1 00:00:04,701 --> 00:00:10,634 [dramatic percussion music] 2 00:00:18,734 --> 00:00:20,834 - HEY, THERE. WELCOME TO "NASA LAUNCHPAD." 3 00:00:20,834 --> 00:00:22,734 I'M YOUR HOST, VINCE WHITFIELD. 4 00:00:22,734 --> 00:00:24,467 CHECK THIS OUT. 5 00:00:29,300 --> 00:00:32,167 TODAY WE'RE GOING TO BE TALKING ABOUT HOW THIS WORKS 6 00:00:32,167 --> 00:00:34,434 AND SOME OTHER COOL STUFF BERNOULLI DID. 7 00:00:34,434 --> 00:00:36,267 OH, THAT'S DANIEL BERNOULLI, 8 00:00:36,267 --> 00:00:38,734 THE DUTCH-SWISS MATHEMATICIAN KNOWN FOR-- 9 00:00:38,734 --> 00:00:40,767 THAT'S RIGHT-- THE BERNOULLI PRINCIPLE. 10 00:00:40,767 --> 00:00:42,434 REMEMBER BERNOULLI'S PRINCIPLE? 11 00:00:42,434 --> 00:00:44,267 IF YOU DON'T, THAT'S OKAY. 12 00:00:44,267 --> 00:00:47,434 LET'S CHECK IN WITH JAXA ASTRONAUT KOICHI WAKATA 13 00:00:47,434 --> 00:00:49,300 AND ESA ASTRONAUT FRANK DEWINNE 14 00:00:49,300 --> 00:00:51,434 ON BOARD THE INTERNATIONAL SPACE STATION 15 00:00:51,434 --> 00:00:52,968 TO REVIEW THIS PRINCIPLE WITH US. 16 00:00:52,968 --> 00:00:54,567 AND LET US SEE HOW BERNOULLI'S PRINCIPLE 17 00:00:54,567 --> 00:00:57,067 CAN BE DEMONSTRATED FROM SPACE. 18 00:00:57,067 --> 00:00:59,400 - IN A FLUID FLOW, 19 00:00:59,400 --> 00:01:02,367 WHEN THE FLOW GETS HIGHER, 20 00:01:02,367 --> 00:01:05,767 THE PRESSURE DECREASES. 21 00:01:05,767 --> 00:01:12,067 AND THIS FACT IS NOW WELL-KNOWN AS THE BERNOULLI'S PRINCIPLE. 22 00:01:12,067 --> 00:01:15,901 IF YOU APPLY THIS PRINCIPLE IN THE FLUID FLOW 23 00:01:15,901 --> 00:01:21,467 IN A CLOSED SYSTEM SUCH AS WATER FLOW IN A TUBE, 24 00:01:21,467 --> 00:01:27,367 IF YOU IMAGINE THE TUBE GETS BIGGER AND NARROWER, 25 00:01:27,367 --> 00:01:31,300 THE PRESSURE ACTUALLY DECREASES 26 00:01:31,300 --> 00:01:34,033 WHEN THE SPEED GETS HIGHER. 27 00:01:34,033 --> 00:01:37,701 AND WHEN THE SPEED OF THE WATER GETS SLOWER, 28 00:01:37,701 --> 00:01:41,767 THE PRESSURE ACTUALLY INCREASES. 29 00:01:41,767 --> 00:01:45,133 ONE OF THE EXAMPLES THAT I CAN GIVE YOU IS THAT-- 30 00:01:45,133 --> 00:01:49,000 THINK ABOUT THE GARDEN HOSE. 31 00:01:49,000 --> 00:01:52,234 AND IF WATER IS COMING OUT FROM THE GARDEN HOSE 32 00:01:52,234 --> 00:01:54,834 WITH A MAXIMUM SPEED, 33 00:01:54,834 --> 00:01:57,767 IF YOU STILL WANT TO INCREASE THE SPEED OF THE WATER 34 00:01:57,767 --> 00:01:59,767 COMING OUT OF THE GARDEN HOSE, 35 00:01:59,767 --> 00:02:01,234 WHAT YOU'RE GOING TO DO IS, 36 00:02:01,234 --> 00:02:06,634 YOU'RE GOING TO PUT YOUR THUMB ONTO THE EXIT OF THE HOSE. 37 00:02:06,634 --> 00:02:10,534 BY DOING THAT, THE SPEED OF THE WATER INCREASES, 38 00:02:10,534 --> 00:02:12,067 AND AT THE SAME TIME, 39 00:02:12,067 --> 00:02:15,033 THE PRESSURE OF THE WATER DECREASES. 40 00:02:15,033 --> 00:02:18,200 - YOU HEARD KOICHI WAKATA TALK ABOUT WATER IN A GARDEN HOSE. 41 00:02:18,200 --> 00:02:20,901 AND, YES, BERNOULLI'S PRINCIPLE DEALS WITH FLUID, 42 00:02:20,901 --> 00:02:23,000 BUT HERE'S AN IMPORTANT THING TO KEEP IN MIND: 43 00:02:23,000 --> 00:02:25,601 FLUID DOESN'T NECESSARILY MEAN LIQUID. 44 00:02:25,601 --> 00:02:27,901 FLUID IS A GENERIC NAME THAT APPLIES TO SUBSTANCES 45 00:02:27,901 --> 00:02:29,801 THAT BEHAVE IN CERTAIN WAYS. 46 00:02:29,801 --> 00:02:32,200 FLUIDS FLOW SMOOTHLY AND AROUND THINGS. 47 00:02:32,200 --> 00:02:34,834 SO GASES CAN BE FLUIDS, AS CAN PLASMA 48 00:02:34,834 --> 00:02:37,467 AND EVEN, TO SOME EXTENT, PLASTIC SOLIDS. 49 00:02:37,467 --> 00:02:39,167 LET'S TAKE A LOOK AT ANOTHER DEMONSTRATION 50 00:02:39,167 --> 00:02:40,701 OF BERNOULLI'S PRINCIPLE, 51 00:02:40,701 --> 00:02:44,100 THIS TIME SHOWING HOW IT CAN APPLY TO A GAS, LIKE AIR. 52 00:02:44,100 --> 00:02:45,801 - WE ARE PLACING THESE CONTAINERS 53 00:02:45,801 --> 00:02:50,200 NOT SO FAR FROM EACH OTHER, ABOUT FIVE TO TEN CENTIMETERS. 54 00:02:50,200 --> 00:02:52,267 AND THEN KOICHI IS GOING TO BLOW 55 00:02:52,267 --> 00:02:54,934 IN THE MIDDLE OF THOSE TWO CONTAINERS. 56 00:02:54,934 --> 00:02:57,067 WHAT DO YOU EXPECT THAT WILL HAPPEN? 57 00:02:57,067 --> 00:02:58,634 BECAUSE HE BLOWS IN THE MIDDLE, 58 00:02:58,634 --> 00:03:02,067 THE CONTAINERS ARE GOING TO MOVE AWAY FROM EACH OTHER, 59 00:03:02,067 --> 00:03:04,167 OR IF HE IS BLOWING IN THE MIDDLE, 60 00:03:04,167 --> 00:03:06,601 THE CONTAINERS ARE GOING TO COME TOGETHER? 61 00:03:06,601 --> 00:03:09,067 LET'S HAVE A LOOK. 62 00:03:16,300 --> 00:03:18,400 WHAT YOU CAN VERY EASILY SEE HERE 63 00:03:18,400 --> 00:03:20,767 IS, THE CONTAINERS ARE DRIFTING TOGETHER. 64 00:03:20,767 --> 00:03:22,267 WHAT IS HAPPENING, 65 00:03:22,267 --> 00:03:25,100 AGAIN, THE AIR THAT KOICHI IS BLOWING 66 00:03:25,100 --> 00:03:26,801 THROUGH THE CONTAINERS 67 00:03:26,801 --> 00:03:30,067 HAS HIGHER VELOCITY THAN THE SURROUNDING AIR. 68 00:03:30,067 --> 00:03:31,267 BECAUSE OF THAT, 69 00:03:31,267 --> 00:03:34,000 THE AIR TRAVELING IN BETWEEN THE CONTAINERS 70 00:03:34,000 --> 00:03:35,267 HAS A LOWER PRESSURE 71 00:03:35,267 --> 00:03:37,701 BECAUSE IT'S MOVING AT A HIGHER SPEED. 72 00:03:37,701 --> 00:03:40,234 BECAUSE OF THAT, THE PRESSURE ON THE OUTSIDE 73 00:03:40,234 --> 00:03:42,868 IS PRESSING THE TWO CONTAINERS TOGETHER. 74 00:03:42,868 --> 00:03:45,801 YOU CAN ALSO OBSERVE THIS WHEN YOU'RE DRIVING ON A HIGHWAY 75 00:03:45,801 --> 00:03:48,300 AND YOU GET TOO CLOSE TO A TRUCK, FOR EXAMPLE, 76 00:03:48,300 --> 00:03:50,000 THAT IS DRIVING NEXT TO YOU. 77 00:03:50,000 --> 00:03:53,033 AUTOMATICALLY YOU WILL BE DRAGGED TOWARDS THAT TRUCK, 78 00:03:53,033 --> 00:03:55,434 AND YOU NEED TO STEER AWAY FROM THE TRUCK. 79 00:03:55,434 --> 00:03:58,634 SO THIS IS ONE OF THE EXAMPLES AS WELL 80 00:03:58,634 --> 00:04:00,767 OF THE BERNOULLI PRINCIPLE. 81 00:04:00,767 --> 00:04:02,000 - GUESS WHAT. 82 00:04:02,000 --> 00:04:03,300 YOU DON'T HAVE TO BE ON THE ISS 83 00:04:03,300 --> 00:04:04,667 TO TRY THIS DEMONSTRATION. 84 00:04:04,667 --> 00:04:06,934 OH, SURE, YOUR FOOD CONTAINERS WON'T STAY SUSPENDED 85 00:04:06,934 --> 00:04:09,868 IN MIDAIR ON EARTH LIKE THEY DID ON THE ISS. 86 00:04:09,868 --> 00:04:11,701 BUT TRY THIS DEMONSTRATION WITH TWO BALLOONS 87 00:04:11,701 --> 00:04:13,067 HANGING CLOSE TO EACH OTHER. 88 00:04:13,067 --> 00:04:16,467 THESE BALLOONS ARE HANGING FROM STRING TAPED TO A DOORWAY. 89 00:04:16,467 --> 00:04:18,367 WHAT DO YOU THINK WILL HAPPEN WHEN YOU BLOW GENTLY 90 00:04:18,367 --> 00:04:20,067 BETWEEN THE BALLOONS? 91 00:04:20,067 --> 00:04:22,534 THAT'S RIGHT. THEY ARE PULLED TOGETHER. 92 00:04:22,534 --> 00:04:24,868 THE AIR MOVING AIR BETWEEN THEM HAS LESS PRESSURE 93 00:04:24,868 --> 00:04:26,868 THAN THE AIR ON THE OTHER SIDE OF EACH BALLOON, 94 00:04:26,868 --> 00:04:28,501 SO THEY'RE PUSHED TOGETHER. 95 00:04:28,501 --> 00:04:31,734 HERE'S ANOTHER EXAMPLE THAT WORKS ON EARTH AND IN SPACE. 96 00:04:31,734 --> 00:04:34,033 WATCH FRANK'S DEMONSTRATION WITH A PIECE OF PAPER, 97 00:04:34,033 --> 00:04:36,000 AND THEN TRY IT YOURSELF. 98 00:04:36,000 --> 00:04:39,767 - RIGHT NOW, WHAT-- FRANK HAS A PIECE OF PAPER. 99 00:04:39,767 --> 00:04:41,968 IT'S CURVED. 100 00:04:41,968 --> 00:04:45,033 AND WHAT HE'S GOING TO DO IS, 101 00:04:45,033 --> 00:04:49,868 NOW HE'S GOING TO HOLD THIS PAPER, AND IT'S CURVED, 102 00:04:49,868 --> 00:04:54,300 AND HE'S GOING TO BLOW ON THE TOP SURFACE OF THE PAPER. 103 00:04:54,300 --> 00:04:56,567 WHAT DO YOU THINK THIS PAPER WILL DO? 104 00:04:56,567 --> 00:05:00,634 SINCE THE PAPER IS CURVED LIKE THIS, 105 00:05:00,634 --> 00:05:04,567 DO YOU THINK THE PAPER WILL COME DOWN OR COMES UP? 106 00:05:04,567 --> 00:05:07,067 LET'S SEE WHAT HAPPENS. 107 00:05:10,400 --> 00:05:16,167 AS YOU SEE, WHEN FRANK BLOWS AIR ON THE TOP SIDE OF THE PAPER, 108 00:05:16,167 --> 00:05:20,434 THE PAPER ITSELF LIFTS UP. 109 00:05:20,434 --> 00:05:25,434 THIS IS AGAIN ONE EXAMPLE OF BERNOULLI'S PRINCIPLE. 110 00:05:25,434 --> 00:05:29,534 THE AIR THAT GOES ON THE TOP SURFACE OF THE PAPER 111 00:05:29,534 --> 00:05:31,367 HAS A HIGHER VELOCITY 112 00:05:31,367 --> 00:05:35,000 THAN THE AIR THAT IS UNDERNEATH THE PAPER. 113 00:05:35,000 --> 00:05:37,801 BECAUSE OF THE DIFFERENCE IN THE VELOCITY, 114 00:05:37,801 --> 00:05:41,701 THE PRESSURE OF THE UPPER SURFACE HAS A SMALL NUMBER-- 115 00:05:41,701 --> 00:05:45,400 SMALL PRESSURE THAN THE LOWER SURFACE. 116 00:05:45,400 --> 00:05:48,734 AS A RESULT, THE PAPER IS LIFTED UP. 117 00:05:48,734 --> 00:05:50,701 - THIS IS A PRINCIPLE, OF COURSE, 118 00:05:50,701 --> 00:05:53,634 THAT I HAVE USED A LOT IN MY PREVIOUS CAREER, 119 00:05:53,634 --> 00:05:55,667 BECAUSE I USED TO BE A PILOT. 120 00:05:55,667 --> 00:05:57,901 AND THIS IS HOW AIRPLANES FLY. 121 00:05:57,901 --> 00:06:00,334 IF YOU LOOK TO THE WING OF AN AIRPLANE, 122 00:06:00,334 --> 00:06:01,767 YOU SEE THAT IT'S CURVED, 123 00:06:01,767 --> 00:06:03,868 ALWAYS A LITTLE BIT TOWARDS THE BOTTOM. 124 00:06:03,868 --> 00:06:06,200 THE SIDE ON THE TOP SIDE IS LONGER 125 00:06:06,200 --> 00:06:08,667 AND IS MORE CURVED THAN THE BOTTOM SIDE. 126 00:06:08,667 --> 00:06:10,567 THIS MEANS THAT THE AIR TRAVELING 127 00:06:10,567 --> 00:06:12,033 ON THE TOP OF THE WING 128 00:06:12,033 --> 00:06:14,868 WILL TRAVEL FASTER THAN THE AIR UNDERNEATH THE WING, 129 00:06:14,868 --> 00:06:16,567 CREATING A LOWER PRESSURE 130 00:06:16,567 --> 00:06:18,501 AND LIFTING THE WING UP. 131 00:06:18,501 --> 00:06:20,701 THIS IS WHAT WE CALL "LIFT," 132 00:06:20,701 --> 00:06:23,234 AND BECAUSE OF THIS LIFT, WE CAN TRAVEL 133 00:06:23,234 --> 00:06:25,634 AND WE CAN FLY ALL AROUND THE WORLD. 134 00:06:25,634 --> 00:06:28,868 NOT ONLY ME, BUT YOU AS WELL CAN TRAVEL WHEREVER YOU WANT 135 00:06:28,868 --> 00:06:30,834 THANKS TO THE BERNOULLI EFFECT. 136 00:06:30,834 --> 00:06:32,167 - SO THERE YOU GO. 137 00:06:32,167 --> 00:06:34,133 WHEN YOU INCREASE THE SPEED IN A STREAM OF FLUID-- 138 00:06:34,133 --> 00:06:36,267 REMEMBER THAT'S BOTH LIQUIDS AND GASES-- 139 00:06:36,267 --> 00:06:38,501 THE PRESSURE OF THAT STREAM DECREASES. 140 00:06:38,501 --> 00:06:40,000 PRETTY COOL, HUH? 141 00:06:40,000 --> 00:06:41,901 BERNOULLI'S PRINCIPLE RELATES TO EVERYTHING, 142 00:06:41,901 --> 00:06:43,734 FROM SPRAYING YOUR BEST FRIEND WITH THE HOSE 143 00:06:43,734 --> 00:06:45,267 TO FLYING IN AN AIRPLANE. 144 00:06:45,267 --> 00:06:47,634 THERE'S ACTUALLY MORE THAN BERNOULLI'S PRINCIPLE INVOLVED 145 00:06:47,634 --> 00:06:49,300 WHEN YOU TAKE OFF IN AN AIRPLANE. 146 00:06:49,300 --> 00:06:51,501 BUT THAT'S ANOTHER TOPIC FOR ANOTHER "NASA LAUNCHPAD." 147 00:06:51,501 --> 00:06:53,300 WELL, THAT'S IT FOR NOW. 148 00:06:53,300 --> 00:06:55,534 SPECIAL THANKS TO OUR ON-ORBIT ASTRONAUTS. 149 00:06:55,534 --> 00:06:57,567 UNTIL NEXT TIME, I'M VINCE WHITFIELD. 150 00:06:57,567 --> 00:06:59,467 THANKS FOR WATCHING "NASA LAUNCHPAD."