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00:00what's it take to make our modern world I'm David Pogue join me on a high-speed
00:20chase through the elements and beyond as we smash our way into the
00:29materials molecules and reactions it's a really cool enzyme because it makes life
00:34on earth possible that make the places we live the bodies we live in and the
00:40stuff we can't seem to live without the only thing between me and certain death
00:46is chemistry from killer snails it's when you think you've heard of everything
00:52nature will surprise you and exploding glass to the price of pepper-eating pogue
00:58pays gotta be some easier way to learn about molecules in this hour we'll dig
01:06into the surprising ways different elements combined together
01:11and blow apart come for the chemistry but stay for the bacon blowtorch beyond the
01:23elements reactions right now on Nova
01:48imagine that you're about to take your first shot in a game of pool the break but
01:58when the cue ball hits the other balls they all turn into a rat or imagine you snap a pencil in two
02:08and it becomes a flower and a fork that's how weird and surprising some chemical reactions are you can take something as dangerous as the element sodium which explodes on contact with water combine it with a lethal gas
02:28the element chlorine and end up with something utterly different sodium chloride table salt for your fries
02:38transformative chemical reactions are everywhere they're going on all the time
02:46they put the bang in explosives that's a reaction round two and the heat in hot peppers
02:52what am i doing learning how to harness them has given us some control over our world
02:58and maybe even helped to make us human
03:01and few folks know more about chemical reactions this is not normal fire than my old friend
03:12today i've come to his mad scientist lair in illinois to find out more about one of the most powerful weapons in our reaction arsenal
03:24fire fire is a chemical reaction plain and simple it happens to be the most important chemical reaction ever times 10 bar none
03:36when you think about the importance of fire to human beings becoming who we are it's kind of the start of civilization almost discovering how to control this amazing thing
03:47feeds us chases away the bears lights up the night there's almost nothing you could name that's more important than fire
03:54so what is fire anyway
03:58you may have learned this in school
04:01to make fire a kind of combustion you need fuel plus heat plus oxygen
04:08that formula is simple but what's happening isn't
04:13and what's actually happening here it's kind of subtle the wood itself isn't really burning
04:17you see the flames yeah most of the reaction is happening up in the air above the wood
04:23because it needs to mix with air like there's no air in the wood
04:27and what's happening is the heat of the flames here are breaking down and evaporating compounds in the wood
04:32bringing them up into the air
04:34those gases from the wood are complex molecules made mostly of hydrogen carbon and oxygen
04:42when the rising gases enter the high temperature area of the flames
04:47they're joined by oxygen from the air in a swirling cauldron of complicated reactions
04:53the gases break down and their atoms rearrange
04:58if the gases burn completely they'll form water and carbon dioxide
05:03more often incomplete burning produces a variety of other molecules
05:08importantly for us the reactions also release energy
05:13the light you see and the heat you feel
05:16and that at its heart is what happens in chemical reactions
05:22the breaking and making of bonds and the shuffling around of atoms
05:27you take two different things you smash them together
05:31they rearrange themselves and then you get something else comes out
05:35and one of the big time players in the game
05:38is oxygen
05:41and one ready
05:43with enough heat it reacts with just about anything
05:47as Teo soon shows me in his barn
05:50this powerful cutting tool is called a thermic lance
05:55it uses pressurized oxygen fed through a metal rod
06:00this one's made of iron
06:02we don't normally think of iron as something that can burn
06:06but when lit in the flow of oxygen it does
06:10it's generating so much heat
06:12wow
06:13that you can cut through a brick or concrete
06:16demolition crews use large thermic lances
06:21to slice up all sorts of big unwieldy things
06:24from bridges to ships to machinery
06:28but does the rod that burns in the stream of oxygen
06:32need to be metal?
06:36I shudder to ask why you've got plates of bacon here
06:39well because bacon is the funniest thing that you can form into a tube and shoot oxygen through
06:43unfortunately
06:45actual American style bacon
06:47doesn't hold together well enough
06:49we need the engineering grade
06:50this is Italian prosciutto
06:52Teo has already baked some tubes of prosciutto
06:57the next step is to wrap them in yet another piece
07:01to create one large hollow tube
07:04which he hooks up to his oxygen tank
07:06okay so now what can we do with this
07:09the same thing you do with any sort of thermic lance
07:11you cut something with it
07:12uh we're gonna cut steel
07:14because why not
07:16no you're gonna cut steel with bacon
07:18yes a steel baking pan
07:21wow
07:22you just have to get it hot enough
07:23the power of bacon
07:37that's amazing
07:39yeah I mean that's that's a good amount of cutting there
07:43I've heard of steel cut oatmeal for breakfast but
07:46bacon cut steel
07:48gaining control over fire has had an immeasurable impact on human civilization
07:57in fact
07:59the most popular construction material in the world
08:03has its roots in one of the oldest pyrotechnologies
08:06roasting a certain kind of rock
08:11we know it
08:12as concrete
08:18modern concrete is a mixture of aggregate materials like sand gravel and crushed stone
08:25with a binder these days most often cement and that's key because people are always confusing concrete
08:34cement cement is the glue concrete is the end product
08:41cement sidewalks
08:43no that's concrete
08:44cement trucks
08:46uh-uh
08:47they carry concrete
08:49but cement is the key ingredient
08:52and that's why I head to the Lafarge Wholesome Cement Plant
08:56the largest in the U.S.
08:58located outside St. Louis, Missouri
09:00we shoot rock every day
09:03my day with plant manager John Gates
09:08begins with a bang
09:10alright hold on
09:12is it safe to go down there?
09:16not quite
09:16how's that for you?
09:33that's a reaction
09:34that's awesome huh?
09:35do it again!
09:37now that my friends
09:40is a lot of limestone
09:42it's a lot of rock
09:43before long
09:44this will be holding together America's buildings and sidewalks
09:47that's right
09:48we're gonna turn this limestone and to cement
09:51but what exactly is limestone?
09:55it's mostly calcium carbonate
09:59a compound that as its name says has two parts
10:04there's a calcium atom
10:06that has given up two of its electrons
10:08making it a positively charged ion
10:11the other part is carbonate
10:14made up of three oxygen atoms
10:16that are sharing electrons with a carbon atom
10:19sharing electrons is called covalent bonding
10:24the two electrons from the calcium have joined the party
10:27making the carbonate a negative ion
10:31the positive calcium ion
10:33and the negative carbonate ion attract
10:36forming
10:37surprise
10:38an ionic bond
10:43from the quarry
10:44the limestone rock gets gradually crushed down
10:47along with some clay and other ingredients
10:50into a fine powder called raw meal
10:53in preparation to enter the centerpiece
10:56of this whole operation
10:58a rotary kiln
11:00about 22 feet in diameter
11:03and about a hundred yards long
11:05big kiln
11:10largest in the world
11:11kiln as in like an oven?
11:13correct
11:14gas temperatures inside the kiln right here
11:15is about 2,000 degrees Fahrenheit
11:17just before it enters the kiln
11:21the powdery raw meal
11:23is dropped down
11:24through the kiln's hot exhaust gases
11:26by the time it reaches the bottom
11:28and the entrance to the kiln
11:30the heat has transformed the calcium carbonate
11:33from the limestone
11:35into carbon dioxide gas
11:37and calcium oxide
11:39also known as quicklime
11:41normally the kiln rotates at a speed
11:45of about 4 times a minute
11:47inordinarily this whole thing would be turning
11:49but it was shut down for maintenance
11:53oh man
11:54the mouth of the dragon
11:56giving us a chance to see it from the inside
11:59so the whole thing is turning
12:00the whole thing is turning over 4 revolutions a minute
12:03as the material comes down the kiln
12:05there's a burner pipe with a flame right here
12:07inside the kiln
12:09and heating the material at 2,600 degrees
12:11and the flame temperature is about 3,000 degrees Fahrenheit
12:14at this point it looks like dark baby powder
12:17it's at this point it looks like lava
12:19oh it does
12:20yes it's red hot lava
12:24as the main ingredient calcium oxide journeys down the kiln
12:28getting hotter and hotter
12:30it reacts with the other ingredients in the raw meal
12:33creating complex synthetic compounds
12:36by the time the whole mix reaches the end
12:39it has a new name
12:42clinker
12:44this stuff is called clinker?
12:46it's clinker
12:47you couldn't call it something dignified
12:48oh I didn't name it
12:49calcium carbonate or sulfur triacid
12:51clinker?
12:52clinker
12:53coming out of the kiln process
12:54before it goes into the cooler
12:56and clinker just refers to that limestone brew that's been cooked
13:00correct
13:01but it still isn't cement
13:04in the final stage
13:08they add a little more limestone
13:10and hydrated calcium sulfate
13:12a common mineral known as gypsum
13:15conveyor belts seem to really be a thing around here
13:18and the whole thing gets ground back down
13:22to a fine powder
13:24and here it is
13:25at last
13:26no more grinding
13:27no more ingredients
13:28this is the finished product
13:29this is cement
13:30this is cement
13:31from the virgin limestone bluffs of Missouri
13:34there it is
13:35this Lafarge wholesome plant produces up to about 4.4 million tons of cement a year
13:45but that's just a small percentage of the 97 million tons produced in the US
13:51and the 4.5 billion tons produced internationally
13:56virtually all of it ends up in concrete
14:00that mixture of cement water and rock
14:03that is second only to water
14:06as the most consumed resource on the planet
14:12that comes at a price though
14:14a massive carbon footprint
14:18in 2016 cement production emitted about 8% of the global total of greenhouse gases
14:27over half of that from the production of clinker
14:31proposed solutions to this problem range from using wood to build high rises
14:37like this 18 story one in Norway
14:40to injecting CO2 back into concrete as it cures
14:45like this company in New Jersey making pavers
14:49and even growing cement using bacteria
14:54though scaling up those ideas remains a challenge
14:58maybe the solution or part of the solution to greenhouse gas emissions and global warming
15:04will come from a breakthrough in chemistry
15:07that may sound foolishly optimistic
15:10but the discovery of a chemical reaction over a hundred years ago
15:13changed the trajectory of humanity
15:16though few know the story
15:18at the start of the 20th century
15:23farmlands like these didn't look so verdant
15:27and with populations rising
15:29scientists wondered whether in the near future
15:32there would be enough food
15:34the problem was nitrogen
15:41animals need nitrogen to grow
15:43so do plants
15:46but before the 20th century
15:48farmers mainly depended on compost and manure
15:51to supply it to their crops
15:53essentially recycling nitrogen from dead plants and animals
15:57but there was only so much nitrogen in that cycle
16:02eventually the growing population would exceed the farmlands capacity to grow food
16:07leading to mass starvation
16:12but there was a solution in the air
16:14literally
16:16our atmosphere is almost 80% nitrogen
16:20but that doesn't do plants any direct good
16:23that's because it's in the form of N2
16:27two nitrogen atoms sharing in a triple bond
16:31three electrons from each atom are fully shared between them
16:36which as Ed Kussler
16:38a chemical engineer and professor emeritus
16:40at the University of Minnesota explains
16:42makes the nitrogen molecule one tough cookie
16:46so the atmosphere is 78% nitrogen
16:49why can't the plants just take the nitrogen out of the air?
16:52because you can't break this little bastard in half
16:56you take the nitrogen
16:57you have to break this triple bond
16:59between the two nitrogen atoms
17:01and it's almost the hardest bond
17:03the most difficult bond that we know
17:06basically it's almost inert
17:10so the scientific challenge was for someone to find a way
17:13to take that stubborn nitrogen molecule from the air
17:16and bust it apart
17:18to create something plants could use
17:20to invent a synthetic fertilizer
17:23around 1910
17:26German chemist Fritz Haber and his team
17:29found the answer
17:30which they demonstrated using this tabletop machine
17:34from nitrogen gas and hydrogen gas
17:37he could produce NH3
17:40ammonia
17:41a fertilizer itself
17:43and a starting point to produce others
17:46German chemist Karl Bosch
17:50brought Haber's work
17:51to an industrial scale
17:53which is why it's known as the Haber-Bosch process
17:57Ed and his colleague Joe Franek
18:00show me their tabletop version
18:02Joe maybe you can show us a little more hands-on
18:06how the Haber-Bosch process works
18:08all right we're going to put a quantity of nitrogen in this syringe
18:13then we're going to put three times that amount of hydrogen in this syringe
18:17going to light our Bunsen burner
18:19and we're going to pass that mixture of gases over what will be our hot catalyst
18:23which is iron in this case
18:25and that will facilitate the conversion of the nitrogen and hydrogen into ammonia
18:32okay so one syringe full of nitrogen
18:35and three times as much hydrogen
18:37because the formula for ammonia is NH3
18:40there you go
18:41it all makes sense
18:44Joe passes the mixture over some steel wool
18:47heated by a Bunsen burner
18:49the steel wool acts as a catalyst
18:52a material that helps a reaction along while not getting consumed by it
18:58after six minutes it's time to see if it worked
19:02so we now have all of our gases
19:05our unreacted nitrogen and hydrogen
19:07and the ammonia we produce in this one syringe
19:10and what I'm going to do is flush all of these gases through our indicator tube
19:15if we flush some ammonia through these yellow beads they'll turn blue
19:20bravo
19:21I see blue!
19:25so how much ammonia do you think we got?
19:27well our indicator on the tube says that we have just slightly less than two parts per million of ammonia
19:35two parts per million?
19:37so out of every million molecules we got two of ammonia?
19:42at room temperature this process barely works
19:46and even with our burner heating things up a bit
19:49nitrogen gas is so inert
19:52the reaction isn't much better
19:54part of the problem is that this equation is a two-way street
19:59some reactions are one-way, irreversible
20:04when you bake a cake you can't unbake it
20:07but the Haber-Bosch process like many reactions goes both ways at the same time
20:14so while some of the nitrogen and hydrogen are forming ammonia
20:19some of the ammonia is breaking down into nitrogen and hydrogen
20:24the trick is to find the optimal conditions where that balance heads in the direction you want
20:30one tool is pressure
20:35Bosch's industrialized version compressed the gases to around 175 times normal atmospheric pressure
20:43and that huge pressure cooker ran very hot
20:47550 degrees Celsius
20:49around a thousand degrees Fahrenheit
20:52enough to make the hydrogen and nitrogen react with the catalyst
20:56but not so hot as to break up a lot of ammonia
20:59though the process requires extreme conditions
21:04the discovery of a way to split apart that stubborn nitrogen molecule changed the world
21:10it opened the door to the creation of artificial fertilizers
21:17and it's hard to overstate the impact of the Haber-Bosch process on our ability to feed humanity
21:25what were the lasting effects of this introduction
21:29two billion more people
21:31if you lose this chemical fertilizer you lose two billion people they starve
21:36this is not a hypothetical issue
21:39the Haber-Bosch is the chemistry that you wish for
21:43because it's the chemistry that improves the amount of food that you can grow on our planet
21:49and that makes an enormous difference to the stability the health
21:54the well-being of the people on the planet
21:57so one chemical reaction wound up radically changing humanity
22:04yeah some people argue it's the most important single chemical reaction
22:08wow
22:12but before you go out and hug your nearest ammonia producing chemical plants
22:18you may want to consider the downsides
22:21now that fertilizer is abundant growers often apply too much
22:26runoff fertilizer has led to giant algae blooms and dead zones in oceans
22:33also making ammonia uses a lot of fossil fuel
22:38annually the industry as a whole accounts for one percent of global CO2 emissions
22:44Ed Kussler is part of a team of scientists at the University of Minnesota working on a greener approach to producing ammonia
22:58this is the industrial Haber-Bosch process in a smaller package
23:05this ammonia reactor here is making about 25 tons of ammonia a year
23:09standard commercial ammonia plant is making thousands of tons a day
23:12oh so this is a much smaller scale
23:16it still depends on high temperature and pressure
23:18but it's powered by nearby wind turbines
23:22you're taking nitrogen out of the air
23:25you're making hydrogen out of the water
23:28you're making it out of nature
23:29yep right here in this room
23:31the long-term vision is that small facilities like this pilot plant
23:35could make enough green ammonia for a county's worth of farms
23:40in this area about 130,000 acres
23:44we are making fertilizer from air and water
23:47it's just straight alchemy
23:50you're not going to get rich doing it in the new green way
23:53but you can sure make a difference in the way the planet is
23:56scientists estimate that 50% of the nitrogen atoms in any person alive today
24:05at one point passed through the Haber-Bosch process
24:09yet Fritz Haber's legacy is mixed
24:13he won the Nobel Prize in chemistry for his discovery
24:17but is also considered the father of chemical warfare
24:21having proposed and supervised its use in World War I
24:26by the German army
24:28some historians believe that the Haber-Bosch process itself
24:32may have extended that war by years
24:36because it gave Germany a new source of nitrogen compounds
24:40key ingredients in explosives
24:47what makes them key?
24:50it all goes back to that stubborn nitrogen molecule
24:54think of it like a spring
24:56pulling the atoms apart takes a lot of energy
24:59and sticking them into nitrogen compounds
25:02keeps them separated
25:04but in explosives
25:06those compounds are designed to fall apart quickly
25:09freeing the nitrogen atoms to spring back together
25:13and releasing the stored energy from pulling them apart
25:22it seems like a good place to blow stuff up without risking hitting anything
25:26yeah that's why we like having our surrounding mountains
25:29to better understand the role of nitrogen compounds in explosives
25:34I've decided to return to see some old friends
25:37the engineers and scientists at the Energetic Materials Research and Testing Center
25:42at New Mexico Tech
25:45we've had some fun in the past
25:47this is the most fun tailgate you'll ever come to
25:57so let's see what Ordnance Tech
26:00Jonathan Merkel
26:01and Chemist Tom Pleva
26:03have in store for me today
26:05it's cotton?
26:08cotton balls?
26:10that's correct
26:11like cotton balls?
26:12yep
26:13now you might think that cotton balls don't explode
26:17and you'd be right
26:20that was underwhelming
26:22cotton fiber is about 90% cellulose
26:27a key structural component in green plants
26:30composed of carbon, hydrogen and oxygen
26:33but no nitrogen
26:36so our cotton balls will burn
26:39eventually
26:40though not explode
26:42the spores are erupting
26:45but back in the mid-1800s
26:48chemists discovered that they could add to cellulose
26:51what are called nitro groups
26:54each a nitrogen and two oxygen atoms
26:57that turned it into nitrocellulose
27:00also called gun cotton
27:03those nitro groups made something that burns like this
27:07into something that burns like this
27:10flash paper
27:12but nitrocellulose is no joke
27:16in a confined space like a gun barrel
27:19it can be powerful
27:21it was the propellant the military used
27:23to launch the shells
27:25out of these 16-inch guns
27:26on Iowa-class battleships
27:31and it's still a propellant today
27:33in 155-norometer artillery
27:41our next test
27:42okay
27:43is 50 pounds of nitrocellulose propellant
27:47the kind used in those large-bore guns
27:50we give you 50 pounds of gun cotton
27:53since the sphere container isn't sealed
27:56it won't explode
27:58delivered unto the earth
27:59but what will happen
28:01after Jonathan wires it up
28:03we head to a nearby bunker to find out
28:08here we go
28:09three, two, one
28:11compared to plain cotton
28:15this is a show
28:16the burning nitrocellulose
28:18generates rapidly expanding gases
28:21including carbon dioxide
28:23carbon monoxide
28:24water vapor
28:25and of course
28:26nitrogen
28:27it's pretty
28:28packed behind a shell
28:30in the barrel of a gun
28:32the pressure from the expanding gases
28:34would hurl the shell forward
28:36in our open bowl
28:38it's more like fireworks
28:39with the gases
28:40sending burning pellets
28:42up in the air
28:43that's just a propellant
28:44that's a low grade here
28:46we're going to move on
28:47to actual explosives now
28:49oh yeah?
28:50what's first up?
28:51so we're going to start off with ANFO
28:52ANFO
28:53that is the biggest mining explosive
28:54that we have
28:55oh cool
28:56ANFO is an industrial explosive
29:00used in mining and construction
29:02it accounts for about 80%
29:05of all the explosives
29:07used in North America
29:09probably no chemical
29:12shows better
29:13the intimate relationship
29:14between fertilizer
29:15and explosives
29:17though the name ANFO
29:19stands for ammonium nitrate
29:21and fuel oil
29:23it's over 90% ammonium nitrate
29:26the same stuff
29:27as synthetic fertilizer
29:29ammonium nitrate
29:32is built around nitrogen atoms
29:34so it packs way more nitrogen
29:36than nitrocellulose
29:38that means ammonium nitrate
29:41can be very dangerous
29:43this is the aftermath
29:46of the deadliest industrial accident
29:48in US history
29:50the explosion of over 2,000 tons
29:53of ammonium nitrate aboard a ship
29:55in Texas City, Texas in 1947
29:58in 2020
30:01in Beirut, Lebanon
30:03there was a similar explosion
30:05a waterfront warehouse
30:10containing thousands of tons
30:12of ammonium nitrate
30:13caught fire
30:14and detonated
30:16the blast killed over 200 people
30:21injured thousands
30:22and left an estimated 300,000 homeless
30:26our ANFO test will be just 50 pounds of the stuff
30:3550 pounds
30:36to get a reaction going
30:38even one that will release a lot of bang
30:40you need to put some energy into it first
30:43to get some of the bonds to break
30:45that's called activation energy
30:49this is nitrogen triiodide
30:52an explosive whose existence is so precarious
30:56minimal activation energy is needed
30:59even just the touch of a feather
31:02in contrast ANFO is hard to set off
31:09so Jonathan hooks up a booster
31:12a smaller explosive
31:16since much of Emmer Tech's research
31:18and training involves explosions
31:20in human-occupied environments
31:22they typically add a wooden dummy
31:24for scale
31:25and to demonstrate an explosive's effect
31:28you good?
31:29you good?
31:30you good
31:31okay, here we go
31:32three, two, one
31:37that my friend is a firecracker
31:40that was like seven stories
31:43so what just happened?
31:45Jonathan ignites the booster
31:49that's the black smoke you see
31:54the pressure wave from the exploding booster
31:57in turn detonates the ANFO
31:59breaking the bonds holding the ANFO atoms together
32:03they rearrange into more stable gases
32:06nitrogen, carbon dioxide, and water vapor
32:09along with some carbon monoxide and nitrogen oxides
32:12the hot gases rapidly expand
32:16creating a supersonic shock wave
32:19traveling at about two miles per second
32:22if you look at just the nitrogen atoms of the ANFO
32:25it's like the un-hover process
32:28most of the nitrogens from the ammonium ions
32:31and nitrate ions
32:32reunite into their more stable preferred state
32:36N2
32:37in fact, about half of the power of the ANFO explosion
32:44comes from nitrogen atoms reforming into nitrogen molecules
32:51here we are, what, a quarter of a mile away?
32:54and you could feel the ground shaking
32:56yep
32:57and that's 50 pounds
32:58that's only 50 pounds, yes
32:59next up, you've seen it in movies
33:05and you probably even know its name
33:08what's that?
33:09it's C4
33:10and just one look at its active ingredient
33:17should tell you we've upped our game
33:19cyclotrimethylene trinitramine
33:22commonly known as RDX
33:25while it has three nitro groups
33:28there's even more nitrogen built into its ring
33:31and even though the nitrogen triple bond
33:34is one of the strongest in nature
33:36the single bonds between the nitrogen in the ring
33:40and the nitro groups are rather weak
33:43often the first to fail when detonated
33:45oh my
33:49last one for the day for us
33:54uh, yeah, 50 pounds of C4
33:56alright
33:58should I be offended that
34:01they've dressed him like me?
34:03is there a hidden message in that?
34:05I wouldn't take it personal but
34:07you know
34:08alright
34:15oh, wait, I gotta go do that
34:17oh, but it looks so cool
34:19I know
34:20I
34:21charging
34:22okay, here we go
34:24three
34:25two
34:26one
34:27oh my god
34:32when the detonation pressure wave
34:38hits the RDX molecule
34:40the ring compresses
34:42and then flies apart
34:44the atoms recombine into carbon monoxide
34:47water vapor
34:48and nitrogen gas
34:50those reactions produce far more heat than ANFO does
34:53which makes the gases expand much more rapidly
34:56giving RDX over twice the explosive power
35:02so we have more heat and energy in there
35:05there's more nitrogen in there
35:07exactly
35:11does that mean that the future is just all nitrogen?
35:14that is the goal
35:15we are trying to make entirely nitrogen composed explosive molecules
35:21here's one from the drawing boards with a great name
35:23octa-azacubane
35:25entirely made of nitrogen
35:27it is predicted to have a faster velocity of detonation
35:30than any known non-nuclear explosive
35:33if someone can just figure out how to make it
35:36I think that's all that's left
35:42and so ends our day of the un-haber-bosch process
35:47much of the nitrogen in our explosives
35:51has returned to its happy
35:53or at least extremely inert state
35:56as N2 molecules in the atmosphere over New Mexico.
36:04In chemistry, reactions tend to consume other ingredients,
36:08transforming them into something new.
36:11That's the process that chemical equations are designed to explain.
36:15But in biology, molecules can sometimes bind to each other
36:19without consuming or producing anything new.
36:22They can act as triggers or messengers.
36:25Or, as it's sometimes described, like a key fitting into a lock.
36:35To learn more about molecular locks and keys,
36:38I've come to experience them viscerally.
36:44Here at the Berks Pepper Jam in Bethel, Pennsylvania.
36:47Smell that!
36:49An annual festival of food, entertainment, and contests.
36:54All centered on chili peppers.
36:57Reaper Evil Hot Sauce.
36:59They do have an ambulance on hand, right?
37:01They do.
37:02When it comes to peppers, I'm a novice.
37:05But the first thing you need to know is that the black pepper you see sitting with salt
37:10and chili peppers have different chemistries and histories.
37:17Black pepper is the dried, ground-up fruit of a flowering vine native to Asia.
37:22Its kick comes mainly from the molecule piperine.
37:28While one side of the world had black pepper, the other side had chili peppers.
37:33First domesticated by Mesoamericans and then traded around the world by European explorers.
37:39The main active ingredient in chili peppers is the molecule capsaicin.
37:47More on that in a bit.
37:49Three, two, one, eat!
37:53The jam features a pepper eating contest.
37:56For kids.
37:57But they wouldn't let me in.
38:00So I plan on entering the one for adults.
38:03After I get some advice.
38:05I've actually never eaten a pepper by itself.
38:08Bow out when you feel you should.
38:10Really?
38:11Raw pepper is a completely different deal.
38:14I can't do it.
38:15You can't eat a reaper?
38:16Is there any way I can prepare?
38:18I guess your will made out.
38:20You don't have anything to do for the next three days, do you?
38:22Yeah, you're gonna feel great Monday morning.
38:26A big round of applause for Lizzie.
38:28Well done!
38:31Time to put my tongue to the test.
38:33Long hot.
38:34Red Fresno.
38:35Here's how the contest works.
38:37There are 10 rounds of increasingly hot peppers.
38:40Peach Copahagin.
38:43Big red mama.
38:44Their spiciness, measured on a scale, invented in 1912 by pharmacist Wilbur Scoville.
38:52It estimates the amount of capsaicin in each pepper.
38:56Contestants have to eat a pepper
38:58and then wait two and a half minutes to allow the burn to grow.
39:04If they drink the milk in front of them, a popular way to douse a tongue on fire.
39:09They are eliminated.
39:11They're out.
39:12My competitors include some rugged-looking characters.
39:16And Leah.
39:17I've never done this before.
39:18I figured this out two hours ago.
39:21A 15-year-old who entered with the permission of her parents.
39:26We begin our contest with the long hots.
39:31Let's turn up the heat!
39:32Eat!
39:33Eat!
39:34And we're off.
39:36Zesty.
39:37With just a hint of poison.
39:39Round two, we're gonna start with the red Fresno pepper.
39:42Eat!
39:43Eat!
39:44Eat!
39:45Eat!
39:46Eat!
39:47Eat!
39:48Gotta be some easier way to learn about molecules.
39:50All right, are we ready?
39:51Eat!
39:53That was not designed for human consumption.
39:56Round number four, habanero peppers.
39:58The parts of my body I didn't know I had are on fire.
40:03Ten more seconds.
40:04You got this.
40:05I can't.
40:06No, no, no, no!
40:07No!
40:10The orange Copenhagen pepper.
40:15What am I doing?
40:18Oh, man.
40:19Oh, my God.
40:22I want it!
40:23Wherever you are, Scoville, I hope you rot.
40:29Cheers!
40:30No!
40:31No!
40:33So, I'm the first to fall.
40:37Is there a porta-potty?
40:38But there's a bigger mystery.
40:40How does a pepper's capsaicin convince my mouth it's on fire?
40:45Not recommended.
40:48I think I'll find the answer here, at Penn State University's Department of Food Science.
40:53We all study food, so you have psychologists and microbiologists and...
40:58I'm here to see John Hayes.
41:00He knows a thing or two about the active ingredients in these.
41:05So, when you went and tasted them, what did you experience?
41:09Oh, man.
41:11My gut twisted.
41:12My tongue burned.
41:13My flesh burned.
41:14I cried.
41:15I got red.
41:16My nose ran.
41:17It's like putting your tongue on the stove and leaving it there.
41:20That was an aversive response.
41:23This plant has evolved a chemical called capsaicin.
41:27And the reason it makes that is to keep animals from eating the chili.
41:32Oh, man.
41:33The chili festival people never got that message.
41:36And we're just a really stupid species.
41:38Exactly.
41:39We're one of the only species that learns to like that sensation.
41:42Ultimately, pepper plants are playing a pretty good trick on humans as well.
41:49Capsaicin really is a key ingredient.
41:53It has a long spindly tail attached to a ring.
41:57That ring end fits into a specific receptor that's expressed all over your body.
42:03And that's just our tongue.
42:04Not just your tongue.
42:05Oh, man.
42:06And this receptor, this lock, is actually a heat pain sensor.
42:11Normally, the receptor, called TRPV1, activates when it comes in contact with something over 106 degrees.
42:21The result is a pain message to the brain.
42:24Ouch!
42:25Something's hot!
42:27It's a warning signal to tell your body danger.
42:31And here's the tricky part.
42:32When you eat peppers, those capsaicin keys fit into the heat pain receptors in your mouth, altering their sensitivity.
42:42And so what the capsaicin does is it fits into this molecular thermometer and it lowers the temperature at which it activates it.
42:49Like a changed thermostat, they now activate at body temperature, sending a false signal that's identical to the one your brain would receive if you ate something literally burning hot.
43:02It lowers the temperature at which we feel burning pain.
43:07Yes.
43:09But it's not actually burning us?
43:10Correct.
43:11I'm not going to see scar tissue.
43:12No.
43:13No matter how hot it is.
43:14It's all a fake out?
43:15Absolutely.
43:17Up next, the yellow seven-pot pepper.
43:21Back in Bethel, the pepper-eating contest is entering its final rounds.
43:27That one's warm.
43:31Oh, let's burn it now.
43:33I'm trying to think of a happy place.
43:35I can't find one.
43:37Evidence that capsaicin's working on the molecular locks of everyone's heat pain sensors is easy to see.
43:43As they eat a big red mama rated at over a million Scoville heat units.
43:52Don't tap out now.
43:54Don't tap out.
43:56One more falls.
43:59We're down to the final four.
44:02I'm ready to leave. I can't abuse these people anymore.
44:04This time, the organizer adds concentrated pepper extracts.
44:15How long can this go on?
44:20Then, suddenly, a resolution that no one saw coming.
44:25Oh!
44:28Leah beat him!
44:32They round of applause!
44:34They round of applause!
44:36Leah, I am not worthy.
44:38You rock!
44:40What does a woman with that kind of fortitude and strength want to be when she grows up?
44:44A fighter pilot.
44:46Why am I not surprised?
44:48Ultimately, the capsaicin molecule is an illusionist.
44:54Able to trick my nervous system into thinking my mouth is on fire.
44:59But what about the molecules that pose real danger?
45:04Molecules designed by nature to kill.
45:08Time to meet my first professor of venoms.
45:13Mandy Holford of Hunter College.
45:19Now, I couldn't help noticing there's a huge terrifying tarantula on me.
45:24Is she poisonous?
45:26No, no, she's not poisonous.
45:28Oh, phew.
45:29She is, however, venomous.
45:31And could still be lethal.
45:33Thanks for bringing that up.
45:34Poisonous and venomous don't mean the same thing?
45:38No, no, no. Not at all.
45:40Poisonous versus venomous.
45:43It all comes down to the delivery system.
45:46If you bite it and get sick, it's poisonous.
45:50But if it bites you and you get sick, it's venomous.
45:55In general, the source of their toxins is different as well.
45:59This poison dart frog becomes poisonous from its diet.
46:02If raised in captivity on different foods, it can become non-toxic.
46:08Whereas this rattlesnake generates its own venom.
46:13It's built into its DNA.
46:16So snakes, scorpions, spiders.
46:21Which fearsome creature is the focus of Mandy's work?
46:24Killer...
46:28Snails?
46:30Is it accurate to say that you study killer snails?
46:35Killer snails are actually my affectionate term for venomous marine snails.
46:41And so these are snails that live in the sea and they have a venom like snakes or scorpions or spiders.
46:48And the venom can be very lethal to humans.
46:52It's true that the snail can kill you.
46:55But usually it's just looking for dinner.
46:58A worm or a fish.
47:00So I'm a fish. What happens to me?
47:02Well, what happens is this guy will smell that you're in the water, right?
47:06He puts out something called a siphon.
47:09And it's a chemo-sensory organ.
47:11Smells that, hmm, tasty meal in the water.
47:14Then it sticks out something like a tongue.
47:16It's called a false tongue, proboscis.
47:19And on the tip of the tongue it has a little tooth filled with venom that then will get injected into the fish.
47:26Fish instantly will become paralyzed depending on what cocktail of venom gets injected to it.
47:31The snail will then open its mouth really wide, swallow the fish whole, and have a really nice tasty meal.
47:40The whole thing sounds so improbable.
47:43I love it.
47:45Just when you think you've heard of everything, nature will surprise you with something new.
47:49So what's in that paralyzing venom?
47:52To find out, Mandy and her team collect specimens from around the world.
47:56Back at the lab, they analyzed tissue samples from the snail's muscular foot and its venom gland.
48:06So we're eventually going to look at the DNA so we can make a species identification and that we can use the foot tissue for.
48:15And then the venom gland tissue we can use to look for the individual venom toxins within the venom duct.
48:21Turns out the cone snail's venom isn't one thing, but a cocktail of as many as 250 short mini proteins, also called peptides.
48:34So if you think of venom, think of it not as like a single bullet, right?
48:41It's more like, I like to describe it as a cluster bomb.
48:45It's a series of bullets coming at you and each individual bullet has a target in the physiological system.
48:51Each venom peptide has evolved to mount a very specific attack, often acting as keys that fit a cell's lock-like receptors.
49:02In the case of the nervous system, that can prevent a specific neuron from transmitting an impulse.
49:09Or, conversely, jam the neuron open, generating a flood of signals.
49:18In the wild, all those targeted attacks paralyze the snail's prey.
49:23But the precision with which the venom peptides act also means that they may have another role, as medicines.
49:30And so we study these venoms to try to figure out novel medicines for treating things in pain and cancer.
49:39Actually, they make great drugs because they're highly specific, very fast-acting, and very potent.
49:45A venom curing instead of killing wouldn't be the first time.
49:50There are currently at least seven drugs on the market developed out of the study of venoms.
49:58They include an anticoagulant derived from medicinal leeches, and a diabetes medicine from Gila Monsters.
50:07There's even one already from cone snails, an analgesic to treat severe chronic pain.
50:13And it's the exact peptide that you would find in the venom.
50:18It's not a derivative of it. It's not a small molecule.
50:21It's exactly as nature expressed it in the animal.
50:25And I'll just run a simple DNA extraction.
50:28Mandy's team has already made some major breakthroughs.
50:32I could do nano LC-MS and see what's inside of here.
50:35In 2014, they identified a peptide from another venomous snail that attacks liver tumor cells.
50:43Inhibiting their growth.
50:45It's cutting-edge work that's reaping the rewards to be found at the intersection of chemistry and biology.
50:54Learning how the venom is used more in ecological settings helps to further us in terms of how we understand how it can be applied for medicinal or therapeutic applications.
51:06And so right now, it's a fun time to be a venom scientist because those worlds are colliding.
51:10In both chemistry and biology, change is a story told through reactions.
51:18And understanding those reactions has given us new insights into both our world and ourselves.
51:26If you lose this chemical reaction, two billion people starve. This is not a hypothetical issue.
51:32And with that comes a lesson.
51:37Oh, man!
51:39Just as a molecule can act as both a venom and a medicine,
51:43or one reaction can both help feed the world and blow it to bits,
51:49our scientific knowledge is a powerful tool.
51:54The power of bacon!
51:58But it's up to us to learn how to use it well,
52:02as we continue to go beyond the elements.
52:05beyond the elements.
52:35To order this program on DVD, visit Shop PBS or call 1-800-PLAY-PBS.
52:56Episodes of NOVA are available with Passport.
52:59NOVA is also available on Amazon Prime Video.
53:05No, no.
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