Editing 1643: Degrees

{{comic
| number    = 1643
| date      = February 15, 2016
| title     = Degrees
| image     = degrees.png
| titletext = "Radians Fahrenheit or radians Celsius?" "Uh, sorry, gotta go!"
}}

==Explanation==
[[Cueball]] is being asked by a friend for the {{w|temperature}}. While he is checking his smartphone for the weather, he begins pondering what unit he should use when answering the question. (See below for [[#Cueball's reasoning|Cueball's reasoning]].)

In the US (where Cueball and [[Randall]] are from), the {{w|Conversion of units of temperature|temperature scale}} used in daily life is {{w|Fahrenheit}}.  However, most of the rest of the world uses {{w|Celsius}} in daily life, and even in the US it is commonly used for science. This is also why Randall has previously made the comic [[526: Converting to Metric]]. There are also people who wish the US to change to the metric system, although some of them still wish to keep the Fahrenheit scale as mentioned in [[1982: Evangelism]]

:'''The Celsius scale''' is from the {{w|metric system}}. Though this system has been officially sanctioned for use in the US since 1866, it is not frequently used in daily American life (except for some things, like liter bottles of soda), although it is the preferred system for trade and commerce according to the {{w|Metric Conversion Act}} of 1975. The US remains the only industrialized country, and one of few countries period, that does not use the metric system for everyday measurements, and in which official government documents and signage do not enforce metric units. The unit ''degree Celsius'' or °C is an accepted {{w|International System of Units#Derived units|derived unit}} from the {{w|International System of Units}} (SI units) used in science (which again is the modern form of the metric system). The SI unit of temperature is the {{w|kelvin}}, but this temperature scale is linearly related to the Celsius scale, which is why Celsius can be derived from it.
:'''The Fahrenheit scale''' is from the {{w|United States customary units|US customary system}} and the (British) {{w|Imperial units|imperial system}}. The unit is ''degree Fahrenheit'' or °F, and the relation to the Celsius scale is not easy to find in a mental calculation. The relations are: [°F] = [°C]×9⁄5 + 32 or [°C] = ([°F] − 32)×5⁄9. (For this exact reason Randall has previously made a helpful table for these situations in [[526: Converting to Metric]].)

Unlike most areas of measurement, where the metric system is widely considered superior, there is considerable debate about the relative merits of Fahrenheit vs. Celsius. Cueball weighs up the benefits of both scales, but fails to find a solution he can live with, and since he feels he has to give his friend an answer now, he panics and gives the answer 0.173 {{w|radians}}.
:'''Radian''' is the standard unit of angular measure, used in many areas of mathematics. An angle's measurement in radians is numerically equal to the length of a corresponding arc of a {{w|unit circle}}. It has no units and is denoted with the superscript <sup>c</sup>, but more commonly <sup>rad</sup>, lest it be confused with {{w|Degree (angle)|angular degrees}}. One radian is an angle of approximately 57.3 degrees.
:'''Angular degrees''' is a system used to measure {{w|angles}} in {{w|geometry}}, and although it too uses the symbol ° and the word "degrees", it has nothing to do with temperature measurements of any sort. Potentially he is referring to a monitor on his phone that is giving him data on which he is deliberating.

Thus, this answer is unhelpful and the joke is that traditionally both geometric angles and temperature are measured in "degrees", but there is no connection between the two. 

The title text indicates that Cueball's friend still wants to know whether the answer is in radians Fahrenheit or radians Celsius, which, despite being a silly way to express temperature, would actually enable the friend to get some meaning out of the reply. But this just takes Cueball back to the problem he failed to solve in the first place of choosing one scale in preference to the other, so suddenly he announces has to go and runs off without ever clarifying what he meant. This result is probably because he is afraid of being a bad friend according to his very last point regarding Fahrenheit: ''Valuing unit standardization over being helpful possibly makes me a bad friend.''

The answer Cueball gives of 0.173 radians corresponds to a geometric angle 9.91° (0.173 × <sup>360°</sup>/<sub>2π</sub>). If this were "radians Celsius" it would be 9.91&nbsp;°C corresponding to 49.8&nbsp;°F and if it were "radians Fahrenheit" it would be 9.91&nbsp;°F corresponding to -12.3&nbsp;°C. [http://boston.cbslocal.com/2016/02/13/new-england-freezing-temperatures-valentines-day-weekend/ Given the temperatures] in {{w|Massachusetts}} (where Randall lives) when this comic came out, the day after Valentine's Day 2016, Cueball was probably giving his answer in radians Fahrenheit.

=== Cueball's reasoning ===
==== Degrees Celsius ====
;International standard
:Degrees Celsius is derived unit in the SI system of units used to measure temperature in most countries today. Using the SI system would allow Cueball to be easily understood in most countries and is by far the most recognized system, but it is not the most commonly used in the United States, his presumed location in the comic.
;Helps reduce America's weird isolationism
:The United States uses its own set of units, including degrees Fahrenheit, called the {{w|United States customary system}} (similar but not equal to the imperial system), in contrast to most of the rest of the world, which uses the SI system. The US's system of units is therefore considered "weird" as it makes the US different from most of the world, but previous efforts to convert the US to the SI system have failed. Cueball evidently believes that by using SI units, he will help to eventually convert the US to the SI system, bringing considerable trade and tourism benefits and reducing confusion when dealing with foreigners.
;Nice how "negative" means below freezing
:On the Celsius scale, the freezing point of water at standard atmospheric pressure (101.325 kilopascals) is very close to 0&nbsp;°C, and any temperature below that is below the freezing point. The Fahrenheit scale uses different points of reference (using a water/ammonium chloride chemical reaction for the lower calibration, while the upper calibration is set such that water freezing and water boiling are 180 degrees apart), and as a result the freezing point of water is a less memorable 32&nbsp;°F.
;Physics major loyalty
:Cueball is apparently a physics major, like Randall, and SI units are more commonly used for scientific work (as the kelvin scale is sometimes used in physics and other sciences), even in the US. By using the Celsius scale in casual conversation, he would show his loyalty to the system used by actual physicists.
;Easier to spell
:"Celsius" is generally considered to be an easier word to spell than the German surname "Fahrenheit" (at least this is the case for Cueball, but not necessarily for those who more commonly use Fahrenheit than Celsius). In this case the word is being spoken and the point is not immediately relevant, but part of the joke is that Cueball is overthinking things and worrying about the general use of the word when an answer is needed in this specific case.
;We lost a Mars probe over this crap
:The {{w|Mars Climate Orbiter|Mars Climate Orbiter}} disintegrated in Mars' atmosphere because Lockheed used US customary units instead of the contractually specified metric units. This had nothing to do with temperature scales, but was the use of the unit pound-seconds where newton-seconds should have been used. This was a great and tragic loss for science in general, Mars exploration in particular, and thus also for Randall who would join NASA a few years later ([[:Category:Mars rovers|Mars rovers]] and probes are a frequent topic on ''xkcd'').

====Degrees Fahrenheit====
;0&nbsp;°F to 100&nbsp;°F good match for temperature range in which most humans live
:In the context of air temperature, 0&nbsp;°F and 100&nbsp;°F correspond to "just about as cold as it gets" and "just about as hot as it gets" in temperate zones, thereby making Fahrenheit a useful temperature scale for weather reporting where most people live. By contrast, in Celsius a range of common temperatures in temperate zones is -20&nbsp;°C to 40&nbsp;°C, which is a less intuitive range for those used to the Fahrenheit scale.
;Rounds more usefully (70's, 90's)
:An argument sometimes heard for the continued use of Fahrenheit temperatures is that each 10 degrees change is meaningful in how we feel the temperature. Thus, it is convenient to talk about the temperature being in the 70's today, or in the 90's, etc. Since the Celsius degrees are almost twice as large, a similar statement about the temperature being in the 20's or 30's is not as useful, unless more precision is added by using phrases like low 20's or high 30's. However, this seems likely to be more a matter of which scale you are used to using than anything inherent in one scale or the other.
;Unit-aware computing makes imperial less annoying
:If you need to constantly convert between imperial and SI measurements in your head, or even between different imperial units (e.g., ounces and pounds), it gets annoying and is a strong argument for everyone using metric measurements all the time. But when it is easy to get the temperature - or any other measurement - reported in whatever units you want just by selecting the units you want your computer to report, then the annoyance is minimized, and the arguments for why we should stop using a familiar scale are weakened.  Note that Cueball is looking at his smart-phone to get the current temperature.
:As with many Americans, Randall is treating the {{w|United States customary units|United States customary system}} as identical to the {{w|imperial system}} as previously used in most of the rest of the English speaking world. There have many commonalites, and both systems have temperature measured in degrees Fahrenheit, but also differ in some ways (especially with certain units of volume).
;SI prefixes are less relevant for temperatures
:One of the nice things about SI measurements is how the same basic unit scales by factors of 10 with common prefixes - e.g., kilometer, millimeter, kilogram, milligram, etc.  Imperial measurements don't have this feature - you don't talk about long distances as kiloinches or small weights as millipounds. But, we generally don't use multiple units for atmospheric temperature (millidegrees or kilodegrees), so this argument for using SI measurements for length, mass, volume, etc., isn't as applicable for temperature scales.
;Fahrenheit is likely more clear in this context
:The fact that Cueball is having this conflict at all implies that the conversation is taking place in America, presumably between Americans. Given that, and given that the discussion is about the weather, the typical assumption is that temperatures will be given in Fahrenheit, unless specified otherwise. An answer in Fahrenheit is therefore likely to be easily understood, while an answer in Celsius risks being confusing, or even incomprehensible. 
;Valuing unit standardization over being helpful possibly makes me a bad friend
:The final thing Cueball considers is to question why he would give an answer that attaches more value to promoting standardization of units when all his friend wants to know is whether it is cold or warm outside. Wouldn't it be more friendly to just answer the question the way his friend will find most convenient? This is probably the reason he ends up not giving any real answer, as giving the answer in Celsius would make him a bad friend. Panicking and giving the answer in radians makes him a weird friend, which might or might not be preferable to being a bad friend.

==Transcript==
:[Cueball is looking at his smartphone while a friend calls to him from off-panel. Cueball is thinking as indicated with a thought bubble.]
:Off-screen voice: Hey, what's the temperature outside?
:Cueball (thinking): Should I give it in °F or °C?

:[Zoom in on Cueballs head with a list of reason to use Celsius above him:]
:'''Degrees Celsius'''
:* International standard
:* Helps reduce America's weird isolationism
:* Nice how "negative" means below freezing
:* Physics major loyalty
:* Easier to spell
:* We lost a Mars probe over this crap

:[Same view of Cueballs head, but wider frame to accommodate a broader a list of reason to use Fahrenheit:]
:'''Degrees Fahrenheit'''
:* 0°F to 100°F good match for temperature range in which most humans live
:* Rounds more usefully (70's, 90's)
:* Unit-aware computing makes imperial less annoying
:* SI prefixes are less relevant for temperatures
:* Fahrenheit is likely more clear in this context
:* Valuing unit standardization over being helpful possibly makes me a bad friend

:[Cueball is holding his smartphone down while thinking as indicated with another thought bubble floating at the top. He then speaks and gets a reply from his off-panel friend.]
:Cueball (thinking): Crap, gotta pick something. Uhh...
:Cueball: ...0.173 radians.
:Off-screen voice: I'll just go check myself

==Trivia==
* At -0.698 radians (-40 degrees) it would not have mattered whether it was radians Celsius or radians Fahrenheit as the two scales are equal at this point: -40&nbsp;°F is the same temperature as -40&nbsp;°C.

* The Fahrenheit/Celsius debate was later referenced in [[1923: Felsius]].

* Cueball’s friend’s last sentence does not end in punctuation. 

{{comic discussion}}
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