female narrator: A TYPICAL PERSON
CONTAINS 15 GALLONS OF WATER,
OVER A PINT OF HYDROCHLORIC ACID,
ENOUGH CARBON FOR A THOUSAND PENCILS,
ENOUGH PHOSPHORUS FOR 3,000 MATCH HEADS.
OUR BODIES SUCK IN OXYGEN,
WHICH COMBINES WITH FOOD IN CHEMICAL REACTIONS,
RELEASING ENERGY TO DRIVE US FORWARD.
BUT THE CHEMICAL WORLD ONLY BEGINS WITH OUR BODIES.
EVERYTHING IN THE WORLD, LIVING AND NONLIVING,
SOLID, LIQUID, OR GAS,
IS MATTER.
MATTER IS MADE OF TINY PARTICLES CALLED ATOMS,
WHICH ARE INVISIBLE
UNDER ALL BUT THE MOST POWERFUL MICROSCOPES.
CHEMISTRY CONSIDERS HOW THESE ATOMS JOIN TOGETHER.
SOMETIMES SUBSTANCES ARE MIXED TOGETHER.
WHEN OIL AND WATER MEET, THEY REMAIN SEPARATE.
NEITHER IS CHANGED BY BEING TOGETHER.
WHEN SUBSTANCES JOIN TOGETHER IN A COMPOUND,
THEY ARE BONDED TOGETHER IN A CHEMICAL REACTION.
A NEW SUBSTANCE WITH DIFFERENT QUALITIES IS CREATED,
ONE THAT CAN'T EASILY BE CHANGED
BACK INTO ITS ORIGINAL INGREDIENTS.
- NOW GET SOME FAIRY DUST IN YOUR HAND AND THROW IT IN HERE.
narrator: IMAGINE TRYING TO GET YOUR FLOUR AND SUGAR BACK
ONCE YOU'VE BAKED IT INTO BREAD.
WHEN WE COOK,
THESE REACTIONS TAKE IN MORE ENERGY
THAN THEY RELEASE,
BUT OTHER REACTIONS RELEASE LOTS OF ENERGY.
ENERGY IN A CHEMICAL REACTION CAN TAKE MANY FORMS,
FROM HEAT TO LIGHT
TO MOTION.
REACTIONS CAN HAPPEN
IN THE BLINK OF AN EYE
OR INVISIBLY SLOW, OVER YEARS.
DIFFERENT SUBSTANCES HAVE DIFFERENT QUALITIES.
THESE UNIQUE PROPERTIES OF MATTER
MAKE ALL THE DIFFERENCE.
THE STORY OF HUMANS
IS LARGELY THE STORY OF OUR INCREASING ABILITY
TO TAKE ADVANTAGE OF THE MATERIALS AROUND US.
EARLY MAN COULD ONLY SHAPE STONE AND BONE.
THE IRON AGE FOLLOWED,
THEN THE INDUSTRIAL REVOLUTION.
AT EACH STAGE, WE DISCOVERED MORE ELEMENTS,
LEARNED MORE ABOUT THE CHEMICAL AND PHYSICAL PROPERTIES
OF THE WORLD.
TODAY WE RELY ON THE STRENGTH
OF THE STEEL IN OUR BUILDINGS AND BRIDGES,
THE POWER STORED IN THE OIL BENEATH THE GROUND,
A MYRIAD OF MEDICINES AND HOUSEHOLD PRODUCTS,
MAN-MADE ALLOYS
THAT WITHSTAND ENORMOUS TEMPERATURES AND STRESSES.
MEANWHILE SILICON SUPPORTS THE NEXT REVOLUTION,
THE INFORMATION AGE.
UNDERNEATH LIES CHEMISTRY.
WHEN A CRIMINAL USES HIS KNOWLEDGE OF SCIENCE
TO COMMIT A CRIME,
THE COPS MUST BE THAT MUCH MORE SCIENTIFIC TO OUTFOX HIM.
IN ONE CASE,
A BRILLIANT FORGER NEARLY REWROTE HISTORY
AND GOT AWAY WITH MURDER,
BUT TWO INVESTIGATORS,
ARMED WITH MICROSCOPES AND A TOY CHEMISTRY SET,
CRACKED THE CASE.
SALT LAKE CITY, 1985.
AT 8:00 A.M., A BOMB
KILLS FINANCIAL CONSULTANT STEVE CHRISTENSEN.
HOURS LATER, ANOTHER BOMB
KILLS THE WIFE OF HIS BUSINESS PARTNER.
THE NEXT DAY, HISTORIC DOCUMENT DEALER MARK HOFMANN
IS BADLY WOUNDED BY A THIRD BOMB.
INVESTIGATORS QUICKLY BEGIN TO SUSPECT
THIS THIRD VICTIM, HOFMANN.
IT TURNS OUT THAT MONTHS EARLIER,
HOFMANN SOLD A CONTROVERSIAL HISTORIC DOCUMENT
TO CHRISTENSEN FOR $40,000.
THE DOCUMENT HAD BEEN AUTHENTICATED BY SEVERAL LABS
AND WAS BELIEVED BY STATE ATTORNEY GEORGE THROCKMORTON
TO BE GENUINE,
BUT THEN HE NOTICED SOME INCONSISTENCIES
AND CALLED IN BILL FLYNN OF THE ARIZONA CRIME LAB.
OVER THE NEXT FEW WEEKS,
THE TWO EXAMINED HUNDREDS OF DOCUMENTS,
SOME OF WHICH HAD GONE THROUGH HOFMANN'S HANDS.
HOFMANN'S DOCUMENTS HAD INK THAT APPEARED CRACKED,
WHILE THE OTHER DOCUMENTS HAD SMOOTH INK.
AND UNDER U.V. LIGHT,
THE INVESTIGATORS SAW FAINT TRAILS OFF THE WRITING.
SOMETHING WAS UP, BUT THEY HAD NO PROOF.
WHEN HOFMANN WAS ARRESTED,
POLICE CONFISCATED A COLLECTION OF BOOKS ABOUT FORGERY.
ONE OF THESE CONTAINED
AN INTERESTING 18TH-CENTURY RECIPE FOR INK,
BUT SINCE NO ONE AT THE LAB
COULD RECOGNIZE THE OLD CHEMICAL NAMES,
NAMES LIKE GREEN VITRIOL,
THE INVESTIGATORS WERE STYMIED.
THROCKMORTON DECIDED TO TAKE A BREAK FROM THE CASE.
THEN ONE DAY,
HE WAS CHRISTMAS SHOPPING IN A TOY STORE
WHEN HE NOTICED A CHILD'S CHEMISTRY SET
WHICH USED THE SAME OLD CHEMICAL NAMES FROM THE BOOKS.
THROCKMORTON WENT HOME AND MIXED UP SOME INK,
BUT HIS INK WAS BLUE,
WHILE HOFMANN'S INK WAS REDDISH-ORANGE.
IRON IN THE INK REACTS WITH OXYGEN OVER TIME,
TURNING TO THE ORANGE WE SEE AS RUST.
COULD HOFMANN HAVE SPED UP THIS AGING PROCESS?
THE BOOKS TOLD HOW THAT COULD BE DONE.
THE INVESTIGATORS SPRAYED THEIR INK WITH HOUSEHOLD AMMONIA,
AND IT TURNED FROM BLUE TO ORANGE
BEFORE THEIR VERY EYES.
IT TURNS OUT THAT AMMONIA SPEEDS UP THE OXIDATION
1,000 TIMES.
IF HOFMANN HAD SPRAYED THE LETTER WITH AMMONIA,
THAT WOULD EXPLAIN THE TRAILING,
BUT UNTIL THEY ACCOUNTED FOR THE CRACKING,
THEY HAD NO CASE--
UNTIL THEY TRIED A RECIPE FOR ONE MORE INK,
WITH GUM ARABIC ADDED FOR GLOSS.
- [sighs]
OKAY, GEORGE, LET'S SEE WHAT WE HAVE HERE.
narrator: THE GUM WAS THOROUGHLY CRACKED.
- SAME AS HOFMANN'S? - THAT'S IT.
TAKE A LOOK AT THE CRACKING.
narrator: THEY HAD FINALLY REPRODUCED
ALL OF HOFMANN'S TECHNIQUES.
UNDER THE MOUNTING PILE OF EVIDENCE,
HOFMANN CONFESSED TO THE FORGERY AND MURDERS,
BUT WHAT HAD CAUSED THE CRACKING?
IT TURNS OUT THAT THE OLD INKS ARE VERY ACIDIC.
WHEN HOFMANN SPRAYED THE INK WITH AMMONIA--
A STRONG BASE, OR ALKALINE--
THE RAPID CHANGE IN pH
CAUSED THE GUM ARABIC MOLECULES TO CLUMP TOGETHER,
CRACKING THE INK.
HOFMANN WILL PROBABLY SPEND HIS LIFE BEHIND BARS,
THANKS TO THE CHEMICAL DETECTIVE WORK
OF THROCKMORTON AND FLYNN.
OVER THE LAST CENTURY,
WE'VE GONE FROM THE HORSE AND BUGGY
TO A WORLD TEEMING WITH HUNDREDS OF MILLIONS OF AUTOMOBILES.
FROM THE MODEL "T" TO THE LATEST RACE CARS,
ONE THING REMAINS THE SAME:
THE INTERNAL COMBUSTION ENGINE.
IN THESE ENGINES, A FINE MIST OF GASOLINE
IS SPRAYED INTO THE PISTON CHAMBER.
WHEN A SPARK IS ADDED,
THE MIXTURE OF AIR AND FUEL EXPLODES,
DRIVING THE PISTON DOWN AND SPINNING THE CRANKSHAFT.
AS THE PISTON MOVES BACK UP,
IT PUSHES THE REMNANTS OF THE EXPLOSION OUT OF THE PISTON
AND THE CYCLE REPEATS.
TAKE THE UNBURNED FUEL
AND CARBON MONOXIDE IN THAT EXHAUST,
MULTIPLY IT BY THE NUMBER OF CARS ON THE ROADS,
AND YOU CAN SEE WHY THE AUTOMOBILE
IS CONSIDERED SUCH A SERIOUS THREAT TO THE ENVIRONMENT.
WHAT IF WE COULD POWER OUR CARS
WITH A DIFFERENT SORT OF REACTION,
ONE THAT RUNS CHEAPER AND CLEANER THAN ANY ENGINE YET?
SCIENTISTS ARE GETTING CLOSER TO JUST SUCH A SOLUTION.
THIS BUS CAN RUN AT HIGHWAY SPEEDS
OVER 100 MILES AT A TIME,
BUT UNLIKE DIESEL-POWERED BUSES,
IT RUNS WITH NO NOISE
AND PRODUCES ONLY WATER AS ITS EXHAUST.
IT'S POWERED BY SOMETHING CALLED A FUEL CELL.
A FUEL CELL PRODUCES ELECTRICITY,
BUT IT ISN'T A BATTERY.
INSTEAD HYDROGEN AND AIR
ARE RUN ON EITHER SIDE OF A MEMBRANE.
THE MEMBRANE INDUCES THE HYDROGEN AND OXYGEN ATOMS
TO COMBINE IN A WAY THAT PRODUCES WATER AND ENERGY.
THE CELL HAS NO MOVING PARTS,
RUNS SLIGHTLY WARM TO THE TOUCH,
AND, AS LONG AS HYDROGEN AND AIR ARE PROVIDED,
CAN'T RUN DOWN LIKE A BATTERY.
THE IDEA HAS BEEN AROUND FOR A LONG TIME
BUT, UNTIL RECENTLY,
WAS TOO INEFFICIENT TO BE PRACTICAL.
THEN ONE DAY, AN ENGINEER AT BALLARD SYSTEMS
LOOKED AT A NEW KIND OF MEMBRANE
THAT HAD BEEN SITTING ON HIS WORKBENCH FOR MONTHS.
WHEN HE TESTED IT,
HE FOUND THAT THE CELLS
PRODUCED FOUR TIMES AS MUCH POWER.
SO FAR, FUEL CELL TECHNOLOGY
IS STILL IN THE TESTING STAGE,
AND WITH SO MUCH INVESTED
IN THE OLD GASOLINE-BURNING TECHNOLOGY,
IT MAY BE A WHILE YET BEFORE WE DRIVE FUEL CELL CARS.
BUT WITH THE CONSTANT THREATS
OF RISING OIL PRICES AND POLLUTION,
THERE'S NEVER BEEN A BETTER TIME FOR A REPLACEMENT.
FIRE:
THE GLOW OF ITS HEAT AND LIGHT SUSTAINS US.
IT TRANSFORMS SAND INTO GLASS
AND IRON ORE INTO STEEL.
IT ALSO DESTROYS HOMES AND TAKES LIVES.
THE ANCIENTS SAW IT AS ONE OF NATURE'S ELEMENTAL FORCES.
UNDERNEATH ALL THE SMOKE AND FLAME,
FIRE IS JUST A CHEMICAL REACTION.
THE FIRST INGREDIENT IS FUEL,
LIKE WOOD OR CANDLE WAX.
THE SECOND INGREDIENT IS OXYGEN,
PLENTIFUL IN THE AIR.
ADD THE LAST INGREDIENT, A SPARK OF HIGH HEAT,
AND THE REACTION BEGINS.
BONDS BETWEEN MOLECULES ARE BROKEN
AND REMADE AS THE FUEL COMBINES WITH THE OXYGEN,
RELEASING THE ENERGY STORED IN THE FUEL
AS HEAT AND LIGHT.
THAT ENERGY KEEPS THE REACTION GOING
AS MORE FUEL IS CONSUMED AND SO ON.
TAKE AWAY ANY OF THE THREE INGREDIENTS--
HEAT, FUEL, OR OXYGEN--
AND THE FIRE GOES OUT.
THE JOB OF REMOVING ONE OF THOSE INGREDIENTS
FALLS TO THESE GUYS, FIREFIGHTERS.
THEY'LL SPRAY WATER TO SMOTHER AND COOL THE FLAMES,
DUMP CHEMICAL GELS TO CUT THE FIRE OFF FROM OXYGEN,
DIG TRENCHES TO CUT THE FIRE OFF FROM FUEL,
BUT IN THE END,
MAN CAN'T ALWAYS CONTROL THE REACTION.
IN THE WILD,
FIRES OCCUR ON AN EPIC SCALE.
IN 1988, YELLOWSTONE NATIONAL PARK
SUFFERED ONE OF THE MOST EXTREME WILDFIRES IN HISTORY.
15,000 FIREFIGHTERS BATTLED A WALL OF FLAME
200 FEET HIGH AND OVER 1,000 DEGREES.
IT WAS A FIRE SO BIG THAT IT CREATED ITS OWN WEATHER.
FAST-RISING WARM AIR CREATED THUNDERSTORMS
AND HURRICANE-FORCE WINDS,
WHICH SUCKED IN FRESH AIR, MORE OXYGEN FOR THE BLAZE.
AT ONE POINT, THE FIRE BURNED THROUGH 14 MILES IN FOUR HOURS,
DESPITE ATTACK FROM THE GROUND AND FROM THE AIR.
AFTER THREE MONTHS,
THE FIRE HAD SCORCHED AN AREA THE SIZE OF NEW YORK CITY.
IRONICALLY, THIS FIRE HIGHLIGHTED
THE DOWNSIDE TO SMOKEY THE BEAR
AND 50 YEARS OF TOTAL FIRE PREVENTION.
OVER THE YEARS, DEBRIS LIKE LEAVES AND NEEDLES
ACCUMULATES ON THE FOREST FLOOR.
SMALL, FREQUENT FIRES
ORDINARILY BURN THIS SO-CALLED DUFF AWAY
IN A NATURAL CYCLE.
BY PREVENTING THESE FIRES, RANGERS WERE SETTING THE STAGE
FOR A MASSIVE, UNCONTROLLABLE BLAZE.
TODAY FOREST MANAGERS ACTUALLY SET FIRES
TO CONTROL THE BUILDUP OF DUFF
AND TO FIGHT EXISTING FIRES.
IN THE ONGOING WAR BETWEEN PEOPLE AND FIRE,
UNDERSTANDING THIS MOST DRAMATIC OF CHEMICAL REACTIONS
IS VITAL.
HOW DO YOU DESCRIBE THE SMELL OF A SUNNY AFTERNOON
OR A NEWBORN BABY?
THE HUMAN BODY CAN DETECT OVER 10,000 SMELLS
THAT LANGUAGE ISN'T EQUIPPED TO DESCRIBE.
SMELL IS A CHEMICAL SENSE.
WE ARE LITERALLY BATHED IN ODOR MOLECULES.
WITH EVERY BREATH,
THESE MOLECULES TRAVEL UP OUR NOSTRILS
TO A SMALL PATCH AT THE TOP OF THE NOSE
COVERED IN NERVE ENDINGS.
EACH NERVE ENDING IS PACKED WITH RECEPTACLES
SHAPED FOR ONLY ONE TYPE OF MOLECULE.
WHEN A MOLECULE FITS INTO ONE OF THESE RECEPTORS,
AN ELECTRICAL SIGNAL IS SENT TO THE BRAIN.
THE PART OF OUR BRAIN THAT PROCESSES THESE SIGNALS
ALSO PROCESSES EMOTIONS AND MEMORIES.
THIS IS WHY WE CAN BE FLOODED WITH FEELINGS
BY A FAMILIAR SCENT.
THE PLEASURE WE DERIVE FROM FOOD
IS A COMBINATION OF OUR TWO CHEMICAL SENSES,
SMELL AND TASTE.
THAT'S WHY A STOPPED-UP NOSE
MAKES FOOD TASTE BLAND.
OUR TONGUES HAVE OVER 9,000 TASTE BUDS.
WITH ONLY A FEW MOLECULES,
THEY CAN TELL US WHETHER SOMETHING'S SOUR, BITTER,
SALTY, OR SWEET.
OUR CHEMOSENSES ARE AMONG THE DULLEST IN THE ANIMAL WORLD.
MAN'S BEST FRIEND
HAPPENS TO HAVE SOME OF THE SHARPEST,
AND WE'VE LEARNED TO USE THIS TO OUR ADVANTAGE.
DOGS HELP US FIND MISSING PERSONS,
ARSON EVIDENCE, EVEN SMUGGLED DRUGS.
IN 1996 ALONE, 450 U.S. CUSTOMS DOGS
FOUND DRUGS VALUED AT $2 BILLION.
A DOG'S NOSE WORKS THE SAME AS OURS,
BUT IT HAS 44 TIMES THE NUMBER OF CHEMICAL RECEPTORS
AND AN OLFACTORY BULB IN ITS BRAIN
FOUR TIMES THE SIZE OF OURS.
DOGS USE SCENTS TO SEND AND RECEIVE INFORMATION
ABOUT THE SEX, SIZE, HEALTH,
AND SOCIAL STATUS OF EACH OTHER.
THE RESULT IS A SENSE OF SMELL
100 TIMES AS POWERFUL AS OUR OWN.
THAT NOSE MAY BE USED TO SAVE LIVES.
DOCTORS IN TALLAHASSEE
HAVE FOUND THAT DOGS CAN SMELL SKIN CANCER.
DOCTORS DON'T YET KNOW HOW THEY DO THIS.
THE DOGS MAY SENSE SOME VOLATILE CHEMICAL
RELATED TO THE CANCER GROWTH.
MAN'S BEST FRIEND, INDEED.
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provided by the U.S. Department of Education.
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