Wikipedia:Reference desk/Archives/Science/2010 June 5

= June 5 =

Reduction potential for nitrate
What is the reduction potential for this reaction: 2 NO3- + 12 H+ + 10 e- ←→ N2 + 6 H2O Thank you. --Chemicalinterest (talk) 00:28, 5 June 2010 (UTC)
 * from
 * NO3- > NO 0.957
 * NO > N2O 1.591
 * N2O > N2 1.766
 * I think you can just add those ~2.2V ? Maybe not - different number of N atoms... Different number of electrons transfered in each reaction.
 * It's {(0.957x3)+(1.591)+(1.766)}/5 (reason for that formula at Standard_electrode_potential 87.102.32.39 (talk) 01:20, 5 June 2010 (UTC)
 * About 1.25V also see here 87.102.32.39 (talk) 01:39, 5 June 2010 (UTC)
 * Thanks for your help. (BTW, when you type chemical formulas, it is recommended to put subscripts and superscripts around the appropriate figures, such as NO3 -, making NO3-) I don't think it is 5V. Even F2 gas is +2.87 or +3.01. Many times going from step to step is harder than "taking all the steps". Hypochlorite, chlorite, chlorate, perchlorate is an example. Each one has an oxidation potential of about +1.5V to the next one, yet perchlorates are not supremely reactive because the steps are not added up (they are actually the least reactive). +1.25V seems right, a little higher than the reduction potential (+1.23) for oxygen in an acidic environment. --Chemicalinterest (talk) 11:07, 5 June 2010 (UTC)
 * Yes the EMF is an average - that comes from the energies of reaction being additive, but the actual EMF's are measured 'per electron transfered' - thus energy change = electrons x voltage
 * eg for NO3- >> NO (change from V state to II state)
 * eg NO3- + 4H+ + 3e >> NO + 2H2O + NO (3 electrons)
 * ..the energy change is three times that what it would be if only one electron had been transfered
 * this equation in fact :ΔGcell = −nFEcell where F is Faraday constant
 * It's actually similar at a simple level to the formala for potential energy of a charged particle in an electrostatic potential E=QV (or as written in Electrostatic_potential UE = qV ) 87.102.43.94 (talk) 11:41, 5 June 2010 (UTC)

Who first hypothesized/discovered/elucidated gluconeogenesis?
Who first hypothesized or discovered or elucidated gluconeogenesis? Thank you. --Rajah (talk) 00:54, 5 June 2010 (UTC)
 * this link mentions some key people (last 2 paragraphs) 87.102.32.39 (talk) 03:17, 5 June 2010 (UTC)
 * Thanks, but that's about glyceroneogenesis, which is a subset of gluconeogenesis. The conversion of pyruvate to glucose would be the major component of gluconeogenesis. --Rajah (talk) 06:52, 5 June 2010 (UTC)
 * Sorry, I was working quite late - didn't even notice at the time. Please accept my apologies.87.102.32.39 (talk) 10:51, 5 June 2010 (UTC)
 * No problem. Actually, your mention of it spurred the creation of the article on glyceroneogenesis! --Rajah (talk) 17:02, 7 June 2010 (UTC)
 * This is not a topic I know anything about, but just for the hell of it I trotted out my Googling skills, and found that the fundamental work on the chemistry was done by A. I. Ringer and colleagues in a series of papers in the Journal of Biological Chemistry in 1913 and the following few years. The physiological background was worked out over the previous few decades, largely in German publications.  The state of affairs as of 1913 is reviewed in this paper. Looie496 (talk) 22:33, 5 June 2010 (UTC)
 * Awesome, thanks! Yeah, tha'ts probably the first mention in English. And a European would've probably been the first to hypothesize it under a different name. --Rajah (talk) 17:02, 7 June 2010 (UTC)

Brass
Alloys of Copper and Zinc create a how to hop metal brass.lam not work on this solution and HCl solution H2SO4 ? —Preceding unsigned comment added by I love chemistry (talk • contribs) 04:02, 5 June 2010 (UTC)
 * Could you please rephrase your question, I don't really get what you're trying to do. 67.170.215.166 (talk) 04:30, 5 June 2010 (UTC)
 * Sounds like "I love chemistry" is asking how to separate Cu and Zn in brass using HCl and H2SO4, which sounds a little like a homework problem, though I won't assume, but I recommend checking reduction potentials and noting if any salts will precipitate. SamuelRiv (talk) 05:41, 5 June 2010 (UTC)
 * This is original research. I tried dissolving brass in hydrochloric acid but it is very difficult too, it is a rather noble alloy. Do not expect the zinc to come fizzling out, leaving a framework of copper behind. --Chemicalinterest (talk) 11:08, 5 June 2010 (UTC)
 * See galvanic series; you can see that it is rather noble (closer to the top than say, aluminum, iron)--Chemicalinterest (talk) 11:15, 5 June 2010 (UTC)
 * More so than either copper or zinc - I don't really understand why.87.102.43.94 (talk) 11:27, 5 June 2010 (UTC)
 * If the aim is an analysis of Cu and Zn in brass then this link gives the standard proceedure or this 87.102.43.94 (talk) 11:25, 5 June 2010 (UTC)


 * If you want to know how to make brass there is an interesting but old manual here eg "Put 4 1/2 lbs. of copper into a crucible, expose it to heat in a furnace, and when perfectly fused add 1 1/2 lbs. of zinc. The metals will combine, forming that generally used alloy called brass." there are recipes for other brasses too. And a more up to date list at Brass ? 87.102.43.94 (talk) 12:09, 5 June 2010 (UTC)

Asa Gray and John Edward Gray
I'm planning on editing a few articles on nineteenth century biology and I've come across a question I can't answer. Is there a relationship between Asa Gray and John Edward Gray? I know one is British and the other American, but they both seem to be biologists during the same time period. I'm most interested in if they are related biologically and if they there are any primary sources mentioning the relatedness of both of them. Thanks a bunches :) Peter Napkin Dance Party (talk) 07:27, 5 June 2010 (UTC)
 * The WP:RD/H may be a better place. --Chemicalinterest (talk) 11:09, 5 June 2010 (UTC)
 * Here'll do. It's not looking very likely, or at least not in any meaningful span of generations. AG is described as being "of Scotch-Irish descent" whilst JEG's grandfather was a London seedsman who died without inheritance . I'd question how much migration of "Scotch-Irish" into the London area was going on in the mid or early C18 ... not very much. All in all, has the feel of a coincidence of surnames and nothing more. --Tagishsimon (talk) 13:02, 5 June 2010 (UTC)

Brass (30% Zinc and 70% Copper)
How to Brass (alloy of 30% Zinc and Copper 70%) not destroyed in the dense environment axid Chlohydric, axid in solution and concentrated sulfuric (H2SO4)and water Amonia (NH3). No surface coating of the alloy, only add other elements to increase resistance axid, but no change yellow color of the alloy elements nay.Neu you know is right, then please just help with!--I love chemistry (talk) 13:40, 5 June 2010 (UTC)
 * Your question does not seem very clear. Do you want to know why acids don't attack brass? --Chemicalinterest (talk) 13:41, 5 June 2010 (UTC)


 * If that is your question, then my explanation is that: On the surface, there is a mixture of copper and zinc. The small amount of zinc corrodes, leaving only copper on the surface (explains why few bubbles appear on surface when immersed in acid). The copper is resistant to acid attack (see standard reduction potential for explanation of oxidation and reduction, also see redox), which prevents further corrosion. Brass is also resistant to corrosion by the oxidizing properties of copper salts. Again, the small amount of zinc on the surface dissolves, plating the brass with a durable coating of copper metal.
 * In short, when the zinc dissolves, the brass is essentially a copper-coated strip of brass. --Chemicalinterest (talk) 13:48, 5 June 2010 (UTC)
 * Actually in ammonia the copper actually dissolves. In air, copper forms a protective coating of copper(II) oxide. That dissolves in ammonia to form a complex similar to tetramminecopper(II) sulfate. A new coating forms and dissolves, eating away the copper. This happens very slowly though. It also happens in acid, albeit very very slowly. --Chemicalinterest (talk) 14:10, 5 June 2010 (UTC)
 * If you wanna dissolve brass, you could stick it in nitric acid, and that will dissolve it easily. (Getting the nitric acid might be hard, though -- it's a restricted chemical because it can be used to make bombs.)  FWiW 67.170.215.166 (talk) 01:42, 6 June 2010 (UTC)
 * Simpler way; mix 3% (household) hydrogen peroxide and household muriatic acid in about a 1:1 ratio. That should dissolve brass, the H2O2 functioning as an oxidizer and the HCl dissolving the oxide produced so the peroxide can continue oxidizing the metal. --Chemicalinterest (talk) 12:05, 6 June 2010 (UTC)
 * It does not react that way. Acids stabilize H2O2. --Chemicalinterest (talk) 00:32, 10 June 2010 (UTC)
 * This might also be a good way to make a binary chemical weapon: H2O2 + 2HCl → 2H2O + Cl2. Don't try this at home (at any rate, not unless you do this in a fume hood and while wearing a gas mask).  And if you do get the results that I've predicted, Mr./Ms. I-Love-Chemistry, don't blame me. 67.170.215.166 (talk) 00:51, 7 June 2010 (UTC)
 * Chemicalinterest, didn't your chemistry teacher tell you not to mix halides with strong oxidizers? 67.170.215.166 (talk) 01:09, 7 June 2010 (UTC)

The simple answer to your question is that an alloy doesn't react in the same way as the metals that make it up. You can see this very well with stainless steel, which is mostly iron but is much more resistant to oxidation. There is a huge amount of research as to which alloys have different properties and why, and I can't summarize it all here; there are different answers for different alloys, and it's a specialized area of research. Physchim62 (talk) 14:56, 7 June 2010 (UTC) I leave it as an exercize for the readers why the "binary chemical weapon" wouldn't work. Physchim62 (talk) 14:56, 7 June 2010 (UTC)
 * Acid stabilizes hydrogen peroxide so it does not decompose. Also the Cl- ion is resistant to oxidation by the O22- ion. --Chemicalinterest (talk) 00:33, 10 June 2010 (UTC)

Information on Planting lilies in green house
Dear sir I am asking for information about planting lilies in green house Spatially fertilizer in ( first – medal – end ) life I am from medal est. ( UAE ) & I will planting on 1st October  thank you hamid —Preceding unsigned comment added by 94.59.56.184 (talk) 13:52, 5 June 2010 (UTC)
 * 1) first steps in soil ( compost & per light )
 * 2) soil ( EC & PH )
 * 3) fertilizer program ( 2 weeks 2 – 1 – 1 & 6 weeks 1 – 1 – 1 )

Hi Hamid, we don't respond to queries by email so I've removed your address. Brammers (talk/c) 18:39, 5 June 2010 (UTC)


 * You question does not say which type of lily you are going to grow. You can see from the article that there are many species and some require special conditions to succeed. Some lilies require deeper planting because they develop roots from the stems, others need a deep soil with a 'woodland' shade. Of course many will grow in a nice soil with compost, some slow-release fertilizer and regular watering. My experience with lilies is that you don't need a complicated watering/fertilizing programme. If you are going to grow them commercially then you will need specialised information. Richard Avery (talk) 07:32, 6 June 2010 (UTC)

Deepwater Horizon valves
Hi. Could a piston valve assist in one of the procedues used to cap the flow of oil or to redirect it into a ship? Thanks. ~ A H  1 (TCU) 14:38, 5 June 2010 (UTC)
 * A Piston valve could indeed help - in fact the automatic shutoff valves that failed (the Blowout preventers) causing the problem are (or can be) a type (or variation of) of piston valve (in that the closing motion is linear).87.102.43.94 (talk) 15:05, 5 June 2010 (UTC)
 * A Gate valve has some similarities in design and would be another good choice for closing of a wide pipe.87.102.43.94 (talk) 15:13, 5 June 2010 (UTC)
 * Has anybody suggested this idea to BP? ~ A H  1 (TCU) 15:22, 5 June 2010 (UTC)
 * They've been cutting through the pipe to get a neat end on it - I would expect that their next step is to fit such a valve. 87.102.43.94 (talk) 15:27, 5 June 2010 (UTC)
 * Update: our folks have fitted a new BOP just the other day, but we're keeping it partly open for now to keep it from getting jammed with clathrates. Right now only about 1/3 of the oil is being captured -- we'll be screwing it down to about 90% capture over the next few days, or to as low a flow rate as clathrate formation permits -- but we'll have to keep it open a crack until the relief well is completed. 67.170.215.166 (talk) 01:48, 6 June 2010 (UTC)
 * ok I'll bite.. if it gets jammed with clathrates does that not stop the oil flow - is that not a good thing?77.86.124.76 (talk) 14:59, 6 June 2010 (UTC)
 * You're wrong, 77 IP -- right now, the valve package is set up to divert part of the oil to a recovery ship, thus keeping the pressure down; if the thing gets clogged up with clathrates, it'll block that diversion and cause a pressure rise that could make the whole setup blow out again. 67.170.215.166 (talk) 00:58, 7 June 2010 (UTC)
 * Clathrates, as in clathrate hydrate and methane clathrate? Could that release greenhouse gases into the atmosphere? ~ A H  1 (TCU) 01:36, 7 June 2010 (UTC)
 * This is not about so-called "greenhouse gases" -- it's about stopping the oil leak from killing all the fish in the Gulf and depriving the fishermen of their source of livelihood. We gotta keep our priorities straight. 67.170.215.166 (talk) 02:17, 8 June 2010 (UTC)

Nature/environment/biotope
Hi there! What's the difference between nature, natural environment and biotope? These three (especially the first two) concepts seem extremely similar but since there are three articles I suppose that there is some kind of difference. Could anyone help me to clarify this? /Natox (talk) 14:51, 5 June 2010 (UTC)


 * Nature and natural environment are almost synonyms. Nature is an older, looser term that refers to anything not man-made; natural environment is a bit more technical (though less technical than ecosystem or biosphere).  Biotope is a particular type of natural environment.  -- Ludwigs 2  15:17, 5 June 2010 (UTC)


 * (edit conflict - very similar answer)
 * Nature has multiple meanings (dictionary) one of which is synonymous (has the same meaning) as "natural enviroment".
 * As for "biotope" it usually refers to a specific type or area of natural enviroment - eg a "tropical biotope" or a "industrial wasteland biotope", it can even refer to small areas such as the types of biotope a bacteria might live in eg "gut biotope", or even "fridge biotope" - the meaning and usage is quite similar in usage to ecosystem, but they are different and do have technically different meanings. ie an ecosystem will have many different biotopes within it - eg tropical rainforest ecosystem contains river biotope, stream biotope, stream bank biotope, leaf litter biotope, tree canopy biotope, mud biotope and many other biotopes.87.102.43.94 (talk) 15:20, 5 June 2010 (UTC)
 * Thank you both for good answers. This raises another question: How come there are two articles, natural environment and nature, if there is hardly any difference? They seem to be on the exact same subject. /Natox (talk) 15:39, 5 June 2010 (UTC)
 * Yes - I think that's a mistake - it looks like they should be (WP:MERGE) merged - at least I can't see any reason for two articles.87.102.43.94 (talk) 15:48, 5 June 2010 (UTC)
 * I've suggested that they be considered for merging.87.102.43.94 (talk) 15:54, 5 June 2010 (UTC)

Energy efficient of distillation
Assuming that any enthalpy change in the process is negligible, can the energy efficiency of distillation be arbitrarily close to 100%? Is there a reason why a certain minimum amount of energy will always be lost (i.e. become unavailable) in the process? --173.49.77.55 (talk) 16:14, 5 June 2010 (UTC)
 * (There needs to be an real valued enthalpy of vaporisation for distillation to be possible)
 * When you say efficient I assume you mean that 100% of the energy supplied to the system is converted into liquid boiling? If so yes it can approach 100% with effective insulation - there will always be a latent heat of the apparatus (ie start up) - ignoring this ie using continuous distillation the figure can approach 100% but not reach it because perfect insulation doesn't exist.
 * However if you say that the liquid for distillation is supplied 'cold' and do not include energy required to raise the T of the liquid (ie specific heat) then this will cause a less than 100% figure in the efficiency figure.87.102.43.94 (talk) 18:50, 5 June 2010 (UTC)
 * I was thinking about water purification by distillation when I asked the question. By negligible enthalpy change, I mean that you can ignore the energy that is inherently required to separate the impurities from the water, such as enthalpy of solvation. To simplify the problem, just consider the case when you're distilling pure water and condensing it back. Some of the energy used to boil the water can be recouped using a heat exchanger, such as a countercurrent heat exchanger. If the process is 100% energy efficient, the effluent water is at exactly the same temperature as the incoming water, and no incremental energy is needed to process an additional unit volume of water. That seems not possible in practice. Hence the question. --173.49.77.55 (talk) 23:46, 5 June 2010 (UTC)
 * I think the issue here is of getting energy to flow one way (from condenser to boiler). I think what you are describing is (the same as) either using the boiling water as condenser fluid or connecting the boiling water and condensor fluid so that they are at the same temperature. Additionally for the 100% efficiency the whole apparatus would have to be insulated -this means that the receiver would be at 100C as well - this would make the whole apparatus in thermal equilibrium - so there would be no net liquid flow.
 * To get net flow the condensor would need to be at a lower temperature than the boiling liquid - for this a heat pump would be needed - I'm not sure whether this heat pump can be 100% efficient.87.102.43.94 (talk) 12:58, 6 June 2010 (UTC)
 * I think theorectically you are right, eg if the whole apparatus is at 100C and a heat pump (see heat pump and related topics) is used to move energy from the reciever to boiler then then theoretical efficiency is infinite.. But it still requires a finite energy input for anything to actually happen. Also what might need to be considered is the need for energy input to prevent a 50:50 distribution of liquid in receiver/boiler coming about be the two being in effective equilibrium.87.102.43.94 (talk) 13:06, 6 June 2010 (UTC)


 * start again simple explanation - The idea of the distillation is to transfer a liquid from A to B, both at the same temperature. The energy required to do this is 0. But to actually get anything to happen there needs to be a non-zero energy difference between the two states (start state and finish state) - a non zero amount of energy will need to be supplied constantly to maintaine an energy differential (A>B) while the process is proceeding.87.102.43.94 (talk) 13:58, 6 June 2010 (UTC)
 * The energy required can approach zero, but when it is zero nothing happens.87.102.43.94 (talk) 14:00, 6 June 2010 (UTC)
 * If the purpose of the destillation is to desalinate water, you must take into account that the vapor pressure of salt water is lower than the vapor pressure of sweet water, so without doing work on the system the process will go in the wrong direction. The salt water must be warmer in order to increase to vapor pressure above that of sweet water. Bo Jacoby (talk) 21:29, 6 June 2010 (UTC).

Beer question
Why does beer taste better out of a glass bottle than a can? I'm mainly talking about bitters and ales here, I don't tend to drink many macrobrew lagers. 188.221.55.165 (talk) 17:48, 5 June 2010 (UTC)
 * Glass doesn't taint the liquid inside it. I'm sure someone will contradict me, but even if cans are lined with plastic, you can taste the tin, which must mean it has tainted the contents. Also you can't put real ale into a can because it will have to be pasteurised during the canning process, which means it loses its real ale status. Filtering and pasteurising beer will also alter the taste. You can get real ale in a bottle, and you can have filtered and pasteurised ale in a bottle. Personally (and I will be drummed out of CAMRA for saying this) I will gladly drink a bottle of beer even if it's not real ale, because the quality can be almost guaranteed. --TammyMoet (talk) 19:17, 5 June 2010 (UTC)
 * For one thing, it's often cheap beers that are distributed in cans. To make a fair comparison, you'd need to look at the same brand of beer in both cans and bottles.  From a manufacturing standpoint, canned beers are clearly superior: it's easy to seal a can, and no light can get in.  I would suspect that both the glass and can are relatively neutral in regards to taste, and that it's much more likely to be the feel of glass vs. metal that makes a difference in terms of enjoyment (and note that beer cans are aluminum, not tin, as TammyMoet incorrectly asserts).  Many of the people online suggest that beer should always be drunk from a (glass) cup, whether it comes in a can or a bottle.  See also  for one among many opinions on the matter.  Googling "beer can vs bottle" will bring up tons of other opinions on the matter. Buddy431 (talk) 22:15, 5 June 2010 (UTC)
 * 'Tin' is used as a synonym for 'can' in the UK. I doubt Tammy is asserting anything about the composition of the can/tin, only that it can be tasted. And indeed it can, although I suspect that is mostly the smell from the metal on top, particularly the exposed surface you've just created in opening it. I wonder if the same effect is evident when the beer is decanted before drinking. 86.164.69.239 (talk) 22:48, 5 June 2010 (UTC)
 * Agreed to the small comment above; beer in a can is different to beer in a bottle. Try Budweiser in a beer can and bottle, you'll notice a slight difference. The tin taints the beer slightly. Regards, --— Cyclonenim | Chat 23:29, 5 June 2010 (UTC)
 * BTW, there is no tin in tin cans. They are made of steel or aluminum. And for a proper test pour the beer into a glass before drinking it. Ariel. (talk) 03:37, 6 June 2010 (UTC)
 * To clarify, I wasn't asserting cans were made out of tin, but in the UK and associated countries, cans are known as "tins". When an Australian refers to a "tinnie", she is referring to a can of beer. --TammyMoet (talk) 08:15, 6 June 2010 (UTC)
 * The UK/Aussie usage is based on the fact that cans were originally lined with tin, and were called tin cans. Often, the "can" was just dropped, and hence the popular usage of just calling any metal container a "tin". --Phil Holmes (talk) 11:54, 6 June 2010 (UTC)
 * Not all tumblers are made of glass; some are made of plastic. -- Wavelength (talk) 15:21, 7 June 2010 (UTC)
 * The OP needs to first test the assumption by doing a blind taste test among several friends. Its an easy thing to do: Find friends that claim they can tell the difference between bottled and canned beer, obtain cans and bottles of the same brand, then pour each into identical glasses, and see who can tell the difference.  -- Jayron  32  03:14, 7 June 2010 (UTC)
 * I always assumed that it was actually DRINKING it out of the can that made the difference, if you poured it into a glass it would taste the same as the stuff from a bottle... Also, wouldn't a can be similar to the kegs that pubs use? I don't know of anyone complaining that beer from a tap tasted "tinny", i thought keg beer was sort of the "gold standard" as long as the pub cleans and maintains their pipework. Vespine (talk) 06:28, 7 June 2010 (UTC)
 * The "gold standard" is real ale out of a wooden barrel! Keg beer is chilled, filtered and pasteurised to remove anything that could possibly give rise to any taste! Keg beer does indeed taste tinny. (Sorry I know I've just got on a soapbox, but a statement such as Vespine made deserve correction.)--TammyMoet (talk) 15:11, 7 June 2010 (UTC)
 * You don't get "tinny" kegs, but you do get dirty ones! Even worse. Regards, --— Cyclonenim | Chat 23:10, 7 June 2010 (UTC)
 * Right sorry i should have qualified, i am a heathen when it comes to beer! I avoid those ultra filtered beers and i drink mostly bottled brewed ales, coopers pale ale is my favorite, but I am FAR from a connoisseur. Having said that, i have never drunk, or even heard of anyone ever drinking beer from a wooden beer barrel! If you're going for a pint of Guiness, you go to the pub to get it from the tap (hence keg, i'm guessing), because that's where it's the best, is how I understood it, if the alternative is in a can or bottle. Not even the specialist microbreweries I have tried have beer in wooden barrels, so sorry but i have no idea what you're talking about there lol, you must be a bigger beer snob then anyone I've met, no offense. ;) Vespine (talk) 03:54, 8 June 2010 (UTC)

Vegetable cooking oils - two groups of questions
I never fry food but I do drizzel pasta with a small amount of cold oil. Questions 1) Trans-fat in oil. This http://www.nal.usda.gov/fnic/foodcomp/search/index.html says that canola/rapeseed oil is 0.395% trans-fat, and sunflower is 0.219% trans-fat. It does not give any figures for the other oils I have looked up. How or why is the trans-fat in there? Where can I find reliable figures for the amount of trans-fat in other vegetable oils?

Question 2). I have just bought a litre of "vegetable oil" from a supermarket in the UK. What is it likely to be, more specifically? Thanks 92.24.182.48 (talk) 18:41, 5 June 2010 (UTC)


 * (2) It's likely to be rape oil. 213.122.16.179 (talk) 19:28, 5 June 2010 (UTC)
 * agree - there's a list at Cooking_oil some of which are not vegetable, some of which are too flavoured to be used, but quite a few can and are used in a vegatable oil.
 * There's a more specific list [] it's quite likely to be a mixture as well.87.102.43.94 (talk) 20:26, 5 June 2010 (UTC)
 * Note that Canola oil is merely a type of rape oil. I think that "vegetable oil" is likely to be a mixture consisting of whatever's cheapest/easiest to obtain at the time of manufacture. Buddy431 (talk) 22:08, 5 June 2010 (UTC)
 * Well, it's not "merely a type" of rapeseed oil &mdash; it's the only type, as far as I know, that's considered fit for human consumption. Rapeseed oil other than Canola has too much erucic acid and is considered toxic (maybe not very toxic, but it's not a foodstuff).  So I kind of doubt it would be any other sort of rapeseed oil.
 * Unless "vegetable oil" in the UK doesn't have to be fit for human consumption? Is it something you'd use for, I don't know, thinning paint or something? --Trovatore (talk) 09:29, 6 June 2010 (UTC)
 * Indeed. In the U.S. "vegetable oil" tends to be primarily soybean oil, or a canola/soybean blend. Pure canola oil (labeled as such) tends to be slightly more expensive. I've also seen "vegetable oil" where the ingredient list was "one or more of soybean, corn or canola oil" (or something similar) implying that the mixture varied based on what was available cheap the day they bottled it. -- 140.142.20.229 (talk) 22:31, 5 June 2010 (UTC)
 * I have two bottles of vegetable oil in my kitchen - one Morrison's own brand, the other Lidl's own brand. Both are labelled as "vegetable oil", and both are 100% rapeseed oil. "Canola" is not a British English word. DuncanHill (talk) 23:47, 6 June 2010 (UTC)


 * (2) About 3 years ago I saw a television documentary about the vegetable oils used in food. They claimed that the cheapest vegetable oil is the palm oil. They also claimed that that was a bad thing because palm oil supposedly is far more likely to cause you diseases in the heart and blood vessels (cardiovascular disease) than any of the other vegetable oils. They even went as far as to point out (and warn against eating) specific food products who are made of palm oil, and who just say "vegetable oil" on the label. --Seren-dipper (talk) 23:10, 6 June 2010 (UTC)
 * Unfortunately I do not have any references to eventual scientific research that would back up the following claim, and I do not remember any of the explanation about why, but I have it from a third hand source (a non scientific worker at a food safety authority) who claims she heard it at her workplace that the healthiest oil to sprinkle on your salad is sunflower seed oil, while the healtiest oil (the one that will turn least harmful) when exposed to high temperatures (i.e. fried or baked) is rape oil. --Seren-dipper (talk) 23:39, 6 June 2010 (UTC)
 * I believe that the consensus now is that canola/rapeseed/rape oil (worldwide naming conventions vary) is the best, due to having high amounts of monounsaturated fats and comparatively high amounts of Omega3. The data from the USDA link above gives - Sunflower oil: saturated 9%, monounsaturated 57%, polyunsaturated 29%, trans 0.2%, Omega3 0.04%. Canola oil: saturated 7%, monounsaturated 63%, polyunsaturated 28%, trans 0.4%, Omega3 9%. Thus sunflower has more 'bad fats' (saturated) and less 'good fats' (monounsaturated, Omega3) than canola oils. The details given in the sunflower oil article are for high oleic (70% and over) sunflower oil, which I am doubtful is what you get when you buy sunflower oil in a supermarket. 92.24.182.231 (talk) 09:51, 7 June 2010 (UTC)
 * That palm oil contains more saturated fats that sunflower oil etc seems to be the health issue eg To complicate things there is an ongoing war in the literature - you find researchers from nigeria etc (places producing palm oil) pushin the health benefits and researchers from places that produce soya, sunflower oil etc saying it's not healthy.77.86.124.76 (talk) 00:15, 7 June 2010 (UTC)
 * Additionally there are different types of palm oil - with quite different constitutions 77.86.124.76 (talk) 00:17, 7 June 2010 (UTC)

Standard Atmosphere...
This is a follow on from the highly informative 'boiling water' disscusion..

i) ' What is a standard 'atmosphere'  ?'

My very rough answer : ' A standard atmosphere, is a precisely determined combination of gases, which given that combination of gases has specfic definable physical properties, and obeys defined relationships between those propeties.'

However, this got me thinking, hence the following question : ii) What factors need to be considered that might make an atmosphere non-standard

To which my initial thoughts where -
 * humidity (ie. 'humid' vs dry atmosphere) - and the 'liquid' component need not be water of course ;)
 * density of gas present.
 * liquid in proximity.
 * 'dust'
 * ionisation ?

Any thoughts from the Desk contributors? Sfan00 IMG (talk) 20:21, 5 June 2010 (UTC)
 * For physical measurements of bp the only factor that seems to be considered is pressure. see Standard conditions for temperature and pressure also Atmospheric_pressure and Atmosphere (unit) (some duplication of information)
 * As to definining what "standard air" is there's some links at Standard atmosphere, both U.S. Standard Atmosphere and International Standard Atmosphere are relevant.
 * In fact "one atmosphere" has been defined as both 100000Pa and 101325Pa (see first link)
 * The IUPAC doesn't seem to specify any other conditions other than pressure... There's definately at least two areas of definition - one for physics and another for atmospheric science.87.102.43.94 (talk) 20:38, 5 June 2010 (UTC)
 * The term I recall from high-school chemistry is not standard atmosphere (an atmosphere is a unit of pressure; no need for the standard), but standard temperature and pressure, abbreviated STP. If I recall correctly, STP was 25 degrees C and one atmosphere.  Whereas my dad's chemistry books all seemed to refer things to 20 degrees C.  I think I prefer that way.  I find 25 Celsius (77 Fahrenheit) to be a little warm. -Trovatore (talk) 20:31, 6 June 2010 (UTC)

tobacco
during some wars they would drink pinecons because of coffee shortages. what did they smoke when there were tobacco shortages. —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 21:16, 5 June 2010 (UTC)


 * According to our (fairly obscure) article Military_Administration_in_Belgium_and_North_France, sunflowers and jerusalem artichokes were used in the 40s. Nicotine, however, isn't present in either of those, so they would probably be rather unsatisfying. I tried to dig around on Google but couldn't find anything. When ersatz products weren't needed, cigarettes were frequently rationed. The Imperial War Museum has a picture of a tobacco tin containing tobacco substitute from the end of the first world war, although it doesn't describe its composition. Brammers (talk/c) 22:41, 5 June 2010 (UTC)


 * Hmmm. This rings a bell. I BELIEVE that there were certain plants (though I don't remember what they are) which would be -mixed- with tobacco, even in the smallest quantities. So you could have a cigarette with a small about of tobacco, and something else to bulk it out. I guess this gives you a little bit of the taste and nicotine. Hmmmm. Smoking Newton   (MESSAGE ME)  00:59, 6 June 2010 (UTC)


 * A chap I knew who was in the navy in WWII said they smoked tea leaves when the tobacco ran out on board ship. He also said that this wasn't "very nice" but it was all they had.  He told me that tea was always in abundance.--TrogWoolley (talk) 14:12, 6 June 2010 (UTC)


 * In the Second World War, British forces were issued with "Victory V" cigarettes. They were generally believed (because of their distinctive taste) to be made from a camel by-product. Some links here. DuncanHill (talk) 14:23, 6 June 2010 (UTC)