explain xkcd - User contributions [en]

Talk:3087: Pascal's Law

2025-05-10T14:19:39Z

172.69.246.149:

I remember learning about this and thinking it was intuitive, but I didn't really think of these consequences. Maybe everybody is making powerful lifting machines for lifting cars and houses with your bare hands, rather than explaining the article, that there isn't one yet. Pascal's law basically says that if you make one end of a container of fluid X times larger, then any force exerted on the small end is multiplied by X on the large end, so you can make it near-infinite by making the small end very small. But you'll need a little more machinery added (like a gear system) if you want the distance actually moved to be higher. Actually I think that might undo the gains in force entirely. That might be how it happens, it might swap distance for force so the same work is performed.

Hey, remember that comic where Randal challenged people to fold a paper too small? This hand-makeable device could get farther on that!
[[Special:Contributions/172.70.111.110|172.70.111.110]] 21:46, 9 May 2025 (UTC)
: yes, that's how it works; the total work is constant and the hydraulic system is converting a small force over a long distance to a large force over a small distance. if you additionally want the force to be over a larger distance, you need to put more energy into the system or else you could push this machine with its own output and get free energy from nothing. really though hydraulics are just smoother, backlashless, equivalents to a gear train in the first place so you generally wouldnt need to use both. - [[User:Vaedez|Vaedez]] ([[User talk:Vaedez|talk]]) 23:37, 9 May 2025 (UTC)
:: Small tube needs to be X times as long to get same displacement. Good for linear force rather than torque. Fluid's own pressure can be the force if tube is long enough. [[Special:Contributions/172.68.55.33|172.68.55.33]] 11:41, 10 May 2025 (UTC)

As someone old enough to remember the [https://en.m.wikipedia.org/wiki/Slashdot_effect slashdot effect], I wonder if XKCD comics generate a similar effect on search engines. Though I doubt they would buckle under the weight these days. [[Special:Contributions/172.69.60.148|172.69.60.148]] 22:00, 9 May 2025 (UTC)

To whoever wrote the initial transcript, remember that we don't include the title text. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 22:06, 9 May 2025 (UTC)

I have to wonder whether he has the same disbelief of, say, levers... which allow one to move the Earth. [[User:Jordan Brown|Jordan Brown]] ([[User talk:Jordan Brown|talk]]) 23:34, 9 May 2025 (UTC)

Although some laws of physics are absolute and lead to extreme consequences, others are taught in a simplified form that can lead to wrong conclusions. For example, "Light and heavy objects fall at the same rate" can be used to prove that objects fall at the same rate on the Earth and the Moon - which is far from correct. If the Moon were somehow dropped onto the Earth, it would fall at a certain rate. The Earth dropped on the Moon would necessarily fall at the same rate. So if the Moon falling on the Earth fell at the same rate as a bowling ball, then the bowling ball would have to fall at the same rate on the Moon. When I read Heinlein's _The Rolling Stones_ as a pre-teen, where he describes things falling slower on the Moon, I applied this reasoning and concluded that Heinlein must have made a mistake. The solution to this paradox is that something as big as the Moon will not only accelerate toward the Earth, it will significantly accelerate the Earth toward it, so the Moon does not actually fall at the same rate as a bowling ball. [[User:Cphoenix|Cphoenix]] ([[User talk:Cphoenix|talk]]) 01:01, 10 May 2025 (UTC)
: I think if you stand at the shared center of mass of the Earth and Moon, that then you see the Moon falling toward the Earth according to its constant field of gravitational acceleration, as well as the Earth falling toward the Moon according to its constant field of acceleration. It was indeed confusing for me to realize this, involving visit to pages such as https://en.wikipedia.org/wiki/Gravitational_acceleration . F=Gm1m2/r^2 so if m1 is taken out you get a constant F=m1 a2 and vice versa. But I think the page says this only holds if the masses are far enough from each other to be treatable as points. [[Special:Contributions/172.68.55.47|172.68.55.47]] 11:57, 10 May 2025 (UTC)

Besides, isn't it better to just ''believe'' in Pascal's Law if it offers a reward of near-infinite force?
[[User:StapleFreeBatteries|StapleFreeBatteries]] ([[User talk:StapleFreeBatteries|talk]]) 04:58, 10 May 2025 (UTC)

Could this be referencing or inspired by this recent paper talking about the use of hydraulics to build pyramids? https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0306690 [[Special:Contributions/172.68.234.169|172.68.234.169]] 08:52, 10 May 2025 (UTC)

It could be noted that simple machines can multiply forces more or less arbitrarily, but only up to what the machine itself can withstand. Many "why didn't the ancients do that?" can be answered with "bronze kind of sucks". [[Special:Contributions/172.69.246.149|172.69.246.149]] 14:19, 10 May 2025 (UTC)

Talk:3071: Decay Chain

2025-04-03T05:32:58Z

172.69.246.149:

... should have gone down to the 5S. That was really rock bottom... [[Special:Contributions/172.70.114.36|172.70.114.36]] 01:53, 3 April 2025 (UTC)
: My old SE was a real workhorse. Small enough to comfortably use in one hand, power button on the top so I don't have to worry about turning it off when gripping it, headphone jack, black background on the reboot screen, and twice as much storage as my current iphone 7. It kept working until the screen cracked and glass was peeling out of the screen, and several months beyond that, when the screen just went blank and refused to turn on. [[User:Firestar233|guess who]] ([[User talk:Firestar233|if you desire conversing]] | [[Special:Contributions/Firestar233|what i have done]]) 05:10, 3 April 2025 (UTC)

No april fools' comic? Sad. [[User:Onestay|Onestay]] ([[User talk:Onestay|talk]]) 01:58, 3 April 2025 (UTC)

:Takes some time. Might still be one.--[[User:Bb777|me, hi]] ([[User talk:Bb777|talk]]) 02:18, 3 April 2025 (UTC)

:Yeah, escape speed was late for 18 days, maybe the new interactive comic will be the same [[User:Aprilfoolsupdate!|Aprilfoolsupdate!]] ([[User talk:Aprilfoolsupdate!|talk]]) 05:06, 3 April 2025 (UTC)

A quick search for "newest iPhone" gave me that 16 (various models) is the newest. That is, if it's newer than 15. [[Special:Contributions/172.68.15.141|172.68.15.141]] 04:39, 3 April 2025 (UTC)

Most stars only produce Bell rotary phones, perhaps producing touch tone or even cordless phones briefly as they move off the main sequence. Massive stars can produce up to Nokia phones, but that's the final stage that stars can produce in their normal lifespan. All smartphones are produced in supernova. [[Special:Contributions/172.69.246.149|172.69.246.149]] 05:32, 3 April 2025 (UTC)

Talk:3071: Decay Chain

2025-04-03T05:32:05Z

172.69.246.149:

... should have gone down to the 5S. That was really rock bottom... [[Special:Contributions/172.70.114.36|172.70.114.36]] 01:53, 3 April 2025 (UTC)
: My old SE was a real workhorse. Small enough to comfortably use in one hand, power button on the top so I don't have to worry about turning it off when gripping it, headphone jack, black background on the reboot screen, and twice as much storage as my current iphone 7. It kept working until the screen cracked and glass was peeling out of the screen, and several months beyond that, when the screen just went blank and refused to turn on. [[User:Firestar233|guess who]] ([[User talk:Firestar233|if you desire conversing]] | [[Special:Contributions/Firestar233|what i have done]]) 05:10, 3 April 2025 (UTC)

No april fools' comic? Sad. [[User:Onestay|Onestay]] ([[User talk:Onestay|talk]]) 01:58, 3 April 2025 (UTC)

:Takes some time. Might still be one.--[[User:Bb777|me, hi]] ([[User talk:Bb777|talk]]) 02:18, 3 April 2025 (UTC)

:Yeah, escape speed was late for 18 days, maybe the new interactive comic will be the same [[User:Aprilfoolsupdate!|Aprilfoolsupdate!]] ([[User talk:Aprilfoolsupdate!|talk]]) 05:06, 3 April 2025 (UTC)

A quick search for "newest iPhone" gave me that 16 (various models) is the newest. That is, if it's newer than 15. [[Special:Contributions/172.68.15.141|172.68.15.141]] 04:39, 3 April 2025 (UTC)

Most stars only produce Bell rotary phones, perhaps producing touch tone or even cordless phones. Massive stars can produce up to Nokia phones, but that's the final stage that stars can produce in their normal lifespan. All smartphones are produced in supernova. [[Special:Contributions/172.69.246.149|172.69.246.149]] 05:32, 3 April 2025 (UTC)

3054: Scream Cipher

2025-02-27T04:21:50Z

172.69.246.149: /* Trivia */ }}

{{comic
| number = 3054
| date = February 21, 2025
| title = Scream Cipher
| image = scream_cipher_2x.png
| imagesize = 287x416px
| noexpand = true
| titletext = AAAAAA A ÃA̧AȂA̦ ǍÅÂÃĀÁȂ AAAAAAA!
}}

==Explanation==
{{incomplete|Created by A ÃA̧ȂÁAǍẢÂA̋ ȦÅĀ - Need to add more notes for the other cipher characters. Do NOT delete this tag too soon.}}
A {{w|Cipher}} is a method of encryption, where characters, or sometimes words, are substituted for other characters in a set pattern, allowing for arbitrary strings to be enciphered using it. The complexity and strength of ciphers varies, from {{w|one-time pads}} and (historically) {{w|enigma machine|Enigma}} as stronger and more complex, to {{w|substitution ciphers}} as some of the weakest and least complex, where each character is simply given a set different symbol to represent it in the cipher.

This comic uses a substitution cipher, where all the letters of the English Alphabet are represented using the letter "A", with different {{w|diacritical marks}} to define the differences. See details about the 25 marks in the [[#Trivia|Trivia section]] below. This kind of cipher is often used on a recreational basis by children or casual enthusiasts, the similarity of the letters increasing the obscurity of the content and the skill or technology required for use, but there is also significant impracticality, as not only are substitution ciphers the easiest to break, but also the similarities in the letters do make the cipher hard to read and easy to misread, and the detail in the diacritical marks makes it easy to draw the "A"s incorrectly or ambiguously, potentially leading to [[3003: Sandwich Helix|part of the message being lost]]. This was our experience in the comments section of this very article, where one person implemented translator functions alongside another person crafting a message that failed to translate. However, the logic behind the code is mostly visual similarity, and if attentive to connecting concepts between the Latin and scream cipher alphabet, it could be quickly learned and translated in a glance.

It's named "Scream Cipher" (as a pun on {{w|stream cipher}}s, commonly used in computing) because the written form of a scream is often a long string of As, possibly with some other characters at the end (and often an exclamation point for emphasis), such as "Aaaaaah!" or "Aaaaaaagh!". The name may or may not be a reference to IBM's {{w|Scream_(cipher)|Scream cipher}} published in 2002.

In the comic, [[Cueball]] texts the ciphered version for the plaintext "HELLO", and [[Megan]] responds with that for "HI". The title text deciphers to "AAAAAA A SCARY MONSTER AAAAAAA!"

Another recent comic featuring all "A"s was [[2957: A Crossword Puzzle]].

Diacritics was also the main theme in [[1647: Diacritics]] (of course) and was previously also mentioned in [[1209: Encoding]] and in [[1857: Emoji Movie]] where they have an important part of the pun, and is mentioned in one point of the list in [[1957: 2018 CVE List]].

==Worked example==

Say we want to encode "Scream" in the Scream Cipher. First we would need to split out word into the letters, so S, C, R, E, A, M.

The first letter is S, so if we go to S in the table S is shown to become to Ã, C similarly becomes A̧, R becomes Ȃ, E corresponds to Á, A is the main letter so A is unchanged to A, and M becomes Ǎ. If we then write them again in order, we find SCREAM becomes ÃA̧ȂÁAǍ.

To turn cipher text back into normal text, the process is repeated in reverse. To translate A̧ẢA̯A̰ÁȂ, we go to A̧ in the table and find A̧ becomes C. Ả similarly becomes I, A̯ becomes P, A̰ becomes H, Á becomes E, and Ȃ becomes R. If we write the letters in order, we see that A̧ẢA̯A̰ÁȂ becomes CIPHER.

Text can be automatically translated using any of the following community implimentations:
* The first known translator hosted on [https://github.com/Reginald-Gillespie/ScreamCipher GitHub Pages].
* A more bare-bones [https://github.com/matthewpwatkins/scream-cipher/ implimentation] hosted on netlify.
* A terminal [https://github.com/klanderfri/ScreamCipher/ implimentation].

==Transcript==
:[The top of the panel has the 26 letters of the alphabet written, each followed by a hyphen and the letter "A" with a unique diacritical mark for each. "A - A" is the only letter in the top row, and the only one where that A on the right side doesn't have a diacritic. The next 25 is sorted in a 5 by 5 grid, with the first five letters after A in the first column, then the next 5 in the second column and so on:]
:{|
|A - A
|-
|B - Ȧ
|G - A̋
|L - Ă
|Q - A̤
|V - À
|-
|C - A̧
|H - A̰
|M - Ǎ
|R - Ȃ
|W - Ȁ
|-
|D - A̱
|I - Ả
|N - Â
|S - Ã
|X - A̽
|-
|E - Á
|J - A̓
|O - Å
|T - Ā
|Y - A̦
|-
|F - A̮
|K - Ạ
|P - A̯
|U - Ä
|Z - Ⱥ
|}
:[Beneath these letters we see Cueball and Megan typing on their phones, Cueball with two hands and Megan with one hand, small lines indicating the movement of their hands. Cueball and Megan is turned towards each other but with more separation than if they were engaged in normal discussion. They both look down at their phones not towards each other. The text they type is shown above their phone with a line starting in a starburst at the top of their phones going up the to the text.]
:Cueball's phone: A̰ÁĂĂÅ
:Megan's phone: A̰Ả

:[Caption below the panel:]
:In the '''''Scream Cipher''''', messages consist of all As, with different letters distinguished using diacritics.

==Trivia==
The {{w|Unicode}} names of the characters in the cipher are as follows:

{|class="wikitable"
! colspan=2 | Input !! colspan=3 | Substitution
|-
! Plain !! Unicode description !! Cipher !! Unicode description(s) !! Notes
|-
| A || U+0041 LATIN CAPITAL LETTER A || {{w|A}} || '''U+0041 LATIN CAPITAL LETTER A || Unadorned base character
|-
| B || U+0042 LATIN CAPITAL LETTER B || {{w|Ȧ}} || '''U+0226 LATIN CAPITAL LETTER A WITH {{w|Dot (diacritic)|DOT}} ABOVE || A with one dot over it, which can indicate a single change in math and science. Phonetic symbol for low central vowel.
|-
| C || U+0043 LATIN CAPITAL LETTER C || A̧ || U+0041 LATIN CAPITAL LETTER A, '''U+0327 {{w|Combining Diacritical Marks|COMBINING}} {{w|Cedilla|CEDILLA}}''' || Cedilla is often attached to a 'c', as in "français", as well as starting with 'c' itself. Appears similar to Ą (U+0104, A with ogonek) used in many language to denote a nasal a sound and in Polish to denote a nasal o sound, however the two can be distinguished by the direction of the diacritic.
|-
| D || U+0044 LATIN CAPITAL LETTER D || A̱ || U+0041 LATIN CAPITAL LETTER A, '''U+0331 COMBINING MACRON BELOW''' || Some see the lower bar as similar to the lower edge of the D.
|-
| E || U+0045 LATIN CAPITAL LETTER E || {{w|Á}} || '''U+00C1 LATIN CAPITAL LETTER A WITH ACUTE || Many words have an acute e, as in "fiancé".
|-
| F || U+0046 LATIN CAPITAL LETTER F || A̮ || U+0041 LATIN CAPITAL LETTER A, '''U+032E COMBINING BREVE BELOW''' || The breve adds a second line to the A, much like how an F has two lines.
|-
| G || U+0047 LATIN CAPITAL LETTER G || A̋ || U+0041 LATIN CAPITAL LETTER A, '''U+030B COMBINING {{w|Double acute accent|DOUBLE ACUTE}} ACCENT''' || Adds two acutes to a letter.
|-
| H || U+0048 LATIN CAPITAL LETTER H || A̰ || U+0041 LATIN CAPITAL LETTER A, '''U+0330 COMBINING TILDE BELOW''' || The low tilde has horizontal ink in the middle that moves vertical toward the sides, like an H.
|-
| I || U+0049 LATIN CAPITAL LETTER I || {{w|Ả}} || '''U+1EA2 LATIN CAPITAL LETTER A WITH HOOK ABOVE || The hook almost looks like half of a circle, and the lowercase letter I (i) has a circular shape (known as a tittle) above it.
|-
| J || U+004A LATIN CAPITAL LETTER J || A̓ || U+0041 LATIN CAPITAL LETTER A, '''U+0313 COMBINING COMMA ABOVE''' || The comma symbol looks like a small letter 'J' in some fonts
|-
| K || U+004B LATIN CAPITAL LETTER K || Ạ || '''U+1EA0 LATIN CAPITAL LETTER A WITH DOT BELOW || 
|-
| L || U+004C LATIN CAPITAL LETTER L || {{w|Ă}} || '''U+0102 LATIN CAPITAL LETTER A WITH {{w|Breve|BREVE}} ||
|-
| M || U+004D LATIN CAPITAL LETTER M || Ǎ || '''U+01CD LATIN CAPITAL LETTER A WITH {{w|caron|CARON}} || The top-centered caron is the same shape as the top center of the M.
|-
| N || U+004E LATIN CAPITAL LETTER N || {{w|Â}} || '''U+00C2 LATIN CAPITAL LETTER A WITH CIRCUMFLEX || The lowercase letter 'n' also looks like a circumflex in some scripts. The circumflex peak mirrors the peak at the top left of the N.
|-
| O || U+004F LATIN CAPITAL LETTER O || {{w|Å}} || '''U+00C5 LATIN CAPITAL LETTER A WITH RING ABOVE || The symbol contains the letter 'O'. In Scandinavian languages like Swedish, this combination of 'O' and 'A' is a letter unto itself, mostly used in words where a long 'a' sound has acquired a more 'o'-like sound.
|-
| P || U+0050 LATIN CAPITAL LETTER P || A̯ || U+0041 LATIN CAPITAL LETTER A, '''U+032F COMBINING INVERTED BREVE BELOW''' || Refer to R: P also has a curve at the top center, but is encoded with one below.
|-
| Q || U+0051 LATIN CAPITAL LETTER Q || A̤ || U+0041 LATIN CAPITAL LETTER A, '''U+0324 COMBINING DIAERESIS BELOW''' || The two dots below the baseline reflect the two times Randall's Q touch the baseline. In the Orthographies of Spanish, Catalan, French and Galician, the grapheme 'qu' normally represents a single sound, before vowels 'e' and 'i'. In the few exceptions where the 'u' is pronounced, a diaeresis is added to it.
|-
| R || U+0052 LATIN CAPITAL LETTER R || Ȃ || '''U+0202 LATIN CAPITAL LETTER A WITH {{w|Inverted breve|INVERTED BREVE}} ||
The inverted centered top curve mirrors the curve at the top center of an R.
|-
| S || U+0053 LATIN CAPITAL LETTER S || {{w|Ã}} || '''U+00C3 LATIN CAPITAL LETTER A WITH TILDE || Tilde looks like a sideways 'S'.
|-
| T || U+0054 LATIN CAPITAL LETTER T || {{w|Ā}} || '''U+0100 LATIN CAPITAL LETTER A WITH {{w|Macron (diacritic)|MACRON}} || The macron looks like the top horizontal line in the letter 'T'
|-
| U || U+0055 LATIN CAPITAL LETTER U || {{w|Ä}} || '''U+00C4 LATIN CAPITAL LETTER A WITH DIAERESIS || The {{wiktionary|trema#Noun|two dot mark}} is used in many words in languages like German, Finnish and Swedish, with 'Ä' used as in "{{w|Die_Ärzte|Ärzte}}". As a true {{wiktionary|diaeresis#Usage notes|diaresis}}, it often indicates a vowel that is distinct from neighbouring vowels, rather than part of a {{w|Digraph (orthography)|digraph}} or longer phoneme. As a modifier of the vowel itself, as with the germanic/nordic languages, it is more properly called an 'umlaut' and may change a back vowel into a front vowel, though the two terms are often used interchangably.
|-
| V || U+0056 LATIN CAPITAL LETTER V || {{w|À}} || '''U+00C0 LATIN CAPITAL LETTER A WITH GRAVE || Grave has the letter 'V' in it, as well as being half of its shape.
|-
| W || U+0057 LATIN CAPITAL LETTER W || Ȁ || '''U+0200 LATIN CAPITAL LETTER A WITH {{w|Double grave accent|DOUBLE GRAVE}} || The letter 'W' is visually two copies of the letter 'V'
|-
| X || U+0058 LATIN CAPITAL LETTER X || A̽ || U+0041 LATIN CAPITAL LETTER A, '''U+033D COMBINING X ABOVE''' || The symbol contains the letter 'X'.
|-
| Y || U+0059 LATIN CAPITAL LETTER Y || A̦ || U+0041 LATIN CAPITAL LETTER A, '''U+0326 COMBINING COMMA BELOW''' || The comma mimics the vertical "tail" of the Y.
|-
| Z || U+005A LATIN CAPITAL LETTER Z || {{w|Saanich_dialect#Writing_system|Ⱥ}} || '''U+023A LATIN CAPITAL LETTER A WITH STROKE || The stroke through the letter A resembles the diagonal stroke of a capital "Z"
|}

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Language]]
[[Category:Cryptography]]
[[Category:Unicode]]
[[Category:Smartphones]]

Talk:2966: Exam Numbers

2024-07-31T20:18:47Z

172.69.246.149: i spent way too much time researching this lmao

pre-algebra: 4, calculus: pi^2 / 4 (about 2.467), physics: cosmological constant: depends on how you measure it [[Special:Contributions/162.158.167.48|162.158.167.48]] 18:11, 31 July 2024 (UTC)

Game theory: -5x10⁶ (maybe helpful, maybe not... just be thankful I didn't include an ''i'' factor in there somewhere...) [[Special:Contributions/172.70.162.185|172.70.162.185]] 18:20, 31 July 2024 (UTC)

Could somebody reformat all the math here in whatever LaTeX plugin this wiki uses? --[[Special:Contributions/162.158.222.102|162.158.222.102]] 18:35, 31 July 2024 (UTC)
:Probably not, because the MathML here is broken. But, also, nothing I see requires anything particularly complicated, it can all stay in fairly straightforward (standardly formatted) text. [[Special:Contributions/141.101.98.224|141.101.98.224]] 18:44, 31 July 2024 (UTC)
I had to look up "TREE(3)." Seriousness aside, I think the largest number would be the astrological sign 1 that has its end_points_ as galaxy clusters.[[Special:Contributions/172.68.245.184|172.68.245.184]] 19:26, 31 July 2024 (UTC)

Infinity is _not_ a number. [[User:Dúthomhas|Dúthomhas]] ([[User talk:Dúthomhas|talk]]) 19:39, 31 July 2024 (UTC)

If infinity _is_ a number, it might be a possible solution to the game theory question. The average of any set of numbers that includes infinity is infinity, and infinity + 10 is still infinity. I probably wouldn't try that in most classes, but a game theory professor might approve "gaming" the system, as it were.
:If I would prefer no-one (else) to win, I might submit -∞ as my answer. [[Special:Contributions/172.70.90.74|172.70.90.74]] 20:13, 31 July 2024 (UTC)

Infinity is absolutely not a number, and is the one answer I would mark as unambiguously wrong for the last one. Just say TREE(G_64) or something. [[Special:Contributions/162.158.154.31|162.158.154.31]] 20:15, 31 July 2024 (UTC)

I did a bit of a deep dive into wikipedia and the googology wiki and the answer to the last question depends on a few things (along with assuming ZFC). If transfinite ordinals count as numbers, then those at the end of {{w|List of large cardinal properties}} take the cake (if i'm reading it right). Otherwise, something based off [https://googology.fandom.com/wiki/Rayo%27s_number Rayo's number] is the best googologists have come up with so far. [[Special:Contributions/172.69.246.149|172.69.246.149]] 20:18, 31 July 2024 (UTC)Bumpf