1 00:00:00,000 --> 00:00:18,080 Hi, welcome to NASA Connect, the show that connects you to the world of math, science, 2 00:00:18,080 --> 00:00:20,680 technology and NASA. 3 00:00:20,680 --> 00:00:25,520 I'm Jennifer Pulley and this is Van Hughes. 4 00:00:25,520 --> 00:00:27,760 Jennifer, what is up with the blindfold? 5 00:00:27,760 --> 00:00:29,600 Just one second. 6 00:00:29,600 --> 00:00:33,960 We always start each NASA Connect episode with a celebrity who introduces the show and 7 00:00:33,960 --> 00:00:36,200 today I thought I'd surprise Van. 8 00:00:36,200 --> 00:00:37,200 Is it Norbert? 9 00:00:37,200 --> 00:00:40,120 No, Van, it's definitely not Norbert. 10 00:00:40,120 --> 00:00:44,280 However, every time Norbert appears with questions, have your cue cards from the lesson guide 11 00:00:44,280 --> 00:00:46,320 ready to answer the questions he gives you. 12 00:00:46,320 --> 00:00:50,840 And teachers, every time Norbert appears with a remote, that's your cue to pause the videotape 13 00:00:50,840 --> 00:00:53,040 and discuss the cue card questions. 14 00:00:53,040 --> 00:00:57,760 And teachers, don't forget, the lesson guide can be downloaded from our NASA Connect website. 15 00:00:57,920 --> 00:01:01,840 Okay, now that you have all that important information out of the way, what about my 16 00:01:01,840 --> 00:01:02,840 surprise? 17 00:01:02,840 --> 00:01:03,840 Okay, follow me. 18 00:01:03,840 --> 00:01:04,840 Jen? 19 00:01:04,840 --> 00:01:05,840 Jen? 20 00:01:05,840 --> 00:01:06,840 Just kidding, just kidding. 21 00:01:06,840 --> 00:01:07,840 Come on. 22 00:01:07,840 --> 00:01:08,840 Are you ready? 23 00:01:08,840 --> 00:01:09,840 Stand right there. 24 00:01:09,840 --> 00:01:10,840 Okay. 25 00:01:10,840 --> 00:01:11,840 Hang tight, one second. 26 00:01:11,840 --> 00:01:12,840 No way! 27 00:01:12,840 --> 00:01:13,840 Jackie Chan, you're here! 28 00:01:13,840 --> 00:01:14,840 I'm here! 29 00:01:14,840 --> 00:01:15,840 I'm here! 30 00:01:15,840 --> 00:01:16,840 I'm here! 31 00:01:16,840 --> 00:01:17,840 I'm here! 32 00:01:17,840 --> 00:01:18,840 I'm here! 33 00:01:18,840 --> 00:01:19,840 I'm here! 34 00:01:19,840 --> 00:01:20,840 I'm here! 35 00:01:20,840 --> 00:01:21,840 I'm here! 36 00:01:21,840 --> 00:01:22,840 I'm here! 37 00:01:22,840 --> 00:01:23,840 I'm here! 38 00:01:23,840 --> 00:01:24,840 I'm here! 39 00:01:24,840 --> 00:01:25,840 I'm here! 40 00:01:25,840 --> 00:01:26,840 I'm here! 41 00:01:26,920 --> 00:01:29,800 Jackie Chan, you are a celebrity? 42 00:01:29,800 --> 00:01:30,800 I've seen all your movies. 43 00:01:30,800 --> 00:01:34,160 I've seen Shanghai Noon, Rush Hour, Rumble in the Bronx. 44 00:01:34,160 --> 00:01:37,320 I can't believe you're here at NASA Langley Research Center in Hampton, Virginia. 45 00:01:37,320 --> 00:01:38,320 Van, hang on. 46 00:01:38,320 --> 00:01:40,320 We need to really let Jackie introduce the show. 47 00:01:40,320 --> 00:01:41,320 Oh, okay. 48 00:01:41,320 --> 00:01:42,320 Sorry. 49 00:01:42,320 --> 00:01:43,320 It's okay, Van. 50 00:01:43,320 --> 00:01:49,080 You know, during my visit here at NASA Langley, I've learned that this center is one of the 51 00:01:49,080 --> 00:01:52,520 largest collections of wind tunnels in the world. 52 00:01:52,520 --> 00:01:56,000 In fact, I filmed a movie in a wind tunnel once. 53 00:01:59,000 --> 00:02:01,440 Wow, the wind is so strong. 54 00:02:01,440 --> 00:02:07,640 On today's NASA Connect, you learn how NASA engineers and researchers use geometry and 55 00:02:07,640 --> 00:02:10,360 algebra every day in their work. 56 00:02:10,360 --> 00:02:14,280 You test shapes for drafts just like NASA researchers. 57 00:02:14,280 --> 00:02:21,600 You get connected to a really cool web activity and take a sneak peek at a new airplane. 58 00:02:21,680 --> 00:02:24,000 Is it a bird or a plane? 59 00:02:24,000 --> 00:02:28,120 So get ready, get set, and glow with the flow. 60 00:02:28,120 --> 00:02:30,440 Here on NASA Connect. 61 00:02:30,440 --> 00:02:52,400 Okay, here's the deal. 62 00:02:52,560 --> 00:02:56,560 Van and I are going to conduct a little experiment about drag using go-karts. 63 00:02:56,560 --> 00:03:04,560 Van and I are riding in the same kind of go-kart with the same amount of fuel. 64 00:03:04,560 --> 00:03:05,560 These are constants. 65 00:03:05,560 --> 00:03:09,560 However, Van is taller and heavier than I am. 66 00:03:09,560 --> 00:03:13,560 These two variables, height and weight, might affect the race. 67 00:03:13,560 --> 00:03:15,560 And hopefully, I'll cross the finish line first. 68 00:03:15,560 --> 00:03:17,560 I am the superior driver. 69 00:03:17,720 --> 00:03:24,720 I can't change my weight, but if I change the variable of being taller and crouch down 70 00:03:24,720 --> 00:03:28,720 and become more streamlined, I might have a chance. 71 00:03:40,720 --> 00:03:41,720 Ha! 72 00:03:41,720 --> 00:03:42,720 No way! 73 00:03:42,720 --> 00:03:44,720 How did you win? 74 00:03:44,720 --> 00:03:46,720 Let me explain, Jennifer. 75 00:03:46,880 --> 00:03:50,880 I changed my shape, which allowed the air to flow more smoothly around me. 76 00:03:50,880 --> 00:03:54,880 Your shape interrupted the airflow and caused drag. 77 00:03:54,880 --> 00:03:57,880 This slowed you down and allowed me to win. 78 00:04:01,880 --> 00:04:03,880 So what is drag? 79 00:04:03,880 --> 00:04:06,880 Drag is the force that opposes or resists motion. 80 00:04:06,880 --> 00:04:09,880 The interruption or resistance to airflow causes drag. 81 00:04:09,880 --> 00:04:14,880 You've probably experienced drag when you've ever stuck your hand out the window of a moving car. 82 00:04:15,040 --> 00:04:21,040 When you extend your arm like this, with your palm forward, the force of drag pushes your hand back. 83 00:04:21,040 --> 00:04:26,040 But when you tilt your hand like this, it creates lift and lifts your hand upward. 84 00:04:26,040 --> 00:04:31,040 Lift and drag are a few of the aerodynamic forces that act on an airplane when it flies. 85 00:04:31,040 --> 00:04:33,040 How do airplanes fly? 86 00:04:33,040 --> 00:04:39,040 Well, to understand flight, you must first understand air. 87 00:04:39,200 --> 00:04:45,200 We are surrounded by air all the time, but we can't feel it 88 00:04:45,200 --> 00:04:50,200 because the air pressure is equal on all sides of our body. 89 00:04:50,200 --> 00:04:55,200 But what if we change the air pressure on one side of an object? 90 00:04:55,200 --> 00:04:58,200 Check out this cool experiment. 91 00:05:00,200 --> 00:05:04,200 Hey, why did the paper lift up when I blew across the top? 92 00:05:04,200 --> 00:05:08,200 Well, when the paper is resting against my chin like this, 93 00:05:08,360 --> 00:05:12,360 the air pressure on top is equal to the air pressure on the bottom. 94 00:05:12,360 --> 00:05:16,360 But when I blow, I change the air pressure on the top. 95 00:05:16,360 --> 00:05:20,360 The shape of the paper in its original position is kind of like an airplane's wing. 96 00:05:20,360 --> 00:05:22,360 It is curved on the top. 97 00:05:22,360 --> 00:05:28,360 Because of this shape, air molecules move faster across the wing's top than across its bottom. 98 00:05:28,360 --> 00:05:34,360 Swiss mathematician Daniel Bernoulli discovered that faster-moving fluids, such as air, 99 00:05:34,360 --> 00:05:37,360 exert less pressure than slower-moving fluids. 100 00:05:37,520 --> 00:05:43,520 Because of its shape, the air over the top of the wing moves more quickly and exerts less pressure. 101 00:05:43,520 --> 00:05:47,520 When the pressure on top of the wing is less than the pressure under the wing, 102 00:05:47,520 --> 00:05:50,520 lift is produced and the airplane flies. 103 00:05:50,520 --> 00:05:53,520 What does all this have to do with algebra and geometry? 104 00:05:53,520 --> 00:05:57,520 Everything! Geometry is the study of shape and size. 105 00:05:57,520 --> 00:06:02,520 Geometry was probably first developed to help measure the Earth and its objects. 106 00:06:02,680 --> 00:06:07,680 Knowledge of geometry helps you better understand things like engineering and science. 107 00:06:07,680 --> 00:06:11,680 Algebra is a mathematical tool for solving problems. 108 00:06:11,680 --> 00:06:14,680 Learning algebra is a bit like learning to read and write. 109 00:06:14,680 --> 00:06:19,680 Knowledge of algebra can give you more power to solve problems and accomplish what you want in life. 110 00:06:19,680 --> 00:06:26,680 At NASA, engineers use algebra and geometry when they measure and design models to be tested in wind tunnels. 111 00:06:26,680 --> 00:06:31,680 Like today's NASA engineers, Orville and Wilbur Wright used algebra and geometry. 112 00:06:31,840 --> 00:06:34,840 By blowing a certain amount of air over models in a wind tunnel, 113 00:06:34,840 --> 00:06:40,840 the Wright brothers tested and compared different wing shapes, rudder shapes, and propeller shapes. 114 00:06:40,840 --> 00:06:45,840 Hey, let's conduct an experiment very similar to the Wright brothers and test different shapes for drag. 115 00:06:45,840 --> 00:06:49,840 Good idea, Van, but first, teachers, make sure you check out the NASA Connect website 116 00:06:49,840 --> 00:06:52,840 and download the lesson guide for today's program. 117 00:06:52,840 --> 00:06:57,840 In it, you'll find step-by-step instructions and analysis questions for today's classroom activity. Van? 118 00:06:58,000 --> 00:07:03,000 In honor of the Wright brothers, NASA Connect traveled south to Kill Devil Hills, North Carolina 119 00:07:03,000 --> 00:07:05,000 to conduct today's classroom activity. 120 00:07:05,000 --> 00:07:11,000 Hi, we're from First White Middle School in Kill Devil Hills, North Carolina. 121 00:07:11,000 --> 00:07:16,000 NASA Connect asked us to show you how to do this show's classroom activity. 122 00:07:16,000 --> 00:07:17,000 It's called... 123 00:07:17,000 --> 00:07:20,000 What a Drag! 124 00:07:20,000 --> 00:07:22,000 This activity has three parts. 125 00:07:22,000 --> 00:07:25,000 In part one, you'll learn how shape affects drag. 126 00:07:25,160 --> 00:07:29,160 In part two, you'll learn how surface area affects drag. 127 00:07:29,160 --> 00:07:33,160 And in part three, you'll apply what you've learned from parts one and two 128 00:07:33,160 --> 00:07:36,160 to determine the object with the least amount of drag. 129 00:07:36,160 --> 00:07:40,160 Make sure your teacher has a lesson guide for this program. 130 00:07:40,160 --> 00:07:43,160 All the steps and materials are in it. 131 00:07:43,160 --> 00:07:47,160 Before starting the experiment, construct your drag apparatus. 132 00:07:47,160 --> 00:07:49,160 Then discuss these questions. 133 00:07:49,160 --> 00:07:51,160 What is drag? 134 00:07:51,160 --> 00:07:53,160 How would shape affect drag? 135 00:07:53,320 --> 00:07:58,320 What are some direct and indirect negative effects of drag on a vehicle? 136 00:07:58,320 --> 00:08:01,320 Now, let's test these four shapes for drag. 137 00:08:01,320 --> 00:08:06,320 First, verify that each of the shapes has the same amount of frontal surface area 138 00:08:06,320 --> 00:08:09,320 and record your information in the data sheet. 139 00:08:09,320 --> 00:08:13,320 Next, place two shapes on the drag apparatus like this. 140 00:08:13,320 --> 00:08:15,320 Turn the fan on low. 141 00:08:15,320 --> 00:08:18,320 Which shape moves closer to the fan? 142 00:08:18,320 --> 00:08:20,320 That's the one with the least amount of drag. 143 00:08:20,480 --> 00:08:25,480 Record your observations and repeat these steps using different combinations of the shapes. 144 00:08:25,480 --> 00:08:27,480 Look at your data. 145 00:08:27,480 --> 00:08:30,480 Which shape had the least amount of drag? 146 00:08:30,480 --> 00:08:33,480 Does shape affect drag? 147 00:08:33,480 --> 00:08:36,480 Why or why not? 148 00:08:36,480 --> 00:08:41,480 What other variables could have affected the outcome of the experiment? 149 00:08:42,480 --> 00:08:44,480 Thanks, Debbie. Nice job, guys. 150 00:08:44,480 --> 00:08:47,480 Take five, because we'll be back a little later to continue this activity. 151 00:08:47,640 --> 00:08:53,640 But first, let's head to NASA Langley to see how engineers there are using algebra to solve problems with drag. 152 00:08:53,640 --> 00:08:57,640 They use a wind tunnel instead of a box fan to test models with different shapes. 153 00:08:59,640 --> 00:09:02,640 Why are patterns important in determining drag? 154 00:09:02,640 --> 00:09:06,640 What algebraic relationship shows that a car has drag? 155 00:09:06,640 --> 00:09:10,640 Explain the relationship between pressure and glow. 156 00:09:11,640 --> 00:09:14,640 This is one of NASA Langley's many wind tunnels. 157 00:09:14,800 --> 00:09:17,800 It's called the Basic Aerodynamics Research Tunnel, or BART for short. 158 00:09:17,800 --> 00:09:23,800 Engineers like me use the BART and a technique called flow visualization to try to understand how the air flows around aircraft. 159 00:09:23,800 --> 00:09:30,800 By looking at or visualizing the airflow, we can help aircraft designers create new shapes that are more aerodynamic and produce less drag. 160 00:09:30,800 --> 00:09:35,800 Drag slows down a vehicle or an object, as you observed in the activity you just conducted. 161 00:09:35,960 --> 00:09:40,960 Recently, NASA Langley used its experience in testing and simulating aircraft 162 00:09:40,960 --> 00:09:45,960 to help a car manufacturer visualize and describe the airflow over one of its automobiles. 163 00:09:46,960 --> 00:09:51,960 What we as engineers would really like to see is the air flowing continuously from the front of the car to the back of the car, 164 00:09:51,960 --> 00:09:53,960 like the flow over this cylinder. 165 00:09:53,960 --> 00:09:56,960 There is no interruption in the airflow and there is no drag. 166 00:09:56,960 --> 00:10:01,960 Unfortunately, this is not how things work in real life, so we have to make airplanes and cars streamlined. 167 00:10:02,120 --> 00:10:08,120 This particular automobile is streamlined, which means it was designed to offer minimal resistance to airflow. 168 00:10:08,120 --> 00:10:11,120 Because of its shape, this car has little drag. 169 00:10:11,120 --> 00:10:13,120 You know, that sounds like our activity. 170 00:10:13,120 --> 00:10:16,120 The tetrahedron had the lowest drag because of its shape. 171 00:10:16,120 --> 00:10:20,120 That's right. The shape of airplanes and cars is mainly determined by aerodynamics and safety. 172 00:10:20,120 --> 00:10:23,120 However, a car has additional factors that may affect its shape. 173 00:10:23,120 --> 00:10:27,120 The vehicle must look good for people to buy it, the passengers must be comfortable, 174 00:10:27,120 --> 00:10:31,120 and the vehicle must be able to transport people, cargo, or both. 175 00:10:31,280 --> 00:10:36,280 With this in mind, automotive engineers use geometry to design cars with one of three shapes, 176 00:10:36,280 --> 00:10:39,280 a hatchback, a squareback, or a notchback. 177 00:10:39,280 --> 00:10:42,280 Which of the three shapes do you think would have the highest drag? 178 00:10:43,280 --> 00:10:46,280 Looks like the notchback has the most drag. 179 00:10:46,280 --> 00:10:52,280 You're right. After deciding on the shape to test, we created a scale model of a typical passenger vehicle with a notchback design. 180 00:10:52,280 --> 00:10:56,280 To visualize and measure the airflow around this model, we used the BART, 181 00:10:56,280 --> 00:11:00,280 and materials like kerosene and titanium dioxide, a white powdery substance used in paint. 182 00:11:00,440 --> 00:11:04,440 Visualizing the airflow provides a picture of how the air moves around the vehicle. 183 00:11:04,440 --> 00:11:07,440 Okay, so how do you visualize airflow? 184 00:11:07,440 --> 00:11:10,440 You can't really see air, can you? 185 00:11:10,440 --> 00:11:12,440 No, you can, and that's a good question. 186 00:11:12,440 --> 00:11:15,440 Without special materials, you really can't see air flowing. 187 00:11:15,440 --> 00:11:19,440 So we mixed titanium dioxide and kerosene together and applied it to the surface of the model. 188 00:11:19,440 --> 00:11:25,440 We turned on the wind tunnel, and as air flowed over the model, the kerosene evaporated or turned into a gas. 189 00:11:25,440 --> 00:11:29,440 The titanium dioxide left on the surface shows us an airflow pattern. 190 00:11:29,600 --> 00:11:32,600 This pattern tells us how the air is moving close to the surface. 191 00:11:32,600 --> 00:11:37,600 The measurements we collect allow us to describe the air's properties in motion with numbers. 192 00:11:37,600 --> 00:11:43,600 Luther, that looks really cool, you know, but what does this pattern say about the shape of the car and the drag it produces? 193 00:11:43,600 --> 00:11:49,600 Well, this pattern tells us that the air is actually traveling in the same direction as the car, or in other words, towards the back window. 194 00:11:49,600 --> 00:11:51,600 This is called reverse flow. 195 00:11:51,600 --> 00:11:55,600 Reverse flow creates low pressures on the back of the vehicle, which increases drag. 196 00:11:55,600 --> 00:11:57,600 Remember this drawing? 197 00:11:57,760 --> 00:12:01,760 See how the air flows smoothly over the cylinder and comes together again in the back? 198 00:12:01,760 --> 00:12:10,760 Although this isn't how things work in the real world, the air pressure in the front, P-F, is the same or equal to the pressure in the back, P-B. 199 00:12:10,760 --> 00:12:14,760 When the pressure in the front is equal to the pressure in the back, then there is no drag. 200 00:12:14,760 --> 00:12:16,760 However, look at our notchback model. 201 00:12:16,760 --> 00:12:22,760 See how the air flow separates at the back of the vehicle and the air actually begins to flow in the reverse direction? 202 00:12:22,920 --> 00:12:27,920 This is reverse flow, and the pressure in the front of the model is greater than the pressure in the back. 203 00:12:27,920 --> 00:12:31,920 When the pressure in the front is greater than the pressure in the back, you have drag. 204 00:12:31,920 --> 00:12:39,920 Flow visualization helps us understand how the air flows over the model, but in order to measure the pressures on the surface, we had to use additional techniques. 205 00:12:39,920 --> 00:12:42,920 The most exciting is probably pressure-sensitive paint. 206 00:12:42,920 --> 00:12:51,920 In addition to NASA Langley, NASA Glenn Research Center in Ohio and NASA Ames Research Center in California use pressure-sensitive paint in their wind tunnel tests. 207 00:12:52,080 --> 00:12:58,080 Pressure-sensitive paint, or PSP, is a special paint that glows when exposed to blue light. 208 00:12:58,080 --> 00:13:03,080 The glow is really due to special molecules embedded in the paint called luminophores. 209 00:13:03,080 --> 00:13:07,080 Luminophores. Sounds like a word that comes from illuminate. 210 00:13:07,080 --> 00:13:11,080 That's right. These luminophores are excited or given excess energy by the blue light. 211 00:13:11,080 --> 00:13:18,080 The luminophores don't like to have excess energy, so they get rid of it by either glowing or by bumping into nearby oxygen molecules. 212 00:13:18,240 --> 00:13:25,240 The behavior of the luminophores allows us to see a relationship between the brightness of their glow and the pressure on the surface. 213 00:13:25,240 --> 00:13:28,240 Hmm. A relationship. Sounds like algebra. 214 00:13:28,240 --> 00:13:32,240 That's right. I use algebra in my work every day. Let me show you. 215 00:13:32,240 --> 00:13:38,240 Remember when I said that the behavior of the luminophores allows us to relate the brightness of the glow to the pressure on the surface? 216 00:13:38,240 --> 00:13:40,240 This is done using a graph like this. 217 00:13:40,240 --> 00:13:45,240 The curve on the graph shows an inverse relationship between pressure and glow. 218 00:13:45,400 --> 00:13:48,400 When glow increases, we know the pressure has decreased. 219 00:13:48,400 --> 00:13:51,400 But when glow decreases, we know the pressure has increased. 220 00:13:51,400 --> 00:13:56,400 This inverse relationship can be represented with the following algebraic equation. 221 00:13:56,400 --> 00:14:01,400 Pressure equals quantity glow minus one divided by the slope of the curve. 222 00:14:01,400 --> 00:14:05,400 Using the graph in this algebraic equation, we solve for pressure. 223 00:14:05,400 --> 00:14:09,400 The pressures we calculate can be displayed using different colors like this. 224 00:14:09,400 --> 00:14:14,400 The red regions show where the pressures are high, and the blue regions show where the pressures are low. 225 00:14:14,560 --> 00:14:18,560 As you can see, the pressures in the front of the car are higher than the pressures in the back. 226 00:14:18,560 --> 00:14:22,560 As we calculated earlier, this difference determines the vehicle's drag. 227 00:14:22,560 --> 00:14:27,560 This information is used by car designers to decide if the shape or geometry of a car needs to be changed. 228 00:14:27,560 --> 00:14:33,560 If I were a car designer, I'd change the notchback shape of the car. It creates too much drag. 229 00:14:33,560 --> 00:14:39,560 Well, Van, the research conducted here at the NASA Langley Research Center can be used by automotive engineers and designers 230 00:14:39,560 --> 00:14:43,560 to create new designs and shapes with reduced drag and better fuel efficiency. 231 00:14:43,720 --> 00:14:47,720 This allows drivers like us to save money and protect the environment. 232 00:14:48,720 --> 00:14:51,720 Okay, we've seen how different shapes affect drag. 233 00:14:51,720 --> 00:14:59,720 Now, let's head back to First Flight Middle School and see what would happen if we changed the frontal surface area of an object. 234 00:14:59,720 --> 00:15:01,720 Are you ready, guys? 235 00:15:01,720 --> 00:15:05,720 Ready, Jennifer. Now let's find out how surface area affects drag. 236 00:15:05,720 --> 00:15:08,720 Your teacher will give each group a copy of the disc patterns. 237 00:15:08,720 --> 00:15:12,720 From the lesson guide, select and construct five discs. 238 00:15:12,880 --> 00:15:15,880 Look at one of the discs. What do you think the area is? 239 00:15:15,880 --> 00:15:17,880 Make a prediction and write it down. 240 00:15:17,880 --> 00:15:20,880 Now, calculate the actual area. 241 00:15:20,880 --> 00:15:24,880 What is the difference between your prediction and the actual area? 242 00:15:24,880 --> 00:15:26,880 Are you close? 243 00:15:26,880 --> 00:15:29,880 Repeat these steps for each disc. 244 00:15:29,880 --> 00:15:33,880 Before beginning the experiment, construct the test track. 245 00:15:33,880 --> 00:15:37,880 Choose any disc and place it on the front of the test vehicle like this. 246 00:15:38,040 --> 00:15:41,040 Place the vehicles on the start line. 247 00:15:41,040 --> 00:15:44,040 Make sure the string is nice and tight. 248 00:15:44,040 --> 00:15:49,040 Predict the distance that the test vehicle will travel when the fan is turned on and write it down. 249 00:15:49,040 --> 00:15:53,040 I predict it will travel about 42 centimeters. 250 00:15:53,040 --> 00:15:56,040 I predict it will travel 50 centimeters. 251 00:15:56,040 --> 00:15:59,040 Turn the fan on high for approximately 10 seconds. 252 00:15:59,040 --> 00:16:02,040 This is only a suggested time. 253 00:16:02,040 --> 00:16:06,040 Your time will depend on the fan speed and test vehicles. 254 00:16:06,200 --> 00:16:12,200 Now, measure the distance that the test vehicle moves backward and record it on the data sheet. 255 00:16:12,200 --> 00:16:18,200 Calculate the difference between the predicted distance and the actual distance and record your answer. 256 00:16:18,200 --> 00:16:20,200 How did you do? 257 00:16:20,200 --> 00:16:23,200 Now, test the other discs. 258 00:16:25,200 --> 00:16:32,200 Now that we've gathered our data, let's create a graph that shows the relationship between frontal surface area and distance. 259 00:16:32,360 --> 00:16:36,360 Could I have one member of each group to come up and graph their data? 260 00:16:41,360 --> 00:16:45,360 Great job, guys. Let's look at the graph and answer some questions. 261 00:16:45,360 --> 00:16:48,360 What kind of graph is it? 262 00:16:48,360 --> 00:16:51,360 Do you see a correlation? 263 00:16:51,360 --> 00:16:54,360 If so, what kind is it? 264 00:16:54,360 --> 00:16:58,360 Which surface area produced the least amount of drag? 265 00:16:58,360 --> 00:17:00,360 Now let's put it all together. 266 00:17:00,520 --> 00:17:03,520 Look at the data from the first experiment you did. 267 00:17:03,520 --> 00:17:06,520 Which shape had the least amount of drag? 268 00:17:06,520 --> 00:17:08,520 Tetrahedron. 269 00:17:08,520 --> 00:17:10,520 This shape? 270 00:17:10,520 --> 00:17:14,520 Now look at your data from the second experiment we did on surface area. 271 00:17:14,520 --> 00:17:18,520 What did you find out about the surface area and drag? 272 00:17:18,520 --> 00:17:24,520 Based on your results, which of these four tetrahedrons should have the least amount of drag? 273 00:17:24,520 --> 00:17:27,520 How can we test your predictions? 274 00:17:27,680 --> 00:17:30,680 Let's put the shapes on the drag stand and see what happens. 275 00:17:30,680 --> 00:17:32,680 Great, let's do it. 276 00:17:32,680 --> 00:17:37,680 We'd like to thank the AIAA student mentors from North Carolina State University. 277 00:17:37,680 --> 00:17:39,680 Good job, guys. 278 00:17:39,680 --> 00:17:42,680 Well, thus far, you've seen these students use some of the tools for research. 279 00:17:42,680 --> 00:17:47,680 That being design, construction, testing, and analysis of an experiment. 280 00:17:47,680 --> 00:17:50,680 But you know what? NASA uses some other tools for research. 281 00:17:50,680 --> 00:17:52,680 Computer simulations. 282 00:17:52,840 --> 00:17:54,840 And with a little help from our friend Norbert here, 283 00:17:54,840 --> 00:17:58,840 we're going to transport you to the Fernbank Science Center in Atlanta, Georgia. 284 00:17:58,840 --> 00:18:03,840 Fernbank Science Center is a science resource center for DeKalb County School System. 285 00:18:03,840 --> 00:18:06,840 It has had a relationship with NASA since the early Apollo missions 286 00:18:06,840 --> 00:18:12,840 and recently installed the NASA Aeronautics Education Laboratory to use in its education programs. 287 00:18:12,840 --> 00:18:15,840 Waiting for you at Fernbank are students from McNair Middle School 288 00:18:15,840 --> 00:18:21,840 who will introduce you to the program's featured web simulation, MAX, or Mars Airborne Explorer. 289 00:18:22,000 --> 00:18:25,000 Made especially for NASA Connect by Space.com. 290 00:18:25,000 --> 00:18:28,000 From Norbert's lab, click the activity button. 291 00:18:28,000 --> 00:18:34,000 You'll get to create a Mars exploration aircraft and fly it over a simulated Martian terrain. 292 00:18:34,000 --> 00:18:40,000 You'll be able to see the relationships between thrust, drag, and lift. 293 00:18:40,000 --> 00:18:44,000 Your mission is to pilot the Mars aircraft and release a number of probes 294 00:18:44,000 --> 00:18:46,000 that must land on designated targets. 295 00:18:46,000 --> 00:18:50,000 The right combination and balance will lead to a successful flight. 296 00:18:50,160 --> 00:18:54,160 ePALS Classroom Exchange brings to teachers and students the opportunity 297 00:18:54,160 --> 00:18:59,160 to collaborate with peers, experts, and others using ePALS' free telecommunications 298 00:18:59,160 --> 00:19:01,160 and collaborative tools. 299 00:19:01,160 --> 00:19:05,160 And teachers, be sure to visit Norbert's lab and browse a section called Manager, 300 00:19:05,160 --> 00:19:08,160 a special section to help guide teachers in using activities 301 00:19:08,160 --> 00:19:12,160 that have educational technology interwoven. 302 00:19:12,160 --> 00:19:16,160 A special thanks to another NASA Connect online partner, Space.com. 303 00:19:16,320 --> 00:19:20,320 Devoted to space news, it offers special portals to kids and teachers 304 00:19:20,320 --> 00:19:24,320 at SpaceKids.com and TeachSpace.com. 305 00:19:24,320 --> 00:19:28,320 And a final thanks to our AIAA student mentors from Georgia Tech. 306 00:19:28,320 --> 00:19:32,320 Well, I think that's a wrap from my end, bringing you the power of digital learning. 307 00:19:32,320 --> 00:19:35,320 I'm Shelley Canright for NASA Connect Online. 308 00:19:35,320 --> 00:19:37,320 Okay, let's review. 309 00:19:37,320 --> 00:19:41,320 So far, we've learned how NASA engineers use geometry and algebra, 310 00:19:41,480 --> 00:19:45,480 flow visualization, and glowing paints to help them create more aerodynamic vehicles, 311 00:19:45,480 --> 00:19:49,480 and how shape and surface area affect drag. 312 00:19:49,480 --> 00:19:53,480 We've also learned how computer technology can help you solve problems that are out of this world. 313 00:19:53,480 --> 00:19:57,480 Now, let's learn how NASA engineers are using geometry 314 00:19:57,480 --> 00:20:01,480 to create a concept airplane that looks a lot like a flying wing. 315 00:20:05,480 --> 00:20:10,480 Describe the differences between the blended wing body and today's commercial airplanes. 316 00:20:10,640 --> 00:20:14,640 How do NASA engineers use geometry to estimate frontal surface area? 317 00:20:14,640 --> 00:20:18,640 What design features would increase the drag on a low-speed vehicle? 318 00:20:18,640 --> 00:20:22,640 How could engineers compensate for that drag? 319 00:20:22,640 --> 00:20:26,640 The blended wing body, or BWB as we call it for short, 320 00:20:26,640 --> 00:20:30,640 is an advanced concept passenger airplane. 321 00:20:30,640 --> 00:20:34,640 That means that we're still in the process of deciding and testing what will be the best design. 322 00:20:34,640 --> 00:20:38,640 So far, early studies estimate the blended wing body 323 00:20:38,800 --> 00:20:42,800 to accommodate 1,500 passengers, have a wingspan of 247 feet, 324 00:20:42,800 --> 00:20:46,800 a length of 160 feet, and be more than 40 feet or four stories high. 325 00:20:46,800 --> 00:20:50,800 It kind of resembles a flying wing. 326 00:20:50,800 --> 00:20:54,800 Engineers believe the BWB has potential to perform better than traditional tube-with-wings airplanes, 327 00:20:54,800 --> 00:20:58,800 like the Boeing 747. 328 00:20:58,800 --> 00:21:02,800 Some estimates predict that this new airplane will reduce operating costs 329 00:21:02,800 --> 00:21:06,800 and the amount of fuel the airplane uses. 330 00:21:06,960 --> 00:21:10,960 So, Wendy, what makes the blended wing body so special? 331 00:21:10,960 --> 00:21:14,960 It's shape. 332 00:21:14,960 --> 00:21:18,960 Since we've been discussing shape and geometry in today's program, 333 00:21:18,960 --> 00:21:22,960 let me show you what makes the BWB different from other airplanes today. 334 00:21:22,960 --> 00:21:26,960 If you look down on the top of the plane, you can see that its fuselage, 335 00:21:26,960 --> 00:21:30,960 that's the part that people ride in, and the wing are blended together. 336 00:21:30,960 --> 00:21:34,960 That's how it got its name, the blended wing body. 337 00:21:34,960 --> 00:21:38,960 If we look over the frontal view, we can see that there's a smooth transition 338 00:21:38,960 --> 00:21:42,960 from the fuselage to the wings. 339 00:21:42,960 --> 00:21:46,960 This shape allows more people to sit in the fuselage and even out into the wings. 340 00:21:46,960 --> 00:21:50,960 Remember the picture of the streamlined car Luther showed you? 341 00:21:50,960 --> 00:21:54,960 Just like a car, when an airplane has a smooth shape, it can help reduce drag. 342 00:21:54,960 --> 00:21:58,960 Do you see anything else that makes the BWB different from other airplanes? 343 00:21:58,960 --> 00:22:02,960 Hmm. 344 00:22:02,960 --> 00:22:06,960 Well, like other airplanes. 345 00:22:06,960 --> 00:22:10,960 Right. Just like blending the wing and fuselage together helps to reduce drag, 346 00:22:10,960 --> 00:22:14,960 taking off both the horizontal and vertical tails also helps reduce drag. 347 00:22:14,960 --> 00:22:18,960 Drag, which you learned about earlier, resists thrust. 348 00:22:18,960 --> 00:22:22,960 Thrust, the force that propels the airplane, is usually provided by jet engine. 349 00:22:22,960 --> 00:22:26,960 If an airplane has too much drag, it will need more thrust or engine power. 350 00:22:26,960 --> 00:22:30,960 However, when the airplane is designed for less drag, like the BWB, 351 00:22:30,960 --> 00:22:34,960 less thrust is needed. So, what does this all mean? 352 00:22:34,960 --> 00:22:38,960 Less thrust means less fuel is needed. 353 00:22:38,960 --> 00:22:42,960 And less fuel means less money to buy a ticket. 354 00:22:42,960 --> 00:22:46,960 You got it. Now, Wendy, you said earlier that the BWB is just a concept airplane, 355 00:22:46,960 --> 00:22:50,960 so I guess that means it hasn't been built yet. 356 00:22:50,960 --> 00:22:54,960 Right. It would be too expensive to build the full-size BWB. 357 00:22:54,960 --> 00:22:58,960 NASA and Boeing engineers come together and design some scale models. 358 00:22:58,960 --> 00:23:02,960 Does that mean there's going to be more than one model of the BWB? 359 00:23:02,960 --> 00:23:06,960 Absolutely. If we only built one model, we couldn't collect enough information. 360 00:23:06,960 --> 00:23:10,960 So, we've built a model that's approximately 1% the size of the BWB. 361 00:23:10,960 --> 00:23:14,960 Hey, let's do the math. 362 00:23:14,960 --> 00:23:18,960 What would a 1% model of the BWB look like? 363 00:23:18,960 --> 00:23:22,960 Would it fit in your classroom or in a shoebox? 364 00:23:22,960 --> 00:23:26,960 I know. Let's figure it out. 365 00:23:26,960 --> 00:23:30,960 The BWB will be 247 feet wide, 366 00:23:30,960 --> 00:23:34,960 160 feet long, and 40 feet tall. 367 00:23:34,960 --> 00:23:38,960 Using middle math, let's take 1% of each of those measurements. 368 00:23:38,960 --> 00:23:42,960 Okay. 1% of 247 is 2.47, 369 00:23:42,960 --> 00:23:46,960 or about 2.5 feet wide. 370 00:23:46,960 --> 00:23:50,960 1% of 160 is 1.6, or about 1.5 feet long. 371 00:23:50,960 --> 00:23:54,960 1% of 40 is .4, 372 00:23:54,960 --> 00:23:58,960 or about a half foot tall. 373 00:23:58,960 --> 00:24:02,960 So, yeah. 374 00:24:02,960 --> 00:24:06,960 1% model of the BWB should definitely fit in your classroom. Right, Wendy? 375 00:24:06,960 --> 00:24:10,960 That's right. And here it is. 376 00:24:10,960 --> 00:24:14,960 As I said earlier, building just one scale model like this didn't give us all the information we needed. 377 00:24:14,960 --> 00:24:18,960 So, we built a 2%, 3%, and a 4% model. 378 00:24:18,960 --> 00:24:22,960 They'll all be tested here at NASA Langley in the wind tunnels to determine performance and stability. 379 00:24:22,960 --> 00:24:26,960 Because we can't always predict how the BWB will perform, 380 00:24:26,960 --> 00:24:30,960 it can't tell us how a real pilot will be able to control it in the air. 381 00:24:30,960 --> 00:24:34,960 So, NASA Langley is building another subscale model called the Low-Speed Vehicle, 382 00:24:34,960 --> 00:24:38,960 or LSV, and it will actually fly. 383 00:24:38,960 --> 00:24:42,960 We will take our LSV wind tunnel predictions and compare them to actual flight test data. 384 00:24:42,960 --> 00:24:46,960 The flight test will take place at NASA Dryden Flight Research Center in California. 385 00:24:46,960 --> 00:24:50,960 Engineers want to learn how to control and stabilize this new concept airplane 386 00:24:50,960 --> 00:24:54,960 safely. In a wind tunnel, you just can't simulate that. 387 00:24:54,960 --> 00:24:58,960 The LSV is about 14% the size of a full-size BWB. 388 00:24:58,960 --> 00:25:02,960 14% model of the BWB is about 35 feet wide, 389 00:25:02,960 --> 00:25:06,960 22 feet long, and 6 feet high. 390 00:25:06,960 --> 00:25:10,960 Remember in the classroom activity when you determined that a greater frontal surface area 391 00:25:10,960 --> 00:25:14,960 produced greater drag? Let's look at the frontal view of the 392 00:25:14,960 --> 00:25:18,960 14% BWB model. To estimate the frontal surface area, 393 00:25:18,960 --> 00:25:22,960 all we need is the width, the height, and a little geometry. 394 00:25:22,960 --> 00:25:26,960 First, we take the frontal view and divide it into parts using geometric shapes 395 00:25:26,960 --> 00:25:30,960 like this. Then, we estimate the area of each geometric 396 00:25:30,960 --> 00:25:34,960 shape and add them together to get the total frontal surface area. 397 00:25:34,960 --> 00:25:38,960 Next, we combine the total frontal surface area with all the flight test 398 00:25:38,960 --> 00:25:42,960 data we've collected and calculate the drag force for this particular model. 399 00:25:42,960 --> 00:25:46,960 We know that to fly, we need a certain amount of thrust to overcome the drag force. 400 00:25:46,960 --> 00:25:50,960 Okay, so figuring out the frontal surface area of the 14% model 401 00:25:50,960 --> 00:25:54,960 helps you calculate drag, which then determines how much thrust is needed. 402 00:25:54,960 --> 00:25:58,960 Right. But this is just a concept airplane, right? I mean, 403 00:25:58,960 --> 00:26:02,960 what if you wanted to add something, maybe like an observation deck on top? 404 00:26:02,960 --> 00:26:06,960 An observation deck would definitely increase the frontal surface 405 00:26:06,960 --> 00:26:10,960 area, Van, which would then increase drag. In order to overcome that amount 406 00:26:10,960 --> 00:26:14,960 of drag, we need to increase thrust by adding more powerful engines. 407 00:26:14,960 --> 00:26:18,960 You know what? That applies to the go-kart race I had with Van. 408 00:26:18,960 --> 00:26:22,960 My frontal surface area was greater than his because 409 00:26:22,960 --> 00:26:26,960 I didn't crouch down into an aerodynamic shape. This greater frontal 410 00:26:26,960 --> 00:26:30,960 surface area created more drag, and I lost. However, 411 00:26:30,960 --> 00:26:34,960 if I had more thrust, I could have easily overcome the drag 412 00:26:34,960 --> 00:26:38,960 and left Van in the dust. Well, you know what? 413 00:26:38,960 --> 00:26:42,960 That's all we have time for today. Yep. We hope you've all made the connection 414 00:26:42,960 --> 00:26:46,960 between the aeronautical research conducted here at NASA and the math, science, and technology 415 00:26:46,960 --> 00:26:50,960 that you do in your classrooms every day. Jennifer and I would love to hear from you 416 00:26:50,960 --> 00:26:54,960 with your questions, comments, or suggestions, so write us at 417 00:26:54,960 --> 00:26:58,960 NASAConnect, NASA Langley Research Center, Mail Stop 400, Hampton, Virginia 418 00:26:58,960 --> 00:27:02,960 23681, or send us an email at connect 419 00:27:02,960 --> 00:27:06,960 at edu.larc.nasa.gov. 420 00:27:06,960 --> 00:27:10,960 Hey, teachers, if you would like a videotape of this program and the accompanying 421 00:27:10,960 --> 00:27:14,960 guide, check out the NASA Connect website. From our site, you can link to 422 00:27:14,960 --> 00:27:18,960 CORE, the NASA Central Operation of Resources for Educators, 423 00:27:18,960 --> 00:27:22,960 or link to the NASA Educator Resource Center Network. 424 00:27:22,960 --> 00:27:26,960 We'd like to thank everyone who helped make this episode of NASA Connect possible, 425 00:27:26,960 --> 00:27:30,960 especially Jackie Chan. No, I thank you, you, and thank you, 426 00:27:30,960 --> 00:27:34,960 Van, and thank you, NASA, for inviting me. I learned a lot of things 427 00:27:34,960 --> 00:27:38,960 because when I was young, the only thing I knew was martial arts. 428 00:27:38,960 --> 00:27:42,960 Kicking, punching, all kinds of things. 429 00:27:42,960 --> 00:27:46,960 I never knew education was important. Whenever I go, 430 00:27:46,960 --> 00:27:50,960 I always support the children because education is very important, remember. 431 00:27:50,960 --> 00:27:54,960 You heard it right from Jackie Chan. We'll see you next time. 432 00:27:54,960 --> 00:27:58,960 Well, to understand flight, you must first under... 433 00:27:58,960 --> 00:28:02,960 That's right, the aerodynamics of... 434 00:28:02,960 --> 00:28:06,960 Now, let's learn 435 00:28:06,960 --> 00:28:10,960 Let's learn how NASA researchers, or NASA engineers, are using 436 00:28:10,960 --> 00:28:14,960 geometry as they... Remember the pictures, 437 00:28:14,960 --> 00:28:18,960 they're a little... We'd like the tank. 438 00:28:18,960 --> 00:28:22,960 So get ready, get set, and flow, 439 00:28:22,960 --> 00:28:26,960 and go, and flow. 440 00:28:26,960 --> 00:28:30,960 ...