Welcome to the science section
of the Wikipedia reference desk.

Select a section:

WP:RD/S

Want a faster answer?

Main page: Help searching Wikipedia

How can I get my question answered?

Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
Post your question to only one section, providing a short header that gives the topic of your question.
Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
Don't post personal contact information – it will be removed. Any answers will be provided here.
Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
Note:
- We don't answer (and may remove) questions that require medical diagnosis or legal advice.
- We don't answer requests for opinions, predictions or debate.
- We don't do your homework for you, though we'll help you past the stuck point.
- We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

March 31

Surviving a poisoning attempt

Can any opioid antagonists be taken by mouth with, or dissolved in, an alcoholic drink? (Not medical advice -- this question was inspired by a cut scene in Criminal Cases (what, no article for such a popular video game?!) where Chief Ripley takes an opioid antagonist with champagne to survive an assassination attempt with a poisoned dart!) 2601:646:9882:46E0:ACB0:15FA:37FF:553C (talk) 03:12, 31 March 2023 (UTC)[reply]

Maybe Criminal Case (video game)? As to the question, no idea. --174.89.12.187 (talk) 04:02, 31 March 2023 (UTC)[reply]

While they may not dissolve in alcohol or water (alcoholic drinks are mostly water), they could certainly be ingested with them in powdered form. I wonder more if it is practically possible to deliver an opioid overdose using a dart. --Lambiam 09:08, 31 March 2023 (UTC)[reply]

Given that tranquilizer darts for large animals often include a "super-opioid" like etorphine, which is waaaay more potent than fentanyl (see table) and standard procedure for using them is for the personnel to have a primed syringe of naloxone ready to go in case of accidents, I'd say signs point to yes. --47.155.46.15 (talk) 06:55, 2 April 2023 (UTC)[reply]

He'd have been far better off with an injection of the antagonist. And would still need care as extra doses are often required as they just temporarily stop the effects so one has to wait for the opiods to leave the system. NadVolum (talk) 10:53, 31 March 2023 (UTC)[reply]

Well, first of all it's a she, and apparently she chose ingestion with champagne instead of an injection in order for it to be inconspicuous (given that her objective was not only to survive, but also to fake her own death in order to fool the bad guys). As far as the extra doses, that would not be a problem in this case -- the second dose would be administered by the local EMS (in this case, the Corps of Firefighters of Catalonia), and any subsequent doses at the hospital. And yes, ingestion of powdered antidote in champagne should work in theory even if it doesn't dissolve (in that case, champagne would be uniquely suitable because the bubbles would act to keep the antidote particles suspended in the liquid and thereby help ensure that she takes the full dose) -- what I was concerned about is the possibility that the alcohol might interfere with the antidote and make it less effective, would that be likely? 2601:646:9882:46E0:D025:DD3C:502E:4122 (talk) 02:26, 3 April 2023 (UTC)[reply]

Hypnotism of psychiatrist

Many movies show psychiatrist hypnotising patients to bring out deep, hidden secrets.

Is it real? Is it reliable as many says Homeopathy is not good for treatment?

All psychiatrists I met, ask questions and give medicines. Couencellers also do not hypnotise. Larrenduusser (talk) 07:45, 31 March 2023 (UTC)[reply]

Have you read Hypnosis? ←Baseball Bugs ^{What's up, Doc?} carrots→ 08:19, 31 March 2023 (UTC)[reply]

Quoting from the section Hypnosis § Hypnotherapy: "Hypnotherapy was historically used in psychiatric and legal settings to enhance the recall of repressed or degraded memories, but this application of the technique has declined as scientific evidence accumulated that hypnotherapy can increase confidence in false memories.^[95]" This suggests it is still being done by some practitioners, but that it is not a good idea. For more, see Age regression in therapy. --Lambiam 08:43, 31 March 2023 (UTC)[reply]

I don't see what hypnosis has to do with homeopathy, but both are real things. Shantavira|^{feed me} 08:44, 31 March 2023 (UTC)[reply]

Did you mean hypnotherapy? Homeopathy is total nonsense. NadVolum (talk) 10:44, 31 March 2023 (UTC)[reply]

Because this is a general English resource, I want to point out that in India, the word "homeopathy" is often incorrectly used to refer to "treating the whole body." So, when they hear that homepathy is garbage, they argue that it isn't, mainly because they are referring to something else. 97.82.165.112 (talk) 10:59, 31 March 2023 (UTC)[reply]

I just had a look at the article and it describes India as supporting the total quackery version rather than something different. Have you got something showing the alternative meaning? NadVolum (talk) 11:08, 31 March 2023 (UTC)[reply]

Other than moving from Bangalore to the United States seven years ago after living there since 1973, no. 97.82.165.112 (talk) 13:44, 31 March 2023 (UTC)[reply]

It would be better if someone wth experience of the place looked into it and got a citation as I can see it being easy to misunderstand the situation. I think I'll just have to go with the article for the moment thanks. NadVolum (talk) 14:13, 31 March 2023 (UTC)[reply]

Is it real and efficacious? Nobody knows for sure, with most mainstream scientists defaulting to the nondeceptive placebo explanation, which makes sense to me. It’s also difficult to measure and replicate because each individual has a different level of suggestibility. Hypnotherapy in movies is more of a theatrical device for narrative. The most famous example is of an answering machine. Nobody has answering machines anymore, but they work great in film and television to further the story. In other words, this works great in fiction, not so much in real life. Viriditas (talk) 22:02, 2 April 2023 (UTC)[reply]

Work–Energy principle.

Who was the first to establish it? Our article Gaspard-Gustave de Coriolis states that happened in his period (i.e. around 1829). It also indicates that this principle derives from Newton's second law. Yet, the article does not mention any certain person who was the first to engross the principle. 2A06:C701:746E:2200:952B:99D5:60D:342 (talk) 14:43, 31 March 2023 (UTC)[reply]

As far as I remember, the principle (along with the very concepts of mechanical work and of kinetic energy) was established by

Gottfried Wilhelm von Leibniz. Эйхер (talk) 14:52, 31 March 2023 (UTC)[reply]

Leibniz indicated the importance of the product of mass multiplied by velocity squared, but he did not mention the concept of work. Our article Gaspard-Gustave de Coriolis states that principle was established in de Coriolis's period (i.e. around 1829). 2A06:C701:746E:2200:952B:99D5:60D:342 (talk) 15:27, 31 March 2023 (UTC)[reply]

I would say the person who really established energy as a quantity was James Prescott Joule. NadVolum (talk) 14:53, 31 March 2023 (UTC)[reply]

But I'm not asking about the energy as a quantity, but rather about discovering the equation "work = difference between kinetic energies". 2A06:C701:746E:2200:952B:99D5:60D:342 (talk) 15:34, 31 March 2023 (UTC)[reply]

It's not one person. The faulty Great man theory of scientific development is too concerned with crediting the great discoveries of science as solely the responsibility of a few scientific superheroes, where in reality these sorts of things are built up over time by the contributions of hundreds of people, some well known, and some obscure. According to Work (physics), the concept of work has alternately been ascribed to de Coriolis as above, as well as Salomon de Caus in his work Les Raisons des forces mouvantes (the reasons for motive forces). Some also consider John Smeaton to have contributed to the concept. Regarding energy, wikipedia has a whole article titled History of energy, which names a whole plethora of people who contributed to developing the concept, though it credits Thomas Young (scientist) specifically with naming it "energy". Of special note is the often not credited Émilie du Châtelet, who contributed as much as anyone to the modern notions of conservation of energy (though the term hadn't been invented yet), and the development of the idea of energy as a distinct quantity from momentum. Several sites do credit Joule (named above) with the first practical tests of the work-energy theorem, see [1] and [2] for example. But most also recognize that Joule didn't invent the concept, he just came up with the experiments to test it.--Jayron 32 15:27, 31 March 2023 (UTC)[reply]

I'm asking about the equation "work = difference between kinetic energies". Did any of the persons you have mentioned indicate this equation? 2A06:C701:746E:2200:952B:99D5:60D:342 (talk) 15:31, 31 March 2023 (UTC)[reply]

According to this, "Although we don’t know who to attribute the Theorem to specifically, we do know it’s based on the previous work of Gaspard Gustave de Coriolis and James Prescott Joule, whose work in turn built upon that of Isaac Newton’s Second Law of Motion." This book credits Joule specifically, but only in passing, and I can't find any confirmation of that. I think the "we don’t know who to attribute the Theorem to specifically" is the best answer, though Joule and Coriolis, among others, had contributions to it. --Jayron 32 15:59, 31 March 2023 (UTC)[reply]

thanks. 2A06:C701:4264:CA00:4401:F4E2:2C50:A5C9 (talk) 02:56, 2 April 2023 (UTC)[reply]

The issue was (I think) not so much establishing the equation, but developing the notions of "work" and "kinetic energy" as physical quantities definable by formulas. Once you have these defined, it takes only a few elementary calculus steps to derive the relationship. --Lambiam 19:26, 3 April 2023 (UTC)[reply]

Are there any applications for rust?

thanks Rich (talk) 18:03, 31 March 2023 (UTC)[reply]

Thermite. --Jayron 32 18:05, 31 March 2023 (UTC)[reply]

...and it can be recycled back to iron as it is hydrated hematite, mostly. Mike Turnbull (talk) 18:49, 31 March 2023 (UTC)[reply]

Some iron objects or structures deliberately have rust for appearance (see Weathering steel), and some kind of rust may actually protect from further corrosion. Yellow ochre is a natural form used for pigments. And it has use as a medium[3][4] or for symbolism in visual arts as a sign of neglect or gradual decay of society. Graeme Bartlett (talk) 21:48, 31 March 2023 (UTC)[reply]

Do you mean are there things which can be applied to treat or prevent rust, or do you mean are there things for which rust can be used? DuncanHill (talk) 22:17, 31 March 2023 (UTC)[reply]

the second thing, actual use of rust(iron rust).136.36.123.146 (talk) 05:37, 1 April 2023 (UTC)[reply]

Apparently enough people do not only want iron surfaces to rust, but to do so quickly and with consistent results of a high-quality uniform rust, for there to be a market for a rust accelerator.^[5] My guess is that the purpose is to produce a patina of a certain esthetic quality. --Lambiam 10:04, 1 April 2023 (UTC)[reply]

I recall a college campus building from the 1970s that was built with an exterior that quickly developed what its designers called "an attractive oxide coating". The students called the building a "rust-bucket". ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:17, 1 April 2023 (UTC)[reply]

Disk drives/tapes? Martin of Sheffield (talk) 09:44, 1 April 2023 (UTC)[reply]

These are based on magnetite, which is a different iron oxide than the oxides plain rust is comprised of. --Lambiam 10:08, 1 April 2023 (UTC)[reply]

Though nevertheless the slang term "spinning rust" came into usage. Modern drives use cobalt alloys, which permit higher density of magnetic domains and thus storage capacity. --47.155.46.15 (talk) 07:18, 2 April 2023 (UTC)[reply]

It could in principle be used as a low-cost abrasive, but I don't know whether it is in fact used for this. 2601:646:9882:46E0:A5F2:1021:A63E:67E0 (talk) 01:16, 2 April 2023 (UTC)[reply]

What about, conceivably, "rustene" a 2-dimensional rust, analogous to graphene and silicene? Rich (talk) 10:05, 3 April 2023 (UTC)[reply]

I'm surprised nobody has mentioned jeweller's rouge. --jpgordon^{𝄢𝄆𝄐𝄇} 05:11, 4 April 2023 (UTC)[reply]

April 1

Element 717

What would be the abbreviation for the systematic name of a hypothetical element of atomic number 717? – MrPersonHumanGuy (talk) 10:07, 1 April 2023 (UTC)[reply]

@MrPersonHumanGuy The IUPAC recommendation shows that 717 = SeptUnSeptium [capitals added for clarity] and hence Sus. Not likely to have a real-world utility any time soon.... Mike Turnbull (talk) 10:39, 1 April 2023 (UTC)[reply]

Calculating pH of strong bases by molarity.

I don't believe you can use the pH = 14 - pOH to calculate the pH of strong bases if the pH would otherwise be over 14, right?

I believe the biggest molarity of NaOH and Ca(OH)2 is 4 M and .016 M, per molecular weight. If we used the above formula, and try to calculate the pH of 1 M NaOH and 4 M NaOH, we get:

[OH-] = 1 M

pH = 14 - pOH

pOH = -log[OH-] = -log[1] = 0

So pH = 14 - 0 = 14.

But if 4 M,

pOH = -log(4) = 0.60

pH = 14 - 0.60 = 13.40

Clearly a pH of 4 M base should be higher than 1 M strong base. So looks like the way to solve it is to use the 1.0 * 10^-7 formulas. But are there any other examples of formulas that can have flaws? 2601:249:8200:A640:6192:535F:DD86:406C (talk) 14:07, 1 April 2023 (UTC).[reply]

I think you made an arithmetic error here: -log(4) = -0.60, so the pH would be 14.60, not 13.40. 2601:646:9882:46E0:A5F2:1021:A63E:67E0 (talk) 02:17, 2 April 2023 (UTC)[reply]

Thanks, resolved. This was ironic as it was a ChatGPT error. A simple math error, which I later confronted it. I hope it doesn't make it again. 64.107.3.137 (talk) 00:23, 5 April 2023 (UTC).[reply]

Resolved

April 3

Slavery and colonial rule

Moved to Wikipedia:Reference desk/Humanities

April 4

Nutrient Reference Value

I just came across the acronym ‘NRV’ and found that none of the meanings given in that page fit. A little more research in the internet showed that it stands for ‘Nutrient Reference Value’ and that these values “are set for 13 vitamins and 14 minerals for the purposes of food labelling and are EU guidance levels on the daily amount of vitamin or mineral that the average healthy person needs to prevent deficiency.”[6]. This sounds pretty important, at least to me as a layperson. So I'm wondering why we have no article about the lemma. Is there a reason for that (maybe such as that it's better known under a synonymous name) or should we create one? (We could take the article Reference Daily Intake as a template.) ◅ Sebastian 16:59, 4 April 2023 (UTC)[reply]

The concept is due to the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU), a joint committee of the FAO and WHO.[7] For an overview and history, see here. For the latest NRVs determined by the CCNFSDU, see here. --Lambiam 17:28, 4 April 2023 (UTC)[reply]

Thanks, Lambiam. The values differ a bit from the list i found, but imho your source seems a bit more reliable. Only, what do you think the comma values such as “Iron 14 mg, 22 mg” mean? Possibly the values for ♂︎ and ♀︎, but i don't see a note to that effect, and i wasn't aware NRV made that distinction. ◅ Sebastian 19:08, 4 April 2023 (UTC)[reply]

The numbers reflect different absorption percentages, corresponding to different dietary patterns. This is described in 6.3.2: "NRVs-R with same value as NRV and additional information" of the overview and history paper, pp. 44–45:

Dietary descriptions

15% absorption Diversified diets, rich in meat, fish, poultry and/or rich in fruit and vegetables

10% absorption Diets rich in cereals, roots or tubers, with some meat, fish, poultry and/or containing some fruit and vegetables

Conclusion

CCNFSDU (2015) agreed to establish two NRVs-R for iron of 14 mg (15 percent absorption) and 22 mg (10 percent absorption), revised from a single NRV of 14 mg.

--Lambiam 19:41, 4 April 2023 (UTC)[reply]

Thanks, Lambiam, makes sense. ◅ Sebastian 10:01, 6 April 2023 (UTC)[reply]

So, any answer to my original question? Is that already covered in Wikipedia somewhere or should we create an article? ◅ Sebastian 10:01, 6 April 2023 (UTC)[reply]

It does not seem to be covered. A possible approach is to incorporate the material, together with that of Dietary Reference Intake and Reference Daily Intake, in the article Dietary Reference Value, which ought to become an umbrella article presenting a global and historic overview of the concepts involved. --Lambiam 15:46, 6 April 2023 (UTC)[reply]

April 5

Space X Rocket Fuel

Could someone please tell me how Space-X produces their rocket fuel? I assume the liquid oxygen is produced by electrolysis, is it possible to do this using solar power? and how is the methane produced? Thanks 49.177.70.210 (talk) 07:40, 5 April 2023 (UTC)[reply]

See liquid rocket propellant, liquid oxygen, and methane for production methods. I doubt very much they would produce their own fuel. Why not just buy it on the open market? I suppose it would be possible using solar power but that would be a painfully slow process. Shantavira|^{feed me} 08:26, 5 April 2023 (UTC)[reply]

There are several ways to produce oxygen, but for high purity in industrial quantity, it's done by distillation of air. Methane is produced by distillation of natural gas. The pumps to run the distillation process require electricity, which could come from renewable sources. For some other common rocket fuels: RP-1 (a kind of kerosene) is distilled from crude oil, LH2 (liquid hydrogen) is normally produced by a reaction of steam with methane. Hypergolics and solids require some more complex chemistry. All these fuels are produced in bulk by chemical companies. Buying those fuels off the shelf is much cheaper for the space companies than producing it themselves.

SpaceX likes talking about making rocket fuel on Mars. There, they would use a reaction of carbon dioxide with water to produce both methane and oxygen. But that's just talk; they aren't anywhere close to a return mission to Mars. Crewed Mars mission have been twenty years into the future for decades. PiusImpavidus (talk) 09:30, 5 April 2023 (UTC)[reply]

Industrial quantities of liquid oxygen are generally produced by fractional distillation of air; see air separation.

And yes, SpaceX seems to source their liquid oxygen on the open market rather than making their own. There was some substantial coverage in 2021 raising concerns about potential shortages, because so much liquid oxygen was being consumed for medical purposes. TenOfAllTrades(talk) 12:24, 5 April 2023 (UTC)[reply]

Anything that can be done using electricity can be done with electricity produced from solar power. The economics are a different matter. WP:WHAAOE: Power-to-gas includes power-to-H2 and power-to-methane. -- 47.155.46.15 (talk) 06:24, 6 April 2023 (UTC)[reply]

Can I buy reverse invisible pens?

Not invisible molecules that become visible with UV or heat but visible molecules that become invisible with one of those things (perhaps breaking up to pieces that like to evaporate?). For semi-permanently marking expensive paper i.e. an atlas still being able to unmark and reuse up to preferably 10+ cycles before the process would naked eye affect it much. For example a pen with ink at least 10² or 10³ times less UV-resistant than any common poster ink or book paper. Sagittarian Milky Way (talk) 20:12, 5 April 2023 (UTC)[reply]

Nautical charts are quite expensive and are regularly marked up in 2B pencil and then erased. Is this the sort of thing you were meaning? Martin of Sheffield (talk) 20:59, 5 April 2023 (UTC)[reply]

I remember most of the original blue ink for ocean coming off an eraser-sized strip of childhood book before the ballpoint ink did (though a 2B or HB pencil wouldn't have needed as much rubbing). How do I tell in advance about how many times a particular book or map can be erased before it looks bad? Sagittarian Milky Way (talk) 21:47, 5 April 2023 (UTC)[reply]

I would try using a fixative spray before marking with pencil. 136.56.52.157 (talk) 21:56, 5 April 2023 (UTC)[reply]

Don't use HB (a "normal" pencil) or you will leave a permanent impression. FYI, it is not uncommon for skippers to ban anything other than 2B being anywhere near the chart table (and that especially includes biros). It only takes someone plotting a fix in a hurry, or at night, or in bad weather with the wrong implement to ruin a chart. Martin of Sheffield (talk) 22:26, 5 April 2023 (UTC)[reply]

See Erasermate. 2601:646:9882:46E0:3053:CD03:BA5:3522 (talk) 07:05, 6 April 2023 (UTC)[reply]

2B or not 2B, there's no question. Go away, ye swab. Clarityfiend (talk) 08:08, 6 April 2023 (UTC) [reply]

:-) Martin of Sheffield (talk) 09:18, 6 April 2023 (UTC) [reply]

Or see ""Hey Ray: Erasable pens and reappearing images". www.cbsnews.com." and there is also FriXion brand pens, or look up "heat erase pen". Graeme Bartlett (talk) 07:09, 6 April 2023 (UTC)[reply]

Are you asking about disappearing ink? --Jayron 32 10:49, 6 April 2023 (UTC)[reply]

The lye one obviously wouldn't work cause even if repeatedly getting your paper above 10.5 pH just to see your notes doesn't permanently wrinkle the paper or something you couldn't erase one set of marks and write another. Lightly marking with the darker than usual 2B pencil seems safer. Sagittarian Milky Way (talk) 13:45, 6 April 2023 (UTC)[reply]

April 6

What's wrong with the “uno”?

Uno (unit) redirects to Parts-per notation#Uno (proposed dimensionless unit), a short paragraph, which cites that “the response to the proposal of the uno "had been almost entirely negative"”. What were the reasons against it? ◅ Sebastian 10:16, 6 April 2023 (UTC)[reply]

Have you read Reference 14 from that page? --Jayron 32 10:48, 6 April 2023 (UTC)[reply]

Unfortunately, the reference doesn't add anything to the quoted statement. Apparently, those responses (i.e. opinions solicited from peers) have not been published and were not discussed in detail. --Wrongfilter (talk) 10:58, 6 April 2023 (UTC)[reply]

Thanks, Wrongfilter. Your first sentence is exactly what i should have replied. But the second sentence goes a bit too far for me. Are we sure that they are not publicly available anywhere? I couldn't find any with a quick internet search, but that's not enough to rule it out. ◅ Sebastian 12:54, 6 April 2023 (UTC)[reply]

Searching a bit further, i found this from the IUPAC Interdivisional Committee on Nomenclature and Symbols (IDCNS):“Recommendation U3: […] [T]the use of the unit <U or uno> in combination with a prefix is to be preferred [over expressions such as ppm, ppb, and ppt].”[8] There are no considerations against this recommendation. ◅ Sebastian 13:48, 6 April 2023 (UTC)[reply]

See, however, Section 4.10 of the Report of the 15th meeting (17–18 April 2003) to the International Committee for Weights and Measures: "Dr Taylor suggested that the uno could be introduced as a special device for use with prefixes only so that, for example, the usage ppm could become μU, but the uno would not be a unit. This met with some objections and it was pointed out that such a change would require the approval of the General Conference."^[9] --Lambiam 19:48, 6 April 2023 (UTC)[reply]

In the old days, in math classes, we referred to 1 as the multiplication "Identity". ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:37, 7 April 2023 (UTC)[reply]

April 7

Harry the Lizard

I've asked a question about a lizard at the entertainment desk, here: Harry the Lizard.

I don't want to actually cross-post the question, but it occurred to me to add a link here because people who know about the biology of lizards might more likely be hanging around this reference desk. Suggest any replies go there rather than here too. AndyJones (talk) 13:06, 7 April 2023 (UTC)[reply]

Neuroscience and lack of inner monologues

Is there any neuroscience research on how people who report not having an inner monologue differ from those with?
Are there really differences in the brain? 2A02:908:424:9D60:714D:C368:7B6A:3F63 (talk) 17:35, 7 April 2023 (UTC)[reply]