Wikipedia:Reference desk/Archives/Science/2016 May 2

= May 2 =

Dremels
Could they, have they, been used for home dentistry? This is not a medical Q, it is a dentistry Q.--178.103.251.111 (talk) 22:39, 1 May 2016 (UTC)


 * You could try googling your many questions first. I sense a pattern to them that is making me suspicious. --Aspro (talk) 23:12, 1 May 2016 (UTC)
 * The reference desk policy is about not giving any medical advice or diagnosis, that does not "exclude" questions about dentistry. The benefit of answering your question has to outweigh the possibility that this is something you are considering doing yourself, and obviously you just writing that you aren't, isn't good enough evidence to convince us that there is any good real reason that anyone here should seriously answer your question. The primary purpose of the science reference desk is to help find and point people to relevant references related to scientific subjects, your question does not qualify, even loosely. Vespine (talk) 00:01, 2 May 2016 (UTC)
 * Maybe he's looking to do a remake of Marathon Man. ←Baseball Bugs What's up, Doc? carrots→ 00:06, 2 May 2016 (UTC)


 * Medical questions are OK, as long as you're not looking for advice, and this promises the most entertaining search results. YouTube boasts multiple videos like .  I haven't searched the Darwin Awards yet... a fun question to drill down into. Wnt (talk) 00:21, 2 May 2016 (UTC)
 * Just a bit. ←Baseball Bugs What's up, Doc? carrots→ 00:30, 2 May 2016 (UTC)


 * Hey Bugs, you made me titter with that witticism (not a lot -- just a bit).--178.103.251.111 (talk) 23:08, 2 May 2016 (UTC)
 * It wasn't a real joke. It was just a drill. ←Baseball Bugs What's up, Doc? carrots→ 02:18, 3 May 2016 (UTC)


 * Wikipedia has an article about Dremel which is a brand of rotary tools suitable for use in the workshop. Another article describes the modern professional Dental drill which is characterized by high precision and needs to be disinfected between usages. Dentistry is the branch of medicine where licensed professionals treat the teeth. The Ref. desk will not speculate about unprofessional "home" tooth treatment or with misuse of equipment that may have occurred. AllBestFaith (talk) 09:30, 2 May 2016 (UTC)


 * When I was doing brain surgery on rats, we used dremel tools to drill holes in the skull. They could be used for dentistry in a pinch, but are much more unwieldy than a proper dental drill. Looie496 (talk) 00:13, 3 May 2016 (UTC)

hmmmm
Why does Vanilla has some unnecessary Hydrogen bonds in a circle? Why can't H0 and OCH3 connect to the rest without this circle? --Ip80.123 (talk) 08:32, 2 May 2016 (UTC)


 * Those are carbon bonds. They are completely necessary to keep the molecule existing. Sagittarian Milky Way (talk) 08:51, 2 May 2016 (UTC)
 * See Aromaticity. The equivalent aliphatic aldehyde without the ring is 4-hydroxy-4-methoxybutanal, which (as far as I can tell) doesn't have any commercial uses. Tevildo (talk) 09:01, 2 May 2016 (UTC)
 * That chemical has a bunch of literature hits. "Commercial" is an unusually strict limit on why someone might care about a chemical:) The original poster really needs to clarify what is being envisioned as the structure "without this circle". I can think of lots of possible meanings, which have various levels of interest vs nonsense ideas to discuss. DMacks (talk) 14:11, 3 May 2016 (UTC)
 * See hydrogen bond for what a hydrogen bond is. For the "unnecessary bonds in a circle", see double bond to get started, then aromatic ring and resonance (chemistry) for advanced concepts. Wnt (talk) 10:26, 2 May 2016 (UTC)
 * If it was, it would be a cyclopropene, rather than a benzene (cyclohex-1,3,5-ene) based compound. LongHairedFop (talk) 17:55, 2 May 2016 (UTC)


 * Also, that hexagon in the middle is the Kekulé format for drawing a benzene ring. Not sure if the OP recognized that.  The OP may also want to brush up on Skeletal formulas.  -- Jayron 32 18:03, 2 May 2016 (UTC)

Exothermic reaction
why do I get an exothermic reaction if I fill sugar into a "Zero Drink" bottle? For example Sugar into the Coa-Cola-Zero. in just a few seconds shoots out the Cola out of the bottle when I fill sugar into it. Does so reacts the carcinogenic aspartame with sugar? Or why is the drink so unstable --Ip80.123 (talk) 08:40, 2 May 2016 (UTC)
 * This is discussed in some detail at Diet Coke and Mentos eruption. -- Jayron 32 11:14, 2 May 2016 (UTC)
 * Aspartame isn't carcinogenic. shoy (reactions) 13:21, 2 May 2016 (UTC)
 * How do you know this reaction is exothermic? If I mix baking soda and nitric acid, I get bubbles, but not an exothermic reaction. --OuroborosCobra (talk) 14:23, 2 May 2016 (UTC)
 * Actually, I'm 99% certain the reaction is endothermic. Since there is not a proper chemical reaction here, just a phase transition: carbon dioxide going from the aqueous phase to the gas phase.  That phase transition should always be endothermic.  -- Jayron 32 14:27, 2 May 2016 (UTC)
 * whispers* was trying to get the questioner there; I suppose its the chemistry TA in me. --OuroborosCobra (talk) 14:29, 2 May 2016 (UTC)
 * whispers back* I can't let a chemistry question go unanswered. I suppose its the chemistry teacher in me.  -- Jayron 32 14:30, 2 May 2016 (UTC)
 * As a non-chemist with a loud voice ;-) can we not just put a thermometer in it? DrChrissy (talk) 14:36, 2 May 2016 (UTC)
 * You could just hold it. You'll feel it get colder.  -- Jayron 32 14:50, 2 May 2016 (UTC)

No dear Jayron 32, Mentos very often has 0% sugar in it. And mentos does a reaction also with regular normal cola, when I fill sugar into normal cola there happens nothing. Yes it is carcinogenic, shoy. It is. --Ip80.123 (talk) 09:21, 3 May 2016 (UTC)
 * If you can't be bothered to read the articles we have linked for you, then we cannot help you. -- Jayron 32 11:41, 3 May 2016 (UTC)
 * Ip, the reason why Mentos does this even containing no sugar is that this isn't a chemical reaction, it is a physical reaction. That you have observed this is a great hint, but rather than applying the scientific method, you seem to have rejected your results based on preconceived notions. As a physical reaction, it doesn't matter what chemical species is present as long as other physical properties are met, such as a rough, high surface area material. I've done the same thing using salt. You need nucleation sites, not a specific chemical species. No bonds are being made or broken. --OuroborosCobra (talk) 12:01, 3 May 2016 (UTC)
 * Safety of aspartame would disagree with you, unless you're trolling with your definition of the word. shoy (reactions) 14:11, 3 May 2016 (UTC)

Energy of elementary particles and forces
Why do elementary particles in theír ground state never lose their properties and keep moving forever? What is their continuous energy supply? '202.58.203.82 (talk)' —Preceding undated comment added 09:23, 2 May 2016 (UTC)


 * They don't need a continuous supply of energy, they just need not to lose energy during their interactions with other particles in order to keep moving forever.   D b f i r s   09:33, 2 May 2016 (UTC)
 * Newton's First Law of Motion says a particle either remains at rest or continues to move at a constant velocity, unless acted upon by a force. Thus no external supply of energy is needed for the particle to continue moving indefinitely. AllBestFaith (talk) 09:35, 2 May 2016 (UTC)
 * Elementary particles obey more complex laws, such as Quantum mechanics, while in general the principle of Newton's first law holds, there are some complexities, such as the problems of charged particles accelerating (see Larmor formula) that have to be accounted for by quantization of energy as explained by QM. -- Jayron 32 12:47, 2 May 2016 (UTC)
 * Yes, I originally started typing a link to Newton's First Law above, then deleted it because of the complexities. The energy argument holds, doesn't it?    D b f i r s   13:03, 2 May 2016 (UTC)
 * They do, and Newton's first law holds, broadly speaking, however thinking about elementary particles as little rigid spheres flying through space creates MAJOR issues that can only be resolved by quantum mechanics. I just don't want people getting the idea that an electron is a tiny little sphere orbiting a bunch of tiny little spheres we call protons and neutrons.  That sort of model doesn't hold up.  -- Jayron <b style="color:#090">32</b> 13:40, 2 May 2016 (UTC)
 * I hold up that model of "solid spheres orbiting solid spheres" all the time. As an example of a model that is nonsense. DMacks (talk) 14:03, 3 May 2016 (UTC)
 * I was not asking about solid spheres, but about energy. What is the true nature of energy, and why is it constant?202.58.203.82 (talk) 03:52, 4 May 2016 (UTC)
 * The general answer you'll see in a university level textbook is that it's because the universe is time invariant. In other words, for most purposes, the laws of physics today are the same as they were yesterday and as they will be tomorrow.* Noether's theorem states that this kind of invariance means something is being conserved, and in this case, that conservation law is conservation of energy. So from that perspective the reason that energy is conserved is that the laws of physics are constant with time (you might ask why they are constant, but intuitively it makes sense). Smurrayinchester 09:57, 4 May 2016 (UTC)
 * * I'm sure there was a discussion here about one specific case where the laws of physics are not invariant - the expansion of the universe - and how this means that in some specific circumstances energy is not conserved: a photon from the early universe will get redshifted by the expansion of space, which causes its energy to decrease, but the energy doesn't go anywhere. I can't find it in the archives though. Smurrayinchester 09:57, 4 May 2016 (UTC)
 * What if the enery of the photon goes into expanding the universe? In tandem with neutrinos maybe?202.58.203.82 (talk) 06:34, 5 May 2016 (UTC)

Civil engineers in the private sector
Do all civil engineers in the private sector have to think about profit for their company? 2A02:C7D:B957:F500:6596:55DA:4867:C538 (talk) 09:52, 2 May 2016 (UTC)
 * A business Company has a legitimate aim of gaining a profit unless it is constituted as a Nonprofit organization. Civil engineers who are employees are hired to contribute labor and specialised expertese to the company and they are assessed according to whether they achieve a profitable, productive and ethical performance. AllBestFaith (talk) 11:12, 2 May 2016 (UTC)


 * Not necessarily. Generally an employee has to think about whatever their immediate supervisor tells them to think about. A low level engineer in a large firm may spend little or no time thinking about profit, instead focusing on other details within various constraints provided for them.  A supervising engineer in a management role will likely have to devote a lot of thought to costs and economics.  A lot depends on the engineer's role and responsibilities within the company.  Dragons flight (talk) 11:23, 2 May 2016 (UTC)
 * Yes. Economics is a regular part of engineers education and generally one of the main concerns in design, tho companies like to keep that a secret. --Kharon (talk) 08:46, 3 May 2016 (UTC)

How to determine the average length of a generation in humans?
Is it okay to put a range from 15-45 years, with the mean, median, and mode? How do extreme ages factor in? 140.254.70.33 (talk) 12:14, 2 May 2016 (UTC)
 * It depends on who and when and where. But extreme age doesn't really figure into it - it's spawning the next generation. So if you produced kids when your were 25 to 35 years old, that's your own next generation. ←Baseball Bugs What's up, Doc? carrots→ 12:38, 2 May 2016 (UTC)
 * This looks relevant. -- Jayron <b style="color:#090">32</b> 12:44, 2 May 2016 (UTC)


 * Historically, it's 20 years (.i.e. "baby boom" 1945-1964, inclusive). Pop culture has tried to shorten it science has lengthened it.  It's not clear that the relationship is simply when parents have children but also sociologically relational (i.e. how much does a 35 y/o have in common with a 15 y/o?).  --DHeyward (talk) 15:39, 2 May 2016 (UTC)


 * There is plenty of data on the average age of women at the birth of their first child - which varies enormously in different parts of the world (from 18 in parts of Africa to over 30 in parts of Europe, and Japan). Try this list - https://www.cia.gov/library/publications/the-world-factbook/fields/2256.html 81.132.106.10 (talk) 21:30, 2 May 2016 (UTC)

What is the incentive behind taking vitamins as opposed to eating fruits and vegetables?
Some people don't want to eat fruits and vegetables? Vegetables taste bitter to some people? Fruits are too watery and messy for some people? Allergic reactions to some fruits and vegetables? 140.254.70.33 (talk) 12:45, 2 May 2016 (UTC)


 * Wikipedia has an article titled Food choice that would provide a place for you to start your research. -- Jayron <b style="color:#090">32</b> 12:49, 2 May 2016 (UTC)


 * There is such a range of fruit and vegetables that there really can be no justification for not eating any of them. There are vegetables which do not taste bitter, and fruit which is not watery or messy. Even allergies rarely mean that you react to all of them. 81.132.106.10 (talk) 14:11, 2 May 2016 (UTC)


 * It's easier just to pop a pill. ←Baseball Bugs What's up, Doc? carrots→ 14:59, 2 May 2016 (UTC)


 * Where would you pop it? I have a suggestion for you...--178.103.251.111 (talk) 23:15, 2 May 2016 (UTC)
 * I'll get back to you after your next block expires. ←Baseball Bugs What's up, Doc? carrots→ 02:15, 3 May 2016 (UTC)
 * Depends whether you get blocked before I do, doesnt it?--178.103.251.111 (talk) 22:51, 3 May 2016 (UTC)
 * Some reasons why people take vitamins (and minerals and other micronutrients):


 * 1) The mistaken belief that more is better. This isn't true of most micronutrients, and some, like vitamin A are even harmful if you overdose.


 * 2) To compensate for an unhealthy diet. Of course, this is of limited value, since not all micronutrients are provided in a form that can be readily absorbed in pill form.  Also, the pills won't get rid of the harmful things you eat.


 * 3) Vitamin D is a special case, since it's produced naturally in our skin from UV light. Since we are now trying to avoid UV light because it causes skin cancer and wrinkles, many people are deficient in Vitamin D.


 * 4) Vegetarians are another special case, since they may lack certain nutrients, like iron and vitamin B-12.


 * 5) Various health problems and/or meds may be cause to take other micronutirents. StuRat (talk) 00:17, 3 May 2016 (UTC)


 * The main incentive is the the amount of bull**** advertisements that tell people they need extra vitamins to maintain their health or avoid this or that disease or condition coupled with the ignorance of the reader who doesn't understand the fallacy of the suggestion. We are talking market forces as a driver, the acquisition of your money by unscrupulous companies. Richard Avery (talk) 06:56, 3 May 2016 (UTC)


 * Yes, advertising seeks to introduce then reinforce all the misconceptions about the health benefits of taking pills. StuRat (talk) 16:01, 3 May 2016 (UTC)


 * (Sorry, just a comment:) It's not really an either-or thing, and it at least seems like a cheap and harmless thing to do.  If you feel out of sorts, or somebody sniffled next to you in the office, or you binge on the bad stuff rather than the good, you take a pill.  There are a lot of Plan Bs in life. Wnt (talk) 10:45, 3 May 2016 (UTC)


 * They can cause harm, especially nutritional supplements from China, etc., which may have harmful ingredients not meant for human consumption. StuRat (talk) 16:01, 3 May 2016 (UTC)


 * Quite a lot of vegetables taste disgusting, or require what is perceived as an excessive amount of time and effort to turn into something palatable. People then eat less of the things than they are told they should, feel guilty, and take vitamins as a "well it's better than nothing" way of dealing with it. DuncanHill (talk) 16:10, 3 May 2016 (UTC)


 * But "taste disgusting" is a relative thing. If your normal diet is entirely junk food, then anything else may taste bad.  But, if you eat veggies regularly, they won't taste bad.  And if you were starving, they would taste delicious. StuRat (talk) 19:31, 3 May 2016 (UTC)


 * It's perfectly possible not to eat much veg without eating "entirely" or even any junk food. Some vegetables - potatoes, swedes, onions, runner beans for example, are delicious, especially with a bit of butter. DuncanHill (talk) 20:30, 3 May 2016 (UTC)


 * You eat Swedes ? I try to avoid cannibalizing Swedes.  I find Italians much tastier, as they have been pre-marinated in wine and garlic. StuRat (talk) 20:33, 3 May 2016 (UTC)
 * Just their meatballs. ←Baseball Bugs What's up, Doc? carrots→ 20:42, 3 May 2016 (UTC)
 * No one has mentioned that vitamin pills are Dietary supplements and as such are NOT regulated by the FDA, in the States anyway. By definition they are not intended to treat or prevent any disease, but the supplement industry is constantly pushing the boundaries of what kinds of claims they can get away with. Notice how many supplements and 'alternative medicines' claim they "boost the immune system", this is because this is a clinically meaningless claim and they can get away with it. Vespine (talk) 22:50, 3 May 2016 (UTC)

Does quantum physics really matter?
When we analyze phenomenon like consciousness? That's what comes to mind to me, since people talking about conscious often relate it to quantic phenomena. Anyway, do we understand something better about consciousness since quantum physics was discovered? --Llaanngg (talk) 16:47, 2 May 2016 (UTC)
 * There is no known direct connection between quantum physics and consciousness. See Wikipedia's article titled Consciousness which discusses it in some details.  Quantum physics has nothing in particular to do with it, excepting where quantum physics has to do with everything (such as how atoms and molecules work, etc.)  -- Jayron <b style="color:#090">32</b> 16:50, 2 May 2016 (UTC)
 * For starters, we don't understand quantum physics. YohanN7 (talk) 16:53, 2 May 2016 (UTC)


 * Quantum_mind describes how some people think that consciousness might somehow depend on quantum weirdness or other strange bits of quantum mechanics. The jury is still out of course, and our article reports no conclusive findings, just interesting hypotheses.  The Hard problem of consciousness, unsurprisingly, remains hard. SemanticMantis (talk) 16:55, 2 May 2016 (UTC)
 * Of course the word quantum is used A LOT in the context of consciousness by people who have very little idea what they're talking about to sound pseudo profound. Vespine (talk) 00:08, 3 May 2016 (UTC)
 * "Quantum" is used a lot by people who want to sound sciency or profound but have no idea what they are talking about. We have an article on Quantum mysticism if you want to read more about it. (I found the article trough the redirect "quantum quackery" which I think is a more apt description.) Sjö (talk) 07:39, 3 May 2016 (UTC)


 * In the mean time found: What the Bleep Do We Know!? and a review of itLlaanngg (talk) 17:48, 3 May 2016 (UTC)


 * People insist in not wanting to believe that our minds (and especially our conscious minds) are ruled by simpler "classical" laws of physics - so they clutch at the phenomena that are least well understood (at least by them!) - and that's quantum theory.  Sadly, this fails utterly to reveal any actual insights to the problem that aren't equally well covered by the chaotic behavior (in the mathematical sense of "chaos theory") of a system as ungodly complex as the brain.
 * Quantum theory is very important - but not at the level of such macroscopic things as neurons, synapses and such. SteveBaker (talk) 17:52, 3 May 2016 (UTC)
 * Well, technically speaking, all objects obey the laws of quantum physics: it doesn't stop working at some magical bright line. It's just that the laws of quantum physics reduce to the laws of classical physics (that is, they produce the same answers, to any meaningful measure) for any object larger than a molecule.  That's why we don't use complex quantum physics equations to model the behavior of macroscopic phenomena: while the Quantum models produce the right answer, the simpler classical models produce the same right answer. -- Jayron <b style="color:#090">32</b> 19:13, 3 May 2016 (UTC)

were the birds mating?
was walking down a sidewalk on a city street...just off the sidewalk on cement ground near a building two birds lying sprawled out in close proximity (actually touching I think) seemingly dead..my initial thought was that they had flown into the side of the building and were dead as a result..I then noticed one flutter so looked closer...nudged one with my foot...then they both jumped up and flew away like bats out of hell, seemingly completely healthy...it was very odd..I've never seen birds on the ground like this unless they were dead...the birds were black and about the size of a cardinal..this was in Michigan, USA....were the birds just mating? couldn't find much about mating positions for songbirds etc or anything quite like what I saw...68.48.241.158 (talk) 21:03, 2 May 2016 (UTC)


 * Most birds mate very quickly, only a second or so. Another suggestion is that they were playing dead to lure you away from their nest.  I suspect they had a nest with eggs in it (or maybe chicks) nearby that you didn't spot.  Also, if you are in the Northern Hemisphere, where it is now spring, it's a little late to just be mating now.  It's time for hatching now.  StuRat (talk) 00:05, 3 May 2016 (UTC)


 * Any references on the mating habits of birds so the OP can learn more about the subject? Or just half remembered factoids and suggestions?  -- Jayron <b style="color:#090">32</b> 01:13, 3 May 2016 (UTC)


 * yeah, from what I read I don't think it was mating activity either...it was strange...they were like zonked out dead and like practically right on top of each other...never seen anything like it....it's possible they were flying after each other and both ran into the building and were lying there stunned for a bit...I've seen birds chase each other around etc...I didn't sneak up on them but noticed them lying there and walked over so not like I scared them into playing dead..I didn't even know birds did such a thing...anyway..might just be one of those odd occurrences..68.48.241.158 (talk) 00:42, 3 May 2016 (UTC)


 * Help us out OP, we need more info to make even an educated guess. How were they touching? At the feet/beak/wing/tail/other? Did you see them land, if so how/where? What time of day was it? Did they make any noise? Was this a dense urban area or a suburb, or other? Were they perhaps grackles or starlings? (Probably not a red-winged blackbird?)
 * I have some suspicions but I'll save them until I get more detail :) In the meantime, you can check out our article on male-male competition, this book chapter,, or this  scholarly review article on the topic.  SemanticMantis (talk) 02:59, 3 May 2016 (UTC)


 * yes, something along the lines of grackles or starlings...was about 5pm, southeastern Michigan...in the downtown area of a suburban town center...lots of farmland/woods within a mile or two...they looked identical so likely the same sex...I'm certain the position they were in had nothing to do with me or my presence...I was the only pedestrian in the immediate area..they were lying side by side and I'm quite sure even touching....totally still for the first couple of seconds I noticed them from a distance...one then fluttered a little so I walked over and then nudged one with my shoe...they continued to appear dead or injured but then suddenly both flew off at a high rate of speed in the same direction and basically side by side...it was a strange nature encounter..68.48.241.158 (talk) 03:58, 3 May 2016 (UTC)


 * Sure sounds like playing dead to me, although perhaps just lying still so you wouldn't spot them. This strategy might be more effective against predators with worse vision than us.  Cats, for example, are good at spotting motion but seem to have trouble seeing much detail on still objects.  Note that the "completely still then escaping at full speed" pattern is one you see a lot in prey animals.  Once they realize they've been spotted, then it's time to change strategies and run for it (or fly for it, in this case). StuRat (talk) 05:17, 3 May 2016 (UTC)


 * I can find no reference to urban birds using distraction strategies to protect their nests which are usually built in available vegetation or in/on buildings or other available structures. The feigning dead strategy is more usually used by birds who build nests or incubate their eggs on the ground. Could they have been sunning themselves and had their eyes closed in the rapture of it. Richard Avery (talk) 06:49, 3 May 2016 (UTC)


 * If they were nearly on top of one another, only one of them would have been effectively sunning itself. Rather awkward for the one underneath... Evan (talk&#124;contribs) 07:47, 3 May 2016 (UTC)


 * And they may not be "urban birds", meaning those that regularly live in cities, like pigeons. They are close to nature, and we often get wild animals encroaching slightly into developed areas (or vice versa). StuRat (talk) 15:53, 3 May 2016 (UTC)


 * Clues: springtime, 5pm, lying on concrete. My guess: they were lying there soaking up the warmth that had been retained by the concrete from the sun's rays earlier in the afternoon. Akld guy (talk) 08:57, 3 May 2016 (UTC)


 * Thanks for the extra info. Here is a pay-walled article on male-male competition in the boat-tailed grackle, let me know if you'd like a copy. I think WP:OR the birds you saw were fighting. I say this because I've seen great-tailed grackles exhibit very similar behavior. In my case, I was sitting at an outdoor table in a light urban/suburban core context, and saw the fight start. After much squawking and flapping, they ended up with their feet clasped together. After some leg wrestling, they stopped, laying in the street, seemingly dead. But after they were suitably rested/disturbed, they both got up and left. Usually, these sparring matches among juveniles are fairly abstracted, but sometimes they can go pretty far. Things like grackles, sparrows, starlings, and other human commensal species often reach much higher densities in cities than they could in the wild, and this may increase the incidence and intensity of fighting for mates. This is of course not a positive ID of the behavior, but it does sound very similar to a strange bird fight I saw :)SemanticMantis (talk) 13:44, 3 May 2016 (UTC)


 * I think you're exactly right the more I've thought about it...they may have been sort of touching at the feet, as if they had been clawing at each other...but does seem they were perhaps in a daze from fighting/exhausted...and when I finally nudged at them it was enough to give them another burst of adrenaline to finally fly away from me...it was interesting..68.48.241.158 (talk) 14:02, 3 May 2016 (UTC)