1 00:00:30,000 --> 00:00:48,360 Hi, I'm Jennifer Pulley, and welcome to NASA Connect, the show that connects you to the 2 00:00:48,360 --> 00:00:52,360 world of math, science, technology, and NASA. 3 00:00:52,360 --> 00:00:58,640 Today, we're at NASA Glenn Research Center in Cleveland, Ohio, and this is the Zero Gravity 4 00:00:58,640 --> 00:01:02,880 Facility, and it's where NASA conducts microgravity experiments. 5 00:01:02,880 --> 00:01:04,400 You've seen microgravity. 6 00:01:04,400 --> 00:01:13,240 You've seen it in videos of the International Space Station and on NASA's KC-135. 7 00:01:13,240 --> 00:01:18,280 On today's program, we'll investigate how NASA researchers conduct research in a microgravity 8 00:01:18,280 --> 00:01:19,280 environment. 9 00:01:19,280 --> 00:01:24,240 You'll observe NASA researchers using the math concepts of measurement, ratios, and 10 00:01:24,240 --> 00:01:29,840 graphing to research combustion science and the importance of fire safety on the International 11 00:01:29,840 --> 00:01:30,840 Space Station. 12 00:01:30,840 --> 00:01:37,240 In your classroom, you'll do a cool hands-on activity to learn more about gravity by collecting, 13 00:01:37,240 --> 00:01:40,560 organizing, graphing, and analyzing data. 14 00:01:40,560 --> 00:01:45,280 And using the instructional technology activity, you will investigate apparent weight to see 15 00:01:45,280 --> 00:01:48,840 how astronauts in space can feel weightless. 16 00:01:48,840 --> 00:01:53,680 NASA researchers use the math concepts of ratios, measurement, and graphing all the 17 00:01:53,680 --> 00:01:54,680 time. 18 00:01:54,680 --> 00:01:56,840 First, let's review ratios. 19 00:01:56,840 --> 00:01:59,960 A ratio is a comparison of two quantities. 20 00:01:59,960 --> 00:02:04,800 For example, NASA Glenn Research Center and NASA Marshall Space Flight Center, which are 21 00:02:04,800 --> 00:02:11,040 the NASA facilities that primarily conduct microgravity research, are two of ten NASA 22 00:02:11,040 --> 00:02:13,600 centers located across the country. 23 00:02:13,600 --> 00:02:19,120 A ratio can be written as a fraction, and it can be written in any form that is equal 24 00:02:19,120 --> 00:02:21,440 or equivalent to that fraction. 25 00:02:21,440 --> 00:02:29,160 So the ratio two-tenths can also be written as two is to ten, twenty percent, twenty-one-hundredths, 26 00:02:29,160 --> 00:02:30,160 and point-two-zero. 27 00:02:30,160 --> 00:02:35,880 When you work with ratios, you can express fractions, decimals, and percentages. 28 00:02:35,880 --> 00:02:41,280 To learn how NASA researchers apply the concept of ratios to the microgravity environment, 29 00:02:41,280 --> 00:02:43,320 let's go see Dr. Roger Crouch. 30 00:02:43,320 --> 00:02:46,800 He's the senior scientist for the International Space Station. 31 00:02:46,800 --> 00:02:49,280 Hey, Dr. Crouch. 32 00:02:49,280 --> 00:02:50,800 Hello, Jennifer. 33 00:02:50,800 --> 00:02:56,240 Math is very important to everyone, but especially to scientists and engineers. 34 00:02:56,240 --> 00:03:00,200 We use ratios in every aspect of research in a microgravity environment. 35 00:03:00,200 --> 00:03:03,240 So, Dr. Crouch, what is microgravity? 36 00:03:03,240 --> 00:03:07,360 Microgravity is a condition where the effects of gravity are, or appear to be, very much 37 00:03:07,360 --> 00:03:10,000 smaller than they normally are here on Earth. 38 00:03:10,000 --> 00:03:14,320 The prefix micro comes from the Greek root mikros, which simply means small. 39 00:03:14,320 --> 00:03:19,840 However, in the scientific metric system, micro literally means one part in a million, 40 00:03:19,840 --> 00:03:21,960 or one to one million. 41 00:03:21,960 --> 00:03:26,500 We use the term microgravity to describe the environment on board a spacecraft in orbit 42 00:03:26,500 --> 00:03:28,160 around the Earth. 43 00:03:28,160 --> 00:03:29,160 Gravity is everywhere. 44 00:03:29,160 --> 00:03:33,080 We usually call it high gravity if it's more than here on Earth, and low gravity if it's 45 00:03:33,080 --> 00:03:34,520 less than here on Earth. 46 00:03:34,520 --> 00:03:37,240 An example of a low-gravity environment would be the Moon. 47 00:03:37,240 --> 00:03:40,240 The gravity on the Moon is about one-sixth of that here on Earth. 48 00:03:40,240 --> 00:03:41,240 Hey! 49 00:03:41,240 --> 00:03:42,240 One-sixth? 50 00:03:42,240 --> 00:03:43,240 That's a ratio. 51 00:03:43,240 --> 00:03:44,240 That's right. 52 00:03:44,240 --> 00:03:47,040 What are the quantities being compared in this statement? 53 00:03:47,040 --> 00:03:50,160 The gravity of the Moon is about one-sixth that on Earth. 54 00:03:50,160 --> 00:03:55,320 If you said the Moon's gravity to the Earth's gravity, then you're starting to understand 55 00:03:55,320 --> 00:03:56,320 ratios. 56 00:03:56,320 --> 00:04:00,200 The ratio one-sixth means that the gravity of the Moon is six times smaller than the 57 00:04:00,200 --> 00:04:01,800 gravity on Earth. 58 00:04:01,800 --> 00:04:05,640 We sometimes use the term microgravity to describe a condition where gravity is not 59 00:04:05,640 --> 00:04:08,240 small, but appears to be small. 60 00:04:08,240 --> 00:04:11,880 This is a condition experienced on orbiting spacecraft such as the International Space 61 00:04:11,880 --> 00:04:17,080 Station, or ISS, the Space Shuttle, and all objects in free fall. 62 00:04:17,080 --> 00:04:20,120 That's me appearing to float inside the Space Shuttle. 63 00:04:20,120 --> 00:04:24,000 Really I'm not floating, but falling at the same rate as the Shuttle, so to the observer 64 00:04:24,000 --> 00:04:25,800 it looks like I'm floating. 65 00:04:25,800 --> 00:04:28,840 So microgravity is not really zero gravity. 66 00:04:28,840 --> 00:04:29,840 That's right. 67 00:04:29,840 --> 00:04:33,360 It diminishes relatively quickly with distance, so it's weaker on the Space Station than it 68 00:04:33,360 --> 00:04:34,360 is on Earth. 69 00:04:34,560 --> 00:04:38,920 But it's 6,400 kilometers from the surface to the center of the Earth, which is considered 70 00:04:38,920 --> 00:04:41,360 the origin of the Earth's gravity field. 71 00:04:41,360 --> 00:04:45,360 Then the ISS is only another 400 kilometers above the surface of the Earth. 72 00:04:45,360 --> 00:04:52,360 So at that altitude, the gravitational acceleration is still about 89 percent, or 89 one-hundredths, 73 00:04:52,360 --> 00:04:53,880 of that of the Earth's surface. 74 00:04:53,880 --> 00:04:59,360 If the gravitational acceleration on the surface of the Earth is 9.8 meters per second squared, 75 00:04:59,360 --> 00:05:04,360 what would the gravitational acceleration be 400 kilometers above the surface of the 76 00:05:04,360 --> 00:05:05,360 Earth? 77 00:05:05,360 --> 00:05:06,360 Let's see. 78 00:05:06,360 --> 00:05:12,000 You would approximate the gravitational acceleration at 400 kilometers above the Earth's surface 79 00:05:12,000 --> 00:05:16,360 by calculating the product of 9.8 and .89, or 89 one-hundredths. 80 00:05:16,360 --> 00:05:17,360 That's correct. 81 00:05:17,360 --> 00:05:23,860 By multiplying 9.8 and .89, we see that the gravitational acceleration at 400 kilometers 82 00:05:23,860 --> 00:05:28,360 above the Earth's surface is about 8.7 meters per second squared. 83 00:05:28,360 --> 00:05:34,360 Comparing 9.8 and 8.7 meters per second squared, gravity at the altitude of the ISS is nearly 84 00:05:34,360 --> 00:05:36,360 the same as that on Earth. 85 00:05:36,360 --> 00:05:40,360 But given the images of floating astronauts, it appears that gravity is reduced by much 86 00:05:40,360 --> 00:05:42,360 more than 11 percent. 87 00:05:42,360 --> 00:05:44,360 So Dr. Crouch, what is happening here? 88 00:05:44,360 --> 00:05:48,360 Gravity attracts all objects towards the center of the Earth at the same rate. 89 00:05:48,360 --> 00:05:53,360 If I release two objects of different weight, and they have room to fall, they will accelerate 90 00:05:53,360 --> 00:05:56,360 towards the center of the Earth at the same rate until they meet the resistance in the 91 00:05:56,360 --> 00:05:57,360 form of the floor, for instance. 92 00:05:57,360 --> 00:06:00,360 In other words, they'll hit the floor at the same time. 93 00:06:00,360 --> 00:06:03,360 It's the force of the floor that we feel is our weight. 94 00:06:03,360 --> 00:06:08,360 When gravity is the only force acting on an object, then it is said to be in a state called 95 00:06:08,360 --> 00:06:09,360 free fall. 96 00:06:09,360 --> 00:06:12,360 Objects in free fall can be said to be weightless. 97 00:06:12,360 --> 00:06:16,360 Imagine you have an apple on a scale which displays the apple's weight. 98 00:06:16,360 --> 00:06:20,360 If you drop the scale, the apple and the scale will fall together, but the apple will no 99 00:06:20,360 --> 00:06:24,360 longer compress the scale, so the scale will show zero weight. 100 00:06:24,360 --> 00:06:30,360 In the same way, astronauts inside the ISS or the space show are falling around the Earth. 101 00:06:30,360 --> 00:06:35,360 Unlike the apple on the scale, both the astronauts and the spacecraft free fall by circling the 102 00:06:35,360 --> 00:06:41,360 Earth at approximately 7,870 meters per second, or 17,000 miles per hour. 103 00:06:41,360 --> 00:06:44,360 They're falling towards the Earth, they just never get there. 104 00:06:44,360 --> 00:06:49,360 How are the concepts of measurement and graphing important to NASA researchers and scientists? 105 00:06:49,360 --> 00:06:53,360 Research in the space environment gives scientists a new tool for looking at phenomena in ways 106 00:06:53,360 --> 00:06:56,360 that are just not possible here on Earth. 107 00:06:56,360 --> 00:07:01,360 But these discoveries won't take place without understanding and applying the math concepts 108 00:07:01,360 --> 00:07:03,360 of measurement and graphing. 109 00:07:03,360 --> 00:07:08,360 To demonstrate how scientists and researchers use these concepts, Dr. Sandra Olson, a microgravity 110 00:07:08,360 --> 00:07:12,360 combustion scientist at the NASA Glenn Research Center, will tell us more. 111 00:07:12,360 --> 00:07:14,360 Oh, great. Thank you so much, Dr. Crouch. 112 00:07:14,360 --> 00:07:16,360 Thank you, Jennifer. I enjoyed it. 113 00:07:16,360 --> 00:07:21,360 Now, before we visit Dr. Olson, let's review the math concepts of measurement and graphing. 114 00:07:21,360 --> 00:07:27,360 Measurement. It usually tells us the size of something and consists of a number and a unit. 115 00:07:27,360 --> 00:07:35,360 For example, the gravitational acceleration at the surface of the Earth is 9.8 meters per second squared. 116 00:07:35,360 --> 00:07:40,360 9.8 is the number, and meters per second squared is the unit. 117 00:07:40,360 --> 00:07:45,360 The unit in the measurement is a fixed quantity with a size that is understood. 118 00:07:45,360 --> 00:07:49,360 The number in a measurement tells how many units there are in what is being measured. 119 00:07:49,360 --> 00:07:54,360 This allows us to compare the size of what's being measured to the size of the unit. 120 00:07:54,360 --> 00:08:02,360 For example, Dr. Crouch indicated that the gravitational acceleration 400 kilometers above the Earth's surface 121 00:08:02,360 --> 00:08:10,360 is 8.7 meters per second squared units compared to the gravitational acceleration at the Earth's surface, 122 00:08:10,360 --> 00:08:14,360 which is 9.8 meters per second squared units. 123 00:08:14,360 --> 00:08:18,360 Notice that the unit of measurement is the same for both numbers. 124 00:08:18,360 --> 00:08:23,360 And in case you're wondering, what does the unit meters per second squared mean? 125 00:08:23,360 --> 00:08:28,360 Well, one meter per second squared, or one meter per second per second, 126 00:08:28,360 --> 00:08:34,360 means that for every second of travel, the velocity increases by one meter per second. 127 00:08:34,360 --> 00:08:40,360 So, if the acceleration due to gravity is 9.8 meters per second squared, 128 00:08:40,360 --> 00:08:46,360 then for every second of travel, the velocity increases by 9.8 meters per second. 129 00:08:46,360 --> 00:08:50,360 Okay, guys, the next math concept for today's show is graphing. 130 00:08:50,360 --> 00:08:56,360 And graphing is really important because it creates a visual representation of relationships 131 00:08:56,360 --> 00:08:59,360 that may not be easily determined using numbers alone. 132 00:08:59,360 --> 00:09:03,360 And there are many different types of graphs that can be used to visually represent data. 133 00:09:03,360 --> 00:09:11,360 There are bar graphs, circle graphs, line graphs, pictographs, and scatter plots, just to name a few. 134 00:09:11,360 --> 00:09:18,360 Remember when Dr. Crouch told us that gravity diminishes as we get farther and farther away from the Earth? 135 00:09:18,360 --> 00:09:21,360 We can represent this visually with a graph. 136 00:09:21,360 --> 00:09:25,360 The x-axis, or horizontal axis, represents distance, 137 00:09:25,360 --> 00:09:30,360 and the y-axis, or vertical axis, represents gravity. 138 00:09:30,360 --> 00:09:35,360 From the graph, you can see that gravity decreases with increasing distance. 139 00:09:35,360 --> 00:09:38,360 So, are you with me so far? 140 00:09:38,360 --> 00:09:43,360 Good. Let's go chat with Dr. Sandra Olson here at NASA Glenn Research Center. 141 00:09:46,360 --> 00:09:49,360 How do fires in space travel differently from fires on Earth? 142 00:09:49,360 --> 00:09:54,360 From the position versus time graph, what type of relationship exists from the flame widths? 143 00:09:54,360 --> 00:09:58,360 What does the slope of a position versus time graph tell you? 144 00:09:58,360 --> 00:09:59,360 Hey, Dr. Olson. 145 00:09:59,360 --> 00:10:00,360 Hello, Jennifer. 146 00:10:00,360 --> 00:10:03,360 I'm glad you're able to come and see our facility today. 147 00:10:03,360 --> 00:10:07,360 Thank you for asking me to explain how we use measurement and graphing techniques in our research. 148 00:10:07,360 --> 00:10:10,360 So, what kind of research do you do here? 149 00:10:10,360 --> 00:10:15,360 I do experiments in microgravity combustion, especially as it relates to spacecraft fire safety. 150 00:10:15,360 --> 00:10:18,360 You know, Jennifer, we're told as children that if there's a fire in our house, 151 00:10:18,360 --> 00:10:21,360 we're supposed to get out of the house and call the fire department. 152 00:10:21,360 --> 00:10:23,360 But in spacecraft, this isn't an option. 153 00:10:23,360 --> 00:10:27,360 There are no fire departments in space, and you just can't walk outside. 154 00:10:27,360 --> 00:10:31,360 A bad fire actually happened on the Russian Mir space station in 1997. 155 00:10:31,360 --> 00:10:34,360 We need to understand fire behavior in microgravity 156 00:10:34,360 --> 00:10:39,360 so that we will know how to avoid the fire as much as possible and survive it if it does occur. 157 00:10:39,360 --> 00:10:45,360 Now, Dr. Olson, it sounds to me like you're saying that fire behaves differently in space than it does here on Earth. 158 00:10:45,360 --> 00:10:47,360 Very differently, Jennifer. 159 00:10:47,360 --> 00:10:51,360 Gravity is such a dominant force in fires here on Earth that we take it for granted. 160 00:10:51,360 --> 00:10:54,360 For example, a wildfire is very gravity dependent. 161 00:10:54,360 --> 00:10:58,360 On Earth, wildfires spread uphill much faster than downhill. 162 00:10:58,360 --> 00:11:03,360 The reason for this is that the heated air from the fire rises up the hill and heats the fuel, 163 00:11:03,360 --> 00:11:06,360 like the grass, trees, and shrubs, ahead of the fire. 164 00:11:06,360 --> 00:11:12,360 Blown into the wind, the fire's reach is long, and it can spread very fast over the nice, warm fuel. 165 00:11:12,360 --> 00:11:19,360 On the other hand, going downhill, the wind is fresh, cool air being drawn into the fire to replace the rising hot gases. 166 00:11:19,360 --> 00:11:23,360 The vegetation remains cool until the flames are very close. 167 00:11:23,360 --> 00:11:29,360 The flame's reach is very short, and it takes longer to heat up the cold fuel, and the flame spreads more slowly. 168 00:11:29,360 --> 00:11:33,360 In space, fires like to go in the exact opposite direction. 169 00:11:33,360 --> 00:11:37,360 They like to spread against the wind, while wildfires are blown by the wind. 170 00:11:37,360 --> 00:11:41,360 Because hot air doesn't rise in a microgravity environment, 171 00:11:41,360 --> 00:11:48,360 the only air flows in an orbiting spacecraft come from ventilation fans, cooling fans, and crew movements. 172 00:11:48,360 --> 00:11:55,360 A fire, given a choice in this microgravity environment, will preferentially spread into the fresh air. 173 00:11:55,360 --> 00:11:59,360 The flame doesn't have any control over the airflow, so it has to seek out the fresh air. 174 00:11:59,360 --> 00:12:06,360 The windblown, or downwind side of the flame, is only receiving polluted air that contains smoke and carbon dioxide, 175 00:12:06,360 --> 00:12:11,360 but not much oxygen, because that's already been consumed by the upwind side of the flame. 176 00:12:11,360 --> 00:12:17,360 So when the air flows from the ventilation fans are low, the downwind side of the flame can't spread at all, 177 00:12:17,360 --> 00:12:20,360 even though it has fuel and heat, it doesn't have the oxygen. 178 00:12:20,360 --> 00:12:24,360 In a microgravity environment, if we reduce the airflow, 179 00:12:24,360 --> 00:12:30,360 even the oxygen-seeking upwind side of the flame has trouble getting enough oxygen, and it breaks up into little flamelets. 180 00:12:30,360 --> 00:12:35,360 Okay, so how do you measure, or collect data on these little flamelets? 181 00:12:35,360 --> 00:12:40,360 In our experiments, we use this droppable wind tunnel to study the effect of airflow on the flamelets. 182 00:12:40,360 --> 00:12:46,360 When we drop this miniature wind tunnel, we can get brief periods of microgravity here on Earth. 183 00:12:46,360 --> 00:12:53,360 We can measure the effect of airflow on the flame by applying a very low-speed airflow to a flame as it spreads across a thin sheet of paper. 184 00:12:53,360 --> 00:13:00,360 As it spreads, we can measure its position as a function of time, and plot time and position on a graph. 185 00:13:00,360 --> 00:13:05,360 The following graph allows us to compare position versus time for flamelet tracking. 186 00:13:05,360 --> 00:13:10,360 The x-axis, or horizontal axis, is the time measured in seconds, 187 00:13:10,360 --> 00:13:15,360 and the y-axis, or vertical axis, is the position of the flame measured in millimeters. 188 00:13:15,360 --> 00:13:22,360 This graph represents a flame that starts out uniform, and after five seconds of travel, breaks up into flamelets. 189 00:13:22,360 --> 00:13:28,360 The point 0,0 represents the location where the uniform flame breaks up into flamelets. 190 00:13:28,360 --> 00:13:35,360 Okay, Dr. Olson, from this graph, there appears to be a linear relationship between position and time. 191 00:13:35,360 --> 00:13:41,360 Why is the slope of the line representing the uniform flame steeper than the line representing the flamelets? 192 00:13:41,360 --> 00:13:43,360 That's a great question, Jennifer. 193 00:13:43,360 --> 00:13:48,360 The steepness, or slope, of the line tells us the spread rate, or the velocity, of the flame. 194 00:13:48,360 --> 00:13:54,360 So let me see if I get this. As the slope of the line decreases, then the spread rate, or velocity, decreases. 195 00:13:54,360 --> 00:14:02,360 That's correct. For this particular test run, the velocity of the uniform flame was calculated to be 3.4 millimeters per second, 196 00:14:02,360 --> 00:14:07,360 and the velocity of the flamelets was calculated to be 1.0 millimeters per second. 197 00:14:07,360 --> 00:14:11,360 Although the flamelets spread more slowly, they're very hard to detect, 198 00:14:11,360 --> 00:14:15,360 and they can flare up into a big fire again if we turn up the airflow. 199 00:14:15,360 --> 00:14:21,360 Imagine if the astronauts put out a fire and then turned on the air circulation system to clean up the smoke. 200 00:14:21,360 --> 00:14:23,360 The fire could flare up again. 201 00:14:23,360 --> 00:14:30,360 Wow, I can see how important your research is to the safety of the astronauts on board the International Space Station and the Space Shuttle. 202 00:14:30,360 --> 00:14:32,360 Thank you so much, Dr. Olson. 203 00:14:32,360 --> 00:14:33,360 Thank you, Jennifer. 204 00:14:33,360 --> 00:14:36,360 Hey kids, it's now time for a cue card review. 205 00:14:37,360 --> 00:14:40,360 How do fires in space travel differently than fires on Earth? 206 00:14:40,360 --> 00:14:45,360 From the position versus time graph, what type of relationship exists from the flamelets? 207 00:14:45,360 --> 00:14:48,360 What does the slope of a position versus time graph tell you? 208 00:14:50,360 --> 00:14:55,360 Okay, let's review. We highlighted the math concepts of ratios, measurement, and graphing. 209 00:14:55,360 --> 00:15:00,360 Dr. Crouch applied the concept of ratios to help us define microgravity. 210 00:15:00,360 --> 00:15:07,360 And Dr. Olson explained the importance of measurement and graphing while conducting spacecraft fire safety research. 211 00:15:07,360 --> 00:15:11,360 Now it's your turn to apply these math concepts in your classroom. 212 00:15:11,360 --> 00:15:14,360 Check out this program's awesome hands-on activity. 213 00:15:17,360 --> 00:15:21,360 Hi, we're students at Northside Middle School here in Norfolk, Virginia. 214 00:15:21,360 --> 00:15:25,360 NASA Connect asked us to show you this program's hands-on activity. 215 00:15:25,360 --> 00:15:29,360 You can download a lesson guide and a list of materials from the NASA Connect website. 216 00:15:29,360 --> 00:15:31,360 Here are the main objectives. 217 00:15:31,360 --> 00:15:35,360 Students will apply techniques to determine measurements, 218 00:15:35,360 --> 00:15:37,360 use metric measurement, 219 00:15:37,360 --> 00:15:42,360 build mathematical knowledge through investigation and experimentation, 220 00:15:42,360 --> 00:15:46,360 collect, organize, and graph data for analysis, 221 00:15:46,360 --> 00:15:49,360 build an understanding of microgravity. 222 00:15:50,360 --> 00:15:51,360 Good morning, class. 223 00:15:51,360 --> 00:15:58,360 Today, NASA has asked us to investigate how graphing techniques are helpful in understanding the concepts of position, 224 00:15:58,360 --> 00:16:00,360 velocity, and acceleration. 225 00:16:00,360 --> 00:16:04,360 Teachers will find a location for dropping pre-selected objects. 226 00:16:04,360 --> 00:16:09,360 A set of bleachers provides a good variation in heights without using ladders. 227 00:16:09,360 --> 00:16:13,360 Mark the drop location in even increments, if possible. 228 00:16:13,360 --> 00:16:18,360 Eight to ten drop stations create a good graph that students can easily view. 229 00:16:18,360 --> 00:16:25,360 Measure each station in meters or inches and use the conversion one meter equals 3.281 feet. 230 00:16:25,360 --> 00:16:27,360 Organize students into groups of four. 231 00:16:27,360 --> 00:16:31,360 Once each group has selected a different ball to use for all their test drops, 232 00:16:31,360 --> 00:16:33,360 distribute the student materials. 233 00:16:33,360 --> 00:16:38,360 A student recorder writes down the height of each drop station on the data collection chart. 234 00:16:38,360 --> 00:16:42,360 A student timer records five drops at each drop station. 235 00:16:42,360 --> 00:16:47,360 Only the ball dropper should climb to the drop site, with the rest remaining at ground level. 236 00:16:47,360 --> 00:16:53,360 The student counter returns the ball to the dropper and begins the countdown again when everyone is ready. 237 00:16:53,360 --> 00:16:58,360 Average the times for each drop station and record on the data collection chart. 238 00:16:58,360 --> 00:17:03,360 Square the average times for each drop station and record on the data collection chart. 239 00:17:03,360 --> 00:17:06,360 Using height and average time data for each drop station, 240 00:17:06,360 --> 00:17:09,360 plot a distance vs. time graph on Drop Data Chart 1. 241 00:17:09,360 --> 00:17:13,360 Using height and average squared time data for each drop station, 242 00:17:13,360 --> 00:17:18,360 plot a distance vs. time squared graph on Drop Data Chart 2. 243 00:17:18,360 --> 00:17:21,360 The teacher will collect the drop data charts from each group 244 00:17:21,360 --> 00:17:24,360 and compare the data on Drop Data Chart 1 for each ball 245 00:17:24,360 --> 00:17:27,360 and discuss the shape the data points create. 246 00:17:27,360 --> 00:17:33,360 Next, overlay all Drop Data Chart 1 transparencies to compare the data simultaneously. 247 00:17:33,360 --> 00:17:37,360 In the next comparison, compare the data on Drop Data Chart 2 for each ball 248 00:17:37,360 --> 00:17:40,360 and discuss the shape the data points create. 249 00:17:40,360 --> 00:17:46,360 Again, overlay all Drop Data Chart 2 transparencies to compare the data simultaneously. 250 00:17:46,360 --> 00:17:47,360 It's time for questions. 251 00:17:47,360 --> 00:17:51,360 Based on your observations, predict what will happen to the acceleration 252 00:17:51,360 --> 00:17:54,360 if the object is dropped from a greater height. 253 00:17:56,360 --> 00:17:57,360 Christine. 254 00:17:57,360 --> 00:18:00,360 I don't think it'll matter where you drop the ball from the bleachers. 255 00:18:00,360 --> 00:18:02,360 The acceleration will stay the same. 256 00:18:02,360 --> 00:18:03,360 Great answer. 257 00:18:03,360 --> 00:18:04,360 Mr. Coppola. 258 00:18:04,360 --> 00:18:05,360 Thank you. 259 00:18:05,360 --> 00:18:10,360 Did the shape or surface of the object dropped have any effect on the results? 260 00:18:10,360 --> 00:18:11,360 Explain. 261 00:18:12,360 --> 00:18:13,360 John. 262 00:18:13,360 --> 00:18:16,360 I don't think that it would have any effect on this experiment 263 00:18:16,360 --> 00:18:20,360 because we're using an object such as a ball and the air resistance is negligible. 264 00:18:20,360 --> 00:18:24,360 But, on the other hand, if we were to use an object such as a piece of paper, 265 00:18:24,360 --> 00:18:27,360 it would float down and take longer to hit the ground. 266 00:18:27,360 --> 00:18:30,360 Teachers, if you would like help to perform the preceding lesson 267 00:18:30,360 --> 00:18:32,360 or any other NASA Connect lesson, 268 00:18:32,360 --> 00:18:35,360 simply enlist the help of an AIAA mentor 269 00:18:35,360 --> 00:18:38,360 who will be glad to assist your class in these activities. 270 00:18:39,360 --> 00:18:41,360 Super job, you guys. 271 00:18:41,360 --> 00:18:45,360 Hey, did you know that NASA is working with students 272 00:18:45,360 --> 00:18:49,360 to develop new products and new experiments for space research? 273 00:18:49,360 --> 00:18:53,360 Dr. John Poiman, a professor of chemistry and biochemistry 274 00:18:53,360 --> 00:18:55,360 at the University of Southern Mississippi, 275 00:18:55,360 --> 00:18:58,360 has some cool applications for microgravity research, 276 00:18:58,360 --> 00:19:01,360 which students just like you can be working on someday. 277 00:19:02,360 --> 00:19:04,360 What is going to induce convection? 278 00:19:04,360 --> 00:19:07,360 What is the relationship between density and volume? 279 00:19:07,360 --> 00:19:10,360 What is the trend in the density versus temperature graph? 280 00:19:11,360 --> 00:19:12,360 Hi. 281 00:19:12,360 --> 00:19:15,360 NASA's Reduced Gravity Program began in 1959, 282 00:19:15,360 --> 00:19:17,360 but in the past five years, 283 00:19:17,360 --> 00:19:19,360 students from over 100 schools 284 00:19:19,360 --> 00:19:22,360 have performed experiments in a microgravity environment. 285 00:19:22,360 --> 00:19:25,360 Several of my students and I have flown on the KC-137 286 00:19:25,360 --> 00:19:27,360 and the KC-138, 287 00:19:28,360 --> 00:19:32,360 Several of my students and I have flown on the KC-135, 288 00:19:32,360 --> 00:19:34,360 NASA's flying laboratory. 289 00:19:34,360 --> 00:19:37,360 It's science that's interesting, challenging, and fun. 290 00:19:37,360 --> 00:19:39,360 One experiment we are conducting 291 00:19:39,360 --> 00:19:41,360 involves making new space-age materials 292 00:19:41,360 --> 00:19:45,360 by a really cool process called frontal polymerization, 293 00:19:45,360 --> 00:19:48,360 and the other involves studying how molecules attract each other 294 00:19:48,360 --> 00:19:50,360 in fluids that mix. 295 00:19:50,360 --> 00:19:53,360 Everything is made up of very, very small pieces of stuff 296 00:19:53,360 --> 00:19:54,360 called molecules. 297 00:19:54,360 --> 00:19:56,360 Molecules attract each other. 298 00:19:56,360 --> 00:19:57,360 How strongly they attract 299 00:19:57,360 --> 00:20:00,360 determines if the stuff is a liquid, solid, or a gas. 300 00:20:00,360 --> 00:20:02,360 Some materials mix completely. 301 00:20:02,360 --> 00:20:03,360 Others do not. 302 00:20:03,360 --> 00:20:05,360 Here's something you can try at home yourself. 303 00:20:05,360 --> 00:20:08,360 We have water here, which has food coloring in it, 304 00:20:08,360 --> 00:20:09,360 and syrup. 305 00:20:09,360 --> 00:20:13,360 And as I pour the syrup in 306 00:20:13,360 --> 00:20:15,360 and stir it up, 307 00:20:15,360 --> 00:20:20,360 it'll make one continuous liquid. 308 00:20:20,360 --> 00:20:22,360 But if I take something that's immiscible with water, 309 00:20:22,360 --> 00:20:24,360 like mineral oil, 310 00:20:24,360 --> 00:20:28,360 and pour it into the water with food coloring 311 00:20:28,360 --> 00:20:31,360 and mix this solution up, 312 00:20:31,360 --> 00:20:34,360 it will separate into two layers with time. 313 00:20:34,360 --> 00:20:37,360 Water molecules attract each other more strongly 314 00:20:37,360 --> 00:20:38,360 than they attract oil molecules, 315 00:20:38,360 --> 00:20:40,360 and so the water stays separate. 316 00:20:40,360 --> 00:20:42,360 A monomer is a small molecule 317 00:20:42,360 --> 00:20:44,360 that can be made to form long chains of monomers 318 00:20:44,360 --> 00:20:47,360 connected end-to-end called a polymer. 319 00:20:47,360 --> 00:20:49,360 It's sort of like boxcars hooked together to form a train. 320 00:20:49,360 --> 00:20:52,360 The mixing process is called convection. 321 00:20:52,360 --> 00:20:54,360 It's the term for liquid motion. 322 00:20:54,360 --> 00:20:56,360 There are two ways in which convection 323 00:20:56,360 --> 00:20:58,360 can spontaneously occur in a liquid. 324 00:20:58,360 --> 00:20:59,360 One is caused by gravity, 325 00:20:59,360 --> 00:21:02,360 and it's called buoyancy-induced convection. 326 00:21:02,360 --> 00:21:05,360 Differences between the densities of the liquids 327 00:21:05,360 --> 00:21:06,360 make the lighter fluid rise 328 00:21:06,360 --> 00:21:08,360 and separate from the heavier fluid. 329 00:21:08,360 --> 00:21:10,360 Another type of convection 330 00:21:10,360 --> 00:21:13,360 is called interfacial tension-induced convection. 331 00:21:13,360 --> 00:21:14,360 Interfacial what? 332 00:21:14,360 --> 00:21:16,360 Interfacial tension-induced convection. 333 00:21:16,360 --> 00:21:18,360 Let's split the term up. 334 00:21:18,360 --> 00:21:21,360 First, interfacial tension is like the surface tension, 335 00:21:21,360 --> 00:21:24,360 which holds up a water bug when it skitters across a pond. 336 00:21:24,360 --> 00:21:27,360 The surface is the result of the water molecules 337 00:21:27,360 --> 00:21:28,360 attracting each other. 338 00:21:28,360 --> 00:21:30,360 But heating a surface here on Earth 339 00:21:30,360 --> 00:21:32,360 causes buoyancy-induced convection. 340 00:21:32,360 --> 00:21:34,360 How can we study only the convection 341 00:21:34,360 --> 00:21:36,360 caused by interfacial effects alone? 342 00:21:36,360 --> 00:21:39,360 We need to eliminate gravity or its effects. 343 00:21:39,360 --> 00:21:41,360 We can never eliminate gravity, 344 00:21:41,360 --> 00:21:43,360 but by free-falling, we can create a system 345 00:21:43,360 --> 00:21:46,360 that acts as if there were no gravity. 346 00:21:46,360 --> 00:21:48,360 Performing experiments in weightlessness 347 00:21:48,360 --> 00:21:51,360 allows us to study phenomena we can't study on Earth 348 00:21:51,360 --> 00:21:54,360 and to answer questions we can't answer down here. 349 00:21:54,360 --> 00:21:56,360 By eliminating buoyancy-induced convection, 350 00:21:56,360 --> 00:21:59,360 we sometimes can create superior protein crystals in weightlessness 351 00:21:59,360 --> 00:22:02,360 that can help researchers design new drugs. 352 00:22:02,360 --> 00:22:04,360 Eliminating buoyancy-induced convection 353 00:22:04,360 --> 00:22:05,360 can also help us understand 354 00:22:05,360 --> 00:22:07,360 how to make better semiconductors here on Earth, 355 00:22:07,360 --> 00:22:09,360 like the ones used in your computer. 356 00:22:09,360 --> 00:22:12,360 We take a lesson from computer chip manufacturers 357 00:22:12,360 --> 00:22:14,360 who use light to make the circuit patterns. 358 00:22:14,360 --> 00:22:16,360 Microgravity research shows us 359 00:22:16,360 --> 00:22:18,360 that we can create patterns on fluids 360 00:22:18,360 --> 00:22:20,360 which would not be allowed on Earth, 361 00:22:20,360 --> 00:22:23,360 where buoyancy convection mixes up the patterns due to gravity. 362 00:22:23,360 --> 00:22:26,360 My students and I are studying how forces between molecules 363 00:22:26,360 --> 00:22:29,360 in fluids that mix can cause convection. 364 00:22:29,360 --> 00:22:31,360 We use light as an initiating agent 365 00:22:31,360 --> 00:22:33,360 to make the monomer turn into the polymer. 366 00:22:33,360 --> 00:22:36,360 By exposing the monomer to light with a specific pattern, 367 00:22:36,360 --> 00:22:39,360 we hope to observe how the monomer and polymer molecules 368 00:22:39,360 --> 00:22:40,360 pull on each other. 369 00:22:40,360 --> 00:22:42,360 For many minutes, we predict that the two fluids 370 00:22:42,360 --> 00:22:44,360 will act like oil on water. 371 00:22:44,360 --> 00:22:47,360 But in the long run, the molecules will diffuse into each other 372 00:22:47,360 --> 00:22:48,360 and make a single fluid. 373 00:22:48,360 --> 00:22:50,360 Why can't we do the experiment in the lab? 374 00:22:50,360 --> 00:22:53,360 Because buoyancy-driven convection will smear everything out, 375 00:22:53,360 --> 00:22:56,360 so there really is no way on Earth to do the experiment. 376 00:22:56,360 --> 00:22:59,360 We also study a process called frontal polymerization, 377 00:22:59,360 --> 00:23:02,360 in which plastics and foams can be made with a chemical reaction 378 00:23:02,360 --> 00:23:05,360 that spreads out like a liquid flame. 379 00:23:05,360 --> 00:23:08,360 Gases can be released by the hot reaction that makes bubbles, 380 00:23:08,360 --> 00:23:09,360 which can form the foam. 381 00:23:09,360 --> 00:23:12,360 Of course, bubbles float in a liquid because of gravity. 382 00:23:12,360 --> 00:23:14,360 But without the buoyant force, 383 00:23:14,360 --> 00:23:17,360 bubbles can become larger in a microgravity environment. 384 00:23:17,360 --> 00:23:19,360 How do you use math in your work? 385 00:23:19,360 --> 00:23:21,360 Math is essential to our work. 386 00:23:21,360 --> 00:23:23,360 For example, in order to predict 387 00:23:23,360 --> 00:23:25,360 how gravity will cause convection in our systems, 388 00:23:25,360 --> 00:23:28,360 we need to prepare graphs of the density of our materials 389 00:23:28,360 --> 00:23:30,360 as a function of temperature. 390 00:23:30,360 --> 00:23:33,360 We use a special instrument called a densitometer. 391 00:23:33,360 --> 00:23:35,360 But we have to know how to use the math 392 00:23:35,360 --> 00:23:37,360 to make sense of what it tells us. 393 00:23:37,360 --> 00:23:39,360 Let's look at some of the data from my lab. 394 00:23:39,360 --> 00:23:41,360 Here we have plotted the densities of the monomer 395 00:23:41,360 --> 00:23:43,360 and the polymer on the y-axis 396 00:23:43,360 --> 00:23:45,360 and the temperature on the x-axis. 397 00:23:45,360 --> 00:23:47,360 First, notice that the density of the polymer 398 00:23:47,360 --> 00:23:49,360 is higher than the monomer. 399 00:23:49,360 --> 00:23:52,360 Next, we can draw straight lines through the points. 400 00:23:52,360 --> 00:23:54,360 The slope of each line is the ratio 401 00:23:54,360 --> 00:23:57,360 of the change in density to the change in temperature. 402 00:23:57,360 --> 00:24:00,360 The density of the polymer decreases 403 00:24:00,360 --> 00:24:03,360 0.03 grams per cubic centimeters 404 00:24:03,360 --> 00:24:07,360 for a 50-degree centigrade increase in temperature. 405 00:24:07,360 --> 00:24:09,360 The density of the monomer also decreases, 406 00:24:09,360 --> 00:24:12,360 but it decreases 0.04 grams per cubic centimeter 407 00:24:12,360 --> 00:24:14,360 for the same temperature change. 408 00:24:14,360 --> 00:24:17,360 Remember that we said buoyancy-driven convection happens 409 00:24:17,360 --> 00:24:19,360 because of differences in density 410 00:24:19,360 --> 00:24:22,360 and that the less dense liquids will float to the top. 411 00:24:22,360 --> 00:24:24,360 The information from this graph 412 00:24:24,360 --> 00:24:26,360 tells us how the density changes 413 00:24:26,360 --> 00:24:28,360 when we heat the monomer and polymer. 414 00:24:28,360 --> 00:24:30,360 And so we can predict how much buoyancy-driven convection 415 00:24:30,360 --> 00:24:33,360 will occur during experiments on Earth. 416 00:24:33,360 --> 00:24:35,360 The graph also tells us 417 00:24:35,360 --> 00:24:37,360 how the volume changes as we heat the liquids, 418 00:24:37,360 --> 00:24:39,360 essential information for designing our experiment 419 00:24:39,360 --> 00:24:41,360 on the International Space Station. 420 00:24:41,360 --> 00:24:44,360 As we go farther and farther from Earth into space, 421 00:24:44,360 --> 00:24:46,360 we're going to be required eventually 422 00:24:46,360 --> 00:24:48,360 to make our own materials in space. 423 00:24:48,360 --> 00:24:50,360 Foams are just one of the things we need to look at. 424 00:24:50,360 --> 00:24:52,360 Gaining an understanding of the opportunities 425 00:24:52,360 --> 00:24:54,360 in microgravity research today 426 00:24:54,360 --> 00:24:56,360 will be valuable knowledge for you, 427 00:24:56,360 --> 00:24:58,360 young researchers of tomorrow, 428 00:24:58,360 --> 00:25:01,360 when we are ready for our first manned flight to Mars. 429 00:25:02,360 --> 00:25:04,360 All right, guys. 430 00:25:04,360 --> 00:25:06,360 It's now time for a cue card review. 431 00:25:06,360 --> 00:25:08,360 What is buoyancy-induced convection? 432 00:25:08,360 --> 00:25:11,360 What is the relationship between density and volume? 433 00:25:11,360 --> 00:25:15,360 What is the trend in the density-versus-temperature graph? 434 00:25:15,360 --> 00:25:17,360 Okay, did you get all that? 435 00:25:17,360 --> 00:25:20,360 Let's go visit Dan Giroux in his web domain. 436 00:25:25,360 --> 00:25:28,360 Hi, and welcome to my domain. 437 00:25:29,360 --> 00:25:32,360 NASA Connect has created a really cool web activity 438 00:25:32,360 --> 00:25:34,360 to help you understand apparent weight 439 00:25:34,360 --> 00:25:37,360 and to see how astronauts in outer space feel weightless. 440 00:25:37,360 --> 00:25:39,360 We also have a second activity 441 00:25:39,360 --> 00:25:42,360 to help you make an important elevator design decision. 442 00:25:42,360 --> 00:25:45,360 First, be sure you have the Squeak plug-in. 443 00:25:45,360 --> 00:25:49,360 It can be downloaded at www.squeakland.org. 444 00:25:49,360 --> 00:25:51,360 Free easy installation. 445 00:25:51,360 --> 00:25:53,360 Once you have the Squeak plug-in installed, 446 00:25:53,360 --> 00:25:56,360 you can access the activity at the NASA Connect website 447 00:25:56,360 --> 00:25:58,360 under Dan's domain. 448 00:25:58,360 --> 00:26:01,360 This activity is designed for use by students, teachers, 449 00:26:01,360 --> 00:26:03,360 and parents in the school or home setting. 450 00:26:03,360 --> 00:26:06,360 Now, you're ready to start the activity. 451 00:26:06,360 --> 00:26:10,360 On this site, Norbert and Zot are waiting in an elevator 452 00:26:10,360 --> 00:26:12,360 for you to investigate what happens 453 00:26:12,360 --> 00:26:14,360 when you accelerate the elevator. 454 00:26:14,360 --> 00:26:16,360 If you're the hands-on type 455 00:26:16,360 --> 00:26:18,360 and want to try it out on your own first, 456 00:26:18,360 --> 00:26:21,360 read the brief directions along the left side of the screen 457 00:26:21,360 --> 00:26:24,360 and start by trying to make Norbert and Zot weightless. 458 00:26:24,360 --> 00:26:27,360 Then you should read the book on the right side of the screen 459 00:26:27,360 --> 00:26:30,360 for important definitions, brief interactivities, 460 00:26:30,360 --> 00:26:32,360 explorations you should do, 461 00:26:32,360 --> 00:26:34,360 and challenges you should consider. 462 00:26:34,360 --> 00:26:36,360 If you want more directions before you start, 463 00:26:36,360 --> 00:26:39,360 begin by reading the book, starting with the first page, 464 00:26:39,360 --> 00:26:43,360 and click the little right arrow at the top center to go on. 465 00:26:43,360 --> 00:26:45,360 To help you get a head start, 466 00:26:45,360 --> 00:26:48,360 velocity is the distance traveled divided by the time it takes. 467 00:26:48,360 --> 00:26:51,360 If the elevator moves Norbert and Zot downward, 468 00:26:51,360 --> 00:26:54,360 we will say their velocity is a positive number. 469 00:26:54,360 --> 00:26:56,360 To accelerate is to change the velocity. 470 00:26:56,360 --> 00:26:59,360 If you increase the velocity in the downward direction, 471 00:26:59,360 --> 00:27:02,360 we will say the acceleration is a positive number. 472 00:27:02,360 --> 00:27:05,360 Then, if you increase the velocity in an upward direction, 473 00:27:05,360 --> 00:27:08,360 the acceleration will be a negative number. 474 00:27:08,360 --> 00:27:11,360 Positive and negative numbers are essential to describe motion. 475 00:27:11,360 --> 00:27:14,360 Have fun and explore. 476 00:27:17,360 --> 00:27:20,360 Well, guys, that wraps up another episode of NASA Connect. 477 00:27:20,360 --> 00:27:23,360 Got a comment, question, or suggestion? 478 00:27:23,360 --> 00:27:27,360 Then email us at connect at lark dot nasa dot gov. 479 00:27:27,360 --> 00:27:31,360 Or pick up a pen and write us at NASA Connect, 480 00:27:31,360 --> 00:27:33,360 NASA Center for Distance Learning, 481 00:27:33,360 --> 00:27:35,360 NASA Langley Research Center, 482 00:27:35,360 --> 00:27:39,360 Mail Stop 400, Hampton, Virginia, 23681. 483 00:27:39,360 --> 00:27:42,360 Teachers, if you would like a videotape of this program 484 00:27:42,360 --> 00:27:44,360 and the accompanying educator's guide, 485 00:27:44,360 --> 00:27:46,360 check out the NASA Connect website. 486 00:27:47,360 --> 00:27:53,360 So, until next time, stay connected to math, science, technology, and NASA. 487 00:27:53,360 --> 00:27:55,360 See you then. 488 00:28:00,360 --> 00:28:02,360 The gravity of the moon, right? 489 00:28:02,360 --> 00:28:03,360 The gravity of the moon. 490 00:28:03,360 --> 00:28:05,360 The young researchers of tomorrow. 491 00:28:07,360 --> 00:28:09,360 Blah, blah, blah, blah. 492 00:28:10,360 --> 00:28:11,360 What? 493 00:28:11,360 --> 00:28:12,360 That's it, that's it. 494 00:28:13,360 --> 00:28:14,360 Very. 495 00:28:14,360 --> 00:28:15,360 Very. 496 00:28:17,360 --> 00:28:19,360 Let me look at it one more time. 497 00:28:19,360 --> 00:28:21,360 Dr. Olsen! Jennifer! 498 00:28:26,360 --> 00:28:29,360 Captioning funded by the NAC Foundation of America.