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August 24

What kind of lizard is this?

I found this little guy last Friday while looking at ghost towns in Juab County, Utah. Its environment is desert, if that helps any. I saw the same species of lizard on Antelope Island last May. The Raptor /_{My mistakes; I mean, er, contributions} 00:14, 24 August 2010 (UTC)

My guess is the Lesser Earless Lizard (Holbrookia maculata) who lost part of its tail. ---Sluzzelin talk 00:19, 24 August 2010 (UTC)

Completing my physics education

I'm enrolled in a physics undergrad program program in a Quebec university, which means that my program is three years instead of four years. The reason is that we have a CEGEP-system; that is, high school ends a year earlier and university starts a year later, with a two-year CEGEP thing in the middle. Now, normally this wouldn't be a problem, except that I took a total of three physics courses during my stint at CEGEP. And they were baby courses to begin with (classical mechanics without calculus, waves without the wave equation, etc.) I'm a little worried about the quality of my education, and that I will be behind those students who've had a four year education, so I've decided that I'll do some self-study to fill in the gaps. Here's my program schedule:

U1 Required Courses

(27 credits)

MATH 247 (3) Honours Applied Linear Algebra

MATH 248 (3) Honours Advanced Calculus

MATH 249 (3) Honours Complex Variables

MATH 325 (3) Honours Ordinary Differential Equations

PHYS 241 (3) Signal Processing

PHYS 251 (3) Honours Classical Mechanics 1

PHYS 257 (3) Experimental Methods 1

PHYS 258 (3) Experimental Methods 2

PHYS 260 (3) Modern Physics and Relativity

U2 Required Courses

(24 credits)

MATH 375 (3) Honours Partial Differential Equations

PHYS 253 (3) Thermal Physics

PHYS 350 (3) Honours Electricity and Magnetism

PHYS 357 (3) Honours Quantum Physics 1

PHYS 359 (3) Honours Laboratory in Modern Physics 1

PHYS 362 (3) Statistical Mechanics

PHYS 451 (3) Honours Classical Mechanics 2

PHYS 457 (3) Honours Quantum Physics 2

U3 Required Courses

(6 credits)

PHYS 551 (3) Quantum Theory

PHYS 352 (3) Honours Electromagnetic Waves

U3 Complementary Courses

(21 credits)

6 credits selected from:

PHYS 459D1 (3) Honours Research Thesis

and PHYS 459D2 (3) Honours Research Thesis

PHYS 469 (3) Honours Laboratory in Modern Physics 2

PHYS 479 (3) Honours Research Project

15 credits selected from:

PHYS 332 (3) Physics of Fluids

PHYS 434 (3) Optics

PHYS 479 (3) Honours Research Project

PHYS 514 (3) General Relativity

PHYS 521 (3) Astrophysics

PHYS 557 (3) Nuclear Physics

PHYS 558 (3) Solid State Physics

PHYS 559 (3) Advanced Statistical Mechanics

PHYS 562 (3) Electromagnetic Theory

PHYS 567 (3) Particle Physics

PHYS 580 (3) Introduction to String Theory

What texts would you recommend I look into? Thanks. (And if you're really generous, what complementary courses should I take in the third year?)76.68.247.183 (talk) 00:25, 24 August 2010 (UTC)

I'm somewhat unclear on what the question is. Are you currently starting the programs of courses outlined above and looking for advice on how to further supplement that on your own? Dragons flight (talk) 00:37, 24 August 2010 (UTC)

Yes exactly, sorry for being unclear. 76.68.247.183 (talk) 01:05, 24 August 2010 (UTC)

I would definitely call up the university and see if they can put you in touch with one of their advisors. What you are asking is very detailed and depends on a detailed knowledge of the unusual course you've done and the precise syllabus are pre-reqs of one you are going into - and the odds are slim that we'll be able to get you an answer that's any better than guessing. SteveBaker (talk) 00:43, 24 August 2010 (UTC)

That's too bad, but thanks anyhow. 76.68.247.183 (talk) 01:05, 24 August 2010 (UTC)

My advice, if you have time to spare for something like this, is to contact a lab that does something you are interested in and see if you can volunteer, or even get hired, as an undergraduate assistant. Practical research experience is worth ten times as much as studying. Looie496 (talk) 00:54, 24 August 2010 (UTC)

Thanks for the suggestion, I'll look into it. 76.68.247.183 (talk) 01:05, 24 August 2010 (UTC)

In reply to Dragons field, I parse the situation to be that the OP is about to start this year's Honours Physics program at McGill. I think in the OP's position, I'd be concentrating all of my efforts on getting through the first year, about half of which is mathematics. Lack of prior physics tuition looks only to be a problem from year 2 onwards. Only the OP will know his or her areas of mathematical weakness, but for instance, right now, a decent book on calculus might be indicated. --Tagishsimon (talk) 00:56, 24 August 2010 (UTC)

I think my math is fine (Cals 1 through 3, linear algebra, and even an intro to differential equations). My general misgiving not that I am improperly prepared, but rather that I'll miss out on some of the physics that, although interesting, isn't absolutely necessary for, say, grad school (which is what this program is preparing for). 76.68.247.183 (talk) 01:13, 24 August 2010 (UTC)

(ec) That's not really the way it works. In a three year course in any of the sciences, the first two years try to cover the material which ever practitioner in that science (here, every physicist) should know: in the final year, you get to drop some of the bits you don't like and specialize a little bit (but nowhere near as much as you specialize in grad school). By the time you get to the third year, there will be some of those optional courses that you just don't want to take because the subject matter doesn't interest you – it's pointless asking yourself which ones at the moment, because you haven't yet been exposed to the physics at university level so you don't really know what's going to interest you in two year's time or not.

In my own case (I'm a chemist, but the principles are similar), I was certain (and my grades backed me up) that I didn't want to be an organic chemist, so I specialised in my final year in inorganic and theoretical chemistry, not in organic or physical chemistry: I then did my PhD in inorganic chemistry. That doesn't stop me editing organic chemistry articles on Misplaced Pages, because I know the basics, I'm just not a specialist in that field: I have to look things up that a specialist would know almost instinctively, but at least I understand them when I look them up! Physchim62 (talk) 14:59, 24 August 2010 (UTC)

I don't see anything significant missing from the physics coverage compared to what is typical at other grad school preparatory programs. I will note that Solid State is often a required course, and some grad schools assume you've taken it, so that is probably a good choice under the optional work. I do notice that there doesn't seem to be any requirement for statistics or computer programming, both of which are skills that are very valuable to many practicing physicists. For some specialties (e.g. particle physics, string theory, general relativity) it would also be useful to take additional math courses (e.g. Group Theory, Differential Geometry, etc.). If you goal is to learn practical everyday physics, then I would suggest that Fluids is quite valuable (as well as being useful for some experimentalists). However, people focusing on nuclear and particle physics do often skip Fluids with no real detriment. Personally, I like Astrophysics for its breadth and ability to consider a wide variety of unusual problems. On the other hand, I've seen people who consider Particle Physics to be a critical bit that every physicist should know even though most will never use it for anything. Ultimately, I'd suggest you base those U3 choices on what interests you at the time. This is especially true if you are thinking about grad school at that point and want to try out a topic area you are thinking of specializing in.

I would also like to second the comment by Looie. If you think you might want to go to grad school some day, then getting involved with research (even as only a part-time volunteer) is probably the best thing you can do for yourself. Physics is a rich discipline, and undergrad programs often tend to try to cover all of physics, but in doing so it is easy to miss skills that are important in the day to day life of many researchers. For example, computer programming, statistics, electrical / circuit engineering, etc. Working in a lab can help you learn the mindset of a scientist and pick up some of those skills that may not be part of the curriculum. If you are interested in grad school, then getting involved in research as an undergrad is probably the single best thing you could do improve your chances with top schools. Of course, some areas of research will only be accessible to advanced students (string theory, particle physics, etc.), but many of the experimental projects have work that even early undergrads can be trained to do. Depending on your preferences (and other workload) it may make sense to wait till U2 before looking for a place to volunteer, so that you'll have a better foundation in physics, but I would encourage you to get involved in research no later than that if you do want go to a top school afterward. It is also not uncommon to see undergrads who volunteer a little bit during the school year but also work full-time (for pay) in a lab during the summers, so that is something to consider. A lot of potential opportunities aren't advertised, so it makes sense to learn the research interests of the various faculty and reach out to them directly. Dragons flight (talk) 14:48, 24 August 2010 (UTC)

You want http://www.oercommons.org/courses/collection/light-and-matter-physics-and-astronomy-resources -- start with the "Simple Nature" title to get an overview. For your third year, go with Fluids, Nuclear, Solid State, Advanced Statistical Mechanics, and Electromagnetic Theory to avoid the unapplied fluff. Ginger Conspiracy (talk) 22:56, 24 August 2010 (UTC)

Coral identification (from the Great Barrier Reef)

I'd appreciate any help you can give in the identification of these two corals. I've tried a fair bit myself, but didn't come up with much. Thanks. 99of9 (talk) 01:11, 24 August 2010 (UTC)

The spherical one is probably a porites, no idea which variety. Mikenorton (talk) 11:56, 24 August 2010 (UTC)

I'm not even convinced by that, it doesn't have "finger like" structure... --99of9 (talk) 21:42, 24 August 2010 (UTC)

There are many different types of Porites, not all of which have finger-like structure, see here for example, - that's particularly a reference to Porites porites I think. Mikenorton (talk) 22:05, 24 August 2010 (UTC)

Ok, so even the one sentence lead in the stub on porites is deficient! Our coverage of stony corals is surprisingly deficient compared to most other orders of animals I've seen. Thanks. I'd love to hear other opinions too. --99of9 (talk) 04:08, 25 August 2010 (UTC)

How would those dents in the top originate — damage, or does it naturally grow that way? Nyttend (talk) 11:59, 24 August 2010 (UTC)

They're certainly not recent damage, but perhaps some early damage has been grown over and left the dimples in the surface. --99of9 (talk) 21:42, 24 August 2010 (UTC)

What is Galactic Alignment?

Kindly enlighten me with a word i have come across Galactic Alignment.What would be its effect on earth. —Preceding unsigned comment added by 59.182.236.67 (talk) 07:25, 24 August 2010 (UTC)

Often, this sort of term ("galactic alignment", "celestial alignment", and so on), is used in a pseudoscientific way. In actual fact, astronomical alignments can and do occur, but they have little or no effect on Earth or any events here. A lot of mysticism and mythology has been concocted to conjure up "important effects", but in reality, any such alignment passes without really affecting anything. It's "neat" for people who like observing planets and stars. "Galactic" alignment is a pretty loose term - what, exactly, in the galaxy is aligning? Galaxies move very slowly; any "aligning" that they do with respect to anything else, especially as viewed from Earth, would occur over the course of millions of years. Nimur (talk) 07:53, 24 August 2010 (UTC)

The article covers this topic rather well. Bear in mind:

• the zodiac is a circle around the Earth, and the Milky Way is (in appearance) a circle around the Earth, so the two have to intersect, in fact twice. (Though since the center of the Galaxy is in Sagittarius, it is arguably the better of two choices)
• the Earth intersects as a function of precession, but when it intersects depends on what time of the year you look, since the Sun goes all the way around the Zodiac every year. So the choice of "winter solstice" for the alignment is one of four options for traditional solstices and equinoxes. (Even so, that's once every 26,000/4 = 8500 years
• the exact timing of the intersection depends on the exact middle plane of the Galaxy meeting the exact center of the Sun. But there's a huge amount of wiggle room there for the idea to be pounded around to meet the facts, because the Galaxy is a fuzzy object. I can't say exactly how much this blurs the time frame

In conclusion, it is not entirely a bogus concept - it does have a certain logic as a way to derive an astronomical Year Zero - but the 2012 thing is not an astronomical coincidence, so to speak. Wnt (talk) 15:01, 24 August 2010 (UTC)

Take a look at 2012 phenomenon for the interested. ~AH1 19:23, 26 August 2010 (UTC)

Histrionic Personality Disorder

Do people who have histrionic personality disorder cheat more often than other people? Have there been any studies done on this? I couldn't find any —Preceding unsigned comment added by 76.169.33.234 (talk) 07:59, 24 August 2010 (UTC)

See histrionic personality disorder. ~AH1 19:22, 26 August 2010 (UTC)

Already did, I asked only because there was no information about it. What would be the purpose of me seeing the article? It doesn't have the answer to my question. Not trying to be rude, but don't just answer to answer. Only answer with a useful answer. —Preceding unsigned comment added by 76.173.106.64 (talk) 03:23, 27 August 2010 (UTC)

Body Fat Level

Why is it that two people that are equally active and eat the same number of calories can weight different amounts? I know that their thyroid hormone levels can be different, but I can't see this making that much of a difference. Shouldn't they be both burning the same amount of calories? Can your genes make so much of a difference that one person will be overweight and the other very skinny? —Preceding unsigned comment added by 76.169.33.234 (talk) 08:02, 24 August 2010 (UTC)

See our article on Basal metabolic rate, which might vary widely between the two and is "usually by far the largest component of total caloric expenditure." Gabbe (talk) 11:23, 24 August 2010 (UTC)

Unfortunately, this article is not very complete - it gives simple formulae for BMR which do not admit easy change, and thus are not very satisfying for our purposes. See for a study in which BMR (also caloric intake) was rapidly altered in experimental subjects. Wnt (talk) 14:45, 24 August 2010 (UTC)

According to a study for the BBC's Horizon, Jan 2009, there seems to be pre-set fatness level for everyone, presumably genetically predetermined. They took otherwise healthy volunteers and fed them twice their normal calorie intake, whilst reducing the amount of exercise they took. The volunteers' weights did rise, but some of them only slightly. The BBC article is a bit light on the details, and doesn't have a decent cite, but it might be a useful area to start websearching from. CS Miller (talk) 15:08, 24 August 2010 (UTC)

This question gets asked at least 1000 times a day in doctors offices around the world. Yes, it is quite obvious that two persons of similar size may have dramatically different calorie needs and that one may lose and the other gain on the same calorie intake. This inherent rate of calorie expenditure for basically staying alive is referred to as the basal metabolic rate. There are genetic components, with genome wide array studies discovering increasing numbers of genes associate with differences; these are unchangeable. There are probably early life programming factors that are not easily changed at an older age. There are likely ongoing factors that can gradually change the BMR of adults, such as activity level, diet composition or pattern, stress, illness, etc. The BMR is at least partly controlled by a hypothalamic mechanism that functions as a "set point thermostat", shifting energy expenditure mechanisms when weight exceeds or falls below the set point. It is a safe bet that a hundred pharmaceutical companies have lab scientists hard at work at finding ways to safely manipulate your BMR and when someone has an effective, safe product, it will be marketed to you every 15 minutes on every website, spam email, or television channel and will be more famous than Viagra. I long ago lost count of the number of times I have answered this question for overweight people or their relatives. Pass it around. 159.14.241.253 (talk) 16:39, 24 August 2010 (UTC)

That argument applies only to products that are patented and sold under monopoly - there is no special funding for other aspects of diet and lifestyle that might affect weight, including herbal supplements such as guggul (as well as related Commiphora described by Dioscorides). Once a weight loss product is developed and marketed, as a rule, it causes sudden death in large numbers, e.g. 2,4-dinitrophenol, amphetamines, fen-phen, and ECA stack supplements. This is one issue on which people definitely need to do their own research, and not rely on the regulatory system to support or protect them. Wnt (talk) 17:34, 24 August 2010 (UTC)

The idea that people can "do their own research" about something like this is idiotic. There is less safety and efficacy information available about anything sold as a "dietary supplement" than about anything FDA-regulated. The whole point of the "dietary supplement" status in the US is to avoid the onerous rules that attempt to provide at least some degree of assurance of safety and efficacy. For things sold as dietary supplements, "do your own research" is a mendacious delusion. Thanks but no thanks. 159.14.241.230 (talk) 17:13, 25 August 2010 (UTC)

A lack of regulation doesn't mean a lack of information. And the rules aren't always really about safety. The meadow saffron described in the Ebers papyrus for use against pains in the lower extremities, and denounced as poisonous by critics from Dioscorides to the present day, is exactly the same drug as the Colcrys sold for fifty times the price of previous colchicine on account of FDA approval and FDA monopoly in the U.S. Because the dosage of colchicine has traditionally been pretty much "use as you feel like", the control over concentration (which predates the FDA-approved version) really isn't such a large advance. Likewise, consider aspirin, which causes gastrointestinal bleeding, not caused by the more advanced preparation of willow bark extract found on a clay tablet from the city of Ur, several centuries before the birth of Abraham. Wnt (talk) 14:35, 26 August 2010 (UTC)

Nonsense; fuzzy stories for the ignorant, but completely untrue. The whole reason for formation of the FDA was to provide standardization of preparations and laws against adulteration. When people know no one is checking and there are no penalties for fraud they will sell you anything, like the melamine in the chinese baby formulas. Those who know no history peddle bullshit and are ripe for the latest incarnation of the eternal political and medical cons. 76.117.81.78 (talk) 23:26, 28 August 2010 (UTC)

See Somatotype and constitutional psychology. Most people have a given body mass range set by their bone structure. ~AH1 19:21, 26 August 2010 (UTC)

This was a respectable theory back in the 1920s and it is maybe sorta kinda a little bit true that BMR and living conditions being equal, there is a relationship between skeletal build and body fat. The point the questioner was asking about however is that BMR still varies among people of roughly the same size, so this is not a very helpful answer. 76.117.81.78 (talk) 23:26, 28 August 2010 (UTC)

Need help understanding some poorly written chemistry info...

From the writings of a colleague: In high temperature, sodalite would transform to cancrinite of which twelve-ring channels cage prefer bigger cation. So when Ca2+ exists in solution, it prefer occupying the cage to instead of two Na+s, forming Na6•2CaCO3•nH2O.

My attempt at rephrasing: Sodalite transforms into cancrinite when exposed to high temperature. Cancrinite's twelve-ring channel cage prefers larger cations and thus preferentially selects Ca2+ over two Na+s when the former is present in solution. The final product in this case is Na6•2CaCO3•nH2O.

Does that make sense?

First, my chemistry knowledge is next to nothing - for example, I have no idea what a twelve-ring channel cage is. Second, while this is a language question, I figure the technical ability on the Science RD would be more valuable than the language parsing ability on the LRD. Third, thank you for any writing assistance you can provide! 61.189.63.185 (talk) 12:30, 24 August 2010 (UTC)

I would say "the pseudo-twelve-coordinate site in cancrinite". Cancrinite certainly has a pseudo-12C site (see here, and click on "Large pop-up" to see it more clearly), and Ca would be a better fit than Na. Physchim62 (talk) 16:06, 24 August 2010 (UTC)

Drunk

Can you get drunk from alcohol on tongue? Like if you just dipped your tongue into a cup of vodka but didn't drink. Would it diffuse into you? —Preceding unsigned comment added by Prize Winning Tomato (talk • contribs) 15:52, 24 August 2010 (UTC)

It would certainly diffuse into you. Whether it would do so faster than your body can process it (thus eventually rendering you drunk), I'm not sure. — Lomn 16:03, 24 August 2010 (UTC)

Maybe. This might be a fun experiment: hold a mouthful of ethanol-based (20 proof? 40 proof?) mouthwash in your mouth for a minute, rinse thoroughly, and then measure your blood alcohol content with those test strips or a breathalyser if you have access to one. I wonder if the uptake rate would vary much between individuals. Ginger Conspiracy (talk) 23:55, 24 August 2010 (UTC)

I don't think you can absorb much through the tongue, but you certainly can from under it, see: Sublingual administration. Ariel. (talk) 06:24, 25 August 2010 (UTC)

I think mythbusters did a show where they used mouthwash and then took a breathalyzer test and the BAC that the test showed would have been lethal to a human. Even after waiting for a significant period of time it was still showing highly elevated levels. Googlemeister (talk) 13:28, 25 August 2010 (UTC)

A breath-based alcohol measurement is likely to be very unreliable under those conditions. See Breathalyzer#Mouth alcohol, Breathalyzer#Products that interfere with testing. Trace amounts of alcohol residue in the oral cavity will badly skew the apparent alcohol content of breath. TenOfAllTrades(talk) 13:50, 25 August 2010 (UTC)

Light

Is light from a light bulb the same as natural sunlight? Or are there different types of light? Because well watered plants indoors with no sunlight tend to die —Preceding unsigned comment added by Prize Winning Tomato (talk • contribs) 15:54, 24 August 2010 (UTC)

You may be over-watering them - that makes the roots rot. The pot they are in needs to have drainage. There are many plants successfully grown as houseplants, so I am surprised, unless you truely mean zero natural light. Houseplants tend to get put next to windows. If over-watering is not the problem, then you could try plants that are adapted to deep shade, such as ferns. 92.15.13.237 (talk) 10:09, 26 August 2010 (UTC)

Light is made up of a spectrum of colours. Light from the sun will tend to have a different spectrum (that is, a different mix) of colours, than light from a bulb. Reading Grow light might be helpful - these are bulbs designed to produce a spectrum which is suited to nurturing plants. --Tagishsimon (talk) 16:01, 24 August 2010 (UTC)

No, yes. See colour temperature. 92.15.15.228 (talk) 18:04, 24 August 2010 (UTC)

Even if the spectrum (color temperature) of light is the same, the intensity is vastly different. Direct sunlight is about 100,000 lux, and a sunny day in the shade is over 10,000 lux. Even an overcast day is around 1,000 lux. In contrast, a typical living room is only 50 lux. That's over 1000 times dimmer than direct sunlight. We tend not to realize this because our eyes are so efficient at adapting to a wide range of light intensities. -- 140.142.20.229 (talk) 19:19, 24 August 2010 (UTC)

The comment above is correct, but as additional info, the light from an incandescent bulb is quite a bit redder than natural sunlight. However chlorophyll absorbs best in the red-yellow part of the spectrum, so the spectral difference wouldn't be harmful. It's the intensity that makes the difference. Looie496 (talk) 03:09, 25 August 2010 (UTC)

Light from a typical incandescent light bulb is more yellow, and at a lower color temperature, than sunlight, which is judged to be "white" light. You can purchase "daylight" bulbs, which have a blue filter coating more nearly approximating sunlight, though at a reduced efficiency. Light bulbs, whether yellow or daylight, incandescent or compact fluorescent or LED, emit electromagnetic radiation in the visible range, as does the sun, with varying efficacy. Edison (talk) 03:46, 25 August 2010 (UTC)

Try looking at your bulb (incandescent or compact fluorescent?) through a spectrometer. ~AH1 19:19, 26 August 2010 (UTC)

Milky Way Galaxy

What is the Milky Way galaxy made of?165.212.189.187 (talk) 15:58, 24 August 2010 (UTC)

Galaxies are made of stars and stellar byproducts, dust, and (probably) dark matter. Dark energy, as I understand it, is generally pervasive rather than clumped in galaxies. — Lomn 16:02, 24 August 2010 (UTC)

See also Milky Way#Composition and structure --Tagishsimon (talk) 16:04, 24 August 2010 (UTC)

There is a lot of speculation about dark matter these days; but it may turn out to be "uninteresting" cold hydrogen gas that just isn't warm enough to be incandescent. It may also turn out to be some form of exotic matter. Unfortunately (because it is dark and far away) we have few tools to study it directly. Nimur (talk) 19:56, 24 August 2010 (UTC)

Galaxies are made of "everything". A few hundred billion stars, a honking great black hole in the middle - and the dust, gas, moons, planets, asteroids and comets - but also people, trees, fish, elephants... When you come right down to it - it's hard to think of anything that a galaxy ISN'T made of! SteveBaker (talk) 23:37, 24 August 2010 (UTC)

... agreed, but galaxies contain only some (what proportion?) of the dark matter in the universe, and only a very small proportion of the dark energy (assuming that it exists). Dbfirs 08:20, 25 August 2010 (UTC)

Exactly my point, Steve. The Eentropy of Mixing is alive and well in all galaxies. —Preceding unsigned comment added by 165.212.189.187 (talk) 13:02, 25 August 2010 (UTC)

Don't forget about the nebulae and supermassive black hole. ~AH1 19:17, 26 August 2010 (UTC)

Why did some prick throw a brick into this washing machine?

What did he hope to accomplish? To solve? Why did this prick want to commit harm to it when he could've done good (or at least harm to something else) instead?

(And why was the washing machine smoking in the first place?)

http://www.youtube.com/watch?v=364dzVsBs2o

--70.179.165.170 (talk) 15:31, 24 August 2010 (UTC)

Are you seeking to accomplish or establish something by the repeated use of the idiom "prick"? To be honest, it merely rebounds onto you, leaving us to think that you may in fact be one. Why, for instance, could you not have "done good" and avoided the aggresive and unhelpful language. --Tagishsimon (talk) 16:22, 24 August 2010 (UTC)

A trip to your local dump / civic-amenity / recycling centre will reveal a horrid truth about modern society : we throw away a huge collection of manufactured goods that are defective but repairable, but that are nevertheless beyond economic repair. It's likely that this machine had such a defect - a bad controller card, a bad pump assembly, an agonisingly worn main bearing. If a new machine would be cheaper than the repair (which is very often the case) or the parts just aren't made (which seems to be very common indeed for machines older than a decade) then you end up having to chuck out something that otherwise still works. I'm guessing that's the case here (and may well explain the smoking). -- Finlay McWalter ☻ Talk 16:24, 24 August 2010 (UTC)

Concur. I was unable to get an old but high quality TV repaired simply because parts were no longer available. I was forced to take it to the local recycling centre. Exxolon (talk) 16:47, 24 August 2010 (UTC)

A friend at work had his 2 year old flat-screen TV start acting up. When he took it to get it repaired, the cost estimate was 70% of the original cost of the TV, and because flat screen TV's have gotten cheaper since then, that was about the same as the cost of a replacement (which had more features - better quality, etc). In light of that, it's not surprising that he was going to chuck it out. However, by searching for the model number and the fault condition online, I discovered that the problem was 90% certain to be one of the capacitors in the power supply. Within 10 minutes with nothing more than a torx-wrench and a soldering iron (and a bunch of generic capacitors that I had in my junk bin, probably recycled from something else that I'd pulled apart), I had the TV working again and saved the guy several hundred bucks - cost $0. Sadly, there doesn't seem to be a way out of this noose for the majority of the population. Even if you know it's a 10 cent part - very few people know how to use a soldering iron - and for some reason they don't realize that there a bajillion websites that explain how to use one. Whatever happened to "You aren't a 'real man' unless you have a garage full of tools and know how to use them"? SteveBaker (talk) 23:27, 24 August 2010 (UTC)

Was this yet another victim of the capacitor plague? It's surprising that the Taiwanese capacitor industry was penalized so greatly for doing something that made the manufacturers so much money... Wnt (talk) 22:54, 27 August 2010 (UTC)

To see what happens. Vimescarrot (talk) 16:29, 24 August 2010 (UTC)

Perhaps for entertainment. Lot's of people have spent a good deal more than the price of a used washing machine to make an entertaining youtube video.

There is no law that says that a person must devote every penny's worth of property they own to the betterment of mankind.

Craigslist tells me that the price of a damaged (notice that it's smoking) washing machine is about $100. Are you really berating this person for wasting the equivalent of two video game's worth of stuff? You've never spent $100 or more on entertainment?

(P.S. My favorite video of this kind is this one. Mostly because I wish I owned a hat like that.) APL (talk) 18:47, 24 August 2010 (UTC)

I agree: entertainment, curiosity, and the lurking lust for destruction. This is a good way of living it out. Not prickishness. There are also people who satisfy these needs by experimenting with or destroying what belongs to others (not just primitive vandalism of private or public property, also reckless experiments on college campus, for example). I agree with APL (though I admit I have my own personal limits of sensitivity toward destroying inanimate objects for show when it comes to food or musical instruments). In any event, it is likely that the smoking washing machine wasn't in mint condition, and even if it wasn't beyond repair, at least this was a creative and entertaining form of wastefulness. Didn't Letterman drop things from buildings for a while? ---Sluzzelin talk 19:00, 24 August 2010 (UTC)

How about asking the uploader? You might want to avoid calling them a prick though if you want an answer. Interestingly, that looks to be the same washing machine that I have. It's only a yearish old and it had a five year parts guarantee which does kinda make me wonder why they did it too. Smartse (talk) 13:54, 25 August 2010 (UTC)

Oh and this video is so much better and reinforced Vimescarrot's point. Smartse (talk) 13:58, 25 August 2010 (UTC)

"Will it Blend" are paid advertisements for blenders. So they don't really demonstrate honest curiosity. APL (talk) 14:50, 25 August 2010 (UTC)

I feel sorry for it :( 82.44.54.25 (talk) 14:09, 25 August 2010 (UTC)

The difference between sacrifice and blasphemy (picture and video) ? Cuddlyable3 (talk) 19:08, 26 August 2010 (UTC)

7 degrees of separation

Most people know the old adage, "You're only 7 people away from knowing everyone in the world?" What is the etiology of this? Have there ever been any well-controlled studies about it? Are the scholars (philosophers, sociologists etc.) who've focused a great deal of time looking into it's supposed validity? Are there any good books about it? Buddpaul (talk) 17:48, 24 August 2010 (UTC)

Six degrees of separation has a lot of information. -- Finlay McWalter ☻ Talk 17:54, 24 August 2010 (UTC)

It's certainly not a cast iron RULE. There are undoubtedly people who can't be reached in so few steps. But it is an exceedingly solid average. There was a rather good Discovery channel documentary on this - which they tested by picking a bunch of people around the world and asked them to get a message to a specific US researcher by passing it on to someone they knew - amazingly, they all managed to get the message to it's destination - and in each case, within the six degrees. There is a significant body of mathematics that show why this is true - and it has applicability to all sorts of systems. For example, you can almost always get from your computer to any other on the Internet by routing the message through about six other computers.

The game "Six degrees of Kevin Bacon" requires you to find a chain of actors, producers or directors who are linked to Kevin Bacon by participating in movies that link them along the way. (eg Elvis Presley was in Change of Habit (1969) with Edward Asner who was in JFK (1991) with Kevin Bacon) - someone who studied the Internet Movie Database (IMDB) discovered that of the 1.6 million people listed there, only 150 of them could not be connected to Kevin Bacon in 6 steps or less. However, we're restricting them to being connected only by movies they've participated in - if we were allowed to connect them by friends, aquaintances, neighbors, co-workers, etc - I'm sure the paths would be much shorter.

An experiment on Facebook connects friends of friends of friends...it finds that the average number of friend links to get from anyone to anyone else is 5.7...again, less than 6 degrees. There have even been experiments right here in Misplaced Pages to see what the fewest number of links you have to click on to get from any article to any other...and again, the answer is less than 6.

The result is so ubiquitous across so many fields that it starts to seem like a rather fundamental result.

SteveBaker (talk) 22:43, 24 August 2010 (UTC)

Wow, I had no idea there was an Erdős–Bacon number, let alone an article on it! ---Sluzzelin talk 04:17, 25 August 2010 (UTC)

Has there been any research done on this subject in the context of sexual partners? For instance HIV/AIDS presumably started with one individual and has now spread to very large numbers worldwide, implying that there is a very large network of people linked by sexual contact. I wonder how many links there would be on this network between random people. The network is of course much larger than the HIV/AIDS numbers by themselves suggest, given that the probability of catching it from an infected person is well less than 1. --rossb (talk) 14:11, 25 August 2010 (UTC)

The experiment on Facebook showed that the largest separation number among participants was 12, although a user could easily have friends they don't know or not have someone on Facebook who they do know. ~AH1 19:16, 26 August 2010 (UTC)

Common Descent

What are the odds that we are actually descended from the particular, specific fossils we've found in Africa like Lucy? What if she had no children herself? Is there any way to prove we're directly descended from a fossil and not one of their siblings? TheFutureAwaits (talk) 19:00, 24 August 2010 (UTC)

The only way to do that would be by means of archaeogenetics. The "Ancient DNA" article only mentions this technique having been applied as far back as eg. "Ötzi the Iceman" and the Ancient Egyptian mummies -- ie., maybe five or six thousand years, nowhere near the 3 or so million years ago for the "Lucy" remains!

So much for "proof." As to odds, those will depend on things like the population size and distribution, etc., of contemporary Australopithecus afarensis and I will leave it for others to try to estimate those if they can... Wikiscient (talk) 19:19, 24 August 2010 (UTC)

You might also want to consider the information in the Mitochondrial Eve article, though I'm not sure this is going to address the specific question you seem to be asking. Wikiscient (talk) 19:23, 24 August 2010 (UTC)

If you are asking about the probability of a specific early fossil being an ancestor of you, personally - then the odds are surprisingly high. Someone who lived just 30 generations ago (600 years - in about the 1400's) would by now have over a billion descendants. Several estimates say that someone who lived in the 6th century BC could easily be the ancestor of everyone alive today - other estimates put it MUCH more recently than that (unless you happen to be a native of the Amazon basin or something equally out of the way). The most recent ancestor of all people of European descent probably lived less than 1000 years ago.

Our Most recent common ancestor article is worth reading.

The most likely chance for a fossil (rather than just a rather old skeleton) would be a fossil from about 70,000 years ago when human population crashed (according to the Toba catastrophe theory) to less than 10,000 individuals - perhaps only 1,000 breeding pairs. The La Ferrassie 1 fossil is about that old - and is highly likely to be your ancestor.

Back at 1.2 million years ago, there were around 26,000 people in the world - and that number is probably fairly constant all the way back to the time of Lucy (3.2 million years ago).

The difficulty is that beyond a few thousand years ago, the issue isn't so much whether you, personally, are descended from a particular individual - the question is whether ANY of that person's offspring survived. If they had a blood line continuing for more than a handful of generations, then the odds are extremely high that you are a descendent - but obviously if that person had no children, or those children all died before child-bearing age - then the odds are zero.

That means that the odds are all about the number of surviving children from each generation that made it through to child-bearing age back at the time of the fossil you're thinking about. I don't think we have a clue about how many children a Lucy-era Australopithecus would have had - let alone how many would have survived - so it's tough to know whether we are all likely to be ancestors of Lucy or not...maybe she died childless...maybe she bore a dozen healthy kids who all gave her a bunch of grandchildren - if that's what happened, then she is an ancestor of all of us.

SteveBaker (talk) 22:18, 24 August 2010 (UTC)

There is only one way, in principle, to prove descent from a specific individual from long ago -- that's if the individual had a novel genetic mutation that was not present in either parent, and is present in you. The odds of ever being able to prove that for an ancient individual are extremely slim, with emphasis on extremely. Looie496 (talk) 03:03, 25 August 2010 (UTC)

Add to the above the (slim, but nonzero) probability that the specific fossilized individual was a part of a monozygotic multiple birth, and it becomes impossible to prove that they were your direct ancestor. -- Scray (talk) 04:38, 25 August 2010 (UTC)

Searching for fossils by radar

How come this hasn't taken off? It sure seems easier than digging blind! http://www.americanscientist.org/issues/pub/2001/1/fossil-hunting-by-radar TheFutureAwaits (talk) 19:05, 24 August 2010 (UTC)

Radar has limited penetration through rock or soil except where conductivity is low - dry sand is ideal, anywhere that is wet (particularly if at all saline) or consists of mainly clay for instance would yield far less useful data. I don't suppose that this sort of thing comes cheap either, any group would need to be well-funded. I see that the article linked to is nine years old, maybe they couldn't either raise the funding or the results of the pilot project were not that good. Mikenorton (talk) 19:24, 24 August 2010 (UTC)

Geophysical survey (archaeology) has some nice links and photos. For archaeology, the advantage is that human artifacts tend to be near the surface (not very deep) and are often metal or highly contrasting material to the surrounding overburden. With more ancient fossils (like dinosaur bones, for example), RADAR penetration and reflectivity contrast is not very good. Nimur (talk) 20:10, 24 August 2010 (UTC)

I would expect the main problem is false positives. You're going to get hugely noisy signals. Looking at something comparable, take a look at the kinds of things you get from side scan sonar. For every photo like this, where you can tell pretty well what it is, you get millions like this, or this, or this, or this. (And THOSE are probably chosen as the most illustrative of their own surveys!) Now imagine that instead of just going sideways in the ocean looking for solid structures on the surface, you are actually looking down into the rock and so on of the last few thousand (if not millions) years of history. You get images like this. What is that? It turns out it is a cemetery. (Using Ground-penetrating radar.) Is getting a survey like that likely to be useful, or is it going to send you off on a thousand false positives, thinking you've found a cemetery (or dinosaur, or whatever), and instead finding a bunch of buried parts from an industrial factory, or some odd shaped rocks, or whatever else is underground? This is just my hunch but I'd think that such a thing would be a pretty difficult endeavor. --Mr.98 (talk) 00:37, 25 August 2010 (UTC)

Mineralization converts fossils to the same material as the surrounding rock, more or less; more often no sign of their presence remains at all. I think even fresh biological materials buried in rock would be very difficult to find by ground penetrating radar, even before being tightly compressed, unless quite large voids are present. Wnt (talk) 04:40, 25 August 2010 (UTC)

motors

Are electric motors and dynamos the same thing? So for example I could take the motor from a fan and put it on my bicycle and it'd power the light? Or are they different —Preceding unsigned comment added by Prize Winning Tomato (talk • contribs) 20:04, 24 August 2010 (UTC)

DC motors containing a permanent magnet can generate electricity when rotated, just like a dynamo. Electric motors not containing a permanent magnet need a more complicated mechanism to produce electricity. Dynamos are specialized for their use though, so they probably generate a higher voltage than electric motors would. --Chemicalinterest (talk) 20:24, 24 August 2010 (UTC)

Talking of motors, I too raise my hand. I have a DC motor with permanent magnet. It works well on 3 volts, but does not work on 9 volts DC or more. why ?  Jon Ascton  (talk) 01:10, 25 August 2010 (UTC)

Back in the 1860's they realized that generators and motors were basically the same things. But if you take a motor from a fan, and it was previously powered by 120 v AC (US) or 240 v AV (most of the rest of the world) it will not generate appreciable voltage when you spin the rotor,unless the stator is energized at the correct voltage and phase. If you devise and implement a way to have the field (stator) energized correctly while you cause the rotor to spin, you could use the motor as a generator. Direct current machinery is probably easier to use in this way than alternating current machinery. Edison (talk) 03:40, 25 August 2010 (UTC)

One cool demo I do a lot for people is to take a couple of simple DC motors (two Lego Technics motors work well because they have internal reduction gearing) and connect them together - no batteries, no switches, nothing but a couple of feet of wire. It is really spooky that you can turn one motor (thereby making it be a 'generator') and see the other precisely mimic its motion (well, precisely - minus a bit of inefficiency along the way...but remarkably little) - even though they are a couple of feet apart. You turn one a quarter turn, the other one turns a quarter turn...you turn the second one a quarter turn back to where it was - and the first one obediently mimics it. Even when you know what's going on, it's really quite freaky! SteveBaker (talk) 04:48, 25 August 2010 (UTC)

Thanks for that. I once saw that demo performed but I thought the two devices must be specially constructed for the purpose. I didn't realise it would happen with any old pair of DC motors! Dolphin (t) 08:23, 25 August 2010 (UTC)

I think it may be important to a really convincing demo that the motors have internal gearing - you have to generate enough current in the 'dynamo' motor to overcome stiction in the other or it won't move at all. If the motor isn't geared then you might have to spin the shaft more rapidly than you can easily do with your fingers to generate enough current. The Lego motors that I use have a 16:1 reduction gear inside - so by gently rotating the output shaft, you're spinning the actual motor 16 times faster. Having said that, I managed to get the effect to work well enough with two of the tiny motors they use to make cellphones vibrate...so it may not be so difficult without gearing. SteveBaker (talk) 15:47, 25 August 2010 (UTC)

One of the simplest physical principles that I've never understood is the idea of self-excitation of a dynamo such as those invented by Ányos Jedlik. I just don't understand how the current gets started. But I suppose such a device must be as reversible as any other motor. Wnt (talk) 13:59, 25 August 2010 (UTC)

It might be noted that on many railways the fact that the same device can be a motor and a generator is used in an important way. See dynamic braking for diesel-electric trains, and regenerative braking for electric ones, where slowing down one train can help power another (or even help power things off the railway). --Anonymous, 22:26 UTC, August 27, 2010.

Human IQ

a) How long ago was it when the IQ of human ancestors was equal to the IQ of contemporary chimps? b) Why do humans have so much surplus IQ? Surely evolutionary speaking we just need enough IQ to feed and reproduce, but not to deduce that E=mc^2? How or why did this surplus IQ evolve? c) If in a population the less intelligent parents have more children that average, could this reduce the average IQ of the population? How many generations would it take? Is there any indication that this may be happening currently? Thanks 92.15.3.135 (talk) 20:10, 24 August 2010 (UTC)

I really don't know how applicable IQ tests are to animals. There is a fair amount of bias in IQ tests between human cultures, let alone non-humans. Googlemeister (talk) 20:18, 24 August 2010 (UTC)

(ec) There is not an easy answer to any of these questions. You can start by reading Evolution of human intelligence and theories of human intelligence. It is not even clear how to measure and compare "average" intelligence between different people in the same era, let alone through multiple decades, centuries, or so distant into the past that evolutionary biology becomes the dominant factor. It will be hard to give an exact historic timeframe for when we became "smarter" than chimpanzee, but human evolution discusses this well. Sapiens, or "wise human", is the name commonly given to those first fossil hominids that we identify as "modern" and "intelligent" - and they appeared around a half-million years ago - but understand that this transition toward "intelligence" occurred over a wide swath of the timeline and our best fossil evidence is "size of skull" as an indicator of intellect. Other evidence, such as behavior, lifestyle, toolmaking, and so on (things we would consider the hallmarks of "intelligence") are largely inferred from indirect evidence as we go deep into prehistory hundreds of thousands of years back - so exact dates are impossible to proscribe. Regarding the evolution of additional intelligence, beyond the basic need for survival - I would call this a sort of "evolutionary inertia." We may have evolved "merely to survive," but as a side effect, we proliferated and thrived - because conditions were good enough, and we became the apex predator. Intelligence has helped humans to maintain their position as apex predator, and the rise of civilization throws much complexity into the simplistic view of straightforward natural selection. The definition of "fit enough to survive and reproduce" significantly changed as humans began to make easy work out of "basic survival." In light of this, even your last question is not easy to answer; you might also want to consider the nature versus nurture debate. Modern intelligence is a plethora of different skills - innate and learned - so it is not even safe to say with certainty that "dim" parents will produce "dim" progeny. Nimur (talk) 20:26, 24 August 2010 (UTC)

a) I think you mean "intelligence" here much more informally than its rigorous definition according to "IQ". You can't give an IQ test to a chimp. So the answer is that humans started developing "human intelligence" as soon as human ancestors and chimp ancestors parted ways evolutionarily (which was as long ago as maybe 15 million years depending on how you look at it).

b) Again I think you are wondering about surplus "intelligence" and not "IQ" per se. One thing to consider is that this intelligence, informally speaking, is in large part due to cultural development. Einstein could derive "E=mc" only because he lived at a time when the math and physics he used to do so had been sufficiently developed. As the theory goes, he could have been born a million years earlier and still have been as "capable" of developing his theories as he was a hundred years ago -- had he simply had the same cultural tools available to him a million years ago. (For more on how this could be, see eg. "exaptation" (= "using a trait for some purpose other than that for which it evolved") and "positive feedback loops" and etc.)

c) According to the Fertility and intelligence article, there are indeed indications that "this" may be happening currently in some ways. But I expect it would take much, much longer than that trend is likely to last (even if that turns out to be hundreds or even thousands of years) for Homo sapiens to evolve a "genetically" "lower IQ."

Wikiscient (talk) 21:10, 24 August 2010 (UTC)

You may enjoy the novel Galapagos, by Kurt Vonnegut, which is told from a viewpoint a million years in the future, and which postulates that the big brains of today's humans has been one big evolutionary mistake; humans end up evolving into creatures with much smaller brains, able to swim in the water and catch fish as seals do, but without the predilection or even the capacity to create nations or war or mass environmental destruction. Comet Tuttle (talk) 21:31, 24 August 2010 (UTC)

I don't think that the assumption that "we have IQ to spare" makes a lot of sense. We (more or less) agree that IQ isn't about memory capacity - in computer terms, it's more like "CPU speed" than "RAM size". That being the case, you don't "run out of IQ" like you might run out of memory. You might need a certain amount of brain power to conceive of the shape of a stone arrowhead and to figure out how to knap that from a large flint rock - or to figure out how deer behave when you encircle them in a particular way at a particular time of day when they are not near a water supply and have calves with them at the time. That's probably not much different from the amount of "CPU power" it takes to figure out E=mc. When people are thinking hard about problems like that, they tend to need quiet, no distractions, not to be doing anything else at the time - which suggests that we're using close to the full amount of CPU power that we have available.

There just isn't any evidence that we're smarter than our homo-sapiens ancestors. Einstein didn't come up with E=mc just from nothing - he needed the results of experiments - the benefits of prior thinking from the likes of Newton. He needed writing and printing and mass-production and the ability to have a job that allowed him to spend long periods without distraction without having to (say) search for drinking water or make a fire or...whatever. We can do what we do because our brains aren't being used for a whole bunch of other things that we'd be using it for if we didn't have all of the benefits of modern civilisation...not because we're smarter than the cavemen. Obviously, there was a time when we weren't this smart - and looking back at fossil hominid skulls would probably allow us to guess when our brain size started to get bigger than that of modern chimpanzees. So we have obviously been getting smarter - but never smarter than was necessary in order to thrive in the environment of the time.

SteveBaker (talk) 21:36, 24 August 2010 (UTC)

Re. your first paragraph: this is basically what I'm saying about "exaptation" above.

For example: consider alexia, the neurological condition of having very specifically lost the ability to read only (ie., no other visual impairment, etc) due to damage to specific parts of the occipitoparietal region of the brain. So reading (an aspect of "intelligence" as the term is being used informally here) is a specialized, hard-wired, phenotypical trait of the human brain.

Reading has been around for a few thousand years. Have our brains evolved such a complex ability that quickly? No. Then why have we been carrying around a "reading gene" without using it for a million years or so?

As Oliver Sacks wrote a couple of months ago:

"Writing, a cultural tool, has evolved to make use of the inferotemporal neurons’ preference for certain shapes. The origin of writing and reading cannot be understood as a direct evolutionary adaptation. It is dependent on the plasticity of the brain, and on the fact that experience is as powerful an agent of change as natural selection. We are literate not by virtue of a divine intervention but through a cultural invention and a cultural selection that make a creative new use of a preëxisting neural proclivity."

"Intelliegence" is all like that! :) Wikiscient (talk) 22:25, 24 August 2010 (UTC)

The question (which I doubt has been researched) is whether someone with alexia is still able to understand the meaning of cave paintings - and track animals by 'reading' their footprints. I very much doubt that such a study has been done - but I'd bet good money that they'd find other somewhat-related abilities were also lacking. The difficulty in doing such a study is that not many humans still have the ability to "read" cave paintings or footprints (or whatever it is that this part of the brain actually evolved for doing) - so the probability of someone with one of those abilities also contracting alexia and being studied in great detail afterwards is vanishingly small. SteveBaker (talk) 04:39, 25 August 2010 (UTC)

Nobody knows what IQ even measures.--92.251.132.249 (talk) 22:30, 24 August 2010 (UTC)

Well, that's not really very true. There are entire disciplines of psychology dedicated to the study of intelligence quotient and standardized testing - the people who design and analyze these tests are very sure they know what they are measuring. And though individual performance may vary due to statistical outliers, there is absolutely no doubt at all that when measured across large populations, IQ strongly correlates to things like salary, mortality-rate, performance on Army rifle-range scores, dental hygiene, and so on - the number of things that IQ positively correlates to is actually quite striking. Correlation does not imply causation. But standardized tests definitely measure things like the ability to focus; the ability to think clearly; and the ability to reason through difficult problems. Modern tests also go to great lengths to eliminate cultural, language, and educational background biases. So, while it may be fair to claim that "many people do not know how to properly interpret the meaning of an IQ or other standardized intelligence metric," it is completely incorrect to say that "nobody knows what IQ measures." Nimur (talk) 23:37, 24 August 2010 (UTC)

Getting off-topic, but see also: What is Intelligence? Wikiscient (talk) 00:20, 25 August 2010 (UTC)

You're making a number of presumptuous assumptions. First off, you would have to define exactly what it is your measuring in your IQ test. The you would have to balance the test, which across species would lead to an inherent bias due to a lack of understanding/misinterpretation. See Stanford-Binet Intelligence Scales.Smallman12q (talk) 01:40, 25 August 2010 (UTC)

I always thought that human intellingence resulted from sexual selection, but I don't have any reference. --Lgriot (talk) 13:46, 25 August 2010 (UTC)

Perhaps in our early ancestors sadly there was a lot of fighting and manipulation over mates, so to reproduce you needed to be smarter and stronger than your rivals. This might explain gender dimorphism. 92.15.13.237 (talk) 10:16, 26 August 2010 (UTC)

See Darwin Awards. Also the pressures of complex human society require intelligence to survive it, and it was especially needed after the move from hunter gatherer to agriculture. People who only recently by ancestry were hunter gatherers have problems with success in society and unrelated to IQ they also have problems with eating foods not of the paleolithic diet (e.g. cow milk, legumes, grains, etc.) Are you ready for IPv6? (talk) 01:55, 28 August 2010 (UTC)

Floating Metal Ships

Ships made of metal with a density greater than that of water float because they are not entirely made of that metal and much of the volume will be taken up by air, whose density is clearly less than that of water. I think this principle has a specific name but can't for the life of me remember. Anyone have any ideas? Thanks asyndeton talk 21:23, 24 August 2010 (UTC)

Are you just looking for the term "Buoyancy"? Wikiscient (talk) 21:27, 24 August 2010 (UTC)

Archimedes principle. Mikenorton (talk) 21:42, 24 August 2010 (UTC)

Have you thought about an airtight vessel made of metal with a density greater than that of water, but not full of air, infact it is full of nothingness, but still it will float ! What do you say to that ?  Jon Ascton  (talk) 00:31, 25 August 2010 (UTC)

${\displaystyle \rho _{metal+nothing}={\frac {m_{metal}+0}{V}}\ \approx \rho _{metal+air}}$

Wikiscient (talk) 00:52, 25 August 2010 (UTC)

There is a classic schoolroom demonstration, in which a (lightly oiled) razor blade is floated on water, because the surface tension of the water prevents it from wetting the blade, which hence maintains the air needed for buoyancy above itself. Though I suppose a modern American school would expel anyone for attempting such a demonstration, lest they seize the blade and have a massacre. Wnt (talk) 04:33, 25 August 2010 (UTC)

Or you can avoid controversy, focus on the science, and float a paperclip. Nimur (talk) 19:25, 31 January 2011 (UTC)

Medical doctor specialties

Medical doctors often specialize ... for example, a cardiologist is a heart doctor and an oncologist is a cancer doctor (etc.). What type of doctor would I see if I were interested in weight loss? I don't mean as a morbidly obese person ... but just as a regular person trying to lose 10 or 20 pounds. Is there a medical specialty for weight loss? I'd rather not see a general practitioner, as they probably know no more than I do about weight loss ... or they can only tell me in general terms what I could probably find for myself in a book or on the internet. Thanks. (64.252.34.115 (talk) 21:34, 24 August 2010 (UTC))

Dietician? Clarityfiend (talk) 22:26, 24 August 2010 (UTC)

A nutritionist or a dietitian is a specialist, but not a doctor. Check carefully - these terms have significantly different meanings in different regions; in some places, there are no requirements, training, or licensing of any kind to be called a "nutritionist"; while in other regions, these terms are regulated and can only be used by trained professionals. It is rare to find a person of either specialty who is also a medical doctor, though. Nimur (talk) 22:28, 24 August 2010 (UTC)

Thanks. Then what type of medical doctor handles obesity? Thanks. (64.252.34.115 (talk) 03:34, 25 August 2010 (UTC))

In the USA, internists (those who have trained in Internal Medicine) have a strong interest in managing obesity. Their professional organization, the American College of Physicians (ACP) has a web page for patients and families about obesity, illustrating this interest. A similar role is embraced by family practitioners , gynecologists , and pediatricians . Basically, primary care practitioners. -- Scray (talk) 04:31, 25 August 2010 (UTC)

Maybe a gastroenterologist? Especially if you're after gastric surgery. --TammyMoet (talk) 08:13, 25 August 2010 (UTC)

Also see weight loss and Obesity#Management.Though be aware Misplaced Pages doesn't give medical advice.Smallman12q (talk) 12:32, 25 August 2010 (UTC)

A bariatrician. --Sean 15:00, 25 August 2010 (UTC)

Unidentified moving blob in a sewer

http://www.youtube.com/watch?v=ELoqZiamr4E

what is that? Is it some kind of bacterial colony? Perhaps some kind of colony like a portugese man-o-war? Something fake?--92.251.132.249 (talk) 22:29, 24 August 2010 (UTC)

According to Dr. Timothy Wood, "They are clumps of annelid worms, almost certainly tubificids (Naididae, probably genus Tubifex). Normally these occur in soil and sediment, especially at the bottom and edges of polluted streams. In the photo they have apparently entered a pipeline somehow, and in the absence of soil they are coiling around each other. The contractions you see are the result of a single worm contracting and then stimulating all the others to do the same almost simultaneously, so it looks like a single big muscle contracting." This information is according to this article. — GorillaWarfare 22:42, 24 August 2010 (UTC)

See Tubifex tubifex. Ghmyrtle (talk) 22:46, 24 August 2010 (UTC)

This question has already been asked. ~AH1 19:12, 26 August 2010 (UTC)

Hah! As soon as I saw the title for this question, I knew it would be the same clip I'd asked about earlier. Matt Deres (talk) 18:19, 28 August 2010 (UTC)

Top soil and a layer of clay

I've been turning over the soil in the back yard a couple of days ago -- a fairly heavy clay-rich soil -- and the following has occurred to me. I always turn the soil about one spade deep; say, 10-15 inches. What then prevents the smallest mineral particles in the soil from being washed down and forming a watertight layer of clay at the depth of about 15 inches? Or does this really happen? I guess the earthworms can burrow deeper than that, so it's not completely watertight, but still, does this really happen? And is there something I'm supposed to do for this not to happen? --Dr Dima (talk) 22:30, 24 August 2010 (UTC)

Yes, if you get a hardpan clay subsoil layer that won't drain, you have a few options. You can plow it or otherwise mechanically mix in the soil or you can plant something with really aggressive roots at the layer involved (alfalfa?) or ideally both.

These kinds of agriculture questions depend heavily on your locale, geology, and climate. When I was a kid, whenever such questions would come on the USDA-run write-in radio program for farmers (why the heck was I listening to that? I must have been a really weird kid) the announcer would always say something like "consult your local university, college, or community college agriculture outreach program" which is probably pretty good advice for any gardeners who are facing those kind of problems. There might be some obscure plant that loves the kind of clay you get so much that just a little bit with a lot of water will tear it all up with roots and turn it into draining, fertile soil for tubers or whatever you want. Ginger Conspiracy (talk) 23:29, 24 August 2010 (UTC)

The problem certainly occurs at an agricultural scale, which is why clay rich soils need artificial drainage – in Holland, they even used windmills to pump the water out of the drainage ditches. At the back yard scale, there's little you can do in practice except to keep the top layer healthy, unless you have somewhere convenient to dump any excess water. Large plants with deep roots around the edge of the yard will help, but a lot depends on the size of the yard as well. Physchim62 (talk) 23:43, 24 August 2010 (UTC)

Pumps are needed in Holland becauise much of the land is below sea-level. Darwin studied how earthworms mix up the soil. See Earthworm#Locomotion_and_importance_to_soil and also the subsequent Benefits section. 92.24.186.119 (talk) 13:11, 25 August 2010 (UTC)

You might also be concerned about soil compaction. ~AH1 19:09, 26 August 2010 (UTC)

August 25

Growing Tree

A tree is growing. I am 3 feet tall. I stand near the tree and just at near where my head-top corresponds to the tree, i.e. at 3 feet from the ground level, I make a mark of adequate depth that (let's suppose ) will last forever. The tree will grow. What will happen to the mark ? Will it's distance from the ground increase as it will grow  Jon Ascton  (talk) 01:02, 25 August 2010 (UTC)

No. Trees (and almost all plants) grow from the top. Grass grows from the bottom though. Ariel. (talk) 02:13, 25 August 2010 (UTC)

I don't think this is completely right. There is a Birch tree which I used to easily climb when I was a kid at my dad's house. 40 years ago I could reach my leg up and step into the first fork, despite being 10 years old and shorter than I am now. The tree seems to have grown in all proportions, it is now much thicker, much taller and the fork is just above shoulder height. -- ~~

Trees grow both upwards and in diameter. The layer of wood immediately under the bark is the sapwood or living wood. This reference describes the growth process and concludes that the height of a bird-house fixed to the trunk will not increase as the tree grows. Cuddlyable3 (talk) 12:33, 25 August 2010 (UTC)

I will try to get some photos, the fork is definitely much higher from the ground than it was years ago. -- Q Chris (talk) 13:49, 25 August 2010 (UTC)

I think it depends on the age of the tree, if you did it to a sapling then it might move up, I doubt it would happen on a mature tree though. Part of the reason is that botanists measure trees at 1.3m above the ground (diameter at breast height) and if they are studying how fast they are growing will add a line of paint to the tree to speed things up next time round. Q Chris - is it possible that the fork you remember climbing has died/been cut off and isn't the same one you see now? Smartse (talk) 14:10, 25 August 2010 (UTC)

There might be a simple explanation: What you call fork is probably the meeting point of the bark of two upleading branches. That means your original forkpoint is now deeply embedded into the stem, the current fork point is the meeting point of new layers of material. Try to imagine what happens when you surround all existing bark with further layers. And try to follow in mind the middle line of the branches to the point where they meet. -- Tomdo08 (talk) 14:19, 29 August 2010 (UTC)

Well, I just consulted my mom who belongs to countryside and spent her childhood among trees. She says she once marked a tree for it's fruit and though the tree grew high with time, but the marking she made did remain at same level  Jon Ascton  (talk) 06:21, 26 August 2010 (UTC)

Getting an old scientific article - how?

Hi, I would like to read the article "Thinking about the brain" from Francis Crick, which was published in 1979 in the Scientific American of September (241 (3), p.181-188). Is it possible to get that article easy and for free? The licence of my library seems only to reach back till 1984. -- 89.196.35.247 (talk) 02:38, 25 August 2010 (UTC)

Usually Google Scholar is the best bet for things like this, but it shows no online versions, not even non-free. Have you tried looking for hard copies of Scientific American from that era in your library? Looie496 (talk) 02:59, 25 August 2010 (UTC)

Copies from 1979 should be readily available. I suggest you go to your library and ask about inter-library loans. Most libraries are happy to arrange inter-library loans. It is part of their function. Dolphin (t) 03:01, 25 August 2010 (UTC)

Ok, I'll try. Thx for the answers. -- 89.196.35.247 (talk) 09:05, 25 August 2010 (UTC)

Or ask at Misplaced Pages:WikiProject_Resource_Exchange/Resource_Request and some kind person will make a copy available to you. Smartse (talk) 14:12, 25 August 2010 (UTC)

I got the great idea, to just look at the german version. This one is available at my library and also online. I also asked about inter-library loans, but that was complicated and costs some money. Thx for the help anyway. Won't be the last time I need such articles, Resource Request is also a great hint! -- 141.30.81.231 (talk) 01:15, 27 August 2010 (UTC)

Double check my work?

The question reads as "If a current of 40mA exists for 0.8min, how many coulombs of charge have passed through the wire?" Given that, I used

${\displaystyle .04=(x/48)}$

I got an answer of 1.92 coulombs but the book says 192. Who's right? And if it's the book, why? Dismas| 05:46, 25 August 2010 (UTC)

I also get 1.92 Coulomb. Typing error? Dolphin (t) 07:15, 25 August 2010 (UTC)

Thanks! Dismas| 07:55, 25 August 2010 (UTC)

192 cC or centicoulombs. Cuddlyable3 (talk) 11:17, 25 August 2010 (UTC)

This thread is a bit old, but generally dimensional analysis can increase your confidence in solutions to these sorts of problems. In particular, 1 ampere = 1 columb / second. 67.119.3.248 (talk) 19:16, 30 August 2010 (UTC)

Anesthesia causing nerve damage?

Bear with me here, I have a Chinese co-worker whose wife just had all four of her wisdom teeth out. Apparently this was done with only a little bit of local anesthetic and with the patient fully aware, and in fact sobbing in agony, throughout the procedure. I was horrified. My Chinese friend laughed it off and said that "Chinese people don't use anesthetic because it can cause nerve damage." He seems quite confident in this position, seeing as how his mother is the managing director of a local hospital. I, on the other hand, call bullshit. Thinking critically, I think the likely absence of anesthetic in many parts of post-WW2 China had to be justified somehow, and once cultural acceptance set in the authorities have seen no real motivation to change, despite the modern widespread availability of anesthetics.

I've experienced this reticence to prescribe pain-relievers personally, by the way, when I broke my arm here last year and they were quite shocked by my request for pain-killers after having had my arm set and casted. "You want what? Haha! Silly foreigners aren't as tough as Chinese!" Anyway, back to the original question - has China picked nerve damage as the one aspect of human quality of life out of thousands that they actually care about (ignoring things like air quality, noise pollution, smoking, etc) ? or is this just BS? 218.25.32.210 (talk) 07:46, 25 August 2010 (UTC)

The article Traditional Chinese medicine will be of interest because it is still practiced alongside western medicine. Acupuncture is used for pain relief in TCM which may explain a slowness to accept Western pharmaceuticals such as pain-killers. Cuddlyable3 (talk) 11:14, 25 August 2010 (UTC)

It's not complete bullshit, but it's pretty rare. See Local anesthetic#Undesired effects for more information. Regards, --—Cyclonenim | Chat  12:35, 25 August 2010 (UTC)

In my experience, Chinese people can have some weird ideas on what is and is not safe. I knew a Chinese guy who would not stand within 20 feet of a running microwave because he thought he would get cancer, but he was perfectly fine with smoking. Googlemeister (talk) 13:17, 25 August 2010 (UTC)

Lignocaine#Adverse_drug_reactions has some specifics on a dental anaesthetic which can cause nerve damage. Making assertions from your friend and one doctor to the 1.2 1.4 billion people in the PRC might be a mistake though. Smartse (talk) 14:05, 25 August 2010 (UTC)

(ec)In my experience, Wikipedians can have some pretty offensive ideas about when it is appropriate to draw conclusions about an entire country or ethnic group based on anecdotal information. I knew a Caucasian Canadian woman who wouldn't let grocery store clerks use a bar code scanner on her food because it was "radiation". On the other hand, I haven't met any Chinese people who hold that particular damn-fool belief; I therefore conclude that it's Caucasians – or maybe it's Canadians? – who have 'weird ideas on what is and is not safe'.

Seriously, the Reference Desk is not the place to parade your own personal stereotypes. If you want to talk about what this or that people believe, then use real numbers, from properly-vetted studies. And I note that in the United States, recent studies have found that between half and two-thirds of all Americans believe in angels; a significantly larger fraction than believe the scientific consensus on global warming (about one third). Who's got the 'weird ideas', again? TenOfAllTrades(talk) 14:08, 25 August 2010 (UTC)

I have no direct knowledge of the Chinese culture, but bear in mind that the country faced a long and extraordinary enslavement to opium as the result of more than two centuries of drug prohibition, which according to some was only fully extirpated in Maoist times under the severest coercion. I would not be so surprised if a cultural imprint remains. Speaking as someone who has rejected several overtures by dentists to remove healthy third molars, I think her ordeal may well have been doubly unnecessary. Wnt (talk) 14:09, 25 August 2010 (UTC)

It is possible for there to be temporary (or, very seldom, lasting) damage to nerves simply due to the injection of local anesthetic — the needle may touch or pass directly through the nerve when administering the nerve block, though usually even this does little or no harm. More common is damage to the nerve caused by the extraction itself; damage to the lingual nerve may result when the roots of the wisdom teeth are particularly close to the nerve. This summary is brief, and quite accessible. See also Dental extraction#Complications. TenOfAllTrades(talk) 14:27, 25 August 2010 (UTC)

Damage to the lingual nerve is rare as a result of wisdom tooth root proximity -- this is because the lingual nerve does not enter the mandible (as does the inferior alveolar nerve) but rather courses medially to the body of the mandible. The lingual nerve does exist in superficial soft tissue, but danger to it is likely to occur as a result of an ill-placed incision during surgical extraction of the lower wisdom teeth, regardless of root position. There is a very little bit of supportive literature for danger to the mandibular segment of the trigeminal nerve following the administration of articaine, but this was in a pediatric patient and the reported incidence (depending on whether or not you include one of the instances based on extenuating circumstance) was either 1:100,000 cases or 2:100,000 (1:50,000). So the rate of irreversible damage to the mandibular branch of the nerve due to nerve blocks using articaine is taught as 1 in 50K to 1 in 100K. Still, since articaine is no more efficacious than lidocaine or mepivacaine in respect to mandibular nerve blocks, many dentists opt to not use articaine for blocks. DRosenbach 19:25, 25 August 2010 (UTC)

As an additional anecdote, I got 4 baby teeth pulled in two separate operations in a PRC hospital when I was 7, and a fifth tooth pulled by a Chinese Canadian when I was 15. All operations were done with only a bit of local anesthetic and with me fully awake, but I didn't feel any pain; the actual injection of the anesthetic was by far more painful than the actual tooth-pulling. The OP seems to imply that Western dentists use general anesthesia for pulling teeth, which is definitely not the case except in unlikely circumstances (i.e. phobic patients).

As for Chinese people having weird medical concerns, that's definitely true. Most Chinese still subscribe to long-disproven theories from traditional Chinese medicine, and often prefer traditional medicine over scientifically-proven drugs. However, I don't think this is any different from Western people believing in homeopathy, faith healing, EM hypersensitivity, "natural" products (as opposed to chemically synthesized ones), etc. To put it bluntly, the general public is simply stupid, a statement that holds true across all cultures and across all time. --121.29.117.97 (talk) 16:23, 25 August 2010 (UTC)

(In response to one of the above comments) My mom also tries not to stand in front of the microwave for fear of radiation, but unless you have a fair bit of scientific knowledge, it's not obvious why microwave radiation is not dangerous. Consider this explanation that I offered my mom: "That metal surrounding the microwave chamber acts as a Faraday cage, greatly attenuating the intensity of the microwaves. The mesh on the door has very small holes, which don't matter because microwaves have a wavelength on the order of centimeters while the holes are 1 mm in diameter. Furthermore, microwave radiation is not ionization radiation like UV, and the individual photons which comprise it are not energetic enough to cause significant genetic damage, so normal cells are therefore not more likely to become cancerous." I'd be very surprised if a significant proportion of any country's population can even understand that explanation, let alone think up of it. --121.29.117.97 (talk) 16:41, 25 August 2010 (UTC)

In fact, the radiation that the microwave produces is harmful. It's the most harmful microwave radiation because it is at the exact wavelength to heat water, which makes up a fairly substantial part of our bodies ;) The good thing is that it's well contained in the microwave, at least to the extent that it's made it very difficult to determine any negative effect. Another point is that microwaves are used for such short periods (and often without human proximity) that it's unlikely to have a substantially damaging effect. Regards, --—Cyclonenim | Chat  19:16, 25 August 2010 (UTC)

Chinese anaesthetics used during tooth removal is usually just a small amount inejcted via a needle, while Western anaesthetic commonly involves gassing the patient to put them out of consciousness, though I'm sure it's also used vice versa. There have been incidents in Chinese history when painful procedures were done without anaesthetic, but this was usually during the Japanese occupation. See Unit 731. ~AH1 19:06, 26 August 2010 (UTC)

Human Appearance and Incest

If generation after generation of a family line were to have one daughter and one son who would then have children together would the children eventually be genetic clones of their parents? TheFutureAwaits (talk) 09:18, 25 August 2010 (UTC)

No. Each child would inherit a mix of genetic material from both of its parents. To be a clone a child would need to inherit all of its genes from only one parent, which is not possible within the natural human sexual reproductive process. Gandalf61 (talk) 09:25, 25 August 2010 (UTC)

But there are only two sets of genes to mix from and given that each generation would come from siblings most of the genes would be the same with the similarity increasing each generation. So at some point the genotype of the children would be the exact same as their parents, no? TheFutureAwaits (talk) 09:36, 25 August 2010 (UTC)

Oh, I see. You mean that the genetic diversity of this "population" will decrease over time, and so eventually there will be a generation in which the two siblings happen to be genetically identical, and from that generation onwards all of their offspring will also be genetically identical. I suppose that might happen in theory, if you assume are absolutely no mutations. Gandalf61 (talk) 11:13, 25 August 2010 (UTC)

Another question: how long would they be able to do that before their descendants become unfertile/impotent/too deformed to survive until sexual maturity? The Spy Who Came in from the Cold (talk) 09:41, 25 August 2010 (UTC)

Very, very soon I think. In the second generation awful recessive genes will already come to the fore. Recessive genes are important for past battles Humanity successfully fought but where the environment doesn't show them anymore. When that battle comes back again, the few "freaks" will survive and the previous "dominant" gene might not survive in Humanity at all. Until then, we don't need that phenotype. So, if you had such major incest, any recessive genes would come out, and in fact after a few generations you simply would have awfully maladaptive ones, I think it would not be many before the chidlren had an IQ of a squash. (summer squash) 84.153.253.222 (talk) 09:54, 25 August 2010 (UTC)

(edit conflict)What I think the OP is asking is this

At first the father has for chromosome 1, the combination Pp and the mother has Mm. The girl has a 50/50% chance of inheriting the same chromosome as her brother, for MP, Mp, mP or mp. Each chromosome has a separate 50%/50% of being the same in both children.

If the children both have the same two copies chromosome 1, say Mp, and were to have their own children, then each grandchildren would separately inherit Mp (50%), MM (25%) or pp (25%).

(The statistics start getting interesting at this point)

Ignoring cross-over and de-novo mutations, once the two children are homogeneous for a chromosome then all their children will remain that way. Eventually the children will be homogeneous in all their chromosomes. Except for the sex-selection chromosome XX and XY, for which the girl will end up being homogeneous for both her X chromosomes, either from the ancestral father or mother. The boy will have the same X chromosome.

How long does it take for the descendants to become homogeneous in all their chromosomes?

My apologies if I'm not correct in my re-phrasing of the original question. CS Miller (talk) 10:08, 25 August 2010 (UTC)

Yes that's exactly it, thanks for restating it so clearly. I have a feeling they would have homogeneous chromosomes very quickly considering how little difference there is in the DNA between siblings. And once homogeneous then if they had two sons they would both be twins even if they were born years apart. TheFutureAwaits (talk) 11:57, 25 August 2010 (UTC)

The Misplaced Pages article Incest is about social/legal/religious consequences. The article Inbreeding is informative about biological consequences in humans. Cuddlyable3 (talk) 11:03, 25 August 2010 (UTC)

There are many inbred strains of mice and other animals, so it is not impossible for humans to survive repeated inbreeding, particularly if the number of children with each generation is large. However, inbred mice seem to lack the vitality, fecundity, and intelligence of wild mice. Also consider that as with Tasmanian devils, inbred humans would suffer such odd plagues as contagious cancer. Wnt (talk) 15:18, 25 August 2010 (UTC)

The deal is this - because you get one of each chromosome (except the X & Y 'sex' chromosomes) from each parent (and each parent had a random chance of which of two they had would be passed on), there are 4 ways of mixing them. So for any two completely unrelated parents, there are 17.6 trillion genetically different boys and 17.6 trillion genetically different girls that they could have as children. However, when a boy and girl sibling mate, then for each chromosome, there are only a few possibilities:

• That the chromosome pair contains one from the grandfather and one from the grandmother (4 possibilities).
• That the chromosome pair contains two identical copies from the grandfather (2 possibilities).
• That the chromosome pair contains two identical copies from the grandmother (2 possibilities).

In the first case, the child would be OK - but either of the other two cases, the child is at great risk.

Normally, we have two different versions of each chromosome - so if one of them is faulty, and cannot produce some critical enzyme or something - then the other will make up for it. But if they are identical (which is a 1/6 chance in that third generation) - then any small flaw is going to manifest itself and you're in big trouble. With 22 (non-sex) chromosomes - the odds are good that several of them will turn out to be like that.

When you push your luck into yet another generation, you might get lucky and fix the problem by the child inheriting one of the duplicated ones and a diffent one from the other parent...but the odds are getting much thinner if there is already a 1/6 chance of the other person having the exact same problem. Once one any one of the four original copies of that chromosome fails to make it into the next generation (the odds of which are pretty high) then it's gone forever and now there are only three versions left...then only two..and finally, only one.

...and that's where things get really nasty. Once both boy and girl child have the same duplicated chromosome pair from the same ancestor - then there is no way (other than mutation) for that to ever get fixed in subsequent generations.

Keep that up long enough and (assuming they don't become sterile or die before having the requisite one boy and one girl) then more and more of the chromosome pairs will be duplicated like that. Only the Y chromosome will be unaffected by the problem since there is only ever one of them in males and any serious defect would have prevented the original male parent from functioning.

Eventually (although it might take a large number of generations to happen by chance) all 22 chromosomes would indeed become duplicated pairs - and the only genetic variation in subsequent generations would be between the boys and the girls.

However, the odds of that happening without the inbreeding killing off the blood line is almost zero. It couldn't happen in reality.

SteveBaker (talk) 15:31, 25 August 2010 (UTC)

Please see e.g. - mice can undergo 55 generations of brother-sister mating (the OUW strain) without any particularly noticeable effects, though sometimes mutants shake out much sooner. I wouldn't doubt that however unremarkable they seem to us, these inbred creatures are C'thulhean horrors from the perspective of a wild mouse, but they are certainly viable. Wnt (talk) 15:45, 25 August 2010 (UTC)

See Charles II of Spain --Dr Dima (talk) 16:21, 25 August 2010 (UTC)

The Golden hamster is a perfect inbreed and there are no obvious problems with it. --Stone (talk) 17:25, 25 August 2010 (UTC)

But it only has a lifespan of 2-3 years max. Not a lot of time to develop cancers. Googlemeister (talk) 18:32, 25 August 2010 (UTC)

This chapter seems to be messed up with additional questions and answers about possible damages. Therefore I would like to summarize and add a little bit:

The question is, if in a row of inbreeding sibling pairs the genome at last will become identical. The answer is, it approximates identity. On average 50% of the genes of two siblings will come from the same source. Also part of the remaining 50% will be identical, too, because the sources are already identical. That means that the portion which is different is around 1/2^(n+1) with n = number of inbreeding generations. With ca 23000 genes you will have less than one gene difference after approximately 14 generations. This of course is a very rough approximation because of multiplication of uncertainty, connectedness of genes, fragility of genes and mutations. Please note for example that you have less than one chromosome difference after approximately 4 generations. Without crossings you would have roughly 15% chance of identity after only 2 generations. There is also the aspect that part of the genome is always maternal and with normal sex there has to be the difference between X and Y. -- Tomdo08 (talk) 16:09, 29 August 2010 (UTC)

do more socially adept people mind less being lied to?

So, this is just my personal experience but I was kind of a recluse and not well-integrated socially, but then later improved substantially. For me personally, it seems I don't really mind being lied to. In fact, I don't consider it any worse than a web server sending other than perfectly formed standards-compliant HTML: in the end, the server sends your browser something because it wants the browser to behave a certain way (and its author knows it will behave that way) and the end result, the experience in browsing that page, is what matters. So with lies, I don't care if it doesn't conform to the truth, I care more about what the end result is of my being lied to. Often it can be obviously beneficial to me, and I don't care. This extends to companies too: a company one of whose products I own was sued for deceptive advertising, as their advertizing made it seem as though their products were hand-made (the ads showed an artizan making them), even though they were anything but: they were mass-produced in factories. I just didn't care. I'm sure a few years ago, I really would have, as you can't show an ad and have ad text all talking about hand-making something, when that's not even how you make it... And now, I think it just adds to my enjoyment of my product.

So, my uestion is whether my "arc" is a usual one: do people, as they become better and better integrated socially and have more and more friends, just mind less and less being lied to? 84.153.253.222 (talk) 09:51, 25 August 2010 (UTC)

I have not found a study of such a subjective issue as minding being lied to. You seem to have developed a tolerance for it, but see Lie#Consequences of lying. Protection against misleading advertising is regarded as important to protect consumers and ensure fair competition, as evidenced by the many national organisations for regulating advertising. Cuddlyable3 (talk) 10:56, 25 August 2010 (UTC)

What you seem to be discussing is a form of instrumental rationality, but you seem to be asking for a value judgment on the issue. That varies across different perspectives. Economic theory has tended to idealize instrumental rationality as the primary motivator in human activities; social theory and psychology have tended to decry instrumental rationality as a relatively low level of cognition and social interaction. The problem boils down to a question of social 'good' vs. personal 'good': e.g. it's one thing if your football coach lies and tells you that you are the greatest team he's ever seen (because that lie can build social cohesion and produce better performance overall), but it's another thing if I lie to your wife/girlfriend that you've been cheating so that I can sleep with her (because that lie could destroy your relationship for my benefit). It's not a simple issue. as a rule of thumb, the more that a lie is seen as a collective social fiction (the way that Santa Claus is broadly treated as real in certain contexts through Western culture) the less objectionable it is; the more a lie is seen as creating an advantage for some at the expense of others, the more objectionable it is. --Ludwigs2 15:29, 25 August 2010 (UTC)

Conscientiousness may be what you are describing - people high in that trait prefer working to having parties, and dislike lying. 92.15.17.245 (talk) 21:02, 25 August 2010 (UTC)

Skin effect and AC resistance

I wounder why it is called AC resistance rather than Skin inductance for instance. I assume, it can't be added algebraically (without vectors or phasors! can it?), to the DC resistance, although I don't know how to get its precise derivation. I'd be obligated to know how to consider both DC and AC resistances at some low and intermediate frequencies. --Email4mobile (talk) 12:26, 25 August 2010 (UTC)

I assume it's called "AC resistance" because it's simply resistance measured using an alternating current.

While we're at it... I wonder whether a bundle of carbon nanotubes used as a power line would be immune to the skin effect, like the ultimate litz wire? Wnt (talk) 14:17, 25 August 2010 (UTC)

biology(human heart rate)

why woman have higer heart rate about 72 to 80 bpm compare with man which is only 64 to 72bpm only? —Preceding unsigned comment added by Syafy (talk • contribs) 13:47, 25 August 2010 (UTC)

I'm not sure it does vary, nor is elevated heart rate (>90 bpm) safe for either sex. See PMID 7963118, PMID 20719745. Bear in mind that exposure even to low levels of nitrogen or sulfur dioxide pollutants leads to measurable alterations of resting heart rate, though this study also finds a measurable sex difference. I do not mean to suggest that the sexes are precisely alike - there are too many papers for me to read that find otherwise on one technical point or another - but I suspect it's more productive to look for other environmental and lifestyle factors. Wnt (talk) 14:41, 25 August 2010 (UTC)

Size. In general smaller hearts beat faster, and women are usually smaller than men. Ariel. (talk) 21:54, 25 August 2010 (UTC)

As for the dangers of an abnormally high resting heart rate, see tachycardia. ~AH1 18:59, 26 August 2010 (UTC)

What kind of bug is this?

I've been searching for quite some time an I am unable to identify this bug. If anyone can help I would appreciate it.

photo 1 photo 2 photo 3

Keegstr (talk) 14:28, 25 August 2010 (UTC)

Please, please PLEASE - when you are asking for identification of animals and plants (and especially insects) it helps us immensely if you tell us where in the world you saw this creature. There are about 2 million species of insects and every scrap of information helps! SteveBaker (talk) 14:41, 25 August 2010 (UTC)

Sorry! It was seen in Chesapeake, Virginia (USA) at the Chesapeake Arboretum. It was on a plant in their herb garden, but I did not get the name of it. Keegstr (talk) 14:48, 25 August 2010 (UTC)

I would think it was some sort of aphid by look, but it seems a bit larger (aphids rarely get over a centimeter in length). --Ludwigs2 15:10, 25 August 2010 (UTC)

Looks like a true bug, suborder Heteroptera, to me. --Dr Dima (talk) 16:35, 25 August 2010 (UTC)

That is a definitely a hemiptera nymph of some sort. Almost certainly heteroptera. Note the lack of wings, which only show up in later (the final?) instars. If you'd like a more precise ID, post it to bugguide.net; the people there are very helpful and knowledgeable. Or you could try browsing through the taxa there and see if you can spy it. -Craig Pemberton

Redshifted starlight

Now we know the universe is expanding because distant stars are moving away from us correct? And we know they are moving away from us because their light is redshifted. So is it fair to say that pretty much all the stars we observe from Earth have their light redshifted? 148.168.127.10 (talk) 15:11, 25 August 2010 (UTC)

See Blue shift. -- ToE 15:15, 25 August 2010 (UTC)

Not all stars (and in particular, galaxies) have a positive redshift. But, as Hubble pointed out in 1929, and has been repeatedly re-confirmed with more recent equipment, the overwhelming majority are moving away from us. Nimur (talk) 15:35, 25 August 2010 (UTC)

But if space is expanding at a rate fast that light, how can any stars be moving towards us? 148.168.127.10 (talk) 15:58, 25 August 2010 (UTC)

The expansion of space depends on distance from the observer; it is not faster than the speed of light for most of the observable universe. And, nearby objects may have proper motion in any direction, independent of the expansion of space. The important thing to realize is that the expansion of space is most relevant at very great distances. For nearby objects (like Earth's Moon or Proxima Centauri), the rate of expansion is so small as to be negligible for most purposes. In these cases, the (Newtonian) gravitational and inertial motions of the object are sufficient to explain their apparent velocity toward or away from us. Nimur (talk) 16:09, 25 August 2010 (UTC)

Stars that have a negative radial velocity are approaching the Sun. Sirius, for example is expected to arrive closer than it is now in a few thousand years. ~AH1 18:58, 26 August 2010 (UTC)

The rate of expansion within the Milky Way, and for that matter the Local Supercluster, is zero. Hubble's Law only applies to relative velocities of superclusters. -- BenRG (talk) 23:49, 26 August 2010 (UTC)

Now I'm confused. Do you mean the local supercluster is not expanding at all, or expanding so slowly as to be negligible? Nimur (talk) 15:37, 27 August 2010 (UTC)

I think I meant the local group rather than the local supercluster. I'm a little unclear on whether superclusters are gravitationally bound. In any case, gravitationally bound systems don't expand with the Hubble flow. Earth doesn't expand, the solar system doesn't expand, the galaxy doesn't expand, etc. (Although gravitationally bound systems can oscillate between a minimum and a maximum size, in which case they are expanding half of the time.) -- BenRG (talk) 04:24, 28 August 2010 (UTC)

All of the stars visible to the naked eye belong to the Milky Way galaxy, which is not expanding, so they're as likely to be blueshifted as redshifted. Even the few naked-eye visible galaxies belong to the Local Group, which is also not expanding. -- BenRG (talk) 23:49, 26 August 2010 (UTC)

Stars that have passed near the Sun

I was just reading Barnard's Star for some reason, and was astounded to read that in merely 10,000 years, the star is expected to come from 6 light-years to 3.8 light-years in distance - but will still not be the closest star because Proxima Centauri will have come even closer. I hadn't really understood that stellar proper motions were so large.

Has anyone traced the current motions backward and constructed a table/diagram/video of all the stars passing by the Sun in the past few hundred thousand years? (it would be nice to cover all the recent ice ages, but I don't know how precisely the motions are known...) Wnt (talk) 15:31, 25 August 2010 (UTC)

See List of nearest stars#Future and past. --Dr Dima (talk) 16:49, 25 August 2010 (UTC)

If the Nemesis star exists it's always closer than 3.8 light years and it can come a lot closer. I don't think it's the greatest problem for mankind however. Smartse (talk) 00:53, 26 August 2010 (UTC)

Gliese 710 is expected co come fairly close to the Sun in the future, while Algol had been pretty close at one point. ~AH1 18:56, 26 August 2010 (UTC)

how to tackle Deliquescence property

could you please tell me about some chemicals that will destroy deliquescence property of salts. or any other way to stop the salts from absorbing water from atmosphere EXCEPT using airtight containers...thanx--Myownid420 (talk) 16:33, 25 August 2010 (UTC)ei

You can't destroy the property, you could either store it with a different substance that absorbs water more strongly, silica gel would be the most obvious, but you can also use rice as it too absorbs water pretty effectively. Smartse (talk) 18:52, 25 August 2010 (UTC)

Put a stronger deliquescent in with the salt. --Chemicalinterest (talk) 22:50, 25 August 2010 (UTC)

You need to store the deliquescent salt in a sealed container with a desiccant. Silica gel is a common one, but a lot chemistry labs use calcium chloride in their desiccators. They even sell it doped with Cobalt(II) chloride to know when it is "spent". --Jayron32 04:02, 26 August 2010 (UTC)

Water on skin

If I put water on my skin, will it hydrate it? Is that a secret that skin cream multinationals don`t want us to know? --Quest09 (talk) 16:34, 25 August 2010 (UTC)

Yes, at least to some extent. Have you ever had wrinkled finger tips after swimming? This is due to the skin absorbing water. However, this is not to say that applying water will cure dry skin. Indeed, topical application of water could have a net drying effect in some circumstances. SemanticMantis (talk) —Preceding undated comment added 18:37, 25 August 2010 (UTC).

Wrinkle_(skin)#Pruney_fingers

When advertisements for cosmetics and other "beauty" products tell us that what they are trying to sell us will (re-)hydrate the skin, it often has nothing to do with water. (Or truth.) HiLo48 (talk) 21:00, 25 August 2010 (UTC)

Our moisturizer article, which needs to be way longer, states that the point of a moisturizer is to hydrate the skin while decreasing evaporation. Comet Tuttle (talk) 21:04, 25 August 2010 (UTC)

Despite the name, skin is 'hydrated' with oil, not water. You can not add water to skin since the hydrostatic equilibrium needs to be kept at a specific level. What you commonly experience as 'dry' skin, is actually a lack of oil, not water. Ariel. (talk) 21:58, 25 August 2010 (UTC)

The oil in human skin is sebum. Though that article claims that low levels of sebum do not cause low skin moisture, sebum probably is involved in decreasing evaporation. SemanticMantis (talk) —Preceding undated comment added 22:00, 25 August 2010 (UTC).

Besides oils, humectants also play a role, e.g. glycerine, urea, alpha hydroxy acids such as lactic acid or glycolic acid. Wnt (talk) 14:43, 26 August 2010 (UTC)

I searched "skin hydration", and the first five results were Dead Sea salt, hyaluronan, taurine, stratum corneum and moisturizer. ~AH1 18:54, 26 August 2010 (UTC)

Why does hair grow so long on the human head?

The article on Human hair growth doesn't seem to answer this question. Although, as humans, we're used to the idea that head hair can grow to extreme length compared with that elsewhere on the body, to another species this must surely seem to be as defining a feature for the human species as, say, a peacock's tail is for that species. It doesn't seem to serve any function, other than display. Is that correct? How and why did human hair growth patterns evolve in this way? Has work been done on this? Shouldn't it be referenced somewhere? Ghmyrtle (talk) 20:02, 25 August 2010 (UTC)

This might not be the correct answer, it's just what I've always assumed. The head is very vascular in nature so it transfers heat very quickly. In that sense it's similar to your extremities, except its supply is not cut off when we get hypothermic because our brain always needs oxygen to ensure our survival. The more hair you have on your head, the more air that is present to insulate it, so having hair that grows on your head is pretty useful. What I don't understand is why our hands and feet aren't the same? I mean, in modern times it's possible to cope without hands with the help of modern society, but I doubt our ancestors millions of years ago had it quite as easy. Regards, --—Cyclonenim | Chat  20:10, 25 August 2010 (UTC)

I'm not sure either, but it might also be a consequence of sexual selection - it's for this reason that men have facial hair. — Yerpo 20:16, 25 August 2010 (UTC)

Have a look at a discussion on the same question a few weeks ago. Alansplodge (talk) 20:27, 25 August 2010 (UTC)

Oops, sorry, missed that one.... :( Ghmyrtle (talk) 21:29, 25 August 2010 (UTC)

I assumed it was the other way around - women usually have very little facial hair because of sexual selection. thx1138 (talk) 00:30, 26 August 2010 (UTC)

Well, yes, but long hair has been a sign of "femininity" for a veeery long time. It's the pattern of growth, not just overall length. Of course insulating the brain or some other physiological function might also have something to do with it. — Yerpo 07:51, 28 August 2010 (UTC)

Tree with leaves on bottom but not top

I am curious what could have caused this. Mathew5000 (talk) 20:26, 25 August 2010 (UTC)

Several possibilities: 1) with a lack of water, plants tend to first lose leaves at points furthest from the roots 2) a disease could have taken hold near the top and has started spreading downward from there 3) some insects pests prefer the tops or outermost leaves of trees/plants. It's too hard to tell without being able to look close whether any of these possibilities may be the right one. —Preceding unsigned comment added by 148.177.1.210 (talk) 21:06, 25 August 2010 (UTC)

148 has it. Is it a birch? If so, I'd go with lack of water, because birches tend to like moist conditions. Also could be due to physical damage, such as lightning strike. SemanticMantis (talk) —Preceding undated comment added 22:05, 25 August 2010 (UTC).

I have experienced this problem recently with a Dogwood. It was definitely due to lack of water associated with several years of significantly-below-average rainfall. Dolphin (t) 22:58, 25 August 2010 (UTC)

I have a tree in my neighbourhood that has its very highest branches missing leaves. Not sure what caused this or if it formerly had leaves there. ~AH1 18:46, 26 August 2010 (UTC)

If the plant has anything to say about it, during times of stress, plants try to lose their oldest leaves first, i.e. the less useful ones closer to the ground. John Riemann Soong (talk) 04:52, 27 August 2010 (UTC)

Breeding

Besides dogs, cats, rats, and fish, are there any other animals that have been subject to human breeding programs primarily intended for changes in appearance as opposed to, say, taste, growth rate, song, speed/agility or type and quality of hair/wool produced? Exploding Boy (talk) 22:46, 25 August 2010 (UTC)

We actually have a list: List of domesticated animals Wikiscient (talk) 22:55, 25 August 2010 (UTC)

Oh, didn't read the specific part of your question; not sure, but the list would be a good place to start. Wikiscient (talk) 22:59, 25 August 2010 (UTC)

Hmm, I guess I forgot to add hamsters and maybe rabbits to the above, but the list mostly deals with animals used for work, food, and clothing. Exploding Boy (talk) 23:01, 25 August 2010 (UTC)

(EC) Sorting the list by "purpose," the only item on the list with only "show" for a "purpose" is the Barbary Dove (Streptopelia risoria). Wikiscient (talk) 23:05, 25 August 2010 (UTC)

What got me thinking about it was reading the article Dodo. Since it has a close living relative, and since people have been known to attempt to resurrect extinct dog breeds, I began to wonder whether it would be possible to "recreate" the Dodo, and from there began wondering whether the type of breeding programs that have given us dogs as diverse as Chihuahuas and Irish Wolfhounds have been used on other animals for similar reasons. Exploding Boy (talk) 23:38, 25 August 2010 (UTC)

What would be the point? You wouldn't have a dodo- you would have a bird that looked like a dodo. Anything you would want to study about it (behavior, genetics, etc) would be completely different. 149.169.164.52 (talk) 23:57, 25 August 2010 (UTC)

I know that; that wasn't really the point of my question. Exploding Boy (talk) 23:58, 25 August 2010 (UTC)

All dogs are the same species, so resurrecting an extinct dog breed isn't quite the same thing as recreating a distinct species. Just consider the amount of evolutionary time you are trying to "undo" or recreate, however you want to put it. ALL dogs have a common ancestor 50,000 years ago, the majority of dog breeds today probably have common ancestors only a few hundred years ago. From a cursory look at the dodo article, it appears the dodo's most recent common ancestor is about 20 million years ago. That should put some perspective on it. Vespine (talk) 00:17, 26 August 2010 (UTC)

Again, I know that. It was more about recreating the appearance of the Dodo than the actual bird. Exploding Boy (talk) 00:26, 26 August 2010 (UTC)

Yeah sure, what I said equally apples to appearance. Recreating the appearance of a few hundred year old dog breed is going to be orders of magnitude easier then recreating the appearance of a 20 million year old distinct species. Vespine (talk) 00:33, 26 August 2010 (UTC)

Well, off the top of my head you can add mice and pigeons, although I'm sure there are other domesticated pet species which have been bred for appearance. Equisetum (talk | email | contributions) 00:04, 26 August 2010 (UTC)

Check out the domesticated silver fox. Also budgies are bred for color. Ariel. (talk) 00:06, 26 August 2010 (UTC)

Oh yes, I forgot about silver foxes. Of course, that was about taming rather than breeding specifically for appearance, wasn't it. Exploding Boy (talk) 00:26, 26 August 2010 (UTC)

Horses are bred for looks in addition to other qualities. thx1138 (talk) 00:32, 26 August 2010 (UTC)

Very hard to define 'primary' motivations for selection. In choosing fatter cattle, for example...is a fat sheep 'better'? Natural human tendencies for selecting the 'best-looking' breeding pairs comes into play, so there is a degree of change in appearance in any and all domestication, whether deliberate or otherwise. And over the long timescales, it is impossible to decide whether the many people making the selections were primarily motivated to select for appearance. I think you could find quite strong evidence of it in most pet species. Some that come to mind as, perhaps, more clear-cut primary choices over appearance (and have not been noted here) include Domestic Pigeon / Fancy pigeon, Guinea pig / Hamster / Gerbil / Chinchilla / Fancy rat, Pet skunk, Domestic Canary (and other caged birds, and certainly parrots and parakeets etc), Ducks, and I imagine lots more. Check Piebald too, because there are very very few piebald species in the wild.

With regards to the poor Dodo, a related short poem that I learned in New Zealand springs to mind — try to read it with a Kiwi accent, where 'moa' sounds the same as 'more', and it rhymes; No Moa, no more, in old Aotearoa, Can't get 'em they've et them, They're gone and there ain't no Moa.

For those interested in such topics, I highly recommend the book The Ancestor's Tale.  Chzz  ►  01:09, 26 August 2010 (UTC)

Responding to the question about breeding a bird to resemble the Dodo, that process is called "back-breeding". And there is a Misplaced Pages article on it, "breeding back". Also see Quagga Project. Mathew5000 (talk) 06:08, 26 August 2010 (UTC)

Budgerigars have definitely been bred for looks, all in the past 200 years. HiLo48 (talk) 06:28, 26 August 2010 (UTC)

Heck Cattle Googlemeister (talk) 14:41, 26 August 2010 (UTC)

Chickens are another example (there has been breeding for other purposes, too, but there's a long established tradition of ornamental chickens). Arguably, humans. Warofdreams talk 14:47, 26 August 2010 (UTC)

August 26

Hitler DNA

It's that time of the year again, when the papers are desperate to fill up space and will publish just about anything.

A week ago, Belgium's Knack.be published "news" of a "study" that "determined" that Adolf Hitler's DNA contained a haplogroup found more often in North African (Somali, Berber), Southern European (Greek, Sicilian), and Jewish populations than in the general European population. The story languished for a week, was picked up by the UK's tabloid Daily Mail, and then exploded across the Internet, all the while morphing to become even more sensationalistic and titillating. Supposedly respectable newsmagazine TIME, in a regular column titled "It's Science" authored by Megan Gibson, headlined its "report" New Research Shows That Hitler Had Jewish Roots.

Predictably, people have started streaming in trying to insert this "breaking news" into Misplaced Pages. Initially they came from the crazy/evil range of the spectrum, now they're mostly ignorant doofuses taking everything they read at face value. In this they are aided immeasurably by Misplaced Pages's idiot-friendly policy of "verifiability before truth".

So far, at Adolf Hitler, the lines of defense seem to be holding (see also the article's Talk page). At Alois Hitler, I am all alone. Help in reverting the insertion of this garbage would be appreciated. Also, at the Talk page for Haplogroup E1b1b someone asks about this. It would be nice if a population geneticist (well, I can dream) could provide a scientific answer there, so that one could then point people to it.--82.113.106.29 (talk) 02:58, 26 August 2010 (UTC)

Firstly, I think you're in the wrong place; the reference desk is for asking questions, not for getting editing help.

Next, I removed the personal comment about Gibson; I know it was a joke/quote, but still: personal attacks are not tolerated. I'd also prefer if you didn't refer to editors as "ignorent doofuses", and suchlike; I sympathise with you, I know that it can be frustrating, and know it is hard to stay calm, but please try.

I suggest you read WP:DISCUSS, and possibly try Misplaced Pages:Content noticeboard, perhaps request page protection, or whatever. Best of luck,  Chzz  ►  03:15, 26 August 2010 (UTC)

Why shouldn't Misplaced Pages cover the news? A single marker may not be proof, but it's undeniably some degree of scientific evidence, supporting a speculation that existed long before the PCR machine. If it gives people some mirth, so much the better. If people had been quicker to laugh at Hitler in former times, there might be more of these markers in Germany. Wnt (talk) 14:49, 26 August 2010 (UTC)

Misplaced Pages should take extreme care in covering the news. Particularly when 'the news' is reporting on scientific findings — the reader of the typical newspaper might be forgiven for believing that we've discovered the cure for cancer every year since 1980, or that porn stars are a worthwhile source for information about vaccination and developmental disorders. There's a nasty tendency for a neutral, watered-down, cautious hypothesis in the peer reviewed literature to become a slightly-firmer off-the-cuff casual quotation in an interview, which in turn becomes a blazing, absolute, out-of-context headline for tomorrow's paper. TenOfAllTrades(talk) 15:07, 26 August 2010 (UTC)

This is true, but I believe "extreme care" should consist of balancing one source against another. Mass delusions such as John F. Kennedy assassination conspiracy theories or Moon landing conspiracy theories are notable and worth reporting, even if completely unsupported by fact. Half-truths are also worth reporting, and best reported by including the necessary background for readers to see the whole truth. Wnt (talk) 16:21, 26 August 2010 (UTC)

The point I would like to make is that Hitlers body was never found, and the Russian cold war claims to have part of his skull are dubious at best. So they could not have done this test, as there is nowhere to get the DNA sample from. Hence in my opinion, the claim is nulkl and void and should not be included in the respective articles. —Preceding unsigned comment added by 195.89.16.154 (talk) 19:16, 26 August 2010 (UTC)

Argh! "Verifiability before truth" is your savior here. Arguing the "truth" of this is impossible - neither you, nor the other editors you're arguing have any clue what the truth is. "Truth" as a standard fails you miserably here. We don't know the truth. However, the "verifiability" standard is of immense help here.

The available 'reliable sources' don't say that Hitler was Jewish - they say that such-and-such scientist performed some test that produced some result that may be interpreted as suggesting that Hitler could have been Jewish. That is also "a fact". Someone did say that. However, until that scientific paper has been published in a reputable journal - you can't report that what the paper says is "true". When that paper emerges, we can read what it actually says (which, I'm pretty sure won't be "Hitler was Jewish" but rather "Hitler's DNA shows some genetic group or other") - and report on exactly that. Remember - WP:SOURCES says that:

• "Articles should be based on reliable, third-party (independent), published sources with a reputation for fact-checking and accuracy'" - that last phrase is important here - some junk TV news show or some sensationalist "It's Science" column don't do that - so they don't count.
• "Academic and peer-reviewed publications are usually the most reliable sources where available, such as in history, medicine, and science..." - so go to the source publication and get your information there - NOT in the TIME magazine article.
• "Where a news organization publishes an opinion piece, the writer should be attributed (e.g. "Jane Smith has suggested...")" - so you can say "Megan Gibson of TIME magazine says XYZ is true" - but don't say "XYZ is true" unless you have something with the solidity of a scientific paper published in a reputable journal.
• "Exceptional claims require exceptional sources..." such as: "Claims that...would significantly alter mainstream assumptions, especially in science, medicine, history, politics, and biographies of living persons."

All of these say that our articles cannot say "Hitler was Jewish" - only that "Megan Gibson says that Hitler was Jewish"...or whatever it is she actually says. Once you have established that fact, two other Misplaced Pages policies swing into play: Firstly that you can only publish her opinion if it's Notable...secondly that you may not give fringe theories undue weight. This is a very new finding - doubtless only one scientist has done the test - doubtless that scientist didn't come to the actual conclusion that the junk press came to. So perhaps mentioning the TIME article AT ALL is giving it undue weight. One last thing to note is that Misplaced Pages is not a newspaper. We can take our time over considering these things. We don't have to rush to add this to the article - we are supposed to sit back and let events play out and then report on the results when they are better settled and accepted. WP:NOT says:

• "Misplaced Pages considers the enduring notability of persons and events. While news coverage can be useful source material for encyclopedic topics, most newsworthy events do not qualify for inclusion.".

SteveBaker (talk) 20:49, 26 August 2010 (UTC)

I think you're quoting that out of context, but we shouldn't argue policy here. Though I think the news reports deserve to be reported in the article with or without detail, I think this entry here could be deleted now without loss, because we don't yet have anything to analyze. Wnt (talk) 21:59, 26 August 2010 (UTC)

Mirrors

Glass, if heated enough, can be forced to change shape. Is it possible to heat a mirror (it's plane) and press it someway to make it into a concave mirror without damaging it's ability to reflect ?  Jon Ascton  (talk) 06:27, 26 August 2010 (UTC)

Mirrors come in many different forms; mirrors with glass are usually silvered glass (a layer of silver deposited behind the glass); since silver and glass melt differently, melting and forming a curved mirror from a straight one may not result in the desired end. Instead, you would probably isntead use a normal, unsilvered piece of glass, shape that, and THEN apply the silver. --Jayron32 06:43, 26 August 2010 (UTC)

Thanks !! Are you sure ? But how does one turn glass into mirror ? Is it possible to achieve full mirror brilliance that is required in optical appliance? —Preceding unsigned comment added by Jon Ascton (talk • contribs) 07:30, 26 August 2010

You can buy sheets of mirrored plastic which are easy to bend, and might perhaps melt into shape also. Shaving mirrors are already concave. 92.15.13.237 (talk) 10:54, 26 August 2010 (UTC)

Optical quality mirrors are made by Sputter deposition of aluminium on a glass or metal base. Reflections from this surface are free of the loss and internal reflections that glass introduces. Cuddlyable3 (talk) 12:35, 26 August 2010 (UTC)

I watched a demo where they poured some kind of chemical (something based on silver nitrate I believe) into a flask and made it into mirror instantly. Ariel. (talk) 18:34, 26 August 2010 (UTC)

this and this telescope both use a liquid mirror, where the mirror is continuously spun to form a concave shape at a temperature above its melting point. ~AH1 18:40, 26 August 2010 (UTC)

The key here is that it's not the glass that's doing the reflecting. In fact, in most optical applications, you go to great lengths to eliminate any reflections from the glass. In the case of a mirror, it's the backing that does the reflecting. The glass merely serves as a suitably stiff medium to hold the mirrored surface still - and perhaps to protect it from damage. If you want a flexible substrate, use something like mylar film. I used to work on those big flight simulators that the airlines use to train their pilots. Some of those use gigantic toroidal-section mirrors and rather than make them out of glass, they make an accurately shaped frame to hold the mylar and apply a partial vacuum to pull it into the desired shape. The result is super lightweight and really nicely reflective (although perhaps not to the standards required by large telescopes, for example. Altering the amount of vacuum applied would alter the curvature and thereby allow you to dynamically adjust the focal length. SteveBaker (talk) 20:25, 26 August 2010 (UTC)

I think one more thing needs to be said, which is that the thin layer of reflecting metal would be relatively fragile compared to the thicker piece of glass. So if you took a mirror, heated it up, and started bending, what would most likely happen is that you'd damage the reflective coating so it wasn't a mirror any more. So the answer is that it's possible but not practical.

Also, starting with something like a mylar sheet mirror will only be practical if you want curvature in one direction -- that is, a distorting mirror that changes the shape of objects. To convert a flat surface to a spherical curve, like for a shaving mirror that enlarges the reflection, you'd have to redistribute the mass so the thickness would not be uniform. Not simple. --Anonymous, 22:32 UTC, August 27, 2010.

Kalam argument page needs science help

The section of the Kalam argument page dealing with it's scientific objections needs help to make sure it's free of bias. The scientific viewpoint there is severely under-represented. If anyone wants a small fun project and exercise in wiki diplomacy, this might be a good one to take a stab at.

One specific issue I see right now is that the arguments about causation are unfairly and misleadingly framed. A question of causation is falsely deflected into a question about energy. That is not what Stenger argues, or what the argument is about.

I'm currently away at college and classes just started so I won't be able to work on this, but it really does need some help. Best regards, -Craig Pemberton 06:29, 26 August 2010 (UTC)

I think the best thing to do with that article is to merge it with Teleological argument. Cuddlyable3 (talk) 12:18, 26 August 2010 (UTC)

The article on the Hartle–Hawking state could use elaboration; perhaps that would help.

I don't understand why a beginning for the universe is so crucial to the argument. It would seem that a universe with an infinity of past time offers an infinity of opportunities for organisms to arise; hence any given organism is not the largest, nor the wisest, nor the most powerful; hence a God must exist. At least to the standard of evidence, such as it is, otherwise being used here.

I am greatly skeptical of the idea that the Big Bang represents a beginning of time - to me, it seems like a mathematical singularity, infinitely hot, infinitely dense, infinitely fast-moving particles making an infinite number of interactions. To me it seems fairer to assume that time in the subjective sense is logarithmic relative to in the physical sense. In other words, once the universe was smaller than a cesium atom or a wavelength of light; but that only means that those physical laws and objects were irrelevant at that time, not that "nothing happened" and time hadn't started. The focus of physicists on "eras" of the universe in the first fractions of a second indicates just how much subjective time those tiny fractions actually comprised... Wnt (talk) 16:53, 26 August 2010 (UTC)

The big bang as such an infinitely dense singularity follows from general relativity in the absence of QM, but with QM we just don't know. With QM it could have started from literally nothing. "The Penrose-Hawking singularity theorems require the existence of a singularity at the beginning of cosmic time. However, these theorems assume that general relativity is correct, but general relativity must break down before the Universe reaches the Planck temperature, and a correct treatment of quantum gravity may avoid the singularity."-Craig Pemberton 23:58, 26 August 2010 (UTC)

Hmmm - in the last paragraph of "Objections and criticism", Craig needs to read the definition of the word "spontaneous": Self generated; happening without any apparent external cause.

The thing about articles like this is that we aren't here to prove or disprove the argument. We're primarily here to document what people have and have not said about it - what experiments have been done to prove or disprove it, etc.

Stenger's argument about quantum theory does indeed blow away the first premise on which this tottering edifice is founded...but even without that, saying that everything has to have a cause - and that we're going to arbitarily label this cause as "God" is a bit fraught. And going from that to the idea that this "cause" must be "personal, uncaused, beginningless, changeless, immaterial, timeless, spaceless, enormously powerful, and enormously intelligent being" simple doesn't follow from the argument. Indeed the argument of "First cause" says that for a god to exist, there has to be a cause for god. If god can be "causeless" then why not cut out the extra step and simply declare that the universe is "causeless"? And how the heck you decide that "enormously intelligent" derives from that is nuts! This "first cause" might be a simple, mindless physical process...a massively improbable quantum event of some kind perhaps.

But we are not here (in article space) to challenge what people have said. We need to report that he said these things - point out what other people have said - and put the argument into a suitable context in order that we don't give it undue weight or imply that it is in any way "true". The most I'd change in this article is to say somewhere in the introduction that this is not the view of mainstream science.

SteveBaker (talk) 20:19, 26 August 2010 (UTC)

Constellations

Hello. I'm am just starting to get in to amateur astrophotography, and I don't yet know much about constellations and stars. Could someone go here and here and make sure all the notes on stars are right and any more if possible? Thanks, --The High Fin Sperm Whale 06:38, 26 August 2010 (UTC)

A great piece of software I use which you may or may not be familiar with, but would definitely assist you is called Stellarium (computer program).Vespine (talk) 06:47, 26 August 2010 (UTC)

I once pointed a camera at Orion for 15 seconds using a camera through a window without any kind of tracking device or piggyback mount whatsoever. The result is here (top-left "star" is Mars). ~AH1 18:37, 26 August 2010 (UTC)

I think you're camera must have been bumped during exposure. The first of my pictures used a 15-second exposure and the second used 5-second, and the trails aren't nearly as long a yours. Also, you can see in yours that the stars look a bit like tadpoles, with a bright head and dim trails, indicating it was bumped. Can anyone help with my original questions? --The High Fin Sperm Whale 18:51, 26 August 2010 (UTC)

It could also be the camera's image stabilization feature. Those need to be turned off before taking astronomy pictures or gyro drift will cause the camera to adjust the mirror position to "correct" for camera movements that aren't actually happening. (The exception to this rule is cameras or telescopes specifically made for long exposures. They've got better gyros.) APL (talk) 19:21, 26 August 2010 (UTC)

Well, thanks for the tip Astro. And thanks Vespine, for introducing me to Stellarium. --The High Fin Sperm Whale 19:36, 28 August 2010 (UTC)

Astrology

I have heard that some Universities in India teach astrology as a science subject. Is that true ?  Jon Ascton  (talk) 07:33, 26 August 2010 (UTC)

A quick Google search tells me that it is true Zzubnik (talk) 10:15, 26 August 2010 (UTC)

Yes, and the Government of India/University grants commision has had a official policy guidelines on vedic astrology departments since 2001 this page has a list of Indian and foreign universities where vedic astrology is taught. Diwakark86 (talk) 11:19, 26 August 2010 (UTC)

Minimum-Diameter Nuclear Weapon Physics-Package

Hi.

   I want to know what is the minimum possible diameter of the physics-package of a nuclear weapon; i.e. not the diameter of the narrowest physics-package ever designed, but rather what is the smallest diameter that is scientifically possible for a physics-package?

Please note that this is a question of scientific/technical curiousity - not a homework question.

  Addendum: A nuclear physics-package compliant with the following parameters is sought.

1. Diameter of between 40mm (about 1.575") and 80mm (about 3.145")
2. Length not exceeding 320mm (about 12.6")
3. Any yield above one ton is acceptable.
4. Normal to high shelf life is required, as this device is intended for interplanetary (not interstellar) propulsion.

   Thank you in advance to all respondents. Rocketshiporion

It's worth looking at yields of actually designed weapons, as they do probably give some indication as to the trade-off between diameter and yield:

model	diameter	length	max yield
W48	6.1"	33.3"	.072 kt
W33	8"	37"	40 kt
W54	10.75"	15.7"	1kt
W9	11"	55"	15 kt
W19	11"	55"	15-20 kt

Now the high yield of of W33 might be exaggerated -- that's probably its theoretical yield with full boosting, and its non-boosted yield is probably around 10kt. But I suppose there's no reason to ignore boosting, a priori. But I'm a little dubious of 40 kt.

Six inches is pretty dang small for a nuclear weapon. This is not just because of the fissile material, but because of reflectors, shielding, etc. The itty-bitty W48 is actually an implosion weapon — probably a tiny core of Pu with a very clever linear implosion explosives package. The W33 is apparently a gun-type weapon. The 8" and 11" diameters are obviously constrained to the width of the artillery they are meant to be fired out of.

Could you go smaller than 6? What's the acceptable yield before you start calling it a fizzle weapon? (The W48 technically does have fission yield, but it looks like almost none of its plutonium fissions.) --Mr.98 (talk) 13:03, 26 August 2010 (UTC)

Incidentally, if you posted this at Talk:Nuclear weapon design, you'd probably get better answers from people who love to run back of the envelope bomb calculations. --Mr.98 (talk) 13:08, 26 August 2010 (UTC)

I see that oil well includes a cute video of a 10-inch casing. I wonder if this means that someone really could have plugged the BP well with a nuke, if equipped with an unusually healthy dose of mental instability. ;) Wnt (talk) 16:44, 26 August 2010 (UTC)

If your application can tolerate the lower shelf life (and the hugely greater cost), there are several isotopes with a lower bare sphere critical mass than Plutonium; some of these may be suitable for a nuclear explosive. The Nuclear Weapons FAQ discusses the possibility of a Californium primary, and says "a nuclear device smaller than 2 kilograms or so using Cf-251 is almost certainly impossible." If you combine that with the technology used to design the prolate Komodo primary for the W88 (which, like your question, stresses lower diameter in one dimension as a major design criterion) that stands to be tiny indeed. Part of George Dyson's book on Project Orion (nuclear propulsion) talks about Freeman Dyson and Ted Taylor considering how to make nuclear devices as small as possible; if memory serves Dyson refuses to say how small they thought they could go, and Taylor's subsequent advocacy partially surrounds the dangers of very small nukes. -- Finlay McWalter ☻ Talk 18:03, 26 August 2010 (UTC)

Also take a look at suitcase nuke. ~AH1 18:32, 26 August 2010 (UTC)

Perhaps I'm missing something, I know very little about nuclear weapon design, but the OP didn't ask for a small nuke. They asked for the smallest possible diameter. My assumption (which could be incorrect) was they don't care about the length. In the real world, it's unlikely anyone would design a ultra thin but long nuke (although the OP said they don't care if anyone is ever likely to design it) And there are clearly limitations which prevent an extremely smaller diameter nuke, no matter how long, in particular, how well you can compress the cylindrical mass. I wonder if this is a difficult question to answer, because no one is likely to be interested in designing something like that so there are potentially lots of unknowns. But it seems to me concentrating on mass or size is partially missing the point, at least as I understood the OP's question. Nil Einne (talk) 18:56, 26 August 2010 (UTC)

I suppose it somewhat depends on how you're going to deliver it. Could you not have a very long, thin mass of plutonium (or whatever) and fire it at a target at high enough speed that it would deform into a more spherical shape on impact and thereby go critical? It's hard to know. SteveBaker (talk) 20:00, 26 August 2010 (UTC)

That's kind of what I was thinking. Especially if you were happy with a very inefficient yield. I could imagine having a reeeeeeeally long gun-type that was verrry thin and used clever engineering to accelerate the Pu or HEU to fantastic speeds before colliding it either together or just smashing it into something undeformable so it all compressed. It seems like it would be very hard not to get some fission yield that way, e.g. 10-100 ton yield. --Mr.98 (talk) 23:53, 26 August 2010 (UTC)

Clever indeed! It would seem that in a case like that, forgetting to "carry the one" or something could turn your gun into a dirty bomb sitting right in your lap (figuratively speaking). Matt Deres (talk) 13:17, 27 August 2010 (UTC)

Please do not attempt nuclear explosion-based propulsion. Project Orion concluded that explosions would be a sub-optimal means of nuclear propulsion, and proposing them will make a lot of astronomers unhappy for the same reasons they don't like light pollution here on Earth. Please see that latter article and these ten speculative atomic rocket concepts from NASA from its external links. Why Other (talk) 02:25, 27 August 2010 (UTC)

Non-magnetic plasma?

I'm wondering if there is some substance that's like plasma but it is non-magnetic and doesn't react to magnetism? I don't mean fire/flame as that's a chain-reaction. I mean just basically an energy/matter kind of substance like plasma, but it's non-magnetic and doesn't react to magnetism (well reacts as much as say a vegeatable). Looking through things like List of states of matter has mostly theoretical options that I can't tell if they're magnetic or not and I can't tell if Quark-gluon plasma is magnetic. Are you ready for IPv6? (talk) 09:08, 26 August 2010 (UTC)

I think that to be non-magnetic, the "plasma" would have to consist of electrically neutral particles, in which case it is simply a gas, surely ? Gandalf61 (talk) 10:07, 26 August 2010 (UTC)

But very high energy like plasma though? Are you ready for IPv6? (talk) 11:32, 26 August 2010 (UTC)

Then that would be a hot gas. I think you may be confused about the nature and characteristics of plasma and the difference between a plasma and a gas. I suggest you read our article on plasma (physics), and then look at some of the examples of natural and artificial plasmas. Gandalf61 (talk) 11:55, 26 August 2010 (UTC)

Some kind of High-temperature superconductor? ~AH1 18:31, 26 August 2010 (UTC)

The Growth of Knowledge

How do we learn things that we don't know that we want to know?--Alphador (talk) 09:11, 26 August 2010 (UTC)

Your question is a bit too broad to get useful answers.if 'we' refers to humanity in general you might want to look at the article on the Scientific method. If you want to know how induviduals learn, look at Learning and Education - Diwakark86 (talk) 10:38, 26 August 2010 (UTC)

Sometimes we don't know that we didn't want to know something until we do know it, and then it's too late. An example is what getting old feels like. Cuddlyable3 (talk) 11:53, 26 August 2010 (UTC)

I read the question as, 'How do we learn things that we don't know but we want to know' since that made more sense with the section title as 'The Growth of Knowledge'. If the OP wants to know about how unexpected discoveries are made, then there are no answers. Since the discoveries are unexpected there are no fixed methods to follow. you may want to read about Serendipity - Diwakark86 (talk) 12:57, 26 August 2010 (UTC)

Answer: painfully.

Prof. Gian-Carlo Rota used to say,

"Learning is never fun.

Having learned is fun!"  ;) Wikiscient (talk) 18:06, 26 August 2010 (UTC)

See learning curve and knowledge. These days, there is the Information age and people can learn from the media (not always accurate) or from the Internet (also not always accurate). ~AH1 18:29, 26 August 2010 (UTC)

As a species - we mostly use some variation of the Scientific Method - we wonder whether something might be true (we "form a hypothesis"), then we try to think of a way to test whether that is true or not, then we try that test ("perform an experiment") and that tells us whether our idea was true (which makes it be a "Law" or a "Theory") or false (in which case we discard it and try to come up with another idea. If I turn the key and my car won't start, I form a hypothesis ("Maybe the battery is dead") then an experiment ("If I listen when I turn the key and hear the starter motor turning - then it can't be the battery") - so I turn the key and I hear the engine turning over - so that hypothesis is incorrect. Now I think "Maybe I'm out of gas" - and come up with another experiment ("look at the gas gauge")...and so on until I find an experiment that comes out right - and now I have gained the knowledge of why my car won't start. Of course we don't think that formally about it most of the time - but that's what we're really doing.

19:55, 26 August 2010 (UTC)

In general, it's often accidental; I remember reading somewhere a hypothesis that ceramics were discovered after someone accidentally put a clay vessel into a fire. Nyttend (talk) 21:13, 26 August 2010 (UTC)

Short of an E for Effort time viewer, I don't see a way to tell, but it just doesn't seem likely. Remember being a kid? How many more things are fascinating than a fire, and how many things can you do with a fire that are more fascinating than finding things to put in it and see what happens...? Wnt (talk) 22:06, 26 August 2010 (UTC)

To follow up on that, I should add that I think a lot of good science is done that way:

1. Identify something new you can do with the tools available to you
2. Try it and watch what happens ("experiment")
3. Look at what happened more closely and see if you can spot any unexpected or useful effects (devise a "hypothesis" that the experiment caused them)
4. Do the experiment differently and see if you can change what happens ("hypothesis" tested)
5. Try this repeatedly and make sure you can count on it ("conclusion")

Now this is different from the scientific method as often written, because the "scientific method" is a religion. Nobody tests it. Nobody proves that knowing it makes you a better researcher. The principal purpose of this religion (like many of a low order) is so that you can feel good about yourself and your technological society and look down on the primitives; you have faith that Dioscorides or Susruta or Ge Hong didn't know this crucial faith, so even if they invented mainstay medicines that have been used until the present day, it was just by accident.

So I won't say my version is "better" than others, but I will say that the idea of putting the hypothesis first and the experiment later is often a lie. Lots of researchers will do this out of conventionality, describing their work altogether out of its actual temporal and causal order, in a way to assuage peer reviewers as being a grand plan, when in reality one of their kids spotted a jawbone poking out of a cliff, or they saw a new gene chip in a catalog, and things went from there. Wnt (talk) 22:40, 26 August 2010 (UTC)

Not really. You can do observations of experiments - but they don't tell you anything until you form a hypothesis to explain why that happens - and devise a way to test that hypothesis. For example - I might give you the series of numbers 1,2,3,4,5,6 - you might "observe" that these are consecutive numbers and form the hypothesis that I am counting something. However, you need to do an experiment to test that hypothesis...like waiting to see if the next number is 7. When you discover that the next number is actually 10 - you must abandon that hypothesis and come up with another one...perhaps that I'm listing the factors of the number 60. So that the next number should be 12...when the next number I give you actually is 12, you have some evidence that your new hypothesis is the right one.

There isn't any particular reason - much less "proof" - that the scientific method is the best way to gather knowledge. But it is far and away the most successful way that we have to explain the world. All previous methods left humanity in more or less the same condition. It's only with the establishment of scientific method that technology has really taken off. All the wonders of the modern world would have been impossible without the scientific method.

The method is widely considered to be "the right way to do things" because it works really, REALLY well. Consider that computer you're sitting in front of - it only works because we understand quantum theory and can therefore build flash-memory chips using quantum tunnelling. No amount of just observing nature would have gotten us that. It too directed study - efforts to prove or disprove a hypothesis. But the scientific method certainly isn't the only way - and perhaps we'll one day find a better way.

Simply observing - without taking the hypothesis/experiment approach leads people to all sorts of wrong conclusions. Consider 'dowsing' - walking around holding a 'Y'-shaped stick and hoping to find underground water (or whatever). Someone walked around with a stick - 'observed' that they found water and jumped to the conclusion that they had discovered some major new phenomenon. They didn't take the next step - devise an experiment to determine whether the stick had anything to do with finding the water...hence, bad conclusion. SteveBaker (talk) 23:32, 27 August 2010 (UTC)

To answer the OP, there's various ways, depending on how you define "knowledge" and "learning", one could approach the question.

There's the purely practical, that is how do we go about teaching things to people: that's covered by the subject of pedagogy.

There's the purely metaphysical, that is how do humans in general know things, how do they know they know things, etc. That's the subject of epistemology.

Then there are people who have combined the two. The educator/philosopher John Dewey has some excellent works which combine the practical and metaphysical (a branch of philosophy called "Pragmatism") and deal directly with combining pedagogy (that is how to teach) with epistemology (that is, how we know stuff). I recommend Democracy and Education and How We Think as some great Dewey works to read. His earlier works, like Democracy and Education, were more practical in nature; he gets more esoteric in his later life, like Knowing and the Known. I still pull out Dewey once in a while. He's very readible; indeed some of his works should be mandatory for anyone considering becoming a teacher. --Jayron32 02:37, 27 August 2010 (UTC)

My reading of the question "How do we learn things that we don't know that we want to know?" is that the part "things that we don't know that we want to know" is referring to things that we may be completely unaware of or wouldn't necessarily recognise as having value in terms of increasing knowledge even if we were looking right at them e.g. going from 'flowers are colorful' to 'bees can see colors' took centuries. I thought the question touched on the 'things that you don't know that you don't know' issue like a knowledge landscape where constraints in your exploration methods can result in you not seeing a hill or even missing an entire continent. I think Diwakark86's answer partially addressed this interpretation i.e. randomness helps. Sean.hoyland - talk 06:35, 27 August 2010 (UTC)

When is the Age of Aquarius?

How many years from today will we begin to enter the Age of Aquarius? If we see the Aquarius constellation in the nightsky, does it mean we're in the Age of Aquarius? 99.245.73.51 (talk) 11:46, 26 August 2010 (UTC)

See Age of Aquarius. The beginning is debatable. We may be in it now, getting close to it, or still 400 years away. -- kainaw™ 13:52, 26 August 2010 (UTC)

Obviously it must have began when God arrived on Earth; unfortunately, the Government killed him, and his successors fled to Anatolia, triggering the apocalypse. But that was a long time ago - we'll all be okay and probably won't have a god come back to trigger another apocalypse until the next Age, when god returns in the form of a sea goat. In actual fact, there is no clear definition of this sort of "age" in a scientific context. The astrological and mythological parts are loosely based on precession of Earth's orbit - a fairly good overview can be found at the Astrological age article. All zodiacal constellations can be seen over the course of a 12-month cycle; so it's not sufficient to just "see" the constellation - astrologers claim (without explanation) that an age starts when a constellation lines up with something. Astronomers precisely measure the positions of each star and constellation, (using the equatorial coordinate system); astrologers then ignore these measurements and make nonsense up about alignments. Nimur (talk) 16:11, 26 August 2010 (UTC)

Due to precession and other related phenomena, astrological ages are actually offset. ~AH1 18:25, 26 August 2010 (UTC)

T-Rex

Is there any method by which a human could kill a T-Rex with their bare hands? TheFutureAwaits (talk) 12:22, 26 August 2010 (UTC)

Since you didn't specify an adult T-rex... It appears we don't really know the size of a T-rex egg but from what I'm reading there's a fair chance it was small enough that someone could carry one. If you carry the egg up a very high cliff and drop it (presuming that counts as bare hands), I wouldn't give the T-rex growing within much hope of survival. You could probably do this with a baby T-rex as well and you may be able to strangle or break it's neck too. Nil Einne (talk) 12:58, 26 August 2010 (UTC)

Since there are no living T-rexes, I would say no, it is not possible for a human to kill one with ANY method. Googlemeister (talk) 13:05, 26 August 2010 (UTC)

From a DYK entry on the main page early this April: Did you know... "... that T. rex survives underground in Kenya?" APL (talk) 15:14, 26 August 2010 (UTC)

Ah well those probably wouldn't pose to great a problem, though they might give you an infection if you got bit. Googlemeister (talk) 16:19, 26 August 2010 (UTC)

Would poisoning count?Smallman12q (talk) 13:52, 26 August 2010 (UTC)

I think some sort of Buffalo jump could be your best solution. But it would take some experimentation to figure out how to get it to run into the jump. If the T-Rex was a hunting predator (Most researchers think it was, at least partially, but there's some debate on the subject.), and if T-Rex is at all interested in hunting humans, you might be able to get him to chase you into the jump. You'd have to find one that a human could get down safely, but a large animal like a T-rex could not. APL (talk) 15:10, 26 August 2010 (UTC)

I think humans possess an agility and intelligence unrivalled by animals that tyrannosaurs would normally come into contact with. It don't see any specific reason (apart from complete insanity) why a human couldn't try to jump or climb onto the back of a tyrannosaur, get onto its head, put out its eyes with those dandy opposable thumbs and grasping fingers, then leave it to die a slow and (almost) pitiable death. (Boys and girls, do not try this at home. We disclaim all responsibility for rubbage upon trees, bitage by unexpectedly flexible necks, and any injuries consequent to failing to stay on the bull for the full eight seconds) Wnt (talk) 16:40, 26 August 2010 (UTC)

I was going to suggest that, but would gouging its eyes out actually kill it directly? Vimescarrot (talk) 17:05, 26 August 2010 (UTC)

Well, considering that any action which indirectly leads to the death of a person can be considered as killing them (for legal purposes, and classed as manslaughter), I would say that the person doing the gouging out of the dinosaur's eyes has, to all intents and purposes, killed it (though just not yet - (s)he'll probably have to wait for a bit while an infection of the eyes kills the animal or it runs in front of a truck or something). --KägeTorä - (影虎) (TALK) 18:11, 26 August 2010 (UTC)

Did they have a lot of trucks in the Cretaceous? APL (talk) 18:17, 26 August 2010 (UTC)

How else would these bare-handed humans get around? Vimescarrot (talk) 18:26, 26 August 2010 (UTC)

APL, no, probably not, but then, they didn't have people either. --KägeTorä - (影虎) (TALK) 18:29, 26 August 2010 (UTC)

You'd pretty much have to jump down onto it. There's no way you'd climb up one unless we're talking about a cold-blooded tail-dragging T-Rex like you see in old Ray Harryhausen movies.

It'd be like climbing onto a two-legged elephant the size of a city bus that was actively trying to eat you. Heaven help you if it turns out to be capable of rearing up vertically. APL (talk) 18:15, 26 August 2010 (UTC)

I don't know if anyone can know this, but my assumption is that the increased musculature and increased mass cancel out in terms of acceleration, and that riding a T. rex shouldn't really be any harder (!) than riding a rodeo bull. Without the leather strap, that is. Until it slams you into a wall, anyway.

Let's look at this another way. If brave Homo floresiensis could slay a Dragon of the Megalania prisca flavor, perhaps some among modern humans could do this. Wnt (talk) 18:28, 26 August 2010 (UTC)

We seem to be working VERY hard to find a way to say that the answer to this is "yes" - when it's pretty damned obvious that the answer is a categorical "NO!"...but that's the way we are here at the Ref Desk...please forgive us! SteveBaker (talk) 19:38, 26 August 2010 (UTC)

Who's we? --KägeTorä - (影虎) (TALK) 00:08, 27 August 2010 (UTC)

Hey! I still stand behind my buffalo jump idea!

If you could get a T-Rex to chase you then with careful planning you could kill him by tricking him off a cliff.APL (talk) 19:54, 26 August 2010 (UTC)

Humans are the greatest tool users on the planet! Why do you want to take away our main advantage in such a one-sided (albeit hypothetical) conflict? Googlemeister (talk) 19:42, 26 August 2010 (UTC)

A T-Rex is structurally very similar to a 50 foot long crocodile with big legs. A person with bare hands can't even kill a 10 foot crocodile, except by wrestling it to a standstill and holding on to it until it starves to death. Looie496 (talk) 23:29, 26 August 2010 (UTC)

Would it not be possible to kill a croc using some kind of choke/stranglehold? Brazilian Jiu-Jitsu and SAMBO feature several possibles in their curricula that could possibly be modified... --Kurt Shaped Box (talk) 23:44, 26 August 2010 (UTC)

There is at least one instance of a T-Rex coming to an end as a result of a Mini 1275GT and a sycamore tree.Sean.hoyland - talk 03:49, 27 August 2010 (UTC)

I could kill a T Rex with my bare hands. I just need to have a pathogen or a parasite on my bare hands or in them which would be lethal to a T Rex. Then he would eat me and soon after die. A human is to a T Rex as a cricket is to a large frog. A pet frog once got an intestinal parasite from a cricket which cause the frog's rectum/intestine to prolapse (protrude from the anus), and only timely intervention by a skilled vet sutured up the protruding intestine and saved the frog's life. There were no vet hospitals in the age of T Rex. Edison (talk) 04:58, 27 August 2010 (UTC)

"I could kill a T Rex with my bare hands. I just need to have a hand-grenade or a bazooka on my bare hands." NO! Hands with T.Rex-killing pathogens on them aren't "Bare". That's cheating! SteveBaker (talk) 23:03, 27 August 2010 (UTC)

Creationist Kent Hovind claims that the "dragons" of old were actually T. rexes and were killed by humans by ripping off their arms. And if you believe that, I just happen to have a nice steel tower in downtown Paris that I can sell for a reasonable price.Sjö (talk) 10:22, 27 August 2010 (UTC)

Haha! If he really presents that as a serious idea that's great. T.Rex's arms are comically short and stubby, but (for unknown reason) were about as strong as your average forklift. You might as well try to tear out his teeth. APL (talk) 20:09, 27 August 2010 (UTC)

If a T Rex aims to eat you, and there appears to be no way to avoid it, I recommend you yell "EAT ME!!!!" and spit in his eye. Leave the rest to pathogens in your gut and on your skin. He might curl up and die like the Martians in War of the Worlds, since he has no resistance at all to germs evolved over millions of years. Edison (talk) 01:04, 28 August 2010 (UTC)

life on other planets

Is there life on other planets. --Stephendwan (talk) 13:13, 26 August 2010 (UTC)

We don't know. See extraterrestrial life. Vimescarrot (talk) 13:42, 26 August 2010 (UTC)

It has never been proven, but we really have not looked very closely for life on any other planet except Mars (and even this search has barely scratched the surface of only a small part of the planet), and there are a lot of planets out there, so it is possible. Googlemeister (talk) 14:39, 26 August 2010 (UTC)

(edit conflict)See Allan Hills 84001 and exobiology. Remember it's not only planets that may have life. Other possibilities for life in the solar system include Europa, Io, Titan, Enceladus, and Triton. ~AH1 18:22, 26 August 2010 (UTC)

Those bodies, by any sensible definition, are planets. Well, maybe not Enceladus. --Trovatore (talk) 21:33, 26 August 2010 (UTC)

We have not found any - so we don't know. The best evidence we have is from things like the Drake equation which tries to break down the question by asking things like: How many stars are there? What proportion of stars have planets? What proportion of planets could support life? What is the probability of life spontaneously arising on any particular suitable planet? What is the probability of that life having survived until today? What is the probability that intelligence develops?

The trouble is that there are a lot of unknowns in that equation. If you ask experts in the field what their best guess for those numbers is, the answer turns out that there OUGHT to be life out there somewhere. But it's very possible that we have the answer wrong.

Another thing to consider is whether the universe is infinite or not. We don't know the answer to that question either - but if it turns out to be infinite - then it is absolutely certain that life exists somewhere - and not just any old life. If the universe is truly infinite then somewhere there are other humans - somewhere there are other humans who have developed computers and networks and have (by an astounding coincidence) created a web site called "Misplaced Pages" and that there is someone called "Stephendwan" that just asked whether live exists on other planets!!! Infinity is a very big number!

However, if life (and indeed, another "Stephendwan" exists because the universe is infinite, it doesn't help much - because only a finite amount of that infinite universe is "observable" (because the speed of light is a limitation). So the fact that the universe is infinite doesn't help to answer whether there is life that we could ever find out about, visit or communicate with...and that's really the only question that actually matters in any practical sense.

So we don't know. SteveBaker (talk) 19:27, 26 August 2010 (UTC)

Technically, if the universe is infinite (and some very natural independence properties hold yada yada yada) then it's almost certain that live exists somewhere else. That doesn't mean the probability is less than 1. A probability of exactly one is not quite the same thing as certainty. --Trovatore (talk) 23:52, 26 August 2010 (UTC)

By the same logic, if the universe is in fact infinite, the Occam's Razor is invalid, because there is an almost certain chance that the complicated answer also exists. Googlemeister (talk) 13:30, 27 August 2010 (UTC)

Occam's razor is invalid, as a statement about what propositions are true. The right way to think of Occam's razor is as a rule of thumb to guide your working hypotheses. The simpler explanation is not always closer to the truth, but it's usually the one whose shortcomings are easier to discover. --Trovatore (talk) 21:22, 27 August 2010 (UTC)

ghosts

How likely is it that ghosts exist? --Stephendwan (talk) 13:15, 26 August 2010 (UTC)

Skeptics like Randi in west and Dr Kovoor in India have setup up cash prizes to challenge the existence of ghosts, and no one has been able to win their money, they think they have triumphed - having proved for once and all there is no spook. The skeptic-flaw here is that he is assuming that the person who knows how to prove ghost will be desperate to win Randi's money ! This thought has never caught any so-called skeptic's consideration that the person with real knowledge might want to hold it as his most safely-guarded secret. This is because the modern skeptic is basically Marxist - he believes that every one does everything for wealth. The Skepticism is not scientific position, its political.

The guys who indulge in black-arts don't learn to do feats overnight, it takes years, even lives, and while at it their world-view changes, they are no longer interested in things like money or even fame, this fact is very difficult to accept for modern people, especially westerns.  Jon Ascton  (talk) 06:10, 28 August 2010 (UTC)

There is no reliable evidence for the existence of ghosts. Vimescarrot (talk) 13:42, 26 August 2010 (UTC)

How likely is it that they don't?Smallman12q (talk) 13:47, 26 August 2010 (UTC)

This discussion will ultimately lead to Argument from ignorance.Smallman12q (talk) 13:49, 26 August 2010 (UTC)

It is very unlikely that ghosts exist of the sort that you read about in books about haunted houses. Most story-book ghosts would be easily detectable by modern science. We'd have 'em in zoos by now.

The more you imagine that 'ghosts' can interact with people, (scare them, chill them, make noises, whatever) the more incredible it is that they've lasted this long with no-one proving their existence.

If your idea of a ghost is 100% unable to interact with the land of the living, then of course, there's no way we can even guess at a probability. APL (talk) 15:01, 26 August 2010 (UTC)

Any attempted scientific study of ghosts would fall under paranormal and pseudoscience. See ghost hunting, paranormal investigator and Ghost Hunters. ~AH1 18:17, 26 August 2010 (UTC)

Not at all. It is entirely possible to have legitimate scientific studies into such topics. A number of entirely legitimate researchers have undertaken to locate the Loch Ness Monster, for example. (I believe Doc Edgerton was involved in such an attempt, but I don't see it in the article, so I may be making that up.)

We mostly only hear about the complete nuts with ridiculously lax laboratory procedures because they're the only ones that have positive results. APL (talk) 18:53, 26 August 2010 (UTC)

They are about as likely as that there are Pink Piano Playing Aardvarks on the far side of the moon.

We have no way to conclusively disprove that there are ghosts - or that there are pink aardvarks. But there is also no reason to expect that either of them are true. When you come down to it, there are an infinite number of unprovable (or at least almost-impossibly-difficult-to-prove) ideas out there. That leaves you with a personal choice to make in your life:

1. Assume that all things that are not absolutely disproved are almost certainly true - and behave as if they were true.
2. Assume that all things that there is not a scrap of evidence for are almost certainly false - and behave accordingly.
3. Pick and choose which things you choose to believe in - despite there being no evidence on which to base that decision.

If you choose (1) - to believe in all unprovable things - then you'd have to believe that (for example) when you step out of your bedroom door tomorrow morning, there will be a ravenous Tiger sitting there waiting to rip you to shreds. You can't disprove that - so you are bound to assume that there definitely IS a tiger there and stay in bed. I don't think anyone can do this in practice because you'd also have to believe that a deadly scorpion is hiding in your bed and that in any case you are about to die of a symptomless, undiscovered terminal disease. You can't honestly live with (1)...it's just not possible.

If you choose (3) - to pick and choose what to believe, but without any evidence - then you may choose to believe in ghosts - but not in the tiger outside your bedroom door. The trouble is, that there are a literal infinity of things that might or might not be true - the probability that you choose correctly is quite literally zero!

So a rational person chooses (2). Disbelieve in unprovable things until there is at least some kind of evidence. Since there is no evidence for ghosts - disbelieve in them. It's the only rational way to live your life. See Russell's teapot for more discussion of this approach.

There is another little part to this. Sometimes you are forced to choose between two different courses of action, depending on some piece of information that you don't have - do you boldly step out of your bedroom door because you have no evidence that there is a tiger out there - or do you hide in your bed forever because you have no evidence that there ISN'T a tiger out there? In that case, you have to employ Occam's razor - which basically says "believe in the simplest option - unless you have evidence to the contrary". Since tigers are not endemic in Texas and I've heard no growling and there isn't a circus in town and there was no announcement of a tiger escaping from the local zoo in the news today - it's pretty safe to assume that there is no tiger waiting for me out there. I don't have proof of that - but it's the simplest explanation for what awaits me.

Oh - yeah - there is no such thing as ghosts...trust me! SteveBaker (talk) 19:11, 26 August 2010 (UTC)

There are no Pink Piano Playing Aardvarks on the dark side of the moon. Them´s Pink Floyds. --Cookatoo.ergo.ZooM (talk) 21:17, 26 August 2010 (UTC)

There are good reasons not to believe in ghosts (earthbound spirits of the departed, who appear to mortals, walk through walls, talk to them, make the air turn cold, make noises) since such phenomena are outside the system of physical and chemical principles which explain everything else in our world nicely. There is no convincing scientific evidence they exist. Neither of those is a disproof, since our understanding of science has been tweaked substantially in the past decades. The world's best scientist in 1880 had no understanding of many scientific areas every or college freshman learns about today. There could be areas of physics discovered in future years which would be as amazing to us as nuclear energy, the internet, black holes, dark matter, the Big Bang or gravitational lensing would have been to Helmholtz. There is also the strong temptation for TV producers or charlatans to fake ghost manifestations, so they earn money or gain fame. Edison (talk) 19:27, 26 August 2010 (UTC)

I've been doing a lot of reading into the subject of skepticism and belief recently. I don't think the main issue is that "irrational people" choose to believe in ghosts even tho we don't have any good evidence to support that view, like some of the above answers seem to suggest. I think the main problem is that people who do believe in ghosts also believe that we already HAVE conclusive evidence that ghosts exist, and they think WE are the ignorant or arrogant ones for not seeing it. I think they are people who simply have different standards of what qualifies as evidence, they aren't fundamentally different however. I just saw a great doco which illustrates this, it was called Dan Aykroyd - Unplugged on Ufo's. It's a great exercise in critical thinking, I recommend it. In it, there are people (including Dan) who are convinced that we are pretty much constantly visited by alien or trans dimensional beings, the governments of the world know about it and it's imminent that the whole thing will be blown open because they can't keep covering up all these sightings and abductions and stuff... It's incredible! None of those people think they don't have any evidence to support their view, they all think there's mountains of evidence. Every dirty lens, every piece of space junk filmed from ISS, every astronaut that says the word UFO during a space flight, that's all solid evidence to those people. Vespine (talk) 23:53, 26 August 2010 (UTC)

It is plainly obvious that UFOs exist. What is absurd is that UFOs are beings from another planet spying on humanity. Anything in the air is a UFO until you figure out what it is, but you don't hear much about objects that were UFOs and are now identifiable. Googlemeister (talk) 13:28, 27 August 2010 (UTC)

Carbon Excretion

Is there a way of excreting carbon from the body other than in the form of carbon dioxide in exhaled breath? Would a person doing more work and burning more energy than baseline have a higher percentage of carbon dioxide in their exhaled breath?--160.36.38.121 (talk) 17:09, 26 August 2010 (UTC)

I'm pretty sure there's carbon in urine, faeces, sweat and other excretions. When I was doing school biology many years ago we did experiments measuring the composition of exhaled breath, and the proportion of CO₂ was indeed higher after some mild exertion. (Breathing#Breathing_in_gas hints at this.) AndrewWTaylor (talk) 17:15, 26 August 2010 (UTC)

Yes, there is some carbon in nearly everything that comes out / off of the human body, but in terms of changes in human biomass nearly all of it is negligible compared to the 1-2 pounds of carbon that is in the carbon dioxide that the typical person exhales every day. Dragons flight (talk) 17:21, 26 August 2010 (UTC)

Depending on diet, a human could excrete 1-2 pounds of solid waste, which could be 50% carbon by mass. This is an ineffective sequestration method, too; and it is not a "negligible" quantity. See thousands of publications on reducing the carbon footprint of wastewater treatment (some due to energy-use, but a large percentage due to aerobic digestion of the sludge. A very significant percentage of this carbon can, through decay processes, be re-released to the atmosphere as carbon dioxide - but it is often diluted because (after treatment) the wastewater is dumped back into the environment. Diluted or not, carbon does not "disappear" - it either remains in solid form (i.e. as cellulose and all the other carbon-containing materials in human solid waste - or it is digested (by bacteria) into carbon dioxide. Nimur (talk) 18:02, 26 August 2010 (UTC)

I wouldn't consider undigested food to be "human biomass". Sorry if my wording was too subtle. Dragons flight (talk) 18:04, 26 August 2010 (UTC)

The Respiratory exchange ratio makes use of related concepts (ratio of exhaled carbon dioxide to inspired oxygen) to estimate metabolic activity. -- Scray (talk) 17:24, 26 August 2010 (UTC)

Flatulence and burping both release carbon dioxide AND methane. ~AH1 18:15, 26 August 2010 (UTC)

energy question

Humans and all living things have energy and energy cannot be created nor destroyed but can change forms but what happens when we die what happens too the energy we had. --Stephendwan (talk) 17:39, 26 August 2010 (UTC)

It's given to various other organisms via decomposition, or released as heat during cremation. Vimescarrot (talk) 18:00, 26 August 2010 (UTC)

Important distinction: "energy" in the not-created/destroyed physics sense isn't the same as "I'm feeling energetic vs tired" sense. I'm not sure if that is relevant to questioner's concern or if already knew it, etc., but I've often seen them confused in these sorts of discussions. DMacks (talk) 18:08, 26 August 2010 (UTC)

The decomposers recycle the original bodily energy back into the environment. ~AH1 18:13, 26 August 2010 (UTC)

Firstly the "Energy" described by spiritualists, fortune tellers, and the like is just superstition or, at best, metaphor.

Secondly, the energy you had is still right there, in your corpse. It's not being put to good use anymore because your body has stopped working. Imagine a broken, radio. The radio's battery still has energy, but the radio is no longer capable of using it.

Luckily your corpse will rot and all sorts of microscopic bacteria will salvage whatever energy they can. APL (talk) 18:38, 26 August 2010 (UTC)

The energy present in your body takes many forms:

1. Gravitational potential energy. When you die, you fall over - and maybe get buried in a deep hole. This energy turns into heat and gradually dissipates.
2. Thermal energy...your body is warm. When you die, that heat also dissipates out into the environment, making the world a little bit warmer.
3. Electrical energy. In your brain and nervous system - this would very rapidly dissipate into heat.
4. Chemical energy. Many of the compounds in your body are not in their lowest energy form. If you are buried underground or at sea then much of that is broken down by decomposers or perhaps scavengers - which power their bodies from the chemical energy left in yours. If you are cremated then almost all of that energy turns into waste heat. It's possible that you might be buried in such a manner that your body would not decompose very quickly - in which case, in a few million years you might form a part of a new oil reserve somewhere!
5. Mass/Energy. Someone is bound to point out that since E=mc, the atoms that make up your body have an enormous energy-equivalent. That's true - but it's most unlikely that any measurable amount of it will be released until the earth is consumed by the sun as it expands in few billion years from now - but by then, it's almost certain that those atoms will have been rearranged and used in a bazillion different ways by other processes on earth. This hardly counts!

There may be other small sources that I've forgotten - but pretty much all all of it goes to powering other organisms or as waste heat into the environment - depending mostly on how your body is disposed of subsequently.

Since this is largely a matter of entropy, a more interesting (and potentially uplifting) question is "What happens to the information content I leave behind?" SteveBaker (talk) 18:49, 26 August 2010 (UTC)

It should not be assumed that the conversion of chemical to mechanical energy by a body ends with death. It is just the voluntary movements that cease. For a considerable period after death, electrical stimulation can cause the muscles to contract, probably with a greater energy output than is required by the electrical stimulation. Think of Galvani with frog legs, or Giovanni Aldini's 1803 experiments using electricity to make the muscles of George Forster (murderer) move. Edison (talk) 19:14, 26 August 2010 (UTC)

Aurochs

When did the Aurochs go extinct on the Island of Great Britain? Googlemeister (talk) 19:50, 26 August 2010 (UTC)

The Porlock Aurochs is dated to 1500 BC, so no earlier than that. Physchim62 (talk) 20:21, 26 August 2010 (UTC)

List of extinct animals of Britain doesn't provide a reference, but suggests 1000BC. Warofdreams talk 21:25, 26 August 2010 (UTC)

According to aurochs, the last individual animal in the world died out in Europe in 1627. Of course, they're not fully extinct, as the moden ox is the descendant of the species-extinct aurochs. ~AH1 18:58, 28 August 2010 (UTC)

Sun

Can I view the sun clearly with special goggles from earth? Would I see a huge burning sphere like in pictures of the sun I've seen? Prize Winning Tomato (talk) 19:56, 26 August 2010 (UTC)

Yes, but it won't show significant detail unless you're also using magnification. Note that looking at the sun can be very dangerous; consult with someone who really knows their stuff before deciding that your goggles are sufficiently protective. — Lomn 20:18, 26 August 2010 (UTC)

This is even worse than giving medical advice. 92.28.246.5 (talk) 20:52, 26 August 2010 (UTC)

No, never do this. Danger! You could easily be blinded or pernamently damage your sight! Do not try this it is far too dangerous! The only safe way would be by projecting the image onto a screen of some kind, or by using a camera and looking at a monitor. Telescopes, binoculars or camera lenses concentrate the energy into a tiny spot on your retinas, and they will burn and be pernamently damaged. Goggles will have little effect. Have you ever tried burning something using the sun's rays and a magnifying glass - that will happen to your retinas, which are delicate. 92.28.246.5 (talk) 20:50, 26 August 2010 (UTC)

The details you want to see would be pretty much impossible to view with the naked eye - not to mention that you seriously risk damaging your eyesight by looking directly at the sun. The best way to view the sun is to use an optical device called a heliostat and a solar telescope that can project an image on to a screen. By projecting the image on a screen, you can clearly image the sun at great magnification without ever looking directly into the optical path (which would be so intense that it could permanently damage your eyesight). It is true that you can find, buy, or build a filter that can reduce the intensity to sufficiently safe levels - but if you don't know what you are doing, you risk permanent damange. Like most of science, it's a bad idea to use your own eyeballs as the "test subject" for whether a particular "goggle" / "filter" procedure is safe. Project the image on a screen. Nimur (talk) 20:52, 26 August 2010 (UTC)

Wouldn't the googles you use for arc welding work for this scenario? Googlemeister (talk) 21:06, 26 August 2010 (UTC)

This makes me wonder — how were sunspots first observed? Sunspot says that the first telescopic observations were in the 17th century, but the Chinese started observing them two millennia before. Nyttend (talk) 21:09, 26 August 2010 (UTC)

Science was not always conducted safely. Nimur (talk) 22:40, 26 August 2010 (UTC)

I used to have a piece of very dark welding glass through which it is supposedly safe to view the Sun (or at least so it was represented to me). My memory is that it was "grade 14" or something like that but I could be wrong about the exact number. In normal light it looked like a black rectangle, and if you looked through it at brightly lit objects, you could catch ghostly outlines at best.

The Sun looked like a small green disk through it. It's surprising how small the Sun appears when it's high in the sky and you're not being dazzled by it. I used it to look for sunspots at a time of supposedly high sunspot activity, and I did see a few, I think, but I can't say the sight was all that spectacular given the small apparent size. --Trovatore (talk) 21:15, 26 August 2010 (UTC)

All reputable sources will tell you not to rely on a filter. The problem is that in the old days, a child's first telescope would come with a cute little "Sun" filter to screw in. And every once in a while someone would watch for so long, that the filter would crack and suddenly let through super-hot concentrated light from the telescope, precisely focused on the child's retina.

Now speaking as a child who used such a device in blissful ignorance, it was a cute little toy, and you could see the sunspots, but the sun was a plain bright disk. (Actually, not all that bright - I think now and then I might have used the little "Moon" filter instead to get a better view. Miracle I have two eyes) The sun looked green because of the filter; no true colors were discernable. Things like the corona and prominences - don't even think about it. You could get a better view anyway by projecting the image onto a white surface far from the telescope.

Now obviously, wearing a welder's mask and looking straight on at the full sun, without magnifying aids, is pretty darn safe. Believe it or not the eye was actually adapted to look in the direction of the sun now and then. Looking at the sun during an eclipse is more dangerous because the light isn't very bright and your irises open up, but the light is just as concentrated in the area not blocked by the moon and the cells directly under the remaining crescent get scorched worse than if you stared at the sun normally. Wnt (talk) 21:44, 26 August 2010 (UTC)

Until you learn how to make a pin hole projector, or find some welding goggles just go here, awesome pictures almost in real time, taken in different spectra taken by SOHO. There's a half decent spot there now, first one I've seen for a while, it has been the Sun's quiet period for the last few years. Sorry but no, you won't see anything like that with your eyes. Pictures of anything astronomical you see are usually either taken with massive professional telescopes, space observatories, or worst of all "artists renderings".. LOL! Actually, come to think of it, they're like the playboy covers of the astronomy world, i never thought of it like that but that's a funny analogy. They're all photoshopped and stuff, it gives everyone an unreasonable expectation of what it really looks like ... lol.. Vespine (talk) 22:56, 26 August 2010 (UTC)

To be fair, the Sun's actually a much 'easier' target than most other astronomical objects. Having both large apparent size and extreme apparent brightness, getting very good images of the Sun (at least, at wavelengths that will pass through the atmosphere) requires equipment that is costly but not out of reach of the (very) dedicated amateur. Unlike faint, dark-sky objects like nebulae and distant galaxies, one does not need a large-aperture telescope or hour-long exposures to gather enough sunlight for a striking photograph. Using Meade's Coronado Personal Solar Telescope (500-1000 USD from the manufacturer), which has a 40 millimeter aperture (about an inch and a half), you can get raw images like this. A good camera, good technique, and careful processing can use the same instrument to extract images like these(!). If you're willing to cough up five to ten thousand dollars, then you get to the high end of commercially-available dedicated solar telescopes. These stunningly detailed images were captured using a 90 mm aperture scope with a very good set of filters.

As Vespine notes, however, the published images that you see of virtually any astronomical object, the Sun included, will be vastly superior to what you see at the telescope eyepiece. Multiple exposures are taken, and ones with poor detail due to atmospheric disturbances ('poor seeing') can be discarded. Shorter and longer exposures are taken sequentially and digitally combined, so that bright objects aren't overexposed but faint objects become visible. Contrast is adjusted to make details stand out. For solar images, false color is almost always used. (The hydrogen-alpha filter used for the images I've linked only passes a small amount of red light; the images are then recolored in shades of yellow to look more 'Sun-like', or using a ramp from black→red→yellow→white to give more apparent dynamic range and make features 'pop'. You can see the red spot on the eyepiece lens in the first link I provided; that's the only color that comes through an H-alpha filter.) TenOfAllTrades(talk) 13:54, 27 August 2010 (UTC)

I 100% agree that you must avoid looking at the sun directly and goggles are not a safe bet. So, here is what you do. You find a room in your house where it's fairly sunny at a particular time of day - and which (preferably) has only one window. Now you need to almost completely black out the window - either with very thick curtains - or perhaps some black construction paper or cardboard...shut the doors and ideally, the room is now very dark. Let your eyes adapt to the darkness for a while and then cut about a 1" hole in the cardboard and tape over that a square of kitchen foil. Now, with a pin, poke a pinhole into the foil to admit a thin stream of sunlight. Take a piece of white paper and let the stream of light fall onto it. You should be able to see a small picture of the sun. This is perfectly safe to stare at without goggles. You can move the paper closer or further from the pinhole to get a smaller/larger image...but the bigger you make it, the dimmer it will be. If you want a larger, brighter, image you can enlarge the pinhole slightly and move the paper "projection screen" further back. If you can get the room nicely pitch dark - and if it's a clear, sunny day - the results will be pretty amazing. You can even use a camera to take pictures of it - although you'll need to turn off the flash and get the right compromise between size and brightness. SteveBaker (talk) 22:49, 27 August 2010 (UTC)

There are certain solar "eclipse glasses" that you can buy that are designed to filter out the sun to a safer brightness. However, sunglasses are NOT safe for this purpose, and using binoculars or a telescope while wearing these glasses can cause the material to be burnt through! Another safe method is using a full-aperture solar filter or a specially-designed amateur-use solar telescope to view the Sun through a telescope, but one hole in the filter can ruin your vision, and the eyepiece filters for the sun can crack and are NOT safe! Finally, #14 arc welder glasses, at least two sheets of unused X-ray sheets, or pinhole projection are also safe ways to view the Sun. However, there is a danger even in using a telescope, binoculars or a magnifying glass to project a focused image of the Sun, as that can burn your retinas if you stare at the image too long, and can even burn the material it is projected onto especially paper. ~AH1 18:53, 28 August 2010 (UTC)

Clock

When the seconds hand on a analog clock is rising back to the 12, gravity acts upon it. Will putting the clock on its back (thus removing the gravitational effect on the seconds hand as it both rising to the 12 and falls to the 6) cause the clock to become inaccurate? Prize Winning Tomato (talk) 19:57, 26 August 2010 (UTC)

That depends on the design of your clock. If it's a pendulum clock then yes, putting it on its back will cause it to become very inaccurate! If it's a modern electrical clock driven by the vibrations of a quartz crystal, it should have any great effect. Physchim62 (talk) 20:24, 26 August 2010 (UTC)

Not significantly†. Note that some clock designs don't work if you lay them sideways, but that's not because of gravity acting on the arms. — Lomn 20:27, 26 August 2010 (UTC)

†Given the millions of various clock designs out there, I'm sure you can find one somewhere that is so poorly designed and constructed as to drastically change its timekeeping under this scenario. For practical purposes and the general case, though, the answer is "no". — Lomn 20:27, 26 August 2010 (UTC)

Sometimes (often) the arms are conterbalanced - they stick out a little in the other direction. In other cases they are so light the clock motor has no problem moving them. In a mechanical clock difficulty in moving the hand may slow the clock, but in a quartz mechanical clock it doesn't - the timekeeping continues, it just signals the motor to move, and then continues counting, it doesn't wait for the motor. Ariel. (talk) 20:50, 26 August 2010 (UTC)

Even if it's strictly analog, and even if the hands aren't counterbalanced, I think there would be at most a transient effect, offset later for no net effect. Gravity is a constant, so whatever slowing-down (force lost against gravity) it would cause the minute-hand on the rising route 6→12 would also give a speeding-up on the falling route 12→6 (gravity boosts/reinforces motion). So the first half of each hour would be slightly shorter while the second half slightly longer. But if you're integrating over a closed cycle, the path doesn't matter--no overall change, every hour is the same total length (albeit strangely paced!). It's like a pendulum or a bouncing ball: speeds up every down-motion, slows down every up-motion. Otherwise there's a conservation-of-energy problem (and a perpetual-motion-machine opportunity!). DMacks (talk) 21:21, 26 August 2010 (UTC)

Are you sure that works? If it slowed down in the after-6 position, it would spend more time on that side of the clock than on the before-6 side. If it spent 31 minutes on the slow side of the clock, and 29 minutes on the fast side, wouldn't it gain four seconds an hour? (Assuming the fast side loses 2 seconds per minute and the fast side gains 2 seconds per minute.) APL (talk) 22:00, 26 August 2010 (UTC)

Why would the fast side (but not the slow side) lose 2 seconds per minute and the fast side (but not the slow side) gain 2 seconds per minute? Are you thinking the second-hand is going faster on one side vs another? My same argument holds there...the second-hand makes a complete circle every minute, so the minute may be asymmetric, but it's still 60 seconds overall. DMacks (talk) 00:13, 27 August 2010 (UTC)

Because in this context that's what "fast" means it's not "fast" unless it's gaining time!

It's not symmetric because whichever hand has the problem will spend more time going too slow than it spends going too fast. Imagine the extreme case where the problem is 2X. The minute hand would spend 15 minutes on the fast side, and 60 minutes on the slow side for a total of 75 minutes per hour. APL (talk) 01:14, 27 August 2010 (UTC)

I assumed force added/subtracted a constant rather than acted as a multiplier/divider--gravity as a vector not a gear-ratio effect and torque/work/etc all are in terms of distance of the action not the time it's acting. DMacks (talk) 08:34, 27 August 2010 (UTC)

Hmm.. You're right, that's probably more likely than my way. Ok, we're going to need a defective clock to settle this. APL (talk) 19:50, 27 August 2010 (UTC)

That all assumes a rigid mechanism connection (gears, pulleys, etc.) If you add ratchets or other non-linear-mechanical controls (not quite sure what the right term is for these), then you could have all sorts of weird effects. Consider putting the minute-hand on a ratchet: as soon as it crosses over 12, it falls right to 6. As soon as the next catch in the ratchet picks up, it goes back up to 12 at normal speed (with gravitational or whatever else influences). That's a dumb idea...most hour-long meetings start "on the hour", and if anything I'd want the second half to fly by rather than the already-dragging second half:) DMacks (talk) 21:20, 26 August 2010 (UTC)

"Escapement" may be the word you want. How does an Omega watch work? Well, there are loads of tiny parts to account for all these sorts of things - like when the watch is upside-down, or moving, or swinging around on a hand; or when the spring winds down and the force is a bit less than it used to be; and so on. The tourbillon is the specific part that compensates for gravity (and is considered superfluous in most high-quality designs). The very word "clockwork" has come to be synonymous with "lots of complicated internal parts that carefully compensate for small details." A modern electric clock uses a motor and a quartz timer, and a bunch of mechanical ratchets, gears, and escapements. It uses extra energy (but a miniscule amount) to move hands forward; and the hands catch on the next ratchet or catchment, guaranteeing that regardless of position, each "tick" is a progression by the same amount. The deviation from "ideal" can be measured to ~ 1 part in 10 on a modern clock; and more expensive clocks are even more accurate. Nimur (talk) 22:11, 26 August 2010 (UTC)

Cool pics. I definitely think Tourbillon#Mechanism of Action addresses the OPs question. Wikiscient (talk) 06:11, 27 August 2010 (UTC)

WP:OR I once had a very long layover in Heathrow Airport on my way through London to Beirut. To pass the time, I went to the Schaffhausen store, and stared at watches that cost more than my plane ticket - and watches that cost more than my car; I was truly dumbstruck. (One of the rare times in my life when I couldn't think of something to say). And a man approached me - not the salesman - but an out-of-work and formerly-famous rock star - and he told me that he understood my confusion, as I stared at watches that nobody could afford. I told him how I had worked on engineering projects where we used software and electronics to accurately measure time to sub-nano-second precision; how I couldn't understand why a lousy gear-mechanism based on technology from 1759 would have any market value. And the watch-enthusiast rock-star replied by explaining the complexity of these watches; and how they were not only about technology, but about priorities in life - that sometimes we do things in life not because they are practical, but just because we can. I think he's still unemployed, but he probably lives on some Greek island in the mediterranean with three yachts and a $90,000 7-jewel watch, anyway. Nimur (talk) 16:01, 27 August 2010 (UTC)

Just a couple of observations ... I've seen numerous clocks that spend 31 seconds on the "up" side and 29 seconds on the "down" side, but they still keep accurate time (of course I don't know what APL meant). I've seen other battery clocks with weak batteries where the weight of the second hand on the "up" side causes the escape mechanism to miss a "tick" and thus the clock loses time (before stopping completely). Dbfirs 13:17, 27 August 2010 (UTC)

reading from your peripheral vision

alight and fix your eye on the first word of the next sentence, and try to read the rest of it from your peripheral vision. When I do that I clearly fully see the whole rest of the sentence, so that it seems I would be able to read it without an issue, but of course I can't. I couldn't actually sound out the sentence that it seems to me I easily could have! So, it seems to me there are two possibilities: the "clear image" is a lie by my brain. I sense those words clearly, but the brain is just giving me a general idea of "clear" based on the shapes it sees: it can't really read from the peripheral vision. (so all those clear words are lies, just as what your brain paints into your blind spot is). The second possibility I can imagine is that it is not a lie on the part of my brain that I see those words clearly; I do and with training I can read them without moving my gaze to them.
So, which of my conjectures (if either) is correct? 85.181.50.8 (talk) 21:12, 26 August 2010 (UTC)

As this is the science desk I'd like to propose an experiment. Can you read text in your peripheral vision if the font size is large enough that you're absolutely sure you can resolve it? APL (talk) 21:16, 26 August 2010 (UTC)

Sorry, I'm on a phone right now. Can you? 85.181.50.8 (talk) —Preceding undated comment added 21:30, 26 August 2010 (UTC).

Nah, I'm a bit busy. But when you get off the phone you might want to check out the Vision span article. APL (talk) 21:47, 26 August 2010 (UTC)

My guess is that's it's a mixture of your two explanations. Peripheral vision is less precise than central vision, but it is good enough to recognize large single word shapes for most people under the age of 40–50 (and many who are older than that). You could probably do better if you trained yourself – maybe that's one of the things they teach you in spy school – but most people learn to read by looking directly at the text. However, your peripheral vision is not as clear as you think it is (because your brain tends to "fill in the gaps") Physchim62 (talk) 23:04, 26 August 2010 (UTC)

It's closer to the truth to say that the "clear image" is a lie -- except really it's more a lie by omission than an overt lie. In other words, we are predisposed to presume clarity unless we specifically detect fuzziness. As long as something is as sharp as our eyes can resolve, it looks perfectly sharp to us. Regarding the ability to read with peripheral vision, it is extremely poor -- the letters have to be about 10 times as large as usual if they are more than a few degrees outside the fovea. The region of clear vision is roughly the size of your fist held at arm's length -- the dropoff in resolution is not abrupt but it is very rapid. It is indeed remarkable that we have so little conscious awareness of this radical change in our visual capabilities so near the center of our field of view. Looie496 (talk) 23:18, 26 August 2010 (UTC)

The central part of your eye is the only part with sufficient resolution to read small print, the rest of the eye has lower resolution - but it makes up for it by being much more light, and motion, sensitive. You can test it by setting your CRT monitor (if you still have one) to a 60hz refresh rate. Next look at it straight on, and it's pretty steady, but look at it from the side of your eye and it will flicker (if you don't have a CRT try to find an old fluorescent light, or maybe even a slow fan). A second test is in poor light - from the side of your eye you see more light than from the center. It's usually very hard to tell that the sides of your eyes don't have a lot of resolution because the eye is so good at rapidly flicking in all directions to give you a good view in all areas. Ariel. (talk) 01:28, 27 August 2010 (UTC)

Or, if you'd prefer to just not bother with having anything in the periphery to read, you could look into Rapid Serial Visual Presentation#Notable Products. You can improve your reading speed by about a third that way (note drawbacks though). Wikiscient (talk) 05:37, 27 August 2010 (UTC)

An interesting way to demonstrate how your mind makes up most of what you see in your peripheral vision based on what you expect is to get some coloured sticks/pens/pencils and get someone to move them into your field of sight from behind you as you continue to look straight. If they ask you what colour it is when you don't know it'll take a while for you to accurately work it out, but if you know it is a certain colour, you'll be able to tell sooner. Smartse (talk) 11:52, 27 August 2010 (UTC)

You might also be interested in the semantic priming and saccade articles. Wikiscient (talk) 06:14, 28 August 2010 (UTC)

When I look at the spot proposed by the OP, all I clearly see is "When I do that I clearly fully the sentence that it seems to me giving me a general idea of spot is the second them". ~AH1 18:42, 28 August 2010 (UTC)

August 27

Lard as sunscreen...?

Sometimes you see characters in older cartoons and sitcoms smearing themselves with lard when sunbathing, instead of sunscreen. Obviously it's done on there because it looks funny - but did (do?) people ever actually do that in real life? Does lard, in fact protect the skin from the effects of UV radiation? --Kurt Shaped Box (talk) 00:07, 27 August 2010 (UTC)

Did people actually care about sunscreen back then? Or was it just a moisturizer/conditioner/etc, like one might use baby-oil or SPF-0 now when trying to get a dark tan? DMacks (talk) 00:23, 27 August 2010 (UTC)

Dunno, to be honest. I've met people who think that baby oil *is* a sunscreen. --Kurt Shaped Box (talk) 00:34, 27 August 2010 (UTC)

It's not a sunscreen its a suntan lotion. That is, there are products which intensify the tanning effect of the sun, or can be used as moisturizers to combat the peeling and drying from excessive sun exposure. The use of baby oil and lard is likely more for these effects (as in, "fuck cancer, I want a good tan"...) --Jayron32 02:23, 27 August 2010 (UTC)

Agreed, lipids won't block UV radiation, if they did, there would be no need for sunscreen. Here's a funny article where someone asked if salad dressing worked as sunscreen! My mum's told me before that in the 60s plenty of travellers in Greece used olive oil and sunbathed and, unsurprisingly, went redder than tomatoes. _{Are mothers a reliable source?} Smartse (talk) 11:48, 27 August 2010 (UTC)

What is the wind-water-solar climate change mitigation scenario atmospheric carbon projection?

In Jacobson, M.Z. (2009) "Review of solutions to global warming, air pollution, and energy security" Energy and Environmental Science 2:148-73 doi 10.1039/b809990c and Jacobson, M.Z. and Delucchi, M.A. (November 2009) "A Plan to Power 100 Percent of the Planet with Renewables" (originally published as "A Path to Sustainable Energy by 2030") Scientific American 301(5):58-65 what is the projected atmospheric carbon over time for their preferred wind-water-solar program?

What year do they start subtracting carbon and when do they reach 350 ppm?

I have asked also here, but I have been having better luck here at WP:RDS. Why Other (talk) 02:04, 27 August 2010 (UTC)

Per Dr. Jacobson, this is related to Eqn. 3 in http://www.stanford.edu/group/efmh/fossil/ClimRespUpdJGR%201.pdf

" the time-dependent change in CO2 mixing ratio from a given anthropogenic emission rate, the time-dependent difference in mixing ratio resulting from two different emission levels by subtracting results from the equation solved twice. Note that chi in the equation is the anthropogenic portion of the mixing ratio (this is explained in the text) and units of E need to be converted to mixing ratio. The conversion is given in the paper."

This almost might be ready for the math reference desk. Why Other (talk) 22:18, 27 August 2010 (UTC)

Maybe something like the scenario proposed by James Hansen's Alternative Scenario paper? ~AH1 18:38, 28 August 2010 (UTC)

Sam and Ella over easy

In news reports about the recent salmonella outbreak in US eggs, they mention that people should avoid having lightly cooked scrambled eggs or eggs over easy. I haven't heard one yet advise not to have sunny side up and I would think that that would be more dangerous than over easy. Am I right in thinking that sunny side up would be more dangerous than over easy? Dismas| 02:25, 27 August 2010 (UTC)

Sunny side up is less cooked (heated) than over easy, so it would be less likely to kill bacteria, yes. -- Scray (talk) 03:06, 27 August 2010 (UTC)

I know it would be bad for the egg industry which is no doubt already going to suffer a big hit because of this, but wouldn't you just stop eating eggs for a few weeks? Having said that however, that does remind me of how Oprah got sued for saying she wasn't going to eat beef during the mad cow incident. Vespine (talk) 04:05, 27 August 2010 (UTC)

It won't keep me from eating eggs. We get ours from our own chickens. 25 birds with more room than was in my first house! Dismas| 13:35, 27 August 2010 (UTC)

Eggs are quite safe to consume (even contaminated ones), provided they're cooked properly. In this regard, they're no different than meat, and there's no reason to not consume them just because they might have salmonella. Personally, I always treat my eggs (and meat, especially ground meat) like it's contaminated. I think that it really speaks to how good our public health system (generally) is, that people now expect their eggs to be free of pathogens. Buddy431 (talk) 20:51, 27 August 2010 (UTC)

"Over easy?" I beg your pardon? As a non-American, I think I've just discovered another entry for List of American words not widely used in the United Kingdom. (Even though it's actually two words.) Can some one explain what it means please? HiLo48 (talk) 22:03, 27 August 2010 (UTC)

See Over_easy#United_States_and_Canada: It's a fried egg which cooked on both sides. Hence "over"...you have to flip it "over" during cooking. The yolk is left very runny and even the white is somewhat liquid inside the solid white 'pouch' formed by cooking it on both sides. And "easy" is the opposite of "hard". You could theoretically ask for your eggs "over hard" or "over medium" too - but I've never heard anyone actually do that. If you just asked for "fried" you get it fried on just one side. The myriad of only marginally different ways that Americans like their eggs cooked is guaranteed to perplex us poor Brit's the first time we undertake breakfast at "Dennys". SteveBaker (talk) 22:31, 27 August 2010 (UTC)

My mother always used to ask for "two eggs over medium". I haven't heard her do that in a while. But maybe I just haven't had breakfast with her in that sort of place for a while.

The one whose definition I've never been quite sure of is "sunny side up". I think that means the cook is supposed to spoon some of the hot fat on top of the egg, so that even the top gets a little bit cooked. But I don't know whether they all bother. --Trovatore (talk) 23:05, 27 August 2010 (UTC)

Once again, Fried Egg#United_States_and_Canada comes up with a definition: "'Sunny side up' — cooked only on one side; yolk is liquid; the egg white is often still a bit runny as well. This is often known simply as 'eggs up'. Gently splashing the hot cooking oil or fat on the sunny side uncooked white, i.e., basting, may be done to thoroughly cook the white. Covering the frying pan with a lid during cooking (optionally adding a cover and half-teaspoon of water just before finishing) allows for a less "runny" egg, and is an alternate method to flipping for cooking an egg over easy (this is occasionally called 'sunny side down')." SteveBaker (talk) 23:41, 27 August 2010 (UTC)

Sourdough starter

A recipe in a book on baking says to make starter for sourdough rye bread by mixing beer with rye flour in a mixing bowl, then covering the bowl with plastic wrap for 2 days at room temperature, beating it 3 times per day. It is supposed to bubble and smell sour, but is has not changed from hour one in 2 days. I thought sourdough relied on yeast from the air somehow entering the mix and multiplying. If the starter is covered by plastic, oxygen would be restricted and nasty anerobic bacteria would seem to be favored. Also how would environmental yeast get into the mixture? Would rye flour contain yeasts? Would beer (soon stale due to loss of carbon dioxide) furnish a culture to leaven the sourdough? The recipe does specify using yeast in addition to the sourdough starter when the dough is finally made. I have a sourdough starter of considerable longevity and vigorous activity which I use for regular bread baking, although with ordinary all-purpose wheat flour or bread flour. Would it make sense to add some of this to the rye flour/beer mixture? Edison (talk) 04:44, 27 August 2010 (UTC)

Some beers have got the same stuff, anyway: Saccharomyces cerevisiae What kind of beer are you using? Wikiscient (talk) 06:02, 27 August 2010 (UTC)

Are you using an unpasteurized beer? Something like Creemore Springs lager should do the trick, or any beer that is bottled with live yeast. The yeast will be dormant by the time you get it but will reactivate with a new food source. Industrial beer probably won't (and shouldn't) get the job done. Franamax (talk) 07:25, 27 August 2010 (UTC)

The recipe says as an alternative to beer to mix rye flour and water and cover with plastic for 2 days, beating 3 times per day, so they do not seem to be relying on yeast from the beer. Some recipe sites say that rye flour contains some natural yeast. The plastic wrap cover concerns me as stated above, and a cloth over the bowl seems to make more sense, to allow in some air. After 2 days and no foam, I fed the stuff with more flour and some water, then divided it in half and added some of my usual starter to one batch. The usual starter has been fed for years with milk, all purpose flour and sugar. Starters are supposed to be a combination of yeast and anerobic bacteria, with some complex conversions taking place to the raw materials. I just thought someone might have experience with or knowledge of establishing a rye flour starter. Edison (talk) 16:41, 27 August 2010 (UTC)

Sourdough starters are basically dough based cultures containing yeast and bacteria such as Saccharomyces cerevisiae and Lactobacillus acidophilus. Both types of microorganisms and their spores are found floating in the air and environment so there is likely some already in the rye flour. Since starters are just bacterial and yeast cultures, I think you can innoculate your rye flour/beer mixture with it to assure yourself higher success in making your rye starter. In fact, I would forgo making the rye starter and just use your bread flour starter for rye bread. -- Sjschen (talk) 17:02, 27 August 2010 (UTC)

There are many kinds of yeast and each gives a different flavor, so this wouldn't automatically give the same result. Looie496 (talk) 17:30, 27 August 2010 (UTC)

mechanics

. Two forces are applied at two different points on a thin rigid rod ; the two points could be the end-points of the rod. Using equilibrium conditions prove that for the rod to be in equilibrium , the direction of forces must be collinear with the rod. —Preceding unsigned comment added by Khushal13 (talk • contribs) 05:10, 27 August 2010 (UTC)

Sorry, we don't do homework for you, but that said, do you understand the question? Especially do you understand what equilibrium, and collinear mean? Because once you do the answer should be easy. Ariel. (talk) 06:43, 27 August 2010 (UTC)

... but if you still haven't answered your question, perhaps our article on Moment (physics) might help. Dbfirs 12:03, 27 August 2010 (UTC)

If they were not collinear and opposite, wouldn't the rod tend to rotate or move? Edison (talk) 01:09, 28 August 2010 (UTC)

know

how to spell knownen like a knownen carcinogen? —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 05:30, 27 August 2010 (UTC)

1) This isn't a science question. 2) Try a dictionary like wiktionary e.g. wiktionary:Special:Search (yes I've tried and it works). In any case, it seems you've already answered your question. Nil Einne (talk) 06:03, 27 August 2010 (UTC)

It's just "known" like "known carcinogen". Wikiscient (talk) 06:24, 27 August 2010 (UTC)

White onion

What is the latin name of white onion? --Ksanyi (talk) 07:43, 27 August 2010 (UTC)

I believe that it's Allium cepa, but I'm not sure it's the only species of white onion. Someguy1221 (talk) 09:14, 27 August 2010 (UTC)

Mars drill

It would seem to me, that if Mars ever supported life, any traces of it would be deeply buried under its surface; so why not drill into it, or even easier, use explosives, to probe into deeper layers ? Or has this been done already ? —Preceding unsigned comment added by Rowen121 (talk • contribs) 08:36, 27 August 2010 (UTC)

This was the point of the Deep Space 2 mini-probes carried aboard the Mars Polar Lander (though whether you'd consider 0.6m "deep" I don't know); sadly, while (unlike MPL) they did successfully get to the surface they never "phoned home". --81.158.2.129 (talk) 10:07, 27 August 2010 (UTC)

"Our mission: to seek out new life ... and vapourise it". Gandalf61 (talk) 14:59, 27 August 2010 (UTC)

Mars has an atmosphere that contains water vapour and various chemicals so do not rule out the possibility of above-ground flying organisms. Cuddlyable3 (talk) 15:16, 27 August 2010 (UTC)

This is the same reason that the Mars rovers sought out craters on the Martian surface (preferably "recent" craters). Those cratering events are much more powerful than any explosion we could afford to send and thus hopefully probe deeply and dislodge a lot of buried material. I have also seen NASA technology development grants offered to people wanting to build a drill for space operations, but the size, complexity, and power requirements of such systems tend to be prohibitive. Dragons flight (talk) 15:24, 27 August 2010 (UTC)

There has been a lot of work on developing deep-drilling technologies for Mars exploration -- if you do a Google Scholar search for "Mars drill" you'll get a few dozen papers. I believe that a European probe that is already under construction is intended to be able to drill 2 meters deep; it can be expected that future probes will go quite a bit deeper. Looie496 (talk) 16:02, 27 August 2010 (UTC)

Subsurface exploration is difficult on Earth - and it's even harder in space. For historical perspective, you can read about profiling the lunar subsurface on Apollo 17. Getting underneath the soil is really hard. Drilling is difficult - it takes a lot of energy. Blasting is difficult - it requires dangerous chemical explosives, and these are consumables (so you only have a certain number of shots). If you can think of a different way to remove large amounts of dirt, NASA would love to hear about it: every year they hold a Lunar Robotics Mining Competition. Mars' soil is quite different than lunar regolith (and both are quite different from Earth soil) but the basic task is about optimizing parameters: how many kilograms of dirt; how many cubic meters of dirt; and how fast, how many joules of energy, what forms of energy (battery, chemical, solar, and so on). Nimur (talk) 16:33, 27 August 2010 (UTC)

The Beagle II probe carried a 'robotic mole' that was designed to tunnel around. (More like an earthworm than a mole, really.) Unfortunately, Beagle II did not successfully make a controlled landing. APL (talk) 19:54, 27 August 2010 (UTC)

Right with the European probe! It is ExoMars. The system will carry a 4 X 50cm drill which was already tested in a Mars chamber here on earth. Two meters into hard rock will be a big step in the understanding what the atmosphere does to the surface of Mars. The drill is a upgrade from the drill already under way to 67P/Churyumov-Gerasimenko. The first sample will not be delivered before 2019. I heared from MSL scientists that they envy us for the nice drill we get.

Who invented Galvani cell (aka galvani element)?

Who would be rightfully credited inventor of Galvani cell, is it Galvani or Volta or both of them or sbody else entirely?

Difference between Voltaic cell and Galvanic cell is also a bit vague to me... —Preceding unsigned comment added by Pudist (talk • contribs) 11:58, 27 August 2010 (UTC)

See the article Voltaic pile. A voltaic pile is a set of individual Galvanic cells placed in series. Luigi Galvani 1737 - 1798 and Alessandro Volta 1745 - 1827 were rivals as noted at Luigi Galvani#Galvani vs. Volta: animal electricity or heat electricity? and Alessandro Volta#Volta and Galvani. A "Voltaic cell" is a split Galvanic cell used for demonstrations. Cuddlyable3 (talk) 14:17, 27 August 2010 (UTC)

Velocity and acceleration

Overheard this on bus from what I assume to be two freshman college students... "This class sucks. We are given three mile markers and times and we are supposed to tell the car's velocity and acceleration. He doesn't tell us which method to use to calculate it, so I'm sure I'll get it wrong." Given three positions on a line with the time for each position, are there really many different methods to calculate velocity and acceleration? I can only think of dividing distance by time for velocity and, because there are three positions, subtracting the first section of velocity from the second section. -- kainaw™ 12:13, 27 August 2010 (UTC)

That's the only way that comes to mind for me too. Now granted, there are thousands of wrong ways...using constants that don't apply, mixing incompatible/unconverted units of measurement, plugging loose numbers into unrelated formulas, etc. So I'd say the odds are actually strongly favor getting it wrong. Assuming they didn't actually just pay attention in class or read the text. Which again the odds seem to strongly favor. DMacks (talk) 12:20, 27 August 2010 (UTC)

I imagine that's the intended solution, but strictly it would only work out the average velocities at the half mile points and I wonder if it's meant to be a little more sophisticated than that (hopefully, if it's college-level, it is?). I think there's enough information in the problem to use the suvat equations under the assumption of constant ${\displaystyle a}$.

We have three pairs of distances/times ${\displaystyle (x_{1},t_{1})}$, ${\displaystyle (x_{2},t_{2})}$ and ${\displaystyle (x_{3},t_{3})}$. We can apply ${\displaystyle s=ut+{1 \over 2}at^{2}}$ to the differences between any two pairs of these to get a pair of simultaneous equations in two unknowns ${\displaystyle u}$, the initial velocity and ${\displaystyle a}$, and then just use ${\displaystyle v=u+at}$ if we're desperate to know the final velocity explicity too, e.g.:

${\displaystyle (x_{3}-x_{1})=u(t_{3}-t_{1})+{1 \over 2}a(t_{3}-t_{1})^{2}}$

${\displaystyle (x_{2}-x_{1})=u(t_{2}-t_{1})+{1 \over 2}a(t_{2}-t_{1})^{2}}$

All the ${\displaystyle x}$s and ${\displaystyle t}$s are given so it's a lot less hairy once they substitute the numbers they've got. There's bound to be a flaw in my logic somewhere, though.

--12:49, 27 August 2010 (UTC) —Preceding unsigned comment added by 81.158.2.129 (talk)

Eliminate t₁ and x₁ which can both be zero. We are given x₂ = 1 mile and x₃ = 2 miles. So far, so good. Go ahead and solve v = f(t₁,t₂,x₁,x₂) and a = f(t₁,t₂,x₁,x₂). Cuddlyable3 (talk) 14:29, 27 August 2010 (UTC)

Yeah, I was hugely overthinking that with all that simultaneous equations guff. For the constant acceleration case it just boils down to solving the equation of a parabola, given three points ... --217.41.233.67 (talk) 15:10, 27 August 2010 (UTC)

Somebody (the student or the professor) has forgotten to state the implicit assumption of constant acceleration. If this is not specified, the problem is unsolvable (any high-order function that fits three points is acceptable). If constant acceleration is specified, this is a trivial parabola-fitting problem that can be solved on paper (or with a calculator if the numbers are ugly). Nimur (talk) 16:36, 27 August 2010 (UTC)

A likely name for a science fictional superhard material

I've come up with the slapdash 1,8-Bis(hydridol)carbyne - but I have a strong feeling it's a neologism that would make a materials scientist laugh then vomit - can someone suggest something just as impressive-sounding but that would make a lick of sense to a scientist?

Thanks Adambrowne666 (talk) 12:18, 27 August 2010 (UTC)

It sure sounds technical though, maybe that's the only important part? From what I've seen, scientists are probably going to spot the fiction pretty easily anyway even if the name is correctly formed or scientifically valid--if they care to think about it at all--and nonscientists are going to be impressed with something technical-sounding even if it doesn't have any sensible meaning. DMacks (talk) 12:27, 27 August 2010 (UTC)

You could call it, say, hydridol(II) carbyne, a compound of hydridol and carbyne where hydridol has an oxidation number of 2. Hydridol and carbyne could be some as-yet undiscovered elements. Although a real scientist would know there is no gaps in the periodic table, so they would have to have huge atoms and likely be radioactive. Do whatever you like--178.167.206.113 (talk) 14:09, 27 August 2010 (UTC)

Any plausible superhard material would have a tradename or, at the very least, a nickname that scientists use for it (a bit like "magic acid"). Physchim62 (talk) 14:19, 27 August 2010 (UTC)

You could borrow from the Dune universe some Plaz, a synthetic glass, used for windows (especially in aircraft and spaceships) due to its superior strength, or some Shigawire which is a metallic extrusion of a ground vine (Narvi narviium) grown only on Salusa Secundus and III Delta Kaising. It is noted for extreme tensile strength and used as a recording medium (among other things). Shields (Star Trek) are reportedly generated by replication of an alloy of diburnium and osmium, the hardest alloy known to the Federation. Cuddlyable3 (talk) 15:03, 27 August 2010 (UTC)

From a scientific point of view, there's no way to get anything much harder than diamond using ordinary chemical bonds. The only real possibility for getting a superhard material would be to go to the nuclear level. If I were writing about something like this, I would use quarkonium, a substance made from neutronium by getting the neutrons to share quarks. I think even a particle physicist would have difficulty automatically ruling that out. Looie496 (talk) 15:49, 27 August 2010 (UTC)

It depends on how hard the material should be. There are many carbides, tungsten carbide, tantalum carbide, and rhenium carbide (need an article on that last; cute stuff). And diamond is "carbon carbide", you might say. It is very well plausible that by forming exactly the right matrix of this metal and that metal in just such-and-such a configuration, you can get something that would eat diamonds for lunch, drill bit to drill bit that is. Wnt (talk) 18:43, 27 August 2010 (UTC)

Again borrowing from Sci Fi, Unobtainium, unless you are after the chemical name. 220.101 talk 20:06, 27 August 2010 (UTC)

Is there a specific reason you don't want to make material scientists vomit, are they likely to be a large group of your readers? I second a 'carbide' as they're popularly known to be hard. The first time I saw the word 'unobtainium' used seriously in a novel I just had to laugh. I'm amazed how prevalent it is tho, how lazy does an author have to be to use that!? what's next, "is that hardonium in your pocket or are you happy to see me?" 87.113.180.73 (talk) 02:01, 28 August 2010 (UTC)

Thanks, all - it's being used as an orbital tether, so has to be plenty hard - what I was worried about, I guess, was that the 1,8-Bis(hydridol) part of it might look so silly to a scientist, or even a lay person with some knowledge of chemistry, that they'd be distracted from the story. Adambrowne666 (talk) 05:49, 28 August 2010 (UTC)

Add a footnote that indicates that the compound is fictional. --Chemicalinterest (talk) 11:07, 28 August 2010 (UTC)

An orbital tether should be strong, not hard. The strongest material currently known is carbon nanotubes. Looie496 (talk) 17:16, 28 August 2010 (UTC)

I almost held this one for my special reserve, but my current draft features a world... not in the market for space elevators. So I should mention that if you read space elevator, you'll see that much of the problem meeting the specs involves a) a factor of two safety margin and b) that not every nanotube performs up to theoretical specifications. These two things can both be offset through better design in the future: specifically, if a "splint" travels up and down the tether, which allows the main cable to be broken apart at prefabricated joints, and a device precisely focuses high-frequency microwaves/IR down each and every nanotube at each of these joints, then each one can be tested for flaws. Possibly transitions induced by the electromagnetic radiation could actually repair small flaws in each tube; otherwise, a chip with microactuators could detach a single tube and feed through a fresh replacement. In this way conventional carbon nanotubes, perhaps doped up with a bit of boron and nitride, could do the job reliably. Wnt (talk) 18:31, 28 August 2010 (UTC)

Parallel connection of two sets of batteries

I want to keep a battery-powered LED flashlight on for a few more days. So I plan to add another set of batteries externally in parallel. Is it a good idea for the rechargeable batteries? Will it damage the batteries?

• Internal batteries: 4 * AAA NiMH (4 * 1.2 Vdc).
• External batteries: 4 * AA NiMH (4 * 1.2 Vdc).

I'll just leave the battery compartment open and let the wires from the external battery box touch the internal contacts. The whole thing will then be placed in a big waterproof plastic bag.

I know it's very bad to have mixed-type batteries serially connected because of internal resistance issues. I guess parallel connection of two sets of serially connected batteries shall not be a deadly sin. I just want to make sure it's not going to blow planet earth off its orbit. -- Toytoy (talk) 17:50, 27 August 2010 (UTC)

Parallel connections on rechargeables kills them. What happens is that one battery is slightly less charged than the other, so the first one tries to charge it, it overshoots, and then the second one charges the first, and the current swings back and forth over and over till both batteries are not just discharged, but also dead. This is a big problem for cars when you want to add a backup battery. For cars they usually add a manual cut-over switch. You may be able to solve this with some diodes. Ariel. (talk) 19:45, 27 August 2010 (UTC)

Do you have a citation for that? I'm having trouble buying the thermodynamics of that explanation. While connecting two batteries (of the same chemistry) with different charge levels will cause a current to flow as one battery charges the other, the current will decline as the two batteries approach the same potential, and stop as soon as they reach the same level of charge. I can't think of a mechanism by which the charging would 'overshoot'; it's not as if the wires are pipes full of momentum-laden flowing water.

By my reckoning, the reason one would put a manual cutover switch on an automobile's backup battery is not due to some weird cross-charging effect. Instead, it's so that when you leave your lights on in the car park (or are the victim of some other slow electrical leak), only one battery will go flat; you'll still be able to switch to the other fully-charged battery and be on your way. TenOfAllTrades(talk) 20:11, 27 August 2010 (UTC)

I also find it questionable. Parallel connection of NiMH batteries and various li-ion chemistries is quite common in various situations like for RC usage but also things like for DIY bicycle lights. There are also things like C and D adapters where you can use several AAA or AA in parallel for greater capacity but the price of AAA/AA. You should have relatively matched batteries (i.e. same type, capacity, age and charge state). However charging NiMH in parallel is can be a bad idea edit:particularly if you use a dV/dT method (see for example) edit:but actually any method is a bit risky (see ) so you do need some way to disamble them if you plan to charge them in that wayedit:for charging. (It's fine for li-ion types since they aren't charged like that.) Note for li-ion, parallel is even used for commercial laptop battery packs . Edit: also says the same thing Nil Einne (talk) 22:01, 27 August 2010 (UTC)

Battery voltage is not constant, it varies because it takes some time for the chemical reactions to equalize. For example when they sit for a little while the voltage goes up, and if you discharge them heavily it drops, then recovers later. Note: I've never experienced this personally, I'm just writing what I read about a while ago. Ariel. (talk) 22:03, 27 August 2010 (UTC)

That is true (to an extent), but the effects would not cause the 'see-saw' charging that you describe. Consider two batteries with different levels of charge, connected in parallel. The fully-charged battery will start to charge the battery with the lower charge. As a result, the apparent voltage across its terminals will decrease, while the voltage across the less-charged battery's terminals will increase. (Energetic reactants are being depleted from the first battery, and accumulated in the second.) The more-fully-charged battery will continue to charge the less-charged battery until the apparent voltage across each pair of terminals becomes equal. If you cut the cables at around this point in time, there can be a small amount of rebound in both batteries. The potential across the apparently-initially-full battery's terminals will rise slightly, as current is no longer being drawn off, and reactants are no longer being consumed. Similarly, the potential across the other battery's terminals will fall off a bit, as the components inside that battery equilibrate. If subsequently reconnected, a small amount of current will flow between the two batteries, in the same direction as before. The two batteries will eventually fully equilibrate, so that no current flows between them and they will maintain the same potential across their terminals even when separated. The important bit is that the potential across the first battery's terminals will never be lower than the potential across the second battery's terminals, and current will never be flowing back in the other direction. TenOfAllTrades(talk) 22:40, 27 August 2010 (UTC)

The first response above is completely wrong and should be deleted preferably by the poster. Cuddlyable3 (talk) 23:32, 27 August 2010 (UTC)

I agree. What actually happens with unequal cells in parallel is that as one cell's potential falls through discharge, the other provides more of the load current until the potentials are equal. There will be some recharging of the depleted cell once the load is removed, but no significant current swing. Ariel's point about potentials rising after the load is removed is certainly true. This is caused by recovery from polarisation, and it is possible that the cells will recover at different rates, but the cells will not discharge each other to a significant extent. There will be no significant harm done by connecting cells of the same composition in parallel, even if they have different capacities. It would be better if the cells could be separated once the load is removed, but this is not essential. I haven't set up a circuit to test my claims, but I'm convinced that any "swing" would be no more than a brief microamp causing negligible waste of charge. Can anyone find a reference to back this up? Dbfirs 19:13, 28 August 2010 (UTC)

If you want to use the internal battery and a similar external battery to keep a light on as long as possible, the optimal solution would be to use one set of batteries at a time, to avoid the more discharged cell from pulling current out of the more fully charged cell. Alternating use might be best, since a cell could recover a bit while resting. I expect considerable energy would be lost in the parallel connection versus the one set at a time use, provided that the drain is well within the current rating of the cells. Edison (talk) 20:28, 28 August 2010 (UTC)

I agree that alternating would be the optimum, but, if this is not convenient, there will be no significant energy loss in the parallel connection if both cells are fully charged at the start. Why would you expect considerable loss, Edison? I agree that there would be some loss if a charged cell were connected to a discharged cell. Dbfirs 21:13, 28 August 2010 (UTC)

3D jumping spider

Sorry for asking, but this jumping spider die in a small beaker in my lab and dried for an unknown period. It is 4mm in length and I broke a leg and the Pedipalp to get a better Scanning electron microscope 3D image of the Chelicerae. Is there a chance to get a rough estimate where to put it into the classification of jumping spiders?--Stone (talk) 21:08, 27 August 2010 (UTC)

I assume, from your userpage, that you found it in Germany? Smartse (talk) 21:48, 27 August 2010 (UTC)

Right. Right in the middle of Germany.--Stone (talk) 05:13, 28 August 2010 (UTC)

You can just run SEM on anything you want? DRosenbach 22:11, 27 August 2010 (UTC)

That is quite awesome! A while ago I took a similar picture of a bee's face with just a cheapy usb microscope, obviously the quality is much poorer. I reckon you should do some close ups of it's eyes and fangs. Vespine (talk) 01:04, 28 August 2010 (UTC)

The instrument is a very old (1960s I guess) and therefore there is no restriction for using it. So I will do some more pictures when I find some time. --Stone (talk) 05:13, 28 August 2010 (UTC)

Memory loss caused by Urinary Tract Infection - UTI

How does a urinary tract infection UTI cause memory loss - What is the actual biological/chemical mechanism?

I searched through quite a number of topics on Misplaced Pages, but the above information was not provided (searched Urinary Tract Infection, Memory, Memory Disorders, Amnesia). This information should be added to the appropriate articles. JSNC (talk) 21:14, 27 August 2010 (UTC)

Where did you get the idea that UTI causes memory loss? I see no reason why that would happen. Looie496 (talk) 21:51, 27 August 2010 (UTC)

I was just about to ask the same thing. It sounds pretty implausible and google scholar doesn't bring up anything obvious. Smartse (talk) 21:52, 27 August 2010 (UTC)

Don't you remember...it was on the news only last night! Maybe you've had one too many UTIs... DRosenbach 22:09, 27 August 2010 (UTC)

I never heard of this one, but it can be found easily enough: I'm seeing mention of delirium and TNF-alpha. Apparently the drug Ditropan for the urinary tract infection can cause memory loss. Good news is that it may readily be reversible. Just one more proof that nothing is impossible in biology! Wnt (talk) 22:36, 27 August 2010 (UTC)

August 28

Strength of piss

What is the thrust generated by an average penis ejecting an average amount of piss, as measured in newtons? —Preceding unsigned comment added by 81.44.97.243 (talk) 00:54, 28 August 2010

I only found normal values of uroflow for different genders and age groups, which are measured in mL/s. See uroflowmetry---Sluzzelin talk 01:05, 28 August 2010 (UTC)

So now that we have the amount of mass ejected per second (21.525 grams), we only need to know at what speed urine is usually excreted to complete the equation and find out how much thrust piss produces. —Preceding unsigned comment added by 81.44.97.243 (talk) 01:12, 28 August 2010 (UTC)

Surely it's the bladder that produces the force, not the penis... Physchim62 (talk) 01:38, 28 August 2010 (UTC)

You are absolutely correct Physchim62. Of course it is the muscles surrounding the bladder that generate the pressure in the urine in order to expel it. If that was not the case, how would women urinate? I suspect the OP really just wanted to post a question in which he got to publish the words penis and piss. I see a couple of smart Users deleted the question but our OP restored it both times, along with messages on the User talk pages of the deleters. I'm with the deleters. I think it is a crass question. Dolphin (t) 04:21, 28 August 2010 (UTC)

All that is needed for a woman to urinate is a relaxed sphincter: gravity will do the rest. The same goes for men, really. And I don't see anything wrong with the question, especially as it's given me the chance to dispel a myth held by yourself! --TammyMoet (talk) 08:19, 28 August 2010 (UTC)

Well, well, you're doing a great job of assuming good faith, aren't you Dolphin51? Couldn't my use of "penis" instead of "bladder" have been a genuine mistake? But well, keep screaming bloody murder every time you see a mildly low-registry word, if you wish...

As for those who were kind enough to reply, thank you. If as you say the major component driving piss flow is gravity, then that means an acceleration of 9.8 m. Therefore, after one second of flowing, piss is moving at 9.8 m/s. 0.021525 kg moving at 9.8 m/s equates to a thrust of 0.210945 newtons. Question solved.

... except that you need to include air resistance and the initial speed imparted by bladder pressure (which varies). Dbfirs 09:51, 28 August 2010 (UTC)

I'm not sure I agree, Tammy. Gravity is one component, sure, but I believe both genders are capable of regulating the rate of flow to at least some extent, too. By more than one mechanism, I would think. Anyway see Urination#Voluntary control.

To the OP, I would recommend the Thrust article. Wikiscient (talk) 11:36, 28 August 2010 (UTC)

The unfortunate individuals who aren't capable of regulating the flow by means of sphincter control suffer from incontinence (or retention if the sphincter is permanently closed). There are other factors, but if the sphincter is incapable of being closed, incontinence is inevitable. --TammyMoet (talk) 12:38, 28 August 2010 (UTC)

Ok. Assume the sphincter is completely open. Assuming an upright posture, gravity is helping void the bladder. Is it possible during this time to adjust the flow rate, without changing sphincter dilation, just by means of contracting or relaxing different abdominal muscle groups? Is there a significant gender difference in the control of that variable "thrust"? Wikiscient (talk) 12:54, 28 August 2010 (UTC)

One should also take into account that lots of men in time develop prostate cancer. This often causes problems with urination and effects flow. --VanBurenen (talk) 11:47, 28 August 2010 (UTC)

To calculate the initial speed, one could use the observation that younger males of the species have been known to engage in competitions to see who can reach the greatest height. (Perhaps between one and three feet would be typical? - some may have even stronger bladders?) A simple energy calculation (v = 2gh) gives the initial velocity. Initial velocity often tends towards zero with increasing age for males, as mentioned above, but to a lesser extent for females. Dbfirs 21:03, 28 August 2010 (UTC)

Surely we'd need to factor in the horizontal component of the velocity as well? Is there a standardised distance to the wall for such competitions? --81.158.2.129 (talk) 21:14, 28 August 2010 (UTC)

I don't know -- I never entered them! I assume that the distance is small so that air resistance is less and height is thus maximised, then the horizontal component of velocity would be small, but yes, my calculation would under-estimate the initial velocity. Dbfirs 22:19, 28 August 2010 (UTC)

about ICs

Why we use silicon chip only in ICs and not any other element —Preceding unsigned comment added by 182.156.95.31 (talk) 01:41, 28 August 2010 (UTC)

We don't only use silicon. List of semiconductor materials. Silicon is just the most commonly used one because it is, well, common. It is actually the 8th most common element in the universe and the 2nd most abundant element in the earth's crust. Vespine (talk) 02:03, 28 August 2010 (UTC)

It's also very easy to make ICs in silicon, and pretty hard in the other semiconductors. Silicon wafers are pretty hard to break or damage, which doesn't apply to the other materials. It's also easy to grow glass on the surface of silicon, which can't be done with the other materials. --Phil Holmes (talk) 10:40, 28 August 2010 (UTC)

A gas that clumps together in a gravity environment?

Is there some kind of high temperature gas that by its nature clumps together (even amid other gasses) in a gravity environment instead of spreading out? The gas would clump together in a gravity environment like water clumps together in a non-gravity environment? Are you ready for IPv6? (talk) 02:06, 28 August 2010 (UTC)

Water clumping is due to surface tension so since gasses do not have a surface, my guess is the answer is no. Another property of gas which makes me think this won't happen is that it will tend towards equilibrium in any container, whether there is gravity or not. Having said that, it depends on what you mean by "high temperature", once you hit plasma, the answer is probably different, but then it's no longer a gas. Vespine (talk) 02:26, 28 August 2010 (UTC)

I don't understand what you mean by water clumping together in a non-gravity environment -- water clumps together regardless of gravity. But that doesn't really matter, the answer is that anything that clumps together is a liquid or solid by definition, not a gas. Looie496 (talk) 03:41, 28 August 2010 (UTC)

Well, if you have enough gas that it can't escape its own gravity, then it will indeed "clump together". That's how stars form. Is that what you mean?

You might also be talking about plasma, as Vespine says; I disagree with him that that's "no longer a gas". Plasma is sometimes called "the fourth state of matter" but that's kind of bogus; plasmas are gases, just ones that are hot enough to be ionized, resulting in unusual behavior for gases as a result of electromagnetic forces. --Trovatore (talk) 03:47, 28 August 2010 (UTC)

If you fill (say) an aquarium tank with a heavy gas (Sulfur hexafluoride, for example) then it'll pretty much stay right there - held in place by gravity. One famous demo of this is to make a boat out of aluminium foil and float it on the surface of the gas. It behaves a lot like a liquid - if you make a hole in the bottom of the foil boat, it'll gradually fill with gas and sink! Do a search on YouTube for "sulphur hexafluoride boat" and you'll find a bunch of videos...(half of which are probably faked because it's YouTube)...but at least some of them are real! SteveBaker (talk) 04:30, 28 August 2010 (UTC)

Wow, I'd like to see that. SF6 sounds like really cool stuff. Too bad it's a greenhouse gas. --Trovatore (talk) 10:02, 28 August 2010 (UTC)

Are there any plasmas that will clump together like a some thick oil? Or what about a gas with a bunch of stuff dissolved in it like how water plus dirt makes sticky mud? Are you ready for IPv6? (talk) 05:30, 28 August 2010 (UTC)

What about gaseous bromine, for the gas, and ball lightning for the plasma? ~AH1 18:26, 28 August 2010 (UTC)

Bicycle physics

http://en.wikipedia.org/Bicycle_physics#Turning Please see Leaning section

The article gives the relationship between the lean angle and the other parameters as tanθ = m/(gr). I tried to work this out myself, and I was only successful if I assumed the normal force was acting parallel to the bike, as in an angle θ from the normal. But I thought the normal force was always perpendicular to the surface. Help? —Preceding unsigned comment added by 76.68.247.183 (talk) 02:15, 28 August 2010 (UTC)

The normal force N is the component that is perpendicular to the surface. When a vehicle is following a curved path there must be a centripetal force. In the case of a bicycle the centripetal force F_f is a force parallel to the surface. (In the diagram it is described as the Friction force.) The resultant force exerted on the bicycle by the surface is the vector sum of the normal force N plus the centripetal force F_f . This resultant force acts parallel to the bicycle, up through the center of mass of bicycle + cyclist (ie at an angle θ).

The equation is not tanθ = m/(gr) but v/(gr). Dolphin (t) 05:39, 28 August 2010 (UTC)

Sorry, I had meant v. But why would the resultant force act parallel to the bicycle? It seems to me that the bicycle could be at any angle, and the normal force and friction force would cancel gravity and the centrifugal force respectively. 76.68.247.183 (talk) 11:58, 28 August 2010 (UTC)

The resultant of normal force and friction must act through the combined centre of gravity because otherwise there would be a moment about the centre of gravity and this moment would rotate the bicycle. In practice, the rider corrects for any such rotation by adjusting the angle. It has been known for inexperienced pillion passengers on a motor cycle to lean the wrong way and thus overturn the motor cycle. Dbfirs 18:36, 28 August 2010 (UTC)

pituitarum

what is pituitarum? —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 03:25, 28 August 2010 (UTC)

From a scientific point of view, it's water. Salespeople might say otherwise. -- Scray (talk) 03:33, 28 August 2010 (UTC)

It's a homeopathic "treatment". Indeed - it's just water - and it doesn't work (unless you are trying to treat "thirst", for example!). Homeopathy is one of the great scams of our times - and it's hard to believe it's still legal. The manufacturers must be laughing all the way to the bank - they are charging $24 for 1 ounce of water! You can buy rather nice Evian spring water for $1.50 for 1.5 liters - which is about 3 cents an ounce...that means that the manufacturer of Pituitarum would be making an 80,000% profit if they didn't put the stuff in such nice little bottles! Unless of course they're using tap water - that's $3 for 1000 gallons - which is $0.00002 per ounce and would allow them to make a 100,000,000% profit if they sold the stuff in enough bulk! Not bad eh? So NEVER buy homeopathic products of any kind. See Homeopathy for details. SteveBaker (talk) 04:23, 28 August 2010 (UTC)

Never heard of "pituitarium", but I have some "homeopathic" remedies (cayenne pepper nasal spray) that makes your nose run a lot, but then stops it from running. It works; stopping my nose from running during a cold. --Chemicalinterest (talk) 11:12, 28 August 2010 (UTC)

That sounds more of a herbal remedy than the usual ridiculous dilutions of traditional homeopathy. Dbfirs 19:34, 28 August 2010 (UTC)

If you have a genuine homeopathic remedy, I highly doubt it works (other then as a placebo and/or hydrating you if necessary). A genuine homeopathic remedy is basically just water as others have said. This 'cayenne pepper nasal spray' doesn't sound like it's really a homeopathic remedy. The term is sometimes used loosely to mean any form of Alternative medicine at least a Westernised one but that isn't the traditional meaning (which our article uses). A real homeopathic remedy involves sufficient serial dilution that what you end up with is water. If your 'cayenne pepper nasal spray' actually smells like something other then water, then it clearly is not a homeopathy remedy, even if it may call it self one Nil Einne (talk) 12:16, 28 August 2010 (UTC)

Homeopathy works. Just look at how many people piss piss after they drink water, and no wonder: all of the world's water has passed through piss. 67.243.7.245 (talk) 16:03, 28 August 2010 (UTC)

The central secret of homeopathy is that merchants can get away with labeling something with the name of some herb and a concentration like "10X" or "50X". And reasonable people assume, that's ten times some standard concentration. But that's not what it means! It is a special secret homeopathy notation that means that some fairly standard old USP drug has been diluted 1 to 10 for 10 times, or for 50 times, etc. Leaving no non-water molecule present. There's all kinds of post hoc explanation for this, but obviously it's the money.

Question: has anyone ever actually checked that they really start with the indicated drug solution? I bet they fill those things up straight from the tap. Wnt (talk) 17:59, 28 August 2010 (UTC)

Meaning of 'Red" in Red-Al

What is the meaning of "Red" in Red-Al? Does it mean the color or Red-Al? or it has other meaning ?

Thanks--Wolfch (talk) 04:49, 28 August 2010 (UTC)

Reduction or reductive.--Stone (talk) 05:16, 28 August 2010 (UTC)

Entropy

Why the cyclic integral of dQ/T for a cyclic reversible process is zero?? Does Entropy remain constant in an irreversible adiabatic process?? —Preceding unsigned comment added by 115.109.194.75 (talk) 13:25, 28 August 2010 (UTC)

What is the solubility of polystyrene in acetone?

Or, in other words, given a certain amount of acetone, say 100g, what's the maximum amount of polystyrene that will dissolve in it? 76.27.175.80 (talk) 15:23, 28 August 2010 (UTC)

This might be slightly tough to answer, as it will depend to at least some extent on temperature but also the size of the polystyrene chains. (Here is a paper for 60-ish years ago about how the solubility of polystyrene varies with molecular weight.) I don't know how standardised the molecular weight in commercially-available polystyrene is. It does, however, sound like the sort of experiment one could easily do at home (with appropriate safety precautions, of course). --81.158.2.129 (talk) 20:24, 28 August 2010 (UTC)

Herbal remedies

Why are herbal remedies considered alternative medicine? Many herbs contain chemicals with various beneficial effects. --70.134.48.188 (talk) 15:30, 28 August 2010 (UTC)

I presume this is coming from my answer to the above question? If so did you read the linked article?

In Western culture, alternative "medicine" is any healing practice "that does not fall within the realm of conventional medicine", or "that which has not been shown consistently to be effective." It is often opposed to evidence based medicine and encompasses therapies with an historical or cultural, rather than a scientific, basis.

Later it says

Jurisdictions where alternative medical practices are sufficiently widespread may license and regulate them. The claims made by alternative medicine practitioners are generally not accepted by the medical community because evidence-based assessment of safety and efficacy is either not available or has not been performed for these practices. If scientific investigation establishes the safety and effectiveness of an alternative medical practice, it then becomes mainstream medicine and is no longer "alternative", and may therefore become widely adopted by conventional practitioners.

I had planned to explain further but actually this seems clear enough to me.

But to summarise, most herbal remedies (and anything else that's alternative medicine) don't have sufficient evidence-based assessments of their efficacy and safety that is required by regulating agencies throughout the world, and in fact supporters of such remedies have generally strong opposed requiring such products to be regulated in the same way. Therefore they are alternative medicine.

If a herbal remedy does meet the same standards expected of normal medicine, then it isn't considered alternative medicine. However demonstrating the efficacy is not cheap or easy so it's rarely done (and often when the tests are done they are inconclusive or show now evidence). Also if you are going to go through that process it often makes sense to isolate the active compound and patent it if you can. That enables you to more easily control the variables and deliver higher levels. (Some alternative medicine practices are inherently opposed to the norms required too.)

To use an example, I could say 'cat fur is a great treatment for infertility'. This is something I just made up so is almost definitely nonsense. Some people may very well believe that cat fur has various beneficial effects, but without evidence it ain't science.

A different more real example would be vitamins and minerals. If you have a poor nightvision and a doctor determines you probably aren't getting enough vitamin A, they may very well proscribe vitamin A tablets and recommend a change in diet. This wouldn't be considered alternative medicine. Megavitamin therapy is however.

Nil Einne (talk) 15:58, 28 August 2010 (UTC)

One more thing worth mentioning perhaps.. there have been many cases in which herbal remedies have been studied, found effective, and the active ingredient identify and isolated. See History of aspirin for example. Once this has happened generally the herbal version falls out of usage in favor of the more consistent and controlled preparations. Lots of new-ager types will claim that herbals are "natural" and therefore not "drugs" and thus are somehow better and safer.. but this is nonsense. Plants can vary in potency, and will contain lots of ingredients other than the ones you want for medicine. When we manufacture a drug, we can make it contain just what we want, at a known dosage level. It's possible of course that some herbal remedies are out there which are effective and whose active ingredients have not yet been identified. But it's more likely that the ones that remain herbal remedies are there because they are not effective and have no useful active ingredients. Friday (talk) 16:23, 28 August 2010 (UTC)

However, it should be noted that natural willow bark salicylates, which are conjugated to sugars rather than just an acetyl group, have been shown to be more potent than aspirin, and do not cause gastrointestinal lesions and bleeding, a very widespread and potentially life-threatening side effect of long term aspirin usage. (See PMID 12244878, ) Yes, it's true - the stuff they sold in Ur 5000 years ago is better than the controlled chemical preparation that the FDA has certified for you!

So while your statement that regulated remedies are tested, while herbal remedies are not, might be true, it might also be true that medical regulation is a racket which stands between people with common complaints and ancient, well-known remedies to alleviate them, permitting them to pass by only if they hand over a large portion of their total wealth. Wnt (talk) 18:14, 28 August 2010 (UTC)

In nutrition, there is agreement that fresh fruit and vegetables are preferred over some combination of artificial vitamins and fiber. If it's all that "other stuff" (much of it unknown) that makes fresh produce more beneficial than isolated active ingredients, then might the situation be analogous for herbal remedies?--82.113.106.28 (talk) 16:35, 28 August 2010 (UTC)

When I trained as an aromatherapist, I was told that the synthetic lavender oil had none of the therapeutic properties of lavender oil obtained from nature. I don't have a reference for this (I no longer have access to the relevant research library) but have found this: adulterated oils and their effects. --TammyMoet (talk) 17:09, 28 August 2010 (UTC)

Well, aromatherapy is generally based on tradition rather than evidence, is it not? So I wouldn't be surprised to hear that many of them believe that the natural version has a magical "essence" that is lacking in a synthetic version- this is vitalism which is a common view in alternative medical practices. And yes, with food, most people will say that you're better off getting your vitamins from real food rather than vitamin supplements. This is, to some extent, to encourage people to eat healthy foods rather than eating crap and trying to make up for it with vitamin pills. Friday (talk) 18:01, 28 August 2010 (UTC)

Yes I accept that, but these days there is a growing body of research into aromatherapy (as well as other alternative/complementary medicines) which has been conducted "according to the rituals of the Church of Science" (as I like to call scientific research orthodoxy). I used to have access to the major UK repository of this research, but as I'm no longer a student I don't. It's not really acceptable to dismiss CAM as being not research based these days because of the research which is being conducted by, among others, Dr Peter Mackerras at the Christie Hospital, Manchester. The studies are, of necessity, small - who can match the research budget of GlaxoSmithKline, for example? but nevertheless it exists. --TammyMoet (talk) 18:36, 28 August 2010 (UTC)

Take a look at homeopathy, naturopathy, traditional Chinese medicine, orthomolecular medicine, culture-bound syndrome and acupuncture. ~AH1 18:22, 28 August 2010 (UTC)

Wind on mars

Is the martian atmosphere sufficiently dense/energetic to move martian dust around? If so how long will it take for the tracks of spirit and opportunity to be obliterated? -- SGBailey (talk) 16:29, 28 August 2010 (UTC)

Spirit rover#Dust devils...small dust storms have cleaned the panels from Spirit. So yes, there's wind. Since there's enough to move dust around like that, I wouldn't think the tracks would last long at all...but I don't know. Vimescarrot (talk) 17:28, 28 August 2010 (UTC)

Also Climate of Mars#Wind. Vimescarrot (talk) 17:29, 28 August 2010 (UTC)

See Mars dust. Strong dust storms occur regularly on Mars with enough intensity to envelope the entire planet. ~AH1 18:18, 28 August 2010 (UTC)

There is a panoramic image of one of the rovers taken over a whole winter. The tracks from roving in that area before the winter started are 100% visible and look very undisturbed. I talked to a Scientist Walter Goetz an he told me that the 9mbar only allow very fine dust particles to be carried around by the wind. The small cm high dunes would take year to create and the tracks would take decades or centuries to vanish. If there is a strong dust devil this might change, but most of the landscape on mars is changed very slowly. The dark tracks of the rovers can be seen from MRO for a very long time --Stone (talk) 20:32, 28 August 2010 (UTC)

The image I was thinking of is File:McMurdo panorama.jpg --Stone (talk) 20:37, 28 August 2010 (UTC)

sneeze

How powerful is a human sneeze. user--86.41.133.57 (talk) 17:28, 28 August 2010 (UTC)

According to sneeze, "Conservative estimates place the speed of release at around 100mph. However, the data collected from the 147th episode of Mythbusters titled 'Flu Fiction', concluded that the speed is closer to 35-40 mph, and launching from 15-20 feet." ~AH1 18:16, 28 August 2010 (UTC)

That was a good experimental test of velocity and range. "How powerful" seems to need an answer in watts or other units of power, though an answer stating the total energy would also be relevant. Edison (talk) 20:19, 28 August 2010 (UTC)

sequence, chain, scheme

Just a quick question, do the phrases "decay sequence", "decay chain" and "decay scheme" all mean the same thing (when referring to radioactive decay). Thanks. Differentially (talk) 17:43, 28 August 2010 (UTC)

They're all related, but all refer to slightly different ideas. A decay chain is the set of different nuclides that are formed on the way to stability. Personally, I would say "decay sequence" was a synonym (and it's certainly used as such on Misplaced Pages) but looking around online some sources (e.g. here) use it to specifically refer to a plot of a decay chain on the N-Z diagram to show the changes going on. OTOH, a decay scheme is a more detailed look at an individual step in terms of the energetics and particular products involved. --81.158.2.129 (talk) 20:17, 28 August 2010 (UTC)

Synthetic cannabis

This a general request for further information about synthetic cannabis.

• How do its experiential effects in humans compare to those of (natural) cannabis?
• Has there been any further work done recently on its psychopharmacological mechanism of action?
• Have any long-term physiological/psychological consequences of its use been determined?
• Does anyone have any good recipes to share as to a really good mix of synthetic cannabinoidal agents?

(Note that this substance is still legal (and readily available) in much of North America and Australasia (but not in the UK). Thanks, Wikiscient (talk) 18:15, 28 August 2010 (UTC)

I think the quotes from Huffman are rather illuminative. The problem is that if you speak of psychoactive effects, they are so subjective that it would be next to impossible to define what is "good" or "bad" or even "the same". Perhaps with some fMRI...? But I doubt it's being done, because who's going to fund the study? As for other health effects, it is clear that natural cannabis contains highly useful and non-psychoactive compounds like cannabidiol, which alleviates nausea without creating a "high" - so conversely there should be healthy effects that these synthetic cannabinoids cannot duplicate. (Note that from the days of Marinol cannabis psychoactives have always been more legal than cannabis therapeutics, and cannabidiol remains strictly and severely illegal. However, ginger has not yet been banned, and may help with some forms of nausea) Wnt (talk) 18:50, 28 August 2010 (UTC)

. Wikiscient (talk) 19:23, 28 August 2010 (UTC)

The psychoactive properties of cannabis may not contribute to its medical use, but oddly, its medical use might contribute to its psychoactive properties. As Huffman said, "It's like playing Russian roulette. You don't know what it's going to do to you... You're a potential winner of a Darwin award." The same article says that Scalzo said "the symptoms, such as fast heart beat, dangerously elevated blood pressure, pale skin and vomiting suggest that K2 is affecting the cardiovascular system of users." Now bear in mind that cannabidiol and other components greatly suppress nausea, and that cannabigerol and cannabidiol lower blood pressure. Thus, by separating the high from the cannabis, you may take a known experience and turned it into an exercise in being terrified and dizzy-sick, if not worse. Wnt (talk) 20:32, 28 August 2010 (UTC)

Dragonfly Species Identification

This was in my backyard. It is in southern California, driving distance to coast the coast.

It has brownish-wings and bright red abdomen.

Even a genus or family would been appreciated.

• From top

--Mathboy48 (talk) 20:23, 28 August 2010 (UTC)

I'm going to guess either a Flame Skimmer (Libellula saturata) or a Sympetrum species, perhaps S. illotum, both of which are which are found throughout California (though the latter tend to hold their wings angled downward when resting). Cf. this image of the former. There are a number of other possibilities, though, and precise identification depends on characteristics (such as size) that aren't really visible in the photo. You may find the field key here helpful. Deor (talk) 21:52, 28 August 2010 (UTC)

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