explain xkcd - User contributions [en]

3032: Skew-T Log-P

2025-01-03T02:03:13Z

172.69.134.230: /* Explanation */ The two lines have similar features to the dewpoint and temperature in the real example graph.

{{comic
| number = 3032
| date = January 1, 2025
| title = Skew-T Log-P
| image = skew_t_log_p_2x.png
| imagesize = 569x626px
| noexpand = true
| titletext = The most important quantity for meteorologists is of course the product of latent pressure and temperostrophic enthalpy, though 'how nice the weather is' is a close second.
}}

==Explanation==
{{incomplete|Created by a BOT CLEANING UP AFTER DAVE - This needs an explanation. Table not filled out. Also the title text was not mentioned at all. I added a very simple start to this, but nothing about what the product actually means, please expand... Do NOT delete this tag too soon.}}

{{w|skew-T log-P diagram|Skew-T log-P diagrams}} are commonly used to plot {{w|atmospheric sounding|atmospheric soundings}} collected by {{w|weather balloon|weather balloons}}. The name comes from the temperature (T) lines being skewed at a 45-degree angle, and the pressure (P) lines being logarithmic in scale.

Because the diagrams have a lot of lines on them (isobars, isotherms, adiabats, and mixing ratios, and that's before plotting the actual measurements of temperature and dew point temperature), they can be hard to understand. The comic pretends to offer an explanation of one such diagram, but most of the explanations are blatantly incorrect or humorous in nature. The diagram appears to have either measurements from two separate weather balloons or the measured temperature and dewpoint from a single balloon, with solid lines for rising balloon(s) and dashed ones for popped balloon(s) falling back down. Two lines and various styles of lines in real diagrams generally mean different measurements from the same balloon (or other sensor platform) track. See details in the [[#Table with terms|table]] below. Many weather balloons are designed to rupture after reaching a certain height high in the atmosphere.

In the title text it is stated that "The most important quantity for meteorologists is of course the product of latent pressure and temperostrophic enthalpy, though 'how nice the weather is' is a close second". So it jokes by comparing a non-existent, complicated-sounding product (temperostrophic enthalpy is not actually a thing) with a simple sentence about how nice the weather is.

[[File:Annotated_Skew_T_diagram.png|thumb|An actual Skew-T Log-P diagram, with several real annotations. The X-axis has temperature (blue diagonal lines in diagram) and the Y-axis has pressure in millibars.]]The true design of a Skew-T Log-P diagram is intended to best represent the nature of the weather in any given column of atmosphere. The pressure (vertical axis, with pressure being closely but not exactly inversely related to altitude) is shown as a logarithmic scale (i.e., Log-P) because it makes altitudes nearly evenly spaced. Plotting pressure proportionately (which must also be from top to bottom, to match its general relationship with altitude) would space features out in ways that would be hard to use and interpret, whereas the logarithmic scale is far more pragmatic. The temperature scale is deliberately tilted, rather than orthogonal, which (together with the logarithmic nature of the inverted pressure scale) allows the typical way that temperatures fall with altitude(≈as pressure falls) to trend roughly vertically, give or take the notable changes that are key to understanding the forecast. Other measurement lines, differently skewed and often also curving across the temperature/pressure skewed-log 'grid', represent various other idealistic relationships (where both T and P vary, keeping another measure constant) that are useful references to meteorologists.

Upon this style of graph are plotted the ''actual'' measurements obtained by releasing a weather balloon or other sensor. As well as the variation of actual temperatures and pressures, other retrieved and calculated data is plotted, such as the {{w|dew point}}. The dew point, a function of the air's {{w|absolute humidity|water content}}, temperature, and pressure, is where condensation begins. By observing how the actual measurements and dew point line converge and cross, the development and nature of clouds can be tracked and pinned to specific cloud layers. Further details may also be included, such as wind-direction and wind-speed indications (often to the side of the plot) to give a visual cue about possible {{w|wind shear}} and/or to suggest which direction of adjacent weather-station readings may hold clues as to what changes may later blow in above the current site.

==Table with terms==
{| class="wikitable"
!Item in comic
!Correct?
!Explanation
|-
| Pressure latitude || No || {{w|Pressure altitude|Pressure ''altitude''}} is the height above a standard datum plane, a theoretical level where the pressure of the atmosphere is 1013.24 millibars (29.921 inHg). It's essentially an estimate of altitude calculated from atmospheric pressure.
|-
| Enthalpic pressure || ||
|-
| Entropic density || ||
|-
| Latent heat of cooling || ||
|-
| Isobars || Yes || Lines denoting equal ("{{wiktionary|iso-}}") air pressure ("{{wiktionary|bar-|-bar}}"), probably most often recognized as the indicators of how ground-level pressures change (or not) across the horizontal area depicted on a weather ''map''. In this type of chart, which depicts data obtained from above a single point, it has the same meaning but is instead a pre-existing reference line across which the actual data is plotted, and does not itself indicate the nature of any wind.
|-
| Omnitrophic wind || No || Something "omnitrophic" would apparently be "all-eating", in some scientific sense. An omnitrophic wind would probably be a concerning phenomenon.
Probably a play on something like {{w|geostrophic wind}} ("geo"+"strophic" being from "Earth curving"), a theoretical state of wind that results from an exact balance between the {{w|Coriolis force}} and the {{w|pressure gradient}} force.
|-
| Isomers || No || Different forms of molecules with the same formula, with the atoms or functional groups arranged differently. An example would be propanol, which has three isomers. One of the most common isomers of propanol has its OH functional group in the middle, so is called isopropyl alcohol or isopropanol.
However, these are actually iso'''therm''' lines, representing equal temperature.
|-
| These lines are slightly different because Dave messed them up || No || Indicating isotherms (or, according to the comic, "isomers"), the suggestion is that slightly wrong lines were drawn by Dave and had to be corrected.
The real reason for the not quite identical lines is that the measured temperature at a given pressure can be converted to or from the ''potential'' temperature that the same air would have if at a standard pressure (holding the same amount of heat energy). For practical reasons, both for composing and interpreting the eventual plot, each of the slightly differently skewed isotherms are given, usually in clearly differentiable styles of line.

The "Dave" of the description may be David Bolton, whose 1980 paper introduced a means of calculating the atmosphere's potential temperature<ref>https://journals.ametsoc.org/view/journals/mwre/108/7/1520-0493_1980_108_1046_tcoept_2_0_co_2.xml</ref>.
|-
| Line of constant thermodynamics || No ||
|-
| Uncomfortably moist adiabat || Wrongly placed, unusually qualified|| This labels a segment of isotherm, which is the exact 'opposite' of an adiabat.
An adiabat is a line along which temperature can change for a given mass, without changing the amount of energy. This is primarily made possible by changing the density (by a change in pressure) of the gas. There are typically two types of adiabat, marked for reference on the plot, "dry adiabat" (curves across the isotherms perpendicularly, to create a largely square but slightly curved grid with them), and "moist/saturated adiabat" (the latter's heat-maintaining profile is influenced greatly by the humidity content, and produces graphing lines vastly different from the equivalent "dry" versions). Randall has declared this (erroneous) type of adiabat to be "uncomfortably" moist, so presumably not totally saturated but also not subjectively 'pleasant'.
|-
| Oops, the balloon flew through a ghost || No || Ghosts do not exist.{{cn}} However, one of the purported effects of ghosts (such as in the film *The Sixth Sense*) is a transient/local lowering of temperature around and/or inside them. The line is interpreted as showing a local low temperature encountered at this pressure(/altitude).
This line, however, is probably the dew point line, indicating that in passing through this layer of the atmosphere, a drier band of air was encountered which would theoretically be cooled a lot more before the water-vapor oversaturates it and liquid water droplets form.
|-
| No birds up here :( || Yes* || This point is near the top of the diagram, with an air pressure of about 110 millibar - about 15 kilometers (50,000 feet) above sea level. This is well above the highest [https://peregrinefund.org/explore-raptors-species/vultures/ruppells-vulture flight height of any known bird species]. However, this information is irrelevant to the purpose of a skew-T log-P diagram.
|-
| Track of rising weather balloon || Yes, partially || Although there are other ways of recording these details, this is typically the record of a rising balloon.
However, it would be a track of the balloon through the varying pressures and temperatures that it records (as the second line of this type records the measurements of dew point at each pressure value). Moreover, circumstances that would make the recorded data plot out a neat {{w|figure-eight knot}} (see "Seems bad", below) are very unlikely.
|-
| Track of popped balloon falling back down || Possible, partially || A standard plot track will include two strong lines, as this has, representing not ''two'' balloons but the recorded temperature track ''and'' the dew point track, both against the (altitude surrogate) progressive pressure changes at each pressure-point.
A further pair of tracks as dotted lines could possibly be from a different launch (earlier, later or simultaneous from an adjacent location) as an analytical reference, but ''may'' indeed be the additional results obtained as the scientific package rapidly descends once the balloon pops.
|-
| Meteogenesis || No || The chart purports to show the path of two weather balloons crossing and labels the space between them with a new word. The root "meteo" means something high up (in this case, balloons) and "genesis" means creation. The implication is that a new balloon was created, though no third flight path is shown so it presumably did not fly separately or was not tracked.
In reality, one of the tracks (almost certainly the left one) is the track of the measured dew point. Where the line of the existing conditions cross this line is where the moisture will precipitate out and form clouds, a process that might well be called "{{wiktionary|meteor#English|meteo}}+{{wiktionary|genesis#English|genesis}}", but {{w|Cloud physics|isn't}}.
|-
| Seems bad || Not a common feature || The path of the balloon loops around in the shape of a {{w|figure-eight knot}}, which would indicate very chaotic conditions at that point, if taken as positional informtion
As the actual Skew-T Log-P graph does not record positional information, this is best interpreted as having encountered a fluctuating temperature as the pressure decreases, continuing as something (possibly {{w|Wind shear#Vertical component|vertical wind shear}}, or some form of compression waves, encounter the instruments) creates a temporary increased in external pressure and then circumstances return it to its more typical altitude-induced pressure-drop. Though this is not ''impossible'' to naturally happen, it might even be best interpreted as the instruments being deliberately 'buzzed' by a passing aircraft or rocket, including some intermittent form of thermal backwash as the interfering craft criss-crosses the balloon's physical track in a briefly complex encounter.
 Whatever happened to the temperature/pressure track, it apparently did not significantly change the associated dew-point/pressure track (if the pressure did indeed temporarily rise, the related dew points repeated themselves each time the pressure values were re-encountered).
|-
| Dew point || Wrongly represented || The temperature at which water condenses out of the air, and therefore dew starts to form, given the amount of water vapor in the air. It is shown here as an ''actual'' single point, when it should be a line (typically the leftmost solid plotted line) representing the temperature at which dew should form at any given pressure.
|-
| Humidor || No || In reality, is a {{w|Humidor|container}} that is used maintain a more controllable humidity within which to store smoking products. In the graph, points at the line that is probably representing the dew point, which is represents the ''actual'' humidity encountered.
|-
| Heavyside layer || No || Probably a misspelling of the {{w|Kennelly-Heaviside layer|(Kennelly-)Heaviside layer}}, also called the E region of the {{w|ionosphere}} that was co-discovered by {{w|Arthur E. Kennelly}} and {{w|Oliver Heaviside}}. In this diagram it is apparently labeling a heavily marked isotherm, or line of constant temperature - most likely the 0°C line, the freezing point of water that is of great importance to meteorologists, pilots, etc.
|-
| These lines are tilted because the wind is blowing them || No || The wind is not actually a derivable featured of this diagram, which does not have data of either direction or strength of air movement.
These lines are actually dry adiabats (see above), possibly two sets due to a similar renormalized interpretation, as with the isotherms, at a given reference pressure.
|-
| Don't stand here or you might get hit by a balloon || No || This is a diagram of some measurements, not a place you could stand.
|}

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

:How to interpret a skew-T log-P diagram
:[The comic shows a skew-T log-P diagram. On it are various labels, including isobars, comments, and other interpretations of the diagram.]
:[Left to the diagram is an upwards-pointing arrow with the label "Pressure Latitude". Right to the diagram is a downwards-pointing arrow with the label "Entropic Density". Below the diagram is a right-pointing arrow with the label "Enthalpic Pressure".]
:[The remaining various labels are inside the diagram.]

==Trivia==
*Even though this comic was released on New Year's Day 2025, it was not a [[:Category:New Year|New Year comic]].
**Only second time this has happened since New Year comics became a regular thing from 2011.

{{comic discussion}}

[[Category:Charts]]
[[Category:Weather]]

Talk:3011: Europa Clipper

2024-11-14T11:04:57Z

172.69.134.230:

I'm not brave enough to actually add an explanation myself, quite yet, but ... I guess this is a reference to the fact(?) that Europa looks a bit like a creme brulee', when viewed from space? https://science.nasa.gov/jupiter/moons/europa/ It does look tasty ... :) [[User:ModelD|ModelD]] ([[User talk:ModelD|talk]]) 12:53, 13 November 2024 (UTC)
:I suspect it's more due to the need to drill through a couple miles of ice to get to the ocean; much like breaking through the sugar crust on a creme broule! [[User:Seebert|Seebert]] ([[User talk:Seebert|talk]]) 13:16, 13 November 2024 (UTC)

Thank you to the people at 9AM Post things on another website to try and explain XKCD Comics. -Forgotten_Mail {{unsigned ip|172.69.33.177|13:30, 13 November 2024}}

The comically large spoon!!!!!!!!!! I love those. -[[User:Psychoticpotato|P?sych??otic?pot??at???o ]] ([[User talk:Psychoticpotato|talk]]) 16:38, 13 November 2024 (UTC)
: Don't be sucked in! Protect yourself! https://rathergood.com/2017/02/10/spoonguard/ [[Special:Contributions/141.101.99.105|141.101.99.105]] 10:57, 14 November 2024 (UTC)

I think the "Crème brûlée is from France, France is in Europe, the moon is called Europa" connection is a bit of a stretch...? [[User:Yorkshire Pudding|Yorkshire Pudding]] ([[User talk:Yorkshire Pudding|talk]]) 18:36, 13 November 2024 (UTC)
: Eh, it's the same etymology. --[[Special:Contributions/172.69.134.230|172.69.134.230]] 11:04, 14 November 2024 (UTC)

"only a spoonful" moment 💔 [[User:CalibansCreations|'''Caliban''']] ([[User talk:CalibansCreations|talk]]) 19:20, 13 November 2024 (UTC)

Someone should add a reference to XKCD's previous mention of a Planetary Protection Officer: https://what-if.xkcd.com/117/ [[Special:Contributions/162.158.42.221|162.158.42.221]] 00:09, 14 November 2024 (UTC)

JUICE mentioned!!! cracker ham cheese cracker ham cheese cracker [[User:N-eh|N-eh]] ([[User talk:N-eh|talk]]) 07:31, 14 November 2024 (UTC)

3010: Geometriphylogenetics

2024-11-14T09:54:10Z

172.69.134.230: /* Explanation */

{{comic
| number = 3010
| date = November 11, 2024
| title = Geometriphylogenetics
| image = geometriphylogenetics_2x.png
| imagesize = 316x391px
| noexpand = true
| titletext = There's a maximum likelihood that I'm doing phylogenetics wrong.
}}

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

{{w|Phylogenetics}} refers to the practice of examining relationships among things that follow the principle of "descent with modification of progeny". In the course of descent with modification, one thing may give rise to two (the progeny), different modifications happen to each, and those modifications become established. Iterated "splits" over time yield a tree of objects; it is the purpose of phylogenetics to recover ("reconstruct") these trees, and use the information gained to inform study of the things contained. Phylogenetics has been most commonly applied to the classification/taxonomy of biological species and investigations of their evolutionary history, but it has also been used to examine the evolution of genes and biosynthetic pathways. Similar conceptual approaches have been used in the study of human languages and their evolution.

Data for phylogenetic analyses may come from any attributes ("characters") of the things being examined. {{w|Computational_phylogenetics|Rigorous techniques}} for these analyses became available starting in the {{w|Willi_Hennig|1950s}}, and these replaced earlier methods based largely on the individual judgement of experts. In phylogenetic studies of organisms, their DNA is far and away the most data-dense source of information, and consequently, most present-day investigations are based on analyses of selected genes and, increasingly, whole genomes. Thanks to the advent of more robust datasets, and more robust methods of data analysis, it is now commonplace for studies, especially on relatively understudied creatures, to reconstruct an evolutionary history (a phylogeny) that is radically different from what had previously been assumed. This is the "phylogenetic revolution" referred to in the caption. One example is the genus {{w|Hippopotamus|Hippopotamus}}, which had been considered a relative of pigs, which the animals somewhat resemble, until modern data and methods revealed it to be more closely related to whales, despite the animals being very different physically (hippos spend time in water, but [https://www.youtube.com/watch?v=X-YRJCSZRJU can't swim]).

This comic presents a tree, which resembles and purports to be a phylogenetic tree, in which the endpoints ("terminal taxa") are geometric shapes. This has been given the name "geometriphylogenetics" — a portmanteau of "{{w|geometry}}" and "phylogenetics". The claim is that triangles have been moved from the lower part of the tree (where they would be closely related to squares, rectangles, pentangles, and the like) to the upper part (placing them closer to circles and ellipses). This is a riff on the findings, and even the wording, of authentic phylogenetic research papers that report "revolutionary" results. The absurdity, and the joke, is that geometries do not change over time. Human understanding might change, but triangles and circles and rectangles themselves did not evolve or descend from ancestors, they are not progeny of some other geometries of ages past, and therefore phylogenetic principles and techniques don't apply to their study. Moreover, geometries do not contain DNA,{{cn}} so genetic analysis, even if it was ever relevant, is impossible.

The title text alludes to {{w|Computational_phylogenetics#Maximum_likelihood|maximum likelihood}}, one of the most robust, and most frequently used, methodologies for phylogenetic analysis. The method builds a number of trees from the data, assigns to each a probability that it conforms to a pre-selected model of evolution, and then selects the tree that has the highest (maximum) likelihood of conformity to the model. In this case, though, the statement "There's a [high probability] that I'm doing phylogenetics wrong" doesn't just have the maximum probability of the available options; it has the maximum ''possible'' probability of 1, because it is definitely the case.

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

:[A tree diagram, or a dendrogram is shown, consisting of lines that branch off from left to right, starting with one horizontal line on the left. Eight results are shown on the right: ellipse on Path 1, circle on Path 2, triangle on Path 3, parallelogram on Path 4, trapezoid on Path 5, square on Path 6, rectangle on Path 7, and a pentagon on Path 8. The paths are listed in order top to bottom.]
:[Path 3 and the triangle are bold black, while the other branches are dimmer. The paths are connected as follows: Path 2 and 3 are connected, then both connect together to Path 1; Path 4 and 5 are connected, as are Path 6 and 7, and these two paths are connected altogether; Path 8 is then connected to the branch containing Paths 4 to 7. All of Paths 1 to 3 are then connected to Paths 4 to 8, the branches all culminating in a single line on the left.]

:[Caption below the panel:]
:The phylogenetic revolution continues:
:Triangles were long believed to be related to squares, but genetic analysis proves that they are actually very pointy circles.

{{comic discussion}}

[[Category:Geometry]]
[[Category:Biology]]
[[Category:Charts]]
[[Category:Statistics]]

2948: Electric vs Gas

2024-06-26T00:43:52Z

172.69.134.230: Grammar fix

{{comic
| number = 2948
| date = June 19, 2024
| title = Electric vs Gas
| image = electric_vs_gas_2x.png
| imagesize = 284x385px
| noexpand = true
| titletext = An idling gas engine may be annoyingly loud, but that's the price you pay for having WAY less torque available at a standstill.
}}

==Explanation==
{{incomplete|Created by a HYDROGEN INTERNAL COMBUSTION ENGINE RUNNING A GENERATOR. Do NOT delete this tag too soon.}}

{{w|Internal combustion engine|Internal combustion engines}} (ICEs) have long been the most common technology used to propel motor vehicles. In US vernacular, the most common vehicle fuel is known as "{{w|gasoline}}", or "gas" for short, leading to these engines being referred to as "gas engines". Gasoline is a product of petroleum refinement, leading to the name "petrol" being used in other dialects.

{{w|Traction motor|Electric motors}} would seem the more well-suited method for propelling a vehicle, and as early as 1885 were an actual form of motor car engine with which the fledgling internal combustion engine had to compete. Despite this early popularity, over most of the 20th century electric motors were sidelined in everyday car design, as supplying the electricity was considered to be impractical for most forms of transportation. Modern forms are rapidly rising in popularity, and [https://www.iea.org/reports/global-ev-outlook-2024/trends-in-electric-cars now constitute 18% of all global vehicle sales]. [[Randall]] is a strong proponent of {{w|electric vehicle}}s (EVs).

In this strip, [[White Hat]] claims to be comparing the pros and cons of electric motors and gas engines. The joke is that every point he makes goes in favor of electric motors. Despite it being posed as a dilemma, it may be very clear which side of the debate White Hat is promoting. On the other hand, it may indicate that one of the things we might consider a pro in electric motors (the instantaneous power now available, exceeding that of many non-electric engines) he would consider a problem — perhaps more accurately, a problem with the ''drivers'' of such vehicles — recklessly using the enhanced capabilities to accelerate to high speeds at all opportunities, whether safe to do so or not.

The strip offers the following points in favor of electric motors:

* "Cleaner and more efficient". ICEs produce and vent harmful combustion products and toxic chemicals, while electric motors produce no emission byproducts at the point of use. The efficiency of both gas and electric motors vary, but the typical ICE vehicle in the US converts around 25% of available energy into motion, while the typical electric vehicle is in the neighborhood of 80%. Even when considering inefficiencies in the source production and transmission and storage and release of energy, battery-driven electric vehicles are generally more efficient than internal combustion propelled vehicles[https://www.factcheck.org/2024/02/electric-vehicles-contribute-fewer-emissions-than-gasoline-powered-cars-over-their-lifetimes/]. It should be noted that all of this refers to the motors only, and ignores how the fuel and electricity are produced, or the wider environmental impact of the vehicle.

* "More powerful". Electric motors are able to deliver a lot of power from a small motor ''if'' an ample energy supply is available, and can do so 'on demand', often far quicker than a fuel-powered engine that has to put its power through a gearbox in order to service a wide range of road velocities, from standstill to the eventual top speed. Due to battery limitations, short or partial runtime use cases (such as dragsters, hand tools, yard tools, toys and electric scooters) net the most benefit from the small size of a high-powered electric motor.

* "Annoyingly loud". ICEs, by their nature, produce significant noise. Despite noise attenuation measures such as mufflers, they contribute significantly to urban noise. Properly designed electric motors are nearly silent (even if the rest of the vehicle is not). In particular, {{w|blowoff valve|turbocharger blowoff valves}} make particular noises that are completely lacking in an all-electric vehicle being driven at a similar performance level. This might legitimately be considered a problem, though, when everyone is used to a rapidly approaching vehicle providing a very noisy warning of its approach. EV makers have sometimes added [https://www.businessinsider.com/electric-car-ev-fake-engine-sound-hyundai-dodge-toyota-2023-7 fake ICE noises] to appeal to older drivers, and in the U.S. and some other countries, EVs are required to have {{w|Electric vehicle warning sounds|warning sounds}} at low speeds for pedestrian safety. At highway speeds, the noise of tires against the road is much louder than a properly muffled ICE, so the intrinsic quietness of an EV's motor is irrelevant in that context.

* "WAY less {{w|torque}} available at standstill". ICEs need to continually operate within a specific range of rotational speeds, which means that a complex system of {{w|transmission|transmission gearing}} is needed to convert this motion into the specific speeds needed at the wheels. When starting from a standstill, this means that torque must be applied to the wheels relatively gradually to avoid stalling the engine. In addition, when a vehicle is standing still, the motor is typically idling at (very) low speed and must be sped up before it produces significant acceleration. Electric motors, in contrast, generally produce their peak torque when at a standstill. This results in electric vehicles having significantly better acceleration and engine responsiveness. Again, this could cause a legitimate problem with drivers changing from ICE to electric motors, because the new cars accelerate more than the driver is used to and provide different feedback. The audible clues of gear changes, whether from automatic or manual systems, are part and parcel of what many people have grown up with and come to rely on in anticipating what might need paying attention to.

The strip offers no points in favor of internal combustion (gas) motors, even those framed as if they were such.

It should be noted that White Hat is deliberately confining his arguments to electric vs gas ''motors'' rather than electric or gas-powered ''vehicles''. Doing so ignores the basic reason why internal combustion vehicles have long dominated transportation in certain specific countries: hydrocarbon fuels are a very dense and fairly easy to handle form of energy ''storage''. Providing electrical power to a moving vehicle requires either that the vehicle remain in contact with a power line (as with an electric train or a tram) or else to carry a high-capacity battery (and the ability to recharge that battery in a reasonable amount of time, while stationary). More popular in the USA is a hybrid system, where a combustion engine provides at least some of the power to an electric motor, which was impractical until comparatively recently. Other methods, such as hydrogen fuel cells (a form of "combustion" that can be used more directly to form electricity), have been proposed, but remain niche, due to various barriers to adoption, or experimental.

A more comprehensive comparison would include many more factors, both against and in favor of electric cars.

Issues raised with electric vehicles typically include:
* Higher cost of purchase (primarily due to the cost of batteries and, in the USA, now a 100% tariff on Chinese EVs), although partially offset by lower costs of operation
* Long charging times compared to refilling a gas tank (there are some approaches which mitigate this by operating either very high-powered chargers or a battery swap model, rather than charging in-car, but these are not widely adopted)
* Relatively limited range ([https://ev-database.org/compare/electric-vehicle-longest-range 200-500 miles per charge] as of 2024, though this limitation applies to most gas vehicles as well, where 300 mile range is typical)
* Shortened range in hot weather and significantly shortened range in cold weather (although ICE vehicles also have this problem)
* Limited charging infrastructure in some places (although ICE vehicles also have this problem)
* Higher vehicle weight, and resulting higher particulate emissions (from tires, but not brakes, because EVs use of regenerative braking reduces wear on their traditional brakes)
* Reliance on various mineral and metal extraction industries in the building of batteries (yet there are also substantial minerals needed to construct ICE vehicles)
* Increased demand on electricity production
* [https://archive.is/6xmJV Lower reliability](specifically for new companies, the reliability of the fundamental technologies is much higher for EVs).

Other real pros of electric cars are also not mentioned:
* Lower costs of operation (partially offset by higher costs of purchase)
* Can "fill" them at home or while parked without having to stay with them (partially negates the "long charging times" con)
* Lower carbon footprint, and reduced dependence on the fossil fuel industry

Rapidly evolving technologies, government policies, and economic realities are changing the relevance and seriousness of these points over time. As of the publication of this strip, the "pros" of EVs do not seem to be universally convincing, as ICEs remain far more popular than EVs in most countries (EVs constitute a majority of new vehicle sales in only four countries: Norway, Iceland, Sweden and Finland). That said, EVs didn't exist as a viable industry 20 years ago, so the current reality reflects rapid and ongoing growth, suggesting that the advantages of EVs are gaining increasing recognition and understanding.

The degree of adoption is also likely to impact the viability of different vehicle types. Infrastructure in most countries has long been built around an assumption of ICEs, so things like fueling stations and ICE-qualified mechanics have traditionally been widely accessible. As EVs becoming increasingly dominant, this could shift, with EV charging infrastructure becoming easier to find than ICE fueling stations, and ICE mechanics potentially becoming more difficult to find. There's typically a certain level of inertia in the adoption of any new technology.

In the EU, [https://www.europarl.europa.eu/topics/en/article/20221019STO44572/eu-ban-on-sale-of-new-petrol-and-diesel-cars-from-2035-explained the sale of new ICE cars is banned from 2035] in an effort to move to EVs, and other jurisdictions are adopting similar policies.

Especially in the United States, this topic is highly contentious for political, economic, engineering, and {{w|Rolling coal|tribal}} reasons (as a quick look at the edit history of this page will confirm).

==Trivia==
The etymology of "gasoline" (commonly abbreviated to "gas") is disputed: it may refer to the gaseous {{w|state of matter}} as, though gasoline itself is generally liquid, it readily emits volatile vapours. Otherwise, it has been suggested to have derived from "Cazelin"/"Cazelline", originally a lamp-oil, sold by a man called {{w|John Cassell}} in the 19th century and much copied (including by the "Gazeline" brand) as the market and supply of such fuels expanded. In non-American english, the octane form of motor-fuel (i.e. non-diesel and excluding aviation fuel) is called "petrol" (derived from "petroleum", or 'oil of the rock'), with similar "electric vs petrol (vs {{w|Hybrid electric vehicle|hybrid}})" comparisons. The registered brand name "Petrol" (sold as a solvent, before being repurposed for use as vehicle fuel) could not be trademarked as it was already the common generic term for equivalent products. The unrefined crude mineral oil from which many different hydrocarbon products can be refined is still more widely known as petroleum. Vehicle fuel may now be partly or wholly composed of non-fossil-fuels to distance them from some of the traditional arguments against petrol/gas consumption, leave other considerations unchanged but possibly introduce {{w|Biofuel#Issues|further issues}}.

While ICE vehicles have, to date, proven more popular than electric equivalents, worldwide, bicycles have been outselling cars [https://www.bikeradar.com/features/bike-vs-car-the-sales-race since at least WWII].

==Transcript==
:[White Hat, with his palm raised, is talking to Cueball.]
:White Hat: Electric motors and gas engines each have their pros and cons.
:White Hat: On one hand, electric motors are cleaner and more efficient. On the other hand, electric motors are more powerful.
:White Hat: So it's hard to say which is better overall.

{{comic discussion}}

[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Cueball]]
[[Category:Engineering]]
[[Category:Climate change]]

Talk:2916: Machine

2024-04-06T22:10:53Z

172.69.134.230: page loading prblems

rather late for an april fools comic innit? also there doesn't seem to be anything exciting in this one lol, none of the usual cool exploration easter eggs, as far as i could tell at least [[Special:Contributions/172.71.178.76|172.71.178.76]] 16:41, 6 April 2024 (UTC)Erfaniom

: We're exploring crowdsourced human creativity here, in a way, so it can be a lot more interesting then Randall's exploration comics, at least for me, because i did take two years of GCSE psychology and enjoyed it. [[Special:Contributions/172.64.238.130|172.64.238.130]]

Just popped over using Chrome on Android and all I see is four "missing picture" logos spinning around, plus another down the bottom right... [[Special:Contributions/141.101.68.193|141.101.68.193]] 18:13, 6 April 2024 (UTC)
:Okay, followup: it behaves quite differently on the non mobile site. You get two entry points with red balls and yellow balls and you need to place the various gizmos to direct the balls to the correct exit point. Once enough have correctly passed to turn the red X into a green tick, you have the option to submit. If you do, once you have named your design it will be added to the grid with other submissions all of which exist to push red and yellow balls around. (if you come across "Memories of Ragnarok", that's mine) [[Special:Contributions/172.71.134.207|172.71.134.207]] 18:27, 6 April 2024 (UTC)
::The number of inputs appears to vary between 1 and 4, each of a different color, with one color-coded output for each. [[User:Claire Kholin|Claire Kholin]] ([[User talk:Claire Kholin|talk]]) 18:49, 6 April 2024 (UTC)

On the "machine" section, you see lots of "under construction cells". Perhaps this will develop as more are submitted. I notice the "under construction tape" has "DJIA" and "31415", perhaps a reference to "dow jones industrial average" and the first five digits of pi. [[User:Zeimusu|Zeimusu]] ([[User talk:Zeimusu|talk]]) 18:37, 6 April 2024 (UTC)
:Whenever someone submits a cell, it fills in one of the under construction cells. [[User:Claire Kholin|Claire Kholin]] ([[User talk:Claire Kholin|talk]]) 18:49, 6 April 2024 (UTC)

I wanted to add an image for each object, but do not have the necessary access, can someone who has access add the images that I linked in the table so they can be included? [[User:Claire Kholin|Claire Kholin]] ([[User talk:Claire Kholin|talk]]) 18:49, 6 April 2024 (UTC)

I found a discussion with some guy talking about the API at https://euphoria.leet.nu/room/xkcd/ ; this could be useful for the wiki.

<code>
[c+1] now time to try fucking with the api
[c+1] https://incredible.xkcd.com/
[userwithnoaccount] 404
[c+1] it seems there are numbered machines under incredible.xkcd.com/machine/x
[c+1] returns a grid of individual machinlets
[c+1] which are uids like 3a7af27c-5389-5dcb-b660-3feab6be2ceb
[c+1] they're stored at urls like incredible.xkcd.com/folio/3a7af27c-5389-5dcb-b660-3feab6be2ceb
[c+1] there appear to be 33 machines total
[c+1] the json it returns seems to refer to these as "versions"
[c+1] $ curl -s https://incredible.xkcd.com/machine/21 | jq ".version"
21
[c+1] there is a machine/0, but it's all null
[c+1] going to https://incredible.xkcd.com/machine/current redirects to the current machine
[c+1] $ curl -sL https://incredible.xkcd.com/machine/current | jq ".version"
35
[c+1] wait, is that the *total* number of mahcines?
[c+1] i would've thought there'd be more
[c+1] this whole think is rather esoteric
[c+1] Written in rust, too: https://rapier.rs/
[c+1] Uh oh.
https://i.hypercone.us/?v=8e283d
[c+1] HMMM
https://i.hypercone.us/?v=079f8f
[c+1] it seems there is no limit
[c+1] i've uploaded a ~50M title
</code>

[[Special:Contributions/172.70.57.146|172.70.57.146]]

Had quite a lot of fun, added a few 'successful' machines to the grid. Noted that whenever I try to use the Prism that (after a short delay) the comic-pane blanks and I need to refresh the page/get a completely new 'challenge' to start from scratch, so I'm just not using the prism at all (used most of the other items, in combination or 'just the one across the whole board', whichever seems most fun). But it doesn't seem to do what I'd like it to do, which is sort multiple colours from the same inflow into different outflow directions. Which would be ''very'' useful in a 'crossroads' situation, the general solution of directing them cross-path being too prone to random collisions. Also might be useful in the 'submitted machine grid', as I note that errors propagate, whereas adding a filter on all inputs would clean out (dispose of/send off to a valid gate?) the rogue balls. Anyway, gonna have to come back to this later when there's more time... Maybe then I'll even have something useful to add to the Explanation. [[Special:Contributions/172.70.163.31|172.70.163.31]] 19:03, 6 April 2024 (UTC)

The balls appear to be different weights. I just saw a machine that used fans to separate yellows from greens and blues in a sort of 'wheat from the chaff' manner to direct them to their correct outputs. I wonder what other hidden tricks are included. [[Special:Contributions/172.68.1.159|172.68.1.159]] 19:40, 6 April 2024 (UTC)

They're not all accepted, though it makes you think they are. Or something else more complex is going on we haven't realized yet. I made a machine that was working reliably, submitted it, and saw it on the overall grid. Reloading from a different browser I found the same location of the machine, with the same surroundings, but my machine had been replaced. It's nowhere else on the grid either. The first browser still shows it (but not after a reload with a cache clear). I'm not sure if there's some kind of "save" event that needs to happen beyond seeing your machine in the broader one, or if all user collaboration is an illusion, or if the system changes its mind about us somehow.

: Yeah, i've been seeing this too. Please tell me if you find any of my machines, images at https://i.hypercone.us/?v=22d562 , https://i.hypercone.us/?v=ad8e3a , and https://i.hypercone.us/?v=8d4d6a . I want to be one of the few to have added Catalan and Spanish to the grid. [[Special:Contributions/172.71.134.164|172.71.134.164]] 20:56, 6 April 2024 (UTC)

I've added some more observations to the page. Also, a guess which is too uncertain to put on the main page: The ball launcher for the yellows on the far left side misses a lot, and the yellow container isn't the one on the left. So I think the whole machine with crossing streams will result in the colors being sorted in their container order, and possibly have the streams combined and deposited at the bottom just above the containers. --[[Special:Contributions/172.71.147.100|172.71.147.100]] 21:07, 6 April 2024 (UTC)

has anyone seen the boat at the very bottom? [[User:Mushrooms|Mushrooms]] ([[User talk:Mushrooms|talk]]) 21:21, 6 April 2024 (UTC)

trying to see it on Firefox for Ubuntu and it just tells me to "visit xkcd.com to view" - THAT'S WHERE I AM?! Tried clearing website data (but not my entire cache) and that didn't help. Is there something I'm missing?

2840: Earth Layers

2023-10-11T18:37:04Z

172.69.134.230: /* Explanation */

{{comic
| number = 2840
| date = October 11, 2023
| title = Earth Layers
| image = earth_layers_2x.png
| imagesize = 585x627px
| noexpand = true
| titletext = The Earth's magnetic field is primarily generated by currents in the liquid outer core, though some geophysicists argue that an unexplained mismatch with models suggests that the Kinder toy contains a magnet.
}}

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

This comic reimagines the internal structure of the earth.

{| class="wikitable", style = "#22222";
! Layer
! scope="col"| Explanation

|-
! scope="row"| lithosphere/crust (50/50)
| ---
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:The layers of the Earth

:Lithosphere/crust (50/50 blend)
:Upper mantle
:Deep mantle
:Filler
:Vitreous humor
:Mechanical/HVAC layer
:Guacamole
:Cytoplasm
:Cork
:Insulation
:Seeds
:Pith
:Nougat
:Outer core
:Inner core
:Secret core
:Kinder toy capsule

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Geology]]