WEBVTT - Why Does America Use Fahrenheit Instead of Celsius? 0:00:01.920 --> 0:00:07.080 Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff, 0:00:07.120 --> 0:00:10.080 Lauren bog Obam Here. If you're an American and you've 0:00:10.080 --> 0:00:12.480 ever had a conversation with someone from another country about 0:00:12.480 --> 0:00:15.240 the weather, you've probably been a little confused when he 0:00:15.400 --> 0:00:18.560 or she said, the afternoon temperature is a nice twenty 0:00:18.560 --> 0:00:21.800 one degrees. To you, that might sound like a chilly 0:00:21.800 --> 0:00:25.280 winter day, but to them it's a pleasantly warm springtime temperature. 0:00:26.200 --> 0:00:29.360 That's because virtually every other country throughout the world uses 0:00:29.400 --> 0:00:32.880 the Celsius temperature scale, part of the metric system, which 0:00:32.920 --> 0:00:36.240 denotes the temperature at which water freezes as zero degrees 0:00:36.479 --> 0:00:39.040 and the temperature at which it boils as a hundred degrees, 0:00:39.640 --> 0:00:42.680 but the US and a few other holdouts the Cayman Islands, 0:00:42.720 --> 0:00:46.600 the Bahamas, Belize, and Palau, cling to the fahrenheit scale, 0:00:46.800 --> 0:00:49.280 in which water freezes at thirty two degrees and boils 0:00:49.320 --> 0:00:52.440 at two hundred and twelve. That means that the twenty 0:00:52.440 --> 0:00:55.400 one degrees Celsie's temperature that we previously mentioned is the 0:00:55.440 --> 0:00:58.920 equivalent of a balmy seventy degrees fahrenheit. In the United States, 0:01:00.160 --> 0:01:03.840 the persistence of fahrenheit is one of those puzzling American idiosyncrasies, 0:01:03.960 --> 0:01:06.360 like how the US uses the word soccer to describe 0:01:06.360 --> 0:01:09.399 what the rest of the planet calls football. So why 0:01:09.480 --> 0:01:11.679 is it that the US uses a different temperature scale 0:01:11.880 --> 0:01:13.800 and why doesn't it switch to be consistent with the 0:01:13.800 --> 0:01:16.399 rest of the world. There doesn't seem to be a 0:01:16.440 --> 0:01:21.360 logical answer, except perhaps inertia. Americans generally seemed to distrust 0:01:21.400 --> 0:01:24.560 the metric system. A fifteen pole found that just one 0:01:25.000 --> 0:01:27.960 of the public favored converting to metric measures, while sixty 0:01:28.080 --> 0:01:31.600 four percent were opposed. It might make more sense if 0:01:31.600 --> 0:01:34.959 Fahrenheit was old school and Celsius was some modern upstart, 0:01:35.319 --> 0:01:38.200 sort of the new Coke of temperature, but in reality 0:01:38.240 --> 0:01:42.160 they were created only about two decades apart. Fahrenheit was 0:01:42.200 --> 0:01:46.240 created by its namesake, a German scientist named Daniel Gabriel Fahrenheit, 0:01:46.440 --> 0:01:48.720 who in the early seventeen hundreds was the first known 0:01:48.760 --> 0:01:51.920 person to design alcohol and mercury thermometers that were both 0:01:52.000 --> 0:01:55.080 precise and consistent, so that any two of his instruments 0:01:55.120 --> 0:01:57.559 would register the same temperature reading in a given place 0:01:57.600 --> 0:02:00.080 at a given moment, thanks to his working skill in 0:02:00.160 --> 0:02:04.000 managing glass. When Fahrenheit started out, the key thing he 0:02:04.080 --> 0:02:06.520 was interested in was coming up with the same temperature 0:02:06.520 --> 0:02:10.040 reading all the time, not comparing temperatures of different things 0:02:10.360 --> 0:02:13.400 or different times of day. But when he presented a 0:02:13.440 --> 0:02:16.000 paper on his system for measuring temperature to the Royal 0:02:16.040 --> 0:02:19.360 Society of London in seventeen twenty four, he apparently realized 0:02:19.360 --> 0:02:21.079 that he had to come up with a standard temperature 0:02:21.080 --> 0:02:24.880 scale as well. But we spoke with Don Hilger, a 0:02:24.960 --> 0:02:29.000 research meteorologist at Colorado State University's Cooperative Institute for Research 0:02:29.040 --> 0:02:31.520 in the Atmosphere and also president of the U S 0:02:31.520 --> 0:02:35.800 Metric Association, a group that advocates conversion to the metric system. 0:02:35.919 --> 0:02:39.520 He explained basically, the fahrenheit scale was devised was zero 0:02:39.639 --> 0:02:42.120 as the coldest temperature for a mix of ice and 0:02:42.160 --> 0:02:44.320 salt water, and the upper end was thought to be 0:02:44.360 --> 0:02:48.120 body temperature approximately nine degrees fahrenheit, making a scale that 0:02:48.120 --> 0:02:52.160 could be progressively divided by two. This resulted in the 0:02:52.200 --> 0:02:55.400 freezing melting temperature being thirty two degrees fahrenheit, not a 0:02:55.480 --> 0:02:58.320 very useful number. The boiling temperature for water was then 0:02:58.320 --> 0:03:01.360 set at two twelve, again not a very useful number. 0:03:01.760 --> 0:03:04.160 The two temperatures are a hundred and eighty degrees apart 0:03:04.320 --> 0:03:09.359 again a multiple of two. Nevertheless, the system apparently sounded 0:03:09.360 --> 0:03:12.160 pretty good to officials of the British Empire, who adopted 0:03:12.200 --> 0:03:15.400 fahrenheit as their standard temperature scale, which is how eventually 0:03:15.440 --> 0:03:19.320 became established in the American colonies as well. Meanwhile, though, 0:03:19.360 --> 0:03:23.080 in seventeen forty two, a Swedish astronomer named Anders Celsius 0:03:23.120 --> 0:03:25.800 came up with a less unwieldy system based on multiples 0:03:25.840 --> 0:03:28.400 of ten, in which there was precisely a one hundred 0:03:28.440 --> 0:03:31.320 degree difference between the freezing and boiling temperatures of water 0:03:31.440 --> 0:03:34.560 at sea level. The neat one hundred degrees symmetry of 0:03:34.639 --> 0:03:36.760 the Celsius scale made it a natural fit for the 0:03:36.760 --> 0:03:39.520 metric system, which was formally developed by the French in 0:03:39.560 --> 0:03:43.480 the late seventeen hundreds, but the English speaking world nevertheless 0:03:43.520 --> 0:03:46.400 clung stubbornly to its preference for awkward units such as 0:03:46.400 --> 0:03:48.960 the pound and the inch, and fahrenheit went along for 0:03:49.000 --> 0:03:53.200 the ride. But finally, in nineteen sixty one, the UK 0:03:53.360 --> 0:03:57.000 met Office then called the UK Meteorological Office, switched to 0:03:57.080 --> 0:04:00.680 using Celsius to describe temperatures in weather forecasts in order 0:04:00.720 --> 0:04:03.760 to be consistent with other European countries. Most of the 0:04:03.760 --> 0:04:06.240 rest of the world soon followed suit, with the notable 0:04:06.280 --> 0:04:09.119 exception of the US, where the National Weather Service still 0:04:09.160 --> 0:04:12.480 publishes temperature data in fahrenheit, even though its own staff 0:04:12.520 --> 0:04:17.240 long ago switched to celsius. Hilder explained the NWS as 0:04:17.279 --> 0:04:20.400 catering to the public by reporting in degrees fahrenheit, whereas 0:04:20.480 --> 0:04:24.080 much of their operations, such as forecast models, use degrees celsius, 0:04:24.520 --> 0:04:27.560 and for most automated weather observations the temperatures are recorded 0:04:27.600 --> 0:04:30.200 in celsius as well. Should we choose to go metric 0:04:30.240 --> 0:04:32.960 and weather reports, the fahrenheit layer that's now added for 0:04:33.000 --> 0:04:36.359 the u S public could be removed. We also spoke 0:04:36.440 --> 0:04:39.160 via email with j Hendrix, who heads the u S 0:04:39.279 --> 0:04:44.039 National Institute of Standards and Technologies Thermodynamic Meteorology Group. He 0:04:44.160 --> 0:04:47.000 points out that the fahrenheit scale does have one significant 0:04:47.000 --> 0:04:50.360 advantage a quote. It has more degrees over the range 0:04:50.360 --> 0:04:53.600 of ambient temperatures that are typical for most people. This 0:04:53.680 --> 0:04:56.960 means that there's a finer grain temperature difference between seventy 0:04:57.000 --> 0:05:00.320 degrees fahrenheit and seventy one degrees fahrenheit than there is 0:05:00.360 --> 0:05:03.359 between twenty one degree celsius and twenty two degree celsius. 0:05:03.960 --> 0:05:06.760 Since a human can tell the difference of one degree fahrenheit, 0:05:07.040 --> 0:05:10.760 this scale is more precise for the human experience. On 0:05:10.800 --> 0:05:13.080 the other hand, though, the advantage goes away if a 0:05:13.160 --> 0:05:17.560 fractional temperature in celsius is used. Hendricks explained. For example, 0:05:17.720 --> 0:05:20.960 the equivalent celsius temperature for seventy and seventy one fahrenheit 0:05:21.120 --> 0:05:23.560 are equivalent to twenty one point one and twenty one 0:05:23.600 --> 0:05:32.480 point seven degrees celsius. Today's episode was written by Patrick 0:05:32.560 --> 0:05:35.240 Jake Tiger and produced by Tyler Clang. Brain Stuff is 0:05:35.240 --> 0:05:37.600 a production of iHeart Radio's How Stuff Works. For more 0:05:37.640 --> 0:05:39.360 and this and lots of other topics that humans are 0:05:39.360 --> 0:05:42.520 sensitive to, visit our home planet how stuff Works dot com, 0:05:42.560 --> 0:05:44.720 and for our podcast from my heart Radio, visit the 0:05:44.760 --> 0:05:47.359 iHeart Radio app, Apple Podcasts, or wherever you listen to 0:05:47.400 --> 0:05:48.159 your favorite shows.