:15:21,054 --> 00:15:23,788
for many weeks
on a dry touch surface
298
00:15:23,890 --> 00:15:25,723
such as stainless steel
or plastics.
299
00:15:25,825 --> 00:15:27,492
So we need something that works
300
00:15:27,594 --> 00:15:31,362
24 hours a day,
seven days a week.
301
00:15:31,464 --> 00:15:33,965
NARRATOR:
Could copper be an answer?
302
00:15:34,067 --> 00:15:36,034
Keevil puts it to the test.
303
00:15:36,136 --> 00:15:39,103
He takes a piece of copper
304
00:15:39,205 --> 00:15:43,241
and a metal commonly used
in hospitals, stainless steel,
305
00:15:43,343 --> 00:15:46,344
and coats them
with the superbug MRSA,
306
00:15:46,446 --> 00:15:50,348
along with a green
fluorescent dye.
307
00:15:50,450 --> 00:15:53,851
Next, they place it
in a microscope.
308
00:15:53,954 --> 00:15:55,119
Please start your clocks,
309
00:15:55,221 --> 00:15:56,988
and we will follow
this experiment
310
00:15:57,090 --> 00:15:58,423
over the next five minutes.
311
00:15:58,525 --> 00:16:01,059
NARRATOR:
At first, the bacteria
312
00:16:01,161 --> 00:16:02,961
on the copper
and stainless steel
313
00:16:03,063 --> 00:16:05,029
glows bright green.
314
00:16:05,131 --> 00:16:06,631
But within minutes,
315
00:16:06,733 --> 00:16:13,504
the copper in the screen
on the right turns black.
316
00:16:13,606 --> 00:16:15,573
This is what they looked like
and this is after five minutes.
317
00:16:15,675 --> 00:16:18,176
So you can see they're all dead.
318
00:16:18,278 --> 00:16:21,279
NARRATOR:
How does copper do it?
319
00:16:21,381 --> 00:16:24,716
Scientists suspect
it has something to do
320
00:16:24,818 --> 00:16:29,821
with the membrane of a superbug,
which has an electrical charge.
321
00:16:29,923 --> 00:16:34,926
When it meets up with copper,
a kind of short circuit occurs.
322
00:16:35,028 --> 00:16:37,328
The copper penetrates
the membrane,
323
00:16:37,430 --> 00:16:40,498
leaving it with gaping,
oozing holes.
324
00:16:40,600 --> 00:16:46,471
The copper invades the superbug,
destroying its DNA.
325
00:16:46,573 --> 00:16:48,673
If there's no DNA,
there's no growth,
326
00:16:48,775 --> 00:16:51,409
and, in fact,
there's no chance of mutation,
327
00:16:51,511 --> 00:16:54,445
and, therefore,
you can't get resistance.
328
00:16:54,547 --> 00:16:57,048
NARRATOR:
Copper's ability to kill germs
329
00:16:57,150 --> 00:17:00,818
could one day save
millions of lives.
330
00:17:00,920 --> 00:17:05,323
But it's already revolutionized
the way we live,
331
00:17:05,425 --> 00:17:08,860
because copper has another
extraordinary ability:
332
00:17:08,962 --> 00:17:13,798
it conducts the electricity
that powers the planet.
333
00:17:13,900 --> 00:17:16,934
Metals are extremely
unusual materials.
334
00:17:17,037 --> 00:17:19,804
They can conduct electricity
extremely well.
335
00:17:19,906 --> 00:17:22,974
And when we think
about conducting electricity,
336
00:17:23,076 --> 00:17:24,675
what that means is that
337
00:17:24,778 --> 00:17:27,011
there are electrons
within the material
338
00:17:27,113 --> 00:17:30,081
which are able to move.
339
00:17:30,183 --> 00:17:32,550
Sometimes this is described as
a sea of electrons.
340
00:17:32,652 --> 00:17:35,920
You can kind of picture these
individual atom cores
341
00:17:36,022 --> 00:17:39,424
and then this sea of electrons
all around them.
342
00:17:39,526 --> 00:17:43,861
NARRATOR:
Metal atoms are arranged
in orderly rows and columns.
343
00:17:43,963 --> 00:17:46,864
In between those columns
are electrons
344
00:17:46,966 --> 00:17:49,300
that are able to move around.
345
00:17:49,402 --> 00:17:50,968
SELLA:
When we apply a voltage
with a battery,
346
00:17:51,071 --> 00:17:54,205
we can start to draw electrons
347
00:17:54,307 --> 00:17:57,608
so that they all move
collectively in one direction.
348
00:17:57,710 --> 00:17:59,544
NARRATOR:
With a voltage applied,
349
00:17:59,646 --> 00:18:03,114
electrons hop
from one atom to the next.
350
00:18:03,216 --> 00:18:04,282
SELLA:
That's what gives us
351
00:18:04,384 --> 00:18:07,685
the electric currents
that are so useful.
352
00:18:07,787 --> 00:18:11,122
NARRATOR:
While all metals
can conduct electricity,
353
00:18:11,224 --> 00:18:13,391
copper is one of the best.
354
00:18:13,493 --> 00:18:15,626
And it's abundant.
355
00:18:15,728 --> 00:18:21,099
The worldwide supply is
about six trillion pounds.
356
00:18:21,201 --> 00:18:23,167
But the qualities
that make copper
357
00:18:23,269 --> 00:18:25,403
the metal of choice
to wire the planet
358
00:18:25,505 --> 00:18:27,872
also limit its usefulness.
359
00:18:27,974 --> 00:18:31,909
That sea of electrons
not only conducts electricity;
360
00:18:32,011 --> 00:18:35,646
it creates flexible bonds
between the atoms.
361
00:18:35,748 --> 00:18:37,148
VINCI:
The atom cores
362
00:18:37,250 --> 00:18:39,617
can move through this
sea of electrons
363
00:18:39,719 --> 00:18:41,552
in a relatively easy way,
364
00:18:41,654 --> 00:18:43,254
and that's what makes metals
malleable.
365
00:18:43,356 --> 00:18:47,325
NARRATOR:
But a metal like copper,
which is malleable enough
366
00:18:47,427 --> 00:18:50,495
to be stretched into thin,
flexible cable,
367
00:18:50,597 --> 00:18:53,865
does not a dagger make.
368
00:18:53,967 --> 00:18:56,200
SELLA:
Copper is actually too soft.
369
00:18:56,302 --> 00:19:00,004
A blade made of copper
loses its edge within moments.
370
00:19:00,106 --> 00:19:02,406
And yet, by combining it
371
00:19:02,509 --> 00:19:06,344
with other rocks
in the fireplace made of tin,
372
00:19:06,446 --> 00:19:08,179
you could make a material
373
00:19:08,281 --> 00:19:11,482
which was stronger, harder,
and stiffer.
374
00:19:11,584 --> 00:19:13,985
That was bronze.
375
00:19:14,087 --> 00:19:16,521
NARRATOR:
Around 2500 BC,
376
00:19:16,623 --> 00:19:20,758
humankind took the art
of smelting one step further
377
00:19:20,860 --> 00:19:24,829
by mixing metals
to create an alloy.
378
00:19:24,931 --> 00:19:26,864
MULLER:
When you look at copper,
it's pretty boring--
379
00:19:26,966 --> 00:19:28,332
every single atom
looks the same.
380
00:19:28,434 --> 00:19:29,867
But when you look at bronze,
381
00:19:29,969 --> 00:19:31,269
there are two different types
of atoms.
382
00:19:31,371 --> 00:19:32,770
There's copper and there's tin.
383
00:19:32,872 --> 00:19:35,339
NARRATOR:
Adding tin to copper
384
00:19:35,441 --> 00:19:37,775
changes the properties
of the metal.
385
00:19:37,877 --> 00:19:39,844
The larger tin atoms
386
00:19:39,946 --> 00:19:43,214
restrict the movement
of the copper atoms.
387
00:19:43,316 --> 00:19:45,816
VINCI:
It makes it more difficult
for the atoms
388
00:19:45,919 --> 00:19:49,187
to move past one another
to change shape.
389
00:19:49,289 --> 00:19:51,055
Saying that it's more difficult
to move them around
390
00:19:51,157 --> 00:19:52,957
is equivalent to saying that
the metal is stronger.
391
00:19:53,059 --> 00:19:57,795
SELLA:
Bronze would've provided useful
implements for agriculture,
392
00:19:57,897 --> 00:20:00,531
but more importantly,
it would've provided you
393
00:20:00,633 --> 00:20:03,501
with weapons
to establish your dominance.
394
00:20:03,603 --> 00:20:06,037
And dominance, of course,
means control,
395
00:20:06,139 --> 00:20:08,406
and control means power.
396
00:20:10,343 --> 00:20:13,311
NARRATOR:
The movies paint a vivid picture
397
00:20:13,413 --> 00:20:17,782
of how bronze transformed
the nature of warfare.
398
00:20:17,884 --> 00:20:19,550
It's the bronze age,
so without bronze,
399
00:20:19,652 --> 00:20:20,885
you don't stand a chance
in battle.
400
00:20:20,987 --> 00:20:23,187
Bronze is like no other material
401
00:20:23,289 --> 00:20:25,089
people would have handled
before.
402
00:20:25,191 --> 00:20:28,759
With it, you can make
harder weapons,
403
00:20:28,861 --> 00:20:30,895
you can make sharper blades,
404
00:20:30,997 --> 00:20:32,496
and you can make them
consistently.
405
00:20:32,599 --> 00:20:34,131
You can cast them in mold
406
00:20:34,234 --> 00:20:36,534
and make them always
of equal quality.
407
00:20:36,636 --> 00:20:39,003
With bronze, you can,
for the first time, really,
408
00:20:39,105 --> 00:20:41,505
equip hundreds,
thousands of warriors
409
00:20:41,608 --> 00:20:43,674
with the same types of weapons,
410
00:20:43,776 --> 00:20:47,111
all of which will perform
and be equally lethal.
411
00:20:47,213 --> 00:20:49,814
So it probably meant
a revolution in warfare.
412
00:20:51,884 --> 00:20:55,886
NARRATOR:
But not all swords
are created equal.
413
00:20:55,989 --> 00:21:00,124
Back in 1965,
a group of archeologists
414
00:21:00,226 --> 00:21:03,094
discovered more than 50
ancient tombs
415
00:21:03,196 --> 00:21:05,830
in the Hubei province of China.
416
00:21:05,932 --> 00:21:07,398
During the excavation,
417
00:21:07,500 --> 00:21:10,101
they unearthed something
extraordinary.
418
00:21:10,203 --> 00:21:14,705
Jigao Hu was one of the first
people to lay eyes on it.
419
00:21:14,807 --> 00:21:18,442
Hu, an expert in the
preservation of ancient relics,
420
00:21:18,544 --> 00:21:24,649
vividly remembers seeing
a most unusual sword.
421
00:21:24,751 --> 00:21:28,853
(translated): The sword had
a golden sheen to it
422
00:21:28,955 --> 00:21:30,855
and had a decent weight to it.
423
00:21:30,957 --> 00:21:34,659
It had the shine
of fresh copper.
424
00:21:34,761 --> 00:21:37,695
There was no rust at all.
425
00:21:37,797 --> 00:21:41,799
NARRATOR:
Although it had been buried
for more than 2,400 years,
426
00:21:41,901 --> 00:21:44,869
the sword was perfectly
preserved.
427
00:21:44,971 --> 00:21:47,838
Hu found eight characters
428
00:21:47,940 --> 00:21:51,609
written in ancient Chinese
script on the base of the blade.
429
00:21:51,711 --> 00:21:54,945
They identified
the sword's owner:
430
00:21:55,048 --> 00:21:57,481
Goujian, the king of Yue,
431
00:21:57,583 --> 00:22:02,019
a famous ruler
in the 5th century BC.
432
00:22:02,121 --> 00:22:05,756
(translated):
Everyone came to see the sword,
433
00:22:05,858 --> 00:22:10,127
ecstatic because there were
characters on it.
434
00:22:10,229 --> 00:22:12,897
One young man was
particularly excited,
435
00:22:12,999 --> 00:22:15,833
and he tried to reach for it
and he bumped into me.
436
00:22:15,935 --> 00:22:18,969
I leaped forward a little
and must've touched the sword,
437
00:22:19,072 --> 00:22:21,639
and the sword made a cut
438
00:22:21,741 --> 00:22:26,210
about two to three centimeters
on my hand.
439
00:22:26,312 --> 00:22:29,747
There were droplets of blood
coming from my wound.
440
00:22:29,849 --> 00:22:33,684
It wasn't a deep cut,
but a cut anyhow,
441
00:22:33,786 --> 00:22:36,253
like a shaving razor.
442
00:22:36,356 --> 00:22:39,590
The sword was that sharp.
443
00:22:39,692 --> 00:22:43,794
Later, they tested the sword.
444
00:22:43,896 --> 00:22:47,298
It could cut through
20 sheets of paper.
445
00:22:47,400 --> 00:22:52,436
It was so beautifully crafted,
I was astounded.
446
00:22:55,708 --> 00:22:58,442
(translated): The Goujian sword
is well preserved
447
00:22:58,544 --> 00:23:00,945
because of its burial condition.
448
00:23:01,047 --> 00:23:03,280
It is dry,
and no water leaked inside.
449
00:23:03,383 --> 00:23:05,383
Thus, it did not rust.
450
00:23:05,485 --> 00:23:08,986
NARRATOR:
But its longevity
may also be due
451
00:23:09,088 --> 00:23:11,555
to the extraordinary
craftsmanship
452
00:23:11,657 --> 00:23:15,393
with which it was made.
453
00:23:15,495 --> 00:23:17,795
(translated):
The smelting technology
from ancient times
454
00:23:17,897 --> 00:23:19,397
has been lost.
455
00:23:19,499 --> 00:23:23,834
But recently, there are people
who start to imitate the styles.
456
00:23:23,936 --> 00:23:28,539
However, they can't manage
to replicate its sharpness.
457
00:23:28,641 --> 00:23:35,212
The sophistication cannot
match up to ancient times.
458
00:23:35,314 --> 00:23:39,150
NARRATOR:
But bronze has another
resounding quality.
459
00:23:39,252 --> 00:23:41,952
(bell rings deeply)
460
00:23:42,054 --> 00:23:44,155
It's the perfect metal
to forge a bell.
461
00:23:46,492 --> 00:23:50,795
In South Korea,
master craftsman Song Chang-Il
462
00:23:50,897 --> 00:23:55,599
is making a ten-ton bell
for a Buddhist temple.
463
00:23:55,701 --> 00:23:57,635
After decades of experience,
464
00:23:57,737 --> 00:24:01,071
combined with an artist's
instincts,
465
00:24:01,174 --> 00:24:04,175
he knows exactly what it takes
466
00:24:04,277 --> 00:24:08,412
to make a bell
with the perfect ring.
467
00:24:08,514 --> 00:24:12,817
First, ten tons
of copper and tin
468
00:24:12,919 --> 00:24:16,720
are heated
to 1,150 degrees Celsius.
469
00:24:17,957 --> 00:24:19,523
When the time is right,
470
00:24:19,625 --> 00:24:24,595
Chang-Il pours his concoction
into a massive clay mold.
471
00:24:24,697 --> 00:24:27,298
The metal is so hot,
472
00:24:27,400 --> 00:24:32,670
it takes two-and-a-half days
for the bronze to cool.
473
00:24:32,772 --> 00:24:38,075
Finally, the mold
is carefully removed
474
00:24:38,177 --> 00:24:44,114
and the bell is tested
for the first time.
475
00:24:45,585 --> 00:24:48,085
(bell rings deeply)
476
00:24:48,187 --> 00:24:49,653
SELLA:
That sound that we hear
477
00:24:49,755 --> 00:24:54,325
is really telling us
about the stiffness
478
00:24:54,427 --> 00:24:56,794
and the resilience
of the material.
479
00:24:56,896 --> 00:25:00,798
So when we hear
the ringing sound of a bell,
480
00:25:00,900 --> 00:25:04,168
the entire material
kind of swings.
481
00:25:04,270 --> 00:25:05,503
It becomes elastic
482
00:25:05,605 --> 00:25:08,272
and can then come back
and go forward
483
00:25:08,374 --> 00:25:10,174
and back and forward and back.
484
00:25:10,276 --> 00:25:12,376
(bell rings deeply)
485
00:25:12,478 --> 00:25:14,979
(applause)
486
00:25:15,081 --> 00:25:16,647
NARRATOR:
Over thousands of years,
487
00:25:16,749 --> 00:25:20,484
through trial and error,
craftsmen like Chang-Il
488
00:25:20,586 --> 00:25:24,822
discovered that the perfect ring
could only be achieved
489
00:25:24,924 --> 00:25:27,324
with the perfect recipe:
490
00:25:27,426 --> 00:25:32,296
a balance between tin
and copper.
491
00:25:32,398 --> 00:25:37,368
But around 1200 BC,
as the use of bronze spread,
492
00:25:37,470 --> 00:25:40,437
and with supplies of tin scarce,
493
00:25:40,540 --> 00:25:44,341
once again,
the flames of a fire
494
00:25:44,443 --> 00:25:46,944
brought us a powerful metal.
495
00:25:47,046 --> 00:25:49,680
Iron.
496
00:25:49,782 --> 00:25:53,350
Atomic number 26--
497
00:25:53,452 --> 00:25:59,390
26 electrons, 26 protons,
and 30 neutrons.
498
00:25:59,492 --> 00:26:02,426
Freeing iron from stone
499
00:26:02,528 --> 00:26:04,895
meant taking the technology
of smelting
500
00:26:04,997 --> 00:26:07,197
one giant step further.
501
00:26:09,468 --> 00:26:13,971
Charcoal burns at
about 1,000 degrees Celsius,
502
00:26:14,073 --> 00:26:20,144
but to smelt iron, the flames
need to be a lot hotter.
503
00:26:20,246 --> 00:26:26,150
The answer: a technology that
could literally fan the flames--
504
00:26:26,252 --> 00:26:29,520
a furnace called a bloomery.
505
00:26:29,622 --> 00:26:33,157
This ancient furnace was built
with heat-resistant walls
506
00:26:33,259 --> 00:26:37,061
made of earth, clay, or stone.
507
00:26:37,163 --> 00:26:39,763
At the base,
pipes allowed air to enter
508
00:26:39,865 --> 00:26:43,334
through an elaborate system
of bellows.
509
00:26:43,436 --> 00:26:50,207
The air was pumped manually
by hand or by foot.
510
00:26:50,309 --> 00:26:54,378
SELLA:
Anyone who's been camping
and has made a little campfire
511
00:26:54,480 --> 00:26:58,349
knows that if you lean down
and you blow into the embers,
512
00:26:58,451 --> 00:27:02,252
what they do is they glow
much more brightly.
513
00:27:02,355 --> 00:27:04,154
Because you're introducing
oxygen
514
00:27:04,256 --> 00:27:06,724
and you're raising
its concentration,
515
00:27:06,826 --> 00:27:07,992
you're making it more available.
516
00:27:08,094 --> 00:27:11,929
NARRATOR:
A fire needs oxygen to burn,
517
00:27:12,031 --> 00:27:16,600
and the more oxygen,
the hotter the flames.
518
00:27:16,702 --> 00:27:20,004
SELLA:
The reaction of oxygen
with the charcoal,
519
00:27:20,106 --> 00:27:21,939
which makes carbon dioxide,
520
00:27:22,041 --> 00:27:24,108
is one which generates
an increase in temperature.
521
00:27:24,210 --> 00:27:27,878
You get a release of heat.
522
00:27:27,980 --> 00:27:33,517
NARRATOR:
Oxygen made the fire hot enough
to separate iron from stone,
523
00:27:33,619 --> 00:27:38,288
and once again, metal
transformed the way we live,
524
00:27:38,391 --> 00:27:41,859
from tools to weapons.
525
00:27:41,961 --> 00:27:44,461
In time,
the bloomery was replaced
526
00:27:44,563 --> 00:27:48,465
with the more powerful
blast furnace.
527
00:27:48,567 --> 00:27:54,138
And by the 20th century,
iron was everywhere.
528
00:27:54,240 --> 00:27:55,939
The Industrial Revolution
529
00:27:56,042 --> 00:27:59,476
changed nearly every aspect
of life on earth.
530
00:27:59,578 --> 00:28:01,945
But there was a catch.
531
00:28:02,048 --> 00:28:04,381
In the process of smelting iron,
532
00:28:04,483 --> 00:28:08,752
impurities called slag
are left behind.
533
00:28:08,854 --> 00:28:12,956
Slag weakens metal.
534
00:28:13,059 --> 00:28:16,427
Over hundreds of years,
craftsmen discovered that
535
00:28:16,529 --> 00:28:20,130
if iron is hammered and reheated
over and over again,
536
00:28:20,232 --> 00:28:24,435
it gets purer and stronger.
537
00:28:26,405 --> 00:28:28,439
VINCI:
Over time, bit by bit,
538
00:28:28,541 --> 00:28:31,341
they discovered
how to get more and more
539
00:28:31,444 --> 00:28:33,677
of what they wanted
in terms of properties.
540
00:28:33,779 --> 00:28:36,213
But they certainly didn't have
any understanding
541
00:28:36,315 --> 00:28:38,749
at anything even remotely
like the atomic level
542
00:28:38,851 --> 00:28:40,684
of what was going on.
543
00:28:40,786 --> 00:28:44,955
NARRATOR:
But now we understand that
at the atomic level,
544
00:28:45,057 --> 00:28:48,859
an extraordinary transformation
was taking place.
545
00:28:48,961 --> 00:28:52,930
Iron was turning into one
of the strongest alloys
546
00:28:53,032 --> 00:28:56,433
Earth-- steel.
547
00:28:56,535 --> 00:28:58,102
While hammering
drove out the slag,
548
00:28:58,204 --> 00:29:00,104
the charco in the fire
549
00:29:00,206 --> 00:29:04,441
provided an essential
ingredient: carbon.
550
00:29:04,543 --> 00:29:08,145
The combination of iron
and carbon to make steel
551
00:29:08,247 --> 00:29:12,416
is almost a unique combination
in the world,
552
00:29:12,518 --> 00:29:14,284
and key to it is that
553
00:29:14,386 --> 00:29:16,687
the iron atom
and the carbon atom
554
00:29:16,789 --> 00:29:18,622
are very different sizes.
555
00:29:18,724 --> 00:29:21,558
When you add a little bit
of carbon to iron,
556
00:29:21,660 --> 00:29:25,162
it tends to hide
in the little gaps
557
00:29:25,264 --> 00:29:27,464
in between the large iron atoms.
558
00:29:27,566 --> 00:29:31,435
NARRATOR:
The way tin transforms copper
into bronze,
559
00:29:31,537 --> 00:29:35,873
carbon turns iron into steel.
560
00:29:35,975 --> 00:29:38,776
VINCI:
And this is one of the amazing
things about steel.
561
00:29:38,878 --> 00:29:41,812
Just using more or less
just these two elements,
562
00:29:41,914 --> 00:29:45,516
iron and carbon, you can create
lots of different properties
563
00:29:45,618 --> 00:29:48,519
that can be useful
for different applications.
564
00:29:48,621 --> 00:29:53,524
NARRATOR:
To demonstrate the difference
between iron and steel,
565
00:29:53,626 --> 00:29:55,325
Vinci got access to a piece
566
00:29:55,427 --> 00:29:59,563
of one of the most famous
iron towers ever built.
567
00:29:59,665 --> 00:30:02,199
VINCI:
This is our piece
of the Eiffel Tower.
568
00:30:02,301 --> 00:30:04,802
NARRATOR:
Discarded after a repair.
569
00:30:04,904 --> 00:30:06,136
HELEN CHAN:
I never thought in my life
570
00:30:06,238 --> 00:30:08,205
I would be holding a piece
of the Eiffel Tower.
571
00:30:08,307 --> 00:30:10,908
I mean, I've been up the Eiffel
Tower a couple of times.
572
00:30:11,010 --> 00:30:14,111
NARRATOR:
The Eiffel Tower is made
of wrought iron,
573
00:30:14,213 --> 00:30:16,513
which has less carbon
than steel.
574
00:30:16,615 --> 00:30:18,348
VINCI:
When the Eiffel Tower was built,
575
00:30:18,450 --> 00:30:21,351
wrought iron construction
was really at its peak.
576
00:30:21,453 --> 00:30:23,554
It's an amazing structure
577
00:30:23,656 --> 00:30:25,823
using an amazing material,
especially for its day.
578
00:30:25,925 --> 00:30:29,426
NARRATOR:
How does the strength
of the wrought iron
579
00:30:29,528 --> 00:30:33,697
in the Eiffel Tower hold up
against steel?
580
00:30:33,799 --> 00:30:36,567
Rick Vinci and Helen Chan are
about to find out.
581
00:30:36,669 --> 00:30:39,803
VINCI:
Not only do we get to hold
a piece of the Eiffel Tower,
582
00:30:39,905 --> 00:30:41,572
we also get to cut it up
and bend it
583
00:30:41,674 --> 00:30:42,573
and maybe even break it.
584
00:30:42,675 --> 00:30:46,476
NARRATOR:
They conduct a bends test
585
00:30:46,579 --> 00:30:48,946
to determine how much force
can be applied
586
00:30:49,048 --> 00:30:51,515
to the wrought iron
before it bends.
587
00:30:51,617 --> 00:30:52,549
Here we go.
588
00:30:53,819 --> 00:30:58,088
NARRATOR:
It not only bends; it breaks.
589
00:30:58,190 --> 00:30:59,489
(loud crack)
590
00:30:59,592 --> 00:31:01,124
VINCI:
Wow, it broke.
591
00:31:01,227 --> 00:31:03,961
Okay.
This is actually cracked.
592
00:31:04,063 --> 00:31:06,897
NARRATOR:
When they test the steel,
593
00:31:06,999 --> 00:31:11,034
there are similarities
and differences.
594
00:31:12,137 --> 00:31:15,005
Well, it actually seems
as if the two samples
595
00:31:15,107 --> 00:31:17,374
behave pretty much
the same.
596
00:31:17,476 --> 00:31:20,010
The load that it took to bend it
was comparable.
597
00:31:22,214 --> 00:31:23,914
Okay, so I see
two differences right away.
598
00:31:24,016 --> 00:31:26,316
First of all,
the wrought iron bar cracked
599
00:31:26,418 --> 00:31:27,684
and the modern steel didn't.
600
00:31:27,786 --> 00:31:30,354
But I see another really
important difference,
601
00:31:30,456 --> 00:31:31,922
which is the modern steel bar
602
00:31:32,024 --> 00:31:35,225
is only half the thickness
of the Eiffel Tower bar,
603
00:31:35,327 --> 00:31:38,629
despite the fact that it carried
exactly the same load.
604
00:31:38,731 --> 00:31:41,798
So all that means is if
you are using a modern steel,
605
00:31:41,901 --> 00:31:43,400
for the same amount of material,
606
00:31:43,502 --> 00:31:45,402
you can support
four times the load.
607
00:31:45,504 --> 00:31:46,403
(loud crack)
608
00:31:46,505 --> 00:31:47,070
Wow.
609
00:31:47,172 --> 00:31:48,505
All right.
610
00:31:48,607 --> 00:31:51,742
NARRATOR:
In fact, around the time
the Eiffel Tower was built,
611
00:31:51,844 --> 00:31:55,879
steel was already on its way
to becoming the metal of choice
612
00:31:55,981 --> 00:31:57,514
for building high.
613
00:31:57,616 --> 00:32:01,952
Chicago's towering ten-story
Home Insurance Building,
614
00:32:02,054 --> 00:32:06,490
the world's first skyscraper,
had a steel frame.
615
00:32:06,592 --> 00:32:09,359
VINCI:
Steel had a huge influence
616
00:32:09,461 --> 00:32:11,428
on the development
of this country
617
00:32:11,530 --> 00:32:13,563
as an dustrial nation.
618
00:32:13,666 --> 00:32:19,202
NARRATOR:
And today, steel can do things
that are hard to imagine.
619
00:32:19,305 --> 00:32:21,038
Nothing demonstrates that
620
00:32:21,140 --> 00:32:24,107
quite like the Beijing
National Stadium,
621
00:32:24,209 --> 00:32:26,843
nicknamed the Bird's Nest,
622
00:32:26,946 --> 00:32:35,419
42,000 tons packed into a design
that seems to defy logic.
623
00:32:35,521 --> 00:32:38,922
Engineer Michael Kwok
was a project manager
624
00:32:39,024 --> 00:32:42,759
for the design and construction
of the Bird's Nest.
625
00:32:42,861 --> 00:32:44,428
It's more like a jigsaw puzzle,
626
00:32:44,530 --> 00:32:47,297
you just try to figure out
how this was put together.
627
00:32:51,036 --> 00:32:53,370
VINCI:
It is very unlike
628
00:32:53,472 --> 00:32:56,740
pretty much any other structure
that's been built.
629
00:32:56,842 --> 00:32:59,276
If you want to make
a strong structure,
630
00:32:59,378 --> 00:33:01,478
there are certain classic shapes
that work very, very well,
631
00:33:01,580 --> 00:33:02,913
and the truss is a classic one.
632
00:33:03,015 --> 00:33:06,917
If you look at bridges
all over the place,
633
00:33:07,019 --> 00:33:09,086
they have these
triangular elements,
634
00:33:09,188 --> 00:33:11,321
these truss elements that are
very, very strong.
635
00:33:11,423 --> 00:33:14,191
NARRATOR:
The geometry of a triangle
636
00:33:14,293 --> 00:33:17,194
makes it an inherently
stable shape.
637
00:33:17,296 --> 00:33:19,162
Put several of them in a row
638
00:33:19,264 --> 00:33:21,498
and they distribute the weight
of a structure
639
00:33:21,600 --> 00:33:23,300
to its load-bearing beams.
640
00:33:23,402 --> 00:33:26,770
VINCI:
But the Bird's Nest
looks nothing like that.
641
00:33:26,872 --> 00:33:30,340
NARRATOR:
But looks can be deceiving.
642
00:33:30,442 --> 00:33:34,277
24 sets of columns
connect to a series of trusses
643
00:33:34,380 --> 00:33:36,847
that support the roof.
644
00:33:36,949 --> 00:33:40,984
All this is hidden
behind a maze of steel.
645
00:33:41,086 --> 00:33:45,122
VINCI:
You can't make that out of just
any run-of-the-mill steel.
646
00:33:45,224 --> 00:33:48,158
You need a particularly
high-strength and tough steel.
647
00:33:48,260 --> 00:33:51,294
NARRATOR:
The stadium is made
of two kinds of steel.
648
00:33:51,397 --> 00:33:55,599
The recipe for the trusses
provides extra strength.
649
00:34:15,087 --> 00:34:19,222
NARRATOR:
But to create the beauty
of its winding exterior
650
00:34:19,324 --> 00:34:22,392
required steel
with more flexibility.
651
00:34:22,494 --> 00:34:26,463
For a massive steel structure
like this,
652
00:34:26,565 --> 00:34:31,001
the combination of flexibility
and strength is critical...
653
00:34:32,971 --> 00:34:37,607
especially in an earthquake-
prone region like Beijing.
654
00:35:03,735 --> 00:35:08,105
NARRATOR:
The bowl of the stadium,
made primarily of concrete,
655
00:35:08,207 --> 00:35:10,907
does not have the elasticity
of steel.
656
00:35:11,009 --> 00:35:15,078
So the engineers and architects
came up with an innovative idea:
657
00:35:15,180 --> 00:35:18,081
separate concrete from steel;
658
00:35:18,183 --> 00:35:21,852
make them work as two
independent structures.
659
00:35:31,263 --> 00:35:34,064
NARRATOR:
The extraordinary properties
inherent in steel
660
00:35:34,166 --> 00:35:38,435
make it possible for engineers
like Michael Kwok
661
00:35:38,537 --> 00:35:44,574
to build structures like this
that capture the imagination.
662
00:35:57,022 --> 00:36:01,458
NARRATOR:
Today, by mixing different types
of steel for different purposes,
663
00:36:01,560 --> 00:36:04,427
engineers have taken
the art of steelmaking
664
00:36:04,530 --> 00:36:07,664
to new heights-- literally.
665
00:36:07,766 --> 00:36:13,236
The tallest bridge in the world,
the Millau Viaduct in France,
666
00:36:13,338 --> 00:36:17,007
is made of steel that contains
an element that's quite rare:
667
00:36:17,109 --> 00:36:19,643
niobium.
668
00:36:19,745 --> 00:36:23,580
It is a soft,
whitish gray metal,
669
00:36:23,682 --> 00:36:26,850
and if you add it to steel,
670
00:36:26,952 --> 00:36:30,554
you get a stronger,
lighter material.
671
00:36:30,656 --> 00:36:33,890
VINCI:
When you think about a solid
piece of metal,
672
00:36:33,992 --> 00:36:36,159
it just looks like
it's all the same.
673
00:36:36,261 --> 00:36:38,228
But in fact,
if you really zoom in,
674
00:36:38,330 --> 00:36:40,497
that chunk of metal
is typically made up
675
00:36:40,599 --> 00:36:42,732
of lots of little individual
metal grains.
676
00:36:42,834 --> 00:36:46,836
And it turns out that if you can
make those grains really tiny,
677
00:36:46,939 --> 00:36:48,638
then it makes it
much more difficult
678
00:36:48,740 --> 00:36:51,641
for the atoms to move past
one another to change shape.
679
00:36:51,743 --> 00:36:55,679
So by making the grains tiny,
you make the metal stronger.
680
00:36:55,781 --> 00:36:59,950
Now, niobium prevents
the growth of these grains
681
00:37:00,052 --> 00:37:03,320
very effectively, and then
you can get incredible strength
682
00:37:03,422 --> 00:37:06,756
that comes from having this
very tiny grain size.
683
00:37:06,858 --> 00:37:10,393
NARRATOR:
Different kinds of steel
can have other additives,
684
00:37:10,495 --> 00:37:14,097
like nickel, chromium,
or manganese.
685
00:37:14,199 --> 00:37:17,901
But there's one
rather bizarre recipe
686
00:37:18,003 --> 00:37:22,939
that could help solve one
of the world's biggest problems.
687
00:37:23,041 --> 00:37:26,409
We've been seeing landfills
as a huge environmental burden,
688
00:37:26,511 --> 00:37:28,345
and of course it appears
that way on the surface
689
00:37:28,447 --> 00:37:32,315
because we don't know
what else to do with it.
690
00:37:32,417 --> 00:37:34,317
But if we can reform
end-of-life materials
691
00:37:34,419 --> 00:37:35,752
into completely different
products,
692
00:37:35,854 --> 00:37:39,956
then suddenly, landfills
shouldn't be seen as a burden;
693
00:37:40,058 --> 00:37:43,393
they should actually be seen
as this amazing possibility.
694
00:37:43,495 --> 00:37:44,728
It's a treasure.
695
00:37:44,830 --> 00:37:48,865
NARRATOR:
Veena Sahajwalla
has developed a way
696
00:37:48,967 --> 00:37:53,236
to recycle the stuff
nobody wants-- trash--
697
00:37:53,338 --> 00:37:55,438
and turn it into steel.
698
00:37:55,540 --> 00:37:57,140
SAHAJWALLA:
The most basic steel
699
00:37:57,242 --> 00:37:59,676
is nothing but an alloy
of iron and carbon.
700
00:37:59,778 --> 00:38:01,278
Well, guess what?
701
00:38:01,380 --> 00:38:03,613
We can find carbon in plastics.
702
00:38:03,715 --> 00:38:05,482
NARRATOR:
The first step:
703
00:38:05,584 --> 00:38:09,019
take some plastic
like this broken headlight.
704
00:38:09,121 --> 00:38:12,222
Look at what I got you!
705
00:38:12,324 --> 00:38:15,725
NARRATOR:
Cut off a piece and melt it down
706
00:38:15,827 --> 00:38:19,296
to a small pellet
chock full of carbon.
707
00:38:19,398 --> 00:38:23,633
Top it off with a lump
of pure iron.
708
00:38:25,404 --> 00:38:27,704
Place the combo
back in the furnace
709
00:38:27,806 --> 00:38:31,007
and heat it up.
710
00:38:31,109 --> 00:38:34,878
Now watch the alchemy unfold
711
00:38:34,980 --> 00:38:39,482
as the carbon in plastic
bonds with iron.
712
00:38:39,584 --> 00:38:41,951
SAHAJWALLA:
What's exciting here is that
713
00:38:42,054 --> 00:38:43,787
we're actually seeing
this high-temperature reaction
714
00:38:43,889 --> 00:38:45,789
taking place
right in front of our very eyes.
715
00:38:45,891 --> 00:38:47,123
We've got this liquid metal.
716
00:38:47,225 --> 00:38:51,628
We're now looking
at how this is interacting
717
00:38:51,730 --> 00:38:55,298
with this source of carbon,
which of course is the plastic
718
00:38:55,400 --> 00:38:58,335
that came from a waste
out of a car.
719
00:38:58,437 --> 00:39:00,236
Carbon from that plastic
720
00:39:00,339 --> 00:39:03,039
is actually able to dissolve
into liquid metal.
721
00:39:03,141 --> 00:39:05,909
So this is what's come out
of the furnace.
722
00:39:06,011 --> 00:39:08,511
We've dissolved the carbon
from the plastic
723
00:39:08,613 --> 00:39:10,580
into liquid iron.
724
00:39:10,682 --> 00:39:12,182
And of course,
what we have here is steel.
725
00:39:12,284 --> 00:39:14,918
NARRATOR:
After a decade of research,
726
00:39:15,020 --> 00:39:19,689
Veena's "green steel" is slowly
making its way out of the lab.
727
00:39:19,791 --> 00:39:23,626
Partnering with the manufacturer
One Steel,
728
00:39:23,729 --> 00:39:27,997
they have already recycled
over two million tires.
729
00:39:28,100 --> 00:39:31,201
Today's tires are made
of a synthetic rubber,
730
00:39:31,303 --> 00:39:34,704
produced from oil
rich in carbon--
731
00:39:34,806 --> 00:39:38,608
the perfect ingredient
for green steel.
732
00:39:38,710 --> 00:39:42,545
And when it comes
to greenhouse gases,
733
00:39:42,647 --> 00:39:46,249
Veena's steel requires
less coal to cook,
734
00:39:46,351 --> 00:39:49,652
and that reduces
its carbon footprint.
735
00:39:49,755 --> 00:39:51,154
As the saying goes, you know,
736
00:39:51,256 --> 00:39:53,490
one person's trash is
somebody else's treasure.
737
00:39:53,592 --> 00:39:54,691
Guess what?
738
00:39:54,793 --> 00:39:58,294
This could become
our society's treasure.
739
00:39:58,397 --> 00:40:00,230
I love steel because
it has really given us
740
00:40:00,332 --> 00:40:03,767
the structures that have
changed this world around us.
741
00:40:03,869 --> 00:40:10,707
NARRATOR:
Steel has given us the power
to build high and strong.
742
00:40:10,809 --> 00:40:15,345
But as wonderful and versatile
as it is, steel has limitations.
743
00:40:15,447 --> 00:40:20,617
VINCI:
One of the drawbacks to steel
is that it is relatively heavy.
744
00:40:20,719 --> 00:40:23,887
Iron is fairly dense,
and for its strength,
745
00:40:23,989 --> 00:40:25,922
you have to make
massive structures.
746
00:40:26,024 --> 00:40:27,757
And that's fine
if you're building a bridge,
747
00:40:27,859 --> 00:40:29,726
but it's not fine
if you're building something
748
00:40:29,828 --> 00:40:30,727
that needs to move.
749
00:40:30,829 --> 00:40:32,695
(engine roaring)
750
00:40:32,798 --> 00:40:35,565
NARRATOR:
And that's where
another extraordinary metal
751
00:40:35,667 --> 00:40:37,567
comes into the picture.
752
00:40:37,669 --> 00:40:43,273
Atomic number 13, aluminum
has just 13 electrons,
753
00:40:43,375 --> 00:40:47,110
13 protons, and 14 neutrons.
754
00:40:47,212 --> 00:40:50,113
In comparison
with a heavier metal like iron,
755
00:40:50,215 --> 00:40:51,881
which has twice the number
756
00:40:51,983 --> 00:40:54,417
of protons, electrons,
and neutrons,
757
00:40:54,519 --> 00:40:58,188
the aluminum atom
is incredibly light.
758
00:40:58,290 --> 00:41:00,590
SELLA:
Aluminum has
an ethereal lightness
759
00:41:00,692 --> 00:41:03,126
that no one could believe.
760
00:41:03,228 --> 00:41:06,763
VINCI:
And yet, it also has some
of the properties like steel
761
00:41:06,865 --> 00:41:09,098
that allow you
to modify its strength
762
00:41:09,201 --> 00:41:12,235
and its other characteristics
to optimize it.
763
00:41:12,337 --> 00:41:13,870
SELLA:
Aluminum has completely
764
00:41:13,972 --> 00:41:15,405
transformed our world,
765
00:41:15,507 --> 00:41:19,409
from the trivial tent pegs
of our tents
766
00:41:19,511 --> 00:41:21,544
to the frames of our aircraft,
767
00:41:21,646 --> 00:41:23,847
where it really makes
a difference.
768
00:41:23,949 --> 00:41:27,050
If we had to build our airplanes
out of steel,
769
00:41:27,152 --> 00:41:28,818
they would have to have
fuel tanks
770
00:41:28,920 --> 00:41:31,454
five or six times bigger
than they do now
771
00:41:31,556 --> 00:41:35,425
and would carry a third
of the passengers.
772
00:41:35,527 --> 00:41:38,127
VINCI:
Today's aluminum is really
fabulous stuff.
773
00:41:38,230 --> 00:41:40,430
If you can live
with a little bit less strength
774
00:41:40,532 --> 00:41:42,131
in exchange
for a lot less weight,
775
00:41:42,234 --> 00:41:44,000
then aluminum is
an excellent choice.
776
00:41:44,102 --> 00:41:46,536
But as we look to the future,
777
00:41:46,638 --> 00:41:49,873
another way to move forward
is to ask ourselves
778
00:41:49,975 --> 00:41:52,475
if what we have been doing
with metals for all these years
779
00:41:52,577 --> 00:41:54,344
is the only thing we can do.
780
00:41:54,446 --> 00:42:01,117
NARRATOR:
Imagine a material that is not
just light, not just strong,
781
00:42:01,219 --> 00:42:03,586
but flexible enough
to change its shape.
782
00:42:03,688 --> 00:42:06,189
WOMAN:
So I think of the Terminator
with this project,
783
00:42:06,291 --> 00:42:07,590
which is super fun,
784
00:42:07,692 --> 00:42:09,192
and I don't think I've seen
the Terminator
785
00:42:09,294 --> 00:42:10,059
since I was young,
786
00:42:10,161 --> 00:42:11,261
but one of the images
787
00:42:11,363 --> 00:42:14,764
that really stuck with me
is the T-1000,
788
00:42:14,866 --> 00:42:16,533
you know, the all-metal guy,
right?
789
00:42:16,635 --> 00:42:17,700
(gunshot)
790
00:42:17,802 --> 00:42:21,437
He can change shape
and then self-heals.
791
00:42:21,540 --> 00:42:23,106
Actually, our material
does all those things.
792
00:42:23,208 --> 00:42:26,876
NARRATOR:
This is metal foam,
793
00:42:26,978 --> 00:42:30,246
a combination
of metal and rubber.
794
00:42:30,348 --> 00:42:34,284
Heat it up and it morphs
into another shape.
795
00:42:34,386 --> 00:42:38,421
And when it's done,
it becomes a solid again.
796
00:42:38,523 --> 00:42:41,057
The idea of this metal foam
is that we can have sothing
797
00:42:41,159 --> 00:42:43,026
that changes its shape
dramatically,
798
00:42:43,128 --> 00:42:44,894
but then after it changes
its shape,
799
00:42:44,996 --> 00:42:46,729
have a lot of strength.
800
00:42:46,831 --> 00:42:51,367
NARRATOR:
What's the recipe
for making metal foam?
801
00:42:51,469 --> 00:42:55,405
First, take a dash
of Himalayan salt,
802
00:42:55,507 --> 00:42:58,441
add a little dragon skin--
803
00:42:58,543 --> 00:43:00,977
also known as
uncured silicon.
804
00:43:04,282 --> 00:43:07,283
Mix it up,
805
00:43:07,385 --> 00:43:10,853
pour the mixture into a mold,
806
00:43:10,956 --> 00:43:13,256
and let it cure.
807
00:43:13,358 --> 00:43:15,858
Remove the concoction
from the mold
808
00:43:15,961 --> 00:43:19,829
and place it
in an ultrasonic cleaner.
809
00:43:19,931 --> 00:43:24,167
This dissolves away
the Himalayan salt.
810
00:43:24,269 --> 00:43:28,738
What's left behind is a porous,
sponge-like material
811
00:43:28,840 --> 00:43:31,007
riddled with tiny crevices.
812
00:43:31,109 --> 00:43:34,410
Next, submerge the foam
into a bath
813
00:43:34,512 --> 00:43:37,180
of molten Field's metal.
814
00:43:37,282 --> 00:43:38,681
SHEPHERD:
Field's metal is
815
00:43:38,783 --> 00:43:42,518
a low-melting-temperature alloy
of indium, tin, and bismuth.
816
00:43:42,621 --> 00:43:46,623
So at 60 degrees Celsius,
it is a molten liquid.
817
00:43:46,725 --> 00:43:49,325
Below 60 degrees Celsius,
it's a frozen solid.
818
00:43:49,427 --> 00:43:53,029
NARRATOR:
The metal-covered foam
is sealed in a vacuum chamber,
819
00:43:53,131 --> 00:43:57,200
where the molten metal
seeps into those tiny crevices
820
00:43:57,302 --> 00:44:00,103
that were left behind
by the salt.
821
00:44:00,205 --> 00:44:03,272
Air trapped in the foam
is pushed out
822
00:44:03,375 --> 00:44:05,475
and rises to the surface.
823
00:44:05,577 --> 00:44:09,812
The sample is then removed
from the vacuum chamber
824
00:44:09,914 --> 00:44:12,148
and cooled down.
825
00:44:12,250 --> 00:44:14,984
Once it's at room temperature,
it hardens again.
826
00:44:15,086 --> 00:44:17,987
Shepherd hopes one day,
827
00:44:18,089 --> 00:44:21,991
metal foam will be able
to make like a bird.
828
00:44:22,093 --> 00:44:23,626
(chirping)
829
00:44:23,728 --> 00:44:25,428
One of the problems I'm trying
to solve with this material
830
00:44:25,530 --> 00:44:28,297
is inspired by a puffin.
831
00:44:28,400 --> 00:44:30,400
A puffin can fly,
832
00:44:30,502 --> 00:44:33,569
but then it can dive underwater
to catch fish,
833
00:44:33,672 --> 00:44:35,505
so it has to sweep
its wings back
834
00:44:35,607 --> 00:44:37,974
in order to not have
its wings torn off.
835
00:44:38,076 --> 00:44:40,877
So in an artificial version
of the puffin,
836
00:44:40,979 --> 00:44:42,412
we would want a vehicle
837
00:44:42,514 --> 00:44:45,348
that could turn from a plane
to an underwater glider.
838
00:44:45,450 --> 00:44:48,584
This idea is quite imaginative
and a far-reaching goal,
839
00:44:48,687 --> 00:44:50,820
but we are currently working
on a wing
840
00:44:50,922 --> 00:44:53,956
that we will coat
in a skin of this metal foam,
841
00:44:54,059 --> 00:44:56,993
and we're going to try it out
on a radio-controlled airplane
842
00:44:57,095 --> 00:44:58,928
in the next year.
843
00:44:59,030 --> 00:45:04,434
NARRATOR:
But metal foam could find
another home-- in space.
844
00:45:04,536 --> 00:45:06,936
SILBERSTEIN:
If you think about kind of
a limited resources setup,
845
00:45:07,038 --> 00:45:09,005
certainly if you're, like,
in outer space
846
00:45:09,107 --> 00:45:11,007
and you have a limited number
of things
847
00:45:11,109 --> 00:45:12,375
you can bring with you,
848
00:45:12,477 --> 00:45:14,410
and maybe you don't know exactly
what tools you need,
849
00:45:14,512 --> 00:45:15,745
but here you have this material,
850
00:45:15,847 --> 00:45:18,448
and you can really
change its shape
851
00:45:18,550 --> 00:45:21,184
and then lock it in
to whatever you need.
852
00:45:21,286 --> 00:45:24,187
So you can take it one day
and use it as a wrench,
853
00:45:24,289 --> 00:45:26,756
and take it the next day
and use it as a hammer.
854
00:45:26,858 --> 00:45:28,524
NARRATOR:
One day, metal foam
855
00:45:28,626 --> 00:45:31,561
could make its way
into your toolbox.
856
00:45:31,663 --> 00:45:33,496
SHEPHERD:
Eventually, we believe
857
00:45:33,598 --> 00:45:36,666
this composite could be used
for reconfigurable tools.
858
00:45:36,768 --> 00:45:40,236
At thipoint, we think there
are some flaws in the structure
859
00:45:40,338 --> 00:45:42,105
that may cause it to fracture,
860
00:45:42,207 --> 00:45:43,606
but these are
engineering problems
861
00:45:43,708 --> 00:45:45,074
that we think are very solvable.
862
00:45:45,176 --> 00:45:47,944
NARRATOR:
While some researchers
863
00:45:48,046 --> 00:45:51,781
are exploring new ways
to combine materials,
864
00:45:51,883 --> 00:45:55,151
others, like David Muller,
865
00:45:55,253 --> 00:45:58,821
are fascinated with a newly
discovered treasure,
866
00:45:58,923 --> 00:46:01,791
the strongest material
ever found:
867
00:46:01,893 --> 00:46:03,359
graphene.
868
00:46:03,461 --> 00:46:08,364
Made of pure carbon, graphene
behaves a lot like a metal,
869
00:46:08,466 --> 00:46:12,301
but it's about 200 times
stronger than steel
870
00:46:12,403 --> 00:46:15,304
and harder than diamonds,
871
00:46:15,406 --> 00:46:21,210
even though it's just
one atom thick.
872
00:46:21,312 --> 00:46:22,779
Graphene has incredible
strength.
873
00:46:22,881 --> 00:46:25,114
Combined with incredible
strength,
874
00:46:25,216 --> 00:46:28,151
it has incredible flexibility.
875
00:46:28,253 --> 00:46:32,188
NARRATOR:
How strong is graphene?
876
00:46:32,290 --> 00:46:33,856
Some researchers estimate
877
00:46:33,958 --> 00:46:37,293
it would take an elephant
balanced on a pencil
878
00:46:37,395 --> 00:46:39,662
to break through
a sheet of graphene
879
00:46:39,764 --> 00:46:42,298
the thickness of Saran wrap.
880
00:46:44,602 --> 00:46:47,136
Where can it be found?
881
00:46:47,238 --> 00:46:49,972
You have to bake it.
882
00:46:51,442 --> 00:46:54,844
First, take a piece of copper
and place it in an oven.
883
00:46:54,946 --> 00:46:58,648
Fill it with a material
that contains carbon.
884
00:46:58,750 --> 00:47:00,249
David Muller uses methane,
885
00:47:00,351 --> 00:47:05,655
a gas that's a combination
of carbon and hydrogen.
886
00:47:05,757 --> 00:47:08,624
MULLER:
We knock all the hydrogen off
by heating it up very hot,
887
00:47:08,726 --> 00:47:11,327
so that gets turned
into just carbon atoms
888
00:47:11,429 --> 00:47:13,496
that are floating around
in a vapor.
889
00:47:13,598 --> 00:47:17,433
Those carbon atoms fall down
and bombard a flat surface.
890
00:47:17,535 --> 00:47:20,970
So the way you think of this is
891
00:47:21,072 --> 00:47:24,941
my copper surface is just like
a cold window on a cold day,
892
00:47:25,043 --> 00:47:27,743
and then little bits of moisture
are in the air
893
00:47:27,846 --> 00:47:30,346
and they start to condense
onto my cold window,
894
00:47:30,448 --> 00:47:32,481
and instead of growing
little ice crystals
895
00:47:32,584 --> 00:47:34,617
that decorate all the way
across my window,
896
00:47:34,719 --> 00:47:36,953
I'm going to grow little
crystals of carbon
897
00:47:37,055 --> 00:47:39,889
that are going to decorate
my copper surface.
898
00:47:39,991 --> 00:47:42,325
And eventually,
these little crystals
899
00:47:42,427 --> 00:47:44,160
are going to grow bigger
and bigger and bigger
900
00:47:44,262 --> 00:47:45,928
until eventually,
they touch each other,
901
00:47:46,030 --> 00:47:48,464
and then I have one uniform
continuous sheet of carbon,
902
00:47:48,566 --> 00:47:50,867
and that will be the graphene.
903
00:47:50,969 --> 00:47:57,306
NARRATOR:
What makes this incredibly thin
layer of carbon so strong?
904
00:47:57,408 --> 00:48:02,111
It all comes down
to the arrangement of its atoms.
905
00:48:02,213 --> 00:48:06,649
When six carbon atoms bond,
they form a hexagon.
906
00:48:06,751 --> 00:48:11,053
And as more and more
carbon atoms join the group,
907
00:48:11,155 --> 00:48:13,756
more hexagons take shape.
908
00:48:13,858 --> 00:48:15,157
MULLER:
So you can imagine
909
00:48:15,260 --> 00:48:16,959
that if another carbon atom
comes down
910
00:48:17,061 --> 00:48:20,029
and lands over here,
right in the middle,
911
00:48:20,131 --> 00:48:21,931
it's got nothing to stick to.
912
00:48:22,033 --> 00:48:23,866
It's going to keep rolling
around,
913
00:48:23,968 --> 00:48:26,369
but then it gets to the edge
of the sheet of the graphene
914
00:48:26,471 --> 00:48:28,871
and says, "Wait a minute,
there's a dangling bond.
915
00:48:28,973 --> 00:48:30,673
I want to attach to that."
916
00:48:30,775 --> 00:48:32,608
And then it'll continue
to grow out,
917
00:48:32,710 --> 00:48:34,310
and that's why the sheet gets
bigger and bigger and bigger.
918
00:48:36,447 --> 00:48:38,147
NARRATOR:
Once the baking is done,
919
00:48:38,249 --> 00:48:42,118
the graphene-coated copper
is taken out of the oven
920
00:48:42,220 --> 00:48:45,621
and placed in a solution that
slowly etches the metal away.
921
00:48:47,892 --> 00:48:52,628
What's left is a small sheet
of graphene.
922
00:48:52,730 --> 00:48:56,933
Exactly what can you do
with a single layer of graphene
923
00:48:57,035 --> 00:49:00,469
that's so thin,
it's barely visible?
924
00:49:00,571 --> 00:49:03,339
So we could imagine graphene
would be very valuable
925
00:49:03,441 --> 00:49:05,174
for things on the nanoscale.
926
00:49:05,276 --> 00:49:09,111
NARRATOR:
Because it's both tiny
and strong,
927
00:49:09,213 --> 00:49:13,115
it could fit inside a cell
for medical applications
928
00:49:13,217 --> 00:49:16,919
or be placed in dust
for environmental monitoring.
929
00:49:17,021 --> 00:49:21,390
But graphene might also have
applications on the megascale.
930
00:49:21,492 --> 00:49:25,094
VINCI:
If you could build cables,
for instance,
931
00:49:25,196 --> 00:49:27,196
for holding up
suspension bridges.
932
00:49:27,298 --> 00:49:28,864
If you could get
to that size scale,
933
00:49:28,967 --> 00:49:31,033
then that would open up
934
00:49:31,135 --> 00:49:34,437
incredible new
engineering opportunities
935
00:49:34,539 --> 00:49:36,872
for creative people
to make structures
936
00:49:36,975 --> 00:49:38,874
that we really can only
dream of today.
937
00:49:38,977 --> 00:49:44,413
NARRATOR:
Is graphene the next big thing?
938
00:49:44,515 --> 00:49:47,350
No one can predict
if new materials
939
00:49:47,452 --> 00:49:52,521
like metal foam or graphene
will live up to their promise.
940
00:49:52,623 --> 00:49:55,057
(elephant trumpeting)
941
00:49:55,159 --> 00:49:58,060
But there's no doubt that metals
942
00:49:58,162 --> 00:50:00,396
have revolutionized
life on Earth,
943
00:50:00,498 --> 00:50:05,167
from the beauty of gold
to the smelting of copper
944
00:50:05,269 --> 00:50:09,071
to the creation of bronze
and steel.
945
00:50:09,173 --> 00:50:14,276
And in the future,
materials we can only dream of.
946
00:50:14,379 --> 00:50:18,047
SELLA:
And the astonishing thing
is that the work of engineers,
947
00:50:18,149 --> 00:50:21,484
of metallurgists,
and of chemists every year
948
00:50:21,586 --> 00:50:25,654
brings us new formulations,
new possibilities
949
00:50:25,757 --> 00:50:30,326
that makes things lighter,
stronger, stiffer,
950
00:50:30,428 --> 00:50:33,996
faster than anything
that came before.
951
00:50:41,606 --> 00:50:43,906
Earth's amazing
natural resources.
952
00:50:44,008 --> 00:50:46,208
We use them to build
our civilization.
953
00:50:46,310 --> 00:50:49,545
WOMAN:
I love steel because it has
really given us the structures
954
00:50:49,647 --> 00:50:51,680
that have changed this world
around us.
955
00:50:51,783 --> 00:50:54,517
But how will we power
our future?
956
00:50:54,619 --> 00:50:57,486
N:
The magic of the desert,
the sun, the sand,
957
00:50:57,588 --> 00:51:00,089
they produce a lot of energy
and they can power a whole city.
958
00:51:00,191 --> 00:51:02,191
The quest to fuel tomorrow.
959
00:51:02,293 --> 00:51:06,162
"Treasures of the Earth,"
next time on NOVA.
960
00:51:10,968 --> 00:51:12,902
r NOVA
is provided by the following:
961
00:51:33,024 --> 00:51:35,558
This NOVA program is
available on DVD.
962
00:51:35,660 --> 00:51:40,796
To order, visit shopPBS.org,
or call 1-800-play-PBS.
963
00:51:40,898 --> 00:51:43,399
NOVA is also available
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