explain xkcd - User contributions [en]

2929: Good and Bad Ideas

2024-05-07T06:54:23Z

162.158.62.117: Soup was missing

{{comic
| number = 2929
| date = May 6, 2024
| title = Good and Bad Ideas
| image = good_and_bad_ideas_2x.png
| imagesize = 595x522px
| noexpand = true
| titletext = While it seemed like a fun prank at the time, I realize my prank fire extinguishers full of leaded gasoline were a mistake.
}}

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

This is a scatter plot comparing how good an idea sounds to how good the idea actually is. For example, leaded gasoline sounds like a good idea due to the anti-knocking effects, but is actually a bad idea due to lead toxicity. Fake prank fire extinguishers however sound bad and are bad as they can result in a dangerous situation in an emergency. Putting mold on infections sounds like a bad idea, but this could be referring to Penicillin, an antibiotic.

The title text combines leaded gasoline and a fake prank fire extinguisher into something that is worse than either. Not only is the fire extinguisher fake, it also releases flammable material onto the fire, and there is the additional lead toxicity.

{| class="wikitable"
|-
! Idea !! What it means !! How good it sounds !! How good it actually is !! Explanation
|-
|Leaded Gasoline||Adding tetraethyl lead to gasoline to increase performance||++||---||Lead is toxic. Burning the leaded gasoline in an engine releases the lead in the air. This is bad.
|-
|Bloodletting||Releasing "bad blood" from the veins||---||---||You need your blood.{{Citation needed}}
|-
|Asbestos||Mineral which does not burn and is good isolation||+++||---||Asbestos was used extensively. Sadly the microscopic fibers which make up asbestos greatly increase the risk of cancer when inhaled.
|-
|Extension cords with prongs on both ends||allows easy connection between 2 female connectors||0 (neutral)||---||Prongs on both ends would make it easier to plug the extension cord in on either side. But once plugged into an outlet, the other end becomes a serious shock hazard.
|-
|Stair Kayaking||||||||
|-
|Fake prank fire extinguishers||||||||
|-
|Always saying what you think||||||||
|-
|Replying to spammers||||||||
|-
|Solar cars||||||||
|-
|Heelies||||||||
|-
|Prequels||||||||
|-
|Transition Lenses||||||||
|-
|Cutting pizza in squares||||||||
|-
|Project Orion||Study by the U.S. government looking into nuclear pulse propulsion for spacecraft||---||-||Repeated nuclear explosions in order to move sounds bad for both the spacecraft and everything else. But there are ways to address a lot of the concerns, so it isn't as bad as it sounds.
|-
|Soup||||0 (neutral)||0 (neutral)||
|-
|Combo washer dryers||||||||
|-
|Cutting sandwiches diagonally||||||||
|-
|Diverging diamond interchanges||||||||
|-
|Toasting sandwiches||||||||
|-
|Crumple zones||||||||
|-
|Sliced bread||||||||
|-
|Pizza||||||||
|-
|Eating citrus fruit while at sea||||0 (neutral)||+++||The vitamin C present in citrus fruits prevents one from contracting {{w|Scurvy|scurvy}}.
|-
|Putting mold on infections||||||||
|-
|Wheels on luggage||||||||
|-
|Heat pumps||||||||
|-
|Laser eye surgery||||||||
|-
|Fecal transplants||||||||
|-
|}

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

{{comic discussion}}

2687: Division Notation

2022-10-19T21:47:14Z

162.158.62.117: /* Explanation */ Reworded explanation.

{{comic
| number = 2687
| date = October 19, 2022
| title = Division Notation
| image = division_notation_2x.png
| imagesize = 235x310px
| noexpand = true
| titletext = Science tip: Scientists hardly ever use the two-dot division sign, and when they do it often doesn't even mean division, but they still get REALLY mad when you repurpose it to write stuff like SALE! ALL SHOES 30÷ OFF!
}}

==Explanation==
{{incomplete|Created by a GROUP OF SCHOOLCHILDREN DIVIDED AMONGST THEMSELVES - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic pokes fun at some of the ways to write the division operation in math. In this comic, Randall has used A as the dividend (the number being divided) and B as the divisor (the number that A is divided by.)
The first two are respectively the division sign (÷) and long division symbol. (Note: the long division symbol only is used in English-speaking countries.) These methods of division are often used by school children as the first ÷ is what people learn when first learning division, and the second long division symbol is usually the first type of long division learned (it's easier to do it visually on paper that way.)

The final form of notation appears to be not a simple notation for division. Rather, it looks like a definition of a notion of division which is customized to a particular setting. This situation is likely to occur in abstract algebra, where one might have to define what "division" might mean for two elements of a mathematical object such as a group, ring, or magma. One example would be an object G, such that, for two elements A and B of G, "A divided by B" is defined as an element C such that CB=A, or alternatively as an element C such that BC=A. These definitions might differ if multiplication in G is not commutative. Furthermore, if such a C is not unique, a function F(A,B) might have to be chosen to select a unique value for "A divided by B" for each A and B. Thus, the F(A,B) in the comic might not even refer to a uniquely defined operation, but simply to the property of a function F(A,B) that it is a valid division operation on G, given some definition of division.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
A÷B and A⟌B both indicating schoolchild.
A/B left to software engineer.
A/B as in unicode ½ left to normal person or Unicode enthusiast.
A over B left to scientist.
AB^-1 left to fancy scientist.
F(A, B) such that (text getting smaller) next to oh no, run.
{{comic discussion}}

Talk:204: America

2017-11-22T05:50:36Z

162.158.62.117:

I must admit, as a "younger" reader I thought that this was a joke. [[Special:Contributions/108.162.238.221|108.162.238.221]] 18:33, 22 May 2014 (UTC)

----------------------------------------
To add some further "nuance" to this story:

As noted above, at the time of the event the "newspapers ate [the story] up". But to give another perspective on this...

At the time when this story originally broke I was living in a somewhat rural area, and this story was greeted with a shrug by virtually everyone I knew. In short, anyone familiar with being in the woods understands that they should constantly be on the alert for any abnormal behavior by a wild animal since this can be a pretty clear indication of rabies. This is particularly true of any behavior that can interpreted in any way as aggressive --especially such unexpected behavior as a (small) animal moving *towards* a human being.

Needless to say, the described behavior --both swimming and moving towards a human-- is clearly bizarre behavior for an animal like a rabbit. Among my neighbors at the time the fact Carter attempted to distance himself from the rabbit (or indeed any wild animal behaving in a similar manner) was seen simply as common sense practiced by someone like Carter; i.e. an experienced woodsman.

In short the "Killer Rabbit Attack" headlines were seen as evidence those who wrote these stories had never been near the woods in their life.
[[User:Arcanechili|Arcanechili]] ([[User talk:Arcanechili|talk]]) 13:25, 15 October 2014 (UTC)

----------------------------------------

Well, also: https://www.youtube.com/watch?v=Nvs5pqf-DMA [[Special:Contributions/162.158.62.117|162.158.62.117]]

1849: Decades

2017-06-12T22:52:55Z

162.158.62.117: Added Title text explanation and pointed out error. If error has since been fixed, feel free to put that under the Error tab. If it is not actually an error, feel free to delete the Error tab.

{{comic
| number = 1849
| date = June 12, 2017
| title = Decades
| image = decades.png
| titletext = In the 90s, our variety radio station used the tagline "the best music of the 70s, 80s, and 90s." After 2000, they switched to "the best music of the 80s, 90s, and today." I figured they'd change again in 2010, but it's 2017 and they're still saying "80s, 90s, and today." I hope radio survives long enough for us to find out how they deal with the 2020s.
}}

==Explanation==
{{incomplete|Title text not explained.}}

This comic shows, by use on a time-line, an interesting phenomenon where music, fashion, movies and culture created between the years 2000 and 2020 are not commonly grouped into the decade in which they were produced like previous decades. The comic asserts the reason for this is the lack of a single clear term to describe these decades, stating that the term "{{w|2000s}}" is ambiguous (as it could refer to the decade, century or millennium as a whole) and the terms "Aughts" and "Teens" never became the widely accepted terms for these decades.

The time-line in the comic stretches into the future (as of the time of publication) and attempts to name the 2020-2029 decade as the 20s, but does so with an uncertain question mark, presumably because it's (presently) an open question whether this dating convention will be reinstated after a 20-year pause. As the comic points out, common vernacular has managed to operate without clear terms for that grouping for 17 years, and that may have left enough of a mark on our thinking that we'll simply continue to operate in that way. There's an argument to be made grouping culture by decades is fairly arbitrary and not essential in cultural discussions. It should also be considered that that "the twenties" is still occasionally used to refer to the 1920's, and so reusing it to refer to the 2020's could be a source of confusion. It's not impossible that decade-based grouping will fall out of favor all together in the 21st century.

Despite many people pushing for terms like "aughties" and "tens", they never gained much traction among the common crowd.

The title text talks about Randall's local radio station. In the 90s, they were able to use clear decade groupings. Once the year 2000 hit, they began saying today, avoiding aughts or 2000s, which, as Randall says, never gained popular support. When 2010 hit, Randall believed they would switch their format, having left the awkwardness of the 00s. However, they kept their format to this day, finishing using teens or 10s to be confusing as well. Randall expresses interest in what change they will include in the 2020s (changing to the 20s or continuing their format), should radio last that long.

==Error==

Randall writes, presumably by mistake, "and and aughts" in the caption for this comic, instead of "and aughts". This changes the caption from his presumptive goal of "It's weird how for 20 years we stopped grouping our cultural memories by decade because "2000s" is ambiguous and "Aughts" and "Teens" never really stuck." to "It's weird how for 20 years we stopped grouping our cultural memories by decade because "2000s" is ambiguous and and "Aughts" and "Teens" never really stuck."

==Transcript==
:[A time line across the top of the box marks decades from 1960 to 2030, the labels are above the line and the ticks marking each decade are below.]

:[Label: 1960]
:60s Music; 60s Fashion; 60s Movies; 60s Culture

:[Label: 1970]
:70s Music; 70s Fashion; 70s Movies; 70s Culture

:[Label: 1980]
:80s Music; 80s Fashion; 80s Movies; 80s Culture

:[Label: 1990]
:90s Music; 90s Fashion; 90s Movies; 90s Culture

:[Label: 2000 and 2010]
:[Items grouped over two decades.]
:Fashion; Culture; Music; Movies

:[Label: 2020]
:[The text is in light grey font.]
:<font color="grey">20s Music?; 20s Fashion?; 20s Movies?; 20s Culture?</font>

:[Label: 2030]

:[Caption below the panel:]
:It's weird how for 20 years we stopped grouping our cultural memories by decade because "2000s" is ambiguous and and "Aughts" and "Teens" never really stuck.

{{comic discussion}}

Talk:1839: Doctor Visit

2017-05-19T10:46:46Z

162.158.62.117:

This comic seems relatively simpler to explain. [[User:Nialpxe|Nialpxe]] ([[User talk:Nialpxe|talk]]) 06:38, 19 May 2017 (UTC)

== 30% Cerial ==

Am I the only one who doesn't get that one?
[[Special:Contributions/172.68.51.34|172.68.51.34]] 10:08, 19 May 2017 (UTC)

I'm pretty sure the 30% cereal is a reference that the human body is made of 70% of water. [[Special:Contributions/162.158.62.117|162.158.62.117]] 10:46, 19 May 2017 (UTC)