WEBVTT 00:17.917 --> 00:18.551 >>> SOUNDS FILL OUR EARS. 00:18.551 --> 00:21.187 TALKING, MUSIC, EVEN SOME SCIENTIFIC EXPERIMENTS. 00:21.187 --> 00:22.555 THEY ALL START WITH SOUND. 00:22.555 --> 00:23.923 BUT WHAT IS SOUND? 00:23.923 --> 00:24.824 WANT TO FIND OUT? 00:24.824 --> 00:27.027 WE'RE HERE TO ANSWER YOUR QUESTIONS. 00:27.027 --> 00:27.927 STAY TUNED. 00:27.927 --> 00:31.097 "D4K" IS NEXT. 00:44.277 --> 00:45.478 >> HI, I'M JOAN CARTAN-HANSEN. 00:45.478 --> 00:47.681 WELCOME TO "D4K," THE PLACE FOR SCIENCE. 00:47.681 --> 00:52.318 BEFORE WE GO TO YOUR QUESTIONS, LET'S LEARN A BIT MORE ABOUT 00:52.318 --> 00:55.055 SOUND. 00:55.055 --> 00:58.324 SOUND IS A FORM OF ENERGY, LIKE LIGHT OR ELECTRICITY. 00:58.324 --> 01:02.328 SOUNDS ARE MADE BY SMALL VIBRATIONS CALLED SOUND WAVES. 01:02.328 --> 01:06.499 SOUND WAVES MOVE BY THE SQUEEZING AND STRETCHING OF AIR. 01:06.499 --> 01:11.604 WHEN A SOUND OCCURS, MOLECULES ARE SQUEEZED TOGETHER. 01:11.604 --> 01:16.109 ONE MOLECULE SQUEEZES INTO THE NEXT WYNN, AND PULLED BACK IN 01:16.109 --> 01:19.546 PLACE BY THE ONE ON THE OTHER SIDE. 01:19.546 --> 01:23.016 THE MOLECULES MOVE THE SOUND ALONG IN A WAVE. 01:23.016 --> 01:26.252 SCIENTISTS STUDY SOUND WAVES ON A MACHINE CALLED AN 01:26.252 --> 01:26.619 OSCILLOSCOPE. 01:26.619 --> 01:27.654 LOUD SOUNDS HAVE MORE ENERGY. 01:27.654 --> 01:30.457 SO THEIR WAVES ARE BIGGER AND HAVE A GREATER HEIGHT. 01:30.457 --> 01:33.293 SOFT SOUNDS CREATE SMALLER WAVES. 01:33.293 --> 01:36.730 THE HEIGHT OF A WAVE IS CALLED ITS AMPLITUDE. 01:36.730 --> 01:39.532 THE FREQUENCY OR NUMBER MUCH VIBRATIONS PER SECOND, 01:39.532 --> 01:41.735 DETERMINES A SOUND'S PITCH. 01:41.735 --> 01:44.104 SOUND FREQUENCY IS MEASURED IN HERTZ. 01:44.104 --> 01:47.640 THE HIGHER THE FREQUENCY, THE HIGHER THE PITCH, AND THE 01:47.640 --> 01:50.110 GREATER THE HERTZ. 01:50.110 --> 01:52.012 >> I ONLY HAVE ONE PAGE OF MATH. 01:52.012 --> 01:55.482 >> HUMANS CAN HEAR SOUNDS BETWEEN 20 AND 20,000 HERTZ. 01:55.482 --> 01:58.151 BUT OTHER ANIMALS CAN HEAR EVEN MORE. 01:58.151 --> 02:01.688 ELEPHANTS CAN HEAR SOUNDS MUCH LOWER THAN HUMANS CAN. 02:01.688 --> 02:06.526 AND BATS HEAR FREQUENCIES MUCH TOO HIGH FOR HUMANS. 02:06.526 --> 02:11.164 BATS USE HIGH-PITCHED SOUND WAVES LIKE RADAR TO LOCATE THEIR 02:11.164 --> 02:11.431 FOOD. 02:11.431 --> 02:14.901 AND JUST BECAUSE WE CAN'T HEAR VERY HIGH AND VERY LOW FREQUENCY 02:14.901 --> 02:17.971 SOUNDS, DOESN'T MEAN WE CAN'T USE THEM. 02:17.971 --> 02:23.176 SCIENTISTS TRY TO DETECT VERY LOW INFRASONIC SOUNDS TO STUDY 02:23.176 --> 02:26.279 POTENTIAL EARTHQUAKE AND TO PREDICT VOLCANO ERUPTIONS. 02:26.279 --> 02:29.549 DOCTORS USE VERY HIGH FREQUENCY SOUNDS TO TAKE PICTURES INSIDE 02:29.549 --> 02:34.921 THE HUMAN BODY, LIKE THESE OF A BABY INSIDE A WOMAN'S WOMB. 02:34.921 --> 02:36.256 SOUND WAVES EXERT PRESSURE. 02:36.256 --> 02:41.027 THE AMOUNT OF A SOUND'S PRESSURE OR LOUDNESS IS MEASURED IN 02:41.027 --> 02:41.461 DECIBELS. 02:41.461 --> 02:44.030 DECIBELS IS ALSO A MEASURE OF INTENSITY. 02:44.030 --> 02:55.675 THE CLOSER YOU ARE, THE STRONGER THE FORCE. 02:55.675 --> 03:00.080 SO SAY WERE YOU STANDING NEXT TO LEAVES IN A LIGHT WIND. 03:00.080 --> 03:03.883 THAT SOUND WOULD MEASURE ABOUT 10 DECIBELS. 03:03.883 --> 03:07.787 A TOILET FLUSH IS ABOUT 67 DECIBELS. 03:07.787 --> 03:11.057 YOUR HAIR DRYER IS ABOUT 80 DECIBELS. 03:11.057 --> 03:16.062 AND THE SPACE SHUTTLE TAKING OFF IS ABOUT 200 DECIBELS. 03:16.062 --> 03:19.366 PROLONGED EXPOSURE TO SOUNDS ABOVE 85 DECIBELS CAN DAMAGE 03:19.366 --> 03:22.736 YOUR HEARING, SO BE SURE TO WEAR EAR PLUGS IF YOU'RE DOING 03:22.736 --> 03:24.437 SOMETHING AROUND LOUD SOUNDS. 03:24.437 --> 03:29.709 AND BE SURE THE VOLUME IN YOUR HEADPHONES IS SET AT A SAFE 03:29.709 --> 03:30.377 LEVEL. 03:30.377 --> 03:32.445 SOUND SURROUNDS AND DEFINES OUR WORLD. 03:32.445 --> 03:38.551 SO LISTEN UP, AND APPRECIATE SOUND. 03:38.551 --> 03:40.920 [APPLAUSE] >> JOINING ME NOW TO ANSWER YOUR 03:40.920 --> 03:42.989 QUESTIONS ABOUT SOUND ARE TWO SCIENTISTS. 03:42.989 --> 03:46.726 IN OUR POCATELLO STUDIO IS STEVE SHROPSHIRE, PROFESSOR OF PHYSICS 03:46.726 --> 03:47.560 AT IDAHO STATE UNIVERSITY. 03:47.560 --> 03:49.029 THANK YOU FOR JOINING US. 03:49.029 --> 03:51.765 >> THANK YOU FOR HAVING ME. 03:51.765 --> 03:56.569 >> AND JOINING ME HERE IN BOISE IS KATHRYN DEVINE, ASSISTANT 03:56.569 --> 03:58.405 PROFESSOR OF PHYSICS AT THE COLLEGE OF IDAHO. 03:58.405 --> 04:04.077 LET'S GO TO YOUR QUESTIONS. 04:04.077 --> 04:08.515 >> MY NAME IS JACK, AND I GO TO SHADOW HILLS ELEMENTARY, AND MY 04:08.515 --> 04:11.618 QUESTION IS, HOW ARE SOUNDS MADE? 04:11.618 --> 04:14.421 >> WHEN YOU MAKE A SOUND YOU'RE ACTUALLY GETTING A LITTLE BIT OF 04:14.421 --> 04:16.589 ENERGY TO THE AIR AROUND YOU. 04:16.589 --> 04:20.326 AND SO SOUND IS A WAVE, A COMPRESSION WAVE OF ALL THE MALL 04:20.326 --> 04:23.329 CIEWLS IN THE AIR, CARRYING THAT ENERGY FROM WHATEVER MADE THE 04:23.329 --> 04:25.331 SOUND, MY VOICE, ALL THE WAY TO YOUR EAR. 04:25.331 --> 04:29.336 SO IT'S A WAVE TRAVELING THROUGH THE AIR. 04:29.336 --> 04:31.504 >> MY NAME IS SHELBY. 04:31.504 --> 04:37.243 MY QUESTION IS, HOW FAST AND HOW FAR DOES SOUND TRAVEL? 04:37.243 --> 04:41.247 >> WELL, AT ROOM TEMPERATURE SOUND TRAVELS AT ABOUT 330 04:41.247 --> 04:42.449 METERS PER SECOND. 04:42.449 --> 04:47.654 THAT'S OVER 300 YARDS EVERY SECOND, SO IT'S QUITE FAST. 04:47.654 --> 04:52.025 AND SOUNDS CAN TRAVEL A GREAT DEAL OF DISTANCES. 04:52.025 --> 04:57.197 WHEN A VOLCANO NEAR INDONESIA EXPLODED BACK IN THE 1800s, 04:57.197 --> 05:01.034 THE SOUND WAS HEARD FOR HUNDREDS AND HUNDREDS OF MILES. 05:01.034 --> 05:02.502 AND THAT'S THROUGH THE AIR. 05:02.502 --> 05:06.239 SOUND ACTUALLY TRAVELS A LITTLE BIT BETTER THROUGH WATER. 05:06.239 --> 05:09.943 WE KNOW WHALES CAN COMMUNICATE WITH EACH OTHER OVER HUNDREDS OF 05:09.943 --> 05:12.779 MILES OF OCEAN. 05:12.779 --> 05:15.949 >> NOAH FROM DALTON ELEMENTARY WOULD LIKE TO KNOW, WHY DOES 05:15.949 --> 05:18.852 SOUND TRAVEL IN WAVES? 05:18.852 --> 05:23.423 >> WELL, A WAVE IS A DISTURBANCE IN SOMETHING. 05:23.423 --> 05:30.263 AND IF YOU PUSH ON SOMETHING, LIKE A TABLE, YOU EXPECT THE 05:30.263 --> 05:31.264 WHOLE TABLE TO MOVE. 05:31.264 --> 05:35.602 BUT WITH AIR OR WATER, WHEN YOU PUSH ON ONE PART OF IT, IT TAKES 05:35.602 --> 05:39.706 A WHILE FOR THAT DISTURBANCE TO MOVE, TO GET A BUNCH OF OTHER 05:39.706 --> 05:39.906 STUFF. 05:39.906 --> 05:42.709 IT'S LIKE WHEN YOU SPLASH SOMETHING IN WATER, THROW A ROCK 05:42.709 --> 05:46.279 IN WATER, ALL THE WATER DOESN'T MOVE AT ONCE. 05:46.279 --> 05:48.281 BECAUSE IT'S KIND OF FLUID. 05:48.281 --> 05:51.251 YOU'LL HAVE A DISTURBANCE TRAVELING OUTWARDS IN A WAVE. 05:51.251 --> 05:55.121 WE SEE THAT IN WATER QUITE OFTEN, AND THAT'S REALLY WHAT 05:55.121 --> 05:57.557 HAPPENED -- WHAT IS HAPPENING IN AIR TOO, WITH THE SOUND WE HEAR, 05:57.557 --> 06:00.593 WE JUST DON'T SEE THE AIR MOVING IN THE SAME WAY. 06:00.593 --> 06:03.196 BUT IT DOES. 06:03.196 --> 06:08.601 >> HI, MY NAME IS ALYSSA, AND I GO TO WHITMAN ELEMENTARY SCHOOL 06:08.601 --> 06:08.868 LEWISTON. 06:08.868 --> 06:14.040 MY QUESTION IS, HOW DOES SOUND TRAVEL THROUGH SPACE? 06:14.040 --> 06:17.844 >> SOUND JUST LIKE YOU'VE JUST SAID, WHERE YOU HAVE ONE KIND OF 06:17.844 --> 06:22.048 PERSON PART OF THE AIR, ONE MOLECULE COMMUNICATING THAT WAVE 06:22.048 --> 06:25.318 TO THE NEXT ONE, THAT SAME THING HAPPENS IN SPACE. 06:25.318 --> 06:28.855 THE THING THAT'S DIFFERENT IS THAT OUT IN SPACE, THE DENSITY 06:28.855 --> 06:34.094 OF THE AIR IS A LOT LOWER, SO THE MOLECULES ARE FARTHER APART. 06:34.094 --> 06:38.431 AND SO SOUND CAN STILL TRAVEL IN SPACE AS LONG AS THERE IS ANY 06:38.431 --> 06:41.534 GAS OR MOLECULES OR ANYTHING THERE TO COMMUNICATE F THERE 06:41.534 --> 06:44.337 WASN'T ANYTHING THERE, SOUND WOULDN'T BE ABLE TO TRAVEL. 06:44.337 --> 06:49.275 SO THERE DOES HAVE TO BE A GAS CLOUD OR SOME MOL YOU'LL OUT 06:49.275 --> 06:53.279 THERE THAT CAN COMMUNICATE THE ENERGY TO THE NEXT ONE. 06:53.279 --> 06:58.385 >> MY NAME IS BRADEN, AND I GO TO LENA IN MOSCO, IDAHO. 06:58.385 --> 07:02.655 MY QUESTION IS, WHY DO A TRUMPET AND A SAXOPHONE SOUND DIFFERENT, 07:02.655 --> 07:07.027 EVEN WHEN THEY ARE PLAYING THE SAME NOTE AT THE SAME VOLUME? 07:07.027 --> 07:10.597 >> YOU'VE PROBABLY NOTICED LONGER AND BIGGER INSTRUMENTS 07:10.597 --> 07:14.601 MAKE LOWER PITCHED SOUNDS, LOWER NOTES, AND SHORTER AND SMALLER 07:14.601 --> 07:16.503 INSTRUMENTS MAKE HIGHER PITCHED SOUNDS. 07:16.503 --> 07:20.607 THAT HAS TO DO WITH HOW THE SOUND RESONATES IN THESE 07:20.607 --> 07:21.675 DIFFERENT INSTRUMENTS. 07:21.675 --> 07:25.078 TO ILLUSTRATE I HAVE SOME LITTLE PIPES HERE. 07:25.078 --> 07:27.881 AND THIS ONE IS CUT A LITTLE LONGER THAN THE OTHERS, AND WHEN 07:27.881 --> 07:31.718 I WHACK IT ON MY PALM, I GET A C NOTE. 07:31.718 --> 07:40.093 AND WITH THE BLACK ONE, THAT'S A D, ORANGE ONE, E, F, G, AND AN 07:40.093 --> 07:40.493 A. 07:40.493 --> 07:44.964 YOU CAN SEE THE SHORTER THE PIPE THE HIGHER THE PITCH. 07:44.964 --> 07:49.803 I'VE GOT SOMETHING YOU CAN DO AT HOME WITH A LITTLE PLASTIC 07:49.803 --> 07:50.070 STRAW. 07:50.070 --> 07:54.274 IF YOU TAKE A STRAW AND YOU CUT LITTLE GROOVES IN IT, SHAPED 07:54.274 --> 07:58.578 LIKE TRIANGLES, LIKE I HAVE HERE, AND YOU BITE IT DOWN WITH 07:58.578 --> 08:02.649 YOUR TEETH, YOU CAN MAKE A LITTLE REED. 08:02.649 --> 08:04.751 A LOT OF INSTRUMENTS WORK ON REEDS. 08:04.751 --> 08:09.289 WHEN YOU BLOW AIR BETWEEN THE REEDS, THEY VIBRATE. 08:09.289 --> 08:12.759 AND THE LONGER THE INSTRUMENT, THE LOWER THE PITCH OF SOUND 08:12.759 --> 08:14.661 WILL RESONATE IN THAT. 08:14.661 --> 08:23.236 AND SO IF I JUST BLOW ON THIS STRAW, WE GET A NOTE, AND IF I 08:23.236 --> 08:26.573 TAKE TWO STRAW AND STICK THEM TOGETHER, I'LL GET A LOWER 08:26.573 --> 08:34.347 PITCH. 08:34.347 --> 08:39.953 AND I CAN EVEN CHANGE THE LENGTH OF THE PIPE AND GET DIFFERENT 08:39.953 --> 08:54.334 PITCHES FROM THE SAME STRAW. 08:54.334 --> 08:57.570 * >> THAT'S GREAT. 08:57.570 --> 08:58.271 [LAUGHTER] OK. 08:58.271 --> 09:04.844 LET'S GO BACK TO THE QUESTIONS. 09:04.844 --> 09:10.650 >> HI, MY NAME IS SARAH, I GO TO ST. MARY'S ELEMENTARY, AND MY 09:10.650 --> 09:16.389 QUESTION IS, WHY -- HOW DOES SOUND TRAVEL BETTER THROUGH 09:16.389 --> 09:16.923 WATER? 09:16.923 --> 09:18.124 >> WELL, WATER IS DENSER. 09:18.124 --> 09:21.761 THERE'S MORE STUFF THERE IN A SMALLER SPACE, AND THE MOLECULES 09:21.761 --> 09:25.865 ARE CLOSER TOGETHER, AND SO WHEN SOME MOLECULES GET THE ENERGY 09:25.865 --> 09:30.036 FROM THE SOUND, FROM THE DISTURBANCE, THEY WILL COLLIDE 09:30.036 --> 09:34.140 WITH OTHER MOLECULES SOONER, AND MORE RAPIDLY. 09:34.140 --> 09:38.778 AND ALSO WATER IS A LITTLE MORE ELASTIC THAN AIR, AND YOU CAN 09:38.778 --> 09:41.581 THINK OF IT AS BEING STIFFER IN A WAY. 09:41.581 --> 09:46.052 AND ALL THAT CONTRIBUTES TO MAKING THE SOUND TRAVEL BETTER 09:46.052 --> 09:47.787 AND FARTHER. 09:47.787 --> 09:50.623 >> ONE OF THE THINGS I'VE ALWAYS FOUND INTERESTING, I DON'T KNOW 09:50.623 --> 09:55.161 ABOUT THE AUDIENCE OUT THERE, BUT I ALWAYS TRIED TO TALK TO MY 09:55.161 --> 09:56.796 BROTHER UNDER WATER WHEN WE WERE KIDS. 09:56.796 --> 09:58.631 IT WOULD ALWAYS SOUND WEIRD. 09:58.631 --> 10:01.067 THAT'S BECAUSE WATER TRANSMITS DIFFERENT FREQUENCIES AT 10:01.067 --> 10:06.106 DIFFERENT SPEEDS, SO OUR EARS ARE USED TO HEARING SOUNDS IN 10:06.106 --> 10:06.373 AIR. 10:06.373 --> 10:09.542 BUT EVEN THOUGH WATER CAN TRANSMIT SOUNDS FASTER BETTER, 10:09.542 --> 10:14.381 IT DOESN'T TRANSMIT IT IN A WAY OUR EARS ARE USED TO HEARING, 10:14.381 --> 10:17.817 WHICH IS WHY IT SOUNDS GAR ABOUTED. 10:17.817 --> 10:22.255 >> IS THERE AN OBJECT SO THICK OR SO STRONG THAT SOUND CAN'T 10:22.255 --> 10:25.091 PASS THROUGH IT? 10:25.091 --> 10:29.396 >> IT KIND OF DEPENDS, I GUESS, ON HOW YOU THINK ABOUT IT. 10:29.396 --> 10:33.633 SOUND IS ENERGY TRAVELING, IT'S AN ENERGY WAVE, SO THE LOUDER 10:33.633 --> 10:36.102 THE SOUND, THE MORE ENERGY YOU'RE PUTTING IN, THE THICKER 10:36.102 --> 10:38.938 SOMETHING WOULD HAVE TO BE TO STOP THE ENERGY FROM TRAVELING 10:38.938 --> 10:41.141 THROUGH IT. 10:41.141 --> 10:44.110 AND SO, FOR EXAMPLE, IF I WAS WHISPERING AND YOU HAD JUST A 10:44.110 --> 10:46.046 WALL, THAT WOULD BE ENOUGH TO STOP THE SOUND FROM TRAVELING 10:46.046 --> 10:46.546 THROUGH IT. 10:46.546 --> 10:49.649 BUT IF I WAS SHOUTING, MAYBE A WALL WOULDN'T BE ENOUGH AND IT 10:49.649 --> 10:51.117 WOULD HAVE TO BE THICKER. 10:51.117 --> 10:54.387 IT DEPENDS ON HOW LOUD THE SOUND IS OR HOW THICK SOMETHING WOULD 10:54.387 --> 10:56.056 HAVE TO BE TO BLOCK THE SOUND. 10:56.056 --> 10:58.725 >> HI, MY NAME IS SEAN, AND I'M FROM ILLINOIS. 10:58.725 --> 11:04.264 MY QUESTION IS, HOW FAR CAN THE FIRE ALARM SOUND POSSIBLY 11:04.264 --> 11:04.798 TRAVEL? 11:04.798 --> 11:07.334 >> DEPENDS ON THE FIRE ALARM AND IT DEPENDS ON WHAT'S IN THE WAY 11:07.334 --> 11:08.535 OF THE FIRE ALARM. 11:08.535 --> 11:12.505 AGAIN, THE THINGS THAT CAN MAKE SOUND TRAVEL FARTHER IS THE 11:12.505 --> 11:15.375 AMOUNT OF ENERGY THAT IS BEING PRODUCED OR THAT THE SOUND IS 11:15.375 --> 11:16.076 GIVING OUT. 11:16.076 --> 11:19.079 AND SO IF YOU -- IT DEPENDS ON THE VOLUME OF YOUR FIRE ALARM 11:19.079 --> 11:20.747 AND THE FIRE ALARM. 11:20.747 --> 11:23.650 SOMETIMES BIG APARTMENT BUILDINGS HAVE VERY HIGH ENERGY 11:23.650 --> 11:26.519 LOUD FIRE ALARMS, LIKE IN A SCHOOL BUILDING BECAUSE THEY 11:26.519 --> 11:29.456 HAVE TO BE ABLE TO HEARD TROUT THE WHOLE BUILDING, VERSUS THE 11:29.456 --> 11:33.126 FIRE ALARM IN MY BEDROOM ISN'T AS LOUD, IT PRODUCES LESS 11:33.126 --> 11:33.460 ENERGY. 11:33.460 --> 11:36.363 SO YOU WOULDN'T BE ABLE TO HEAR IT PROBABLY AS FAR AS MY 11:36.363 --> 11:37.263 NEIGHBOR'S HOUSE. 11:37.263 --> 11:40.567 BUT IF A FIRE ALARM IN A BIG BUILDING GOES OFF YOU CAN HEAR 11:40.567 --> 11:41.768 IT FARTHER AWAY. 11:41.768 --> 11:45.905 IT COMES DOWN TO HOW MUCH ENERGY THE SOUND IS GIVING OFF, HOW 11:45.905 --> 11:51.411 MUCH ENERGY IS GOING ON AT THE SOURCE. 11:51.411 --> 11:54.748 >> DID YOU KNOW THAT DOLPHINS ON COULD HEAR SOUNDS UNDER WATER 11:54.748 --> 11:56.282 FROM 15 MILES AWAY? 11:56.282 --> 11:58.718 SNAKES ON THE OTHER HAND HAVE NO EARS. 11:58.718 --> 12:06.326 THEY SENSE SOUND WITH THEIR TONGUES. 12:06.326 --> 12:10.263 CAMERON AT DOLL TON ELEMENTARY WOULD LIKE TO KNOW, HOW MANY 12:10.263 --> 12:13.333 ANIMALS USE SOUND TO NAVIGATE THEIR WAY AROUND THE WORLD? 12:13.333 --> 12:14.501 >> LOTS OF THEM. 12:14.501 --> 12:20.273 WE KNOW THAT BATS USE SOUND TO NAVIGATE, AND TO HUNT. 12:20.273 --> 12:24.010 THEY ACTUALLY LISTEN VERY CLOSELY TO THE SOUND, THE ECHOS 12:24.010 --> 12:28.882 OF THE SOUND THAT BOUNCE OFF OF THE INSECTS AND OBJECTS AROUND 12:28.882 --> 12:29.115 THEM. 12:29.115 --> 12:32.185 ALSO A LOT OF THINGS THAT LIVE IN WATER. 12:32.185 --> 12:36.089 SINCE SOUND TRAVELS SO WELL THROUGH WATER, A LOT OF FISH AND 12:36.089 --> 12:40.360 OCEAN CREATURES USE SOUND TO NAVIGATE, AND ALSO TO HUNT. 12:40.360 --> 12:43.663 AND THERE'S EVEN SOME BIRDS THAT DO THAT TOO. 12:43.663 --> 12:47.667 >> MA TILDA, ALSO FROM DALTON GARDENS ELEMENTARY WOULD LIKE TO 12:47.667 --> 12:50.103 KNOW, WHY CAN'T YOU SEE SOUND WAVES? 12:50.103 --> 12:55.475 >> SO A SOUND WAVE IS A LITTLE TINY MOLECULE THAT YOU CAN'T 12:55.475 --> 12:55.742 SEE. 12:55.742 --> 12:58.978 SO I GUESS IT GOES DOWN TO THE FACT YOU CAN'T SEE THE AIR, EVEN 12:58.978 --> 13:01.781 THOUGH THERE IS STUFF IN THE AIR BETWEEN US, YOU CAN'T SEE IT. 13:01.781 --> 13:03.983 THERE'S NOTHING THAT I CAN SEE HERE. 13:03.983 --> 13:08.254 BUT THAT'S THIS AIR IN FRONT OF ME IS WHAT IS MAKING THE SOUND 13:08.254 --> 13:09.155 WAVE PROPAGATE THROUGH. 13:09.155 --> 13:12.225 I SUPPOSE IF YOU HAD AMAZING EYES AND COULD SEE THE MOLECULES 13:12.225 --> 13:14.894 MOVING, YOU WOULD BE ABLE TO SEE THE SOUND WAVE, BUT WE CAN'T 13:14.894 --> 13:17.630 ACTUALLY SEE THE SMALL, SMALL THINGS IN THE AIR THAT ARE 13:17.630 --> 13:20.333 TRANSMITTING THE SOUND WAVE ALONG THE AIR. 13:20.333 --> 13:25.905 >> IF I COULD JUMP IN, THERE IS -- IF YOU EVER WATCHED 13:25.905 --> 13:31.277 EXPLOSIONS, OR VERY, VERY LOUD NOISES, YOU SEE IT A LOT WITH 13:31.277 --> 13:32.812 ARTILLERY, SAY WITH THE ARMY. 13:32.812 --> 13:37.017 YOU CAN ACTUALLY SEE WHAT LOOKS LIKE A SOUND WAVE, BUT WHAT 13:37.017 --> 13:40.653 YOU'RE SEEING IS YOU HAVE SO MUCH ENERGY BEING DEPOSITED IN 13:40.653 --> 13:44.290 THE AIR, THE WATER IN THE AIR CONDENSES OUT INTO LITTLE WATER 13:44.290 --> 13:47.827 DROP LET'S, AND YOU'LL ACTUALLY SEE WHAT LOOKS LIKE A WAVE 13:47.827 --> 13:51.031 TRAVELING THROUGH THE AIR, BUT IT'S REALLY THE WATER CONDENSING 13:51.031 --> 13:54.000 OUT BRIEFLY AS THE SOUND WAVE GOES THROUGH IT. 13:54.000 --> 13:56.936 SO YOU'RE NOT ACTUALLY SEEING THE AIR, BUT YOU'RE SEEING WATER 13:56.936 --> 14:00.940 THAT'S BEING IN A WAY DRIVEN OUT OF THE AIR BRIEFLY BY THE 14:00.940 --> 14:02.308 INTENSE SOUND. 14:02.308 --> 14:07.047 >> HI, MY NAME IS ANNE. 14:07.047 --> 14:10.984 MY QUESTION IS, HOW FAST DO YOU HAVE TO GO TO BREAK THE SOUND 14:10.984 --> 14:11.317 BARRIER? 14:11.317 --> 14:15.889 >> THE SPEED OF SOUND IS 330 METERS PER SECOND. 14:15.889 --> 14:18.324 HERE AT ROOM TEMPERATURE. 14:18.324 --> 14:21.361 SO THAT'S ABOUT HOW FAST YOU'D HAVE TO GO. 14:21.361 --> 14:26.066 ABOUT 330 YARDS EVERY SECOND. 14:26.066 --> 14:26.433 >> HI. 14:26.433 --> 14:30.437 MY NAME IS McKENNA, I GO TO RUSSELL SCHOOL IN MOSCO. 14:30.437 --> 14:34.908 MY QUESTION IS, WHY IS THE SPEED OF LIGHT FASTER THAN THE SPEED 14:34.908 --> 14:36.009 OF SOUND? 14:36.009 --> 14:38.511 >> THAT'S ACTUALLY A REALLY INTERESTING QUESTION. 14:38.511 --> 14:42.182 LIGHT WAVES AND SOUND WAVES ARE A PRETTY DIFFERENT AND VERY 14:42.182 --> 14:42.916 FUNDAMENTAL WAY. 14:42.916 --> 14:47.253 SO SOUND WAVES REQUIRE THAT YOU HAVE AIR OR GAS OR SOMETHING 14:47.253 --> 14:50.557 THAT WILL TRANSMIT, SOME MOLECULE THAT WILL TRANSMIT THE 14:50.557 --> 14:53.927 WAVE, BECAUSE THEY HAVE TO PASS THE SIGNAL TO THE NEXT MOLECULE 14:53.927 --> 14:55.662 TO PASS THE WAVE ALONG. 14:55.662 --> 14:59.232 LIGHT, ON THE OTHER HAND, IF YOU HAD A VACUUM WHICH IS A TOTAL 14:59.232 --> 15:02.235 ABSENCE OF ANYTHING, TOTALLY EMPTY SPACE, YOU CAN STILL HAVE 15:02.235 --> 15:07.040 A LIGHT WAVE TRAVEL THROUGH IT BECAUSE LIGHTS -- LIGHT TRAVELS 15:07.040 --> 15:10.410 THROUGH A FIELD, IT DOESN'T REQUIRE HAVING MOLECULES. 15:10.410 --> 15:14.314 SO KIND OF OFF TOPIC, BUT THEY'RE VERY DIFFERENT AND VERY 15:14.314 --> 15:14.781 INTERESTING. 15:14.781 --> 15:18.518 THE SPEED THEN SINCE LIGHT DOESN'T DEPEND ON MOLECULES 15:18.518 --> 15:21.988 COMPRESSING INTO EACH OTHER TO TRANSMIT THE WAVE ALONG, THEY 15:21.988 --> 15:28.061 CAN TRAVEL FASTER, SO IT HAS TO DO WITH HOW THE 15:28.061 --> 15:28.895 WAVE -- PROPAGATES THROUGH SPACE. 15:28.895 --> 15:32.098 SO IT JUST A VERY DIFFERENT WAY OF HAVING THE ENERGY TRAVEL 15:32.098 --> 15:36.169 THROUGH SPACE THAT MAKES IT SO LIGHT CAN GO FASTER. 15:36.169 --> 15:38.805 >> JACK FROM DALTON ELEMENTARY WOULD LIKE TO KNOW, HOW DOES 15:38.805 --> 15:41.641 YOUR VOICE ECHO? 15:41.641 --> 15:44.711 >> YOUR VOICE ECHOS WHEN THE SOUND BOUNCES OFF OF SOMETHING 15:44.711 --> 15:45.011 ELSE. 15:45.011 --> 15:48.715 IT'S BASICALLY A REFLECTION OF THE SOUND. 15:48.715 --> 15:52.452 AGAIN, USING THE ANALOGY OF THROWING A ROCK INTO WATER, IF 15:52.452 --> 15:57.957 YOU'VE GOT LIKE A STIFF BANK, A CONCRETE POND, YOU'LL SEAT WATER 15:57.957 --> 16:00.493 RIPPLES HITTING THE EDGE OF THE POUND EVER POND AND BREAKING 16:00.493 --> 16:00.860 BACK. 16:00.860 --> 16:04.197 THE SAME THINGS HAPPEN WITH YOUR ECHO, AND YOU CAN HEAR THE SOUND 16:04.197 --> 16:06.199 BOUNCING OFF OF SOMETHING. 16:06.199 --> 16:08.702 SO IT'S LIKE THE SOUND WAVE IS MOVING AND HITS SOMETHING AND 16:08.702 --> 16:09.869 BOUNCES RIGHT BACK TOWARDS YOU. 16:09.869 --> 16:12.572 SO YOU CAN HEAR YOUR OWN VOICE AGAIN. 16:12.572 --> 16:14.074 OR OTHER SOUNDS, TOO. 16:14.074 --> 16:17.243 SO IT'S BASICALLY A BOUNCING OFF THE SOUND OFF SOMETHING ELSE. 16:17.243 --> 16:26.252 >> MY NAME IS ALYSSA, HOW DOES SOUND TRAVEL TO iPOD TO 16:26.252 --> 16:26.619 HEADPHONES? 16:26.619 --> 16:29.155 >> IT'S NOT SOUND TRAVELING THROUGH THE CORD, IT'S BASICALLY 16:29.155 --> 16:30.323 AN ELECTRICAL SIGNAL. 16:30.323 --> 16:34.594 AND THE ELECTRICAL SIGNAL GOES TO A SPEAKER, AND THE ENERGY OF 16:34.594 --> 16:39.599 THE ELECTRICITY MAKES A LITTLE MEMBRANE THERE VIBRATE. 16:39.599 --> 16:42.335 AND SOMETHING VIBRATES, IT WILL MOVE THE AIR AROUND IT. 16:42.335 --> 16:48.541 SO THE SOUND IS ONLY EXISTS THERE AT THE SPEAKER INSIDE YOUR 16:48.541 --> 16:48.808 EAR. 16:48.808 --> 16:51.644 IT DOESN'T EXIST INSIDE THE CORD. 16:51.644 --> 16:52.445 THAT'S ELECTRICITY. 16:52.445 --> 16:57.050 IT CARRIES THAT INFORMATION THAT BASICALLY MAKES THE SPEAKER 16:57.050 --> 16:57.384 MOVE. 16:57.384 --> 17:00.387 >> A LOT OF YOU HAD QUESTIONS ABOUT SOUND AND HEARING. 17:00.387 --> 17:04.391 SO LET'S LEARN A LITTLE BIT MORE ABOUT HOW OUR EARS AND BRAINS 17:04.391 --> 17:06.026 HEAR SOUND. 17:06.026 --> 17:09.396 >> WHEN YOU MAKE A SOUND, YOU CREATE ENERGY IN THE FORM OF 17:09.396 --> 17:10.964 SOUND WAVES. 17:10.964 --> 17:15.969 A LOUD SOUND HAS TALLER WAVES THAN A SOFT ONE. 17:15.969 --> 17:18.872 THESE WAVES EVENTUALLY ENTER YOUR EARS. 17:18.872 --> 17:21.041 THE SOUND WAVES TRAVEL DOWN THE EAR CANAL. 17:21.041 --> 17:24.978 THE EAR CAN AM IS ABOUT AN INCH LONG, AND AT ITS END IS A THIN 17:24.978 --> 17:27.047 PIECE OF SKIN CALLED THE EARDRUM. 17:27.047 --> 17:30.884 THE EARDRUM IS STRETCHED TIGHT, JUST LIKE THE TOP OF A DRUM. 17:30.884 --> 17:35.055 WHEN THE SOUND WAVES HIT THE EARDRUM, IT BEGINS TO VIBRATE. 17:35.055 --> 17:38.625 THAT VIBRATION MAKES THREE TINY BONES IN YOUR MIDDLE EAR BEGIN 17:38.625 --> 17:40.060 TO MOVE. 17:40.060 --> 17:43.797 THESE THREE LITTLE BONES ARE KNOWN AS THE HAMMER, ANVIL, AND 17:43.797 --> 17:47.434 STIR UP, BECAUSE THAT'S WHAT THEY KIND OF LOOK LIKE. 17:47.434 --> 17:50.704 THEY FEEL THE BONES TRANSMIT OR MOVE THE SOUND WAVES ALONG TO 17:50.704 --> 17:51.638 THE INBOUNDER EAR. 17:51.638 --> 17:55.275 THEY ALSO INCREASE THE FORCE OF SOUND WAVES. 17:55.275 --> 18:01.214 THEY MOVE INTO A SNAIL SHAPED STRUCTURE CALLED THE COKE LEE A. 18:01.214 --> 18:05.952 THEY'RE FILLED WITH FLUID AND 17,000 HAIRLIKE TISSUES. 18:05.952 --> 18:09.189 SOUND WAVES MOVE THROUGH THE FLUID AND THE HAIR BENDS. 18:09.189 --> 18:12.225 SOMEHOW THE MOVEMENT OF THOSE HAIRS STIMULATES THE 30,000 18:12.225 --> 18:15.061 NERVE FIBERS. 18:15.061 --> 18:17.764 THAT NERVE CARRIES THE SIGNAL TO THE BRAIN AND THE BRAIN FIGURES 18:17.764 --> 18:19.332 OUT WHAT THE SOUND IS. 18:19.332 --> 18:22.235 YOU NEED TWO EARS TO FIGURE OUT WHERE A SOUND COMES FROM. 18:22.235 --> 18:25.572 YOUR BRAIN FIGURES THE TERRENCE BETWEEN THE TWO SOUND LEVELS, 18:25.572 --> 18:28.508 AND CALCULATES THE DIRECTION OF THE SOUND. 18:28.508 --> 18:32.145 IT'S IMPORTANT TO PROTECT YOUR HEARING FROM LOUD SOUNDS. 18:32.145 --> 18:34.681 MUSCLES IN THE MIDDLE EAR PROTECT THE EAR BY STIFFENING 18:34.681 --> 18:38.485 THE EARDRUM, OR BY MOVING THE STIR UP BONE AWAY FROM THE INNER 18:38.485 --> 18:38.785 EAR. 18:38.785 --> 18:43.156 BUT SUDDEN LOUD SOUNDS CAN BREAK THE EARDRUM OR CAUSE OTHER 18:43.156 --> 18:49.095 DAMAGE AND CONTINUED LOUD SOUNDS CAN DAMAGE THE TINY HAIRS IN THE 18:49.095 --> 18:49.429 COCHLEA. 18:49.429 --> 18:52.632 BE SURE TO WEAR HEARING PROTECTION IF YOU'RE GOING TO BE 18:52.632 --> 18:55.435 AROUND LOUD NOISES, AND TURN THE VOLUME DOWN ON YOUR HEADPHONES. 18:55.435 --> 18:59.305 BECAUSE ONCE YOUR HEARING IS DAMAGE THE, IT CAN'T BE MADE ALL 18:59.305 --> 18:59.572 BETTER. 18:59.572 --> 19:01.841 ABOUT 200,000 AMERICANS ARE DEAF. 19:01.841 --> 19:04.210 THAT MEANS THEY CAN'T HEAR ANYTHING. 19:04.210 --> 19:07.547 ANOTHER 3 MILLION HAVE SEVERE HEARING PROBLEMS. 19:07.547 --> 19:10.950 SOME USE HEARING AIDS TO AMPLIFY OR INCREASE THE STRENGTH OF 19:10.950 --> 19:13.386 SOUND WAVES SO THEY CAN HEAR BETTER. 19:13.386 --> 19:15.021 OTHERS HAVE A COCHLEAR IMPLANT. 19:15.021 --> 19:18.758 THAT'S WHERE A SMALL MICROPHONE HELPS TRANSMIT SOUND TO THE 19:18.758 --> 19:19.292 INNER EAR. 19:19.292 --> 19:22.662 INDIVIDUALS WHO ARE DEAF OR HARD OF HEARING SOMETIMES USE SIGN 19:22.662 --> 19:24.030 LANGUAGE TO COMMUNICATE. 19:24.030 --> 19:26.232 OTHERS CAN READ LIPS. 19:26.232 --> 19:29.235 COMMUNICATING, WHETHER IT'S WITH YOUR EARS OR YOUR HANDS, IS 19:29.235 --> 19:30.570 ESSENTIAL TO LIFE. 19:30.570 --> 19:36.476 BY THE WAY, YOUR EAR DOES ONE OTHER THING -- REMEMBER THE 19:36.476 --> 19:36.710 COCHLEA? 19:36.710 --> 19:39.979 MOVEMENT OF THE FLUID INSIDE THAT TELLS THE BRAIN ABOUT YOUR 19:39.979 --> 19:40.880 BODY POSITION. 19:40.880 --> 19:43.950 THAT WAY YOU CAN TELL UP FROM DOWN, EVEN WITH YOUR EYES 19:43.950 --> 19:44.217 CLOSED. 19:44.217 --> 19:47.987 WHEN YOU SPIN AROUND, THE FLUID IN THE COCHLEA SPINS TOO, AND 19:47.987 --> 19:55.061 THAT EXPLAINS WHY YOU FEEL DIZZY. 19:55.061 --> 19:59.099 >> HI, MY NAME IS JOY, I GO TO WHITMAN ELEMENTARY SCHOOL. 19:59.099 --> 20:02.502 MY QUESTION IS, HOW DO YOU HEAR SOUNDS IN YOUR EARS? 20:02.502 --> 20:02.736 >> OK. 20:02.736 --> 20:06.339 SO YOUR EARS I THINK YOU HAVE PROBABLY NOTICED, YOUR EARS HAVE 20:06.339 --> 20:08.808 A LITTLE HOLE IN THEM, THERE'S A LITTLE ENTRANCE THERE. 20:08.808 --> 20:12.078 SO THE SOUND WAVES COME IN AND THEY HIT THAT ENTRANCE TO YOUR 20:12.078 --> 20:17.017 EAR, AND THEN WHAT -- YOU HAVE LITTLE HAIRS IN YOUR EAR THAT 20:17.017 --> 20:20.720 RESPOND TO THE WAVES, SO JUST KIND OF LIKE SEAWEED IN A POND 20:20.720 --> 20:23.890 THAT'S GETTING MOVED AROUND BY THE WAVES IN THE WATER, THE 20:23.890 --> 20:29.129 SOUND WAVE MOVES THESE LITTLE DETECTORS IN YOUR EAR AROUND, 20:29.129 --> 20:32.465 AND THOSE TRANSMIT A SIGNAL TO THE NERVOUS SYSTEM THAT 20:32.465 --> 20:34.467 EVENTUALLY COMMUNICATES THAT INFORMATION TO YOUR BRAIN AND 20:34.467 --> 20:37.037 TELLS YOU WHAT KIND OF SOUND YOU'RE HEARING. 20:37.037 --> 20:41.007 >> MY NAME IS KENDALL, I GO TO CAMELOT ELEMENTARY, AND MY 20:41.007 --> 20:45.679 QUESTION IS, WHY DO LOUD NOISES HURT OUR EARS? 20:45.679 --> 20:49.649 >> AGAIN, WITH THE LITTLE HAIRS IN YOUR EARS, A LOUD SOUND, THAT 20:49.649 --> 20:54.320 WOULD BE LIKE A WAVE THAT'S TOO BIG IN THE EXPOND SMASHES ALL 20:54.320 --> 20:55.488 THE SEAWEED DOWN. 20:55.488 --> 21:00.260 SO IF YOU HAVE A WAVE THAT'S TOO MUCH ENERGY COMING TO YOUR EAR, 21:00.260 --> 21:05.799 IT CAN HURT ALL THOSE LITTLE DETECTORS BECAUSE THEY'RE NOT 21:05.799 --> 21:08.868 CLIPPED, ARE -- THEY'RE NOT EQUIPPED OR THEY'RE NOT READY 21:08.868 --> 21:09.903 FOR ALL THAT ENERGY. 21:09.903 --> 21:13.173 IT CAN ACTUALLY HURT THE DETECTORS IN YOUR EAR, AND THEN 21:13.173 --> 21:16.910 IF YOU HAVE EVER HEARD A REALLY LOUD NOISE THAT CAUSES RINGING 21:16.910 --> 21:21.381 IN YOUR EAR, THE INABILITY TO HEAR AS WELL THAN BEFORE YOU 21:21.381 --> 21:24.351 HEARD THE LOUD NOISE, IT'S BECAUSE YOU DAMAGED THE 21:24.351 --> 21:25.919 DETECTORS IN YOUR EAR. 21:25.919 --> 21:28.288 >> HANNAH WOULD LIKE TO KNOW IF THERE'S A CLASSROOM FULL OF KIDS 21:28.288 --> 21:30.924 AND THE TEACHER WAS SPEAKING, WOULD THE KIDS ALL HEAR THE 21:30.924 --> 21:33.093 SOUND AT THE SAME TIME? 21:33.093 --> 21:33.360 >> NO. 21:33.360 --> 21:34.728 THEY WOULDN'T. 21:34.728 --> 21:39.132 BUT IN A CLASSROOM, IT'S ENOUGH SPACE SO THAT AGAIN, SOUND 21:39.132 --> 21:44.037 TRAVELS AT ABOUT 330 METERS PER SECOND, THE TYPICAL CLASSROOM IS 21:44.037 --> 21:48.208 ONLY MAYBE A DOZEN METERS, MAYBE AT MOST 15 METERS LONG. 21:48.208 --> 21:54.014 AND SO YOU'RE TALKING ABOUT TINY FRACTIONS OF A SECOND DIFFERENCE 21:54.014 --> 21:56.750 BETWEEN WHEN SOMEONE CLOSE TO THE TEACHER CAN HEAR AND SOMEONE 21:56.750 --> 21:57.150 FAR AWAY. 21:57.150 --> 22:00.487 IF YOU WANT TO BE VERY PICKY, YES, THEY'LL HEAR IT AT 22:00.487 --> 22:04.257 DIFFERENT TIMES, BUT IT WILL BE SO QUICK, NO ONE REALLY WILL 22:04.257 --> 22:04.724 NOTICE. 22:04.724 --> 22:10.630 >> YOU COULD NOTICE IT IF YOU WERE IN A MUCH LARGER SPACE. 22:10.630 --> 22:13.733 SO YOU'VE PROBABLY SEEN THIS WHEN YOU'VE WATCHED FIREWORKS, 22:13.733 --> 22:16.369 WHERE FIREWORKS, IF YOU'RE VERY CLOSE TO WHERE THE FIREWORKS ARE 22:16.369 --> 22:19.906 GOING OFF YOU SEE THE EXPLOSION AT THE SAME TIME YOU HEAR THE 22:19.906 --> 22:20.106 BOOM. 22:20.106 --> 22:23.009 IF YOU'RE FARTHER AWAY, AGAIN, YOU THAN GET SEVERAL HUNDRED 22:23.009 --> 22:25.712 FEET AWAY FROM THE FIREWORKS AND STILL BE ABLE TO SEE THEM, THE 22:25.712 --> 22:28.014 PEOPLE CLOSER TO THE FIREWORKS ARE HEARING THEM SOONER THAN YOU 22:28.014 --> 22:28.281 ARE. 22:28.281 --> 22:30.717 THAT'S HOW YOU GET THAT LAG BETWEEN WHEN YOU SEE THEM AND 22:30.717 --> 22:32.552 WHEN YOU HEAR THE EXPLOSION. 22:32.552 --> 22:37.290 IT COULD BE OVER A LARGE DISTANCES TO NOTICE THAT EFFECT. 22:37.290 --> 22:41.394 >> GABE WOULD LIKE TO KNOW, WHAT IS ULTRASOUND? 22:41.394 --> 22:43.563 >> SO ULTRASOUND IS SOMETHING THAT I THINK A LOT OF PEOPLE 22:43.563 --> 22:47.000 HEAR ABOUT IN MEDICINE IN TERMS OF BEING ABLE TO GET AN 22:47.000 --> 22:47.567 ULTRASOUND IMAGE. 22:47.567 --> 22:51.204 THAT'S THE TECHNIQUE OF USING SOUND, SINCE SOUND WAVES TRAVEL 22:51.204 --> 22:54.941 THROUGH MEDIUM, TO USE SOUND TO BOUNCE OFF AN OBJECT LIKE INSIDE 22:54.941 --> 22:58.978 THE HUMAN BODY, SO YOU CAN PUT AN ULTRASOUND MACHINE ON SOME OF 22:58.978 --> 23:02.315 THESE ABDOMEN AND SEE THEM INSIDE THEM BECAUSE THE SOUND 23:02.315 --> 23:05.218 WAVES COMES THROUGH, INTERACT WITH SOMETHING DENSER THAN 23:05.218 --> 23:07.787 SOMETHING IN THE REST OF THE BODY AND REFLECTS BACK OUT AND 23:07.787 --> 23:12.625 SO THEN THE DETECTOR CAN USE THOSE IMAGES TO MAKE A PICTURE. 23:12.625 --> 23:16.096 >> ELLIE WOULD LIKE TO KNOW HOW FAR CAN SOUND TRAVEL? 23:16.096 --> 23:18.798 >> THIS DEPENDS ON HOW LOUD THE ORIGINAL SOUND WAS. 23:18.798 --> 23:21.701 SO THE MORE ENERGY THAT GOES INTO THE ORIGINAL SOUND, THE 23:21.701 --> 23:24.004 FARTHER IT CAN TRAVEL. 23:24.004 --> 23:27.073 AND SO IF YOU HAVE LIKE A WHISPER YOU MIGHT NOT BE ABLE TO 23:27.073 --> 23:30.443 HEAR THAT MORE THAN A FEW FEET AWAY, BUT IF YOU HAVE A LOUD 23:30.443 --> 23:32.645 VOLCANO EXPLODING WITH A LOT OF ENERGY YOU MIGHT BE ABLE TO HEAR 23:32.645 --> 23:34.447 THAT HUNDREDS OF MILES AWAY. 23:34.447 --> 23:34.814 >> HI. 23:34.814 --> 23:39.819 MY NAME IS CASSIDY, AND I GO TO WEST PARK ELEMENTARY SCHOOL IN 23:39.819 --> 23:40.086 MOSCOW. 23:40.086 --> 23:45.358 THIS IS MY QUESTION -- ARE THERE SOFT SOUNDS YOU CAN'T HEAR? 23:45.358 --> 23:46.760 >> OH, YES. 23:46.760 --> 23:50.930 AGAIN, WE HAVE TO HAVE A CERTAIN AMOUNT OF ENERGY COMING INTO OUR 23:50.930 --> 23:54.834 EARS TO MOVE OUR LITTLE CILIA AROUND ENOUGH FOR US TO DETECT 23:54.834 --> 23:56.836 THE SOUND. 23:56.836 --> 24:02.042 THERE ARE VERY, VERY FAINT SOUNDS WE CAN'T HEAR. 24:02.042 --> 24:05.512 IT'S LIKE INSECTS STRACHG THEMSELVES. 24:05.512 --> 24:08.581 WE'VE BEEN ABLE TO PICK UP THAT SOUND WITH SENSITIVE 24:08.581 --> 24:11.051 MICROPHONES, BUT NO MATTER HOW HARD YOU LISTEN I DON'T THINK 24:11.051 --> 24:13.787 YOU CAN HEAR A BUG SCRATCHING ITS BACK. 24:13.787 --> 24:15.622 >> LET ME ASK A COUPLE OTHER QUESTIONS. 24:15.622 --> 24:18.525 WHY DID YOU GUYS DECIDE TO STUDY PHYSICS AND THEREFORE STUDY 24:18.525 --> 24:20.160 ABOUT SOUND? 24:20.160 --> 24:22.629 >> SO WHEN I WAS IN COLLEGE, I REALLY LIKED MATH. 24:22.629 --> 24:26.066 I WAS GOOD AT MATH, AND I REALLY LIKED SCIENCE, BUT DIDN'T KNOW 24:26.066 --> 24:27.734 WHAT AREA I WANTED TO GO INTO. 24:27.734 --> 24:32.105 SO MY FIRST YEAR OF COLLEGE I STARTED WORKING, I TOOK A 24:32.105 --> 24:34.874 PHYSICS CLASS AND REALIZED THAT THAT WAS THE PERFECT COMBINATION 24:34.874 --> 24:39.879 OF BEING ABLE TO USE MY MATH SKILLS AND THEN SCIENCE, AND I 24:39.879 --> 24:42.716 STARTED WORKING FOR A PROFESSOR WHO DID ASTRONOMY, WHICH WAS THE 24:42.716 --> 24:46.353 COOLEST THING TO ME AT THE TIME. 24:46.353 --> 24:50.090 SO THEN I WAS ABLE TO COMBINE MATH, PHYSICS, AND ASTRONOMY 24:50.090 --> 24:52.826 INTO THE SAME LIFE TRAJECTORY. 24:52.826 --> 24:54.761 SO THAT'S BEEN GREAT. 24:54.761 --> 24:55.395 >> STEVE? 24:55.395 --> 24:59.599 >> WELL, I HAD A VERY GOOD HIGH SCHOOL PHYSICS TEECHER, AND HE 24:59.599 --> 25:04.404 INSPIRED ME, AND HE STRONGLY INFLUENCED MY CHOICE OF CAREER 25:04.404 --> 25:09.309 AND STUDY, BUT PHYSICS AND SCIENCE IN GENERAL, I LIKE THE 25:09.309 --> 25:13.480 IDEA OF BEING ABLE TO FIGURE OUT HOW THINGS WORK. 25:13.480 --> 25:14.881 HOW THE UNIVERSE WORKS. 25:14.881 --> 25:22.255 WE LIVE IN A WONDEROUS PLACE, AND LEARNING MORE ABOUT IT IS 25:22.255 --> 25:23.490 JUST FASCINATING. 25:23.490 --> 25:27.627 AND SCIENCE SEEMED TO ME AND STILL DOES THE BEST WAY TO GO 25:27.627 --> 25:30.263 ABOUT LEARNING MORE ABOUT THE WORLD AROUND US. 25:30.263 --> 25:34.000 >> STEVE, IF A STUDENT WANTS TO BECOME A PHYSICIST AND STUDY 25:34.000 --> 25:37.337 SOUND, WHAT SHOULD THEY DO WHEN THEY GET TO SCHOOL, WHAT CLASSES 25:37.337 --> 25:40.073 SHOULD THEY TAKE? 25:40.073 --> 25:41.274 >> OH, SCIENCE. 25:41.274 --> 25:43.076 SCIENCE AND MATHEMATICS. 25:43.076 --> 25:46.346 MATHEMATICS IS THE LANGUAGE OF WHICH SCIENCE IS SPOKEN. 25:46.346 --> 25:50.550 SO YOU NEED TO BE FAIRLY FLUENT WITH MATH IN ORDER TO DO 25:50.550 --> 25:50.817 SCIENCE. 25:50.817 --> 25:57.457 BUT I WOULD SAY SAMPLE AS MANY SCIENCE CLASSES AS YOU CAN, AND 25:57.457 --> 25:59.392 GO WITH WHAT YOU FIND INTERESTING. 25:59.392 --> 26:01.961 WHAT FASCINATES YOU. 26:01.961 --> 26:03.563 >> WOULD I AGREE WITH THAT TOO. 26:03.563 --> 26:06.466 THE MATHEMATICS IS IMPORTANT BECAUSE IT HELPS YOU KIND OF, 26:06.466 --> 26:08.768 AGAIN, SPEAK THE LANGUAGE OF THE SCIENCES. 26:08.768 --> 26:12.972 WHEN I STARTED TAKING SCIENCE I TOOK BIOLOGY AND CHEMISTRY, AND 26:12.972 --> 26:16.609 GEOLOGY, PHYSICS, AND THEY'RE ALL -- THEY ALL GET USED 26:16.609 --> 26:19.579 TOGETHER, THERE'S NOT CLEARLY SEPARATED OUT FIELDS IN 26:19.579 --> 26:22.982 ASTRONOMY, THERE'S A LOT OF CHEMISTRY AND IN PHYSICS THERE'S 26:22.982 --> 26:23.249 BIOLOGY. 26:23.249 --> 26:26.252 SO I WOULD HAVE TO AGREE WITH STEVE, TAKE AS MUCH SCIENCE AS 26:26.252 --> 26:28.688 YOU CAN SO YOU CAN FIND THE THING YOU'RE REAL LIQUEURUS 26:28.688 --> 26:30.890 ABOUT AND WANT TO KEEP ASKING QUESTIONS ABOUT. 26:30.890 --> 26:34.594 >> I'M SORRY WE'VE RUN OUT OF TIME. 26:34.594 --> 26:36.730 I THANK STEVE SHROPSHIRE AND KATHRYN DEVINE FOR ANSWERING OUR 26:36.730 --> 26:37.263 QUESTIONS. 26:37.263 --> 26:37.797 THANKS, STEVE. 26:37.797 --> 26:39.632 >> THANK YOU. 26:39.632 --> 26:40.367 >> THANKS, KATHRYN. 26:40.367 --> 26:41.868 >> THANKS SO MUCH FOR HAVING US. 26:41.868 --> 26:45.705 >> YOU CAN LEARN LOTS MORE ABOUT SOUNDS AND OTHER TOPICS ON THE 26:45.705 --> 26:48.108 "D4K" WEBSITE AND WE'LL ANSWER MORE QUESTIONS ABOUT SOUND IN 26:48.108 --> 26:49.175 THE "D4K" WEB ONLY. 26:49.175 --> 26:53.646 YOU'LL FIND IT ALL AT IDAHOPTV.ORG/D4K. 26:53.646 --> 26:56.916 OUR LATEST WINNER IN OUR QUESTION CONTEST IS TAYLOR AT 26:56.916 --> 26:59.452 MRS. 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