1 00:00:00,000 --> 00:00:03,000 Hello, we're on time, but we do need your help. 2 00:00:03,000 --> 00:00:06,000 Our help? Aren't you the famous investigative team? 3 00:00:06,000 --> 00:00:09,000 Okay, so you saw us on KSNN last night? 4 00:00:09,000 --> 00:00:10,000 How can we help? 5 00:00:10,000 --> 00:00:13,000 We have a ton of information to go through. 6 00:00:13,000 --> 00:00:19,000 A lot of residents have emailed us to let us know if they smelled a bad stink. 7 00:00:19,000 --> 00:00:21,000 So what have you done so far? 8 00:00:21,000 --> 00:00:24,000 We started out by writing down what we knew about the problem. 9 00:00:24,000 --> 00:00:28,000 We asked a lot of questions, wrote down a bunch of new questions, 10 00:00:28,000 --> 00:00:30,000 and talked to a lot of experts. 11 00:00:30,000 --> 00:00:32,000 So here's what we know about the problem. 12 00:00:32,000 --> 00:00:35,000 The Fuseville Health Department gave a warning on Monday 13 00:00:35,000 --> 00:00:40,000 that a lot of people in the town were smelling a bad smell. 14 00:00:40,000 --> 00:00:43,000 But no one knows where the smell is coming from. 15 00:00:43,000 --> 00:00:46,000 We need to figure out what's causing the stink. 16 00:00:46,000 --> 00:00:50,000 We asked the residents to email us to report if they found anything. 17 00:00:50,000 --> 00:00:54,000 So we were sort of hoping that you could help us to gather the comments. 18 00:00:54,000 --> 00:00:56,000 Wow, look at all that email. 19 00:00:56,000 --> 00:00:58,000 What do we do with it? 20 00:00:58,000 --> 00:01:02,000 How about if we start by separating them by the cities? 21 00:01:02,000 --> 00:01:06,000 Fuseville, Mid-City, Exville, and Big City. 22 00:01:06,000 --> 00:01:09,000 Yeah, and then we can separate them into two PALs, 23 00:01:09,000 --> 00:01:11,000 one for Monday and one for Tuesday. 24 00:01:11,000 --> 00:01:13,000 That will help us to chart it down. 25 00:01:19,000 --> 00:01:24,000 Phew, look, nobody smelled anything in Big City or Mid-City on either day. 26 00:01:24,000 --> 00:01:29,000 This is weird. Look at all the people in Exville who said they smelled the usual on both days. 27 00:01:29,000 --> 00:01:31,000 The usual? 28 00:01:31,000 --> 00:01:36,000 And a couple of people said they think it's a paper mill and they're not worried. 29 00:01:36,000 --> 00:01:39,000 Hey, look, here's the paper mill over here. 30 00:01:39,000 --> 00:01:42,000 And it's north of Exville. 31 00:01:42,000 --> 00:01:46,000 And look, the trash burning plant is over here too. 32 00:01:46,000 --> 00:01:51,000 But almost everyone in Fuseville said that they smelled something really bad on Monday, 33 00:01:51,000 --> 00:01:53,000 but not on Tuesday. 34 00:01:53,000 --> 00:01:55,000 So maybe it really is the paper mill. 35 00:01:55,000 --> 00:02:01,000 Well, it would have knocked them out in Exville if it was so bad in Fuseville on Monday. 36 00:02:01,000 --> 00:02:06,000 But Fuseville didn't smell anything on Tuesday when Exville still did. 37 00:02:06,000 --> 00:02:09,000 Maybe something kept the smell from getting there on Tuesday. 38 00:02:09,000 --> 00:02:12,000 Maybe we should do an experiment on how smell moves. 39 00:02:12,000 --> 00:02:14,000 Experiment? Cool. 40 00:02:14,000 --> 00:02:16,000 Wait a minute. 41 00:02:16,000 --> 00:02:19,000 Nobody in Mid-City smelled it on either day. 42 00:02:19,000 --> 00:02:22,000 And look, it's right next to the chemical plant. 43 00:02:22,000 --> 00:02:24,000 Hmm, this is really strange. 44 00:02:24,000 --> 00:02:26,000 Could we be wrong? 45 00:02:26,000 --> 00:02:29,000 Maybe the chemical plant isn't causing all the stink. 46 00:02:29,000 --> 00:02:32,000 But yesterday we figured out that it was the chemical plant. 47 00:02:32,000 --> 00:02:34,000 I still think it is. 48 00:02:34,000 --> 00:02:36,000 That's our hypothesis, remember? 49 00:02:36,000 --> 00:02:38,000 But we might be wrong. 50 00:02:38,000 --> 00:02:40,000 We need an expert opinion. 51 00:02:40,000 --> 00:02:42,000 Let's go back and tell Dr. D after school. 52 00:02:42,000 --> 00:02:44,000 He might be able to tell us if we're right. 53 00:02:44,000 --> 00:02:46,000 Let's go. 54 00:02:53,000 --> 00:02:55,000 Hi, Dr. D. 55 00:02:55,000 --> 00:02:57,000 Hello again. What's wrong? 56 00:02:57,000 --> 00:02:59,000 You look like your cat just died. 57 00:02:59,000 --> 00:03:01,000 No, that didn't happen. 58 00:03:01,000 --> 00:03:03,000 Wishful thinking, Bernie. 59 00:03:03,000 --> 00:03:05,000 We thought we had the problem all figured out. 60 00:03:05,000 --> 00:03:09,000 We thought the stink was coming from the chemical plant. 61 00:03:09,000 --> 00:03:11,000 Look at this. 62 00:03:11,000 --> 00:03:14,000 But if the stink was coming from the chemical plant, 63 00:03:14,000 --> 00:03:17,000 the people in Mid-City would definitely smell it. 64 00:03:17,000 --> 00:03:19,000 But they didn't. 65 00:03:20,000 --> 00:03:22,000 It might have been the paper mill. 66 00:03:22,000 --> 00:03:26,000 But why didn't the people in Exville smell it really strong on Monday? 67 00:03:26,000 --> 00:03:31,000 And then why didn't the people in Fuseville smell it on Tuesday? 68 00:03:31,000 --> 00:03:35,000 Either people are smelling it differently or something else is going on. 69 00:03:35,000 --> 00:03:39,000 I was thinking maybe we could do an experiment to see how smell travels. 70 00:03:39,000 --> 00:03:41,000 What would your variables be then? 71 00:03:41,000 --> 00:03:43,000 Variables? 72 00:03:43,000 --> 00:03:45,000 Remember what Monica Barnes said? 73 00:03:45,000 --> 00:03:47,000 Remember what Monica Barnes said? 74 00:03:47,000 --> 00:03:52,000 It's one specific thing that you, the experimenter, has control over. 75 00:03:52,000 --> 00:03:56,000 It can affect or change the results of your experiment. 76 00:03:56,000 --> 00:03:59,000 That's right. Let's use my wave machine as an example. 77 00:03:59,000 --> 00:04:02,000 When I wiggle this rod, it makes waves of medium height. 78 00:04:02,000 --> 00:04:06,000 The distance between waves we call the wavelength. 79 00:04:06,000 --> 00:04:08,000 How can we change the wavelength? 80 00:04:08,000 --> 00:04:13,000 I think if you wiggle the rods faster, it will make the wavelength shorter. 81 00:04:13,000 --> 00:04:16,000 No. The wavelength will be longer. 82 00:04:16,000 --> 00:04:21,000 Frequency, or how fast I wiggle the rod, is a variable because it affects the wavelength. 83 00:04:21,000 --> 00:04:24,000 It's important to only change one variable at a time. 84 00:04:24,000 --> 00:04:27,000 Like not changing the weight at all. 85 00:04:27,000 --> 00:04:33,000 That's right. If we change the wave height, making it bigger or smaller, that might also affect the wavelength. 86 00:04:33,000 --> 00:04:39,000 Let's try it. I'll wiggle the rods at a faster frequency, at medium height, and see what happens. 87 00:04:39,000 --> 00:04:42,000 Yes! I ruled! The wavelength was shorter. 88 00:04:42,000 --> 00:04:44,000 Did that help you remember? 89 00:04:44,000 --> 00:04:48,000 Kind of. I guess we need to think through about how a smell moves. 90 00:04:48,000 --> 00:04:52,000 Okay. Let's go back to the treehouse and get to work. Bye! 91 00:04:52,000 --> 00:04:54,000 Bye-bye! See you later, Dr. D!