Original subtitles

- [Narrator] It's an invisible force all around us.

In the air, and beneath the sea.

It can cut through metal and tear a house down.

- It has a lot to do with weather.

And particularly it has a lot to do with wind.

- [Narrator] From a nuclear explosion.

To blowing up a balloon.

You'll never feel pressure the same way again.

This is Modern Marvels, super power pressure.

[dramatic music]

Pressure is hard at work all around us.

An invisible force that makes

things move faster, change consistency.

Or raise and lower temperature.

Pressure is often hard to see, but it can be measured.

Whether it's in liquids, in solids, or in gases.

Pressure is registered in pounds per square inch or PSI.

That's literally the weight

of one pound pressing down on one square inch.

Add weight, and the pressure goes up.

The water that comes from your tap, that's about 35 PSI.

The water shooting out of a fire hose, about 100 PSI.

[dramatic music] [radio chatter]

[fire engine siren]

Nobody understands the power of PSI like firefighters.

Engine 22 of the Danbury Connecticut fire department

is a state-of-the art mobile firefighting platform

designed to do one thing.

Generate flame killing water pressure, lots of it.

Engines like these are technological marvels.

Capable of delivering more than 1200 gallons per minute,

via multiple hose connections.

That's because the engine's internal pump

creates enormous pressure

that can push water out at top speeds.

Engine 22 only carries 500 gallons.

So these high pressure hoses are going

to need more water, fast.

In most fires, that water comes from a fire hydrant.

A five inch diameter supply hose

locks into the town's water system.

The pressure is on and the hose springs to attention.

But the municipal fire hydrants are unpredictable,

delivering water at varying pressures.

So the fire engine itself juggles the

inflows and outflows, keeping the pressure constant.

Tackling a fire from a ladder truck

adds another layer of complexity.

The engine has to generate additional PSI

to compensate for its height over the ground.

- Attention driver 24 waters on the way.

- [Narrator] It's like pumping a thousand

gallons of high pressure water up a steep hill every minute.

- You have big fire, you need big water.

- [Narrator] Firefighters can't handle

this volume of water by hand.

- We could unsheath all the shingles off this roof.

You're putting a thousand gallons of

water out at 80 pounds

per square inch, that's a lot of force.

It's an awesome amount of power.

- [Narrator] Nothing is more critical

to this high pressure offense than a strong defense.

And it comes from a fire hose.

A flexible cylinder lined with synthetic rubber.

- This is a rubber extrusion machine.

We're making a tube liner.

So the rubber actually works really well

in the fire hose

because it enables the fire hose to dilate

and swell and stretch under pressure.

It also obviously provides sealant

for the water to transfer.

- [Narrator] All American Hose in Western Pennsylvania

uses about two and a half tons

of synthetic rubber every day.

This liner will fit inside a sturdy outside covering

made of tightly woven nylon.

The weaving machines spins at a hundred rpms.

The weave is so tight,

the machine's output is only two feet per minute.

After weaving each jacket is manually inspected for any

defects that could cause the hose to weaken

and burst under firefighting pressures,

The jacket and rubber liner come together

on this 100 foot long table.

- A fire hose is usually made of three sections.

One is the inner rubber liner,

which we insert into the inner jacket.

And then we take that inner jacket liner assembly,

and we insert into an outer jacket

That protects the hose whenever it's under pressure.

It also protects it when it's under fire condition.

- [Narrator] Pressure seals the deal,

with an 80 PSI hot steam treatment for 15 minutes.

The steam expands the hose

to operating size for the first time.

And activates an adhesive

that binds the inner layers together.

The steam heat and pressure

make the fire hose even more rugged.

With the addition of alloy couplings,

the fire hose is almost finished.

But first it must endure a proof test

where it's subjected to 800 PSI.

That's two times greater than the maximum

that firefighters will ever need.

Why?

Because pressure can spike unexpectedly

when hoses are twisted, crimped, or run over.

Some hoses undergo an additional burst test.

Over 1200 PSI.

That's enough to break them open,

but the way this hose is designed to burst

along its seam, it could handle even that.

- Pumped up the hose to the first pressure.

And when the hose burst, we wanted to burst long wise

so it's safe like a banana.

If it bursts in the cross section,

then it can be a loose cannon.

Could have hose flying all around.

- [Narrator] It takes more than 1200 PSI to burst this hose.

A key test of its ability to withstand enormous pressure.

But even to those of us not battling fires,

water pressure plays an essential role.

When you turn on the tap and water flows out,

it's thanks to water pressure.

But how does water pressure work and why is it so reliable?

As a liquid, all water naturally flows downhill,

picking up power and pressure as it travels.

It's the same basic way water gets to your house.

A water tower is simply a large water reservoir

elevated to generate pressure

and propel water into your kitchen sink.

- Water towers use the most patient force I know,

and that's gravity.

All you have to do is rely on the mass of water to push it

through the pipes

and for the most part, you're in pretty good shape.

- [Narrator] Your typical water tower

holds more than a million gallons,

but it's height is its most important feature,

for every two feet that water is raised off the ground.

It contributes one more pound of pressure

or PSI to the system.

A water tower must be tall enough to push water

through a network of pipes

and into surrounding homes and businesses.

Most cities aim to generate pressure between 50 and 100 PSI.

Water towers are usually taken out of service for

maintenance once a year.

This gives us a rare opportunity

to step inside its pressure creating construction.

This tank is over 90 feet in diameter

and it can hold a million and a half gallons.

- When the tank is full,

there would be 35 feet of water above us.

- [Narrator] In Louden County, Virginia,

Coldwell tanks constructed

the country's biggest water tower site.

These two massive 3 million gallon towers

are half steel plate and half reinforced concrete.

- The pedestal has a diameter of 64 feet

and 12 inch thick walls all the way around.

The pedestal height is on the order of 110 feet,

including the dome that is on top of the pedestal.

- [Narrator] The 500 ton tank is hoisted up

to the pedestals dome and locked into position.

This 116 foot diameter tank delivers 50 pounds of pressure

into the local water system.

Serving 15,000 households.

But what happens to your water pressure

if you live in a building

that's taller than the highest water tower?

That's a problem that New York city first faced

more than a hundred years ago when it began to grow taller.

There wasn't nearly enough

water pressure for the top most floors.

the solution became an icon.

A water tank for every building over 80 feet.

- Water tanks are old school, but they still work.

- [Narrator] Water tanks like these

are replaced every 25 years.

The job has to be completed in less than a day.

A challenge American Pipe and Tank is ready to take on.

- While this tank is empty,

this building has no fire protection.

So it's pretty critical

that gets back online as soon as possible.

- The team spends the first two hours

dismantling the old water tank.

- Watch it!

Next, they assemble a barrel

large enough to supply this nine story building.

5,000 gallons should do it.

First, the team erects a circle of stays.

And then tightens them into position by a series of hoops.

All of this while dangling more

than a hundred feet over the pavement.

In New York City,

the majority of old and new water tanks are made of wood.

- Wood is a great material for an outdoor water tank.

Wood is a natural product, it breathes.

It does very well outdoors.

When you actually look at this tank from the top,

you will look down and you will see a true circle,

perfectly milled, and installed like a big jigsaw puzzle.

- [Narrator] Like all water towers,

once completed the tank will require

very little attention to do its pressure generating job.

- The water tank is a very maintenance free type system.

A small pump in the basement fills the tank

and gravity just does the rest.

- [Narrator] While New Yorkers are proud

of their rooftop water tanks,

some landmarks prefer to keep them outta sight.

The Empire State building's one of the first

skyscrapers to hide its water on top.

So even if you don't see them,

water towers and rooftop tanks are up there.

Providing constant water and steady pressure.

But what happens when pressure goes out of control?

Countless aspects of our everyday lives

are under pressure.

We harness water pressure and store

it high in the air until we need it.

We bottle up air pressure and hold it in aerosol cans.

It may be everywhere.

But pressure is not always under our control

[explosions booming]

Explosions.

[explosions booming]

[dramatic music]

An explosion causes rapid expansion,

which gives birth to an unpredictable pressure wave

that can travel over long distances.

But what's really going on here?

Imagine a pebble dropping into a pond.

The ripples move out at a steady pace.

An explosion is something like this,

but in the open air and not at all steady.

Shock waves from an explosion

can only move as fast as the speed of sound.

So they bunch up and that's

what creates a wallop packing pressure wave.

But pressurized gases aren't always destructive.

On a much smaller scale, we even bottle airs

explosive pressure and enjoy it, bubble by bubble.

Avery's beverages has been putting the pop

in soda pop for more than a century.

- If you wanna see what 300 pounds of pressure is like,

I can open a valve here.

It's pretty loud though, I'll warn you ahead of time.

- [Narrator] Rob Metz is the mastermind

who keeps these decades old machines running.

- We're an old fashioned soda company and it's,

as you can see handmade.

And we still make our soda the way it was done years ago.

- [Narrator] That means first making

a batch of flavored syrup

and then adding the other half of the recipe, the fizz.

The bubbles in a soft drink are carbon dioxide or CO2.

That's why we call the process

of putting the bubbles in carbonation.

Pressure plays a role in every step.

Avery stores their CO2 in a liquid state,

under three hundred pounds of pressure

at 40 degrees below zero.

- This is where we control the amount

of pressure going into the carbonator.

And this is where we adjust it

for the different flavors for fruity flavor,

we're gonna have it running around

60 pounds per square inch,

for a higher carbonated mixer or a Cola, a ginger ale,

or we're about 80 pounds per square inch.

- [Narrator] Higher pressure means more bubbles.

And you heard right,

colas contain more bubbles than fruit flavored sodas.

That's simply because we like our colas

much fizzier than other carbonated beverages.

So how does CO2 find its way into water?

- Coming in the, in the top here is our water line

and in the side here is where our carbon dioxide comes.

- Normally you can't see the moment when the fizz goes in.

Here inside the carbonator

pressurized carbon dioxide is forced into the water.

And a unique reaction occurs between the water and the gas.

- Carbon dioxide is special

because it dissolves in the water.

You can get a lot more CO2 into a bottle like this one

than you can nitrogen or oxygen.

And that's because the CO2 is more soluble.

- [Narrator] By the time it's done,

this water will have absorbed three

times its own volume in carbon dioxide.

That's a lot of gas.

And the higher the pressure, the faster

the gas dissolves into the water.

The soda finally comes together at the bottling station.

Where the flavored syrup gets dispensed

and mixed with the carbonated water under pressure.

Then the capper seals it off and traps the CO2.

- When they get down here,

the syrup and the carbonated water aren't mixed.

So every bottle's gonna be

inverted three times one, two, three,

and then they're mixed to stay mixed.

So that's what's happening over here.

- [Narrator] Now it's time to sit back and enjoy.

Just don't shake things up.

Soda pop is by no means the only beverage

in which we find CO2 bubbles.

A celebratory champagne pop?

Tthat's the result of CO2 escaping the bottle,

Shake the champagne and you excite the gas,

creating a surge of bubbles and pressure.

Even agitated, much of the CO2 remains.

There's still plenty of fizz to be enjoyed.

But what if nearly every single CO2 bubble

in a bottle is forced out all at once?

We don't know if history records the first person

who ever tried this, but whoever it is,

they ought to get the Nobel prize for fun.

It's what you're seeing here.

The ultimate example of homemade explosive pressure.

It's now the infamous Coke Mentos experiment.

A roll of candy is dropped into a bottle of Cola

and the pressure release is downright explosive.

How does it work?

Most scientists believe that the unusual surface

of the candy spurs a rapid chain reaction

of bubble formation in which each new bubble

creates even more bubbles

and an instant release of all the pressure

until the bottle is outta gas.

So the explosive froth is all the carbon dioxide

leaving the bottle at once.

[upbeat music]

Like an explosion, there's lots of pressure,

but it's released at a much slower rate.

No pressure wave, no damage.

Just one big mess.

Pressure kicks off many of our days.

It's the driving force behind another foamy mess.

Only when this one blows up, you put it on your face.

When Barbasol was invented in 1919,

it was the world's first shaving cream.

But it didn't become the fluffy stuff

we know today until the 1950s.

With the advent of the pressurized aerosol can.

Before shaving cream, men had to lather up with soap.

Shaving methods have evolved since then,

but the materials, not so much.

A visit to a Barbasol plant in Ohio

reveals that shaving cream still share

a key ingredient with soap, steric acid.

It starts as flakes,

but it slowly transforms into a liquid

as it heats to 150 degrees.

Emulsifiers, sudsing agents, and filtered water

are combined with steric acid

in massive 3000 gallon mixing tanks.

The pressure is yet to come.

Over 10,000 empty cans enter the production line every hour.

A 12 head filler processes 180 of them a minute.

- Well the shaving cream at this stage

pretty much looks like, I would compare it to skim milk.

Fairly watery and cloudy.

It's not until the propellant goes into can

that it gets the foamy rich texture.

- [Narrator] Once valves are crimped to the top of each can,

they're ready to receive pressure.

But for that step,

the entire production line makes a detour

out of the factory building.

The pressure is injected in a gas house.

That's separate from the factory.

Barbasol uses two gases

as propellants, propane and isobutane.

Both are potentially explosive,

which is why this process is done outside the factory walls.

- So if there were a spark present,

the roof would actually get blown off the building

and this room would get foamed to suppress the fire.

- [Narrator] The amount of propellant in a single can

is not enough for a consumer to worry about.

- Once the cans leave this building,

they are under pressure.

- [Narrator] The cans return to the factory under 80 PSI.

Then they run through a hot bath

to ensure that there are no leaks.

The heat increases pressure

to over a hundred PSI, simulating conditions

the cans might encounter during shipping,

But how does shaving cream go

from the consistency of skim milk to this?

You have to understand what's going on inside the can.

The propellant gas is mixed with a soapy solution.

Under pressure, they become a single liquid.

When the valve opens the pressure pushes

the liquid out and foamy cream emerges.

- The material, the propellant,

is above its boiling point at room temperature.

As a result, when I open the valve,

I release the pressure and the propellant boils.

That small amount of liquid turns into a huge amount of gas.

And that's the way you're able to get a large amount of foam

into a small can of shaving cream.

- [Narrator] So inside a can of shaving cream

pressure reveals what a versatile force it can be.

But what if you need a little more power

than the pressure found in a can?

Once you start looking for it,

pressure is just about everywhere.

From the common to the critical.

Plays a role in nearly every job.

Cut something and it's pressure that does the work.

It doesn't matter what's in your hand

or what you're dividing.

[saw buzzing]

The best cutter in the world employs blistering pressure.

Yet it's cutting with nothing more than water.

It's a great demonstration

of the incredible power of liquids under pressure.

But where does all that force come from?

Jet Edge Water Jet Systems has built a machine

that puts water under massive pressure.

It's called, appropriately enough,

a water intensifier system.

A hydraulic pump turns at a hundred horsepower,

generating 3000 PSI.

This pressure is transferred to a cylinder

that uses a piston to put 75,000 pounds

of pressure on water.

If 75,000 pounds of pressure per square inch

sounds like a lot, it is.

Consider this, nuclear subs can't survive

deeper than 2,400 feet in the ocean

where the pressure is a little more than a thousand PSI.

[upbeat music]

Water exits the nozzle at mach two,

roughly 2000 miles an hour.

That's faster than a bullet exits a gun.

A jet of pressurized water has

a lot in common with another high tech tool.

- The ability to concentrate

this stream of water into a into a very small area.

It's kind of like using water as a laser

because that's what a laser beam also does as well.

- [Narrator] The precision of

a water cutter is unparalleled.

The water jet blasts through a sheet of carbon fiber

as if it were butter.

And it will do the same to 12 inch steel or titanium.

- First of all, the water acts as a lubricant.

And second, it also acts as a cooling agent

to take some of that, that heat away.

- [Narrator] Unlike a water jet,

other cutting devices generate heat,

Which can warp the material or make it brittle.

A water jet is unstoppable.

In fact, if it weren't for a two

foot deep bath of water underneath

the material being cut,

the water jet would be carving holes in the factory floor.

- Water can cut a number of things.

You can cut sheet metal, foam, rubber,

but if you want to cut something really thick,

like say six inches of titanium,

then you've gotta add garnet abrasive.

And that is this stuff right here.

- [Narrator] The abrasive adds erosive power

to the pressurized water and accelerates the cutting.

Water jet cutting has been a boon to industries

like auto racing.

Michael Waltrip Racing fields multiple teams

on the NASCAR circuit.

They build dozens of cars in

their North Carolina facility every year.

Custom parts cut by high pressure water

are used every step of the way.

Removing the engine reveals all the parts

cut by the water jet.

- Here we have the bare chassis.

We can see a large number of components

that we cut from the water jet

from our engine Mount here and,

and on the back of the engine.

Suspension pickup parts are all cut from a water jet.

We've got steering arm braces

where the steering connects is all cut on the water jet.

- [Narrator] The water jet cutter shapes

the parts quickly into an engineer's

precise specifications.

When you're traveling at over 200 miles per hour,

where failure can be a matter of life and death.

You wanna know that every part works perfectly.

By machining parts flawlessly,

a water jet cutter makes racing safer.

Pressurized water is ideal for cutting

[water spraying]

and pressurized air can be just as useful.

Although it lacks the weight of water

air pressure can turn into something

that will blow you away.

With a sandblast.

These machines clean the toughest surfaces,

all powered by compressed air.

Nothing beats a sandblaster its scouring paint

or grit and grime from old parts.

And just like with a water jet,

the secret ingredient is another gritty abrasive

that's driven by pressure.

- With pressurized media,

you don't have to go anything over that.

I normally recommend 90 to a hundred for blasting.

When it gets fully decompressed, that handle will drop.

And that tells you you're ready to fill.

Now you're ready to fill.

- [Narrator] If a 100 PSI sand blaster

sounds lame compared to the pressures

of a 75,000 PSI water jet cutter, it's not.

At 100 PSI, a sand blaster

will strip naked skin to the bone.

Bad boy, blasters manufactures custom sand blasters,

and every single one relies on pressurized air.

But blasting with abrasives is a dirty dusty job

and can require a lot of cleanup.

They've invented a vacuum that sucks away the abrasives

and paint as fast as it can be blasted.

The paint dust stays in the air filter.

- Turn on the vacuum.

You see at the one 20 PSI, this was running a 40-60 grit.

How nice of a, that's a good, paintable surface.

- [Narrator] A self-contained blast cabinet

made of welded sheet metal

makes sandblasting even less messy.

Sand blasters are highly efficient,

yet despite the name they don't use sand.

Sand can cause silicosis, a potentially fatal lung disease.

Most industrial sand blasters like these

now use aluminum oxide.

The same material commonly found on sandpaper.

Aluminum oxide can survive multiple runs through a blaster.

- You can blast anything.

I got people doing anything from blasting glass,

doing designs, metal parts, a lot of aircraft industry work.

- It may not pack the punch of a water jet,

but a blast of air pressure is all it takes

to turn an old hunk of metal into something shiny and new.

Pressure is everywhere.

Just look up

The atmosphere rises more than 20 miles over our heads

and all that air has weight.

A very precise weight in fact, 14.7 pounds.

That's how much is pressing down on those of us

who live at sea level all day and we hardly notice.

But there's something that does get our attention.

Atmospheric pressure lows and highs.

We know it as weather.

- Air pressure has a lot to do with weather

and particularly it has a lot to do with wind.

- [Narrator] Check out any weather map.

The highs and lows are air systems

seeking to equalize pressure.

Wind blows from areas of high pressure

into those with low pressure.

- If you want to think of it that way,

the more steep is the drop off from high pressure

to low pressure, the more severe is the weather.

- [Narrator] Up there, it's a maelstrom

of varying pressures, temperatures and humidities.

And in extreme cases, it turns deadly.

But air doesn't exert nearly as much pressure

as the other substance that rings our planet, water.

30 feet of seawater creates the same amount of

pressure as 20 miles of air.

Some of the most destructive forces humans

must overcome are in the deep sea.

At just 100 feet, water pressure

crushes an empty water bottle.

That's how much the air inside it has compressed.

Of course you wouldn't be seeing images like these at all

if it weren't for divers with video cameras.

- We're under a lot of pressure, time pressure,

water pressure, to do a good job.

- [Narrator] Highly trained underwater cameramen

like Bob Cranston put their bodies on the line

every time they dive.

And the video gear they take down with them

is worth tens of thousands of dollars.

For divers, crushing pressures are the enemy.

- And what we're feeling when we go in the water

is the weight of the water over our head.

The deeper we go, the more pressure there is.

- [Narrator] Waterproofing alone won't do it.

The only way you can take a camera underwater

is using a pressure resistant shell

called an underwater housing.

Gates's underwater product designs

housing for all types of cameras.

The process involves a series of trade offs.

The shell needs to be big enough to fit the camera

yet cylindrical in shape to resist pressure.

The fewer, the parts, the fewer things that can go wrong.

The main section of the housing emerges

from a 65 and a half pound block of solid aluminum.

Machines remove 88% of the metal.

Leaving a hollow eight pound cylinder.

Then it's onto the tumbler,

which polishes away any sharp edges

with synthetic rocks and water.

But even if all parts are perfectly machined,

a seal can always fail due to human error.

- The user has to do a,

a visual inspection to make sure there is nothing

on the O ring that can compromise it.

Something as small as say,

a human hair laying across the O-ring

can allow water to pass at that point.

- Large silicone O-ring seal big openings against pressure

and tiny sleeves called glands,

employ a double set of seals

to maintain pressure on the knobs and shafts

that control the camera.

As the last step before plunging into the crushing ocean,

workers test the housing's ability to survive.

First, they test for normal pressure

by sucking all the air out of the housing.

[machine whirring]

- Now we wait to see if there's any changes

in the numbers on the pressure gauge.

- [Narrator] If normal air pressure can't find

its way into the vacuum in the housing,

then it's ready for a much more serious pressure test.

- The housing didn't lose any pressure,

it's perfectly sealed.

- [Narrator] But how will it do

when the pressure is multiplied?

- So now I'm adding pressure to the tank,

which will bring us up to at least a hundred PFI

and simulate our dive to about 225 feet.

[upbeat music]

- Thorough leak testing requires

putting every moving part to the test.

- And looking for any water

that might be in any control shaft

or around any sealing area.

And we'll actually torque on some of the controls

to make sure that we have nothing

in and around the control glands themselves,

checking around the cord area.

This one passed the test.

[water splash]

- [Narrator] Down here, minimal visibility

makes gathering images even more challenging.

Gates camera housings can perform

in waters as deep as 450 feet.

Where the pressure is more than 215 PSI.

About 15 times greater than it is on the surface.

Even at a hundred feet, the PSI is four times greater

than at the surface.

A crushing force that also challenges a diver's body.

- The ocean applies pressure on all air spaces.

Our lungs have air inside of it, our mask, our ears,

all of these areas have to be equalized in our body.

Otherwise we feel squeeze and pain and it's a bad thing.

- [Narrator] Even the air coursing

through a diver's bloodstream changes with the pressure.

This is one of diving's greatest hazards.

Every minute, a diver spends under water

his blood absorbs more foreign gases like nitrogen.

If he ascends to the surface too quickly,

dissolved nitrogen bubbles will turn back into gas.

Just like CO2 in a bottle of soda pop when it's uncapped.

This potentially lethal phenomenon is called the bends.

Divers can use a computer to calculate the amount of

pressure they're exposed to

and calibrate a slow return to the surface.

Coming back from a deep dive

may take hours of slow decompression.

So every diver knows that pressure

is a force to be reckoned with.

Pressure is everywhere.

It's there when we need it.

But when it's outta control, it can be brutally destructive.

It can be our worst enemy under water,

but then we turn around and use it

as the most powerful tool in a factory.

Pressurized cans throughout your home.

They not only deliver foamy lather,

they can also dispense some tasty treats.

Whipped cream isn't the only food

that's created with the help of pressure.

A kernel of corn pops when

the water within it turns to steam.

Water expands 1600 times when it becomes steam.

In an enclosed space,

that creates an incredible amount of pressure.

The industrial revolution changed our world,

but it can only happen after we'd harnessed steam pressure.

So what happens if we bottle up that steam

and put it to work in our kitchens?

This place has almost as much in common

with a science lab as a kitchen.

In fact, they call it the cooking lab.

The team here researched and photographed

a multi volume book called modernist cuisine

to reveal the science behind cooking

and to discover new techniques.

- We use high end technology to play with our food

for the purpose of making it more delicious.

More interesting.

- [Narrator] Pressure is one of any kitchen's

most versatile tools.

Many homes have pressure cookers,

but most of us take them for granted,

rarely stopping to think about how they work.

When you cook in an open pot liquids can never get

any hotter than 212 degrees Fahrenheit.

The boiling point of water.

- The pressure cooker is a fascinating piece of equipment

because it allows us to cook in a high pressure environment.

We increase the pressure to 15 PSI, one bar,

and that's an extremely pressurized environment.

- [Narrator] The pressure is now twice as great as normal,

it's equivalent to being 30 feet under water.

And what's strange is that the water isn't boiling,

it will only do that when

the temperature surpasses 250 degrees,

38 degrees higher than the boiling

point at normal pressure.

That extra heat can brown meats

or caramelize vegetables faster.

- Increasing pressure can speed up cooking,

create new flavors

and really facilitate the cooking process in general.

- [Narrator] Pressure cookers have been around

for more than a hundred years,

but they haven't always had safety features.

Today, the lid is held in place by heavy flanges,

a rubber gasket forms a hermetic seal.

And if the pot over pressurizes,

a safety valve vents the excess pressure.

- It will never explode.

It will just release all that steam and it will be safe.

And now, it's very upset.

- [Narrator] Steam pressure not only cooks,

it can also be put to work sealing food

for long term storage.

- So this is a pressure canner.

Some of the features are a little bit

different than a traditional pressure cooker.

- [Narrator] A pressure canner

is basically a pressure cooker on steroids.

It can withstand almost twice

as many PSI as a pressure cooker.

Rather than a rubber gasket,

it has a metal to metal seal that requires heavy clamps to

bolt it down and hold it in place.

The pressure canner also works double time.

It sterilizes jars while sealing them.

The process of heating and cooling

the jars leaves them with a perfect vacuum seal.

These pressure canned tomatoes

can survive for centuries on the shelf.

Another pressure cooking technique

was perfected to send food into space with astronauts.

It's the opposite of cooking under pressure.

This is cooking in a vacuum.

Flavor, texture and freshness are all preserved.

As water is drawn out under less

than a thousandth of a pound of PSI.

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This is what's called freeze drying.

- These carrots are very light.

Only one to 4% of the water that was

already in them is still there.

It's so it's, it's very, very, very dry.

- [Narrator] Once reconstituted,

these freeze dried veggies look like

something you'd find in a cup of dry noodle soup or ramen.

- So we're freeze drying,

we're manipulating pressure to investigate

the future of cooking.

- [Narrator] Lightweight dehydrated foods are perfect

for outer space.

Where every ounce of launch cargo is carefully managed.

In fact, one dish freeze dried ice cream,

was invented for NASA

and flew on an Apollo space mission in the 1960s.

And it's all thanks to the incredibly

versatile force we call pressure.

We use it to build

and destroy.

To rescue,

to restore,

and to explore.

Wherever you go, and whatever you do,

pressure will be right there with you.

[upbeat music]