Wikipedia:Reference desk/Archives/Science/2007 April 27

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April 27

Gloster F.5/34 with Merlin engine?

I was reading up on the Gloster F.5/34 and was wondering: could the Gloster F.5/34 be fitted with a Merlin engine? Would that have allowed it to enter service? --Blue387 00:32, 27 April 2007 (UTC)

Question about the Integrity of the information, re: Chemistry

Dear Sirs or Madames:

I am a health science student and I am new to this site. If I am to understand this correctly, this site offers information, that has been donated/offered via its readers/site visitors. I am curious about the validity and the integrity of the site, if I am doing research for the projects that I am studying. Does anyone question the articles, preview them, or verify that they are possibly valid or invalid? I would be most upset if I have been visiting, what I believe to be an "informational site," only to discover, it was put together for mere humor.

Please respond, as I am searching for valid sites, and information that I need for my research.

Respectfully,

jo 01:54, 27 April 2007 (UTC)jo

You may be interested in reading Wikipedia:Researching with Wikipedia. In general, if you're writing a scholarly paper, you probably do not want to use tertiary sources like encyclopedias. Splintercellguy 02:04, 27 April 2007 (UTC)

Not quite. You can use Wikipedia, but you should not cite Wikipedia or any other tertiary source. Use Wikipedia to get an overview and to find valid secondary sources and/or primary sources. Then, read the primary and secondary sources and cite them. When you use Wikipedia to get an overview, you should be skeptical, because "anybody can edit." Therefore, you should look at the history and discussion pages for the articles you read to form your own opinion about the validity of the information, even before you look at the secondary sources. In this regard Wikipedia is more "reliable" than other tertiary sources such as paper encyclopedias or web pages, since they do not have an equivalent mechanism. -Arch dude 04:10, 27 April 2007 (UTC)

Typically, I've found the articles on chemistry (and most sciences) to be pretty accurate. However, there is no way I would use Wikipedia for serious research. I use it for clarification on some things in textbooks and for help with homework, as well as for general curiosity. Beyond that, even "normal" encyclopedias aren't good enough, and you need real sources (scientific journals, textbooks, etc). --Bennybp 04:01, 27 April 2007 (UTC)

Wikipedia does occasionally suffer from vandalism, but the average vandal is far more likely to put "(insert friend's name here) eats poo" in an article, than to change the boiling point of benzene. Most vandalism is quickly fixed. StuRat 04:08, 27 April 2007 (UTC)

As mentioned, you should seek primary sources if you intend to do serious research; encyclopedias are great for overviews. As far as the vandalism problem: clearly we can disregard "poo" vandalism in any article; it is easy to spot. But there are other relevant vandalism issues; I categorize them into two types - "factual errors" and "bias."

The first is the deliberate vandalism - (StuRat says that the boiling-point of benzene is rarely vandalized; but I recall the land area of North Carolina decreasing by 1 square mile slowly and steadily; the average temperature decreased by one degree (by the same vandal editor), and a mystical statistic which started decreasing. (These particular edits are insidious and easily slip below the radar, especially if there are intermediate edits which make it hard to "diff"). These subtle factual errors might be missed by a trusting reader; and may persist for a long time before anyone actually notices.

But there is a different "vandalism" problem, which yields systematic bias regarding the presentation of certain ideas. This is problematic in "fringe" science such as bioelectromagnetism (dramatically improved since its creation), and electronic voice phenomenon; no reputable scientific publication would deign to print this rubbish. But Wikipedia is not censored, and we seek verifiability instead of truth; and as long as these articles do not explicitly violate factual evidence, they may continue their existence.

If you are a researcher, you should worry about these issues regardless of your source; it is silly to pretend that a primary-source peer-reviewed publication is to be blindly accepted. Science must be independently verifiable (whether it is a published fact or a repeatable experiment). </rant>. Nimur 05:30, 27 April 2007 (UTC)

Minor note - the above vandalism examples are several weeks old and have already been fixed (as of the time of this writing). Nimur 05:35, 27 April 2007 (UTC)

Articles about politicians, history, or current controversial events have a greater chance to be biased, but as I experienced, scientific articles are very trustworthy. --V. Szabolcs 08:11, 27 April 2007 (UTC)

Catching "Colds"

When I was younger I thought that people got sick from the cold. Later I learned that this was completely false, that people get sick due to bacteria. Then I found out that the reason people get sick during the winter much more often than during the summer time was due to the fact that people spend more time indoors in unventilated areas during the winter. Similarily, students tend to get sick near the begginning of the school year for the same reasons. But from parents and others I was always told to keep warm otherwise I would get sick. So I thought that perhaps what really happens was that the bacteria are constantly attacking the body and being repelled by the immune system but that the immune system weakens significantly when the body is extremely cold and is therefore more susceptible to catching a "cold". Is there any truth to this? Also, from personal experience, I have found that I (and others that I know) get sick when I get my hair wet and don't dry it. (eg taking a shower late at night, going swimming etc) The next day I get sick (sometimes, but since I don't get sick often there must be some correlation). Why is it that people get sick sometimes when they are wet?70.49.139.17 02:40, 27 April 2007 (UTC)

Just a nitpick, but colds are typically caused by a virus, not bacteria. I believe they've tried to do some research on whether or not being cold results in a cold (and if so, why) but they were unable to prove anything. The article on the common cold has some info under "Cold as a misnomer". --Bennybp 03:56, 27 April 2007 (UTC)

I believe that immunosuppression is a factor in catching colds, as many other diseases. Also, many results from cold, dry whether, like cracked, chapped lips, can offer another method of entry for viruses. I would go so far as to say that everyone has cancer all the time, but that their immune system destroys the cancer cells as soon as they are found, so it never gets to the point where the cancer is even noticeable, until the immune system goes down, for whatever reason, and the cancer grows. StuRat 04:05, 27 April 2007 (UTC)

StuRat, I don't necessarily agree or disagree with your cancer hypothesis; but do you have any source literature which might back that theory up? Nimur 05:39, 27 April 2007 (UTC)

It's based on an observation that many people "get cancer" after their immune systems become depressed, without exposure to any unusual carcinogenic agent. See David_Vetter#Death for an example of someone without an immune system, who quickly died from cancer after being exposed to the very common and normally non-lethal agent, the Epstein-Barr virus. I believe that this virus, and many other agents, cause cancer in almost everyone, but that this cancer is wiped out by the immune system in most people. StuRat 16:30, 28 April 2007 (UTC)

Correlation is not causality. If you go to bed with wet hair after a shower, you are vary likely is a stressful situation: yo are nto getting enough sleep and you do not have enough free time. Swimming pools and locker rooms are very good environments for bacteria, so wet hair after swimmoing is also correlated with colds. And yes, prolonged exposure to cold temperatures can stress your system. -Arch dude 04:19, 27 April 2007 (UTC)

Like many systems that live in the world that orbits the sun once a year, the virus responsible for the flu has a cycle. New flu viruses naturally arise during certain times of the year. Cold may correlate to the flu but not be causal in any way. --Tbeatty 06:06, 27 April 2007 (UTC)

Whoa whoa whoa, wait, what? While I believe personally that temperature has a bit of effect on your body, I thought it was a proven fact that cold and flu virii survive about 2 weeks in colder weathers, as opposed to a few hours in warmer weather (thus fevers)? --Wirbelwindヴィルヴェルヴィント (talk) 08:00, 27 April 2007 (UTC)

Hold on are we talking about the common cold or the flu? They're both caused by viruses and have some symptoms that are similar and are both caused by viruses but they're not the same thing and lumping them together may be confusing. We already have people talking about bacteria... Nil Einne 13:34, 27 April 2007 (UTC)

Your assertation that flu viruses natural arises during certain times of the year seems potentially confusing to me. Cycles that occur in living organisms don't just exist apriori, they are generally regulated via some means. (Having studied regulation in plants to a limited degree, I can tell you these systems are not simple...) There does appear to be a correlation between both colds and the flu and colder weather. This is AFAIK observed in both hemispheres and also in non-temprate countries were the correlation is with the rainy seasons not winter. (In all cases, it could also be related to the level of sunlight or other factors associated with these seasons not just temperature.) Many influenza viruses have been sequenced as I assume many of the viruses which cause colds. As far as I'm aware, they aren't known to have temperature or light regulation. Remember that any regulation would be host dependent in any case. So I don't see any reason to assume there is any internal regulation but the apparent cyclic nature of both may be due to one or more external factors many of which have been mentioned. Immunosuppresion, closer contact between hosts, how long external viruses can survive etc. Nil Einne 13:46, 27 April 2007 (UTC)

Point of order - there is some correlation between the cold/flu season and cold weather, but only on this side of the equator. Influenzas typically originate in SE Asia where the seasons run differently (they are also north of the equator but have an equatorial type of climate, not the four seasons we have in the temperate zone).

Like lots of people, I've noticed that there seems to be some correlation between being out in the slush and getting a cold that night, but here's the thing - I don't think colds run that quickly. If I'm shovelling the white stuff after supper and then sniffling and coughing before bed, I must *already* have been on the verge of succumbing. Matt Deres 17:44, 27 April 2007 (UTC)

distillation

Why is copper used in cooling and condensing the alcohol and water vapor that comes from heating corn mash? Can plastic or aluminum tubing be used instead? 71.100.8.252 04:38, 27 April 2007 (UTC)

High thermal conductivity and it's cheap and easy to obtain and work with. Aluminum could probably also work assuming there aren't any chemical incompatibilities I'm not thinking of (there may be, so check). Most plastics don't conduct heat particularly well, so they wouldn't be very good for this purpose. -- mattb 04:51, 27 April 2007 (UTC)

The alcohol vapor would squirt out of the end of the plastic tube and no delicious corn likker would drip down into the jug. Edison 05:02, 27 April 2007 (UTC)

I've already performed this experiment and collected a reasonable amount of distillate. I used plastic tubing and it worked great. I just need to know if the distilllate would be okay to drink and whether other types of tubing would cause health problems. Seems like I read or heard somewhere that anything besides copper does something to the distillate that was responsible for people going blind from drinking the distillate produced by bootleggers? 71.100.8.252 05:48, 27 April 2007 (UTC)

I don't think aluminum would work. I believe it may dissolve in or be corroded by ethanol (or at least the aluminum oxide coating). I'm pretty sure methanol dissolves the coating, and so ethanol probably would too, being very close (chemically speaking). --Bennybp 05:18, 27 April 2007 (UTC)

I am not sure that this plays a part but both aluminum and copper get oxidized when exposed to air. The thin copper oxide is a solid and essentially protects the unoxidized copper underneath. I believe the aluminum oxide is not as stable and will breakdown and weardown with heat and age (heat may force the aluminum to be consumed). I suspect this would be both a corrosion and contamination issue. This theory is based purely on the practical application of a compound called "NoAlOx" on aluminum power delivery wires and is required by code. Copper requires no such application. I also don't know the differences in coefficients of expansion during heating. Does Aluminum physically change length more than copper? --Tbeatty 05:32, 27 April 2007 (UTC)

Copper his expensive and corrodes because of the acid contained in the vapour. Exchanging it every few years is necessary. Stainless steel is what they liked to use, but the taste changes and they stopped using it. (docu from scottland).---Stone 05:43, 27 April 2007 (UTC)

Please contact a distillation expert. We at the Reference Desk cannot give advice for how to distill spirits for consumption. Moonshine lists some of the ways that the output of a still can be harmful: "Methanol and other toxic alcohols can occur naturally in distilled spirits and are called fusel oils." Commercial distilleries test for these products to make sure the liquor does not contain them. Every year there are reports of people dying or going blind from drinking homemade distilled spirits. Edison 13:29, 27 April 2007 (UTC)

Pure ethanol can readily leach the plasticizers out of some types of plastic tubing. Whether that would happen at the concentration of ethanol in your distillate, I'm not sure. The type of plasticizer used in your tubing is going to be very difficult to find out, so the health effects of using plastic tubing for a distillate that you want to drink with be a big question mark. --Ed (Edgar181) 14:44, 27 April 2007 (UTC)

Our research has determined the particular plastic that is being to distill ethanol is PE and we think it is HDPE rather than LDPE as sold as icemaker tubing by Home Dpot which is also the plastic commonly used to ship and store 90% isopropyl alcohol, distilled white vinegar and many, many other common food and household products. If it is not safe we would like to know. 71.100.8.252 18:17, 27 April 2007 (UTC)

If it were me, I wouldn't risk it, and I'm a chemist! There are many things that can go wrong, including methanol and other impurities that can cause serious harm, and unless you have the equipment to test the results (GC-MS, HPLC) I wouldn't recommend it. As said before, if you are serious about setting up a still for yourself, get some guidance from someone who knows much more about making and distilling alcohol. Or at least get one of those do-it-yourself kits with the proper materials and instructions (I know they have some for making alcohol, but I don't know about distilling). --Bennybp 21:19, 27 April 2007 (UTC)

I "risk" it, and i am also a chemist. copper is used because it scrubs out the sulfur compounds that distill over (low molecular weight thiols and disulfides). and from a practical viewpoint its relatively easy to cut, solder and bend into complex shapes. but now days it is also very expensive, but the economics begin to work out fairly quickly if you have any sort of reasonable level of production. another popular material is stainless steel, but that is very hard to work, and often people will put copper mesh or foil on the inside of the column anyway to get the same scrubbing effect. I wouldn't recommend plastic for the whole rig, but a lot of stills have a plastic barrel as a pot, fitted with electric heating coils. A good site to get you on your way is here[1]. NB: i am not advocating illegal activity, home distillation of alcohol is legal in NZ. Xcomradex 00:39, 29 April 2007 (UTC)

Couldn't you use Schroedinger's cat to test the drink for Methanol? cat dies, don't drink. It's practically the same experiment :) --Tbeatty 03:56, 30 April 2007 (UTC)

basic questions about earth's orbit

Sorry if these are moronically basic questions, but I couldn't find the answers in the article on Solar system, Earth, etc.

The Earth's distance from the sun is 93 million miles... is that at apogee? Or on average?? What is a good analogy for this distance (for example, how many trips across the United States would this take, etc.)

Is there a round number for the Earth's velocity in something more useful than approximately 93 million miles a year?

Babrahamse 13:52, 27 April 2007 (UTC)

First to clarify the terminology: "apogee" is for orbits around the Earth. For orbits around the Sun the word is "aphelion".

93 million miles is the average (mean) of the aphelion and perihelion distances, otherwise called the semi-major axis of the orbit. The aphelion distance is 94.5 million miles, perihelion 91.4 million. These numbers are given (with more digits) in the box in the Earth article.

Taking a trip "across the US" to mean New York to Los Angeles, the National Geographic Road Atlas says the driving distance is 2,776 miles. Divide 93 million by that to get the number of trips across the US.

The Earth's orbital speed is not 93 million miles per year. 93 million miles is the radius, and you want the circumference, which is 2 times pi times that number (approximately, since the orbit is not a circle). You can find the correct orbital speed in metric units in the same place I mentioned. In miles per hour the average speed works out to about 66,600 mph.

--Anonymous, April 27, 2007, 14:07 (UTC).

Beaten to it! Anyway, the part of my answer not given by the anon is that if you drove from LA to NY and back (funnily enough, I chose the same example) every day, then in about 46 years you would have travelled the distance from the earth to the sun. For the earth's speed, if you drove from LA to NY at that rate, you would make the journey in two and a half minutes. Hope those help bring the numbers down to earth. Algebraist 14:20, 27 April 2007 (UTC)

In the Earth article the data for Earth's orbit are given for a specific epoch. We are currently in an epoch when the eccentricity of Earth's orbit is fairly low (see). I'm not sure how that influences any answers to the "Or on average?" question. What if you averaged over the past 4,000,000,000 years?
--JWSchmidt 17:24, 27 April 2007 (UTC)

Catching colds again

Speaking of catching colds, I do sometimes sneeze when I'm cold, and get a runny nose, and generally show flu/cold type symptoms albeit briefly, and I'll stop when I'm warm again. Is this common? I've heard about the erroneous idea that colds were thought to come from cold weather since I was very young, as well as knowing the modern explanation that this was because people were in confined spaces in Winter, and have always found this to be a silly way of perceiving historic understanding. It seems much more plausible that the reason colds (viral) were associated with cold weather was because cold weather could bring on cold-like symptoms (and presumably if you stay in cold weather, it would stress you and your immune system and you could well catch a cold when you end up a confined space with people with colds). Is it common to sneeze and have to blow your nose merely from being cold? —Pengo 13:57, 27 April 2007 (UTC)

Sorry I don't have an answer to your question, but instead I'd like to ask a similar one. A recent newspaper article I read asserted that colds are more common in Winter, not because of lower temperatures, but rather because people are confined indoors more and therefore they are more likely to be around other people who are contagious. If that's true, are colds more common in the summertime in places like Phoenix, Arizona where people are confined indoors more often in the Summer than in Winter? Or are colds equally common throughout the seasons in places like Florida or Southern California where people are outdoors throughout the year? Deli nk 14:03, 27 April 2007 (UTC)

I suspect that when you are infected by a cold virus your body is responding to the virus in many ways, including those that result in release of histamine and cause fluid to enter the nasal sinuses. If you "get cold", you body may allow more blood to reach the sinuses, resulting in increased movement of fluid into the sinuses making your runny nose worse. When you warm up again, less blood flows, less fluid enters the sinuses, you notice that your nose is not running as much. --JWSchmidt 17:18, 27 April 2007 (UTC)

Yea, I heard that in the cold, the blood vessels in your sinuses dilate, to allow more blood in which warms up the air you breathe before it gets to your lungs. Aaadddaaammm 00:14, 28 April 2007 (UTC)

Just to touch on Deli nk's question... I would think that you probably wouldn't see a rise in colds in Phoenix during the summer time because of the lack of humidity. Different bugs have different weaknesses, but extremes of dryness and extremes of heat are among the most common. While you cuold obviously still trade germs while inside the lovely air conditioning, every time you spent time outside you'd be putting the germs on your skin under a lot of strain. As for Pengo's question: I'm not sure how widespread it is, but I sure get cold-like symptoms when I'm out in the cold for long periods. As the folks above noted, a big part of it your nose and sinuses trying to maintain their optimum moisture level. Matt Deres

TORNADO!!!

Resolved

 – Userpage deleted, User blocked--VectorPotential^Talk 19:44, 27 April 2007 (UTC)

Hi....help! There is a tornado headed directly to my location now I have no idea what in the hell to do! It looks like it will arive in 1-3hrs and it is growing in size!--Bakaneko07 17:42, 27 April 2007 (UTC)

Check out the safety section in Tornado for information. I would go in the basement, if you've got one. bmk

Bakaneko07 created his user page, advertising his child porn web site, 9 minutes before posting this question. 169.230.94.28 19:04, 27 April 2007 (UTC)

Yeah, I would definitely have an admin check his userpage out. --wpktsfs 19:29, 27 April 2007 (UTC)

Although I'm not sure this merits his question not being answered, his question was answered. [Mαc Δαvιs] ❖ 20:22, 27 April 2007 (UTC)

Firstly, you can't really have a tornado bearing down on you for an hour or more - they appear - smash stuff for a few minutes and then fizzle out. Even when they are longer-lived, nobody can predict where they will end up - so if it's an hour away, you are very, very unlikely to end up in it's path. However, if you know that there is a tornado coming - the best advice is to find a downstairs room (less distance to fall if the house collapses) - preferably away from windows (glass flying at you at 200mph is no fun) - preferably in a closet or bathroom (because the wooden bracing in the walls is closer together in those places and the pipework and ceramics in a bathroom offer marginally more protection). If you have time, drag a matress into the bathroom - lay in the bath and cover yourself with the matress to create a zone where debris will find it hard to reach. Or alternatively (as most of us do in what is so charmingly known as "Tornado Alley") is to follow that advice the first couple of times one comes by - then ignore that damned thing and place your faith in statistics. I've actually driven my car right under a tornado that had not yet "touched down" - since I only have a convertible - the 2" hail made that rather more exciting than I wanted! SteveBaker 22:00, 27 April 2007 (UTC)

There was one summer when I was working in a location that had 4 tornado warnings. The thunderstorms all followed the same west to east path, hitting the counties to the west of us and then the county where I was working. It got very old. Shear bad luck or the topography or the patterns of air currents in the upper atmosphere? Edison 22:21, 27 April 2007 (UTC)

two personalitys one body

as per the questions above with the two headded snake, i tried to enter a new question but it was arcived or something like that [2] anyways the question was what if the girls marry 2 diffrent guys? would it be called cheating and wouldnt the guys get into a fight about it? User:Maverick423 If It Looks Good Nuke It 22:42, 27 April 2007 (UTC)

The question is still up there: Wikipedia:Reference_desk/Science#Snakes Rockpocket 23:05, 27 April 2007 (UTC)

But since its quite a deviation from the original question, it may as well have its own section. The legal precedent shouldn't be altered by each one marrying someone different. If they could take their driving test individually, though obviously both had to take part on each occasion, why couldn't a different individual marry each of them independent of the other (even though the other would have to be involved physically.) The legal precedence would be that they can identify their shared body as representing one or the other at a given time - as they must have done when they turned up for their driving test - so they can do the same in marriage (and in marital relations). Would the guys fight about it? Who knows. Though one might speculate that the people involved in this hypothetical situation would be pretty sensitive to its challanges (its not like you wouln't notice they are conjoined twins, is it?) thus they might realise fighting doesn't solve the perceived problem.

I think the more challenging question for the legal system would be if they both chose to marry the same person. Technically, he would he be guilty of polygamy, I suppose. Rockpocket 23:19, 27 April 2007 (UTC)

In the US, we are (mostly) a common-law system. This means that the law is silent until a case occurs. As caring and sympathetic humans, we should all hope that a case involving these poeple never occurs.They will choose one husband, or two. they will have children, or not. In the best-case scenario, no real confilict will ever arise. If these individuals are wise, they will enter into a binding contract that specifiec in excruciating detail what all of the consequencse will be. Bless them. Pray for them. Pray that a conflict never arises. -Arch dude 02:46, 28 April 2007 (UTC)

I find this 'subject' quite intriguing and, while thinking about it, another 'angle' came to me: What do you think would happen to 'them' if one committed a crime where jail-time would have to be served if convicted? Of course, I`m presuming that only one of 'them' had committed the crime. i.e. only one of them 'pulled the trigger'. Would the other 'automatically' be partly to blame? If 'each' could be asleep independently, and the 'waking' personality committed the crime, then what? Surely you couldn`t convict, and thereby send both to jail? To go even further, what if itwere a capital crime and the death penalty is given??? These questions are probably not answerable, but still, very intriguing, no? Thanks. 64.230.233.222 04:36, 28 April 2007 (UTC) Dave

It would be unlikely to happen, because they each control one side of their body. Therefore they couldn't walk anywhere, or do any task that involves two hands, without co-operating. I suppose one could, theoretically, pull out an already loaded gun and shoot someone without the other's prior knowledge. That would, indeed, leave a fascinating legal conundrum. Rockpocket 19:27, 28 April 2007 (UTC)