Transcript for NASAWhy?Files - The Case of the Electrical Mystery

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HEY, YOU.

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HEY, ME?

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YEAH, YOU.

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COME SEE OUR CLUBHOUSE IN A TREE.

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WE ARE KIDS ON A MISSION TO EDUCATE
OURSELVES ABOUT THE NASA VISION.

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COME EXPLORE MATH AND SCIENCE
'CAUSE THAT'S WHAT MAKES

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OUR ALLIANCE.

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WE ARE THE "WHY?"

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FILES CLUB.

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WE YEARN TO LEARN AND WANT TO
SEE EVERYTHING THAT WE CAN BE.

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SO COME JOIN US ON OUR JOURNEY.

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DON'T YOU TOUCH THAT DIAL.

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AND WELCOME TO THE NASA "WHY?"

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FILES.

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HEY, THAT'S COOL.

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WHAT IS IT?

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IT'S THIS NEW GAME I BOUGHT.

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IT USES BATTERIES SO I
CAN PLAY IT AT THE POOL.

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YES, HIGH SCORE.

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CAN I PLAY?

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YEAH, HERE YOU GO.

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SO, YOU READY TO GO
TO MR. E'S POOL?

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AS SOON AS BIANCA GETS UP HERE.

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OH, IT'S STARTING TO RAIN.

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AND IT'S THUNDERING
AND LIGHTNING TOO.

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DOES THIS MEAN WE
CAN'T GO SWIMMING?

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I DON'T KNOW, IT DOESN'T LOOK GOOD.

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LET'S SEE IF KSNN IS REPORTING
ANYTHING ON THE STORM.

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I'M TED TUNE WITH THIS KID'S
SCIENCE NEWS NETWORK BULLETIN.

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THE NATIONAL WEATHER SERVICE
HAS ISSUED A SEVERE THUNDERSTORM

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WARNING FOR THE IMMEDIATE
LISTENING AREA.

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ANYONE OUTSIDE SHOULD TAKE SHELTER
IMMEDIATELY, AND NO ONE SHOULD GO

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TO THE POOL RIGHT NOW.

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THIS STORM IS CAPABLE
OF HEAVY RAIN,

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DANGEROUS LIGHTNING,
AND DAMAGING WINDS.

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WE HAVE A REPORT FROM OUR ON THE
SCENE REPORTER, I.M. LISSNING,

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WHO IS COMING TO US
LIVE FROM WATTSVILLE.

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TED, I'M ON THE WESTERN EDGE
OF TOWN, AND I CAN TELL YOU

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THAT THE STORM IS JUST ABOUT HERE.

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WE ARE EXPERIENCING HIGH
WINDS AND RAIN SHOWERS.

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FROM WHERE I'M STANDING, I
CAN SEE SPECTACULAR LIGHTNING.

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YEEOW!

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THAT ONE WAS CLOSE.

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OH, MY, THE POWER HAS GONE OUT.

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TED, IF YOU CAN SEE BEHIND ME,

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THE HOMES OF WATTSVILLE
HAVE ALL GONE DARK,

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VICTIMS OF THE STORM'S
TREMENDOUS ELECTRICAL SURGE.

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BACK TO YOU.

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WOW!

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THANKS, I.M., FOR
THAT SHOCKING REPORT.

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WE'LL BE BACK, SO STAY TUNED
TO KSNN FOR THE LATEST NEWS

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ON THE STORM, UNLESS, OF
COURSE, YOUR POWER IS OUT,

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AND THEN YOU CAN'T SEE OR HEAR ME.

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THE LIGHTS ARE FLICKERING
ON AND OFF.

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THE STORM'S RIGHT OVER US.

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MAYBE WE BETTER GET
OUT OF THE TREE HOUSE

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AND INTO OUR HOUSES,
WHERE IT'S SAFE.

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GOOD IDEA.

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SEE YOU LATER.

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OUR LIGHTS ARE WORKING AGAIN.

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I CAN'T WAIT TO GO
SWIMMING IN MR. E'S POOL.

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WELL, WE CAN'T.

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MR. E TELLS ME THAT
HIS POWER IS STILL

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OUT IN HIS HOUSE ACROSS THE STREET.

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IS THAT HIS HOUSE RIGHT OVER THERE?

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YES.

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HMM, I WONDER WHY POWER'S
ON IN OUR TREE HOUSE

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BUT OUT ACROSS THE STREET.

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WELL, WE ARE THE TREE
HOUSE DETECTIVES.

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WE'VE SOLVED A LOT
OF OTHER PROBLEMS,

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AND WE CAN SOLVE THIS ONE.

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WHAT PROBLEM?

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IT WAS JUST A LIGHTNING STORM.

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NOW, LET'S NOT JUMP TO CONCLUSIONS.

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WE NEED TO THINK ABOUT
THIS SCIENTIFICALLY.

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WHY DO WE HAVE TO USE THE
SCIENTIFIC METHOD EVERY TIME?

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BECAUSE IT WORKS.

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YOU KNOW, THOSE SCIENTIFIC
METHODS LIKE OBSERVATION --

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HYPOTHESIS, VARIABLES.

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YEAH, WE GOT IT.

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WELL, LISTEN, IF IT
DOESN'T WORK THIS TIME,

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THEN WE'LL NEVER USE IT AGAIN.

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LIKE THAT WILL EVER HAPPEN.

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YOU DO KNOW WHERE WE NEED TO
GO TO GET STARTED, DON'T YOU?

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THE PROBLEM BOARD.

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SO WHAT DO WE KNOW?

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WE KNOW THAT WE HAD A
LIGHTNING STORM LAST NIGHT.

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AND WE KNOW THE POWER
WAS ON BEFORE THE STORM.

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WE ALSO KNOW THAT THE POWER IS
STILL OFF ACROSS THE STREET.

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WE NEED TO KNOW IF LIGHTNING
CAN CAUSE A POWER OUTAGE.

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AND WE NEED TO KNOW WHAT
ELSE CAN CAUSE POWER OUTAGES.

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AND WE ALSO NEED TO KNOW WHY
WE HAVE POWER IN THE TREE HOUSE

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BUT NOT ACROSS THE STREET.

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I STILL THINK LIGHTNING
CAUSED THE POWER OUTAGE.

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OKAY, LET'S MAKE THAT
OUR HYPOTHESIS:

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LIGHTNING CAUSED THE POWER OUTAGE.

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BUT THAT STILL DOESN'T EXPLAIN WHY
WE HAVE POWER IN THE TREE HOUSE

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AND NOT ACROSS THE STREET.

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I'LL GO DO A WEB SEARCH ON
LIGHTNING AND SEE WHAT I CAN FIND.

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WHILE YOU'RE DOING THAT,
LET'S CHECK OUR HYPOTHESIS.

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HOW ARE WE GOING TO DO THAT?

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I DON'T KNOW.

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LET'S SEE IF DR. D WILL HELP US.

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HI, DR. D. HI.

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HI, GUYS.

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CAN YOU TELL US WHAT LIGHTNING IS?

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SURE.

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WAIT A MINUTE, WHAT BRINGS THIS UP?

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WELL, I WAS TELLING KALI AND
JACOB THAT THE POWER IS STILL

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OUT ACROSS THE STREET, BUT IT'S
STILL ON IN OUR TREE HOUSE.

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WE'RE TRYING TO FIGURE OUT WHY.

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WHERE ARE YOU GOING TO START?

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WE CAME UP WITH A HYPOTHESIS;

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WE THINK THAT LIGHTNING
CAUSED THE POWER OUTAGE.

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IT WAS A PRETTY BIG
STORM LAST NIGHT.

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HOW ARE YOU GOING TO
TEST YOUR HYPOTHESIS?

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WE'RE NOT SURE.

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WELL, TO UNDERSTAND LIGHTNING, WE
FIRST NEED TO LOOK AT SOME BASICS.

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LET'S RIP UP THIS PAPER.

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NOW COMB YOUR HAIR BRISKLY
AND THEN BRING THE COMB

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DOWN CLOSE TO THE PAPER.

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NEAT.

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WHY DID IT DO THAT?

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THE ANCIENT GREEKS
NOTICED THE SAME THING

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WHEN THEY RUBBED AMBER WITH WOOL.

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WHO'S AMBER?

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NOT "WHO," BUT "WHAT"?

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AMBER IS FOSSILIZED TREE SAP.

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OH, OKAY.

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THE AMBER PICKED UP LITTLE OBJECTS
LIKE STRANDS OF FIBER AND HAIR,

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JUST LIKE THE COMB
PICKED UP THE PAPER.

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WE SAY THAT THE COMB AND THE
AMBER ARE ELECTRICALLY CHARGED.

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CAN OTHER OBJECTS
DO THE SAME THING?

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SURE.

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THIS BALLOON CAN PICK
UP THE PAPER TOO.

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WOW.

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AND IT PICKS UP OTHER THINGS TOO,
LIKE THIS RICE CEREAL AND SALT.

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THE BALLOON WILL ALSO
STICK TO THE WALL.

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AND CAN ALSO DEFLECT
A STREAM OF WATER.

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WHOA.

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IF YOU RUB THE ACRYLIC
ROD WITH A PLASTIC BAG,

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IT'LL DO THE SAME THING.

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NOW, HOW DO YOU KNOW THAT
THE BALLOON WAS CHARGED

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AND NOT THE PAPER?

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WELL, IF AN OBJECT IS ELECTRICALLY
CHARGED, IT SHOULD PICK

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UP OBJECTS LIKE LITTLE PIECES
OF PAPER OR OTHER SUCH OBJECTS.

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LET'S SEE.

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NOTHING HAPPENED.

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VERY GOOD.

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A CHARGED OBJECT WILL PICK UP
OTHER NEUTRAL OR UNCHARGED OBJECTS,

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BUT AN UNCHARGED OBJECT WON'T.

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LET'S DO AN EXPERIMENT
WITH SOME TAPE.

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BRING THIS BAR AROUND.

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PUT SOME TAPE ON THE TABLE.

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NOW PULL IT UP REAL QUICKLY.

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AND WATCH THIS.

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IT ATTRACTED THE PAPER.

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IT MUST BE CHARGED.

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NOW LET'S TRY TWO PIECES OF
TAPE, ONE ON TOP OF EACH OTHER.

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HOLD ON TO THAT, PLEASE.

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HOW CAN WE TELL IF
THESE ARE CHARGED?

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WE NEED TO DO THE PAPER
SCRAPS TEST TO FIND OUT.

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LET'S TRY IT.

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YEP, THEY'RE CHARGED, ALL RIGHT.

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WELL, HERE'S THE EXPERIMENT:

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LET'S HANG UP THIS SINGLE
PIECE OF CHARGED TAPE.

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NOW WE'LL PULL UP THE DOUBLE TAPE.

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FIRST THE TOP PIECE.

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IT ATTRACTS THE TAPE,
JUST LIKE BEFORE.

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IT'S REPELLING THE SECOND TAPE.

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WE HAVEN'T SEEN THAT BEFORE.

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WHAT CONCLUSIONS CAN YOU MAKE?

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WELL, IF THE OBJECT IS CHARGED,
IT ATTRACTS UNCHARGED ITEMS,

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BUT IT MAY ATTRACT OR
REPEL OTHER CHARGED ITEMS.

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DOES THAT MEAN THERE ARE
TWO TYPES OF CHARGES?

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THAT'S RIGHT, THE TWO TYPES OF
CHARGES ARE POSITIVE AND NEGATIVE.

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THE TOP AND THE BOTTOM
PIECE HAD DIFFERENT CHARGES.

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NOW LET'S DO THIS AGAIN.

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THIS TIME, WE'LL TAKE BOTH PIECES
OF TAPE IN EXACTLY THE SAME WAY,

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SO -- THEY MUST HAVE
THE SAME CHARGE.

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THAT'S RIGHT.

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WILL THEY ATTRACT OR REPEL?

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THEY REPEL.

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LET'S SEE, IF THE CHARGES ARE
DIFFERENT, THEN THEY MUST ATTRACT.

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LET'S FIND OUT.

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ALL RIGHT, WE USE
THE TWO TAPES AGAIN.

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BOTH HAVE DIFFERENT CHARGES.

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HOW ABOUT THAT?

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LOOK AT THIS MACHINE, IT'S
CALLED A VAN DE GRAAFF GENERATOR.

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JACOB, STAND UP ON THIS
STOOL, IF YOU WOULD,

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AND PUT YOUR HANDS ON TOP.

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I'M GOING TO TURN THIS MACHINE ON

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AND TRANSFER A LOT
OF CHARGE INTO YOU.

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IT WON'T SHOCK YOU, I PROMISE.

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WOW, HIS HAIR IS REALLY
STANDING UP.

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IS IT BECAUSE ALL MY HAIR
IS CHARGED THE SAME WAY

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AND EACH STRAND IS
REPELLING OR PUSHING AWAY

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FROM THE STRAND NEXT TO IT?

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THAT'S RIGHT, IN THE BEGINNING
YOUR BODY WAS NEUTRAL,

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IT HAD THE SAME NUMBER OF
POSITIVE AND NEGATIVE CHARGES.

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WE CALL POSITIVE CHARGES PROTONS,
AND NEGATIVE CHARGES ELECTRONS.

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WE TRANSFERRED AN AWFUL LOT

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OF NEGATIVELY CHARGED
ELECTRONS INTO YOUR BODY.

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WHAT KIND OF CHARGE
WOULD YOU HAVE THEN?

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WELL, IF THE NUMBER OF
ELECTRONS AND PROTONS

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IN HIS BODY WERE THE SAME,

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THEN THEY WOULD BASICALLY
CANCEL EACH OTHER OUT.

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AND THEN IF WE ADDED
A LOT OF ELECTRONS,

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THEN I GUESS HIS BODY WOULD
BE NEGATIVELY CHARGED.

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THAT'S RIGHT.

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AND I ALWAYS THOUGHT YOU
WERE THE NEGATIVE ONE.

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NOW, IF WE TURN THE THING ON AGAIN,
BUILD UP A HUGE CHARGE ON TOP --

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MOVE THE SECOND BALL
CLOSER TO THE FIRST --

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WOW, IT LOOKS JUST LIKE LIGHTNING.

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NOW, WHAT'S GOING ON THERE?

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WELL, THE ELECTRONS ARE JUMPING
FROM THE VAN DE GRAAFF TO THE BALL.

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IT LOOKS MORE LIKE A FLASH OF
LIGHT THAN A BUNCH OF PARTICLES.

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WELL, I LEARNED THAT
YOU CAN'T SEE ELECTRONS.

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SO, HOW CAN WE SEE THESE ELECTRONS?

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WELL, YOU'RE RIGHT, ELECTRONS
ARE TOO SMALL TO SEE,

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BUT AS THE ELECTRONS JUMP FROM
THE VAN DE GRAAFF TO THE BALL,

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THEY HEAT UP THE AIR
AND CAUSE IT TO GLOW.

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WHAT YOU'RE SEEING IS THE GLOWING
AIR, NOT THE MOVING ELECTRONS.

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IS THIS HOW LIGHTNING WORKS?

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YES, IT'S VERY SIMILAR.

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SO, DR. D, DO WE GET
ELECTRICITY FROM LIGHTNING?

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NOT QUITE.

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I TELL YOU WHAT, I'M GOING TO
LINE YOU UP WITH A RESEARCHER

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FROM NASA LANGLEY RESEARCH
CENTER IN HAMPTON, VIRGINIA.

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HIS NAME IS BRUCE FISHER.

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HE'S DONE A LOT OF
STUDIES ON LIGHTNING.

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I'LL ARRANGE FOR YOU TO MEET HIM AT
THE VIRGINIA AIR AND SPACE CENTER.

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GREAT, THANKS, DR. D.
SO, LET'S GET UP AND GO.

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BYE, DR. D. BYE, GUYS.

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BYE.

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HI, MR. FISHER.

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DR. D SAID THAT YOU
HAVE STUDIED LIGHTNING

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AND COULD EXPLAIN IT TO US.

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SURE, I WORKED FOR SEVERAL YEARS ON
A RESEARCH PROGRAM AT NASA LANGLEY

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WHERE WE STUDIED THE EFFECTS
OF LIGHTNING ON AIRPLANES.

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WHAT IS LIGHTNING
AND HOW DOES IT WORK?

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DO YOU UNDERSTAND ABOUT
POSITIVE AND NEGATIVE CHARGES?

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YES.

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AS A THUNDERSTORM BUILDS AND
MATURES, THE CHARGES TEND

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TO SEPARATE INSIDE THE STORM.

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TYPICALLY, THE POSITIVE CHARGES
GO TOWARDS THE TOP OF THE STORM,

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AND THE NEGATIVE CHARGES GO
TOWARDS THE BOTTOM OF THE STORM.

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NOW, WHAT'S IMPORTANT TO REMEMBER

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ABOUT POSITIVE AND
NEGATIVE CHARGES?

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I KNOW THAT OPPOSITE CHARGES
ATTRACT AND LIKE CHARGES REPEL.

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EXACTLY.

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AND WHAT HAPPENS AS
A STORM MATURES,

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YOU START TO GET AN ATTRACTION
BETWEEN THE NEGATIVE CHARGES

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AT THE BOTTOM OF THE CLOUD AND THE
POSITIVE CHARGES ON THE GROUND.

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AND EVENTUALLY, YOU'LL GET
THOSE TWO CHARGES TO MEET.

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WHEN THEY DO, THERE'S A CHANNEL
BETWEEN THEM, THE POSITIVE

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AND THE NEGATIVE -- THAT'S
WHAT WE CALL A LIGHTNING BOLT,

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AND THAT IS A CLOUD-TO-GROUND
LIGHTNING DISCHARGE.

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WHY DOESN'T THE NEGATIVE

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AND POSITIVE CHARGES ATTRACT
EACH OTHER IN THE CLOUD?

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THEY CAN; IN FACT, 70 PERCENT
OF ALL LIGHTNING WHICH OCCURS

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IN NATURE DOES OCCUR
UP IN THE CLOUDS,

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WHAT WE CALL CLOUD-TO-CLOUD
LIGHTNING.

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DOES LIGHTNING EVER HIT THE PLANES?

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ABSOLUTELY.

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IN FACT, LET ME SHOW YOU
SOMETHING HERE IN THE MUSEUM.

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WALK OVER THIS WAY.

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NOW, SEE THE AIRPLANE OVER THERE?

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THAT'S AN F-106B DELTA DART, WHICH
IS A TWO-SEAT FIGHTER AIRCRAFT.

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AND IT WAS USED BY NASA LANGLEY,
WHERE I WORK, FOR FIVE OR SIX YEARS

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TO FLY THROUGH THUNDERSTORMS
TO INTENTIONALLY LOOK

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FOR LIGHTNING STRIKES TO AIRCRAFT.

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THE AIRPLANE'S BEEN STRUCK
ABOUT 700 TIMES BY LIGHTNING.

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DURING THAT TIME, I SAT IN
THE BACK SEAT OF THE AIRCRAFT,

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AND I WAS STRUCK BY LIGHTNING
ABOUT 256 TIMES DURING ALL

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OF OUR RESEARCH FLIGHTS.

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THERE'S NO WAY I'D GO UP IN A
PLANE DURING A LIGHTNING STORM.

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WHAT'S IT LIKE TO FLY A
PLANE THROUGH A STORM?

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THE GREATEST WORRIES
THAT YOU HAVE WHEN FLYING

[00:12:41.490]
THROUGH A THUNDERSTORM
IS NOT THE LIGHTNING.

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WE WERE LOOKING FOR THE LIGHTNING,

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AND THE AIRPLANE WAS
READY FOR THAT.

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WHAT WE WERE FRIGHTENED
OF WAS THE TURBULENCE.

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IT'S A VERY ROUGH RIDE
INSIDE OF THUNDERSTORMS.

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THIS IS A VERY ROUGH-RIDING
AIRCRAFT, SO YOU GET BOUNCED AROUND

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AND JIGGLED AROUND A LOT INSIDE
THE COCKPIT OF THE AIRCRAFT.

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IT'S A VERY ROUGH RIDE.

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THE LIGHTNING WAS THE FUN PART.

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YOU COULD SEE THE LIGHTNING
BOOM, THE LIGHTNING FLASH.

[00:13:02.500]
IT'D HIT THE NOSE
BOOM OF THE AIRCRAFT,

[00:13:04.170]
YOU'D SEE THE LIGHTNING
CHANNEL CAUSE SPARKS

[00:13:06.500]
WHERE THERE'S MELTING METAL
ON THE FRONT OF THE AIRPLANE.

[00:13:08.920]
YOU'D SEE THE LIGHTNING
CHANNEL FLICKER.

[00:13:10.810]
SOMETIMES YOU'D HEAR IT RUMBLE
IF IT WAS A BIG ENOUGH FLASH.

[00:13:14.130]
YOU'D SEE IT SWEEP FROM THE
FRONT OF THE AIRPLANE TO THE BACK

[00:13:16.350]
OF THE AIRPLANE -- A REAL LIGHT
SHOW, AS IF IT WAS IN SLOW MOTION.

[00:13:19.920]
ONLY LASTS ABOUT ONE SECOND,
BUT IT SEEMS IT TAKES FOREVER

[00:13:22.470]
WHEN YOU SEE IT HIT THE AIRCRAFT.

[00:13:23.830]
AND ALL YOU WOULD TYPICALLY HEAR,
BECAUSE WE'RE WEARING HEADSETS,

[00:13:27.030]
WOULD BE JUST A SNAP IN YOUR EAR,

[00:13:28.920]
JUST A SNAP WHEN THE
LIGHTNING WOULD STRIKE,

[00:13:31.090]
BUT A LOT OF THE LIGHTNING
FLASHES, LIGHTNING STRIKES,

[00:13:33.190]
WE NEVER SAW, BECAUSE THEY ALL
HIT BACK UP IN THE REAR END

[00:13:36.130]
OF THE AIRPLANE, FROM WINGTIP
TO WINGTIP OR AROUND THE EXHAUST

[00:13:39.040]
OF THE ENGINE, SO WE'D HAVE TO
COME BACK AFTWERARDS AND LOOK

[00:13:42.100]
AT VIDEOTAPES WITH
THE PILOTS AND FIGURE

[00:13:44.560]
OUT WHERE THE LIGHTNING
STRIKES HIT US

[00:13:46.100]
AND WHEN THE LIGHTNING STRIKES
HIT US, BECAUSE MOST OF THEM,

[00:13:49.290]
WE NEVER KNEW WE'D BEEN HIT.

[00:13:50.660]
YOU MIGHT JUST HEAR A SNAP.

[00:13:52.110]
YOU MIGHT LOSE THAT SNAP IN ALL
THE OTHER NOISES THAT ARE GOING

[00:13:54.650]
ON INSIDE THE COCKPIT
OF THE AIRPLANE.

[00:13:57.370]
ALL THE RESEARCH THAT
WE DID IS BEING USED

[00:13:59.890]
TO MAKE COMMERCIAL AIRCRAFT SAFER,
TO MAKE FIGHTER AIRCRAFT SAFER,

[00:14:04.230]
AND IT'S EVEN BEING USED
TO MAKE THE LAUNCHES

[00:14:07.090]
OF THE SPACE SHUTTLE SAFER SO
THAT THEY DON'T GET INVOLVED

[00:14:09.660]
WITH LIGHTNING WHEN THEY'RE
TRYING TO GO INTO ORBIT

[00:14:11.310]
FROM THE KENNEDY SPACE CENTER.

[00:14:13.470]
WOW.

[00:14:14.300]
DOES ELECTRICITY COME
FROM LIGHTNING?

[00:14:16.530]
LIGHTNING IS AN ELECTRICAL
SPARK, BUT POWER, ELECTRICITY,

[00:14:20.200]
AND LIGHTNING ARE NOT
QUITE THE SAME THING.

[00:14:22.020]
CAN LIGHTNING CAUSE
THE POWER TO GO OUT?

[00:14:24.850]
LIGHTNING CAN CAUSE ALL SORTS
OF UNPLEASANT THINGS TO HAPPEN,

[00:14:27.510]
INCLUDING POWER OUTAGES, BUT I'M
NOT AN EXPERT IN POWER GENERATION,

[00:14:30.960]
I'M AN AEROSPACE ENGINEER.

[00:14:32.810]
WHAT YOU SHOULD DO IS SEND AN
EMAIL TO YOUR LOCAL POWER COMPANY

[00:14:35.380]
AND SEE WHAT THEY CAN TELL
YOU ABOUT POWER OUTAGES

[00:14:37.310]
AND POWER DISTURBANCES
FROM LIGHTNING.

[00:14:39.390]
OK, THANKS FOR YOUR
HELP, MR. FISHER.

[00:14:41.270]
YOU'RE WELCOME.

[00:14:41.850]
BYE.

[00:14:41.920]
HAVE A GOOD DAY.

[00:14:44.260]
I'M RUBBING THIS BALLOON ON
MY ARM TO GIVE IT CHARGE.

[00:14:51.460]
OK, THAT OUGHT TO BE ENOUGH.

[00:14:53.330]
NOW LET'S SEE IF WE
CAN MOVE THIS CAN.

[00:14:55.330]
WOW, PRETTY NEAT.

[00:14:57.890]
YOU CAN SEE HOW TO DO THIS
EXPERIMENT AND OTHER EXPERIMENTS

[00:15:00.770]
ON STATIC ELECTRICITY
AT THE NASA "WHY?"

[00:15:03.170]
FILES WEBSITE AT:
WHYFILES.LARC.NASA.GOV.

[00:15:06.960]
NOW THAT WE'VE LEARNED ABOUT
STATIC ELECTRICITY AND LIGHTNING,

[00:15:12.090]
LET'S GO BACK TO OUR BOARD.

[00:15:13.860]
WHAT DO WE KNOW?

[00:15:14.820]
WE KNOW THAT LIGHTNING
ISN'T THE SAME

[00:15:17.230]
AS THE ELECTRICITY
WE USE IN OUR HOME.

[00:15:19.640]
WE'VE LEARNED ABOUT POSITIVE
AND NEGATIVE CHARGESS

[00:15:21.820]
AND ABOUT HOW OPPOSITE CHARGES
ATTRACT AND LIKE CHARGES REPEL.

[00:15:25.570]
WHAT ELSE DO WE KNOW?

[00:15:26.780]
REMEMBER THE E-MAIL THAT I
SENT TO THE POWER COMPANY?

[00:15:29.560]
WELL, THE RESPONSE SAYS

[00:15:31.240]
THAT LIGHTNING CAN CAUSE AN
OUTAGE EITHER AT THE POWER SOURCE

[00:15:33.630]
OR SOMEWHERE BETWEEN THE
POWER SOURCE AND OUR HOME.

[00:15:36.980]
HMM, SO MAYBE WE SHOULD
CHANGE OUR HYPOTHESIS TO:

[00:15:39.560]
LIGHTNING HIT THE POWER SOURCE.

[00:15:41.540]
BUT WHAT IS A POWER SOURCE?

[00:15:43.330]
ISN'T IT THE PLACE WHERE
THEY MAKE THE POWER,

[00:15:45.810]
YOU KNOW WHERE THE
POWER COMES FROM?

[00:15:47.880]
LIKE A BUNCH OF BIG BATTERIES?

[00:15:49.450]
I SUPPOSE WHAT WE NEED TO KNOW
IS WHAT A POWER SOURCE IS,

[00:15:53.090]
AND HOW POWER GETS TO OUR HOMES.

[00:15:55.370]
I GUESS THAT'S THE NEXT
PART OF OUR INVESTIGATION.

[00:15:59.220]
SO HOW'S YOUR RESEARCH
COMING ALONG?

[00:16:01.010]
FINE.

[00:16:02.080]
WE CHANGED OUR HYPOTHESIS.

[00:16:03.600]
YOU HAVE TO REVISE YOUR
HYPOTHESIS SOMETIMES.

[00:16:05.810]
IT'S PART OF THE SCIENTIFIC
PROCESS.

[00:16:07.250]
HOW DOES IT READ NOW?

[00:16:08.470]
WE SAID THAT "LIGHTNING
HIT THE POWER SOURCE."

[00:16:10.340]
I SEE.

[00:16:11.200]
YOUR TRAIN SET IS REALLY NEAT.

[00:16:12.590]
WELL, THANK YOU.

[00:16:13.150]
BEEN WORKING ON IT A LONG TIME.

[00:16:14.920]
JUST PUTTING THE FINISHING
TOUCHES ON IT.

[00:16:16.680]
CAN YOU TURN IT ON, DR. D?

[00:16:17.760]
SURE.

[00:16:19.250]
[00:16:20.710]
THAT'S FUNNY.

[00:16:21.250]
IT WAS WORKING BEFORE.

[00:16:22.760]
WELL, IS THE TRAIN PLUGGED IN?

[00:16:24.000]
LET ME CHECK.

[00:16:25.870]
YEAH, IT'S STILL PLUGGED IN.

[00:16:27.260]
I'M REALLY STUMPED.

[00:16:30.070]
SO WHAT'S UP?

[00:16:31.000]
CAN YOU THINK OF SOME REASONS WHY
DR. D'S TRAIN SET DOESN'T WORK?

[00:16:35.050]
WHY IS POWER OUT ON ONE SIDE OF
THE STREET AND NOT THE OTHER?

[00:16:38.560]
DO YOU THINK THAT LIGHTNING
CAUSED THE POWER OUTAGE?

[00:16:40.730]
HOW CAN THE TREE HOUSE
DETECTIVES USE SCIENTIFIC METHODS

[00:16:44.180]
TO SOLVE THE PROBLEM?

[00:16:45.990]
STAY TUNED.

[00:16:46.870]
WE'LL HAVE MORE NEXT TIME.

[00:16:53.400]
SO DR. D, P.J. TELLS US THAT
YOUR TRAIN SET'S PRETTY COOL

[00:16:58.400]
AND THAT YOU WERE
HAVING PROBLEMS WITH IT.

[00:17:00.100]
HAVE YOU FIGURED OUT
WHAT'S WRONG YET?

[00:17:01.750]
NOT YET, BUT I BET IF WE WORK
TOGETHER AS A GROUP AND CHECK

[00:17:04.680]
OUT THE VARIABLES ONE AT A
TIME, WE'LL FIND THE PROBLEM.

[00:17:07.050]
OK.

[00:17:08.170]
WHAT'S A VARIABLE?

[00:17:09.180]
A VARIABLE IS ONE SPECIFIC
THING THAT CAN AFFECT

[00:17:11.720]
OR CHANGE THE END
RESULT OR THE ANSWER.

[00:17:13.530]
I'VE GOT AN IDEA; I BET
IT'S THE WALL OUTLET.

[00:17:17.270]
IF THERE'S NO ELECTRICITY
THERE, NOTHING ELSE WILL WORK.

[00:17:20.280]
LET'S MAKE THAT OUR FIRST VARIABLE.

[00:17:22.170]
HOW CAN WE CHECK OUT
THE WALL OUTLET?

[00:17:24.200]
WE CAN PLUG IN SOMETHING
THAT WE KNOW WORKS.

[00:17:26.540]
EXACTLY RIGHT.

[00:17:27.220]
I'VE GOT A PLASMA BALL WE CAN USE.

[00:17:29.760]
LET'S TURN THE LIGHTS DOWN A
LITTLE SO WE CAN SEE IT BETTER.

[00:17:31.960]
AND WE'LL PLUG IT IN THERE
TO MAKE SURE IT'S WORKING.

[00:17:37.000]
COOL.

[00:17:38.510]
NOW LET'S PLUG IT INTO THE
SAME OUTLET THE TRAIN SET USES.

[00:17:41.170]
IT WORKS FINE.

[00:17:44.080]
I GUESS WE'VE ELIMINATED
ONE POSSIBLE VARIABLE.

[00:17:47.140]
I'LL CHECK A COUPLE
OF OTHER THINGS LATER.

[00:17:49.260]
BY THE WAY, HOW ARE
YOU COMING ALONG

[00:17:50.440]
WITH YOUR ELECTRICITY MYSTERY?

[00:17:52.200]
WELL, WE STILL THINK LIGHTNING
CAUSED THE POWER OUTAGE

[00:17:54.820]
ACROSS THE STREET
FROM THE TREE HOUSE.

[00:17:56.940]
WE KNOW THAT LIGHTNING
DOESN'T CAUSE ELECTRICITY,

[00:17:59.560]
BUT WE'RE STILL NOT SURE
WHERE IT COMES FROM.

[00:18:02.320]
CAN YOU TELL US?

[00:18:03.940]
WELL, ELECTRICITY IS
ELECTRIC CHARGES FLOWING

[00:18:05.940]
THROUGH THE WIRES OF A CIRCUIT.

[00:18:07.400]
IN A STANDARD CIRCUIT,
THE CHARGES ARE ELECTRONS.

[00:18:09.940]
THERE ARE SEVERAL WAYS TO
FORCE THE CHARGES TO FLOW.

[00:18:12.190]
DO YOU KNOW WHAT SOME OF THEM ARE?

[00:18:13.780]
DON'T BATTERIES PRODUCE
ELECTRICITY?

[00:18:16.490]
THAT'S RIGHT.

[00:18:17.430]
IN FACT, WE CAN MAKE OUR
OWN BATTERY OUT OF LEMONS

[00:18:19.790]
OR OTHER PIECES OF FRUIT.

[00:18:21.050]
A BATTERY FROM FRUIT?

[00:18:24.000]
SURE.

[00:18:24.370]
A FLASHLIGHT OR THE BATTERY IN YOUR
PARENTS' CAR ISN'T MADE OF LEMONS,

[00:18:28.110]
BUT IT WORKS USING
THE SAME PRINCIPLES.

[00:18:29.700]
CAN YOU USE A LEMON
TO POWER SOMETHING?

[00:18:32.460]
LET'S SEE.

[00:18:33.390]
I'VE GOT A LITTLE L.C.D. CLOCK.

[00:18:35.090]
IT NORMALLY WORKS WITH A WATCH
BATTERY, ABOUT 1 1/2 VOLTS.

[00:18:38.530]
HOOK TOGETHER SOME LEMONS LIKE
THIS, AND LET'S SEE WHAT HAPPENS.

[00:18:41.440]
IT'S WORKING.

[00:18:41.770]
THAT'S AMAZING.

[00:18:44.080]
CAN YOU THINK OF ANOTHER
WAY TO CREATE ELECTRICITY?

[00:18:47.780]
HOW ABOUT SOLAR POWER?

[00:18:49.200]
THAT'S CALLED A SOLAR
CELL, ISN'T IT?

[00:18:51.050]
I SAW ON TV THAT NASA USES
SOLAR CELLS TO POWER SATELLITES

[00:18:54.020]
AND EVEN INTERNATIONAL
SPACE STATIONS.

[00:18:55.930]
THAT'S RIGHT.

[00:18:56.360]
LOOK AT THIS SOLAR-POWERED
BICYCLIST, HERE.

[00:18:59.390]
THE BRIGHTER THE LIGHT,
THE FASTER HE PEDALS.

[00:19:04.050]
[00:19:05.790]
SO DO YOU KNOW HOW SOLAR CELLS

[00:19:08.400]
AND BATTERIES CAUSE
THE CHARGES TO FLOW?

[00:19:10.820]
WHAT DO YOU MEAN?

[00:19:11.900]
ELECTRICITY DOESN'T
APPEAR OUT OF NOWHERE.

[00:19:14.300]
A VERY IMPORTANT LAW
OF PHYSICS SAYS,

[00:19:16.110]
"YOU CAN'T GET SOMETHING
FOR NOTHING."

[00:19:18.320]
IT TAKES WORK TO PUSH THE
CHARGES THROUGH THE WIRES.

[00:19:21.210]
AND THE ENERGY TO DO THAT
MUST COME FROM SOMEPLACE.

[00:19:24.400]
A SOLAR CELL USES THE
ENERGY OF THE SUN.

[00:19:26.990]
BATTERIES USE CHEMICAL ENERGY.

[00:19:28.420]
WHAT OTHER KINDS OF SOURCES
OF ELECTRICITY ARE THERE?

[00:19:31.030]
A POWER COMPANY IS A
SOURCE OF ELECTRICITY.

[00:19:33.590]
IT'S EASY TO PLUG INTO
OUTLETS AND GET POWER,

[00:19:36.310]
BUT I GUESS I DON'T KNOW
HOW THEY PRODUCE IT.

[00:19:38.560]
DO THEY USE A BATTERY?

[00:19:39.940]
THAT'S A GOOD GUESS.

[00:19:41.530]
POWER COMPANY USES
MECHANICAL MOTION, HOWEVER,

[00:19:43.860]
TO CREATE ELECTRICITY.

[00:19:45.130]
LET ME ILLUSTRATE.

[00:19:46.560]
TURN THIS CRANK AND
TELL ME WHAT HAPPENS.

[00:19:55.560]
[00:19:57.230]
THE FASTER I TURN THE HANDLE,
THE BRIGHTER THE LIGHTBULB GLOWS.

[00:20:00.050]
THAT'S RIGHT.

[00:20:00.800]
WHEN YOU TURN THE HANDLE,
YOU'RE PROVIDING ENERGY

[00:20:03.600]
TO FORCE THE ELECTRONS
TO MOVE THROUGH THE WIRE.

[00:20:05.500]
THE MOTION THAT CHARGES THROUGH
THE WIRE IS CALLED THE CURRENT.

[00:20:08.370]
NOW THIS TIME, TURN THE
CRANK, KEEP YOUR EYES CLOSED,

[00:20:11.340]
AND TELL ME WHEN SOMETHING HAPPENS.

[00:20:12.570]
WOW, IT'S A LOT EASIER TO TURN NOW.

[00:20:19.270]
WHAT HAPPENED?

[00:20:20.300]
I UNSCREWED THE LIGHTBULB.

[00:20:21.590]
IT ONLY TAKES WORK TO
TURN THE CRANK AS LONG

[00:20:23.760]
AS YOU'RE LIGHTING THE BULB.

[00:20:24.960]
WE WERE ONLY LIGHTING ONE BULB.

[00:20:26.970]
LET'S ADD SOME MORE BULBS, SEE
IF IT'S HARDER TO TURN THE CRANK.

[00:20:29.220]
ALL RIGHT, GO AHEAD.

[00:20:31.370]
WHOA, IT'S A LOT HARDER NOW.

[00:20:33.140]
I'M REALLY HAVING TO WORK AT THIS.

[00:20:40.040]
BUT DR. D, OBVIOUSLY PEOPLE DON'T
TURN THE CRANKS IN THE POWER PLANT.

[00:20:43.180]
WHAT OTHER SOURCES OF
ENERGY COULD YOU USE,

[00:20:45.480]
OTHER THAN PEOPLE,
TO TURN THE CRANK?

[00:20:47.220]
WE CAN USE WIND POWER
TO TURN THE CRANK.

[00:20:49.640]
WIND POWER IS USED TO
CREATE ELECTRICITY,

[00:20:51.890]
BUT IT'S NOT OFTEN USED FOR
LARGE-SCALE POWER PRODUCTION.

[00:20:54.610]
I THINK THE POWER PLANT IN
OUR TOWN USES NATURAL GAS.

[00:20:57.800]
THAT'S RIGHT, POWER PLANTS
USE COAL, OIL, NATURAL GAS,

[00:21:01.240]
AND EVEN NUCLEAR FISSION
TO PROVIDE THE ENERGY

[00:21:03.360]
TO CREATE ELECTRICITY.

[00:21:04.240]
IN EACH OF THESE CASES THE
BURNING OF COAL, OIL, NATURAL GAS,

[00:21:09.270]
AND THE FISSION OF URANIUM
PROVIDES THE HEAT TO PRODUCE STEAM.

[00:21:12.620]
THE STEAM CAUSES A TURBINE TO
SPIN, WHICH TURNS THE CRANK

[00:21:16.150]
IN THE GENERATOR,
PRODUCING THE ELECTRICITY.

[00:21:18.160]
IT'S JUST LIKE OUR
EXPERIMENT, BUT WITH MORE POWER.

[00:21:20.830]
THERE'S ANOTHER NATURAL PROCESS
THAT CAN BE USED TO PROVIDE ENERGY

[00:21:23.960]
TO CREATE ELECTRICITY.

[00:21:24.730]
DO YOU KNOW WHAT IT IS?

[00:21:25.760]
HMM, ISN'T IT FLOWING WATER?

[00:21:28.300]
THAT'S RIGHT.

[00:21:29.020]
WHEN WATER FLOWS DOWNHILL, IT HAS
THE ENERGY TO TURN THE TURBINE.

[00:21:32.220]
THE MOST INTERESTING POWER PROJECT

[00:21:33.730]
IN THE UNITED STATES
IS AT NIAGARA FALLS.

[00:21:35.840]
WHY DON'T YOU CHECK IT OUT?

[00:21:39.620]
OK, I'LL E-MAIL THEM
AND SEE IF WE CAN TALK

[00:21:43.590]
TO THEM ABOUT THEIR FACILITY.

[00:21:44.210]
HI, I'M JOANNE WILMOTT, THE NEW
YORK POWER AUTHORITY'S REGIONAL

[00:21:49.580]
MANAGER FOR COMMUNITY RELATIONS
HERE IN WESTERN NEW YORK.

[00:21:53.410]
WE GOT YOUR E-MAIL AND
UNDERSTAND YOU'D LIKE TO LEARN MORE

[00:21:56.430]
ABOUT THE NIAGARA POWER
PROJECT AND HOW IT WORKS.

[00:21:59.420]
LET ME SHOW YOU AROUND.

[00:22:01.230]
BEFORE WE GET STARTED, DO YOU KNOW
ANYTHING ABOUT THE NIAGARA PROJECT?

[00:22:04.980]
I KNOW THAT IT SITS ON THE NIAGARA
RIVER BETWEEN NEW YORK AND ONTARIO.

[00:22:09.170]
THAT'S RIGHT.

[00:22:10.100]
THE NIAGARA POWER PROJECT
IS THE RESULT OF COOPERATION

[00:22:13.910]
BETWEEN THE UNITED
STATES AND CANADA.

[00:22:16.810]
AS A MATTER OF FACT, THE CANADIAN
POWER PLANTS ARE LOCATED DIRECTLY

[00:22:21.150]
ACROSS THE RIVER FROM OURS.

[00:22:23.390]
BOTH THE UNITED STATES AND
CANADA HAVE SHARED THE WATERS

[00:22:26.750]
OF THE NIAGARA RIVER
FOR MANY YEARS,

[00:22:29.310]
AND BOTH COUNTRIES
ARE FIRMLY COMMITTED

[00:22:31.620]
TO PRESERVING THE
BEAUTY OF NIAGARA FALLS.

[00:22:34.880]
NIAGARA FALLS IS REALLY BEAUTIFUL.

[00:22:36.930]
I VISITED ONCE ON SUMMER VACATION.

[00:22:39.140]
IT SURE IS.

[00:22:39.640]
AND DID YOU KNOW THAT WHEN THE
NIAGARA PROJECT PRODUCED ITS FIRST

[00:22:43.770]
POWER BACK IN 1961, IT WAS THE
LARGEST HYDROELECTRIC POWER PLANT

[00:22:48.990]
IN THE WESTERN WORLD AT THAT TIME?

[00:22:51.720]
TODAY IT'S STILL NEW YORK STATE'S
LARGEST ELECTRICITY GENERATOR,

[00:22:55.900]
AND HERE WE HAVE THE CAPABILITY

[00:22:57.670]
TO GENERATE 2,400,000
KILOWATTS OF ELECTRICITY.

[00:23:02.900]
THAT'S ENOUGH TO LIGHT 24
MILLION 100-WATT LIGHT BULBS

[00:23:07.230]
AT ANY ONE TIME.

[00:23:09.260]
THE LOW-COST POWER GENERATED
HERE ALSO SAVES NEW YORK STATE'S

[00:23:13.160]
BUSINESSES AND RESIDENTS
MILLIONS OF DOLLARS ANNUALLY.

[00:23:17.640]
HOW IS ELECTRICITY MADE?

[00:23:19.370]
HERE'S HOW IT WORKS.

[00:23:20.920]
THE NIAGARA POWER PROJECT, LOCATED
ABOUT 4 1/2 MILES DOWNSTREAM

[00:23:25.580]
FROM NIAGARA FALLS, CONSISTS
OF TWO MAIN FACILITIES:

[00:23:29.880]
THE ROBERT MOSES NIAGARA POWER
PLANT WITH 13 GENERATING UNITS

[00:23:34.630]
AND THE LEWISTOWN
PUMP GENERATING PLANT

[00:23:36.910]
WITH 12 PUMP TURBINE
GENERATING UNITS.

[00:23:40.150]
BETWEEN THE TWO PLANTS IS A
LARGE FOREBAY, OR OPEN CANAL.

[00:23:44.770]
IT'S ALMOST 1 MILE LONG
AND ABOUT 500 FEET WIDE.

[00:23:49.260]
BEHIND THE LEWISTOWN PLANT
IS A 1,900-ACRE RESERVOIR,

[00:23:53.980]
WHICH IS LIKE A LARGE BATHTUB,
AND THAT HOLDS ADDITIONAL SUPPLIES

[00:23:57.980]
OF LIQUID FUEL, ABOUT 20
BILLION GALLONS WORTH.

[00:24:02.810]
BASICALLY, WATER IS DIVERTED
FROM THE NIAGARA RIVER,

[00:24:06.530]
UP TO 600,000 GALLONS A SECOND,

[00:24:09.100]
AND TRAVELS THROUGH TWO
UNDERGROUND CONDUITS, OR TUNNELS,

[00:24:14.170]
UNDER THE CITY OF NIAGARA
FALLS AND THE SURROUNDING TOWNS

[00:24:17.960]
TO THE PROJECT'S FOREBAY.

[00:24:20.450]
FROM THERE, WATER FLOWING THROUGH
THE ROBERT MOSES PLANT SPINS THE

[00:24:24.810]
TURBINES THAT POWER THE GENERATORS,
CONVERTING MECHANICAL ENERGY

[00:24:29.800]
INTO ELECTRICAL ENERGY.

[00:24:32.200]
AT NIGHT, WHEN ELECTRICITY DEMAND
IS LOW, THE LEWISTOWN UNITS OPERATE

[00:24:37.650]
AS PUMPS, CARRYING
WATER FROM THE FOREBAY

[00:24:40.870]
UP TO THE PLANT'S RESERVOIR.

[00:24:42.970]
THEN, DURING THE DAY, WHEN
ELECTRICITY USE INCREASES,

[00:24:47.420]
THE LEWISTOWN PUMPS
REVERSE DIRECTION

[00:24:50.220]
AND BECOME TURBINE
GENERATORS SIMILAR TO THOSE

[00:24:53.470]
AT THE ROBERT MOSES PLANT.

[00:24:55.390]
THE WATER THEN FLOWS BACK INTO
THE FOREBAY AND IS USED AGAIN

[00:24:59.830]
AT THE ROBERT MOSES PLANT.

[00:25:02.260]
USING THE WATER TWICE TO
PRODUCE ELECTRICITY ALLOWS US

[00:25:06.340]
TO INCREASE OUR EFFICIENCY
AND PRODUCTION.

[00:25:10.360]
YOU LEARNED EARLIER THAT
THERE ARE NUMEROUS WAYS

[00:25:12.890]
TO PRODUCE ELECTRICITY
USING DIFFERENT FUELS.

[00:25:15.790]
WELL, HERE AT A HYDROELECTRIC
PROJECT, WE USE WATER AS OUR FUEL,

[00:25:20.540]
SO HYDROELECTRIC POWER
IS ONE OF THE CLEANEST

[00:25:22.930]
AND ENVIRONMENTALLY FRIENDLY
WAYS TO PRODUCE ELECTRICITY.

[00:25:26.870]
IS ALL THE WATER IN THE
RIVER USED TO MAKE POWER?

[00:25:29.620]
THAT'S A VERY GOOD QUESTION,
AND THE ANSWER IS NO.

[00:25:32.910]
IF ALL THE WATER IN THE
NIAGARA RIVER WAS USED

[00:25:35.660]
FOR POWER PRODUCTION,
THERE WOULDN'T BE ANY GOING

[00:25:38.020]
OVER NIAGARA FALLS, AND
BECAUSE THE FALLS IS

[00:25:41.120]
SUCH AN INTERNATIONAL
ATTRACTION, THE UNITED STATES

[00:25:44.370]
AND CANADA SIGNED A TREATY IN 1950,

[00:25:47.210]
AND THAT TREATY REGULATES THE
AMOUNT OF WATER THAT MUST FLOW

[00:25:50.810]
OVER NIAGARA FALLS AT
ALL TIMES OF THE YEAR.

[00:25:54.140]
THE TREATY SAYS THAT
DURING THE TOURIST SEASON,

[00:25:56.940]
100,000 CUBIC FEET PER SECOND
MUST FLOW OVER NIAGARA FALLS.

[00:26:02.490]
A CUBIC FOOT IS EQUAL TO 7
1/2 GALLONS, SO IF WE MULTIPLY

[00:26:07.670]
THAT BY 100,000 CUBIC
FEET PER SECOND,

[00:26:11.340]
THERE IS APPROXIMATELY 750,000
GALLONS OF WATER PER SECOND FLOWING

[00:26:16.350]
OVER NIAGARA FALLS
DURING THE TOURIST SEASON.

[00:26:19.440]
SO AFTER THE POWER IS
MADE, WHERE DOES IT GO?

[00:26:22.000]
THE POWER GENERATED HERE
AT THE NIAGARA PROJECT GOES

[00:26:25.390]
TO A VARIETY OF CUSTOMERS.

[00:26:27.260]
MUCH OF IT STAYS RIGHT
HERE IN WESTERN NEW YORK

[00:26:30.010]
FOR BUSINESS AND INDUSTRY TO USE.

[00:26:32.360]
SOME ALSO GOES TO
RESIDENTIAL CUSTOMERS BOTH HERE

[00:26:35.750]
IN WESTERN NEW YORK AS WELL
AS THROUGHOUT NEW YORK STATE.

[00:26:39.250]
AND A SMALL PERCENTAGE OF THE POWER
GENERATED HERE AT NIAGARA IS SOLD

[00:26:43.500]
TO NEIGHBORING STATES.

[00:26:44.700]
CAN YOU TELL US WHAT CAN
CAUSE A POWER OUTAGE?

[00:26:48.140]
POWER OUTAGES CAN BE CAUSED
BY A NUMBER OF FACTORS.

[00:26:51.970]
SOME CAN SIMPLY BE
EQUIPMENT FAILURES.

[00:26:55.280]
OTHER TIMES, SEVERE STORMS
-- EITHER WIND STORMS,

[00:26:58.560]
OR IN THE NORTHERN
CLIMATES, ICE STORMS --

[00:27:01.350]
CAN CAUSE DAMAGE TO POWER LINES
AND THEREBY CAUSE A POWER OUTAGE.

[00:27:05.830]
SOMETIMES IT'S JUST
OUR CUSTOMERS REQUIRING

[00:27:08.990]
AND USING MORE ELECTRICITY THAN
THE POWER PLANT CAN GENERATE.

[00:27:13.120]
THAT'LL OVERLOAD THE SYSTEM

[00:27:14.800]
AND SOMETIMES ALSO
CAUSE A POWER OUTAGE.

[00:27:17.380]
THANKS FOR TELLING US
ABOUT NIAGARA FALLS.

[00:27:19.840]
THANKS SO MUCH FOR STOPPING
BY, AND WE'LL SEE YOU LATER.

[00:27:23.540]
SO YOU CAN EITHER SET THIS RADIO
OUT IN THE SUN OR TURN THIS CRANK

[00:27:27.140]
ON THE SIDE, AND IT
PLAYS FOR HOURS.

[00:27:29.390]
PRETTY NEAT.

[00:27:29.740]
HOW DOES IT DO THAT?

[00:27:31.420]
WELL, THE SOLAR POWER
OR HAND CRANK CHARGES

[00:27:34.040]
UP THE RECHARGEABLE BATTERY
THAT'S INSIDE OF THE RADIO.

[00:27:37.050]
DID YOU HAVE IT THE OTHER
NIGHT WHEN THE POWER WENT OUT?

[00:27:39.340]
YEAH, IT WAS REALLY HANDY.

[00:27:40.650]
I COULD LISTEN TO KSNN EVEN
THOUGH THE ELECTRICITY WAS OUT.

[00:27:43.940]
THE PEOPLE ACROSS THE STREET
COULD USE IT RIGHT NOW.

[00:27:47.060]
WHAT'S THAT SOUND?

[00:27:48.250]
IS IT YOUR RADIO?

[00:27:49.200]
NO, I THINK IT'S KSNN.

[00:27:56.640]
I'M TED TUNE, AND THIS IS KSNN.

[00:27:59.540]
LAST NIGHT'S STORM KNOCKED
OUT POWER FOR THOUSANDS

[00:28:01.690]
OF CUSTOMERS IN WATTSVILLE.

[00:28:03.320]
JUST MOMENTS AGO, THE
POWER COMPANY REPORTS

[00:28:05.450]
THAT SERVICE HAS BEEN
RESTORED TO MOST OF THE AREA.

[00:28:08.510]
I.M. LISSNING IS STANDING BY.

[00:28:10.400]
I.M.?

[00:28:11.780]
TED, I'M IN WATTSVILLE
WITH MR. EEL ECTRIC.

[00:28:15.750]
NOW, MR. ECTRIC, YOU STILL DO
NOT HAVE POWER, IS THAT RIGHT?

[00:28:20.810]
UH, THAT IS CORRECT.

[00:28:24.190]
DOES HAVING NO POWER MAKE IT HARDER
FOR YOU, AN ELECTRIC EEL, TO STUN

[00:28:30.290]
AND THEN EAT YOUR PREY?

[00:28:32.240]
UH, NO.

[00:28:33.430]
YOU SEE, IT'S MY HOUSE
THAT'S WITHOUT POWER.

[00:28:36.690]
I, ON THE OTHER FIN, AM
FULLY CAPABLE OF DELIVERING

[00:28:40.480]
UP TO 600 VOLTS JUST LIKE THAT.

[00:28:44.430]
B-B-B-BACK TO YOU, T-T-T-TED.

[00:28:50.210]
THAT WAS I.M. LISSNING WITH
ANOTHER SUPERCHARGED REPORT.

[00:28:53.720]
IN OTHER NEWS, A PROPOSED
MAJOR HIGHWAY EXPANSION

[00:28:56.210]
THROUGH THE CHARLES SCHULZ
NATIONAL FOREST WAS VETOED

[00:28:58.720]
BY THE PRESIDENT.

[00:28:59.850]
LET'S GET BACK TO WORK AND FIGURE

[00:29:01.420]
OUT WHY THERE'S STILL NO
POWER ACROSS THE STREET.

[00:29:03.780]
WHAT DO WE KNOW?

[00:29:04.410]
WE KNOW THAT THERE'S NO LIGHTNING
DAMAGE AT THE POWER SOURCE.

[00:29:07.600]
BECAUSE IF THERE WAS A
PROBLEM AT THE POWER PLANT,

[00:29:09.480]
THE WHOLE AREA WOULD
BE WITHOUT ELECTRICITY.

[00:29:11.540]
WE ALSO KNOW THERE'S
NO EQUIPMENT DAMAGE,

[00:29:14.240]
AND THAT POWER'S BEEN
RESTORED ACROSS THE AREA.

[00:29:16.910]
WHAT DO WE NEED TO KNOW?

[00:29:17.710]
WE NEED TO KNOW WHY THE POWER
IS OUT ONLY ACROSS THE STREET.

[00:29:21.530]
WHEN WE TALKED TO NIAGARA FALLS,

[00:29:23.320]
THEY TAUGHT US HOW POWER
TRAVELS IN A CIRCUIT.

[00:29:25.740]
SO I THINK WE NEED TO KNOW WHAT A
CIRCUIT IS AND HOW A CIRCUIT WORKS.

[00:29:29.340]
OKAY, SO WHERE DO WE GO?

[00:29:30.700]
LET'S GO TO THE HOUSES
ACROSS THE STREET.

[00:29:33.830]
THAT'S WHERE THE POWER'S OUT.

[00:29:35.050]
ALL RIGHT, I'LL CHANGE
OUR HYPOTHESIS TO SAY

[00:29:38.350]
THAT THE PROBLEM IS SOMEWHERE
BETWEEN THE POWER SOURCE

[00:29:40.540]
AND THE HOUSES ACROSS THE STREET.

[00:29:42.420]
I'LL TYPE THESE NOTES
INTO THE COMPUTER.

[00:29:45.000]
I THINK WE'RE ON THE RIGHT TRACK.

[00:29:46.950]
WE MUST BE GETTING CLOSER.

[00:29:49.360]
SO DR. D, HAVE YOU FIGURED OUT
WHAT'S WRONG WITH YOUR TRAIN YET?

[00:29:52.820]
NO, I WORKED ON IT SOME MORE AND I
CHECKED THE ELECTRICAL CONNECTIONS

[00:29:55.680]
TO MAKE SURE THEY WERE TIGHT.

[00:29:57.090]
THE TRAIN IS STILL NOT
GETTING ELECTRICITY.

[00:29:59.960]
WHAT ARE YOU GOING TO DO NOW?

[00:30:01.510]
WELL, I HAVE SOME ELECTRICAL
TEST EQUIPMENT ON MY WORKBENCH;

[00:30:03.780]
I THINK I'LL UNPLUG THE POWER UNIT,

[00:30:05.470]
TAKE IT TO MY WORK BENCH
TONIGHT AND CHECK IT OUT.

[00:30:07.660]
HOPEFULLY, THIS WILL
BRING US SOME CONCLUSIONS.

[00:30:10.420]
GOOD LUCK.

[00:30:12.550]
SO WHAT'S UP?

[00:30:13.740]
HOW WILL LEARNING ABOUT THE
POWER PLANT HELP THE TREE HOUSE

[00:30:16.100]
DETECTIVES SOLVE THEIR CASE?

[00:30:18.200]
ARE THEY RIGHT TO
REVISE THEIR HYPOTHESIS?

[00:30:21.120]
WHAT DO YOU THINK IS
WRONG WITH DR. D'S TRAIN?

[00:30:24.230]
WE'LL HAVE MORE ON THE
NEXT SEGMENT OF THE CASE

[00:30:26.970]
OF THE ELECTRICITY MYSTERY.

[00:30:28.440]
I DID A WEB SEARCH ON ELECTRICITY

[00:30:34.340]
AND FOUND SOME REALLY
INTERESTING FACTS.

[00:30:36.220]
WELL, YOU KNOW ABOUT
TESLA OR ALESSANDRO VOLTA?

[00:30:39.130]
I THINK I'VE HEARD OF THEM.

[00:30:40.600]
I FOUND A VIDEO CLIP
ABOUT THE HISTORY

[00:30:42.200]
OF ELECTRICITY ON THE INTERNET.

[00:30:44.850]
LET'S WATCH IT.

[00:30:46.930]
MAYBE WE'LL FIND SOME
INTERESTING FACTS.

[00:30:53.950]
AND NOW, THE HISTORY
OF ELECTRICITY.

[00:30:57.410]
HERE'S DR. TEXTBOOK.

[00:31:00.650]
HELLO.

[00:31:02.460]
MAYBE YOU THINK THAT ONE OR TWO
PEOPLE DISCOVERED ELECTRICITY.

[00:31:06.510]
WELL, ACTUALLY, ELECTRICITY
IS ALL AROUND US.

[00:31:08.800]
IT OCCURS IN NATURE.

[00:31:09.970]
OH, AH!

[00:31:12.030]
VERY FUNNY.

[00:31:14.580]
AN ELECTRIC BUZZER.

[00:31:16.380]
NOW, YOU'VE PROBABLY
HEARD SOME STORY

[00:31:18.190]
ABOUT BEN FRANKLIN FLYING HIS KITE.

[00:31:20.270]
WELL, DON'T BELIEVE FOR ONE SECOND
THAT MR. FRANKLIN WAS STANDING

[00:31:22.920]
OUT IN A WET FIELD
WITH LIGHTNING RAGING

[00:31:24.900]
ABOUT HIM HOLDING ONTO A BRASS KEY.

[00:31:26.880]
NO, HE ACTUALLY WAS STANDING IN
THE DISTANCE OBSERVING THE KITE,

[00:31:31.200]
TAKING NOTES, AND
WHAT HE FOUND OUT WAS

[00:31:33.530]
THAT LIGHTNING IS ACTUALLY
AN ELECTRICAL SPARK.

[00:31:37.110]
NOW, ON TO ALESSANDRO VOLTA.

[00:31:40.150]
MR. VOLTA WAS THE FIRST MAN TO
BUILD A BATTERY, AND HE DID THIS

[00:31:43.890]
BY TAKING SMALL PLATES OF COPPER
AND ZINC AND PUTTING MOIST PIECES

[00:31:47.760]
OF PAPER IN BETWEEN IT.

[00:31:49.210]
SO AS AN ODE TO VOLTA, I
WILL TAKE THIS 9-VOLT BATTERY

[00:31:53.170]
AND STICK IT ON MY MOIST TONGUE.

[00:31:55.120]
NOT A VERY GOOD IDEA.

[00:31:58.950]
WELL, THOMAS EDISON
BUILT A GENERATOR

[00:32:03.910]
TO MAKE ELECTRICAL CURRENT,

[00:32:05.920]
BUT IT ACTUALLY WAS A MAN CALLED
NIKOLA TESLA WHO FOUND OUT THAT

[00:32:09.140]
BY ALTERNATING THE ELECTRONS IN AN
ELECTRICAL CIRCUIT WAS A BETTER WAY

[00:32:13.530]
TO PRODUCE ELECTRICITY, AND THIS
WE CALL ALTERNATING CURRENT,

[00:32:17.300]
AND THE FIRST PLACE THIS
OCCURRED WAS IN NIAGARA FALLS.

[00:32:23.180]
WAIT, THERE'S MORE TO LEARN.

[00:32:24.900]
THIS HAS BEEN THE
HISTORY OF ELECTRICITY.

[00:32:27.510]
YOU KNOW, STUDYING ELECTRICITY
IS REALLY INTERESTING.

[00:32:32.380]
I THINK IF WE'RE GOING TO SOLVE
THIS PROBLEM, WE NEED TO LEARN MORE

[00:32:35.180]
ABOUT ELECTRICITY AND HOW
IT COMES INTO OUR HOMES.

[00:32:37.920]
HMM, I WONDER HOW A CIRCUIT WORKS?

[00:32:40.240]
MAYBE WE'LL GET A
BETTER UNDERSTANDING

[00:32:41.690]
FROM TOMORROW'S CLASSROOM LESSON.

[00:32:44.090]
WE HAVE A SPECIAL GUEST WITH US
TODAY TO TEACH US SOME BASICS

[00:32:47.220]
ABOUT ELECTRICAL CIRCUITS:
WE HAVE MR. RICK WALKER,

[00:32:50.860]
WHO IS AN ELECTRICAL ENGINEER
FROM NASA LANGLEY RESEARCH CENTER.

[00:32:54.740]
HOW MANY PEOPLE THINK
ELECTRICITY IS MYSTERIOUS?

[00:32:58.930]
WHY DO YOU THINK ELECTRICITY
IS SO MYSTERIOUS?

[00:33:01.510]
IT'S PROBABLY BECAUSE
WE CAN'T SEE IT.

[00:33:03.570]
THAT'S A PRETTY COMMON
ANSWER, JACOB.

[00:33:05.390]
MOST PEOPLE HAVE A HARD TIME
UNDERSTANDING THINGS THEY

[00:33:07.360]
CAN'T SEE.

[00:33:08.420]
SO TO HELP US SEE HOW ELECTRICITY
WORKS, WE'RE GOING TO USE SOMETHING

[00:33:11.450]
THAT WE ALL KNOW ABOUT.

[00:33:12.940]
LET'S GO OUTSIDE AND LEARN
ABOUT THE BASIC COMPONENTS

[00:33:15.000]
OF A CIRCUIT USING A
FIRE TRUCK AND WATER.

[00:33:20.540]
COOL.

[00:33:20.650]
TODAY WE'RE WITH FIRE FIGHTERS

[00:33:21.780]
FROM THE FOX HILL COMPANY
NUMBER 5 IN HAMPTON, VIRGINIA.

[00:33:24.110]
HEY, GUYS.

[00:33:24.800]
HI, RICK.

[00:33:25.990]
LET'S SAY THESE GUYS WERE
ON THE SCENE OF A FIRE.

[00:33:27.910]
WHAT ARE SOME THINGS
THAT THEY WOULD NEED

[00:33:29.210]
TO BE ABLE TO PUT THE FIRE OUT?

[00:33:30.800]
WATER.

[00:33:31.970]
AND A FIRE TRUCK.

[00:33:33.140]
THAT'S RIGHT, WE'LL NEED A
FIRE TRUCK FILLED WITH WATER.

[00:33:35.040]
WHAT ELSE?

[00:33:35.790]
WHAT ABOUT A FIRE HOSE?

[00:33:37.080]
ALL RIGHT, NOW HOW DO THE
FIREFIGHTERS GET THE WATER

[00:33:39.130]
TO THE FIRE?

[00:33:40.430]
THEY HOOK UP THE HOSE TO THE TRUCK.

[00:33:42.220]
RIGHT, WE DEFINITELY HAVE TO HAVE
THE HOSE HOOKED UP TO THE TRUCK.

[00:33:44.890]
SO, WHAT WE HAVE HERE ARE THE
BASIC COMPONENTS OF A CIRCUIT.

[00:33:48.570]
THEY HAVE A POWER SOURCE, THEY HAVE
CONDUCTORS OR WIRES, AND A LOAD.

[00:33:52.590]
WHAT DO YOU MEAN BY A LOAD?

[00:33:54.690]
IN A CIRCUIT, A LOAD IS A DEVICE
THAT CONVERTS ELECTRICAL ENERGY

[00:33:57.520]
INTO SOME OTHER FORM OF ENERGY.

[00:33:59.060]
FOR EXAMPLE, IN AN ELECTRICAL
CIRCUIT, WE USE A LIGHT BULB

[00:34:02.310]
TO CONVERT ELECTRICITY INTO LIGHT.

[00:34:04.340]
THE POWER SOURCE IS WHAT
SUPPLIES OUR CIRCUIT

[00:34:06.260]
WITH THE ENERGY TO DO WORK.

[00:34:07.960]
FOR EXAMPLE, A BATTERY
CREATES ELECTRICAL PRESSURE,

[00:34:10.770]
CALLED VOLTAGE, THAT WILL PUSH
ELECTRONS THROUGH THE CIRCUIT.

[00:34:13.420]
ON THE FIRE TRUCK, A PUMP
CREATES WATER PRESSURE.

[00:34:16.330]
THE PRESSURE WILL PUSH THE
WATER OUT IF THERE'S A PATH

[00:34:18.390]
FOR THE WATER TO FLOW.

[00:34:24.470]
THE WATER TRAVELS TO THE LOAD,
WHICH IS OUR WATER CANNON.

[00:34:27.590]
OKAY, GUYS, WHENEVER YOU'RE READY.

[00:34:29.120]
WHOAH.

[00:34:31.170]
[00:34:38.060]
WOW.

[00:34:40.630]
COOL.

[00:34:43.080]
[00:34:46.370]
NOW LET'S GO INSIDE AND COMPARE
THIS TO AN ELECTRICAL CIRCUIT.

[00:34:50.600]
WHO REMEMBERS WHAT COMPONENTS WE
NEED TO MAKE UP A SIMPLE CIRCUIT?

[00:34:54.380]
[00:34:55.390]
P.J.?

[00:34:55.740]
A POWER SOURCE, CONDUCTORS
OR THE WIRES, AND A LOAD.

[00:34:59.670]
THAT'S RIGHT.

[00:35:00.820]
WHAT WE'RE GOING TO DO
IS, WE'LL USE THIS BATTERY

[00:35:02.170]
AS OUR POWER SOURCE, THE
WIRES AS OUR CONDUCTORS,

[00:35:04.840]
AND THIS LAMP WILL BE OUR LOAD.

[00:35:06.130]
IF WE CONNECT THEM IN THE RIGHT
ORDER, THE CIRCUIT WILL BE CLOSED,

[00:35:10.210]
AND THE LIGHTBULB WILL LIGHT.

[00:35:12.090]
BASICALLY WHAT WE HAVE HERE IS THE
BATTERY IS CREATING AN ELECTRICAL

[00:35:14.860]
POTENTIAL CALLED VOLTAGE,
WHICH IS PUSHING THE ELECTRONS

[00:35:17.650]
THROUGH THE WIRES,
UP TO THE LIGHTBULB,

[00:35:20.060]
AND BACK AROUND TO THE
OTHER SIDE OF THE BATTERY.

[00:35:22.210]
WHEN THIS CIRCUIT'S CLOSED,
THE LIGHTBULB LIGHTS.

[00:35:24.800]
IT'S IMPORTANT TO REMEMBER HERE

[00:35:25.980]
THAT THE BATTERY IS NOT
CREATING ELECTRICITY,

[00:35:28.660]
BUT MERELY PUSHING
ELECTRONS AROUND THE CIRCUIT.

[00:35:31.250]
SO WHAT WOULD YOU CALL IT IF YOU
DISCONNECTED ONE OF THE WIRES?

[00:35:34.630]
IF IT'S CALLED A CLOSED
CIRCUIT WHEN THE LAMP IS LIT,

[00:35:36.850]
THEN WOULD IT BE CALLED
AN OPEN CIRCUIT

[00:35:38.560]
WHEN THE LAMP DOESN'T LIGHT?

[00:35:39.760]
THAT'S RIGHT.

[00:35:40.600]
FOR EXAMPLE, THE LIGHTS
IN OUR ROOM RIGHT NOW,

[00:35:42.480]
WE HAVE A CLOSED CIRCUIT.

[00:35:43.890]
BUT IF I WAS TO GO OVER TO THE WALL

[00:35:45.450]
AND FLIP THE SWITCH,
WHAT WOULD WE HAVE?

[00:35:47.550]
YOU CREATED AN OPEN CIRCUIT.

[00:35:50.560]
EXACTLY.

[00:35:51.700]
AT HOME, YOU USE DEVICES LIKE
SWITCHES AND CIRCUIT BREAKERS

[00:35:54.560]
AND FUSES TO MAKE OPEN CIRCUITS.

[00:35:57.360]
THE PEOPLE AT NIAGARA FALLS TOLD
US POWER IS GENERATED BY WATER

[00:36:02.740]
THAT FLOWS UNDER THE FALLS.

[00:36:04.080]
THAT'S COOL.

[00:36:04.820]
IN MY CLASS, WE WATCHED THE FIRE
DEPARTMENT DEMONSTRATE A SIMPLE

[00:36:07.270]
CIRCUIT WITH THEIR FIRE TRUCK.

[00:36:08.780]
IT REALLY HELPED ME
UNDERSTAND HOW A CIRCUIT WORKS.

[00:36:11.180]
SO ARE ALL HOMES ON
ONE SERIES CIRCUIT?

[00:36:14.500]
HMM.

[00:36:15.940]
BECAUSE IF ONE HOUSE LOST POWER,
DOESN'T EVERY HOUSE LOSE POWER?

[00:36:19.190]
YEAH, THEY'RE JUST
LIKE CHRISTMAS LIGHTS.

[00:36:21.180]
IF ONE GOES OUT, THEY ALL GO OUT.

[00:36:22.800]
I DON'T THINK THAT'S HOW IT WORKS.

[00:36:24.550]
I'LL BET IT DOES.

[00:36:25.380]
WHY DO YOU THINK ALL THE HOUSES
ARE OUT ACROSS THE STREET?

[00:36:27.750]
BUT EVERY HOUSE IN OUR
TOWN ISN'T WITHOUT POWER.

[00:36:29.750]
OUR TREE HOUSE STILL HAS POWER.

[00:36:31.010]
I DON'T THINK OUR NEIGHBORHOOD
IS ON ONE SIMPLE CIRCUIT.

[00:36:33.400]
I THINK OUR HOUSES'
CIRCUITS ARE COMPLEX TOO.

[00:36:35.980]
WHEN YOU TURN OFF THE LIGHT SWITCH,
THE WHOLE HOUSE DOESN'T GO DARK.

[00:36:38.560]
I THINK WE NEED TO GO
BACK TO THE PROBLEM BOARD.

[00:36:41.980]
WE LEARNED HOW POWER IS
GENERATED AT A POWER PLANT

[00:36:45.790]
AND HOW EVERYTHING
RUNS ON A CIRCUIT.

[00:36:47.300]
WE KNOW THAT A SIMPLE CIRCUIT
IS MADE UP OF: A POWER SOURCE,

[00:36:50.810]
CONDUCTORS, AND A LOAD.

[00:36:51.880]
AND WE KNOW THAT OUR NEIGHBORHOOD
DOES NOT RUN ON A SIMPLE CIRCUIT.

[00:36:54.620]
I THINK WE NEED TO KNOW A LITTLE
MORE ABOUT THESE COMPLEX CIRCUITS.

[00:36:58.500]
OKAY, WHERE CAN WE
FIND INFORMATION?

[00:37:00.380]
I HAVE AN IDEA; LET'S SEE
IF ANYONE ON THE NASA "WHY?"

[00:37:02.890]
FILES KID'S CLUB HAS DONE ANY
RESEARCH ON ELECTRICLA CIRCUITS.

[00:37:06.470]
OK, I'LL SEND OUT AN E-MAIL
AND CHECK ON OUR NASA "WHY?"

[00:37:09.030]
FILES WEBSITE.

[00:37:10.580]
HEY, I FOUND IT.

[00:37:10.990]
A CLASSROOM IN MONTREAL,
QUEBEC, DID SOME EXPERIMENTATION

[00:37:16.030]
WITH COMPLEX CIRCUITS.

[00:37:17.270]
COOL, LET'S DIAL THEM UP.

[00:37:19.430]
BONJOUR, MON NOME EST ALEX
ROBERTS DANS L'ECOLE BEACON HILL,

[00:37:27.790]
CINQUIEME ANNEE AVEC MR.
ROBIN, QUEBEC, CANADA.

[00:37:31.050]
HI, MY NAME IS ALEX ROBERTS
IN BEACON HILL SCHOOL,

[00:37:34.210]
FIFTH GRADE WITH MR.
ROBIN, QUEBEC, CANADA.

[00:37:38.200]
HI, CAN YOU TELL US MORE ABOUT
YOUR EXPERIMENTS WITH CIRCUITS?

[00:37:41.740]
WE'RE MAKING DIFFERENT TYPES OF
CIRCUITS USING D-CELL BATTERIES,

[00:37:45.040]
LIGHT BULBS, BATTERY
HOLDERS, AND WIRES.

[00:37:47.830]
WHAT DO YOU MEAN,
DIFFERENT TYPES OF CIRCUITS?

[00:37:50.110]
OUR JOB WAS TO EXPERIMENT ON
DIFFERENT COMBINATIONS OF CIRCUITS

[00:37:53.770]
AND OBSERVE WHAT HAPPENS.

[00:37:55.250]
WE MADE A HYPOTHESIS OF WHAT
WE THOUGHT WOULD HAPPEN.

[00:37:58.290]
ONE STUDENT MADE A
LIGHTBULB REALLY BRIGHT

[00:38:00.370]
WITH TWO BATTERIES AND ONE BULB.

[00:38:02.470]
ANOTHER STUDENT LIT TWO
BULBS WITH JUST ONE BATTERY.

[00:38:05.560]
HE FOUND OUT THAT IF YOU
UNSCREWED ONE OF THE BULBS,

[00:38:07.970]
THE OTHER WENT OUT TOO.

[00:38:09.560]
THIS IS CALLED A SERIES CIRCUIT.

[00:38:11.220]
AH-HA!

[00:38:12.090]
I WAS RIGHT.

[00:38:13.170]
IF ONE LIGHT BULB GOES
OUT, THEY ALL GO OUT.

[00:38:16.180]
WELL, OUR TEACHER ASKED US TO TRY
AND DESIGN A CIRCUIT WITH MORE

[00:38:19.950]
THAN ONE LOAD, LIKE A BULB,
BUZZER, OR MOTOR THAT WILL KEEP

[00:38:23.700]
ON WORKING IF WE REMOVE
ONE OF THE LOADS.

[00:38:26.200]
ONE STUDENT DREW A DIAGRAM WITH THE
SAME NUMBERS OF BULBS AND BATTERIES

[00:38:29.210]
AND USED MORE WIRES
GOING TO EACH BULB.

[00:38:32.030]
DID YOU TRY UNSCREWING
ONE LIGHT BULB?

[00:38:34.300]
YES.

[00:38:34.660]
WHEN WE UNSCREWED ONE LIGHT
BULB, THE OTHER STAYED LIT.

[00:38:37.430]
IT WAS ALMOST LIKE
THE ELECTRICITY WENT

[00:38:39.320]
AROUND THE UNSCREWED
BULB TO GET TO THE OTHER.

[00:38:41.740]
WHAT?

[00:38:42.090]
THAT CAN'T BE RIGHT.

[00:38:43.100]
HOW IS THAT DIFFERENT FROM
THE SERIES CIRCUIT YOU MADE?

[00:38:46.210]
IN THE SERIES CIRCUIT,
THE ELECTRICITY TRAVELED

[00:38:48.420]
IN A CIRCLE THROUGH EACH BULB.

[00:38:49.850]
BUT IN A PARALLEL CIRCUIT, IT
TRAVELED TO AND AROUND EACH BULB.

[00:38:53.890]
LOOK AT THESE TWO CIRCUITS.

[00:38:55.320]
THE FIRST ONE IS CALLED
A SERIES CIRCUIT.

[00:38:57.230]
IT IS BASICALLY A CIRCLE.

[00:38:59.300]
WHEN YOU REMOVE ONE BULB, THE FLOW
OF THE ELECTRICITY IS INTERRUPTED.

[00:39:03.430]
THE SECOND ONE IS CALLED
A PARALLEL CIRCUIT.

[00:39:05.650]
THE ELECTRICITY GOES TO
EACH RESISTOR SEPARATELY

[00:39:09.280]
AND BYPASSES THE ONES
NOT CONNECTED.

[00:39:11.660]
AND THAT'S THE DIFFERENCE BETWEEN
PARALLEL AND SERIES CIRCUIT.

[00:39:14.850]
OUR TEACHER SAID THAT WE
CAN MAKE COMPLEX CIRCUITS

[00:39:17.490]
BY COMBINING PARALLEL AND SERIES
CIRCUIT INTO ONE BIG CIRCUIT.

[00:39:21.670]
THAT'S WHAT WE'RE
GOING TO TRY NEXT.

[00:39:23.550]
OK, THIS IS GREAT INFORMATION.

[00:39:25.170]
THANKS FOR YOUR HELP.

[00:39:27.970]
AU REVOIR, LES AMIS.

[00:39:28.920]
BYE.

[00:39:29.280]
HEY, MATTHEW, WHAT ARE YOU DOING?

[00:39:34.050]
I'M JUST PLAYING WITH
THESE CHRISTMAS LIGHTS.

[00:39:36.280]
I GUESS THESE LIGHTS ARE
WIRED UP IN A SERIES CIRCUIT,

[00:39:38.440]
BECAUSE WHEN I TAKE ONE
LIGHTBULB OUT, THEY ALL GO OUT.

[00:39:40.630]
BUT NOT ALL THE LIGHTS GO OUT.

[00:39:42.050]
I HAVE TO TAKE ANOTHER LIGHTBULB
IN A DIFFERENT PART OF THE STRAND

[00:39:44.680]
TO GET THE OTHER LIGHTS TO GO OUT.

[00:39:46.250]
SO IS IT A PARALLEL
CIRCUIT OR A SERIES CIRCUIT?

[00:39:49.680]
THESE LIGHTS ARE DEFINITELY
A SERIES CIRCUIT.

[00:39:51.670]
BUT THE WHOLE STRAND IS A
PARALLEL CIRCUIT, TWO SETS OF 50.

[00:39:55.260]
I GUESS IT'S A COMBINATION OF BOTH.

[00:39:58.050]
EACH SECTION IS WIRED IN
A PARALLEL, BUT THE BULBS

[00:40:01.010]
WITHIN EACH SECTION ARE
WIRED UP IN A SERIES.

[00:40:04.080]
HEY, LOOK, ANOTHER KSNN
REPORT IS COMING ON.

[00:40:11.190]
I'M TED TUNE, AND THIS IS KSNN.

[00:40:13.980]
OFFICIALS FROM THE
POWER COMPANY REPORT

[00:40:15.730]
THAT ALL MAJOR CIRCUITS
APPEAR TO BE WORKING.

[00:40:18.400]
KSNN'S OWN I.M. LISSNING
IS ON THE SCENE

[00:40:21.010]
AT ONE HOUSE STILL WITHOUT POWER.

[00:40:23.280]
I.M.?

[00:40:24.330]
TED, YOU COULD PROBABLY SEE ME IF
MY, AHEM, CAMERAMAN HAD REMEMBERED

[00:40:30.450]
TO BRING FRESH BATTERIES
FOR THE LIGHTS.

[00:40:33.820]
AT THE MOMENT, I'M
STANDING OUTSIDE THE HOME

[00:40:36.380]
OF A MR. E. HIS NEIGHBORHOOD
IS THE ONLY ONE

[00:40:39.970]
THAT HAS NO POWER TONIGHT.

[00:40:41.800]
THE POWER COMPANY REPORTS,
HOWEVER, THAT ALL OVERHEAD LINES

[00:40:45.700]
THAT WERE DAMAGED BY THE RECENT
STORM HAVE BEEN REPAIRED.

[00:40:49.120]
WHAT IS CAUSING THE BLACKOUT
IN MR. E'S NEIGHBORHOOD?

[00:40:53.750]
WE MAY NEVER KNOW.

[00:40:54.460]
BACK TO YOU, TED.

[00:40:56.680]
THANK YOU, I.M., FOR THAT
ELECTRIFYING ACCOUNT.

[00:40:59.040]
I'LL BET NEXT MONTH'S ELECTRIC BILL

[00:41:00.560]
THAT THE TREE HOUSE DETECTIVES
CAN SOLVE THIS CURRENT CASE.

[00:41:03.700]
"CURRENT," HA, GET IT?

[00:41:05.580]
HA, HA, HA.

[00:41:06.040]
IF ALL OF THE CIRCUITS ARE WORKING,

[00:41:07.820]
THEN THE PROBLEM MUST BE PRETTY
CLOSE TO OUR NEIGHBORHOOD.

[00:41:10.970]
MAYBE THE PROBLEM IS
INSIDE MR. E'S HOUSE?

[00:41:13.020]
WHAT DO YOU WANT TO DO,

[00:41:13.770]
SNOOP AROUND MR. E'S
HOUSE WHEN HE'S NOT THERE?

[00:41:16.070]
WE CAN'T DO THAT, WE DON'T EVEN
KNOW WHAT WE'RE LOOKING FOR.

[00:41:18.740]
SO MAYBE WE SHOULD FIGURE OUT
HOW HOUSES ARE WIRED FIRST.

[00:41:21.300]
YOU MEAN, IN A PARALLEL
OR SERIES CIRCUIT?

[00:41:23.380]
EXACTLY.

[00:41:24.040]
LET'S ASK DR. D FOR HELP.

[00:41:26.300]
NOW WE'VE LEARNED ALL ABOUT
SERIES AND PARALLEL CIRCUITS,

[00:41:28.730]
AND WE'RE READY TO SEE
HOW OUR HOUSES ARE WIRED.

[00:41:31.160]
THE MODEL OF A HOUSE RIGHT HERE --
HOW CAN WE TELL WHETHER IT'S WIRED

[00:41:34.780]
IN SERIES OR IN PARALLEL?

[00:41:36.520]
WELL, WE KNOW THAT WHEN
SOMETHING IS WIRED IN PARALLEL,

[00:41:39.210]
WHEN ONE LAMP BURNS
OUT, OR IS TURNED OFF,

[00:41:41.290]
THE REST OF THEM STAY ON.

[00:41:42.760]
NOT ONLY THAT, BUT THE LIGHTS
THAT ARE STILL ON DON'T CHANGE.

[00:41:45.560]
THEY DON'T GET LIGHTER
AND THEY DON'T GET DIMMER.

[00:41:48.080]
LET'S TRY IT; LET'S TURN ONE

[00:41:49.190]
OF THESE LAMPS OFF
AND SEE WHAT HAPPENS.

[00:41:51.990]
THEY MUST BE IN PARALLEL,
BECAUSE IN SERIES,

[00:41:54.510]
ALL OF THE LIGHTS WOULD HAVE
GONE OUT WHEN ONE WAS TURNED OFF.

[00:41:57.510]
WHY IS IT IMPORTANT TO HAVE
A HOUSE WIRED IN PARALLEL?

[00:42:00.040]
WELL, IT'D BE REALLY ANNOYING
IF I WAS PLAYING ON THE COMPUTER

[00:42:02.720]
AND MY DAD TURNED A LAMP OFF
AND THE COMPUTER SHUT OFF.

[00:42:05.700]
OR IF I WAS IN MY ROOM
AND MY LIGHT GOT DIMMER

[00:42:07.920]
BECAUSE SOMEONE ELSE WAS
TURNING LIGHTS ON IN THE HOUSE.

[00:42:09.840]
AS MORE AND MORE DEVICES
ARE TURNED ON IN THE HOUSE,

[00:42:14.160]
THE NUMBER OF CHARGES FLOWING
THROUGH THIS CIRCUIT INCREASES.

[00:42:17.290]
EACH DEVICE GETS JUST THE
CURRENT THAT IT NEEDS,

[00:42:19.850]
BUT THE CURRENT FLOWING

[00:42:20.900]
IN THE SUPPLY WIRES MUST SUPPLY
CURRENT TO ALL THE DEVICES.

[00:42:24.450]
IF TOO MANY DEVICES ARE TURNED
ON, THE CURRENT IS TOO GREAT,

[00:42:27.920]
AND THE WIRES GET HOT.

[00:42:29.410]
THIS IS CALLED AN OVERLOAD.

[00:42:30.830]
THE CIRCUIT BREAKER TRIPS
AND TURNS THE CIRCUIT OFF.

[00:42:33.180]
I GUESS A CIRCUIT BREAKER IS
IN SERIES WITH EVERYTHING ELSE.

[00:42:36.290]
WHEN IT'S TURNED OFF,
WE HAVE AN OPEN CIRCUIT.

[00:42:39.120]
WHY WOULD YOU WANT EVERYTHING
ON THE CIRCUIT TO TURN OFF?

[00:42:40.900]
BECAUSE IF THE WIRES IN
THE WALLS GET TOO WARM,

[00:42:43.490]
THEN YOU'D HAVE A
FIRE ON YOUR HANDS.

[00:42:45.490]
THAT'S RIGHT.

[00:42:46.220]
NOW, SOMETIMES AN
APPLIANCE MALFUNCTIONS

[00:42:48.450]
AND CAUSES A SHORT CIRCUIT.

[00:42:49.770]
THAT BASICALLY MEANS THAT
TWO INCOMING WIRES TOUCH,

[00:42:52.420]
AND THERE'S A HUGE
CURRENT THAT RUNS

[00:42:54.550]
BECAUSE IT'S BYPASSING THE LOAD.

[00:42:55.970]
NOW, WHEN A SHORT CIRCUIT
OCCURS, WHAT HAPPENS?

[00:42:58.900]
SO, THE CIRCUIT BREAKER OPENS
THE CIRCUIT, SO NO HARM IS DONE.

[00:43:01.660]
THAT'S RIGHT, JUST LIKE THIS.

[00:43:03.930]
WHEN A CIRCUIT BREAKER IS TRIPPED,
YOU HAVE TO FIRST FIX THE PROBLEM,

[00:43:06.750]
THEN TURN THE CIRCUIT
BREAKER BACK ON.

[00:43:08.740]
JUST LIKE SEVERAL WALL OUTLETS
IN A HOUSE ARE CONNECTED TOGETHER

[00:43:11.870]
AND PROTECTED BY A CIRCUIT
BREAKER, SO THE HOUSES

[00:43:14.390]
IN THE NEIGHBORHOOD ARE
ALSO CONNECTED TOGETHER

[00:43:16.140]
BY A PARALLEL CIRCUIT, AND
PROTECTED BY A BIG CIRCUIT BREAKER.

[00:43:20.350]
SO HOW MANY HOUSES
ARE IN A CIRCUIT?

[00:43:22.170]
COULD BE AS MANY AS FOUR OR FIVE.

[00:43:24.030]
DOES THIS MEAN THAT IF THERE'S TOO
MUCH CURRENT GOING INTO A HOUSE

[00:43:26.390]
OR CIRCUIT, THE CIRCUIT
BREAKER OPENS THE CIRCUIT?

[00:43:29.540]
THAT'S RIGHT, WHEN THE CIRCUIT
IS OPEN, ALL THE HOUSES GO DARK.

[00:43:32.390]
WOW, WE MAY BE ONTO SOMETHING HERE.

[00:43:34.390]
BUT WHAT COULD CAUSE TOO MUCH
CURRENT TO GO TO THE HOUSES?

[00:43:36.960]
I GUESS A CIRCUIT
BREAKER ISN'T WORKING.

[00:43:39.260]
NO, I THINK IT'S MORE OF A PROBLEM

[00:43:41.430]
WITH THE WIRES RUNNING
TO THE HOUSES.

[00:43:43.550]
MAYBE THERE'S A SHORT
CIRCUIT IN THE WIRES.

[00:43:45.610]
GOOD THINKING.

[00:43:46.630]
WHY DIDN'T WE THINK
OF THIS EARLIER?

[00:43:48.430]
MAYBE BECAUSE THE WIRES

[00:43:49.810]
IN OUR NEIGHBORHOOD
ARE BURIED UNDERGROUND.

[00:43:51.640]
THAT WAY, THE SHORT CIRCUIT
COULD BE HIDDEN FROM VIEW.

[00:43:54.610]
THIS COULD BE TOUGH.

[00:43:56.020]
HEY DR.D, HAVE YOU HAD
ANY LUCK WITH YOUR TRAIN?

[00:43:58.430]
NOPE.

[00:43:59.460]
I CHECKED OUT THE POWER UNIT
ON THE WORK BENCH LAST NIGHT,

[00:44:02.910]
AND IT IS INDEED WORKING.

[00:44:04.010]
THIS IS REALLY GETTING PUZZLING.

[00:44:06.760]
WAIT A MINUTE -- TALKING
ABOUT SERIES

[00:44:08.840]
AND PARALLEL CIRCUITS
REMINDS ME OF SOMETHING ELSE

[00:44:11.140]
TO CHECK ON THE TRAIN.

[00:44:12.400]
WHAT'S THAT?

[00:44:13.460]
WELL, THE PIECES OF TRACK
FORM A SERIES CIRCUIT.

[00:44:15.940]
IF ONE OF THE LINKS OF THE TRACK
IS NOT PROPERLY PLUGGED IN,

[00:44:18.940]
WE HAVE AN OPEN CIRCUIT,
AND THE TRAIN WON'T WORK.

[00:44:21.530]
IN THE MEANTIME, I THINK WE
SHOULD REVISE OUR HYPOTHESIS TO:

[00:44:26.210]
THERE IS AN OPEN CIRCUIT
SOMEWHERE BETWEEN THE POWER SOURCE

[00:44:29.070]
AND THE HOUSES ACROSS THE STREET.

[00:44:30.890]
WELL, GOOD LUCK ON
SOLVING YOUR MYSTERY.

[00:44:32.620]
IT SOUNDS LIKE YOU'RE
GETTING CLOSE.

[00:44:35.650]
SO WHAT'S UP?

[00:44:37.040]
WHY DO YOU THINK THE POWER IS
STILL OFF ACROSS THE STREET?

[00:44:40.350]
WHAT WOULD HAPPEN IF YOUR
ENTIRE CITY WAS WIRED

[00:44:42.690]
ON ONE BIG SERIES CIRCUIT?

[00:44:45.430]
IS AN OPEN CIRCUIT KEEPING
DR. D'S TRAIN FROM WORKING?

[00:44:48.710]
DO YOU THINK THE TREE HOUSE
DETECTIVES ARE GETTING CLOSER

[00:44:51.110]
TO SOLVING THE CASE?

[00:44:52.810]
STAY TUNED FOR THE FINAL
INSTALLMENT OF THE CASE

[00:44:55.880]
OF THE ELECTRICITY MYSTERY.

[00:44:59.060]
SO WE'VE REVISED OUR
HYPOTHESIS TO SAY:

[00:45:05.450]
SOMETHING DAMAGED THE POWER LINES
IN THE AREA WHERE THE POWER IS OUT.

[00:45:08.910]
SOMETHING?

[00:45:09.860]
BOY, THAT COULD BE ANYTHING.

[00:45:11.670]
YES, BUT LET'S NOT GIVE UP.

[00:45:13.690]
REMEMBER, DR. D SAYS THE ANSWER
COULD BE RIGHT IN FRONT OF US.

[00:45:16.430]
LET'S CHECK OUT THE PROBLEM BOARD.

[00:45:19.480]
OKAY, WE KNOW THERE IS A DIFFERENCE

[00:45:21.160]
BETWEEN PARALLEL AND
SERIES CIRCUITS.

[00:45:23.310]
AND WE ALSO KNOW THAT ROOMS

[00:45:25.170]
IN OUR HOMES ARE WIRED
IN PARALLEL CIRCUITS.

[00:45:28.030]
HOUSES IN THE NEIGHBORHOOD ARE
CONNECTED TOGETHER IN PARALLEL,

[00:45:31.340]
MUCH LIKE THE ROOMS IN OUR HOUSES.

[00:45:33.590]
WE NEED TO KNOW SOMETHING
CAN GO WRONG

[00:45:35.520]
WITH POWER LINES AND
CAUSE AN OUTAGE.

[00:45:37.220]
REMEMBER WHAT DR. D SAID
ABOUT SHORT CIRCUITS?

[00:45:40.280]
WE NEED TO KNOW IF THERE IS A
SHORT CIRCUIT ACROSS THE STREET.

[00:45:42.850]
OH, LOOK, A KSNN REPORT.

[00:45:45.420]
MAYBE WE'LL GET ANOTHER CLUE.

[00:45:48.740]
TED TUNE HERE WITH
THIS SPECIAL REPORT.

[00:45:54.090]
WE'VE JUST BEEN INFORMED THAT
I.M. LISSNING HAS A NEW CLUE

[00:45:57.330]
IN THE MYSTERY POWER OUTAGE STORY.

[00:45:59.590]
I.M., ARE YOU THERE?

[00:46:01.430]
TED, WE'VE JUST BEEN INFORMED THAT
AUTHORITIES ARE ON THE LOOKOUT

[00:46:05.720]
FOR SOMEONE NAMED PUBLIC DAMAGE.

[00:46:08.850]
POWER COMPANY OFFICIALS FEEL

[00:46:10.450]
THAT PUBLIC DAMAGE IS
PROBABLY RESPONSIBLE

[00:46:13.780]
FOR THE POWER OUTAGE HERE
IN MR. E'S NEIGHBORHOOD.

[00:46:17.370]
IT IS UNKNOWN AT THIS TIME
WHAT PUBLIC DAMAGE LOOKS LIKE

[00:46:21.790]
OR WHAT HIS OR HER
MOTIVES MIGHT BE.

[00:46:23.570]
YEEOW!

[00:46:25.080]
I.M., ARE YOU THERE?

[00:46:27.010]
WE SEEM TO HAVE LOST CONTACT.

[00:46:28.660]
OH, WAIT.

[00:46:29.600]
TED, THIS JUST IN: I'VE FALLEN
INTO A HOLE IN MR. E'S YARD.

[00:46:35.300]
I'M COVERED WITH MUD
AND GETTING VERY COLD.

[00:46:39.940]
BACK TO YOU.

[00:46:42.400]
THANKS, I.M. THERE YOU HAVE
IT, LADIES AND GENTLEMEN.

[00:46:45.350]
KIDS SCIENCE NEWS NETWORK WILL GO
TO ANY DEPTH TO REPORT ON A STORY.

[00:46:48.870]
AND NOW, WE JOIN OUR
REGULARLY SCHEDULED PROGRAM,

[00:46:51.660]
ALREADY IN PROGRESS.

[00:46:52.700]
I DON'T GET IT.

[00:46:53.490]
WHAT IS PUBLIC DAMAGE?

[00:46:54.810]
REMEMBER THAT E-MAIL THAT WE
RECEIVED FROM THE POWER COMPANY?

[00:47:00.030]
YES.

[00:47:00.120]
WELL, THEY SAID THAT
WE COULD GO ALONG

[00:47:01.480]
WITH THE UTILITY CREW
AND SEE WHAT THEY DO.

[00:47:04.550]
MAYBE THE CREW COULD TELL
US MORE ABOUT PUBLIC DAMAGE.

[00:47:09.540]
GOOD IDEA.

[00:47:10.540]
LET'S GET UP AND GO.

[00:47:13.360]
I'LL SET IT UP.

[00:47:16.330]
HI, CATHERINE.

[00:47:17.100]
HI, BIANCA.

[00:47:17.780]
I'M WARREN WALCK WITH
DOMINION POWER.

[00:47:19.220]
I UNDERSTAND YOU WANT TO LEARN A
LITTLE BIT MORE ABOUT WHAT WE DO,

[00:47:21.680]
AND ABOUT PUBLIC DAMAGE?

[00:47:23.270]
YES, WHAT IS PUBLIC DAMAGE?

[00:47:25.490]
PUBLIC DAMAGE IS WHEN A
PERSON CAUSES A POWER OUTAGE:

[00:47:28.400]
IT MIGHT BE A CAR HITTING A
UTILITY POLE, OR SOMEBODY DIGGING

[00:47:31.960]
IN THEIR BACKYARD HIT
AN UNDERGROUND CABLE,

[00:47:34.230]
OR EVEN VANDALISM.

[00:47:35.430]
SO IF THERE'S PUBLIC
DAMAGE TO A POWER LINE,

[00:47:37.470]
IT'S YOUR JOB TO FIX IT.

[00:47:39.100]
EXACTLY.

[00:47:39.670]
WE HAVE CREWS THAT WILL GO OUT AND
RESTORE SERVICE TO THE CUSTOMER.

[00:47:42.780]
COME ON, LET ME SHOW
YOU SOME THINGS.

[00:47:45.020]
DO YOU KNOW HOW POWER
GETS TO YOUR NEIGHBORHOOD?

[00:47:47.570]
YES, WE KNOW THAT IT IS TRANSMITTED
FROM THE POWER PLANT TO OUR HOMES.

[00:47:53.140]
EXACTLY.

[00:47:53.950]
WHEN THE GENERATOR SPINS IN THE
POWER PLANT, THE VOLTAGE COMES

[00:47:56.810]
OUT AT ABOUT 230,000 VOLTS.

[00:47:59.830]
ISN'T THAT A LOT HIGHER VOLTAGE
THAN WHAT IS USED IN OUR HOMES?

[00:48:02.760]
ABSOLUTELY.

[00:48:04.240]
THEN WHY DOES IT HAVE TO BE
SUCH HIGH VOLTAGE AT THE PLANT?

[00:48:07.410]
ELECTRICITY TRAVELS MUCH EASIER

[00:48:09.530]
OVER LONG DISTANCES
AT A HIGHER VOLTAGE.

[00:48:12.470]
THE HIGH VOLTAGE ELECTRICITY
TRAVELS THROUGH WIRES

[00:48:14.790]
THAT STRING ALL ACROSS THE AREA.

[00:48:17.280]
EVENTUALLY, THESE
HIGH-VOLTAGE POWER LINES GO

[00:48:19.450]
INTO A FENCED-OFF AREA
FULL OF LARGE METAL BOXES,

[00:48:22.750]
FAT WIRES, AND OTHER STUFF.

[00:48:24.660]
THESE AREAS ARE CALLED SUBSTATIONS.

[00:48:27.370]
IN A SUBSTATION, THE VERY
HIGH-VOLTAGE ELECTRICITY IS CHANGED

[00:48:31.310]
INTO LOWER-VOLTAGE ELECTRICITY.

[00:48:33.570]
EVEN THOUGH THE VOLTAGE IS
LOWER, IT IS STILL TOO HIGH

[00:48:35.970]
FOR YOU TO USE IN YOUR HOME.

[00:48:38.000]
IS THERE ANOTHER PLACE WHERE
THE VOLTAGE IS EVEN LOWER?

[00:48:40.800]
THAT'S RIGHT, THERE IS.

[00:48:42.140]
IT'S IN YOUR NEIGHBORHOOD.

[00:48:43.370]
IF YOU LOOK UP ON THE POWER
POLE, YOU'LL SEE A ROUND,

[00:48:45.990]
GRAY, LOOKS LIKE A CAN.

[00:48:47.970]
THAT'S A TRANSFORMER.

[00:48:49.950]
THEY'RE CALLED TRANSFORMERS BECAUSE
THEY TRANSFORM THE ELECTRICITY

[00:48:53.480]
TO JUST THE RIGHT
VOLTAGE FOR YOUR HOME.

[00:48:56.360]
IN OTHER NEIGHBORHOODS,
THE WIRES ARE UNDERGROUND.

[00:48:59.570]
IN THAT CASE, THE
TRANSFORMER IS A BIG GREEN BOX.

[00:49:03.080]
WHAT IS THE VOLTAGE
USED FOR OUR HOMES?

[00:49:05.520]
EVENTUALLY, THE VOLTAGE IS
STEPPED DOWN TO 240 VOLTS

[00:49:08.770]
FOR YOUR LARGE APPLIANCES -- THAT
WOULD BE LIKE YOUR AIR CONDITIONER

[00:49:11.540]
AND YOUR CLOTHES DRYER
-- AND THEN 120 VOLTS,

[00:49:14.950]
AND THAT WOULD RUN
LIKE YOUR HAIR DRYER,

[00:49:16.560]
OR YOUR MICROWAVE, OR YOUR TOASTER.

[00:49:17.880]
IS THERE A WAY THAT WE CAN
MEASURE HOW MUCH ENERGY IS USED

[00:49:21.250]
IN OUR HOMES?

[00:49:22.370]
YES, THERE'S A METER ON THE SIDE

[00:49:23.690]
OF YOUR HOUSE CALLED
A KILOWATT HOUR METER.

[00:49:26.500]
WHAT IS A KILOWATT HOUR?

[00:49:28.280]
A KILOWATT HOUR IS A
MEASUREMENT OF ENERGY.

[00:49:30.990]
KILO MEANS "1,000," SO THAT'S
1,000 WATTS: A KILOWATT.

[00:49:36.040]
A TOASTER IS A ONE-KILOWATT DEVICE.

[00:49:38.580]
IF IT WERE RUNNING FOR ONE HOUR,

[00:49:40.340]
IT WOULD USE A KILOWATT
HOUR OF ENERGY.

[00:49:42.780]
YOU CAN FIGURE OUT HOW MUCH
ENERGY AN APPLIANCE WILL USE.

[00:49:46.440]
YOU JUST TAKE THE READING OF
THE APPLIANCE IN KILOWATTS,

[00:49:49.240]
THE TIME IT IS ON
CONTINUOUSLY, AND MULTIPLY THEM.

[00:49:53.160]
IF A MICROWAVE USED ONE KILOWATT
OF POWER PER HOUR FOR THREE HOURS,

[00:49:58.240]
THAT WOULD EQUAL THREE
KILOWATT HOURS.

[00:50:00.620]
IF WE HAD A THREE-KILOWATT
DEVICE THAT RAN FOR ONE HOUR,

[00:50:03.860]
WOULD IT BE T

The Open Video Project is managed at the Interaction Design Laboratory,
at the School of Information and Library Science, University of North Carolina at Chapel Hill