Nova (1974–…): Season 35, Episode 1 - Absolute Zero: The Conquest of Cold - full transcript

Text : WTC-SWE

(male narrator) The greatest
triumph of civilization

is often seen as
our mastery of heat.

Yet our conquest of cold
is an equally epic journey,

from dark beginnings,
to an ultra cool frontier.

For centuries, cold
remained a perplexing mystery

with no obvious
practical benefits.

Yet in the last 100 years,

cold has transformed
the way we live and work.

Imagine supermarkets
without refrigeration,

skyscrapers
without air-conditioning,



hospitals without MRI machines
and liquid oxygen.

We take for granted
the technology of cold,

yet it has enabled us
to explore outer space

and the inner depths
of our brain.

And as we develop new
ultra cold technology

to create quantum computers
and high-speed networks,

it will change
the way we work and interact.

How did we harness something

once considered to fearsome
to even investigate?

How have scientists and dreamers
over the past four centuries

plunged lower and lower
down the temperature scale

to conquer the cold
and reach its ultimate limit?

A Holy Grail as elusive
as the speed limit of light--

"Absolute Zero,"
up next on "NOVA."



(narrator)
Extreme cold has always held

a special place
in our imagination.

For thousands of years, it
seemed like a malevolent force

associated with death
and darkness.

Cold was
an unexplained phenomenon.

Was it a substance, a process,
or some special state of being?

Back in the 17th century,
no one knew,

but they certainly
felt its effects

in the freezing London winters.

(Simon Schaffer)
17th-century England
was in the middle

of what's now called
"the little Ice Age."

It was fantastically cold
by modern standards.

You have to imagine
a world lit by fire

in which most people are
cold most of the time.

Cold would've felt
like a real presence,

a kind of positive agent that
was affecting how people felt.

(narrator)
Back then, people
felt at the mercy of cold.

This was a time
when such natural forces

were viewed with awe
as acts of God.

So anyone attempting to tamper
with cold did so at his peril.

The first to try was an
alchemist, Cornelius Drebbel.

On a hot summer's day in 1620,

King James I and his entourage

arrived to experience
an unearthly event.

Drebbel, who was also
the court magician,

had a wager with the King

that he could turn summer
into winter.

He would attempt
to chill the air

in the largest interior space
in the British Isles,

the great hall of Westminster.

[orchestra plays]

Drebbel hoped
to shake the King to his core.

(Andrew Szydlo)
He had a phenomenally
fertile mind.

He was an inventor
par excellence.

His whole world was steeped

in the world of alchemy,

of perpetual motion machines,

of the idea of time, space,

planets, moon, sun, gods.

He was a fvently religious
man.

He was a person
for whom nature presented

a phenomenal--
a galaxy of possibilities.

Dr. Andrew Szydlo, a chemist

with a lifelong fascination
for Drebbel,

enjoys his reincarnation
as the great court magician.

Like most alchemists, Drebbel
kept his method secret.

Dr. Szydlo wants
to test his ideas

on how Drebbel created
artificial cold.

When Drebbel was
trying to achieve

the lowest temperature possible,
he knew that ice, of course,

was the freezing point, or the
coldest you could get normally.

But he would've been
aware of the facts

through his experience that
mixing ice with different salts

could get you
a colder temperature.

(narrator)
Salt will lower the temperature
at which ice melts.

Dr. Szydlo thinks Drebbel
probably used common table salt,

which gives
the biggest temperature drop.

But salt and ice alone
would not be enough

to cool the air
within such a large interior.

Drebbel was famous for designing
elaborate contraptions,

a passion shared by Dr. Szydlo,

who has an idea
for the alchemist's machine.

So here, we would've
had a fan,

which would've been
turned over

blowing warm air
over the cold vessels there,

and as the air blows
over these cold jars,

we would've had, in effect,

the world's first
air-conditioning unit.

(narrator)
But could this really
turn summer into winter?

(Dr. Szydlo)
The idea was to stir it in
as well as possible

in the 5 seconds
that you have to do it.

(narrator)
Dr. Szydlo stacks
the jars of freezing mixture

to create cold corridors
for the air to pass through.

We can feel
it's very cold,

and the fact
I could feel cold air

actually falling on my hands,

because cold air, of course,
is denser than warm air,

and one can feel it
quite clearly on the fingers.

[squeaking]

(narrator)
The vital question:

would the gust of warm air
become cold?

I can feel certainly
a blast of cold air hitting

as that 2nd cover
was released.

Well, temperature,
we're on 14 at the moment.

Yes, keep it going.

That's definitely
the right direction.

(narrator)
King James would've been shaken

by his encounter
with man-made cold.

Had Drebbel written up
his great stunt,

he might've gone down in history

as the inventor
of air-conditioning.

Yet it would be
almost 3 centuries

before this idea
would actually take off.

To advance knowledge
and conquer the cold

required
a very different approach--

the scientific method.

The fundamental question,
"What is cold?"

haunted Robert Boyle
nearly 50 years later.

The son of the Earl of Cork,
a wealthy nobleman,

Boyle used his fortune to build
an extensive laboratory.

Boyle is famous
for his experiments

on the nature of air,

but he also became
the first master of cold.

Believing it to be an important,
but neglected subject,

he carried out
hundreds of experiments.

(Simon Schaffer)
He worked through
very systematically

a series of ideas
about what cold is.

Does it come from the air?

Does it come
from the absence of light?

Is it that
there are strange,

so-called "frigoric"
cold-making particles?

(narrator)
In Boyle's day,
the dominant view was

that cold is a primordial
substance that bodies take in

as they get colder
and expel as they warm up.

It was this view that Boyle
would eventually overturn

by a set of carefully devised
experiments on water.

First, he carefully weighed
a barrel of water

and took it outside in the snow,
leaving it to freeze overnight.

Boyle was curious
about the way water expanded

when it turned to ice.

He reasoned that if once
the water turned to ice,

the barrel weighed more,

then perhaps cold was
a substance after all.

But when they reweighed
the barrel,

they discovered
it weighed exactly the same.

(Simon Schaffer)
So what must be happening,
Boyle guessed,

was that the particles of water
were moving further apart,

and that was the expansion,
not some substance

flowing into the barrel
from outside.

(narrator)
Boyle was becoming
increasingly convinced

that cold was not a substance,

but something
that was happening

to individual particles,
and he began to think back

to his earlier experiments
with air.

As matter like air becomes
warmer, it tends to expand.

Boyle imagined the air particles
were like tiny springs,

gradually unwinding and taking
up more space as they heat up.

(Simon Schaffer)
Boyle's conclusion here was

that heat is a form of motion
of a particular kind

and that as bodies cool down,
they move less and less.

(narrator)
Boyle's longest-published book
was on the cold;

yet he found
its study troublesome

and full of hardships, declaring
that he felt like a physician

trying to work
in a remote country

without the benefit
of instruments or medicines.

To properly explore
this country of the cold,

Boyle lamented the lack
of a vital tool,

an accurate thermometer.

[harpsichord & strings play]

(narrator)
It was not until
the mid-17th century,

that glassblowers in Florence

began to produce accurately
calibrated thermometers.

Now it became possible to
measure degrees of hot and cold.

Like the air
in Boyle's experiment,

heat makes
most substances expand.

Early thermometers used alcohol,
which is lighter than Mercury

and expands much more with heat.

So these Florentine thermometers
were sometimes

several meters long
and often wound into spirals.

But there was still one major
problem with all thermometers,

the lack of a universally
accepted temperature scale.

There are all kinds
of different ways

of trying to stick numbers to
these degrees of hot and cold,

and they, on the whole, didn't
agree with each other at all.

So one guy in Florence makes
one kind of thermometer,

another guy in London
makes a different kind,

and they just don't even
have the same scale,

and so there was
a lot of problem

in trying to standardize
thermometers.

(narrator)
The challenge was
to find events in nature

that always occur
at the same temperature

and make them fixed points.

At the lower end of the scale,

that might be ice
just as it begins to melt.

At the upper end, it could be

wax heated to its melting point.

The first temperature scale

to be widely adopted was devised
by Gabriel Daniel Fahrenheit,

a gifted instrument maker
who made thermometers

for scientists and physicians
across Europe.

He had several fixed points.

He used a mixture of ice, water,
and salt for his 0 degrees;

ice melting in water
at 32 degrees;

and for his upper fixed point,

the temperature
of the human body at 96 degrees,

which is close
to the modern value.

One of the things that
Fahrenheit was able to achieve

was to make thermometers
quite small,

and that he did
by using mercury

as opposed to alcohol or air,
which other people had used.

And because mercury
thermometers are compact,

clearly if you're trying to use
it for clinical purposes,

you don't want some big thing
sticking out of the patient!

So the fact that he could make
them small and convenient,

that seems to be what made

Fahrenheit so famous
and so influential.

(narrator)
It was a Swedish astronomer,
Anders Celsius,

who came up with the idea
of dividing the scale

between 2 fixed points
into 100 divisions.

The original scale used
by Celsius was upside down,

so he had the boiling point
of water as zero

and the freezing point as 100,

with numbers just
continuing to increase

as we go below freezing.

And this is
another little mystery

in the history
of the thermometer

that we just don't know
for sure.

What was he thinking
when he labeled it this way?

And it was
the botanist Linnaeus,

who was then the president
of the Swedish Academy,

who after a few years said,
"We need to stop this nonsense,"

and inverted the scale

to give us what we now call
"Celsius scale" today.

(narrator)
A question nobody thought to ask

when devising temperature scales
was, how low can you go?

Is there an absolute lower limit
of temperature?

The idea that there might be

would become a turning point
in the history of cold.

(Hasok Chang)
The story begins with the French
physicist Guillaume Amontons.

He was doing experiments heating
and cooling bodies of air

to see how they expand
and contract.

(narrator)
Amontons heated air
in a glass bulb

by placing it in hot water.

Just like a hot air balloon

the air in
the glass bulb expanded

as the increased pressure forced
a column of mercury up the tube.

Then he tried cooling the air.

(Hasok Chang)
He was noticing that, well,

when you cool a body of air,
the pressure would go down.

And he speculated, well,

what would happen
if we just kept cooling it?

(narrator)
By plotting this falling
temperature against pressure,

Amontons saw that
as the temperature dropped,

so did the pressure, and this
gave him an extraordinary idea.

Amontons started to
consider the possibility,

what would happen if you
projected this line back

until the pressure was zero?

And this was the first time
in the course of history

that people have
actually considered

the concept of an absolute zero
of temperature.

Zero pressure;
zero temperature.

It was quite the revolutionary
idea when you think about it

because you wouldn't just think

that temperature has
a limit of lower bound, or zero,

because in the upper end,
it can go on forever,

we think, until it's hotter
and hotter and hotter.

But somehow, maybe there's

a zero point
where this all begins,

so you could actually
give a calculation

of where this zero point
would be.

Amontons didn't do that
calculation himself,

but some other people did
later on, and when you do it,

you get a value that's actually
not that far

from the modern value
of roughly minus 273 centigrade.

(narrator)
In one stroke,
Amontons had realized

that although temperatures
might go on rising forever,

they could only fall
as far as this absolute point,

now known to be
minus 273 degrees centigrade.

For him, this was
a theoretical limit,

not a goal to attempt to reach.

Before scientists could venture
towards this zero point,

far beyond the coldest
temperatures on Earth,

they needed to resolve
a fundamental question.

By now,
most scientists defined cold

simply as the absence of heat.

But what was actually happening

as substances warmed or cooled
was still hotly debated.

The argument of men
like Amontons

relied completely on the idea
that heat is a form of motion,

and that particles move
more and more closely together

as the substance
in which they're in

gets cooler and cooler.

(narrator)
Unfortunately,
the science of cold

was about to suffer
a serious setback.

The idea that cooling was caused

by particles slowing down
began to go out of fashion.

At the end of the 18th century,

a rival theory
of heat and cold emerged

that was tantalizing appealing,
but completely wrong.

It was called
"The Caloric Theory,"

and its principal advocate

was the great French chemist
Antoine Lavoisier.

Like most scientists
at the time,

Lavoisier was a rich aristocrat
who funded his own research.

He and his wife,
Madame Lavoisier,

who assisted
with his experiments,

even commissioned
the celebrated painter David

to paint their portrait.

Lavoisier
carried out experiments

to support the erroneous idea
that heat was a substance,

a weightless fluid
that he called "caloric."

He thought that in
the solid state of matter,

molecules were just
packed close in together,

and when you added more
and more caloric to this,

the caloric would
insinuate itself

between these particles
of matter and loosen them up.

So the basic notion was
that caloric was this fluid

that was, as he put it,
"self-repulsive."

It just tended to break things
apart from each other.

And that's
his basic notion of heat;

as cold is just
the absence of caloric,

or the relative lack
of caloric.

(narrator)
Lavoisier even had an apparatus
to measure caloric,

which he called a "calorimeter."

He packed the outer compartment
with ice.

Inside, he conducted experiments
that generated heat;

sometimes
from chemical reactions,

sometimes from animals

to determine how much caloric
was released.

He collected the water
from the melting ice

and weighed it to calculate

the amount of caloric
generated from each source.

(Robert Fox)
I think the most striking thing
about Lavoisier

is that he sees caloric
as a substance

which is exactly comparable
with ordinary matter,

to the point
that he includes caloric

in his list of the elements.

(Simon Schaffer)
Indeed, for Lavoisier,

it's an element
like oxygen or nitrogen.

Oxygen gas is made
of oxygen plus caloric,

and if you take
the caloric away,

presumably the oxygen
might liquefy.

That's a very hard model
to shift

because it explains so much,

and indeed,
Lavoisier's chemistry

was so otherwise
extraordinarily successful.

However, Lavoisier's story about
caloric was soon undermined.

(narrator)
But there was one man who was
convinced Lavoisier was wrong

and was determined to destroy
the caloric theory.

His name was Count Rumford.

Count Rumford had
a colorful past.

He was born in America,

spied for the British
during the Revolution,

and after being forced
into exile

became an influential
government minister in Bavaria.

[loud BOOM!]

Among his varied
responsibilities

was the artillery works,
and it was here in the 1790s

that he began to think
about how he might be able

to disprove the caloric theory
using cannon boring.

Rumford had noticed
that the friction

from boring out a cannon barrel
generated a lot of heat.

He decided to carry out
experiments to measure how much.

He adapted the machine
to produce even more heat

by installing a blunt borer

that had one end submerged
in a jacket of water.

As the cannon turned
against the borer,

the temperature of the water
increased and eventually boiled.

The longer he bored,
the more heat was produced.

For Rumford, what
this showed was

that heat must be
a form of motion,

and heat is
not a substance,

because you could generate

indefinitely large
amounts of heat

simply by turning
the cannon.

(narrator)
Despite Count Rumford's
best efforts,

Lavoisier's caloric theory
remained dominant

until the end
of the 18th-century.

His prestige as a chemist

meant that few dared
challenge his ideas,

but this did not protect him

from the revolutionary turmoil
in France,

which was about to interrupt
his research.

At the height
of the reign of terror,

Lavoisier was arrested
and eventually lost his head.

Once he was guillotined,
his wife left France

and eventually met Rumford

when he moved to Western Europe
in the early 1800s.

Rumford then married her.

So he'd married the widow
of the man

who founded the theory
that heat destroyed.

(narrator)
The marriage was short-lived.

After a tormented year,
Rumford left Madame Lavoisier

and devoted the rest of his
life to his first love, science.

It would be nearly 50 years

before Rumford's idea
that temperature is

simply a measure of the movement
of particles was accepted.

With heat, the particles,
what we now know as atoms,

speed up, and with cold,
they slow down.

Rumford's dedication
to science led him to become

a founder of the Royal
Institution in London,

and it was here that
the next major breakthrough

in the conquest of cold
would occur.

Michael Faraday,
who later became famous

for his work
on electricity and magnetism

would take
a critical early step

in the long descent
towards absolute zero

when he was asked to investigate
the properties of chlorine

using crystals
of chlorine hydrate.

This experiment was
potentially explosive,

which is perhaps
why it was left to Faraday

and perhaps also
why Dr. Andrew Szydlo

is curious to repeat it today.

We are about
to undertake

an exceedingly dangerous
experiment

in which Michael Faraday in 1823
heated this substance here,

the hydrates of chlorine,
in a sealed tube.

Is that sealed?

(man)
That's sealed, Andrew.

(Andrew)
That's absolutely brilliant!

(narrator)
In the original experiment,

Faraday took the sealed tube
and heated the end

containing the chlorine hydrate
in hot water.

He put the other end
in an ice bath.

Soon he noticed yellow
chlorine gas being given off.

(Andrew)
Because the gas
is being produced,

pressure's building up.

Ray, this is where it starts
to get dangerous,

so if you'll now take
a few steps back.

(narrator)
When Faraday did the experiment,
a visitor, Dr. Paris,

came by to see
what he was up to.

Paris pointed out
some oily matter

in the bottom of the tube.

Faraday was curious and decided
to break open the tube.

Right, so let's have
a look inside here.

[ping!]

(narrator)
The explosion sent
shards of glass flying.

With the sudden release
of pressure,

the oily liquid vanished.

[ping!]

And there we are.
Is that what happened?

That's exactly
what happened.

It popped open,
glass flew.

And can you detect

the strong smell
of chlorine? I can now.

Absolutely. Well, he detected
the strong smell of chlorine,

and this was
a major mystery for him.

(narrator)
Faraday soon realized
the increased pressure

inside the sealed tube
had caused the gas to liquefy...

and when the tube was broken,
the oily liquid evaporated.

Just as heat must be applied
to evaporate water,

he saw that energy
from the surrounding air

had transformed liquid chlorine
into a gas.

In a brilliant deduction,
Faraday realized

that by absorbing heat
from the air,

he had cooled, or refrigerated,
the surroundings.

Michael Faraday
had produced cold!

Later, he used the same
technique with ammonia,

which absorbs even more heat.

He predicted that one day

this cooling might be
commercially useful.

Faraday took no interest in
commercial exploitation...

but across the Atlantic,

a Yankee entrepreneur had
a very different philosophy.

Frederic Tudor had a chance
conversation with his brother

that led him on a path

to become one of the richest men
in America.

(Dennis Picard)
The story goes,
at the dinner table

they were trying to decide what
they had on their father's farm

they could make money off of.

And certainly there was
a lot of rocks,

but people weren't going
to pay for that,

so they came up
with the idea of maybe ice,

'cause some areas
did not have ice.

And it seemed kind of crazy
at first, but it paid off.

(narrator)
When Tudor began harvesting ice
from New England ponds,

he soon realized he needed
specialized tools

to keep up
with the huge demand.

(Dennis Picard)
We had the saws,

and the saws were an improvement
over the old wood saws.

They have teeth that are
sharpened on both sides

and set, so it cuts on both
the up and the down stroke.

The crew could clear
a 3-acre pond easily

in a couple of days.

(narrator)
Tudor's dream to make ice
available to all

was not confined to New England.

He wanted to ship ice
to hot parts of the world

like the Caribbean
and the deep South.

(Dennis Picard)
When Tudor first tried
to convince shipmasters

to put his load
of frozen water into the ships,

they all refused,
'cause they told him

that water belonged
outside the hull, not inside.

So he had to go find other
investors to get the money

to buy his own ship,
and he bought a ship

by the name of the "Favorite."

(narrator)
New England became the
refrigerator for the world

with ice shipments
to the Caribbean,

the coast of South America
and Europe.

Tudor even reached
India and China.

Watching the ice cutters
working Walden Pond,

Henry Thoreau marveled that
water from his bathing beach

was traveling
halfway around the globe

to end up in the cup
of an East Indian philosopher.

Tudor, who soon became known
as the "Ice King,"

began using horses and huge
teams of workers to harvest

larger and larger lakes
as the demand for ice grew.

During the latter half of the
19th century, the ice industry

eventually employed
tens of thousands of people.

(Dennis Picard)
Tudor became the largest
distributor of ice,

and he became one of the first
American millionaires.

And we're talking about
one of his ships

going to the Caribbean
giving him a profit of $6,000!

Now, this is in a time period
when people were earning

$200 to $300 a year,
the average family.

So someone earning thousands of
dollars was just inconceivable,

and that would be losing 20%

of your ice when it got there.

There was still
huge amounts of profit.

(narrator)
Tudor's success was based

on an extraordinary
physical property of ice.

It takes the same amount of heat
to melt a block of ice

as it does to heat an equivalent
quantity of water

to around 80 degrees Celsius.

This meant that ice took
a long time to melt,

even when shipped
to hotter climates.

What started out as
a small family enterprise

turned into a global business.

Frederic Tudor had
industrialized cold

in the same way

the great pioneers of steam
had harnessed heat.

[hissing]

By the 1830s, the Industrial
Revolution was in full swing.

Yet ironically, it was not until
a small group of scientists

worked out
the underlying principles

of how steam engines
convert heat into motion

that the next step in the
conquest of cold could be made.

Only after solving
this riddle of heat engines

could the first
cold engines be made

to produce
artificial refrigeration.

How much useful work

can you get out of
a given amount of heat?

By the early 1800s,
that had become

the single most important
economic problem in Europe.

To make a profit was
to convert heat into motion--

efficiently--
without wasting heat

and getting the maximum
amount of mechanical effect.

[creaking of gears]

(narrator)
The first person to really
engage with this problem

was a young French artillery
engineer, Sadi Carnot.

He thought that improving
the efficiency of steam engines

might help France's
flagging economy

after defeat at Waterloo
in 1815.

Working at the Conservatoire
des Arts et M?tiers,

he began to analyze
how a steam engine

was able to turn heat
into mechanical work.

In steam engines,
it looks as though

heat is flowing
around the engine,

and as it flows, the engine
does mechanical work.

The implication there is

that heat is neither
consumed nor destroyed.

You simply circulate it around,
and it does work.

(narrator)
Carnot likened this flow of heat

to the flow of water
over a waterwheel.

He saw that the amount of
mechanical work produced

depended on how far
the water fell.

His novel idea was that steam
engines worked in a similar way,

except this fall was
a fall in temperature

from the hottest to the coldest
part of the engine.

The greater
the temperature difference,

the more work was produced.

Carnot distilled
these profound ideas

into an accessible book
for general readers,

which meant it was
largely ignored by scientists

instead of being heralded
as a classic.

Well, this is the book.

It's Carnot's
only publication.

"Reflections on the Motive Power
of Fire" of 1824,

a small book, 118 pages only,

published just 600 copies,

and in his own lifetime,
it's virtually unknown.

Twenty years
after the publication,

William Thompson,
the Scottish physicist,

is absolutely intent
on finding a copy.

He's here in Paris,
and the accounts we have suggest

that he spends
a great deal of time

visiting bookshops,
visiting the bouquinistes

on the banks of the Seine

looking, always asking
for the book,

and the booksellers tell him
they've never even heard of it.

(narrator)
William Thompson, who would
later become Lord Kelvin,

a giant in this new field
of thermodynamics,

was impressed by Carnot's idea
that the movement of heat

produced useful work
in the machine.

But when he returned home,

he heard about
an alternative theory

from a Manchester brewer
called James Joule.

Joule had this notion
that Carnot was wrong,

that heat wasn't producing work
just by its movement.

Heat was actually turning
into mechanical work,

which is a very strange idea
when you think about it.

We're all now used to
thinking about energy

and how it can take
all different forms,

but it was
a revolutionary idea

that heat and something
like mechanical energy

were, at bottom,
the same kind of thing.

(narrator)
The experiment
that convinced Joule of this

was set up in the cellar
of his brewery.

It converted
mechanical movement into heat,

almost like a steam engine
in reverse.

He used falling weights

to drive paddles
around the drum of water.

The friction from this process

generated
a minute amount of heat.

Only brewers had
thermometers accurate enough

to register
this tiny temperature increase

caused by a measured amount
of mechanical work.

Joules' work mattered
because it was the first time

that anyone had
convincingly measured

the exchange rate
between movement and heat.

He proved the existence
of something

that converts
between heat and motion.

That something was going
to be called "energy,"

and it's for that reason
that the basic unit of energy

in the new International
System of Units

is named after him,
"The Joule".

(narrator)
Joule and Carnot's ideas
were combined by Thomson

to produce
what would later be known

as "the laws of thermodynamics."

The first law,
from Joule's work, states

that, "Energy can be converted
from one form to another,

but can never be
created or destroyed."

The 2nd law, from Carnot's
theory, states that,

"Heat flows in one direction
only, from hot to cold."

In the 2nd half
of the 19th century,

this new understanding paved
the way for steam power

to artificially produce ice.

Ice-making machines
like this one

were based on principles
discovered by Michael Faraday,

who showed when ammonia changes
from a liquid to a gas,

it absorbs heat
from its surroundings.

It's part of what is now known
as a "refrigeration cycle."

In the first stage
of this cycle,

gigantic pistons compress
ammonia gas into a hot liquid.

The hot liquefied ammonia is
pumped into condenser coils

where it's cooled...

and fed into pipes
beneath giant water tanks.

Then the pressure is released

and the liquid ammonia
evaporates,

absorbing heat
from the surrounding water.

Gradually, the tanks of water
become blocks of ice.

By the 1880's,
many towns across America

had ice plants like this one,

which could produce
150 tons of ice a day.

For the first time,
artificially produced ice

was threatening the natural
ice trade

created by Frederic Tudor.

America's appetite for ice was
insatiable.

Slaughterhouses, breweries,

and food warehouses
all needed ice.

Animals were disassembled
on production lines in Chicago,

and the meat was loaded
into ice-cooled boxcars

to be shipped by railroad.

(man)
Livestock on its way

to the great meat-packing
centers of the nation,

to markets everywhere.

Food of every sort

safely and quickly delivered
in refrigerator cars.

(narrator)
As fruit and vegetables became
available out of season,

urban diets improved,
making city dwellers

the best-fed people
in the world.

And to keep everything
fresh at home,

the iceman made
his weekly delivery

to recharge the refrigerator.

(Tom Schachtman)
Refrigeration makes a tremendous
difference in people's lives.

First of all,
in the diet,

what is possible
for them to eat.

They can go to the store
once a week.

They don't have
to go every day.

They can obtain
at that store

foods that are from almost
anywhere in the world

that have been transported
and kept cool,

and then they can keep them
in their own home.

(narrator)
Eventually
the iceman disappeared

as more and more households
bought electric refrigerators.

These used
the same basic principles

as the old ice-making machines.

Liquid ammonia circulating
in pipes evaporates,

draining the heat
away from the food inside.

Compressed by an electric pump,

the gas is condensed
back into liquid ammonia,

and the cycle begins again.

The electric power companies
loved refrigerators

because they ran
all day and all night.

They may not have used
that much power for each hour,

but they continued
to use that.

So one of the ways that they
sold rural electrification

was the possibility of having
your own refrigerator.

(narrator)
In the early days,

the freezer was used
to freeze water, nothing else.

Freezing was seen as having

the same damaging effects
as frost.

[wind howls]

The man who would change
this idea forever

was a scientist and explorer
named Clarence Birdseye.

In 1912, Birdseye set off

on an expedition to Labrador,

and the temperature dropped
to 40 degrees below freezing.

The Inuit had taught Birdseye

how to ice fish

by cutting a hole in the ice
several feet thick.

When he caught a fish,

he found it froze almost
as soon as it hit the air.

This process seemed to preserve
the fish in a unique way.

(Tom Schachtman)
When you went to cook this fish,

it tasted just as good
as if fresh,

and he couldn't
figure that out,

because when he
froze fish at home,

they would taste terrible.

So when he got back home,

he finally tried to figure out
what was the difference

between the quick freezing
and the usual freezing.

(narrator)
Under closer examination,

he could see what was happening
to the fish cells.

With slow freezing,
large ice crystals formed,

which distorted
and ruptured the cells.

When thawed,
the tissue collapsed

and all the nutrients
and flavor washed away--

the so-called
"mushy strawberry" syndrome.

But with fast freezing,

only tiny ice crystals were
formed inside the cells,

and these caused little damage.

It was all down to the speed
of the freezing process.

A simple concept,
but it took Clarence Birdseye

another 10 years to perfect

a commercial
fast-freezing technique that

would mimic the natural process
he'd experienced in Labrador.

In 1924, he opened
a flash freezing plant

in Gloucester, Massachusetts

that froze freshly landed fish
at minus 45 degrees.

He then extended that to all
sorts of other kinds of meats

and produce and vegetables
and almost single-handedly

invented
the frozen food industry.

(narrator)
Refrigerators and freezers

would eventually become
icons of modern living,

but there was a less visible
cold transformation

happening at the same time.

This would also have
a huge impact on urban life--

the cooling of the air itself.

Three centuries had passed
since Cornelius Drebbel

had shaken King James
in Westminster.

Now at the dawn
of the 20th century,

air cooling was about
to shake the world.

Tell me, what is the low down
on this air-conditioning thing?

Now you've started something
by asking me that.

(narrator)
Air-conditioning was about
to transform modern life,

and the person largely
responsible was Willis Carrier,

who started off working
for a company that made fans.

(Marsha Ackermann)
Carrier is sent to Brooklyn
for a very special job in 1902.

The company that publishes
the magazine "Judge,"

one of the most popular
full-color magazines in America

at this particular time,
is having a huge problem.

It's July in Brooklyn
and the ink which they use

on their beautiful covers
is sliding off the pages.

It will not stick because
the humidity is too high.

Carrier, using some principles
that he's been developing

as a young new employee of
this fan company, finds a way

to get out the July 1902
run of the "Judge" magazine,

and from there he begins

to eventually build his
air-conditioning empire.

(narrator)
It's based
on a simple principle.

(man)
Control of humidity through
control of temperature--

that was Willis Carrier's idea.

(narrator)
He used refrigeration

to cool the water vapor
in the humid air.

The vapor condensed
into droplets,

leaving the air dry and cool.

The demand for air-conditioning
gradually grew.

In the 1920's, movie houses were

among the first
to promote the benefits.

People would flock there
in summer to escape the heat.

(Marsha Ackermann)
The movies are wildly popular,
and the air-conditioning

certainly helps
to attract an audience,

especially if they happen
to be walking down the street

on a horribly hot day and they
duck into this movie theater

and have this wonderful
experience.

(narrator)
Air-conditioning became
increasingly common

in the workplace too,

particularly in the South where
textile and tobacco factories

were almost unbearable
without cooling.

(man)
When employees breath good air
and feel comfortable,

they work faster
and do a better job.

I think
some people think

these were nice
compassionate employers

who were cooling down the
workplace for the workers,

but of course, nothing could be
further from the truth.

That was
an inadvertent by-product,

but actually this was
a quality control device

to control the breaking
of fibers in cotton mills

to get consistent
quality control

in these various industries

to control the dust
that had bedeviled

tobacco stemming room workers
for decades.

I mean, I think the workers
obviously went home

and to their unair-conditioned
shacks in most cases

and talked about
how nice and cool

it was working
during the day.

It's silly to suffer
from the heat

when you can afford the modest
cost of air-conditioning.

(narrator)
By the 1950's, people were
air-conditioning their homes

with stand-alone window units
that could be easily installed.

This wasn't just an appliance;

it offered
a new, cool way of life.

[big band plays swing]

(Raymond Arsenault)
Walking down a typical
Southern street

prior to the air-conditioning
revolution,

you would have seen families,
individuals, outside.

They would have been
on their porches,

on each other's porches.

There was a visiting tradition,
a real sense of community.

[electric compressor
fan motors start; fans whirr]

Well, I think all that changes
with air-conditioning.

You walk down that same street
and basically what you'll hear

are not the voices of people
talking on the porch;

you'll hear the whirr
of the compressors.

Guess what we've got!

An RCA room air conditioner.

I'm a woman, and I know how much
pure air means to mother

in keeping our rooms clean
and free from dust and dirt.

(narrator)
Control of the cold has
transformed city life.

Refrigeration helped cities
expand outwards

by enabling large numbers
of people

to live at great distances
from their source of food.

Air-conditioning enabled cities
to expand upwards.

Beyond 20 stories, high winds
make open windows impractical,

but with air-conditioning,

100-story skyscrapers
were possible.

(Simon Schaffer)
Technologies emerged,

which not only worked

to insulate human society
against the evils of cold,

but turned cold
into a productive,

manageable,
effective resource.

On the one hand,
the steam engine;

on the other,
the refrigerator--

those 2 great symbols
of 19th-century world,

which completely
changed the society

and economy of the planet.

All that is
part of, I think,

what we could call
bringing cold to market.

Turning it from an evil agent
that you feared

into a force of nature
from which you could profit.

(narrator)
The explosive growth
of the modern world

over the last two centuries

owes much
to the conquest of cold,

but this was only the beginning

of the journey
down the temperature scale.

Going lower
would be even harder,

but would produce
greater wonders

that promise extraordinary
innovations for the future.

With rival scientists racing
toward the final frontier,

the pace quickens
and the molecular dance slows

as they approach the Holy Grail
of cold--"Absolute Zero."

Text : WTC-SWE