WEBVTT - How Meteorologists Work 0:00:04.200 --> 0:00:12.520 Get technology with tech Stuff from dot Com. Hey there, 0:00:12.560 --> 0:00:16.320 and welcome to tech Stuff. I am your host, Jonathan Strickland. 0:00:16.400 --> 0:00:20.040 I'm a senior writer win how Stuff Works dot Com, 0:00:20.079 --> 0:00:24.560 and sometimes my voice cracks for no reason. Today we're 0:00:24.560 --> 0:00:28.680 going to continue our journey into the scary world of 0:00:28.800 --> 0:00:32.600 weather forecasting. Uh. I say scary because weather is a 0:00:32.640 --> 0:00:37.040 powerful thing. It can bring with it some pretty intense 0:00:37.800 --> 0:00:41.279 uh storms and and win things like that. I mean, 0:00:41.320 --> 0:00:43.760 obviously you can have nice weather too, but who wants 0:00:43.760 --> 0:00:45.559 to talk about that? I mean, you're not gonna have 0:00:45.680 --> 0:00:51.120 an emergency weather broadcast burst into your favorite viewing time 0:00:51.159 --> 0:00:55.200 of watching ALF and say warning, things are gonna be 0:00:55.240 --> 0:01:00.120 really nice this afternoon. So we're gonna talk about today 0:01:00.000 --> 0:01:02.840 about some of the tools that meteorologists use in order 0:01:02.880 --> 0:01:06.880 to get information about what's going on at this very 0:01:06.880 --> 0:01:10.840 moment as far as the weather is concerned. In our 0:01:10.920 --> 0:01:14.720 last episode, we covered the basics of how weather works, 0:01:14.760 --> 0:01:17.319 so that man, it was more of a science based show, 0:01:17.480 --> 0:01:20.440 less technology, but it was important so that we can 0:01:20.520 --> 0:01:25.960 build the foundation to understand why meteorology is so incredibly 0:01:26.080 --> 0:01:29.720 complicated and so process or heavy. Like when you talk 0:01:29.880 --> 0:01:34.840 about supercomputers. One of the main uses for supercomputers these 0:01:34.920 --> 0:01:38.480 days is to run weather models. And that's because you're 0:01:38.480 --> 0:01:41.399 talking about an enormous amount of data that has to 0:01:41.440 --> 0:01:44.959 be processed running you know, various types of calculations on 0:01:45.040 --> 0:01:47.880 it in order to create the outputs that we use 0:01:47.960 --> 0:01:51.760 for weather forecasts. And as our weather models become more 0:01:51.880 --> 0:01:59.560 and more high resolution, more precise, using more more readings 0:01:59.600 --> 0:02:05.640 per hour, that demand of processing power increases quite a bit. 0:02:06.080 --> 0:02:09.520 So let's talk about just the stuff that meteorologists used 0:02:09.560 --> 0:02:12.640 to gather that data. This isn't even about the weather models. 0:02:12.639 --> 0:02:16.240 In our next episode, we will cover how weather models work, 0:02:16.480 --> 0:02:19.680 because it's fascinating all in its own. Today we're gonna 0:02:19.720 --> 0:02:23.840 focus on the stuff that meteorologists used to get the 0:02:23.919 --> 0:02:28.400 data that feeds into those weather models. Uh So, meteorologists 0:02:28.600 --> 0:02:31.120 do a few different things. They do make observations of 0:02:31.120 --> 0:02:34.760 current weather conditions, so they're telling you what's happening right now, 0:02:34.840 --> 0:02:38.080 and that's what I'm focusing on for this episode and 0:02:38.120 --> 0:02:40.680 the next one will look more at the forecasting side. 0:02:40.760 --> 0:02:45.480 How do they actually predict what will happen next. Observations 0:02:45.520 --> 0:02:48.640 let you know the current conditions. They include data like 0:02:48.760 --> 0:02:54.520 wind speed, wind direction, air pressure, temperature, humidity, u V, 0:02:55.639 --> 0:03:00.000 radiation numbers, smog fog, all of these things and more. 0:03:00.000 --> 0:03:04.240 Are you need observation stations throughout any given region, the 0:03:04.280 --> 0:03:09.080 region that you are responsible for, let's say, and you 0:03:09.120 --> 0:03:10.600 need to have a lot of them in order for 0:03:10.639 --> 0:03:13.440 you to get a more complete picture of what is 0:03:13.560 --> 0:03:17.840 really actually happening. If you have only a few observation points, 0:03:18.200 --> 0:03:20.920 then you would have what we would call low resolution. 0:03:21.400 --> 0:03:24.240 You would not have a very accurate accurate view of 0:03:24.240 --> 0:03:26.639 what was going on within the region, unless your region 0:03:26.720 --> 0:03:32.720 is particularly small. Let's say that you are responsible for 0:03:32.919 --> 0:03:37.000 gathering the information across an entire county. Well, a county 0:03:37.040 --> 0:03:41.560 could be lots of square mileage, and depending upon where 0:03:41.560 --> 0:03:46.360 your observation stations are, you might have information that's very 0:03:46.360 --> 0:03:49.120 relevant for a specific part of that county, but it 0:03:49.240 --> 0:03:52.160 might not be so relevant for other parts of the county. 0:03:52.360 --> 0:03:55.080 And yet you have to create weather forecasts based on 0:03:55.120 --> 0:03:57.800 your observations. It means the further out you go from 0:03:57.800 --> 0:04:02.200 those observation stations, the less reliable that data is going 0:04:02.240 --> 0:04:04.880 to be because it may not reflect what the actual 0:04:04.960 --> 0:04:10.040 conditions are further away from those observation stations. So having 0:04:10.040 --> 0:04:13.120 a high density of observation stations is critical for having 0:04:13.440 --> 0:04:17.520 very precise, whether a picture of what's going on with 0:04:17.520 --> 0:04:22.000 the weather and thus making more accurate weather forecasts. So 0:04:22.560 --> 0:04:25.120 it could cause a problem, right Like, you could end 0:04:25.200 --> 0:04:28.640 up giving a weather forecast that ends up being useless 0:04:28.760 --> 0:04:33.039 for a significant percentage of the people who are relying 0:04:33.120 --> 0:04:35.960 upon your weather forecasts if they happen to live far 0:04:36.000 --> 0:04:40.479 away from where your observation stations are. So let's think 0:04:40.480 --> 0:04:43.960 of this in more concrete terms and you'll really understand 0:04:44.040 --> 0:04:46.040 how this can become a problem. Let's say that you 0:04:46.120 --> 0:04:51.320 have a region that includes some different areas within with 0:04:51.400 --> 0:04:53.800 different levels of elevation. So let's say that you're at 0:04:53.800 --> 0:04:56.000 the foothills of a mountain range. Well, we'll say this 0:04:56.120 --> 0:05:01.120 the appal Achians. So, uh, I live in Atlanta, Georgia, 0:05:01.240 --> 0:05:04.400 where on what is called the Piedmont it is h 0:05:05.720 --> 0:05:10.120 hilly but not mountainous area. If I were further northeast 0:05:10.839 --> 0:05:14.120 of here, or even just further north of here, I 0:05:14.160 --> 0:05:17.040 would start getting into the foothills of the Appalachian Mountains. 0:05:17.839 --> 0:05:20.640 So let's say that I'm on Just like that, I'm 0:05:20.680 --> 0:05:23.680 looking at a region where it's covering the end of 0:05:23.720 --> 0:05:27.960 the Piedmont into the foothills. That's several different areas of 0:05:28.000 --> 0:05:31.880 different elevation. That means that those different areas are going 0:05:31.920 --> 0:05:36.239 to experience different weather patterns because weather is all about 0:05:36.240 --> 0:05:39.920 atmospheric movement and things that are going on within the atmosphere. 0:05:40.200 --> 0:05:44.520 Atmosphere is going to move over the topographical features of 0:05:44.520 --> 0:05:48.479 any given region, the geography, and with hills and mountains, 0:05:48.760 --> 0:05:51.400 that means the weather is going to do different things 0:05:51.839 --> 0:05:57.119 in those different areas. So you're going to have folks 0:05:57.200 --> 0:05:59.400 checking the weather report and wondering why it says there's 0:05:59.440 --> 0:06:02.800 no chance brain while they're being rained on, and it 0:06:02.839 --> 0:06:06.600 may be because they live on the opposite side of 0:06:06.640 --> 0:06:10.159 a mountain from where you are with your observation stations, 0:06:10.560 --> 0:06:13.960 and at the observation stations everything's bone dry because that's 0:06:13.960 --> 0:06:16.719 what you know, that's what you've based your forecast on, 0:06:16.720 --> 0:06:19.240 because that was where the data was coming from. But 0:06:19.320 --> 0:06:21.840 on the other side of the mountain, because you've had 0:06:21.880 --> 0:06:25.040 warm air masses pushed up to higher elevations as they 0:06:25.080 --> 0:06:29.000 moved over a mountain, They've then cooled down, water has condensed, 0:06:29.400 --> 0:06:32.200 and precipitation has begun to fall. People on the other 0:06:32.279 --> 0:06:34.320 side of the mountain they get rained on, and yet 0:06:34.320 --> 0:06:37.240 they're living in that same region that's being covered by you, 0:06:38.279 --> 0:06:41.520 because that's the county they are in, or the zip code. 0:06:42.279 --> 0:06:45.119 This is why it gets really problematic when you start 0:06:45.160 --> 0:06:50.359 making weather forecasts, because they depend so heavily upon the 0:06:50.400 --> 0:06:55.800 geography of the respective regions and the geography and and 0:06:55.920 --> 0:06:58.800 observation stations within that geography. Now, if you have observation 0:06:58.839 --> 0:07:02.280 stations throughout your area, you can give much more precise 0:07:02.720 --> 0:07:06.120 weather forecasts. And say, in this part of the county, 0:07:06.320 --> 0:07:09.760 you would expect conditions to be dry, but up here 0:07:09.880 --> 0:07:12.160 over in the mountains, you're gonna start seeing some rain. 0:07:13.160 --> 0:07:16.440 So you start seeing where the complexity comes into play. 0:07:16.480 --> 0:07:20.480 And this is a very small scale example of this problem. 0:07:20.520 --> 0:07:24.080 Once you start looking at it from say a statewide 0:07:24.440 --> 0:07:28.720 or nationwide or global perspective, you begin to realize this 0:07:28.800 --> 0:07:32.320 is really complicated stuff, and this is a big challenge 0:07:32.320 --> 0:07:35.720 for meteorologists. You might notice that many weather apps allow 0:07:35.800 --> 0:07:39.040 you to search for weather forecasts by zip codes, but again, 0:07:39.120 --> 0:07:43.360 zip codes do not necessarily conform to geography, and you 0:07:43.400 --> 0:07:46.679 could have lots of different geographic regions within a single 0:07:46.760 --> 0:07:49.680 zip code, and that means that the weather forecast for 0:07:49.760 --> 0:07:52.560 one of those parts of the zip code may not 0:07:52.640 --> 0:07:54.880 be accurate for all the other parts. So if I 0:07:54.960 --> 0:07:57.000 check my app and it says hey, it's gonna rain, 0:07:57.320 --> 0:08:00.280 and I step outside and it's sunny, I might think, well, 0:08:00.320 --> 0:08:03.520 what the heck is wrong with this weather forecast app? Again, 0:08:03.560 --> 0:08:05.680 they have to try and give you a forecast that's 0:08:06.120 --> 0:08:09.560 going to be relevant for the entire zip code, even 0:08:09.600 --> 0:08:12.400 if different parts of that zip code are in different 0:08:13.080 --> 0:08:18.520 geographical regions, like different geographical features mountains or streams or 0:08:18.600 --> 0:08:24.280 lakes or ocean or whatever it may be. So you 0:08:24.360 --> 0:08:28.360 can't really take all that into account if your criteria 0:08:28.440 --> 0:08:32.000 for generating a forecast is based solely upon zip codes. 0:08:32.600 --> 0:08:35.160 That's why a lot of different weather apps and services 0:08:35.200 --> 0:08:38.240 are now using geolocation data to give you a more 0:08:38.280 --> 0:08:42.040 precise weather forecast for your your requests. So, if you're 0:08:42.040 --> 0:08:44.800 carrying a mobile device and you have a weather app 0:08:44.840 --> 0:08:47.160 on it and it's asking hey, can I have access 0:08:47.200 --> 0:08:51.120 to your GPS or location data? If you say yes, 0:08:51.920 --> 0:08:55.800 then the weather app can look for your location and 0:08:55.840 --> 0:09:01.360 try and base the forecast for you closer to observation 0:09:01.440 --> 0:09:06.160 stations that are relevant to your your actual location So 0:09:06.200 --> 0:09:07.520 if I happen to be in a part of the 0:09:07.559 --> 0:09:13.520 county that is not the main population center and thus 0:09:13.600 --> 0:09:16.800 not the place that the forecast is really gonna cater to, 0:09:17.360 --> 0:09:19.960 I might get something more personalized saying, hey, well, based 0:09:20.000 --> 0:09:22.920 upon where you are, you're gonna be Charlie Brown and 0:09:22.960 --> 0:09:25.440 have a little cloud follow you all day raining just 0:09:25.720 --> 0:09:28.440 on you, which has never quite happened to me, but 0:09:28.480 --> 0:09:31.160 some days it feels that way. It's sidesteps that zip 0:09:31.200 --> 0:09:34.360 code problem, so that the weather forecasting system can consult 0:09:34.400 --> 0:09:38.640 the observation stations really closest to you at that time 0:09:38.679 --> 0:09:43.200 and to project weather based upon that. But even then 0:09:43.240 --> 0:09:45.360 you can still run into issues. So, for example, if 0:09:45.360 --> 0:09:48.480 you happen to be closest to an airport observation station, 0:09:48.800 --> 0:09:51.480 I mean most really all airports have some form of 0:09:51.520 --> 0:09:56.040 meteorological meteor logical boy man, that's gonna be a lot 0:09:56.080 --> 0:10:03.360 of fun today. Meteorological observation stations. Almost all air airports 0:10:03.400 --> 0:10:07.920 have at least some element of that, because clearly the 0:10:07.960 --> 0:10:10.840 weather conditions are very important when it comes to air travel. 0:10:12.360 --> 0:10:16.520 One problem with that is that airports have very big 0:10:16.600 --> 0:10:21.680 runways and uh tarmax things that absorb a lot of 0:10:21.720 --> 0:10:24.040 heat and give off a lot of heat, more so 0:10:24.120 --> 0:10:26.920 than the surrounding area. And as we learned in our 0:10:27.000 --> 0:10:30.360 last episode, heat is a big important factor when it 0:10:30.400 --> 0:10:33.280 comes to impacting weather systems. So if you happen to 0:10:33.280 --> 0:10:37.520 be close to an airport, that might end up throwing 0:10:37.600 --> 0:10:41.480 off some of the readings that you would get because 0:10:41.760 --> 0:10:44.120 it has this island effect right at the airport, But 0:10:44.160 --> 0:10:47.640 that might not extend very far outside of the airport's borders. 0:10:48.520 --> 0:10:51.200 So while you're getting observation data that's close to you, 0:10:51.760 --> 0:10:55.240 it may still not be relevant to you. A lot 0:10:55.280 --> 0:10:58.320 of this sounds like I'm apologizing for weather forecasts that 0:10:58.400 --> 0:11:01.720 aren't entirely accurate, and I guess you could argue that 0:11:01.760 --> 0:11:05.040 I kind of am. But mostly what I want to 0:11:05.200 --> 0:11:09.079 stress is just, um, what a tough job this is. 0:11:10.200 --> 0:11:13.400 It's an interesting and fascinating thing, and we've learned so 0:11:13.480 --> 0:11:17.880 much about atmospheric fluid dynamics and just how weather works 0:11:17.880 --> 0:11:21.080 in general as a result of lots and lots of 0:11:21.080 --> 0:11:24.640 men and women putting their heads together and and making 0:11:24.640 --> 0:11:29.320 observations and sussing all this out. But it's still really 0:11:29.320 --> 0:11:31.480 really hard to do, which is why it's one of 0:11:31.480 --> 0:11:37.920 the reasons why we don't do it perfectly now. Besides resolution, 0:11:38.160 --> 0:11:41.240 as in how many observation stations you have within a 0:11:41.320 --> 0:11:45.520 given region, you have to take those observations frequently. This 0:11:45.600 --> 0:11:49.440 helps with precision. If you take one observation in the day, 0:11:49.480 --> 0:11:52.160 early in the day, and that's it, then you can't 0:11:52.200 --> 0:11:56.360 take into account any changes that happen afterward, which means 0:11:56.360 --> 0:11:59.679 that you can never really update your forecast. And that 0:11:59.720 --> 0:12:03.240 means that the further away you get in time from 0:12:03.280 --> 0:12:08.160 that initial observation, the less precise and accurate your forecast 0:12:08.240 --> 0:12:11.640 is going to be. If you continuously or at least 0:12:11.679 --> 0:12:16.080 regularly take observations, you can then update your forecast as 0:12:16.120 --> 0:12:20.959 a result when conditions change, and that way you can 0:12:21.200 --> 0:12:25.840 keep your at least your immediate forecast more accurate. You 0:12:25.880 --> 0:12:28.959 may notice that the further out you go from the 0:12:29.040 --> 0:12:36.760 point of forecast from the current time, the less accurate 0:12:37.480 --> 0:12:39.800 these forecasts tend to tend to be. So if you're 0:12:39.800 --> 0:12:43.280 looking at a date that's ten days out, it might 0:12:43.320 --> 0:12:45.480 be more or less right on the money, or maybe 0:12:45.559 --> 0:12:49.240 way off base. Because weather is again very complicated and 0:12:49.280 --> 0:12:54.080 constantly changing. Uh So you want to make sure that 0:12:54.120 --> 0:12:58.040 the information you're relying on doesn't age so much as 0:12:58.080 --> 0:13:02.079 to be irrelevant. So you need lots of observation stations. 0:13:02.520 --> 0:13:05.720 You need to take a lot of observations per given 0:13:05.800 --> 0:13:08.400 unit of time, and the combination of those two requirements 0:13:08.480 --> 0:13:13.200 means that you are generating an enormous amount of data 0:13:13.320 --> 0:13:16.000 that then has to go someplace and then be processed 0:13:16.000 --> 0:13:18.240 for you to get forecasts. This is why you need 0:13:18.280 --> 0:13:24.120 those hefty computers like supercomputers to process meteorological data. And 0:13:24.160 --> 0:13:26.800 more on that in the next episode. But first let's 0:13:26.800 --> 0:13:30.520 talk about some of the basic instruments these meteorologists are 0:13:30.640 --> 0:13:34.680 using to gather actual weather data. Then in our next 0:13:34.679 --> 0:13:36.760 episode will move on to how they use that to 0:13:36.840 --> 0:13:40.840 create models for weather. And also why are there different models. 0:13:40.960 --> 0:13:44.800 You've probably heard of various weather models. Why do we 0:13:44.840 --> 0:13:47.800 not just have one? Why are there multiples? And why 0:13:47.840 --> 0:13:52.280 are some quote unquote better than others in very specific scenarios. 0:13:52.760 --> 0:13:55.720 We're going to cover that in the next episode. Now, 0:13:55.760 --> 0:14:00.520 generally speaking, meteorological instruments fall into two broadcat gregories. You 0:14:00.559 --> 0:14:05.880 have direct sensors also called institute sensors. They're inside the 0:14:05.960 --> 0:14:09.480 situation like a thermometer that is left out to measure 0:14:09.559 --> 0:14:14.360 the temperature of the air. It's institute. It is a 0:14:14.840 --> 0:14:19.600 direct sensor. It's directly measuring the temperature of the air outside. 0:14:20.680 --> 0:14:25.000 Then you have remote sensors that are measuring something that's 0:14:25.120 --> 0:14:29.400 much further away. The name pretty much gives you the 0:14:29.440 --> 0:14:31.360 indication of what it does. Now, we're going to talk 0:14:31.400 --> 0:14:36.360 about both types in this episode. Direct sensors include lots 0:14:36.360 --> 0:14:38.520 of stuff that you're familiar with, and we're gonna start 0:14:38.520 --> 0:14:42.040 off with a good old, easy one to to talk 0:14:42.080 --> 0:14:48.480 about thermometers, the noble thermometer telling us such information like dude, 0:14:49.000 --> 0:14:51.280 it's wicked cold out that today, but on your coat, 0:14:51.800 --> 0:14:54.960 or seriously, buddy, it's boiling out there. Let's play some 0:14:55.040 --> 0:14:59.240 player unknowns battlegrounds in the air conditioned house. But how 0:14:59.320 --> 0:15:04.280 do thermommeters actually work? So let's start with your basic 0:15:04.360 --> 0:15:08.400 mercury thermometer. It's something that is still being used around 0:15:08.480 --> 0:15:11.800 the world. It's your basic bulb thermometer. It depends upon 0:15:11.840 --> 0:15:16.040 a simple physical principle, which is that a liquids volume 0:15:16.400 --> 0:15:20.680 changes relative to the temperature of the liquid. So when 0:15:20.680 --> 0:15:23.880 you heat a liquid up, it's molecules decide to do 0:15:23.920 --> 0:15:26.840 the equivalent of the guy I'm always seated next to 0:15:27.000 --> 0:15:31.000 on a long distance plane ride. In other words, it 0:15:31.040 --> 0:15:36.000 spreads out well beyond its normal parameters. You know who 0:15:36.000 --> 0:15:40.840 I'm talking about. Give me my arm rest back. But 0:15:40.840 --> 0:15:42.520 that's what happens with liquids. You heat them up, the 0:15:42.600 --> 0:15:46.120 molecules get more energy, they get excited, they move around more, 0:15:46.160 --> 0:15:49.960 and they spread apart. So as a result, the liquid expands, 0:15:50.000 --> 0:15:52.240 and if, of course you do this long enough, the 0:15:52.400 --> 0:15:56.040 liquid will end up turning into a gas, which is 0:15:56.240 --> 0:16:02.880 even more free form than liquid. Obvious asleep. When liquids 0:16:03.120 --> 0:16:08.240 get cold, those molecules end up huddling together, not so 0:16:08.360 --> 0:16:10.480 much for warmth, but because they have less energy they 0:16:10.520 --> 0:16:13.680 don't move around so much, so the liquid actually takes 0:16:13.760 --> 0:16:16.640 up less space than it normally would. So your basic 0:16:16.680 --> 0:16:20.400 bulb thermometer consists of a small bulb at the base 0:16:21.040 --> 0:16:25.760 and a narrow, long, closed tube leading up from that 0:16:25.880 --> 0:16:31.520 bulb base. These physical proportions accentuate the change in volume 0:16:31.680 --> 0:16:34.720 of the liquid, So you want the bulb to be 0:16:34.800 --> 0:16:38.720 small because you want any changes in temperature in whatever 0:16:38.840 --> 0:16:44.160 environment you are measuring to rapidly be reflected within the 0:16:44.160 --> 0:16:49.960 thermometer itself. So, for example, if you're talking about outside. 0:16:50.000 --> 0:16:53.800 Any drastic change in the outside temperature, you want that 0:16:53.880 --> 0:16:58.200 to be reflected in an outside thermometer pretty quickly. Typically 0:16:58.400 --> 0:17:03.480 those temperatures don't increase or drop that fast. But let's 0:17:03.480 --> 0:17:07.359 say you want to go from room temperature thermometer and 0:17:07.400 --> 0:17:10.159 you're testing someone's temperature. You want to find out they 0:17:10.160 --> 0:17:12.280 have a fever or not. You don't want to have 0:17:12.320 --> 0:17:15.119 to wait a very long time for that change in 0:17:15.160 --> 0:17:20.159 temperature to UH to happen within the mercury inside that thermometer. 0:17:20.520 --> 0:17:22.879 So that's why that bulb is small. It's just a 0:17:22.880 --> 0:17:25.840 small amount of liquid. Doesn't change take very long for 0:17:25.880 --> 0:17:28.480 that change in temperature to move through the liquid, and 0:17:28.520 --> 0:17:36.800 thus the volume increases inside the the thermometer. UH. With weather, 0:17:37.520 --> 0:17:41.120 it means you you'd want something that will remain liquid 0:17:41.320 --> 0:17:44.159 at temperatures found across most of the planet, which is 0:17:44.200 --> 0:17:48.920 why we use mercury. Mercury is a metal. It is 0:17:49.000 --> 0:17:51.719 a metal that is liquid at room temperature and a 0:17:51.720 --> 0:17:55.480 lot of temperatures that you will find on Earth. Very 0:17:55.560 --> 0:17:58.880 useful in that sense, it's not going to boil away 0:17:59.000 --> 0:18:03.040 rapidly at high a temperatures, nor does it freeze at 0:18:03.960 --> 0:18:06.359 your typical low temperatures. When you get two very low, 0:18:06.720 --> 0:18:10.480 which does happen on Earth, mercury will free So it's 0:18:10.480 --> 0:18:15.440 not perfect, but it's reliable and it's easy to read 0:18:15.520 --> 0:18:19.119 the differences. It's um it shows up well in a 0:18:19.240 --> 0:18:24.800 glass thermometer, and as it turns out, uh, mercury liquid 0:18:24.800 --> 0:18:29.000 mercury is is pretty reliable. It remains liquid at temperatures 0:18:29.040 --> 0:18:31.960 that range from six D seventy four degrees fahrenheit, which 0:18:31.960 --> 0:18:35.720 is three D fifty six point seventy three degrees celsius, 0:18:35.760 --> 0:18:38.480 all the way down to its freezing point of minus 0:18:38.520 --> 0:18:42.320 thirty eight fahrenheit or minus thirty eight point eight three celsius. 0:18:42.840 --> 0:18:45.040 But hey, here's a fun fact. The most extreme cold 0:18:45.080 --> 0:18:48.520 temperatures on Earth get way below minus thirty eight celsius. 0:18:49.240 --> 0:18:53.080 In fact, in NASA released satellite data that measured the 0:18:53.160 --> 0:18:58.119 lowest recorded temperature at minus ninety four point seven celsius, 0:18:58.119 --> 0:19:01.960 which is minus one thirty five point eight fahrenheit. At 0:19:02.000 --> 0:19:06.000 that temperature, mercury itself would freeze. So for very low 0:19:06.040 --> 0:19:10.360 temperatures you cannot use a mercury thermometer. You just you're 0:19:10.400 --> 0:19:12.960 not gonna it's gonna be as cold as it gets. 0:19:12.960 --> 0:19:15.919 It's already frozen. It's a solid, so you actually have 0:19:15.960 --> 0:19:18.400 to use a different kind of liquid. If you want 0:19:18.400 --> 0:19:23.359 to use a liquid thermometer, alcohol works. Uh. They call 0:19:23.440 --> 0:19:26.640 them spirit thermometers in the old days because you're talking 0:19:26.640 --> 0:19:31.080 about spirits alcohol. Alcohol is a very low freezing point, 0:19:31.240 --> 0:19:34.880 and it's boiling point, however, is much lower than mercury, 0:19:34.920 --> 0:19:37.359 so you can't use it for very high temperature things, 0:19:37.600 --> 0:19:40.680 you know, but it works great for low temperature applications. 0:19:41.480 --> 0:19:44.240 And uh, this actually leads me to an interesting question 0:19:44.440 --> 0:19:47.520 that I think is fun to tackle, even though it's 0:19:47.560 --> 0:19:51.879 not not quite as technical. How did we come up 0:19:51.920 --> 0:19:55.719 with the fahrenheit and celsius scales? Well, it all has 0:19:55.760 --> 0:19:58.680 to do with the freezing and boiling points of water, 0:19:59.240 --> 0:20:02.000 which makes sense. Water is very prevalent here on Earth. 0:20:02.160 --> 0:20:04.600 Most of our surface of our planet is covered in water. 0:20:05.240 --> 0:20:10.040 We depend upon water for our survival, so the temperatures 0:20:10.040 --> 0:20:13.640 at which water will freeze or boil are obviously important 0:20:13.680 --> 0:20:17.320 to us. So fahrenheit will start with that because that 0:20:17.520 --> 0:20:22.320 scale was proposed first. That came from Daniel Danny Boy 0:20:22.480 --> 0:20:26.080 fahrenheit in fourteen and as far as I know, no 0:20:26.119 --> 0:20:28.159 one else called him Danny Boy, but I'm waiting for 0:20:28.200 --> 0:20:31.960 it to catch On fourteen, he decided to use a 0:20:32.000 --> 0:20:34.879 scale designed actually by a predecessor of his. It was 0:20:34.960 --> 0:20:39.240 not it was not completely invented by Fahrenheit. He took 0:20:39.280 --> 0:20:42.879 a scale that was made by a man named Olaus Rummer. 0:20:43.600 --> 0:20:49.840 Rummer's thermometer listed zero as the lowest point. That was 0:20:49.880 --> 0:20:52.239 not the freezing point, but it was as low as 0:20:52.280 --> 0:20:55.919 the thermometer could register. Was zero and at seven point 0:20:56.040 --> 0:21:01.480 five on Rumors scale, that's where I would melt into water, 0:21:01.760 --> 0:21:04.800 or if you prefer where water would freeze into ice. 0:21:05.000 --> 0:21:08.440 It is the freezing point or melting point, depending upon 0:21:08.440 --> 0:21:12.960 your perspective. That was seven and a half on or 0:21:13.119 --> 0:21:17.080 scale at twenty two and a half that was considered 0:21:17.119 --> 0:21:21.960 body temperature, and sixty was the temperature for boiling water. 0:21:22.240 --> 0:21:25.320 So it went from zero to sixty with boiling water 0:21:25.359 --> 0:21:28.120 being at the top and freezing being at about seven 0:21:28.119 --> 0:21:33.439 and a half fahrenheit to create a mercury thermometer, and 0:21:33.560 --> 0:21:37.640 it was capable of making more precise measurements than the 0:21:37.640 --> 0:21:40.800 the spirit thermometer that Rumor had been using. And because 0:21:40.840 --> 0:21:45.960 of that precision, since you could measure smaller changes in temperature, 0:21:46.800 --> 0:21:49.120 fair Kneit felt that there needed to be a scale 0:21:49.480 --> 0:21:52.919 that would be broader than than Rumor's scale so that 0:21:52.960 --> 0:21:58.680 you could easily talk about tiny changes in temperature. Right, 0:21:59.400 --> 0:22:03.520 it's just getting an extra level of precision in there, 0:22:04.560 --> 0:22:08.040 and it means that you don't have to subdivide those 0:22:08.160 --> 0:22:11.240 units into further and further decimal points in order to 0:22:11.320 --> 0:22:16.760 describe the differences of temperature changes. So Fahrenheit ended up 0:22:16.800 --> 0:22:22.199 first taking rumor scale and he multiplied it by four. Uh. 0:22:22.240 --> 0:22:24.720 He then adjusted the scale. He started doing some research 0:22:24.760 --> 0:22:27.359 and realized that just multiplying it by four it meant 0:22:27.359 --> 0:22:30.240 that it wasn't as accurate as it needed to be. 0:22:30.960 --> 0:22:33.800 He had more levels of precision, but the accuracy was off. 0:22:33.880 --> 0:22:39.040 Multiplying it by four it multiplied not just the scale 0:22:39.359 --> 0:22:44.879 but also the imprecision of that original scale. So he 0:22:44.960 --> 0:22:48.160 started to try and refine it. Fahrenheit ended up after 0:22:48.160 --> 0:22:51.080 he passed away, people took his scale and began to 0:22:51.080 --> 0:22:54.800 refine it more, and they began to establish the freezing 0:22:54.840 --> 0:22:59.119 point and boiling point of water, and decided to set 0:22:59.160 --> 0:23:02.880 the freezing point and boiling point apart by one eighty degrees, 0:23:03.760 --> 0:23:06.440 which is important in math, but not so great for 0:23:06.880 --> 0:23:11.320 just casual conversation, So some people would say it was 0:23:11.400 --> 0:23:13.239 kind of an arbitrary decision to make it a one 0:23:13.840 --> 0:23:17.600 degree difference between freezing and boiling. The temperature of freezing 0:23:17.600 --> 0:23:20.880 water was eventually established as thirty two degrees, which means 0:23:20.920 --> 0:23:25.080 boiling water would be two hundred twelve degrees. One benefit 0:23:25.119 --> 0:23:27.280 of the scale was that the units would allow for 0:23:27.400 --> 0:23:31.080 subtle descriptions of temperature changes without the need for decimals. 0:23:31.160 --> 0:23:33.560 So if you were to describe the temperature as rising 0:23:33.600 --> 0:23:37.800 from eighty six to eighty seven in fahrenheit, that's easy. 0:23:37.880 --> 0:23:40.000 But if you wanted to say the same thing in celsius, 0:23:40.040 --> 0:23:44.040 to take those same two temperatures and talk about that increase, 0:23:44.359 --> 0:23:47.560 you'd say it went from thirty degrees celsius to thirty 0:23:47.600 --> 0:23:51.800 point six degrees celsius, or so if you said thirty 0:23:51.800 --> 0:23:54.879 one celsius, you're not being as precise because that's a 0:23:54.960 --> 0:23:58.600 greater change in temperature than what you're actually referring to. 0:23:59.320 --> 0:24:01.680 Now that being at having the temperature for freezing water 0:24:01.720 --> 0:24:04.919 set at thirty two degrees is a bit frustrating, but 0:24:05.000 --> 0:24:07.600 I think I have an explanation for this. This is 0:24:07.720 --> 0:24:11.760 Jonathan's supposition corner. I kind of wish I could get 0:24:11.840 --> 0:24:14.399 Dylan to make a musical sting for this. That just 0:24:14.480 --> 0:24:20.639 sounds confusing. All right, here's here's my pitch. Why is 0:24:21.480 --> 0:24:23.920 water freezing at thirty two degrees? Why is it thirty 0:24:23.920 --> 0:24:26.320 two degrees? Why is it not zero? Why would you 0:24:26.359 --> 0:24:30.160 not start at zero for the freezing point of water? 0:24:30.280 --> 0:24:33.040 If water is the really important part on your scale, 0:24:33.760 --> 0:24:40.359 it's because it can get colder than freezing here on Earth. 0:24:41.359 --> 0:24:46.000 And so you've got fahrenheit saying, well, I want a 0:24:46.080 --> 0:24:49.240 scale that I can measure the temperature even when it's 0:24:49.240 --> 0:24:52.200 colder than freezing, because some days it is colder than freezing, 0:24:52.359 --> 0:24:54.239 so I need my scale to be able to reflect that. 0:24:54.680 --> 0:24:59.280 But how do I measure that? If I've set freezing 0:24:59.760 --> 0:25:02.680 as zero? Where do I go from there? I mean, 0:25:02.720 --> 0:25:08.199 I can't have the mercury go further down. I've got it. 0:25:08.320 --> 0:25:12.000 I'll set freezing higher up on the scale, And that 0:25:12.040 --> 0:25:15.520 way you can still describe stuff that's colder than freezing water, 0:25:16.000 --> 0:25:19.800 but not colder than what I can measure. So, uh, 0:25:20.800 --> 0:25:22.560 you set the bottom of your scale lower than the 0:25:22.560 --> 0:25:24.920 temperature for freezing. In that way, every measurement you take 0:25:25.000 --> 0:25:28.240 is a positive unit, you don't have to create negative units, 0:25:28.720 --> 0:25:30.640 So you just set your scales based at the temperature 0:25:30.640 --> 0:25:33.080 lower than what it tends to get down to. Right. 0:25:33.240 --> 0:25:37.000