1 00:00:00,000 --> 00:00:03,000 Be sure to look for the answers to the following questions. 2 00:00:03,000 --> 00:00:07,000 What are some other uses for a GPS? 3 00:00:07,000 --> 00:00:10,000 What star can we use to find north? 4 00:00:10,000 --> 00:00:14,000 How did the Vikings navigate without a compass or the stars? 5 00:00:14,000 --> 00:00:17,000 When you see this icon, the answer is near. 6 00:00:30,000 --> 00:00:59,000 Great, keep up the good work and keep looking. 7 00:01:00,000 --> 00:01:02,000 Hi, I'm glad you're here. 8 00:01:02,000 --> 00:01:04,000 We're close to finding our first geocache. 9 00:01:04,000 --> 00:01:06,000 You guys are quick. 10 00:01:06,000 --> 00:01:09,000 I'm still trying to figure out this whole geocaching thing. 11 00:01:09,000 --> 00:01:10,000 It's simple. 12 00:01:10,000 --> 00:01:15,000 It's like a scavenger hunt using a Global Positioning System device, or GPS. 13 00:01:15,000 --> 00:01:18,000 You create a cache, which is just a container to hold your treasure. 14 00:01:18,000 --> 00:01:22,000 Then you take it to a public park or another public area and you hide it, 15 00:01:22,000 --> 00:01:24,000 using your GPS to know its exact location. 16 00:01:24,000 --> 00:01:28,000 Because you have to post the exact coordinates on the Internet. 17 00:01:28,000 --> 00:01:32,000 Exactly, so other GPS users can find the treasure in your cache. 18 00:01:32,000 --> 00:01:33,000 They take your treasure? 19 00:01:33,000 --> 00:01:36,000 They have to replace your treasure with a new treasure so others can find it. 20 00:01:36,000 --> 00:01:37,000 That makes sense. 21 00:01:37,000 --> 00:01:41,000 Ms. Rickles told us all about geocaching when she gave us our geography assignment. 22 00:01:41,000 --> 00:01:44,000 What I can't figure out is how a GPS works. 23 00:01:44,000 --> 00:01:47,000 How does this thing know your exact location? 24 00:01:47,000 --> 00:01:50,000 And do I really want anyone to know my exact location? 25 00:01:50,000 --> 00:01:52,000 Well, you would if you were lost. 26 00:01:52,000 --> 00:01:53,000 That's true. 27 00:01:53,000 --> 00:01:56,000 I guess I need to do more research on how a GPS works. 28 00:01:56,000 --> 00:01:59,000 I know it uses satellites, but I'm not sure how. 29 00:01:59,000 --> 00:02:02,000 While you're up, do you think you could find the coordinates for some chocolate? 30 00:02:02,000 --> 00:02:04,000 It was a simple task. 31 00:02:04,000 --> 00:02:07,000 All you had to do was put batteries into the GPS. 32 00:02:07,000 --> 00:02:10,000 Batteries have nothing to do with the problem. 33 00:02:10,000 --> 00:02:11,000 It must be something... 34 00:02:11,000 --> 00:02:16,000 If the GPS doesn't work, or if it says we are somewhere we are not, then basically, we're lost. 35 00:02:19,000 --> 00:02:20,000 I can't believe it. 36 00:02:20,000 --> 00:02:23,000 Our position keeps changing, but we haven't moved. 37 00:02:23,000 --> 00:02:26,000 The GPS is giving us a lot of different coordinates. 38 00:02:26,000 --> 00:02:29,000 According to my compass, in our last coordinates... 39 00:02:29,000 --> 00:02:31,000 Let me see. 40 00:02:31,000 --> 00:02:33,000 North is over here... 41 00:02:33,000 --> 00:02:36,000 I think I better get in touch with the other treehouse detectives. 42 00:02:41,000 --> 00:02:43,000 I can't figure it out either. 43 00:02:43,000 --> 00:02:45,000 Just stay calm and keep taking good notes. 44 00:02:45,000 --> 00:02:47,000 We'll see what we can find out later. 45 00:02:47,000 --> 00:02:48,000 Over. 46 00:02:48,000 --> 00:02:49,000 That can't be good. 47 00:02:49,000 --> 00:02:51,000 No, it isn't. 48 00:02:51,000 --> 00:02:56,000 Everything was going fine, and then both teams reported having problems with their GPS. 49 00:02:56,000 --> 00:03:01,000 Well, from the sketchy radio communications, it sounds like they're receiving random coordinates. 50 00:03:01,000 --> 00:03:04,000 Yes, but they weren't even moving. 51 00:03:04,000 --> 00:03:05,000 Hmm. 52 00:03:05,000 --> 00:03:09,000 Identifying a location precisely is what geocaching is all about. 53 00:03:09,000 --> 00:03:11,000 Sounds like we need to go to the problem board. 54 00:03:11,000 --> 00:03:12,000 Good idea. 55 00:03:12,000 --> 00:03:13,000 So what do we know? 56 00:03:13,000 --> 00:03:19,000 We know that both teams are using GPS devices, and that everything was going fine until just recently. 57 00:03:19,000 --> 00:03:21,000 Looks like they're experiencing some kind of technical problems. 58 00:03:21,000 --> 00:03:22,000 Right. 59 00:03:22,000 --> 00:03:27,000 Both GPS devices began to give incorrect location coordinates at about the same time. 60 00:03:27,000 --> 00:03:32,000 We also know that a GPS uses information from satellites to give precise locations. 61 00:03:32,000 --> 00:03:34,000 So what do we need to know? 62 00:03:34,000 --> 00:03:38,000 We need to know how GPS, or Global Positioning Systems, work. 63 00:03:41,000 --> 00:03:44,000 What goes on under your hard plastic cover? 64 00:03:44,000 --> 00:03:46,000 What makes you tick? 65 00:03:46,000 --> 00:03:48,000 I don't know where we need to go. 66 00:03:48,000 --> 00:03:51,000 But someone needs to go outside and take a break. 67 00:03:52,000 --> 00:03:54,000 Did you say something? 68 00:03:54,000 --> 00:03:55,000 Yes. 69 00:03:55,000 --> 00:03:56,000 Where do we need to go? 70 00:03:56,000 --> 00:04:01,000 I'm meeting with Dr. D later this afternoon via the Internet to discuss my project on the history of navigation. 71 00:04:01,000 --> 00:04:02,000 Maybe he can help. 72 00:04:02,000 --> 00:04:03,000 Good. 73 00:04:03,000 --> 00:04:08,000 I'm meeting with Mr. Charles Cope to pick up some information about the NASA SHARP program for my brother. 74 00:04:08,000 --> 00:04:10,000 Mr. Cope is a pilot for NASA. 75 00:04:10,000 --> 00:04:12,000 Pilots use GPS. 76 00:04:12,000 --> 00:04:15,000 Maybe he can answer some of our questions about how GPS works. 77 00:04:15,000 --> 00:04:17,000 Pilot from NASA? 78 00:04:17,000 --> 00:04:18,000 I'm sure he'll be able to help. 79 00:04:18,000 --> 00:04:22,000 Don't forget to take a get-up-and-go sheet for some serious note-taking. 80 00:04:22,000 --> 00:04:27,000 Visit the NASA SciFiles website to find some cool research tools for your own investigation. 81 00:04:34,000 --> 00:04:36,000 Guys, we're making progress. 82 00:04:36,000 --> 00:04:38,000 The GPS now says we're in Virginia. 83 00:04:38,000 --> 00:04:41,000 Of course it says we're in the middle of the Chesapeake Bay. 84 00:04:41,000 --> 00:04:44,000 But we're making progress. 85 00:04:44,000 --> 00:04:46,000 Guys? 86 00:04:46,000 --> 00:04:47,000 Guys?