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January 1

Classic car

Is 20 years supposed to mean or symbolise anything. How do classic cars become 20 years it obviously has to have the historical importance with it but what is 20 years?? — Preceding unsigned comment added by 2001:8003:7427:6B00:B0F5:766D:B6BF:DEBF (talk) 02:28, 1 January 2020 (UTC)[reply]

Your question is not fully clear to me. Maybe you live in an area where being 20 years old allows a car to be classified as a classic car. Perhaps a look at our Classic car article will help clarify things a bit for you. (For starters, the definition varies widely around the world. ) HiLo48 (talk) 02:35, 1 January 2020 (UTC)[reply]

Are you the same user who kept coming here to enquire again and again about what makes classic literature classic? That got old quickly. Matt Deres (talk) 04:01, 1 January 2020 (UTC)[reply]

You mean it got "classic" quickly? --Trovatore (talk) 21:13, 1 January 2020 (UTC) [reply]

It's a rule of thumb. They're going by decades and saying a car generally has to be at least two decades old before it can start to be considered "classic". They're not saying all cars become "classic" the moment they become twenty years old. They presumably judged one decade as being not long enough, and three decades as too long for some examples. --47.146.63.87 (talk) 09:36, 1 January 2020 (UTC)[reply]

Here in Croatia you can request special classic car plates for cars older than 30 years. Other criteria are that you can't drive that car more than X days a week and you need to have other non-classic cars registered in your name and some other stuff. Probably so that people don't apply their crapola they use to commute just to get the discount on insurance and registration. 93.136.45.119 (talk) 19:59, 1 January 2020 (UTC)[reply]

In the UK, the tax people (HMRC) define a classic car as more than 15 years old for "benefit in kind" taxation of company cars. Insurance companies might offer "classic car insurance" on even newer vehicles, depending on type. [1] Alansplodge (talk) 21:54, 1 January 2020 (UTC)[reply]

In California it's 25 years for "classic auto" plates, though you can also order the (ugly) 1960s-style plates for any vehicle. --47.146.63.87 (talk) 10:50, 2 January 2020 (UTC)[reply]

There's two things at play here:

1) The general meaning of "classic" is "kinda old, and kinda well liked" That's about it. It's a very imprecise definition, but it is what people mean in common speech when they say something is "classic".

2) There are legal and other considerations for which an imprecise definition is bad. For example, some state taxation policies may have special taxation rates on "classic" cars. They obviously need to define some time limit on what that agency means by "classic" for their policies. Those definitions are set by those agencies for only that specific purpose, thus times like "20 years" or "25 years" or some such are only defined for the specific purpose they are used for, and not meant to be generally applicable to ANY other situation. For other situations, the imprecise common definition is usually meant.

I hope that helps. --Jayron 32 16:20, 2 January 2020 (UTC)[reply]

There's also the "instant classic." I despise the term, but it refers to something that is instantly a classic because enough people assume that it will certainly be classic once it is old enough. When the PT Cruiser came out, it was referred to as an instant classic because it was unique. Now that it is getting 20 years old, I personally don't know of anyone that considers it a classic car. 168.149.143.112 (talk) 17:36, 2 January 2020 (UTC)[reply]

That's typically marketing hype and means nothing. If the PT was so great, why did they stop making it? Old, of course, is not a ticket to being "classic". I doubt anyone with an ounce of reality would call stuff like the Pinto or the Pacer "classic". ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:19, 2 January 2020 (UTC)[reply]

Is cotton candy flammable?

I have cotton candy and matches, but I'd rather not perform the experiment myself. Temerarius (talk) 20:42, 1 January 2020 (UTC)[reply]

Given that it's nearly pure sugar, a relatively simple carbohydrate which is essentially a hydrocarbon with some oxygen included, and is in a quite finely divided form (see the Sugar article's Subsection Sugar#Flammability and heat response), I'm pretty sure that it is not only flammable, but vigorously so. The fact that our Glucose article has a section entitled "Rocket fuel" is also suggestive. I have never tried the experiment (and indeed have not consumed any of the stuff — known in the UK as Candyfloss – for around half a century), but I'll be astonished if there aren't videos of such an experiment somewhere on Popular Video-sharing sites. Good hunting. {The poster formerly known as 87.81.230.195} 90.204.182.54 (talk) 23:33, 1 January 2020 (UTC)[reply]

In this video the Cotton candy merely melts in a flame. DroneB (talk) 02:30, 2 January 2020 (UTC)[reply]

It's a question of geometry; the more surface area exposed, the more rapidly oxygen can react with the sugar. Various cotton candy mixes may have other ingredients—thickeners, emulsifiers, etc.—which will also affect their properties. As a fine powder, sugar and many other organic substances are dangerously flammable in large amounts; see dust explosion. --47.146.63.87 (talk) 03:56, 2 January 2020 (UTC)[reply]

In the video DroneB links, and others I have now seen, the "cotton candy" used seems somewhat more substantial than the "candyfloss" sort I had envisaged (as shown in the article's infobox). The name seems to cover a range of consistencies, so Temerarius might need to specify which sort they meant.

I note that the melting point of, for example, glucose approaches 150°C, and its heat capacity is nearly 3 times that of water, so getting molten sugar on one's skin is definitely something to be avoided. {The poster formerly known as 87.81.230.195} 90.204.182.54 (talk) 04:29, 2 January 2020 (UTC)[reply]

No, it gloms together instead of outgassing enough to sustain combustion. It will burn if you douse it in alcohol though. EllenCT (talk) 04:11, 2 January 2020 (UTC)[reply]

I used to participate in an educational chemistry magic-show for kids - we did a variation on the theme of the carbon snake that we called "elephant's toothpaste." Our version used sugar and sulfuric acid.

This was a form of rapid-oxidation of sugar (really, the correct term is "dehydration reaction", which is chemically distinct from ordinary burning); but it's highly exothermic and with the right set of circumstances, it could be explosive; and it would surely work with cotton-candy.

All the usual caveats apply: don't try the experiment without appropriate protective equipment, ventilation, training, and so on. Concentrated acid is hazardous for all sorts of reasons. Also be careful of variations on this demonstration that use other chemicals - some release some pretty noxious and deadly toxic gases.

Nimur (talk) 16:42, 2 January 2020 (UTC)[reply]

We also have a Elephant's toothpaste article, but that demo is quite different than the sugar-dehydration concept. DMacks (talk) 00:01, 3 January 2020 (UTC)[reply]

Quite right - we may actually have used the hydrogen peroxide decomposition for "elephant's toothpaste" - I may be mixing up our stage-names and chemical-reactions. The key objective for selecting chemical reactions was to look cool for an audience of seven-year-olds; and a secondary objective was to select reactions that would evoke safe gases that wouldn't interfere harmfully with said audience.

Thanks for the link! Nimur (talk) 16:56, 3 January 2020 (UTC)[reply]

January 6

Gears in gym equipment

The most common weight lifting machines around me just consist of a set of metal plates (can be configured) attached to a cable that go through two pulleys. I know that alternative ways of creating resistance for exercising exist, like pneumatic, elastics, and so on. I suppose these are not as resilient and low on maintenance as a simple block of metal plates with a cable attached. I wonder, couldn't they just make a machine with one weight and a set of gears to add more resistance? I imagine you could also use a level to alter the resistance, but that seem more of clumsy solution. --31.4.128.9 (talk) 08:20, 6 January 2020 (UTC)[reply]

They could, but a possible downside is that people like to know how much weight they are lifting, and the usual arrangement makes that obvious. Alansplodge (talk) 13:59, 6 January 2020 (UTC)[reply]

What's "resistance"? Are you after a large force on a small movement, or a lower force over a long distance? Weights have several advantages: they're simple, reliable and cheap. They also provide a high force, and they provide a constant force. Most spring devices will change force over their travel. It's also easy (with a pin in a stack) to change the force from the same machine, keeping the same overall distance. It's also easy to assemble a weight-based machine, whilst a spring machine might need an assembly jig and carry a risk of finger injury.

For high force devices, most use weights. Some use the operator's own weight - a common design for outdoor park exercise machines is based on lifting the user's own weight, which is usefully self-calibrating for a wide range of users, without needing to adjust anything. These tend to use levers as force adjusters, as the most long-term reliable machine. A few machines use springs or hydraulics, but these are more complicated and have maintenance issues. Elastic (i.e. polymer elastomers) is rarely used (small home-use devices), as it has lifetime issues and a sudden snap is a real problem to design for in a "safe" machine.

For higher forces, a pulley system is more common than gears. It stands up better to wear and exercise equipment is in a very litigious market, where reliability is important. There's sometimes a need to offer a longer movement (some horizontal pulls) and pulleys can do that too - otherwise it's easier to just make more weight go up higher.

For aerobic exercise rather than strength, the load was usually an air fan, a viscous drag or a magnetic eddy current in an aluminium disc. Nowadays though, machines are computer controlled, so active electrical devices (motors) are used, even though they're expensive, complicated and need a power source, just because they're more easily controlled. Andy Dingley (talk) 14:51, 6 January 2020 (UTC)[reply]

A convict in Victorian Britain might find exercise machines crank and treadmill provided for his benefit. DroneB (talk) 16:25, 6 January 2020 (UTC)[reply]

Neither of those were 'exercise' machines. They (deliberately) weren't particularly hard labour, they were mostly boring. Where convicts did actual hard labour (and Dartmoor was one of the few UK prisons where this was the classically hard-working stone-breaking work) they had to be fed better, or else they starved and died. In the typical prisons, the work was tedious but not so energetic, and so the food costs were lower. Andy Dingley (talk) 16:42, 6 January 2020 (UTC)[reply]

Torture and Democracy by Darius Rejali (p. 301) says: 'Nineteenth-century British prisons and reformatories preferred exhaustion exercises. Guards required prisoners to perform shifts on various devices, notably the treadmill (1817) and the crank (1840). As one ascended the wheel, the previous step slid away. It exhausted the strongest of men in fifteen minutes. Turning the crank required turning a handle twenty revolutions a minute, for a total often thousand revolutions in 8.5 hours. “No human being, whether adult or juvenile, could continue to perform such an amount of labour of this kind for several consecutive days, especially on a prison diet, without suffering much and wasting greatly".'

The quote is from Report of the Commissioners Appointed to Inquire Into the Condition and Treatment of the Prisoners Confined in Birmingham Borough Prison, and the Conduct, Management, and Discipline of the Said Prison (1854) p. vii. Alansplodge (talk) 18:02, 6 January 2020 (UTC)[reply]

"Victorian" goes on a long while after that though, and these were falling from use. I think the crank stayed for a long time, but it was specifically punitive (they still have one in Lincoln Castle). Andy Dingley (talk) 18:13, 6 January 2020 (UTC)[reply]

We have both a section of a treadmill, and a crank, in Ripon Prison and Police Museum. --ColinFine (talk) 19:10, 7 January 2020 (UTC)[reply]

Other sources of resistance are flywheels and generators. The latter have the advantage of offering a "reward" such as powering an electric fan. NonmalignedNations (talk) 06:22, 8 January 2020 (UTC)[reply]

Thought experiment: Star with mass in the Brown dwarf mass range with a lot of fissionable elements

Could a brown dwarf with enough Uranium or Potassium 40 shine above its weight class? Perhaps it could do normal hydrogen fusion, instead of deuterium fusion?144.35.45.50 (talk) 23:29, 6 January 2020 (UTC)[reply]

If it performed hydrogen fusion, it would by (current) definition not be a brown dwarf, but a low-mass red dwarf. The two catagories are not strictly segregated by mass (or any other single criterion), and may overlap in characteristics depending which one(s) one chooses to apply. {The poster formerly known as 87.81.230.195} 90.204.182.54 (talk) 23:55, 6 January 2020 (UTC)[reply]

Right, but beyond the question of classification, could such a star exist?Thanks. Rich (talk) 00:43, 7 January 2020 (UTC)[reply]

A natural nuclear reactor could easily exist if the concentration of uranium was high. Of course this is unlikely in a uniformly mixed gaseous body. Perhaps a star formed from binary neutron star merger hypernova output could be highly radioactive and hot, also containing plutonium and thorium. A lot of potassium would also make the body hot. Graeme Bartlett (talk) 03:06, 7 January 2020 (UTC)[reply]

Do you think it would require a fission chain reaction, rather than just many isolated fissions? The fissions here on earth produce a lot of heat.Rich (talk) 04:40, 7 January 2020 (UTC)[reply]

To explain what I meant, suppose a brown dwarf had a mass of 50 Jupiters, and for some bizarre reason, maybe advanced alien tech, that one of those 50 jupiter masses was entirely Pottasium 40. Then isolated disentegrations should provide much much more than just the heat of 32 Earths, because although jupiter is a mass of around 32 earths, fissionable atoms are a small fraction of theearths mass.Rich (talk) 04:51, 7 January 2020 (UTC)[reply]

This could actually make the star a more massive brown dwarf, possibly over the "typical" mass limit for a brown dwarf. A main sequence star is a ball of stuff in hydrostatic equilibrium; its gravity constantly tries to collapse it more, while the fusion in the core generates heat and tries to expand the star, and these two forces maintain a constant tug-of-war as long as there's sufficient fuel in the core. If there's another source of heat, this expands the star as well, opposing the gravitational collapse and therefore reducing the temperature and pressure in the core, possibly below that necessary for the p–p chain. --47.146.63.87 (talk) 07:47, 7 January 2020 (UTC)[reply]

Interesting!Rich (talk) 20:53, 7 January 2020 (UTC)[reply]

(edit conflict) Weight is not really a thing when talking about stars; scientists talk about them in terms of mass, which doesn't vary based on gravitational effects. If a star has enough mass to start the proton–proton chain, it's a red dwarf by definition, as noted above. A star with high metallicity will be denser than a low-metallicity star of the same mass, because the "metals" are denser and thus pack more mass into a smaller volume. This is an example of human intuition short-circuiting. We intuitively think of weight and mass as the same thing, because we think about things in our everyday existence under the influence of Earth's gravity. But stars are ginormous things that gravitate under their own gravitational fields. The primary thing that determines a star's character is its mass, because its mass is what produces its gravitational field. --47.146.63.87 (talk) 04:59, 7 January 2020 (UTC)[reply]

I don’t think any of the posters, including myself, have in any way confused mass with weight. You’ve misunderstood what’s been said.Rich (talk) 07:07, 7 January 2020 (UTC)[reply]

The OP, who 47 replied to did in fact use "weight class" in the question and "mass range" in the heading. I don't know if the OP is actually confused about the difference between weight and mass, but although the term weight is often used to refer to mass in a colloquial sense, I'd agree with 47 that this is one case where it important to appreciate the difference. Nil Einne (talk) 14:38, 7 January 2020 (UTC)[reply]

This is my bad, im the OP. I forgot i used that idiom/sports cliche. “Punching(or shining or performing) out of one’s weight class often does not, now, refer to weight and boxing anymore, for example if a usually poor student outstudies and outscores the class brain on an exam, or if a slow sprinter gets a fast time on the 400 meters due to high anaerobic endurance, it’s said they are performing out of their weight class.Rich (talk) 20:51, 7 January 2020 (UTC)[reply]

January 7

relation of human-fungi for antibiotics

In biology, we have many types of relations between two organisms and more (i.g. commensalism, symbiosis etc.). My question is what's called the relation / way of people to take or produce antibiotics by fungi? 93.126.116.89 (talk) 00:11, 7 January 2020 (UTC)[reply]

It is called Medicinal fungi and Wikipedia has an article about it. --Jayron 32 12:07, 7 January 2020 (UTC)[reply]

Thank you for your comment, but it isn't my question:). I asked about the relation (I gave a couple of examples for relations in biology: commensalism, symbiosis). 93.126.116.89 (talk) 21:17, 7 January 2020 (UTC)[reply]

Typically the fungus is destroyed in the process of consuming it. You would call it mycophagy. A non-human animal that consumes another organism for medicinal purpose could be said to be engaging in zoopharmacognosy. Someguy1221 (talk) 21:57, 7 January 2020 (UTC)[reply]

January 8

Which of "geometric algebra" or "algebraic geometry" proceeds the other.

Wow! sushi (talk) 05:08, 8 January 2020 (UTC)[reply]

(we don't have so much time...) _ I need to confess , I am multi-personalities.

Wow! sushi (talk) 05:12, 8 January 2020 (UTC)[reply]

Geometric algebra#History 1844

Algebraic geometry#History 16th Century? Graeme Bartlett (talk) 05:50, 8 January 2020 (UTC)[reply]

Insect identification

Hello, What is this insect called? I found it in Mizoram, India. There are shells on the body and the trail illuminates in the dark.

Unknown Insect
Image 2

Sandeshkumar M. 11:19, 8 January 2020 (UTC)

Are you sure this is an insect? Check the underside for number of legs. It has the same number of segments as a woodlouse. Graeme Bartlett (talk) 09:50, 8 January 2020 (UTC)[reply]

I don't really know what it is. An insect or something else. I've uploaded another image of the creature.

Sandeshkumar M. 11:28, 8 January 2020 (UTC) (talk)

To help accurate identification include -

Something to show scale: ideally that would be a ruler with millimetre graduations. A picture of the bottom of the organism. A white background for the picture - it helps to give a better idea of the colour of the organism. A picture of the bioluminescence - this would be in an ideal world. A picture of the place you found it - to give an idea of habitat. A general name like Mizoram is useful - it narrows things down. But was it in woodland or human settlement. I appreciate this is a lot of information, but accurate identification is aided by this kind of information. There are places in India where bioluminescence is common. For Mizoram, that seems to be plant based rather than animal so more information about the animal is really needed to identify it correctly.

Having said that: it does look quite like a woodlice (and definitely an isopod). But I only counted eleven obvious segments - there could be 14 which is indicative of a woodlouse - a picture of the rear end from above would help to clarify that. There appear to only be three pairs of legs - woodlouse have seven pairs of legs (they can vary in size, so only seeing three pairs might mean the others are hidden). — Preceding unsigned comment added by Hongnang (talk • contribs) 12:55, 8 January 2020 (UTC)[reply]

Human Predation

When a predator is removed from the food chain it is often seen that there is an overpopulation of another species. The most well-known example I can think of at present (which is not the same) is the Cane Toad in Australia, where without a predator, they have bread to enormous population sizes causing widespread destruction. Further to this, if predation on a species takes place the food item tends to populate to make up for the loss and similarly if a food source reduces the number of predators reduces too. To expand on this concept, if my reserve has 10,000 impala and I have 100 lions, (10:10,000)… if the lions eat 2,000 impala, the impala will generally have about 2,000 offspring during the next breading cycle, and the numbers (presuming they are evenly matched, lions to impala and assuming there are no other animals [work with me here people]) In the same manner, if I hunt 9,000 of my impala, my lions will die off until I have only 10 (1,000:10). Nature ensures there is an equilibrium, if all of the additional environmental factors are left in situ and allowed to run their course. What has been removed from the ecological chain to allow for the human race to overpopulate to such a degree as to cause the now seen climatic chaos. How was this element removed? Thanks. Anton 81.131.40.58 (talk) 15:56, 8 January 2020 (UTC)[reply]

@@ Line 126: / Line 126: @@
 Having said that: it does look quite like a woodlice (and definitely an isopod). But I only counted eleven obvious segments - there could be 14 which is indicative of a woodlouse - a picture of the rear end from above would help to clarify that. There appear to only be three pairs of legs - woodlouse have seven pairs of legs (they can vary in size, so only seeing three pairs might mean the others are hidden).  <!-- Template:Unsigned --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Hongnang|Hongnang]] ([[User talk:Hongnang#top|talk]] • [[Special:Contributions/Hongnang|contribs]]) 12:55, 8 January 2020 (UTC)</small> <!--Autosigned by SineBot-->
+== Human Predation ==
+When a predator is removed from the food chain it is often seen that there is an overpopulation of another species.  The most well-known example I can think of at present (which is not the same) is the [[Cane Toad]] in [[Australia]], where without a predator, they have bread to enormous population sizes causing widespread destruction.
+Further to this, if predation on a species takes place the food item tends to populate to make up for the loss and similarly if a food source reduces the number of predators reduces too.  To expand on this concept, if my reserve has 10,000 impala and I have 100 lions, (10:10,000)… if the lions eat 2,000 impala, the impala will generally have about 2,000 offspring during the next breading cycle, and the numbers (presuming they are evenly matched, lions to impala and assuming there are no other animals [work with me here people]) In the same manner, if I hunt 9,000 of my impala, my lions will die off until I have only 10 (1,000:10).  Nature ensures there is an equilibrium, if all of the additional environmental factors are left in situ and allowed to run their course.
+What has been removed from the ecological chain to allow for the human race to overpopulate to such a degree as to cause the now seen climatic chaos.  How was this element removed? Thanks. Anton [[Special:Contributions/81.131.40.58|81.131.40.58]] ([[User talk:81.131.40.58|talk]]) 15:56, 8 January 2020 (UTC)