1 00:00:00,000 --> 00:00:03,500 Hi, kids. Welcome to your astronaut training program. 2 00:00:03,500 --> 00:00:07,500 Astronaut training? I thought we were here to ride roller coasters. 3 00:00:07,500 --> 00:00:12,500 That's exactly right. I want you to be able to experience the thrill of space travel. 4 00:00:12,500 --> 00:00:16,500 And the best way to do it here on Earth is on a roller coaster. 5 00:00:16,500 --> 00:00:19,500 What do roller coasters have to do with space travel? 6 00:00:19,500 --> 00:00:23,500 I know that roller coasters go fast, but not nearly as fast as rocket ships. 7 00:00:23,500 --> 00:00:28,500 That's right. But it turns out the thrill of space travel doesn't come from going at high speeds. 8 00:00:28,500 --> 00:00:30,000 It comes from accelerations. 9 00:00:30,000 --> 00:00:34,000 We've learned before that acceleration is a change in speed or direction. 10 00:00:34,000 --> 00:00:39,000 Precisely. The important point is that forces are needed to cause accelerations. 11 00:00:39,000 --> 00:00:41,000 Remember the law of inertia? 12 00:00:41,000 --> 00:00:47,000 I remember. It states that objects at rest stay at rest and objects in motion remain in motion. 13 00:00:47,000 --> 00:00:50,000 Very good. Let's get this bowling ball rolling. 14 00:00:59,000 --> 00:01:02,000 What if I hit it from the side? 15 00:01:02,000 --> 00:01:06,000 I would guess that it wouldn't change speed. I'm not sure what it would do. 16 00:01:06,000 --> 00:01:08,000 Let's try it. 17 00:01:08,000 --> 00:01:11,000 It changed direction without changing speed. 18 00:01:11,000 --> 00:01:15,000 The same thing happens to the roller coaster car at the bottom of the hill. 19 00:01:15,000 --> 00:01:18,000 It has inertia and wants to maintain its downward motion, 20 00:01:18,000 --> 00:01:23,000 but the track pushes the car perpendicular to its motion and sends it uphill. 21 00:01:23,000 --> 00:01:25,000 What does the push of the track do to the passengers? 22 00:01:25,500 --> 00:01:27,500 It makes them feel heavy. 23 00:01:27,500 --> 00:01:31,500 The faster the coaster is going or the tighter the turn, the heavier they will feel. 24 00:01:31,500 --> 00:01:34,500 How heavy will you feel on a roller coaster? 25 00:01:34,500 --> 00:01:39,500 Here on the Alpengeist, you feel about four times heavier than normal at the bottom of a couple of the hills. 26 00:01:39,500 --> 00:01:45,500 It turns out the space shuttle astronauts only feel three times heavier than normal when the shuttle is taking off. 27 00:01:45,500 --> 00:01:48,500 So you were right. We are going to be in training to be astronauts. 28 00:01:48,500 --> 00:01:53,500 The difference is on the Alpengeist you feel heavy for only a few seconds at a time, 29 00:01:54,000 --> 00:01:57,000 but on the space shuttle you feel heavy for about eight minutes. 30 00:01:57,000 --> 00:02:02,000 Don't astronauts also feel weightless? Will we be able to experience that on the Alpengeist? 31 00:02:02,000 --> 00:02:03,000 You bet. 32 00:02:03,000 --> 00:02:09,000 Once the engines are cut off after about eight minutes and the shuttle goes into orbit, the astronauts are weightless. 33 00:02:09,000 --> 00:02:13,000 Weightlessness is experienced with only gravity acts on an object. 34 00:02:13,000 --> 00:02:14,000 It's called free fall. 35 00:02:14,000 --> 00:02:15,000 Let me show you. 36 00:02:15,000 --> 00:02:20,000 When I jump off this bin, the points of my hat will float as if they're weightless 37 00:02:20,500 --> 00:02:23,500 and this spring hanging from my hand will collapse. 38 00:02:25,500 --> 00:02:29,500 Wow, Dr. D. What you go through to show us how science works. 39 00:02:29,500 --> 00:02:32,500 So where on the coaster ride are we going to be falling? 40 00:02:32,500 --> 00:02:36,500 Free fall is not always down. Remember, it's when only gravity acts. 41 00:02:36,500 --> 00:02:40,500 So when I throw this koosh ball, watch which path it follows. 42 00:02:42,500 --> 00:02:46,500 I've seen that before with the Vomit Comet when we were learning about habitats. 43 00:02:46,500 --> 00:02:48,500 I think it's called a parabola. 44 00:02:49,000 --> 00:02:53,000 Very good. The coaster goes over a parabolic hill and twists at the same time. 45 00:02:53,000 --> 00:02:55,000 For a few seconds, you're weightless. 46 00:02:55,000 --> 00:02:57,000 This is going to be exciting. 47 00:02:57,000 --> 00:02:58,000 Can we go on the ride now? 48 00:02:58,000 --> 00:03:03,000 One more thing. You can tell how heavy you feel by watching this accelerometer. 49 00:03:03,000 --> 00:03:09,000 When you feel three times as heavy as normal, this mass will be pulled onto this point right here. 50 00:03:09,000 --> 00:03:15,000 Einstein told us that being heavy on a roller coaster and being heavy on a big planet are the same thing. 51 00:03:15,500 --> 00:03:19,500 I guess we're preparing for both space travel and visiting an alien planet. 52 00:03:19,500 --> 00:03:22,500 Let's go on the ride. I'm ready to be an astronaut. 53 00:03:22,500 --> 00:03:26,500 Okay, it's good to experience the physics and not just talk about it. 54 00:03:26,500 --> 00:03:31,500 Don't forget to watch the accelerometer and try to figure out where you are when you feel the heaviest. 55 00:03:31,500 --> 00:03:33,500 Come on, let's go. 56 00:03:33,500 --> 00:03:35,500 Here we go. 57 00:03:45,500 --> 00:03:49,500 That was so great. I felt heavy at the bottom of the hills. 58 00:03:49,500 --> 00:03:54,500 I noticed the accelerometer read more than three a number of times, but I lost count. 59 00:03:54,500 --> 00:03:56,500 I noticed I felt weightless a few times. 60 00:03:56,500 --> 00:04:00,500 I had no idea where I was on the ride, but it was exciting. 61 00:04:00,500 --> 00:04:04,500 Thanks, Dr. D. Now we have some practical space travel experience. 62 00:04:04,500 --> 00:04:06,500 You're welcome. You'll be great astronauts. 63 00:04:06,500 --> 00:04:08,500 Oh, I've got to run. See you later. 64 00:04:08,500 --> 00:04:10,500 Bye, Dr. D. Thanks.