"Annenberg Media" "¶" "CAPTIONING IS MADE POSSIBLE BY THE ANNENBERG/CPB PROJECT" "I HAVE A COLD TODAY, SO I WILL START BY MAKING" "A CUP OF TEA." "OBVIOUSLY, THAT'S GOING TO BE ICED TEA." "HOT OR COLD DEPENDS ON HOW YOU LOOK AT IT." "WE ALL KNOW THAT IT'S EASY" "TO MAKE SOMETHING WARM." "IT'S HARD" "TO MAKE SOMETHING COLD." "WE'VE KNOWN ABOUT FIRE" "SINCE BEFORE THE DAWN OF HISTORY." "THE REFRIGERATOR IS BARELY OLDER" "THAN THE OLDEST LIVING PERSON." "TODAY, WE WILL FIND OUT" "HOW TO GO ABOUT MAKING THINGS COLD." "HOW COLD IS COLD?" "THE STUFF IN HERE IS AT A TEMPERATURE SO LOW" "THAT THE VERY AIR ITSELF BECOMES A LIQUID." "NOW THAT'S REALLY COLD." "TODAY WE WILL FIND OUT HOW TO MAKE THAT." "THESE EXTRAORDINARY MACHINES WORK WONDERS" "WITH THE MOST COMMON GAS IN THE ATMOSPHERE," "ORDINARY AIR." "THAT'S THE RAW MATERIAL OF THIS PLANT" "THE ORDINARY URBAN AIR" "OF A MODERN INDUSTRIAL ENVIRONMENT." "THESE MACHINES COMPRESS THAT AIR" "AND NECESSARILY HEAT IT AS WELL." "THE AIR IS COOLED BACK DOWN FOR THE FIRST TIME." "BEFORE THESE MACHINES ARE FINISHED WITH IT," "THE AIR WILL BE COMPRESSED AND COOLED FURTHER" "FOUR TIMES IN ALL." "FINALLY, INSIDE THIS COLUMN, ORDINARY AIR," "COMMONLY AN ODORLESS AND COLORLESS MIXTURE" "OF MOSTLY NITROGEN AND OXYGEN," "WILL BE TRANSFORMED." "FINALLY, IT WILL BE LIQUID." "THE AIR ENTERS A CONFIGURATION OF FILTERS." "IN THE PROCESS, BEFORE COMING OUT AS A LIQUID," "ITS TEMPERATURE HAS BEEN LOWERED EXTREMELY." "WHEN IT DOES COME OUT, IT CAN BE FULL OF SURPRISES." "LIQUID OXYGEN LOOKS REFRESHING," "BUT FOR ANYONE FOOLISH ENOUGH TO TAKE THE PLUNGE," "REMEMBER THAT IT'S 186 DEGREES BELOW ZERO CELSIUS." "IN THE BUSINESS OF CHANGING AIR INTO LIQUID," "LOOKS CAN BE DECEIVING." "FOR EXAMPLE," "AT COMMON TEMPERATURES AND PRESSURES," "WATER IS A LIQUID, AND AIR AN INVISIBLE GAS." "BUT AT THE TEMPERATURES FOUND IN THESE PARTS," "AIR IS A LIQUID." "IT'S VAPOR IS EASILY SEEN." "WATER FREEZES SOLID IN THE NOONDAY SUN." "IN FACTORIES AND NATURE ALIKE," "THE WONDERS OF NITROGEN AND OXYGEN" "MAY NEVER CEASE TO AMAZE." "THAT'S BECAUSE EVERY SUBSTANCE IN THE WORLD," "EVEN AIR ITSELF," "CAN BE A SOLID, A LIQUID, OR A GAS." "DEPENDING ON TWO VARIABLES, PRESSURE AND TEMPERATURE," "MATTER FORMS SOLIDS, LIQUIDS, OR GASES." "THESE ARE THE STATES OF MATTER." "ABOUT 150 YEARS AGO," "MICHAEL FARADAY OFFERED THE FIRST RATIONAL EXPLANATION" "OF THE STATES OF MATTER." "BORN INTO POVERTY RATHER THAN PRIVILEGE," "YOUNG FARADAY NEVERTHELESS ENTERED THE WORLD OF SCIENCE." "ONCE HE WAS FINALLY WELL-ESTABLISHED" "WITHIN THE BRITISH ROYAL INSTITUTION," "HE ROSE TO HEIGHTS UNREACHED SINCE SIR ISAAC NEWTON." "BUT HE SOON DISCOVERED" "THAT EXPERIMENTING WITH STATES OF MATTER" "COULD BE A RISKY BUSINESS." "FOR EXAMPLE, IN 1823," "EXPERIMENTING WITH CHLORINE GAS" "LIBERATED IN A SEALED, HEATED GLASS TUBE," "FARADAY OBSERVED A FLUID FORMING" "IN THE COOLER END OF THE TUBE." "FILING THE TUBE OPEN TO INVESTIGATE" "MAY HAVE BEEN UNWISE." "[EXPLOSION]" "BUT MICHAEL FARADAY DIDN'T LOSE HIS BRITISH COOL." "INSTEAD, HE'D FOUND LIQUID CHLORINE." "HAVING LIQUEFIED ONE GAS, CHLORINE," "HE WAS EAGER TO DO THE SAME TO OTHERS." "PERHAPS TOO EAGER." "[EXPLOSION]" "BUT DESPITE THE PRESSURES OF HIS WORK," "MICHAEL FARADAY SURVIVED." "HIS SURVIVING DOCUMENTS PROVE HE WAS THE FIRST TO REALIZE" "THAT THE SAME MATTER CAN EXIST" "IN EACH FUNDAMENTAL STATE" "GAS, LIQUID, AND SOLID." "BUT THAT EXISTENCE WOULD TAKE" "THE RIGHT TEMPERATURE AND PRESSURE." "ATLOWTEMPERATURE, MATTER IS USUALLY SOLID" "ASTATEIN WHICH MOLECULESFORM" "A RIGID GEOMETRICAL LATTICE," "ALTHOUGH CLOSE INSPECTION SHOWS THEY'RE ALWAYS MOVING." "ATHIGHERTEMPERATURES," "SOLIDSMELT ANDBECOMELIQUIDS." "NOWTHEMOLECULES AREMUCHLESSORDERLY" "ANDFLOWEASILY PASTEACHOTHER." "RAISETHETEMPERATUREFURTHER," "ANDLIQUIDSEVAPORATE INTOGASES" "A STATE IN WHICH MOLECULES DON'T ADHERE TO ONE ANOTHER," "BUT BOUNCE AROUND INSTEAD." "THE TEMPERATURE AT WHICH THESE CHANGES OF STATE OCCUR" "DEPENDONTHEPRESSURE FOREACHSUBSTANCE." "ANDATLOWERPRESSURES," "THESE CHANGES CAN TAKE PLACE ATLOWERTEMPERATURES." "DEPENDINGONTHEPRESSURE ANDTEMPERATURE," "EACH SUBSTANCE IS EITHER A SOLID, A LIQUID, OR A GAS." "BUT ONLY UP TO A CERTAIN POINT" "THE CRITICAL POINT." "ABOVE THAT CRITICAL POINT OF TEMPERATURE AND PRESSURE," "LIQUID AND GAS NO LONGER EXIST AS SEPARATE STATES OF MATTER." "THE CRITICAL POINT," "WHICH IS DIFFERENT FOR EACH SUBSTANCE," "WAS DISCOVERED BY A PARISIAN PHYSICIST," "CHARLES CAGNIARD LA TOUR." "IT WAS A STARTLING DISCOVERY," "MADE WHEN HE HEATED LIQUID ETHER" "IN A SEALED GLASS TUBE." "WHAT HE SAW CAN BE ILLUSTRATED WITH LIQUID ETHANE." "AS THE CONTAINER IS HEATED," "THE SURFACE THAT SEPARATES THE LIQUID FROM THE VAPOR VANISHES." "ABOVE THE CRITICAL POINT," "THERE'S NEITHER LIQUID NOR VAPOR." "INSTEAD, THERE'S ONE CONTINUOUS FLUID." "AS THE FLUID COOLS BACK DOWN TOWARD THE CRITICAL POINT," "STRIATIONS OF DENSITY BEGIN TO APPEAR." "THE FLUID BECOMES MOMENTARILY OPAQUE" "BECAUSE TINY DROPS OF LIQUID" "FORM JUST LARGE ENOUGH TO SCATTER LIGHT." "FINALLY, AS THE TEMPERATURE FALLS BELOW THE CRITICAL POINT," "THE MENISCUS REAPPEARS" "AND CLEARLY SHOWS SEPARATE STATES OF LIQUID AND VAPOR." "OBVIOUSLY, THEN..." "BELOWTHECRITICALPOINT," "GASANDLIQUID HAVEDIFFERENTDENSITIES." "ABOVETHETEMPERATURE OFTHECRITICALPOINT," "THERE'SA SINGLE, CONTINUOUSFLUID." "HERE, LIQUID NEVER FORMS," "NO MATTER HOW HIGH THE PRESSURE." "FOR SOME SUBSTANCES," "THE TEMPERATURE HAS TO GET VERY COLD" "TO REACH THE CRITICAL POINT." "OXYGEN, FOR EXAMPLE, HAS A CRITICAL TEMPERATURE" "OF 119 DEGREES BELOW ZERO CELSIUS." "IN ITS LIQUID FORM," "OXYGEN CAN ONLY EXIST AT EVEN LOWER TEMPERATURES." "HOW IS IT POSSIBLE TO COOL ANY SUBSTANCE SO LOW?" "HOW IS IT POSSIBLE FOR SOMETHING" "TO COOL AND TO BOIL AT THE SAME TIME?" "THE ANSWER TO BOTH QUESTIONS" "BEGINS WITH THE PROCESS OF EVAPORATION," "AND THAT BEGAN BEFORE THINGS GOT OUT OF HAND" "IN FACT, EVEN BEFORE THE ENGINE WAS RUNNING." "OH, MERCY." "WHEN THE ENGINE'S COOL," "THE WATER IN THE RADIATOR IS UNDER ORDINARY PRESSURE" "AND AT ROOM TEMPERATURE." "IT'S STILL A LIQUID." "BUT WHEN THE LIQUID BOILS, IT EVAPORATES." "AND EVEN THOUGH IT DOESN'T LOOK IT," "THE LIQUID ALSO COOLS IN THE PROCESS." "COOL, CALM, AND MORE OR LESS COLLECTED," "WATER MOLECULES SWIM AROUND SLOWLY." "HEATED, THEY SWIM FASTER." "THE HIGHER THE TEMPERATURE, THE FASTER THEIR SPEED." "AS THE TEMPERATURE INCREASES," "THE FASTER MOLECULES MANAGE TO ESCAPE" "UNDER THEIR OWN POWER," "WHICH LEAVES THE SLOWER, COOLER MOLECULES LEFT BEHIND." "AT THE SAME TIME, IN THEIR STRUGGLE" "TO ESCAPE THE SLOWER LIQUID MOLECULES LEFT WITHIN," "THE FAST MOLECULES ARE SLOWED AND COOLED AS THEY EVAPORATE." "BOTH THE VAPOR AND LIQUID LEFT BEHIND" "ARE COOLED BY THE EVAPORATION PROCESS." "ON THE SURFACE, THERE MAY BE AN AIR OF UNREALITY TO IT." "THE FACT IS, IN ONE FORM OR ANOTHER," "EVAPORATION HAS KEPT THINGS COOL FOR A VERY LONG TIME." "FOR EXAMPLE, CONSIDER LEONARDO DA VINCI," "A GENIUS WITH ANYTHING HAVING TO DO WITH THE AIR." "HE EVEN INVENTED A SYSTEM TO COOL IT." "FOR THE NEXT 300 YEARS, LEONARDO'S SYSTEM" "WAS AIR CONDITIONING AT ITS BEST." "BUT ON AND ON THROUGH HISTORY," "SCIENTISTS SUCH AS MICHAEL FARADAY" "CONTINUED TO SEARCH FOR THE MEANS" "TO GET THINGS REALLY COLD." "IN THE 19th CENTURY," "THEY FOUND IT IN CARBON DIOXIDE." "THE FIRST STEP" "FROM ROOM TEMPERATURE TO LOW TEMPERATURE" "IS NOT VERY HARD TO TAKE." "IT HAS TO DO WITH THE PECULIAR PROPERTIES" "OF CARBON DIOXIDE." "THE CRITICAL TEMPERATURE OF CARBON DIOXIDE" "IS A LITTLE ABOVE ROOM TEMPERATURE." "IF I HAD CARBON DIOXIDE IN THIS ROOM," "BUT AT HIGH PRESSURE," "IT WOULD BE AN ORDINARY LIQUID." "THAT'S PRECISELY WHAT I HAVE IN THIS CYLINDER." "THE PRESSURE IS ABOVE THE CRITICAL PRESSURE" "OF CARBON DIOXIDE," "ABOUT 73 ATMOSPHERES-- 73 TIMES ATMOSPHERIC PRESSURE." "THE TEMPERATURE IS THAT OF THE ROOM." "UNDER THESE CONDITIONS, CARBON DIOXIDE IS A LIQUID." "IF I OPEN THIS VALVE," "THE RELEASED PRESSURE CREATES A HISS." "THAT LIQUID CARBON DIOXIDE" "IS EVAPORATING" "AND DROPPING IN PRESSURE" "ALONG ITS VAPOR-PRESSURE CURVE" "TO LOW TEMPERATURE." "CARBON DIOXIDE PASSES" "THROUGH ITS TRIPLE POINT," "THE POINT AT WHICH IT FREEZES," "WHILE IT'S WELL ABOVE" "AN ATMOSPHERE OF PRESSURE." "ON THE WAY DOWN, IT FREEZES," "BECOMING DRY ICE." "IT REACHES NEARLY 80 DEGREES BELOW ZERO CELSIUS" "BEFORE REACHING" "THE ATMOSPHERE'S PRESSURE," "STOPPING COOLING." "LET ME SHOW YOU." "OPENING THE VALVE, WE'LL REACH MINUS 80 CELSIUS." "THIS WILL BE LOUD." "LET'S CUT THIS OFF AND SEE WHAT WE'VE GOT." "THAT'S DRY ICE." "GETTING THAT LOW IN TEMPERATURE" "WAS NOT VERY DIFFICULT." "IT WAS STILL AN ARDUOUS TASK" "TO GET DOWN TO THE TEMPERATURE OF LIQUID AIR." "IT WAS NOT THE END." "NO MATTER HOW LONG AND ARDUOUS," "IT WAS NOW TIME FOR FARADAY TO FOCUS ON THE TASK." "THE DISCOVERY OF CARBON DIOXIDE WAS MORE THAN A DRY FACT." "IT WAS THE INSPIRATION HE NEEDED" "TO CONTINUE TO WORK ON LIQUEFYING GAS." "LATER, WHEN HE FOUND TIME TO RECORD HIS ACCOMPLISHMENTS," "THE SCIENTIFIC WORLD TOOK NOTE." "HE HAD LOWERED THE TEMPERATURE OF GASES" "IN A BATH OF DRY ICE AND ETHER." "WHILE THEY WERE COLD, HE HAD COMPRESSED THEM" "TO 40 TIMES THE PRESSURE OF THE ATMOSPHERE." "FARADAY HAD LIQUEFIED EVERY KNOWN GAS" "EXCEPT OXYGEN, NITROGEN, AND HYDROGEN." "LIQUEFACTION FOR THESE GASES WOULD REQUIRE" "COOLING BELOW THEIR CRITICAL TEMPERATURES," "WHICH IS FAR BELOW" "THE TEMPERATURE OF DRY ICE." "ALTHOUGH FARADAY DIDN'T TAKE THE NEXT STEP," "HE HAD SHOWN THE RIGHT DIRECTION" "A STEP-BY-STEP COOLING CALLED THE CASCADE PROCESS." "LIKE WATER FALLING FROM ONE LEVEL TO ANOTHER," "LIQUEFACTION TAKES PLACE" "IN A CASCADE OF LOWERING TEMPERATURES." "ONE LIQUID SERVES AS THE BATH FOR ANOTHER," "COOLING THE NEXT IN TURN." "LIQUEFYING OXYGEN WOULD TAKE ADDITIONAL STEPS." "ONE OF THE MORE IMPORTANT" "WAS THE INVENTION OF THE HEAT EXCHANGER." "THE HEAT EXCHANGER FEATURES TWO LONG TUBES, SIDE BY SIDE." "IT STARTS WORKING WHEN COLD FLUID ENTERS ONE END" "AND WARM FLUID ENTERS THE OTHER END" "OF THE SECOND TUBE." "AS THE WARM FLUID FLOWS," "IT MEETS THE COLD FLUID IN PASSING." "MOVING IN OPPOSITE DIRECTIONS, THE WARM FLUID COMES OUT" "AT NEARLY THE SAME TEMPERATURE" "AS THE COLD FLUID COMES IN." "THE REVERSE HAPPENS TO THE COLD FLUID," "WHICH COMES OUT HOT." "OBVIOUSLY THEN, THE FLUIDS HAVE EXCHANGED TEMPERATURES." "THIS COUNTERFLOW EXCHANGE OF HEAT," "SHOWN HERE BY ZIG-ZAGS," "IS THE HEART OF THE LIQUEFACTION PROCESS." "HEAT EXCHANGE NOW MAKES IT POSSIBLE" "TO LIQUEFY THOUSANDS OF LITERS OF OXYGEN AND NITROGEN" "ON A DAILY BASIS." "HISTORICALLY, IN THE QUEST FOR LOW TEMPERATURES," "WHILE THE HEAT EXCHANGER WAS A GREAT IDEA," "THE GOAL WOULDN'T BE REACHED" "WITHOUT ANOTHER DISCOVERY BY JAMES PRESCOTT JOULE." "FOR A WHILE, JOULE'S LUCK MIGHT HAVE BEEN BAD." "DESPITE HIS DISCOVERY" "OF THE LAW OF CONSERVATION OF ENERGY," "JOULE WASN'T SEEN AS A TOTALLY SERIOUS SCIENTIST." "BUT IN 1852, WILLIAM THOMSON, LORD KELVIN," "CONSIDERED JOULE THE MAN WHO'D CALCULATED" "THE MECHANICAL EQUIVALENT OF HEAT," "MEASURING TEMPERATURE IN HUNDREDTHS OF A DEGREE." "IN THAT VISION," "THOMSON SAW JOULE AS A WORTHY PARTNER" "IN THE EXCITING NEW FIELD OF THERMODYNAMICS." "UNITING AS CREATIVE FORCES" "ON THE DEVELOPING THEORY OF ENERGY CONSERVATION," "THEY WERE ABLE TO DISCOVER THE JOULE-THOMSON EFFECT." "WHEN A COMPRESSED GAS IS HEATED" "ABOVE ITS CRITICAL TEMPERATURE," "MOLECULES STILL ATTRACT EACH OTHER," "BUT THAT ATTRACTION ISN'T STRONG ENOUGH" "TO LIQUEFY THE GAS." "HOWEVER, EVEN THOUGH THERE'S NO LIQUID," "WHEN THE GAS EXPANDS THROUGH A HOLE OR NOZZLE," "THE PRINCIPLES OF EVAPORATION STILL OPERATE." "THE MOLECULES THAT ESCAPE" "ARE SLOWED DOWN AND COOLED IN THE PROCESS." "TODAY, WHAT JOULE AND THOMSON DISCOVERED" "IS BASICALLY THE FINAL STEP" "IN COOLING AND CONDENSING A COMPRESSED GAS INTO A LIQUID." "AT THE TIME, IT WOULD TAKE ANOTHER ENTERPRISING EUROPEAN" "TO TURN THE LIQUEFACTION OF GASES" "INTO A PRACTICAL BUSINESS." "HE WAS A VERY PRACTICAL GERMAN ENGINEER" "BY THE NAME OF CARL VON LINDE." "HIS PROCESS, WHICH USED ONLY AIR," "LAID THE GROUNDWORK FOR THE FUTURE." "IN DR. LINDE'S SYSTEM, COOLED COMPRESSED AIR" "PASSES THROUGH THE JOULE-THOMSON EXPANSION VALVE." "GAS THAT ISN'T LIQUEFIED IS RETURNED TO THE COMPRESSOR" "BY MEANS OF A HEAT EXCHANGER," "WHERE THE INCOMING COMPRESSED GAS" "IS COOLED TO A LOWER TEMPERATURE" "BY THE OUTGOING COLD GAS." "THE RESULT IS LIQUID AIR." "FROM A SCIENTIFIC POINT OF VIEW," "EVEN LIQUID AIR IS NOT THE END OF THE STORY." "WHEN LIQUID AIR," "THAT IS, LIQUID NITROGEN AND LIQUID OXYGEN," "WERE FIRST MADE," "IT WAS REALIZED THAT THE LIQUEFACTION OF HYDROGEN" "WOULD REQUIRE THE LOWEST TEMPERATURE OF ALL." "IT WAS ALSO REALIZED THAT WHOEVER LIQUEFIED HYDROGEN" "WOULD HAVE MADE A GREAT SCIENTIFIC TRIUMPH." "ONCE AGAIN, THE RACE WAS ON." "ONE STARTING POINT" "WAS THE SCIENTIFIC PLAYING FIELDS OF ENGLAND," "HOME OF THE ROYAL INSTITUTION," "WHICH POSSIBLY HAD AN EDGE TO BEGIN WITH." "THESE COOL BRITISH HALLS" "WERE THE INTELLECTUAL STOMPING GROUNDS" "OF FARADAY, CROOKES, AND DAVY." "SIR JAMES DEWAR EARNED HIS TITLE HERE." "HERE, TOO, LINGERED" "THE EXTREMELY COMPETITIVE GHOST OF ISAAC NEWTON." "ON ITS PICTURESQUE SURFACE," "THE NETHERLANDS HARDLY SEEMED AN ADVANTAGEOUS STARTING POINT." "BUT HOLLAND IS THE LAND OF THE UNIVERSITY OF LEIDEN." "NOT ONLY DID THESE WALLS" "ALREADY ECHO THE SCIENTIFIC LEGENDS" "OF MUSSCHENBRUEK, VAN MARUM, AND BOERHAAVE." "THIS WALL, PERHAPS THE MOST NOTEWORTHY GUEST REGISTER" "IN SCIENTIFIC HISTORY," "WOULD REFLECT WORLD-CLASS SCIENTIFIC ACHIEVEMENT" "FOR DECADES TO COME." "BUT IN THE 1880s," "LONG BEFORE LORENZ INVITED EINSTEIN TO LECTURE HERE," "THE RACE WAS STILL ON TO LIQUEFY HYDROGEN." "IN THE PHYSICAL LABORATORY OF THE UNIVERSITY OF LEIDEN," "WHEN IT CAME TO LIQUEFYING THE LAST REMAINING GAS KNOWN," "THE LEADING CANDIDATE" "WAS PROFESSOR HEIKE KAMERLINGH ONNES." "ACROSS THE ENGLISH CHANNEL, HOWEVER," "SMART LONDON BOOKMAKERS" "WERE PUTTING MONEY ON SIR JAMES DEWAR." "HE'D BECOME AN AUTHORITY ON GAS LIQUEFACTION." "ON ANY GIVEN FRIDAY," "HE'D BE ABLE TO STAND UP AND EXPLAIN PRECISELY WHY." "AT THE ROYAL INSTITUTION," "IN ADDITION TO INVENTIVE LECTURES," "DEWAR INVENTED MANY THINGS OF SCIENTIFIC NOTE," "INCLUDING A VARIETY OF DOUBLE-WALLED CONTAINERS" "TO KEEP FLUIDS COLD." "IN SCIENTIFIC CIRCLES, THESE HANDY LITTLE INVENTIONS" "BECAME KNOWN AS DEWAR FLASKS." "TODAY, THEY'RE MORE COMMONLY CALLED THERMOS JUGS." "IN ANY CASE, WITH THEIR HELP IN 1896," "JAMES DEWAR WON THE RACE." "HE WAS THE FIRST TO LIQUEFY HYDROGEN." "IN A STRANGE TWIST OF SCIENTIFIC HISTORY," "HE DIDN'T LIQUEFY THE LAST KNOWN GAS." "RIGHT AT WHAT WAS SUPPOSED TO BE THE FINISH LINE," "A NEW GAS WAS DISCOVERED" "HELIUM, WHICH WOULD HAVE" "THE LOWEST LIQUEFACTION POINT OF ALL." "FOR KAMERLINGH ONNES, HELIUM WAS ANOTHER OPPORTUNITY." "HE WANTED TO BE THE FIRST TO LIQUEFY" "THE LAST GAS ON EARTH." "IT TOOK EXTENSIVE SCHOLARSHIP AND EXTRAORDINARY MACHINERY." "IT TOOK CAPABLE ASSISTANTS AND OVER 10 YEARS," "BUT IT WAS A SUCCESS." "KAMERLINGH ONNES WAS THE FIRST TO LIQUEFY HELIUM" "AT A TEMPERATURE OF ONLY FOUR KELVIN DEGREES" "ABOVE THE ABSOLUTE ZERO." "HIS ACHIEVEMENT WAS NOT ONLY AMAZING FOR ITS TIME." "IT OPENED SCIENTIFIC FRONTIERS" "BEING EXPLORED TO THIS DAY." "LIQUID AIR IS NOT AS COLD AS LIQUID HELIUM." "IT'S STILL PLENTY COLD FOR MOST PURPOSES." "IT CAN CHANGE DRASTICALLY" "THE PROPERTIES OF ORDINARY MATTER." "TAKE THIS EXAMPLE." "I HAVE A LIGHT BULB NOW BEING LIT BY CURRENT" "THAT PASSES THROUGH THIS COPPER WIRE." "THE COPPER WIRE HAS HIGH ELECTRICAL RESISTANCE," "SO THE BULB IS BARELY GLOWING." "YOU CAN'T SEE IT, BUT I CAN." "IF I PUT THIS COPPER WIRE IN LIQUID AIR," "ITS ELECTRICAL RESISTANCE WILL DECREASE SO MUCH," "YOU'LL SEE THE BULB GLOW." "YOU CAN DO OTHER THINGS WITH LIQUID AIR." "PEOPLE TELL YOU TO PUT FLOWERS IN THE REFRIGERATOR." "THE EXTREME COLD OF LIQUID AIR REALLY ISN'T GOOD FOR FLOWERS." "IT DOESN'T CHANGE THE WAY THE FLOWERS LOOK." "THEY LOOK THE SAME." "THEY ARE A LITTLE BIT BRITTLE." "THERE IS ONE MORE THING" "I WILL TRY AT THIS TEMPERATURE," "AND THAT'S A FOOTBALL." "PEOPLE PLAY FOOTBALL GAMES" "IN CLIMATES LIKE GREEN BAY, WISCONSIN," "WHERE THE TEMPERATURE CAN BE 40 DEGREES BELOW ZERO." "I WORRY ABOUT THAT." "FOOTBALL PLAYERS GET PAID PLENTY FOR DOING THAT." "I DON'T WORRY ABOUT THE FANS" "BECAUSE ANYBODY AT A GAME IN THAT WEATHER" "DESERVES WHAT HE GETS." "I DON'T EVEN WORRY ABOUT THE SPORTSCASTERS." "THEY'RE INSIDE A WARM BROADCAST BOOTH," "WHERE THEY'RE PERFECTLY SAFE." "WHAT I REALLY WORRY ABOUT IS THE FOOTBALL ITSELF." "BECAUSE IT DOES SEEM TO ME THAT BEING THAT COLD" "CAN HAVE AN ABSOLUTELY SHATTERING IMPACT" "ON A FOOTBALL." "DON'T TAKE ANY WOODEN FOOTBALLS." "SEE YOU NEXT TIME." "CAPTIONING PERFORMED BY THE NATIONAL CAPTIONING INSTITUTE, INC." "CAPTIONS COPYRIGHT 1985 CALIFORNIA INSTITUTE OF TECHNOLOGY," "THE CORPORATION FOR COMMUNITY COLLEGE TELEVISION, AND THE ANNENBERG/CPB PROJECT" "Annenberg Media" "¶" "For information about this and other Annenberg Media programs call 1-800-LEARNER and visit us at"