Wikipedia:Reference desk/Archives/Science/2020 December 13

= December 13 =

What's the least soft thing you could cut with an atomically perfect diamond without breaking a bond?
2. If gem trade perfect diamonds (AKA 10x loupe) were big and cheap instead of about an inch wide at best and 8 digits of dollars could you make a practical all-diamond razor-sharp point and edge food knife blade with lasers? How much twisting or bending force could it take and could you use it as a heavy cleaver or nutcracker and stab pouring holes in a coconut with 1 stab per hole side with it or is the limit closer to cutting tofu? Sagittarian Milky Way (talk) 23:34, 12 December 2020 (UTC)
 * To answer what I think is your second question, diamond would make a terrible cleaver or mallet. As our article Material properties of diamond says, "Unlike hardness, which denotes only resistance to scratching, diamond's toughness or tenacity is only fair to good. Toughness relates to the ability to resist breakage from falls or impacts. Because of diamond's perfect and easy cleavage, it is vulnerable to breakage. A diamond will shatter if hit with an ordinary hammer." CodeTalker (talk) 19:26, 13 December 2020 (UTC)
 * Is it at least harder to break than a cheap glass blade? Sagittarian Milky Way (talk) 16:12, 14 December 2020 (UTC)
 * Diamond knife suggests that the last thing one needs to use is gem-quality diamonds! Mike Turnbull (talk) 12:35, 14 December 2020 (UTC)
 * Right, if you want a knife with diamond's hardness you just take a metal knife and encrust with crushed junk diamond. If you want to cut tofu with a novelty bling you go to a parallel Earth where top grade (D flawless) stones many times the world record width exist and cut a blade shape with lasers. Then you do as much of your kitchen work with it as you can without cracking it till the novelty wears off or maybe it might even never get old. Sagittarian Milky Way (talk) 16:09, 14 December 2020 (UTC)

Cannabis plant does itself adjust/move how the sunlight runs
Hello there. I have seen on a balcony YouTube video that the planted cannabis plants do move their selves to get as much light as possible and also "fall" themselves asleep after the sunset. I am interested which molecule / pheromon / nerves recipe does inside the plant is activated to make the plant align to the sunlight the same way sunflowers are able to turn in circle to align to the sunlight? Where do these nerve impulses came from, how are they made and where does the plant get its power to "wake up", turn around, and fall again asleep? Does the minimum of a light is enough for a plant to produce enough Adenosintriphosphat to wake up and does the plant consume this ATP to align or does another recipe is used for this and ATP is only for growing, getting bigger and producing seeds? --2A02:A312:6041:E900:F4BE:8393:F751:85B0 (talk) 01:21, 13 December 2020 (UTC)
 * As the article Photoperiodism describes, Cannabis is a "short day" plant. Phototropism also has some answers. Abductive  (reasoning) 01:47, 13 December 2020 (UTC)
 * It's plant hormones like auxin, as the above articles discuss. You know an adrenaline rush? That's hormones. Same principle, just different chemicals. The energy plants use is ultimately from light, which they capture via photosynthesis, store as chemical energy, then "burn" in their mitochondria to power processes such as synthesizing hormones, just as in your body. --47.152.93.24 (talk) 02:51, 13 December 2020 (UTC)
 * Don't most non-woody plants tend to lean toward the sun? ←Baseball Bugs What's up, Doc? carrots→ 04:08, 13 December 2020 (UTC)
 * Our articles Heliotropism and Phototropism may shed some light on the question, but do not give a definive answer as to the number of species or proportion of all plants that exhibit them. {The poster formerly known as 87.81.230.195} 2.122.56.237 (talk) 04:42, 13 December 2020 (UTC)
 * Animals and plants alike use ATP for basically all processes that require energy. Plants use it for the transport of ions throughout the plant, which is used for rapid plant movement, but also for the twisting of leaf stems of slow-moving plants that can be made apparent by time-lapse photography. The physics underlying such movement is that of cells getting higher or lower turgor pressure due to water moving in and out of these cells by osmotic action in response to changes in the ion concentrations. --Lambiam 13:33, 13 December 2020 (UTC)

Psychology
Decribe Maslow's hierarchy of needs stating how it can be applied to improve learning in Kenyan schools — Preceding unsigned comment added by 102.167.83.155 (talk) 08:26, 13 December 2020 (UTC)


 * Do your own homework. This will help: Maslow's hierarchy of needs.Graham Beards (talk) 08:56, 13 December 2020 (UTC)


 * And have a read of Do your own homework. HiLo48 (talk) 08:57, 13 December 2020 (UTC)
 * In addition to various other no-nos about the ref desks, there should be one that says we will not answer "questions" which read like "demands". ←Baseball Bugs What's up, Doc? carrots→ 09:14, 13 December 2020 (UTC)
 * That might involve telling the IP editor's teacher to not set homework questions that read like demands. HiLo48 (talk) 09:22, 13 December 2020 (UTC)
 * There is some sort of template which identifies a given IP as belonging to a school. Such a caution could be included in that template. ←Baseball Bugs What's up, Doc? carrots→ 10:55, 13 December 2020 (UTC)
 * The OP's 'question' read like it was taken straight from the exercise set by a teacher/lecture. LongHairedFop (talk) 11:00, 13 December 2020 (UTC)
 * For sure. ←Baseball Bugs What's up, Doc? carrots→ 11:31, 13 December 2020 (UTC)
 * Assuming Maslow's hierarchy of needs can be applied to improve learning in the schools of country X, then answering the "how" question requires a good understanding of country X and its educational system – unless the answer is embedded in the class notes of a school textbook and merely needs to be reproduced. If students are malnourished and lack energy, then surely a well-administered school lunch program can offer some improvement. Developing the ability of critical thinking is hardly stimulated in many countries' educational systems, but is important for self-actualization – as well as for a country's vitality and resilience. --Lambiam 13:04, 13 December 2020 (UTC)

Zebra
Zebra currently says "Striping patterns are unique to an individual and heritable". This looks contradictory to me: if they are heritable, then they could not be unique to an individual, because an offspring would inherit the same pattern as the parent (and vice versa). Please clarify if anything, thanks. 212.180.235.46 (talk) 22:06, 13 December 2020 (UTC)
 * Compare "A human's facial features are unique to an individual and heritable." Heritable does not mean replicated exactly. HenryFlower 22:15, 13 December 2020 (UTC)


 * It seems kind of poorly worded. Presumably, what they are trying to say is that stripes are heritable, and striping patterns are unique to an individual. ←Baseball Bugs What's up, Doc? carrots→ 22:47, 13 December 2020 (UTC)
 * Ok, that makes sense then. 212.180.235.46 (talk) 00:21, 14 December 2020 (UTC)


 * There is more to it than that having stripes is heritable. Some zebras have thin stripes, others thick stripes, and some thin stripes on some parts of their body but thick on other parts. These distributional patterns are heritable and characteristic for the zebra species. For example, the mountain zebra has thin stripes except on its hind quarters, where they are rather thick. The (threatened) Grévy's zebra has thin stripes almost everywhere, a bit thicker in its neck and one very thick stripe down the middle of its back, along the length and extending into the tail. The mountain zebra has transversal stripes there. A zebrologist can determine the species and often the subspecies purely from this distributional pattern. Zebras also recognize their conspecifics this way. There is still an immense variety of possible concrete, individual patterns that conform to the distribution of a specific distributional pattern, just like no two fingerprint arches from different fingers are exactly alike. --Lambiam 11:32, 14 December 2020 (UTC)