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April 6

Extraterrestrial government and economy

Has anyone ever speculated what types of governments and economies extraterrestrials might have?Uncle dan is home (talk) 00:30, 6 April 2017 (UTC)

If you count sci-fiction, then definitely, lots of authors. --Hofhof (talk) 01:08, 6 April 2017 (UTC)

Yes in 1000s and 1000s of Science Fiction books, short stories, films and various other media. This is still one of my favorites. MarnetteD|Talk 01:10, 6 April 2017 (UTC)

Foundation (Isaac Asimov novel) is a classic. Blooteuth (talk) 12:55, 6 April 2017 (UTC)

Asimov also wrote several non-fiction works speculating about alien civilizations; although these were more heavily concerned with planetary science, physics in general, and speculative engineering, there is some intermitent discussion of how the societies themselves might be organized. Snow ^{let's rap} 09:06, 7 April 2017 (UTC)

Could a natural breast look like fake?

This discussion is closed. Blooteuth (talk) 23:47, 8 April 2017 (UTC)
The following discussion has been closed. Please do not modify it.
In the same way that fake boobs sometimes look natural, could the contrary happen, and perfectly natural boobs look as if they were fake? Like being too round?--Dikipewia (talk) 03:06, 6 April 2017 (UTC) Are you the one that asked about unwanted touching? ←Baseball Bugs What's up, Doc? carrots→ 05:39, 6 April 2017 (UTC) Please refer to the page header: "We don't answer requests for opinions, predictions or debate." --47.138.161.183 (talk) 07:20, 6 April 2017 (UTC) Unless there's some health issue behind it (like tumors making it look swollen, or a hormone unbalance), no. Why would they? But there are thousand different forms that a breast can have. Natural breasts will always be fuller on the bottom, contrary to implants which are basically a filled bag (or silicone or saline). --Hofhof (talk) 11:47, 6 April 2017 (UTC) We definitely should upgrade our resources on fake breast detection. My suspicion is that seismology is a main discipline of relevance here, though of course a hands-on measurement of the deformation (engineering) is the gold standard. I'm prone to suspect that when you see a very slight wave jiggle up through a breast each time a woman's foot clacks against the floor, that this is evidence of a natural breast, while interference with these waves might indicate the potential presence of a heterogeneous core. But I'm not sure this is actually valid (never took my proposal to go asking significant numbers of women whether those boobs are real before the institutional review board) let alone whether something like fibrocystic breast changes would foul up the measurement. (On the other side we should check whether canny implant manufacturers do effective impedance matching) Of course, even fake breasts tend to occur with real women attached, and so this may not be a factor of overriding importance. ;) Wnt (talk) 16:31, 6 April 2017 (UTC) This is getting offensive. WP:DENY. The IP had this right; we don't get into discussions predicated on opinion here--not any topic and certainly not regarding the "natural" or "fake" contours of a woman's breasts. Even giving the OP the largest possible benefit of the doubt as to sincerity of their interests (vs. trolling/juvenile attempts at titillation), this discussion still (predictably) took zero time to reach unacceptable comments. On that topic, I would like to say--for the benefit of any contributor, but one in particular--that if you ever find yourself on the verge of writing the words "breast" and "jiggle" in the same sentence anywhere on this project, stop and take stock of where you are and what you are doing. I don't care if you are genuine about your speculation or, alternatively, how tongue-in-cheek clever you think you are being in responding as you are--stop and think about whether that particular sentence can ever be seen as useful to the building of an encyclopedia, and the kind of uncomfortable atmosphere it creates for female contributors. Seriously, I very nearly took this to an admin, and won't hesitate next time. Just not appropriate for this project. Snow let's rap 10:05, 7 April 2017 (UTC) }}

Equilibrium question - Physics

A point body in static equilibrium will remain at rest or continue moving with a constant velocity. This means net force on a point mass is zero if moving with constant velocity in space. Thus does the equilibrium status of a point mass moving with constant velocity alter if brought to rest with the help of external force? Unbalanced force(s) change the equilibrium status of a body, therefore, is the aforementioned external force on a point mass, which changes its position to stationary unbalance?2001:56A:7399:1200:7436:C9CB:D58F:2D2A (talk) 05:01, 6 April 2017 (UTC)eek

Yes. While the object is moving with constant velocity it is in equilibrium. While it is slowing down it is not in equilibrium, therefore there must be some net unbalanced force acting on it. Once it is at rest (which is a special case of constant velocity) then it is in equilibrium again. Gandalf61 (talk) 07:44, 6 April 2017 (UTC)

Yes. While the body is slowing down, Newton's 2nd Law explains that the force F on the body is equal to the mass m of the body multiplied by the deceleration i.e. "negative acceleration" a of the body: F = ma. If the decelerating force is applied by contact with a second body, Newton's 3rd Law indicates another balance of forces thus: "When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body". Blooteuth (talk) 12:51, 6 April 2017 (UTC)

It's still not clear to me – if the forces are already balanced on an object moving with constant velocity then why would it require an external force to make forces balanced again. Does this mean forces were not balanced when the object was moving constant velocity? isn't aforesaid external force balancing opposing force which is in the form of constant velocity and mass? Just ask another question (may be nonsense) - would the said mass carry on again with its previous constant velocity (in the form of conserved force) from rest position If the resistive external force is removed — Preceding unsigned comment added by 2001:56A:7399:1200:504C:D5D1:AC3C:2E62 (talk) 04:47, 7 April 2017 (UTC)

• If the forces are balanced, the object moves with constant velocity (assuming an inertial reference frame). "Constant velocity and mass" are not forces.

What could happen though is that as the object moves the forces change. I suspect you might be mixing up two meanings of equilibrium: "forces are at equilibrium" meaning the forces cancel each one out, and "equilibrium point" = a location where the potential energy curve as a function of position is flat. Tigraan^{Click here to contact me} 10:55, 7 April 2017 (UTC)

At rest, forces on an object are balanced in all direction in space. An object starts moving in the direction of net greater force when an external force is applied. It is said an object attains its constant velocity when an external force is removed. Although the external force is removed but it already made the forces on object unbalanced resulting in the constant velocity of an object in the opposite direction of the weaker force on an object. However, if this is not true then IMPOV – An object would attain its rest position again instead of moving with constant velocity when an unbalanced external force is removed. Since all forces balanced again on the object when an unbalanced external force is removed therefore it can’t move in any direction, as movement requires unbalance force.

This is my personal thinking (freedom of expression), however, I appreciate all replies. Thank you all. — Preceding unsigned comment added by 2001:56A:7399:1200:A5F2:D507:5BDD:E264 (talk) 05:19, 8 April 2017 (UTC)

You do not seem to have understood that Newton's Laws describe a single point mass and a single external force. That force may an isolated force or it may be the resultant (or nett force) of several forces, but that makes no difference to the object. At rest the force is simply zero i.e. absent. While a force is being applied, the object accelerates. When that force is removed, the object continues moving at the velocity imparted to it, and that is the only trace of what was done. That goes on notionally forever, there is no other "memory" of "unbalanced forces", nor does its movement now require any force to maintain it. This is elementary Classical mechanics that indicates your view that "An object would attain its rest position again...when an unbalanced external force is removed" is wrong, regardless of any claimed "freedom of expression". Blooteuth (talk) 23:38, 8 April 2017 (UTC)

What is the difference between the cells of the electrical conduction system to the rest heart muscle cells?

According to the article here "The conduction system consists of specialised heart muscle cells, and is situated within the myocardium. There is a skeleton of fibrous tissue that surrounds the conduction system which can be seen on an ECG. Dysfunction of the conduction system can cause irregular, fast, or slow heart rhythms.". In what they unique compared to the rest muscle cells? according to other articles here the muscle cells of the heart (no differentiation) has the feature of automatically. 93.126.88.30 (talk) 06:16, 6 April 2017 (UTC)

The article referred is Electrical conduction system of the heart. Another article describes the heart muscle which differs from skeletal and smooth muscle. An automatic (spontaneous natural pacemaker) pulse arises from the Sinoatrial node and is conducted via Bachmann's bundle from right to left atrium. The AV node introduces a delay of about 0.12s which ensures that the atria have ejected their blood into the ventricles first before the ventricles contract; this delay is seen as the PR segment on the EEG. Blooteuth (talk) 12:34, 6 April 2017 (UTC)

Thank you for your comment. But I'm sorry I didn't understand the answer to my question. It's used to be said that there is electrical conduction system of the heart which conducts the electricity to the muscle, and from that I understand that these cells are not muscles by themselves they just conduct the electricity. Isn't it? 93.126.88.30 (talk) 15:03, 6 April 2017 (UTC)

The cells in question are Purkinje fibers. They are usually considered to be a special type of muscle cell. Their signal-conducting role arises ultimately from the fact that, although all heart muscle cells are spontaneously rhythmic, the cells of the sino-atrial node beat a little bit faster than cells in other parts of the heart. Consequently on each heartbeat they are the first cells to start firing. The Purkinje fiber system conducts their activity rapidly to other parts of the heart, ensuring that each part fires as a synchronized whole at the proper time. Looie496 (talk) 15:34, 6 April 2017 (UTC)

Tetrapod Clades that Survived the K/T Boundary?

Is there any source that describes which tetrapod clades survived the KT event? For example, was there only one turtle that was the ancestor of all turtles alive today? Or are the sideneck turtles a separate branch since before the KT event? As for the birds, my understanding is that Presbyornis, a galloanser, shows that clade predated and survived Chicxulub. Thanks! μηδείς (talk) 17:43, 6 April 2017 (UTC)

There is a lot of information in the article Cretaceous–Paleogene extinction event - and also a lot of references. Just checking turtles it actually says "Over 80% of Cretaceous turtle species passed through the K–Pg boundary. Additionally, all six turtle families in existence at the end of the Cretaceous survived into the Paleogene and are represented by living species." Read the article for information about other groups of animals. Wymspen (talk) 18:11, 6 April 2017 (UTC)

Thanks, @Wymspen: the six still-extant turtle families is exactly what I was looking for. Thanks for the link. I am most interested in mammals and birds. For example, are the Afrotheres pre- or post-K? μηδείς (talk) 21:45, 6 April 2017 (UTC)

You just need to keep reading and follow the links. The Afrothere article includes a line saying that the oldest know fossil is Ocepeia and that article says it dates to about 60 million years ago. As the Cretaceous–Paleogene extinction event is dates at 66 million, that makes it more recent. Inevitably, you have to accept that there may be older species for which there is (as yet) no fossil record. Wymspen (talk) 22:19, 6 April 2017 (UTC)

These are largely unsettled questions. Geographic distributions suggest that the splits between afrotheria, xenarthra, laurasiatheria and euarchontoglires resulted from the breakup of Pangaea, which happened many millions of years before the KT event. Looie496 (talk) 01:21, 7 April 2017 (UTC)

Are longer focal distance magnifiers more expensive to manufacture?

There are worn magnifiers (in the form of loupes or similar) quite cheaply available for people to use when working with electronics or sewing or painting figurines etc but for some reason they all have a very short focal length so you have to be very close to the workpiece which is sometimes very impractical, especially with soldering. If you look at reviews there are often many complaints about this problem. There are some magnifying loupes available with focal distances of around 300-400 mm which is more practical but they're all extremely expensive. Is it more difficult to make lenses with a longer focal distance or what?

It would be easy to make such lenses in a simple form, but a big problem could be that the combination of their magnification and the longer distance to the objects would likely lead to (a) rather restricted fields of view and (b) the restricted image dancing around annoyingly. It might be possible to overcome this with more elaborate compound lenses, but these would be more expensive than a simple lens, and would also be heavier and more cumbersome to wear. An alternative might be to use a lens (or lens combination) held on a fixed (though adjustable) stand between the eye and the work material, rather than wearing it. I'm not sure of the term of art for such a setup, but I have seen it in use. {The poster formerly known as 87.81.230.195} 90.217.249.244 (talk) 12:29, 7 April 2017 (UTC)

The OP is right in part. But it is the depth of field that matters too. For fine soldering I found that OptiVisor Headband Magnifiers makes life easy. Just google.--Aspro (talk) 13:16, 7 April 2017 (UTC)

View: How to Choose the Right Optivisor Headband Magnifier. There are many other cheaper copies available but one gets what one pays for. The plastic becomes brittle and brakes and the adjustment clamps fail with little use, etc. --Aspro (talk) 14:09, 7 April 2017 (UTC)

The OptiVisor's 3.5x focal distance is only four lousy inches (12 cm). Other more expensive lenses are like 32-40 cm. ----Seans Potato Business 23:55, 7 April 2017 (UTC)

Is there any danger of the world running out of oil or does other energy advancements make that unlikely?

2.102.184.154 (talk) 21:50, 6 April 2017 (UTC)

Our article is Peak oil. However, since 2014 the world has an excess of oil production, due in large part to fracking in the US. This has driven the price of crude oil down from >$100/bbl to <$50/bbl. In addition, the costs of solar and wind are rapidly decreasing, which is apparently reducing oil demand. As with most commodities, we don't "run out". instead, as the cost increases, the commodity quits being used for those uses that have cheaper alternatives. In this sense, we will never run out of oil, we will just quit using it to make gasoline for cars. -Arch dude (talk) 22:05, 6 April 2017 (UTC)

One reason for not running out of oil is that people change the definition. Once oil was whale oil and petroleum was just a contaminant in salt wells. Later on, shale oil wasn't really "oil". Biodiesel isn't quite "oil" in modern speech, but it might soon become such. Even among petroleum there are various types and grades, not all of which were all that usable in the past. There is, of course, only a limited amount of hydrocarbon in the Earth's crust, and an even more limited tolerance of the atmosphere and ocean for absorbing CO2, but it's fair to suppose that people will try to make do; modern energy technology gives a fair range of options. Wnt (talk) 01:46, 7 April 2017 (UTC)

• Known oil reserves have increased constantly throughout the industrial age. If hydrocarbons become scarce enough, we will mine dumps and distill CO2. Some believe that many reserves replenish themselves over time, with oil from surrounding rocks slowly leaking in to refill deplenished reserves, but I don't have a source on hand for that. μηδείς (talk) 15:05, 7 April 2017 (UTC)
  • The definition of Oil reserves is tricky. Specifically, a "proven oil reserve" (which is what is usually meant by the term) is a reserve that is technically profitably exploitable at the current market price of oil. That is, some company has drilled and demonstrated that the oil is actually there, and that it is not too expensive to extract that oil at today's price. Recently, some large oil companies were required by US SEC rules to remove billions of dollars of "proven oil reserves" from their balance sheets. Those reserves were booked when oil was at $100/bbl in 2014, but they are not economically recoverable when oil is at $50/bbl. This goes back to the OP's question: "running out" of oil is a complicated concept. -Arch dude (talk) 17:13, 7 April 2017 (UTC)

• • • Thanks, an interesting comment, and one that shows the effect of supply and demand. The pdf downloadable at the link on the left of http://www.capitalism.net/ covers this at length. Basically, no commodities market has been cornered, unless you think of the extinction of certain organisms. μηδείς (talk) 19:49, 7 April 2017 (UTC)

April 7

"Death by old age"

1. Did humans of earlier times die because they appeared very old? 2. Did they attribute "old age" as the cause of death? 3. Why do humans want to live a long life, and at the same time, reproduce a lot of offspring that survive? 4. How can both desires (the desire to have viable and fertile offspring and the desire to live long) be sustainable? 5. Why can't humans let themselves die so that will make room for their descendants or relatives' descendants? 50.4.236.254 (talk) 03:00, 7 April 2017 (UTC)

This is not a forum for debating opinions
The following discussion has been closed. Please do not modify it.
It always seemed sloppy to me to attribute any death to old age alone. There is always a specific cause of death, they are just too lazy to bother to determine what it is. StuRat (talk) 03:24, 7 April 2017 (UTC) The OP is taking a rather fascistic view of the world. Be that as it may, if the deceased is old, and there is no indication of foul play, then it is unlikely an autopsy will be done. Hence it remains "old age". ←Baseball Bugs What's up, Doc? carrots→ 03:47, 7 April 2017 (UTC) "Unknown" would be more honest, as they have no idea if the person was poisoned, etc. StuRat (talk) 04:02, 7 April 2017 (UTC) If foul play is suspected, they would do an autopsy. ←Baseball Bugs What's up, Doc? carrots→ 04:07, 7 April 2017 (UTC) Sure, but it's unlikely to be suspected if somebody is elderly, isn't it ? StuRat (talk) 04:26, 7 April 2017 (UTC) It depends. When someone is elderly and very rich and the only other person present at the time of death becomes very rich because of it, the police definitely take a closer look. --Guy Macon (talk) 04:43, 7 April 2017 (UTC)

Humans want to live long and to reproduce as much as possible because these are inherent properties of all life (as we know it, Jim), although probably only humans are sufficiently self aware to want them consciously – have you ever met anyone who genuinely wants to have a shorter life merely for the benefit of others?

In a finite world, these two drives are indeed not sustainable if unchecked, but until very recently in our evolutionary history, there were very few of us (or our ancestors) on a large planet, so there was room for expansion – migration served to lessen problems of overpopulation until recent times, only now are we bumping up against the limits.

In most societies for most of history and prehistory, older people (where they survived, as some always did and all hoped to) were only supported by their own families, and with high rates of child and general mortality they had to consciously choose to have as many children as possible to ensure this happened. However, in modern times societies are becoming sufficiently rich, well-organised and humane to begin to support old people on a society-wide basis by such mechanisms as occupational and state pensions.

Societies have also greatly reduced mortality through sanitation, health services etc, so initially a continuingly high birth rate can lead to a local excess of population. However, it is observable fact that as people in such societies become richer, the average number of children born to each couple drops towards or below the number necessary to merely sustain the population (which is about 2.1, given that some people do not pair up and/or reproduce at all): this leads to a demographic problem of increasing numbers of old retired persons (who do not create more wealth) being supported by a decreasing number of younger, working and wealth-producing persons.

Currently the populations and wealth of several rich Western countries are sustained (or are increasing) only because of migration from other parts of the world. If we could manage to distribute wealth throughout the world so as to make everyone sufficiently rich, the problem of overpopulation would likely disappear and be replaced by one of a potential shortage of people in general, and younger (economically productive) people in particular. {The poster formerly known as 87.81.230.195} 90.217.249.244 (talk) 13:29, 7 April 2017 (UTC)

I numbered the OP's questions.

1. No, one's appearance alone cannot cause one to die.

2. Unanswerable because anything might be attributed as a cause of death. However "old age" has always been conceived as approximately the last say 33 to 25 % of the prevailing Longevity which was shorter in the past. Thus in using modern standards we can say that in preindustrial times, due to untreatable disease, accidents and malnutrition, many people died without reaching old age.

3a. Not all humans want to live a long life. The issue arises most in life-and-death situations where The will to live often separates those that live and those that do not.

3b. Not all humans want a lot of offspring. Children can be the desired or accidental result of informal or formal heterosexual partnership and are conventionally expected to support continued survival of the Nuclear family. Male heirs, especially the firstborn, are favoured in many inheritance systems for their earning and fighting potential, even to the extent of abandoning female babes.

4. It requires Luck one supposes and industriousness to sustain long life with many offspring.

5. Natural attrition handles this issue which sounds like a question of impatience. Blooteuth (talk) 14:09, 7 April 2017 (UTC)

• People who live outdoor lives tend do darken and wrinkle by their 40's, looking 60, while people who use parasols stay pale and supple. The term "redneck" began as an insult, since day laborers had red necks.

See also tha aging here from 1984 to 2002. μηδείς (talk) 19:43, 7 April 2017 (UTC)

• "Old age" is not a single cause of death; there are many aging-associated diseases - see death by natural causes. Though yes, people both ancient and modern often assume dying when one is old is inevitable or inherent, and incorrectly attribute death to it directly. Certainly lucky individuals in ancient civilizations died in their 70s and 80s as modern people do, but not very many of them. I expect hardly any or none of our ancestors pre-agriculture lived that long, but no records were kept in pre-historic times, by definition, so it's difficult to know for sure. Human instincts about reproduction and self-preservation are due to the environment we evolved in, but we layer on top of that our emotional and intellectual desires, which depend on personality and culture, so not all people make the same choices with regard to their own interests vs. the interests of their children. Some animals have lots of offspring and some have very few; some die when reproducing, and some try to live a long time and reproduce multiple times. The strategy of few offspring at multiple times has worked well for humans because of our big brains that need to be trained but are very good at obtaining food, shelter, and security from predators and competitors. Menopause is very rare among animals because living beyond fertile years is not of evolutionary benefit. Over most of the time we have evolved as a species, humans didn't live beyond their fertile years. Only in recent times have there been enough humans to worry about exhausting the planet's resources, so our instinctual desires don't take that into account. However, I will point out that before modern health care, economic prosperity, and birth control, very large families were typical. Now in developed countries, most people choose to have far fewer children, mostly because they are no longer needed as agricultural labor, and the chances of a small number surviving long enough to have grandchildren is very high. People's desire to have sex seems to be pretty much the same, so one way to make the desire to have children sustainable is to use birth control and only have children at about the rate of replacement. If everyone did that, the human population would stop growing and it's likely we could maintain that level despite increasing worldwide prosperity (and thus use of resources) through technological advancement or reallocation of resources. -- Beland (talk) 10:01, 9 April 2017 (UTC)

Schwarzschild geodesics - references

The Schwarzschild Geodesics page gives formulae for the effective potential and the perihelion shift which apply when the orbiting body is not an infinitesimal mass. The formulae look right. However, I have been through virtually all of the references on the page and all give the corresponding formulae for the case of an infinitesimal mass, only. For my own investigations, I need a reference for/ more information about the formulae as they are presented on this page. I - and presumably other readers - would be grateful if the authors could provide such a reference. Could they? — Preceding unsigned comment added by AussieFinn (talk • contribs) 06:53, 7 April 2017 (UTC)

I wikilinked the page reference. Blooteuth (talk) 13:13, 7 April 2017 (UTC)

What other cities and highway lighting authorities are eliminating/eliminated HPS streetlights?

New York City's switching to kindof white LEDs. Too purple. Sagittarian Milky Way (talk) 16:00, 7 April 2017 (UTC)

Fremont, California is just completing a shift from HPS to LED. Much bluer, but much closer to actual "white" than the hideous orange HPS color. -Arch dude (talk) 16:41, 7 April 2017 (UTC)

HPS isn't hideous, mercury vapor lights that make people look like cadavers are hideous. Sagittarian Milky Way (talk) 16:55, 7 April 2017 (UTC)

I agree with Arch dude, high-pressure sodium is hideous, though I'd describe it as "pink" rather than "orange". Seeing the clouds all lit up pink is really disturbing. Low-pressure sodium (yellow) is better; aesthetically there's not that much to choose, but at least the astronomers can filter it out, given its narrow wavelength band. --Trovatore (talk) 19:10, 7 April 2017 (UTC)

I'd think green mercury vapor clouds would be even more hideous and unnatural looking. Maybe it's just what I'm used to. Also pinkish-orange light causes low dark adaption loss for its brightness and disappears at a relatively high brightness since rod cells are about as sensitive to it as to the borderline ultraviolet. Red light affects rod cells even less but who would want blood-red clouds and red streets with horrible ability to distinguish colors? At a location dark enough to be a Californian amateur astronomer's dark sky site the clouds are probably too dark to show color anyway. Sagittarian Milky Way (talk) 16:34, 8 April 2017 (UTC)

Here in Fremont, they used "yellower" 3000K LEDs on the residential streets and "bluer" 4000K LEDs on the main arteries. They say that the 3000K has less glare but the 4000K provide better visual discrimination, whatever that's supposed to mean. -Arch dude (talk) 01:56, 8 April 2017 (UTC)

Don't think it is practical to ask for a list. All around the world, HPS is gradually being replaced by LED because they are more economical. Just as HPS replaced electric incandescent street lights, and incandescent replaced gaslight that came before it.--Aspro (talk) 18:31, 7 April 2017 (UTC)

So it's more like candles, horses and steam trains going away than something still speculative? Dirigibles were supposed to replace ships weren't they? Sagittarian Milky Way (talk) 23:27, 7 April 2017 (UTC)

Aside: Might be worth asking you local lighting authority what LED's they use if your that curious (as a tax-payer you are entitled to this as a right). US authorities are well know for going for the very cheapest. If their using cheap LED's with a big spectral gap between red and blue wavelengths then you will 'perceive' purple. This isn't a spectral colour like violet. Instead it it a mixture of red and blue. I'm in the UK and so our LED street lights are now on. Can not perceive any purple in them what so ever ! So it can't be down to the technology but down to what brand of lumière your local authority is using.--Aspro (talk) 19:22, 7 April 2017 (UTC)

• The big issue is that blue light messes a lot more with nightime circadian rhythms than do red/orange. μηδείς (talk) 19:24, 7 April 2017 (UTC)

Debate irrelevant to the question
The following discussion has been closed. Please do not modify it.
Then close the curtains when you to go to bed! Do you want other drivers to be alert when your on the road? Speaking this, as someone that has has what is known as SAD. It is the intensity that throws me off kilter. Once indoors there is little blue. That is not exactly right because I have a colour-match florescent (6400 K) tube in my kitchen to give good colour rendition when preparing food. But come night time, all the foods has been prepared and I just use the worktop lighting – which has a warm colour. Found this out' when I found, if I drove home from work in the summer with sunglasses on and closed the blinds on arriving home, I had no problem going to sleep. Whilst getting home late at night after being in a television studio, I was wreaked the next day because it took so long to get off to sleep the night before, due to the intensity of studio lighting. Proved this to my satisfaction because I also do photography with photofloods. The eye does have these blue sensors that promote the hormone responsible. Yet if this hormone level is keep low, then as soon as one gets indoors one starts feel dog-tired and after some 20 mins one want to go to sleep. Would you believe it. More than one doctors early solution was to prescribe me sleeping tablets ( because I have a server form of SAD) when a pair of Ray-bran’s worked out better. Close the curtains and wait 20 minute, during which time you can get all your clothes ready for the next day. --Aspro (talk) 20:56, 7 April 2017 (UTC)

Rome [1]. Why the love affair with sodium lighting? The residents of Hackney, blessed with its beautiful clear white lights, would complain when they had to go into neighbouring Islington with its dingy cost - cutting sodium lamps. Anyway, white light is good for you [2]. 86.147.208.18 (talk) 14:01, 8 April 2017 (UTC)

Engineers and project managers

Do engineers and project managers generally tend to stay in one industry for their career or do they change? Clover345 (talk) 16:56, 7 April 2017 (UTC)

I don't know how easy it will be to find a reference for that. Switching industries requires a change in specialization. In my experience, engineers become more specialized the longer they work in a specific field. Project managers do not. So, I would expect engineers to be less likely to move away from their field of specialization and to a field that is new. 209.149.113.5 (talk) 18:23, 7 April 2017 (UTC)

• Well, my dad's a project manager, and he has done everything from built hotels at the Jersey shore, a mental hospital in Harlem, shut down a state's (I won't name which state) nuclear program, while also building other nuclear plants, built oil pipelines and a luxury hotel in Seoul. Hope that helps.

Oh, and, basically, the essence of his job is supply chain management although he's also done on-site inspections, and testified in many lawsuits as a witness or expert witness. μηδείς (talk) 19:35, 7 April 2017 (UTC)

When a battery has 10000 mAh

Does the 10000 mAh relate to a standard benchmark voltage? Or, to a concrete voltage a battery is made for? But some batteries can output different voltages, what does it mean to have 10000 mAh then? And why the m, and not just say 10 Ah? — Preceding unsigned comment added by Hofhof (talk • contribs) 23:56, 7 April 2017 (UTC)

It relates to the nominal voltage of the battery. For NiMh it's 1.2 V per cell and LiPo may be 3.7 V but will otherwise be specified by the manufacturer. ----Seans Potato Business 04:19, 8 April 2017 (UTC)

• First of all, remember that a "cell" is one unit and a "battery" is one or more connected together - usually in series. The nominal cell voltage is fixed by its chemistry, but multiple cells connected in series will multiply this voltage.

Capacity relates to a couple of voltages: the initial voltage for a well-charged cell and then the minimum voltage that the cell should be discharged to. As the cell is discharged, the terminal voltage falls (actually the internal EMF stays constant but the internal resistance increases, so a lesser proportion of the voltage is apparent on the external terminals). Some cell types are known for gradually dropping their voltage, others stay mostly constant but then fall sharply once "flat". Old zinc-carbon flashlights were dim, but usable, for much of their life - rechargeable NiCd packs for cycling had a reputation for needing a spare, as they would give bright light, then suddenly cut out altogether. For Li-po this discharge voltage limit is an important limit - the cell may be permanently damaged if over-discharged. Some Li-pos (better cells, large batteries) have an inbuilt protection circuit to prevent this.

The current at which the cell is used also depends on the cell size - large cells may supply a greater current, small cells either cannot supply this much, or may perform poorly if a large current is drawn and may only offer a reduced capacity. It may also be harsh on the cell and reduce its overall working life. Assuming the same technology, the capacity of a cell is related to its mass of reagents (comparable to the volume), the current to the area of its electrodes. So a "wide, shallow" cell may give a greater current than a "narrow" cell, even when it has less total volume - for an extreme example of this, see the Polapulse battery [3], which was developed to be extremely thin, yet give a high current in short bursts.

This capacity is the "useful" energy within the cell. Not all of it, but the part that can be accessed and turned to use.

Another aspect to note is that "claimed" capacities printed on the cells is often simply a lie. Li-pos at present are over-rated by factors of 3× to 10×! Those .99c cells on eBay from China are not a good bargain, and usually have less capacity than a modern AA NiMH. A chemical argument shows the minimum mass and volume for any possible Li-po cell and that shows around 3600mAh as the maximum for a 18650 format cell. Good cells, mostly from Japan, might have 2/3rd of this capacity. The Chinese ones regularly claim 3× as much as possible, and about 10× their actual. Andy Dingley (talk) 11:12, 8 April 2017 (UTC)

In terms of measurement units there is no difference between 10000 mAH and 10 Ah. However the actual measurement of battery capacity must be done at an appropriate discharge rate for the battery, typically chosen for 20 hours discharge time. For lead acid batteries Peukert's law predicts that a higher discharge rate will yield a lower capacity. Quoting capacities of small batteries in mAH avoids suggesting that the battery is intended for amp-sized continuous current, while car starter batteries that are rated for much larger currents have their capacities quoted in Ah. Blooteuth (talk) 22:56, 8 April 2017 (UTC)

April 8

Am I right-handed or left-handed?

I don't know whether I am left-handed or right-handed. When I was a child, I began writing with my left hand and then, when I was a teenager, I trained my right hand to write. Also as a child, I played piano for 2 years; and now, I play piano intermittently for about a year. The piano trained me to use both hands. I can use a right-handed can opener and right-handed scissors easily. When I cut food, I find that cutting with my right hand is much more easier than with my left hand. When I ride my bicycle, I can lift my right hand while my left hand holds the handle, but when I switch hands, I find it very hard to lift my left hand. Am I right-handed or left-handed? Or is handedness a spectrum? 50.4.236.254 (talk) 01:21, 8 April 2017 (UTC)

According to the handedness: "There are four types of handedness: left-handedness, right-handedness, mixed-handedness, and ambidexterity." I'd bet you're the 3rd one. --Hofhof (talk) 01:26, 8 April 2017 (UTC)

Brooks Robinson batted and threw right-handed, but signed autographs left-handed. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:42, 8 April 2017 (UTC)

Did you know Hideki Matsui batted left for the Yankees cause he beat the local kids so bad they made him bat from the wrong side? Sagittarian Milky Way (talk) 17:11, 8 April 2017 (UTC)

Interesting story. A lot of great hitters taught themselves to bat lefthanded on the theory that it puts them a step or two closer to first base, along with the natural tendency of a righthanded pitcher to bring the ball more to their favor. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:20, 9 April 2017 (UTC)

I'm righty batting left; to me it feels natural to pull with the stronger arm. (The fact that my left eye is better for distance could also have something to do with it.) --Trovatore (talk) 01:48, 10 April 2017 (UTC)

That can figure into it too. It's kind of analogous to a backhand shot in tennis. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:28, 10 April 2017 (UTC)

It is a spectrum - most people can use both hands for at least some things, and it is perfectly possible to learn to use the less dominant hand (if you lose one, you have no alternative but to learn). However, if your first instinct as a child was to use the left hand, then that is probably the dominant one. Wymspen (talk) 09:36, 8 April 2017 (UTC)

 

Did anyone else flash on Guys and Dolls at the title of this question? --Trovatore (talk) 09:47, 8 April 2017 (UTC)

For those of us unfamiliar with that story, could you elaborate? ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:17, 9 April 2017 (UTC)

It's a line from the movie (not sure about the play). Thug asks another thug, "Am I right or left handed?", thug 2 responds "How would I know?", Thug1 says "I'll give you a clue." and pounds him in the face with one hand or the other. - Nunh-huh 05:06, 9 April 2017 (UTC)

Sky Masterson decks Big Jule. But I don't think a gentleman would refer to Sky Masterson as a "thug". Big Jule, yes. --jpgordon^{𝄢𝄆 𝄐𝄇} 14:38, 9 April 2017 (UTC)

Thug is as thug does. But I'm no gentleman :) - Nunh-huh 14:48, 9 April 2017 (UTC)

Sky was not a thug, he insists, stamping his little feet. --jpgordon^{𝄢𝄆 𝄐𝄇} 23:51, 9 April 2017 (UTC)

Yeah, Jerry Orbach didn't think so either. He too was wrong. :) - Nunh-huh 04:52, 10 April 2017 (UTC)

In that scene, Masterson used violence in the proper defense of another. It was the only instance (that I recall at least) of him using violence in the entire film, and I do not think any off-screen incident was even alluded to. He was a gambler, not a thug. --Trovatore (talk) 04:57, 10 April 2017 (UTC)

Nutrient-dense food with high risk of bacterial and parasite infection vs. nutrient-scarce food with high risk of chronic illnesses

I always wonder what kind of metric people use to assess whether something is "healthy". It seems that, whatever you eat, there are people who say there are bad things in everything. So, it's damn if you do and damn if you don't. Hamburgers, French fries, and soda pop are portrayed as "unhealthy". But no one seems to be concerned with eating an apple or red lettuce leaf straight from the store or pick-your-own-vegetable farm. I wonder what would happen if a person just doesn't care about health and buys fruits and vegetables from the grocery store and eats them completely uncooked and unwashed for the sake of time-saving convenience. Never mind the taste of it. I know many vegetables taste bitter, but if a person is hungry, he doesn't care and would eat the bitter vegetables raw. Or he can eat the sweet fruits. And nuts and seeds and avocados. And tofu is eaten straight from the container, because tofu is cooked by the manufacturer. I am not sure which is worse - eating nutrient-dense food straight from the grocery store or pick-your-own-produce farm (after purchase, of course) with possible risk of catching an acute illness and pesticide poisoning or eating nutrient-scarce, energy-dense food with excessive sodium and excessive amount of highly absorbable sugars with possible risk of developing a chronic illness. Plus, people in a poor country may drink water and catch a parasitic infection or boil water to kill parasites, and even though people in a rich country can drink chlorinated tap water for free, they choose not to and drink some kind of sweet beverage instead, and each beverage is labelled with health claims, like "vitamin C" or "caffeine" or "B vitamins". Do people really know what is "healthy"? Or is everyone making stuff up and basing their opinions on correlations? 50.4.236.254 (talk) 03:43, 8 April 2017 (UTC)

You can look at what indigenous people eat and how well they do on various aspects of health compared to us, see e.g. here. Typical results are that they are more prone to infections, but they get a lot less heart disease and strokes. So, it seems to me that all we need to do is eat more vegetables, eat less meat and use less cooking oil (replace refined oils by walnuts and chia seeds). Count Iblis (talk) 08:22, 8 April 2017 (UTC)

You have to accept a risk. No food is without some risk, but no food at all is invariably fatal. Wymspen (talk) 11:17, 8 April 2017 (UTC)

Dying is the ultimate time-saver, at least for the deceased. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:16, 9 April 2017 (UTC)

There are certainly scientific assessments of what people need to eat to stay healthy long-term - see healthy diet. Yes, the risk of foodborne illness is determined by the type of food (for example milk can incubate dangerous microorganisms much more easily than a banana, which is why it is pasteurized) but also by the conditions and practices at the source (is animal excrement allowed to touch the lettuce? are toxic pesticides used or is it organic?) and food preparation, handling, and refrigeration. There are some limitations to nutrition science (it is difficult to do ethical experiments on people that might injure them, and humans and our diets are very complicated and generally not limited to the lab environment) and to anyone's ability to assess the safety practices of any particular food supplier. If you want to know if it's better to eat a hamburger or an unwashed apple, there are dozens of factors to multiply in each case, and it's very specific to the supplier, so there's no general answer I can give you, but it's a question that's possible to answer with more than just made-up opinions. I think people who follow scientifically grounded advice on diet and food safety really can "eat healthy" in both senses. It is very true that a lot of everyday people don't follow this advice, in many cases due to ignorance and in many cases in the short term it makes them unhappy not to eat what they desire. A lot of food marketing these days does make incorrect or misleading health claims grounded in sales not science; it's possible stronger government regulation could fix that. -- Beland (talk) 09:38, 9 April 2017 (UTC)

"are toxic pesticides used or is it organic?" is a false dichotomy Nil Einne (talk) 10:43, 9 April 2017 (UTC)

It was a good point as if it was organic, it is likely to have made contact with animal excrement. Graeme Bartlett (talk) 14:00, 9 April 2017 (UTC)

Depends on what one means by organic. To a chemist it means something entirely different than it does to a marketing professional. --Jayron32 15:27, 10 April 2017 (UTC)

Why was azeotropic isopropanol not sold in stores in the past?

Only 70%? (your location may be different) Now they even sell 50% for the cheapskate, lol. Sagittarian Milky Way (talk) 16:10, 8 April 2017 (UTC)

Sold for what purposes ? As a disinfectant ? StuRat (talk) 16:17, 8 April 2017 (UTC)

Yes. Sagittarian Milky Way (talk) 16:35, 8 April 2017 (UTC)

It likely has to do with antimicrobial/disinfectant activity, which does change depending on the concentration. 70% has been shown to be quite effective. See CDC. --OuroborosCobra (talk) 16:57, 8 April 2017 (UTC)

April 9

Plutonium and its electrical conductivity

Why does the electrical conductivity of plutonium, in the temperature range of 100 to 400 K, rise with increasing temperature?

This phenomenon is called a "negative temperature coefficient (of resistance)", but no article on Wikipedia I can find explains why this happens, though that link includes some examples. It appears there is more than one reason this can happen. This source lists some possibilities in its introduction. Someguy1221 (talk) 01:00, 9 April 2017 (UTC)

It may be like a semi-conductor - the concentration of charge carries increase with temperature in this range. Ruslik_Zero 08:32, 9 April 2017 (UTC)

The effects of caffeine and alcohol

Caffeine is a stimulant. Alcohol is a depressant. If a cup of green tea and a cup of alcohol (wine, champagne, beer) are drunk at the same time, then what kind of effect do both have on the body? If a person is mentally depressed, then can he drink some caffeine? Can alcohol be drunk to calm a person with mania? 50.4.236.254 (talk) 02:09, 9 April 2017 (UTC)

Alcohol can be a stimulant or a depressant, depending on the dosage. Note that these terms don't refer to mental depression or mania, but rather physical stimulation and depression, such as heart rate, blood pressure, etc. There's some overlap between them, but they are not identical. StuRat (talk) 02:17, 9 April 2017 (UTC)

Alcoholic drinks have more rapid short-term effects, especially when the drink is carbonated, because alcohol readily passes through cell membranes into the bloodstream and brain. Its immediate effects are decreased anxiety and motor skill, hence the prohibitions on driving. The effects may proceed to euphoria and intoxication. Blooteuth (talk) 11:59, 9 April 2017 (UTC)

• As I have seen it put, if you combine alcohol and caffeine, what you get is a wide awake drunk. At a biological level, the mechanisms of action of alcohol and caffeine are quite different. Some of their high-level effects cancel to some degree, but many do not. Basically the same things apply to the other combinations mentioned in the question. Looie496 (talk) 14:35, 9 April 2017 (UTC)

Are nuts made of cells?

Looking to improve Nut (fruit) with the answer to this question: Are the nuts that we eat made of plant cells, with cell walls and everything, or are they just piles of nutrients hoarded for nearby cells to use? This has inexplicably started to concern me every time I chomp down on one. 8) -- Beland (talk) 10:03, 9 April 2017 (UTC)

The nut is a seed so it must contain living cells if it is to germinate. I would assume that most of the nutrients are stored inside cells rather than between them, but perhaps an expert can confirm this? Dbfirs 10:55, 9 April 2017 (UTC)

Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent (not opening at maturity) seed, such as an acorn or hazelnut. Blooteuth (talk) 11:34, 9 April 2017 (UTC)

Every part of a plant starts as a living cell. Some cells (see Sclerenchyma develop very think and solid cell walls, and the inside of the cell dies - these form the fibres in wood and the shells of nuts. Depending on the age of the nut, some of the living cells from the kernel may also have died, and the fats they stored may have leaked out. The nut you eat probably has a mixture of living cells, dead cells, and some nutrients which have leaked out of cells. Wymspen (talk) 11:38, 9 April 2017 (UTC)

Will the human population reduce in numbers because of global climate change?

We don't answer requests for opinions, predictions, or debate. 50.4.236.254 (talk) 22:18, 9 April 2017 (UTC)
The following discussion has been closed. Please do not modify it.
If the polar ice melts completely and floods and buries the coastal cities, along with the disastrous natural occurrences (earthquakes, tornados, hurricanes, fires, volcanos), then will the human population decline in number? 50.4.236.254 (talk) 12:36, 9 April 2017 (UTC) Probably not, because these changes will occur over decades or even centuries, giving most people enough time to move inland. The ultimate Q is how this will affect the planet's ability to grow food. While some land will be lost to flooding/contamination with salt water, other land, like that currently covered in permafrost, will open up to farming. In many cases this land currently lacks much soil, but that will develop in time, from plants and then trees that will grow there. Of course, over such long time frames other technologies, like hydroponics, may become more widespread. StuRat (talk) 18:33, 9 April 2017 (UTC) Due to the speculative nature of the question, the answer is definitely "Maybe." ←Baseball Bugs What's up, Doc? carrots→ 18:43, 9 April 2017 (UTC) According to this site, the world population growth is currently over 22 million per year, so you would have to drown that many every year to stop population growth, by that method. This is not going to happen, so we need to look at effects on the food supply, instead. StuRat (talk) 19:05, 9 April 2017 (UTC) It will decline in number long before that. Our civilization depends on agriculture, international trade is very important. The 2008 financial crisis demonstrates that there are weaknesses in the way we manage the system. Even if there are no fundamental problems with the production of goods, the system can crash. That's like an air-crash in clear weather due to only pilot error. I don't want to be in such a plane, certainly not if the plane were to enter an area of heavy turbulence. It then doesn't matter that the plane is designed to handle the turbulence well, that's not relevant if the pilot is too incompetent. So, a relatively minor event is all that's needed to destroy our civilization. Consider e.g. a prolonged drought that would force China and India to import the food that they normally grow themselves. They have more than enough financial reserves to buy the food for the, say, 2.5 billion people for many years in a row, but this would mean that the US and the EU would have to export all that food leading to shortages. That's not going to happen, they'll impose an export ban. This will then cause the global trade system to collapse. If you can't buy what you need on the market if you have enough money, then that's the end of the market. So, the global economic system will collapse, the only way that this could be prevented is if there were a World government, a single authority that could manage the situation. Count Iblis (talk) 19:35, 9 April 2017 (UTC) I agree that the rate of increase in population is unlikely to continue at the present rate, and that a major disaster will probably have an effect on the birthrate as well as on the population, but I think you are being over-pessimistic about the likelihood of a collapse in global trade and the necessity for a world government. Dbfirs 20:06, 9 April 2017 (UTC) The need for a world government may be more to avoid a nuclear war (or biological war, antimatter war, or whatever other nasties we come up with). StuRat (talk) 20:47, 9 April 2017 (UTC) @StuRat @Baseball Bugs @Count Iblis @Dbfirs Is it hard to understand "We don't answer requests for opinions, predictions or debate."? Blooteuth (talk) 21:04, 9 April 2017 (UTC) Maybe you missed where I said "Maybe." ←Baseball Bugs What's up, Doc? carrots→ 21:17, 9 April 2017 (UTC)

April 10

Transgender suicide rates

I'm looking for sources on transgender suicide rates. Benjamin (talk) 03:42, 10 April 2017 (UTC)

[4] — Preceding unsigned comment added by Hofhof (talk • contribs) 11:17, 10 April 2017 (UTC)

UV-vis spectroscopy

I've asked this once before, but nobody answered: In UV-vis spectroscopy, which wavelengths are the best for determination of aqueous Cu²⁺, Al³⁺/AlOH²⁺/Al(OH)₂⁺, and PO₄^3-/HPO₄^2-/H₂PO₄^-? 2601:646:8E01:7E0B:B50C:9D96:7F66:5859 (talk) 05:45, 10 April 2017 (UTC)

I think the UV-vis graph will show you which wavelengths are the best for determination of those aqueous chemicals. The graph will have wavelength at the X-axis and absorbance at the Y-axis. The peak of the curve means that the absorbance reaches a maximum at the corresponding wavelength. In my experience, UV-vis is done through software that is connected to the spectrophotometer machine, and the software will just output the information you want. You just have to set the range of wavelengths. 50.4.236.254 (talk) 12:51, 10 April 2017 (UTC)

Downsides of fresh beef and natural preservatives/colors/flavors

I know many restaurants are trying to bring in customers by promoting "fresh beef" and "no artificial preservatives/colors/flavors". Though, this means that the food will have an increase in sodium intake, because sodium chloride, for centuries, has always been used as a natural preservative. Does this mean that the fresh beef will have higher content of sodium in order to preserve the beef? What kind of natural preservatives/colors/flavors are harmful in restaurant portion sizes? 50.4.236.254 (talk) 12:43, 10 April 2017 (UTC)

I'm a veggie, so this just ain't my party, but I don't recall restaurants pushing "fresh beef" as a good thing. If anything, high-end beef is sold on how old it is, and the premium product makes a point of it being "aged for 28 days" etc. Some meats (and fish!) are sold by freshness being a great virtue, but not beef.

No comment on salt levels. Andy Dingley (talk) 12:49, 10 April 2017 (UTC)

Interesting. Wendy's keeps promoting "fresh beef" in commercials, and McDonalds is trying to switch to fresh beef to stay competitive. I think that's a trend, because the fast food companies think that using fresh beef will attract more customers. By the way, is "veggie" some kind of vegetarian or a vegan? 50.4.236.254 (talk) 12:57, 10 April 2017 (UTC)

"is "veggie" some kind of vegetarian or a vegan?" Yes. It's a fairly common umbrella term. I happen to be vegetarian, so I eat eggs, dairy, but not fish.

I'm also British, if that makes a difference for which adverts I see. I don't think we have Wendys here, but McD's are busy advertising about the source of their beef, how local and how happy the cows are. In the UK animal welfare is a bigger current issue than simple quality. Although there was a recent McD campaign to try and counter the 'McD's is "all lips and arseholes"' viewpoint that does tend to circulate. Andy Dingley (talk) 13:15, 10 April 2017 (UTC)

I think many Westerners and Indians are lacto-ovo vegetarians. East Asian vegetarians are closer to ovo-vegetarianism (though eggs may be considered a luxury product, so veganism is the default), because of the lack of dairy farming and consumption. Soy milk production is very similar to cow's milk production, and tofu is like cheese. Cheese usually contains a lot of sodium content, while tofu can be flavored with salt or spices. A quick scan of a vegetarian menu in America hints that American vegetarians really like cheese. 50.4.236.254 (talk) 14:20, 10 April 2017 (UTC)

"Fresh" in the McD context, at the moment, is talking about fresh v. frozen. --jpgordon^{𝄢𝄆 𝄐𝄇} 13:17, 10 April 2017 (UTC)

Think some are falling to see the Sales & Marketing angle being used here. Like any good magician they use 'distraction' and misdirection to fool their audiences. 'Fresh' is the current word now. There is growing concern, that a few countries (like for instance the US) are using antibiotics as a growth promoter for their livestock (especially beef) with a total disregarded for the problems that such usage may bring to the final consumer. We are already running out of effective antibiotics and intensive farming methods are making this crisis far worse, by becoming the breeding ground for more antibiotic resistant bacteria. So to stem this negative publicity, the S&M's are promoting the word 'fresh' , 'no artificial preservatives/colors/flavors', as if it also means natural, wholesome and safe. --Aspro (talk) 15:50, 10 April 2017 (UTC)

Is 580°F twice as hot as 60°F? and other weird temperature math

I recognize that saying "120°F is twice as hot as 60°F" doesn't make sense, because the Celsius doubling equivalent of 60°F, ~15°C would get you 30°C, or 86°F.

I understand both Fahrenheit and Celsius have "arbitrary" zero points, and Kelvin uses an *absolute zero*, but converting to Kelvin, then back, doesn't seem right either as it yields bizarre sounding results, like that in the title.

Are there any other units of measurement that have this issue?

Is there a better way to consider the concept of "twice as hot"?

Thanks!

- MacAddct1984 ^{(talk | contribs)} 13:25, 10 April 2017 (UTC)

• For the kinetic theory of gases, which is as good a meaning of temperature as anything, then yes, 580 °F (578 K) is indeed twice as hot as 60 °F (289 K).

I work with lasers, and have worked with plasmas. Where they have "negative" temperatures, on account of being so hot. They produce a condition (for the energy distributions of the atoms within them) of "population inversion". As the word "inversion" might suggest, this is in some, rather arcane, ways comparable to a temperature that would be negative. Andy Dingley (talk) 13:39, 10 April 2017 (UTC)

Heat content also needs to take into account the amount of material (usually mass or mole amounts) and its specific heat capacity rather than just raw temperature; for example a liter of water at some arbitrary temperature (say 25 degrees C) has a LOT more thermal energy than does a liter of air at the same temperature; and a liter of water has more thermal energy than does a milliliter of water. Concepts like enthalpy or internal energy are better for quantifying relationships. Temperature really isn't a "countable" thing in the way that energy would be. Saying something is twice the temperature is almost like saying red is twice the color as blue is... --Jayron32 13:44, 10 April 2017 (UTC)

You're right that converting to Kelvin is the only way that "twice as hot" is literally true, so if you mean anything else you should avoid using the phrase in any context where accuracy is important.

I don't have a cite, but I've noticed that rarely in some contexts "twice as hot" might use room temperature as a baseline. (If you have two overheating electronic components, the one that's 130F might be "twice as hot" as the one that's 100F because what you care about is the heat added by that component, but you don't see that usage often.)

In general, though, I've only commonly heard this expression used in casual conversation as a hyperbole where no actual measurements are implied. ("Texas weather is twice as hot as Maine weather!")

The other part of your question is easier to answer. There aren't too many units of measurements that have non-zero baselines like the common temperature units, but units that are nonlinear have a similar problem. A sound that is "twice as loud" as a 1 decibel sound will not be 2 decibels. An earthquake that is "twice as strong" as a 1 on the richter scale will not be a 2 on the richter scale. Etc.

13:51, 10 April 2017 (UTC)

The decibel (dB) is not a unit of sound level, despite frequent misuse. It is 0.1 times the logarithm of a ratio. A sound Loudness must be expressed in units such as dB SPL (or for perception of single tones dBA) that define what is the 0 dB reference. "Twice as loud" is then by physical definition +3 dB (but the human ear limits the range that can be heard or tolerated.) Blooteuth (talk) 15:05, 10 April 2017 (UTC)

Sure, Decibel SPL. Fair enough. Point is, it's logarithmic, so it doesn't double or halve as one might otherwise expect. ApLundell (talk) 15:21, 10 April 2017 (UTC)

Which, of course, hints at other Decibel-based units that answer the question. The other one you might commonly see is dBm (decibel milliwatt) used to compare radio signal reception. (You're most likely to see this measuring wifi reception.) This is particularly resistant against easy doubling or halving because your wifi reception is almost certainly negative dBm even though obviously a positive amount of power is being detected.ApLundell (talk) 15:31, 10 April 2017 (UTC)

Musical pitch is also a nonlinear scale. Each one-octave increment is "twice as high" in frequency (two octaves up is four times as high, three octaves is eight times as high). DMacks (talk) 15:40, 10 April 2017 (UTC)

• (ec)Well, it may seem bizarre, but it's the only (?) definition that makes physical sense. In thermodynamics, temperature is (e.g.) a measure for the average kinetic energy of particles of an ideal gas. If you double the temperature measured in Kelvin, you double the kinetic energy of the particles. --Stephan Schulz (talk) 13:51, 10 April 2017 (UTC)

• Any time people don't have a universal concept of the baseline, this situation can occur. If one plane is in level flight at a height of 1000 feet and another is directly above it at 2000 ft, one might say the second is "twice as high". But if they then continue flying straight forward over a 500-foot mountain, it's pretty confusing to say that the second is now "three times as high" as the first, but compared to the ground they are now only 500 ft and 1500 ft respectively. So instead one references sea level rather than ground level for altitude, but that means 2000 ft vs 1000 ft compared to the ground might be much greater than "twice as high" by visual appearance if the ground is high. DMacks (talk) 14:04, 10 April 2017 (UTC)