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July 4

Bullet Energy and Height

My friend and I are developing a homebrew pen and paper combat game where each player moves miniatures around on a board and shoots at the other team. To make things more interesting, we added vertical elevation into the mix. This lead to the following debate: on the one side, it feels like - for a fixed horizontal distance - that adding elevation should make the bullet have more energy when it arrives at the target because of gravity; however, increasing elevation also increases the distance from the target, which feels like it should reduce the bullets energy when it arrives at the target. So, how does adding elevation affect the energy of the bullet upon reaching the target - does terminal velocity factor in? I find the question a little more fascinating than the rules of the game (will probably just go with whatever feels best to us), it is the actual science of the thing that seems neat here, I'd love to know what all variables are involved and what the broadest possible result is. Thank you for any help:-)24.3.61.185 (talk) 09:36, 4 July 2019 (UTC)

There's a well-known effect that elevation relative to the target increases artillery range (although most of that is just due to there not being any ground to hit when it loses elevation), but I'm not sure if the same would apply to bullets, since air resistance is more of a factor there. Ideally, the gravitational potential energy would transform into kinetic energy closer to the end, so that the increased velocity would occur then, not near the start, where increased velocity would also increase aerodynamic drag. SinisterLefty (talk) 09:57, 4 July 2019 (UTC)

Doing some really rough calculations. A 7.62x51mm Nato bullet is 10g, dropping it from 35 meters in height should 3.43 joules at impact. A 7.62x39mm bullet will have 1119 joules of energy at 100 yards and 813 joules at 200 yards. So, supposing the target was a horizontal distance of 120 meters and that linearly interpolate energy from 100 to 200 yards (which isn't accurate, but good enough for a rough-ish estimate), that's 1056 joules at point of impact. If we raise the shooter 35 meters into the air, that changes the distance to 125 meters, giving 1043 joules + 3 joules from gravity = 1046 joules (the 39 is lighter, but 3 seems decent). So, going by that, it looks like there would be little difference, but favouring the non-elevated shooter. Raising the elevation to 70 meters drops the joules at impact to around 1005ish, more so in favour of the ground based shooter. Of course, I'm sure something is being neglected, here, since these are very rough methods, but it does seem to favour the ground level shooter. Though, since most people aren't going to be shooting from elevations exceeding 30 meters, it seems like there wouldn't be any appreciable difference - for larger horizontal ranges, the gap should close even more, eventually winning out for the elevated shooter, but not by a lot and at distances that would severely reduce accuracy. All that said, I feel like I must be missing something, physics is not my strong suit.24.3.61.185 (talk) 10:33, 4 July 2019 (UTC)

• A quantitative answer involving air resistance, velocity calculations etc. is hard to give, but a qualitative answer is fairly easy to come by.

The question can be converted into whether a gun located at $x=0,z=z_{0}>0$ can hit a target located at $x=x_{t},z=0$, assuming the same gun can hit the same target when located at $x=0,z=0$. In the higher position, if the bullet is fired with the same angle, it with pass through the point $x=x_{t},z=z_{0}$ and continue, falling down somewhere beyond the target. On the other hand, it is trivial to shoot the bullet somewhere closer to the shooter than the target is, say, towards $x=0,z=0$. Because the position of the intersection of the bullet trajectory and the ground is a continuous function of all parameters at hand (this seems obvious, but it is not true in general; proving it is true in the case at hand would involve lots of math that I am not sure to be able to do), the intermediate value theorem ensures there is some settings for which the bullet reaches the target.

As for whether the energy hitting the target would be higher or lower, both can happen. If the bullet speed just outside the rifle is gigantic (far above free fall terminal speed), and the target is very close on the x-axis, then the dominant effect is friction dissipating the initial kinetic energy, so a point-blank shot would do more damage. On the other hand, if the target is very far, the bullet speed is low and the height difference is huge, the dominant effect will be bullet acceleration due to gravity. Not sure how to put that into a nice adimensional number, though... Tigraan^{Click here to contact me} 10:28, 4 July 2019 (UTC)

Practical shooting teach that you have two situations:

If the trajectory is basically a straight line (as opposed to: significantly parabolic), that is, if the target is close enough in respect to the speed of the bullet), so that you don't need Iron_sights#Adjustment: you just don't care about height and gravity

If not, just don't shoot, you'll miss unless you ARE a sharpshooter

This is not an energy problem, rather an aiming problem.

Gem fr (talk) 23:12, 4 July 2019 (UTC)

External_ballistics deals mathematically with the trajectory of a bullet in flight. Gravity can add to the bullet's energy on hitting the target only if the shooter is at higher elevation than the target, and then by only by a tiny amount corresponding to its fall during the short time of travel. A Terminal_velocity is the limit to the downward velocity of a free-falling object where atmospheric drag equals its weight so that it cannot be further accelerated. For a Parachute terminal velocity is slow and is quickly reached but a bullet is normally stopped by a target well before its rate of fall reaches terminal velocity. DroneB (talk) 09:01, 5 July 2019 (UTC)

Particle/ projectile emitted from neutron star or white dwarf

If someone throws a rock straight up on the moon or some other airless planet, I can estimate the changes in velocity with v=v1-at and v^2-v1^2=2a(y-y1), with a=gravity acceleration and y height. For a projectile that starts faster i think i would have to use change in kinetic energy =k(1/y -1/y1), since the force of gravity falls off as y^-2. What about a projectile from a white dwarf(if it were rotating slowly or not at all for simplicity)? Would relativistic effect change the formulas? Thanks! Rich (talk) 18:39, 4 July 2019 (UTC)

Not that much. Ruslik_Zero 19:47, 4 July 2019 (UTC)

July 5

chemistry clarification

Since two different compounds always have at least one different chemical properties (i.e., chemical reactions).

Now if isomers are different chemical compounds, then how do i prove that any two isomeric structures always have different set of chemical reactions?

In the case of optical isomerism where there a little change in orientation in space occurs, i don't think any of its reaction got effected, even if it happened with one then what's the surety for such to all. Suyogya1 (talk) 14:25, 5 July 2019 (UTC)

Enantiomers might have different rates of reaction (see asymmetric induction), and often have different covalent and/or ionic binding affinities (affecting things like solubility, chromatographic mobility, etc.) against other chiral substances. Be careful not to think that "chemical reactions" are the only aspect of a chemical that are "properties" of that chemical. DMacks (talk) 14:46, 5 July 2019 (UTC)

It's also important to note that some of our traditional "boundaries" we set in these definitions are arbitrary anyways. We say things like dissolving and phases changes are "physical" and not "chemical" changes, but that's not because there's a fundamental difference between those changes and other "chemical" changes. Humans need to create categories to break our world into more manageable pieces, but when you really start to look at what's going on, there's a lot less different at the edge cases than we presume. It's all breaking and forming bonds, that is working against or with electrostatic forces. What we call a "molecule" or an "ion" or a "chemical bond" or a "intermolecular bond" are all differences in quantity, not in character. It's all the same thing at the basic level.--Jayron32 17:08, 5 July 2019 (UTC)

Molecular compounds

1. Why do we use nona- rather than ennea- for 9??
2. Why do we use mono- for the second word of an element's name but not the first??
3. Why do we treat hydrogen like its atomic number is 7 1/2 for the purpose of ordering it??
4. Why can krypton and xenon (which are noble gases) form compounds?? Georgia guy (talk) 17:47, 5 July 2019 (UTC)

(Please make sure you know exactly what I mean when it comes to question #3. Hydrogen has the atomic number of 1, but for the purpose of ordering it in binary molecular compounds, it's more like its atomic number is 7 1/2, only on the highest row rather than the second highest row.) Georgia guy (talk) 17:47, 5 July 2019 (UTC)

3) Note that hydrogen was placed in 2 positions on the Mendeleev Periodic Table of the Elements: [1]. SinisterLefty (talk) 17:57, 5 July 2019 (UTC)

The answer to #4 can be found in the Wikipedia article titled noble gas compound. The answer to the other three is the same basic answer: Language is not a rigid, perfectly consistent system. The language of chemistry evolved, over many centuries, like other languages have, and it is not, has not been, and likely will never be, a perfectly self-consistent system. For example, on the issue of not using "mono" for the first element, that is a historical artifact of how chemical compound formulas were determined: you took something and burned it in oxygen, then figured out the molar ratio of that stuff to oxygen. That would give you the prefix for the oxide portion, and the first word was always assumed to be one. There were even fractional prefixes like sesquioxide used in cases like Fe2O3. The system of using prefixes for the first element came about over a century after these earlier systems existed, due to a new a different understanding of how chemistry works. Anytime you graft a new system on to an older system, there are GOING to be inconsistencies. After all, we still use words like "ethane" and "propane" and not "diane" and "triane". Why? Because there's no benefit from changing from the words we already used for centuries. Language will always be messy.--Jayron32 18:03, 5 July 2019 (UTC)

Issue 1 is even more widespread than "chemistry"...polygons are octagon but nonagon only has as a presumably rare synonym enneagon. Chemistry presumably followed the pre-existing naming of "a series with increasing numbers of things". Jayron32 is right...language is organic (pun intended). DMacks (talk) 19:02, 5 July 2019 (UTC)

I laughed, but what does that final sentence mean?? Georgia guy (talk) 19:08, 5 July 2019 (UTC)

See wikt:organic adjective definition #9. The alkyl series n≥5 doesn't follow a single language's prefixes (the question is about why not all Greek, but instead mixed with some Latin). But that alkyl series exactly matches the polygon names. So the chemistry actually does exactly build on an antecedent, that itself isn't single-language, but presumably was built up over time from...dunno. DMacks (talk) 20:52, 5 July 2019 (UTC)

Bottle Cap Challenge

In the recently trendy Bottle Cap Challenge a bottle cap has been unscrewed particularly by a roundhouse kick, ice skate kick and gymnastic juggling club. My understanding is that in all instances the cap has been slightly loosened beforehand, as otherwise it would be nearly impossible due to lever principle (where after fixing the bottle a strong grasping force is applied in addition to rotation). What physics comes into play here? 212.180.235.46 (talk) 20:16, 5 July 2019 (UTC)

You need a certain amount of torque to open the bottle cap (far less if the seal has been broken), and that is force times the distance from the center of the cap. Any kind of striking motion will have the problem that that force is applied over a very small area, creating high pressure, breaking the bottle or ripping the cap open. When using your hand to open a bottle cap, the force is distributed evenly over a much wider area. There's also something called an impact, where the force is applied so quickly the object doesn't have time to absorb the force and distribute it evenly by deforming (bending) slightly, and instead fractures. An example of this is when high speed photography is used on a bullet going through a rubber sheet. Instead of stretching, the rubber shatters like glass. SinisterLefty (talk) 20:31, 5 July 2019 (UTC)

You need torque indeed. The trouble is, you don't have torque by applying a single force, you need 2. The force from the kick is pretty much unlimited. The second force comes from the way the bottle is held. If it is firmly held by a sidekick (pun intend), glued, or whatever, then the force will be just equal and opposite to the force coming from the kick, and it will work; besides, the kicker won't have to be so precise, if he kicks too far, the second force will keep his foot in place. If not firmly held, chance are the bottle will tip over; to avoid that, you'll need a heavy bottle (ie: glass, not plastic) for maximum inertia, with a metal cap that has low friction against the glass. Notice many video show the cap of the bottle and you dont know if and how how it is held. Sometime the sidekick, holding the bottle (and even applying is own strength against the kicker shoe), is on the video. Gem fr (talk) 22:19, 5 July 2019 (UTC)

• Mostly momentum, impulse and inertia. Torque only comes into it later.

As noted, it takes two forces to produce a torque. These come from whatever hits the cap, and from the bottle itself. These should give rise to a couple on the cap, which gives a torque, which causes rotation. If it's not a balanced couple, the bottle falls over. But before you get that couple, you have a (quite complicated) process where the momentum of the foot / shoe sole hits the cap and delivers an impulse. As all of these things are also flexible, a lot goes on before it resolves into a simple couple.

You can analyse this (high school Newtonian mechanics) as a rigid bottle and an impulse from the foot. You've simplified this by making the bottle rigid rather than elastic. But the real situation is going to be more complicated, and tricky. Andy Dingley (talk) 11:22, 6 July 2019 (UTC)

July 6

composition

Pure substance have a fixed composition i.e., for water it is 1:8 (hydrogen:oxygen). An element is a pure substance, but how does it has ratio of its atoms in its lattice i.e., How to define element's chemical composition? Suyogya1 (talk) 02:50, 6 July 2019 (UTC)

There are single element molecules, like H₂ (diatomic hydrogen gas). Then there are crystals made of a single element, like diamond, made of carbon. To determine the density of such a crystal, you need to determine which type of crystal lattice it forms. Each has a characteristic percentage occupied by atoms, and the rest is empty. Of course, these empty spaces also need to be considered in determining the density of crystals made of two or more elements, like table salt crystals (NaCl). And obviously the density of the atoms also plays a role. And in the case of hollow crystals, like buckyballs/fullerene and buckytubes/carbon nanotubes, the contents, if any, of the hollow spaces must also be considered. SinisterLefty (talk) 03:36, 6 July 2019 (UTC)

Strange question. The "lattice" is not an element, it makes no sense to compare the 1:8 (hydrogen:oxygen) mass ratio of water, to the "ratio of its atoms in its lattice". For a pure element (like: a simple copper wire), the mass ratio is simply 1:1. Now, crystallography does define something which may be what you are looking for: crystal system. You may find lattice constant of interest, too. Or may beyou are just looking for density? Gem fr (talk) 07:12, 6 July 2019 (UTC)

Yellow substance from tomatoes

Dears users of en.wikipedia, good morning. I try to write to you a question in my bad English, sorry for the grammar errors.

In my house garden I cultivate tomatoes. Every time I pick up the tomatoes from the plant, a yellow and powdery substance remains in my hands. I can remove this substance only with the Marseille soap degreaser. Someone can tell me what is the name of this substance. Thank you for the attention.

--87.8.151.65 (talk) 10:44, 6 July 2019 (UTC)

Could it be Pollen? The waxes and proteins on the surface of the granules can make it difficult to remove. Dbfirs 10:54, 6 July 2019 (UTC)

Is it possible? Can the pollen be on all surface of the skin of sigle tomato? On Google I find the tomato tar, but for my low knowledge the tar is the thing with which streets and roads are made, and seems a slang word to indicate something (pollen?). Thank you Dbfirs for answer me.--87.8.151.65 (talk) 12:07, 6 July 2019 (UTC)

If it's on the surface of the tomato, then pollen seems unlikely. Dbfirs 06:20, 7 July 2019 (UTC)

Yes, tomato tar seems to be the answer: [2]. That is an unusual usage of the word "tar", I agree, probably because it's sticky like tar. Here's more on the cause and how to remove it: [3]. It seems to be acid-soluble and serves the function of sticking to insects to drive them away. If anyone feels like making an article, those two links would be a good start. SinisterLefty (talk) 12:19, 6 July 2019 (UTC)

Wow, I know exactly what the OP means, but have never been inspired to find out more. SinisterLefty above has pinned it down. I also found this - [4]. It has lots of details. One bit says "These substances are thought to protect plants against environmental assaults including insect attacks, foliar diseases, extreme heat and excessive light." I have always thought of the stuff as being green, rather than yellow, but I can tell we're talking about the same thing. For washing it off, I use a product known here in Australia as Solvol, again something I've never thought much about, and a look around on the web tells me it's not known by that name elsewhere. I don't know what it might be called. It has bits of ground pumice in a soap bar. Not as hard on your skin as it might sound. Good luck finding your local equivalent. HiLo48 (talk) 12:38, 6 July 2019 (UTC)

ADDENDUM: It seems that Lava (soap) might be the equivalent American product to what I know as Solvol. HiLo48 (talk) 12:45, 6 July 2019 (UTC)

My second source suggests using vinegar, since it's acid-soluble. Might be less harsh on the hands. Tomato tar also seems to change colors when it reacts with various chemicals found in cleaning products, ranging from yellow to green to brown to black. And of course it will look different on a red or green tomato than on a white towel. SinisterLefty (talk) 13:00, 6 July 2019 (UTC)

May be previous answer are good, but my first thought was you are facing some pest. In my mind, yellow+sticky prompts: Scale insect. I'll browse your favorite pest-control Internet resource if I were you. Gem fr (talk) 14:23, 6 July 2019 (UTC)

DNA Replication Video cont´d

Version 2

DNA Replication / Video Version 2 ad user:wnt, user:DMacks et al

Based on the comments by the users wnt and DMacks I have implemented the subsequent modifications to my original model from 26.06.2019:
1 As per wnt: The enzyme helicase only unwinds a short portion of the double helix to generate a “flat” molecular section for further replicative steps. The remaining part of the DNA remains coiled in the form of a double helix.
2 As per DMacks: In the replicative phase I have shown the nucleobases A/T/C/G (represented by differently coloured sticks) being synthesised in their proper sequence as determined by the pre-existing nucleobases on the leading / lagging strands.
3 As per DMacks: I have replaced the original backbones (which were shown as tubular helices) with individual balls. I have used different colours to indicate the antiparallel directionalities (3´- 5´ vs 5´- 3´) on the leading vs lagging strands. DMacks has suggested arrows for this purpose, but I was unable to achieve that.

? Is it permissible to include an existing WP image in the movie as a PiP (picture in picture) or similar? Required references to the licence can be added as a text panel at the end / start. It seems silly to reinvent the wheel for small details.
? Where do I pose technical questions? I am a Mac user and need to convert .mov documents to .ogg.

Please reevaluate and state if the model in the current form can be added to article space. Alternatively please specify any additional improvements required. I am not a biologist / geneticist but a humble IT geometer, so thank you for any help relating to scientific details.
--Cookatoo.ergo.ZooM (talk) 15:23, 6 July 2019 (UTC)

Another video for comparison: [5] DroneB (talk) 23:49, 6 July 2019 (UTC)

"Is it permissible to include an existing WP image": Yes this is normally possible. If the original is under a free license, it will allow derivatives, and so you can include it in a movie.

"Where do I pose technical questions" There is also the computing reference desk. To do the conversion you suggest, perhaps ffmpeg can do that. (ffmpeg -i x.mov x.ogg) Graeme Bartlett (talk) 22:24, 10 July 2019 (UTC)

Compounds and radioactive decay

Imagine that radioactive atoms react with stable atoms and form ionic bonds. When the radioactive atoms decay, what will happen to the compound? A good example is radium chloride, but I don't see anything there about what happens to the chlorine when the radium becomes radon (maybe it's freed, since RaCl2 "was also used in medicine to produce radon gas which in turn was used as a cancer treatment"?), and I couldn't find anything relevant in ionic bond or radioactive decay. Nyttend (talk) 20:53, 6 July 2019 (UTC)

I don't have a full answer to your question as asked and no time now to look further, but doi:10.1126/science.250.4979.392 is on this topic and might be a place to start chasing refs. DMacks (talk) 02:59, 7 July 2019 (UTC)

Many times the compound will be disrupted. If an alpha particle is emitted, the remaining atom will have two extra electrons. Rn²⁻Cl₂ would be very unstable and it is very likely the chlorine will take the electrons and move away. For atoms that undergo beta decay, the nucleus becomes more positive, and electrons remain the same, so a temporary molecule may result. Eg a tritium molecule decaying, will first form the helium hydride ion, as the recoil of the nucleus from the decay is not enough to break the chemical bond. T₂ → HeT⁺. Though most beta decays are much more energetic and could seriously damage the compound.Graeme Bartlett (talk) 05:20, 7 July 2019 (UTC)

You mean all the time. Radioactive decay comes with liberation of much more energy than a chemical bond can withstand: decay energy can be anywhere between a few keV to MeV, while chemical bond are just a few eV (for ref: Electronvolt#Energy_comparisons) (ionic bonding is a special case of chemical bonding) . Even the weakest decay will inject in the compound hundred of time to much energy, and will blow it apart. Gem fr (talk) 13:36, 7 July 2019 (UTC)

While you are correct about the total energy of decay, you are not correct that this energy always stays at the site of decay. Did you forget that decay involves ejection of particles or rays, which can carry away significant amounts of energy? Our decay technique article (the topic of the lead ref I noted) notes as a general pattern that the beta decay of tritium in a tritiated organic structure leaves the helium atom in the structure with only 1.6 eV (not keV or MeV). And that same article of ours also notes the same thing that Graeme Bartlett did: that the remaining energy is not enough to break the helium–tritium bond, but is instead a synehtically useful way of making that convalent structure by tritium decay. DMacks (talk) 15:42, 7 July 2019 (UTC)

You are right, the energy will not stay at the site of decay, most of it will go with the lighter particle emitted. Still, 1.6 eV is too much for a chemical bond, and I think you misread the article, which says that The bond between the carbon atom and the helium-3 ion ... is broken by the recoil. The helium atom almost always leaves as a neutral 3He. Well, I admit that all the time was an overstatement, but, still... (BTW thanks, I didn't knew this decay technique, which I find smart, although of limited practicality) Gem fr (talk) 16:25, 7 July 2019 (UTC)

Exactly...there is still remaining energy that is high enough to break many types of covalent bonds, just not all. He–Li, He–Be, and He-Be are expected to survive from tritium decay. And other elements can also decay to give stable products, such as in the first sucessful synthesis of perbromate (beta-decay of selenate). I'm updating our decay technique article, and it should probably be renamed but I'm not sure to what. DMacks (talk) 20:31, 7 July 2019 (UTC)

Well, I stand corrected. I am still doubtful that the survival is the normal case, but I totally lack expertise and ref to support this view so I back down. I see no problem with the current name of the article; it could use a (chemistry) tag in the title if there were a decay technique in other field that we mentioned in WP, but this is not the case, so... Gem fr (talk) 22:17, 7 July 2019 (UTC)

Surprisingly, the very similar radium fluoride RaF₂ really can become RnF₂ when the radium alpha decays (10.1524/ract.1983.32.13.163). This sort of thing has been used to reduce the amount of Rn emitted by targets when they are irradiated. RnF₂ has a low volatility and is probably an ionic compound(!): Radon#Chemical properties has more information about Rn chemistry. Double sharp (talk) 07:53, 10 July 2019 (UTC)

July 7

Freezing

When most people speak colloquially about freezing temperatures (such as, "Man, it's freezing in here!"), they are referring to the freezing point of water and remarking about how chilly it is. Since materials like aluminum and gold are solid at room temperature, does that mean that they are frozen, in the sense of freezing point referring to the temperature at which liquids turn to solids, the same as melting point, only in the opposite direction? So that's my first question -- are these sorts of materials properly (technically) referred to as being frozen at room temperature?

My second question, based off of this idea, is about jello. If jello sets at, let's say, room temperature, so that when it's made by boiling up in a pot and then left to cool in the mold on the counter, is that referred to as frozen at room temperature? Because unlike aluminum, say, which if it were to be placed in a freezer, would just get cold, and not undergo any phase change, jello placed into a freezer does turn into ice, which sort of betrays it's solid nature at room temperature as not really being solid. Is this is same problem with, say, a human body or an animal which, at room temperature, is what, 60% water but presents as a solid, but that if put into a freezer does indeed become a new type of solid at 0 degrees F.

Thanks! DRosenbach ^{(Talk | Contribs)} 04:36, 7 July 2019 (UTC)

On the subject of solid metals, yes, they are frozen. Though it's worth noting that as water/ice is being held together by hydrogen bonds, it does not display the same ductility near the melting point as do most metals, held together by metallic bonds. Jello is actually a gel, which is a complex phase of matter. It is not purely liquid or solid, but rather contains a liquid mass held to shape by a less dense solid scaffold. When molten jello solidifies, that is the solidification, or rather, immobilization-by-crosslinking of the gelatin it contains. The water is still in a liquid phase. When you then cool jello even further, the water itself eventually freezes, giving you another level of "frozen". Someguy1221 (talk) 04:50, 7 July 2019 (UTC)

Reiterating some points in the previous reply: yes, they are frozen, though because of the connotation of "frozen" in everyday language with the specific behavior of water, you don't hear the word much in such contexts. And, regarding the second question, the bright-line division between solid, liquid, and gas states is a property only of pure substances, which include water (with negligible contaminants) and pure elements. Mixtures like gelatin can have all kinds of complex behavior, and cannot be described accurately with the classical states of matter. Gelatin is a gel, with the collagen molecules forming a dispersed network throughout a liquid water solution. If you freeze the water, now you have a block of ice with stuff in it. The gel properties require liquid water to be present. --47.146.63.87 (talk) 07:10, 7 July 2019 (UTC)

As far as freezing a human or other animal, there are many distinct materials, with different freezing points. Pure water freezes at 32 F, but most of the water in animals is mixed with other constituents, so has a variety of freezing temps. Then there are oils, which behave somewhat like gels, in that they undergo viscosity changes at different temperatures, but don't actually freeze solid until quite low temps. SinisterLefty (talk) 18:42, 7 July 2019 (UTC)

Health and safety

Is health and safety subjective? Many countries like the UK or Germany who have high health and safety standards often criticise practices in other countries such as USA or UK which also have high health and safety standards but just do things differently. So at a certain point, does health and safety just become subjective? — Preceding unsigned comment added by 90.194.62.45 (talk) 07:38, 7 July 2019 (UTC)

Death rates are objective measures. Someguy1221 (talk) 07:44, 7 July 2019 (UTC)

But death rates are often similar between countries with high health and safety standards regardless of differing practices. 90.194.62.45 (talk) 09:10, 7 July 2019 (UTC)

That's why you need a much more specific query. The United States has similar death rates to some other countries for some causes, and very different death rates for others. See [6] for an overview. Certainly, "Western Europe good, America bad" is an oversimplification, and even if based on some average safety/health outcome, is an example of the ecological fallacy (assuming that every member of the group has the average qualities of the group). However, there are certainly examples where the United States is far behind other developed nations in health and safety, as you can see in that link. There are also objective measures beyond death rates. But essentially, you need to look at the individual practices being criticized to judge whether the criticism makes sense. Someguy1221 (talk) 09:37, 7 July 2019 (UTC)

In everything you'll find some subjectiveness. Still, Health can be assessed by a number of objective measures (vaccination, food intake Vs need, drinking of uncontaminated water,...). Same for safety (car-crash, death and injuries at work, ...). Gem fr (talk) 12:57, 7 July 2019 (UTC)

This summary has comparisons of worker deaths in the U.S. and EU. The overall rate is similar (2.8/100000 EU vs. 3.1 for U.S.) but individual industry rates vary more widely. Rmhermen (talk) 17:06, 7 July 2019 (UTC)

An interesting example of "doing things differently but with the same goal" is that eggs in the US must be washed before they are sold, to eliminate contaminated feces on them, while in Europe, they are banned from washing them, because this also removes an anti-microbial natural barrier layer (https://www.forbes.com/sites/nadiaarumugam/2012/10/25/why-american-eggs-would-be-illegal-in-a-british-supermarket-and-vice-versa/#47b28b3f4050).

Note that mortality from some causes can't be equalized. Suicides, for example, seem more prevalent in Arctic regions where sunlight is wildly uneven. This is related to seasonal affective disorder. Meds and bright light to simulate sunshine help, but do not eliminate, this problem. SinisterLefty (talk) 18:16, 7 July 2019 (UTC)

One example I find interesting is railway safety. Rail travel has a much better safety record than car travel, which is why even minor accidents to passenger trains make the news. But in order to keep rail travel as safe as possible, its regulatory authorities may insist on measures being taken which add to the cost of operating trains (thus raising ticket prices), or reduce the capacity of the railway (by reducing the speed or frequency of the trains). The regulators are happy because the deaths due to rail travel go down, but if the detriments I mentioned make people choose car travel instead, the total deaths may very well go up. --76.69.117.113 (talk) 19:47, 7 July 2019 (UTC)

Yes, they need to take a holistic approach. Similarly, doctors sometimes treat patients for one condition, not worrying about the side effects it may cause, which may be worse than the original problem. They need to look at what improves the patient's health overall the most, not just the condition they are treating. SinisterLefty (talk) 20:33, 7 July 2019 (UTC)

Another factor that comes into play is that enforcement can be highly subjective. Jurisdiction A might have stricter rules on the books than jurisdiction B, but if in jurisdiction B the rules are enforced fairly and uniformly across the board, while in jurisdiction A they're routinely ignored, or enforced depending on how well the inspector knows the family owning the inspected entity, or on how big a bribe the inspected entity pays to the inspector, then jurisdiction B might have better outcomes. —Steve Summit (talk) 02:11, 8 July 2019 (UTC)

Finding Lalande Prize recipients

Hi, I was wondering if anyone can advise how to find Lalande Prize recipients from 1939-1969. Article does not have a complete list, and I could not find any mention of such winners (although I found sources for one winner in 1960, and that the prize was until 1970). Golan's mom (talk) 10:37, 7 July 2019 (UTC)

They seem to be published in L'Astronomie each year in a section labelled "Nouvelles de la Science, Variétés, Informations". I have added a couple. Graeme Bartlett (talk) 12:51, 7 July 2019 (UTC)

Thanks Graeme Bartlett for adding and showing me where to look. I will try to see if I find some more. Golan's mom (talk) 07:18, 8 July 2019 (UTC)

Greg Marchand (surgeon): Is this article legit?

Many of the cites are misleading. Like an inline cite to biographical info takes to a blog where he is quoted on when to induce labor. I am guessing an elaborate hoax or a quack going on a publicity rampage because no links I click from the article gives anything helpful, instead it looks like a lot of circular referencing. Did he really invent the things it says he did? Does that make him notable? Are the papers listed published in reliable medical journals? Independent search yielded some promotional coverage in local media, one other source said his methods are unacceptable because it can spread cancer cells throughout the body. Couldn't find more. I don't know if this is the kind of thing that this place is for. But I don't know of any place else more suitable. Usedtobecool ^✉️ ✨ 21:27, 7 July 2019 (UTC)

Methink it is not legit, but I am on the "perfection is when you cannot cut a single word" side. Ref desk is indeed not the place to discuss such matter, however Ref Desk do can link to the proper place: Wikipedia:Articles for deletion. Gem fr (talk) 22:27, 7 July 2019 (UTC)

There really is a Dr. Greg Marchand in Arizona [7]. No comment on the content of the article, though. Someguy1221 (talk) 23:33, 7 July 2019 (UTC)

being real is far from enough to deserve an article, so far (although I suspect WP will end with a bio of just every person and their pets) Gem fr (talk) 00:09, 8 July 2019 (UTC)

This is now being discussed on WikiProject Medicine. SpicyMilkBoy (talk) 01:12, 8 July 2019 (UTC)

Thank you, editors. I didn't want to rush into AfD with the level of uncertainty I had but moving the discussion to the project page seems the best thing. Thanks for already taking it there. I will follow the discussion there.Thanks everyone. Feel free to close this discussion here. Usedtobecool ^✉️ ✨ 07:20, 8 July 2019 (UTC)

July 8

Speed of Light - Formation of images

We can see light via our eyes either directly or if it reflected off from the object.

Sunlight reaches earth.jpg Sunlight takes an average of 8 min and 20 sec to reach the earth. The speed of the light is 299,792 kilometers per second.

The sun is 109 times bigger than the earth. It radiates light in all direction. Earth receives a very small fraction (less 1% of the sunlight - guess). We are unable to see the rest of the sun lights as it fall in the space-like region and their direction of traveling keep them away further in the space-like region of light-cone - true. Therefore

How come we are able to see the full image of the sun when more than 99% of the sunlight doesn’t even fall on the earth (falls away into the space-like region of the light cone)? No reflections involve either – And the same is applied to the stars, galaxies, and image of the BH, etc.

Would the interference of light rays from these cones nullify the formation of shadows on earth? — Preceding unsigned comment added by Eclectic Eccentric Kamikaze (talk • contribs) 03:56, 8 July 2019 (UTC)

For an accurate idea of how the Sun emits light, you must keep in mind that rays of light do not only emit perpendicular to its surface (as if it had a smooth surface anyway). Every point on the surface of the sun is emitting light in every outward direction. We can see the whole of the sun because for each part of it that we can look at, some light rays are being emitted from that part toward our direction. Someguy1221 (talk) 04:01, 8 July 2019 (UTC)

1)far less than 1%. More like surface of the Earth disc / area of a sphere which radius is the sun-earth distance πR²/4πD², were R=6,371 and D=149,598,023. That is, less than 0.5 e-9 (half a billionth)

2)well, because that the definition of an image. Why would you need to see all the light emitted/reflected? a small fraction will do, as evidenced by the possibility to get image by photographing, when the collected light comes a fraction of a second. And it apply just as well to a computer screen or a chair in front of you. Gem fr (talk) 06:42, 8 July 2019 (UTC)

3)interference have requirement, which are explained here; Wave_interference#Light_source_requirements. These are not met as far as the sun is concerned. To be more precise, they are met by a so small fraction of the sunlight, that we cannot see any difference. Gem fr (talk) 06:42, 8 July 2019 (UTC)

Not a satisfactory answer (to me) but still, it's not 100% guarantee that we would get the same amount of light especially its distribution throughout the year when the earth orbit around the sun, therefore, shouldn’t the sun change its shape with the passage of time? — Preceding unsigned comment added by Eclectic Eccentric Kamikaze (talk • contribs) 04:47, 8 July 2019 (UTC)

in fact we DON'T get the same amount of light throughout the year when the earth orbit around the sun. The so called solar constant is not really a constant, as physicists define them. Gem fr (talk) 06:42, 8 July 2019 (UTC)

If you're talking about the sun changing shape due to perspective, no for two reasons: A) The sun is approximately a sphere, and so its projection is a circle from any distance; B) the distance from the Earth to the Sun does not change that much over the course of the year, only a few percent. I think you need a better idea of your own idea. Make another diagram, but trace every light ray that reaches your earth-bound observer from the sun. Try to figure out what that means, and then come back here if you still have questions. (Okay, not literally every light ray, but get the whole range of angles from which they will reach your observer.) Someguy1221 (talk) 21:37, 8 July 2019 (UTC)

It’s just a tentative diagram for the purpose of understanding only. I’m talking about the same image and appearance of the sun, which is like disc over the period of time. No problem with light rays fall directly on earth but it is the intensity, distribution etc of the rest of the sunlight or rays especially coming from the edges at angle that fall on earth and finally reach our eyes over the course of time which are not constant but changes due to rough surface of sun as you said. Please disregard the earth-sun distance. Anyway, thanks and I appreciate all replies. — Preceding unsigned comment added by Eclectic Eccentric Kamikaze (talk • contribs) 23:30, 8 July 2019 (UTC) For more simplicity, the dark spots (spots from where we don’t receive light rays) on the surface of the sun should increase if we see away from the center of the sun. Since the surface of the sun is not smooth therefore these dark spots should also change their position on the surface of the sun with the passage of time. Similarly, light rays that fall on earth at an angle would nullify shadows either fully or partially due to their cancellation effect. I’m not sure if we are on the same page but this is my thinking, which may be wrong, and again thanks. — Preceding unsigned comment added by Eclectic Eccentric Kamikaze (talk • contribs) 01:21, 9 July 2019 (UTC)

Hi Eclectic. I'm actually not clear on what you are thinking. That's why I suggested drawing a more complete diagram of your thoughts. Words can only convey so much. Someguy1221 (talk) 01:50, 9 July 2019 (UTC)

What darks spots? The sun is extremely bright. Sunspots only look sort of dark because they emit less light than their surroundings. But if you want a clearer idea of what's happening, you could make yourself a pinhole projector like folks often do during eclipses. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:15, 9 July 2019 (UTC)

Like my fellow Wikipedians above, I (speaking as an ex-astronomer) do not find your attempts to describe your thoughts at all clear, but with reference to your last entry you might find the article Limb darkening relevant. I suspect, however, that you have some fundamental misunderstandings about how light behaves, in which case a careful study of the material in at least the opening paragraph of Geometrical optics might help. {The poster formerly known as 87.81.230.195} 2.122.177.55 (talk) 02:22, 10 July 2019 (UTC)

Liquid Glass

I was told by a trained Stain Glass Window maker that during his tutelage he was taught that glass in its natural room temperature state is in fact a liquid. Though this is a little known fact. The reason this was taught to him was that he would need to measure any glass he had created and to in-lay it with the thickest side pointing up once installed. This would allow the glass to flow, though very slowly, over hundreds of years to be thicker at the bottom. If laid the other way around with the thickest side down, the glass would last a much lower amount of time. What truth is there in this please? Is glass at room temperature a liquid, which flows to fill any container it is in, albeit be slowly. In line with this, where is the cut off point for a liquid to be termed and considered a liquid, how long should it take to fill a contain or flow? Like mud, it can be made to fill a container but can also be made to stand on its own. Thanks Anton 81.131.40.58 (talk) 13:42, 8 July 2019 (UTC)

It's not true. "The notion that glass flows to an appreciable extent over extended periods of time is not supported by empirical research or theoretical analysis". Please see Glass#Behavior_of_antique_glass.--Shantavira|^{feed me} 13:53, 8 July 2019 (UTC)

(edit conflict) :Glass is an amorphous solid; the "cathedral glass flow" (liquid glass) theory and contradictory evidence is discussed here: Glass #Behavior of antique glass. However, according to Philip Warren Anderson: "The deepest and most interesting unsolved problem in solid state theory is probably the theory of the nature of glass and the glass transition." —2606:A000:1126:28D:48F3:EC22:BDAE:8519 (talk) 14:09, 8 July 2019 (UTC)

"Liquid glass" is also listed at List of common misconceptions#Materials science. Tigraan^{Click here to contact me} 15:55, 8 July 2019 (UTC)

It is not wrong to consider amorphous solids (including glass) to be liquid-like, since they share traits: Structure of liquids and glasses.

I recommend Viscosity#Amorphous_materials and Viscosity#In_solids. here is an interesting quote

many "solids" (even granite) will flow like liquids, albeit very slowly, even under arbitrarily small stress. Such materials are therefore best described as possessing both elasticity (reaction to deformation) and viscosity (reaction to rate of deformation); that is, being viscoelastic.

Yes, even granite will flow (which will help understand the wonderful fit of old stone wall, btw)

Gem fr (talk) 14:49, 8 July 2019 (UTC)

So will metals. One of the few things that actually behaves like we imagine a solid should behave is a crystal. SinisterLefty (talk) 03:13, 9 July 2019 (UTC)

@SinisterLefty: Please define "crystal", because most metals are crystals (mono- or polycrystals) by the scientific definition of the term (they show a periodic arrangement of atoms at the microscopic scale). Tigraan^{Click here to contact me} 11:54, 9 July 2019 (UTC)

Let's try "single-cell crystals with ionic bonds or covalent bonds (so not metallic bonds)". I may need to refine that further, but I think that's the general idea. It's generally between the cells in multi-celled crystals where the deformation occurs. SinisterLefty (talk) 13:45, 9 July 2019 (UTC)

Just as an aside, back in 2007 a full professor of chemistry lecturing me and the other students in my 3rd year chemistry major cohort regurgitated the "glass is a super cooled liquid at room temperature" line citing the flow of centuries old stained glass windows in cathedrals. I already knew at the time that it was a discredited pop-sci notion. After class I pointed him to the refs on the wikipedia page which explained it was wrong. He steadfastly maintained that it was a fact. This was in a physical chemistry class at a major Australian university. 202.155.85.18 (talk) 01:33, 11 July 2019 (UTC)

Most effective spending on the environment

Are there serious (science-based!) cross-disciplin recommendations about how to most effectively spend money on the environment? Essentially like GiveWell, but for the environment?

I read a few years back in the news that a groups of scientists (?!) was annually (?!) asked how to best spend a considerable amount of money (100 billion??)... but I don't find it anymore. Anything of that sort or related recommendations.

(Obviously any such recommendation would need to seriously debate what they consider "the environment" and what their ultimate goal is - e.g., species protection, combatting global warming, etc. ... but I don't even know where to start looking. All I seem to find are some internet discussions or unsourced gut feelings of well-meaning people. Nothing scientific yet...)

Thanks. Thanks. Thanks for answering (talk) 13:50, 8 July 2019 (UTC)

Please see the work of Professor Bjorn Lomborg You can youtube some of his talks which can be as short as 20 minutes wherre he will cover this topic. Anton 81.131.40.58 (talk) 14:07, 8 July 2019 (UTC)

yes, there are. Lots, actually.

Economically speaking, environment is just a special case of common good (economics) and externality, fields that attracts tons of researchers. Especially when it comes to the so sexy environment. So we have ecological economics, environmental economics, List of environmental economics journals...

Now, as you pointed out, it all depends on the value you bestow to "the environment". An economist can tell you how much it would cost you to do something that the environment take care of (eg: cost of disposing a dead animal, while a vulture will do it for free), that is, price the service of the environment (and some cost if it changes so that it doesn't provide the service anymore); or, the other way round, how much you will benefit from some change (ex: benefits if the Northwest Passage opened). He also can tell you what can be achieved for a given price (eg: what happens if a carbon tax is levied). But he cannot put a price on the existence of a panorama, a swamp, or an insect specie.

So there is no single most effectively spend money on the environment: this will depends on the value the economist uses.

There are, however, lots of least effectively spend money on the environment. Energiewende in Germany for instance (I don't link to our wikipedia article, absolutely unreliable on such highly politicized subject swarmed by militants).

Gem fr (talk) 15:40, 8 July 2019 (UTC)

Re An economist...cannot put a price on the existence of a panorama, a swamp, or an insect specie. Actually he can, by doing carefully worded surveys that ask how much the respondent is willing to pay to keep the panarama etc., and then extrapolating to the whole population and to future generations as well. But of course it's very difficult to elicit responses that are accurate. Loraof (talk) 13:14, 10 July 2019 (UTC)

Looks like to a public worker joke: How do you know if a bridge is to be build over a river? You count the number of people actually swimming across in a year, and multiply by a reasonable estimate of toll and lifetime of the bridge. If the result is more than the cost of building, you do. Gem fr (talk) 17:22, 10 July 2019 (UTC)

Well, you could look at ferry crossings, and what people pay there, but you'd also need to look at people using nearby bridges who would switch to the new one, and perhaps people who opted not to cross the river who would if a local bridge existed. SinisterLefty (talk) 21:31, 10 July 2019 (UTC)

In the case of the swamp, the value is likely negative to those who live there. That is, they are a NIMBY issue. "Lush wetland habitats" sound nice, unless you have to smell swamp gas and battle mosquitoes every day. And finding your dog missing and his leash hanging out of the mouth of an alligator doesn't make locals love swamps much, either. SinisterLefty (talk) 15:33, 10 July 2019 (UTC)

Evidence are that legislations are enacted, and guards paid, so that swamps keep ruining the property, health and life of those living near them, however... So somehow people (most of them NOT living near a swamp, for sure) are very eager to pay for this result. Gem fr (talk) 17:22, 10 July 2019 (UTC)

Coastal swamps do provide environmental benefits, like limiting hurricane damage, so the best solution there is to just ban people from moving there, or, if already there, to provide economic incentives for them to move inland. SinisterLefty (talk) 21:34, 10 July 2019 (UTC)

One thing to be aware of is greenwashing. Spending money on things like "clean coal", for example. SinisterLefty (talk) 03:09, 9 July 2019 (UTC)

I was just thinking I should have mentioned greenwashing (which includes basically ALL that is fashionable and costly, such like renewable energy -- wind, solar --, electric vehicles, recycling, switching back from plastic bottle to glass, etc. Real green is cheap, because it needs as few material, and as few transformation of the material, as possible. Of course all that is cheap is not green; but nothing expensive is). Good that you did Gem fr (talk) 06:40, 9 July 2019 (UTC)

Thanks, but I think most of the items you listed do make sense, at least in some cases. Solar and wind power, for example, make sense where sunlight and wind are strong and consistent, and other sources of power are expensive, such as isolated locations. Electric vehicles could make sense where air pollution is unbearable, like some cities in China. Recycling of lead-acid car batteries makes sense. Glass bottles make sense if you clean and reuse them, like I do.

But, yes, there is a lot of greenwashing, too. Looking at electric vehicles, for example, we have to consider the entire life cycle of the vehicle and batteries, not just "tailpipe emissions". And if electricity in your area comes from burning coal, that's not an improvement over gasoline. I'm also worried that old electric vehicles maybe be junked just because the batteries are weak and replacing them would cost more than the vehicle is worth. SinisterLefty (talk) 07:40, 9 July 2019 (UTC)

Right. Instead of "green", we should talk about "greener". Indeed, in a few case solar and wind are cheaper and greener than, say, coal, but in most case they are not (still; they will eventually, I think), but anyway they never are green. Nothing really is. Gem fr (talk) 10:01, 9 July 2019 (UTC)

To be more specific, my (2 cents worth) understanding of the recommendation are that ... you should just read pigovian tax/pigovian subsidies (and related links) that basically sum up all the issues on the matter Gem fr (talk) 11:23, 9 July 2019 (UTC)

a groups of scientists (?!) was annually (?!) asked how to best spend a considerable amount of money – It sounds like you're thinking of the Copenhagen Consensus. Adrian J. Hunter^{(talk•contribs)} 12:00, 9 July 2019 (UTC)

Scop.

Hello,

I have encountered an abbreviation in Wikipedia for which I cannot locate any definition. I am nearly positive that it must be something basic that everyone knows that I don't! I am referring to a listing for Scientific nomenclature. Please see this entry, https://en.wikipedia.org/wiki/Coryloideae. In the first sentence on the second line you will see, "...extant genera - Corylus L., Ostryopsis Decne., Carpinus L., and Ostrya Scop." What on earth does "Scop." mean? It is not the species. It is not the sub-genus, I don't think. It is a bad abbreviation for "subclade," if that is what it is! I've searched Wikipedia and the general web. Help, please. Thank you. Bjb2466 (talk) 15:16, 8 July 2019 (UTC)

Apparently, it's an abbreviation of Scopoli; see here. Dbfirs 15:26, 8 July 2019 (UTC)

Just as, in the same passage, "L." is an abbreviation of (Carolus) Linnaeus, the Latin form of the surname of Karl Linné, and "Decne." is a similar abbreviation of (the Latin form of?) Joseph Decaisne's surname. In the fullest form of Binomial nomenclature, the name (or a recognised abbreviation thereof) is added to show who first scientifically named and described the species in question. "Scop." indicates Giovanni Antonio Scopoli aka Johannes Antonius Scopolius. {The poster formerly known as 87.81.230.195} 2.122.177.55 (talk) 15:46, 8 July 2019 (UTC)

Is there a Wikipedia article that tells us this stuff? If so, I couldn't find it, and there's nothing useful at Scop.--Shantavira|^{feed me} 08:12, 9 July 2019 (UTC)

Author citation (botany). Mikenorton (talk) 08:48, 9 July 2019 (UTC)

Scop (disambiguation) fixed Gem fr (talk) 09:45, 9 July 2019 (UTC)

Thanks. It's actually all at List of botanists by author abbreviation (It would be a major task to disambiguate all of them. There are a lot!)--Shantavira|^{feed me} 10:14, 9 July 2019 (UTC)

There's also List of authors of names published under the ICZN, which includes all (hopefully) of the above plus biologists. {The poster formerly known as 87.81.230.195} 2.122.177.55 (talk) 17:42, 9 July 2019 (UTC)

I think this task is just impossible. But so was the writing of wikipedia, after all. So, step by step...Gem fr (talk) 10:23, 9 July 2019 (UTC)

July 9

Shear force v Reaction (physics)

• Are shear force and Reaction force the same thing??
• Is hydrostatic pressure a term used to describe the tension force in the water? Do we use hydrostatic pressure when we talk about the tension force of water?

--Exert yourself (talk) 13:29, 9 July 2019 (UTC)

!) No. The reaction to a shear force would be a deformation or fracture.

2) Tension ? No. More like compression force. If you are talking about surface tension, that's unrelated. SinisterLefty (talk) 13:49, 9 July 2019 (UTC)

• • Oh! Thank you so much! I feel I can better distinguish between those. --Exert yourself (talk) 03:33, 10 July 2019 (UTC)

Octonion basis vectors

First, I am relatively new to contributing to wikipedia; so I am not sure if I a going about this correctly, or in the correct location to post.

I was reading the page on Octonions, trying to understand some basics before I take on introdution academic texts. In the definition section it made reference to "non-scalar basis elements". I was not familiar with the phrase or the intent, so I did a google search and found about 50 instances of the phrase. None were clear as to meaning, generally they were used in advanced technical papers on various mathematical topics besides octonions. I then came up with zero hits when combined with "definition". I spent about four hours chasing this.

Going outside wikipedia searching on octonions, I realized the concept being described was just the set of basis unit vectors without the scalar unit vector value "e0" a/k/a/ "1". Just for clarification, I should note that each unit basis vector can be multiplied by a scalar value; so when working with an octonion one has nine numbers that qualify as "scalar".

For clarification I edited the octonion page by adding {{e_{1},e_{2},e_{3},e_{4},e_{5},e_{6},e_{7}}.

The phrase "non-scalar basis elements" is correct, just a little knotty for a newbie. It would also be correct to say "the set of unit basis elements when squared equal negative one".

I just got a message on my watch list saying what I had done was rejected because it was "not constructive", and that I should use sandbox. What I have done is parsimonious and most explicit, and nothing else one could write could be more explicit in describing the matter at hand.

If written explicitly, it would have saved me or someone else, from the loss of time. I am not seeking to have the description "non-scalar basis elements" removed, or adding another knotty explanation included.

Not being an expert on the subject, a newbie must check, double check, and keep checking until competent to prove the concept. In hindsight I would have preferred to have flagged the phrase explaining the confusion, and let someone else improve it.

Not sure how to proceed, or if I should ignore and let it go.

'MatthewDougherty (talk) 19:41, 9 July 2019 (UTC)'

Your edit to octonion still stands (at present), and has not been reverted as "not constructive". The same appears to be true for all your other edits. Perhaps you saw the "not constructive" message on a page history, or on another users contributions list, and mistakenly took it as applying to yourself. So thank you for you contributions and please be bold and continue to edit. catslash (talk) 23:36, 9 July 2019 (UTC)

Must have been a timing issue. I originally saw "not constructive", but when writing this post I went back to the rejection to copy something, and found the rejection missing. Not understanding the mechanics of wikipedia editing, I completed my post and pushed the publish changes on this talk page. Since then, I found the talk section on Octonions, so in future I will restrict these topic specific questions to those talk pages. thx, will keep trying. 'MatthewDougherty (talk) 23:59, 9 July 2019 (UTC)'

Yes, Talk:Octonion is the right place to raise any issues regarding the octonian page - and as there are 111 people watching the page, you are likely to get a response. For pages with fewer watchers, it may be necessary to bring the issue here to get any attention - though this is not the intended function of the reference desk pages. catslash (talk) 00:29, 10 July 2019 (UTC)

July 10

High Frequency Distortion Effect

Does anyone know the name of the strange effect that is observed when I play extremely high notes on a musical synthesizer? Basically, when I play an extremely high note, I get an unusually low frequency distortion noise. Also, when I use the pitch bend wheel, the normal effect is to create a simple change in pitch. However, when I do this with extremely high frequency notes, I get a rather unusual effect, which I can only describe as being similar to the rather cliched "radio tuning" sound effect, that is to say the noise you often hear in cartoons and the like when a radio is being tuned. This effect contains some surprisingly low frequencies, and has a sort of "wob-wob" sound to it.

What is the name of this effect, and why does it happen? I have searched the internet and could not find an answer for this question. do any of you know what it might be?

Could somebody please answer this question. The effect I'm looking for has been bugging me for ages now. It is known to effect frequencies of over 10,000 Hz, with frequencies of over 16,000 Hz being particular prominent in this regard. Please can I have an answer as soon as possible!? Thank you. Pablothepenguin (talk) 23:37, 10 July 2019 (UTC)

---Moved from ent ref desk:

Does anyone know the name of the strange effect that is observed when I play extremely high notes on a musical synthesizer? Basically, when I play an extremely high note, I get an unusually low frequency distortion noise. Also, when I use the pitch bend wheel, the normal effect is to create a simple change in pitch. However, when I do this with extremely high frequency notes, I get a rather unusual effect, which I can only describe as being similar to the rather cliched "radio tuning" sound effect, that is to say the noise you often hear in cartoons and the like when a radio is being tuned. This effect contains some surprisingly low frequencies, and has a sort of "wob-wob" sound to it.

What is the name of this effect, and why does it happen? I have searched the internet and could not find an answer for this question. do any of you know what it might be? 92.19.204.231 (talk) 13:13, 9 July 2019 (UTC).

Could somebody please answer this question. The effect I'm looking for has been bugging me for ages now. It is known to effect frequencies of over 10,000 Hz, with frequencies of over 16,000 Hz being particular prominent in this regard. Please can I have an answer as soon as possible!? Thank you. 92.19.204.231 (talk) 13:01, 10 July 2019 (UTC)

I believe its a form of harmonic distortion/resonance, but can't find appropriate references. Try over at WP:Reference desk/Science, perhaps(?) 2606:A000:1126:28D:84CB:D08E:899F:D254 (talk) 16:30, 10 July 2019 (UTC) — Preceding unsigned comment added by Baseball Bugs (talk • contribs)

One possibility along that line is that what is perceived as a single high frequency note is actually a low note and the high note (and perhaps many in between). According to our article on harmonics: "Most acoustic instruments emit complex tones containing many individual partials (component simple tones or sinusoidal waves), but the untrained human ear typically does not perceive those partials as separate phenomena. Rather, a musical note is perceived as one sound, the quality or timbre of that sound being a result of the relative strengths of the individual partials." So, the synthesizer may be using the same method, only the low frequency notes cause resonance, and are therefore magnified to the point where they are audible and also cause distortion. Although distortion may not be the whole story, as I imagine there's a loose connection and that the low frequency causes it vibrate into and out of contact, making the "tuning the radio" sounds. That's my theory, at any rate. If my theory is right, you may be able to find a loose connection and solder it down or otherwise fix the problem.SinisterLefty (talk) 00:53, 11 July 2019 (UTC)

Assuming that your synthesizer is digital, it could be aliasing. catslash (talk) 00:34, 11 July 2019 (UTC)

July 11

Another cats question.

Okay I already know that mother cats are known to take care of kittens not of their own, including infants of other species. So what if you have 2 female cats, 1 neutered and 1 non-neutered. And they were childhood friends. Then the non-neutered cat gives birth. Say we shortly take the mother away, then will the neutered female cat attempt to look out for the kittens? Obviously she can't milk, but she could at least look out for them in the event of outsiders. 67.175.224.138 (talk) 04:28, 11 July 2019 (UTC). Edit: I wonder if something like this has ever been experimented. 67.175.224.138 (talk) 04:33, 11 July 2019 (UTC).

Even male cats have been observed to spontaneously start caring for random kittens they just met. At least one wild lioness has been observed taking care of juvenile gazelles. I don't know that anyone has attempted a study that could predict this behavior. Someguy1221 (talk) 04:37, 11 July 2019 (UTC)

Being hit by speed of light velocities.

How painful/destructive is it if you were hit by an electron near the speed of light? Then for proton, and cesium atom (the largest non-radioactive atom), and for a water molecule? I heard that if you had something the size of a basketball, made out of nickel, if launched against the Earth can destroy it if it was near the speed of light. Shrugs. 67.175.224.138 (talk) 04:32, 11 July 2019 (UTC).

This question has been answered (more or less) for a baseball, here. --69.159.11.113 (talk) 05:18, 11 July 2019 (UTC)