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{{atop|result = We don't answer requests for medical advice --[[User:Jayron32|<span style="color:#009">Jayron</span>]][[User talk:Jayron32|<b style="color:#090">''32''</b>]] 12:13, 17 November 2022 (UTC)}} |
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My mom has [[Dysmenorrhea|painful menstrual cycles]] every other one (her average [[Menstrual cycle|menstrual cycles]] are about 30.5 days long. One menstrual cycle, she could barely feel it, but the other one seems to be the "hurtful" one. She takes a [[Paracetamol|Midol]] whenever those cycles come. Why is that, I wonder? [[Special:Contributions/67.215.28.226|67.215.28.226]] ([[User talk:67.215.28.226|talk]]) 04:52, 17 November 2022 (UTC) |
My mom has [[Dysmenorrhea|painful menstrual cycles]] every other one (her average [[Menstrual cycle|menstrual cycles]] are about 30.5 days long. One menstrual cycle, she could barely feel it, but the other one seems to be the "hurtful" one. She takes a [[Paracetamol|Midol]] whenever those cycles come. Why is that, I wonder? [[Special:Contributions/67.215.28.226|67.215.28.226]] ([[User talk:67.215.28.226|talk]]) 04:52, 17 November 2022 (UTC) |
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:Questions asking for medical advice, which this is, are not allowed here. Sorry. --[[Special:Contributions/174.89.144.126|174.89.144.126]] ([[User talk:174.89.144.126|talk]]) 05:33, 17 November 2022 (UTC) |
:Questions asking for medical advice, which this is, are not allowed here. Sorry. --[[Special:Contributions/174.89.144.126|174.89.144.126]] ([[User talk:174.89.144.126|talk]]) 05:33, 17 November 2022 (UTC) |
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:What has her doctor said about this? ←[[User:Baseball Bugs|Baseball Bugs]] <sup>''[[User talk:Baseball Bugs|What's up, Doc?]]''</sup> [[Special:Contributions/Baseball_Bugs|carrots]]→ 12:11, 17 November 2022 (UTC) |
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November 10
Benzene ring
Many, many moons ago (I would have been about 15) our chemistry teacher told us about the benzene ring. But because my mathematics was abysmal, bordering on non-existent, I soon came to the unhappy conclusion that I was never going to realise my boyhood dream: to be some sort of chemist, preferably of the organic type. Even the concept of a mole did my head in. About a decade later (having pursued a somewhat different career path) I came across Kekulé's fabled constitutional wander, and began to understand how utterly important his insight was.
Can anyone explain in plain language why the benzine ring appears to be so fundamental to org. chem.? Almost every diagram of any complex molecule I come across on WP seems to include it almost as a matter of course. What makes it so bindable, as it were? Is there anything else quite so widespread?
Our teacher also suggested The Peptide Link™ as the name of a funky jazz beat combo, but it seems never to have taken off. MinorProphet (talk) 02:24, 10 November 2022 (UTC)
- Articles: cyclic compound, aromatic compound, aromaticity. Very technically, a "benzene ring" is only C6H6. There are lots of compounds containing a ring structure that isn't a "benzene ring", although they can be modeled as starting from a benzene ring and then substituting atoms of the ring with other things. Aromatic rings, of which the benzene ring is an example, are very stable chemically because the electrons of the atoms in the ring "overlap" and are delocalized throughout the ring, in a great demonstration of quantum chemistry and the wave–particle duality of electrons. This confers increased stability, which is often a desirable property. Not all "common" molecules contain ring structures. For instance carbohydrates often can adopt a cyclic form, but can freely convert between this and a linear form. Fatty acids are linear molecules, and only some of the proteinogenic amino acids contain rings. --47.147.118.55 (talk) 05:22, 10 November 2022 (UTC)
- Interestingly, the part of the article on the history of benzene's structure was improved greatly within the last month thanks to Leyo, who took the trouble to upload to Commons the original diagrams as published in the late 1800s. Our Talk Page discussion is WT:WikiProject Chemistry#Historic benzene structures. One reason organic chemists focus on benzene is because its structure is used to teach the general principles both of aromaticity and reaction mechanism, where many fall in love with explanations based on the curly arrow. The use of benzene as a part-structure in drugs and agrochemicals largely stems from intermediates containing it being readily available and cheap as a byproduct of petrochemical production. Mike Turnbull (talk) 12:18, 10 November 2022 (UTC)
- The importance of benzene and its structure is the presence of the delocalized pi electrons; it was the first structure where such a thing was shown to exist; it explains a LOT of the properties of benzene, which are paradoxical. Benzene is highly unsaturated, meaning that it has excess electrons and thus in theory should easily make bonds to other atoms readily. Usually, unsaturated hydrocarbons are more reactive than saturated ones, because there is a local area of electron density in the molecule; basically things that have double bonds in them have a concentrated area of electron density that electrophiles can easily form bonds to. And yet benzene is essentially as unreactive as a saturated alkane. How can one have an unreactive molecule that is so unsaturated? The reason is that the "extra electrons" in benzene are delocalized and spread evenly across the ring structure, meaning there is no local area of high electron density; so nothing for electrophiles to "grab on to". Recognizing that this could happen was the key to opening up entire new areas of organic chemistry, we call this aromaticity, and such compounds are called aromatic compounds (the etymology of the terminology escapes me, but the use of the word aromatic in organic chemistry has basically nothing to do with odor). If you need me to go more into what "pi electrons" are I can, but really as long as you know that the "extra" electrons in the highly unsaturated benzene ring are not concentrated between any particular atoms in the ring, but are instead delocalized and spread evenly all over the molecule is the key to the situation. I hope that all works for you. --Jayron32 13:15, 10 November 2022 (UTC)
- The word "aromatic" does have its origin in the odor of such compounds. See Aromaticity#The term "aromatic". It was used in that sense by August Wilhelm von Hofmann in 1855, before the relevant structures were confirmed: and in some cases what he called aromatic turned out not to contain what we today recognise the word to imply. Mike Turnbull (talk) 13:51, 10 November 2022 (UTC)
- Oh, it has its origin in that way. It has no current such meaning. The fact that something meant something in the past has no bearing on what it means in the present. See Etymological fallacy. When an organic chemist uses the term "aromatic" in the context of ring compounds with delocalized pi systems, they are not saying anything about their scent. --Jayron32 15:08, 10 November 2022 (UTC)
- The word "aromatic" does have its origin in the odor of such compounds. See Aromaticity#The term "aromatic". It was used in that sense by August Wilhelm von Hofmann in 1855, before the relevant structures were confirmed: and in some cases what he called aromatic turned out not to contain what we today recognise the word to imply. Mike Turnbull (talk) 13:51, 10 November 2022 (UTC)
- To appreciate the importance of the benzene ring you should consider somewhat similar compound - cyclohexane. In both six carbon atoms make a ring but their properties are very different. Ruslik_Zero 19:19, 10 November 2022 (UTC)
- Wow, what a lot of clear, helpful answers! I'm now much more aware of its importance, and why; and lots more to be reading. Thanks all for your expertise. MinorProphet (talk) 23:35, 10 November 2022 (UTC)
Jeez, this is wonderfully complex... It was finding File:Benzene-resonance-structures.svg which allowed me to conceptually grasp (I think) the dual quantum states of benzene and how the ring model is a sort of approximation of the states; and how quantum chemistry can explain it.
Having read and attempted to comprehend the articles recommended above, I've got a load more questions. Some of them may be plain wrong, but I would be grateful for any further straightforward answers.
- How does the benzine resonance diagram above relate (if at all) to File:StationaryStatesAnimation.gif and the Schrödinger equation?
- Which type of molecular orbital does benzene have?
- Do all ring structures have delocalised electrons?
- What importance does molecular symmetry have in forming pi bonds in benzene?
- Is it only pi bonds that have de-localised electrons?
- What effect do the conformations of cyclohexane have in the real world? Do other compounds exhibit this behaviour?
- @MinorProphet: These are the sorts of questions that chemists on graduate courses need about a year of study to master! Try reading Woodward–Hoffmann rules next, which covers many of these topics but does get quite difficult to follow without the sort of background best found by reading a decent organic chemistry textbook. Mike Turnbull (talk) 18:11, 13 November 2022 (UTC)
- To answer a few of these good questions, benzene has both sigma and pi molecular orbitals. As one approximation, the sigmas represent the "first" bond along each edge and are "in the plane" (in-line between the atomic nuclei), whereas the pi are the additional bonding electrons "above and below the plane"; overall, it's two halves of a bagel (pi) with an onion-ring (nuclei and sigma) as the sandwich filling. File:Benzene MO diagram.png illustrates how the p atomic orbitals of the carbon atoms align and combine in various ways to form the pi molecular orbitals.The aromaticity is a pi phenomenon here, and resonance/delocalization in general is usually a pi and rarely a sigma situation. It's the alignment of more than two atomic orbitals that allows delocalization, not the molecular shape (ring) itself: allyl cation has delocalized electrons but cyclohexane does not. Aromaticity is a more complex situation that relates to delocalization that is around a ring: benzene has it, but cyclohexa-1,3-diene has delocalization but not aromaticity and cyclohexa-1,4-diene does not even have delocalization.Conformations of cyclohexane are just one notable application of the ideas of conformational analysis, where pairs of bonded atoms can rotate relative to each other, leading to more- or less-stable geometries in those parts of the structure. Many biological functions are dependent upon molecular shape (the lock and key model, for example), so the ways a molecule can be shaped at all (flexibility) and their relative stability in different shapes are both important when structures interact with each other. DMacks (talk) 19:44, 13 November 2022 (UTC)
- Thanks all for your great comments and explanations. Reading the above links makes me realise how much I would have liked to have understood the maths in order to study this sort of thing at uni. It makes so much sense of what I formerly had a mere vague grasp of. I did actually buy a 2nd-hand c. 1960s organic chemistry textbook after some interesting experiences with psilocybin, but again the maths and algebra defeated me. Ah well, it's been satisfying in other ways, less concerned with the scientific method and the essential matter of the universe.
- So, although I have probably reached the limits of my understanding beyond these clear explanations, it's been very enlightening finding out how far I could get. Wouldn't it be possible to gather all the above info into a sub-section of benzene, headed
==Importance/significance of benzene==
? - So, as a final unanswered question from above, please: How does the File:Benzene-resonance-structures.svg diagram relate (if at all) to File:StationaryStatesAnimation.gif and the Schrödinger equation? Many thanks, MinorProphet (talk) 17:48, 14 November 2022 (UTC)
- The answer to that question is "not really at all". What we call "resonance structures" is an artifact of Lewis diagrams as a model, and does not represent anything all that profound about molecules. Molecules are just collections of nuclei and electrons arranged in a relatively stable geometry. When you think of a single atom, you can envision a nucleus at the center of an electron cloud, that represents the sort of "average" of all of the quantum states of the electrons spread out over the space around the nucleus. A molecule is similar, in that case you have multiple nuclei floating in a more complex-shaped electron cloud, the geometry of which is controlled by the geometry of molecular orbitals. Lewis diagrams are useful for simple molecules that feature simple bonding, where "bonds" of two electrons each are represented by lines. However, the molecular electron cloud is more complex than this; what a line represents is not a rigid, stationary pair of electrons staying still between the atoms, but rather represents about 2 electrons worth of negative charge acting to hold the respective nuclei together; given that electrons are essentially not standing still in that space, that 2-electrons-worth-of-charge is an average of all of the motions of those electrons (ish... it's a bit messier than that, but it works well enough for this explanation). Since it's just an average anyways, there's nothing that says it has to be exactly 2 (or a multiple of 2) electrons. You can have 1 electron's worth of charge, or even a fraction of an electrons worth of charge holding the nuclei together in a molecule. There is nothing wrong with that from a physics point of view. The problem is that Lewis diagrams are a rather blunt tool. How do you represent a bond consisting of 3 electrons worth of charge with them? What about 2.67 electrons worth of charge? I mean, all I have are dots and lines to do that. What we call "resonance structures" are just a kludge to make Lewis diagrams work with more complex electronic situations. Simply put: resonances doesn't necessarily represent anything profound about molecules; which are happily doing their own thing with no particular problems; they're just a way so that our diagrams and models can "fit" what is actually going on. One of the impetuses of molecular orbital theory was to abandon the overly simplistic Lewis theory and develop a more robust model; the model often lacked a nice little picture we can write with letters and lines, but in abandoning that we developed a more predictive and robust model of molecules. We still use Lewis diagrams today because they are convenient, but they kind of fall apart when we get to anything beyond simple 2-electron bonds. --Jayron32 13:33, 15 November 2022 (UTC)
@Jayron32: Your explanations seem so clear and free of jargon, thank you. I think I get the idea. The more you know, the deeper it gets... I wonder if you (or someone) could please answer some tangential questions: <What, more?>
- What are the solid black thin triangular pointers in eg Arrow pushing#E1 eliminations?
- If people are still talking about valences as a valid way of understanding atomic theory, how much of all this theory on bonds might Kekulé, working on Edward Frankland's idea, have actually understood?
- What needed to happen to mathematics/physics between Kekulé's 1865 paper and, say, Einstein's of 1905, to to come up with quantum chemistry? How far is Aleph null, my favourite infinity, involved?
- Who came up with the concept of bond lengths and angles between bonds?
I'm very grateful for everyone's interest and expertise in explaining unbelievably complex ideas in straightforward terms. MinorProphet (talk) 16:04, 15 November 2022 (UTC)
- Sure thing! Glad to be of service! Let me do my best.
- For the triangular bits, see skeletal formula for more details. In organic chemistry, a highly condensed form of Lewis diagrams is shown, omitting carbons and hydrogens from drawings. In an organic skeletal formula, each end or vertex is considered to be a carbon atom (plus enough H atoms to give it 4 bonds). In order to represent three dimensions on the page, we use the "wedge and dash" method. Any bond that comes "towards" the viewer ("out of the page") is written as a wedge (what you call "solid black thin triangular pointers") and any bond going "away" from the viewer ("into the page") is written as a series of dashes. See also here for more details.
- August Kekulé was really on the "tip of the spear" for developing what we know more formally call valence bond theory, which Gilbert N. Lewis put together in his landmark textbook on the subject in 1916, but Lewis didn't really invent it out of whole cloth; these ideas had been kicking around Chemistry for decades and decades, it really can't be credited to any one person, August Kekulé both developed some of the early ideas on valence and also expanded on ideas developed earlier. Really, valence can be traced all the way back to things like the Law of definite proportions and the Law of multiple proportions and now we're getting back to Proust, Dalton, and Lavoisier; back to the real founding fathers of Chemistry. The notion of valence had already existed when fellow Russian Dmitri Mendeleev incorporated it into his periodic law, working concurrently with Kekulé. Valence (chemistry) discusses some of this in the "Historical development" section.
- So, the thing about Einstein is (and I am NOT saying this to diminish him, he's really deserving of all the credit he gets!), is that he's just got a better PR machine than other equally (and in some fields more) important scientists working at the time. Einstein's contributions to quantum theory are really limited; in his "Annus Mirabilis" papers of 1905, it was his application of quantum theory to the photoelectric effect. In terms of other contributions, it was mostly that he was a pretty good foil in trying to poke holes in quantum theory (his famous "God does not play dice" criticism of QM for example, and the EPR Paradox as another), except as far as we can tell, he was usually wrong in his feelings about quantum mechanics. If we really want to trace QM from its roots, it starts with Max Planck, who invented QM as a literal mathematical kludge to fix the ultraviolet catastrophe, a deviation from experiment caused by the Rayleigh–Jeans law in trying to predict the results of blackbody radiation. I don't even think that Planck himself at first believed it was true, he merely created it as a mathematical tool to help fix the problem. From a chemist's point of view, the real genesis of QM in chemistry starts with the Bohr model of the atom developed by Neils Bohr (building on the Rydberg formula and several earlier models explained in the intro to the Bohr model article). Modern quantum theory really starts with Erwin Schrödinger and the application of wave dynamics to quantum theory; the article Old quantum theory will answer your question of how we got there from it's earliest beginnings.
- I'm not sure what you mean "came up with". They are actually experimentally measurable things. Frequently, things like bond lengths and angles can be obtained via a process known as X-ray crystallography, so if we want to blame anyone for how we came up with this knowledge, it was the two Williams Bragg, the father-son team that came up with Bragg's law, which allows us to extract crystal shapes (and thus bond lengths and bond angles) from the scattering of X-rays off of solid crystals. Later techniques such as Raman spectroscopy and Gas electron diffraction have been used, among many others. In terms of predicting bond angles and lengths, that comes down to VSEPR theory, which provided the predictions that experimental techniques either confirmed or refined. So, if we have to blame anyone specific for first developing notions of bond length and bond angles and the like, it would be Ronald Gillespie and Ronald Sydney Nyholm for developing VSEPR theory, and William Henry Bragg and William Lawrence Bragg for Bragg's law and X-ray crystallography. And the experimental techniques predated the theoretical by some decades. --Jayron32 16:42, 15 November 2022 (UTC)
- I think your description of K as being "on the tip of the spear" is entirely appropriate. It's a pity that WP articles tend to shy away from assigning extraordinary greatness to individuals - there appears to be little to choose between the biography of, say, an Estonian footballer and eg Lavoisier (whose portrait appears at the head of Annales de chimie - Ext. links section partly mea culpa). The exquisite fertility of the minds of the founders of chemistry appears to confound our petty existences - most of us can only follow in their wake and murmur, "Yes, boss." Even more inviting reading material - many thanks once again. MinorProphet (talk) 21:13, 15 November 2022 (UTC)
November 11
Rose smell
I understand some roses do not have a sweet smell like they used to. Why? I thought all roses had a sweet smell.--Christie the puppy lover (talk) 19:01, 11 November 2022 (UTC)
- This is not exactly new, but breeders have often sacrificed odor for other traits, particularly shelf life, when breeding commercial roses. Also, there are rose species, such as Rosa agrestis (field briar) that have hardly any odor. Abductive (reasoning) 19:12, 11 November 2022 (UTC)
- "Historically all roses had an odour, but after the introduction of almost scentless China Rose and the larger Tea Rose, both from China in the 19th-century smell was slowly bred out from some roses". [1] Alansplodge (talk) 19:15, 11 November 2022 (UTC)
- There are many true rose species and many cultivars grown as garden roses or to be used as cut flowers. Many of these varieties are bred primarily for their looks, often by drastic inbreeding, while not selecting for smell – and natural selection is sidelined. So it is no wonder that some cultivars lost the captivating smell of their wild ancestors. Tomatoes are now largely selected for good looks (a smooth shiny skin) and long shelf life; the effect is that they have become much less tasty. --Lambiam 19:28, 11 November 2022 (UTC)
- Right, and expanding on that a bit; odor and flavor are meant to attract pollinators and animals to eat the fruit and spread the seeds, and so natural selection tends to favor a period of the most intense odor and flavor to coincide with peak fertility and ripeness. If you breed just for longer periods of freshness, you necessarily have to spread the same amount of aromatic chemicals over a longer time period. Abductive (reasoning) 19:59, 11 November 2022 (UTC)
- Thanks all - great answers. Now I get it.--Christie the puppy lover (talk) 21:04, 11 November 2022 (UTC)
- But do you?
- Right, and expanding on that a bit; odor and flavor are meant to attract pollinators and animals to eat the fruit and spread the seeds, and so natural selection tends to favor a period of the most intense odor and flavor to coincide with peak fertility and ripeness. If you breed just for longer periods of freshness, you necessarily have to spread the same amount of aromatic chemicals over a longer time period. Abductive (reasoning) 19:59, 11 November 2022 (UTC)
Vitae Summa Brevis Spem Nos Vetat Incohare Longam
They are not long, the weeping and the laughter,
Love and desire and hate:
I think they have no portion in us after
We pass the gate.
They are not long, the days of wine and roses:
Out of a misty dream
Our path emerges for a while, then closes
Within a dream.
Ernest Dowson
MinorProphet (talk) 22:39, 15 November 2022 (UTC)
Foo in observable universe
At what rate, if any, estimates like the number of foo in observable universe become obsolete due to universe's expansion? I understand that large numbers like 200 sextillions of estimated stars likely wouldn't considerably change over years, but does universe expand fast enough to make such estimates, including Eddington number after 82 years, dated (warranting placing, say, year or century of estimate)? 212.180.235.46 (talk) 21:33, 11 November 2022 (UTC)
- On cosmological timescales, 82 years is completely insignificant, so a 1930s estimate of the number of protons in the observable universe would still be a reasonable estimate today.
- Over much longer time periods, the observable universe will indeed change due to expansion of the universe. First, over the next few billion years, light from some more distant objects than have been observed will reach us, having not yet had enough time to do so, causing an increase in the size of the observable universe and thus raising the Eddington number. However, because the expansion of the universe is accelerating, everything not gravitationally bound to the Local Group will eventually recede beyond the cosmological horizon, on the order of 1011 to 1012 years from now (when the universe reaches 100 times its current age). In this case, one could say the mass of the observable universe is approximately the mass of Milkomeda, which is far less than the mass of the observable universe today. Of course, these estimates assume several conservation laws are upheld – mainly mass–energy; it is possible that particles are "lost" by collisions and conversion to energy, but the total mass–energy is unchanged – and does not consider the possibility of proton decay, both of which might alter the number of protons in the universe on even longer timescales (around 1034 years for proton decay if it occurs).
- In any case, humanity won't be around long enough for a perceptible change in these estimates to occur. Complex/Rational 05:05, 12 November 2022 (UTC)
- While (in our best scientific understanding) such physical values themselves are constant or change only extremely slowly, slower than anything we might detect by direct measurement, our estimates for such values may change rapidly. In 1929, when Edwin Hubble published his redshift observations, including his estimate of what is now known as the Hubble constant, the age of the universe, based on the estimated value of this parameter, was thought to be about 1.8 billion years. By 1952, revised estimates of the Hubble constant had increased the estimated age of the universe to about 3.6 billion years.[2] The currently accepted best estimate (as of 2018) is about 13.8 billion years. One might be tempted to define a meta-Hubble constant for the speed of growth of the estimated age (observed to have been about 135 million years per year). --Lambiam 08:53, 12 November 2022 (UTC)
November 12
Can 2 people eat the same food but 1 gets diarrhea, the other does not?
I know I asked this question before, but this time want to expand on it. I've heard people who know people who travel from a modern city to a 3rd world country, they often get diarrhea due to not getting used to the food. But then, what about the other way around? How about 2 people travel to a new country together, can 1 get diarrhea and the other does not? Or, where they both get diarrhea, but 1 quickly gets immune to the food, the other does not? And let's take out consideration such as lactose intolerance, diabetes, food allergies, etc. Thanks. 67.165.185.178 (talk) 01:36, 12 November 2022 (UTC).
- Gut microbiota. Abductive (reasoning) 04:43, 12 November 2022 (UTC)
- Travelers' diarrhea. 136.56.52.157 (talk) 05:24, 12 November 2022 (UTC)
- To add to the earlier responses, yes, it is entirely possible. Different people may react differently in response to a new nutritional environment; this is in fact quite common. "Getting immune" is not the best way to name the relatively rapid adaptation to a new environment, which often does not involve the immune system. Rather, the gut microbiota, more commonly referred to as intestinal flora, needs to achieve a new balance. --Lambiam 07:11, 12 November 2022 (UTC)
Are mushroom considered fruit or vegetable?
Despite it being a fungus. Can it be considered a vegetable, nutrition-wise? Also, what other common fungi do we eat, besides mushrooms? Thanks. 67.165.185.178 (talk) 02:36, 12 November 2022 (UTC).
- It doesn't meet the botanical definition of either "fruit" or "vegetable" (though some of them have fruiting bodies). It's a vegetable in a culinary sense, though, similar to the way tomatoes are not a fruit, and clams are fish, in a culinary sense. --Trovatore (talk) 02:40, 12 November 2022 (UTC)
- Truffles are fungi. 136.56.52.157 (talk) 05:34, 12 November 2022 (UTC)
- Do they all taste bad or just some of them? I expected truffle-flavored popcorn the fine wine or caviar of fungi to taste.. better than eating 7 grams of dry yeast to see if juice on an empty stomach can ferment. Sagittarian Milky Way (talk) 14:23, 12 November 2022 (UTC)
- They are all considered to taste very good (if stored and prepared correctly). If you have eaten actual truffles that tasted bad to you, then either they were not real truffles, or there was something wrong with them, or you are unusual in not liking a taste that most others do. The last is entirely possible, as genetic differences as well as lack of familiarity can greatly affect how tastes are perceived. I, for example, absolutely loathe licorice and aniseed, and somewhat dislike celery, though the majority (I am told) like them.
- The taste of truffles is notoriously difficult to reproduce (which is why truffles themselves are so expensive). I doubt that "truffle-flavoured popcorn" would taste anything like real truffles. {The poster formerly known as 87.81.230.195} 5.64.163.219 (talk) 17:00, 12 November 2022 (UTC)
- The bag looked old. Could be spoiling? Sagittarian Milky Way (talk) 17:32, 12 November 2022 (UTC)
- Do they all taste bad or just some of them? I expected truffle-flavored popcorn the fine wine or caviar of fungi to taste.. better than eating 7 grams of dry yeast to see if juice on an empty stomach can ferment. Sagittarian Milky Way (talk) 14:23, 12 November 2022 (UTC)
- Vegetables and other plant sources of food are typically rich sources of vitamin C, which is absent in mushrooms (which are a rich source of B vitamins, though). When it comes to nutrition, strict fungitarians may need to resort to vitamin supplements to prevent scurvy. --Lambiam 06:55, 12 November 2022 (UTC)
- Besides having very few calories; a diet of fungi would lead to starvation long before scurvy would be an issue. Alansplodge (talk) 14:04, 13 November 2022 (UTC)
- Unless you eat 8 kg of mushrooms per day. --Lambiam 19:42, 13 November 2022 (UTC)
- Besides having very few calories; a diet of fungi would lead to starvation long before scurvy would be an issue. Alansplodge (talk) 14:04, 13 November 2022 (UTC)
Quorn™ is largely fungal- protien-based.
Which domesticated animal has the heaviest cranium relative to the rest of its skeleton?
Out of all fully domesticated animals, which species has the heaviest cranium (excluding the teeth and mandible) compared to the mass of the entire skeleton (including all mineralized tissues)? Quick Trundleteacher (Talk) (Inputs) 17:07, 12 November 2022 (UTC)
November 13
Fine-structure constant as a reciprocal
It is customary to present the value of the fine-structure constant as a reciprocal, as in
Do we know the historical origin of this custom? Is it due to Eddington's numerological obsession, or were estimates of its value already customary presented this way in 1928 when Eddington published the first version of his curious theory that must be the reciprocal of a whole number? Is there another reason than tradition to keep presenting it this way? --Lambiam 07:17, 13 November 2022 (UTC)
- See Fine-structure_constant#Numerological_explanations_and_multiverse_theory. Historically the fine structure constant was believed to be precisely 1/137 so quoting it as a decimal would reduce the precision.Polyamorph (talk) 08:13, 13 November 2022 (UTC)
- The section does not reveal that Eddington first pronounced that exactly, before being forced in the face of more precise measurements to revise this to again exactly, leading to the satirical magazine Punch calling him "Sir Arthur Adding-One". But was Eddington indeed the first to present the value in the form ? And since his theory obviously does not hold water, why hold on to this strange convention? --Lambiam 12:00, 13 November 2022 (UTC)
- I'd just be speculating, but it does seem to me that 1/α is just as natural a quantity as α itself, and it's probably more intuitive for people to remember 1/α as "about 137" than to remember α as "about 0.0073", if for no other reason than you don't have to count zeroes. --Trovatore (talk) 19:30, 13 November 2022 (UTC)
- If people will tolerate an anecdote — I was in Fleming Hovse; our rivals were Page House, whose denizens were called Page Boys. Being Caltech students, of course all of us were nerds by any reasonable standard, but the Fleming culture required that we avoid seeming like it. It was not cool to study ("snake") too much, or to show off one's knowledge ("blaze"); infractions would result in you being forcibly placed in the shower with your clothes on and the water turned on ("being washed").
- Someone had started a tradition of waiting till 3:14 AM and yelling across the courtyard, "snake, Page Boys, it's pi o'clock!".
- One time I waited till 1:37 and yelled "snake, Page Boys, it's 1/α o'clock!"
- Yes, I did get washed. But it was with appreciation. --Trovatore (talk) 20:03, 13 November 2022 (UTC)
- Most likely because it's an easy to remember ratio, similar to pi, which is also a ratio (approximately 3:1, 3.14:1, ... ad infinitum). Specifically, it's the ratio of the velocity of the electron in the first circular orbit of the Bohr model of the atom to the speed of light in vacuum; or . Modocc (talk) 19:54, 13 November 2022 (UTC)
- I'd just be speculating, but it does seem to me that 1/α is just as natural a quantity as α itself, and it's probably more intuitive for people to remember 1/α as "about 137" than to remember α as "about 0.0073", if for no other reason than you don't have to count zeroes. --Trovatore (talk) 19:30, 13 November 2022 (UTC)
- The section does not reveal that Eddington first pronounced that exactly, before being forced in the face of more precise measurements to revise this to again exactly, leading to the satirical magazine Punch calling him "Sir Arthur Adding-One". But was Eddington indeed the first to present the value in the form ? And since his theory obviously does not hold water, why hold on to this strange convention? --Lambiam 12:00, 13 November 2022 (UTC)
- Not really an answer, but see "Why Is 1/137 One of the Greatest Unsolved Problems In Physics?" PBS Space Time youtube. Johnuniq (talk) 00:50, 15 November 2022 (UTC)
Which animal species is the most energy efficient?
By efficiency, I mean how much of the energy consumed is converted into useful work. IIRC, humans are only 25% efficient in that regard. Also, if there is an article on here providing the information, please say so. StellarHalo (talk) 09:45, 13 November 2022 (UTC)
- Something like feed conversion ratio? You can rest assured that we have not checked all animal species for this. (By the way, "controlling for body size, primates burn about 50 percent fewer calories than other animals", and humans eat way fewer calories than chimps.) Abductive (reasoning) 11:06, 13 November 2022 (UTC)
- And how much of the energy consumed is converted into useless work? For humans perhaps more than 25% --Lambiam 12:03, 13 November 2022 (UTC)
- Define "useful work". Everything the metabolism does serves a purpose Cambalachero (talk) 13:48, 13 November 2022 (UTC)
- The metabolism converts energy packed in nutrition to energy stored in the body. While the conversion efficiency is not 100%, the loss is not work in the sense of physics. --Lambiam 17:50, 13 November 2022 (UTC)
- The ratio depends on whether someone does useful work. A pencil pusher hardly needs to produce work in the physics sense, so the percentage will be much lower than for a person performing full days of heavy manual work. It also depends on whether you only consider work output that is paid for, or work that is necessary to be able to work, such as getting to and from work. Our article Human power states: "Over an 8-hour work shift, an average, healthy, well-fed and motivated manual laborer may sustain an output of around 75 watts of power." That amounts to 0.6 kWh, or about 1,000 kJ per day.
- The recommended daily intake for a male adult with a desk job is about 10,000 kJ, that for a manual worker more like 14,000 kJ. That suggests that about 4,000 kJ nutritional intake is converted to some 1,000 kJ of work output. If you consider only this, you get a ratio of 25%. But there is also the other 10,000 kJ, which goes mostly to basal metabolism, to maintain homeostasis. So taking all into consideration, some 14,000 kJ of intake produces 1,000 kJ of (paid) work. If you include unpaid but necessary work, the latter number goes up by an estimated 200 kJ per day, giving a conversion efficiency of about 9%.
- By using other definitions of "useful" work you can probably get wildly different answers than given by this back-of-the-envelope calculation. --Lambiam 18:53, 13 November 2022 (UTC)
- The size of the animal is also important. The internal activity the body uses just to stay alive is much higher in small animals than in big ones. Humans are not as big as elephants or whales, but overall they are closer to the big animals than to the small ones. Check this video Cambalachero (talk) 23:04, 13 November 2022 (UTC)
Extension cord
I have an old German extension cord that has "10-16/250" written in one of the sockets. I'm guessing 250 means 250 V. Does 10-16 stand for amperes? Wondering if I can plug in a 2000 W radiator in it. 31.217.13.249 (talk) 14:12, 13 November 2022 (UTC)
- Did you try calling an electrician? ←Baseball Bugs What's up, Doc? carrots→ 15:36, 13 November 2022 (UTC)
- The same question has been posed on many websites. The consensus among responders is that the values 10–16 refer to amperes and the 250 to voltage. The opinions differ on the meaning of 10A–16A. One theory is that 10A is the maximal current for DC and 16A for AC. Another theory is that 10A is the maximal continuous load, while 16A is for shorter use. In either case, it should be safe for up to 2500W. You can check by hand now and then whether the socket or plug heats up to an uncomfortable temperature during an extended period of use. If they are still fine after fifteen minutes, you may assume that they won't get much hotter. --Lambiam 17:06, 13 November 2022 (UTC)
- Thanks! 31.217.50.28 (talk) 19:44, 13 November 2022 (UTC)
- One clarification: We are talking about electricity at European voltage of around 230 V, right? Otherwise the plugs would presumably be wrong. But a 2000 W appliance on North America's 120 V would require about 16 A, so I thought I should confirm that that's not what you want. --174.89.144.126 (talk) 04:41, 14 November 2022 (UTC)
- Do not rely on a "hot-touch-test" to determine if a wire is safe to use. Such a test will tell you more about the thermal properties of the insulation casing than about the temperature. (Here’s a semi-famous video of someone holding a hot-enough-to-be-glowing-yellow piece of insulating material with bare hands.) Furthermore, if the wire was in fact hot enough to get damaged, there is a risk of shock. Lambiam, that was not good advice. TigraanClick here for my talk page ("private" contact) 10:30, 16 November 2022 (UTC)
- Assuming a 230V supply voltage (the standard in most of the EU, including Croatia), a 2000W appliance implies a current of 8.7A and a 2500W appliance a current of 10.9A. Generally, the specs of extension cords are well below 90% of what is actually safe. Even without safety margin, the time before a wire carrying a current below 110% of what is safe gets so hot as to potentially cause skin burns is considerable; if it can radiate some heat it may never get there. The advice was to apply the test for hotness occasionally up to 15 minutes after making the connection. Moreover, the advice was not to touch a wire, but a (less thermally compromised) socket or plug, such as one commonly would touch anyway when breaking the connection. --Lambiam 12:10, 16 November 2022 (UTC)
- Thanks! 31.217.50.28 (talk) 19:44, 13 November 2022 (UTC)
- A medium-duty extension cord might be rated for 10 amps with 16AWG wire. Amperage ratings vary with wire size and cord length(s), and for various reasons manufacturers of space heaters warn against using extension cords. Modocc (talk) 18:36, 13 November 2022 (UTC)
- "an old German extension cord" may indicate that the AWG system (American Wire Gauge) might not have been the standard used to make this cord. Also, even though 10A through that extension cord might be safe, the longer the extension cord, the more losses you have within it. Perhaps it's irrelevant for a heater, but some appliances will run less efficiently at a lower voltage. Dhrm77 (talk) 21:08, 14 November 2022 (UTC)
- I typed the search string
"10/16 250"
in an online search and the first (and almost only) result was a manufacturer’s website. The technical datasheet saysThermal current: 10/16 A
. So it’s definitely a current rating, but why there are two ratings I could not find out for sure even with the additional keyword of "thermal current". I suspect it’s a German standard thing but I do not have the linguistic ability to search for more.
- Possibilities include:
- As written above: continuous vs. peak use. For instance things like motors can draw a large amount of current for one second or so during startup.
- Similar but slightly different: during unplugging vs. during use: you can draw power through the cable at some high current but you must decrease the current to safely unplug.
- A power factor thing to correct for inductive load issues (but then it’s not clear to me why they chose a 10/16 = 62.5% power factor reference; the power factor can vary a lot depending on the appliance etc.).
- TigraanClick here for my talk page ("private" contact) 10:30, 16 November 2022 (UTC)
- The numbers seem to refer primarily to the plugs/sockets of the Schuko type. The German article has links to the relevant DIN
normsstandards (refs 16 and 17). While thenormsstandards themselves have to be paid for, the title indicates that 10A is indeed for DC and 16A for AC. --Wrongfilter (talk) 11:24, 16 November 2022 (UTC)
Vaccines and autism: My autistic family
When I got my 18-month-old vaccine, I stopped talking until I was almost four. My tests reveal that I have a 79% chance of autism. And my mom's Godmother said that she behaved very similarly after hers. And hers was always not liking people and being extremely introverted. And her tests revealed that she has an 89% chance of autism. If vaccines don't cause autism, why did my family act suddenly autistic after their vaccines? 67.215.28.226 (talk) 16:47, 13 November 2022 (UTC)
- See notes at top of page:
We don't answer (and may remove) questions that require medical diagnosis or legal advice.
We don't answer requests for opinions, predictions or debate.
- The causes of autism are to an extent unclear: there is clearly a hereditary element, but environmental factors may also come into play. Evidence that vaccination is one such factor is however lacking, despite the repeated claims to the contrary. Anecdotes about individuals don't prove anything. Science is based on data. AndyTheGrump (talk)
- You might also find the article correlation does not imply causation interesting. Writ Keeper ⚇♔ 18:14, 13 November 2022 (UTC)
Then why did I suddenly stop talking almost immediately after I got my shot? It's 100% true! 67.215.28.226 (talk) 18:27, 13 November 2022 (UTC)
- See Writ Keeper's reply. – dudhhr talk contribs (he/they) 18:38, 13 November 2022 (UTC)
- You might need to clarify that statement. I have met someone who spent most of his childhood not talking, by choice. In your case, was it a choice? Or an inability to talk? Or was it a sense that you didn't need to say anything? Or were you in some kind of vegetative state? How do you recall that period? (not that I would be able to explain why, but I'm curious about the reasons too, and clarifying might help.) Dhrm77 (talk) 20:43, 14 November 2022 (UTC)
Awesome. Thanks. 67.215.28.226 (talk) 18:46, 13 November 2022 (UTC)
- The median age of onset of speech loss in what is called autistic regression has been reported to be 18 months.[3] That means that for about half of the infants undergoing this, it happens before they reach 18 months, and for about the other half when they have reached that age or later. Obviously, if children undergo some procedure when they are 18 months, among those experiencing speech loss this will occur for about half after that procedure, possibly shortly after – irrespective of the nature of the procedure. --Lambiam 19:19, 13 November 2022 (UTC)
- It's tragic, really, that people want to find a reason, other than bad luck, for their children's autism, and that unscrupulous shysters will tell them it's vaccines or overhead electric lines in order to part them from their money. Abductive (reasoning) 19:38, 13 November 2022 (UTC)
- We can probably think of a few celebrities who've fallen for that scam. Meanwhile, I'm reminded of an old story about a child who wouldn't talk. One day at mealtime, the kid suddenly said, "Pass the salt, please." The surprised parents asked him what took him so long to start talking. He said, "Well, until now, everything was OK!" ←Baseball Bugs What's up, Doc? carrots→ 23:19, 13 November 2022 (UTC)
- That's the eponymous origin of the name Einstein syndrome. DMacks (talk) 00:57, 14 November 2022 (UTC)
- We can probably think of a few celebrities who've fallen for that scam. Meanwhile, I'm reminded of an old story about a child who wouldn't talk. One day at mealtime, the kid suddenly said, "Pass the salt, please." The surprised parents asked him what took him so long to start talking. He said, "Well, until now, everything was OK!" ←Baseball Bugs What's up, Doc? carrots→ 23:19, 13 November 2022 (UTC)
- It's tragic, really, that people want to find a reason, other than bad luck, for their children's autism, and that unscrupulous shysters will tell them it's vaccines or overhead electric lines in order to part them from their money. Abductive (reasoning) 19:38, 13 November 2022 (UTC)
- Very soon after receiving my polio shot outside in the schoolyard back in the 1950s (it was a nice sunny day), I broke my collarbone in that very same schoolyard. Therefore vaccines cause collarbones to break. And The Lack of Pirates Is Causing Global Warming. HiLo48 (talk) 02:08, 14 November 2022 (UTC)
- Have those Somali pirates been goofing off again? Aaaarrrrrggggghhhh! Clarityfiend (talk) 06:17, 14 November 2022 (UTC)
- The relevant Wikipedia article might be the Lancet MMR autism fraud. Alansplodge (talk) 18:31, 14 November 2022 (UTC)
- As well as MMR vaccine and autism. --CiaPan (talk) 07:21, 15 November 2022 (UTC)
bug ID
hello. what is this? worm/caterpillar/fly larva? https://postimg.cc/gallery/NHbMtw8 Northern Central Europe. Thank you everyone in advance. Aecho6Ee (talk) 17:28, 13 November 2022 (UTC)
November 14
How to use natural gas on appliances designed only with propane burners ?
Hello, given identical pipes, and given in Europe Propane is distributed at 34millibars and 20millibars for main gas.
Using the Wobbe index, how much natural gas should be compressed in order to reach the level of propane at standard pressure ? 2A01:E0A:401:A7C0:DD84:4D2F:2DD3:58D4 (talk) 00:05, 14 November 2022 (UTC)
- You should consult an expert to see if it's possible, and to hedge your bets you should get some life insurance for yourself. ←Baseball Bugs What's up, Doc? carrots→ 02:34, 14 November 2022 (UTC)
- This is for requesting a new device from a professional which will pass certification. Not crafting something myself.
- But as this is outside the country, I need to give the relevant specs. 2A01:E0A:401:A7C0:DD84:4D2F:2DD3:58D4 (talk) 11:38, 14 November 2022 (UTC)
- The composition of natural gas differs depending on the source and how it has been processed. The caloric value of Swedish natural gas is substantially higher than that of natural gas from the Netherlands. Compression may not be a good idea: a huge compression is required, resulting in a pressure for which the existing pipes are not graded, domestic appliances are designed for a standard overpressure, and if the gas delivery service uses pressure regulators at the service entrances (see Natural gas § Domestic use), the effect of compression will be undone anyway. --Lambiam 07:04, 14 November 2022 (UTC)
- The underlying issue is portable natural gas stove for cooking (The kitchen can’t be modified) with multiple gas burners as well as forced‑air gas heaters seems to only exists for propane. Propane with bottles is sold 40% higher than main gas in France.
- Otherwise, the aim in terms of standard is using G20 to G31. The Netherlands in reality use ʟᴘɢ as main gas if I understand correctly. 2A01:E0A:401:A7C0:DD84:4D2F:2DD3:58D4 (talk) 11:36, 14 November 2022 (UTC)
- Actually, the Netherlands use methane, but impure, as it contains about 14% nitrogen by volume. It comes out of the Groningen gas field that way. That's a single gas field, big enough to provide practically all domestic gas in the Netherlands throughout the natural gas age (1963–2023), so it's of very uniform quality. Making burners optimised for this impure gas was much simpler than removing the nitrogen. I assume the Swedish gas has less nitrogen and maybe more ethane and propane.
- BTW, more or less portable natural gas stoves with 3–4 burners have been around, but I haven't seen one since the end of last century. And you'd need one optimised for the gas coming out of your pipes. PiusImpavidus (talk) 17:13, 14 November 2022 (UTC)
- As you know natural gas in France mostly come from ʟɴɢ from Algeria before the Russian war… The Shift to ʟɴɢ from the United States for replacing Russian gas didn’t require changing equipment, hence the reason I assumed G20 was equal. Or maybe the Netherlands don’t conform to G20… 2A01:E0A:401:A7C0:4914:DFDB:AF86:8F9D (talk) 22:29, 14 November 2022 (UTC)
- Dutch natural gas is delivered at G25. Delivery is slated to terminate in 2030. --Lambiam 08:26, 15 November 2022 (UTC)
- On my side, there are plans to mostly shut down the central heating of the building I’m living instead of investing in more efficient way of heating. Electricity per apartment is caped at 12Kw while it takes 15Kw to 20Kw per home to heat those apartments without any isolation. So this requires forced‑air gas heaters at least for some years, but all of those I found are working only with ʟᴘɢ or Propane : a converter is needed and some companies agrees to build 1 : but I need to give the design details. Since paying a subscription to natural gas is required, I’m planning to switch to gas stoves for cooking. 2A01:E0A:401:A7C0:FD73:3340:23D9:8642 (talk) 02:28, 16 November 2022 (UTC)
- Dutch natural gas is delivered at G25. Delivery is slated to terminate in 2030. --Lambiam 08:26, 15 November 2022 (UTC)
- As you know natural gas in France mostly come from ʟɴɢ from Algeria before the Russian war… The Shift to ʟɴɢ from the United States for replacing Russian gas didn’t require changing equipment, hence the reason I assumed G20 was equal. Or maybe the Netherlands don’t conform to G20… 2A01:E0A:401:A7C0:4914:DFDB:AF86:8F9D (talk) 22:29, 14 November 2022 (UTC)
How many combinations in garage door remote and TV remote controls?
I heard for garage door remote controls the number is in the order of a 4-digit number? What about for TV remote controls? Do they have an overlap spectrum, so a TV remote can work on someone else's garage door? And vice versa. And I'd make this discussion International. 67.165.185.178 (talk) 06:24, 14 November 2022 (UTC).
- There will be 10000 combinations of 4 digits 0-9. TV remotes usually uses near infrared, whereas a garage door remote will be a HF, VHF or UHF radio transmission. So the answer to your last question will be "no". Graeme Bartlett (talk) 06:53, 14 November 2022 (UTC)
- If you point the easiest to skywave frequency of garage opener at the right vector at the right time could a properly positioned friend hear it by skywave? Sagittarian Milky Way (talk) 19:25, 14 November 2022 (UTC)
- They will only transmit at milliwatts of power and so be difficult to receive a long way off. So they would only work with a range of a few dozen meters. Also only those remotes that transmit around 28 MHz would reflect signals off the ionosphere at certain times of solar maximum. And for these frequencies the wavelength is much larger than the size of the remote, so there is no concentration of power in a beam. So "pointing" won't achieve anything. If your friend has a large Yagi or phased-array antenna they could be a few times further away and still receive a recognisable signal. Your friend will have a noise floor of cosmic noise and noise temperature (antenna) which will limit their ability, even with expensive equipment. And perhaps there will be interference, because there are other users of the radio channel. Graeme Bartlett (talk) 22:08, 14 November 2022 (UTC)
- If you point the easiest to skywave frequency of garage opener at the right vector at the right time could a properly positioned friend hear it by skywave? Sagittarian Milky Way (talk) 19:25, 14 November 2022 (UTC)
- So garage remote controls use a 4-digit code? I'm guessing a TV remote control is less? 67.165.185.178 (talk) 02:52, 15 November 2022 (UTC).
- TV remote controls do not transmit a series of decimal digits. There are various types and different communication protocols. The most common is multi-channel transfer, which can be seen as bit patterns transmitted in parallel, encoded as an FM signal. The RC-5 protocol has a width of 14 bits, but encodes for only 128 possible commands per transmitted pattern. --Lambiam 08:13, 15 November 2022 (UTC)
- So at 128 commands, channel up from 1 remote control can be channel down in another? Or, power-on in 1 remote can be channel-up in another TV? 67.165.185.178 (talk) 11:10, 15 November 2022 (UTC).
- That depends on 1) whether the two remotes operate on the same frequency bandwidth 2) whether the two remotes are operating the same protocols 3) how the remotes and TV translate the specific commands. Too many variables to say. I mean, anything is possible. In general though, as a consumer, you're going to want to use the remote that came with your TV; OR you're going to want to use a programmable universal remote control that can be programmed to behave like the remote that came with your TV. --Jayron32 12:56, 15 November 2022 (UTC)
- So Jayron/Lambiam and whoever, has TV remote controls changed (the protocols, frequency bandwidth, and translation) changed when we upgraded from regular TVs to flat-screen TVs? 67.165.185.178 (talk) 00:06, 16 November 2022 (UTC).
- Maybe? There are too many variables to count in terms of how different manufacturers might do things. Maybe some modern flat screen TVs use the same protocols as older CRT TVs. Maybe some have novel ways of doing their remote controls. It's way too variable to make any blanket statements. — Preceding unsigned comment added by Jayron32 (talk • contribs) 13:19, 16 November 2022 (UTC)
- So Jayron/Lambiam and whoever, has TV remote controls changed (the protocols, frequency bandwidth, and translation) changed when we upgraded from regular TVs to flat-screen TVs? 67.165.185.178 (talk) 00:06, 16 November 2022 (UTC).
- That depends on 1) whether the two remotes operate on the same frequency bandwidth 2) whether the two remotes are operating the same protocols 3) how the remotes and TV translate the specific commands. Too many variables to say. I mean, anything is possible. In general though, as a consumer, you're going to want to use the remote that came with your TV; OR you're going to want to use a programmable universal remote control that can be programmed to behave like the remote that came with your TV. --Jayron32 12:56, 15 November 2022 (UTC)
- So at 128 commands, channel up from 1 remote control can be channel down in another? Or, power-on in 1 remote can be channel-up in another TV? 67.165.185.178 (talk) 11:10, 15 November 2022 (UTC).
- TV remote controls do not transmit a series of decimal digits. There are various types and different communication protocols. The most common is multi-channel transfer, which can be seen as bit patterns transmitted in parallel, encoded as an FM signal. The RC-5 protocol has a width of 14 bits, but encodes for only 128 possible commands per transmitted pattern. --Lambiam 08:13, 15 November 2022 (UTC)
- So garage remote controls use a 4-digit code? I'm guessing a TV remote control is less? 67.165.185.178 (talk) 02:52, 15 November 2022 (UTC).
Okay, I looked at the Wikipedia articles for both garage remote control and TV remote control. For garage remote control, had multiple phases. 1st phase = remote control could work on your neighbors garage. Then 2nd phase, it had a 2^8 to 2^12 possible combinations, (maxing at 4,096). But it was still possible to save/record the wave, or try every possible combination. Then 3rd phase, had some 3 billion combos... However, article doesn't say from what years to what years the phases were but I am wondering for TV remote. Then, for TV remote controls, doesn't say about working for other people's TVs but that likely wasn't an issue. But here's a question. Why did when the 1st remote and garage control was invented, why was garage decided to be radio wave and TV decided to be IR wave? And not vice versa? 67.165.185.178 (talk) 23:58, 16 November 2022 (UTC).
- For a historical perspective, I wrote the article about the Zenith Radio Nurse, the first electronic baby monitor introduced in 1938. It failed because it interfered with early car radios and early garage door openers. Cullen328 (talk) 00:08, 17 November 2022 (UTC)
November 15
The amplitude of AC electricity.
DC electricity is AC electricity with a frequency of 0. So if frequency of 0, is a straight line, with 0 amplitude. Then AC electricity, is like a sine wave. What happens when you increase the amplitude? Increase in amps, or watts? 67.165.185.178 (talk) 00:07, 15 November 2022 (UTC).
- DC electricity would not have an amplitude of 0. You can measure the amplitude in Volts, Watts or Amps as you suspect. If you double the voltage when there is a resistive load, you will double the current (in Amps) and quadruple the power (in Watts). You can look at Root_mean_square#Average_power for how to work out power when the amplitude is fluctuating. Graeme Bartlett (talk) 00:31, 15 November 2022 (UTC)
- What would a sine curve graph look like with 0 frequency but has an amplitude? 67.165.185.178 (talk) 02:53, 15 November 2022 (UTC).
- that is invariant for and with non-zero amplitude is a horizontal line at some y-axis value, just like DC current (or voltage, or whatever you're measuring). DMacks (talk) 03:00, 15 November 2022 (UTC)
- Most definitions of amplitude assume a varying time signal, but in the case of a sine wave are proportional to the width of the range of the signal. For a constant signal, that width equals 0. Only using the sense of "peak amplitude" with another reference value than mean value will give a non-zero amplitude. --Lambiam 08:47, 16 November 2022 (UTC)
- that is invariant for and with non-zero amplitude is a horizontal line at some y-axis value, just like DC current (or voltage, or whatever you're measuring). DMacks (talk) 03:00, 15 November 2022 (UTC)
- What would a sine curve graph look like with 0 frequency but has an amplitude? 67.165.185.178 (talk) 02:53, 15 November 2022 (UTC).
- The premise that DC is a special case of AC is wrong. If it ain't got the vibe, it ain't alternating. DC can be seen as a limiting case of AC, though. The wave form of a pure-sine AC wave of amplitude and frequency can be expressed mathematically as a function of time by In this formula, stands for whatever the phase happens to be at time As the frequency gets arbitrarily close to 0, we obtain in the limit: so the current does not depend on the time but is constant. (The convergence to this limit is not uniform.) The strength can "freeze" to any value in the range from to just as when a lightning strike halts the clockwork of a clock tower, it can freeze the clock at 10:04 or any other display of its hands. --Lambiam 07:52, 15 November 2022 (UTC)
- Wait, can there be electricity with a frequency of 0? Can that be done for both AC and DC? 67.165.185.178 (talk) 02:36, 17 November 2022 (UTC).
- As explained above, a frequency of 0 means a constant value. By definition, for a current that means the same as being a direct current. Alternating current has, by definition, a frequency that is non-zero. --Lambiam 09:25, 17 November 2022 (UTC)
- Wait, can there be electricity with a frequency of 0? Can that be done for both AC and DC? 67.165.185.178 (talk) 02:36, 17 November 2022 (UTC).
What kind of small animals could hurt a Coelophysis?
What kind of small animals from the chinle formation have the weaponry to give nasty wounds to a Coelophysis that could get infected and cause the dinosaur to die? CuddleKing1993 (talk) 03:42, 15 November 2022 (UTC)
- Another coelophysid. Probably most contemporaneous small predatory theropods. --Lambiam 07:59, 15 November 2022 (UTC)
- What about other kinds of animals, like animals it would prey on? CuddleKing1993 (talk) 01:08, 16 November 2022 (UTC)
- Paleobiota of the Chinle Formation should give you an idea of what other animals were living at the same time. Mikenorton (talk) 17:25, 16 November 2022 (UTC)
- What about other kinds of animals, like animals it would prey on? CuddleKing1993 (talk) 01:08, 16 November 2022 (UTC)
Science experiment
My mom and I did a science experiment. We took a banana's peel off. The banana was supposed to turn into mush faster because the peel kept it safe. However, it still didn't turn into mush! Why is that? 67.215.28.226 (talk) 23:30, 15 November 2022 (UTC)
- Would go faster if you increase the temperature. 67.165.185.178 (talk) 23:50, 15 November 2022 (UTC).
- A possible explanation is that the supposition is wrong. Bananas normally turn soft because of natural ripening, which turns the starch in the banana into sugar (see Cavendish banana § Uses). Removing the peel does not speed up the ripening process. --Lambiam 08:28, 16 November 2022 (UTC)
- Thank you. And what I've used was indeed a Cavendish banana. 67.215.28.226 (talk) 18:35, 16 November 2022 (UTC)
- An experiment is a procedure carried out to support or refute a hypothesis. You and your mom succeeded in refuting your hypothesis, so your experiment has succeeded in what you set out to do. Shantavira|feed me 09:40, 16 November 2022 (UTC)
- Others have commented on the ideas that might give the outcome you observed. I'll comment on how you are testing your idea. You say it was expected to turn into mush faster. What's the basis or expectation for how long it would usually take? There can be a lot of natural variation in the original banana (how ripe it was when you started, how warm/cool it had been stored, whether the peel might already be damaged, etc.). So you're off to a good start: you made a prediction, did an experiment, and have a result. To make it a more complete experiment, you need what's called a control case to make sure you have a good reference for comparison. For example, if you have two bananas from the same original bunch, you can be pretty sure they are at equal starting conditions when you get them. Therefore "peel one, don't peel the other" and see which one becomes mush first. That's a more direct comparison than simply "the one banana I had didn't turn to mush in a certain amount of time". DMacks (talk) 09:53, 16 November 2022 (UTC)
- If I remember it well, banana ripening is associated to emissions of ethylene. Other fruits, including other bananas, may emit ethylene, so both the test banana and the control banana should be in the same conditions, including distance to other bananas and fruits. --Error (talk) 18:45, 16 November 2022 (UTC)
November 16
Tetanus shot
Jo had a tetanus shot in her butt. They usually give them in someone's arm, not their butt. By the way, Jo's height was 5 ft 6 in (165 cm) and weighed 88 lbs (40 kg). And, she was supposed to get a tetanus shot because she had a cat scratch. Rabies? Yes. But tetanus, I've never heard of. And it wasn't rabies, because, from what I've heard, it's 5 needles on the stomach. She got 1 needle on the butt. Why is that? 67.215.28.226 (talk) 18:21, 16 November 2022 (UTC)
- Did you ask her doctor? ←Baseball Bugs What's up, Doc? carrots→ 18:43, 16 November 2022 (UTC)
- Tetanus is caused by a bacterium called Clostridium tetani that is very commonly found all over the world. Although tetanus is popularly thought of as being found on rusty metal, that's not the case; it's pretty nearly universally found. So any scratch or cut could be the cause of an infection and a tetanus infection is no fun at all. Cat scratches are excellent ways of transmitting diseases (see Cat-scratch disease), probably because they tend to be deep but not bleed very much. So updating your tetanus booster when you get scratched is common. Matt Deres (talk) 18:53, 16 November 2022 (UTC)
- Then why did she get the needle in her butt, not her arm? 67.215.28.226 (talk) 18:57, 16 November 2022 (UTC)
- Why do you expect other people to look up this information for you? You have the answers two clicks and a bit of reading away. One click got me to Tetanus (which @Matt Deres kindly provided a link for you above where I learned that "mild cases of tetanus can be treated with Tetanus immunoglobulin (TIG), also called tetanus antibodies or tetanus antitoxin. It can be given as intravenous therapy or by intramuscular injection." A second click on the link at the end of that sentence took me to an article whose second paragraph informed me that "Common sites for intramuscular injections include the deltoid muscle of the upper arm and the gluteal muscle of the buttock." Further down the article, I read that "Injections into the deltoid site in the arm can result in unintentional damage to the radial and axillary nerves." Bazza (talk) 19:13, 16 November 2022 (UTC)
- Okay. I thought it might be because she was so small. Thanks anyway! :) 67.215.28.226 (talk) 19:16, 16 November 2022 (UTC)
- When I had a number of injections at around 6 years old (because my family was moving from the UK to Hong Kong), they caused a slightly scarred area on my upper left arm. I was told at the time that girls and women were often given the option of having injections in the posterior because female fashions often expose the upper arm, where such a scar might be unsightly, but on the buttocks it would be less-often seen. Males were presumed not to care about having a slight arm-scar. {The poster formerly known as 87.81.230.195} 90.217.47.60 (talk) 20:55, 16 November 2022 (UTC)
- Okay. I thought it might be because she was so small. Thanks anyway! :) 67.215.28.226 (talk) 19:16, 16 November 2022 (UTC)
So updating your tetanus booster when you get scratched is common
- Why do you expect other people to look up this information for you? You have the answers two clicks and a bit of reading away. One click got me to Tetanus (which @Matt Deres kindly provided a link for you above where I learned that "mild cases of tetanus can be treated with Tetanus immunoglobulin (TIG), also called tetanus antibodies or tetanus antitoxin. It can be given as intravenous therapy or by intramuscular injection." A second click on the link at the end of that sentence took me to an article whose second paragraph informed me that "Common sites for intramuscular injections include the deltoid muscle of the upper arm and the gluteal muscle of the buttock." Further down the article, I read that "Injections into the deltoid site in the arm can result in unintentional damage to the radial and axillary nerves." Bazza (talk) 19:13, 16 November 2022 (UTC)
- Recent studies have questioned the booster recommendation for most adults, arguing that lifelong immunity may be achieved with childhood vaccinations. However, this research is not conclusive and the CDC continues to adhere to the ten year booster recommendation. Viriditas (talk) 21:22, 16 November 2022 (UTC)
- Then why did she get the needle in her butt, not her arm? 67.215.28.226 (talk) 18:57, 16 November 2022 (UTC)
Considering that kritosaurini saurolophines and panoplosaurini nodosaurs have been found in South America, logically abelisaurs would have ventured into North America as well. CuddleKing1993 (talk) 21:49, 16 November 2022 (UTC)
- What's your question? ←Baseball Bugs What's up, Doc? carrots→ 22:32, 16 November 2022 (UTC)
- My question is how it can't be an abelisaur when the evidence is staring right in our faces. CuddleKing1993 (talk) 23:36, 16 November 2022 (UTC)
- When Labocania lived, in the late Cretaceous, North America was not connected to South America. The isthmus of Panama formed only about 3 million years ago. CodeTalker (talk) 00:22, 17 November 2022 (UTC)
- But the Allen Formation has saurolophine hadrosaurs and panoplosaurini nodosaurs so that arguement is invalid. CuddleKing1993 (talk) 01:00, 17 November 2022 (UTC)
- Taxonomic classification of fossil finds is based on characteristics of the fossils, such as body structures and their apparent functions. The location of the finds may offer supporting evidence, but can never be the basis. It is not clear what the questions is. What specific and concrete evidence is there for which specific classification? --Lambiam 09:18, 17 November 2022 (UTC)
- When Labocania lived, in the late Cretaceous, North America was not connected to South America. The isthmus of Panama formed only about 3 million years ago. CodeTalker (talk) 00:22, 17 November 2022 (UTC)
- My question is how it can't be an abelisaur when the evidence is staring right in our faces. CuddleKing1993 (talk) 23:36, 16 November 2022 (UTC)
November 17
Greatest science achievements from Australia?
Textbooks in the U.S. on science all list historical achievements from the U.S. and Europe. Probably none from Australia? Wikipedia's article even on TV remote control and garage remote control all says invited in U.S. I would like to see a textbook used in Australian colleges on biology, chemistry, and physics - even horticulture, to see if they actually list inventions/discoveries from Australia? I already had an earlier discussion on this page that the 1st genetically-modified blue rose was done in Australia, with the help of a Japanese company. Wonder what are some other famous 1sts in Australia. I would imagine a horticulture/botany textbook from Australia will be vastly different than in the U.S. or U.K. Anyone have who were the 1st from Australia to win the Nobel prize in sciences? 67.165.185.178 (talk) 02:34, 17 November 2022 (UTC).
- Start with Timeline of Australian inventions. List of Australian Nobel laureates may also be of interest. For a deeper dive, try Category:Australian science and technology awards-gadfium 03:40, 17 November 2022 (UTC)
What is the basis for which metal detectors detect liquids?
Which would mean, metals and liquids, have some common-ality. Does that mean metal detectors can detect water, but not ice? 67.165.185.178 (talk) 04:33, 17 November 2022 (UTC).
- Detection by metal detectors is based on electrical conductivity, which is about seven orders of magnitude higher for metals than for water, fluid or frozen. In other words, metal detectors are just as useless for detecting liquids (other than mercury) as dowsing rods. --Lambiam 08:52, 17 November 2022 (UTC)
My mom's menstrual cycles
The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.
My mom has painful menstrual cycles every other one (her average menstrual cycles are about 30.5 days long. One menstrual cycle, she could barely feel it, but the other one seems to be the "hurtful" one. She takes a Midol whenever those cycles come. Why is that, I wonder? 67.215.28.226 (talk) 04:52, 17 November 2022 (UTC)
- Questions asking for medical advice, which this is, are not allowed here. Sorry. --174.89.144.126 (talk) 05:33, 17 November 2022 (UTC)
- Oh, okay. 67.215.28.226 (talk) 05:45, 17 November 2022 (UTC)
- Without being diagnostic: consider the fact that women usually have two ovaries, and these usually ovulate alternately. What you describe is not uncommon; it's even a currently ongoing plot point in the webcomic Dumbing of Age. {The poster formerly known as 87.81.230.195} 90.217.47.60 (talk) 11:22, 17 November 2022 (UTC)
- Oh, okay. 67.215.28.226 (talk) 05:45, 17 November 2022 (UTC)
- What has her doctor said about this? ←Baseball Bugs What's up, Doc? carrots→ 12:11, 17 November 2022 (UTC)