1 00:00:00,000 --> 00:00:04,400 Be sure to look for the answers to the following questions. 2 00:00:04,400 --> 00:00:05,400 What is solar wind? 3 00:00:05,400 --> 00:00:06,400 What does voltage measure? 4 00:00:06,400 --> 00:00:07,400 Name the layers of the atmosphere. 5 00:00:07,400 --> 00:00:08,400 Describe a convection cell on the sun. 6 00:00:08,400 --> 00:00:21,640 When you see this icon, the answer is near. 7 00:00:21,640 --> 00:00:23,880 What about a nice bag of beef jerky? 8 00:00:23,880 --> 00:00:28,000 Don't you think after a long day of hiking and geocaching, you might want some beef jerky 9 00:00:28,000 --> 00:00:29,440 or something of substance? 10 00:00:29,440 --> 00:00:30,440 Sorry, Jacob. 11 00:00:30,440 --> 00:00:31,440 Nothing perishable. 12 00:00:31,440 --> 00:00:35,960 We need to put things into our cache that are fun and interesting as treasure, not a 13 00:00:35,960 --> 00:00:36,960 meal. 14 00:00:36,960 --> 00:00:38,800 Well, I'm running out of ideas. 15 00:00:38,800 --> 00:00:40,000 What do you have so far? 16 00:00:40,000 --> 00:00:44,040 I had lots of food items. 17 00:00:44,040 --> 00:00:49,680 Signal flares might be hazardous in the forest. 18 00:00:49,680 --> 00:00:50,680 Cache or a gift certificate? 19 00:00:50,680 --> 00:00:53,760 Why don't we just put travel bugs in our caches? 20 00:00:53,760 --> 00:00:55,440 Hi, RJ. 21 00:00:55,440 --> 00:00:57,360 What are travel bugs? 22 00:00:57,360 --> 00:00:59,320 They sure don't sound like treasure. 23 00:00:59,320 --> 00:01:02,160 My dad got me this one on the internet. 24 00:01:02,160 --> 00:01:04,480 It doesn't look like a bug. 25 00:01:04,480 --> 00:01:05,880 It's not a real bug. 26 00:01:05,880 --> 00:01:08,720 Each travel bug has its own unique tracking number. 27 00:01:08,720 --> 00:01:12,600 So when someone finds our cache, they take out the travel bug and place it into a different 28 00:01:12,600 --> 00:01:13,600 location. 29 00:01:13,600 --> 00:01:17,720 Then they look up on the internet the travel bug tracking number and type in the new location 30 00:01:17,720 --> 00:01:19,240 of the cache that they placed it in. 31 00:01:19,240 --> 00:01:23,320 So your travel bug could travel to geocaches all around town? 32 00:01:23,320 --> 00:01:25,640 Actually, it can travel the world. 33 00:01:25,640 --> 00:01:26,640 How would that work? 34 00:01:26,640 --> 00:01:31,120 Let's say we place a travel bug in our cache and then someone from New York is geocaching 35 00:01:31,120 --> 00:01:32,120 in our area. 36 00:01:32,120 --> 00:01:35,880 They take the bug back to New York and place it in a cache in their city. 37 00:01:35,880 --> 00:01:40,320 Someone from London visits New York to geocache and then they take it with them back to London. 38 00:01:40,320 --> 00:01:41,780 What a cool idea. 39 00:01:41,780 --> 00:01:43,640 We have to get some travel bugs. 40 00:01:43,640 --> 00:01:45,740 We have one, but we can get some more. 41 00:01:45,740 --> 00:01:47,800 Our travel bugs could see the world. 42 00:01:47,800 --> 00:01:48,800 How cool is that? 43 00:01:48,800 --> 00:01:49,800 Wait a minute. 44 00:01:49,800 --> 00:01:51,560 We're getting ahead of ourselves. 45 00:01:51,560 --> 00:01:55,400 I know working on our caches is part of the assignment, but we still haven't solved our 46 00:01:55,400 --> 00:01:56,400 problem. 47 00:01:57,160 --> 00:02:00,880 I was reading Tony's report on electricity and he said we need to learn more about magnetism. 48 00:02:00,880 --> 00:02:04,160 I think Ula and Neena are meeting with Dr. D again. 49 00:02:04,160 --> 00:02:06,400 Hopefully we should get their report soon. 50 00:02:06,400 --> 00:02:13,960 For great ideas on creating reports, visit the Treehouse and the NASA Sci-Files website. 51 00:02:13,960 --> 00:02:17,440 I'm really looking forward to the Northern Lights Festival tonight and hopefully seeing 52 00:02:17,440 --> 00:02:19,840 some auroras with the kids club members. 53 00:02:19,840 --> 00:02:24,160 Andanus is the perfect spot for viewing auroras because it is located directly under the auroral 54 00:02:24,160 --> 00:02:25,160 oval. 55 00:02:25,160 --> 00:02:29,520 Of course, Neena and Ula are also investigating magnetism for the Treehouse detectives. 56 00:02:29,520 --> 00:02:31,760 This is a good place to start. 57 00:02:31,760 --> 00:02:34,480 We know that magnets have a North Pole and a South Pole. 58 00:02:34,480 --> 00:02:38,640 And the two North Poles repel and the North and the South Pole attract each other. 59 00:02:38,640 --> 00:02:39,640 Very good. 60 00:02:39,640 --> 00:02:44,240 Let's demonstrate that by having you push light poles of these two magnets together. 61 00:02:44,240 --> 00:02:51,080 Oi, they're really strong. 62 00:02:51,080 --> 00:02:58,080 Let's take a look at the magnetic field of this permanent bar magnet. 63 00:02:58,080 --> 00:03:05,240 That's impressive. 64 00:03:05,240 --> 00:03:09,320 Notice how the South Pole, or white part of this compass needle, points to the North Pole 65 00:03:09,320 --> 00:03:10,320 of the bar magnet. 66 00:03:10,320 --> 00:03:14,560 So if a compass always points to where the Earth's North Pole, that must mean that the 67 00:03:14,560 --> 00:03:17,040 Earth is a big magnet with a magnetic pole up north. 68 00:03:17,040 --> 00:03:18,040 You're right. 69 00:03:18,040 --> 00:03:21,000 This magnetic field looks very similar to the field of this bar magnet. 70 00:03:21,000 --> 00:03:24,760 I heard that the Chinese used a lodestone to produce their first compass. 71 00:03:24,760 --> 00:03:26,440 Historians think so. 72 00:03:26,440 --> 00:03:29,080 Here is a piece of lodestone, a naturally magnetic rock. 73 00:03:29,080 --> 00:03:33,480 If I float it on this phone, it will point north. 74 00:03:33,480 --> 00:03:36,120 Doesn't magnetism have something to do with electricity? 75 00:03:36,120 --> 00:03:37,520 Yes it does. 76 00:03:37,520 --> 00:03:39,960 Magnetic fields are produced by moving charges. 77 00:03:39,960 --> 00:03:44,000 Let's make an electromagnet by having an electric current flow through this wire which is wrapped 78 00:03:44,000 --> 00:03:49,000 around an iron bar. 79 00:03:49,000 --> 00:03:50,720 This field looks just like the bar magnets. 80 00:03:50,720 --> 00:03:57,640 Except when I turn off the current of an electromagnet, the magnetic field disappears. 81 00:03:57,640 --> 00:04:01,480 So is the Earth like a giant electromagnet or like a permanent magnet? 82 00:04:01,480 --> 00:04:06,480 Well, the Earth has an outer core made of molten iron that is constantly in motion. 83 00:04:06,480 --> 00:04:11,600 A process called the dynamo effect creates huge currents of electricity in the iron which 84 00:04:11,960 --> 00:04:14,000 produces a giant electromagnet. 85 00:04:14,000 --> 00:04:17,840 In like manner, the Earth's magnetic field deflects the protons and electrons of the 86 00:04:17,840 --> 00:04:22,840 solar wind which the Sun is throwing at the Earth at hundreds of kilometers per second. 87 00:04:22,840 --> 00:04:25,000 Ah, I get it. 88 00:04:25,000 --> 00:04:29,320 Didn't a Norwegian scientist named Christian Birkland investigate the solar winds and auroras? 89 00:04:29,320 --> 00:04:30,320 That's right. 90 00:04:30,320 --> 00:04:34,080 He used a magnetized sphere called a torella to represent the Earth and he fired an electron 91 00:04:34,080 --> 00:04:36,360 beam at it to simulate the solar wind. 92 00:04:36,360 --> 00:04:37,360 What did he discover? 93 00:04:37,520 --> 00:04:41,720 He found that the electron beam did cause the gases in the chamber to glow like an aurora 94 00:04:41,720 --> 00:04:45,520 and the magnetic field guided the electrons like beads in a string to the poles of the 95 00:04:45,520 --> 00:04:46,520 torella. 96 00:04:46,520 --> 00:04:49,160 And we know that auroras occur on Earth near its poles. 97 00:04:49,160 --> 00:04:50,160 Very good. 98 00:04:50,160 --> 00:04:53,600 Here is an example of how high energy electrons can cause a gas to glow. 99 00:04:53,600 --> 00:04:59,480 This is a tube of helium gas hooked up to a high voltage power supply. 100 00:04:59,480 --> 00:05:01,560 The tube is glowing pink. 101 00:05:01,560 --> 00:05:04,400 Each gas gives off its own special color. 102 00:05:04,400 --> 00:05:06,760 Here is neon gas which looks orange. 103 00:05:06,760 --> 00:05:08,680 Just like the lights at restaurants. 104 00:05:08,680 --> 00:05:10,040 That's right. 105 00:05:10,040 --> 00:05:14,600 Auroras produce greens, blues and reds when electrons collide with oxygen and nitrogen 106 00:05:14,600 --> 00:05:17,920 atoms hundreds of kilometers above the Earth's surface. 107 00:05:17,920 --> 00:05:19,560 Auroras certainly don't look that high. 108 00:05:19,560 --> 00:05:22,360 Dr. Deek, wasn't there a problem with Birkland's theory? 109 00:05:22,360 --> 00:05:26,240 Yes, he had the misconception that it was electrons coming directly from the Sun that 110 00:05:26,240 --> 00:05:27,240 caused the aurora. 111 00:05:27,240 --> 00:05:28,800 Well, where do they come from? 112 00:05:28,800 --> 00:05:30,440 They do come in part from the Sun. 113 00:05:30,440 --> 00:05:34,880 The solar wind compresses the magnetic field on the day side of the Earth and stretches 114 00:05:34,880 --> 00:05:38,880 it into a long tail called the magnetotail on the night side. 115 00:05:38,880 --> 00:05:42,400 Electrons from the solar wind flow around the day side and into the magnetosphere at 116 00:05:42,400 --> 00:05:43,400 the tail. 117 00:05:43,400 --> 00:05:44,400 Then what happens? 118 00:05:44,400 --> 00:05:48,480 The electrons in the magnetotail are then pulled back down toward the poles at increasingly 119 00:05:48,480 --> 00:05:50,360 high speeds by electric forces. 120 00:05:50,360 --> 00:05:52,520 These are called Birkland currents. 121 00:05:52,520 --> 00:05:56,880 And when they collide with the gases in the atmosphere near the poles, we have an aurora. 122 00:05:56,880 --> 00:05:57,880 Exactly. 123 00:05:57,880 --> 00:06:01,960 But to really understand auroras, you must first learn more about activity on the Sun 124 00:06:01,960 --> 00:06:03,480 like sunspots and flares. 125 00:06:03,480 --> 00:06:04,480 Thanks, Dr. Deek. 126 00:06:04,920 --> 00:06:07,640 Let's get our report on magnetism ready for the Trias detectives. 127 00:06:07,640 --> 00:06:09,640 Maybe they can help us investigate the Sun. 128 00:06:15,640 --> 00:06:17,880 Okay, let's fire up the computer. 129 00:06:17,880 --> 00:06:22,320 I'm ready to talk magnetism with our friends at the Andenes Barnard School in Norway. 130 00:06:22,320 --> 00:06:24,320 It's not every day we have a transatlantic experiment. 131 00:06:24,320 --> 00:06:27,800 I would love to visit Norway and see the culture close up. 132 00:06:27,800 --> 00:06:29,640 Well, how about the next best thing? 133 00:06:29,640 --> 00:06:32,520 We're ready to talk to the NASA Sci-Files Kids Club members in Andenes. 134 00:06:32,520 --> 00:06:33,520 Perfect. 135 00:06:33,560 --> 00:06:36,560 They should be ready just about now. 136 00:06:36,560 --> 00:06:39,760 Hi, I'm Jacob here with Bianca. 137 00:06:39,760 --> 00:06:41,760 We understand you're doing an experiment on magnetism. 138 00:06:41,760 --> 00:06:42,760 Hi, I'm Ingrid. 139 00:06:42,760 --> 00:06:43,760 And I'm Alexander. 140 00:06:43,760 --> 00:06:44,760 Hi. 141 00:06:44,760 --> 00:06:48,960 Dr. Deek told us that you're working on an electromagnet experiment. 142 00:06:48,960 --> 00:06:50,360 Can you tell us about it? 143 00:06:50,360 --> 00:06:51,360 Sure. 144 00:06:51,360 --> 00:06:56,280 Our electromagnet is a wire wrapped around an iron nail attached to a battery. 145 00:06:56,280 --> 00:07:01,920 We wanted to find out how the strength of the electromagnet changes when we increase 146 00:07:01,920 --> 00:07:02,920 the voltage. 147 00:07:03,320 --> 00:07:06,360 And we increase the voltage by using more batteries. 148 00:07:06,360 --> 00:07:10,720 We learned in science class that a battery is like an electrical pump that pushes electrons 149 00:07:10,720 --> 00:07:11,960 through a circuit. 150 00:07:11,960 --> 00:07:14,040 The voltage measures the push. 151 00:07:14,040 --> 00:07:16,760 And the flow of electrons through the wire is called a current. 152 00:07:16,760 --> 00:07:17,760 We learned that too. 153 00:07:17,760 --> 00:07:23,040 We also learned that as the voltage is increased, the current in the wire will increase. 154 00:07:23,040 --> 00:07:28,680 So we hypothesized that if we increase the voltage and get more current, then the strength 155 00:07:28,680 --> 00:07:31,560 of the electromagnet will also increase. 156 00:07:31,600 --> 00:07:33,240 Sounds like excellent reasoning. 157 00:07:33,240 --> 00:07:37,400 We began by wrapping wire around the nail 300 times. 158 00:07:37,400 --> 00:07:41,200 Next we placed a 1.5 volt battery in the battery pack. 159 00:07:41,200 --> 00:07:45,440 We then connected one end of the wire to the positive battery terminal. 160 00:07:45,440 --> 00:07:51,920 And to complete the circuit, we connected the other end to the negative terminal. 161 00:07:51,920 --> 00:07:56,320 You won't get any current or flow of electrons unless you have a complete circuit. 162 00:07:56,320 --> 00:07:57,320 That's right. 163 00:07:57,320 --> 00:08:01,480 And the current in the wire then causes the nail to become a magnet. 164 00:08:01,480 --> 00:08:06,760 To test the strength of the magnet, we placed it in a cup of paperclips. 165 00:08:06,760 --> 00:08:10,320 I would think that the stronger the magnet, the more paperclips it would pick up. 166 00:08:10,320 --> 00:08:11,320 We agree. 167 00:08:11,320 --> 00:08:14,840 In our first trial, we picked up six paperclips. 168 00:08:14,840 --> 00:08:19,080 We know in an experiment it is important to do multiple trials and then find the average. 169 00:08:19,080 --> 00:08:20,080 What was your average? 170 00:08:20,080 --> 00:08:24,580 The class average was eight paperclips with 1.5 volt battery. 171 00:08:24,580 --> 00:08:31,500 To continue to test our hypothesis, we added another 1.5 volt battery, increasing the voltage 172 00:08:31,500 --> 00:08:33,340 to three volts. 173 00:08:33,340 --> 00:08:36,500 The average was 14 paperclips with two batteries. 174 00:08:36,500 --> 00:08:37,500 Wow! 175 00:08:37,500 --> 00:08:40,980 You doubled the voltage and almost doubled the number of paperclips. 176 00:08:40,980 --> 00:08:43,620 We continue by adding a third battery. 177 00:08:43,620 --> 00:08:47,900 With 4.5 volts, we averaged 21 paperclips. 178 00:08:47,940 --> 00:08:54,740 Four batteries, or six volts, picked up an average of 30 paperclips. 179 00:08:54,740 --> 00:08:55,740 Congratulations! 180 00:08:55,740 --> 00:08:57,740 It looks like you've proved your hypothesis. 181 00:08:57,740 --> 00:08:58,740 That's right. 182 00:08:58,740 --> 00:09:01,460 We graphed the results as well. 183 00:09:01,460 --> 00:09:07,420 A graph clearly shows that the strength of the magnet increases as the voltage increases. 184 00:09:07,420 --> 00:09:14,140 Our teacher, Ulla, also told us that the Earth's magnetic field is very similar to our electromagnet, 185 00:09:14,140 --> 00:09:18,660 except the current in the Earth is a billion times the current in our circuit. 186 00:09:18,660 --> 00:09:19,660 That's incredible! 187 00:09:19,660 --> 00:09:24,620 I was wondering, does the number of times you wrap the wire around the nail make a difference? 188 00:09:24,620 --> 00:09:28,140 We think so, but that is what we're going to test next. 189 00:09:28,140 --> 00:09:29,140 Great! 190 00:09:29,140 --> 00:09:30,140 Be sure to send us your results. 191 00:09:30,140 --> 00:09:31,140 We will. 192 00:09:31,140 --> 00:09:32,140 Goodbye. 193 00:09:32,140 --> 00:09:35,140 From Andenes Børneskole, Norway. 194 00:09:38,140 --> 00:09:40,140 I can't believe all the cool experiments we've seen. 195 00:09:40,140 --> 00:09:45,140 Anthony, Dr. Bagnall, Dr. Dean, the Kids Club members, and now the Kids Club in Norway. 196 00:09:45,140 --> 00:09:50,140 Clearly there's a connection between electricity and magnetism, but I'm not sure how. 197 00:09:50,140 --> 00:09:53,140 I'm still sorting through Ulla and Nina's report on auroras. 198 00:09:53,140 --> 00:09:58,140 Dr. D also said that before we can fully understand auroras, we need to learn more about the Sun. 199 00:09:58,140 --> 00:10:00,140 I completely forgot about the Sun. 200 00:10:00,140 --> 00:10:02,140 How are we going to learn more about the Sun? 201 00:10:02,140 --> 00:10:03,140 Don't worry. 202 00:10:03,140 --> 00:10:07,140 I've done some research on the Internet, and NASA does lots of research on the Sun. 203 00:10:07,140 --> 00:10:08,140 Of course! 204 00:10:08,140 --> 00:10:09,140 The answer is NASA. 205 00:10:09,140 --> 00:10:10,140 Let's go. 206 00:10:10,140 --> 00:10:11,140 Slow down. 207 00:10:11,140 --> 00:10:17,140 Ulla and Nina also reported a teleconference that they had with North Shore Christian Academy in Everett, Washington. 208 00:10:17,140 --> 00:10:19,140 Oh, I see. 209 00:10:19,140 --> 00:10:20,140 I think. 210 00:10:20,140 --> 00:10:25,140 Before learning about the Sun, they talked with the students at North Shore about the layers of the Earth's atmosphere. 211 00:10:25,140 --> 00:10:28,140 The layers of the Earth's atmosphere. 212 00:10:28,140 --> 00:10:35,140 You know, the troposphere, closest to the Earth, and the mesosphere, which is very cold and the air is very thin. 213 00:10:35,140 --> 00:10:39,140 And, of course, the thermosphere and ionosphere, where most of the auroras occur. 214 00:10:39,140 --> 00:10:41,140 Jacob, I'm impressed. 215 00:10:41,140 --> 00:10:44,140 I've been doing more than surfing the Web and reading reports. 216 00:10:44,140 --> 00:10:47,140 Every once in a while, you have to go old school and use books. 217 00:10:47,140 --> 00:10:50,140 Well, I'm glad you haven't forgotten such a great resource. 218 00:10:50,140 --> 00:10:52,140 But we still need to learn more about the Sun. 219 00:10:52,140 --> 00:10:53,140 Well, we're in luck. 220 00:10:53,140 --> 00:10:57,140 Catherine and RJ are meeting with Dr. Nikki Fox to learn more about the Sun. 221 00:10:57,140 --> 00:11:03,140 She's at the Johns Hopkins Applied Physics Laboratory and works with scientists at NASA Goddard Space Flight Center. 222 00:11:03,140 --> 00:11:07,140 I'm sure they'll find the Sun very illuminating. 223 00:11:07,140 --> 00:11:08,140 Very funny. 224 00:11:08,140 --> 00:11:10,140 But I can't wait to read their report.