All language subtitles for O2 The Molecule That Made Our World NG Naked Science 720p HDTV x264 AC3 MVGroup org_Subtitles01.UND

Narrator: This is the
story of a remarkable atom.

Just one of an
inconceivable number of

atoms that helped
create the world we know.

Toxic, but life giving.

Fragile, yet powerful.

Taking part in
countless chemical

reactions, yet
indestructible.

You could breathe in
atoms once breathed in

by Caesar, Cleopatra,
or Genghis Khan.

Blasting through
earth's history,

they are a crucial
part of earth's most

important events.

Shaping evolution.

From some of the
first life forms,

to the giant insects
of the coal swamps.

Helping life
invade dry land.

Playing a key role
as dinosaurs conquer

earth, and giving
energy to more familiar

creatures.

Yet this atom creates
so much precisely

because it's so
destructive.

Building up in earth's
early atmosphere,

it killed most life.

Today we can't
live without it.

The atom.

Amazing on its own.

With a chemical
partner,

it transformed earth.

We didn't know oxygen existed
until the 18th century.

Antoine Lavoisier and
his wife Marie-Anne are

intrigued by the
way materials burn.

At the time, scientists
believe burning is

caused by the release
of something called

phlogiston, found in
all flammable material.

But Lavoisier suspects
that air contains

different gasses,
each with different

properties.

He and his wife try
to isolate them.

When he slowly heats
mercury it turns into a

red powder.

And there's one-fifth
less air in the flask.

One of the gases must
have been absorbed.

Reheating the mercury
releases this gas back

into the atmosphere.

This was the gas they
were looking for.

Lavoisier calls
it "oxygen".

Today, we call
the gas O2,

because it's 2 oxygen
atoms bound together

and we know much more
about why it behaves

the way it does.

A single oxygen
atom consists of 8

electrons, orbiting a
tiny nucleus occupying

distinct shells.

But two of these shells
have space for another

electron.

Desperate to fill
these spaces,

oxygen is greedy
for more electrons.

It takes from
wherever it can,

making it one of
the most "reactive"

chemicals on earth.

If we follow this
particular atom we'll

see just how reactive.

The first surprise is
that this atom's life

didn't start on earth.

This particular atom
was born billions of

years ago, in a distant
corner of the galaxy.

The story begins
with a dying star.

The star has been
collapsing for more

than 10,000 years,
and at its core,

both temperature and
pressure have been rising.

Atoms squeeze together
creating ever bigger

ones, new elements
with new properties.

Every oxygen atom
is made this way.

Forged in the heart
of a dying star.

But this is the last
one this star will ever

make.

Because now it's making
larger and larger atoms

that are no longer
oxygen atoms,

until it runs
out of fuel.

Finally the core of
the star implodes,

then explodes.

A supernova.

All of the star's
atoms blast across the

universe.

But in the vastness
of space it's alone.

The only time it will
exist as a single atom.

Eventually it
slows down,

combining with other
atoms to form molecules

that clump together,
forming tiny particles

of dust.

Gravity draws dust
particles into ever

bigger lumps, until 10
million years after the

supernova, planet
earth is born.

And the star's last
oxygen atom is here

combined with two
hydrogen atoms in a

molecule of H20.

Water.

Water in the atmosphere
condenses to create the

first oceans.

This is where
life begins.

At first just tiny
bacteria cells break

apart dissolved
chemicals to get their

energy.

But three and a half
billion years ago some

bacteria cells learn to
harness the power of

sunlight.

When sunlight
strikes these cells,

the energy passes along
a chain of chemicals

from one atom
to another,

until it is used to
build new cells,

a process called
"photosynthesis".

As it does so, water
molecules tear apart.

But an oxygen atom
can't exist alone so it

combines with another
unwanted oxygen atom

and creates a molecule
of oxygen gas.

Our last atom from the
dying star is half of

the first
molecule of O2.

This is a major
milestone in the

history of our planet.

Photosynthetic bacteria
produces more and more

oxygen.

But where does it go?

Not into the sea or
the atmosphere above.

Oxygen is so reactive
it's always looking for

new partners.

It isn't hard
to find one.

In the oceans,
volcanoes spew out

chemicals from deep
within the earth.

Among them is iron.

O2 loves it and
forms a new molecule.

But the new molecule
is soon torn apart.

Our last oxygen atom
is now part of a water

molecule while its
partner drops to the

ocean floor,
shackled to iron.

Planet earth is
rusting.

This ancient story is
recorded for posterity

in thick red bands
found in some rocks at

the bottom
of the ocean.

But iron ore is more
than just a stunningly

beautiful record of
earth's history.

Iron has shaped the
destiny of humanity.

Before iron is forged
into a hard metal,

it has to be released
from oxygen's grip.

It takes a lot of
energy to separate the

iron from the
oxygen atoms.

So iron ore is mixed
with limestone in a

blast furnace and
heated to more than

3,600 degrees
Fahrenheit,

hot enough to force
oxygen out and release

the pure molten iron.

Now the metal is forged
and put to work.

The attraction of
oxygen to iron is

incredibly strong.

And we can thank
three-and-a-half-billion

years of oxygen in
our oceans for the

availability
of iron today.

But billions of years
ago earth is undergoing

great change.

The more dry
land that forms,

the more iron-rich
volcanoes erupt above

water, creating
unfavorable conditions

for iron to
soak up oxygen.

These volcanoes are
much hotter than those

on the seabed.

They spew different
chemicals already bound

to each other in stable
compounds and immune to

reactions with oxygen.

So around two and a
half billion years ago,

oxygen gas builds up
in the atmosphere.

It's a disaster.

Global pollution worse
than any in our own

time.

For billions of years
life had consisted of

bacteria getting energy
from breaking down

sulphur compounds
in an oxygen-free

environment.

For these bacteria,
oxygen is a deadly

poison.

Humans depend on
oxygen to stay alive,

so it's hard to think
of it as toxic.

Yet it can destroy
delicate organic

molecules.

Oxygen gas produces
earth's first mass

extinction.

Some of those ancient
sulphur bacteria still

exist today, though
they are banished to

areas that oxygen
can't reach.

Extreme environments,
like these volcanic

pools in Yellowstone
National Park.

Two billion years ago,
our last oxygen atom is

half of an O2
molecule again,

and with a new partner.

As a gas it wreaks
havoc for most bacteria

alive at the time.

But this simple
molecule is a new

opportunity for some.

Any life that tolerates
O2 has a strong

advantage.

Breaking down organic
molecules with O2

releases 16 times more
energy than breaking

apart simple minerals.

This is a great success
for these new bacteria.

They're still
around today.

Millions of them inside
every cell of our

bodies.

Called "mitochondria",
they provide energy for

every complex
life form.

Around 2 billion years
ago life is hooked on

O2, and oxygen takes on
a major role in shaping

evolution.

In 1909, paleontologist
Charles Walcott is

working in the rocky
mountains of British

Columbia.

All summer he's been
collecting samples from

a rock formation called
the Burgess Shale.

These rocks are
ancient,

around 520 million
years old,

so he isn't expecting
more than a few small

simple fossils.

What he finds, and
then keeps finding,

is astonishing.

Narrator: Most common
among the fossils

Charles Walcott finds
in the Burgess Shale is

an intricate creature
he calls a "lace crab"

because it looks
so delicate.

But how did something
so complex evolve so

long ago?

It's possible that
O2 played a part.

Oxygen levels in the
atmosphere have varied

throughout history.

The lace crab's
ancestors lived through

a time of low oxygen.

Life had just become
dependent on O2 so this

was a disaster.

But lace crabs reveal
how their ancestors

survived.

Their bodies are in
segments and each

segment has a gill
to absorb oxygen.

In evolutionary terms,
it's simple to add new

segments and therefore
increase the number of

gills, allowing the animal
to absorb more O2.

When oxygen levels rise
again, they thrive.

Walcott names this
animal Marrella.

The rocks of the
Burgess Shale exhibit a

rich diverse ocean
teeming with animals

all as strange
as Marrella.

And nearly all of
them segmented.

Life now depends on O2.

Forced to adapt when
oxygen levels fall,

and exploding into new
forms when levels rise

again.

But 400 million
years ago,

there's another drop
in oxygen levels.

The animals that
survive use a trick as

clever as Marrella's.

They find another
source of O2.

Air.

There's always more
oxygen in air than in

water, so finding a
way to tap into oxygen

above the waterline
is a clever move.

And it's what
mudskippers do today.

When the amount of O2
in their swampy home

changes with the tide
they head for land and

gulp air, pushing it
against moist patches

in their mouths
to soak up oxygen.

Breathing air means
they can stay topside.

Mudskippers also
breathe through their

skin but it has to stay
wet to absorb oxygen.

Rolling in mud keeps
their skin moist.

The returning tide
brings oxygen-rich

water and predators.

Mudskippers need
somewhere to hide so

they dig burrows.

But the oxygen-depleted
incoming water doesn't

mix with the
oxygen-rich water in

the burrow.

O2 levels could drop so
low that the mudskipper

might suffocate.

These clever creatures
have a solution.

They hollow
out a chamber,

and fill it with air
pulled in through their

mouth, one
gulp at a time.

The air chamber is safe
from predators and

holds enough oxygen to
last until the tide

ebbs again.

Breathing air is a good
way to survive low

oxygen levels in water.

When O2 levels rise
again about 30 million

years later the first
animals leave the water

to walk on land.

And they find a world
rich with plants that

colonized the land long
before they arrived.

Plants not only
cover the land,

they have grown
enormous with ferns the

size of trees.

There are so many
plants they change the

atmosphere itself.

Countless large
green leaves,

all pumping out oxygen
gas for millions of

years.

These huge plants also
lock up carbon in their

massive stems
and roots.

Dead plants are buried
so quickly in the

swampy forests they
don't have time to rot.

All that carbon is
locked away as coal.

Carbon reacts with
oxygen to produce

carbon dioxide.

And since oxygen is
always looking for a

partner, with so much
carbon locked away,

oxygen levels
can keep rising.

This is a great
time for insects.

They breathe passively,
letting oxygen diffuse

into their tissues
through tiny tubes that

open down their sides.

The longer the tubes,
the slower oxygen is to

reach their tissues and
that limits the size of

insects.

But 300 million
years ago,

O2 levels are almost
double those of today.

Imagine a dragonfly
with a 3-foot wingspan,

just one effect of so
much oxygen in the

atmosphere.

And it's not only the
animal world that's

supercharged by
high oxygen levels.

There is
something else.

The northern and
southern lights.

They grace our skies in
vivid color with the

help of oxygen.

High in the atmosphere,
molecules of gas are

bombarded by charged
particles from the sun,

giving them a flash of
energy released again

as light.

If the charged
particles strike

oxygen, the light show
is a brilliant green.

When O2 made up 35%
of the atmosphere,

the auroras must have
been brighter and much

greener than
they are today.

But this doesn't last.

270 million years ago
O2 levels fall again to

just 12%.

So much carbon is
buried that carbon

dioxide levels crash.

Plants need carbon
dioxide to fuel

photosynthesis so
there's much less

oxygen released into
the atmosphere.

At the same time all of
earth's continents are

fused into a single
super-continent.

Cut off from
moist ocean air,

a vast desert forms
at the center.

It's the greatest
catastrophe the planet

has known.

The Permian extinction.

90% of all species die.

Low oxygen is one of
many causes that come

together to generate
this crisis.

Yet life always adapts.

After the great
extinction,

there are reptiles
similar to modern

lizards.

They ambush their prey,
running in sudden,

short bursts.

Like modern lizards, it
can't run and breathe

at the same time.

As one front leg moves
forward it squashes the

lung on the other side.

It has to stop to
get its breath back.

Basilisk lizards have
the same problem.

But they have a more
efficient way to move.

Running just on its
hind legs is faster and

doesn't squash
its lungs.

It's a small
improvement,

but if O2
levels plummet,

it could make all
the difference.

230 million years ago,
that advantage makes

one group very
successful.

The first dinosaurs
stood upright just as

O2 levels were
at their lowest.

When oxygen levels rise
again they are ready to

rule the world.

T-Rex lives at the
end of the dinosaurs'

reign.

O2 levels then were
lower than they are

today.

If T-Rex were
around now,

it would be even
more terrifying.

With a body tuned to
lower oxygen levels,

today's higher oxygen
levels would give T-Rex

a major boost.

Sophisticated dinosaurs
like T-Rex did more

than just separate
their arm movements

from their breathing.

They developed a
new lung system.

Our lungs suck in air,
remove the oxygen then

blow it out again.

But the T-Rex
has rigid lungs.

Air sacs around the
lungs suck in the air,

and the air is pumped
through the lungs in

one direction only.

This is 33% more
efficient than our way

of breathing.

Good thing T-Rex is
not around today!

Narrator: Remember
our oxygen atom?

The one forged in the
heart of a dying star

billions of years ago?

It can't exist alone so
it partners up and then

splits up.

But deep below these
mountains in earth's

crust, this oxygen
atom's first partner is

still trapped where it
fell billions of years

ago.

The partner atom is
locked inside a mineral

called corundum.

Corundum consists
of just oxygen and

aluminum formed under
heat and pressure in

molten magma.

But sometimes it gets
contaminated by other

elements, like
chromium,

creating the red
stones we call rubies.

Within reach of the
Himalayan Mountains,

rubies surface in the
rivers after rainfall.

Downstream, ruby
collectors are waiting.

Rubies have been
collected for thousands

of years.

From long before we
understood how they

were created, or that
they trapped atoms of

oxygen from
ancient times.

While the trapped atom
remains in the ruby its

old partner, our
last oxygen atom,

is on a much
wilder adventure.

As part of a water
molecule it's still

shaping life on earth.

We take water
for granted,

but it's an
extraordinary liquid.

Pond skaters
can bend water,

creating dimples in
the surface,

because the oxygen in
the water molecules is

greedy for electrons.

Oxygen tries to pull
negatively charged

electrons toward it,
making the oxygen part

of the molecule
slightly negative,

and the hydrogen part
slightly positive.

Since opposites
attract,

each water molecule is
drawn into a dance with

its neighbor.

Underwater, all the
forces cancel out.

At the surface, each
water molecule is

pulled downward,
creating a skin,

surface tension.

Strong enough for some
animals to live their

entire lives here.

To avoid breaking
the surface,

water skaters have
legs covered in water

repellent hairs that
need continuous

grooming.

For other animals the
surface film is lethal.

Small insects are held
fast by tiny electrical

charges on the
countless water

molecules.

When the fly struggles,
vibrations on the

surface give away its
position to the pond

skater.

Surface tension is so
strong it creates a

problem for creatures
underwater.

A diving bell spider
spins an underwater web

in the shape of a bell
and fills it with air.

To top up the chamber,
it must break through

the surface tension
to get more oxygen.

Then, the spider sits
in its own pocket of

air, waiting for prey.

The bell holds
the spider rigid,

helping the bubble
conserve oxygen.

When the pressure of
oxygen in the bell

drops, more diffuses
in from the water.

The bell is working
like a gill but it

still needs the spider
to top up the air

supply.

Some air-breathing
creatures live in

fast-flowing streams
where hightailing it to

the surface is
a real effort.

And then there's this
bug, aphelocheirus.

It doesn't need to reach
the surface at all.

Like the spider, it's
covered in an air bubble.

A bubble so thin we can
see it only with an

electron microscope.

A cutaway section of
the bug's body surface

shows thousands of tiny
hairs that trap a thin

air layer so rigidly
it can't collapse.

So oxygen in the water
is always diffusing

into the bubble
replacing that used by

the bug.

It's a true gill,
covering a large part

of the bug's body.

These water creatures
all owe their lives to

oxygen.

And in more
ways than one.

Oxygen plays a crucial
role in the formation

of ice.

As the temperature
drops,

the dance of water
molecules slows down

and they move
closer together,

making the water
more dense.

When it freezes the
molecules arrange

themselves in a lattice
and are farther apart

again.

So ice is less
dense than water.

And it floats.

That's good for the
animals living beneath.

Our oxygen atom is free
again with yet another

partner.

But it's about to
change once more as it

gets involved in
reactions at the other

end of the
temperature scale.

Narrator: Fire.

O2 combines with
elements from hot fuel.

So much heat is
released that electrons

in the fuel are
catapulted into

different orbitals,
then drop back,

releasing the
energy as light,

the glowing flame.

Fire is yet another way
that oxygen shaped life

on earth.

Humans have relied on
fire for over a million

years.

When we moved out
of Africa to colder

countries,
it was vital.

It kept us warm and
scared away predators.

And fire was a focus
for humans to get

together, developing
our social groups.

It even shaped
how we look.

Cooked food is softer
than raw food,

and is more nutritious.

Over time our
jaws got smaller,

and our brains
got bigger.

And we learned to use
fire to transform the

world.

It might seem strange
to set fire to the

forest that
provides food.

But early hunters
did just that.

Open glades supported
more grass,

feeding more prey.

And hunting was easier
with fewer trees in the

way.

Indigenous peoples
cleared the ground for

crops with fire,
leaving rich,

fertile soils.

And communities grew
larger and more

elaborate on the
back of farming.

Fire was part of
the human toolkit.

That last atom from the
burning star helped

people hunt, and went
on to play a part in

the birth of
civilization.

Dyeing fabric in exotic
colors has a long

cultural history.

But one dye is
stranger than most.

Cloth dyed in indigo
comes out the same

color as it went in.

But hang it out to dry,
and something strange

happens.

In water, the dye
appears colorless as it

soaks into the cloth.

In air, the dye
reacts with oxygen.

And after 10 minutes,
the fabric changes

color.

A Babylonian stone
tablet from 600bc

contains instructions
for dyeing cloth with

indigo.

It stresses the
importance of repeating

the dyeing and drying
process many times to

get a deep color.

The process took a lot
of effort and made

indigo fabric
quite valuable.

Today equipment
is different,

and designs are
more ambitious.

But the real work is
still done by oxygen.

For such a
reactive element,

that original partner
atom has led a quiet

life trapped in a ruby.

But not for much
longer.

Thanks to an 18th
century emperor.

Narrator: Precious and
semi-precious stones

fascinate Austrian
emperor Franz Stefan.

He relinquishes some of
his vast collection in

the name of science.

Could diamonds be
melted together to make

a huge priceless one?

He puts some small
diamonds into a dish,

then uses a reflector
and powerful magnifying

glass to focus heat
where they touched.

Was this smoke a
sign it was working?

No.

The smoke is
carbon dioxide,

one carbon atom
and 2 oxygen atoms,

released as the emperor
vaporizes his diamonds.

Melting rubies would
have been quite an

effort.

They must be
heated to 4,000

degrees Fahrenheit
to melt.

The most the emperor
could do is free a few

atoms on the
ruby's surface.

But the original
partner atom is now

free at last thanks to
the vaporized diamonds.

A few years
later, in Paris,

Antoine Lavoisier
understands the

mechanism of burning
better than Franz

Stefan.

He realizes that oxygen
is the gas responsible

for fire and the
substance we need to

breathe.

Fire and breathing
have a lot in common.

Both involve oxygen,
release energy and

create carbon dioxide.

Respiration is just our
body slowly burning

sugars.

It's a huge step
forward for chemistry.

The Lavoisiers know
that breathing O2 is

pleasant.

They couldn't have
known they were

starting a trend.

In the 1990s a craze
for oxygen bars starts

in Japan, and spreads
to California.

Customers pay to
breathe in 92% oxygen

for 20 minutes.

Combining the
experience with

aromatherapy gives a
choice of flavors of

oxygen.

Each jar contains an
inconceivable number of

oxygen molecules: 10 with
22 zeroes after it.

So many that every jar
is highly certain to

contain an oxygen atom
breathed in by Genghis Khan.

The 800 years between
us and Genghis Khan

seems like a long time,
but to an oxygen atom

it's a mere blink.

Breathing in
concentrated O2 is

thought to increase
stamina and energy

levels.

Not surprising when you
realize these people

are breathing
in rocket fuel.

The space shuttle burns
liquid hydrogen to

propel it into space.

To get the most energy,
the hydrogen fuel is

burned with
liquid oxygen.

Powerful
but clean fuel,

generating only water
as an end product.

Two minutes after
takeoff, 28 miles up,

and the rockets
are jettisoned.

But our last oxygen
atom is in a molecule

that doesn't react
with hydrogen.

Drifting in the upper
atmosphere it's struck

by UV rays, and
receives enough energy

to split apart and join
a new O2 molecule.

The original partners
are finally together

again.

This time as O3, ozone.

Ozone creates a shield,
blocking lethal

radiation from the sun
and protecting life

below.

The ozone layer first
formed three billion

years ago as O2, made
by the first plants,

rose high enough to
intercept the sun's UV rays.

If life hadn't produced
O2 early enough the

planet would have
been uninhabitable,

bombarded by deadly
ultraviolet rays.

This is the story of
how life was made possible.

The story of the
paradox that is oxygen.

Lethal, volatile
and destructive.