explain xkcd - User contributions [en]

3013: Kedging Cannon

2024-11-19T04:14:53Z

162.158.91.13: /* Explanation */ cleanup

{{comic
| number = 3013
| date = November 18, 2024
| title = Kedging Cannon
| image = kedging_cannon_2x.png
| imagesize = 740x259px
| noexpand = true
| titletext = The real key was inventing the windmill-powered winch.
}}

==Explanation==
{{incomplete|Created by a HEADCANNON. Do NOT delete this tag too soon.}}

Sailing vessels can navigate upwind through a technique called {{w|Tacking_(sailing)|tacking}} (or "tacking against the wind") which involves zigzagging across the wind's direction. However, this comic describes a fictional scenario where a ship's captain, unfamiliar with tacking, has developed an alternative method based on {{w|kedging}}.

Kedging is a historical maritime technique typically reserved for specific situations where conventional sailing methods are impractical, such as in calm waters, during precise maneuvering, or against strong opposing winds or currents. Traditional kedging involves deploying an anchor from the vessel, either manually or via a smaller boat, and then {{w|winch|winching}} the ship toward the anchor point using ropes or chains. The anchor points often utilize natural features such as trees or reefs. In this comic, the captain has modified this technique by inventing a specialized "kedging cannon" to project the anchor greater distances.

The title text indicates that the captain's system has evolved to incorporate a windmill mechanism that harnesses wind power to draw in the kedging rope, which makes the solution even less efficient, given that wind could be used for tacking.

{{cot|Speed and economic analysis of wind-winched kedging cannons compared to tacking}}
;Analysis of the speed and economics of the following system compared to tacking

A dual-anchor kedging cannon system for sailing upwind, consisting of:
* Two kedging cannons firing 16 kg anchors
* 6-meter diameter windmill powering winch system
* Dual-winch setup for continuous operation
* Operating in 15 knot headwind conditions

;Wind Power Generation
Available wind power is given by:
P = ½ρAv³η
where:
* ρ = 1.225 kg/m³ (air density)
* A = π(D/2)² = 28.3 m² (windmill area)
* v = 7.72 m/s (wind speed)
* η = 0.245 (combined efficiency)

This yields 1.95 kW of usable power.

;Drag Forces
Total drag combines water and air resistance:
F_drag = F_water + F_wind
where:
* F_water = ½ρ_w C_d A_w v²
* F_wind = ½ρ_a C_a A_f v²

Using:
* Water density (ρ_w) = 1025 kg/m³
* Hull drag coefficient (C_d) = 0.04
* Wetted area (A_w) = 40 m²
* Air density (ρ_a) = 1.225 kg/m³
* Air drag coefficient (C_a) = 0.8
* Frontal area (A_f) = 8 m²

Total drag force = 1053.4 N

;Anchor Ballistics
For 300m range with 45° launch angle:
* Required velocity = 54.7 m/s
* Launch energy = 23.7 kJ
* Black powder energy per shot = 680.4 kJ
* Launch efficiency = 3.5%

;System Performance
* Winch speed = 3.60 knots
* Cycle time = 194.7 seconds
* Effective speed = 3.04 knots
* Compared to tacking speed = 4.95 knots
* Speed ratio (Kedging/Tacking) = 0.61

;Economic Analysis
* Shots needed per nautical mile: 6.1
* Black powder cost per shot: $10 (0.5 lbs @ $20/lb)
* Cost per nautical mile: $60.76
* Powder consumption: 9.2 lbs/hour
* Operating cost: $184.90/hour

Example 100nm journey:
* Total powder cost: $6,076.12
* Journey time: 32.9 hours

;Conclusion
The dual-anchor kedging cannon system is both slower and significantly more expensive than traditional tacking:

Speed disadvantage:
* Achieves only 61% of tacking speed
* 100nm journey takes 32.9 hours vs 20.2 hours tacking

Economic disadvantage:
* High powder costs ($60.76 per nautical mile)
* Requires significant powder storage (303 lbs for 100nm journey)
* Additional wear and tear on mechanical systems

Key limiting factors:
* Limited wind power available (1.95 kW from 6m windmill)
* High drag forces (1053.4 N total)
* Poor ballistic efficiency (3.5% of powder energy converts to useful launch)
* Long cycle times due to realistic winching speeds

The system could potentially be improved by:
* Larger windmill (though practical size limits on boats)
* More aerodynamic anchor design
* More efficient powder-to-launch energy conversion
* Reduced transfer time between anchors

Therefore, given both the energy constraints and economic factors, traditional tacking remains far more practical for upwind progress. The key insight is that while the kedging cannon seems to "cheat" the wind by going straight upwind, it actually requires converting wind energy to mechanical work less efficiently than a well-designed sail plan, while also consuming expensive gunpowder. The indirect path of tacking makes better use of the available wind force with no consumable costs.
{{cob}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[A two-masted sailing ship is floating on the sea. Two tiny figures can be seen at the ship's bow.]
:Captain: I hope someday someone invents a way to sail upwind.
:Captain: Using the kedging cannon just wastes so much gunpowder.
:[Close-up on the deck of the ship. Cueball is talking to the ship's captain, who is aiming a cannon containing an anchor. Chains are draped from the cannon.]
:Cueball: The ''what?''
:Cueball: Wait, do you not know how to sail upwind? Is that why your ship takes forever to--
:Captain: Stand by...''FIRE!''
:[Distant shot showing the anchor and its chain being launched out in front of the ship, towards the right of the panel.]
:SFX: BOOM
:[The line becomes taut and the ship is dragged forwards, towards the right of the panel.]
:SFX: Click click click

{{comic discussion}}
[[Category:Comics featuring Cueball]]

3001: Temperature Scales

2024-10-26T22:37:30Z

162.158.91.13: /* Examples */ the linear Newton approximation has issues; most notably that its not linear ughhhh

{{comic
| number = 3001
| date = October 21, 2024
| title = Temperature Scales
| image = temperature_scales_2x.png
| imagesize = 740x535px
| noexpand = true
| titletext = In my new scale, °X, 0 is Earths' record lowest surface temperature, 50 is the global average, and 100 is the record highest, with a linear scale between each point and adjustment every year as needed.
}}

==Explanation==
{{incomplete|Created by an TOTALLY CONFORMING TEMPERATURE SYSTEM. Do NOT delete this tag too soon.}}

Since the invention of the {{w|thermometer}}, a number of different {{w|temperature}} scales have been proposed. In modern times, most of the world uses the 1745 {{w|Celsius}} scale for everyday temperature measurements. A small number of countries (the USA and {{w|Territories of the United States|its territories}}, the Bahamas, Belize, the Cayman Islands, Liberia, and Palau) retain the {{w|Imperial units|imperial system}} (or the related {{w|United States customary units|US customary system}}), which uses the 1724 {{w|Fahrenheit}} scale. The other widely used temperature scale is the 1848 {{w|Kelvin}} scale, which uses the same degrees as Celsius, but is rooted at {{w|absolute zero}}, making it both useful in scientific calculations and easy to convert to and from Celsius (which, along with degrees Fahrenheit, is now defined relative to kelvins.) The Kelvin scale has been part of the widely adopted official {{w|metric system}} since 1954. Even in countries that use Fahrenheit, scientific measurements are usually made in degrees Celsius or kelvins.

The comic compares these scales, and a number of others, on [[Randall]]'s scale of "cursedness." The joke is highlighting how different the temperature scales are, and how impractical most of them are. All of the listed scales (except Randall's new °X scale defined in the title text) are real, but most are obsolete. Please see also [[1923: Felsius]], a combination of degrees Fahrenheit and Celsius.

{| class=wikitable
! scope="col" | Unit
! scope="col" | Water freezes
! scope="col" | Water boils
! scope="col" | Notes
! scope="col" | Cursedness
! scope="col" | Explanation
|-
| {{w|Celsius}} || 0 || 100 || Used in most of the world || 2/10 || The Celsius (°C) scale, also known as "centigrade", was devised by Swedish astronomer {{w|Anders Celsius}} in 1742 and revised in 1745, a year after his death. 0°C represents the freezing point of water and 100°C represents the boiling point, both under {{w|standard atmospheric pressure}}. The Celsius scale is now defined in terms of kelvin. By the given "cursedness," it is regarded as one of the least problematic temperature scales.
|-
| {{w|Kelvin}} || 273.15 || 373.15 || 0K is absolute zero || 2/10 || Kelvins (plural with a lowercase 'k' as a temperature unit, like meters, ohms, watts, and amps; or as the symbol 'K', without the degrees symbol '°', unlike most other such units) are a unit of temperature devised by {{w|Lord Kelvin}} in 1848. They use the same degrees as Celsius but is shifted by 273.15 to set absolute zero at 0K (based on the {{w|Boltzmann constant}}.)
<center>Celsius = kelvin – 273.15.</center>
<center>kelvin = Celsius + 273.15.</center>
While kelvins are very useful for calculations in {{w|thermodynamics}} and material physics, they can be unintuitive to laypersons.
|-
| {{w|Fahrenheit}} || 32 || 212 || Outdoors in most places is between 0–100 || 3/10 || Fahrenheit (°F) is officially used in a few countries and informally in several others. It originated in a time when factors of 360 were favored in science over powers of ten, which is why the freezing and boiling points of water are set 180° apart. Devised around 1724, {{w|Daniel Fahrenheit}} chose not to base 0° on the freezing point of water, instead originally setting it at the coldest temperature he could achieve: the freezing point of an {{w|ammonium chloride}} {{w|brine}} solution.
<center>Celsius = (Fahrenheit – 32) × 5/9.</center>
<center>Fahrenheit = Celsius × 9/5 + 32.</center>
Although those reference points are now considered arbitrary and outdated by modern scholars, the scale gained popularity in Anglophone countries, possibly because everyday weather conditions usually fall handily all across the range 0–100°F. 100°F is {{w|Human body temperature#Historical understanding|close to normal human body temperature}} (the original intent was to set 90°F as exactly this, 90 being a quarter of 360). The Fahrenheit scale remains officially used only in Randall's home country (the U.S., and its territories), the Bahamas, Belize, the Cayman Islands, Liberia and Palau.
|-
| {{w|Réaumur scale|Réaumur}} || 0 || 80 || Like Celsius, but with 80 instead of 100 || 3/8 || Abbreviated as °Ré, this system devised by {{w|René Antoine Ferchault de Réaumur}} in 1730 was used in some places until the early 20th century, mostly for cheese-making.
<center>Celsius = Réaumur / 0.8.</center>
<center>Réaumur = Celsius × 0.8.</center>
The rating (3/8) is a joke on the boiling point of water in this system being 80 instead of 100 as it is in Celsius; converting this to an out-of-ten scale would give 3.75/10, labeling it as more cursed than Fahrenheit but less so than Rømer.
|-
| {{w|Rømer scale|Rømer}} || 7.5 || 60 || Fahrenheit precursor with similarly random design || 4/10 || Abbreviated as °Rø, this scale was created by the Danish astronomer {{w|Ole Rømer}} around 1702. Much like Fahrenheit, it originally used the freezing point of ammonium chloride brine as the benchmark for 0°, and the scale is built with factors of 360 in mind with the boiling point of pure water at 60°. Like the Fahrenheit scale, the freezing point of pure water was not originally considered significant by Rømer, but the scale was later updated to give the value of 7.5 at this point.
<center>Celsius = (Rømer – 7.5) × 40/21.</center>
<center>Rømer = Celsius × 21/40 + 7.5.</center>
The Rømer scale is considered the predecessor of both the Celsius and Fahrenheit scales, because Réaumur was inspired by Rømer's scale, Celsius based his work on Réaumur and Fahrenheit specifically designed his scale with more divisions than Rømer's to reduce the necessity for fractions.
|-
| {{w|Rankine scale|Rankine}} || 491.7 || 671.7 || Fahrenheit, but with 0°F [''sic;'' should be 0°Ra] set to absolute zero || 6/10 || The Rankine scale (°R or °Ra), devised in 1859 by {{w|William Rankine}}, is to Fahrenheit what kelvin is to Celsius, an absolute (rather than a relative) scale. The scale is mostly obsolete, but is still occasionally used in legacy industrial operations where absolute temperature scales are required. It is described as more cursed than the otherwise identical Fahrenheit scale, despite being rooted at a more universal zero point.
<center>Celsius = (Rankine – 491.67) × 5/9.</center>
<center>Rankine = (Celsius + 273.15) × 9/5.</center>
Another comic, [[2292: Thermometer]], expresses disdain for this scale.
|-
| {{w|Newton scale|Newton}} || 0 || 33-ish || Poorly defined, with reference points like "the hottest water you can hold your hand in" || 7-ish/10 || The famous scientist and mathematician {{w|Isaac Newton}} published this scale in 1701, which was referred to by the the °N symbol. Sadly, the degrees of temperature specified do not correlate exactly with amounts of {{w|heat}}. The cursedness rating (7-ish/10) is a joke about the vagueness of the scale's definition. So, as a linear appproximation:
<center>Celsius = Newton × 100/33.</center>
<center>Newton = Celsius × 33/100.</center>
Very few scientists other than Newton ever used this scale,{{Actual citation needed}} but it did appear on commercial thermometers around 1758.[https://www.scienceandsociety.co.uk/results.asp?image=10413117&wwwflag=&imagepos=43]
|-
| {{w|Wedgwood scale|Wedgwood}} || –8 || –6.7 || Intended for comparing the melting points of metals, all of which it was very wrong about || 9/10 || Created by the potter {{w|Josiah Wedgwood}} in 1782, the '°W' scale was based on the shrinking of clay when heated above red heat, but was found to be very inconsistent.
<center>Celsius = (Wedgwood + 8) × 100/1.3.</center>
<center>Wedgwood = (Celsius × 1.3/100) – 8.</center>
The comic has a typo, as the scale is called Wedgwood, without the second 'e'.
|-
| Galen || –4? || 4?? || Runs from –4 (cold) to 4 (hot). 0 is "normal"(?) || 4/–4 || The Greek physician {{w|Galen}} suggested a "neutral" temperature around 180 A.D.,[https://www.loebclassics.com/view/galen-temperaments/2020/pb_LCL546.3.xml] when he was a prominent physician in the {{w|Roman Empire}}. Created by mixing equal parts of boiling water and ice, on either side of this neutral point he described four degrees of heat and four degrees of cold. Assuming his extremes were those points:
<center>Celsius = (Galen × 100 / 8) + 22.</center>
<center>Galen = ((Celsius – 22) / 100) × 8.</center>
This range from +4 to –4 is humorously used as its rating, implying –100% cursedness. Technically this makes it the least cursed of all the listed scales, but the idea of negative cursedness, and cursedness itself, is not clear. There is no standard modern abbreviation for Galen's scale.
|-
| {{w|Celsius#History|''Real'' Celsius}} || 100 || 0 || In Anders Celsius's original 1742 specification, bigger numbers are ''colder''; others later flipped it || 10/0 || Most scales' temperatures can be indefinitely large, but have an absolute minimum temperature. By starting at a maximum value and counting down, this scale is indeed cursed, as nearly all possible temperatures through 1.42×1032K, the maximum attainable physical temperature,[https://doi.org/10.4236/jamp.2024.1210198] will be negative in this implementation. The cursedness rating (10/0) is a joke on the scale "flipping" the fixed points of modern Celsius. Division by zero is strictly undefined (see [[2295: Garbage Math]]) and may be interpreted in a number of counter-intuitive ways.
<center>Celsius = 100 – real_Celsius.</center>
<center>real_Celsius = 100 – Celsius.</center>
The original logic was that zero could be easily calibrated to the height of a {{w|Millimetre of mercury|column of mercury}} at the temperature of boiling water, and further measurements then made of the amount it ''reduced'' in height under cooler conditions. This orientation survives in the historic {{w|Delisle scale}} devised in 1732 by French astronomer {{w|Joseph-Nicolas Delisle}}, which arguably inspired the Celsius scale. The scale originally used by Professor Celsius was changed, to more or less the form already described above, after his death in 1745. Delisle's scale was never reversed.
|-
| [https://physics.stackexchange.com/questions/459851/john-daltons-temperature-scale#459863 Dalton] || 0 || 100 || A nonlinear scale; 0°C and 100°C are 0 and 100 Dalton, but 50°C is 53.9 Dalton || 53.9/50 || {{w|John Dalton}} proposed a logarithmic temperature scale in 1802 during his work on what became {{w|Charles's Law}}. The scale is defined so that absolute zero is at negative infinity, with the exponent chosen to match Celsius at 0 and 100:
<center>Celsius = 273.15 × ''e''(Dalton / 320.55) – 273.15.</center>
<center>Dalton = 320.55 × {{w|Natural logarithm|''ln''(}} (Celsius + 273.15) / 273.15 ).</center>
There is no standard abbreviation for Dalton's scale. While Dalton temperature is defined for all positive and negative numbers, the nonlinear scale is difficult to work with since the amount of heat represented by a change of one degree Dalton is not constant. Degrees Dalton differs from Celsius by as much as 3.9 degrees between 0 and 100, but diverges much more for more extreme temperatures. The rating (53.9/50) is a joke about the unit, as 53.9 Dalton equates to 50 degrees Celsius — i.e., it could be said to be 107.8% (even more than entirely) cursed.
|-
| °X || 42.9 || 151.4 || '''Title text:''' "In my new scale, °X, 0 is Earths' [''sic''] record lowest surface temperature, 50 is the global average, and 100 is the record highest, with a linear scale between each point and adjustment every year as needed." || Randall has not stated the cursedness of his new scale. || The {{w|Lowest temperature recorded on Earth|record lowest surface temperature on Earth}} as of 2024 is –89.2°C (–128.6°F), recorded at the {{w|Vostok Station|Vostok Research Station}} in Antarctica on July 21, 1983.[https://wmo.asu.edu/content/world-lowest-temperature] The average surface temperature as of 2023, the most recent available, is 14.8°C (58.6°F.)[https://climate.copernicus.eu/climate-indicators/temperature] The {{w|Highest temperature recorded on Earth|record highest temperature}} is 56.7°C (134.1°F), recorded on July 10, 1913 at {{w|Furnace Creek, California|Furnace Creek Ranch}} in Death Valley, California.[https://wmo.asu.edu/content/world-highest-temperature]

{{cot|Derivation and graph}}
To break the scale into two linear parts (below and above 14.8°C), we define two separate equations for each range:

1. Below 14.8°C (from –89.2°C to 14.8°C):
* 0 °X corresponds to –89.2°C
* 50 °X corresponds to 14.8°C

We calculate the slope m₁:

<center>m₁ = (50 – 0) / (14.8 – (–89.2)) = 50 / (14.8 + 89.2) = 50 / 104 ≈ 0.48</center>

Now, using the point (14.8°C, 50 °X), we calculate the intercept b₁:

<center>50 = 0.48 × 14.8 + b₁</center>

<center>50 = 7.1 + b₁</center>

<center>b₁ = 50 – 7.1 = 42.9</center>

Thus, the equation for temperatures '''below 14.8°C''' is:

<center>'''X = 0.48 × C + 42.9'''</center>

2. Above 14.8°C (from 14.8°C to 56.7°C):
* 50 °X corresponds to 14.8°C
* 100 °X corresponds to 56.7°C

We calculate the slope m₂:

<center>m₂ = (100 – 50) / (56.7 – 14.8) = 50 / 41.9 ≈ 1.19</center>

Now, using the point (14.8°C, 50 °X), we calculate the intercept b₂:

<center>50 = 1.19 × 14.8 + b₂</center>

<center>50 = 17.6 + b₂</center>

<center>b₂ = 50 – 17.6 = 32.4</center>

Thus, the equation for temperatures '''above 14.8°C''' is:

<center>'''X = 1.19 × C + 32.4'''</center>

;Freezing and boiling points of water

Freezing point of water (0°C): Since 0°C is below 14.8°C, we use the equation X = 0.48 × C + 42.9:

<center>X = 0.48 × 0 + 42.9 = 42.9</center>

So, '''the freezing point is 42.9 °X.'''

Boiling point of water (100°C): Since 100°C is above 14.8°C, we use the equation X = 1.19 × C + 32.4:

<center>X = 1.19 × 100 + 32.4 = 119 + 32.4 = 151.4</center>

So, '''the boiling point is 151.4 °X.'''

[[File:XvsC.png|400px|center]]

See also [[2701: Change in Slope]] for a general discussion of separate linear scales between three points.
{{cob}}
<center>Celsius = (°X – 42.9) / 0.48 if °X < 50; or (°X – 32.4) / 1.19 if °X ≥ 50.</center>
<center>°X = 0.48 × Celsius + 42.9 if Celsius < 14.8; or 1.19 × Celsius + 32.4 if Celsius ≥ 14.8.</center>

Due to high and average temperature records increasing almost every year as a result of {{w|climate change}},[https://www.space.com/last-12-months-broke-temperature-records] Randall's new °X scale must be re-calibrated each year. While such °X values for to everyday temperatures will vary over time, more extreme values like absolute zero or the {{w|Tungsten#Physical properties|melting point of tungsten}} will shift vastly more.

("Surface" temperatures are measured 1.5 meters above ground inside a shaded shelter, to accurately represent air temperature, because measurements closer to the ground are usually quite different due to sunlight, {{w|albedo}}, and the thermal capacity of soil.)
|}

[[File:Temperature Scales.png|center|600px]]

===Examples===

Here are some various temperatures in the above scales:

{| class=wikitable style="text-align: center;"
! Unit scale
! Typical {{w|room temperature}}
! {{w|Properties of water#Melting point|Freezing point of water}}
! {{w|Boiling point#Boiling point of water with elevation|Boiling point of water}}
! Midrange {{w|human body temperature|human body core temperature}}
! Recommended {{w|Refrigerator#Temperature zones and ratings|refrigerator temperature}}[https://www.realsimple.com/food-recipes/shopping-storing/food/refrigerator-temperature]
! Recommended {{w|Refrigerator#Freezer|freezer temperature}}[https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/freezing-and-food-safety]
! Typical warm bath temperature[https://www.kohlerwalkinbath.com/blog/everything-you-need-to-know-about-the-ideal-bath-temperature/]
! Typical {{w|Coffee#Brewing|hot coffee}} temperature
|-
| Celsius || 22 °C || 0 °C || 100 °C || 37 °C || 2.5 °C || –18 °C || 39 °C || 77 °C
|-
| Kelvin || 295 K || 273 K || 373 K || 310 K || 276 K || 255 K || 312 K || 350 K
|-
| Fahrenheit || 72 °F || 32 °F || 212 °F || 98.6 °F || 36.5 °F || 0 °F || 102 °F || 171 °F
|-
| Réaumur || 17.6 °Ré || 0 °Ré || 80 °Ré || 29.6 °Ré || 2 °Ré || –14.4 °Ré || 31.2 °Ré || 61.6 °Ré
|-
| Rømer || 19.1 °Rø || 7.5 °Rø || 60 °Rø || 26.9 °Rø || 8.8 °Rø || –2 °Rø || 28 °Rø || 47.9 °Rø
|-
| Rankine || 531 °Ra || 492 °Ra || 672 °Ra || 558 °Ra || 496 °Ra || 459 °Ra || 562 °Ra || 630 °Ra
|-
| Newton || 7.3 °N || 0 °N || 34 °N[https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/meteorology/early-thermometers-and-temperature-scales] || 12 °N || 0.8 °N || –5.9 °N || 12.9 °N || 25.4 °N
|-
| Wedgwood || –7.71 °W || –8 °W || –6.7 °W || –7.52 °W || –7.97 °W || –8.23 °W || –7.49 °W || –7 °W
|-
| Galen || 0 || –1.76 || 6.24 || 1.2 || –1.56 || –3.2 || 1.36 || 4.4
|-
| ''Real'' Celsius || 78 || 100 || 0 || 63 || 98 || 118 || 61 || 23
|-
| Dalton || 24.8 || 0 || 100 || 40.7 || 2.9 || –21.9 || 42.8 || 79.6
|-
| °X || 59 °X || 43 °X || 151 °X || 76.4 °X || 44.1 °X || 34.3 °X || 78.8 °X || 124 °X
|-
| Felsius || 47 || 16 || 156 || 67.8 || 19.5 || –9.2 || 70.6 || 123.8
|}

Here are the conversion formulas for the [[1923: Felsius|Felsius scale from comic 1923]]:
<center>Celsius = (Felsius − 16) / 1.4.</center>
<center>Felsius = Celsius * 7/5 + 16.</center>

==Transcript==

:Temperature Scales

:[A table with five columns, labelled: Unit, water freezing point, water boiling point, notes, cursedness. There are eleven rows below the labels.]

:[Row 1:] Celsius, 0, 100, Used in most of the world, 2/10
:[Row 2:] Kelvin, 273.15, 373.15, 0K is absolute zero, 2/10
:[Row 3:] Fahrenheit, 32, 212, Outdoors in most places is between 0–100, 3/10
:[Row 4:] Réaumur, 0, 80, Like Celsius, but with 80 instead of 100, 3/8
:[Row 5:] Rømer, 7.5, 60, Fahrenheit precursor with similarly random design, 4/10,
:[Row 6:] Rankine, 491.7, 671.7, Fahrenheit, but with 0°F set to absolute zero, 6/10
:[Row 7:] Newton, 0, 33-ish, Poorly defined, with reference points like "the hottest water you can hold your hand in", 7-ish/10
:[Row 8:] Wedgewood, –8, –6.7, Intended for comparing the melting points of metals, all of which it was very wrong about, 9/10
:[Row 9:] Galen, –4?, 4??, Runs from –4 (cold) to 4 (hot). 0 is "normal"(?), 4/–4
:[Row 10:] ''Real'' Celsius, 100, 0, In Anders Celsius's original specification, bigger numbers are ''colder''; others later flipped it, 10/0
:[Row 11:] Dalton, 0, 100, A nonlinear scale; 0°C and 100°C are 0 and 100 Dalton, but 50°C is 53.9 Dalton, 53.9/50

{{comic discussion}}

[[Category:Charts]]
[[Category:Math]]
[[Category:Physics]]
[[Category:Science]]

3001: Temperature Scales

2024-10-24T07:31:09Z

162.158.91.13: /* Explanation */ s/version/scale

{{comic
| number = 3001
| date = October 21, 2024
| title = Temperature Scales
| image = temperature_scales_2x.png
| imagesize = 740x535px
| noexpand = true
| titletext = In my new scale, °X, 0 is Earths' record lowest surface temperature, 50 is the global average, and 100 is the record highest, with a linear scale between each point and adjustment every year as needed.
}}

==Explanation==
{{incomplete|Created by an EXPONENTIAL TEMPERATURE SYSTEM. Do NOT delete this tag too soon.}}

Since the invention of the {{w|thermometer}}, a number of different {{w|temperature}} scales have been proposed. In modern times, most of the world uses {{w|Celsius}} for everyday temperature measurements. A small number of countries (the USA and {{w|Territories of the United States|its territories}}, the Bahamas, Belize, the Cayman Islands, Liberia, and Palau) retain the {{w|Imperial units|imperial system}}, which uses the {{w|Fahrenheit}} scale, which preceded Celsius by just under two decades. The other widely used temperature scale is {{w|kelvin}}s, which uses the same scale as Celsius, but is rooted at {{w|absolute zero}}, making it both useful in scientific calculations and easy to convert to and from Celsius (which, along with Fahrenheit, is now officially defined relative to kelvins.) Kelvins are part of the {{w|metric system}} that has been widely adopted for official use. Even in countries that use Fahrenheit, scientific measurements are usually done in Celsius or kelvins.

The comic compares these scales, and a number of others, on [[Randall]]'s scale of "cursedness." The joke is highlighting how different the temperature scales are, and how impractical most of them are. All of the listed scales are real, but may be considered obsolete to varying degrees. Please see also [[1923: Felsius]], a combination of Fahrenheit and Celsius.

{| class=wikitable
! scope="col" | Unit
! scope="col" | Water Freezes
! scope="col" | Water Boils
! scope="col" | Notes
! scope="col" | Cursedness
! scope="col" | Explanation
|-
| {{w|Celsius}} || 0 || 100 || Used in most of the world || 2/10 || The Celsius scale was devised by Swedish astronomer {{w|Anders Celsius}} in 1742. 0°C represents the freezing point of water, and 100°C represents the boiling point, both under {{w|standard atmospheric pressure}}. The Celsius scale is now defined in terms of the Kelvin scale. By the given "cursedness," it is regarded as one of the two least problematic temperature scales.
|-
| {{w|Kelvin}} || 273.15 || 373.15 || 0K is absolute zero || 2/10 || Kelvin (written with a lowercase 'k' as a unit, or as 'K', without the degrees symbol '°') is a unit of temperature created by {{w|Lord Kelvin}}. It uses the same scale as Celsius but is shifted by 273.15 to set absolute zero at 0K (based on the {{w|Boltzmann constant}}.) While kelvins are very useful for {{w|thermodynamics}} and material physics, it can be unintuitive. Kelvin and Celsius are the most commonly used units in scientific measurements and calculations.
|-
| {{w|Fahrenheit}} || 32 || 212 || Outdoors in most places is between 0–100 || 3/10 || Fahrenheit (°F) is officially used in a few countries and informally in several others. It originated in a time when factors of 360 were favored in science over powers of ten, which is why the freezing and boiling points of water are set 180° apart. Devised around 1724, {{w|Daniel Fahrenheit}} chose not to base 0° on the freezing point of water, instead setting it at the coldest temperature he could achieve: the freezing point of an {{w|ammonium chloride}} {{w|brine}} solution. Although these reference points are now considered arbitrary and outdated by modern scholars, the scale gained popularity especially in Anglophone countries, likely because it aligns with everyday weather conditions and is intuitively useful. Its range covers typical temperatures across various latitudes and seasons, and 100°F is close to normal human body temperature. The Fahrenheit scale remains commonly used only in the U.S. (Randall's home country), the Bahamas, Belize, the Cayman Islands, Liberia, and Palau.
|-
| {{w|Réaumur scale|Réaumur}} || 0 || 80 || Like Celsius, but with 80 instead of 100 || 3/8 || Abbreviated as °Ré, this system devised by {{w|René Antoine Ferchault de Réaumur}} in 1730 was used in some places until the early 20th century, mostly for cheese-making. The rating (3/8) is a joke on the boiling point of water in this system being 80 instead of 100 as it is in Celsius; converting this to an out-of-ten scale would give 3.75/10, labeling it as more cursed than Fahrenheit but less so than Rømer.
|-
| {{w|Rømer scale|Rømer}} || 7.5 || 60 || Fahrenheit precursor with similarly random design || 4/10 || Abbreviated as °Rø, this scale was created by the Danish astronomer {{w|Ole Rømer}} around 1702. Much like Fahrenheit, it uses the freezing point of ammonium chloride brine as the benchmark for 0°, and the scale is built with factors of 360 in mind with the boiling point of pure water at 60°. Like the Fahrenheit scale, the freezing point of pure water was not originally considered significant by Rømer, but the scale was later updated to fix it to 7.5.
|-
| {{w|Rankine scale|Rankine}} || 491.7 || 671.7 || Fahrenheit, but with 0°F [''sic;'' should be 0°R] set to absolute zero || 6/10 || As the chart mentions, Rankine (°Ra) is to Fahrenheit what kelvin is to Celsius, an absolute scale rather than a relative one. The scale is mostly obsolete, but is still occasionally used in legacy industrial operations where absolute temperature scales are required. It is described as more cursed than the otherwise identical Fahrenheit scale, despite being rooted at a more practical zero-point. Another comic, [[2292: Thermometer]] expresses disdain for this scale.
|-
| {{w|Newton scale|Newton}} || 0 || 33-ish || Poorly defined, with reference points like "the hottest water you can hold your hand in" || 7-ish/10 || The famous scientist and mathematician {{w|Isacc Newton}} published this scale in 1701, which was referred to by the the °N symbol. Sadly, the degrees of temperature specified do not correlate exactly with amounts of {{w|heat}}. The cursedness rating (7-ish/10) is a joke about the vagueness of the scale's definition. Very few scientists other than Newton ever used this scale,{{cn}} but it did appear on commercial thermometers around 1758.[https://www.scienceandsociety.co.uk/results.asp?image=10413117&wwwflag=&imagepos=43]
|-
| {{w|Wedgwood scale|Wedgwood}} || –8 || –6.7 || Intended for comparing the melting points of metals, all of which it was very wrong about || 9/10 || Created by potter {{w|Josiah Wedgwood}} in 1782, the "°W" scale was based on the shrinking of clay when heated above red heat, but was found to be very inaccurate. The comic has a typo, as the scale is called Wedgwood, without the second 'e'.
|-
| Galen || –4? || 4?? || Runs from –4 (cold) to 4 (hot). 0 is "normal"(?) || 4/–4 || The ancient Green physician {{w|Galen}} suggested a "neutral" temperature, created by mixing equal parts of boiling water and ice. On either side of this neutral point, he described four degrees of heat and four degrees of cold. This range from +4 to –4 is humorously described as implying –100% cursedness, which while technically the least cursed of all, is still as unclear as the idea of negative cursedness and cursedness itself. There is no standard abbreviation for Galen's scale.
|-
| {{w|Celsius#History|''Real'' Celsius}} || 100 || 0 || In Anders Celsius's original specification, bigger numbers are ''colder''; others later flipped it || 10/0 || Most scales' temperatures can be indefinitely large, but have an absolute minimum temperature. By starting at a maximum value and counting down, this scale is indeed cursed, as nearly all possible temperatures (through 1.42x1032K, the maximum physical temperature[https://doi.org/10.4236/jamp.2024.1210198]) will be negative. The rating (10/0) is a joke on the scale "flipping" the fixed points of modern Celsius. Division by zero is strictly undefined.
The original logic was that zero could be easily calibrated to the height of a column of mercury at the temperature of boiling water, and further measurements then made of the amount it ''reduced'' in height under cooler conditions. This orientation survives in the historic {{w|Delisle scale}}, which predates (and arguably helped inspire) the Celsius scale. The scale originally used by Professor Celsius was only corrected posthumously, but Delisle's scale was not.
|-
| [https://physics.stackexchange.com/questions/459851/john-daltons-temperature-scale#459863 Dalton] || 0 || 100 || A nonlinear scale; 0°C and 100°C are 0 and 100 Dalton, but 50°C is 53.9 Dalton || 53.9/50 || {{w|John Dalton}} proposed a logarithmic temperature scale. The scale is defined so that absolute zero is at negative infinity, with the exponent chosen to match Celsius at 0 and 100. While Dalton temperature is defined for all positive and negative numbers, the nonlinear scale is difficult to work with since the amount of heat represented by a change of one degree Dalton is not constant. Degrees Dalton differs from Celsius by as much as 3.9 degrees between 0 and 100, but diverges much more for more extreme temperatures.

The rating (53.9/50) is a joke about the unit, as 53.9 Dalton would be 50 degrees Celsius — i.e. the cursedness could be understood as 50/50 (or 10/10, entirely cursed), but perhaps instead as 107.8% (even more than entirely cursed).
|-
| °X || 42.9 || 151.4 || '''Title text:''' "In my new scale, °X, 0 is Earths' [sic] record lowest surface temperature, 50 is the global average, and 100 is the record highest, with a linear scale between each point and adjustment every year as needed." || ''not provided'' || The {{w|Lowest temperature recorded on Earth|record lowest surface temperature on Earth}} as of 2024 is –89.2°C (–128.6°F), recorded at the {{w|Vostok Station|Vostok Research Station}} in Antarctica on July 21, 1983.[https://wmo.asu.edu/content/world-lowest-temperature] The average surface temperature as of 2023, the most recent available, is 14.8°C (58.6°F.)[https://climate.copernicus.eu/climate-indicators/temperature] The {{w|Highest temperature recorded on Earth|record highest temperature}} is 56.7°C (134.1°F), recorded on July 10, 1913 at {{w|Furnace Creek, California|Furnace Creek Ranch}} in Death Valley, California.[https://wmo.asu.edu/content/world-highest-temperature] "Surface" temperatures are measured at 1.5 meters above ground inside a shaded shelter, to accurately represent the temperature of the air, because temperatures closer to the ground are often much different.

{{cot|Derivation and graph}}
To break the scale into two linear parts (below and above 14.8°C), we define two separate equations for each range:

1. Below 14.8°C (from –89.2°C to 14.8°C):
* 0 °X corresponds to –89.2°C
* 50 °X corresponds to 14.8°C

We calculate the slope m₁:

<center>m₁ = (50 – 0) / (14.8 – (–89.2)) = 50 / (14.8 + 89.2) = 50 / 104 ≈ 0.48</center>

Now, using the point (14.8°C, 50 °X), we calculate the intercept b₁:

<center>50 = 0.48 × 14.8 + b₁</center>

<center>50 = 7.1 + b₁</center>

<center>b₁ = 50 – 7.1 = 42.9</center>

Thus, the equation for temperatures '''below 14.8°C''' is:

<center>'''X = 0.48 × C + 42.9'''</center>

2. Above 14.8°C (from 14.8°C to 56.7°C):
* 50 °X corresponds to 14.8°C
* 100 °X corresponds to 56.7°C

We calculate the slope m₂:

<center>m₂ = (100 – 50) / (56.7 – 14.8) = 50 / 41.9 ≈ 1.19</center>

Now, using the point (14.8°C, 50 °X), we calculate the intercept b₂:

<center>50 = 1.19 × 14.8 + b₂</center>

<center>50 = 17.6 + b₂</center>

<center>b₂ = 50 – 17.6 = 32.4</center>

Thus, the equation for temperatures '''above 14.8°C''' is:

<center>'''X = 1.19 × C + 32.4'''</center>

;Freezing and Boiling Points

Freezing point of water (0°C): Since 0°C is below 14.8°C, we use the equation X = 0.48 × C + 42.9:

<center>X = 0.48 × 0 + 42.9 = 42.9</center>

So, the freezing point is 42.9 °X.

Boiling point of water (100°C): Since 100°C is above 14.8°C, we use the equation X = 1.19 × C + 32.4:

<center>X = 1.19 × 100 + 32.4 = 119 + 32.4 = 151.4</center>

So, the boiling point is 151.4 °X.

[[File:XvsC.png|400px|center]]

See also [[2701: Change in Slope]] for a general discussion of separate linear scales between three points.
{{cob}}
Due to high and average temperature records now being broken nearly every year as a result of {{w|climate change}}, Randall's new °X scale must be re-calibrated each year. While extreme values like absolute zero or the {{w|Tungsten#Physical properties|melting point of tungsten}} will shift more significantly over time, everyday temperatures will vary less.
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:Temperature Scales

:[A table with five columns, labelled: Unit, water freezing point, water boiling point, notes, cursedness. There are eleven rows below the labels.]

:[Row 1:] Celsius, 0, 100, Used in most of the world, 2/10
:[Row 2:] Kelvin, 273.15, 373.15, 0K is absolute zero, 2/10
:[Row 3:] Fahrenheit, 32, 212, Outdoors in most places is between 0–100, 3/10
:[Row 4:] Réaumur, 0, 80, Like Celsius, but with 80 instead of 100, 3/8
:[Row 5:] Rømer, 7.5, 60, Fahrenheit precursor with similarly random design, 4/10,
:[Row 6:] Rankine, 491.7, 671.7, Fahrenheit, but with 0°F set to absolute zero, 6/10
:[Row 7:] Newton, 0, 33-ish, Poorly defined, with reference points like "the hottest water you can hold your hand in", 7-ish/10
:[Row 8:] Wedgewood, –8, –6.7, Intended for comparing the melting points of metals, all of which it was very wrong about, 9/10
:[Row 9:] Galen, –4?, 4??, Runs from –4 (cold) to 4 (hot). 0 is "normal"(?), 4/–4
:[Row 10:] ''Real'' Celsius, 100, 0, In Anders Celsius's original specification, bigger numbers are ''colder''; others later flipped it, 10/0
:[Row 11:] Dalton, 0, 100, A nonlinear scale; 0°C and 100°C are 0 and 100 Dalton, but 50°C is 53.9 Dalton, 53.9/50

{{comic discussion}}

[[Category:Charts]]
[[Category:Science]]

2967: Matter

2024-08-03T06:44:23Z

162.158.91.13: /* Explanation */ skaters are not always skateboarders

{{comic
| number = 2967
| date = August 2, 2024
| title = Matter
| image = matter_2x.png
| imagesize = 234x341px
| noexpand = true
| titletext = He was the first person to land a 900, which is especially impressive because pulling off a half-integer spin requires obeying Fermi-Dirac statistics.
}}

==Explanation==
{{incomplete|Created by a GOOFY FRONTSIDE WIKI GRIND TO SECRET PHYSICS DEMO TAPE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In {{w|skateboarding}}, the term 'goofy' means to push with the left foot, using the {{w|Footedness#Goofy_stance|opposite stance}} to standard footing, a stance pushing with one's right foot. The comic uses this as a analogy for {{w|antimatter}} in particle physics, which exhibits the opposite charge to ordinary matter and will destroy both upon collision, releasing energy proportional to their combined mass in a process called annihilation. {{w|Tony Hawk}}, a professional skateboarder of great renown, has apparently obtained a professorship and is teaching this very non-standard theory. Professor Hawk's appearance could be a play on the name of {{w|Stephen Hawking}}, a famous astrophysicist and professor at the University of Cambridge before his death in 2018. As Tony Hawk does not have a degree in physics,{{citation needed}} teaching inaccurate lessons would be a likely pitfall of his professorship.

This analogy also indirectly raises the problem of {{w|baryon asymmetry}}, in which ordinary matter appears to be much more common than antimatter, unlike most distributions of handedness,{{citation needed}} chemical {{w|chirality}}, or the {{w|skewness}} of {{w|Multimodal_distribution|bimodal statistics}} describing asymmetries in nature (called {{w|homochirality}}, e.g., organ shape and centering, or plants favoring one branch over the other at a fork) and in artificial methods, because 'goofy-footed' skateboarders are about common as 'regular-footed'.

The title text describes Hawk as the first person to "land a 900," meaning the successful completion of a {{w|900 (skateboarding)|skateboarding trick}} involving two and a half rotations, or nine hundred degrees (2.5 × 360° = 900°). In physics, {{w|Spin (physics)|spin}} is a {{w|quantum number}} describing subatomic particles, named for the analogous ''but crucially distinct'' concept of {{w|angular momentum}} in classical physics. Obeying {{w|Fermi–Dirac statistics}} requires that the particles involved are {{w|fermion}}s, which include all of the electrons, protons, and neutrons comprising the entirety of Hawk's mass and electrochemical state. Fermions all have {{w|half-integer}} (i.e., ...–1½, –½, ½, 1½...) {{w|spin quantum number}}s which do indeed include 2½. However, it's very important to remember that [https://www.youtube.com/watch?v=pYeRS5a3HbE&ab_channel=ScienceClicEnglish quantum mechanical spin is ''not'' rotation, but how quickly the corresponding particle changes state when rotated.]

While everyone and most everything we ordinarily interact with except light, cosmic rays, and their decay products are comprised entirely of fermions, {{w|Boson#Composite_bosons|any composite particle made of an even number of fermions, including entire atoms and their nuclei, are not fermions}} but {{w|boson}}s, which do ''not'' obey Fermi–Dirac statistics. Luckily, landing a 900 does not actually require complete obedience to Fermi–Dirac statistics, because a skateboarder comprised entirely of bosonic atoms would still have fermionic electrons in the orbitals of those atoms, and thus would still obey the far more macroscopically fundamental {{w|Pauli exclusion principle}}, which gives mostly empty atoms the property of substance, allowing you to hold things, walk, make sound waves with your voice, employ any mechanical property of matter, and allowing a sufficiently skilled skateboarder to land a 900.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Tony Hawk (drawn with short hair) gesturing at a narrow whiteboard on which illegible things are marked, what may be a Feynman diagram with one of the particle/antiparticle pair going into a circle (possibly representing a black hole, and thus depicting the popularized(incorrect) analogy for {{w|Hawking radiation}}), and at the bottom, a 2x3 table of values.]
:Tony Hawk: In the standard model, regular matter will annihilate if it comes in contact with oppositely-charged ''goofy'' matter.

:[Caption below the panel:]
:Tony Hawk becomes a physics professor

{{comic discussion}}

[[Category:Comics featuring real people]]
[[Category:Physics]]
[[Category:Statistics]]

2962: President Venn Diagram

2024-07-23T01:56:58Z

162.158.91.13: /* Explanation */ source

{{comic
| number = 2962
| date = July 22, 2024
| title = President Venn Diagram
| image = president_venn_diagram_2x.png
| imagesize = 445x398px
| noexpand = true
| titletext = Hard to imagine political rhetoric more microtargeted at me than 'I love Venn diagrams. I really do, I love Venn diagrams. It's just something about those three circles.'
}}

==Explanation==
{{incomplete|Created by 2,382,203 Massachusetts write-in ballots for Randall Munroe - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic features a three-way {{w|Venn diagram}}. The three circles represent eligibility for US presidency, qualification for US presidency, and love for Venn diagrams. According to Article II of the {{w|U.S. Constitution}}, someone is {{w|President_of_the_United_States#Eligibility|eligible for the presidency}} if they are a natural-born citizen of the United States, are at least 35 years old, and are a resident in the United States for at least 14 years.

Randall is known for his love of Venn diagrams, which feature heavily on xkcd. In this comic he implies that one reason why he is likely to support {{w|Kamala Harris}} for president is her alleged love of Venn diagrams, which she shares with Randall (who claims to be eligible for president but not qualified to be a good president).

Current Vice President Kamala Harris is the likely Democratic party nominee for the 2024 election, following current President {{w|Joe Biden}}'s ending of his campaign the day before this comic's release. Kamala's love for Venn diagrams is something of a meme, and has been used by her in her campaign [https://www.independent.co.uk/news/world/americas/us-politics/kamala-harris-campaign-memes-gen-z-b2583802.html]

The title text [https://www.youtube.com/watch?v=eWR2uTfrh-k quotes Kamala Harris on her affection for Venn diagrams,] and implies that the best way to target Randall with political ads is to mention how amazing Venn diagrams are.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
A Venn diagram with three circles. 
Upper left circle: "Eligible to be President" 
Upper right circle: "Would be a good President" 
Lower circle: "Unusually vocal about love of Venn diagrams" 
Intersection of all three circles: "Kamala Harris" 
Intersection of the upper left and lower circles: "Me"

{{comic discussion}}
[[Category: Venn diagrams]]
[[Category: Politics]]
[[Category: Elections]]
[[Category: Comics featuring politicians]]

2318: Dynamic Entropy

2024-05-31T06:13:21Z

162.158.91.13: /* Explanation */ typo

{{comic
| number = 2318
| date = June 10, 2020
| title = Dynamic Entropy
| image = dynamic_entropy.png
| titletext = Despite years of effort by my physics professors to normalize it, deep down I remain convinced that 'dynamical' is not really a word.
}}

==Explanation==
This is another one of [[Randall|Randall's]] [[:Category:Tips|Tips]], this time a [[:Category:Science tip|Science Tip]]. This time it is a bit special since it came less than three weeks after another Science Tip: [[2311: Confidence Interval]] (which was itself the first time that a non-Protip Tip type has been re-used). This is the first time a type of tip (that was not a [[:Category:Protip|Protip]]) has been used for two "tips comics" in a row.

This Science Tip suggests that if you have a cool new concept, you should call it ''dynamic entropy''.

{{w|Dynamic programming}} is a mathematical optimization method and computer programming method developed by {{w|Richard Bellman}} in the 1950s. The {{w|Dynamic programming#History|History section}} of the Wikipedia article contains the full paragraph from Bellman's autobiography that contains the quote that is in the comic strip. Bellman describes how he was doing mathematical research funded by the military at a time when the Secretary of Defense had a literal pathological fear of the word "research", and by extension, "mathematical". Bellman borrowed the word "dynamic" from physics as being both accurate for his work and as a word that in plain English has positive connotations and is never used in a pejorative sense (expressing contempt or disapproval). The word "dynamic" itself comes from the Greek ''dynamikos'', "powerful", which is a positive meaning in itself, and has been applied to topics in physics that are related to motion and forces and used in ordinary English to refer to things that exert power, force, growth, and change (dynamo, dynamite, and as an adjective). Even though those things aren't always good, when they're bad, we use other words instead (e.g. cancer undergoes {{w|metastasis}}, not "dynamism").

{{w|Entropy}} is a term from physics, specifically statistical mechanics, describing a property of a thermodynamic system. When {{w|Claude Shannon}} developed a mathematical framework for studying signal processing and communications systems, which became known as {{w|Information theory}}, he struggled to come up with a proper name for one mathematical concept in his theory that quantified amount of noise or uncertainty in a signal. Computer scientist {{w|John von Neumann}} noticed the similarity of the equations with some in thermodynamics and suggested, "You should {{w|Entropy (information theory)|call it entropy}}, for two reasons. In the first place your uncertainty function has been used in statistical mechanics under that name, so it already has a name. In the second place, and more important, no one really knows what entropy really is, so in a debate you will always have the advantage." (see {{w|History of information theory#Entropy in statistical mechanics|History of information theory}}). The following is an excerpt from the explanation of [[1862: Particle Properties]]:

<blockquote>
The term "entropy", which {{w|History of entropy|began}} as a {{w|Entropy (classical thermodynamics)|thermodynamic measure}}, has since been adopted {{w|Entropy in thermodynamics and information theory|by analogy}} into {{w|Entropy (disambiguation)|multiple seemingly unrelated domains}} including, for example, information theory. The table allows that the term "entropy" must mean something in the context of particle physics, but isn't certain whether it's the classical, Gibbs' modern {{w|Entropy (statistical thermodynamics)|statistical mechanics}}, Von Neumann's {{w|Von Neumann entropy|quantum entropy}}, or some other meaning.

In classical thermodynamics, entropy is a macroscopic property describing the disorder or randomness of a system with many particles. However, in statistical mechanics and quantum mechanics, the concept of entropy can also be applied to single particles under certain conditions. If the particle's position is not precisely known and can be described by a probability distribution, this contributes to entropy. Similarly, if the particle's momentum is uncertain and described probabilistically, this also contributes to entropy. A single quantum particle in a pure state (e.g., an electron in a specific atomic orbital) has zero entropy. This is because there is no uncertainty about the state of the system. If the single particle's state is described by a density matrix representing a mixed state (a probabilistic mixture of several possible states), the Von Neumann entropy can quantify the degree of uncertainty or mixedness of the state.

Imagine two identical balloons filled with the same gas and heated from two opposite sides with identical heat sources, creating symmetric temperature gradients in both; because the distribution of temperatures is the same, the Gibbs statistical thermodynamic entropy 𝑆 of the gas molecule particles in each balloon will be the same. In contrast, if one balloon is heated by a low-power heat source and another by an otherwise identical high-power heat source, the balloon next to the high-power heat source will have a steeper temperature gradient, increasing the number of [https://www.sciencedirect.com/topics/mathematics/accessible-microstates accessible] {{w|Microstate|microstates}}, so the Gibbs entropy 𝑆low_power < 𝑆high_power. Now consider electrons in two atoms excited by absorbing identical photons to a mixed state; if the mixed states have the same probabilities for different energy levels, their Von Neumann quantum entropy 𝑆 values will be the same. Conversely, if one atom has electrons excited to a {{w|Purity_(quantum_mechanics)|pure state}} and another to a mixed state by photons of different energies, the mixed state will have higher entropy due to greater uncertainty, i.e., 𝑆pure = 0 and 0 < 𝑆mixed ≤ ln(2).
</blockquote>

The naming of dynamic programming and of entropy in information theory are both examples of scientists choosing a name for what were at least partially very non-scientific seeming reasons. In one case because it has only positive and no negative connotations in plain English. In the other case because there is much confusion over the meaning of the word so Shannon would be free to adopt it in a new context. [[Randall]] is claiming that would make them great to put together to name some new concept; the combination will mean whatever the creator wants it to mean (even able to change mid-debate), and never sound bad the way that e.g. {{w|cold fusion}} has come to be.

Even though the caption implies that "dynamic entropy" would be available as a new name, it has actually been used in physics<ref>Allegrini, P., Douglas, J. F., & Glotzer, S. C. (1999). Dynamic entropy as a measure of caging and persistent particle motion in supercooled liquids. Physical Review E, 60(5), 5714, doi: 10.1103/physreve.60.5714.</ref>, probability<ref>Asadi, M., Ebrahimi, N., Hamedani, G., & Soofi, E. (2004). Maximum Dynamic Entropy Models. Journal of Applied Probability, 41(2), 379-390. Retrieved June 11, 2020, from www.jstor.org/stable/3216023</ref>, computer science<ref>S. Satpathy et al., "An All-Digital Unified Static/Dynamic Entropy Generator Featuring Self-Calibrating Hierarchical Von Neumann Extraction for Secure Privacy-Preserving Mutual Authentication in IoT Mote Platforms," 2018 IEEE Symposium on VLSI Circuits, Honolulu, HI, 2018, pp. 169-170, doi: 10.1109/VLSIC.2018.8502369.</ref>, and even the term "dynamical entropy" in physics<ref>Green, J. R., Costa, A. B., Grzybowski, B. A., & Szleifer, I. (2013). Relationship between dynamical entropy and energy dissipation far from thermodynamic equilibrium. Proceedings of the National Academy of Sciences, 110(41), 16339-16343.</ref><ref>Słomczyński, W., & Szczepanek, A. (2017). Quantum dynamical entropy, chaotic unitaries and complex Hadamard matrices. IEEE Transactions on Information Theory, 63(12), 7821-7831, doi: 10.1109/TIT.2017.2751507.</ref> and bioscience<ref>Chakrabarti, C. G., & Ghosh, K. (2013). Dynamical entropy via entropy of non-random matrices: Application to stability and complexity in modelling ecosystems. Mathematical biosciences, 245(2), 278-281, doi: 10.1016/j.mbs.2013.07.016.</ref>.

In the title text Randall mentions that, even though his physics professors have continued to use the word "dynamical", "trying to normalize it" by repetitive usage, he remains convinced that it is not really a word. Presumably he doesn't like that it has two suffixes used to make words into adjectives, -ic and -al, as if "dynamic" wasn't already positive enough. The [https://www.thefreedictionary.com/Commonly-Confused-Suffixes-ic-vs-ical.htm#:~:text=Words%20ending%20in%20%E2%80%9C%2Dic%E2%80%9D,are%20notoriously%20difficult%20to%20distinguish Free Dictionary] discusses how -ic and -ical suffixes are confused in many common words and explains their different uses.

The term "dynamical" in physics generally is used in "{{w|Dynamical system}}" or as an adjective to name a concept as applied to dynamical systems such as "dynamical entropy"<ref>Atmanspacher, H. (1997) "Dynamical entropy in dynamical systems," in ''Time, temporality, now'' (pp. 327-346). Springer, Berlin, Heidelberg, doi: 10.1007/978-3-642-60707-3_22</ref>.

==Transcript==
:[One panel only with text and a few lines and arrows. There are two columns each with a heading. Beneath each heading is a quote written on four lines. Below the quote, in grey font, and indented, starting with a hyphen, with the text aligned to the right of this are five lines of text. This explains who the quote belongs to and where it was stated (in brackets at the end). From the bottom of each of these two gray text paragraphs gray curved arrows goes down to two gray lines. Below each of these two lines are one large word per line. They are again in black text.]
:<big>Dynamic</big>
:"It's impossible to use the word 'dynamic' in the pejorative sense... Thus, I thought 'Dynamic Programming' was a good name."
::- Richard Bellman, explaining how he picked a name for his math research to try to protect it from criticism (''Eye of the Hurricane'', 1984)

:<big>Entropy</big>
:"You should call it 'Entropy'... No one knows what entropy really is, so in a debate you will always have the advantage."
::- John von Neumann, to Claude Shannon, on why he should borrow the physics term in information theory (as told to Myron Tribus)

:::<big><big>'''''Dynamic Entropy'''''</big></big>

:[Caption below the panel:]
:Science Tip: If you have a cool concept you need a name for, try "Dynamic Entropy."

== Trivia ==

Many of {{w|Buckminster Fuller}}'s designs and works were associated with the word "{{w|dymaxion}}", a combination of the words "dynamic", "maximum", and "tension", all words that Fuller himself used a lot in talking about his work, and which are words that simultaneously have use in science and positive connotations in lay English.

==References==
<references />

{{comic discussion}}

[[Category:Science tip]]
[[Category:Comics featuring real people]]
[[Category:Science]]
[[Category:Physics]]
[[Category:Programming]]

Talk:1688: Map Age Guide

2024-01-22T20:36:28Z

162.158.91.13:

After the fall of Constaninople it was also known as Ḳosṭanṭīnīye for a while in the Islamic World which you could argue is Constantinople?

I think we should make the second-right and far-right column wider. [[User:Blacksilver|Blacksilver]] ([[User talk:Blacksilver|talk]]) 16:12, 14 November 2017 (UTC)

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Well, I have no clue how to upload the image, it just displays the title text.[[Special:Contributions/108.162.216.91|108.162.216.91]] 12:47, 1 June 2016 (UTC)
:Done. Guess the bot failed because there is a larger one when you click the image on xkcd? --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 13:08, 1 June 2016 (UTC)
::The BOT didn't fail. The was an 404 error, the picture wasn't available at the first time. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 14:03, 1 June 2016 (UTC)
I feel like the title seriously lacks the word "political", there's all sorts of nice things with dating non-modern world maps. -- [[Special:Contributions/141.101.104.104|141.101.104.104]] 13:34, 1 June 2016 (UTC)

It doesn't just cover political maps -- there is a section on telling when you are with physical maps via the presence or absence of bodies of water. In fact, there are four or five main branches: fictional maps, topographical maps, not a map, and political maps (which have two branches, based on the naming of Istanbul (was Constantinople) [[Special:Contributions/108.162.237.174|108.162.237.174]] 13:42, 1 June 2016 (UTC)

I like how that this flow chart also describes what I've drawn[[Special:Contributions/162.158.26.220|162.158.26.220]] 14:05, 1 June 2016 (UTC)

The 1992-1996 range (top right corner) could be narrowed down further with the independence of Eritrea 1993. Am I getting something wrong or did Randall actually overlook this? :-) [[Special:Contributions/162.158.85.141|162.158.85.141]] 14:49, 1 June 2016 (UTC)
:Or the splitting of Czechoslovakia, also in 1993... There are probably others for different time ranges, too. [[Special:Contributions/141.101.95.25|141.101.95.25]] 16:28, 1 June 2016 (UTC)

----
Noone else has started work on this and I'm bored so... (feel free to reorder and/or add more detail where appropriate)
Relevant Events

'''Is there a big lake in Southern California? (Created by Mistake)'''
[https://en.wikipedia.org/wiki/Salton_Sea Salton Sea] A previously dry lakebed accidentally flooded in 1905 while attempting to increase irrigation to the area from the Colorado River

Vietnam unification: the two Vietnams were not united in 1975. Although the communist victory took place with the capture of Saigon in April of that year, the state of South Vietnam continued to exist, under the rule of the Provisional Revolutionary Government, until 1976. The two nations were formally united as the Socialist Republic of Vietnam on July 2, 1976. Ref: https://en.wikipedia.org/wiki/Provisional_Revolutionary_Government_of_the_Republic_of_South_Vietnam [[Special:Contributions/162.158.75.100|162.158.75.100]] 14:28, 7 November 2016 (UTC)
'''How far East do the American Prairies reach?'''
The Northwest Territory was incorporated in pieces ~1820s, there may be something more relavent to draw the line at Indiana though.

'''Is there a big lake in the middle of Ghana? (Created on Purpose)'''
[https://en.wikipedia.org/wiki/Lake_Volta Lake Volta]

'''The US's southern border looks'''
[https://en.wikipedia.org/wiki/Gadsden_Purchase Gadsden Purchase]

'''"Buda" and "Pest" or "Budapest"''' [https://en.wikipedia.org/wiki/Budapest#Etymology Buda and Pest] were originally two different cities

'''Does Russia Border the Sea of Japan?''' Russia currently borders the sea of Japan so the 1867 upper limit is because of Tokyo not existing higher in the chain. The 1858 limit is to do with the [https://en.wikipedia.org/wiki/Treaty_of_Aigun Treaty of Aigun]

'''Rhodesia?''' The dates down the chain suggest this is about [https://en.wikipedia.org/wiki/Rhodesia_(region) Rhodesia the Region] not [https://en.wikipedia.org/wiki/Rhodesia Rhodesia the Unrecognized state] nor [https://en.wikipedia.org/wiki/Southern_Rhodesia Southern Rhodesia] the British Colony {{unsigned ip|162.158.214.218}}

:We are talking about physical/stellite maps at this point of the chart. Incorporation is not relevant. This is about the movement or size change of the American prairies. Climate change, perhaps. Haven't found anything relevant on that, though. Maybe it is about untouched land, as in not having settlements. -- [[Special:Contributions/162.158.85.183|162.158.85.183]] 16:05, 1 June 2016 (UTC)

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Should the relevant links above be added directly to the transcript, or to a separate section? --[[Special:Contributions/172.68.29.127|172.68.29.127]] 14:29, 1 June 2016 (UTC)

:The transcript is only for faithful transcription of the comic. It exists for users who would otherwise be unable to view the regular comic, and should contain nothing but the contents of the comic. Links go in the explanation, if relevant. '''[[User:Davidy22|{{Color|#707|David}}y²²]]'''[[User talk:Davidy22|<tt>[talk]</tt>]] 18:56, 1 June 2016 (UTC)

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Istanbul is not the capital of Turkey! (It's Ankara) [[Special:Contributions/162.158.86.131|162.158.86.131]] 14:41, 1 June 2016 (UTC)
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Maybe a better way of organizing this is chronologically, i.e., show the state of the world each year.

That being said, is every year accounted for? For example, 1857 appears to be missing. {{unsigned ip|162.158.60.41}}

----
From the left and roughly in chronological order (only partial, might add more later):

'The Holy Roman Empire?'
1806 - Dissolution of the [https://en.wikipedia.org/wiki/Holy_Roman_Empire Holy Roman Empire] by Emperor Francis II

'Do Any of These Exist?'

1867 - British North America act passed, marking Canadian independence

- Alaskan Purchase by US from Russian Empire

- Meiji Restoration (in 1869, Emperor Meiji moves to Edo, which is renamed Tokyo)

'Texas is...'

independent - 1836? 35? 34? Texas Revolution

'Florida is part of...'

The US: 1818 - US basically controls East Florida after [https://en.wikipedia.org/wiki/Seminole_Wars#Jackson_invades_Florida First Seminole War] (Spain officially cedes the territory in the [https://en.wikipedia.org/wiki/Adams%E2%80%93On%C3%ADs_Treaty Adams–Onís Treaty of 1819].

'Venezuela and or Ecuador?'

1830 - Both Venezuela and Ecuador become independent as the [https://en.wikipedia.org/wiki/Gran_Colombia Republic of Gran Colombia] dissolves in late 1830, early 1831.

'Does Russia border the Sea of Japan?'
1858 - China cedes territory to Russia under the [https://en.wikipedia.org/wiki/Treaty_of_Aigun Treaty of Aigun], bordering the Sea of Japan (sort of? There's also the Treaty of Beijing)

'South Africa?'
1910 - the Union of South Africa created, thanks to the South Africa Act 1909 enacted by British parliament

'Is Bolivia landlocked?'
1884 - [https://en.wikipedia.org/wiki/Treaty_of_Valparaiso Treaty of Valparaiso] signed ceding Bolivian territory to to Chile, leaving Bolivia landlocked (see also [https://en.wikipedia.org/wiki/War_of_the_Pacific War of the Pacific]

'Buda and Pest or Budapest?'
1873 - Buda and [https://en.wikipedia.org/wiki/Pest,_Hungary Pest] merge to become Budapest

'Is Norway part of Sweden?'
1905 - [https://en.wikipedia.org/wiki/Dissolution_of_the_union_between_Norway_and_Sweden Sweden-Norway dissolved], Norway becomes an independent monarchy

'Rhodesia?'
Rhodesia was named [https://en.wikipedia.org/wiki/Company_rule_in_Rhodesia under the British South Africa Company in 1895]

'Austria-Hungary?'
1918 - Austria-Hungary officially separates into Austria and Hungary

'Albania?'
1912 - [https://en.wikipedia.org/wiki/Albanian_Declaration_of_Independence Albania declares independence] from the Ottoman Empire

'Leningrad?'
1924 - Petrograd ([https://en.wikipedia.org/wiki/Saint_Petersburg Saint Petersburg]) changes its name to Leningrad

[[Special:Contributions/108.162.250.156|108.162.250.156]]

You know there are times where I suspect he's just making some of his comics intentionally hard to explain or very ambiguous just to watch us do somersaults trying to describe them and make it clear, not necessarily for this comic but definitely with some of them it just seems that way. I don't know if he does or not, or how much he even pays attention to this wiki, just a thought. Of course maybe he does just because we're prime nerd sniping material. [[User:Lackadaisical|Lackadaisical]] ([[User talk:Lackadaisical|talk]]) 16:00, 1 June 2016 (UTC)

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I'm pretty sure 'is it larger than a breadbox' is a reference to 20 questions. [[Special:Contributions/108.162.216.77|108.162.216.77]] 16:11, 1 June 2016 (UTC)

:From the Wikipedia page for [https://en.wikipedia.org/wiki/Breadbox 'Breadbox']: "The most common reference to breadboxes is the phrase "Is it bigger than a breadbox?" when trying to guess what some surprise object may be. This question was popularized by Steve Allen on the American game show What's My Line? where he initially asked the question on 18 January 1953. It remains a popular question in the parlor game 20 Questions." [[Special:Contributions/141.101.98.16|141.101.98.16]] 17:48, 1 June 2016 (UTC)

Note that it is very hard to even ''find'' Jan Mayen on an actual world map (even a political one), never mind figure out which country it belongs to. So anyone actually following these questions might (in some cases) get derailed fairly easily. [[Special:Contributions/141.101.81.77|141.101.81.77]] 18:20, 1 June 2016 (UTC)

::You will only get there if you can't find Istanbul/Constantinople, you can't find the Ottoman Empire, you can't find North Korea, and Soviet Russia can't find you. Note that the "no" box actually says "not yet". If you can find any of those four, you will never reach the Jan Mayen box. You will also never answer "yes" to the Jan Mayen box, as that would contradict the Soviet Union and North Korea not existing. [[Special:Contributions/108.162.219.9|108.162.219.9]] 20:34, 1 June 2016 (UTC)

::I tried to explain that a response of "What?" is interpreted to be unable to find Norway, not Jan Mayen, for this reason and that the name didn't exist until 1620, but then I couldn't eliminate that the map is from 1299 or earlier, because the kingdom of Norway is not that old. As for the "Yes" response, for a short period between November 1 and December 28, 1922, neither the Soviet Union nor the Ottoman Empire existed, and Norway had already received jurisdiction over Jan Mayen then.--[[User:Troy0|Troy0]] ([[User talk:Troy0|talk]]) 07:16, 2 June 2016 (UTC)

::I stumbled on this when trying to apply the test to the Yakko's World map (which is normally mid-1990 - total of Yemens and Germanys is 3; of course, that's because there's 2 Yemens and 1 Germany, and the intended date was probably in 1991). As it happens, the Soviet Union is labelled "Russia", Korea is shown as unified, and Istanbul is not labelled at all but the country is Turkey, so we get to the Jan Mayen question. (I hadn't looked at thar map precisely enough to figure out if Jan Mayen is there at all, but it must be Norwegian if it does appear. However, even if we answer "yes", it would not be possible to reach the 1990 option anyway [we get 1954-57, in fact]. OTOH, if we accept that the Soviet Union is there, we correctly reach the Micronesia question, and the mid-1990 option is close enough to that to be able to guess correctly.) [[Special:Contributions/141.101.80.30|141.101.80.30]] 13:56, 3 June 2016 (UTC)

----

Update picture, please: The "giant French blob" "yes" option points to the correct box (Pakistan) on xkcd.com but not on this page (Bangladesh), and the incorrect version leaves out approximately 1930-1960. [[Special:Contributions/108.162.219.9|108.162.219.9]] 20:34, 1 June 2016 (UTC)

I fleshed out the Narnian section with links to the original illustrated maps from several books (but this gets weird in a hurry because there is no consistency of illustrations across the various editions of the books). I think it deserves to be mentioned in the article (although I did not try) that Randall is being slightly disingenuous with the history of maps of Narnia. For instance, there is no published map with sufficient detail to determine if Beruna has a ford or a bridge, neither can I find a map that includes Aslan's Country. On the other hand, it is also not an accurate history of the geopolitics of Narnia; for instance, Calormen existed during the time of the first three books even if it wasn't listed on any of the authorized maps. Also, it is the first time I have helped to edit an article, so I apologize for the quirkiness (especially the reliance on non-wikipedia links). [[User:Mwdaly|Mwdaly]] ([[User talk:Mwdaly|talk]]) 02:55, 2 June 2016 (UTC)

The introduction to the Narnia section reminds me of Douglas Adams' discussion of the difficulties of tense formation in time travel [http://hitchhikers.wikia.com/wiki/Time_Traveler's_Handbook_of_1001_Tense_Formations], differences between writing/publication order and reading order are very like time travel. [[Special:Contributions/141.101.70.217|141.101.70.217]] 16:24, 4 June 2016 (UTC)
----
Any particular reason the Crimea description was edited to be so much more condemning of Russia? I could understand if it was originally written that way, but it was changed essentially to put Russia's actions in a negative light. Is that something that needs to be done? {{unsigned ip|108.162.237.174}}

;My map doesn't fit the chart... I think?

I've got a Stanford's General Map of the World (On Mercator's Projection) from 1968. My answers:

Istanbul '''->''' The Soviet Union exists '''->''' West Africa is ''not'' a giant French blob '''->''' Only one Vietnam '''->''' Jimmy Carter is fine... I think? The only animals on my map are Poseidon and a seahorse '''->''' Sinai is mostly Egyptian...

Bangladesh exists, and below Victoria is Tanzania; so where's the second Vietnam I've failed to locate on my map? [[User:Mr FJ|Mr FJ]] ([[User talk:Mr FJ|talk]]) 20:44, 1 June 2016 (UTC)

:Your map is optimistic in suggesting there is only one Vietnam, as 1968 was in the heart of the Vietnam War. [[Special:Contributions/141.101.98.123|141.101.98.123]] 22:42, 1 June 2016 (UTC)

;Saint Trimble's Island

I think the real question is: how long until there actually is one on this planet, even though Randal claims to have made it up.
--[[User:Divad27182|Divad27182]] ([[User talk:Divad27182|talk]]) 03:30, 2 June 2016 (UTC)

Perhaps this should refer to Sandy Island. [http://www.theguardian.com/world/2012/nov/22/sandy-island-missing-google-earth] [[Special:Contributions/141.101.70.217|141.101.70.217]] 16:18, 4 June 2016 (UTC)

There was a Trimble Island https://en.wikipedia.org/wiki/Blake_Island [[Special:Contributions/162.158.159.136|162.158.159.136]] 11:51, 30 June 2020 (UTC)
----

Appearantly the year of an event is included in intervals after the event, but not in those prior. How do we handle it? [[User:Troy0|Troy0]] ([[User talk:Troy0|talk]]) 03:46, 2 June 2016 (UTC)

;Flaws

Going on the path '''neither''' - '''no ottoman empire''' - '''no soviet union''' - '''no north korea''' - '''jan mayen is norwegian''' I will get results that all belong to a time were the soviet union existed. Am I doing it wrong?--[[Special:Contributions/162.158.92.175|162.158.92.175]] 08:01, 2 June 2016 (UTC)
:This path implies a time interval between November 1 and December 28, 1922, so it is unclear why it is linked to the Istanbul Division, which is 1928 or later.--[[User:Troy0|Troy0]] ([[User talk:Troy0|talk]]) 08:28, 2 June 2016 (UTC)

;Did it work on your map?
;Worked:
I just tried this out on an old Danish world atlas (''Lademann Verdensatlas'' with most English names also included). And although I could not determine the capital of Micronesia, I found out that it was still called Upper Volta not Burkino faso and thus the map should be from 1982-1984. First then did I check the release date for this map and true enough it was from 1982! Cool. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:41, 2 June 2016 (UTc)

it can guess modern maps
;Didn't work:
A map [http://digitalcollections.nypl.org/items/510d47db-b011-a3d9-e040-e00a18064a99#/] in the New York Public library, dated 1840, is given a date of 1818-1830. Notably this map has Texas as part of Mexico (though mentioned as in captials indicating a district within Mexico. It is also missing independent Paraguay, Ecuador and Venezuela. [[User:Zeimusu|Zeimusu]] ([[User talk:Zeimusu|talk]]) 10:04, 3 June 2016 (UTC)

Apparently most Mars maps were made in 1922-1932. No Istanbul/Constantinople, no Ottoman Empire, Soviet Union exists (e.g. Mars 3 and Mars 6), no Saudi Arabia... --[[Special:Contributions/173.245.52.62|173.245.52.62]] 11:18, 2 June 2016 (UTC)

I have been evaluating world globes (subset of maps of course) for several years, and find this quite amusing. A note of interest: Apparently Randall knows that maps often do include copyright or other dates, while globes with very few exceptions do not include a date. There are other guides to finding the date of presentation of a globe of course, which may or may not pin the date down more precisely. [[User:Pault151|Pault151]] ([[User talk:Pault151|talk]]) 05:38, 3 June 2016 (UTC)

Hugo Giraudel made a command line version of this: https://github.com/HugoGiraudel/map-dater (full disclosure: I helped) [[User:Haroenv|Haroenv]] ([[User talk:Haroenv|talk]]) 16:24, 13 June 2016 (UTC)

Starting at the Istanbul Division, the Question Date Range no longer fits the definition at the top of the table, and now includes the effects of the Prior Date Range. [[Special:Contributions/172.68.46.5|172.68.46.5]] 07:03, 20 March 2017 (UTC)

I tried to apply this to a map of Pangaea and ended up being taken to the "you made this yourself" part... [[Special:Contributions/162.158.78.106|162.158.78.106]] 09:49, 27 August 2017 (UTC)
:It's very nice.[[Special:Contributions/162.158.58.249|162.158.58.249]] 12:22, 25 October 2017 (UTC)

How come Istanbul can both exist and not exist on a map of the same date. They can both lead to Zare/Zaire. [[User:Netherin5|Netherin5]] ([[User talk:Netherin5|talk]]) 18:04, 12 February 2019 (UTC)

Munroe writes: "(Assuming it's complete, labeled in English, and detailed enough)" which is unfortunately not enough of an assumption. Some publishers are notorious for updating slowly. Like looking at the light that left a galaxy several years ago, you may be looking at a map that reflects reality the last time the publisher really updated it (and did not just slap a new date on it). Also, there's Constantinople. Which still shows up on maps of Greece, published in English, in Greek. In fact, the list of facts that map-makers deny or have denied for political reasons is huge. It's why this game (which I used to play when I was a kid - 2 Pakistans and the name of the Congo were major indicators) can be frustrating. And no, we did not use UAR, since different mapmakers handled it differently.
Hey, I found this one with Smyrna: https://www.greektravel.com/maps/greece.html Can someone find one with Constantinople?
Oh, oh, and I used to be a cartographer. It doesn't make me right, but I like saying it. [[User:Jd2718|Jd2718]] ([[User talk:Jd2718|talk]]) 23:41, 21 December 2020 (UTC)

The alert box at the top of every page needs to be changed, as this explanation is no longer incomplete.
: Agreed. maybe change it to 1975: Right Click? [[Special:Contributions/172.69.62.62|172.69.62.62]] 17:21, 7 August 2021 (UTC)Bumpf

Um... o-oh dear. We should probably start keeping an eye out for those spiders... [[User:LendriMujina|LendriMujina]] ([[User talk:LendriMujina|talk]]) 19:53, 28 January 2022 (UTC)

Can Colorado hurry up and have a nuclear meltdown? It's 2022. [[User:Beanie|Beanie]] [[User talk:Beanie|talk]] 23:16, 24 February 2022 (UTC)

Regarding "A map that does not include either the HRE or the USA must be older than the HRE, which would put the map sometime prior to 1000 AD, when there really were no countries, and English wasn't used yet, hence Randall's comment". " I could be wrong, but my interperation of this was that a map that isn't in English wouldn't list the HRE or USA ''under those names'', regardless of when it was made. Like, I'm imagining someone going through the flowchart thinking "Nope, I'm seeing something called the Sacrum Imperium Romanum, but no Holy Roman Empire." [[Special:Contributions/162.158.74.3|162.158.74.3]] 13:00, 27 January 2023 (UTC)

Hey guys the spiders never showed up :( [[Special:Contributions/162.158.91.13|162.158.91.13]] 20:36, 22 January 2024 (UTC)

2882: Net Rotations

2024-01-18T01:12:00Z

162.158.91.13: /* Transcript */ more physics related

{{comic
| number = 2882
| date = January 17, 2024
| title = Net Rotations
| image = net_rotations_2x.png
| imagesize = 318x477px
| noexpand = true
| titletext = For decades I've been working off the accumulated rotation from one long afternoon on a merry-go-round when I was eight.
}}

==Explanation==
{{incomplete|Created by a DIZZY ROBOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[Cueball is standing on one leg in front of a whiteboard with his arms crossed, thinking to himself. There are circular curves around Cueball indicating rotary motion. The whiteboard contains two vertical helix-like curves crossing over each other at multiple points and other notes shown as rows of illegible scribbles, the bottom one of which is circled. There is a thought bubble over Cueball.]
:Cueball (thinking): ...and three lefts for going down the stairwell at work, two rights from cloverleaf interchanges, minus one for the Earth's rotation...
:Cueball (thinking): Okay, that's a net of 17 right.

:[Caption below the comic:]
:Spacetime health tip: Remember to cancel out your accumulated turns at the end of each day to avoid worldline torsion.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Astronomy]]
[[Category:Physics]]
[[Category:Tips]]