1 00:00:00,000 --> 00:00:06,000 Hi, our friend Jacob just broke his foot, and he is learning a little bit about what it is like to be disabled. 2 00:00:06,000 --> 00:00:10,000 Oh, that's too bad, but at least his foot will be well soon. 3 00:00:10,000 --> 00:00:15,000 He really wants to come into the treehouse, but it's not wheelchair accessible. Have you experienced that? 4 00:00:15,000 --> 00:00:21,000 Yes, a lot of places are not built to accommodate people who are in wheelchairs or have other disabilities. 5 00:00:21,000 --> 00:00:26,000 But today, public places are required by law to be accessible to everyone. 6 00:00:26,000 --> 00:00:31,000 I didn't know that there were laws that require buildings to be accessible to everyone. 7 00:00:31,000 --> 00:00:35,000 What can you do to make buildings accessible to people with disabilities? 8 00:00:35,000 --> 00:00:40,000 Well, a lot of buildings use simple machines, such as a ramp, which is an inclined plane. 9 00:00:40,000 --> 00:00:44,000 Some use elevators, but they are a little more complex. 10 00:00:44,000 --> 00:00:47,000 We need to keep it simple. What is a simple machine? 11 00:00:47,000 --> 00:00:54,000 A simple machine is a device that makes work more convenient by changing the speed, direction, or amount of force. 12 00:00:54,000 --> 00:01:02,000 There are six simple machines, inclined plane, levers, wheel and axle, wedge, pulley, and a screw. 13 00:01:02,000 --> 00:01:08,000 We were thinking that a ramp might be the answer to our problem, but we didn't know that they were simple machines. 14 00:01:08,000 --> 00:01:10,000 Are there any requirements for ramps? 15 00:01:10,000 --> 00:01:18,000 If you want to build Jacob a ramp to get into the treehouse, the ramp will need to be built at a 12 to 1 ratio. 16 00:01:18,000 --> 00:01:22,000 That really helps. It gives us a lot to think about. See you later. 17 00:01:22,000 --> 00:01:26,000 I wonder if there are any other simple machines we need to use to solve our problem. 18 00:01:26,000 --> 00:01:28,000 We need to do more research. 19 00:01:31,000 --> 00:01:34,000 Look, Dr. D is balancing up on that big ball. 20 00:01:34,000 --> 00:01:36,000 I hope he doesn't fall off. 21 00:01:36,000 --> 00:01:39,000 Hi, Dr. D. It looks like you're having a great time. 22 00:01:48,000 --> 00:01:50,000 There's a lot of science here at the Circus Center. 23 00:01:50,000 --> 00:01:54,000 Science? I never knew that there could be science at a circus. 24 00:01:54,000 --> 00:01:59,000 Sure there is. The circus is a great place to get some ideas to help you solve your problem. 25 00:01:59,000 --> 00:02:02,000 We're particularly interested in simple machines. 26 00:02:02,000 --> 00:02:09,000 Great. Right now they're using a teeter board, which is a lever with a fulcrum or rotational point in the middle. 27 00:02:09,000 --> 00:02:10,000 How does it work? 28 00:02:10,000 --> 00:02:11,000 Let's watch them. 29 00:02:21,000 --> 00:02:27,000 That was pretty neat. I noticed that two men jumped on the board, but only one flew into the air. 30 00:02:27,000 --> 00:02:32,000 Those two men that jumped are called pitchers. The one that flew up in the air is called a flyer. 31 00:02:32,000 --> 00:02:34,000 I should have guessed that one. 32 00:02:34,000 --> 00:02:37,000 After the pitchers jump, they have a lot of potential energy. 33 00:02:37,000 --> 00:02:41,000 It looks like the flyer went at least twice as high as the pitchers. 34 00:02:41,000 --> 00:02:48,000 Exactly. Two men have the same energy as one man twice as high. The flyer also helps by pushing off the board. 35 00:02:49,000 --> 00:02:51,000 So the lever didn't create any energy. 36 00:02:51,000 --> 00:02:52,000 That's right. 37 00:02:52,000 --> 00:02:56,000 The lever changes the downward motion of the pitchers to the upward motion of the flyers. 38 00:02:56,000 --> 00:03:02,000 Correct. It's not magic. The teeter board just lets them transfer energy from the pitchers to the flyers. 39 00:03:02,000 --> 00:03:05,000 How would you like to experience the flying trapeze? 40 00:03:05,000 --> 00:03:07,000 That would be so cool. 41 00:03:07,000 --> 00:03:10,000 Now what does the flying trapeze have to do with energy? 42 00:03:12,000 --> 00:03:16,000 When you're way up there on the platform waiting, you have a lot of potential energy. 43 00:03:16,000 --> 00:03:20,000 Then when you grab the trapeze and swing down, you build up kinetic energy. 44 00:03:20,000 --> 00:03:24,000 And when you swing back again, you lose kinetic energy and pick up potential energy. 45 00:03:24,000 --> 00:03:28,000 Very good. So energy isn't being transferred like on the teeter board. 46 00:03:28,000 --> 00:03:33,000 It's just changing from potential energy to kinetic energy and then back again. 47 00:03:33,000 --> 00:03:37,000 That's why it's the acrobats on the aerial hoop. These guys are really something. 48 00:03:37,000 --> 00:03:41,000 Someone will have to do a lot of work to lift the hoop and the acrobat together. 49 00:03:42,000 --> 00:03:46,000 It looks really easy to pull them up. What are they using with the rope? 50 00:03:46,000 --> 00:03:48,000 It looks like they're using pulleys attached to the rope. 51 00:03:48,000 --> 00:03:52,000 I think this just might be the thing we need to pull Jacob up into the treehouse. 52 00:03:52,000 --> 00:03:55,000 This is great. We're making some real progress. Thanks, Dr. D. 53 00:03:55,000 --> 00:03:58,000 You're welcome. Let's see it by trapeze training.