Wikipedia:Reference desk/Archives/Science/2008 October 12

= October 12 =

Image licensing
HI,I AM DOING THIS PROJECT ABOUT NORTH AND SOUTH POLE AND I JUST WANT TO ASK YOU THAT IF I CAN PRINT  SOME PICUTER                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     THANKYOU VERY MUCH               FROM  MEENAKSHI  —Preceding unsigned comment added by 68.183.31.96 (talk) 00:18, 12 October 2008 (UTC)


 * Yes
 *  Sp in ni ng  Spark  11:23, 12 October 2008 (UTC)
 * Smallprint for lawyers to read
 * Almost every photo on Wikipedia is freely licensed. This means that you may re-use or modify the photos (including printed copies).  For any specific image, check its license information, which will provide details on what the image owner requires regarding re-use.  Also see Image copyright tags for general information.  In general, if you are using these photos for a school project, that would be permissible under most of the image licenses on Wikipedia.  Nimur (talk) 00:32, 12 October 2008 (UTC)


 * I have no idea what cutting pie has to do with the North and South poles....--el Aprel (facta-facienda) 00:36, 12 October 2008 (UTC)


 * Hi! It's OK to print most pictures that are on Wikipedia - but there are a few exceptions. All of the photos at our South pole, Antarctica, North pole and Arctic are OK to copy.  You can also go to our sister site "WikiCommons" - and type "North pole" or "South pole" into the search box...you'll find also that there are "categories" of photos: Category:South_Pole and Category:North_Pole.  There is also a bunch of photos of the Amundsen-Scott south pole station.  All of those photos are OK to print.


 * If you need to know about other pictures on Wikipedia, what you need to do is to click on the photo you are interested in and when the image's own page pops up, it should look a bit like this one: HERE. Now you need to scroll down and look where it says either: "Licensing" or "Permission (Reusing this image)" - if it says something about "Fair use" then it's not OK.


 * SteveBaker (talk) 00:47, 12 October 2008 (UTC)
 * Though honestly if you are using it in an elementary school assignment I don't think anybody cares about the copyright status. --98.217.8.46 (talk) 03:29, 12 October 2008 (UTC)
 * You mean ANY school project? Who's going to sue you because you used, say, Coca-Cola's logo in a school assignment? That would just make the copyright owner look bad. --M1ss1ontomars2k4 (talk) 04:06, 12 October 2008 (UTC)
 * Well, I left out "any" because I could imagine some school projects in some scenarios where stuff like that could matter. (A dissertation is a "school project", in a sense, and you have to be mindful of copyrights with those.) But yeah. Really not worth worrying about for run-of-the-mill assignments. Falls under fair use pretty solidly. --98.217.8.46 (talk) 13:25, 12 October 2008 (UTC)


 * It is important to teach a respect for the copyright law. If kids get the idea that they can copy anything anytime - they are going to get into a lot of trouble in later life.  Copyright laws are annoying and a big pain in the butt - but they are laws - and it's important that kids realise that.  The idea that copyright holders don't "care" about little things like school projects is likely true - but that's not true of trademark law - where if you don't actively pursue infringements you can lose your ownership of them.  Hence, CocaCola may well be forced to pursue even "irrelevant" infringement at the level of a high school project. SteveBaker (talk) 14:58, 12 October 2008 (UTC)
 * Oh yeah, sorry, I was forgetting about all those CocaCola billboards at the North Pole and the pictures of them in Wikipedia to catch out the unwary. Context! please.  Sp in ni  ng  Spark  18:24, 12 October 2008 (UTC)
 * Large corporations will most certainly sue schools over misues of their trademarks: Disney has done it to day care centers and most other companies will as well. They will also always win, and it isn't only because they have lots of high powered lawyers.  Under intellectual property law, there is a concept known as "trademark dilution"; once a trademark (be it a word, logo, or character, basically any symbol of your company) has entered the common lexicon, you can no longer use it as a trademark.  Basically, if Disney did NOT aggressively defend its trademark, and was shown to allow, say, a day care center in Florida to use Mickey Mouse in their logos without proper permission, then it would set a precedent for anyone to use it.  Disney cannot be selective in allowing infringements of its trademarks; it either has to expressly require that all uses are licenced, or it has to allow all uses by anyone for any purpose.  As a result, large corporations can and do pursue these cases... --Jayron32. talk . contribs  18:35, 12 October 2008 (UTC)
 * Jayron is exactly right. Consider for example a school student project which then becomes entered in the state science fair and wins, subsequent to which prominent newspapers publicize the event c/w pictures. The way copyright law works is that you have to pursue any violations that come to your attention, otherwise you fall foul of the equitable doctrine of laches and your trademark becomes public domain. Aspirin and kleenex are examples of former trademarks that became common names. Companies don't want to pursue daycares, they have to. Franamax (talk) 04:56, 14 October 2008 (UTC)

What colour would you say best describes the upper mandible of a male Eclectus?
Question as topic. A user has suggested that 'candy-corn-coloured' (as stated in the article at present) is less than ideal. I'm inclined to agree.

Any suggestions? I'm thinking 'saffron' - though I'll readily admit that colour naming is not my strong point... --Kurt Shaped Box (talk) 02:52, 12 October 2008 (UTC)


 * It looks like scarlet (or orange) with a bright yellow tip, though I see what the phrase "candy-corn-coloured" means when I look at the photograph of the parrot. Just "candy corn", without the "coloured", might work for those who have seen candy corn (and for those who haven't, click here ) but candy corn has a white tip. ៛ Bielle (talk) 03:09, 12 October 2008 (UTC)


 * I agree. When writing for Wikipedia, one should strive to keep specific cultural references like "candy-corn" out of articles like that. We are read in dozens of countries around the world - most of whom will never have seen or heard of candy-corn.  Most people in the USA know what it is - and what color it typically is - but I doubt whether people from other countries would know.  Sure, you can provide a link to the article candy corn - but it would be much better to use a proper description of the color rather than to send people off on hunts for obscure references like that.  Better still - just put a nice color picture in there. SteveBaker (talk) 03:26, 12 October 2008 (UTC)
 * People who don't know candy corn? My God, man! I don't believe it. I won't believe it!  Plasticup  T / C  05:15, 12 October 2008 (UTC)
 * Well, I've never heard of it. But I wouldn't want to interfere with your deeply held beliefs. Algebraist 09:08, 12 October 2008 (UTC)
 * Looks orange-yellow to me. [By the way, I have no idea what "candy-corn" is. ;-) ] Axl  ¤  [Talk]  11:04, 12 October 2008 (UTC)
 * Candy corn is little multi-colored globs of sugar, usually served at Halloween in the U.S. I've never had a taste for it... --Jayron32. talk . contribs 13:00, 12 October 2008 (UTC)
 * Nobody has tasted it. None have been produced since 1934.  The entire supply at that time has simply been recycled each year. --  k a i n a w &trade; 17:08, 12 October 2008 (UTC)
 * Yeah, every year the entire supply is melted down to make Circus peanuts. Interestingly, every year the entire suply of Circus peanuts is melted down to make candy corns, resulting in a never ending cycle of recycling inedible "candy".  --Jayron32. talk . contribs  18:01, 12 October 2008 (UTC)
 * I think you've all forgotten that the sole purpose of candy corn is to insert two of them - pointy-end-down - between teeth and upper lip for the purpose of scaring little sisters into thinking you have turned into a vampire on all-hallows evening. Subsequent consumption of these objects can only be accidental. SteveBaker (talk) 19:46, 12 October 2008 (UTC)


 * I wonder if Eclecti will eat candy corn, if offered? --Kurt Shaped Box (talk) 22:41, 13 October 2008 (UTC)


 * For what little it's worth, I rather like the stuff. —Tamfang (talk) 01:31, 14 October 2008 (UTC)

I'd never seen, nor heard of 'candy corn' until yesterday. When I saw the term used in the article, I was imagining something like toffee popcorn - or maybe candyfloss. --Kurt Shaped Box (talk) 19:28, 12 October 2008 (UTC)
 * ...which is PRECISELY why we shouldn't use it. SteveBaker (talk) 19:48, 12 October 2008 (UTC)


 * Be better to pick from shades of yellow and link to the chosen shade. Bazza (talk) 14:21, 13 October 2008 (UTC)

Copper(II) Sulfate Crystal
Hello. Are there any catalysts or fancy methods to make a solution of CuSO4 • 5H2O and water crystallize faster, clearer, and with clean cuts? Thanks in advance. --Mayfare (talk) 04:08, 12 October 2008 (UTC)


 * The problem is that speed and quality are exactly competing factors in crystalization. Any method used to make crystals quickly (such as rapidly dropping solution temperature, or "scratching", or adding seed crystals) will cause LOTS of small, imperfect crystals to form.  If you want faster, then create a hot supersaturated solution of CuSO4, and let it cool to below the precipitation temperature.  Drop a small "seed crystal" of CuSO4 • 5H2O into the mixture, and viola, you'll get crystals, but they will likely be small and imperfect.  If you want high quality crystals, you should aim for making them AS SLOW as possible.  You should start with the same hot, supersaturated solution (this is generally made by boiling a saturated solution of CuSO4 until the volume reduces, but there are ABSOLUTELY NO crystals in the solution) and then place it in some insulation, and let it cool VERY SLOWLY.  After several days, crystals should form, and they should be nice and big and well defined.  --Jayron32. talk . contribs  11:38, 12 October 2008 (UTC)

1876 Supplement to Harper's Bazar, No.13 and No. 25
I recently discovered two tapestry patterns from 1876 each are double sided on one side clothing patterns on the other side maybe embordry prints/designs. The patterns and instructions are printed on old newspaper and folded in half twice. The paper is very fragile to handle or measure without causing damage. I want to know more about these documents and how to share them? —Preceding unsigned comment added by Yma99 (talk • contribs) 09:35, 12 October 2008 (UTC)


 * I copied this question from the new users page as how to handle old newspapers is bit beyond a question on how to use Wikipedia.  Sp in ni ng  Spark  09:47, 12 October 2008 (UTC)


 * Perhaps call a museum in your nearest large city? Or go to the local library and ask? Either of these will have people who can direct you to specialist advice. You might check though whether these are already scanned in a web archive somewhere. Franamax (talk) 04:42, 14 October 2008 (UTC)

photographic chemicals
Up to the 1940's photographers knew various chemical formula for making black & white negatives and prints. Where can I find this chemistry? —Preceding unsigned comment added by 122.111.64.194 (talk) 09:58, 12 October 2008 (UTC)


 * A good place to start looking is History of photography and follow the links there. Timeline of photography technology may also link to useful articles.  Sp in ni  ng  Spark  11:06, 12 October 2008 (UTC)


 * Which formula do you want? I have books listing many. Edison (talk) 23:21, 12 October 2008 (UTC)

electron configuration of Barium
Hi is the following electron configuration for I have come up with for the element barium correct?

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2. Thanks. —Preceding unsigned comment added by 139.222.240.110 (talk) 12:43, 12 October 2008 (UTC)


 * Looks right to me. Barium is in period 6, group IIA, which should have the configuration "...6s2" and it doesn't look like you missed any core orbitals either.  --Jayron32. talk . contribs  12:57, 12 October 2008 (UTC)


 * Yeah, that's right. Source: Clicky —Cyclonenim (talk · contribs · email) 13:58, 12 October 2008 (UTC)

thanks :) —Preceding unsigned comment added by 139.222.240.66 (talk) 17:50, 12 October 2008 (UTC)

Using nuclear weapons as a propulsion system for spacecrafts
I'm reading Neal Stephenson's new book Anathem and in it he describes a rather unusual propulsion system for spacetravel (this isn't a big spoiler at all, feel free to read on even if you haven't read the book yet).

The idea is this: a spaceship would have one side on it that is covered by a so-called "pusher plate", which acts as a big shield, capable of withstanding a nuclear blast. A nuclear weapon is deployed on the other side of it and detonated, and thus the spaceship would fly off with enourmous velocity (essentially rocket jumping, but with nuke instead of a rocket and a spaceship instead of a player).

I've thought a little bit about this, and it seems to me that this wouldn't work. The reason a nuclear weapon will blow everything around it to smithereens (like that famous exploding house that we've all seen), is that it has an enourmous shockwave. But space is essentially a vacuum, there's no medium for a shockwave to propagate through. So it wouldn't impart basically any momentum to anything near it. The only thing that would happen (I imagine) is that it releases lots and lots of energy through electromagnetic radiation, which would barbeque any organic material nearby, but it wouldn't actually have a shockwave. I don't know if electromagnetic radiation departs any momentum on the things it hits, but even if it does, it's not all that much, is it?

Look at the sun: the sun is basically a mindnumbingly big nuclear reaction, much much bigger than any nuclear weapon, yet it doesn't "propel" it's satellites to enourmous speeds. The earth isn't flying off into space because of the sun. So why would this system work? 195.58.125.56 (talk) 17:51, 12 October 2008 (UTC)


 * See Project Orion (nuclear propulsion). Its "performance" section explains how they intended to design special bombs such that they'd maximise the kinetic yield of the nuclear explosive, which they'd then impart to the spacecraft itself by collision. -- Finlay McWalter | Talk 17:56, 12 October 2008 (UTC)
 * (e/c) Neal stephenson is just one in a long line of science fiction authors who have used the idea proposed by Stanislaw Ulam in or about the late 1950s. See Nuclear pulse propulsion.--Fuhghettaboutit (talk) 17:58, 12 October 2008 (UTC)


 * Yep - project Orion is famous in Sci.Fi. circles - lots of books have used it. I'd argue that the rather subtle manouvering that's implied would be impossible for such a craft - you've only got an all-or-nothing thrust mechanism.  You can't do a "three second orbital injection burn" with a motor that either kicks you up the backside with 20 megatons or does nothing at all.  But with such a large craft - you'd need something pretty powerful. SteveBaker (talk) 19:39, 12 October 2008 (UTC)
 * If I were building such a craft I would include a conventional rocket engine as well for the subtle stuff. Just use the nukes for simple acceleration. You need to be able to get a safe distance from anything you don't want to blow up/irradiate anyway, which requires some kind of propulsion. --Tango (talk) 20:40, 12 October 2008 (UTC)
 * If you don't mind wasting a bit of ΔV, you can dial down the thrust by delaying the explosions by various amounts, to detonate the bombs further from your ship. --Stephan Schulz (talk) 22:45, 12 October 2008 (UTC)
 * Nah, you only use nukes for intersteller travel. For manuvering you use conventional muntions.  "Three grenades to starboard.  Aye, Captain!".  ;-)  Dragons flight (talk) 22:49, 12 October 2008 (UTC)
 * At least that will improve chances for peaceful first contact with the Minbari. --Stephan Schulz (talk) 22:52, 12 October 2008 (UTC)


 * Just to address the main question in it: it's not the shockwave that pushes the ship. You put in some plastic (basically) and the heat/radiation of the bomb turns it into a very dense plasma which expands/explodes and that pushes things. Basically. --98.217.8.46 (talk) 02:14, 13 October 2008 (UTC)

Also interesting is Nuclear salt-water rocket. Essentially a continuously exploding nuclear pulse propulsion rocket. ScienceApe (talk) 00:13, 13 October 2008 (UTC)
 * Wow! That's a cool idea. I like it! SteveBaker (talk) 01:37, 13 October 2008 (UTC)

What good an anal probe?
I've just thinking about all those personal accounts of (supposed) abduction and experimentation upon humans by aliens. How much useful data would one actually be able to collect on a human subject by probing its anus? Can anyone think of what it is that the prober might actually be trying to discover about the probee by doing this?

The taking of skin, blood, sperm and tooth samples at least kinda makes sense from a 'research into the species' viewpoint. --Kurt Shaped Box (talk) 19:24, 12 October 2008 (UTC)


 * It's a particularly unpleasant and degrading experience which elicits sympathy from those the abductee tells about it. --Tango (talk) 19:35, 12 October 2008 (UTC)


 * Apparently aliens are fascinated by cows (e.g. cattle mutilation). Perhaps they are looking for evidence of beef consumption?  Dragons flight (talk) 19:50, 12 October 2008 (UTC)


 * Temperature and eating habits come to mind. —Cyclonenim (talk · contribs · email) 20:53, 12 October 2008 (UTC)


 * As does inspiring the fear of invasion. Julia Rossi (talk) 21:44, 12 October 2008 (UTC)


 * I think they are looking for our brains - they must be in an out-of-the-way place as we only occassionaly use them.  Sp in ni ng  Spark  22:20, 12 October 2008 (UTC)


 * If this were truly happening - an alien wanting to do a "non-invasive" investigation would of course start off by checking and sampling material from every obvious external orifice. SteveBaker (talk) 22:28, 12 October 2008 (UTC)


 * Though can cross the galaxy but somehow they haven't invented x-rays, cat scans, or MRIs? Dragons flight (talk) 22:44, 12 October 2008 (UTC)
 * Sampling...extracting fluids and solids. SteveBaker (talk) 23:50, 12 October 2008 (UTC)


 * They have. But they have a huge co-pay. - Nunh-huh 22:57, 12 October 2008 (UTC)
 * You know, I would consider someone sticking something up my rear end to quite invasive... --Tango (talk) 23:01, 12 October 2008 (UTC)


 * Fair point, Steve - but I don't recall reading many (any?) accounts of oral probing in the abduction accounts. --Kurt Shaped Box (talk) 23:33, 12 October 2008 (UTC)
 * Observer bias. The people who were asked nicely to say "Ahhhh" and got a lollipop at the end of the probing didn't complain as much as the ones who suffered less dignified forms of testing.  :-) SteveBaker (talk) 23:50, 12 October 2008 (UTC)
 * I forget the poet and the poem, but it was on the lines of "Aliens came from another planet/and studied humans/and decided they were a means/for the production/of shit". Any outside observer studying our hygiene habits, and the attention paid by humans to the emanations of dogs (picking up in bags and carrying it around fer gawdz sake), would surely conclude that there must be something very important up there and feel the need to investigate. Franamax (talk) 04:35, 14 October 2008 (UTC)


 * the whole anal probe thing is a front, they only do it to distract the abductee from what they're really doing, and make stories of their experiences sound even more ridiculous when they're returned to Earth. What they really do is something much, much more sinister. --86.135.181.146 (talk) 14:42, 16 October 2008 (UTC)

how much gas?
How much gas would an average human be able to pass in his or her lifetime? ("Would" because normally we don't try to maximize this. I mean if they were to eat a lot of beans all their life -- nothing chemical/artifical). —Preceding unsigned comment added by 82.120.232.170 (talk) 21:41, 12 October 2008 (UTC)


 * Well, the Mythbusters measured between 3 and 10 'gas passing incidents' per day on a normal diet - with a typical volume of around 13ml per 'incident'. Let's pick 5 per day as an average.  Over a 70 year lifespan - that's 70x365x5x13ml = 1600 liters - which you could visualize as being about the volume of a good-sized house .  On a 'bean-intensive diet, the Mythbusters registered 22 incidents per day - with a peak volume of 170ml in one hour - so we should say that about five times the 'normal' amount is probably about the maximum.  But there are HUGE error bars on those numbers.  I'd believe 5 times more or 5 times less than that 1600l number. SteveBaker (talk) 22:46, 12 October 2008 (UTC)


 * 1 cubic meter is exactly 1000 liters, so 1600 liters is 1.6 cubic meters. That's about the volume of a 1.2 m x 1.2 m x 1.2 cube.  --99.237.96.81 (talk) 22:56, 12 October 2008 (UTC)


 * Er - yeah. Sorry - I slipped a zero or three there!  Wow...that's *NOTHING*. SteveBaker (talk) 23:52, 12 October 2008 (UTC)


 * Steve, we're allowed to screw up like that - you're not! ;) hydnjo talk 00:59, 13 October 2008 (UTC)


 * According to Britannica, a lactase deficient person will produce (or rather, the persons gut bacteria will produce) 500ml to 1000ml of gas from one glass of milk. So if you really wanted to go for it and do record breaking stuff, ten glasses per day would not be too challenging and would yield (for Steve's 70 years) 70x365x10x750ml = 191,625 litres.  Which is a bit more house sized.  Sp in ni  ng  Spark  23:39, 12 October 2008 (UTC)