Wikipedia:Reference desk/Archives/Science/2016 June 8

= June 8 =

Minimum spring outer diameter for a given wire diameter
Is there a formula, table, or some sort of back-of-the-envelop approximation for calculating the minimum spring outer diameter for a given wire diameter?

Let's say the spring wire diameter is 1 mm. A 5 mm outer diameter spring is possible given this wire size; but a 4 mm outer diameter spring would not be possible. Thus the minimum spring outer diameter is somewhere between 4 mm and 5 mm. How do I go about calculating or approximating this minimum outer diameter? Johnson&#38;Johnson&#38;Son (talk) 07:34, 8 June 2016 (UTC)


 * Yes. I use a slide rule for this.  It's a specialised slide rule, given away some time in the 1970s as a design aid by a spring winding factory.  If you talk to any spring maker, they will help you out with this - either with a table in their catalogue, a simple spreadsheet or computer program, or maybe even a slide rule. Andy Dingley (talk) 11:39, 8 June 2016 (UTC)
 * Wikipedia articles are Coil spring and Spring (device). Here is an American spring catalog search site which converts inch measurements to mm. The extended search for extension springs made of 1.0414 mm diameter wire finds minimum outer diameter 5.9436 mm in stock. AllBestFaith (talk) 13:21, 8 June 2016 (UTC)


 * Talk to a manufacturer. Bear in mind they are talking about what is easy to make on their standard machines, so far as I know an ID of almost zero would work as a spring, but would be very hard to make (3d print it but that will have horrid material properties compared with spring steel). Now, the usual equations won't work, you'd need to FEA it or do some hard maths. The fatigue life, in particular, is likely to be horrific, as the most central fibre is almost in tension and compression. Greglocock (talk) 02:35, 9 June 2016 (UTC)
 * I talked to a manufacturer and that's where they told me that for a 1 mm diameter wire, 5 mm OD was feasible but 4 mm OD wasn't. They weren't able to tell me exactly what the minimum was, other than "somewhere between 4 mm and 5 mm“. Johnson&#38;Johnson&#38;Son (talk) 10:07, 9 June 2016 (UTC)
 * There's a minimum interior diameter because otherwise the strain becomes excessive.
 * This is one reason for the use of Belleville washers, rather than coil springs. Andy Dingley (talk) 11:04, 9 June 2016 (UTC)

Question about sperm temperature
A mans nutsack is on the outside of the body because sperm die if they are too hot, right? Otherwise they'd be kept safe inside his body instead of dangling dangerously outside. So how come when he puts his sperm inside the womans belly to make her pregnant the sperm don't die from the internal heat of the woman? (I assume men and women measure the same temperature?)

Basically how come the sperm die at body temperature inside the man, but don't die inside the woman? 200.94.21.194 (talk) 18:42, 8 June 2016 (UTC)


 * It's not that sperm die at body temperature; it's that spermatogenesis doesn't work as well. Sperm also travel through the male's body during ejaculation (note: NSFW images in article), so even before entering the vagina they already encounter higher temperatures. (Also, "nutsack"? Maybe use "testicles" on the science desk?) --71.110.8.102 (talk) 22:04, 8 June 2016 (UTC)
 * Maybe the OP was talking about this kind of thing. And speaking of "spilling seed", the OP should be advised that the methods illustrated in that secnd article are unlikely to result in impregnation. ←Baseball Bugs What's up, Doc? carrots→ 22:29, 8 June 2016 (UTC)


 * Très amusante, except that those are not nuts. Richard Avery (talk) 06:38, 9 June 2016 (UTC)
 * That's OK, this is even more illustrative. ←Baseball Bugs What's up, Doc? carrots→ 06:44, 9 June 2016 (UTC)


 * This is an interesting one - I'll need more time to figure it out, if I ever do. There are forum postings available via  and  that shed some light.  It is noted that elephants are "primary testicond" animals, i.e. that have never had testes descend.  This is somehow used to try to claim that they evolved for aquatic life ... even though they never evolved to have a scrotum in the first place ...  I would like to see more evidence of basal "primary testicond" mammals before I try to impose any sense on that, but in any case the testicles are definitely way up inside, like ovaries -- see .  So it is not impossible to produce sperm inside the body.  But is it more difficult?  So far the most appealing of the speculations at those forums I saw was the notion that since sperm are highly specialized, stripped-down cells, they need to damp down their metabolism to live longer, i.e. by being cooler.  But I have no idea if that has any truth to it. Wnt (talk) 14:46, 9 June 2016 (UTC)


 * I'm not sure what you're saying about the elephant exactly. What you linked says the same thing as other sources: elephants have internal testes because they're descended from aquatic ancestors. Aquatic mammals have internal testes to reduce drag. Mammals with internal testes cool them below body temperature using blood vessels that bring cool blood from the skin. --71.110.8.102 (talk) 15:31, 9 June 2016 (UTC)
 * I often wonder why lists/discussions of mammals with internal testicles miss out the Hyrax. This small lagamorph-sized animal tends to rule out that internal testes might be due to some animal-size/thermoregulation issue.  I have often wondered why, if some mammals can reproduce successfully with internal testes, do not all mammals have internal testes.  After all, I would have thought the selection pressure on catching your scrotum on a branch would have been very high given that a split scrotum would likely reduce your fitness to zero. DrChrissy (talk) 16:49, 9 June 2016 (UTC)
 * Well, a hyrax is more or less an elephant, at the level of generalization we're using (they're both Afrotheria). Hyraxes have body temperature 35 to 37 C  and our article on elephant says they're 36 C, so both are just a little cooler than humans (but don't tell them that).  And at least the Testicles article only talks about special cooling in aquatic mammals that have re-evolved internal testes, not in these guys.  Plus, birds endure even hotter body temperatures with internal testes.  The rhinoceros is another one of the primary testiconds (but within Boreoeutheria), and they have body temperature of 100 F .  So it seems like we might have to cast our gaze elsewhere, like basal mutation rate ... sigh, what are the odds I can find the basal mutation rate of a rhinoceros...?  Well, I'll be -- found something pretty close, anyway, here:   They actually represent one of the slower-varying clades, as is Xenarthra, another primary testicond.  But humans are also slow.  I'm thinking lifespan may be a confounder here, but at first blush I have to say, I'm not buying the idea that internal testicles impose some huge mutation burden. Wnt (talk) 19:56, 9 June 2016 (UTC)
 * Sperm competition can shed some light on why many/some mammals have a sort of Red Queen's Race going on with testicle size/sperm output, and external testes may be part of that. But sexual selection and and cultural/behavioral stuff also clouds this for anything but the most solitary of species. Also evolution of anisogamy is a distant symmetry breaker that I think has shaped a lot of this evolution.  SemanticMantis (talk) 15:00, 10 June 2016 (UTC)

Baby spiders
I recall reading back in the '80s in The Encyclopedia of Igorance (eds: Ronald Duncan, Miranda Weston-Smith) about an experiment involving baby spiders with results that could not be explained by known mechanisms. The experiment was simple: hatch spiders in a controlled environment, devoid of any food or water source. Soon their mass and volume will greatly increase (I forget the stats) -- it was (is?) unknown how they were able to create the complex molecules presumably from "thin air". --Has this since been explained? ~ 107.15.152.93 (talk) 20:04, 8 June 2016 (UTC)
 * I don't know about that study, but I remember reading that some baby spiders catch pollen and dust on their webs, and that can sustain them. Graeme Bartlett (talk) 22:34, 8 June 2016 (UTC)
 * Spider cannibalism both of the mother and of fellow hatchlings can be a factor, so I would be suspicious that the experiment did not take an accurate count of the number of spiders at beginning and end. Wnt (talk) 14:50, 9 June 2016 (UTC)

How does capillary phenomena play a role in eye irrigation and nosebleeds?
1) I have read the following phrase in the book "Nano-Surface Chemistry" (p.289) "Capillary phenomena are also essential in tribology and in many biological systems, such as blood circulation and eye irrigation". How does it plays role in eye irrigation?  2) In a English-Spanish I've read: "Nosebleeds are caused by the rupture of a small blood vessel called a capillary in the nose." Is there any relation between the capillary phenomena to the rupture or to the mechanical going of the blood outside? 93.126.88.30 (talk) 23:37, 8 June 2016 (UTC)
 * The word "capillary" originally meant "pertaining to the hair" . Capillary blood vessels were so named because they are very thin, like hair. Very thin glass tubes are also called capillary tubes for the same reason.  Capillary phenomena or capillary action is the tendency for liquid to flow into narrow spaces, first noticed in glass capillary tubes.  So capillary action is not really related to capillary blood vessels except that they both come from the same root word.  CodeTalker (talk) 02:00, 9 June 2016 (UTC)
 * But I saw many sources (except of this that I've already brought) which claims that capillary phenomena does relate to blood circulation. What is the explanation? 93.126.88.30 (talk) 11:28, 9 June 2016 (UTC)
 * As mentioned above, capillary action occurs in many situations, but if your "many sources" claim that it is the main cause of blood flow in capillary blood vessels, then there's something wrong.   D b f i r s   09:40, 10 June 2016 (UTC)
 * As for the first question, tears form a thin film on the eyeball when they're dragged across by the eyelids. The various components of tears play a role in maintaining this film, and the physics are somewhat complex. The film is essential so tears coat the whole eye and don't evaporate away quickly. --71.110.8.102 (talk) 03:29, 9 June 2016 (UTC)

Elements 119-120
Now that official names of elements 113-118 have been proposed to become standard, can anyone find out what's going on with elements 119 and 120 (the elements of the next row of the s-block)?? By the end of 2016 some of the labs should start working on trying to create these elements whatever way they can. Georgia guy (talk) 23:43, 8 June 2016 (UTC)
 * The story so far is at ununennium and unbinilium. I imagine that now that 113–118 have IUPAC approval (despite having failed miserably at guessing the names that weren't revealed well in advance), the labs will indeed make another push for 119 and 120. Whether they will work is another story! Double sharp (talk) 12:18, 9 June 2016 (UTC)

Does human body have a surfactant in another place in the body except of in the lungs?
or it is the only one surfactant in the body? 93.126.88.30 (talk) 23:49, 8 June 2016 (UTC)
 * I expect there are many, and many compounds will have some surfactant behaviour even if it's not their primary function. One obvious one leaps out though, and that's bile, which emulsifies fats as part of the digestive process. Andy Dingley (talk) 01:11, 9 June 2016 (UTC)
 * How about the cell membrane of every cell in the body? EdChem (talk) 14:51, 9 June 2016 (UTC)