Original subtitles

Narrator: IN THE EARLY DAYS OF THE RAILROAD,

TRAIN RAILS WERE MADE OF EITHER CAST IRON OR WROUGHT IRON.

CAST IRON WAS TOO BRITTLE AND WOULD BREAK EASILY.

WROUGHT IRON WAS TOO SOFT AND WOULD WEAR OUT TOO QUICKLY.

SO STEEL EVENTUALLY BECAME AND REMAINED

THE TRAIN-RAIL METAL OF CHOICE.

THE TRAIN WHEEL'S RIM RUNS ON THE INSIDE OF THE RAIL

TO KEEP THE TRAIN ON THE TRACK.

THIS PLANT MAKES TRAIN RAILS ENTIRELY OUT OF RECYCLED STEEL

FROM SCRAPYARDS, FOOD CANS,

AND RECYCLED PIECES FROM THE RAIL-MAKING PROCESS ITSELF.

ELECTROMAGNETS PICK UP THE SCRAP

AND DUMP IT IN A CHARGING BUCKET.

A TRUCK HAULS THE BUCKET INSIDE,

WHERE A CRANE DROPS THE CONTENTS INTO A FURNACE.

AN INTENSE ELECTRIC CURRENT

MELTS THE SCRAP STEEL AT 3,000 DEGREES FAHRENHEIT.

IT THEN FLOWS INTO A LARGE BRICK-LINED LADLE,

WHERE THEY ADD CARBON, MANGANESE, AND OTHER ELEMENTS

TO MAKE THE STEEL MORE DURABLE.

THE ALLOY THEN RUNS DOWN A CERAMIC TUBE

THAT SHIELDS IT FROM EXPOSURE TO OXYGEN,

WHICH WOULD RUIN THE METAL.

FROM THERE, THE MOLTEN METAL FLOWS INTO MOLDS,

WHICH EXTRUDE IT INTO CONTINUOUS RECTANGULAR BLOCKS

CALLED BLOOMS.

ACETYLENE TORCHES CUT EACH BLOOM INTO 12-FOOT LENGTHS.

A CRANE THEN TRANSFERS THE BLOOMS TO A FURNACE,

WHICH, OVER THE NEXT FIVE TO SEVEN HOURS,

REHEATS THEM TO 2,300 DEGREES FAHRENHEIT.

THIS SOFTENS THE STEEL FOR FURTHER SHAPING.

THEN THE REHEATED BLOOMS ENTER A MACHINE CALLED A ROLLING MILL,

WHICH ELONGATES EACH BLOOM, MORE THAN QUADRUPLING ITS LENGTH.

A SHEAR THEN SLICES THE LONGER, THINNER BLOOMS INTO FOUR PIECES.

THE PIECES NOW GO INTO ANOTHER FURNACE FOR REHEATING.

THIS PREPS THEM FOR THE NEXT SET OF ROLLING MILLS,

WHICH WILL GRADUALLY FORM THEM TO THE FINAL RAIL SHAPE.

DIFFERENT RAILROADS USED TO USE DIFFERENT-SHAPED RAILS,

WHICH REQUIRED CHANGING THE TRAIN'S WHEELS

WHEN PASSING FROM ONE RAILWAY TO ANOTHER.

BY THE TURN OF THE 20th CENTURY,

THE T-SHAPED RAIL BECAME THE INDUSTRY STANDARD

AND REMAINS SO TODAY.

FOR THE FINAL SHAPING, EACH STEEL RAIL

PASSES SEVERAL TIMES THROUGH THREE CONSECUTIVE MILLS.

THIS IS WHAT A MILL'S ROLLERS LOOK LIKE.

AND HERE'S THE STANDARD "T" SHAPE

TO WHICH THEY FORM THE STEEL.

NEXT, A SAW SLICES OFF ABOUT 12 INCHES TO SQUARE OFF THE ENDS.

THE CUT-OFF PIECES GO BACK TO THE SCRAPYARD.

THE RAILS, MEANWHILE, ARE LAID OUT

UNTIL THEY COOL TO ABOUT 930 DEGREES FAHRENHEIT.

THEN AN ELECTROMAGNET PILES THEM IN A HOLDING BOX,

WHERE THEY SIT FOR 10 HOURS

UNTIL THEY COOL OFF TO ABOUT 190 DEGREES FAHRENHEIT.

WHEN THEY COME OUT OF THE BOX,

THEY RUN THROUGH TWO SETS OF ROLLERS.

THE FIRST SET FLEXES THE RAIL VERTICALLY.

THE SECOND, HORIZONTALLY.

THIS FLEXING PROCESS

STRAIGHTENS OUT THE RAILS, WHICH CURVE SLIGHTLY

DUE TO ALL THAT HEATING, SHAPING, AND COOLING.

NEXT, EACH RAIL PASSES OVER A MIRROR,

ENABLING INSPECTORS TO EXAMINE THE BOTTOM, AS WELL AS THE TOP.

FINALLY, A SAW CUTS THE RAILS

TO WHATEVER SIZE THE RAILWAY ORDERED --

MOST OFTEN THE STANDARD LENGTH OF 82 FEET.

THE QUALITY-CONTROL DEPARTMENT MEASURES RANDOM SAMPLES

TO MAKE SURE ALL THE DIMENSIONS ARE PRECISE.

EVERY RAIL BEARS A NUMBER

IDENTIFYING THE BATCH OF STEEL FROM WHICH IT CAME.

IN THE EVENT OF A PROBLEM, THAT NUMBER

LETS THEM TRACE ALL THE RAILS MADE FROM THE SAME BATCH.

IT'S A SYSTEM THAT ENSURES A SAFE, SMOOTH RIDE.

Narrator: IN REGIONS WHERE FRESH DRINKING WATER IS LIMITED,

DESALINATION PLANTS REMOVE SALT FROM SEAWATER,

CONVERTING IT INTO FRESHWATER SUITABLE FOR HUMAN CONSUMPTION.

THERE ARE MORE THAN 13,000 DESALINATION PLANTS WORLDWIDE,

PRODUCING 12 BILLION GALLONS OF WATER A DAY.

THE DESALINATION PLANT THAT PRODUCED THIS DRINKABLE WATER

IS LOCATED RIGHT NEXT TO AN ELECTRICAL POWER PLANT

WHICH USES SEAWATER TO COOL DOWN ITS CONDENSERS.

POST-COOLING, THE WATER TRAVELS VIA UNDERGROUND PIPES

TO THE DESALINATION PLANT.

BEFORE SALT EXTRACTION, THE WATER IS PRETREATED

IN A MULTIPHASE CLEANING PROCESS.

FIRST, THE WATER FLOWS THROUGH SCREENS

THAT FILTER OUT LARGE DEBRIS.

FROM THERE, IT FLOWS INTO BASINS

FOR THE FIRST PRETREATMENT STAGE.

AS LARGE PADDLES AGITATE THE WATER,

THE PLANT ADDS TWO CHEMICALS --

SODIUM HYPOCHLORITE, A DISINFECTANT,

AND FERRIC CHLORIDE, A COAGULANT.

THE COAGULANT BINDS TOGETHER SAND

AND OTHER TINY PARTICLES OF DEBRIS,

FORMING HEAVIER CLUMPS THAT SINK TO THE BOTTOM.

THIS REMOVES A SIGNIFICANT PORTION OF DIRT FROM THE WATER,

BUT IT'S STILL FAR FROM BEING CRYSTAL CLEAR.

THE WATER NOW MOVES INTO ANOTHER SET OF BASINS

FOR THE SECOND PRETREATMENT PHASE -- SAND FILTERING.

INSIDE EACH SAND FILTER,

REGULATED BY VARIOUS PRESSURE AND FLOW GAUGES,

A STEADY STREAM OF AIR

CONTINUALLY MOVES SAND IN A CIRCULAR MOTION.

THE SEAWATER ENTERS AT THE BOTTOM OF EACH FILTER

AND FLOWS TO THE TOP.

AS THE SAND MOVES DOWNWARD AGAINST THE RISING WATER,

THE DIRT PARTICLES ATTACH TO THE SAND.

THE SEAWATER NOW LOOKS CLEAN

BUT STILL CONTAINS MICROSCOPIC PARTICLES.

SO IT ENTERS THE FINAL PRETREATMENT PHASE.

THIS TIME, THE FILTERING MEDIUM IS DIATOMACEOUS EARTH,

A POWDERED ROCK THAT CONTAINS ALGAE FOSSILS.

FINER THAN SAND, IT FILTERS OUT THOSE MICROSCOPIC PARTICLES.

THE SEAWATER IS NOW PERFECTLY CLEAN

AND READY FOR SALT EXTRACTION.

THEY DO THAT USING MEMBRANES --

CYLINDERS CONTAINING LAYERS OF PLASTIC SHEETS

THAT HAVE PORES .001 THE DIAMETER OF A HUMAN HAIR,

SMALL ENOUGH TO TRAP MICROSCOPIC SALT CRYSTALS.

THE PLANT PUMPS THE CLEAN SALTWATER

UNDER EXTREMELY HIGH PRESSURE THROUGH LONG TUBES,

EACH OF WHICH CONTAINS EIGHT MEMBRANES.

BY THE TIME THE WATER PASSES THROUGH ALL THE MEMBRANES

AND REACHES THE CENTER OF THE TUBE, IT'S COMPLETELY SALT-FREE.

PLANT PERSONNEL AND A SLEW OF SOPHISTICATED INSTRUMENTS

CONTINUALLY MONITOR EVERY ONE OF THE SYSTEM'S 10,000 MEMBRANES.

MEANWHILE, THE PLANT SENDS THE DEBRIS REMOVED EARLIER

TO LARGE WASTE BASINS

FOR ANOTHER ROUND OF CHEMICAL TREATMENT.

AFTER THE SOLIDS SETTLE TO THE BOTTOM,

THE DIRTY WATER GOES BACK TO THE FRONT OF THE PLANT

TO BE CLEANED AND RECYCLED.

PRESSURE ROLLERS SQUEEZE THE REMAINING WATER

OUT OF THE SOLIDS.

TRUCKS THEN TRANSPORT THE DRY SOLIDS TO A LANDFILL.

THE EXTRACTED SALT, MEANWHILE, GOES TO THE POWER PLANT,

WHICH DILUTES IT, THEN RETURNS IT TO THE SEA

IN A WAY THAT DOESN'T UPSET THE WATER'S NATURAL SALINITY LEVEL.

PROCESSING SALTWATER INTO FRESHWATER

STRIPS AWAY THE WATER'S NATURAL MINERALS.

NOT REPLACING THEM WOULD CREATE TWO PROBLEMS.

FIRST, THE WATER WOULDN'T TASTE RIGHT.

SECOND, IT WOULD DAMAGE METAL PIPES

BY AGGRESSIVELY TRYING TO REPLACE THE MISSING MINERALS.

THEREFORE, THE PLANT ADDS LIQUID LIME AND CARBON DIOXIDE

TO THE WATER.

THESE TWO ELEMENTS ADJUST THE pH LEVEL AND RAISE THE ALKALINITY,

RESTORING THE MINERALS AND NATURAL TASTE.

Narrator: WORLD WAR II VETERANS DISABLED IN COMBAT

WERE THE FIRST TO RACE IN WHEELCHAIRS.

BUT THOSE CHAIRS WERE CLUNKY, STEEL MODELS.

FAST-FORWARD TO TODAY AND WHEELCHAIR RACING

IS A SERIOUS SPORT WITH AERODYNAMIC CHAIRS.

THESE CHAIRS HAVE ELONGATED MAINFRAMES

AND THREE WHEELS INSTEAD OF FOUR.

THIS MODERN RACING CHAIR IS TAILORED

TO THE ATHLETE'S PHYSIQUE, SPECIFIC DISABILITY,

AND SKILL LEVEL.

THEY BEGIN BY TAKING DETAILED MEASUREMENTS OF THE ATHLETE

AS SHE SITS IN A DEMO CHAIR.

THEY MEASURE THE WIDTH AND HEIGHT OF HER KNEES

TO DETERMINE THE BEST SEATING POSITION.

THEY CHECK THE BALANCE POINT

TO DECIDE HOW THE REAR-WHEEL AXLE SHOULD BE POSITIONED,

AND THEY MEASURE HER ARMS SO PUSH RIMS CAN BE SIZED FOR HER.

THEY THEN PRODUCE A DIGITAL DRAWING

OF THE RACING WHEELCHAIR,

COMPLETE WITH ANY EXTRAS REQUESTED BY THE ATHLETE.

THE FABRICATOR SELECTS THE APPROPRIATE ALUMINUM TUBING

AND CUTS IT TO THE DESIRED LENGTH.

THIS ONE WILL BE THE MAIN TUBE FOR THE RACING CHAIR'S FRAME.

ROLLERS CURVE THE TUBE SLIGHTLY AT ONE END

SO THE FRAMEWORK WILL ACCOMMODATE THE SEAT.

A PRESS THEN FLATTENS THE TUBE QUITE A BIT.

THIS STIFFENS THE METAL

AND WILL MAKE THE RACING-CHAIR FRAME MORE AERODYNAMIC.

THIS SMALL TUBE, WHICH THEY WELD TO THE MAIN TUBE,

WILL HOLD THE RACING CHAIR'S STEERING FORK.

HE NOW TAPES A STEERING MECHANISM FOR THE FRONT WHEEL

ONTO THE FRAMEWORK

AND CONFIRMS THAT ITS PLACEMENT IS EXACT BEFORE WELDING.

THIS DEVICE WILL KEEP THE FRONT WHEEL ON AUTOPILOT,

FREEING THE RACER'S HANDS TO PUSH THE REAR WHEELS.

THE WELDER NOW POSITIONS THE OTHER END OF THE MAIN TUBE

PERPENDICULAR TO THE WHEEL AXLE.

HE INCHES THE TUBE TOWARDS THE CENTER OF THE AXLE

UNTIL IT'S RIGHT ON THE MARK.

HE WELDS THE AXLE TO THE MAIN TUBE,

GIVING THE FRAMEWORK A "T" PROFILE.

TEMPORARY WHEELS LIFT THE AXLE

SO HE CAN INSTALL THE SEAT FRAME.

THEN A HYDRAULIC MACHINE BENDS AN ALUMINUM TUBE

INTO A "U" SHAPE TO MAKE THE RACING CHAIR'S SEAT FRAME.

HE POSITIONS THE SEAT FRAME ON THE REAR AXLE

AND DOES A FEW MORE WELDS.

FINALLY, HE INSTALLS FENDERS ON THE WHEELS.

THE MAIN FRAMEWORK OF THIS RACING WHEELCHAIR IS COMPLETE.

BUT TO MAKE IT LOOK FLASHY, THEY SPRAY-PAINT IT RED.

THIS IS A POWDER COATING.

IT'S A THERMOPLASTIC PAINT

THAT'S TOUGHER THAN THE CONVENTIONAL KIND.

NEXT, THIS MACHINE ROLLS THE PUSH RIMS,

WHICH THE ATHLETE USES TO PROPEL THE WHEELCHAIR.

THEY WELD ON PEGS FOR ATTACHING THE RIMS TO THE WHEELS,

THEN GLUE A RUBBER SLEEVE ONTO EACH RIM.

THEY WRAP IT IN TAPE TO CLAMP THE TWO AS THE GLUE DRIES.

THE TAPE STAYS ON

UNTIL THE CHAIR IS DELIVERED TO THE CUSTOMER.

THEY INSTALL THE REAR WHEELS AT AN ANGLE

TO MAKE THE RACING CHAIR MORE STABLE WHEN CORNERING.

THEY ADD PADDING FOR THE ATHLETE'S KNEES,

THEN ASSEMBLE THE NYLON SEAT TO THE CHAIR.

NEXT COMES THE FRONT-WHEEL STEERING FORK AND HANDLE.

THEY COMPLETE THE ASSEMBLY WITH A SPRING-LOADED CYLINDER.

THAT'S PART OF THE STEERING AUTOPILOT SYSTEM.

AFTER TESTING THE STEERING FORK, THEY INSTALL THE FRONT WHEEL,

WHICH IS SMALLER THAN THE REAR TWO.

ONCE IT'S BEEN EQUIPPED WITH BRAKES,

THIS CUSTOM RACING CHAIR

IS READY TO TAKE ON THE COMPETITION.

AN ELITE ATHLETE WILL BUY A NEW RACING CHAIR EVERY YEAR.

SOME CHOOSE REAR WHEELS MADE OF LIGHTWEIGHT CARBON FIBER

BECAUSE ANY ADVANTAGE IS WELCOME IN THE PUSH TO WIN.

Narrator: PARQUETRY WAS INVENTED

IN FRANCE IN THE 1600s AS AN ALTERNATIVE

TO HIGH-MAINTENANCE MARBLE FLOORING.

IT'S MADE FROM SMALL PIECES OF WOOD

BONDED TOGETHER IN A GEOMETRIC PATTERN.

THE MOST COMMON MOTIF IS SQUARES.

BUT IT ALSO COMES IN OTHER PATTERNS,

SUCH AS HERRINGBONE, LOZENGES, AND TRIANGLES.

PARQUETRY CAN BE MADE OF LAMINATE OR PLYWOOD.

HOWEVER, THE BEST-QUALITY FLOORING

IS MADE FROM GENUINE WOOD, SUCH AS OAK, MAPLE, OR YELLOW BIRCH.

THE FACTORY FIRST CUTS THE WOOD INTO PLANKS,

MEASURING 2 TO 5 INCHES WIDE BY ABOUT A YARD LONG.

A DRUM SAW THEN CUTS EACH PLANK

INTO 6 BLOCKS ABOUT 6 INCHES LONG

WHILE AN INSPECTOR DISCARDS ANY MISSHAPEN ONES.

THE BLOCKS THEN MOVE THROUGH A PLANER

THAT SHAVES A FINE LAYER OFF BOTH SIDES.

THIS REDUCES THE BLOCKS TO A THICKNESS OF JUST UNDER AN INCH

AND SMOOTHES THE TOP AND BOTTOM SURFACES.

NEXT, THE BLOCKS RUN THROUGH A SAW

WITH 10 BLADES THAT SLICE THEM INTO STRIPS

MEASURING .3 INCHES WIDE BY 6.2 INCHES LONG.

QUALITY CONTROLLERS REMOVE ANY STRIPS

WITH INCONSISTENT THICKNESS,

WHICH ARE USUALLY THE ONES CUT FROM THE BLOCK'S EXTREMITIES.

THE GOOD STRIPS CONTINUE ON TO ANOTHER AREA,

WHERE THEY UNDERGO A MORE THOROUGH

QUALITY-CONTROL INSPECTION.

A WORKER CHECKS THE TOPS AND BOTTOMS,

THEN LINES THEM UP ON A CONVEYOR BELT GOOD-SIDE UP.

SHE ALSO DISCARDS ANY SUBSTANDARD STRIPS

THAT MAY HAVE SLIPPED PAST THE FIRST INSPECTION.

THE CONVEYOR BELT THEN FLIPS THE STRIPS OVER.

THIS POSITIONS THE STRIPS UNDERSIDE FACING UPWARD.

SAWS THEN CUT TWO PARALLEL GROOVES THROUGH THEM.

THESE GROOVES ARE SET .9 INCHES IN FROM THE EDGE...

...AND ARE JUST DEEP ENOUGH TO HOLD A THIN ALUMINUM WIRE

THAT'LL CONNECT STRIPS TOGETHER TO FORM TILES.

THE NEXT MACHINE DISPENSES THE PARALLEL WIRES.

A WHEEL PUSHES THE WIRES DEEP INSIDE THEIR RESPECTIVE GROOVES.

AFTER EVERY SEVEN STRIPS,

THE MACHINE CUTS THE WIRES AND STARTS NEW ONES.

THE 7-LENGTH STRIPS FORM A 6-INCH-SQUARE TILE.

AN END-MATCHING MACHINE NOW SQUARES EACH TILE

SO THAT THE FOUR CORNERS ARE PRECISELY 90 DEGREES.

THEN IT CARVES TONGUES ON TWO OF THE TILE'S EDGES

AND GROOVES INTO THE OTHER TWO.

FOUR TILE FEEDERS THEN DROP TILES INTO AN ASSEMBLY MACHINE

THAT INSERTS THE TONGUES INTO THE GROOVES.

THE MACHINE THEN APPLIES HOT GLUE

WHICH BONDS THE FOUR TILES INTO ONE LARGER TILE

MEASURING 12x12 INCHES.

THE TILES ARE NOW READY FOR VARNISHING.

FEEDERS DROP THEM ONTO THE AUTOMATED VARNISHING LINE.

THE TILE SURFACE GETS A SANDING.

ROLLERS THEN APPLY AN EVEN COAT OF VARNISH.

FROM THERE, THE TILES IMMEDIATELY PASS UNDER

ULTRAVIOLET LIGHT.

THIS DRIES THE VARNISH WITHIN A SECOND.

THEN THE PROCESS REPEATS THREE MORE TIMES

FOR A TOTAL OF FOUR COATS OF VARNISH.

WORKERS THEN STACK THEM IN 10s,

AT THE SAME TIME DOING A FINAL INSPECTION

AND DISCARDING ANY TILE THAT HAS A LESS-THAN-PERFECT FINISH.

ON THE PACKAGING LINE,

EACH STACK GETS A LABEL AND CLEAR PLASTIC WRAPPING.

AN OVEN SHRINKS THE PLASTIC TIGHTLY AROUND THE TILES.

THOSE FOUR COATS OF VARNISH MADE THIS PARQUETRY SUPERDURABLE,

AND BECAUSE IT'S REAL WOOD,

WHEN THE MANY YEARS OF WEAR DO BEGIN TO SHOW,

YOU CAN SIMPLY REFINISH THE FLOOR TO ITS ORIGINAL SPLENDOR.

--Captions by VITAC-- www.vitac.com

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS

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