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Documentary, The Power of Metals - Greatest Treasures of Earth
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00:00GEMSTONES, PRECIOUS METALS, AND POWER.
00:07THE BUILDING BLOCKS OF CIVILIZATION.
00:12BUT HOW ARE THEY CREATED?
00:15OUR EARTH IS A MASTER SHAFT.
00:17SHE KNOWS HOW TO COOK.
00:20IT'S NOT EASY TO MAKE AN ELEMENT.
00:23YOU NEED TEMPERATURES THAT ARE EXTREME.
00:26IN THIS EPISODE, HOW DO METALS SHAPE OUR WORLD?
00:31I LOVE STEEL.
00:32IT'S ACTUALLY THE BACKBONE OF OUR SOCIETY.
00:36AND WILL THESE GIFTS BE USED TO BUILD THE TOOLS OF TOMORROW?
00:41SO I THINK THE TERMINATOR, HE CAN CHANGE SHAPE AND THEN SELF-HEAL.
00:46ACTUALLY OUR MATERIAL DOES ALL THOSE THINGS.
00:49WE'RE GOING TO LAUNCH THIS INCREDIBLE TELESCOPE,
00:52AND WE'RE GOING TO SEND IT A MILLION MILES INTO SPACE FROM THE EARTH
00:55TO ACTUALLY UNLOCK THE SECRET OF THE UNIVERSE.
00:59AND IT WILL ALL RELY ON TWO OUNCES OF GOLD.
01:04THE POWER OF METALS.
01:08RIGHT NOW ON NOVA.
01:13BY THE LIGHT OF AN ANCIENT CAMPFIRE, A DISCOVERY WAS MADE THAT CHANGED THE COURSE OF HISTORY.
01:22WE DON'T KNOW EXACTLY HOW IT HAPPENED, BUT I SOMETIMES WONDER WHETHER IT WASN'T A COMPLETE ACCIDENT.
01:31WHETHER BY CHANCE OR THROUGH SHEER DETERMINATION,
01:33ONCE HUMAN KIND LEARNED HOW TO HARNESS THE POWER OF FIRE,
01:37WE LEFT THE STONE AGE BEHIND, FORGING OUR WAY INTO THE MODERN WORLD
01:40WITH COPPER, BRONZE, IRON, AND STEEL, THE METALS.
01:47THE METALS.
02:07A WORLD WITHOUT METALS WOULD NOT HAVE TALL BUILDINGS.
02:10IT WOULD NOT HAVE FAST VEHICLES.
02:13Wouldn't be able to have electricity.
02:16Really, our entire modern world is built on the backbone of metals.
02:22Our journey begins with a metal that's transformed life on Earth through its beauty.
02:29A metal that fortune hunters were willing to die for.
02:33And not just in the movies.
02:35There's nothing more beautiful than gold.
02:37Nothing in the world.
02:39You just feel it when you see it.
02:41Ancient people valued gold before the concept of currency or money even existed.
02:48It's something that people intrinsically knew had worth.
02:52Gold is absolutely magical.
02:55Gold is the most fantastic jewelry metal to work with.
03:00It's so soft.
03:01It's so flexible.
03:03It's like butter.
03:05Working with gold ruins you for any other metal.
03:09You're never the same again.
03:10Jeanette, a master jeweler, is making a pair of gold earrings.
03:16I specialize in ancient jewelry making techniques.
03:20The kind of expertise and skill that we're used for making jewelry really made it an art form.
03:28I'd make my own wire and sheet.
03:30And practice techniques like granulation.
03:36The technique I'm going to use for the hanging fringe actually originates from Troy from about 2450 B.C.
03:44Gold is unique among the elements.
03:46Gold is extremely resistant to oxidation, to rusting.
03:51If you make an object out of gold, it's the one thing that you have that doesn't degrade.
03:57So to ancient people, it must have been very, very appealing.
04:00The color of gold draws you in.
04:05Ancient people saw it and knew that it was something incredibly special.
04:10Gold is not only beautiful, it's rare.
04:14In fact, if you take all the gold that's been mined to date,
04:18it's estimated it would fill about a third of the Washington Monument.
04:22But to understand what makes this rare and noble metal last forever,
04:27we need to take a closer look.
04:30A much, much closer look.
04:34Using one of the most powerful electron microscopes in the world,
04:38David Mueller studies the elements.
04:42Probably the most fun in the lab is when you put something in and the picture comes up
04:46and you look and you go, well, that's not what I expected.
04:49That's interesting, and that's usually the start of a new scientific discovery.
04:55Today, Mueller is observing the curious behavior of gold, atom by atom.
05:03All elements are made of atoms.
05:07Inside is a nucleus filled with positively charged protons,
05:11along with neutrons that have no charge at all.
05:15Swirling around the nucleus in a cloud are negatively charged electrons.
05:21It's the relationship between gold's nucleus and its electrons
05:26that holds the key to its resilience.
05:30We're now at 7,000 times magnification,
05:34seven times higher than the highest magnification of an optical microscope.
05:38And if we zoom up some more, you can start to see there's this nice pattern.
05:42These are little islands of gold.
05:44And if we zoom up a little bit further on them,
05:47you'll start to see little bright spots all by themselves.
05:50Those are individual atoms.
05:52Every one of these clusters contains thousands of bright dots,
05:57thousands of gold atoms.
05:59Little gold atoms form small clusters,
06:03and they keep rearranging and changing.
06:06They're not static.
06:07They're not stable.
06:08They're a dynamic.
06:09They're moving all the time.
06:11Gold atoms love to be together.
06:13But when it comes to bonding with other elements,
06:16they're downright antisocial.
06:19When atoms bond,
06:21they do it through their outermost electrons,
06:24by sharing or swapping them.
06:26But gold's 79 protons fight the urge
06:32because they have an immense positive charge.
06:37That positive charge pulls in the electrons.
06:41The real consequence is that the outermost electrons in gold
06:44are much less available for doing chemistry
06:47than we might otherwise expect.
06:51That's why gold doesn't bond with elements like oxygen
06:55that cause metals to tarnish and rust.
06:58The reason that we're able to appreciate
07:00the gold masterpieces from 2400 B.C.
07:04is because gold lasts forever.
07:07It is just as beautiful today
07:08as it was thousands of years ago.
07:11You can't say that about anything else
07:13that you could work in.
07:16How did such a unique metal form?
07:19It's not easy to make an element.
07:25You need temperatures that are extreme,
07:28and we're talking millions of degrees.
07:30The heavier the element,
07:32the hotter the temperature is required to make it.
07:35And you find those temperatures
07:36in the cores of stars
07:38that are 10 times the mass of the sun or greater.
07:41It's within the intense heat and pressure
07:45of these massive cores
07:47that the elements progressively take shape,
07:51bonding together in a process called fusion.
07:55You can sort of imagine building up
07:57all the elements that exist in the universe
07:58by taking a pile of neutrons and protons and electrons
08:03and putting them together
08:04to build up bigger and bigger and bigger atoms.
08:06When the number of protons and electrons hit 26,
08:10forming iron,
08:12the process stops.
08:14Once iron's made in the core, that's it.
08:16There's no more available energy for fusion.
08:19Those massive stars will explode
08:22and go what's called supernova.
08:25One of the key open questions, though,
08:27was what about the heavier elements?
08:28What about gold and platinum and uranium?
08:30Where do those come from?
08:32At the end of supernova explosions,
08:35new kinds of stars are formed,
08:38called neutron stars.
08:40They often come in pairs, binary stars.
08:45They're extremely dense and compact and heavy.
08:48It weighs about 1 1⁄2 times the mass of our sun,
08:52but it's the size of a city,
08:53like New York or London or Boston.
08:56And they incorporate a lot of neutrons,
08:58which is why they're called neutron stars.
09:01Some scientists theorize
09:04that elements heavier than iron
09:06were created in the collision of two neutron stars.
09:11What happens when they collide?
09:16Fusion on a massive scale.
09:19The elements were spread throughout the cosmos,
09:23so they were in the mix
09:25when our solar system formed 4.5 billion years ago.
09:30And later, more were delivered to Earth
09:33by comets and asteroids.
09:38Most of the elements on the periodic table
09:40came to us from space.
09:42We classify them in groups defined by their characteristics.
09:48The largest group is the metals.
09:53And one of the most beautiful by far is gold.
09:58Now, this ancient treasure is going back to space,
10:03on board the most advanced telescope ever built.
10:08It's the next big space telescope.
10:11We like to call it Hubble 2.0.
10:13Hubble 2.0 is the James Webb Space Telescope.
10:18In 2018, we're going to launch this incredible telescope,
10:22the largest space telescope mankind has ever built.
10:24And we're going to send it a million miles into space
10:27to stare at the earliest part of the universe,
10:30and it will all rely on two ounces of gold.
10:35The ultra-thin layers of gold
10:38that coat the telescope's mirrors
10:40give it the power to detect galaxies light-years away.
10:45Hubble has sort of found the edge of the visible universe,
10:48but we know there's a whole universe beyond that
10:50at wavelengths called infrared wavelengths.
10:53And that's where gold comes into the picture.
10:57Infrared light is invisible to our eyes,
11:00but we can detect it as heat.
11:03And that's why this thermal infrared camera will pick it up.
11:07So this is my hand as viewed by the camera,
11:10and it's about 97 degrees Fahrenheit.
11:12Now, let's look at my hand reflected
11:14in this ordinary silver-coated mirror.
11:17It says that my hand is 84 degrees Fahrenheit,
11:20which is a lot less than 97.
11:22And that's because the silver-coated mirror
11:24is not a perfect reflector of infrared light.
11:27But if we try this gold-coated mirror...
11:30Now, when I pass my hand's reflection over the gold,
11:35it says that my hand is 97 degrees Fahrenheit.
11:39And so what this shows is that gold
11:41is an almost perfect reflector of infrared light.
11:45And that's why we coat all of the mirrors
11:47of the James Webb Space Telescope in gold,
11:50so that it has an almost perfect view
11:52of the infrared invisible universe.
11:58Gold is that ancient treasure
12:00that we've lusted over over mankind's history.
12:03And here we are, in the 21st century,
12:06using this to actually unlock the secrets of the universe
12:09and perhaps the origins of where we came from.
12:11What a wonderful historical transformation.
12:16Historically, this glittering treasure of the earth
12:19could be found in riverbeds and streams.
12:23But in order to leave the Stone Age behind,
12:26we needed another metal,
12:28one strong enough to shape into tools.
12:31And we found it in the flames of a fire.
12:38Copper, atomic number 29,
12:4129 electrons, 29 protons, and 35 neutrons,
12:47is embedded in a mineral called malachite.
12:50Malachite has this incredible colour, doesn't it?
12:55It's like a Wizard of Oz, Emerald City green.
12:58Malachite has been really important
13:00throughout the history of our civilisation.
13:02This is probably the first mineral
13:04that humans use to actually extract copper metal.
13:08Just imagine the following.
13:11Someone comes home with a beautiful green rock.
13:15Malachite.
13:16They decide to grind it into a powder
13:19and throw it into a campfire.
13:22A magical process occurs.
13:25Nature puts on a light show
13:27as the edges of the flames turn emerald green.
13:31The flame suddenly becomes greenish.
13:34You get these incredible colours.
13:36You have no idea where they come from,
13:38but it certainly provides entertainment.
13:41And at the same time,
13:42that beautiful green rock slowly turns black.
13:46The beautiful green malachite
13:48has burnt away.
13:50What's left behind is copper,
13:52combined with oxygen from the air,
13:55copper oxide.
13:57If you left it in the fire overnight to burn,
14:00then the transformation would have gone even further.
14:04But in order to free copper from oxygen,
14:07requires another ingredient,
14:10carbon,
14:11which is conveniently provided by charcoal,
14:13the residue of burning wood.
14:16I want to recreate that for you.
14:20Sella drops a disk of copper oxide
14:22into a crucible of charcoal
14:24and heats it up in a modern-day fireplace,
14:27the microwave.
14:28What heat really means is that molecules and atoms begin to move much, much faster.
14:36Now it's possible for the carbon to actually strip away the oxygen,
14:41disappearing off invisibly into the air as carbon dioxide.
14:45But the next morning,
14:48the person who's cleaning up the fireplace,
14:51almost certainly a woman,
14:53would have found tiny little shiny nodules lying amongst the ash.
14:58That would have been metal.
15:00This is a magical transformation
15:03that would suddenly have given you a material
15:06that you could shape,
15:07that you could reuse,
15:08that you could make tools with.
15:10This was power indeed.
15:13This was a birth of a whole new technology.
15:17This was copper.
15:20Once our ancestors discovered how to free metal from stone,
15:24the art of smelting,
15:26they had a material they could shape into bowls.
15:30and tools.
15:32But they also discovered it has another surprising quality.
15:37An ancient Egyptian medical text dating back to 1600 BC
15:41reveals copper was used as a disinfectant to clean wounds.
15:46It was also used to make surgical tools.
15:51As late as the 19th century during a cholera epidemic in Paris,
15:56copper workers seemed to be immune to the disease.
16:00But by the 1940s,
16:01with the development of antibiotics,
16:04people lost interest in copper,
16:06its medicinal powers forgotten.
16:10Until now.
16:12At the University of Southampton,
16:15Bill Keevil has set out to prove
16:16copper can help solve a dangerous problem.
16:20Hospital-borne infections.
16:22If a jumbo jet full of people crashed each day
16:27and everyone died, would you fly?
16:29Probably not.
16:31That's how many people die in America each day
16:33from hospital-acquired infection.
16:36Hospitals are a breeding ground for dangerous superbugs.
16:40Just about any surface you touch is a hot zone.
16:43We know superbugs are perfectly happy to survive for many weeks
16:48on a dry touch surface such as stainless steel or plastics.
16:52So we need something that works 24 hours a day,
16:55seven days a week.
16:57Could copper be an answer?
16:59Here, Keevil puts it to the test.
17:03He takes a piece of copper
17:05and a metal commonly used in hospitals,
17:07stainless steel,
17:09and coats them with the superbug MRSA,
17:12along with a green fluorescent dye.
17:16Next, they place it in a microscope.
17:19Please start your clocks,
17:21and we will follow this experiment
17:22over the next five minutes.
17:25At first, the bacteria on the copper
17:28and stainless steel glows bright green.
17:31But within minutes,
17:32the copper in the screen on the right turns black.
17:36This is what they look like
17:37at the start of the experiment,
17:39and this is after five minutes.
17:41So you can see they're all dead.
17:44How does copper do it?
17:48Scientists suspect it has something to do
17:50with the membrane of a superbug,
17:53which has an electrical charge.
17:56When it meets up with copper,
17:58a kind of short circuit occurs.
18:01The copper penetrates the membrane,
18:03leaving it with gaping, oozing holes.
18:06The copper invades the superbug,
18:09destroying its DNA.
18:12If there's no DNA, there's no growth,
18:14and in fact, there's no chance of mutation,
18:18and therefore, you can't get resistance.
18:20Copper's ability to kill germs
18:22could one day save millions of lives.
18:26But it's already revolutionized the way we live,
18:30because copper has another extraordinary ability.
18:35It conducts the electricity that powers the planet.
18:40Metals are extremely unusual materials.
18:43They can conduct electricity extremely well.
18:46And when we think about conducting electricity,
18:49what that means is that there are electrons
18:52within the material which are able to move.
18:55Sometimes this is described as a sea of electrons.
18:58You can kind of picture these individual atom cores,
19:02and then this sea of electrons all around them.
19:05Metal atoms are arranged in orderly rows and columns.
19:09In between those columns are electrons
19:12that are able to move around.
19:14When we apply a voltage with a battery,
19:17we can start to draw electrons
19:19so that they all move collectively in one direction.
19:23With a voltage applied,
19:25electrons hop from one atom to the next.
19:29That's what gives us the electric currents
19:31that are so useful.
19:33While all metals can conduct electricity,
19:37copper is one of the best,
19:39and it's abundant.
19:42The worldwide supply is about 6 trillion pounds.
19:46But the qualities that make copper the metal of choice
19:49to wire the planet also limit its usefulness.
19:54That sea of electrons not only conducts electricity,
19:57it creates flexible bonds between the atoms.
20:00The atom cores can move through this sea of electrons
20:05in a relatively easy way,
20:07and that's what makes metals malleable.
20:10But a metal like copper,
20:12which is malleable enough to be stretched
20:14into thin, flexible cable,
20:17does not a dagger make.
20:19Copper is actually too soft.
20:22A blade made of copper loses its edge within moments.
20:26And yet, by combining it with other rocks
20:29in the fireplace made of tin,
20:32you could make a material
20:34which was stronger, harder, and stiffer.
20:37That was bronze.
20:39Around 2500 B.C.,
20:42humankind took the art of smelting
20:45one step further
20:46by mixing metals
20:48to create an alloy.
20:51When you look at copper, it's pretty boring.
20:53Every single atom looks the same.
20:54But when you look at bronze,
20:55there are two different types of atoms.
20:57There's copper and there's tin.
20:59Adding tin to copper
21:00changes the properties of the metal.
21:04The larger tin atoms
21:05restrict the movement of the copper atoms.
21:09It makes it more difficult
21:10for the atoms to move past one another
21:13to change shape.
21:14Saying that it's more difficult
21:15to move them around
21:16is equivalent to saying
21:17that the metal is stronger.
21:20Bronze would have provided useful implements
21:22for agriculture,
21:24but more importantly,
21:25it would have provided you with weapons
21:27to establish your dominance.
21:29And dominance, of course, means control.
21:32And control means power.
21:35The movies paint a vivid picture
21:38of how bronze transformed the nature of warfare.
21:42It's the Bronze Age,
21:44so without bronze,
21:45you don't stand a chance in battle.
21:47Bronze is like no other material
21:49people would have handled before.
21:51With it, you can make harder weapons,
21:54you can make sharper blades,
21:57and you can make them consistently.
21:58You can cast them in mold
21:59and make them always of equal quality.
22:02With bronze,
22:03you can, for the first time really,
22:05equip hundreds, thousands of warriors
22:07with the same types of weapons,
22:09all of which will perform
22:11and be equally lethal.
22:13So it probably meant
22:14a revolution in warfare.
22:17But not all swords
22:19are created equal.
22:21Back in 1965,
22:24a group of archaeologists
22:26discovered more than 50 ancient tombs
22:29in the Hubei province of China.
22:31During the excavation,
22:33they unearthed something extraordinary.
22:35Ti Gao Hu was one of the first people
22:39to lay eyes on it.
22:41Hu, an expert in the preservation
22:43of ancient relics,
22:45vividly remembers
22:46seeing a most unusual sword.
22:51The sword had a golden sheen to it
22:54and had a decent weight to it.
22:57It had the shine of fresh copper.
23:00There was no rust at all.
23:02Although it had been buried
23:05for more than 2,400 years,
23:08the sword was perfectly preserved.
23:11Hu found eight characters
23:13written in ancient Chinese script
23:15on the base of the blade.
23:18They identified the sword's owner,
23:21Go Tian,
23:22the king of Yua,
23:23a famous ruler
23:24in the 5th century B.C.
23:26Everyone came to see the sword,
23:32excited because there were characters on it.
23:35One young man was particularly excited
23:38and he tried to reach for it
23:40and he bumped into me.
23:41I leaped forward a little
23:43and I must have touched the sword.
23:46And the sword made a cut
23:47about 2 to 3 centimeters on my hand.
23:51There were droplets of blood
23:54coming from my wound.
23:56It wasn't a deep cut,
23:58but the cut anyhow
23:58were like a shaving razor.
24:02The sword was that sharp.
24:06Later, they tested the sword.
24:09It could cut through 20 sheets of paper.
24:13It was so beautifully crafted.
24:16I was astounded.
24:18The gold jian sword
24:22is well preserved
24:24because of its burial condition.
24:26It is dry
24:27and no water leaked inside.
24:29Thus, it did not rust.
24:32But its longevity
24:33may also be due
24:35to the extraordinary craftsmanship
24:37with which it was made.
24:40The smelting technology
24:42from ancient times has been lost.
24:45But recently,
24:46there were people
24:47who start to imitate the styles.
24:50However,
24:51they can't manage
24:52to replicate its sharpness.
24:54The sophistication
24:56cannot match up to ancient times.
25:00But bronze
25:02has another resounding quality.
25:06It's the perfect metal
25:08to forge a bell.
25:10In South Korea,
25:14master craftsman Song Chang-il
25:16is making a 10-ton bell
25:18for a Buddhist temple.
25:22After decades of experience,
25:24combined with an artist's instincts,
25:27he knows exactly what it takes
25:29to make a bell
25:30with the perfect ring.
25:32First,
25:3310 tons of copper and tin
25:38are heated to 1150 degrees Celsius.
25:44When the time is right,
25:45Chang-il pours his concoction
25:47into a massive clay mold.
25:51The metal is so hot,
25:53it takes two and a half days
25:55for the bronze to cool.
25:57And the bell is tested
26:07for the first time.
26:09That sound that we hear
26:15is really telling us
26:18about the stiffness
26:19and the resilience
26:20of the material.
26:22So when we hear
26:24the ringing sound
26:25of a bell,
26:27the entire material
26:28kind of swings.
26:30It becomes elastic
26:31and can then come back
26:33and go forward
26:34and back
26:35and forward
26:35and back.
26:39Over thousands of years,
26:42through trial and error,
26:44craftsmen like Chang-il
26:46discovered
26:47that the perfect ring
26:48could only be achieved
26:50with the perfect recipe.
26:53A balance
26:54between tin
26:56and copper.
26:58But around 1200 B.C.,
27:00as the use of bronze spread
27:03and with supplies
27:04of tin scarce,
27:06once again,
27:07the flames
27:09of a fire
27:10brought us
27:11a powerful metal.
27:14Iron.
27:16Atomic number 26.
27:1926 electrons,
27:2126 protons,
27:22and 30 neutrons.
27:26Freeing iron from stone
27:28meant taking
27:29the technology
27:30of smelting
27:30one giant step further.
27:33charcoal burns
27:36at about
27:371,000 degrees Celsius.
27:39But to smelt iron,
27:41the flames
27:42need to be
27:43a lot hotter.
27:45The answer?
27:47A technology
27:48that could literally
27:49fan the flames.
27:52A furnace
27:52called a bloomery.
27:55This ancient furnace
27:57was built
27:57with heat-resistant walls
27:59made of earth,
28:00clay,
28:01or stone.
28:03At the base,
28:04pipes allowed air
28:05to enter through
28:06an elaborate system
28:07of bellows.
28:09The air was pumped
28:11manually,
28:12by hand
28:13or by foot.
28:16Anyone who's been camping
28:18and has made
28:19a little campfire
28:20knows that if you lean down
28:22and you blow
28:23into the embers,
28:24what they do
28:25is they glow
28:25much more brightly.
28:27because you're
28:28introducing oxygen
28:29and you're raising
28:31its concentration,
28:32you're making
28:33it more available.
28:35A fire
28:36needs oxygen
28:37to burn
28:38and the more oxygen,
28:40the hotter
28:41the flames.
28:42The reaction
28:43of oxygen
28:44with the charcoal,
28:46which makes
28:46carbon dioxide,
28:47is one which
28:48generates
28:49an increase
28:49in temperature.
28:50You get a release
28:51of heat.
28:54Oxygen
28:54made the fire
28:55hot enough
28:56to separate
28:57iron
28:57from stone.
28:59And once again,
29:01metal transformed
29:03the way we live,
29:05from tools
29:06to weapons.
29:08In time,
29:09the bloomerie
29:09was replaced
29:10with the more powerful
29:11blast furnace.
29:14And by the 20th century,
29:16iron was everywhere.
29:19The Industrial Revolution
29:20changed nearly
29:22every aspect
29:23of life on Earth.
29:26but there was a catch.
29:28In the process
29:29of smelting iron,
29:31impurities
29:31called slag
29:33are left behind.
29:35Slag
29:36weakens metal.
29:39Over hundreds of years,
29:40craftsmen discovered
29:41that if iron
29:42is hammered
29:43and reheated
29:44over and over again,
29:46it gets purer
29:48and stronger.
29:52Over time,
29:53bit by bit,
29:54they discovered
29:55how to get
29:56more and more
29:57of what they wanted
29:58in terms of properties.
29:59But they certainly
30:00didn't have any
30:01understanding
30:02at anything
30:02even remotely
30:03like the atomic level
30:05of what was going on.
30:07But now we understand
30:08that at the atomic level,
30:10an extraordinary
30:11transformation
30:12was taking place.
30:15Iron was turning
30:16into one of the strongest
30:17alloys on Earth.
30:20Steel.
30:22While hammering
30:23drove out the slag,
30:25the charcoal
30:25in the fire
30:26provided an essential
30:27ingredient,
30:29carbon.
30:30The combination
30:31of iron and carbon
30:32to make steel
30:34is almost a unique
30:36combination in the world.
30:38And key to it
30:39is that the iron atom
30:41and the carbon atom
30:42are very different sizes.
30:44When you add
30:45a little bit of carbon
30:46to iron,
30:48it tends to hide
30:49in the little gaps
30:51in between
30:52the large iron atoms.
30:54The way tin
30:54transforms copper
30:56into bronze,
30:58carbon turns iron
31:00into steel.
31:02And this is one
31:03of the amazing things
31:04about steel.
31:04Just using more or less
31:06just these two elements,
31:08iron and carbon,
31:08you can create
31:09lots of different
31:10properties
31:11that can be useful
31:13for different applications.
31:15To demonstrate
31:16the difference
31:17between iron and steel,
31:19Vinci got access
31:20to a piece
31:21of one of the most
31:22famous iron towers
31:24ever built.
31:25This is our piece
31:27of the Eiffel Tower.
31:28Discarded
31:29after a repair.
31:31I never thought
31:31in my life
31:32I would be holding
31:33a piece of the Eiffel Tower.
31:34I mean,
31:34I've been up
31:35the Eiffel Tower
31:35a couple of times.
31:37The Eiffel Tower
31:38is made of wrought iron,
31:40which has less carbon
31:41than steel.
31:42When the Eiffel Tower
31:43was built,
31:44wrought iron construction
31:45was really at its peak.
31:47It's an amazing structure
31:48using an amazing material,
31:50especially for its day.
31:52How does the strength
31:54of the wrought iron
31:55in the Eiffel Tower
31:56hold up against steel?
31:59Rick Vinci
32:00and Helen Chan
32:01are about to find out.
32:03Not only do we get
32:04to hold a piece
32:05of the Eiffel Tower,
32:06but we also get
32:06to cut it up
32:07and bend it
32:08and maybe even break it.
32:09They conduct
32:10a bend test
32:11to determine
32:12how much force
32:13can be applied
32:14to the wrought iron
32:15before it bends.
32:17Here we go.
32:20It not only bends,
32:22it breaks.
32:24Wow.
32:25It broke.
32:27Okay.
32:27This is actually cracked.
32:29When they test the steel,
32:33there are similarities
32:34and differences.
32:37Well, it actually seems
32:39as if the two samples
32:41behave pretty much the same.
32:43The load that it took
32:44to bend it was comparable.
32:47Okay.
32:48So I see two differences
32:49right away.
32:50First of all,
32:51the wrought iron bar cracked
32:52and the modern steel didn't.
32:53But I see another
32:54really important difference,
32:55which is the modern steel bar
32:57is only half the thickness
32:59of the Eiffel Tower bar,
33:01despite the fact
33:02that it carried
33:03exactly the same load.
33:04So what that means
33:05is if you're using
33:06a modern steel
33:07for the same amount
33:08of material,
33:09you can support
33:10four times the load.
33:12Wow.
33:13All right.
33:14In fact,
33:15around the time
33:16the Eiffel Tower was built,
33:18steel was already
33:19on its way
33:20to becoming
33:20the medal of choice
33:22for building high.
33:24Chicago's towering
33:2510-story home insurance building,
33:28the world's first skyscraper,
33:30had a steel frame.
33:32Steel had a huge influence
33:35on the development
33:36of this country
33:37as an industrial nation.
33:39And today,
33:41steel can do things
33:42that are hard to imagine.
33:45Nothing demonstrates
33:46that quite like
33:47the Beijing National Stadium,
33:50nicknamed
33:51the Bird's Nest.
33:5342,000 tons
33:56packed into a design
33:57that seems to defy logic.
34:01Engineer Michael Kwok
34:03was a project manager
34:05for the design
34:06and construction
34:06of the Bird's Nest.
34:08It's more like
34:09a jigsaw puzzle.
34:10You just try to figure out
34:12how this will put together.
34:13And this is exactly
34:14the cleverness
34:15about this building.
34:17It is very unlike
34:19pretty much any other structure
34:21that's been built.
34:22If you want to make
34:23a strong structure,
34:24there are certain
34:25classic shapes
34:26that work very, very well.
34:27And the truss
34:28is a classic one.
34:30If you look at bridges
34:31all over the place,
34:33they have these triangular elements,
34:35these truss elements
34:36that are very, very strong.
34:37The geometry of a triangle
34:40makes it an inherently
34:41stable shape.
34:43Put several of them
34:44in a row
34:44and they distribute
34:45the weight of a structure
34:47to its load-bearing beams.
34:49But Bird's Nest
34:51looks nothing like that.
34:52But looks
34:54can be deceiving.
34:5624 sets of columns
34:58connect to a series
34:59of trusses
35:00that support the roof.
35:02All this
35:03is hidden behind
35:04a maze of steel.
35:07You can't make that
35:08out of just any
35:08run-of-the-mill steel.
35:09You need a particularly
35:11high-strength
35:12and tough steel.
35:14The stadium
35:15is made of
35:16two kinds of steel.
35:17The recipe for the trusses
35:19provides extra strength.
35:21We use special steel
35:22at the location
35:23where it's most stressed,
35:26where it takes up
35:27the highest loading.
35:29If you look at this column,
35:32it is the bending parts
35:34which actually takes up
35:35the heaviest loading.
35:37And this is where
35:38we use the thicker steel.
35:42But to create
35:42the beauty
35:43of its winding exterior
35:45required steel
35:46with more flexibility.
35:48For a massive steel
35:50structure like this,
35:52the combination
35:53of flexibility
35:54and strength
35:55is critical.
35:58Especially in an
36:00earthquake-prone region
36:01like Beijing.
36:03Steel can stretch
36:05and elongate
36:06without breakage.
36:07This is what we need.
36:08We need elements
36:09to be able to
36:10deform without breakage.
36:14When the earth
36:15becomes the roof,
36:16it moves a lot.
36:17But actually,
36:18it's okay.
36:19It moves means
36:20it actually
36:21dissipates energy.
36:23It doesn't actually
36:24affect its stability.
36:26And people
36:27underneath the roof
36:28can actually evacuate.
36:29The bowl of the stadium,
36:32made primarily
36:33of concrete,
36:34does not have
36:35the elasticity
36:35of steel.
36:37So the engineers
36:38and architects
36:38came up with
36:39an innovative idea.
36:41Separate concrete
36:42from steel.
36:44Make them work
36:45as two independent
36:46structures.
36:48So the two
36:49actually are
36:50completely separate.
36:51So when
36:52the earth comes,
36:53the two actually
36:54will respond differently.
36:56The extraordinary
36:58properties inherent
37:00in steel
37:00make it possible
37:02for engineers
37:02like Michael Kwok
37:04to build structures
37:05like this
37:06that capture
37:08the imagination.
37:10People really love
37:11the first nest
37:12because it's not
37:14a simple stadium.
37:16Probably more accurate
37:17way of describing it.
37:18It is sculpture
37:19made by steel.
37:21Today,
37:23by mixing
37:24different types
37:25of steel
37:25for different purposes,
37:27engineers have
37:28taken the art
37:29of steelmaking
37:30to new heights.
37:32Literally.
37:34The tallest
37:35bridge in the world,
37:37the Miou Viaduct
37:38in France,
37:39is made of steel
37:40that contains
37:41an element
37:41that's quite rare,
37:44niobium.
37:46It is a soft,
37:48whitish-gray metal.
37:49And if you add
37:51it to steel,
37:52you get a stronger,
37:54lighter material.
37:56When you think
37:57about a solid
37:58piece of metal,
38:00it just looks
38:00like it's all
38:01the same.
38:02But in fact,
38:02if you really
38:03zoom in,
38:04that chunk
38:04of metal
38:05is typically
38:05made up
38:06of lots
38:06of little
38:07individual
38:07metal grains.
38:08And it turns out
38:09that if you can
38:10make those grains
38:10really tiny,
38:12then it makes
38:13it much more
38:13difficult for the
38:14atoms to move
38:15past one another
38:16to change shape.
38:17So by making
38:18the grains tiny,
38:19you make the metal
38:20stronger.
38:22Niobium prevents
38:23the growth
38:24of these grains
38:26very effectively.
38:27And then you can
38:27get incredible
38:28strength that comes
38:29from having
38:30this very tiny
38:31grain size.
38:33Different kinds
38:34of steel
38:34can have other
38:35additives like
38:36nickel,
38:37chromium,
38:38or manganese.
38:40But there's
38:41one rather
38:42bizarre recipe
38:43that could help
38:44solve one of
38:45the world's
38:46biggest problems.
38:47We've been
38:48seeing landfills
38:49as a huge
38:50environmental
38:50burden.
38:52And of course,
38:53it appears
38:53that way on
38:54surface,
38:55because we
38:55don't know
38:56what else
38:57to do with it.
38:58But if we can
38:58reform end-of-life
38:59materials into
39:00completely different
39:01products,
39:02then suddenly
39:02landfills
39:03shouldn't be
39:04seen as a
39:04burden.
39:05They should
39:05actually be
39:06seen as this
39:07amazing
39:08possibility.
39:10It's a
39:10treasure.
39:11Veena Sajwala
39:12has developed
39:13a way to
39:14recycle the
39:15stuff nobody
39:16wants,
39:17trash,
39:18and turn it
39:20into steel.
39:21The most
39:21basic steel
39:22is nothing but
39:23an alloy of
39:24iron and
39:25carbon.
39:26But guess
39:26what?
39:26We can find
39:27carbon in
39:28plastics.
39:29The first
39:30step,
39:32take some
39:32plastic like
39:33this broken
39:33headlight.
39:36So,
39:36look at what
39:37I got here.
39:38cut off a
39:40piece and
39:40melt it down
39:41to a small
39:42pellet,
39:43chock full
39:44of carbon.
39:45Top it
39:47off with a
39:47lump of
39:48pure iron.
39:51Place the
39:52combo back
39:53in the
39:53furnace and
39:54heat it up.
39:57Now,
39:58watch the
39:59alchemy unfold
40:00as the
40:01carbon in
40:02plastic bonds
40:03with iron.
40:05What's exciting
40:06here is that
40:07we're actually
40:07seeing this
40:08high-temperature
40:08reaction taking
40:09place right in
40:10front of our
40:11very eyes.
40:12We've got this
40:13liquid metal.
40:14We're now
40:15looking at how
40:16this is interacting
40:17with this source
40:18of carbon,
40:19which of course
40:20is the plastic
40:21that came from
40:22a waste out
40:23of a car.
40:24Carbon from
40:25that plastic is
40:26actually able to
40:27dissolve into
40:28liquid metal.
40:29So this is
40:30what's come
40:31out of the
40:31furnace.
40:32We've dissolved
40:32the carbon
40:33from the
40:34plastic into
40:34liquid iron.
40:36And of course
40:36what we have
40:37here is steel.
40:39After a decade
40:40of research,
40:41Vena's green
40:42steel is slowly
40:43making its way
40:44out of the
40:45lab.
40:46Partnering with
40:47the manufacturer
40:48OneSteel,
40:49they have already
40:50recycled over
40:51two million
40:52tires.
40:54Today's tires
40:55are made of
40:55synthetic rubber
40:56produced from
40:58oil rich in
40:59carbon, the
41:01perfect ingredient
41:02for green
41:03steel.
41:05And when it
41:06comes to
41:07greenhouse gases,
41:08Vena's steel
41:09requires less
41:10coal to cook,
41:12and that reduces
41:13its carbon
41:14footprint.
41:15As the saying
41:16goes, you know,
41:17one person's
41:18trash is somebody
41:18else's treasure,
41:20guess what?
41:20This could become
41:21a society's
41:22treasure.
41:24I love steel
41:25because it has
41:26really given us
41:27the structures
41:27that have changed
41:28this world around
41:29us.
41:30Steel has given
41:32us the power
41:32to build high
41:34and strong.
41:36But as wonderful
41:37and versatile as
41:38it is, steel
41:40has limitations.
41:42One of the
41:43drawbacks to
41:44steel is that
41:44it is relatively
41:45heavy.
41:47Iron is fairly
41:47dense, and for
41:49its strength, you
41:50have to make
41:50massive structures.
41:52And that's fine
41:52if you're building
41:53a bridge, but
41:54it's not fine if
41:55you're building
41:56something that
41:56needs to move.
41:58And that's
41:59where another
42:00extraordinary metal
42:01comes into the
42:02picture.
42:04Atomic number
42:0413, aluminum,
42:07has just 13
42:08electrons, 13
42:10protons, and 14
42:11neutrons.
42:13In comparison
42:14with a heavier
42:14metal like iron,
42:16which has twice
42:17the number of
42:17protons, electrons,
42:18and neutrons,
42:20the aluminum atom
42:21is incredibly
42:23light.
42:25Aluminum has an
42:25ethereal lightness
42:27that no one
42:28could believe.
42:29And yet, it also
42:30has some of the
42:31properties like
42:32steel that allow
42:33you to modify
42:34its strength and
42:35its other
42:36characteristics to
42:37optimize it.
42:38Aluminum has
42:39completely transformed
42:40our world.
42:42From the trivial
42:43tent pegs of our
42:44tents to the
42:45frames of our
42:46aircraft, where it
42:48really makes a
42:49difference, if we
42:50had to build our
42:51airplanes out of
42:52steel, they would
42:53have to have fuel
42:54tanks five or six
42:55times bigger than
42:56they do now, and
42:58would carry a third
42:59of the passengers.
43:01Today's aluminum is
43:03really fabulous
43:03stuff.
43:04If you can live
43:05with a little bit
43:05less strength in
43:06exchange for a lot
43:07less weight, then
43:08aluminum is an
43:09excellent choice.
43:11But as we look
43:11to the future,
43:12another way to move
43:13forward is to ask
43:15ourselves if what
43:16we have been doing
43:17with metals for all
43:18of these years is
43:19the only thing we
43:20can do.
43:21Imagine a material
43:22that is not just
43:23light, not just
43:25strong, but flexible
43:27enough to change
43:29its shape.
43:30So I think of the
43:31Terminator with this
43:31project, which is
43:33super fun, and I
43:34don't think I've seen
43:34the Terminator since
43:35I was young, but one
43:36of the images that
43:37really stuck with me
43:38is the T-1000, you
43:40know, the all-metal
43:41guy, right?
43:43He can change shape
43:45and then self-heals.
43:46Actually, our material
43:48does all those
43:48things.
43:50This is metal foam,
43:53a combination of
43:54metal and rubber
43:56heated up and it
43:57morphs into another
43:59shape.
44:00And when it's done,
44:01it becomes a solid
44:03again.
44:04The idea of this
44:05metal foam is that
44:05we can have something
44:07that changes its
44:07shape dramatically,
44:09but then after it
44:10changes its shape,
44:11have a lot of
44:12strength.
44:12What's the recipe
44:14for making metal
44:15foam?
44:17First, take a dash
44:19of Himalayan salt.
44:21Add a little
44:22dragon skin, also
44:25known as uncured
44:26silicon.
44:30Mix it up.
44:33Pour the mixture
44:34into a mold.
44:36And let it cure.
44:37Remove the concoction
44:40from the mold and
44:42place it in an
44:43ultrasonic cleaner.
44:45This dissolves away
44:47the Himalayan salt.
44:50What's left behind
44:51is a porous,
44:53sponge-like material
44:54riddled with tiny
44:56crevices.
44:58Next, submerge the
44:59foam into a bath
45:00of molten
45:01Fields metal.
45:03Fields metal is a
45:05low-melting-temperature
45:06alloy of indium tin
45:07and bismuth.
45:08So, at 60 degrees
45:10Celsius, it is a
45:11molten liquid.
45:12Below 60 degrees
45:13Celsius, it's a
45:14frozen solid.
45:16The metal-covered
45:17foam is sealed
45:18in a vacuum chamber
45:19where the molten
45:20metal seeps into
45:22those tiny crevices
45:23that were left
45:23behind by the salt.
45:26Air trapped in the
45:27foam is pushed out
45:29and rises to the
45:30surface.
45:32The sample is then
45:33removed from the
45:35vacuum chamber,
45:36and cooled down.
45:38Once it's at room
45:39temperature, it
45:40hardens again.
45:42Shepard hopes one
45:43day metal foam
45:45will be able to
45:47make like a bird.
45:49One of the problems
45:49I'm trying to solve
45:50with this material is
45:52inspired by a puffin.
45:54A puffin can fly,
45:56but then it can dive
45:57underwater to catch fish.
45:59So it has to sweep
46:00its wings back in order
46:02to not have its wings
46:03torn off.
46:03So in an artificial
46:05version of the puffin,
46:06we would want a vehicle
46:08that could turn from
46:09a plane to an
46:10underwater glider.
46:11This idea is quite
46:12imaginative and a
46:13far-reaching goal,
46:14but we are currently
46:15working on a wing
46:16that we will coat in
46:18the skin of this
46:19metal foam, and we're
46:20going to try it out on
46:22a radio-controlled
46:22airplane in the next
46:23year.
46:23But metal foam could
46:26find another home, in
46:29space.
46:30You think about kind
46:31of a limited resources
46:32setup, certainly if
46:34you're like in outer
46:34space, and you have a
46:36limited number of things
46:37you can bring with you,
46:37and maybe you don't know
46:38exactly what tools you
46:40need, but here you have
46:41this material, and you
46:44can really change its
46:45shape and then lock it
46:46into whatever you need.
46:47So you can take it one
46:48day and use it as a
46:49wrench and take it the
46:50next day and use it as a
46:52hammer.
46:53One day, metal foam
46:55could make its way
46:56into your toolbox.
46:58Eventually, we believe
46:59this composite could be
47:00used for reconfigurable
47:01tools.
47:02At this point, we think
47:04there are some flaws in
47:05the structure that may
47:07cause it to fracture,
47:08but these are
47:08engineering problems
47:09that we think are
47:10very solvable.
47:12While some researchers
47:13are exploring new ways
47:15to combine materials,
47:18others, like David
47:19Mueller, are fascinated
47:21with a newly discovered
47:23treasure, the strongest
47:25material ever found,
47:27graphene.
47:29Made of pure carbon,
47:31graphene behaves a lot
47:33like a metal, but it's
47:35about 200 times stronger
47:37than steel and harder
47:39than diamonds, even though
47:42it's just one atom thick.
47:46Graphene has incredible
47:48strength.
47:48strength, combined with
47:50incredible strength, it has
47:51incredible flexibility.
47:54How strong is graphene?
47:58Some researchers estimate it
48:00would take an elephant
48:01balanced on a pencil to break
48:03through a sheet of graphene the
48:05thickness of sarana.
48:10Where can it be found?
48:12You have to bake it.
48:17First, take a piece of copper
48:19and place it in an oven.
48:21Fill it with a material that
48:22contains carbon.
48:25David Mueller uses methane, a gas
48:27that's a combination of carbon
48:29and hydrogen.
48:30We knock all the hydrogen off it
48:32by heating it up very hot, so it
48:35gets turned into just carbon
48:36atoms that are floating around
48:38in a vapor.
48:39Those carbon atoms fall down
48:41and bombard a flat surface.
48:44So the way to think of this is
48:46my copper surface is just like a
48:48cold window on a cold day, and
48:51then little bits of moisture are in
48:53the air, and they start to
48:54condense onto my cold window, and
48:56instead of growing little ice
48:58crystals that decorate all the way
48:59across my window, I'm going to
49:01grow little crystals of carbon
49:03that are going to decorate my
49:04copper surface, and eventually
49:07these little crystals are going
49:08to grow bigger and bigger and
49:09bigger until eventually they
49:11touch each other, and then I
49:12have one uniform continuous sheet
49:14of carbon, and that will be the
49:15graphene.
49:17What makes this incredibly thin
49:20layer of carbon so strong?
49:23It all comes down to the
49:25arrangement of its atoms.
49:28When six carbon atoms bond, they
49:31form a hexagon, and as more and
49:34more carbon atoms join the group,
49:36more hexagons take shape.
49:40So you can imagine that if
49:41another carbon atom comes down and
49:43lands over here, right in the
49:45middle, it's got nothing to stick
49:47to.
49:48It's going to keep rolling around,
49:50but then it gets to the edge of the
49:51sheet of the graphene and says,
49:52wait a minute, there's a dangling bond.
49:55I want to attach to that, and then
49:57it'll continue to grow out, and
49:58that's why the sheet gets bigger and
49:59bigger and bigger.
50:02Once the baking is done, the
50:04graphene-coated copper is taken out
50:07of the oven and placed in a solution
50:09that slowly etches the metal away.
50:11What's left is a small sheet of
50:17graphene.
50:19Exactly what can you do with a single
50:21layer of graphene that's so thin it's
50:24barely visible?
50:26So we could imagine graphene would be
50:28very valuable for things on the
50:30nanoscale?
50:31Because it's both tiny and strong, it
50:35could fit inside a cell for medical
50:37applications, or be placed in dust for
50:41environmental monitoring.
50:43But graphene might also have applications
50:46on the mega scale.
50:48If you could build cables, for instance,
50:51for holding up suspension bridges, if you
50:53could get to that size scale, then that
50:56would open up incredible new engineering
50:59opportunities for creative people to make
51:02structures that we really can only
51:03dream of today.
51:06Is graphene the next big thing?
51:10No one can predict if new metals like
51:13metal foam or graphene will live up to
51:17their promise.
51:20But there's no doubt that metals have
51:23revolutionized life on Earth.
51:26From the beauty of gold,
51:28to the smelting of copper, to the
51:32creation of bronze and steel, and in the
51:36future, materials we can only dream of.
51:40And the astonishing thing is that the work
51:43of engineers, of metallurgists, and of
51:45chemists, every year brings us new
51:49formulations, new possibilities, that makes
51:53things lighter, stronger, stiffer, faster
51:57than anything that came before.
Recommended
50:03
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