Wikipedia:Reference desk/Archives/Science/2011 January 30

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January 30

My Honda Accord will be 10 years old this year. Why no rust?

Some junked antique cars are coated with rust, and I've read that they've rusted rather quick.

Yet my 2001-model has almost 130,000 miles so how does it remain rust-free anyhow? --70.179.181.251 (talk) 00:12, 30 January 2011 (UTC)

There are lots of factors that cause different amounts of rusting. If you maintained your car very well, and didn't drive it on a lot of salted roads, I would not expect it to rust. All of our cars have been far older than that when we got rid of them, and other than a tiny spot, I can't remember any rust on any of them. Of course, it could be rusting in places that you don't see, but even that's not a guarantee. Basically: it depends on a lot of different things. I cannot tell you why your car specifically is not rusting, but I can surmise why a car might not rust after ten years. Falconus^{p t c} 03:14, 30 January 2011 (UTC)

At least in Germany, it's now standard for most new cars to have a fully zinc galvanized body, which makes rust a very rare occurrence. Toyota started the wide-spread use of galvanized steel in Europe in 1992, and seems to use it more or less universally since 2000. Car-makers now have the technology to nearly completely eliminate rust as a problem, although not all use it to the same degree (arguably, there is no reason for outstanding longevity if cars are retired for obsolescence reasons after 10 years anyways). --Stephan Schulz (talk) 09:19, 30 January 2011 (UTC)

Sorry, my mind misread Honda for Toyota. I don't know when exactly which Honda models started using galvanized steel, but from what I could find online it should be in a similar time frame.--Stephan Schulz (talk) 12:05, 30 January 2011 (UTC)

As above - modern cars rustproofing is a lot better than before. If you're driving in a dry climate without lots of rain, snow or ice the car's bodyshell will not degrade very much. Exxolon (talk) 16:38, 30 January 2011 (UTC)

Short answer: It's a Honda. :P Roger (talk) 17:38, 30 January 2011 (UTC)

How do I customize GPS navigation voices?

I think the voices that vehicles give through their embedded GPS navigation systems should reflect their ages and nationalities. At least the voices of the vehicles I plan to drive, anyway. Moreover, I'd also like some kind of subroutine that will "age"/deepen the voice of the navigation system as the vehicle ages.

For example, if I buy a used 2005 Volvo XC90 in 2013, how do I get the navigation program to voice out the directions sounding like a Swedish boy?

I think if I drive a Hyundai, the GPS voice should have a Korean accent. If I drive a Fiat, an Italian accent, etc. Moreover, their voices should reflect the date of the car's manufacture. (I won't have to worry too much about how silly they'd sound because I don't plan to buy vehicles newer than 5 years old anyway. It saves a bucketload of $$$ buying used.) --70.179.181.251 (talk) 00:12, 30 January 2011 (UTC)

I think most commercial GPS systems do not synthesize their voice phonemically; they simply play back a series of sampled words. So you would need to (1) pay a voice actor with your desired voice and accent to record a complete vocabulary for the navigation system, (2) rent a voice recording studio for him/her to do it in, (3) pay the manufacturer of the GPS system to help you get the new vocabulary into the box's firmware, as if it was a new language localization. The latter is not an off-the-shelf service; you could easily be looking at $10,000 or more here, and expect to pay in advance. Repeat everything whenever you think the voice ought to change due to the car aging.

Oh, and the GPS manufacturer may not even want to touch this unless you promise that they won't get sued if you let somebody borrow your car and they misunderstand the GPS directions and end up in a river and drown, and they may want you to back this promise with a bank guarantee or a fully paid up indemnity insurance policy, which isn't cheap either, and then you'll also want to pay a lawyer to go over the promise before you sign it, to make sure you're not accidentally signing away your firstborn.

It may be cheaper if you start out with an open-source navigation system running on off-the-shelf laptop or smartphone hardware, though in that case you'd need to hire a freelancer or consultant to do the heavy lifting (you can legally do it yourself, but if you had the skills to do so you wouldn't have to ask here), and that would still set you back at least several thousand dollars in addition to the actor's fee, and you'd risk getting a less stable and feature-rich system than a commercial GPS solution. –Henning Makholm (talk) 02:29, 30 January 2011 (UTC)

Henning is right about commercial sat nav systems, but there is an alternative: the free navigation app from Google, available on Android smartphones. It uses the Google text-to-speech (TTS) engine, which is customisable in principle since it's open source. How you would do it in practice, though, I have no idea. Also, it's currently only available in the USA and the UK. The British one sounds as you would expect the Bride of Frankenstein to sound. It tries to synthesise place names phonetically, often getting them wrong, but you can usually work out what it's trying to say. --Heron (talk)

Standalone GPS systems are easy to customise as long as you have voice samples in a compatible format and the master list that tells the system there's a voice there and which sample to play for each situation. If you could access the memory of an integrated system it should be possible to do the same. Exxolon (talk) 16:36, 30 January 2011 (UTC)

Vocal synthesizers, not voice actors.

Problem is, I'm not looking for actors' voice samples. I'm looking for vocal synthesis Aren't there vocal synthesizing programs that enable me to change any vocal recording to that of a desired age? Why can't I just convert the existing recordings to those instead?

(And if I do get a vocal synthesizer, how do I also change the accent to that of a desired country's?) --70.179.181.251 (talk) 17:08, 30 January 2011 (UTC)

This might be more of a question for the computer desk. Most SatNav vendors have a wide range of voices that can be downloaded from their website, some free, some purchased. The files are easy to install, simply copied to the SatNav flash drive. However, the data is not in a publicly published standard so it will not usually be possible to create your own without collaboration with the manufacturer. As Heron said, many devices use sampled voices rather than synthesis so there would be no way of programming in a variant synthesiser, there is just no facility. The best you could do would be to access the analogue audio going to the speaker (which will probably involve taking your satnav apart) and feeding it through a voice disguiser, suitably adjusted for the effect you are looking for. SpinningSpark 19:38, 30 January 2011 (UTC)

GPS satnav system are just not set up for this. If you connect one to your PC and browse it, you'll find a folder for the voices. Each subfolder contains all the samples needed to construct all the sentences ever needed and a file telling the satnav which sample to play when it needs to make that particular part of a sentence. Looking back at your original post it looks like you want the GPS to reflect the cars "personality" for want of a better term - an integrated SatNav with a voice that's appropiate for the car make, model and age - no manufacturer will bother doing this - it's a lot of expensive work for a demand that's just not there. It would be just about possible to do this manually assuming you could find or record samples in the relevant accent, timbre, elocution etc and access the satnav memory - you could then manually set the voice to match the car. However you'd have to do this manually for each make/model you wanted to do - there's no way to do it automatically. You'd also have to periodically replace the samples manually if you wanted to reflect the age of the car - there's no way for the satnav to switch samples based on the age of the car. This really isn't going anywhere. Exxolon (talk) 01:04, 31 January 2011 (UTC)

My sister's TomTom satnav has a range of different voices, accents and languages - I believe the feature was built in when she bought it. She prefers the Irish accent of "Sean" over the "posh English lady" :-) TomTom#Upgraded Voices suggests some of their products support the purchase(?) of celebrity voices. Astronaut (talk) 17:11, 31 January 2011 (UTC)

What's at the edge of a piece of diamond or graphite?

Or other lattice compounds, for that matter. Unlike molecular compounds, the atoms on the edge would have unpaired electrons, so what do they do? Do they just bond with random hydrogen or oxygen atoms from the air? --75.15.161.185 (talk) 03:17, 30 January 2011 (UTC)

Yes --Plasmic Physics (talk) 03:33, 30 January 2011 (UTC)

See in particular material properties of diamond, which contains some discussion of which terminators they typically end up with. Apparently we have nothing similar for graphite (I wonder whether it would be an acute problem there -- because the orbitals are hybridized throughout the graphite layer, the burden of lacking an electron could be shared among many more atoms than in a small radical. On the other hand, it appears that a phenyl anion is not considered aromatic, so perhaps the edge atoms are not allowed to just borrow their missing electron). –Henning Makholm (talk) 04:23, 30 January 2011 (UTC)

What if it's formed in a vacuum by vapor deposition? --75.15.161.185 (talk) 13:24, 30 January 2011 (UTC)

Then it would appear that the graphite has no choice but to grow with unpaired electrons at the edges, wouldn't it? As far as I can search, the most abundant molecules in carbon vapor are things like :C=C: and :C=C=C: which have more unpaired electrons than they have atoms, so it would still be a net win for them to join a growing graphite sheet, even if the sheet does not terminate nicely. –Henning Makholm (talk) 14:44, 30 January 2011 (UTC)

fruit

If a fruit falls from a tree and no animal eats it, will the fruit aid in the seed in growing? —Preceding unsigned comment added by 92.3.157.72 (talk) 03:35, 30 January 2011 (UTC)

If the fruit is not eaten by an animal, it's likely to rot before the growth season starts anyway. And even if it miraculously avoids rotting, the seedling would have to absorb the sugars from the fruit through its root, and it's far from clear that it would be up to that task -- the root epidermis would have to express specialized membrane transport proteins for this, and likely has no evolutionary reason to think trying that might be a good idea. It's even possible that the osmotic pressure of the sugar would make it difficult for the seedling to absorb enough water to grow. –Henning Makholm (talk) 04:55, 30 January 2011 (UTC)

Wait, surely the fruit rotting is a good thing, as now the seeds are sitting in a small amount of compost? I don't think any theory of fruits and seeds proposes that the seeds make use of the unrotted fruit. I'm sure many plants rely on animals eating the fruit to disperse the seeds, but that seems far from the only purpose of fruit in all non-cultivated plants: there are fruits with protective systems to prevent them being eaten, for example. And some apples, for instance, do rot where they sit without being eaten, and then the apple seed grows in the apple-enriched earth: there doesn't need to be only one benefit to something. 86.164.58.119 (talk) 10:33, 30 January 2011 (UTC)

This is a common misconception; the main purpose of fruits is not to provision seeds. Generally speaking, the purpose fruit serves a plant is to disperse the seeds via animals. This is a classic mutualistic interaction, because it benefits both the plant and the animal. SemanticMantis (talk) 05:33, 30 January 2011 (UTC)

And where fruits contain poison normally the poison is only present until the fruit is ripe or it is only in the nut or it is poisonous to some mammals rather than birds for instance so the seed gets widely dispersed. Dmcq (talk) 11:01, 30 January 2011 (UTC)

What is the point of the rough almost armoured coat on a lychee? This coat or rind seems "designed" to prevent animals from eating it. Thanks 92.29.125.152 (talk) 14:09, 30 January 2011 (UTC)

Plants often 'target' a certain animal to disperse their fruit. In the case of the lychee, the shell may keep out insects or mice, but allow a bird to eat the fruit and carry it farther. SemanticMantis (talk) 14:17, 30 January 2011 (UTC)

Dmcq mentioned something similar (before the OP's question) and there are also chillis and durians as other examples of targeting the right dispersal agent/animal. Nil Einne (talk) 15:14, 30 January 2011 (UTC)

Durians 'target' a handful of primates annually, resulting in several fatalities. -- 110.49.193.138 (talk) 17:22, 31 January 2011 (UTC)

the temperature of crab nebula

i had read any subject in scientific american that the temperature of nebula of such crab is 10⁴ degrees centigrade . i want to know if that is so or i have forgotten. --78.38.28.3 (talk) 06:22, 30 January 2011 (UTC)a.mohammadzade

I've fixed the formatting so that the question is more easily readable. Mitch Ames (talk) 06:27, 30 January 2011 (UTC)

According to our Crab Nebula article:

In visible light, the Crab Nebula consists of a broadly oval-shaped mass of filaments ... The filaments' temperatures are typically between 11,000 and 18,000 K ...

10⁴ degrees Centigrade is about 10,000 Kelvin, so the visible part of the nebula is about 10⁴ °C. Mitch Ames (talk) 06:35, 30 January 2011 (UTC)

ok thanks alot .then for recent observation the crab nebula is accelerating particles . is there any nucleic reaction in such clouds?--A.mohammadzade (talk) 06:57, 30 January 2011 (UTC) — Preceding unsigned comment added by A.mohammadzade (talk • contribs) 06:49, 30 January 2011 (UTC)Template:Unsigned -->

Note that "temperature" is fairly misleading in this setting. The crab nebula is a high-quality vaccum by our standards. So while the average energy of molecules in the nebula is high (that defines "temperature"), the energy density is extremely low. You could sit inside the nebula in a space suit forever, and still loose more energy from your thermal radiation at ~300K than you would take in from the rare interaction with one of the "hot" particles. The nebula is a recent supernova remnant. Supernovae often generate a lot of (in absolute terms) very heavy radioactive elements. So I'm fairly certain that there still is a measurable amount of nuclear fission going on in the nebula. I don't think there is an appreciable amount of fusion, though. --Stephan Schulz (talk) 09:27, 30 January 2011 (UTC)

Tidal Locking Formula

Dear Wikipedia

I emailed Dr. Burns at Cornell University (e-mail address removed). He said that he had a quick look for formula 2 [which has 10 to the 10 years on the end of it] and it is not in the book cited on the wiki page. http://en.wikipedia.org/wiki/Tidal_locking#Timescale

Would Dr. Peale know? (e-mail address removed)

I have removed e-mail addresses in the above, as per the policy at the top of this page. Red Act (talk) 09:35, 30 January 2011 (UTC)

The formula you seem to be referring to is not cited to a book at all. Which book is it missing from? Do you contend that the formula is wrong? –Henning Makholm (talk) 11:34, 30 January 2011 (UTC)

Can anyone provide clear, simple answers to these Mandelbrot Set questions needed

1. I’ve heard that the Set is connected I gather this means it has no islands. Does that mean you could go from any point on it to any other point without lifting your pencil? But could you do it without crossing any other line?

2. I see great electric lightning type tendrils coming from the main body. Are these lines or do they have have some kind of width? With the tendrils, I have seen images where they extend many times further than the diameter of the main body. How far is the longest one/

3. Also on tendrils coming from the main body, I notice that they seem to be more violent and extensive at the poles of the three main bodies, and that more sub MD sets are clustered there. Is this true, or do I just imagine that there are areas more conducive for such activity?

4. On the tendrils, sometimes a sub-MD appears. How does this happen? Why does a tendril go on normally and then suddenly explode into a full MD. Is there some value in the code which, when it is encountered, explodes it into a whole new set?

5. It says in the article that the MD is self-similar, but unlike Koch’s snowflake and others, you can’t make a priori predictions as to what will be happening down levels deeper. I’m told that this means that the volume enclosed by the set can’t be calculated except within limits. Is this true?

6.There seems to be no shape or line in this set which looks like anything in Nature, expect superficially. There are no circles or lines. I noticed in images that the lance of the MD seems to have something like a straight line, or gradually curved one, and that the fractal activity there appears less complex. Are there areas of the Set where complexity is reduced compared to other areas? Can this complexity scale be measured? Myles325a (talk) 11:57, 30 January 2011 (UTC)

1: Yes, when we say it is connected, it means you could (in principle) draw a line from one point in the set to any other point in the set, without leaving the set or lifting your pencil. SemanticMantis (talk) 14:55, 30 January 2011 (UTC)

5: Basically, yes. Note that the Mandelbrot set is not self-similar in the same strong sense that the Koch curve is. There is at the moment no exact area known for the Mandelbrot set, but we can (in principle) calculate it as precisely as we choose. Related is the idea of the Coastline problem, which is often paraphrased as "The length you get when measuring a coastline depends on the length of your measuring stick". SemanticMantis (talk) 16:18, 30 January 2011 (UTC)

6: It is interesting you say no shapes that look like 'nature', and then mention circles and lines. It is true there are no perfect circles or lines in the (boundary of) the Mandelbrot set, but there are also very few circles or lines in nature (i.e. the physical world). In fact, many sources mention that things like clouds, mountains, or islands are better described by fractal geometry than Euclidean. SemanticMantis (talk) 14:14, 30 January 2011 (UTC)

4: There is no why. The set is what it is. There is no secret input value hidden in the code. In fact, the code is incredibly simple. 71.101.41.73 (talk) 16:34, 30 January 2011 (UTC)

2: These filaments do have width, a program such as fractint will let you zoom in to see more detail. Also note that all the pretty colors are outside of the set, and colored by 'escape speed'. For the questions you are asking, you want to focus on the second, black-and-white picture in our mandelbrot set article. SemanticMantis (talk) 21:11, 31 January 2011 (UTC)

Delivery

during the delivery of a child the child does not get harrased or injured while passing through the pelvic girdle? — Preceding unsigned comment added by Joshuki (talk • contribs) 12:15, 30 January 2011 (UTC)

See Birth trauma (physical) for some types of physical injury that the child can sustain during delivery. As for harassment, I think the risk is low. Staecker (talk) 13:56, 30 January 2011 (UTC)

What do nebulae look like in visible light?

What would a nebula look like if you were inside it on a spaceship? --75.15.161.185 (talk) 13:26, 30 January 2011 (UTC)

It depends on the nebula. For interstellar clouds, in most cases, it would be invisible. Matter is very diffuse in these nebulae. The Great Andromeda Nebula would presumably look a lot like the Milky Way from the inside. --Stephan Schulz (talk) 13:35, 30 January 2011 (UTC)

Would it ever look like the dense, glowing fog/clouds used in TV shows like Star Trek? --75.15.161.185 (talk) 15:11, 30 January 2011 (UTC)

Only if you use a positronic scan with reversed polarity. --Stephan Schulz (talk) 15:43, 30 January 2011 (UTC)

Make it so, Mr. Broccoli. --Anonymous, 03:52, January 31, 2011.

This wasn't really answered satisfactorily, and I can't do it properly either, but consider that the Crab Nebula has absolute magnitude of −3.1 ± 0.5, compared to 4.83 for the Sun - in other words, it is much, much brighter from a given distance. Our close neighbor Sirius has magnitude 1.42, and it's the brightest, flashiest star in the sky - though admittedly, all that brightness is in one dot rather than in a large cloud. I think something like the Crab Nebula should be spectacularly visible from neighboring stars, but I wish an astronomical expert would chime in with details. Wnt (talk) 02:28, 2 February 2011 (UTC)

This does need a better answer, but a rough calculation tells me it will remain invisible to unassisted human vision at any distance. From 6500 light years away it subtends an area of about 5 by 7 arc minutes, that is about 4 percent of the area subtended by the Moon. Move 5 times closer to 1125 light years away and it will appear as large as the Moon does from Earth, but its apparent magnitude has only risen to about 5. This would be the same as a very short-sighted person such as myself trying to see a magnitude 5 star without glasses. I have difficulty even seeing magnitude 2 stars without glasses! -84user (talk) 11:51, 2 February 2011 (UTC)

Actually I was thinking of being just a few light-years away, like Sirius, and the OP was asking about how it looked from inside. While the increase in brightness is initially cancelled out by the increase in size as one gets closer to an object, I don't think this applies when it fills a large portion of the sky. Wnt (talk) 21:33, 3 February 2011 (UTC)

cell sonicator

is there any other cell distruption method, other than sonicator ? —Preceding unsigned comment added by 115.242.140.78 (talk) 15:24, 30 January 2011 (UTC)

Yes, there are a number of different options. The optimal method will depend a lot on your ultimate goal and what you want to do with your cell lysate. As it turns out, we have a very interesting article entitled cell disruption that would be a good place to start. --- Medical geneticist (talk) 15:38, 30 January 2011 (UTC)

I'm surprised that this article doesn't mention old standbys like a Dounce homogenizer or freezing in liquid nitrogen and grinding in a mortar and pestle. (See e.g. [1] and [2] for description) Wnt (talk) 21:42, 3 February 2011 (UTC)

A scientific test to determine if Blacks are dumber than Whites

If we wanted to design an thorough scientific experiment (and ignoring all ethical considerations) to determine if Blacks are dumber than Whites for purely GENETIC reasons alone, how would we design the experiment? I came up with the following experiment, please tell me if this is a good experiment (ignoring ethical considerations) with proper controls.

The sample size of each group is unclear to me at this point. Suggestions on minimum sample size would be helpful.

1 group of newborn Blacks with at least 90% of their DNA can be traced to Sub Saharan Africa. Divided into two subgroups, one half is intact, the other half has their skin bleached. Half of the intact newborns, and half of the bleached newborns are placed into adoptive parents that live in upper class society. The race of all the parents should be white. The other half of intact and bleached newborns should be placed into adoptive parents that live in lower class society in the inner city. The race of all the parents should be black.

1 group of newborn Whites with at least 90% of their DNA can be traced to Europe. Divided into two subgroups, one half is intact, the other half has their skin darkened (not sure how this can be accomplished, but lets assume that it can be). Half of the intact newborns, and half of the darkened newborns are placed into adoptive parents that live in upper class society in the suburbs. The race of all the parents should be white. The other half of intact and darkened newborns should be placed into adoptive parents that live in lower class society in the inner city. The race of all the parents should be black.

As they all grow up, they should be given IQ tests at different time intervals, and their academic performance should be measured. This experiment would last for several decades.

The bleached and darkened newborns are there as controls. If the bleached Black newborns performed as well as intact Whites in their respective socio-economic levels, it would prove that intelligence is determined from purely external factors, and not determined by genetics.

How is my experiment? Suggestions? Are there any unnecessary groups? What should be changed? Etc ScienceApe (talk) 16:53, 30 January 2011 (UTC)

Well (gritting my teeth and trying to ignore the offensive wording of parts of the question), to have a properly controlled experiment, the participants need to be blind to the status of the subjects. You can't make a person from sub-Saharan Africa look caucasian, or vice versa, merely by bleaching or darkening skin, so I don't see how that would be possible. Going beyond this, the fact that sub-Saharan Africa comprises more human genetic variability than the entire rest of the world put together makes experiments of this sort a bit silly, in my opinion. It's like asking whether mammals are smarter than dogs. Looie496 (talk) 17:58, 30 January 2011 (UTC)

(edit conflict) Here at the RD/S we routinely rebuff, for good reason, "scientific" questions built on speculative assumptions ("what if you traveled at 1.5 times c for 5 years in an elliptical path, returning to your starting point..."). This one is in that category for multiple reasons, aside from the patently offensive premise and wording on which it's built (the hypothesis, as stated, is clearly one-sided). We have insufficient scientific basis for (i) how representative these study groups would be of the overall population on which you build the premise, (ii) that the groups could be sufficiently blinded to the study assignments, (iii) that there are "bleaching"/"darkening" procedures that would eliminate racial characteristics giving rise to bias, (iv) that adoption itself does not fundamentally alter linkages among key variables - thus making the adoptive placements an invalid surrogate for race reversal, (v) IQ tests and current measures of "academic performance" are valid measures of intelligence. More importantly, we do not have a basis for believing that these children would not be harmed in the course of this research, so it's unethical as proposed. Bottom line, this proposal is offensive, unethical, and unscientific. -- Scray (talk) 18:06, 30 January 2011 (UTC)

I've put a hat on this, a better idea would be to propose something without the given variables, but the same idea. Tofutwitch11 ^(TALK) 18:11, 30 January 2011 (UTC)

What are "blacks"? What are "whites"? We need a much better definition of terminology before we can proceed. Bus stop (talk) 18:11, 30 January 2011 (UTC)

I have hatted it. Tofutwitch11 ^(TALK) 18:12, 30 January 2011 (UTC)

In the world of science, is there anything that is as taboo as this subject? 88.112.59.31 (talk) 18:45, 30 January 2011 (UTC)

I don't think the word "taboo" is perfectly applicable here. The fundamental problem, IMHO, is that "race" is a social construct, and "intelligence" as broadly defined is impossible to measure (currently). So, science is a very poor domain in which to address the intersection of race and intelligence, and the attempts to do so end up embroiled in meta-discussion. -- Scray (talk) 18:55, 30 January 2011 (UTC)

It's not "taboo". It requires definition. What are we trying to find out? "Blacks" and "whites" are meaningless terms. "Intelligence"—what is "intelligence"? Bus stop (talk) 18:56, 30 January 2011 (UTC)

Interracial cookie. Bus stop (talk) 19:00, 30 January 2011 (UTC)

See Race and intelligence. Further discussion in this realm is unlikely to be fruitful. --Jayron32 19:14, 30 January 2011 (UTC)

I'm unclear as to why this has been hatted, except for the idea that any discussion of the topic is verboten. The OP has clearly indicated that the experiment is fanciful — he is just asking whether it would actually be useful to ferreting out the answers, or if there are methodological problems. I think there are methodological problems (the entire thing is reliant on a 19th-century vision of both race and the nature/nurture debate). But I don't see why we can't talk about that. I suppose it could be viewed as troll food, but I'm wary about preemptively labeling topics that just because they are controversial. --Mr.98 (talk) 20:39, 30 January 2011 (UTC)

But the OP labelled it in the section title with the hypothesis of Blacks are dumber than Whites. That's not a good start. I'd like to see the objective reasoning behind that. And, as Looie496 said, we need this to be a double blind experiment. I would need to hear a lot more about how that was going to happen. HiLo48 (talk) 21:00, 30 January 2011 (UTC)

It's a HYPOTHESIS. A hypothesis isn't meant to be true; it's meant to be tested, and possibly refuted, by the experiment. If a hypothesis is known to be true, it wouldn't be a hypothesis, and there would be no point in performing the experiment. --99.237.234.245 (talk) 21:04, 30 January 2011 (UTC)

Have fun! --Jayron32 20:51, 30 January 2011 (UTC)

Yes, but he could have titled the question as "A scientific test to determine if Whites are dumber than Blacks" as well, but he didn't. Why not? Clearly there is some underlining bigotry here. I agree that instead of hatting it we should discuss it openly and show why such a study (even as a hypothetical study) is unlikely to prove anything useful. Dauto (talk) 21:10, 30 January 2011 (UTC)

What about if we reformulate the question into correlation between IQ and skin color? The second can be measured, and if someone manages to measure the first, we can plot the data... Quest09 (talk) 21:16, 30 January 2011 (UTC)

Take young children from their parents and have them raised by adoptive parents? It has been done before, many times, with tragic consequences for which the Australian parliament has apologised. See Stolen Generations#Australian federal parliament apology. Dolphin (t) 21:42, 30 January 2011 (UTC)

Just a reminder - Jayron32 provided a useful link to our article Race and intelligence, which provides a thoughtful treatment of many of the issues. That would be a great starting point, if this discussion is to be fruitful at all. I'm sure that article could be improved, as well, if someone has lots of energy. -- Scray (talk) 21:46, 30 January 2011 (UTC)

The answer is that no valid scientific experiments can be done on this, because neither race nor intelligence have useful operational definitions. You could perhaps perform a study to compare the performance on standardized tests of people with various amounts of certain skin pigments, and see if there is some correlation. However, this scientific dead-end was abandoned at the beginning of the 20th century, and I don't see why one would want to waste their time with it. I'm not sure why one would suspect that skin pigments would affect test performance. As people have suggested, you might want to take a look at Race and intelligence, where you can learn more about experiments that have been done, as well as allof the bad science that's been done by people trying to prove that "Blacks are dumber than whites". -- Mesoderm (talk) 21:56, 30 January 2011 (UTC)

BTW, A lot of the responses above have been predicated on the fact that race can not be found in DNA, or that race is a social construct. This is not true, see here: http://blogs.discovermagazine.com/gnxp/2010/12/to-classify-humanity-is-not-that-hard/ Ariel. (talk) 22:53, 30 January 2011 (UTC)

It is certainly possible to classify humans based on genetics, however those classifications would not correspond with the usual concept of "race". The article you link to mentioned this: "The various phenotypically “black” peoples of the world, Africans, Melanesians, and some South Asians, do not cluster together. Rather, all non-Africans are separated from Africans by the largest component of variance within the data set." --Tango (talk) 23:17, 30 January 2011 (UTC)

Why are you only using upper class white parents and poor black parents? If you want to eliminate the effect of wealth from your study (which you need to do), you need to have white and black parents with a wide range of wealths. --Tango (talk) 23:17, 30 January 2011 (UTC)

Yikes, I didn't think I would be accused of being a racist. If it makes any difference to anyone, I have dark skin myself and I was sick of racist bigots claiming that black people are dumber than whites. They kept saying how there isn't a black nation on the planet that is modern, that the bell curve for black's performance on IQ tests is worse, that Africa isn't as technologically advanced as white nations because they are inferior, etc, etc. Just awful things, and I was so sick of it, I wanted to at least conceive of a real scientific test that would at least provide some evidence that what they are saying simply is not true. But I want it to be as accurate as possible with proper controlls, so please try to indulge me for the sake of argument. How would I do this if we had no ethical considerations stopping us? ScienceApe (talk) 00:13, 31 January 2011 (UTC)

You would begin with an operational definition for both race and for intelligence. After that, the experiment would be trivial to conduct. The difficult part is creating an operational definition that other people agree on, because science is subject to peer review. As you have been informed many times, both concepts - race and intelligence - are poorly defined, and therefore difficult to use in straightforward experiment. Nimur (talk) 18:33, 31 January 2011 (UTC)

I want to expand on someone's concern above about IQ tests. They do not measure smartness and dumbness. They measure the ability to score well on IQ tests. HiLo48 (talk) 00:34, 31 January 2011 (UTC)

Then we can't use terms like race and intelligence since they aren't well defined. I'm having trouble phrasing a testable hypothesis with terms that have well defined definitions, but here's my attempt,

"Americans with at least 90% of their ancestry descended from Subsaharan Africans have comparable IQ and academic performance to Americans with at least 90% of their ancestry descended from Europeans based on genetics alone" ScienceApe (talk) 19:21, 31 January 2011 (UTC)

All humans descend from a common ancestor. So your definition fails to specify a meaning for "90% of their ancestry descended from (blank)." That leaves an enormous ambiguity subject to interpretation, meta-debate, and so on. As I said, meaningful and scientifically acceptable construction of definitions will be the hard part of your experiment. Nimur (talk) 19:51, 31 January 2011 (UTC)

Well I remember this American researcher coming to Nigeria saying he was researching to show blacks had the same IQ as whites and being asked was that American whites or European whites. Went off in a huff he did. :) Dmcq (talk) 20:37, 31 January 2011 (UTC)

Any suggestions would be helpful Nimur. ScienceApe (talk) 04:07, 1 February 2011 (UTC)

Personally, I don't believe there is any meaningful scientifically valid definition of human race. I think that emphasizing race in scientific and sociological literature solidifies the position of race as an established social norm, indirectly validating all of the social ills associated with racial discrimination. I believe race is just one of many weakly-defined social institutions that are constructed by the gentry with the intent to isolate, divide, and weaken the proletariat; and that when we all finally unite as a species, instead of quibbling over insignificant differences of language, gender, color-tone, and eye-shape, we will be unstoppable. But my opinion isn't at issue here. You can read all about other viewpoints at our article, Race (classification of humans); you can also read scientific racism for perspective. Regarding the definition of intelligence, I think IQ is a pretty darned good indicator of how smart you are, albeit with some well-known flaws; but again, my opinion isn't at issue here. You can read about intelligence, intelligence quotient, and standardized testing to see what professional psychologists and other researchers have previously concluded; and you can make up your own mind. If you really want my opinion, though, I will direct you to this archive from August 24 of last year where I posted several long paragraphs about intelligence in response to another IQ-related question. If you would like references for specific books on human intelligence, or various books expressing different viewpoints about the sociology of human racialism, I can recommend those too. Nimur (talk) 04:40, 1 February 2011 (UTC)

Well that's exactly what I want to prove here, that race is just a social construct. But just asserting that without evidence doesn't say much. There has to be a scientific test to back up that claim with evidence. ScienceApe (talk) 17:48, 1 February 2011 (UTC)

Better add "operational definition of social construct" to your to-do list, then. As well as a meaningful semantic effect of just. –Henning Makholm (talk) 19:59, 1 February 2011 (UTC)

Well that's not my hypothesis, that's just my opinion as it is Nimur's. I don't know what is a good hypothesis. I think this can be tested, I need a testable hypothesis. ScienceApe (talk) 21:24, 1 February 2011 (UTC)

Above, I have tried to differentiate between opinion and scientific fact. I do not believe you can apply the scientific method to test or disprove opinions. Nimur (talk) 19:43, 2 February 2011 (UTC)

If it's a valid hypothesis, sure you can. A hypothesis is an educated guess. That guess can be an opinion. ScienceApe (talk) 19:50, 2 February 2011 (UTC)

The first problem in this experiment is one of definitions. What is "black" and what is "white"? Bear in mind that the usual taxonomic way of defining species or races is cladistic - it assumes that you can say with certainty that two groups are more related to one another than a third group. But within a species, cladistics breaks down. According to ideas I read some years ago, which don't seem to be as popular of late, modern Homo sapiens diverged into three main subpopulations, one of which came to populate western Africa near its connections to Asia minor, and left Africa and colonized all the other continents before the others. But this cladistics is threatened by reports that modern humans, especially outside Africa, may contain a small proportion of genes from Homo erectus^[3] and Homo sapiens neanderthalensis. This would technically make some people, especially whites, a crossbreed of more than one species, though only to a small extent, and perhaps variably between individuals. Who then is more related to who? It gets complicated. And the problem is, these estimates of cross-breeding are all statistical in nature - it's not like a scientist can actually point to your gene sequence and say that you're 3.1% Neanderthal and these are the genes you inherited from them.

Of course there are less technical obstacles of definition. Some people, for example, wouldn't class Egyptians as black, even though they are Africans, or wouldn't class Hispanics and Asians as white, even though they are light skinned, and so forth. Social factors and irrational beliefs determine what people are lumped into a race more than any science.

Another problem that comes up is the issue of what defines intelligence. Some races have a larger proportion of people with weak catechol O-methyltransferase activity than others, and those with the right genotype are reported to do a whole 4% better at a card sorting test than those without. Well, actually, on examination, they do it faster but with more errors (PMID 17689985). So do you define the test as important? Does it matter more to get it done fast or get it done right? I suspect that the race that writes the IQ test will tend to do the best at it.

Now the "newborn" criterion sounds like a nice, clean start - but it clearly is not. A newborn could come from a crack mother or one who plays Mozart to her unborn fetus. It might have received prenatal vitamins or been subjected to amniocentesis and was allowed to survive only because it was healthy. Beyond this, the fetus may carry epigenetic traces of the lives of its parents and grandparents, which potentially might direct it to build (for example) a bigger brain as directed by epigenetic marks on (maybe) insulin-like growth factor target chromatin regions, committing irrevocably to the body's expectation that more nutritional resources will be available throughout the child's life. So you don't have a clean start, and it's very difficult to get one.

Philosophically, one might even question whether a per-individual basis, which favors the largest, most resource-intensive humans, is really the accurate criterion. In a future human species, perhaps people will be smaller, the descendants of African "pigmies", with perhaps a fraction of a percent of their maximum computation rate shaved off on account of fewer neurons, but capable of supporting twice as many in an interstellar ship using the same amount of resources. Is that truly a stupid way to design a human being? Wnt (talk) 02:01, 2 February 2011 (UTC)

Well the the methods to find significant latent variables are getting better so we shouldn't need definitions so much and fast gene sequencing should help with finding groupings. I don't doubt that some group differences will be found that aren't due to deprivation or disease or upbringing but it seems pretty certain they are not very significant compared to the general variability that occurs anyway. As to the original question I guess it would eventually work out as has the contribution of Neanderthal genes contributed significantly to intelligence because there probably hasn't been enough time for a large drift or mutation factor - though of course evolution is affecting intelligence today just as it always has. That would have to be compared to the much larger variation between peoples in Africa, so which particular blacks would one choose? In fact it is perfectly possible that some tribe in Africa will turn out to have the highest innate intelligence by most measures of that. So I'd say if you were doing an experiment like this you'd need to take a large random sample and just try and find what you are measuring from them rather than define it to start with. Dmcq (talk) 10:41, 2 February 2011 (UTC)

How to remove glue?

I was building a Heller Ariane 5 model rocket when, due to defective assembly instructions, I glued together the two halves of the fuel tank before I was supposed to. Now I need to unglue them without risking damage to the structure, so ideally I'd like to remove the glue without applying force on the model. Is it OK to submerge the model in hot water and wait for the glue to decompose?

I am using standard tube glue. Thanks everyone. Leptictidium (mt) 18:01, 30 January 2011 (UTC)

"standard tube glue" is not very specific, but in context I assume you're referring to the glue generally used for plastic models, i.e. butanone-based adhesive. There are de-bonding agents sold in hobby stores for this purpose; I'm not confident that hot water will achieve the results you want because butanone works by dissolving a bit of the polystyrene and allowing the two parts to fuse, but if it won't damage your model then you could try it. -- Scray (talk) 18:33, 30 January 2011 (UTC)

I am not sure what the best way to proceed would be. One thing that comes to mind is to allow the two glued halves to remain glued together, and then to cut them apart with a tool like a Dremel rotary tool. Of course this is a very expensive approach, so you will probably want to consider other alternatives. But I just thought I'd mention the possibility of this. I really don't know much about the exact situation. But I know sometimes glues can be difficult to reverse once they have set. Bus stop (talk) 18:40, 30 January 2011 (UTC)

You can possibly try to carefully pry them apart with an old style plain razor blade. Be careful with the remaining 9 fingers! --Stephan Schulz (talk) 19:27, 30 January 2011 (UTC)

Acetone (i.e. nail polish remover) is often useful for dissolving glues. Use a cotton swab to spread some (liberally) over the glued area, and then after it's had a few minutes to work, take a razorblade to it. It might only dissolve partway through the glue the first time -- if so, cut in as deep into the glue as you can, and then apply more acetone and repeat. -- Mesoderm (talk) 19:34, 30 January 2011 (UTC)

Note that if we're talking about a welding glue like butanone, which is really a solvent as I noted above, then any solvent that can dissolve the joint may damage, weaken, or at least deface the material with which you're working. Any "liberal" application might be tested on a throw-away piece of the same material to ensure you get the results you desire. -- Scray (talk) 21:20, 30 January 2011 (UTC)

To answer your question properly you're going to have to tell us what "standard tube glue" is. Ariel. (talk) 22:45, 30 January 2011 (UTC)

EEK! I would be especially careful of acetone as it could dissolve more then just the glue! Solvents can soak into the plastic and melt them or soften them to the point where they become impossible to set. I would try the very careful razor approach. Vespine (talk) 01:23, 31 January 2011 (UTC)

Thanks to all for pointing this out -- I've used acetone to remove glue in the past without problems, but I'll definitely be more careful in the future. What types of plastics specifically do you have to worry about? -- Mesoderm (talk) 02:23, 31 January 2011 (UTC)

Actually, I found the answer to that question. Here is a list of plastics that can/can't be used w/ acetone:

Acetone-Plastic Compatibility List

Acetone, pure - Ketone, Aliphatic

• LDPE at 20C ..... Little or no damage after 30 days of constant exposure.
• HDPE at 20C ..... Some effect after 7 days of constant exposure.
• PP at 20C ..... Some effect after 7 days of constant exposure.
• PPCO at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• PMP at 20C ..... No damage after 30 days of constant exposure.
• PETG at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• FEP at 20C ..... No damage after 30 days of constant exposure.
• TFE at 20C ..... No damage after 30 days of constant exposure.
• PFA at 20C ..... No damage after 30 days of constant exposure.
• ECTFE at 20C ..... No damage after 30 days of constant exposure.
• ETFE at 20C ..... No damage after 30 days of constant exposure.
• PC at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• RPVC at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• PVCT at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• PSF at 20C ..... Some effect after 7 days of constant exposure.
• PS at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• PVDF at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• PMX at 20C ..... No damage after 30 days of constant exposure.
• TMX at 20C ..... Some effect after 7 days of constant exposure.
• PET at 20C ..... Some effect after 7 days of constant exposure.
• PMMA at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• SAN at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• PK at 20C ..... Data not available.
• FLPE at 20C ..... No damage after 30 days of constant exposure.
• TPE at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• SILI at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• XLPE at 20C ..... Immediate damage may occur. Not recommended for continuous use.
• NYL at 20C ..... No damage after 30 days of constant exposure.
• LDPE at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• HDPE at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PP at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PPCO at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PMP at 50C ..... No damage after 30 days of constant exposure.
• PETG at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• FEP at 50C ..... No damage after 30 days of constant exposure.
• TFE at 50C ..... No damage after 30 days of constant exposure.
• PFA at 50C ..... No damage after 30 days of constant exposure.
• ECTFE at 50C ..... Little or no damage after 30 days of constant exposure.
• ETFE at 50C ..... Little or no damage after 30 days of constant exposure.
• PC at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• RPVC at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PVCT at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PSF at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PS at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PVDF at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PMX at 50C ..... No damage after 30 days of constant exposure.
• TMX at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PET at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PMMA at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• SAN at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• PK at 50C ..... Data not available.
• FLPE at 50C ..... Little or no damage after 30 days of constant exposure.
• TPE at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• SILI at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• XLPE at 50C ..... Immediate damage may occur. Not recommended for continuous use.
• NYL at 50C ..... No damage after 30 days of constant exposure.

So basically, if you know what type of plastic the model is, you could check this list and see if it's safe to use acetone.Mesoderm (talk) 18:12, 31 January 2011 (UTC)

I have rolled your list up for convenience. Can you provide a reference citation for that list? Nimur (talk) 21:00, 31 January 2011 (UTC)

Just to be on the safe side, you can always "patch test" the solvent first on the inconspicuous inside of a part or on the disposable frames that hold the pieces. Vespine (talk) 22:04, 31 January 2011 (UTC)

@Nimur: Thanks for collapsing the list -- sorry I didn't think about doing that. I got the information from here (Select "Acetone, pure" and "All materials/resins", and don't select anything from "chemical class"). -- Mesoderm (talk) 02:15, 1 February 2011 (UTC)

Codeine and its counterparts

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page. If you have a question about drugs to take if you have an allergy, please ask a physician or pharmacist.

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis or prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page. If you have a question about drugs to take if you have an allergy, please ask a physician or pharmacist.--~~~~

I have taken this discussion to the Ref Desk talk page. Bielle (talk) 22:14, 30 January 2011 (UTC)

Highbeam's offer of scientific magazines

Does Highbeam have many top scientific magazines among its offer? Quest09 (talk) 21:04, 30 January 2011 (UTC)

Here's a list of the science magazines they have. Red Act (talk) 21:12, 30 January 2011 (UTC)

Well, I can't seem to find any which is really highly prestigious.Quest09 (talk) 21:18, 30 January 2011 (UTC)

Agree - no first-tier journals. The latter are a bit hard to define dogmatically, but ScienceWatch, Eigenfactor, and Science Gateway have lists that might be relevant. -- Scray (talk) 21:40, 30 January 2011 (UTC)

Big alignment

I heard that our solar system and all the planets and the sun will be aligned with the center of the milky way galaxy in next year if so will this be noticeable. --93.107.73.219 (talk) 21:11, 30 January 2011 (UTC)

• It's not the case, and it wouldn't be noticeable everyday effects even if it were. After the moon and the sun, the gravitational effect of heavenly bodies on the Earth is basically negligible. Jupiter is the next most significant, and you've never been affected by its gravity nor observed the effects of such, and we align with Jupiter roughly once a year. — Lomn 21:45, 30 January 2011 (UTC)
• This is just part of the 2012 Hoax. A large part of the sordid story is at 2012_phenomenon#Galactic_alignment. In short, there is no particularly exciting multiple conjunction in 2012. The Earth, the Sun, and the galactic center line up roughly once per year. --Stephan Schulz (talk) 21:52, 30 January 2011 (UTC)

If you use a telescope and check the position of the planets, you will notice where they are, but why would it matter? --Lgriot (talk) 13:27, 31 January 2011 (UTC)

It's much easier to photograph planets when they're nearby. Stunning and artistic photographs, such as this one, featured at NASA's Astronomy Photo of the Day in April 2000, are only possible during syzygy or near-syzygy. Here's a nice gallery of December 1, 2008 Moon Venus Jupiter alignment, photographed throughout the world. A few scientific observations are possible during planetary occultations; radio shadow, atmospheric refraction spectroscopy, and other scientific measurements are possible as a one object traverse across the limb of another object. Otherwise, planetary alignments have no special significance. Nimur (talk) 22:12, 31 January 2011 (UTC)

An approximate planetary alignment can also help make it possible to use the slingshot effect to have a spacecraft efficiently do a planetary flyby of multiple planets, as in the Planetary Grand Tour of Voyager 2. Red Act (talk) 23:14, 31 January 2011 (UTC)

Subterranean flows of water (contains spoiler of Philip Pullman's The Tiger in the Well)

Starting on page 265 of Philip Pullman's The Tiger in the Well is talk of subterranean rivers and springs and whatnot. Mentions of houses crumbling into such bodies of water (and sewage and other wastes) after storms seem to be based on historical fact. Where can I read more about this phenomenon, both as a matter of fact and of history. Thanks. 66.108.223.179 (talk) 23:06, 30 January 2011 (UTC)

See Underground river, Sinkhole, Cenote and be sure to follow the "See Also" links from those articles. Ariel. (talk) 02:03, 31 January 2011 (UTC)

Following one such link: Subterranean rivers of London. 66.108.223.179 (talk) 01:42, 2 February 2011 (UTC)