Wikipedia:Reference desk/Archives/Science/2010 December 3

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December 3

Drinking from a lake

Whenever I watch survival shows on Discovery Channel, the hosts always say the water from lakes and creeks needs to be boiled before I drink it. So why don't animals drinking from the same water source get sick? Hemoroid Agastordoff (talk) 00:10, 3 December 2010 (UTC)

Animal immune systems will develop a resistance to the microbes they commonly encounter in their local water. In mammals, that resistance can also be partially passed to young animals by breastfeeding, which helps protect the young. In many cases, the human immune system would also develop a tolerance after prolonged exposure, but the first few times you tried the local water there is a chance you could get very sick. Water-borne pests are still a significant cause of death in some parts of the world. Altogether it is generally safer for humans to boil water they find outdoors. Dragons flight (talk) 00:17, 3 December 2010 (UTC)

Some of those "pests" can be severe/lethal. For example, Naegleria fowleri, Entamoeba histolytica, Hepatitis A, and Hepatitis E (20% mortality in pregnant women). Here's a recent real-world example. -- Scray (talk) 01:36, 3 December 2010 (UTC)

In developed countries, the chances of getting sick from drinking from a lake or creek are actually pretty low, unless it contains raw human sewage. Paranoia about this has reached such a level nowadays that backpackers often feel compelled to treat water from even the most pristine mountain streams, which I think is ridiculous. Looie496 (talk) 06:19, 3 December 2010 (UTC)

Well, the chance of giardiasis is pretty low, but it's nasty enough (even though rarely lethal) that it's understandable people don't want to take a chance. I understand the treatment is about as nasty as the disease itself, so that's a double-whammy. If you get a ceramic filter and pump it through, it changes the taste very little. --Trovatore (talk) 06:51, 3 December 2010 (UTC)

Add to the list Pfiesteria, which while rare, can be particularly nasty. --Jayron32 07:02, 3 December 2010 (UTC)

Um, no, I would not add Pfiesteria to the list of human pathogens in fresh water, since it is not a human pathogen based on current understanding. If you have a current, reliable source to the contrary, please share. -- Scray (talk) 12:20, 3 December 2010 (UTC)

Not saying that people should go out and do this, but when I was in northern Minnesota a few years back, I drank water straight out of the lakes for a week with no ill effects of any kind. Googlemeister (talk) 14:31, 3 December 2010 (UTC)

I've seen wildly varying advice on this, and I agree that it would be highly desirable to have a better answer for this - preferably not "yes" or "no" but a realistic estimate of the actual risks for water from various sources. Wnt (talk) 17:29, 3 December 2010 (UTC)

I (and others) have provided links to very real diseases, and many of those articles specifically cite untreated fresh water as a source of those infections. Those articles also indicate the risk varies by season, geographic region, regional flooding, proximity of livestock, and other factors. No single "rate" would be a good estimate of a specific situation. -- Scray (talk) 03:58, 4 December 2010 (UTC)

Also, animals in the wild have a much higher mortality rate than those in captivity precisely because of these kinds of risks. --Sean 18:45, 3 December 2010 (UTC)

Crocodiles, cougars, wolfs, bears and lions are more of a risk for animals in the wild, the hard winters might also add to the risk. Most Americans will avoid the not-chlorinated fresh water because they are not used to the taste. I drank water in Baltimore and I would avoid to swim in a pool chlorinated with that amount of chlorine, but the US colleagues said they do tast the chlorine.--19:01, 3 December 2010 (UTC)

Better than ice bottles

I heard from a friend that using antifreeze bottles rather than ice bottles can greatly increase the cooling effect in a picnic cooler. The basic idea is that by keeping the water liquid down to -18 °C, you will keep its heat capacity high, because water has about double the heat capacity of ice. This effectively doubles the power of the bottles(until it they reach 0 °C anyway).

My question is, does water with antifreeze in it have the same or similar heat capacity as plain water? How much antifreeze does it take to keep water liquid down to about -18 °C anyway? I think automotive antifreeze is good enough to -40 °C, so it can be diluted if antifreeze doesnt have as much heat capacity as water.

Oh by the way, for those who really like to get technical, I know the densities are all different so lets just assume we are dealing with volumetric heat capacity. I'm gonna use a four 2L Coke bottles in a big cooler and weight savings are insignificant. Roberto75780 (talk) 00:50, 3 December 2010 (UTC)

I don't this makes sense. The heat of fusion of water means that when ice melts it absorbs heat equivalent to what you'd need to raise its temperature by over 70°C. If you start with chilled liquid you lose that benefit. --Anonymous, 01:03 UTC, December 3, 2010.

Yes, I thought of that, too. If your freezer goes down to -18°C or -40°C, then you could freeze that and possibly get some benefit relative to water, but most freezers won't. I don't recommend putting antifreeze anywhere near food, though, since it may leak and is poisonous. Salt-water would be a safer alternative, is less expensive, and also lowers the freezing point of water down to -18°C or below. And yes, salt-water is poisonous in large quantities, but you couldn't possibly choke down enough food drenched in salt-water to harm you. StuRat (talk) 03:33, 3 December 2010 (UTC)

Why would you have a benefit? The specific heat of propylene glycol is 2.507 j/gK vs. 4.18 j/gK for water. I couldn't find the heat of fusion of propylene glycol but I can't imagine it's more than water. Water is a very far outlier as far as heat capacity goes, I don't know of any material that beats it. According to Specific heat#Table of specific heat capacities water is tops on volume, and close to the top by mass. Ariel. (talk) 05:16, 3 December 2010 (UTC)

Because most of the benefit of ice is in the heat it takes to melt it, you get a fairly quick increase in temp up to the melting point, then it languishes there for a long time, then once it melts you get another fairly quick raise in temp to the ambient temperature. Thus, the benefit of either antifreeze or saltwater is that, if you can get it cold enough to freeze, it should hover at that lower temp while melting, and thus provide more cooling during that period. StuRat (talk) 04:55, 4 December 2010 (UTC)

There were (and may still be) these freezer bricks called "Blue Ice" which I think contained antifreeze such that although they did freeze in your freezer, they froze colder, or something. (I've still got several of 'em, but most of the ones I used to have developed leaks, which made for a real mess.) We don't have an article, but our Blue ice disambiguation page does contain a redlink for "Blue Ice (ice pack), an artificial ice pack filled with propylene glycol manufactured by Rubbermaid". —Steve Summit (talk) 02:26, 3 December 2010 (UTC)

The don't freeze colder. As best they just remain flexible allowing you to mold them to fit around the item. Ariel. (talk) 05:16, 3 December 2010 (UTC)

Not at all! the heat of fusion (heat absorbed during melting) itself for water is equal to the heat absorbed in a 79 °C temperature change! Hoever, if you put just enough antifreeze so that the ice would still freeze, but at a lower temperature (typical freezer is like -18C) you could benifet a little. keep in mind though, that the antifreeze ingredient takes up significant portion of the solution and it has a lower heat capacity and heat of fusion than water. so you wont bennifet much at all. what you should do, is just add a little salt. its cheaper, not poisonous, and it doesnt take up much space (infact, adding salt doesnt significantly affect the volume of the water, believe it or not). even with the salt though, the difference is hardly worth the hassle. see if you can just add more ice! use square bottles instead of round ones. —Preceding unsigned comment added by 209.148.241.197 (talk) 08:51, 3 December 2010 (UTC)

You're the second person who said this - how would they benefit? Just because the water is frozen doesn't mean the specific heats goes away - you can still chill it to -18c, you're just chilling ice instead of water. Ariel. (talk) 09:07, 3 December 2010 (UTC)

The heat capacity of liquid water is 4.18 J/g/K, whereas that for water ice is 2.05 J/g/K. That is, it takes about twice as much heat to raise the temperature of liquid water 1°C than it does to raise the temperature by 1°C of the same amount of water as ice. That's for pure water, though. Additives would change this, though. -- 174.31.199.95 (talk) 17:03, 3 December 2010 (UTC)

The heat capacity of liquid saltwater is a bit less, around 3.99 J/g/K at the salinity of ocean water, but this slight disadvantage versus liquid freshwater is more than made up for by it's huge advantage relative to freshwater ice. So, in the range of temperatures between 0°F and 32°F (-18°C and 0°C), saltwater (liquid) has a much greater thermal capacity than freshwater (ice). Since this is right in the range where we would want the coolant, this is fairly important in choosing. StuRat (talk) 19:10, 5 December 2010 (UTC)

UPS watt, volt-amp question

I got a UPS today (one of many I've had through the years). It is "700 watts" but only "425 volt-amps". A watt is a volt-amp. The voltage is about 120, so why don't these figures match? Is it because the UPS output is a square wave? Bubba73 ^{You talkin' to me?} 05:24, 3 December 2010 (UTC)

The article Volt-ampere explains the difference between volt-amps and watts. They are only equal in DC circuitry. --Jayron32 05:52, 3 December 2010 (UTC)

I think they're the same for resistive AC loads, too, aren't they? See also power factor. —Steve Summit (talk) 05:56, 3 December 2010 (UTC)

True, because the load is constant even if the source is AC. Strictly speaking, though watts and volt-amps are identical through dimensional analysis, they measure slighly different things. The relationship between watts and volt-amps is roughly analagous to the relationship between work and energy. While they are both measured in Joules, they are not identical concepts. --Jayron32 06:01, 3 December 2010 (UTC)

All I meant was that the values could be equal. As you say, they certainly measure different things. —Steve Summit (talk) 06:10, 3 December 2010 (UTC)

In AC circuits the volt-amps can be larger than the watts if there is not unity power factor (resistive load), but I don't understand the 700 watt and 425 voltamp rating. Is 700 watts the output rating or the input (from the mains to the UPS)? Edison (talk) 19:17, 3 December 2010 (UTC)

Whoops - I got it bavckwards, 700va, 425 watts. Bubba73 ^{You talkin' to me?} 04:37, 4 December 2010 (UTC)

Getting a guinea pig to drink from a bottle

Is it possible to accustom a 4-month-old guinea pig to drink from a bottle, or will they only drink from it if trained to do so from a young age? Thank you to anyone who can help. Leptictidium (mt) 07:45, 3 December 2010 (UTC)

its deffinately possible. add salt to the water and they will drink more. check the water level to make sure hes drinking enough before leaving that as his only source of water. and make sure its steady enough so you are not measuring a whole lot of water lost to dripping! 209.148.241.197 (talk) 08:55, 3 December 2010 (UTC)

Salt???? That would do it harm and would not quench its thirst. It would be like humans drinking seawater. If there is no other water available and it finds a drop of water at the bottle, then its going to lick that. I would find out if its customary to use water bottles with them. 92.29.114.35 (talk) 11:27, 3 December 2010 (UTC)

That would all depend on the amount of salt. After all, some salt is essential for life, but they probably already get that amount from their food. Humans tend to get salt from both food and drinks, but usually most from food. StuRat (talk) 04:43, 4 December 2010 (UTC)

Guinea pigs naturally eat food and water without any added salt. Most humans, at the very least in the West, are consuming far too much salt. (There seems to be zero teaching about health in the US of A). 92.24.177.111 (talk) 12:12, 4 December 2010 (UTC)

Yes, people eat too much salt, but that's a direct result of it being deficient in a natural diet, which has led to us craving it wherever we can find it. Similarly, guinea pigs likely crave salt, which is probably why it's the 6th ingredient in this food product for them: [1] (pick "MORE INFORMATION" for the ingredients list). StuRat (talk) 16:31, 4 December 2010 (UTC)

People have evolved to enjoy eating things that were in short supply in the diets in the distant past. That does not mean that its healthy to consume whatever it is abundantly. Poor guinea pigs. 92.15.23.156 (talk) 18:59, 4 December 2010 (UTC)

No, and neither does it mean that we should try to put them on a totally salt-free diet, which would no doubt kill them. StuRat (talk) 19:25, 4 December 2010 (UTC)

There's no danger of that. Even natural unprocessed foods contain small amounts of salt. 92.15.1.139 (talk) 14:26, 5 December 2010 (UTC)

Sorry, but there is a danger of that. Some natural foods contain small amounts of salt, like whole wheat four: [2], and many other contain none at all, like apples: [3]. Meats do tend to be higher in salt, like beef: [4], as do some products from the ocean, like seaweed: [5]. However, a vegetarian diet with no source of food from the sea will tend to be deficient in sodium, unless some salt is added. And, yes, people do tend to add 10 times as much salt as they need to. StuRat (talk) 16:55, 5 December 2010 (UTC)

Guinea pigs do not eat seafood. I recall the true optimum for humans is about 2g of salt a day: the RDA was set at 6g to be an achievable goal rather than the optimum. If you eat any processed foods then you are likely to get more than enough salt without having to add any more. 92.15.31.223 (talk) 18:31, 5 December 2010 (UTC) 92.15.31.223 (talk) 18:25, 5 December 2010 (UTC)

And until the other guinea pigs in the cage start to disappear, I will assume they aren't carnivorous, either. :-) The USRDA of sodium is 2400 mg, or 2.4 grams. But, of course, there's also chlorine in table salt (NaCl), so that would weigh over 14.6 grams. Who has set an RDA of 6 grams ? And, yes, humans who eat any processed foods likely get enough sodium, but how is this related to whether guinea pigs do ? Are we tossing them table scraps ? StuRat (talk) 18:35, 5 December 2010 (UTC)

I thought the UK RDA target for salt was 6g but according to Salt#Recommended_intake its now only 4g. In the linked PDF I recall it says that the optimum is about 2g of salt. As I expect you are aware 1g of sodium is equivalent to about 2.5 g of salt. 92.24.184.218 (talk) 14:09, 6 December 2010 (UTC)

Generally most animals will find their way to a water source when they're thirsty. Water bottles are usually recommended over bowls, as they are more hygienic (provided it's kept clean) and the guinea pig won't be able to soak it's enclosure by taking an impromptu bath. A bottle with a stainless steel ball bearing ("sipper bottle") is not supposed to leak, but they often do, a little. This means that there's usually a drop of water hanging from the end of the tube, which will give the guinea pig a hint. Setting the guinea pig in front of the bottle or vice versa so that it can see there is water there may also be useful. If you have other guinea pigs, it may learn from observing them. Adding salt to the water is not a good idea, and also will not help your guinea pig "discover" the bottle for the first time; however you could smear a little of some food the pig finds tasty on the tip of the bottle to encourage it to drink. If you're concerned that your guinea pig is not taking an adequate amount of water, you should contact your vet for advice. Typical water intake is 10ml per 100g body weight per day. ([6]). --Kateshortforbob _talk 12:11, 3 December 2010 (UTC)

Honestly, call the local pet store, they can probably give you better feedback on this than we can over the phone, for free. 90% of the advice you'll get on this topic here will be related to anecdotes of half-remembered childhood pets. ;-) --Mr.98 (talk) 13:14, 3 December 2010 (UTC)

To teach baby chickens to drink you dunk their beaks in water. Maybe you could do a similar thing where you gently press your critter's snout against the water ball so it gets the idea. --Sean 21:55, 3 December 2010 (UTC)

Purifying Iron

When Iron is extracted from ore, it goes through a process where while highly heated it is exposed to the air and the Carbon impurities react with O2 to form CO2. Why doesn't the iron also react with the oxygen? Chipmunkdavis (talk) 09:33, 3 December 2010 (UTC)

Two reasons, which are related. Carbon reacts stronger with O2 than iron does, so the carbon will burn off first. The second reason is that it's too hot. It's hot enough that it thermolyses the iron oxide back into iron and oxygen - but CO2 is bound too strongly for that temperature to thermolyse it back to carbon (and also the CO2 escapes as a gas). Ariel. (talk) 10:46, 3 December 2010 (UTC)

If it is so hot to thermolyze the iron(III) oxide, why not just heat the iron(III) oxide without the carbon? Is the carbon the stuff making the heat? --Chemicalinterest (talk) 14:08, 3 December 2010 (UTC)

Iron filings or steel wool burn nicely in atmosphere when heated red hot. Don't they refine ore (containing iron oxide) by heating it in an atmosphere without much free oxygen, like a "reducing atmosphere," whatever that is? Perhaps the burning charcoal produces superhot air with products of combustion and little excess oxygen. Early US iron works in the 1700's and early 1800's had big stone furnaces with charcoal in the bottom, and ore above, and the ore was not exposed to excess air, to keep it hot and to avoid basically burning or oxidizing the superheated iron. "Blooms" or lumps of refined iron were then left mixed with slag. William Kelly and Bessemer later came up with the process of heating molten iron and pumping in oxygen to burn off the excess carbon and make steel. Edison (talk) 19:14, 3 December 2010 (UTC)

(ec) While I don't have any entropy/enthalpy data at hand for the reaction 4 Fe + 3 O₂ ⇌ 2 Fe₂O₃, I do seriously doubt that Fe₂O₃ notably decays into its elements at temperatures around 1700°C. What could happen instead is the following reaction: Fe₂O₃ ⇌ 2 FeO + O₂ (many transition metal oxides in higher oxidation states give off O₂ at higher temperatures, fx CrO₃ which becomes Cr₂O₃). According to our article, FeO (which is only stable at higher temperatures anyways) has a (measurable) boiling point of 3414°C, so it can't possibly start decaying into its elemnts at temperatures of 1700°C, or else there'd be nothing more left at 3414°C.

The carbon does indeed make the heat which is necessary to get the actual iron reduction reaction going. It first burns exothermically to CO₂ and then reacts with more coal to form CO, which is the actual reducing agent (see Blast_furnace#Chemistry). The product of the reaction still has some C in it, so I guess they're adding some excess C in the beginning to get all the iron(III) oxide reduced and after that they remove some of the excess C in further refinement processes. --178.26.171.11 (talk) 19:21, 3 December 2010 (UTC)

Cat's nipples

How many nipples has a female/male cat? 178.42.62.13 (talk) 11:17, 3 December 2010 (UTC)

Male cats, like female cats, have 6 nipples. Cuddlyable3 (talk) 12:19, 3 December 2010 (UTC)

Citation needed. Here's one with seven clearly visible, and presumably an eighth hidden by fur: [7]. (Note that a Google Image search for cat nipples may not be work safe.) That agrees with the number in the table at Mammary gland#Other mammals, though that table doesn't appear to have a source listed. TenOfAllTrades(talk) 13:33, 3 December 2010 (UTC)

Apparently the answer is 8. I googled "feline nipples", and this interesting page came up:[8] ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:22, 3 December 2010 (UTC)

human hunting

Say if humans never invented weapons or any current civilazation like today and stay like in the stone age what would we have used as weapons to kill prey and if not what would of we used to look for food would we have been scavengers, use plants as food or would we be using insects or fish as food.--213.94.232.217 (talk) 13:59, 3 December 2010 (UTC)

Tool use is pretty definitive for the idea of "human". The remnant stone age societies today use the same weapons that our stone age ancestors did - stone arrows, spears, axes, etc. Hunter gatherer societies do eat plants and insects and meat - but so do developed ones. We just (mostly) farm ours, instead of gather them, and some species are better adapted for farming than others, so we have a smaller variety. 75.41.110.200 (talk) 14:28, 3 December 2010 (UTC)

As the person above intimated, our connection to tool use is profound - we've used tools since before we were human. Our nearest ancestors, the chimps, use tools as well, though not nearly as sophisticatedly as we do. That being said, the diet of chimps is probably pretty close to what our pre-tool ancestors ate (.e. an omnivorous diet consisting of pretty much anything that they could safely get their hands on). Matt Deres (talk) 14:55, 3 December 2010 (UTC)

No i mean say if humans never invented tools or weapons how would we get our food then. --213.94.232.31 (talk) 14:51, 3 December 2010 (UTC)

In that case you would have to eat raw fruit and vegetables, and leaves and grubs and insects, like many other primates. But the making of tools is one of the defining characteristics of being human, so it's a somewhat meaningless question.--Shantavira|^{feed me} 15:00, 3 December 2010 (UTC)

Somebody mentioned recently that the human gut has evolved alongside cookery (making fire part of our phenotype, I suppose). Without tools we'd have different anatomy, and different brains, and be something like large chimps, only without the inclination to wave sticks around. I'm bemused by the questions "if humans never invented weapons ... what would we have used as weapons?" and to that part I can only answer "teeth". The reference to scavengers reminds me of neanderthals, whose large jaws are supposed to be for cracking bones to get at the marrow. Maybe your question is "what type of diet did our nearest non-tool-using primate ancestor have?". Human_evolution#Divergence_of_the_human_lineage_from_other_Great_Apes seems to say that ancestor was Paranthropus, and that article gives the answer "a diet of grubs and plants". Though, actually, it seems likely that everything that looks at all like a great ape will from time to time pick up a stick and make some use of it, so perhaps we need to go way back to an ancestor somewhat like a lemur; and even lemurs can be trained to use tools, though they haven't been seen using tools in the wild. Lemurs eat fruit, leaves, flowers, bark, sap, spiders, caterpillars, grasshoppers, the odd bird and lizard and by the sound of it pretty much anything else as well. 213.122.16.186 (talk) 15:20, 3 December 2010 (UTC)

on your assertion that the robust jaw of Neanderthals was "supposed to be for cracking bones to get at the marrow". Besides the fact that bones are extremely hard and difficult to bite into (few animals do it, considering the nutrient value), Neanderthals also had stone butchering equipment which could much more easily accomplish that task. The size of their jaws may have been influenced by their diet, but they were more robust than modern humans in most respects; cracking bones for marrow didn't give them their supraorbital torus, for example. Our article also notes that they were apex predators, like us. Matt Deres (talk) 17:50, 3 December 2010 (UTC)

Ah... maybe I'm getting confused with Homo erectus [9]. Recently I read, but I can't remember where (which probably means in reality it was about ten years ago) a theory which said, in essence, that one bunch of hominids had taken the evolutionary path of being able to think hard and run fast, while the other bunch invested much more heavily in being able to chew. 81.131.9.41 (talk) 19:27, 3 December 2010 (UTC)

(I have no idea what that site is, but google books says the text comes from the Gale Encyclopedia of Science. And I know it doesn't say anything about jaw evolution, in fact it mentions "sophisticated tools," but it does say they scavenged.) 81.131.9.41 (talk) 19:38, 3 December 2010 (UTC)

213's comment "Without tools we'd have different anatomy, and different brains" is correct. Take a look at Human_evolution#Use_of_tools: it suggests a sort of evolutionary virtuous circle where tool use allowed a more energy-rich diet, which in turn allowed selection for larger, more energy-consuming neocortexes which consequently promoted greater tool-use and so on. There's an extensive chicken/egg type debate about to what extent brain structure is dictated by behaviour and vice-versa as well (check out the Noosphere article), so even a hypothetical question regarding 'non-tool using humans' is difficult to meaningfully answer. Take a look at the first half-hour of 2001: A Space Odyssey for an entertaining take on some of the ideas. Blakk and ekka 18:20, 3 December 2010 (UTC)

If we had never invented tools, we probably would have gone extinct. It's our ability to control our environment that makes us unique among animals, and improves our survival chances. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:19, 3 December 2010 (UTC)

Bismuth(III) iodide dilemma

Why does bismuth(III) iodide say that it is a greenish-black solid in infobox, gray-black solid in article, and pale yellow solid in picture? Is it different forms like alpha and beta forms? Thanks, --Chemicalinterest (talk) 14:06, 3 December 2010 (UTC)

Sigma-Aldrich doesn't list a color in their MSDS for bismuth(III) iodide, but here are a couple of others offering up gray, dark grey, or red(?)(!). My rubber bible (76th ed.) says 'black hexagonal crystal'. A cursory search doesn't reveal any suggestion that bismuth iodide can form two different solid phases under normal conditions, but I can't rule it out.

My strong suspicion is that this is a dark-gray-to-black (faintly colored under appropriate lighting) crystalline material, and that our article contains errors. It looks like all of the bismuth(III) halide salts (with the exception of the fluoride) were photographed by the same individual as part of a large batch of similar images; one wonders if he made – or was the victim of – an inadvertent labelling error. TenOfAllTrades(talk) 15:01, 3 December 2010 (UTC)

Parrots cracking bones to get the marrow...

(Matt Deres' answer to the 'human hunting' question above got me thinking) If you give a bone (say, a chicken leg) to a parrot - video example, it will eat the meat and then may decide to crack the bone open to eat the marrow inside.

Do they actually do this in the wild? Parrots are not generally predatory, so I'd assume that any bones they'd find to gnaw on in the wild would have to come from scavenged carcasses. --Kurt Shaped Box (talk) 19:06, 3 December 2010 (UTC)

I seem to recall that some birds, and parrots specifically, have trouble getting all the minerals they need in their normal diet, so will resort to doing odd things like eating clay. Getting the iron out of bone marrow might also be normal for them. StuRat (talk) 04:35, 4 December 2010 (UTC)

Might not the cracking of the bone be a normal behaviour to be expected of seed eating birds. If you give anything to a parrot one of the first investigatory procedures is to give it a good going over with its beak. It is conceivable that the parrot assumes the bone is just another seed which needs to be cracked open and the contents consumed. Richard Avery (talk) 08:36, 4 December 2010 (UTC)

According to our article on parrots, they eat clay because it "both releases minerals and absorbs toxic compounds from the gut". It also mentions that some parrots are predators, noting in particular the hunting habits of keas, the Antipodes Island Parakeet, and Golden-winged Parakeets. I did a quick Google search for the original question and found a quote from a book called Veterinary Nursing by D. R. Lane, B. Cooper (I can't even get a proper preview): "Most of the large parrots are omnivorous in the wild, eating a mixture of fruit, vegetables and seeds, plus insects and carrion..." and the rest is cut off. Hopefully, someone can get a proper reference for us. Matt Deres (talk) 19:46, 4 December 2010 (UTC)

is it a coincidence that there are 12 months and 12 hours?

is it a coincidence that there are twelve months in the year and twelve hours in the day (a.m. or p.m.) or is it one of nature's beautiful symmetries? 82.234.207.120 (talk) 20:53, 3 December 2010 (UTC)

One wikipedia reference is 12-hour clock, which mentions the antiquity of the system. Precisely why 12 and not 10 is unclear, but I can imagine some reasons for it. There might be more detailed info elsewhere. There should be something in Calendar about 12 months in the year, but that was not a uniform standard. Lunar calendars typically have 12 lunar months (or "moons") within a given year rather than using the 30-31 system, and they catch up by adding a 13th month every few years. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:07, 3 December 2010 (UTC)

Months as we know them now are based (loosely/approximately) on "lunar cycles per year"...that's Nature's doing. But there have not always been 12 anyway. The division of a day into hours is completely a human invention (and aren't there actually 24 of them?). The most plausible story I usually hear is that it allows many different subdivisions without getting wacky fractions (10 only allows 10/5/2/1 whereas 12 allows 12/6/4/3/2/1). DMacks (talk) 21:19, 3 December 2010 (UTC)

Phrased another way, 12 is related to a factorial (4!) while 10 is not. This is true in any number-notation system, so even if ancient clock-makers did not use a base-10 numeral system, they still would have understood a special significance for the value "12". "10" only seems like a special number when we use a decimal number-system; it has no real natural significance (other than equaling the most common number of fingers on humans). You might be interested in Sexagesimal (base-60) numerals that were used by ancient Babylonians and Sumerians - there are 24 (4!) hours in a day for a similar reason; 60 minutes in an hour; 360-degrees in a circle, and so on. Nimur (talk) 21:28, 3 December 2010 (UTC)

Note that decimal time and months were implemented during the French Revolution, but did not catch on broadly and even in France were eventually eliminated. In any case, as all have stated, the divisions are arbitrary (with the exception of the number of rotations of the Earth in a year, which is a constant—if you don't get the number of days in a year right, your seasons won't match up on a calendar from year to year), but different systems allow you to do different types of calculations more easily. --Mr.98 (talk) 04:01, 4 December 2010 (UTC)

The fixed periods in nature, visible from Earth, are the day, periods between tides, lunar month (not what we call a month), year, and perhaps seasons (4 divisions of a year between solstices and equinoxes). Others, like a sunspot cycle of 11.2 years or Halley's Comet cycle of 76 years, could also be included, but are less important to our everyday lives. StuRat (talk) 04:33, 4 December 2010 (UTC)

The easy divisibility of 12 into various fractions is also probably why there were 12 inches in a foot. Just one more example of the superiority of the old English system. :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:59, 4 December 2010 (UTC)

You might want to check out the Dozenal Society. See also Duodecimal#Advocacy_and_.22dozenalism.22. There are a lot of good reasons to go base twelve. Too bad our ansectors ended up with 10 fingers and developed our utterly impractical base 10 system (how often do you find yourself happy that it's easy to divide by 5? I'd take the factor of 3 any day. The extra factor of 2 is nice as well). Buddy431 (talk) 05:51, 4 December 2010 (UTC)

Edit: If your British, you might prefer to align yourself with the DSGB. Of course, not everyone is happy with these upstarts. Buddy431 (talk) 05:52, 4 December 2010 (UTC)

I can't find a reference right now, but base-12 counting systems are also based on counting on the fingers. Not counting your thumb; you have 12 knuckles on each hand. Using your thumb as a "place holder" on each knuckle enables easy counting in base-12. I read somewhere that the connection to the 24 hour day and all of our other base-12 derived time units derive from counting in base-12 in this manner. Two sketchy sources which confirm this are here and here, see the second response.. --Jayron32 06:22, 4 December 2010 (UTC)

I'm amazed that no one has mentioned the Zodiac yet. While I'm speculating here, and I don't know if the historical truth can be determined, but consider that someone using a lunar month, the most obvious division, is going to see the sun or a full moon turn up in about 12 different places in the sky in a year. This leads naturally to the idea of identifying what time of year it is based on which of 12 astrological signs the sun and/or moon are located in. Such a basic astrology is indeed useful in predicting one's success when planting crops!

Now it is also possible to divide a day according to the rising sign, though admittedly this yields 12 units rather than 24, and the time of day at which a constellation rises varies during the year. Still, I'm suspicious of some sort of link. Wnt (talk) 11:42, 4 December 2010 (UTC)

Sail and oar power

Why exactly were oars abandoned for sail power? Was it to make room for more cannons? It seems that something more like a Galleass would be the best combination, being able to head straight into the wind without tacking. --T H F S W (T · C · E) 21:05, 3 December 2010 (UTC)

Galley might provide some answers. Galleys in fact had sails. Oarsmen provided better maneuverability. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:16, 3 December 2010 (UTC)

Exactly. So why were they given up? --T H F S W (T · C · E) 21:23, 3 December 2010 (UTC)

Well, you can reduce the crew size if you are not going to be rowing a lot. That means you can go further before you need to take on more provisions. Googlemeister (talk) 21:30, 3 December 2010 (UTC)

According to the "Decline" section of that article, they basically went obsolete as new technologies came along. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:33, 3 December 2010 (UTC)

This is the second essentially tautological answer you've given in as many days on here, Bugs! "Why was a technology phased out? Because new technologies made it obsolete." Reeeeally, now? --Mr.98 (talk) 04:06, 4 December 2010 (UTC)

Also oar power requires a flat design that makes ships very vulnerable to storms. Looie496 (talk) 22:27, 3 December 2010 (UTC)

I think that's the same reason as Bugs gave (the newer ships could cope with rough seas). The OP was talking about something like a galleass, though. That's not the same as a galley, and it's not flat, so why isn't it the best of both worlds? I can't see the drawback of having oars as an option (even if they're not very efficient because they're positioned high up). The galleass article says Henry VIII built a lot of them, and then a couple of decades later had all their oars removed and turned them into pure sailing ships, but it doesn't say why. 81.131.6.177 (talk) 22:37, 3 December 2010 (UTC)

All those oarsmen had to eat, drink and sleep the whole time the galley or galeass was in commission, so the crews were expensive, particularly if they were serving willingly. A galley or galeass consequently was a short-ranged vessel that had to stay close to a convenient port or risk starvation, and had little room left for more than a couple of guns. They were also quite lightly built in order to keep oar propulsion within the realm of possibility. I suspect that Henry's ships were slugs under oar power. After naval guns were refined a little bit (around Henry's time) a moderately well-armed sailing ship could sink a galley from a distance with little trouble as long as the wind was favorable; oar power was only an advantage in close quarters or an unfavorable wind. Acroterion _(talk) 00:04, 4 December 2010 (UTC)

It occurred to me that the manpower requirements made galleys not cost-effective compared with newer technologies, but the article is kind of vague on that issue. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:19, 4 December 2010 (UTC)

I see that the Girona (ship) made it all the way from Spain to Ireland, the long way round, and had 1300 people on board when she sank (plenty more than the 370 I estimate it would take to man the oars), but I think that voyage was largely accidental, so fair enough. Also the ships illustrated in the Galleass article have (it looks like) 18 and 22 guns, which is more than a couple, but hey, good points anyway. (Perhaps they're very small guns.) 81.131.39.230 (talk) 01:29, 4 December 2010 (UTC)

Patrick O'Brian discussed the issues of sail vs. oar extensively in the Aubrey–Maturin series, and while that was a work of fiction, it was based on years of O'Brian's readings of logbooks and everything naval he could find. It was not uncommon for small ships, say sixth-rates to have sweeps - long oars to help move the ship in an emergency or for convenience, even in Napoleonic times. Anything bigger than, say 200 tons, though, was impossible to move by oar power. Galleys draw little water and displace at most couple of hundred tons. A 400-700 ton fifth-rate was not moveable by means other than wind or towing. A galeass was probably right on the edge of being too big to move by oar and not built heavily enough to carry heavy guns; as the article notes, they evolved into fifth and sixth-rates: frigates. In the 17th century a nine-pounder (maybe weighing a ton) was a big gun, by the 18th century ships were carrying 24-pounders, and by the 19th a third-rate ship of the line carried 32-pounders (6000+ lb each) and was built to stand in a line of battle and beat the hell out of a counterpart a couple of hundred yards away, and to receive the same. Galleys couldn't possibly do that, nor could they raid an enemy's commerce more than a hundred miles from their home port, or stay at sea blockading an enemy port for months on end. In any case, galleys and galeasses spent most of their time sailing, only using oars when becalmed or when it gained a tactical advantage. They were sprinters and bantamweights; sailing ships were both distance runners and heavyweights, to mix sports analogies. Acroterion _(talk) 02:55, 4 December 2010 (UTC)

So in other words, if a ship displaces too much water, it is immovable by oars (which would be the reason galleys would have flat bottoms)? And about the argument about the extra crew: as already pointed out, a large ship would have well over 300 men aboard, so there would be plenty to row. One more question: can a galley be made more stable by adding a very large keel? --T H F S W (T · C · E) 22:10, 4 December 2010 (UTC)

The more a ship displaces, the more power needed to move it. "Plenty to row" is not necessarily so: if we assume that a man can produce 1/4 horsepower for a short period of time (which is probably generous), for less than an hour, you have at most a 75 horsepower engine to move several hundred tons for a short time. You can sail a fairly large ship indefinitely with thirty men, leaving plenty left over for guns and boarding actions. Oars aren't an efficient means of propulsion, and need room inside the ship that could be devoted to armament and cargo. If you want to fight, you'll need four to eight men per gun, who won't be available to row. 20 guns will need 80-160 men to serve them (although if you only wish to fight one side at a time you can have the crews run to the other side), plus powder boys and gunner's mates to fill cartridge and carry shot. Keels weren't very common on large ships, as they already drew a substantial quantity of water and didn't need something that could be scraped off - or worse sticking out from the bottom. While a keel will add some stability, it's more useful for countering leeway (the tendency for a sailing ship to slide sideways in a wind from the side), and is hard to construct durably in a large wooden ship. Ballast was used to lend stability, which again adds mass; I don't see any advantage to much ballast or a keel in a rowed vessel. The big advantage a galley had that a sailing ship didn't was an ability to accelerate rapidly and to maneuver, turning in its own length, which heavy ballast or a big fin would diminish. Think of racing shells - long, slender and and displacing virtually nothing. Galleys would use swarming tactics against sailing ships, and would decline a one-on-one action unless there was no wind, which is a fairly rare circumstance near the shore. Acroterion _(talk) 02:38, 5 December 2010 (UTC)

Also, rowed ships must be relatively low to the water; large rowed ships do poorly in the stormy North Atlantic (and a Viking ship is too small to be a ship of the line). The Atlantic powers invested in sailing navies, while France also maintained a Mediterranean fleet of galleys out of Toulon into the eighteenth century. Septentrionalis PMAnderson 21:45, 7 December 2010 (UTC)

if all small arms and heavier munitions disappeared, would the world be a safer place?

if all small arms everywhere in the world instantly disappeared (and for whatever reason could not be reproduced), along with all munitions heavier than small arms, would the world be a safer place, or less safe for some reason I'm not imagining clearly? 82.234.207.120 (talk) 23:09, 3 December 2010 (UTC)

It's quite often argued that higher weapons technology makes wars shorter. In this particular case, we'd return to fighting wars with bows and arrows and swords. Larger armies would be needed, which would fight more chaotically and take longer to kill the enemy, causing more starvation and disease for civilians near the battles. Also being clubbed to death is not really any safer than being shot. 81.131.6.177 (talk) 23:24, 3 December 2010 (UTC)

This is really more of a humanities question, unless you are wondering by what process this instant disappearance could occur. That said, maybe some arguments in this article (and related ones) might interest you: Political arguments of gun politics in the United States. The US has a long history of just this sort of debate, and there are a number of arguments on both sides of the aisle that could offer some insight. TomorrowTime (talk) 23:34, 3 December 2010 (UTC)

This is also a speculative question, so we can't really answer it definitively. But you might find the sociological research published by various think-tanks like the Brookings Institute, the Hoover Institute or the RAND Corporation worth reading. Arguably, some of these institutes espouse a right-wing "neoconservative" philosophy that advocates more low intensity warfare as a means to ensure less high-intensity warfare overall. You can search their published archives to find their official policy advisories related to, for example, arms control, firearm legislation, and so forth. While I don't necessarily agree with many of the published opinions of these organizations, they have a knack for recruiting some of the greatest political and military minds in the world, and their publications are often extremely well-researched. Food for thought, if not a prescriptive panacea for global policy. Nimur (talk) 23:37, 3 December 2010 (UTC)

I think a look outside the USA is important on this one. Australia has always had much lower gun ownership than the USA. After the Port Arthur Massacre in 1996 the laws about gun ownership became considerably tougher. The vast majority of Australians don't own guns. And by most measures it is a safer place than the USA. I know there will be many other factors at play, but it's an interesting starting point for discussion. HiLo48 (talk) 23:42, 3 December 2010 (UTC)

Right - there's a sort of spectrum of "danger" ranging from chronic criminal activity all the way to military armed conflict. Depending on your school of thought, this distinction between crime and war is either a continuum of magnitude, or two unrelated issues. Nimur (talk) 23:51, 3 December 2010 (UTC)

Look at how certain African countries have suffered with the machete as the principal terror. 75.41.110.200 (talk) 00:14, 4 December 2010 (UTC)

I'd love to look, but where? HiLo48 (talk) 00:16, 4 December 2010 (UTC)

Rawandan Genocide and Darfur Genocide. StuRat (talk) 04:12, 4 December 2010 (UTC)

Another example is the UK, where per capita murders are a tiny fraction of those in the US. The answer to the OPs question is, yes of course it would. 92.15.20.70 (talk) 00:18, 4 December 2010 (UTC)

How do murders in the UK compare before and after gun control came in? But of course the answer to that question wouldn't conclude the argument ... and neither would any other example, because we can endlessly claim special circumstances and confounding factors (which may or may not be really present). 81.131.6.177 (talk) 00:43, 4 December 2010 (UTC)

The per capita murder rate in the UK is nearly a quarter of the rate in the US - List of countries by intentional homicide rate. For gun killings its bound to be even more dramatic than that. "After gun control came in" - guns are very rare in the UK. I've only seen one twice in my life - both shotguns used in the countryside. 92.24.177.111 (talk) 12:23, 4 December 2010 (UTC)

Yes, if guns were banned in the US (requiring a repeal of a Constitutional Amendment), crime might actually get worse in the short run, as law abiding citizens surrendered them and criminals kept theirs. However, over time, illegal guns would be either confiscated, disposed of by criminals, or just wear out. Thus, eventually, criminals would have fewer guns. Another side benefit might be that criminals would keep a gun that was used in a crime, knowing they could never replace it, and thus get caught with the gun as evidence against them. You could also expect some old and poorly maintained guns to misfire or hopefully even blow up when the criminals use them. StuRat (talk) 07:36, 6 December 2010 (UTC)

Prohibition doesn't work. If someone wants to kill, they'll find a way. The issue isn't guns, the issue is why do people use them? Fix that, and the guns problem fixes itself. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:53, 4 December 2010 (UTC)

Someone who wants to kill from short term anger will usually calm down over time. The lack of a suitable tool for easy killing during that period will prevent killing from happening. Time is a wonderful healer. If a gun is readily available that healing won't happen. HiLo48 (talk) 01:10, 4 December 2010 (UTC)

No question it's too easy for a hothead with a gun to use that gun. But gun ownership, within certain limitations, is written into the U.S. Constitution, and that's not likely to change anytime soon. What the OP is wanting is something like when the Organians worked it so the Federation and the Klingons were rendered incapable of using their weapons and were compelled to sign a truce. Divine intervention, effectively. Real life doesn't work that way, and as long as someone has something that someone else wants, wars and violence will continue. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:17, 4 December 2010 (UTC)

Since we're in the science section, I'd have to ask whether the ban on "small arms" extends to the gyrojet, crossbows, flame-throwers, RPGs... because a world where none of these mechanisms work has very different physics indeed. I suppose if you ruled people were indestructible then they wouldn't get hurt, but then enemy soldiers could just walk up to them, chain them up, and toss them down very deep holes to spend a dull eternity. Wnt (talk) 01:33, 4 December 2010 (UTC)

I feel the need to trot out the familiar old argument (it needs a bit of exercise now and again) that laws against gun ownership, by definition, prevent law abiding people from having guns, while murderers, by definition, are not law abiding. (This doesn't actually contradict what you just said; without gun laws, generally well-meaning hotheads sometimes shoot people, and with them, innocents are unarmed while gangsters still have guns.) 81.131.39.230 (talk) 01:40, 4 December 2010 (UTC)

....in the USA. And that's the point. In countries without a gun culture, there are just simply fewer guns. It's still harder for criminals to get them. The big worry in my Australian city right now is not guns. It's the claim by the righteous media that there is a growing number of youths with knives. (Anyone remember Romeo and Juliet?) Knives, of course, aren't normally deadly unless you're very close to the victim. Guns are deadly from a long way away. The best response I've heard to Americans quoting their constitutional right to bear arms is that it should be restricted to the types of arms available when that right was created. HiLo48 (talk) 02:10, 4 December 2010 (UTC)

In my past life in the London insurance market I used to see the claims for the American National Rifle Association's accident policies and can say that the world would definitely be safer without guns, especially in people's homes. "I forgot it was loaded", "the trigger got caught on a coat hook", "my son / daughter /wife / neighbour / cat / dog was playing with it" and so on. It's a bloodbath out there! Alansplodge (talk) 02:41, 4 December 2010 (UTC)

re: "it's a bloodbath out there!" Just out of curiousity, have you ever gotten a claim where nothing happened at all? If not, you might want to read about selection bias before armageddon! 82.98.48.252 (talk) 15:25, 4 December 2010 (UTC)

I wonder how the rifle claims compare quantitatively with claims connected with automobiles. If anything, it's the car that should be banned. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:54, 4 December 2010 (UTC)

If people were reduced to hand-to-hand combat, that would favor the nations with the largest populations, such as China and India, which would probably split Asia between them. Perhaps if all the Europeans worked together, they could stop the Chinese from advancing into Europe. StuRat (talk) 04:20, 4 December 2010 (UTC)

That's where bombs come into the picture. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:54, 4 December 2010 (UTC)

Wouldn't bombs be counted under 'munitions heavier than small arms'? On the other hand it's not clear to me that some kinds of chemical weapons and particularly biological weapons would count as 'munitions heavier than small arms' Nil Einne (talk) 07:59, 4 December 2010 (UTC)

Let's not forget fire. In a country with gun control, one can always chain the doors to the ex's tenement and throw in a few Molotov cocktails; it has the added advantage that the police would have many suspects to consider. Likewise a war can be fought with fire balloons, "bat bombs" [incendiaries, that is], and the ever-handy flame thrower. Wnt (talk) 11:51, 4 December 2010 (UTC)

You could buy a gallon or two of gasoline and use it to burn down a building. Violence always finds a way. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:55, 4 December 2010 (UTC)

Do you mean small arms in private homes or small arms for the military? --Stone (talk) 17:28, 4 December 2010 (UTC)

@Bugs "it's the cars that should be banned", First off compare how many cars are used with malice aforethought to kill people, almost all auto deaths are caused by stupidity and lack of judgement. You have a personal point to make but don't assume the audience is naive. Richard Avery (talk) 08:45, 5 December 2010 (UTC)

Without firearms and munitions, wars would most likely be fought biologically, and would be incredibly nasty. Googlemeister (talk) 16:17, 6 December 2010 (UTC)