explain xkcd - User contributions [en]

2280: 2010 and 2020

2020-03-16T02:36:56Z

108.162.229.156: a little over-wordy but I feel it needs something just to make clear that Not Everybody Is Going To Die Horribly From Coronavirus

{{comic
| number = 2280
| date = March 13, 2020
| title = 2010 and 2020
| image = 2010_and_2020.png
| titletext = 2030: "I just bought a house for one bitcoin. No, it's the equivalent of a dollar. Houses are often transferred for a nominal fee because the buyer is taking responsibility for containing the holo-banshees in the attic."
}}

==Explanation==
{{incomplete|Created by a SARS-CoV-2 VIRUS. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic is the sixth comic in a [[:Category:COVID-19|series of comics]] (with at least six in a row) about the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} - {{w|SARS-CoV-2}}.

[[White Hat]], who lives in 2010, and [[Cueball]], who lives in 2020, are in contact with each other via some kind of time travel. White Hat wants to learn about life in 2020 and is particularly interested in {{w|bitcoin}}, a decentralized {{w|cryptocurrency}} which was released in 2009, and whether it had become an acceptable currency. Cueball answers that bitcoin still exists, and that he just bought a bottle of {{w|hand sanitizer}} for the price of one bitcoin. White Hat probably assumes that bitcoin is a widely accepted currency worth a few dollars, and thinks that the situation is "normal". (In April 2010, one bitcoin was worth about 14 cents.)

At the time of this comic, the SARS-CoV-2 virus, commonly known as "the coronavirus", is spreading around the world, causing thousands of people to die (although relatively few compared to the number of people that have gotten better) and billions to panic. This increased the demand for hygiene products, including hand sanitizers, and therefore their price has increased. It also triggered a panic on financial markets, including severe devaluation of the infamously volatile bitcoin. Despite the crash, one bitcoin was still worth about $5,400 on the day this strip was published, not a few dollars. Therefore, buying a hand sanitizer for one bitcoin is not as normal as White Hat assumes.

The price of hand sanitizer has not reached the price of a bitcoin (yet), although some people on sites such as {{w|Amazon.com}} are attempting to sell it for ludicrous amounts and there are attempts by Amazon, eBay, and other selling platforms, as well as potential legislation, aimed at curtailing such {{w|price gouging}}.

The title text claims that, in 2030, bitcoin will again be worth about one dollar, but houses will also be worth only one dollar due to the difficulty inherent in containing "holo-banshees" in the attic. What a holo-banshee is is not explained, but one can guess as to what it might mean. "Holo" is generally short for {{w|hologram}} and typically denotes some kind of 3D looking digital visual form, and a "{{w|banshee}}" is a mythological wailing creature or spirit. So even if not a physical object, constant shrieking would be undesirable.

If holo-banshees were present in every house, then a person would have no choice but to live in a house with them (or live somewhere that is not a house, or die). However, since the text specifically states that they are "in the attic", houses without attics would not have holo-banshees and would sell for much higher prices. Therefore, it might be only the houses with attics that are so cheap. (In this situation, a profit could be made by renovating houses to remove the attics or by tearing down houses with attics and building new ones without attics to replace them. However, doing so might be illegal due to laws either meant to protect the holo-banshees or meant to keep them from escaping, or impractical due to the interference of the holo-banshees themselves.)

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[White Hat and Cueball are walking to the right of the panel. There is a gray outline around Cueball, indicating he is from the future]
:White Hat: What are things like ten years from now in 2020?
:White Hat: We have this new "bitcoin" thing — does it ever catch on and become normal?

:[A frameless panel, with White Hat and Cueball still walking to the right.]
:Cueball: It's still around. I just bought a bottle of hand sanitizer for one bitcoin.

:[A regular panel, with them continuing to walk]
:White Hat: Cool, that sounds pretty normal.
:Cueball: Well, here's the thing...

{{comic discussion}}

[[Category:COVID-19]]
[[Category: Comics featuring Cueball]]
[[Category: Comics featuring White Hat]]
[[Category: Time travel]]

2063: Carnot Cycle

2020-03-13T13:12:14Z

108.162.229.156: /* Explanation */ The Carnot explanation was a total mess.

{{comic
| number = 2063
| date = October 24, 2018
| title = Carnot Cycle
| image = carnot_cycle.png
| titletext = The Carnot cycle is more properly known by its full title, the "Carnot-Tolkien-Wagner Ring Cycle."
}}

==Explanation==

This comic shows a {{w|Pressure–volume diagram}} which is used in this case for a {{w|Carnot cycle}}, a theoretical thermodynamic cycle covered in most thermodynamics classes which looks a lot like the figure drawn. The most common example of a (suboptimal) Carnot cycle is the {{w|Heat_pump_and_refrigeration_cycle|vapor compression cycle}} used in {{w|Refrigerator|refrigerators}}. However in this case, [[Randall]] has replaced the labels of the 4 stages of the real Carnot cycle with new ones.

Pressure–volume diagrams were first developed to understand the efficiency of steam engines and plot the change of pressure ''p'' with respect to volume ''V'' for a specific process. The process forms a cycle and the amount of energy involved can be estimated by the area under the curve on the chart. The Carnot cycle describes the ideal efficiency that such an engine can achieve during the conversion of heat into work, or vice versa like in a refrigeration system. The real steps are called (explained in short):
#'''Isothermal expansion''' (An external heat source causes an increase of volume and an antiproportional lowering of pressure, driving the motor. It's more efficient if this step is performed slowly.)
#'''Isentropic expansion''' (The volume of the gas goes down further while the pressure decreases dramatically, as the external heat source is now absent, transforming heat directly into work, lowering the Temperature. This step is more efficient, if it goes quicker.)
#'''Isothermal compression''' (External cooling and a small amount of work from another part of the machine decreases the volume of the gas and leads to the last step:)
#'''Isentropic compression''' (Now the gas is sharply compressed, using part of the work from step two to return the gas to the beginning of step one, raising the Temperature back up.)

An isothermal process is a change of a system, in which the temperature remains constant. In this diagram the volume increases (expansion) or decreases (compression). The term isentropic describes a lossless process where no heat leaves the gas, here the increased volume only causes a further decrease in pressure; it is also called adiabatic process and is the thing which warms air when you compress it quickly. Isentropic means "doesn't cause the heat death of the universe.", which is a rare thing.

The prefix ''iso-'' is derived from the Ancient Greek word ''ísos'' which translates to ''equal'' and used widely in modern days in science like here to indicate a process at the same temperature (-thermal) which is not shown in the graph. The prefix ''is-'' to the term {{w|Entropy|entropy}} is used because isoentropic sounds stupid.

In the comic, the cycle also has two phases of expansion followed by two phases of contraction (or "decline"), but the names of steps one to three are replaced with other words beginning with the prefix "iso-" meaning same or equal, and the factors that are held constant are absurd.

Each step in this comic is explained below:

'''1. Isometric expansion.''' When heated, the gas becomes larger due to increasing volume

Isometric (literally "equal dimensions") can refer to a property or process that is symmetrical in all dimensions (i.e. the gas is expanding radially) or to a [[wikipedia:Isometric process | type of thermodynamic process]] where volume is held constant but temperature is free to vary, the exact opposite of the first step in the real Carnot cycle. Additionally, the comic text uses a circular argument (become larger due to increasing volume).

In mathematics, an {{w|isometric mapping}} (between metric spaces) is a map that keeps all the distances intact. If we measure the distance the same way throughout the cycle, then isometric expansion (or for that matter, isometric compression) is not really an expansion (or a compression).

'''2. Isotonic expansion.''' The gas expands further due to dark energy while percent milkfat remains constant.

{{w|Isotonic}} is a descriptor commonly associated with sports drinks (and not thermodynamics), which contain similar concentrations of salt and sugar as in the human body. {{w|Dark energy}} is hypothesized to be a cause for the expansion of the universe, which obviously isn't relevant to thermodynamics.(Yet.) The [https://hypertextbook.com/facts/2002/AliciaNoelleJones.shtml density of milk] depends on milkfat and solids-non-fat, which includes lactose. Fortified milk has increased solids-non-fat but the same percentage of milkfat, resulting in increased calories and an increased density. So the fortification of milk results in increased calories, possibly referred to as dark energy, and a contraction, as less space is needed for 1 kg of milk. However, this explanation does not match the expansion suggested in the comic.

Later Randall again combined dark energy (and also dark matter) with milkfat in [[2216: Percent Milkfat]].

'''3. Isopropyl compression.''' While inflation is held constant, the gas contracts due to tightening interest rates.

{{w|Isopropyl alcohol}} is commonly used for cleaning. Inflation and contraction could refer to changes in gas volume, but the reference to {{w|interest rate}}s puts them in the context of {{w|macroeconomics}}. Raising ("tightening") interest rates tends to reduce {{w|inflation}} and/or "contract" the economy. High interest rates are a feature of the third stage (recession) of the {{w|Juglar cycle}}. In economics (and other sciences) to better understand model parameter relations, some parameter may be held constant in theory. This could refer to the {{w|Fisher equation}}. Holding one parameter constant is also done in the Carnot cycle (for a physical parameter): not only in theory but also in practice! (In free market economies the inflation cannot be directly held constant).

But inflation may also refer to ''dark energy'' mentioned at the ''isotonic expansion'' section above. {{w|Inflation (cosmology)|Inflation}} in cosmology is a theory of the exponential expansion of space in the early universe, an effect associated with the "accelerating universe" and for which findings the 2011 Nobel Prize in Physics was given. The NationalGeographic blog entry [https://blog.nationalgeographic.org/2011/10/12/nobel-prize-in-physics-2011-the-accelerating-universe/ Nobel Prize in Physics 2011 – The Accelerating Universe] explains that "...Today, most physicists, influenced by inflation, would ... call it dark energy."

'''4. Decline and fall.''' The gas diminishes and goes into the West while remaining Galadriel, completing the cycle.

{{w|Galadriel}} is a character in ''{{w|The Lord of the Rings}}''. She is one of the leading {{w|Elf (Middle-earth)|elves}}, a race that in the time of the book is said to be dwindling (in number and importance) in {{w|Middle Earth}} and migrating westward to {{w|Valinor}}. Galadriel is one of the last elves to leave, after successfully resisting temptation to take the One Ring and become an all-powerful queen who dominates Middle-earth, instead saying "I will diminish, and go into the West, and remain Galadriel." The title may be a reference to {{w|Edward Gibbon}}'s 18th century masterpiece ''{{w|The History of the Decline and Fall of the Roman Empire}}'', or to the novel ''{{w|Decline and Fall}}'' by {{w|Evelyn Waugh}} (which is itself a reference to Gibbon's book). This stage is present in the cycle because in the real cycle, at this stage, volume of the gas decreases without exchange of heat. It is the last stage after which the gas has its original value of variables, thus completing the cycle.

The title text refers to {{w|Richard Wagner}} and {{w|J.R.R Tolkien}}. Wagner's ''{{w|Der Ring des Nibelungen|Ring Cycle}}'' consists of four operas. Tolkien wrote ''{{w|The Lord of the Rings}}'', which some have [[wikipedia:J. R. R. Tolkien's influences#Wagnerian_influences|suggested]] was inspired by Wagner's Ring. Their works are known as {{w|literary cycle}}s.

==Transcript==
:[A cartesian plot in the first quadrant with axes labeled "P" on the vertical axis and "V" on the horizontal axis, with a rhombus-shaped set of four points with arrows between them.]
:[Caption above the graph:]
:The four stages of the
:'''Carnot Cycle'''

:[The first line starts at the top-left point and goes right and slightly downwards to the next point. The label is:]
:'''1. Isometric Expansion'''
:When heated, the gas becomes larger due to increasing volume

:[The next line starts at the last point and goes downwards and a little to the right.]
:'''2. Isotonic Expansion'''
:The gas expands further due to dark energy while percent milkfat remains constant

:[The next line starts at this last point and goes to the left and slightly upwards.]
:'''3. Isopropyl Compression'''
:While inflation is held constant, the gas contracts due to tightening interest rates

:[The last line goes upwards and slightly to the left, returning to the first point.]
:'''4. Decline and Fall'''
:The gas diminishes and goes into the west while remaining Galadriel, completing the cycle

{{comic discussion}}

[[Category:Line graphs]]
[[Category:Physics]]
[[Category:LOTR]]

2277: Business Greetings

2020-03-06T08:46:28Z

108.162.229.156: Add category "No title text"

{{comic
| number = 2277
| date = March 6, 2020
| title = Business Greetings
| image = business_greetings.png
| titletext =
}}

==Explanation==
{{incomplete|Created by an EYEBALL LICKER. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

The COVID-19 coronavirus is a big deal{{Citation needed}}. As a reaction, people are refraining from personal contact. This leads to conflicts with customs in the workplace - eg shaking hands at the beginning.

This comic parodies that by claiming people are reacting to the virus by avoid "licking eyeballs" at starts of meeting. Virus or not, it is not normal lick eyeballs at meetings{{Citation needed}}. However, eyeball licking was a teen fad in Japan and other countries during the early 2000s, suggesting something else is going on{{Citation needed}}.

This comic does not appear to have a title-text. It is possible that this is to prevent further spread of the coronavirus {{Citation needed}}. Absence of title-text is so unusual, that broke at least one xkcd client ([https://play.google.com/store/apps/details?id=com.floern.xkcd Browser for xkcd by Floern]).

==Transcript==

[Single frame where Beret Guy is standing on the left, with three people sitting at a table to the right (from left to right: Ponytail, Hairy and Hairbun)]

Beret Guy: I don't think we should overreact to the coronavirus, but it might be time to put an end to the custom of starting business meetings by everyone licking each other's eyeballs.

Hairy: I'll miss the human contact, but that's fair.

Hairbun: Gotta change with the times.

{{comic discussion}}

[[Category:No title text]]

Talk:1414: Writing Skills

2014-08-29T08:13:46Z

108.162.229.156:

Scoring higher on grammar and spelling tests could be related to constantly using the English language - however I think an opportunity was missed with this one: the correlation between kids who have access to texting devices and kids who have access to good schooling and tutoring.

Is the double "writing" at the beginning of the title text a typo, or has it a meaning? (Non-native english here, so I probably missed something). [[Special:Contributions/108.162.229.156|108.162.229.156]] 08:13, 29 August 2014 (UTC)

Talk:1393: Timeghost

2014-07-11T08:12:39Z

108.162.229.156:

A lot of the facts seem to fit information that sites like http://you.regettingold.com/ would provide. But I'll leave it up to someone else to work out the dates of everything (except for the imminent and possibly eerie deaths of the strip characters) being referenced, and thus what ages Randall is assuming the various cohorts are... [[Special:Contributions/141.101.99.233|141.101.99.233]] 04:58, 11 July 2014 (UTC)

''Forrest Gump'' the book - 1986

''Forrest Gump'' the movie - 1994

Vietnam War - 1955 to 1975

Keanu Reeves - born 1965 (age 49)

''The Simpsons'' season 5 - 1993 [[User:Dude1818|Dude1818]] ([[User talk:Dude1818|talk]]) 05:15, 11 July 2014 (UTC)

I'm sure you all remember [[1108:_Cautionary_Ghost|Cautionary Ghost]]; there's got to be a lot of those around in the xkcd universe... [[Special:Contributions/108.162.231.73|108.162.231.73]] 07:23, 11 July 2014 (UTC)

I don't know enough about the English usage of the term to see the connection, but could this be a play on "zeitgeist", seeing how it is a literal translation of the word? [[Special:Contributions/103.22.200.115|103.22.200.115]] Tobl

Maybe it is just me, but I don't see the characters' deaths as imminent. In the first panel, Megan is not suprised to see that ghost and can even identify it easily. So my guess is that she previously met the ghost "some time" before, but she (obviously) doesn't like to know how much time she has left to live. [[Special:Contributions/108.162.229.156|108.162.229.156]] 08:12, 11 July 2014 (UTC)