Wikipedia:Reference desk/Archives/Science/2017 March 4

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March 4

NaK

Both sodium and potassium are solid at room temperature. If so, then why is NaK liquid at room temperature? 32ieww (talk) 00:02, 4 March 2017 (UTC)

Try looking at eutectic alloy for starters. It's quite common that a mixture of two or more components will have a lower melting point than either. Andy Dingley (talk) 00:13, 4 March 2017 (UTC)

Note that hydrogen and oxygen are both gases at temps and pressures where water (H₂O) is a liquid or solid. StuRat (talk) 00:22, 4 March 2017 (UTC)

It's disingenuous to use the example of water as an analogue for NaK which is a eutectic mixture not a distinct molecule. 204.28.125.102 (talk) 00:33, 4 March 2017 (UTC)

See Hanlon's razor to understand most of Stu's answers. He's not being disingenuous. I think he really believes he's useful. --Jayron32 00:55, 4 March 2017 (UTC)

The OP did not state that they were solely interested in states of matter for eutectic alloys and their constituent atoms. StuRat (talk) 01:09, 4 March 2017 (UTC)

Anyone can state true but unrelated facts all day. I could have said "George Washington was the first President of the United States" in response to the OP's question, and it would have been almost as relevant to answering it as your reply. --Jayron32 01:14, 4 March 2017 (UTC)

One way to think of it is that the different sized atoms makes it harder for the other atoms to crystallize into a solid by getting in the way or not being able to fit into the crystal. Freezing point depression is another similar phenomenon. Graeme Bartlett (talk) 05:13, 4 March 2017 (UTC)

For those wanting to know more about this substance, we have a NaK article. DMacks (talk) 10:48, 4 March 2017 (UTC)

I was going to make a joke about sodium, but Na, decided not to. Akld guy (talk) 23:08, 4 March 2017 (UTC)

'K. StuRat (talk) 23:27, 4 March 2017 (UTC)

He He, Ar Ar. Akld guy (talk) 23:59, 4 March 2017 (UTC)

I feel sad that all the good element jokes argon.32ieww (talk) 23:03, 7 March 2017 (UTC)

Did you hear that oxygen and magnesium are dating? OMg! --SuperJew (talk) 23:24, 7 March 2017 (UTC)

I heard their relationship went up in flames. StuRat (talk) 23:59, 7 March 2017 (UTC)

RFC of possible interest to contributors to this desk

See Talk:Chemistry#RFC on the inclusion of a particular passage in the lead of this article. Please contribute if you have an opinion. Thanks. --Jayron32 02:53, 4 March 2017 (UTC)

Should be fully neutralized and saturated now. --Kharon (talk) 11:35, 4 March 2017 (UTC)

If people are born gay why is one of the identical twins sometimes gay?

Apparently homosexuality is caused by a mixture of genetics, time in the uterus and environmental factors very early in the person's life? But those things would be virtually exactly the same for both twins right? — Preceding unsigned comment added by 2.102.185.215 (talk) 03:07, 4 March 2017 (UTC)

There is no consensus as to causes of homosexuality. The question as posed is unanswerable. Variability in humans on matters such as sexuality is such that there is no problem with believing that two identical twins could turn out to have different sexuality. --Jayron32 03:21, 4 March 2017 (UTC)

Genetically influenced traits that don't perfectly match the genotype is not uncommon - see penetrance. Further to what Jayron suggests, this could result from some unknown cause that actually differs between the twins, or it could also be caused by some stochastic process that leads to different outcomes even with arbitrarily similar conditions. Someguy1221 (talk) 03:41, 4 March 2017 (UTC)

(edit conflict) Quotes at Sexual orientation are apt here. "Currently, there is no scientific consensus about the specific factors that cause an individual to become heterosexual, homosexual, or bisexual – including possible biological, psychological, or social effects of the parents' sexual orientation." "No one knows what causes heterosexuality, homosexuality, or bisexuality.", "Although much research has examined the possible genetic, hormonal, developmental, social, and cultural influences on sexual orientation, no findings have emerged that permit scientists to conclude that sexual orientation – heterosexuality, homosexuality, or bisexuality – is determined by any particular factor or factors. The evaluation of amici is that, although some of this research may be promising in facilitating greater understanding of the development of sexual orientation, it does not permit a conclusion based in sound science at the present time as to the cause or causes of sexual orientation, whether homosexual, bisexual, or heterosexual." Those are direct opinions of scientific organizations on the matter. I'll leave it at that, as I have nothing more to add (not being a scientist who studies this, as the people who made those statements are.) --Jayron32 03:46, 4 March 2017 (UTC)

Note that genetics and environment may not be the only factors. There could also be a truly random factor. For example, your tendency towards freckles is genetic, and exposure to sunlight affects the total amount, but the location of each freckle can not be predicted by either. So, there appears to be a random factor at work there.

Another possibility is that the personality of the twins is such that they wanted to distinguish themselves from one another, so what ever one does, the other tries to do the opposite. StuRat (talk) 03:43, 4 March 2017 (UTC)

Ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha. So were they both gay to start with or both straight? Then you see what an absurd idea this is. Richard Avery (talk) 09:02, 4 March 2017 (UTC)

Not if those afforementioned personality traits result in the people gaining different environmental exposures resulting the final difference in sexuality. Ha ha ha ha ha... ----Seans Potato Business 10:42, 4 March 2017 (UTC)

Sexuality is rather flexible early on. It's only later that it becomes fixed. So, everyone is neither gay nor straight to begin with. They may have a genetic propensity towards one or the other, but that's not the whole story. StuRat (talk) 15:26, 4 March 2017 (UTC)

"Sexuality is rather flexible early on. It's only later that it becomes fixed" . You seem to have definitely answered a big question in developmental biology without telling anyone about it. Care to show your work? Fgf10 (talk) 17:59, 4 March 2017 (UTC)

Erikson's_stages_of_psychosocial_development#Fidelity:_identity_vs._role_confusion_.28adolescence.2C_13.E2.80.9319_years.29: "In later stages of adolescence, the child develops a sense of sexual identity.". StuRat (talk) 18:09, 4 March 2017 (UTC)

Psychoanalysis? Really? What are you going to use next for support? Homeopathy? Any actual evidence for your statement? Perhaps in a peer-reviewed scientific journal? Fgf10 (talk) 18:55, 4 March 2017 (UTC)

Erikson served as a professor at prominent institutions such as Harvard and Yale. A Review of General Psychology survey, published in 2002, ranked Erikson as the 12th most cited psychologist of the 20th century. But you accused me of making this up, and I've provided a source. If you disagree with the source, that's fine, but that doesn't mean I made it up. StuRat (talk) 19:12, 4 March 2017 (UTC)

No, it just means someone else made it up, someone who was acting without the benefit of modern neuroscience, and whose opinions should not be relied upon by anyone taking even the slightest interest in the actual scientific method. You have yet to provide any evidence for your statement. Fgf10 (talk) 19:21, 4 March 2017 (UTC)

You won't find any scientific evidence from neuroscience regarding definite proof of the causes and timing of sexual orientation. That science does not yet exist. The best we can, do, at present, is rely on theories proposed by experts in the field of psychology, and that's what I've provided. Would you have also disbelieved the Theory of Evolution at the time it was proposed, when there was no way to compare DNA of species ? StuRat (talk) 19:27, 4 March 2017 (UTC)

Well at least you agree your assertion was entirely baseless. Please don't make incorrect statements on the refdesk like they're facts. Fgf10 (talk) 20:56, 4 March 2017 (UTC)

I said no such thing. It's your assertion that neuroscience is the only basis for any facts which is entirely baseless. StuRat (talk) 21:39, 4 March 2017 (UTC)

Really? So sexuality isn't decided in the brain (through a currently unknown mechanism)? That's another bold claim that could use some evidence. Fgf10 (talk) 11:08, 5 March 2017 (UTC)

Again I made no such claim. You are in all out straw man mode. Sexuality is determined in the brain, via currently unknown mechanisms, and that's why we can't rely on neuroscience for evidence. Instead, we rely on observations by experts in the field, observing human behavior, which is exactly what I've provided. StuRat (talk) 15:41, 5 March 2017 (UTC)

As Someguy1221 has sorted hinted at, it's always very risky to say something is "virtually exactly the same". These studies discussion discordant monozygotic twins, many from birth or earlier, [1] [2] [3] [4] [5] [6] [7][8] [9]. I'm fairly sure the studies mentioned here [10] did include at least some monozygotic twins since Monochorionic twins only really occur when monozygotic. That study and others were also part of this review [11] and other studies which considered monochorionic twins, which implies it's also considering monozygotic twins although it doesn't seem to try and separate them. Note as clear from some of the later sources, the difference sometimes includes birth weight different enough to be considered discordant. Something mentioned there namely Twin-to-twin transfusion syndrome is a perhaps extreme example of a difference from before birth. Nil Einne (talk) 04:56, 4 March 2017 (UTC)

BTW one study which blew up in 2015 did find correlation between an epigenetic difference and sexual orientation with male identical twins [12] [13] [14] [15] [16] [17] [18]. As mentioned in thoses sources, such correlations could easily just be random noise particularly with such a small sample size. And the study was also AFAIK never published instead just presented at a conference, from the comments of the lead researcher I'm not sure if it will ever be published. I'm also fairly sure it didn't consider when these changes may have arose. But as illustrated in the earlier sources, some of which also considered epigenetic changes including IIRC in DNA methylation, these differences could arise in the womb or soon after birth. Nil Einne (talk) 05:19, 4 March 2017 (UTC)

I realise I probably should clarify my answer a bit. Some of the examples, e.g. TTTS is clearly leading to an environmental difference. Likewise epigenetic differences which could arise at some stage, may lead to phenotypic differences. In other cases phenotypic discordance at birth or in very early life may be discussed but there is limited idea of why. And even in the case of TTTS and epigenetic differences, you could go further back and consider why these arise. I'm not trying to suggest these all arise because of unknown differences, again as Someguy1221 said "it could also be caused by some stochastic process that leads to different outcomes". Also I'm using discordance generally as some sources use it, it seems discordant twins unqualified sometimes refers to twins with size differences at birth (normally as determined by birth weight). Nil Einne (talk) 10:40, 4 March 2017 (UTC)

From Identical twin: Monozygotic twins always have different phenotypes. ... Monozygotic twins, although genetically very similar, are not genetically exactly the same.

So-called identical twins are virtually indistinguishable physically, but often have very different behavioural or personality traits. One may be left-handed, the other right-handed. One may be extrovert, the other introvert. Different tastes in entertainment, sport, reading. One a nerd, the other dyslexic. Etc etc. -- Jack of Oz ^{[pleasantries]} 09:14, 4 March 2017 (UTC)

In the past many people denied that homosexuality is genetically determined. It seems now nobody doubts it. Let's there is a gene B on Y chromosome which is responsible for male sexuality. Many genes have mutations or polymorphisms and in the case of gene B the polymorphism A makes people homosexual. However, many polymorphisms have different penetrance, that is percentage of people with clearly defined phenotype. With two identical twins it is important to make sure they are really identical. There are mosaics. If they are truly identical then the one who is not homosexual is on the other side of penetrance. There are genes where any mutation has 100% penetrance, e.g. the ones that determine neurofibromatosis. --AboutFace 22 (talk) 22:41, 4 March 2017 (UTC)

"nobody doubts it" And what of people who are straight at first, but then become gay, or vice versa??? 2601:646:8E01:7E0B:348A:C4E6:44A4:A8FF (talk) 09:26, 7 March 2017 (UTC)

Stuka

How did the "Trumpet of Jericho" work? Was it a special purpose-made component attached to the airframe, or was it an integral part of some other component, such as the dive brakes? 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 07:53, 4 March 2017 (UTC)

It was a bolt-on gadget, usually fixed to the leading edge of the undercarriage leg. Here is one. I also found this larger type. A similar one can just be made out in this photo. Alansplodge (talk) 09:36, 4 March 2017 (UTC)

If anyone is curious, this was a siren attached to planes to intimidate the enemy: See Junkers_Ju_87#Ju_87B. StuRat (talk) 15:34, 4 March 2017 (UTC)

Can humans eat the algae that makes omega-3 fatty acids directly?

I've read in Fat Chance, by Dr Lustig, that wild caught fish is healthier than farmed fish because the fish eat algae that produces omega-3 fatty acids, though he admits that wild fish are more expensive. Also considering overfishing, is it possible to cultivate the algae and feed it to farmed fish, shut down wild fisheries for at least 20 years, or eat the algae directly in the form of seaweed? 166.216.159.155 (talk) 16:35, 4 March 2017 (UTC)

To my knownledge Fishfarms only use Carnivore species of fish because Herbivore grow slower and need a much higher volume of food as vegitarian food has allot less Nutrition then animal or insect tissue. It should be possible to cultivate/farm algea and feed a fishfarm with fitting fish but that would not be effective. The only exeption are clam-farms, as they dont need to be fed but they also need more time to grow.

You could eat algae directly. Not all but most species of "seaweed" actually make a great healthy meal, if they grew in a clean enviroment ofcourse. --Kharon (talk) 20:35, 4 March 2017 (UTC)

P.S.: I just noticed we even have an article about it: Edible seaweed --Kharon (talk) 20:50, 4 March 2017 (UTC)

http://www.nordicnaturals.com/en/Products/Product_Details/514/?ProdID=1654 Count Iblis (talk) 22:34, 4 March 2017 (UTC)