Wikipedia:Reference desk/Archives/Science/2019 October 17

= October 17 =

Bacopa Monnieri
I got a bottle of this stuff in mail one day, charge free. Never heard about it. A quick check showed that people claim various cognitive benefits. Is anybody aware of any solid research on this plant? Thanks, - AboutFace 22 (talk) 02:02, 17 October 2019 (UTC)
 * Here's what WebMD has to say: I notice several "might" qualifiers in there. ←Baseball Bugs What's up, Doc? carrots→ 03:47, 17 October 2019 (UTC)
 * FWI Bacopa monnieri Anton 81.131.40.58 (talk) 08:13, 17 October 2019 (UTC)

Touch and death
They say that a baby will die if it is provided with food, water, etc but never given human touch. Is this true of other animals? Temerarius (talk) 02:27, 17 October 2019 (UTC)


 * Can you supply any documented information about what “they” say in relation to human infants? It sounds like a myth. Dolphin ( t ) 02:36, 17 October 2019 (UTC)


 * There have been experiments with monkeys that show they do need a "mother", but that can just be a warm blanket with a monkey face mask, it doesn't need to be an actual monkey. And, of course, some animals are independent from birth, like sea turtles, so they don't need any such contact. Other animals that do need mothers can attach themselves to other species, in a process called imprinting. SinisterLefty (talk) 05:34, 17 October 2019 (UTC)


 * I presume you are referring to Harry Harlow's experiments in raising rhesus monkeys with various types of surrogate mothers. Whether these studies show that monkeys "need" a mother depend on what you mean by "need". In contrast to the claim in the OP, the monkeys raised without mothers did not die, although they were psychologically abnormal. I doubt that any similar study has ever been done with human babies, so I don't see how the claim in the OP that babies die without touch could be supported. CodeTalker (talk) 22:30, 19 October 2019 (UTC)

1st, 2nd law of thermodynamics and the rest
Are the first and second laws of thermodynamics somehow more important or for some reason to be singled out from the rest:

In University Physics by Young's index:


 * Thermodynamics
 * 1) Temperature and Heat
 * 2) Thermal Properties of Matter
 * 3) The First Law of Thermodynamics
 * 4) The Second Law of Thermodynamics

Only the first two are studied, at least in a separate chapter. Is that normal for a general textbook? C est moi anton (talk) 08:50, 17 October 2019 (UTC)
 * The reason why those two are singled out is that they have the greatest implications for most people. The first law is the law of conservation of energy and the second is the law of increasing entropy.  The third law, which is merely a definition of zero entropy; is ultimately not that necessary since we can define a "zero" point anywhere and the other laws still work fine, after all we deal with concepts like energy and enthalpy just fine even though we have no meaningful "zero" point for those values, we just deal in "ΔE" and "ΔH", which is all we need to know anyways.  The zeroth law of thermodynamics is a rather unsurprising law describing the transitive nature of energy; that is if state A is in equilibrium with state B, and state B is in equilibrium with state C, than A is in equilibrium with C.  It's really only necessary to define thermodynamics as transitive for the sort of mathematical formalism necessary to prove certain other mathematical relationships, but it's not really all that broadly necessary for anything else.  The first and second, however, have HUGE implications for the behavior of energy in the universe, which is why we focus on them so much.  -- Jayron 32 11:10, 17 October 2019 (UTC)

Dating ancient artifacts that do not contain carbon
Would radiocarbon dating be of any indirect use here? That is, if they find a clay table buried with a bone, they can speculate that the former is at least as old as the latter. Are there direct methods for dating, at least for man-made artifacts? The relevant article Dating in archeology only mentions the existence of direct methods, but does ceramic, swords or glass deteriorate in a way that can be measured? C est moi anton (talk) 10:22, 17 October 2019 (UTC)


 * I don't think that any of those materials can be dated directly. Dating in archaeology, like geology, mainly relies on relative dating. The stratigraphy of the site is determined and then any dateable materials are analysed (using the methods listed in the article that you linked to) to provide fixed points in the site's chronology. The artefacts are then dated by comparison with these fixed points. Mikenorton (talk) 11:04, 17 October 2019 (UTC)
 * Apparently lead can be dated directly in some circumstances - as here. Mikenorton (talk) 11:25, 17 October 2019 (UTC)


 * Iron objects contain carbon:) See for an article about dating iron objects. DMacks (talk) 13:37, 17 October 2019 (UTC)
 * Wouldn't clay also contain some carbon? C est moi anton (talk) 16:15, 17 October 2019 (UTC)
 * Clay tablets were generally dried rather than fired so any carbon in them would not record the date of the tablets themselves. Most clays anyway don't have a significant organic content. Mikenorton (talk) 16:46, 17 October 2019 (UTC)


 * Ceramics, including clay if fired, may be datable via Thermoluminescence dating or by Rehydroxylation dating. Some clay tablets were fired not intentionally but when the building storing them was burned down, as mentioned in the article linked by Mikenorton immediately above.
 * Some carved stone may be datable by Luminescence dating.
 * A particular artifact, irrespective of its nature, might be datable by various Geochronology techniques if it has been preserved in an applicable context, as implied in the OP and first response. {The poster formerly known as 87.81.230.195} 90.200.41.118 (talk) 17:24, 17 October 2019 (UTC)


 * Here's an article about using uranium–thorium dating of minerals to determine the age of cave paintings. Another article lists a few other methods. These non-carbon isotope measurements are indirect in that they analyze the properties of something found along with the artifact. The reason for using indirect methods depends on the material. For example, there are problems associated with dating the carbon in iron objects like swords. This paper lists some methods used for different non-carbon dating techniques for glass and pottery. (it is out of date and also behind a paywall) --mikeu talk 23:57, 20 October 2019 (UTC)

Are one-to-one comparisons between superlative physical traits of small animals versus large animals "fair"?
There's a new animal show on TV (Little Giants) that focuses a great deal on measuring some physical feat of a small animal and then breathlessly exclaiming about how if you scaled the feat up to human sized it would be so astounding. For example, that the giant horned lizard shoots toxic blood out of its eyes and the 3-foot distance it squirts the blood would be like it squirting the blood five football fields at human size (making up the numbers to give you an idea of what I'm talking about; not verbatim from show); or that the mouse lemurs' X-foot jumps between trees is like a human jumping Y feet, and so on (wow!).

I don't have the science background to back up my nagging feeling that the comparisons they're exclaiming over are not really kosher. Is this one-to-one comparison "fair", or is there some factor of "economies of scale" or something like that, that explains why these scaling comparisons are not as incredible as they seem? Does it really work like that? Or would, for example, a human scaled down to a tiny size also be able to throw much farther in comparison to their normal size because of the way the physical world works at the small versus large scale? Lady in polka dot (talk) 23:10, 17 October 2019 (UTC)


 * You are right to be skeptical. See square-cube law and, linked from that, allometry. --76.69.116.4 (talk) 23:49, 17 October 2019 (UTC)
 * In the case of squirting, increased air resistance from a high initial speed would also be a big factor. I think you can forget about crossing football fields with a small liquid. It probably evaporates or disperses long before the speed is high enough. The square–cube law is also a factor if you try to compare structures built by small animals like mound-building termites. They may be impressive but it's not like humans making skyscrapers. And there is a reason dragons are myth and real flying animals are small. They cannot compete with airplanes on fair terms. PrimeHunter (talk) 14:11, 19 October 2019 (UTC)