>>> SOUNDS FILL OUR EARS.
TALKING, MUSIC, EVEN SOME
SCIENTIFIC EXPERIMENTS.
THEY ALL START WITH SOUND.
BUT WHAT IS SOUND?
WANT TO FIND OUT?
WE'RE HERE TO ANSWER YOUR
QUESTIONS.
STAY TUNED.
"D4K" IS NEXT.
>> HI, I'M JOAN CARTAN-HANSEN.
WELCOME TO "D4K," THE PLACE FOR
SCIENCE.
BEFORE WE GO TO YOUR QUESTIONS,
LET'S LEARN A BIT MORE ABOUT
SOUND.
SOUND IS A FORM OF ENERGY, LIKE
LIGHT OR ELECTRICITY.
SOUNDS ARE MADE BY SMALL
VIBRATIONS CALLED SOUND WAVES.
SOUND WAVES MOVE BY THE
SQUEEZING AND STRETCHING OF AIR.
WHEN A SOUND OCCURS, MOLECULES
ARE SQUEEZED TOGETHER.
ONE MOLECULE SQUEEZES INTO THE
NEXT WYNN, AND PULLED BACK IN
PLACE BY THE ONE ON THE OTHER
SIDE.
THE MOLECULES MOVE THE SOUND
ALONG IN A WAVE.
SCIENTISTS STUDY SOUND WAVES ON
A MACHINE CALLED AN
OSCILLOSCOPE.
LOUD SOUNDS HAVE MORE ENERGY.
SO THEIR WAVES ARE BIGGER AND
HAVE A GREATER HEIGHT.
SOFT SOUNDS CREATE SMALLER
WAVES.
THE HEIGHT OF A WAVE IS CALLED
ITS AMPLITUDE.
THE FREQUENCY OR NUMBER MUCH
VIBRATIONS PER SECOND,
DETERMINES A SOUND'S PITCH.
SOUND FREQUENCY IS MEASURED IN
HERTZ.
THE HIGHER THE FREQUENCY, THE
HIGHER THE PITCH, AND THE
GREATER THE HERTZ.
>> I ONLY HAVE ONE PAGE OF MATH.
>> HUMANS CAN HEAR SOUNDS
BETWEEN 20 AND 20,000 HERTZ.
BUT OTHER ANIMALS CAN HEAR EVEN
MORE.
ELEPHANTS CAN HEAR SOUNDS MUCH
LOWER THAN HUMANS CAN.
AND BATS HEAR FREQUENCIES MUCH
TOO HIGH FOR HUMANS.
BATS USE HIGH-PITCHED SOUND
WAVES LIKE RADAR TO LOCATE THEIR
FOOD.
AND JUST BECAUSE WE CAN'T HEAR
VERY HIGH AND VERY LOW FREQUENCY
SOUNDS, DOESN'T MEAN WE CAN'T
USE THEM.
SCIENTISTS TRY TO DETECT VERY
LOW INFRASONIC SOUNDS TO STUDY
POTENTIAL EARTHQUAKE AND TO
PREDICT VOLCANO ERUPTIONS.
DOCTORS USE VERY HIGH FREQUENCY
SOUNDS TO TAKE PICTURES INSIDE
THE HUMAN BODY, LIKE THESE OF A
BABY INSIDE A WOMAN'S WOMB.
SOUND WAVES EXERT PRESSURE.
THE AMOUNT OF A SOUND'S PRESSURE
OR LOUDNESS IS MEASURED IN
DECIBELS.
DECIBELS IS ALSO A MEASURE OF
INTENSITY.
THE CLOSER YOU ARE, THE STRONGER
THE FORCE.
SO SAY WERE YOU STANDING NEXT TO
LEAVES IN A LIGHT WIND.
THAT SOUND WOULD MEASURE ABOUT
10 DECIBELS.
A TOILET FLUSH IS ABOUT 67
DECIBELS.
YOUR HAIR DRYER IS ABOUT 80
DECIBELS.
AND THE SPACE SHUTTLE TAKING OFF
IS ABOUT 200 DECIBELS.
PROLONGED EXPOSURE TO SOUNDS
ABOVE 85 DECIBELS CAN DAMAGE
YOUR HEARING, SO BE SURE TO WEAR
EAR PLUGS IF YOU'RE DOING
SOMETHING AROUND LOUD SOUNDS.
AND BE SURE THE VOLUME IN YOUR
HEADPHONES IS SET AT A SAFE
LEVEL.
SOUND SURROUNDS AND DEFINES OUR
WORLD.
SO LISTEN UP, AND APPRECIATE
SOUND.
[APPLAUSE]
>> JOINING ME NOW TO ANSWER YOUR
QUESTIONS ABOUT SOUND ARE TWO
SCIENTISTS.
IN OUR POCATELLO STUDIO IS STEVE
SHROPSHIRE, PROFESSOR OF PHYSICS
AT IDAHO STATE UNIVERSITY.
THANK YOU FOR JOINING US.
>> THANK YOU FOR HAVING ME.
>> AND JOINING ME HERE IN BOISE
IS KATHRYN DEVINE, ASSISTANT
PROFESSOR OF PHYSICS AT THE
COLLEGE OF IDAHO.
LET'S GO TO YOUR QUESTIONS.
>> MY NAME IS JACK, AND I GO TO
SHADOW HILLS ELEMENTARY, AND MY
QUESTION IS, HOW ARE SOUNDS
MADE?
>> WHEN YOU MAKE A SOUND YOU'RE
ACTUALLY GETTING A LITTLE BIT OF
ENERGY TO THE AIR AROUND YOU.
AND SO SOUND IS A WAVE, A
COMPRESSION WAVE OF ALL THE MALL
CIEWLS IN THE AIR, CARRYING THAT
ENERGY FROM WHATEVER MADE THE
SOUND, MY VOICE, ALL THE WAY TO
YOUR EAR.
SO IT'S A WAVE TRAVELING THROUGH
THE AIR.
>> MY NAME IS SHELBY.
MY QUESTION IS, HOW FAST AND HOW
FAR DOES SOUND TRAVEL?
>> WELL, AT ROOM TEMPERATURE
SOUND TRAVELS AT ABOUT 330
METERS PER SECOND.
THAT'S OVER 300 YARDS EVERY
SECOND, SO IT'S QUITE FAST.
AND SOUNDS CAN TRAVEL A GREAT
DEAL OF DISTANCES.
WHEN A VOLCANO NEAR INDONESIA
EXPLODED BACK IN THE 1800s,
THE SOUND WAS HEARD FOR HUNDREDS
AND HUNDREDS OF MILES.
AND THAT'S THROUGH THE AIR.
SOUND ACTUALLY TRAVELS A LITTLE
BIT BETTER THROUGH WATER.
WE KNOW WHALES CAN COMMUNICATE
WITH EACH OTHER OVER HUNDREDS OF
MILES OF OCEAN.
>> NOAH FROM DALTON ELEMENTARY
WOULD LIKE TO KNOW, WHY DOES
SOUND TRAVEL IN WAVES?
>> WELL, A WAVE IS A DISTURBANCE
IN SOMETHING.
AND IF YOU PUSH ON SOMETHING,
LIKE A TABLE, YOU EXPECT THE
WHOLE TABLE TO MOVE.
BUT WITH AIR OR WATER, WHEN YOU
PUSH ON ONE PART OF IT, IT TAKES
A WHILE FOR THAT DISTURBANCE TO
MOVE, TO GET A BUNCH OF OTHER
STUFF.
IT'S LIKE WHEN YOU SPLASH
SOMETHING IN WATER, THROW A ROCK
IN WATER, ALL THE WATER DOESN'T
MOVE AT ONCE.
BECAUSE IT'S KIND OF FLUID.
YOU'LL HAVE A DISTURBANCE
TRAVELING OUTWARDS IN A WAVE.
WE SEE THAT IN WATER QUITE
OFTEN, AND THAT'S REALLY WHAT
HAPPENED -- WHAT IS HAPPENING IN
AIR TOO, WITH THE SOUND WE HEAR,
WE JUST DON'T SEE THE AIR MOVING
IN THE SAME WAY.
BUT IT DOES.
>> HI, MY NAME IS ALYSSA, AND I
GO TO WHITMAN ELEMENTARY SCHOOL
LEWISTON.
MY QUESTION IS, HOW DOES SOUND
TRAVEL THROUGH SPACE?
>> SOUND JUST LIKE YOU'VE JUST
SAID, WHERE YOU HAVE ONE KIND OF
PERSON PART OF THE AIR, ONE
MOLECULE COMMUNICATING THAT WAVE
TO THE NEXT ONE, THAT SAME THING
HAPPENS IN SPACE.
THE THING THAT'S DIFFERENT IS
THAT OUT IN SPACE, THE DENSITY
OF THE AIR IS A LOT LOWER, SO
THE MOLECULES ARE FARTHER APART.
AND SO SOUND CAN STILL TRAVEL IN
SPACE AS LONG AS THERE IS ANY
GAS OR MOLECULES OR ANYTHING
THERE TO COMMUNICATE F THERE
WASN'T ANYTHING THERE, SOUND
WOULDN'T BE ABLE TO TRAVEL.
SO THERE DOES HAVE TO BE A GAS
CLOUD OR SOME MOL YOU'LL OUT
THERE THAT CAN COMMUNICATE THE
ENERGY TO THE NEXT ONE.
>> MY NAME IS BRADEN, AND I GO
TO LENA IN MOSCO, IDAHO.
MY QUESTION IS, WHY DO A TRUMPET
AND A SAXOPHONE SOUND DIFFERENT,
EVEN WHEN THEY ARE PLAYING THE
SAME NOTE AT THE SAME VOLUME?
>> YOU'VE PROBABLY NOTICED
LONGER AND BIGGER INSTRUMENTS
MAKE LOWER PITCHED SOUNDS, LOWER
NOTES, AND SHORTER AND SMALLER
INSTRUMENTS MAKE HIGHER PITCHED
SOUNDS.
THAT HAS TO DO WITH HOW THE
SOUND RESONATES IN THESE
DIFFERENT INSTRUMENTS.
TO ILLUSTRATE I HAVE SOME LITTLE
PIPES HERE.
AND THIS ONE IS CUT A LITTLE
LONGER THAN THE OTHERS, AND WHEN
I WHACK IT ON MY PALM, I GET A C
NOTE.
AND WITH THE BLACK ONE, THAT'S A
D, ORANGE ONE, E, F, G, AND AN
A.
YOU CAN SEE THE SHORTER THE PIPE
THE HIGHER THE PITCH.
I'VE GOT SOMETHING YOU CAN DO AT
HOME WITH A LITTLE PLASTIC
STRAW.
IF YOU TAKE A STRAW AND YOU CUT
LITTLE GROOVES IN IT, SHAPED
LIKE TRIANGLES, LIKE I HAVE
HERE, AND YOU BITE IT DOWN WITH
YOUR TEETH, YOU CAN MAKE A
LITTLE REED.
A LOT OF INSTRUMENTS WORK ON
REEDS.
WHEN YOU BLOW AIR BETWEEN THE
REEDS, THEY VIBRATE.
AND THE LONGER THE INSTRUMENT,
THE LOWER THE PITCH OF SOUND
WILL RESONATE IN THAT.
AND SO IF I JUST BLOW ON THIS
STRAW, WE GET A NOTE, AND IF I
TAKE TWO STRAW AND STICK THEM
TOGETHER, I'LL GET A LOWER
PITCH.
AND I CAN EVEN CHANGE THE LENGTH
OF THE PIPE AND GET DIFFERENT
PITCHES FROM THE SAME STRAW.
*
>> THAT'S GREAT.
[LAUGHTER]
OK.
LET'S GO BACK TO THE QUESTIONS.
>> HI, MY NAME IS SARAH, I GO TO
ST. MARY'S ELEMENTARY, AND MY
QUESTION IS, WHY -- HOW DOES
SOUND TRAVEL BETTER THROUGH
WATER?
>> WELL, WATER IS DENSER.
THERE'S MORE STUFF THERE IN A
SMALLER SPACE, AND THE MOLECULES
ARE CLOSER TOGETHER, AND SO WHEN
SOME MOLECULES GET THE ENERGY
FROM THE SOUND, FROM THE
DISTURBANCE, THEY WILL COLLIDE
WITH OTHER MOLECULES SOONER, AND
MORE RAPIDLY.
AND ALSO WATER IS A LITTLE MORE
ELASTIC THAN AIR, AND YOU CAN
THINK OF IT AS BEING STIFFER IN
A WAY.
AND ALL THAT CONTRIBUTES TO
MAKING THE SOUND TRAVEL BETTER
AND FARTHER.
>> ONE OF THE THINGS I'VE ALWAYS
FOUND INTERESTING, I DON'T KNOW
ABOUT THE AUDIENCE OUT THERE,
BUT I ALWAYS TRIED TO TALK TO MY
BROTHER UNDER WATER WHEN WE WERE
KIDS.
IT WOULD ALWAYS SOUND WEIRD.
THAT'S BECAUSE WATER TRANSMITS
DIFFERENT FREQUENCIES AT
DIFFERENT SPEEDS, SO OUR EARS
ARE USED TO HEARING SOUNDS IN
AIR.
BUT EVEN THOUGH WATER CAN
TRANSMIT SOUNDS FASTER BETTER,
IT DOESN'T TRANSMIT IT IN A WAY
OUR EARS ARE USED TO HEARING,
WHICH IS WHY IT SOUNDS GAR
ABOUTED.
>> IS THERE AN OBJECT SO THICK
OR SO STRONG THAT SOUND CAN'T
PASS THROUGH IT?
>> IT KIND OF DEPENDS, I GUESS,
ON HOW YOU THINK ABOUT IT.
SOUND IS ENERGY TRAVELING, IT'S
AN ENERGY WAVE, SO THE LOUDER
THE SOUND, THE MORE ENERGY
YOU'RE PUTTING IN, THE THICKER
SOMETHING WOULD HAVE TO BE TO
STOP THE ENERGY FROM TRAVELING
THROUGH IT.
AND SO, FOR EXAMPLE, IF I WAS
WHISPERING AND YOU HAD JUST A
WALL, THAT WOULD BE ENOUGH TO
STOP THE SOUND FROM TRAVELING
THROUGH IT.
BUT IF I WAS SHOUTING, MAYBE A
WALL WOULDN'T BE ENOUGH AND IT
WOULD HAVE TO BE THICKER.
IT DEPENDS ON HOW LOUD THE SOUND
IS OR HOW THICK SOMETHING WOULD
HAVE TO BE TO BLOCK THE SOUND.
>> HI, MY NAME IS SEAN, AND I'M
FROM ILLINOIS.
MY QUESTION IS, HOW FAR CAN THE
FIRE ALARM SOUND POSSIBLY
TRAVEL?
>> DEPENDS ON THE FIRE ALARM AND
IT DEPENDS ON WHAT'S IN THE WAY
OF THE FIRE ALARM.
AGAIN, THE THINGS THAT CAN MAKE
SOUND TRAVEL FARTHER IS THE
AMOUNT OF ENERGY THAT IS BEING
PRODUCED OR THAT THE SOUND IS
GIVING OUT.
AND SO IF YOU -- IT DEPENDS ON
THE VOLUME OF YOUR FIRE ALARM
AND THE FIRE ALARM.
SOMETIMES BIG APARTMENT
BUILDINGS HAVE VERY HIGH ENERGY
LOUD FIRE ALARMS, LIKE IN A
SCHOOL BUILDING BECAUSE THEY
HAVE TO BE ABLE TO HEARD TROUT
THE WHOLE BUILDING, VERSUS THE
FIRE ALARM IN MY BEDROOM ISN'T
AS LOUD, IT PRODUCES LESS
ENERGY.
SO YOU WOULDN'T BE ABLE TO HEAR
IT PROBABLY AS FAR AS MY
NEIGHBOR'S HOUSE.
BUT IF A FIRE ALARM IN A BIG
BUILDING GOES OFF YOU CAN HEAR
IT FARTHER AWAY.
IT COMES DOWN TO HOW MUCH ENERGY
THE SOUND IS GIVING OFF, HOW
MUCH ENERGY IS GOING ON AT THE
SOURCE.
>> DID YOU KNOW THAT DOLPHINS ON
COULD HEAR SOUNDS UNDER WATER
FROM 15 MILES AWAY?
SNAKES ON THE OTHER HAND HAVE NO
EARS.
THEY SENSE SOUND WITH THEIR
TONGUES.
CAMERON AT DOLL TON ELEMENTARY
WOULD LIKE TO KNOW, HOW MANY
ANIMALS USE SOUND TO NAVIGATE
THEIR WAY AROUND THE WORLD?
>> LOTS OF THEM.
WE KNOW THAT BATS USE SOUND TO
NAVIGATE, AND TO HUNT.
THEY ACTUALLY LISTEN VERY
CLOSELY TO THE SOUND, THE ECHOS
OF THE SOUND THAT BOUNCE OFF OF
THE INSECTS AND OBJECTS AROUND
THEM.
ALSO A LOT OF THINGS THAT LIVE
IN WATER.
SINCE SOUND TRAVELS SO WELL
THROUGH WATER, A LOT OF FISH AND
OCEAN CREATURES USE SOUND TO
NAVIGATE, AND ALSO TO HUNT.
AND THERE'S EVEN SOME BIRDS
THAT DO THAT TOO.
>> MA TILDA, ALSO FROM DALTON
GARDENS ELEMENTARY WOULD LIKE TO
KNOW, WHY CAN'T YOU SEE SOUND
WAVES?
>> SO A SOUND WAVE IS A LITTLE
TINY MOLECULE THAT YOU CAN'T
SEE.
SO I GUESS IT GOES DOWN TO THE
FACT YOU CAN'T SEE THE AIR, EVEN
THOUGH THERE IS STUFF IN THE AIR
BETWEEN US, YOU CAN'T SEE IT.
THERE'S NOTHING THAT I CAN SEE
HERE.
BUT THAT'S THIS AIR IN FRONT OF
ME IS WHAT IS MAKING THE SOUND
WAVE PROPAGATE THROUGH.
I SUPPOSE IF YOU HAD AMAZING
EYES AND COULD SEE THE MOLECULES
MOVING, YOU WOULD BE ABLE TO SEE
THE SOUND WAVE, BUT WE CAN'T
ACTUALLY SEE THE SMALL, SMALL
THINGS IN THE AIR THAT ARE
TRANSMITTING THE SOUND WAVE
ALONG THE AIR.
>> IF I COULD JUMP IN, THERE
IS -- IF YOU EVER WATCHED
EXPLOSIONS, OR VERY, VERY LOUD
NOISES, YOU SEE IT A LOT WITH
ARTILLERY, SAY WITH THE ARMY.
YOU CAN ACTUALLY SEE WHAT LOOKS
LIKE A SOUND WAVE, BUT WHAT
YOU'RE SEEING IS YOU HAVE SO
MUCH ENERGY BEING DEPOSITED IN
THE AIR, THE WATER IN THE AIR
CONDENSES OUT INTO LITTLE WATER
DROP LET'S, AND YOU'LL ACTUALLY
SEE WHAT LOOKS LIKE A WAVE
TRAVELING THROUGH THE AIR, BUT
IT'S REALLY THE WATER CONDENSING
OUT BRIEFLY AS THE SOUND WAVE
GOES THROUGH IT.
SO YOU'RE NOT ACTUALLY SEEING
THE AIR, BUT YOU'RE SEEING WATER
THAT'S BEING IN A WAY DRIVEN OUT
OF THE AIR BRIEFLY BY THE
INTENSE SOUND.
>> HI, MY NAME IS ANNE.
MY QUESTION IS, HOW FAST DO YOU
HAVE TO GO TO BREAK THE SOUND
BARRIER?
>> THE SPEED OF SOUND IS 330
METERS PER SECOND.
HERE AT ROOM TEMPERATURE.
SO THAT'S ABOUT HOW FAST YOU'D
HAVE TO GO.
ABOUT 330 YARDS EVERY SECOND.
>> HI.
MY NAME IS McKENNA, I GO TO
RUSSELL SCHOOL IN MOSCO.
MY QUESTION IS, WHY IS THE SPEED
OF LIGHT FASTER THAN THE SPEED
OF SOUND?
>> THAT'S ACTUALLY A REALLY
INTERESTING QUESTION.
LIGHT WAVES AND SOUND WAVES ARE
A PRETTY DIFFERENT AND VERY
FUNDAMENTAL WAY.
SO SOUND WAVES REQUIRE THAT YOU
HAVE AIR OR GAS OR SOMETHING
THAT WILL TRANSMIT, SOME
MOLECULE THAT WILL TRANSMIT THE
WAVE, BECAUSE THEY HAVE TO PASS
THE SIGNAL TO THE NEXT MOLECULE
TO PASS THE WAVE ALONG.
LIGHT, ON THE OTHER HAND, IF YOU
HAD A VACUUM WHICH IS A TOTAL
ABSENCE OF ANYTHING, TOTALLY
EMPTY SPACE, YOU CAN STILL HAVE
A LIGHT WAVE TRAVEL THROUGH IT
BECAUSE LIGHTS -- LIGHT TRAVELS
THROUGH A FIELD, IT DOESN'T
REQUIRE HAVING MOLECULES.
SO KIND OF OFF TOPIC, BUT
THEY'RE VERY DIFFERENT AND VERY
INTERESTING.
THE SPEED THEN SINCE LIGHT
DOESN'T DEPEND ON MOLECULES
COMPRESSING INTO EACH OTHER TO
TRANSMIT THE WAVE ALONG, THEY
CAN TRAVEL FASTER, SO IT HAS TO
DO WITH HOW THE
WAVE -- PROPAGATES THROUGH
SPACE.
SO IT JUST A VERY DIFFERENT WAY
OF HAVING THE ENERGY TRAVEL
THROUGH SPACE THAT MAKES IT SO
LIGHT CAN GO FASTER.
>> JACK FROM DALTON ELEMENTARY
WOULD LIKE TO KNOW, HOW DOES
YOUR VOICE ECHO?
>> YOUR VOICE ECHOS WHEN THE
SOUND BOUNCES OFF OF SOMETHING
ELSE.
IT'S BASICALLY A REFLECTION OF
THE SOUND.
AGAIN, USING THE ANALOGY OF
THROWING A ROCK INTO WATER, IF
YOU'VE GOT LIKE A STIFF BANK, A
CONCRETE POND, YOU'LL SEAT WATER
RIPPLES HITTING THE EDGE OF THE
POUND EVER POND AND BREAKING
BACK.
THE SAME THINGS HAPPEN WITH YOUR
ECHO, AND YOU CAN HEAR THE SOUND
BOUNCING OFF OF SOMETHING.
SO IT'S LIKE THE SOUND WAVE IS
MOVING AND HITS SOMETHING AND
BOUNCES RIGHT BACK TOWARDS YOU.
SO YOU CAN HEAR YOUR OWN VOICE
AGAIN.
OR OTHER SOUNDS, TOO.
SO IT'S BASICALLY A BOUNCING OFF
THE SOUND OFF SOMETHING ELSE.
>> MY NAME IS ALYSSA, HOW DOES
SOUND TRAVEL TO iPOD TO
HEADPHONES?
>> IT'S NOT SOUND TRAVELING
THROUGH THE CORD, IT'S BASICALLY
AN ELECTRICAL SIGNAL.
AND THE ELECTRICAL SIGNAL GOES
TO A SPEAKER, AND THE ENERGY OF
THE ELECTRICITY MAKES A LITTLE
MEMBRANE THERE VIBRATE.
AND SOMETHING VIBRATES, IT WILL
MOVE THE AIR AROUND IT.
SO THE SOUND IS ONLY EXISTS
THERE AT THE SPEAKER INSIDE YOUR
EAR.
IT DOESN'T EXIST INSIDE THE
CORD.
THAT'S ELECTRICITY.
IT CARRIES THAT INFORMATION THAT
BASICALLY MAKES THE SPEAKER
MOVE.
>> A LOT OF YOU HAD QUESTIONS
ABOUT SOUND AND HEARING.
SO LET'S LEARN A LITTLE BIT MORE
ABOUT HOW OUR EARS AND BRAINS
HEAR SOUND.
>> WHEN YOU MAKE A SOUND, YOU
CREATE ENERGY IN THE FORM OF
SOUND WAVES.
A LOUD SOUND HAS TALLER WAVES
THAN A SOFT ONE.
THESE WAVES EVENTUALLY ENTER
YOUR EARS.
THE SOUND WAVES TRAVEL DOWN THE
EAR CANAL.
THE EAR CAN AM IS ABOUT AN INCH
LONG, AND AT ITS END IS A THIN
PIECE OF SKIN CALLED THE
EARDRUM.
THE EARDRUM IS STRETCHED TIGHT,
JUST LIKE THE TOP OF A DRUM.
WHEN THE SOUND WAVES HIT THE
EARDRUM, IT BEGINS TO VIBRATE.
THAT VIBRATION MAKES THREE TINY
BONES IN YOUR MIDDLE EAR BEGIN
TO MOVE.
THESE THREE LITTLE BONES ARE
KNOWN AS THE HAMMER, ANVIL, AND
STIR UP, BECAUSE THAT'S WHAT
THEY KIND OF LOOK LIKE.
THEY FEEL THE BONES TRANSMIT OR
MOVE THE SOUND WAVES ALONG TO
THE INBOUNDER EAR.
THEY ALSO INCREASE THE FORCE OF
SOUND WAVES.
THEY MOVE INTO A SNAIL SHAPED
STRUCTURE CALLED THE COKE LEE A.
THEY'RE FILLED WITH FLUID AND
17,000 HAIRLIKE TISSUES.
SOUND WAVES MOVE THROUGH THE
FLUID AND THE HAIR BENDS.
SOMEHOW THE MOVEMENT OF THOSE
HAIRS STIMULATES THE 30,000
NERVE FIBERS.
THAT NERVE CARRIES THE SIGNAL TO
THE BRAIN AND THE BRAIN FIGURES
OUT WHAT THE SOUND IS.
YOU NEED TWO EARS TO FIGURE OUT
WHERE A SOUND COMES FROM.
YOUR BRAIN FIGURES THE TERRENCE
BETWEEN THE TWO SOUND LEVELS,
AND CALCULATES THE DIRECTION OF
THE SOUND.
IT'S IMPORTANT TO PROTECT YOUR
HEARING FROM LOUD SOUNDS.
MUSCLES IN THE MIDDLE EAR
PROTECT THE EAR BY STIFFENING
THE EARDRUM, OR BY MOVING THE
STIR UP BONE AWAY FROM THE INNER
EAR.
BUT SUDDEN LOUD SOUNDS CAN BREAK
THE EARDRUM OR CAUSE OTHER
DAMAGE AND CONTINUED LOUD SOUNDS
CAN DAMAGE THE TINY HAIRS IN THE
COCHLEA.
BE SURE TO WEAR HEARING
PROTECTION IF YOU'RE GOING TO BE
AROUND LOUD NOISES, AND TURN THE
VOLUME DOWN ON YOUR HEADPHONES.
BECAUSE ONCE YOUR HEARING IS
DAMAGE THE, IT CAN'T BE MADE ALL
BETTER.
ABOUT 200,000 AMERICANS ARE
DEAF.
THAT MEANS THEY CAN'T HEAR
ANYTHING.
ANOTHER 3 MILLION HAVE SEVERE
HEARING PROBLEMS.
SOME USE HEARING AIDS TO AMPLIFY
OR INCREASE THE STRENGTH OF
SOUND WAVES SO THEY CAN HEAR
BETTER.
OTHERS HAVE A COCHLEAR IMPLANT.
THAT'S WHERE A SMALL MICROPHONE
HELPS TRANSMIT SOUND TO THE
INNER EAR.
INDIVIDUALS WHO ARE DEAF OR HARD
OF HEARING SOMETIMES USE SIGN
LANGUAGE TO COMMUNICATE.
OTHERS CAN READ LIPS.
COMMUNICATING, WHETHER IT'S WITH
YOUR EARS OR YOUR HANDS, IS
ESSENTIAL TO LIFE.
BY THE WAY, YOUR EAR DOES ONE
OTHER THING -- REMEMBER THE
COCHLEA?
MOVEMENT OF THE FLUID INSIDE
THAT TELLS THE BRAIN ABOUT YOUR
BODY POSITION.
THAT WAY YOU CAN TELL UP FROM
DOWN, EVEN WITH YOUR EYES
CLOSED.
WHEN YOU SPIN AROUND, THE FLUID
IN THE COCHLEA SPINS TOO, AND
THAT EXPLAINS WHY YOU FEEL
DIZZY.
>> HI, MY NAME IS JOY, I GO TO
WHITMAN ELEMENTARY SCHOOL.
MY QUESTION IS, HOW DO YOU HEAR
SOUNDS IN YOUR EARS?
>> OK.
SO YOUR EARS I THINK YOU HAVE
PROBABLY NOTICED, YOUR EARS HAVE
A LITTLE HOLE IN THEM, THERE'S A
LITTLE ENTRANCE THERE.
SO THE SOUND WAVES COME IN AND
THEY HIT THAT ENTRANCE TO YOUR
EAR, AND THEN WHAT -- YOU HAVE
LITTLE HAIRS IN YOUR EAR THAT
RESPOND TO THE WAVES, SO JUST
KIND OF LIKE SEAWEED IN A POND
THAT'S GETTING MOVED AROUND BY
THE WAVES IN THE WATER, THE
SOUND WAVE MOVES THESE LITTLE
DETECTORS IN YOUR EAR AROUND,
AND THOSE TRANSMIT A SIGNAL TO
THE NERVOUS SYSTEM THAT
EVENTUALLY COMMUNICATES THAT
INFORMATION TO YOUR BRAIN AND
TELLS YOU WHAT KIND OF SOUND
YOU'RE HEARING.
>> MY NAME IS KENDALL, I GO TO
CAMELOT ELEMENTARY, AND MY
QUESTION IS, WHY DO LOUD NOISES
HURT OUR EARS?
>> AGAIN, WITH THE LITTLE HAIRS
IN YOUR EARS, A LOUD SOUND, THAT
WOULD BE LIKE A WAVE THAT'S TOO
BIG IN THE EXPOND SMASHES ALL
THE SEAWEED DOWN.
SO IF YOU HAVE A WAVE THAT'S TOO
MUCH ENERGY COMING TO YOUR EAR,
IT CAN HURT ALL THOSE LITTLE
DETECTORS BECAUSE THEY'RE NOT
CLIPPED, ARE -- THEY'RE NOT
EQUIPPED OR THEY'RE NOT READY
FOR ALL THAT ENERGY.
IT CAN ACTUALLY HURT THE
DETECTORS IN YOUR EAR, AND THEN
IF YOU HAVE EVER HEARD A REALLY
LOUD NOISE THAT CAUSES RINGING
IN YOUR EAR, THE INABILITY TO
HEAR AS WELL THAN BEFORE YOU
HEARD THE LOUD NOISE, IT'S
BECAUSE YOU DAMAGED THE
DETECTORS IN YOUR EAR.
>> HANNAH WOULD LIKE TO KNOW IF
THERE'S A CLASSROOM FULL OF KIDS
AND THE TEACHER WAS SPEAKING,
WOULD THE KIDS ALL HEAR THE
SOUND AT THE SAME TIME?
>> NO.
THEY WOULDN'T.
BUT IN A CLASSROOM, IT'S ENOUGH
SPACE SO THAT AGAIN, SOUND
TRAVELS AT ABOUT 330 METERS PER
SECOND, THE TYPICAL CLASSROOM IS
ONLY MAYBE A DOZEN METERS, MAYBE
AT MOST 15 METERS LONG.
AND SO YOU'RE TALKING ABOUT TINY
FRACTIONS OF A SECOND DIFFERENCE
BETWEEN WHEN SOMEONE CLOSE TO
THE TEACHER CAN HEAR AND SOMEONE
FAR AWAY.
IF YOU WANT TO BE VERY PICKY,
YES, THEY'LL HEAR IT AT
DIFFERENT TIMES, BUT IT WILL BE
SO QUICK, NO ONE REALLY WILL
NOTICE.
>> YOU COULD NOTICE IT IF YOU
WERE IN A MUCH LARGER SPACE.
SO YOU'VE PROBABLY SEEN THIS
WHEN YOU'VE WATCHED FIREWORKS,
WHERE FIREWORKS, IF YOU'RE VERY
CLOSE TO WHERE THE FIREWORKS ARE
GOING OFF YOU SEE THE EXPLOSION
AT THE SAME TIME YOU HEAR THE
BOOM.
IF YOU'RE FARTHER AWAY, AGAIN,
YOU THAN GET SEVERAL HUNDRED
FEET AWAY FROM THE FIREWORKS AND
STILL BE ABLE TO SEE THEM, THE
PEOPLE CLOSER TO THE FIREWORKS
ARE HEARING THEM SOONER THAN YOU
ARE.
THAT'S HOW YOU GET THAT LAG
BETWEEN WHEN YOU SEE THEM AND
WHEN YOU HEAR THE EXPLOSION.
IT COULD BE OVER A LARGE
DISTANCES TO NOTICE THAT EFFECT.
>> GABE WOULD LIKE TO KNOW, WHAT
IS ULTRASOUND?
>> SO ULTRASOUND IS SOMETHING
THAT I THINK A LOT OF PEOPLE
HEAR ABOUT IN MEDICINE IN TERMS
OF BEING ABLE TO GET AN
ULTRASOUND IMAGE.
THAT'S THE TECHNIQUE OF USING
SOUND, SINCE SOUND WAVES TRAVEL
THROUGH MEDIUM, TO USE SOUND TO
BOUNCE OFF AN OBJECT LIKE INSIDE
THE HUMAN BODY, SO YOU CAN PUT
AN ULTRASOUND MACHINE ON SOME OF
THESE ABDOMEN AND SEE THEM
INSIDE THEM BECAUSE THE SOUND
WAVES COMES THROUGH, INTERACT
WITH SOMETHING DENSER THAN
SOMETHING IN THE REST OF THE
BODY AND REFLECTS BACK OUT AND
SO THEN THE DETECTOR CAN USE
THOSE IMAGES TO MAKE A PICTURE.
>> ELLIE WOULD LIKE TO KNOW HOW
FAR CAN SOUND TRAVEL?
>> THIS DEPENDS ON HOW LOUD THE
ORIGINAL SOUND WAS.
SO THE MORE ENERGY THAT GOES
INTO THE ORIGINAL SOUND, THE
FARTHER IT CAN TRAVEL.
AND SO IF YOU HAVE LIKE A
WHISPER YOU MIGHT NOT BE ABLE TO
HEAR THAT MORE THAN A FEW FEET
AWAY, BUT IF YOU HAVE A LOUD
VOLCANO EXPLODING WITH A LOT OF
ENERGY YOU MIGHT BE ABLE TO HEAR
THAT HUNDREDS OF MILES AWAY.
>> HI.
MY NAME IS CASSIDY, AND I GO TO
WEST PARK ELEMENTARY SCHOOL IN
MOSCOW.
THIS IS MY QUESTION -- ARE THERE
SOFT SOUNDS YOU CAN'T HEAR?
>> OH, YES.
AGAIN, WE HAVE TO HAVE A CERTAIN
AMOUNT OF ENERGY COMING INTO OUR
EARS TO MOVE OUR LITTLE CILIA
AROUND ENOUGH FOR US TO DETECT
THE SOUND.
THERE ARE VERY, VERY FAINT
SOUNDS WE CAN'T HEAR.
IT'S LIKE INSECTS STRACHG
THEMSELVES.
WE'VE BEEN ABLE TO PICK UP THAT
SOUND WITH SENSITIVE
MICROPHONES, BUT NO MATTER HOW
HARD YOU LISTEN I DON'T THINK
YOU CAN HEAR A BUG SCRATCHING
ITS BACK.
>> LET ME ASK A COUPLE OTHER
QUESTIONS.
WHY DID YOU GUYS DECIDE TO STUDY
PHYSICS AND THEREFORE STUDY
ABOUT SOUND?
>> SO WHEN I WAS IN COLLEGE, I
REALLY LIKED MATH.
I WAS GOOD AT MATH, AND I REALLY
LIKED SCIENCE, BUT DIDN'T KNOW
WHAT AREA I WANTED TO GO INTO.
SO MY FIRST YEAR OF COLLEGE I
STARTED WORKING, I TOOK A
PHYSICS CLASS AND REALIZED THAT
THAT WAS THE PERFECT COMBINATION
OF BEING ABLE TO USE MY MATH
SKILLS AND THEN SCIENCE, AND I
STARTED WORKING FOR A PROFESSOR
WHO DID ASTRONOMY, WHICH WAS THE
COOLEST THING TO ME AT THE TIME.
SO THEN I WAS ABLE TO COMBINE
MATH, PHYSICS, AND ASTRONOMY
INTO THE SAME LIFE TRAJECTORY.
SO THAT'S BEEN GREAT.
>> STEVE?
>> WELL, I HAD A VERY GOOD HIGH
SCHOOL PHYSICS TEECHER, AND HE
INSPIRED ME, AND HE STRONGLY
INFLUENCED MY CHOICE OF CAREER
AND STUDY, BUT PHYSICS AND
SCIENCE IN GENERAL, I LIKE THE
IDEA OF BEING ABLE TO FIGURE OUT
HOW THINGS WORK.
HOW THE UNIVERSE WORKS.
WE LIVE IN A WONDEROUS PLACE,
AND LEARNING MORE ABOUT IT IS
JUST FASCINATING.
AND SCIENCE SEEMED TO ME AND
STILL DOES THE BEST WAY TO GO
ABOUT LEARNING MORE ABOUT THE
WORLD AROUND US.
>> STEVE, IF A STUDENT WANTS TO
BECOME A PHYSICIST AND STUDY
SOUND, WHAT SHOULD THEY DO WHEN
THEY GET TO SCHOOL, WHAT CLASSES
SHOULD THEY TAKE?
>> OH, SCIENCE.
SCIENCE AND MATHEMATICS.
MATHEMATICS IS THE LANGUAGE OF
WHICH SCIENCE IS SPOKEN.
SO YOU NEED TO BE FAIRLY FLUENT
WITH MATH IN ORDER TO DO
SCIENCE.
BUT I WOULD SAY SAMPLE AS MANY
SCIENCE CLASSES AS YOU CAN, AND
GO WITH WHAT YOU FIND
INTERESTING.
WHAT FASCINATES YOU.
>> WOULD I AGREE WITH THAT TOO.
THE MATHEMATICS IS IMPORTANT
BECAUSE IT HELPS YOU KIND OF,
AGAIN, SPEAK THE LANGUAGE OF THE
SCIENCES.
WHEN I STARTED TAKING SCIENCE I
TOOK BIOLOGY AND CHEMISTRY, AND
GEOLOGY, PHYSICS, AND THEY'RE
ALL -- THEY ALL GET USED
TOGETHER, THERE'S NOT CLEARLY
SEPARATED OUT FIELDS IN
ASTRONOMY, THERE'S A LOT OF
CHEMISTRY AND IN PHYSICS THERE'S
BIOLOGY.
SO I WOULD HAVE TO AGREE WITH
STEVE, TAKE AS MUCH SCIENCE AS
YOU CAN SO YOU CAN FIND THE
THING YOU'RE REAL LIQUEURUS
ABOUT AND WANT TO KEEP ASKING
QUESTIONS ABOUT.
>> I'M SORRY WE'VE RUN OUT OF
TIME.
I THANK STEVE SHROPSHIRE AND
KATHRYN DEVINE FOR ANSWERING OUR
QUESTIONS.
THANKS, STEVE.
>> THANK YOU.
>> THANKS, KATHRYN.
>> THANKS SO MUCH FOR HAVING US.
>> YOU CAN LEARN LOTS MORE ABOUT
SOUNDS AND OTHER TOPICS ON THE
"D4K" WEBSITE AND WE'LL ANSWER
MORE QUESTIONS ABOUT SOUND IN
THE "D4K" WEB ONLY.
YOU'LL FIND IT ALL AT
IDAHOPTV.ORG/D4K.
OUR LATEST WINNER IN OUR
QUESTION CONTEST IS TAYLOR AT
MRS. HUNT'S CLASS AT CYNTHIA
MANN ELEMENTARY IN BOISE.
REMEMBER, WHEN YOU SEND IN A
QUESTION, YOU AND YOUR CLASS ARE
ELIGIBLE FOR OUR CONTEST.
CHECK OUT THE CONTACT US PART OF
THE "D4K" WEBSITE FOR SHOW
DEADLINES AND HOW TO SUBMIT YOUR
I'M AND VIDEO QUESTIONS.
AND CHECK OUT MY SCIENCE BLOG
FOR THE LATEST SCIENCE NEWS FOR
KIDS.
IDAHOPTV.ORG.
THANKS FOR JOINING US.
WE'LL SEE YOU NEXT TIME ON
"D4K."
Captioning Performed By
LNS Captioning
www.LNScaptioning.com
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