# Factual Questions **URL:** https://boards.straightdope.com/c/factual-questions/9.md?page=22 [Latest](https://boards.straightdope.com/latest.md) · [Categories](https://boards.straightdope.com/categories.md) · [Tags](https://boards.straightdope.com/tags.md) **Page:** 23 --- ## [Do I \*need\* a vacuum breaker in my shower hose?](https://boards.straightdope.com/t/do-i-need-a-vacuum-breaker-in-my-shower-hose/1025566)
**Author:** [@carlb](https://boards.straightdope.com/u/carlb)\ **Replies:** 7\ **Last updated:** [December 9, 2025, 9:01pm UTC](https://boards.straightdope.com/t/do-i-need-a-vacuum-breaker-in-my-shower-hose/1025566 "2025-12-09T21:01:32Z")
I replaced the hand-held shower head and its hose in our bathroom the other day. There was a part between the female end of the shower hose and the male fitting projecting from the wall. I removed it, installed the new s… --- ## [Is there a name for this number sequence?](https://boards.straightdope.com/t/is-there-a-name-for-this-number-sequence/1025537)
**Author:** [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Replies:** 9\ **Last updated:** [December 9, 2025, 7:44pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-this-number-sequence/1025537 "2025-12-09T19:44:35Z")
Where every entry is repeated the number of times it states? 1 22 333 4444 55555 666666 7777777 88888888… --- ## [How to model the length of the average unbroken maternal/paternal line of descent?](https://boards.straightdope.com/t/how-to-model-the-length-of-the-average-unbroken-maternal-paternal-line-of-descent/1025495)
**Author:** [@brossa](https://boards.straightdope.com/u/brossa)\ **Replies:** 13\ **Last updated:** [December 9, 2025, 1:49pm UTC](https://boards.straightdope.com/t/how-to-model-the-length-of-the-average-unbroken-maternal-paternal-line-of-descent/1025495 "2025-12-09T13:49:25Z")
I’m trying to figure out how many generations we would ‘expect’ a matrilineal or patrilineal line to persist, given n children each generation. So if a given person has n offspring, and each of the same-sex offspring ha… --- ## [Insulating a hollow steel door.](https://boards.straightdope.com/t/insulating-a-hollow-steel-door/485208)
**Author:** [@Baal\_Houtham](https://boards.straightdope.com/u/Baal_Houtham)\ **Replies:** 30\ **Last updated:** [December 8, 2025, 7:50pm UTC](https://boards.straightdope.com/t/insulating-a-hollow-steel-door/485208 "2025-12-08T19:50:50Z")
My front door is steel with a 2’x3’ double pane window. The door feels so cold on frigid days that I’ve always assumed it’s uninsulated. Occasionally I consider taking the door off its hinges, drilling several holes in t… --- ## [Color theory vs. light theory](https://boards.straightdope.com/t/color-theory-vs-light-theory/1025474)
**Author:** [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Replies:** 13\ **Last updated:** [December 8, 2025, 4:20pm UTC](https://boards.straightdope.com/t/color-theory-vs-light-theory/1025474 "2025-12-08T16:20:45Z")
I got into a discussion with an art teacher, and we’re kind of stuck at the point about brown being clearly visible to humans, but not being in the rainbow. I know why black and white aren’t colors, but what do we say fo… --- ## [How long would it take for a modern city to disintegrate...](https://boards.straightdope.com/t/how-long-would-it-take-for-a-modern-city-to-disintegrate/548887)
**Author:** [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Replies:** 68\ **Last updated:** [December 8, 2025, 9:35am UTC](https://boards.straightdope.com/t/how-long-would-it-take-for-a-modern-city-to-disintegrate/548887 "2025-12-08T09:35:58Z")
without proper maintenance? Suppose, through some biological disaster, humanity is basically reduced to a population of a couple hundred thousand naked monkeys strolling about the globe. At that point it’s unlikely any… --- ## [If Pete Hegseth is guilty of a war crime punishable by the ICC ... so what?](https://boards.straightdope.com/t/if-pete-hegseth-is-guilty-of-a-war-crime-punishable-by-the-icc-so-what/1025368)
**Author:** [@HeyHomie](https://boards.straightdope.com/u/HeyHomie)\ **Replies:** 81\ **Last updated:** [December 8, 2025, 1:36am UTC](https://boards.straightdope.com/t/if-pete-hegseth-is-guilty-of-a-war-crime-punishable-by-the-icc-so-what/1025368 "2025-12-08T01:36:06Z")
I’ve read here and there, mostly via memes, that it’s not unlikely that the ICC will want a word with Pete Hesgeth regarding possible war crimes as relates to the strikes on Venezuelan “drug” boats. The thing is, I’m pre… --- ## [How to specify bifocal glasses?](https://boards.straightdope.com/t/how-to-specify-bifocal-glasses/1025300)
**Author:** [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Replies:** 32\ **Last updated:** [December 7, 2025, 11:22pm UTC](https://boards.straightdope.com/t/how-to-specify-bifocal-glasses/1025300 "2025-12-07T23:22:03Z")
In my family (parents and 5 siblings) I’m the only one that never needed glasses. But for some time (I’m 79) I do use over the counter reading glasses for close work. I use +1.75 for using the computer and I just went u… --- ## [If my green ground wire is carrying current, how would I know?](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346)
**Author:** [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Replies:** 33\ **Last updated:** [December 7, 2025, 2:18am UTC](https://boards.straightdope.com/t/if-my-green-ground-wire-is-carrying-current-how-would-i-know/1025346 "2025-12-07T02:18:15Z")
I understand that the green wire attaches to a bare ground wire and provides a path to ground in case the hot wire touches something that it’s not supposed to. But doesn’t this just complete the circuit? Assuming that a… --- ## [Submarine pressure hull](https://boards.straightdope.com/t/submarine-pressure-hull/799048)
**Author:** [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Replies:** 23\ **Last updated:** [December 7, 2025, 12:29am UTC](https://boards.straightdope.com/t/submarine-pressure-hull/799048 "2025-12-07T00:29:58Z")
I’m reading about the USS Nautilus. For traveling under the ice, reverse fathomometers were installed during a refit. Are there covered openings in the pressure hull for installing new equipment, or are they cut as neede… --- ## [How sensitive to disruption / efficient are modern airliner wings?](https://boards.straightdope.com/t/how-sensitive-to-disruption-efficient-are-modern-airliner-wings/1025398)
**Author:** [@DETXL](https://boards.straightdope.com/u/DETXL)\ **Replies:** 6\ **Last updated:** [December 5, 2025, 10:10pm UTC](https://boards.straightdope.com/t/how-sensitive-to-disruption-efficient-are-modern-airliner-wings/1025398 "2025-12-05T22:10:49Z")
I had a pre-dawn flight on an Airbus today, and found staring at the top of the wing, and the hoist points you can see here: https://upload.wikimedia.org/wikipedia/commons/thumb/8/85/Airbus\_A319\_left\_wing\_during\_the\_land… --- ## [Laser Range Finder?](https://boards.straightdope.com/t/laser-range-finder/1025382)
**Author:** [@19USMC69](https://boards.straightdope.com/u/19USMC69)\ **Replies:** 24\ **Last updated:** [December 5, 2025, 8:16pm UTC](https://boards.straightdope.com/t/laser-range-finder/1025382 "2025-12-05T20:16:51Z")
I’ve seen these used by golfers and at shooting ranges. The terminal end of the laser is always a hard object. I want to measure the distance from the deck of a ship to the water. Obviously there’s a difference between … --- ## [Black coffee and dark chocolate](https://boards.straightdope.com/t/black-coffee-and-dark-chocolate/1025053)
**Author:** [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Replies:** 77\ **Last updated:** [December 5, 2025, 8:04pm UTC](https://boards.straightdope.com/t/black-coffee-and-dark-chocolate/1025053 "2025-12-05T20:04:39Z")
Word is that black coffee and dark chocolate are good for your health while milk chocolate and coffee with cream lack those benefits. So here I am eating dark chocolate and drinking black coffee. What if next I drink a … --- ## [Stupid Facebook question: Commenting with an animated .gif](https://boards.straightdope.com/t/stupid-facebook-question-commenting-with-an-animated-gif/1025406)
**Author:** [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Replies:** 8\ **Last updated:** [December 5, 2025, 9:03am UTC](https://boards.straightdope.com/t/stupid-facebook-question-commenting-with-an-animated-gif/1025406 "2025-12-05T09:03:47Z")
I know this is a dumb question, but how do I put an animated .gif into a comment, that is not one of the ones you can choose from the small library with the .gif button? I tried to post this in a comment: Since the a… --- ## [ChatGPT level of confidence](https://boards.straightdope.com/t/chatgpt-level-of-confidence/1017717)
**Author:** [@Sitnam](https://boards.straightdope.com/u/Sitnam)\ **Replies:** 140\ **Last updated:** [December 4, 2025, 5:37pm UTC](https://boards.straightdope.com/t/chatgpt-level-of-confidence/1017717 "2025-12-04T17:37:10Z")
I wouldn’t cite Wikipedia for a Thesis but it’s good enough to win a bar argument. It’s not perfect, I don’t believe everything on it I read, but I am willing to accept it’s mostly true. There is a level of confidence … --- ## [Will the city of Teheran be abandoned next week, due to drought?](https://boards.straightdope.com/t/will-the-city-of-teheran-be-abandoned-next-week-due-to-drought/1022757)
**Author:** [@chappachula](https://boards.straightdope.com/u/chappachula)\ **Replies:** 61\ **Last updated:** [December 4, 2025, 10:02am UTC](https://boards.straightdope.com/t/will-the-city-of-teheran-be-abandoned-next-week-due-to-drought/1022757 "2025-12-04T10:02:40Z")
A few weeks ago, I noticed a couple of astounding headlines. Iran is in critical trouble with water supplies, and its capital city may have to be abandoned within weeks. Since then, I haven’t seen any serious talk abou… --- ## [Drug cartels and payment](https://boards.straightdope.com/t/drug-cartels-and-payment/1025343)
**Author:** [@Cachalot](https://boards.straightdope.com/u/Cachalot)\ **Replies:** 7\ **Last updated:** [December 4, 2025, 4:05am UTC](https://boards.straightdope.com/t/drug-cartels-and-payment/1025343 "2025-12-04T04:05:03Z")
I just watched The Mule starring Clint Eastwood as an elderly man who becomes a courier for a drug cartel. According to what we see in the movie, he was paid very well. A shot of him looking at his pay packet after one r… --- ## [Do injured Guardsmen go to a base Hospital?](https://boards.straightdope.com/t/do-injured-guardsmen-go-to-a-base-hospital/1025310)
**Author:** [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Replies:** 10\ **Last updated:** [December 3, 2025, 1:54pm UTC](https://boards.straightdope.com/t/do-injured-guardsmen-go-to-a-base-hospital/1025310 "2025-12-03T13:54:20Z")
ABC reports the guardsmen shot in DC gave a thumbs up to questions. It was reported he is stable condition in a local hospital under heavy guard I thought all active military servicemen use a base hospital? Does that in… --- ## [What time period are the fairy tales set in?](https://boards.straightdope.com/t/what-time-period-are-the-fairy-tales-set-in/618113)
**Author:** [@SDMBKL](https://boards.straightdope.com/u/SDMBKL)\ **Replies:** 59\ **Last updated:** [December 2, 2025, 11:36pm UTC](https://boards.straightdope.com/t/what-time-period-are-the-fairy-tales-set-in/618113 "2025-12-02T23:36:39Z")
It appears that some fairy tales set in the Middle Ages or the Renaissance in contemporary picture book illustrations. Princesses would commonly wear the tall pointy hat called a hennin, and men wear these short and long… --- ## [How did folk "on the American frontier" view travelers/home security?](https://boards.straightdope.com/t/how-did-folk-on-the-american-frontier-view-travelers-home-security/1025148)
**Author:** [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)\ **Replies:** 50\ **Last updated:** [December 2, 2025, 10:57pm UTC](https://boards.straightdope.com/t/how-did-folk-on-the-american-frontier-view-travelers-home-security/1025148 "2025-12-02T22:57:39Z")
My initial thought is the western frontier - from either the Little House books or westerns. But I suppose this could apply to folk crossing the Cumberland Gap in the late 1700s, or any other period of expansion. I’m t… --- ## [US Post Offices "RUR. STA."](https://boards.straightdope.com/t/us-post-offices-rur-sta/1025287)
**Author:** [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Replies:** 15\ **Last updated:** [December 2, 2025, 10:37pm UTC](https://boards.straightdope.com/t/us-post-offices-rur-sta/1025287 "2025-12-02T22:37:51Z")
Am doing some research on small US towns and their post offices. In the process it’s not unusual to see post office names of the format: Marmarth Rur. Sta. (1974-Date) (in Slope County ND) Which follows chronologicall… --- ## [How does not being able to sue the post office square with the first amendment?](https://boards.straightdope.com/t/how-does-not-being-able-to-sue-the-post-office-square-with-the-first-amendment/1025154)
**Author:** [@Sigene](https://boards.straightdope.com/u/Sigene)\ **Replies:** 13\ **Last updated:** [December 2, 2025, 8:20pm UTC](https://boards.straightdope.com/t/how-does-not-being-able-to-sue-the-post-office-square-with-the-first-amendment/1025154 "2025-12-02T20:20:44Z")
This case of a person wanting to sue the post office Apparently a law has the Postal Service exempt from such lawsuits. However, the first amendment guarantees the right to petition the government for redress of grie… --- ## [What are "silver fish" in the context of animal feed?](https://boards.straightdope.com/t/what-are-silver-fish-in-the-context-of-animal-feed/1025322)
**Author:** [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Replies:** 3\ **Last updated:** [December 2, 2025, 12:16pm UTC](https://boards.straightdope.com/t/what-are-silver-fish-in-the-context-of-animal-feed/1025322 "2025-12-02T12:16:10Z")
Triggered by the mention of eating insect protien in a thread, I was reminded of the attempt to popularize farming black soldier fly larva for human consumption. Googling around on that and quickly skimming articles, I w… --- ## [Can ANY ship/boat be "flagged" in any country a person/company chooses?](https://boards.straightdope.com/t/can-any-ship-boat-be-flagged-in-any-country-a-person-company-chooses/1025067)
**Author:** [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Replies:** 33\ **Last updated:** [December 2, 2025, 5:00am UTC](https://boards.straightdope.com/t/can-any-ship-boat-be-flagged-in-any-country-a-person-company-chooses/1025067 "2025-12-02T05:00:08Z")
I know with ships that do international travel they usually register/flag the ship in some few countries that are very forgiving in their laws to their owners. But what if I have a cargo vessel plying the Great Lakes? … --- ## [Is there a way to save the picture on my windows Lock Screen?](https://boards.straightdope.com/t/is-there-a-way-to-save-the-picture-on-my-windows-lock-screen/1025308)
**Author:** [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Replies:** 6\ **Last updated:** [December 1, 2025, 11:33pm UTC](https://boards.straightdope.com/t/is-there-a-way-to-save-the-picture-on-my-windows-lock-screen/1025308 "2025-12-01T23:33:41Z")
I’ve tried right clicking and left clicking but no response. --- ## [Language: If whales had it, would we know?](https://boards.straightdope.com/t/language-if-whales-had-it-would-we-know/62392)
**Author:** [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Replies:** 192\ **Last updated:** [December 1, 2025, 10:41pm UTC](https://boards.straightdope.com/t/language-if-whales-had-it-would-we-know/62392 "2025-12-01T22:41:07Z")
If whales sang love sonnets or expositions on philosophy and mathematics to one another, would we know about it? I suppose that this is a signal processing problem: given what we know about whales’ listening and vocaliza… --- ## [About fuel consumption on a private aircraft (better explained in OP)](https://boards.straightdope.com/t/about-fuel-consumption-on-a-private-aircraft-better-explained-in-op/1025268)
**Author:** [@HeyHomie](https://boards.straightdope.com/u/HeyHomie)\ **Replies:** 10\ **Last updated:** [December 1, 2025, 5:45pm UTC](https://boards.straightdope.com/t/about-fuel-consumption-on-a-private-aircraft-better-explained-in-op/1025268 "2025-12-01T17:45:04Z")
Let’s say I’m flying my Cessna 182 from Kansas City to Miami. The distance is 1300 nm. The aircraft’s range is 1000 nm. So is it better to fill up in Kansas City, fly a hair less than 1000 nm, then buy fuel for the remai… --- ## [Do all English mayors wear this golden necklace-looking thing?](https://boards.straightdope.com/t/do-all-english-mayors-wear-this-golden-necklace-looking-thing/1025210)
**Author:** [@HeyHomie](https://boards.straightdope.com/u/HeyHomie)\ **Replies:** 28\ **Last updated:** [December 1, 2025, 3:50pm UTC](https://boards.straightdope.com/t/do-all-english-mayors-wear-this-golden-necklace-looking-thing/1025210 "2025-12-01T15:50:09Z")
See how this guy is wearing a … well, I don’t know what, exactly. It’s sort of like a necklace but way bigger. English mayors of cities large and small are depicted wearing them while they are doing their duties. What i… --- ## [Replacement vacuum bags for a Ferrex F-WDV6.2](https://boards.straightdope.com/t/replacement-vacuum-bags-for-a-ferrex-f-wdv6-2/1025236)
**Author:** [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Replies:** 9\ **Last updated:** [December 1, 2025, 3:21pm UTC](https://boards.straightdope.com/t/replacement-vacuum-bags-for-a-ferrex-f-wdv6-2/1025236 "2025-12-01T15:21:22Z")
I just bought a vacuum cleaner at Aldis, &a Ferrex F-WDV6.2, and it seems to be very good. But for the life of me, I cannot find any vacuum bags. Aldi’s does list any there IS NO Ferrex help line, and Aldi’s customer … --- ## [What is the median shape of the surface of the Earth](https://boards.straightdope.com/t/what-is-the-median-shape-of-the-surface-of-the-earth/1025263)
**Author:** [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Replies:** 4\ **Last updated:** [December 1, 2025, 2:09pm UTC](https://boards.straightdope.com/t/what-is-the-median-shape-of-the-surface-of-the-earth/1025263 "2025-12-01T14:09:52Z")
I have been obtaining amusement from perusing (not entirely passively) some discussions amongst Flat Earth Conspiracy Theorists and rational persons, and a question occurred to me. According to General Relativity, the E… [Previous page](https://boards.straightdope.com/c/factual-questions/9.md?page=21) [Next page](https://boards.straightdope.com/c/factual-questions/9.md?page=23)