9:59:59.000,9:59:59.000
What would you say

9:59:59.000,9:59:59.000
is the most important discovery

9:59:59.000,9:59:59.000
made in the past few centuries?

9:59:59.000,9:59:59.000
Is it the computer?

9:59:59.000,9:59:59.000
The car?

9:59:59.000,9:59:59.000
Electricity?

9:59:59.000,9:59:59.000
Or maybe the discovery of the atom?

9:59:59.000,9:59:59.000
I would argue that it is this chemical reaction:

9:59:59.000,9:59:59.000
a nitrogen gas molecule

9:59:59.000,9:59:59.000
plus three hydrogen gas molecules

9:59:59.000,9:59:59.000
gets you two ammonia gas molecules.

9:59:59.000,9:59:59.000
This is the Haber process

9:59:59.000,9:59:59.000
of binding nitrogen molecules in the air

9:59:59.000,9:59:59.000
to hydrogen molecules,

9:59:59.000,9:59:59.000
or turning air into fertilizer.

9:59:59.000,9:59:59.000
Without this reaction,

9:59:59.000,9:59:59.000
farmers would be capable of producing enough food

9:59:59.000,9:59:59.000
for only 4 billion people;

9:59:59.000,9:59:59.000
our current population is just over 7 billion people.

9:59:59.000,9:59:59.000
So, without the Haber process,

9:59:59.000,9:59:59.000
over 3 billion people would be without food.

9:59:59.000,9:59:59.000
You see, nitrogen in the form of nitrate, NO3,

9:59:59.000,9:59:59.000
is an essential nutrient for plants to survive.

9:59:59.000,9:59:59.000
As crops grow, they consume the nitrogen,

9:59:59.000,9:59:59.000
removing it from the soil.

9:59:59.000,9:59:59.000
The nitrogen can be replenished

9:59:59.000,9:59:59.000
through long, natural fertilization processes

9:59:59.000,9:59:59.000
like decaying animals,

9:59:59.000,9:59:59.000
but humans want to grow food

9:59:59.000,9:59:59.000
much faster than that.

9:59:59.000,9:59:59.000
Now, here's the frustrating part:

9:59:59.000,9:59:59.000
78% of the air is composed of nitrogen,

9:59:59.000,9:59:59.000
but crops can't just take nitrogen from the air

9:59:59.000,9:59:59.000
because it contains very strong triple bonds,

9:59:59.000,9:59:59.000
which crops cannot break.

9:59:59.000,9:59:59.000
What Haber did basically

9:59:59.000,9:59:59.000
was figure out a way

9:59:59.000,9:59:59.000
to take this nitrogen in the air

9:59:59.000,9:59:59.000
and put it into the ground.

9:59:59.000,9:59:59.000
In 1908, the German chemist Fritz Haber

9:59:59.000,9:59:59.000
developed a chemical method

9:59:59.000,9:59:59.000
for utilizing the vast supply of nitrogen in the air.

9:59:59.000,9:59:59.000
Haber found a method

9:59:59.000,9:59:59.000
which took the nitrogen from the air

9:59:59.000,9:59:59.000
and bonded it to hydrogen

9:59:59.000,9:59:59.000
to form ammonia.

9:59:59.000,9:59:59.000
Ammonia can then be injected into the soil,

9:59:59.000,9:59:59.000
where it is quickly converted into nitrate.

9:59:59.000,9:59:59.000
But if Haber's process was going to be used

9:59:59.000,9:59:59.000
to feed the world,

9:59:59.000,9:59:59.000
he would need to find a way

9:59:59.000,9:59:59.000
to create a lot of this ammonia quickly and easily.

9:59:59.000,9:59:59.000
In order to understand

9:59:59.000,9:59:59.000
how Haber accomplished this feat,

9:59:59.000,9:59:59.000
we need to know something

9:59:59.000,9:59:59.000
about chemical equilibrium.

9:59:59.000,9:59:59.000
Chemical equilibrium can be achieved

9:59:59.000,9:59:59.000
when you have a reaction in a closed container.

9:59:59.000,9:59:59.000
For example, let's say you put

9:59:59.000,9:59:59.000
hydrogen and nitrogen into a closed container

9:59:59.000,9:59:59.000
and allow them to react.

9:59:59.000,9:59:59.000
In the beginning of the experiment,

9:59:59.000,9:59:59.000
you have a lot of nitrogen and hydrogen,

9:59:59.000,9:59:59.000
so the formation of ammonia proceeds a high speed.

9:59:59.000,9:59:59.000
But as the hydrogen and nitrogen react

9:59:59.000,9:59:59.000
and get used up,

9:59:59.000,9:59:59.000
the reaction slows down

9:59:59.000,9:59:59.000
because there is less hydrogen and nitrogen

9:59:59.000,9:59:59.000
in the container.

9:59:59.000,9:59:59.000
Eventually, the ammonia molecules reach a point

9:59:59.000,9:59:59.000
where they start to decompose

9:59:59.000,9:59:59.000
into the hydrogen and nitrogen.

9:59:59.000,9:59:59.000
After a while, they two reactions,

9:59:59.000,9:59:59.000
creating and breaking down ammonia,

9:59:59.000,9:59:59.000
will reach the same speed.

9:59:59.000,9:59:59.000
When these speeds are equal,

9:59:59.000,9:59:59.000
we say the reaction has reached equilibrium.

9:59:59.000,9:59:59.000
This might sound good, but it's not

9:59:59.000,9:59:59.000
when what you want

9:59:59.000,9:59:59.000
is to just create a ton of ammonia.

9:59:59.000,9:59:59.000
Haber doesn't want the ammonia to break down at all,

9:59:59.000,9:59:59.000
but if you simply leave the reaction

9:59:59.000,9:59:59.000
in a closed container,

9:59:59.000,9:59:59.000
that's what will happen.

9:59:59.000,9:59:59.000
Here's where Henry Le Chatelier,

9:59:59.000,9:59:59.000
a French chemist,

9:59:59.000,9:59:59.000
can help.

9:59:59.000,9:59:59.000
What he found was

9:59:59.000,9:59:59.000
that if you take a system in equilibrium

9:59:59.000,9:59:59.000
and you add something to it,

9:59:59.000,9:59:59.000
like, say, nitrogen,

9:59:59.000,9:59:59.000
the system will work

9:59:59.000,9:59:59.000
to get back to equilibrium again.

9:59:59.000,9:59:59.000
Le Chatelier also found

9:59:59.000,9:59:59.000
that if you increase

9:59:59.000,9:59:59.000
the amount of pressure on a system,

9:59:59.000,9:59:59.000
the system tries to work

9:59:59.000,9:59:59.000
to return the pressure it had.

9:59:59.000,9:59:59.000
It's like being in a crowded room.

9:59:59.000,9:59:59.000
The more molecules there are,

9:59:59.000,9:59:59.000
the more pressure there is.

9:59:59.000,9:59:59.000
If we look back at our equation,

9:59:59.000,9:59:59.000
we see that on the left-hand side,

9:59:59.000,9:59:59.000
there are four molecules on the left

9:59:59.000,9:59:59.000
and just two on the right.

9:59:59.000,9:59:59.000
So, if we want the room to be less crowded,

9:59:59.000,9:59:59.000
and therefore have less pressure,

9:59:59.000,9:59:59.000
the system will start combining

9:59:59.000,9:59:59.000
nitrogen and hydrogen

9:59:59.000,9:59:59.000
to make the more compact ammonia molecules.

9:59:59.000,9:59:59.000
Haber realized that in order to make

9:59:59.000,9:59:59.000
large amounts of ammonia,

9:59:59.000,9:59:59.000
he would have to create a machine

9:59:59.000,9:59:59.000
that would continually add nitrogen and hygrogen

9:59:59.000,9:59:59.000
while also increasing the pressure

9:59:59.000,9:59:59.000
on the equilibrium system,

9:59:59.000,9:59:59.000
which is exactly what he did.

9:59:59.000,9:59:59.000
Today, ammonia is one of the most produced

9:59:59.000,9:59:59.000
chemical compounds in the world.

9:59:59.000,9:59:59.000
Roughly 131 million metric tons are produced a year,

9:59:59.000,9:59:59.000
which is about 290 billion pounds of ammonia.

9:59:59.000,9:59:59.000
That's about the mass

9:59:59.000,9:59:59.000
of 30 million African elephants,

9:59:59.000,9:59:59.000
weighing roughly 10,000 pounds each.

9:59:59.000,9:59:59.000
80% of this ammonia is used in fertilizer production,

9:59:59.000,9:59:59.000
while the rest is used

9:59:59.000,9:59:59.000
in industrial and household cleaners

9:59:59.000,9:59:59.000
and to produce other nitrogen compounds,

9:59:59.000,9:59:59.000
such as nitric acid.

9:59:59.000,9:59:59.000
Recent studies have found

9:59:59.000,9:59:59.000
that half of nitrogen from these fertilizers

9:59:59.000,9:59:59.000
is not assimilated by plants.

9:59:59.000,9:59:59.000
Consequently, the nitrogen is found

9:59:59.000,9:59:59.000
as a volatile chemical compound

9:59:59.000,9:59:59.000
in the Earth's water supply and atmosphere,

9:59:59.000,9:59:59.000
severely damaging our environment.

9:59:59.000,9:59:59.000
Of course, Haber did not foresee this problem

9:59:59.000,9:59:59.000
when he introduced his invention.

9:59:59.000,9:59:59.000
Following his pioneering vision,

9:59:59.000,9:59:59.000
scientists today are looking

9:59:59.000,9:59:59.000
for a new process of the 21st century,

9:59:59.000,9:59:59.000
which will reach the same level of aid