1 00:00:00,000 --> 00:00:02,000 Okay, here's the deal. 2 00:00:02,000 --> 00:00:05,000 Van and I are gonna conduct a little experiment about drag 3 00:00:05,000 --> 00:00:07,000 using go-karts. 4 00:00:10,000 --> 00:00:13,000 Van and I are riding in the same kind of go-kart 5 00:00:13,000 --> 00:00:14,000 with the same amount of fuel. 6 00:00:14,000 --> 00:00:16,000 These are constants. 7 00:00:16,000 --> 00:00:19,000 However, Van is taller and heavier than I am. 8 00:00:19,000 --> 00:00:22,000 These two variables, height and weight, 9 00:00:22,000 --> 00:00:23,000 might affect the race. 10 00:00:23,000 --> 00:00:26,000 And hopefully, I'll cross the finish line first. 11 00:00:26,000 --> 00:00:28,000 I am the superior driver. 12 00:00:29,000 --> 00:00:31,000 I can't change my weight. 13 00:00:31,000 --> 00:00:34,000 But if I change the variable of being taller 14 00:00:34,000 --> 00:00:36,000 and crouch down and become more streamlined, 15 00:00:36,000 --> 00:00:38,000 I might have a chance. 16 00:00:51,000 --> 00:00:53,000 No way! 17 00:00:53,000 --> 00:00:55,000 How did you win? 18 00:00:55,000 --> 00:00:57,000 Let me explain, Jennifer. 19 00:00:57,000 --> 00:00:59,000 I changed my shape, which allowed the air to flow 20 00:00:59,000 --> 00:01:01,000 more smoothly around me. 21 00:01:01,000 --> 00:01:04,000 Your shape interrupted the airflow and caused drag. 22 00:01:04,000 --> 00:01:07,000 This slowed you down and allowed me to win. 23 00:01:12,000 --> 00:01:14,000 So, what is drag? 24 00:01:14,000 --> 00:01:17,000 Drag is the force that opposes or resists motion. 25 00:01:17,000 --> 00:01:20,000 The interruption or resistance to airflow causes drag. 26 00:01:20,000 --> 00:01:22,000 You've probably experienced drag when you've ever 27 00:01:22,000 --> 00:01:25,000 stuck your hand out the window of a moving car. 28 00:01:25,000 --> 00:01:27,000 When you extend your arm like this, 29 00:01:27,000 --> 00:01:29,000 with your palm forward, 30 00:01:29,000 --> 00:01:31,000 the force of drag pushes your hand back. 31 00:01:31,000 --> 00:01:33,000 But when you tilt your hand like this, 32 00:01:33,000 --> 00:01:36,000 it creates lift and lifts your hand upward. 33 00:01:36,000 --> 00:01:39,000 Lift and drag are a few of the aerodynamic forces 34 00:01:39,000 --> 00:01:41,000 that act on an airplane when it flies. 35 00:01:41,000 --> 00:01:43,000 How do airplanes fly? 36 00:01:43,000 --> 00:01:45,000 Well, to understand flight, 37 00:01:45,000 --> 00:01:49,000 you must first understand air. 38 00:01:49,000 --> 00:01:54,000 We are surrounded by air all the time, 39 00:01:54,000 --> 00:01:56,000 and we can't feel it because 40 00:01:56,000 --> 00:02:00,000 the air pressure is equal on all sides of our body. 41 00:02:00,000 --> 00:02:03,000 But what if we change the air pressure 42 00:02:03,000 --> 00:02:05,000 on one side of an object? 43 00:02:05,000 --> 00:02:07,000 Check out this cool experiment. 44 00:02:11,000 --> 00:02:13,000 Hey, why did the paper lift up 45 00:02:13,000 --> 00:02:15,000 when I blew across the top? 46 00:02:15,000 --> 00:02:18,000 Well, when the paper is resting against my chin like this, 47 00:02:18,000 --> 00:02:20,000 the air pressure on top is equal 48 00:02:20,000 --> 00:02:22,000 to the air pressure on the bottom. 49 00:02:22,000 --> 00:02:24,000 But when I blow, 50 00:02:24,000 --> 00:02:26,000 I change the air pressure on the top. 51 00:02:26,000 --> 00:02:29,000 The shape of the paper in its original position 52 00:02:29,000 --> 00:02:31,000 is kind of like an airplane's wing. 53 00:02:31,000 --> 00:02:33,000 It is curved on the top. 54 00:02:33,000 --> 00:02:35,000 Because of this shape, 55 00:02:35,000 --> 00:02:37,000 air molecules move faster across the wing's top 56 00:02:37,000 --> 00:02:39,000 than across its bottom. 57 00:02:39,000 --> 00:02:41,000 Swiss mathematician Daniel Bernoulli 58 00:02:41,000 --> 00:02:43,000 discovered that faster-moving fluids, 59 00:02:43,000 --> 00:02:45,000 such as air, 60 00:02:45,000 --> 00:02:48,000 exert less pressure than slower-moving fluids. 61 00:02:48,000 --> 00:02:50,000 Because of its shape, 62 00:02:50,000 --> 00:02:52,000 the air on top of the wing moves more quickly 63 00:02:52,000 --> 00:02:54,000 and exerts less pressure. 64 00:02:54,000 --> 00:02:56,000 When the pressure on top of the wing 65 00:02:56,000 --> 00:02:58,000 is less than the pressure under the wing, 66 00:02:58,000 --> 00:03:01,000 lift is produced, and the airplane flies. 67 00:03:01,000 --> 00:03:04,000 What does all this have to do with algebra and geometry? 68 00:03:04,000 --> 00:03:06,000 Everything! 69 00:03:06,000 --> 00:03:08,000 Geometry is the study of shape and size. 70 00:03:08,000 --> 00:03:10,000 Geometry was probably first developed 71 00:03:10,000 --> 00:03:13,000 to help measure the Earth and its objects. 72 00:03:13,000 --> 00:03:16,000 Knowledge of geometry helps you better understand things 73 00:03:16,000 --> 00:03:18,000 like engineering and science. 74 00:03:18,000 --> 00:03:21,000 Algebra is a mathematical tool for solving problems. 75 00:03:21,000 --> 00:03:24,000 Learning algebra is a bit like learning to read and write. 76 00:03:24,000 --> 00:03:27,000 Knowledge of algebra can give you more power 77 00:03:27,000 --> 00:03:30,000 to solve problems and accomplish what you want in life. 78 00:03:30,000 --> 00:03:33,000 At NASA, engineers use algebra and geometry 79 00:03:33,000 --> 00:03:35,000 when they measure and design models 80 00:03:35,000 --> 00:03:37,000 to be tested in wind tunnels. 81 00:03:37,000 --> 00:03:39,000 Like today's NASA engineers, 82 00:03:39,000 --> 00:03:42,000 Orville and Wilbur Wright used algebra and geometry. 83 00:03:42,000 --> 00:03:44,000 By blowing a certain amount of air 84 00:03:44,000 --> 00:03:46,000 over models in a wind tunnel, 85 00:03:46,000 --> 00:03:49,000 they tested and compared different wing shapes, 86 00:03:49,000 --> 00:03:51,000 rudder shapes, and propeller shapes. 87 00:03:51,000 --> 00:03:53,000 Hey, let's conduct an experiment 88 00:03:53,000 --> 00:03:55,000 very similar to the Wright brothers 89 00:03:55,000 --> 00:03:57,000 and test different shapes for drag. 90 00:03:57,000 --> 00:03:59,000 Good idea, Van, but first, teachers, 91 00:03:59,000 --> 00:04:01,000 make sure you check out the NASA Connect website 92 00:04:01,000 --> 00:04:03,000 and download the lesson guide for today's program. 93 00:04:03,000 --> 00:04:05,000 In it, you'll find step-by-step instructions 94 00:04:05,000 --> 00:04:07,000 and analysis questions for today's classroom activity. 95 00:04:07,000 --> 00:04:08,000 Van?