>>> PRESENTATION OF SCIENCE TREK
ON IDAHO PUBLIC TELEVISION IS

MADE POSSIBLE THROUGH THE
GENEROUS SUPPORT OF THE LAURA

MOORE CUNNINGHAM FOUNDATION,
COMMITTED TO FULFILLING THE

MOORE FAMILY LEGACY OF BUILDING
THE GREAT STATE OF IDAHO.

>>> THE EARTH IS OUR HOME, BUT
IT'S MADE UP OF MANY COMPLEX

SYSTEMS WORKING TOGETHER TO KEEP
US ALIVE.

FIND OUT MORE ABOUT THE EARTH.

STAY TUNED.

SCIENCE TREK IS NEXT.

>>> HI, I'M JOAN CARTAN-HANSEN,
AND WELCOME TO SCIENCE TREK, AND

WELCOME TO BOISE STATE
UNIVERSITY'S EARTH, SCIENCE,

RESEARCH LAB.

WE'RE HERE TO ANSWER YOUR
QUESTIONS ABOUT THE EARTH, BUT

BEFORE WE DO, LET'S LEARN A BIT
MORE.

>> LET'S SEE IF WE CAN KEEP IT
UP IN THE AIR, AND WHO FOR THE

LONGEST.

>> OK.

>> DID YOU KNOW THE EARTH IS
93 MILLION MILES FROM THE SUN?

THE EARTH IS THE THIRD PLANET
FROM THE SUN.

THE EARTH'S ORBIT IS MORE LIKE
AN ELLIPSE RATHER THAN A PERFECT

CIRCLE.

THE EARTH SPINS ON AN AXIS, AND
AN IMAGINARY LINE THAT GOES FROM

POLE TO POLE.

THE EARTH IS AT A TILT, IT'S THE
TILT THAT GIVES US OUR SEASONS

AS THE EARTH TRAVELS AROUND THE
SUN.

WHEN THE NORTHERN HEMISPHERE
TILTS AWAY FROM THE SUN, YOU

HAVE WINTER.

AND AS THE NORTHERN HEMISPHERE
TILTS TOWARDS THE SUN, WE GET

SUMMER.

AND BECAUSE THE EARTH IS
SPINNING ON ITS AXIS, ONE SIDE

OF THE PLANET FACES THE SUN AND
THE OTHER IS IN THE SHAD OV,

THAT'S WHAT GIVES US DAY AND
NIGHT.

>> DID YOU KNOW THAT OXYGEN ONLY
MAKES UP 20% OF OUR AIR?

>> THE EARTH IS COVERED BY A
BLANKET OF GASES KNOWN AS THE

SPHERE.

THE TROPOSPHERE IS THE LOWEST
LEVEL, THAT'S WHERE YOU WILL

FIND THE AIR WE BREATHE.

THE AIR IS 20% OXYGEN AND 70%
NITROGEN, AND THE REST IS MADE

UP OF OTHER GASES.

ALL OF THE EARTH'S WEATHER
HAPPENS IN THE TROPOSPHERE.

THE NEXT LAYER IS THE
STRATOSPHERE.

THIS LAYER CONTAINS OZONE, A GAS
THAT PROTECTS US FROM THE

HARMFUL ULTRAVIOLET RAYS OF THE
SUN.

AFTER THAT, IS THE MESOSPHERE.

THIS IS THE LAYER WHERE
METEORITES USUALLY BURN UP FROM

SPACE CREATING SHOOTING STARS.

THEN THERE IS THE THERMO SPHERE,
AND FINALLY THE EXOSPHERE.

THIS IS THE OUTO MOST LAYER AT
THE EDGE OF SPACE.

>> LET ME PLAY!

>> NO WAY.

>> SO, DID YOU KNOW THAT THE
EARTH'S CRUST IS ALWAYS MOVING?

>> THE EARTH HAS FOUR MAIN
LAYERS.

AT THE CENTER IS AN EXTREMELY
HOT CORE.

THE CORE IS MADE UP OF TWO
REGIONS.

THE INNER CORE IS MADE UP OF
SOLID, IRON, AND NICKEL.

THE OUTER CORE IS MADE UP OF
LIQUID IRON.

THEY THINK THAT THE CIRCULATION
OF THAT LIQUID CAUSES THE

MAGNETIC FIELD AROUND THE EARTH.

THE NEXT LAYER IS THE MANTLE,
AND THEN THE OUTER LAYER, THE

LAYER WE LIVE ON, IS KNOWN AS
THE CRUST.

THE CRUST IS ABOUT FOUR TO
40 MILES THICK AND MAKES UP LESS

THAN 1% OF THE EARTH'S MASS.

IT'S BROKEN UP INTO PIECES KNOWN
AS TECTONIC PLATES.

TECTONIC PLATES ARE PUSHED AND
PULLED AROUND BY THE SLOW AND

STEADY MOVEMENT OF THE
UNDERLYING ROCK.

AS THE PLATES MOVE, STRESSES
BUILD UP.

EARTHQUAKES HAPPEN WHEN THE
STRESSES GROW BIG ENOUGH THAT

THE PLATES SLIDE PAST ONE
ANOTHER QUICKLY, AND WE FEEL

THAT SHAKING.

MOST VOLCANOS APPEAR ALONG PLATE
BOUNDARIES.

LOTS OF THINGS CAN CHANGE THE
EARTH'S SURFACE.

SOME HAPPENS QUICKLY FROM STRONG
THINGS LIKE EARTHQUAKES AND

VOLCANOES.

OTHERS HAPPEN OVER PERIODS OF
TIME BECAUSE OF PROCESSES LIKE

EROSION FROM WIND OR WATER.

YOU CAN SEE PATTERNS IN ROCK
FORMATIONS AND FOSSILS IN ROCK

LAYERS THAT SHOW CHANGES IN THE
EARTH'S SURFACE OVER TIME.

HUMANS CHANGE THE LOOK OF
EARTH'S SURFACE, TOO.

BUILDINGS, FARMS, AND MINES ARE
A FEW WAYS WE HAVE CHANGED THE

LOOK OF THE EARTH.

DID YOU KNOW THAT MOST OF THE
EARTH'S SURFACE IS COVERED WITH

WATER?

>> 70% OF THE EARTH'S SURFACE IS
COVERED BY OCEAN.

ONLY .008% OF THE EARTH'S FRESH
WATER IS FOUND IN LAKES, RIVERS,

AND STREAMS.

THAT'S THE WATER THAT WE NEED TO
LIVE.

SO, WHEN YOU THINK ABOUT THE
EARTH, THINK ABOUT THE SYSTEMS

THAT MAKE UP THE PLANET.

THE GEOSPHERE, THE SOIL,
SEDIMENTS AND SOLID AND MOLTEN

ROCK.

THE HYDROSPHERE, THE WATER ON
EARTH.

THE ATMOSPHERE, THE LEVELS OF
AIR AND GASES AROUND THE EARTH,

AND THE BIOSPHERE, ALL THE
ECO-SYSTEMS AND LIVING THINGS ON

EARTH.

>> THAT'S A LOT TO THINK ABOUT.

>> PLEASE LET ME PLAY!

>> YOU WILL GET YOUR, GO AND GET
YOUR OWN BALL.

>> OK.

YOU ARE GOING TO PLAY THAT LOOKS
LIKE THIS, I AM GOING TO PLAY

WITH ONE THAT LOOKS LIKE THE
SUN.

>> WHAT IS THAT ALL ABOUT?

YOU KNOW.

>> AND JOINING ME NOW TO ANSWER
YOUR QUESTIONS ABOUT THE EARTH

ARE VIRGINIA GILLERMAN, A
GEOLOGIST WITH THE IDAHO

GEOLOGICAL SURVEY, AND JEFFERY
JOHNSON, ASSISTANT RESEARCH

PROFESSOR OF GEOPHYSICS AT BOISE
STATE UNIVERSITY.

THANK YOU FOR JOINING US.

>> THANK YOU VERY MUCH.

>> THANK YOU.

>> THIS IS GOING TO BE FUN.

>> LET'S GO TO YOUR QUESTIONS.

>> HI, MY NAME IS JEFF, AND I GO
TO KAMIAH ELEMENTARY SCHOOL IN

KAMIAH, IDAHO, AND MY QUESTION
IS -- WHAT MAKES THE EARTH

ROTATE?

>> THE EARTH ROTATES BECAUSE
IT'S ALWAYS ROTATED, AND THAT'S,

THAT'S REALLY A PRETTY POOR
ANSWER.

BUT, IT IS INTERESTING TO NOTE
THAT THE EARTH IS ROTATING ABOUT

THE SAME RATE THAT IT IS NOW, AS
IT DID WHEN THE EARTH FORMED

4.6 BILLION YEARS AGO.

THE FACT OF THE MATTER IS, IT'S
SPINNING LIKE A TOP, AND THERE

IS NOTHING OUT THERE, NO
FRICTION THAT'S SLOWING IT DOWN,

AND IT WILL CONTINUE TO SPIN
UNTIL THE EARTH MAY BE BILLIONS,

TRILLIONS OF YEARS FROM NOW,
IMPACTS WITH ANOTHER BODY.

>> HI, I AM BILLY, AND I AM FROM
[INAUDIBLE] CHARTER SCHOOL, AND

MY QUESTION IS -- WHAT ARE
TECTONIC PLATES?

>> TECTONIC PLATES, BILLY, ARE
WHAT GEOLOGISTS CALL THE RIGID

LAYERS OF ROCK, WHICH FLOAT ON A
HOTTER AND MORE FLUID

SEMI-LIQUID ROCK UNDERNEATH.

THE TECTONIC PLATES ARE
CONSTANTLY IN MOTION, AND WHEN

ONE OF THEM DIVES UNDER THE
OTHER, LIKE ON, ON THE, THE

EASTERN, OR WESTERN COAST OF
SOUTH AMERICA, THEY CAN FORM

MOUNTAIN RANGES LIKE THE ANDES
AND VOLCANOES LIKE ECUADOR OR

SIMILAR THINGS ARE HAPPENING IN
JAPAN.

SO, IT'S, IT'S THE BOUNDARIES
BETWEEN THESE TECTONIC PLATES

THAT CREATES SOME OF OUR MOST
INTERESTING GEOLOGY.

>> AND ONE OF THE COOL THINGS
ABOUT TECTONIC PLATES IS JUST

HOW FAST THAT THEY MOVE.

TECTONIC PLATES ARE MOVING
CONSTANTLY, BUT YOU AND I, WE

CANNOT FEEL THEM.

THEY MOVE AT THE SAME SPEED AS
YOUR FINGERNAILS GROW.

>> JAMISON WOULD LIKE TO KNOW,
HOW BIG IS THE EARTH?

>> THE EARTH HAS A RADIUS OF
6,371 KILOMETERS ON AVERAGE.

THIS IS SOME 4,000 MILES IN
TERMS OF THE RADIUS.

HOW FAR IS THAT?

THAT'S ABOUT THE DISTANCE FROM
IDAHO TO NEW YORK AND BACK, AND

SO IT'S A CONSIDERABLE SIZE.

ONE THING THAT YOU MAY NOT BE
AWARE OF IS THAT THE EARTH HAS A

RADIUS THAT IS, THAT IS A LITTLE
BIT BIGGER AT THE EQUATORS THAN

AT THE POLES SO, OF THE EARTH AS
BEING A SPHERE THAT'S SLIGHTLY

SQUASHED.

>> I AM ADDISON, AND MY QUESTION
IS, WILL THE EARTH CONTINENTS

EVER MEET AGAIN?

>> THE EDGES OF THE CONTINENTS
MEET, THEY MEET THE OCEAN

PLATES, AND SOMETIMES, THEY MEET
OTHER CONTINENTAL PLATES LIKE IN

THE HIMALAYAS, BUT OVER THE LAST
COUPLE OF BILLION YEARS,

GEOLOGISTS ARE FINDING OUT, THE
EARTH'S CONTINENTS AND PLATES

HAVE MOVED TOGETHER AND THEN
BEEN DRIVEN APART SEVERAL TIMES.

SO, WE FORMED SUPER CONTINENTS
LIKE RODINIA AND PANCIA, WHERE

THE CONTINENTAL MASSES, THE LAND
THAT YOU SEE THAT HAS ROCKS THAT

HAVE MORE SILICON AND ALUMINUM
AND SANDSTONE AREAS, THOSE

CONTINENTAL AREAS HAVE BEEN
PUSHED TOGETHER INTO THE SUPER

COULD NOT NENTSZ, AND OVER TIME
THOSE WILL BREAK APART AGAIN,

SORT OF LIKE BILLIARD BALLS, YOU
KNOW.

HITTING EACH OTHER AND THEN
BOUNCING OFF EACH OTHER.

SO, THEY WILL MEET AGAIN, AND
THEY WILL BREAK APART AGAIN.

IT MAY TAKE A FEW MILLION YEARS.

>> AND IN INDIA AND ASIA RIGHT
NOW ARE COLLIDING WITH ONE

ANOTHER, BUT IT'S A SLOW MOTION
COLLISION.

THOSE TWO CONTINENTS ARE COMING
TOGETHER AT A RATE OF ONLY A FEW

INCHES A YEAR, AND THEY ARE
CAUSING THE CONTINUING UPLIFT IN

GROWTH OF THE HIMALAYA
MOUNTAINS.

>> HARRIS WOULD LIKE TO KNOW,
HOW WAS THE EARTH FORMED?

>> HARRIS, THE EARTH WAS FORMED
A LONG, LONG TIME AGO,

4.6 BILLION YEARS AGO, THE EARTH
ACCUMULATED FROM INTERSTELLAR

GASES AND DEBRIS AND ACCUMULATED
AND GREW INTO THE BLOB THAT WE

LIVE ON TODAY.

>> ALLEY WOULD LIKE TO KNOW, HOW
DID GRAVITY GET TO EARTH AND WHO

OR WHAT CREATED IT?

>> GRAVITY IS A FUNDAMENTAL
FORCE THAT EXISTS ANY TIME THAT

YOU HAVE MASS.

SO, WE HAVE GRAVITY ASSOCIATED
WITH OUR OWN HUMAN BODIES, BUT

THE EARTH'S MASS IS SO MUCH
LARGER, THAT THE GRAVITATIONAL

FORCE IS VERY MUCH NOTICEABLE.

THIS IS WHY WE DON'T FLOAT OFF
INTO SPACE.

SO, WE HAVE GRAVITY BECAUSE THE
EARTH IS VERY BIG AND MASSIVE.

OTHER PLANETS ALSO HAVE GRAVITY,
AND GRAVITY CAN EITHER BE

GREATER OR SMALLER, DEPENDING
UPON HOW BIG THE PLANETS ARE.

SO, IF YOU LIVE ON ANOTHER
PLANET THAT'S BIGGER, YOU WILL

HAVE A GREATER FORCE OF GRAVITY,
AND YOU WILL WEIGH HEAVIER.

>> HI, I'M KELLEN, AND MY
QUESTION IS -- WHAT PURPOSE DO

THE LAYERS OF THE ATMOSPHERE
SERVE?

>> WELL, KELLEN, THE ATMOSPHERE
IS REALLY CRITICAL FOR US HUMAN

BEINGS BECAUSE IT PROVIDES THE
OXYGEN THAT WE NEED TO BREATHE

AND TO LIVE FROM, AND IT ALSO
PROVIDES CARBON DIOXIDE, WHICH

PLANTS BREATHE AND USE IN PHOTO
SYNTHESIS, AND IT HAS OZONE,

THAT HELP TO PROTECT US FROM THE
SUN'S HARMFUL RADIATION.

SO, WE WOULD NOT BE HERE WITHOUT
THE ATMOSPHERE.

>> I WAS GOING TO ADD THAT THE
WEATHER IS HAPPENING IN OUR

ATMOSPHERE, AS WELL.

>> WEATHER, OF COURSE.

THAT'S A REALLY IMPORTANT
FUNCTION.

>> YOU MAY FEEL LIKE YOU ARE
STANDING STILL, BUT AS THE EARTH

SPINS, YOU ARE MOVING FAST,
DEPENDING ON WHERE YOU ARE ON

THE GLOBE, YOU COULD BE SPINNING
AT OVER 1,000 MILES PER HOUR,

AND WE ALL TRAVEL AT 67,000
MILES PER HOUR AS THE EARTH

MOVES AROUND THE SUN.

>> HI, MY NAME IS ZOE, AND MY
QUESTION IS -- HOW DOES THE

EARTH'S ATMOSPHERE COMPARE TO
OTHER PLANETS?

>> EARTH'S ATMOSPHERE IS THE
BEST ATMOSPHERE THAT WE KNOW OF

FOR SUSTAINING LIFE.

NOW, OTHER PLANETS WITHIN OUR
SOLAR SYSTEM ALSO HAVE

ATMOSPHERES.

MOST OF THEM ARE MUCH, MUCH
THINNER THAN THE EARTH'S

ATMOSPHERE, AND NONE OF THEM
HAVE OXYGEN, WHICH IS NECESSARY

FOR LIFE.

ONE OF THE SOLAR SYSTEMS PLANETS
THAT HAS A THICK ATMOSPHERE IS

VENUS, AND VENUS HAS LOTS AND
LOTS OF CARBON DIOXIDE, AND AS

FAR AS WE KNOW, THIS IS NOT A
GAS THAT'S VERY GOOD FOR MOST

TYPES OF LIFE FORMS.

>> KYLE WOULD LIKE TO KNOW IS IT
POSSIBLE TO LIVE ON ANOTHER

PLANET?

>> IT'S NOT POSSIBLE FOR HUMANS,
LIKE WE ARE, TO LIVE ON ANY OF

THE OTHER PLANETS THAT WE KNOW
ABOUT.

CERTAINLY NOT IN THIS SOLAR
SYSTEM.

THEY DON'T HAVE THE RIGHT AMOUNT
OF OXYGEN IN THE ATMOSPHERE.

SOME OF THEM ARE WAY TOO HOT.

SEVERAL HUNDRED DEGREES EVERY
DAY.

OR WAY TOO COLD.

AND, AND OUR LIFE, OUR, OUR
HUMANS AND OUR ANIMALS AND OUR

PLANTS HAVE EVOLVED UNDER THE
SPECIAL CIRCUMSTANCES ON EARTH.

SO, WITHOUT EXTRAORDINARY
MEASURES AS IN A SPACE STATION

OR SUITS, WE CANNOT LIVE ON
OTHER PLANETS IN THE SOLAR

SYSTEM.

>> I AM INDY, AND MY QUESTION IS
-- HOW DOES THE ATMOSPHERE KEEP

IN OXYGEN?

>> WELL, INDY, THE SPHERE HAS A
VERY IMPORTANT ROLE IN KEEPING

IN THE OXYGEN.

SOME OF THAT IS DUE TO CARBON
DIOXIDE AND OTHER GASES IN THE

ATMOSPHERE.

AND, AND I BELIEVE THAT SOME OF
IT IS SIMPLY DUE TO GRAVITY

BECAUSE GRAVITY STILL WOULD
EXERT SOME PULL ON, ON EVEN

GASES, IS THAT CORRECT, JEFF?

>> GRAVITY, ULTIMATELY, KEEPS
THE ATMOSPHERE NEXT TO THE

EARTH, BUT, IT'S IMPORTANT TO
NOTE THAT WE ARE LOSING OXYGEN

TO, TO, DUE TO, DUE TO TRAVEL
OUTSIDE OF OUR ATMOSPHERE.

AND, AND AS WELL AS BY
ABSORPTION OF OXYGEN IN OUR

ROCKS.

SO, THERE IS A CONSTANT BALANCE
BETWEEN PRODUCTION OF OXYGEN

FROM PLANTS AND LOSS OF OXYGEN
DUE TO ESCAPE FROM THE PLANET,

AS WELL AS THE PROCESSES WHICH
LOCK UP THAT OXYGEN IN OUR

ROCKS.

>> AND HI.

MY NAME IS CHLOE, AND I GO TO
HILLCREST ELEMENTARY SCHOOL.

HOW DOES THE VOLCANO SHOOT OUT
LAVA?

>> OH, I GET THIS ONE, CHLOE.

I LOVE TO STUDY VOLCANOES, AND I
STUDY HOW VOLCANOES PRODUCE LAVA

AND HOW THAT LAVA GETS EJECTED
FROM A VOLCANIC VENT.

SO, REALLY, THERE IS ONE QUICK
ANSWER, AND THAT IS VOLCANIC

GASES DRIVE EXPLOSIONS, AND
THOSE GASES CAN BE STEAM, CARBON

DIOXIDE, OR SULFUR DIOXIDE, BUT
PRESSURIZED GASES BLOW MATERIAL

OUT OF A VOLCANIC VENT WITH MORE
ENERGY AND MORE POWER THAN YOU

CAN EVEN IMAGINE.

>> MY NAME IS SOPHIE AND MY
QUESTION IS, HOW DO HOT SPOTS

MOVE?

>> SOPHIE HOT SPOTS DON'T REALLY
MOVE.

IT'S, ACTUALLY, THE TECTONIC
PLATES THAT MOVE OVER THE HOT

SPOTS, SO A HOT SPOT LOOKS LIKE
A PENCIL, THAT EXTENDS DEEP INTO

THE EARTH.

AND AS THE PLATE MOVES OVER IT,
IT CREATES AN APPARENT HOT SPOT

TRACK.

AND FOR EXAMPLE, THE YELLOWSTONE
HOT SPOT IS CURRENTLY UNDER

YELLOWSTONE NATIONAL PARK.

BUT 15 MILLION YEARS AGO, THE
CONTINENT WAS SITUATED SUCH THAT

HOT SPOT WAS ABOUT WHERE THE
JUNCTION OF OREGON, IDAHO, AND

NEVADA IS, IS TODAY.

WE CAN TRACK THE MOVEMENT OF THE
PLATE OVER THAT HOT SPOT BY

LOOKING AT AGES OF ROCKS, THE
PARTICULAR TYPE OF VOLCANIC

ROCK, ALONG THAT, THAT, THAT HOT
SPOT TRACK.

>> HI, I AM OSCAR, AND I WAS
WONDERING HOW COME YELLOWSTONE

IS SO GEE LOGICALLY ACTIVE AND
WHY THERE IS NO OTHER PLACE IN

THE WORLD LIKE IT.

>> YELLOWSTONE IS VERY ACTIVE.

WE THINK IT'S ACTIVE BECAUSE WE
CAN SEE IT TODAY.

BUT, THERE ARE OTHER PLACES IN
THE EARTH THAT ARE SIMILAR TO

YELLOWSTONE THAT HAVE SIMILAR
ROCKS, FOR EXAMPLE, THE, THE

VOLCANIC ZONE IN NEW ZEALAND,
WHICH IS ALSO UNDER LANE BY WHAT

GEOLOGISTS WHERE THERE IS A
LARGE MASS OF LIQUID ROCK OR

MAGMA THAT IS HIGH IN SILICON
AND ALUMINUM.

AND, AND IN THAT CASE, ALSO,
LIKE YELLOWSTONE, THE, THE HOT

MAGMA CHAMBER HAS HEATED THE
GROUNDWATER AND PRODUCED

GEYSERS, HOT POOLS, MUD POTS,
AND SIMILAR FEATURES THAT IF YOU

VISIT NEW ZEALAND, YOU CAN WALK
THROUGH.

SO, YELLOWSTONE IS ONE OF THE
PLACES THAT IS VOLCANOICALLY AND

GEOTHEY REMEMBERALLY ACTIVE
RIGHT NOW.

THERE HAVE BEEN OTHER PLACES
LIKE IT IN THE PAST, AND THERE

IS A FEW OTHER PLACES LIKE IT IN
THE WORLD TODAY.

>> I JUST LIKE TO ADD THAT
YELLOWSTONE IS SPECIAL IN THAT

IT HAS THE MOST GEYSERS IN THE
ENTIRE WORLD.

IN FACT, 50% OF EARTH'S GEYSERS
HAPPEN TO BE IN YELLOWSTONE.

IT IS WONDERFUL.

IT'S IN OUR BACKYARD, AND I AM
VERY PROUD TO BE LIVING NOT SO

FAR AWAY FROM YELLOWSTONE.

>> THE FIELD OF STUDY THAT DEALS
WITH THE REPRESENTATION AND

MEASUREMENT OF THE EARTH IS
GEOCITY.

IT IS A SCIENCE THAT GOES WAY
BACK.

>> A LONG TIME AGO IN EGYPT, A
MAN FIGURE OUT WHEN THE SUN WAS

ABOVE ONE CITY, YOU COULD STAND
AT A NEARBY CITY TO THE NORTH

AND MEASURE THE ANGLE OF THE
SHADOW SAYS AND MULTIPLY THAT BY

THE DISTANCE TO GET THE DISTANCE
AROUND THE ENTIRE EARTH.

WITH THAT, THE SCIENCE OF
GEODESY WAS BORN.

IT DEALS WITH THE MEASUREMENT
AND REPRESENTATION OF THE EARTH,

OR TO PUT IT MORE SIMPLY, THE
SCIENCE OF WHERE THINGS ARE AND

JUST AS IMPORTANTLY, WHERE THEY
HAVE BEEN AND WHERE THEY ARE

GOING.

6 THROUGH GEODESY, WE LEARN THE
SIZE AND SHAPE OF THE EARTH, THE

DIRECTION OF THE ROTATION, AND
THE DISTANCE FROM THE SUN, AND

MORE.

WE THROUGH TRIANGULATION, WE CAN
CREATE MAPS OF COUNTRIES, AND

EVEN FIGURED OUT THE EARTH IS
NOT A PERFECT SPHERE, AND AFTER

SOME ARGUMENTS AND EXPEDITIONS
TO PERU, WE MEASURED THAT IT'S

JUST A BIT THICKER IN THE
MIDDLE.

BUILDING ON THIS INFORMATION, WE
FOUND TONS OF PRACTICAL USES FOR

GEODESY.

USUALLY STARS AS A REFERENCE
POINT, AND ACCURATE WATCHES, WE

COULD RELIABLY DETERMINE
LATITUDE AND LONGITUDE SO SHIPS

COULD CROSS OCEANS TO GET TO
WHERE THEY NEEDED.

THE EXPLORERS VISITED
UNCHARTERED REGIONS, AND MAPPED

THEM AND FOUND THE TALLEST
MOUNTAIN IN THE WORLD.

LATER, ENGINEERS BUILT RAILROADS
TO GET US TO THESE PLACES.

WITH THE SAME REFERENCE SURFACE,
RAIL TUNNELS COULD BE STARTED ON

BOTH SIDES OF THE MOUNTAIN, AND
SOMEHOW MEET IN THE MIDDLE.

LIFE WAS GOOD.

ONCE WE INVENTED RADIO
TELESCOPES AND SATELLITES,

THINGS GOT EVEN BETTER.

WHEN SCIENTISTS USED A BUNCH OF
SMALL RADIO DISHES LIKE ONE BIG

ONE TO LOOK, SOMEBODY GOT THE
IDEA YOU COULD USE THESE

MEASUREMENTS TO DETERMINE VERY
ACCURATELY THE DISTANCE BETWEEN

THE TELESCOPES, AND NOW WE CAN
LOOK AT THE MOVEMENT OF THE

EARTH'S CHANGES, AND HOW THE
EARTH TRAVELS ON ITS AXIS.

SATELLITES BECAME VERY IMPORTANT
BY ANALYZING THEIR ORBITS, WE

CAN LEARN ABOUT OUR PLANET'S
CHANGING SIZE AND SHAPE AND

GRAVITY, AND BY MAKING LASER
MEASUREMENTS, WE CAN LOOK AT

CHANGES IN THE HEIGHT OF THE
OCEANS AND ICE SHEETS TO HOW THE

TIETH -- TIETS -- TIDES WORK, IS
A GEODESY HAS A HUGE IMPACT ON

OUR LIVES AND ALL BECAUSE
SOMEBODY A LONG TIME AGO DECIDED

TO LOOK DOWN A WELL.

>> I AM FENA, AND MY QUESTION IS
-- WHY WAS THERE VOLCANIC

ACTIVITY IN IDAHO'S GEOLOGIC
HISTORY BUT THERE ARE NOT ANY

VOLCANOES IN IDAHO NOW?

>> THERE HAVE BEEN PERIODS IN
THE PAST, NOTABLY, ABOUT

2 MILLION YEARS AGO, WHEN THE
VOLCANOES OF THE SNAKE RIVER

PLAIN WERE POPPING UP ALL OVER
THE PLACE.

15 MILLION YEARS AGO, WHEN THE
COLUMBIA RIVER, BASALTS POURED

OUT AND FLOWED TO THE PACIFIC
OCEAN, AND ABOUT 45 MILLION

YEARS AGO, WHEN THE CHALLIS
VOLCANIC EPISODE OCCURRED.

SO, THERE'S BEEN TIMES WHEN IT'S
BEEN MUCH MORE ACTIVE THAN IT IS

RIGHT NOW.

BUT, YOU NEVER KNOW.

MAYBE WE'LL GET A, A BIG
VOLCANIC ERUPTION TOMORROW.

>> YOU KNOW, I WOULD NOT LOSE
SLEEP OVER THE IDEA OF A BIG

VOLCANIC ERUPTION TOMORROW.

BUT, IT IS IMPORTANT TO NOTE
THAT IDAHO DOES HAVE RECENT

VOLCANIC ACTIVITY, AS EARLY AS,
AS RECENT AS 2000 YEARS AGO,

THERE WERE LAVAS THAT ERUPTED
FROM CRATERS OF THE MOON

NATIONAL MONUMENT THAT HAS VERY,
VERY FRESH LAVA FLOWS.

AND 2000 YEARS AGO IS REALLY A
BLINK OF THE EYE IN TERMS OF THE

GEOLOGIC HISTORY.

>> GABBY WOULD LIKE TO KNOW HOW
DO WE GET EARTHQUAKES?

>> EARTHQUAKES HAPPEN WHEN ROCKS
BREAK VERY, VERY QUICKLY.

WHEN THAT HAPPENS, THE EARTH
MOVES VERY RAPIDLY, AND

GENERATES SEISMIC WAVES, WHICH
WE CAN RECORD WITH, WITH

DELICATE AND HIGH FIDELITY
INSTRUMENTATION CALLED

SIZEOMETERS.

THAT IS NOTHING MORE THAN AN
INSTRUMENT THAT RECORDS THE

SHAKING OF THE GROUND WITH MUCH
MORE SENSITIVITY THAN HUMANS

CAN.

>> I AM AALIYAH AND I HAVE A
QUESTION, WHY DOES CALIFORNIA

HAVE SO MANY EARTHQUAKES AND
IDAHO HAS SO FEW.

>> YOU ARE ASKING WHY DOES IDAHO
NOT HAVE MANNY EARTHQUAKES AS

CALIFORNIA.

IT'S FOR THE SIMPLE REASON THAT
IDAHO IS LOCATED IN THE INTERIOR

OF A CONTINENT.

CALIFORNIA IS RIGHT ON THE VERY
EDGE OF WHERE NORTH AMERICA AND

PACIFIC TECTONIC PLATES MEET.

AND IT JUST SO HAPPENS THAT MOST
OF EARTH'S EARTHQUAKES HAPPEN

ALONG THESE BOUNDARIES.

THAT IS NOT TO SAY THAT IDAHO
DOESN'T HAVE ANY EARTHQUAKES OR

WON'T HAVE EARTHQUAKES IN THE
FUTURE, BUT THE NUMBER OF

EARTHQUAKES IN IDAHO IS FAR LESS
THAN IT IS IN, SAY, CALIFORNIA,

AND THE SIZE OF THE EARTHQUAKES
THAT OCCUR HERE, ARE GENERALLY

MUCH SMALLER.

THE MOST RECENT, LARGEST
EARTHQUAKES TO HAVE OCCURRED IN

IDAHO HAPPENED IN 1983.

AND IT WAS A MAGNITUDE OF 7.3
EARTHQUAKE.

BUT THEY HAPPEN VERY
INFREQUENTLY.

>> CARA ASKS, WHY DOES THE EARTH
MOVE BUT WE DON'T FEEL IT MOVE?

>> THE EARTH MOVES, AND IT MOVES
OVER ALL SORTS OF TIME SCALES,

AND IT MOVES IN VERY INTERESTING
FASHIONS.

WE DO EXPERIENCE EARTH MOVEMENTS
WHEN EARTHQUAKES OCCUR, AND THAT

IS WHEN, WHEN SUDDEN BREAKAGE OF
ROCKS CAUSE A SEISMIC WAVE TO

PROPGATE AND SHAKE IT, BUILDINGS
CAN BE KNOCKED OVER, AND THOSE

MOVEMENTS CAN BE VERY, VERY
INTENSE.

NOW, THE EARTH ALSO MOVES VERY
SLOWLY DUE TO PLATE TECTONIC

MOVEMENTS.

THOSE MOVEMENTS ARE SO VERY
SLOW, THAT MOST OF US WILL NEVER

SENSE THEM.

THOSE PLATE TECTONIC MOVEMENTS
OCCUR AT RATES OF ONLY A FEW

INCHES PER YEAR.

VERY, VERY SLOW.

>> AND, OF COURSE, THE EARTH IS
MOVING, SIMPLY BY ROTATING EACH

DAY.

BUT, IT HAPPENS ON SUCH A LARGE
MASS, AND AT SUCH A, A SLOW RATE

THAT WE DON'T FEEL IT.

>> HI, I AM JENNA, AND I AM PART
OF ANSWER -- ANTHONY CHARTER

SCHOOL, AND MY QUESTION IS WHY
IS THE SKY BLUE?

>> THE SKY IS THE BLUE BECAUSE
THE SUN WHEN RADIATES OUR

SUNLIGHT IN THE FORM OF LIGHT,
WHICH COMPRISES ALL COLORS OF

THE RAINBOW, INTERACTS WITH THE
SPHERE.

OUR ATMOSPHERE HAS OXYGEN IN IT
WHEN SCATTERS THE BLUE PORTION

OF THE VISIBLE LIGHT, AND THAT
THAT SCATTERED ENERGY COMES

DOWN, AND WE CAN SEE IT WITH OUR
EYES.

IF YOU WERE TO LOOK AT THE SUN
OUTSIDE OF THE SPHERE, IT WOULD

LOOK WHITE.

>> DEVON ASKS, HOW DID THE EARTH
GET ITS NAME?

>> I HAD TO LOOK THIS ONE UP.

AND FROM WHAT I COULD READ, THE
NAME COMES FROM AN OLD ENGLISH

WORD, CLOSE TO EARTHA, I'M NOT
SURE I'M PRONOUNCING IT RIGHT,

BUT THE TERM GOES BACK AT LEAST
OVER 1,000 YEARS, PROBABLY AT

LEAST 1500 YEARS THAT WE CAN
TRACE IT THROUGH THE LANGUAGES,

INCLUDING OLD AND MIDDLE ENGLISH
FROM SIMILAR SOUNDING WORDS.

THERE WAS, I BELIEVE, A, A
MYTHOLOGICAL GOD OF THE EARTH,

WITH A SOMEWHAT SIMILAR NAME,
BUT, EARLIER THAN THAT, I'M NOT

REAL SURE.

IT IS A GOOD QUESTION FOR A
LINGUISTICS' EXPERT.

>> AND THE EARTH IS, INDEED, THE
ONLY PLANET IN THE SOLAR SYSTEM

THAT HAS A NAME THAT DOES NOT
COME FROM GREEK OR ROMAN

MYTHOLOGY.

>> MY QUESTION IS, HOW DOES THE
MAGNETIC FIELD CHANGE FROM NORTH

TO SOUTH?

>> THIS QUESTION IS A
FUNDAMENTALLY IMPORTANT QUESTION

FOR WHICH THERE IS NO CONSENSUS
ANSWER.

WHAT WE DO KNOW IS THAT THE
EARTH'S MAGNETIC FIELD REVERSES

ITSELF.

LAST REVERSED ITSELF 700,000
YEARS AGO, AND WHEN THIS

HAPPENS, COMPASS DIRECTIONS WILL
SLIP FROM NORTH TO SOUTH, AND

THE MAY GETTIZATION WILL CHANGE
OF THE EARTH, SUCH THAT MOLTEN

ROCKS WHICH FREEZE CAN RECORD
THE HISTORY OF THE EARTH'S

MAGNIFICENTIC -- MAGNITUDIC
FIELD, AND THIS IS HOW WE KNOW

ABOUT THE BLAST TAKE TECTONIC
MOVEMENTS, AND WE CAN RECORD THE

CHANGING EARTH'S MAGNETIC FIELD.

>> VIRGINIA, BEFORE WE RUN OUT
OF TIME LET ME ASK YOU, WHY DID

YOU PICK A JOB THAT DEALS WITH
GEOLOGY?

>> I JUST LIKE ROCKS.

I LIKE BEING OUTDOORS.

AND I LIKE USING MY MIND IN
SOLVING PROBLEMS.

AND I FOUND THAT GEOLOGY WAS A
PLACE WHERE I COULD BE OUTDOORS,

AND I COULD OBSERVE THINGS, AND
I WAS USING MY MIND AT THE SAME

TIME THAT I WAS ENJOYING BEING
OUTDOORS.

SO, I JUST LIKED IT.

AND I'M LUCKY THAT I FOUND A JOB
WHERE I CAN, ACTUALLY, GET PAID

FOR DOING GEOLOGY.

>> JEFF, IF SOMEONE IS
INTERESTED IN FINDING A JOB IN

EARTH SCIENCE, WHAT SHOULD HE OR
SHE STUDY IN SCHOOL?

>> SCIENCE IS ONE OF THE CAREERS
THAT IS JUST SO EXCITING FOR A

NUMBER OF REASONS.

YOU HAVE ENTIRE FREEDOM TO
EXPLORE NEW AREAS OF RESEARCH

THAT NO ONE ELSE KNOWS ABOUT.

IN ORDER TO BECOME A SCIENTIST,
THE BEST SKILLS TO LEARN IN

SCHOOL ARE ALL SKILLS, INCLUDING
MATH, INCLUDING SCIENCE, AND

BELIEVE IT OR NOT, INCLUDING
WRITING SKILLS.

EVEN SCIENTISTS, WHO ARE THE
MARTYRS IN TERMS OF THE MATH AND

SCIENCE, NEED TO BE ABLE TO
CONVEY THEIR IDEAS TO OTHER

PEOPLE AND TELL THEIR STORY TO
THE WORLD.

>> THANK YOU, VIRGINIA AND JEFF
FOR ANSWERING QUESTIONS.

I APPRECIATE YOU TAKING THE TIME
TODAY.

>> THANK YOU, JOAN AND TO ALL
THE STUDENTS WHO SUBMITTED GREAT

QUESTIONS TODAY.

>> GREAT QUESTIONS.

KEEP STUDYING SCIENCE.

>> YES.

>> OUR THANKS, ALSO, TO THE
FOLKS HERE AT BOISE STATE

UNIVERSITY'S EARTH SCIENCE
RESEARCH LAB FOR HOSTING US.

YOU CAN LEARN LOTS MORE ABOUT
THE EARTH AND LOTS OF OTHER

SCIENCE TOPICS ON THE SCIENCE
TREK WEBSITE.

WE'LL ANSWER MORE QUESTIONS
ABOUT THE EARTH ON SCIENCE TREK

THE WEB SHOW.

IF YOU WANT TO SUBMIT A QUESTION
FOR SCIENCE TREK, IT'S EASY.

YOU AND YOUR CLASS CAN WIN
PRIZES.

YOU CAN SEND US AN EMAIL OR A
VIDEO QUESTION AND RECORD IT ON

YOUR WEB CAM OR CELL PHONE, AND
IF YOU ARE AN EDUCATOR, WE'LL

LEND YOU A CAMERA.

THE LAST PRIZE WINNER WAS DILLON
IN MRS. JACOB'S CLASS AT KAMIAH

ELEMENTARY.

SO TO FIND OUT ABOUT THE EARTH
AND HOW TO SEND IN QUESTIONS AND

WIN, GO TO THE SCIENCE TREK
WEBSITE.

EACH WEEK, CHECK OUT MY BLOG FOR
THE LATEST SCIENCE NEWS FOR

KIDS.

YOU WILL FIND IT ALL AT
IDAHOPV.ORG/SCIENCETREK.

THANKS FOR JOINING US.

WE'LL SEE YOU NEXT TIME ON
SCIENCE TREK.

>>> PRESENTATION OF SOIRG ON
IDAHO PUBLIC TELEVISION IS MADE

POSSIBLE THROUGH THE GENEROUS
SUPPORT OF THE LAURA MOORE

CUNNINGHAM FOUNDATION.

COMMITTED TO FULFILLING THE
MOORE FAMILY LEGACY OF BUILDING

THE GREAT STATE OF IDAHO.

>>> IF YOU WANT TO LEARN MORE
ABOUT THIS TOPIC OR WATCH OUR

VIDEOS, CHECK OUT THE SCIENCE
TREK WEBSITE AT