WEBVTT FILE 1 00:00:00.000 --> 00:00:03.750 Measure. Analyze. Learn. 2 00:00:04.000 --> 00:00:06.000 This is the Carbon Dioxide Sensor. 3 00:00:06.000 --> 00:00:09.000 It's used in several of our lab manuals; 4 00:00:09.000 --> 00:00:12.500 It shows up in the biology manual, the physiology manual. 5 00:00:12.500 --> 00:00:15.250 And so, it's used to measure the concentration 6 00:00:15.250 --> 00:00:18.000 of carbon dioxide gas. 7 00:00:18.000 --> 00:00:19.750 So, you always want to make sure you are doing a gas. 8 00:00:19.750 --> 00:00:23.000 You don't ever put this into a liquid. 9 00:00:23.000 --> 00:00:26.000 And, the way this sensor operates, it actually uses an 10 00:00:26.000 --> 00:00:30.750 IR detector, and so, it has an infrared source, 11 00:00:30.750 --> 00:00:35.000 that if the CO2 goes through these holes, 12 00:00:35.000 --> 00:00:38.500 the CO2 will absorb some of the infrared radiation 13 00:00:38.500 --> 00:00:40.000 from the detector. 14 00:00:40.000 --> 00:00:43.000 And, the higher the concentration of the CO2 gas 15 00:00:43.000 --> 00:00:46.000 the less infrared makes it to the detector. 16 00:00:46.000 --> 00:00:49.750 Now, since this is using an IR source, you do need to 17 00:00:49.750 --> 00:00:52.500 let it warm up for 90 seconds, when you use it. 18 00:00:52.500 --> 00:00:56.000 So, when you plug it in, at first, it actually, will not give you 19 00:00:56.000 --> 00:00:59.500 a correct reading, until it is ready for collection. 20 00:00:59.500 --> 00:01:04.000 Another thing about that, is that if using this outside, 21 00:01:04.000 --> 00:01:07.250 you would like to avoid having this in direct sunlight, 22 00:01:07.250 --> 00:01:11.000 because you end up warming this up, and you can cause 23 00:01:11.000 --> 00:01:13.500 a change in how the units reading there. 24 00:01:13.500 --> 00:01:15.000 So, you want to avoid that. 25 00:01:15.000 --> 00:01:17.500 Now, this is a dual range sensor. 26 00:01:18.000 --> 00:01:21.000 And so, there is a sensor setting switch here. 27 00:01:21.000 --> 00:01:23.250 So, it's a sensitivity switch. 28 00:01:23.250 --> 00:01:27.250 The low range is a 0 to 10,000 parts per million. 29 00:01:27.750 --> 00:01:30.250 A lot of the experiments will use that. 30 00:01:30.750 --> 00:01:34.750 And then, the higher range is 0 to 100,000 parts per million. 31 00:01:34.750 --> 00:01:36.750 You might need to use that, if you are going to, you know, 32 00:01:36.750 --> 00:01:38.000 breath on it, or something like that. 33 00:01:39.000 --> 00:01:42.500 The sensor in general doesn't need to be calibrated, 34 00:01:42.500 --> 00:01:46.350 but you can, and to do the calibration, 35 00:01:46.350 --> 00:01:49.250 it's important that you put it into a known condition. 36 00:01:49.500 --> 00:01:52.500 Take the Nalgene bottle that comes with it, 37 00:01:52.600 --> 00:01:54.750 and you could collect a sample of air, 38 00:01:54.750 --> 00:01:57.000 and it has a lid that you can put on it. 39 00:01:57.000 --> 00:01:59.000 And, you could bring it back in and do the 40 00:01:59.000 --> 00:02:00.750 calibration that way if you wanted to. 41 00:02:01.000 --> 00:02:04.750 There is a calibration port right here. 42 00:02:04.750 --> 00:02:07.000 And, you can take, maybe, a paper clip, 43 00:02:07.000 --> 00:02:12.000 and press down on this until it, the unit, stabilizes. 44 00:02:12.000 --> 00:02:15.500 It will end up with a reading of 380 parts per million. 45 00:02:15.500 --> 00:02:19.000 Then we assume that's what it is outside, in open air. 46 00:02:19.000 --> 00:02:20.000 And then, you're good to go. 47 00:02:20.250 --> 00:02:24.000 To use this, we suggest that you would use it with 48 00:02:24.000 --> 00:02:26.000 several different chambers that we have. 49 00:02:26.000 --> 00:02:28.000 I just mentioned this Nalgene bottle. 50 00:02:28.000 --> 00:02:30.000 This is the one that comes with it. 51 00:02:30.000 --> 00:02:34.500 Another option is to use this BioChamber 250. 52 00:02:34.500 --> 00:02:37.500 And, this allows you to put more than one sensor in, 53 00:02:37.500 --> 00:02:40.000 if you would like. So, you could put a CO2, 54 00:02:40.000 --> 00:02:43.000 and maybe an oxygen sensor in there. So, you can use that one. 55 00:02:43.250 --> 00:02:46.000 In addition to that, we have the BioChamber 2000. 56 00:02:46.000 --> 00:02:49.750 And, it allows us to put two sensors in a container. 57 00:02:49.750 --> 00:02:53.500 And so, it has two holes, so we could put a CO2 sensor here, 58 00:02:53.500 --> 00:02:55.500 maybe an oxygen sensor there, 59 00:02:55.500 --> 00:02:58.500 and measure both of those two things simultaneously. 60 00:02:59.500 --> 00:03:04.750 Again, you might use this with labs like the respiration of peas. 61 00:03:04.750 --> 00:03:06.500 It's one I'm going to use here. 62 00:03:06.500 --> 00:03:09.000 You could use it with, maybe put some crickets, 63 00:03:09.000 --> 00:03:12.000 or worms in there, and look at their respiration rate. 64 00:03:12.000 --> 00:03:15.500 Fermentation of yeast; so you're producing CO2 65 00:03:15.500 --> 00:03:18.000 from the fermentation. You might use it that way. 66 00:03:18.000 --> 00:03:21.250 Some chemical reactions that generate CO2 gas. 67 00:03:21.250 --> 00:03:23.500 And so, anything that is generating the CO2 gas, 68 00:03:23.500 --> 00:03:25.250 you would use this device. 69 00:03:25.250 --> 00:03:28.000 So now, were ready to, maybe, collect a little data. 70 00:03:28.000 --> 00:03:33.250 And, we need to plug in the CO2 sensor to our LabQuest. 71 00:03:33.250 --> 00:03:36.000 And so, I'm going to plug it in here. 72 00:03:36.000 --> 00:03:41.000 And so it's, once it goes in, right now the device is 73 00:03:41.000 --> 00:03:44.000 reading 0 parts per million. 74 00:03:44.000 --> 00:03:45.750 And, we said it need to warm up. 75 00:03:45.750 --> 00:03:49.500 And, it will continue to give us a reading like that, 76 00:03:49.500 --> 00:03:52.000 until it is warmed up. 77 00:03:52.000 --> 00:03:55.750 And so, that takes about 90 seconds for that to warm up. 78 00:03:55.750 --> 00:03:57.250 And, I want to make sure that I have this 79 00:03:57.250 --> 00:03:59.000 on that lower range setting there. 80 00:03:59.000 --> 00:04:03.500 While that's warming up, what I'm going to do is take my peas; 81 00:04:03.500 --> 00:04:05.500 and these are some peas that I started soaking 82 00:04:05.500 --> 00:04:09.000 a couple of days ago. There actually sprouting at this point. 83 00:04:09.000 --> 00:04:12.750 And so, there probably producing a lot of CO2. 84 00:04:12.750 --> 00:04:16.000 And, I'm going to place them into my bottle there. 85 00:04:16.000 --> 00:04:20.500 There's about 25, or so, peas there. 86 00:04:20.500 --> 00:04:25.000 And so, I'll just put those there. 87 00:04:25.000 --> 00:04:29.250 And now, there we go. So our unit is now reading here. 88 00:04:29.250 --> 00:04:34.000 And so, inside our room here, we've got about 89 00:04:34.000 --> 00:04:36.000 600-and-something parts per million. 90 00:04:36.250 --> 00:04:38.500 So, if we look at our collection parameters 91 00:04:38.500 --> 00:04:41.000 in the upper right corner here; we see 'Time Based'; 92 00:04:41.000 --> 00:04:44.500 meaning that it is a variable is as a function of time; 93 00:04:44.500 --> 00:04:47.000 so, CO2 concentration with time. 94 00:04:47.000 --> 00:04:51.250 The default rate is .25 samples per second. 95 00:04:51.500 --> 00:04:55.500 So actually, every 4 seconds it's going to make a measurement. 96 00:04:55.500 --> 00:05:00.250 It can go faster than that, but because we're measuring 97 00:05:00.250 --> 00:05:04.000 the CO2 that has to diffuse through these holes, 98 00:05:04.000 --> 00:05:06.000 it may not change all that rapidly. 99 00:05:06.000 --> 00:05:09.500 So, collecting data faster than, say, four points per second, 100 00:05:09.500 --> 00:05:11.250 you really don't have to do that. 101 00:05:11.250 --> 00:05:13.000 And, you end up generating more, 102 00:05:13.000 --> 00:05:15.000 maybe more, data than you want, to be able to do that. 103 00:05:15.000 --> 00:05:17.500 So, you need to allow time for that CO2 104 00:05:17.500 --> 00:05:19.500 to make it into the sensor there. 105 00:05:19.500 --> 00:05:22.500 And then, if we look at our default time for this. 106 00:05:22.750 --> 00:05:26.250 It actually is a 600 seconds, so it's a 10 minute. 107 00:05:26.250 --> 00:05:28.000 And, that's fine for a lot of experiments. 108 00:05:28.000 --> 00:05:30.500 And, in fact, for this one we'll just use that 109 00:05:30.500 --> 00:05:32.500 as our default setting here. 110 00:05:32.500 --> 00:05:35.500 So, I've put my peas into my bottle, 111 00:05:35.500 --> 00:05:40.000 and I want to put the sensor into here. 112 00:05:40.000 --> 00:05:44.500 One suggestion that we have here, is that you actually run 113 00:05:44.500 --> 00:05:49.750 the experiment on its side here, because that CO2 gas is heavy. 114 00:05:49.750 --> 00:05:52.000 It tends to form a layer down towards the bottom 115 00:05:52.000 --> 00:05:54.750 of the container, and if you do it upright, it may take 116 00:05:54.750 --> 00:05:57.000 longer time for it to diffuse, and you end up with 117 00:05:57.000 --> 00:05:58.500 a kind of layering effect there. 118 00:05:58.500 --> 00:06:02.750 And so, once we've done this, we're ready to collect the data. 119 00:06:02.750 --> 00:06:06.000 And, to begin collection, all we need to do is press 120 00:06:06.000 --> 00:06:09.500 the collect button. And, we press collect. 121 00:06:09.500 --> 00:06:13.000 And, it's now going to collect for 10 minutes. 122 00:06:13.000 --> 00:06:16.000 And, we'll watch what happens to the concentration 123 00:06:16.000 --> 00:06:17.500 of the gas in the container. 124 00:06:23.000 --> 00:06:25.000 So, we've finished our data collection. 125 00:06:25.000 --> 00:06:28.750 And, it looks like our CO2 level was increasing nicely there. 126 00:06:28.750 --> 00:06:31.750 And, we might want to run some analysis here. 127 00:06:31.750 --> 00:06:36.500 So, it looks like our CO2 was increasing fairly constantly there. 128 00:06:36.500 --> 00:06:38.250 So, why don't we run a curve fit, 129 00:06:38.250 --> 00:06:40.750 and maybe look at something about the rate. 130 00:06:40.750 --> 00:06:43.250 So, I'm going to go to 'Analyze'. 131 00:06:43.250 --> 00:06:47.250 And, I'm going to go down to where it says 'Curve Fit'. 132 00:06:47.250 --> 00:06:49.250 And, I will check the box next to 'CO2'. 133 00:06:50.750 --> 00:06:54.750 And so now, I need to, maybe, try my equation here. 134 00:06:54.750 --> 00:06:58.750 It looks linear to me, so I'm going to try a 'Linear' fit. 135 00:06:58.750 --> 00:07:00.750 And, there we get our fit. 136 00:07:00.750 --> 00:07:02.750 And I will say 'OK'. 137 00:07:03.500 --> 00:07:09.750 And, it looks like it fits nicely, and we have a slope there of 138 00:07:09.750 --> 00:07:14.500 4.4 parts per million per second, there. 139 00:07:14.500 --> 00:07:16.500 So, it's increasing at a constant rate. 140 00:07:17.000 --> 00:07:22.500 So again, this sensor is used widely for biology and 141 00:07:22.500 --> 00:07:25.500 biology related experiments. 142 00:07:25.500 --> 00:07:28.000 It's definitely a good one to have. 143 00:07:28.000 --> 00:07:31.000 And, it allows you to measure things that would be 144 00:07:31.000 --> 00:07:32.750 very difficult to do other ways.