Science desk
< December 13	<< Nov \| December \| Jan >>	December 15 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

December 14 edit

are imine groups stabilised by base? edit

My class always seemed to discuss imine in terms of equilibrium (e.g. excess HOH ==> hydrolysis; distillation of HOH and excess amine allows formation of imines), but it seems to me that an imine group would survive in water without being deaminated under basic conditions, whereas hydrolysis would be catalysed by acid. (Ignoring the fact that acid prolly changes the equilibrium by deactivating the amine.)

In neutral solution, assuming equal abundance of HOH and amine, would a C=N bond tend to equilibrate to 50% C=O and 50% C=N? I know the bond energies are different but NH2- is a bad leaving group, NH3 is a decent leaving group (sorta?), whereas HOH is only formed as a leaving group under much rarer conditions and certainly much rarer in base! John Riemann Soong (talk) 00:56, 14 December 2009 (UTC)[reply]

If you know there is a stability difference, it would be silly to assume there is an equal distribution at equilibrium. Thermodynamic equilibrium is the same as the balance of the forward and reverse reaction rates. General equilibrium direction is stated in the very first paragraph of the imine article. DMacks (talk) 14:06, 14 December 2009 (UTC)[reply]

Well yes, but mass action principles often seem to overrule enthalpy considerations. I'm wondering just looking at leaving group principles. John Riemann Soong (talk) 00:49, 15 December 2009 (UTC)[reply]

time/temperature formula edit

Is there a formula to convert cooking time sufficient to kill pathogens such as cooking chicken for 20 minutes at 170 to the time required to kill all pathogens at a temperature of only 120? 71.100.0.206 (talk) 02:03, 14 December 2009 (UTC) [reply]

Is that degrees Fahrenheit or degrees Celsius? You can't kill all pathogens at all at normal atmospheric pressure (except by burning the food); you need a pressure cooker to do that. Certain temperatures from 140 °F (60 °C) to 180 °F (82 °C), depending on the variety of food, will prevent the growth of bacteria and/or destroy any toxins that might have already been produced by bacteria, over the period of time food is normally held between cooking and serving (no more than 4 hours). Below 140 °F (60 °C) bacteria can grow and the heat can do more harm than good. --Jc3s5h (talk) 02:20, 14 December 2009 (UTC)[reply]

Fahrenheit. I read somewhere that vegetarians cook at 118 deg F so maybe the reason is only flavor? 71.100.0.206 (talk) 02:48, 14 December 2009 (UTC) [reply]

I would not recommend cooking chicken at either 170°F or 120°F. My meat thermometer says that, for poultry to be cooked it should reach a temperature of 190°F, and you're clearly not doing that if you're cooking at a temperature below that. Cooking chicken in an oven would typically be done at 200°C (~400°F) so trying to cook at the very low temperatures you're talking about seems an impossibility. --Phil Holmes (talk) 15:15, 14 December 2009 (UTC)[reply]

The 118°F thing may be a reference to a raw food diet, not an ordinary vegetarian diet, but the number is a little different than what our article says. For cooking meats at a low temperature for a long time, see sous-vide. And I don't want to eat chicken that's been cooked to 190°F. 165°F is plenty. -- Coneslayer (talk) 15:30, 14 December 2009 (UTC)[reply]

200 F sounds way too low, and it would take a very long time for the internal temp to creep up to 190. My old 1981 "Better Homes and Gardens Cookbook" says to roast chickens at 375, under 2 pound chickens at 400, turkey at 375, goose at 350, and foil wrapped turkey at 400. It calls for an internal temperature of 185 in the thigh meat as a doneness test. Edison (talk) 19:54, 14 December 2009 (UTC)[reply]

depurination edit

Why isn't depurination a much larger problem than it seems to be? I know there's BER, but I mean, a purine glycosidically linked to a sugar seems to be quite problematic, because purine seems to be a good leaving group, and that anomeric carbon is all the more reactive to SN2. John Riemann Soong (talk) 02:50, 14 December 2009 (UTC)[reply]

Also why isn't depyrimidination also a mutation regime? Glycosidic-bonded pyrimidines have a carbonyl at the 2' position, effectively making a 2N-nitrogen an amide (negative charge can be delocalised onto the oxygen) so a pyridine lone pair could be similarly delocalised. John Riemann Soong (talk) 03:09, 14 December 2009 (UTC)[reply]

Scanning for a lost cellphone edit

Hi, I've lost my cellphone. It might have been stolen (it's now blocked for outgoing calls, just in case) but it's on and I suspect it's in my house. I can call it and I get the "calling" sound in the phone I call from but I can't hear it ringing (if it's in the house, the sound must be off or it's surrounded by pillows or something). It's an iPhone but I think the WLAN is not transmitting when it's not being actively used. Is there any way I can "scan" my house for it using simple equipment, like a small radio? Would it be feasible to call the phone while walking around with a radio to see if I hear interference on the radio? If so, would anything other than a radio (just a small speaker, for example) be more likely to work? I'm of course also looking by conventional methods but I just moved and there's a lot of cardboard boxes it could potentially have fallen into (as well as the possibility that it is indeed not in the house). Thanks! Jørgen (talk) 11:23, 14 December 2009 (UTC)[reply]

It turned up without any scanning. But I still think it was an interesting idea... :-) Jørgen (talk) 19:38, 14 December 2009 (UTC)[reply]

Both wifi and bluetooth have RSSI that indicate roughly how close the transceiver is. If you have set your iPhone to automatically connect with a laptop or something you could maybe do some sort of triangulation, although it won't be very accurate. --antilived^{T | C | G} 23:22, 14 December 2009 (UTC)[reply]

The connection between blonde people and intelligence edit

I have a question, are blonde people really stupid? I mean, does being blonde affect your intelligence? —Preceding unsigned comment added by RocketMaster (talk • contribs) 13:35, 14 December 2009 (UTC)[reply]

Off course not. It is also not true that the chiken crossed the road to get to the other side. Dauto (talk) 14:40, 14 December 2009 (UTC)[reply]

But it is true that silly people post nonsense in Wikipedia at times. JamesBWatson (talk) 15:39, 14 December 2009 (UTC)[reply]

It's a perfectly reasonable question. Sometimes conventional wisdom is right, sometimes it is wrong. Determining which is the case for a particular piece of wisdom is a job for science, not for assuming it must be nonsense because you've been brought up with the dogma of equality. So, how about we try and actually find some references for the OP? --Tango (talk) 15:57, 14 December 2009 (UTC)[reply]

Indeed: intelligence is a combination of nature and nurture, and part of the nurture is attributable to one's appearance. A number of studies have shown that unattractive children receive poorer treatment from their parents, for example, which could lead to lower educational opportunities. --Sean 16:18, 14 December 2009 (UTC)[reply]

There could also be a case of self fulfilling prophecy. If culture views blonds as dumb, then smart women who do not wish to have such a stereotype may dye their hair a different color, resulting in a higher proportion of "dumb blonds". 65.121.141.34 (talk) 16:24, 14 December 2009 (UTC)[reply]

It is not a reasonable question. There is NO conventional wisdom about blonds being dumber. Just dumb jokes about it. Dauto (talk) 17:40, 14 December 2009 (UTC)[reply]

Perhaps "conventional wisdom" is the wrong term, but there certainly are people that believe blondes have a lower average intelligence. Jokes don't exist in a vacuum. Even if nobody believed it, it would still be a reasonable question. Empirically verifying things that everybody believes to be true is an important part of science. The refusal to even consider that your assumption could be wrong is the defining characteristic of a dogma, and dogma has no place in science. --Tango (talk) 17:54, 14 December 2009 (UTC)[reply]

Are you asserting, Dauto, that you are a master of every single one of the thousands of cultural enclaves that exist in all of the 192 countries in the world and that you are positive that nobody believes this? You're overstating. Please stop; this is the Reference Desk. Tango is correct. Let's find some citations. This link isn't one, but its hypotheses touch on why physical features and intelligence might theoretically be correlated (the claim is that genes set an upper limit for intelligence and that "genetic clustering occurs due to geographical isolation over long periods of time, and continues through inheritance", so you could see how, say, hair color and intelligence might be correlated because one particular group happens to be of a certain hair color and of a certain intelligence range. This is surely controversial but that's something to debunk with a link to a study, not by trying to shout it down). Comet Tuttle (talk) 18:00, 14 December 2009 (UTC)[reply]

We do have a dumb blonde which says "This stereotype (and the associated cognitive bias) may have some negative consequences and it can also damage a blonde person's career prospects. [1]" which I think calls into question the idea it's simply dumb jokes. Conciously the people may say it's a dumb jokes but the study here suggests subconciously at least they are being influenced. I have read of other studies before that have been summarised as "blondes really do have more fun" specifically they've found that people (or women?) who dye their hair blonde start to behave differently and also induce different responses from people IIRC. To put it a different way, as with many stereotypes, whether they have any truth or not, people subconciously at least respond to them. And in fact I agree with Tango here, as with many stereotypes there are certainly people who do conciously believe them to some extent.

And repeating what has been said above, it seems likely to me there will be some influence therefore on the blonde's 'intelligence'. To clarify, I should say I'm not referring to intelligence as defined by some IQ score but more generally in terms of knowledge and other things which make the difference between a 'smart' person and a 'dumb' person. Anyway if other people have lower expectations of that person and therefore the person is not pushed so hard to achieve and is given less opportunities to succeed (the study for example) it seems likely this will often negatively influence their intelligence. And conversely since when the person does have to do something they may have to put in less effort to succeed again that's likely to negatively influence their intelligence. Nil Einne (talk) 19:24, 14 December 2009 (UTC)[reply]

Tango, Equality is not a dogma. You seem to be confusing it with a virtually nonexistent belief that there are no differences between people. Equality is simply not taking one person's observed behavior or intelligence and attributing it to trivial factors such as appearance (i.e. blonde hair) with no non-biased attempt to find any actual evidence of a cause-effect relationship between said blonde hair and the specific behavior or intelligence, thereby wrongly assuming that all people with the same appearance (i.e. blonde hair) are less intelligent then non-blondes. --Itwilltakeoff (talk) 00:17, 15 December 2009 (UTC)[reply]

Equality is dogmatic for some people (like Dauto). Of course it isn't for everyone, for plenty of people it is just an assumption based on evidence, or lack thereof. The difference is whether or not you are willing to consider that it might be wrong. --Tango (talk) 00:53, 15 December 2009 (UTC)[reply]

Also, the Stereotype threat article may interest the OP.

Which leads to the vastly more interesting question of whether or not blondes have more fun. ~ Amory (u • t • c) 01:38, 15 December 2009 (UTC)[reply]

I mentioned the study earlier. I found some mention of it here [2] [3]. I couldn't find if it was published or where, one of the articles links to a press release which doesn't work, I didn't try that hard. Some obvious flaws occured to me when reading this study and when writing about it above which I didn't bother mention but found this which does a resonably job of highlighting them [4]. The second ref and [5] mentions some other studies with more ambigious results and [6] [7] suggests blondes may have more fun, unless they want to get married/settle down. It's apparently also a question which interested Darwin [8] [9] so I guess you're in good company for wanting to know. I also noticed this mostly unrelated thing about improvements in modelling blonde hair and the reasons it's difficult [10] which perhaps SB can help clarify if anyone is interested. Nil Einne (talk) 10:10, 15 December 2009 (UTC)[reply]

"It takes a smart woman to play a dumb blonde." (I don't remember who said that, but check out my search results in this Wikiquote search results).Civic Cat (talk) 20:10, 17 December 2009 (UTC)[reply]

What medicine stops the itchiness inside of nose? edit

This question appears to be a request for medical advice. It is against our guidelines to provide medical advice. You might like to clarify your question. Thank you.

Responses containing prescriptive information or medical advice should be removed and an explanatory note posted on the discussion page. If you feel a response has been removed in error, please discuss it before restoring it.

-- Scray (talk) 03:05, 15 December 2009 (UTC)[reply]

Irritation edit

Why does a body part become red when its irritated?Accdude92 (talk to me!) (sign) 14:43, 14 December 2009 (UTC)[reply]

I believe it is a histamine response. The redness is due to increased blood flow to the area. --Tango (talk) 15:06, 14 December 2009 (UTC)[reply]

Yes -- check out rubor. DRosenbach ^{(Talk | Contribs)} 03:10, 15 December 2009 (UTC)[reply]

Faroe Islands tunnels/civil engineering. edit

What are the main civil engineering companies, or company, in the faroe islands? I mean for instance who builds the most tunnels? —Preceding unsigned comment added by 188.74.72.115 (talk) 16:04, 14 December 2009 (UTC)[reply]

We have a List of tunnels of the Faroe Islands - there aren't that many of them. 75.41.110.200 (talk) 21:57, 14 December 2009 (UTC)[reply]

See the Miscellaneous section. By the way that's a real lot of tunnels for only 49,000 people to use. The Danish taxpayers have spent more than a billion Euros on them and now they want independance[11]. Alansplodge (talk) 23:25, 14 December 2009 (UTC)[reply]

Following a link in the Norðoyatunnilin article (the only one linked in the "list of" page), I find this page: http://www.tunnil.fo/Default.asp?sida=565 . From what I can read from it (Norwegian and Faroese separated some 700 to 1000 years ago, so not much) it seems NCC constructed that tunnel. In general I would expect most or all tunnels on the Faroes to have been constructed by foreign companies. Jørgen (talk) 07:33, 15 December 2009 (UTC)[reply]

Google also gave me this (only part of an article, but one more (or the same) example of NCC building a tunnel there) Jørgen (talk) 07:36, 15 December 2009 (UTC)[reply]

Tail on Human edit

Could this be true that some humans were born with a tail? This is video of a woman showing her tail note: it is a porn video. with a tail. —Preceding unsigned comment added by 74.14.119.246 (talk) 16:24, 14 December 2009 (UTC)[reply]

Well, who knows about the video—one should never look for reality in porn. But our article on Tail covers the possibility of human tails quite well, check it out. --Mr.98 (talk) 16:28, 14 December 2009 (UTC)[reply]

To put 98's comment in a different way, humans can have tails, but while I haven't looked at the video it's quite doubtful IMHO that the woman in the video really has a tail Nil Einne (talk) 19:21, 14 December 2009 (UTC)[reply]

I watched it and it was obviously fake. --Sean 22:12, 14 December 2009 (UTC)[reply]

Quite so. Martin Hogbin (talk) 11:13, 19 December 2009 (UTC)[reply]

Both my nephews were born with tails - instead of curving inwards, the coccyx curves outwards. --TammyMoet (talk) 18:42, 14 December 2009 (UTC)[reply]

See also our Atavism article. 87.81.230.195 (talk) 21:17, 14 December 2009 (UTC)[reply]

And Human tails and this [12] and [13] Alansplodge (talk) 23:19, 14 December 2009 (UTC)[reply]

Theories vs. laws (Re: Einstein) edit

Hi. I've been trying to figure why Einstein's theories of Relativity are still widely considered theories and not laws, and how there aren't even aspects of those theories that are considered laws per se. I know there have been discussions about the subject here already. What I want to know is if what I found at the Physical laws article is true (and would therefore explain calling Relativity a theory and not a law):

Physical laws are distinguished from scientific theories by their simplicity. Scientific theories are generally more complex than laws; they have many component parts, and are more likely to be changed as the body of available experimental data and analysis develops. This is because a physical law is a summary observation of strictly empirical matters, whereas a theory is a model that accounts for the observation, explains it, relates it to other observations, and makes testable predictions based upon it. Simply stated, while a law notes that something happens, a theory explains why and how something happens.

So, is this really true? Even if it is, I could argue that certain formulas or concepts within the theories of relativity could be isolated and named "laws", right? PS. I found it very curious to know that Relativity is the only item in the List of laws in science article that is still a theory... 190.157.136.97 (talk) 16:42, 14 December 2009 (UTC)[reply]

This issue has been discussed many times on the RD before. You may want to read those discussions first and then come back with anything that still confuses you Nil Einne (talk) 16:59, 14 December 2009 (UTC)[reply]

Yes, that definition is correct. "Still a theory" is nonsense - a theory is a good as it gets. "Theory" in science doesn't mean "something that hasn't been proven", as it does in everyday usage, since there is no concept of proof in science. Something like "E=mc²" could be described as a law, I suppose, as could "the speed of light is constant". They are simple statements that have been empirically demonstrated. The idea that theories become laws is just not how science works and is generally nonsense spread by creationists trying to discredit the theory of evolution. --Tango (talk) 17:02, 14 December 2009 (UTC)[reply]

For example, the Lorentz transform is a law which governs the composition of velocities in the theory of special relativity. However, this law only describes a small portion of the total class of phenomena which might be explained in a special relativitistic treatment. Compare, for example, how Ohm's law is the simplified governing equation for a more general theory of electrical conductivity and an even more general quantum theory of conductivity. Not only is the theory more complex, but it includes the law(s) as special-case simplifications of the general physics. Furthermore, different theories can support some of the same law(s), as is the case when a simpler theory is a proper subset of more generalized theory. Nimur (talk) 17:50, 14 December 2009 (UTC)[reply]

E=mc² is a law: it is a description of mass-energy equivalence. I suppose we could name it something like "the law of mass-energy equivalence". There are two different theories of relativity "special relativity" and "general relativity". --Jayron32 18:56, 14 December 2009 (UTC)[reply]

Don't forget Galilean relativity. Einstein wasn't the first to theorise about things being relative. --Tango (talk) 18:59, 14 December 2009 (UTC)[reply]

This is a very good article comparing evolution with gravity: Evolution as theory and fact. --Mark PEA (talk) 19:35, 14 December 2009 (UTC)[reply]

Actually, that article is not even a Good Article, much less a "very good article". Comet Tuttle (talk) 19:42, 14 December 2009 (UTC)[reply]

No, no, no! Nonsense. An article can be extremely good in every regard - but if nobody offers it to the WP:GA crew to check out, it'll never become a Wikipedia:Good article. SteveBaker (talk) 01:34, 15 December 2009 (UTC)[reply]

A law is just a theory with a good PR agency.Sjö (talk) 21:06, 15 December 2009 (UTC)[reply]

Yes, in physics at least there is no distinction between laws and verified theories. One problem is that the word 'theory' also includes more speculative theories such as string theory. Unfortunately there is no official system in science to declare theories laws when they are accepted. Martin Hogbin (talk) 11:19, 19 December 2009 (UTC)[reply]

foggy car windows edit

What atmospehric conditions must there be for a car's window to fog up?Accdude92 (talk to me!) (sign) 20:19, 14 December 2009 (UTC)[reply]

The basic cause is that the glass is colder than the air on one side of the glass. Based on the humidity of the air, there is a dew point (a certain temperature) below which the water evaporated in the air will condense into liquid. If the window is colder than the dew point of the air, water will condense on the glass in very small droplets, which is what makes it foggy. —Akrabbim^talk 20:27, 14 December 2009 (UTC)[reply]

Further to this subject, is there a good, cheap way to minimise the condensation that forms on the inside of a car's windows when it's parked outside during an overcast British winter? My car lacks air conditioning and the windscreen's air blowers (using engine heat to warm cold but humid exterior air) take a considerable time to clear it, as does the rear window's heating element. I have latterly resorted to driving with the side windows half-open for 10 minutes, which works but is no fun in the cold and impractical when it's raining. 87.81.230.195 (talk) 21:12, 14 December 2009 (UTC)[reply]

Clean windows fog up much less than dirty ones. I proved this to a coworker who refused to believe it because it meant that he had to do a minor amount of physical labor. I cleaned the passenger side of the windshield. Then, the next week, I saw him driving down the road leaning over so he could look out the passenger side of the car while the driver side was all fogged up. -- kainaw ™ 21:15, 14 December 2009 (UTC)[reply]

In order to fog up, the window needs Nucleation sites. Basically, in order to change phase from a gas to a liquid, the water molecules need some rough areas to "stick" to first. That's why dirty windows fog up so fast, the particles of dirt provide lots of good nucleation sites. If cleaning the window really well does not work, there are anti-fog coatings and sprays that you can buy at any auto supply store, or the automotive department at your local supermegamart. These are usually surfactants (i.e. soap) that prevents the water from forming tiny droplets. Window fog is essentially lots of little droplets, so by lowering the surface tension of the water, the water forms a thin sheet instead of droplets, and a sheet of water is much easier to see through than lots of droplets are. --Jayron32 21:29, 14 December 2009 (UTC)[reply]

As I remember from my (mispent) youth, a cut potato rubbed over the window helps - also it's not bad if your wiper dies and you want to drive in the rain (Mr. Plod might not approve). Way back in the 60-70's there was a product for the rear window called (I think) GnoMist - a thin sheet of plastic which clung to the screen (like some of those window stickers that aren't sticky), that helped to keep the back window clear, I assume the water did not like forming droplets on the surface. Make a mental note for your next car to get one with a heated front window - my Mondeo is just great in keeping the windows clear. Ronhjones ^(Talk) 21:49, 14 December 2009 (UTC)[reply]

I've never heard of GnoMist, but Rain-X and Aquapel are water repellent products available in the US which are supposed to reduce the amount of fogging on windshields. -- 128.104.112.87 (talk) 00:17, 15 December 2009 (UTC)[reply]

Thanks for the suggestions. I admit I'm not big on car cleaning, but I'll give the insides of the windows a go before my next trip. The outsides of the windscreen and back window are no problem. I think the main inside problem is that in our dank British winters, the car's interior never has a chance to dry out properly. Re getting a Mondeo next time, I prefer for various other reasons to stick with the Corsa (I'm on my third, having had Models A, B and C in succession), and in my now-unemployed state see little prospect of changing or replacing my current one for the forseeable future - I can barely afford to keep it on the road as it is! 87.81.230.195 (talk) 15:20, 15 December 2009 (UTC)[reply]

between large vision acuity edit

This is possible to say 20/100-1 or 20/200+1? What what does this mean? Is 20/100-1 mean like 20/120 and 20/200+1 mean like 20/170 or so? Doctors can do like 20/x+3 if vision is between 20/200 and 20/300, this do happen.--209.129.85.4 (talk) 22:02, 14 December 2009 (UTC)[reply]

I've never seen visual acuity quoted like that. Where did you see it? --Tango (talk) 22:25, 14 December 2009 (UTC)[reply]

Last doctor's visit one eye is 20/100-1 that's what the doctor wrote.--209.129.85.4 (talk) 22:29, 14 December 2009 (UTC)[reply]

Any changes the one is actually a lower-case L? Jc3s5h (talk) 22:36, 14 December 2009 (UTC)[reply]

For "Left eye"? Opticians usually use "S" (from the Latin for left) rather than "L", but I suppose it is possible. --Tango (talk) 00:49, 15 December 2009 (UTC)[reply]

It could be possible that the numbers are actually separate things. The first number (ex. 20/20 or 20/100) might represent the visual acuity expression, and the other number (ex. -1 or 0.5) might represent the number of diopters that the optometrist has prescribed for corrective lenses. 152.16.15.144 (talk) 00:48, 15 December 2009 (UTC)[reply]

Wikipedia:Reference desk/Archives/Science/2009 December 14

Contents