Wikipedia:Reference desk/Archives/Science/2020 May 1

= May 1 =

Human psychology during pandemics
From a human psychology point of view, why are so many aspects of the current situation divisive amongst people across the world regardless of their background? Have any studies been done in the past to look at this? Clover345 (talk) 14:46, 1 May 2020 (UTC)
 * Examples? I'm guessing you mean religious vs. atheistic viewpoints? Like, "punishment from God" to nothing peculiar at all? But what other answer could you be looking for besides genetics. 67.175.224.138 (talk) 14:55, 1 May 2020 (UTC).
 * Genetics is not at all likely to be the answer or even what they are asking for if they are asking a psychology question. --OuroborosCobra (talk) 15:23, 1 May 2020 (UTC)


 * I'm not sure our original question is specific enough to receive a proper response; but when I find myself wondering about the softer sciences, I start by browsing the collection at JSTOR, a free digital library collection that provides a lot of scholarly research.
 * Via JSTOR: The Crowd in History: Some Problems of Theory and Method (Social History, 1978). "What might be called crowd history as a field of study in its own right has, rather surprisingly, received very little critical comment."  Perhaps the interested reader will be able to take a deeper look into further materials.
 * For regular readers of AAAS's journal Science - rather more likely to overlap with our regular contributors on the Science Reference Desk - you might find this article very exciting: The Lessons of the Pandemic (Science, 1919). Like many other Science articles in the older archives at JSTOR, it is available at zero cost.
 * If I may editorialize, a bit: well written scientific analysis, from any century, provides an astonishing clarity that - to me - proves beyond reasonable doubt that despite the progress of a few scientific minds in a very few select areas of specific understandings of our natural world; and in spite of amazing the proliferation of advanced technology in daily life - the overwhelming majority of the knowledge that we have about our natural world has truthfully not changed very much at all since the so-called Dark Ages - because the overwhelming majority of knowledge is, and always shall be, embodied in the minds of very scientifically-uneducated individuals who constitute the so-called crowd.
 * Nimur (talk) 16:22, 1 May 2020 (UTC)


 * One thing that can be observed is that some people who are materially better off do not appear to fully grasp the economic hardship on others resulting from the closures. Economic relief may be denied or only given grudgingly and in insufficient amounts. The question when to re-open in what phases depends on risk assessments; these will be based on the information one receives, which may be rather different in different bubbles. The issue also depends on the relative values assigned to human life and health versus material wealth, which also may be based on one's ideology. --Lambiam 16:39, 1 May 2020 (UTC)
 * That's common to pretty much every economic downturn, including the Great Depression. 89.172.65.59 (talk) 04:25, 2 May 2020 (UTC)

Source of names for 4 mild human coronaviruses?

 * Human coronavirus OC43 ?
 * Human coronavirus HKU1 Hong Kong ?
 * Human coronavirus 229E ?
 * Human coronavirus NL63 Netherlands? -- Jeandré, 2020-05-01t20:17z
 * You should read discovery papers. Ruslik_ Zero 21:00, 1 May 2020 (UTC)


 * In most cases these are just the labels used in the labs that isolated and described the viruses to label the samples from which the strains were isolated. Each research group had its own labelling method. The "OC" in "OC43" stands for "organ culture", while "43" is probably a meaningless sequence number. Described in: McIntosh K, Dees JH, Becker WB, Kapikian AZ, Chanock RM. "Recovery in tracheal organ cultures of novel viruses from patients with respiratory disease". Proc Natl Acad Sci USA 1967;57:933–40. "HKU" is the abbreviation for the University of Hong Kong where the strain was isolated. Strain 229E was isolated by Dorothy Hamre and John Procknow and described in: Hamre, D., and J. J. Procknow, Am. J. Epidemiol. 83:238 (1966). Perhaps their publication explains the label, but I suspect it was simply the label of one lab sample among many, labelled ..., 228A, 228B, ..., 229D, 229E, 229F, ... . And "NL" is obviously the Netherlands.

Does pure ammonia expand when it freezes like water does?
Water, H2O, expands when it freezes. It has a different structure than NH3, because it only has 2 Hs, but isn't it frequently like H3O+, which might resemble NH3 structure?144.35.20.92 (talk) 20:44, 1 May 2020 (UTC)
 * No as far as I know. Ruslik_ Zero 20:55, 1 May 2020 (UTC)


 * Our article on Ammonia gives among its properties densities of 681.9 kg/m3 at −33.3 °C (liquid) and 817 kg/m3 at −80 °C (transparent solid). As the mass of a fixed number of ammonia molecules will not change as the stuff freezes, this implies that a liquid cubic meter of ammonia will take up a volume of 681.9/817 m3 = 0.834 m3 when frozen. --Lambiam 22:41, 1 May 2020 (UTC)


 * I had asked this question before about hydrogen peroxide, which is probably more similar to water than ammonia. And our article doesn't have its density as a solid, or talk much about it. People say this is a result of hydrogen bonding, but hydrogen bonding alone doesn't answer the question. As H2O2 and NH3 are both examples of hydrogen bonding. On a separate topic, I did have a list of other compounds that are like water with its density, I'ma look for it. 67.175.224.138 (talk) 00:38, 2 May 2020 (UTC).


 * The phase diagrams in this article (pdf) imply that solid ammonia is denser than liquid ammonia.  Higher pressure favors the denser phase, and solid ammonia is above the adjacent liquid ammonia on the pressure-temperature phase diagrams.--Wikimedes (talk) 04:31, 2 May 2020 (UTC)


 * In addition to the above, it is worth noting that water is not "frequently like H3O+. At room temperature, for example, the concentration of H3O+ = 10-7 M. For perspective, water itself has a "molarity" of about 55.5 M. That means that in a given volume of water, only about 1.8*10-7% of the molecules will be H3O+. -OuroborosCobra (talk) 19:34, 2 May 2020 (UTC)


 * There is a one-sentence section at Freezing that lists just two substances that expand when they freeze. The other one is bismuth.  But it doesn't say how rare or common the phenomenon is (I've formed the impression that it's pretty rare, but I don't remember where I picked that up from, so don't believe me), or what sort of chemical properties cause it, or anything.  I've just flagged the section, rather appropriately, as needing expansion. --76.71.5.208 (talk) 23:18, 2 May 2020 (UTC)


 * Plutonium does as well. Plutonium last paragraph. But it is a rare phenomenon.--Wikimedes (talk) 03:46, 4 May 2020 (UTC)

How are inorganic archaeological artifacts dated?
Of course, any object containing the appropriate elements can be dated via isotope dating, but how do archaeologists date inorganic objects with any specificity? If a stone tool or fragment of pottery is found, is it simply dated according to other, more easily determinable nearby objects? Is it as simple as assuming a constant rate of wear-and-tear? Are there other convenient isotopes which decay at a useful time scale? Surely there are sophisticated techniques I am unaware of, and would be interested in hearing about. Opossum421 (talk) 23:27, 1 May 2020 (UTC)


 * When objects are found in an archaeological excavation, their context is recorded, particularly where they lay in the site's stratigraphy. Other datable objects are used to establish the age of the different layers and thereby the objects found within them. Mikenorton (talk) 00:14, 2 May 2020 (UTC)


 * Radiometric dating discusses several isotopes that are used in dating.--Wikimedes (talk) 04:17, 2 May 2020 (UTC)
 * Chronological dating contains many dating methods. Luminescence dating is an interesting one.--Wikimedes (talk) 04:20, 2 May 2020 (UTC)
 * As others have basically said, there are a lot of dating methods, and (ideally) more than one is used so as to validate results. When no method for a specific artifact is available, they may have to make use of referencing something else. So, for example, you find an arrowhead on its own made of a particular material and particular design, but for some reason you can't specifically date that arrowhead. You then look to see if other arrowheads of the same material, same design, and in roughly the same region have been found. Perhaps one was found together with other items, including a material that could be dated (hair? wood? there are tons of materials that we can date). Those materials then form a reference to date the arrowhead they were found with, and the arrowhead you found off on its own can be assigned a similar date based on referencing. It's not perfect, but it is better than nothing. This type of reference dating is done with extreme care and, given other evidence, can be revised. --OuroborosCobra (talk) 17:09, 3 May 2020 (UTC)