Wikipedia:Reference desk/Science

Welcome to the science section
of the Wikipedia reference desk.

skip to bottom

Select a section:

• Computing
• Entertainment
• Humanities
• Language
• Mathematics
• Science
• Miscellaneous
• Archives

Want a faster answer?

Main page: Help searching Wikipedia

   

How can I get my question answered?

• Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
• Post your question to only one section, providing a short header that gives the topic of your question.
• Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
• Don't post personal contact information – it will be removed. Any answers will be provided here.
• Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
• Note:
  • 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.
  • We don't do your homework for you, though we'll help you past the stuck point.
  • We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

• The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

See also:

• Teahouse
• Help desk
• Village pump
• Help manual

July 1

Time to space in Gemini 8

I was watching First Man and noticed that the sequences from liftoff of Gemini 8 to reaching space (or orbit, I don't remember) lasted a few minutes, they seemed as if intending to represent real time. The Gemini 8 article has March 16, 1966, 16:41:02 UTC as launch time and March 16, 1966, 22:14 UTC for the docking with Agena. But I don't see the time for reaching the space (or orbit). Do space flights usually take just some minutes to reach space?

Launch and Early Orbit phase is very small. Space launch says:

the edge of space is defined by convention, often the Kármán line of 100 km. Other definitions have been created as well, in the US for example space has been defined as 50 miles.

I do not have a preference for a definition. Anything that works in a movie to establish "the ship reaches space" is enough for me. It also says:

It is not generally recognized by the public that the increase in potential energy required to pass the Kármán line is only about 3% of the orbital energy (potential plus kinetic energy) required by the lowest possible Earth orbit (a circular orbit just above the Kármán line.) In other words, it is far easier to reach space than to stay there

--Error (talk) 00:19, 1 July 2019 (UTC)

Orbital objects are going some 17,000 mph in LEO. While they are not going that fast earlier in flight, they are still booking. Depending on your definition of the boundary of space and your launch vehicle, it only takes a couple minutes to reach space. Kees08 (Talk) 01:07, 1 July 2019 (UTC)

Reaching space (using whatever definition of space) usually isn't very interesting. It's about reaching orbit, which is when the engines are shut off and (apparent) microgravity begins. On some launches there may be a half-orbit coast phase followed by a few seconds circularization burn. From launch to orbital insertion last somewhere between 8 and 15 minutes on most launches.

The Titan II GLV used in Project Gemini had a rather high acceleration (up to about 6g, according to our article), so it reached orbit quickly. Our article mentions 156 seconds first stage and 180 seconds second stage burn, indicating it reached orbit in slightly less than 6 minutes. PiusImpavidus (talk) 08:42, 1 July 2019 (UTC)

(edit conflict)Depends if the vehicle is manned or not. If not, like a Minuteman, around 3 minutes are needed. But this require too much acceleration for a human being, so it takes ~3x more time, for instance, for Space_Shuttle to reach orbit. This is still less than 10 minutes. Gem fr (talk) 08:45, 1 July 2019 (UTC)

To see how long it takes to reach space (as defined however you would like to define it yourself), you can watch an old live stream of a SpaceX launch on youtube such as this one. 139.194.66.147 (talk) 11:19, 1 July 2019 (UTC)

In the case of STP-2, at T+00:03:13 the vehicle reached an altitude of 100km. At T+00:08:27 it reached a speed equal to LEO velocity. So the answer to whether space flights usually take just some minutes to reach space, yes, space is reached within minutes. 139.194.66.147 (talk) 12:49, 1 July 2019 (UTC)

Thank you all. Your answers satisfied my curiosity. --Error (talk) 23:01, 1 July 2019 (UTC)

Oddly enough, there was a comedy movie once where this bit of rocket science formed a plot point. In The Mouse on the Moon (1963), the spaceship from Grand Fenwick takes off slowly and intends to take weeks to get to the Moon. And Prof. Kokintz explains that they have no need to hurry because they have plenty of energy available from their special fuel. (That's not a direct quotation, but it's the essence of his point.) Real-life rockets generally accelerate rapidly to their final speed because fuel burned for any purpose other than accelerating the payload is essentially wasted, and if there is fuel available to waste, more fuel is spent accelerating it. This all ties in with the Tsiolkovsky rocket equation. --76.69.117.113 (talk) 06:15, 2 July 2019 (UTC)

A wonderful reference is NASA publication SP-4203: On The Shoulders of Titans: A History of Project Gemini, a zero-cost full-length book available from NASA's history website.

On Page 199 there is a brief accounting of times for Gemini 1 (also called Gemini-Titan 1):

“ Two and a half minutes after liftoff, the 118 tonnes (130 tons) of propellants in its first stage exhausted after driving Gemini-Titan 1 64 kilometers high and 91 kilometers downrange, GLV-l's first-stage engines cut off. The sec­ond-stage engine flared into life, and the four bolts that had held the two stages together exploded as they were designed to, cutting the spent first stage loose from the still-accelerating second stage and spacecraft. Five and a half minutes after launch, the second-stage mo­tor stopped, its 27 tonnes (30 tons) of propellants gone. Now 1000 kil­ometers downrange and 160 kilometers high, coasting at a speed of 7888 meters (25 879 feet) per second, Gemini Spacecraft 1, with the second stage of GLV-1 still attached, was in orbit. ” — Barton C. Hacker & James M. Grimwood, NASA SP-4203

A similar accounting is provided for each launch. For example, Gemini VIII - as the original question posed - is described around pg. 309 and of course involves two different types of rocket with two distinct launch timelines. Bear in mind that there was a "time-to-orbit" for each spacecraft, and then a time to the "correct" orbit (for rendezvous) which occurred a few hours (several orbits) later.

Similar details are provided, e.g., for Gemini IX-A, pg. 332, and so on; and culminating with Gemini XII, pg. 374, in which a NORDO radio problem meant that certain exact technical details in the early-phase-of-flight are probably lost to history.

This is a great book, and was informed by interviews with astronauts, engineers, flight specialists, and senior program officials; it also has reference appendices with short data summaries for the interested readers.

Cited by this resource are many dozen more technical publications, including of course NASA SP-4002 Project Gemini: Technology and Operations (1969), which contains the wonderful Appendix 1, Table B: Gemini Program Flight Summary Data - Orbital Operations (and similar tables), in case you're planning a mission and need to pop these into your favorite ephemeris calculator.

Nimur (talk) 14:56, 2 July 2019 (UTC)

Just a science question if there's an official record

Hi all, is there an official source stating the weight of Kim? I read articles about him having problems with one of his legs and guessed this. Is that information available? Thanks all. --LLcentury (talk) 02:39, 1 July 2019 (UTC)

Kim who?--Shantavira|^{feed me} 05:53, 1 July 2019 (UTC)

I suspect the OP probably means Kim Jong-un. I doubt there is any reliable official source because the North Korean government generally just makes up whatever they feel suits. I mean the situation in North Korea is nuts enough that it's hard to know whether even Kim knows his weight, or his doctors have a proper record of it or they were afraid of annoying him in some way and so use a purposely miscalibrated scale or whatever. Kim has traveled to various places but recording the weight of leaders visiting your country isn't something countries tend to do at least officially. (I mean theoretically the Russians, Chinese, Singaporeans, Vietnamese etc could have hidden scales in stuff he stood on, but they're not going to tell us what they learnt.) According to [1] South Korean intelligence have actually tried to track his health including weight from video footage and estimated it was 130kg at one time but I'm doubtful that sort of thing is any more accurate to within 20% or so, and probably less. Nil Einne (talk) 08:20, 1 July 2019 (UTC)

I suppose rapid weight loss could be a sign of serious illness, and since him dying and leaving NK's nukes in the hands of somebody potentially even more crazy than him would have serious implications, I wouldn't put it past a security agency to put strain gauges under the floor of a hallway he was to walk down during a visit, to measure his weight as accurately as possible. Of course, they wouldn't publicize this fact, nor the results. SinisterLefty (talk) 12:55, 1 July 2019 (UTC)

Yes, my apologies, I was referring to Kim Jong-un. - --LLcentury (talk) 10:38, 1 July 2019 (UTC)

If Trump's weight is known, someone could probably do an estimate of Kim's from their side-by-side photos. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:46, 2 July 2019 (UTC)

Trump is a lightweight, being mostly hot air and inflated ego, with nary a fact to weigh him down. SinisterLefty (talk) 17:47, 5 July 2019 (UTC)

Ref Desk is not the place to seek medical advice, so expressing here a Trump derangement syndrome wont help you. However, psychological projection is certainly a place to start. Gem fr (talk) 07:27, 6 July 2019 (UTC)

Crossing Over in Genetics

I'm trying to teach myself the basics of genetics. One very basic question that I'm not clear on is whether (let's limit to humans for simplicity) genetic diversity is always a matter of combination of individual chromosomes or whether alleles from different chromosomes can be mixed together. E.g., suppose we have chromosome C1 and the Father's genome is C1F1 and C1F2 and the mothers C1M1 and C1M2. My understanding is that in Meiosis we get four haploid daughter cells with the values for C1 being: C1F1, C1F2, C1M1, and C1M2 and that the new fertilized egg will have one of these from the father and one from the mother. However, it also seems there is something called Crossing Over where alleles from one chromosome get swapped with the homologous (I think that's the correct term) alleles from another. So that the child could end up with a C1 chromosome that was a combination of say C1M1 and C1F1. I hope my question is clear and I'm not butchering the terminology. Also, just to be clear, I'm aware there are also other factors that are very important such as epigenetics, the environment in the womb, etc. but I'm just trying to make sure my basic understanding of Meiosis in humans is correct. Thanks for any help. --MadScientistX11 (talk) 22:25, 1 July 2019 (UTC)

You have it correct. This is diagrammed in the image at the top of Meiosis, for a hypothetical organism with two chromosome pairs. For ease, in that diagram the paternal and maternal chromosomes are different colors. As you can see, the gametes that come out of meiosis have one full copy of each chromosome, but it is a mix of red sections and blue-grey sections. In that diagram, as is actually very typical, crossing over only happened on one member of each pair of sister chromatids. However, that is not actually a rule. It could happen by chance, but both sister chromatids can experience crossing over. Someguy1221 (talk) 22:52, 1 July 2019 (UTC)

did you read chromosome allele Chromosomal crossover Unequal crossing over ?

Gem fr (talk) 23:02, 1 July 2019 (UTC)

Thanks. I read the Chromosomal crossover article but not the others, I'll take a look at them. Part of the reason I was confused is that a professor told me the opposite, but she was not a biology professor and she was teaching genetics as one part of a larger class. And it's such an important concept (it really increases the combinatorics of possible genotypes) that I wanted to make certain I was understanding it correctly. Thanks a lot for the quick response. --MadScientistX11 (talk) 03:09, 2 July 2019 (UTC)

What do you mean, she told you the opposite? What specifically was she talking about, do you remember? I might know what she meant. Someguy1221 (talk) 04:28, 2 July 2019 (UTC)

July 2

Anyone else's parrot ever do this?

My pet parrot sits at the window, watching the world go by most days.

Whenever she sees a hawk, or a crow/magpie, or a big seagull flying over, she starts squawking and getting agitated, while looking back and forth between me and the other bird, as though to say "follow my eyes".

Is she watching my back for me? Showing me that there's a scary bird that might come after me? Or maybe she'd like me to go out and scare it away? Am I reading that right? Pretty cool. — Preceding unsigned comment added by 146.200.133.209 (talk) 09:53, 2 July 2019 (UTC)

Parrot#Intelligence_and_learning Parrot#Cooperation Parrot#Relationship with humans Companion parrot etc. Gem fr (talk) 10:58, 2 July 2019 (UTC)

I'd say it's instinct at work. They instinctively warn others when a potential threat is identified, which involves calling and watching members of their flock, to ensure that they are reacting accordingly. Presumably a lack of reaction would get them to make even more noise, while if every bird in the flock takes cover, they would go silent and take cover, too. (Although a smaller bird that they can take on, and is only a threat to eggs/chicks, would call for a swarm attack.) SinisterLefty (talk) 11:16, 2 July 2019 (UTC)

This is recognised behaviour among Australian parrots, to the extent that it became a part of Australian English. See the description of the role of the Cockatoo at a game of Two-up as the person who warned players of the game of police raids in the days when it was illegal. HiLo48 (talk) 11:27, 2 July 2019 (UTC)

My parrot is a goffin, so quite closely related to Australian parrots. — Preceding unsigned comment added by 146.200.133.209 (talk) 19:44, 2 July 2019 (UTC)

July 3

Solubility of sugar(s) in sodium /alkali metal halides

What data are available for solubilities of sucrose in solutions of sodium chloride and other alkali metal halides of various concentrations of these salts included saturated ones? (Thanks!) --109.166.139.165 (talk) 15:02, 3 July 2019 (UTC)

A similar question for glucose and fructose! --109.166.139.165 (talk) 15:05, 3 July 2019 (UTC)

The general concept of reducing the solubility of an organic molecule through the addition of salt is known as salting out. This is normally described for precipitating large molecules like DNA or protein, though it can be done for much smaller molecules as well. However, I have not seen any literature describing salting-out conditions for simple sugars. Someguy1221 (talk) 01:42, 4 July 2019 (UTC)

Found a ref:

• Young, R. A. (1898). "The Precipitation of Carbohydrates by Neutral Salts". 22 (5): 401–422. doi:10.1113/jphysiol.1898.sp000703. {{cite journal}}: Cite journal requires |journal= (help)

that reports an "extended investigation of the action of neutral salts on carbohydrate solutions". Among its conclusions is that "ordinary crystalline carbohydrates, dextrose, laevulose, cane sugar, maltose, and lactose were all investigated, but as was expected with uniformly negative results as far as precipitation was concerned." It does report that some other types of carbohydrates can be salted out. Interestingly, it also notes that the crystalline carbohydrates form complexes with some salts, and that most of these complexes are crystalline. For example, I was surprised to learn that sucrose·NaCl·H₂O is a known substance since the late 1800s! If the carb complexes with the salt, I'm not surprised that it's not going to lead to precipitation of the carb itself. DMacks (talk) 02:40, 4 July 2019 (UTC)

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: [2]. 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: [3]. 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: [4]. 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 - [5]. 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: [6] DroneB (talk) 23:49, 6 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)

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 [7] 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 [8]. 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 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)

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)

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)

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)

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. "Scopoli" 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)