1 00:00:00,000 --> 00:00:02,000 Hi, I'm Kia. 2 00:00:02,000 --> 00:00:03,000 And I'm Justin. 3 00:00:03,000 --> 00:00:05,000 You must be the treehouse detectives. 4 00:00:05,000 --> 00:00:06,000 Yes, we are. 5 00:00:06,000 --> 00:00:09,000 And I'm trying to avoid infectious bacteria. 6 00:00:09,000 --> 00:00:12,000 We need to learn more about how infectious diseases spread. 7 00:00:12,000 --> 00:00:13,000 We can help. 8 00:00:13,000 --> 00:00:15,000 Our mentor from the Society of Women Engineers 9 00:00:15,000 --> 00:00:18,000 helped us with a great experiment that simulates an epidemic. 10 00:00:18,000 --> 00:00:21,000 An epidemic occurs when the majority of people in a group 11 00:00:21,000 --> 00:00:23,000 all get an infectious disease. 12 00:00:23,000 --> 00:00:25,000 How do you simulate an epidemic? 13 00:00:26,000 --> 00:00:30,000 First, our teacher, Ms. Fracker, prepared the test tubes for each student. 14 00:00:30,000 --> 00:00:33,000 All the test tubes had water in them except for one, 15 00:00:33,000 --> 00:00:35,000 which had a solution of ammonia. 16 00:00:35,000 --> 00:00:37,000 But we didn't know which one was which. 17 00:00:37,000 --> 00:00:38,000 Why only one? 18 00:00:38,000 --> 00:00:41,000 To simulate the student who has the cold virus. 19 00:00:41,000 --> 00:00:42,000 What did you do next? 20 00:00:42,000 --> 00:00:45,000 We each used an eyedropper to exchange four drops of fluid 21 00:00:45,000 --> 00:00:49,000 with four other people to simulate an exchange of body fluids, 22 00:00:49,000 --> 00:00:51,000 such as eating or drinking after another person. 23 00:00:51,000 --> 00:00:55,000 We also made sure to record the name of the person we exchanged the fluid with. 24 00:00:55,000 --> 00:00:56,000 Why was that important? 25 00:00:56,000 --> 00:01:00,000 We wanted to see if we could trace the virus back to the original person. 26 00:01:00,000 --> 00:01:02,000 How could you tell who was infected? 27 00:01:02,000 --> 00:01:05,000 After we finished exchanging the fluids, 28 00:01:05,000 --> 00:01:08,000 Ms. Fracker added a hundred drops of an indicator 29 00:01:08,000 --> 00:01:11,000 made from cabbage leaves to our test tubes. 30 00:01:11,000 --> 00:01:13,000 If the test tube was infected, 31 00:01:13,000 --> 00:01:16,000 it changed color to yellow, green, blue, or purple. 32 00:01:16,000 --> 00:01:18,000 Why the different colors? 33 00:01:18,000 --> 00:01:21,000 The color differences were due to the amount of ammonia in each test tube. 34 00:01:21,000 --> 00:01:23,000 The infected test tube turned yellow, 35 00:01:23,000 --> 00:01:26,000 and the ones with the next greatest amount of ammonia turned green. 36 00:01:26,000 --> 00:01:29,000 The ones that were only slightly infected with ammonia turned blue, 37 00:01:29,000 --> 00:01:32,000 and the ones that weren't infected at all turned purple. 38 00:01:32,000 --> 00:01:33,000 I understand. 39 00:01:33,000 --> 00:01:38,000 The test tubes with the most ammonia had the most exposure to the cold virus. 40 00:01:38,000 --> 00:01:39,000 That's correct. 41 00:01:39,000 --> 00:01:42,000 That particular student had exchanged or been exposed to the virus 42 00:01:42,000 --> 00:01:44,000 more than the other students. 43 00:01:44,000 --> 00:01:46,000 How many students were infected at the end of the experiment? 44 00:01:46,000 --> 00:01:49,000 12 out of 15 students were infected. 45 00:01:49,000 --> 00:01:52,000 That's 80% that contracted the cold virus. 46 00:01:52,000 --> 00:01:54,000 It's good to know that not all students were infected. 47 00:01:54,000 --> 00:01:55,000 Yes, it is. 48 00:01:55,000 --> 00:01:58,000 And it's even better to know that you can prevent the spread of disease 49 00:01:58,000 --> 00:02:01,000 by not exchanging body fluids with other people. 50 00:02:01,000 --> 00:02:04,000 To be safe, it's best not to eat or drink after anyone 51 00:02:04,000 --> 00:02:06,000 and to try to avoid contact with sick people. 52 00:02:06,000 --> 00:02:08,000 That's good advice. 53 00:02:08,000 --> 00:02:09,000 Thanks for all your help. 54 00:02:09,000 --> 00:02:11,000 You're welcome. Anytime. 55 00:02:11,000 --> 00:02:13,000 Good luck, Jacob. Hope you stay well. 56 00:02:13,000 --> 00:02:15,000 And thanks to SWE for all their help. 57 00:02:16,000 --> 00:02:19,000 Goodbye from Sigsbee Elementary School in Key West, Florida.