1 00:00:00,000 --> 00:00:05,000 Hey, Dr. D. I think he can hear you. You're so loud. 2 00:00:05,000 --> 00:00:09,000 Hi, guys. What brings you over? You look a little tired. 3 00:00:09,000 --> 00:00:12,000 Some of us are very tired. We didn't get any sleep. 4 00:00:12,000 --> 00:00:15,000 Both of our dogs were barking last night. 5 00:00:15,000 --> 00:00:18,000 Dr. D., did Bernie bark last night? 6 00:00:18,000 --> 00:00:22,000 Nah, you know Bernie. He's a little old. It's not like he's really out of it. 7 00:00:22,000 --> 00:00:24,000 Did Bernie ever bark? 8 00:00:24,000 --> 00:00:28,000 Oh, yeah, sure. Especially when he would smell or hear something he wasn't familiar with. 9 00:00:28,000 --> 00:00:30,000 He'd start barking to scare it off. 10 00:00:30,000 --> 00:00:35,000 So could there be a strange smell in the air that's making all of the dogs in the neighborhood start barking? 11 00:00:35,000 --> 00:00:40,000 Could be. I thought the trios detectives would be back working on another problem. 12 00:00:40,000 --> 00:00:42,000 So I made up this board. 13 00:00:42,000 --> 00:00:46,000 Oh, the scientific method. I'll let you in on a little something. 14 00:00:46,000 --> 00:00:49,000 The scientific method really helps you to solve problems. 15 00:00:49,000 --> 00:00:52,000 Well, it helped us with the sink problem. 16 00:00:52,000 --> 00:00:56,000 Remember, the scientific method is a step-by-step way to solve problems. 17 00:00:56,000 --> 00:00:58,000 You can use it every day. 18 00:00:58,000 --> 00:01:00,000 Oh, it's all coming back to me now. 19 00:01:00,000 --> 00:01:03,000 I have something fun to show you that will help us review the scientific method. 20 00:01:03,000 --> 00:01:05,000 Let's go to my lab and try it out. 21 00:01:05,000 --> 00:01:06,000 Okay. 22 00:01:10,000 --> 00:01:12,000 Does anyone know what this device is called? 23 00:01:12,000 --> 00:01:14,000 I've seen one before, but I don't know what it's called. 24 00:01:14,000 --> 00:01:16,000 Well, it's called a Newton's cradle. 25 00:01:16,000 --> 00:01:18,000 If you wanted to find out how it worked, what would you do? 26 00:01:18,000 --> 00:01:20,000 I guess I'd play around with it. 27 00:01:20,000 --> 00:01:25,000 If we're following the scientific method, then the first thing we would do is to identify the problem. 28 00:01:25,000 --> 00:01:27,000 And, of course, we'd have to observe it. 29 00:01:27,000 --> 00:01:30,000 Well, you're observing it already by playing with it. 30 00:01:30,000 --> 00:01:32,000 What do you think we can say is the problem? 31 00:01:32,000 --> 00:01:37,000 Well, I noticed that when I pull this ball back and then release it, another ball pops out. 32 00:01:37,000 --> 00:01:39,000 Does that happen every time? 33 00:01:39,000 --> 00:01:41,000 And what about two balls? 34 00:01:41,000 --> 00:01:43,000 That's the problem. 35 00:01:43,000 --> 00:01:46,000 Remember, a problem has to be stated in the form of a question. 36 00:01:46,000 --> 00:01:51,000 So our problem is, what happens to the balls on the other side when I pull back a certain number of balls? 37 00:01:51,000 --> 00:01:54,000 Isn't the next part of the scientific method research? 38 00:01:54,000 --> 00:01:55,000 Yeah, that's correct. 39 00:01:55,000 --> 00:01:57,000 Oh, I like this kind of research. 40 00:01:57,000 --> 00:01:59,000 Let's see what happens when I pull back two balls. 41 00:01:59,000 --> 00:02:01,000 I'll collect data. 42 00:02:01,000 --> 00:02:04,000 Whoa, wait a minute. Don't forget, we have to control the variables. 43 00:02:04,000 --> 00:02:07,000 All the variables are the same except for one. 44 00:02:07,000 --> 00:02:11,000 So pull back your two balls the same distance that Jacob pulled back his one. 45 00:02:11,000 --> 00:02:14,000 That's right. I forgot about those variables. 46 00:02:14,000 --> 00:02:17,000 Wait, what happens if I do three balls? 47 00:02:17,000 --> 00:02:19,000 Are we ready for our hypothesis yet? 48 00:02:19,000 --> 00:02:21,000 I know the hypothesis. 49 00:02:21,000 --> 00:02:23,000 When you let go of two balls, two balls come out. 50 00:02:23,000 --> 00:02:26,000 And if you let go of three balls, three balls come out. 51 00:02:26,000 --> 00:02:29,000 That's right. Remember, the hypothesis has to be written so it can be tested. 52 00:02:29,000 --> 00:02:34,000 For example, the same number of balls I pull back will come out on the other side. 53 00:02:34,000 --> 00:02:36,000 Okay, are we ready to experiment yet? 54 00:02:36,000 --> 00:02:38,000 That's my favorite part. 55 00:02:38,000 --> 00:02:40,000 Okay, let's test the hypothesis. 56 00:02:40,000 --> 00:02:41,000 Let's see what happens. 57 00:02:41,000 --> 00:02:45,000 If I pull back four balls, then four balls should come out on the other side. 58 00:02:52,000 --> 00:02:55,000 Wow, our hypothesis was correct. 59 00:02:55,000 --> 00:02:57,000 Congratulations. 60 00:02:57,000 --> 00:03:01,000 But remember, the data does not support the hypothesis you have to try again. 61 00:03:01,000 --> 00:03:04,000 But how do we observe for our problem of the barking dogs? 62 00:03:04,000 --> 00:03:07,000 We can't stay up all night waiting for the dogs to start barking. 63 00:03:07,000 --> 00:03:09,000 Well, we could. 64 00:03:09,000 --> 00:03:12,000 Not me. Remember, I have that big test next week. 65 00:03:12,000 --> 00:03:15,000 I think we need to go back to the tree house to talk about this problem. 66 00:03:15,000 --> 00:03:18,000 And then we need to decide what we want to research. 67 00:03:18,000 --> 00:03:20,000 Thanks for all your help, Dr. Dean. 68 00:03:20,000 --> 00:03:21,000 See you, Dr. Dean. 69 00:03:21,000 --> 00:03:22,000 Bye-bye, guys.