Wikipedia:Reference desk/Archives/Miscellaneous/2011 March 18

= March 18 =

Dilemma
Somewhere I had read the story of creature that would die of starvation if fed in two pots at equal distance from it; it will starve while trying to make a choice as to which one is the nearest. I believe it could be fictional and that is why I did not go to RD(Science). Can anyone help me with it name? 14.139.128.14 (talk) 05:28, 18 March 2011 (UTC)


 * I believe there are multiple examples in the folklore of different cultures, but the example most people probably think of is Buridan's ass. Does that help? –  OhioStandard  (talk) 05:54, 18 March 2011 (UTC)
 * Yes; that was it. Thank you.  14.139.128.14 (talk) 13:31, 18 March 2011 (UTC)
 * The story is indeed fictional. Living creatures do not monitor everything in all directions continuously, instead they scan their environment taking samples of sensations at different times. The starving creature will choose the first pot that it notices. Cuddlyable3 (talk) 14:18, 18 March 2011 (UTC)
 * Yes, most creatures would head for the upwind pot because scent is a stronger motivation than vision, especially in rodents. Mammals will often rush from one to the other to see which is best.  Sorry, this is "OR" from observation.  Can anyone find any research?    D b f i r s   08:27, 19 March 2011 (UTC)

Turning the Sahara Desert into arable farmland, is it possible?
I have recently been thinking of this question and I haven't got a logical answer,would a great ammount of water do it or would it just dry out? — Preceding unsigned comment added by Mickey 63 (talk • contribs) 14:15, 18 March 2011 (UTC)


 * Probably not. Without a constant source of water, the same forces that made it dry in the first place will make it dry again. Chief among these is, of course, the lack of rain. Filling a desert full of water would increase the rain down-wind of the desert, but not much in the desert itself.
 * You may find the Rain follows the plow article interesting. APL (talk) 14:27, 18 March 2011 (UTC)


 * Apparently the CIA once planned to flood the Qattara Depression, which would have somehow brought about peace in the Middle East. Adam Bishop (talk) 14:30, 18 March 2011 (UTC)


 * There is also the issue of soil quality. Deserts typically don't have a lot of nutrients in the soil (because there's no biological matter to provide nitrates, phosphates, etc, and poor soil quality often leads to desertification).  This can be solved with fertilizer.  Deserts also tend to have alkaline soils (I'm not sure about the Sahara), although using fertilizers will tend to increase acidity. --Colapeninsula (talk) 14:59, 18 March 2011 (UTC)


 * This discussion reminds me of Norman Borlaug, who saved millions of people from starvation with his innovations in agriculture in the Indian subcontinent. The article says, "Those elements that allowed Borlaug's projects to succeed in India and Pakistan, such as well-organized economies and transportation and irrigation systems, are severely lacking throughout Africa, posing additional obstacles to increasing yields."  There is also the issue of whether the introduction of fertilizer would be good for the environment in Africa.  The 5th and 6th paragraphs of this article discuss this debate. Unfortunately, as this article notes, the debate "is currently phrased mostly in environmental terms, not in terms of saving lives." --Viennese Waltz 15:11, 18 March 2011 (UTC)


 * Some deserts tend to bloom after a minor rainfall. However the Sahara was once wet and this climate was dependant on the North African Monsoon. You may be interested in Oasis, Sahel drought, Canary Current, Nile Valley, Reforestation, Aoukar Depression, Cave of Swimmers and Climate change and agriculture. ~ A H  1 (TCU) 15:20, 18 March 2011 (UTC)


 * If I recall, the humans in Battlefield Earth do exactly this (probaby with the aformentioned Qattara Depression. In the book it worked, though I can't recall if there was any science in there to back up why (and any science presented by L. Ron Hubbard should probably be taken with a large grain of salt). i.m.canadian (talk) 18:00, 18 March 2011 (UTC)


 * This discussion reminds me of an article I saw several years ago in The Wall Street Journal entitled, as I recall, "Africa can feed itself: Should it?". I observe that performing a web search for the phrase "Africa can feed itself" yields some very interesting results. –  OhioStandard  (talk) 18:20, 18 March 2011 (UTC)


 * Ah, yes, arable land. "That is land that is actually tilled ... by Arabs".  (Peter Cook).  :)  --   Jack of Oz   [your turn]  18:51, 18 March 2011 (UTC)


 * Nah, that's just Arab bull. :-) StuRat (talk) 19:08, 18 March 2011 (UTC)


 * There is also the Sahara Forest Project, seeking to use solar power to de-salinate seawater to use for growing stuff in the desert. A short Wikipedia article is at Seawater Greenhouse. Jørgen (talk) 19:48, 18 March 2011 (UTC)


 * To answer the OP. You cannot add water to sand and make it farmable. You need soil, specifically with a lot of top soil and nutrients. Sand will always just be sand, and will never grow anything, so certain parts of the Sahara will never really be arable.(until the continental plates shift of course, and it is no longer a desert)AerobicFox (talk) 21:38, 18 March 2011 (UTC)


 * I disagree. If water was present, then plants, insects, and birds would soon appear, poop, and then die, steadily building up the soil.  In a few years you would have land suitable for at least some crops, particularly if you were willing to add fertilizer to fix any deficiencies.  However, since most crops can't tolerate much salt, you would need to flood the desert with fresh water, not salt-water from the Mediterranean. StuRat (talk) 22:03, 18 March 2011 (UTC)


 * Maybe in a few dozen years. Not something that will happen in 3-4 years.  Googlemeister (talk) 16:38, 23 March 2011 (UTC)


 * Here's a National Geographic article from a couple of years ago which suggests it is already happening: ... but they weren't sure whether it was genuinely a trend or not. 81.131.22.230 (talk) 23:03, 18 March 2011 (UTC)

"Just add water" is a tried and true technique for turning desert into farmland. DOR (HK) (talk) 05:38, 21 March 2011 (UTC)

NBC color logo notch in blue feather
What is the significance of the open notch in the "Blue" feather? —Preceding unsigned comment added by 96.225.136.206 (talk) 15:18, 18 March 2011 (UTC)
 * It's supposed to be a peacock's head and tail. The "notch" is its beak Rojomoke (talk) 15:50, 18 March 2011 (UTC)

Soggy pizza
I like to make Hawaiian pizza at home, as follows:

1) First I cook a frozen cheese pizza in a portable convection oven until the cheese melts (about 5 minutes).

2) Then I add cubed ham and pineapple chunks, and cook for another 5 minutes.

3) Finally, I garnish with flat leaf spinach and serve.

The problem is that both the ham and pineapple drip water onto the pizza when cooked, leaving it soggy. A microwave makes it even soggier. My convection oven recycles the air, and one that vents it might help, but probably not much. I don't think dehydrated ham and/or pineapple would taste the same, so that's not a solution. I am considering getting a dehydrater, not to dehydrate the ham and pineapple first, but to cook the pizza in there with the toppings, to hopefully dry it out a bit. Any thoughts on this or any other approach ? StuRat (talk) 20:41, 18 March 2011 (UTC)


 * My first thought is that that is just another clear sign that pineapple does not belong on a pizza. But leaving my personal pet peeves aside, have you tried adding the pineapple to the pizza during the first stage of your cooking cycle? Perhaps the longer cooking time will vaporise some of the excess juices of the pineapple? --Saddhiyama (talk) 20:47, 18 March 2011 (UTC)


 * Then I'd have frozen cheese under it. StuRat (talk) 20:58, 18 March 2011 (UTC)


 * Perhaps you should try a conventional oven then? You have obviously cut a lot of corners already, it seems very optimistic to expect a flawless result under those conditions. --Saddhiyama (talk) 21:01, 18 March 2011 (UTC)


 * My convection oven is electric, while my conventional oven burns gas, so that introduces additional water vapor as a combustion product. I don't see how that would help. StuRat (talk) 21:05, 18 March 2011 (UTC)


 * That will be horrible. You'll have much better luck sauteing the ham and pineapple in a frying pan for a couple of minutes before adding them, and compensating by giving them less time in the oven. Looie496 (talk) 20:56, 18 March 2011 (UTC)

Cook the dough until it forms a slight crust on top - then add the wet ingredients (which are room temperature or so). If you use olive oil on top of the bread, that will also prevent water from making the bread soggy (oil and water do not mix). Collect (talk) 21:31, 18 March 2011 (UTC) (Yes - buy pizza dough instead of a frozen pizza) Collect (talk) 21:32, 18 March 2011 (UTC)


 * Have you patted the pineapple and ham quite dry? It should be extremely dry (not dehydrated) before being put on the pizza — pat them down with paper towels first. (Same with any "wet" pizza ingredients.) (Incidentally, if you have a food processor, making amazing pizza dough is dead easy and a lot cheaper than buying the pre-made crusts, even if you use wonderful flour. I'm quite partial to King Arthur flour for pizzas.) --Mr.98 (talk) 21:46, 18 March 2011 (UTC)


 * Why not buy a frozen Hawaiian pizza - one with the ham and pinapple dry and already there? Astronaut (talk) 11:34, 19 March 2011 (UTC)


 * The main reasons are cost and health. Any frozen pizza beyond cheese, pepperoni, and "combo" (pepperoni, sausage, and an "angel dusting" of green pepper) costs many times as much.  I can get a 9-10 ounce frozen cheese pizza, without any added trans-fats, for $1.  Also, if I add my own toppings I can control the fat, sodium, etc., better. StuRat (talk) 18:08, 19 March 2011 (UTC)


 * It actually isn't any more expensive to make your own pizza truly from scratch; the problem you are having is that you are starting from non-ideal conditions by working with a cheap frozen pizza. If you want a proper Hawaiian pizza, where you get a good, crispy crust and properly cooked ingredients, than my suggestion is:
 * Make your own dough. Its a pretty simple recipe, and while it does take some time, you can make it ahead of time and refigerate it for a day or two.
 * Buy a pizza stone. One of the problems with a home oven vis-a-vis commercial pizza ovens is that they aren't hot enough.  Good pizza requires very fast cooking times, with the pizza cooked either via conduction by cooking directly on the metal (or ideally brick) floor of the oven, OR via radiation by cooking directly over an open flame.  You really need a blistering hot surface to cook a pizza on, something that can hold the heat and transfer it quickly to the crust.  Pizza stones allow you to do this at home; you preheat the oven with the stone in it, and the heavy mass of the stone means that it will hold enough heat energy so it can replicate the effect of commercial ovens.
 * Time is the key. There's a reason why cheap, frozen pizzas taste vastly inferior to those prepared in pizza restaurants, and its that you can't get something for nothing, temporally speaking.  Proper pizza (indeed, all superior cooking) requires the proper time to be taken, and if shortcuts are taken, the result is obvious in the end product.  If good pizza could be made quickly and cheaply and be of indistinguishable quality from the more carefully made pizza, everyone would be doing it.  What you make up for in time you always get back in quality.  Its just that the shortcuts you are taking (putting your own toppings on frozen pizza) literally cannot be optimized to produce a product of reasonably good quality.  -- Jayron  32  00:23, 20 March 2011 (UTC)


 * It doesn't take very long if you use the right recipe. We use "fast rising yeast" (check the baking section of the supermarket) and the whole thing takes, I don't know, 25 minutes total, if you have a food processor (which saves you having to knead it by hand). (Google "fast rising pizza dough" for lots of recipes.) OK, that's more than it takes to microwave something. But it's on part with what it takes to use a convection oven. And the product is much, much better. Way better than you'll get at your standard greasy cheese restaurant, too. (Though this has to do with buying good flour and fresh cheese, which make pretty much all the difference.) --Mr.98 (talk) 02:18, 21 March 2011 (UTC)


 * Fully homemade pizza just wouldn't fit into my lifestyle. I typically might make a pizza during an online Scrabble game.  During an opponent's turn, I put the frozen pizza in the convection oven.  A few minutes later, I return and add toppings.  A few minutes later, I grab the finished pizza and eat it in front of the computer while considering my next move.  Each of these 3 breaks only takes about a minute.  If instead I took a 25 minute break, then my timer would run out and I would lose.  Also, I wouldn't want to have a dirty food processor that needs washing later on (my method generates zero dishes, as I use the cardboard box as the plate for the pizza).  So, yes, I realize that given my constraints I won't have the best pizza in the world.  I don't expect that, just something edible, and hopefully not soggy. StuRat (talk) 06:02, 21 March 2011 (UTC)


 * You can do all of the prep work ahead of time, and the actual down time during your scabble game can be quite minimal. You could literally do the crust one day when you have the 25 minutes, put it in the fridge, come back the next day, spread it out and add the sauce and cheese.  Start playing scrabble, when you get hungry, throw on the pinapple and ham, toss it in the preheated oven.  Your missing time from your scrabble game will be identical as the frozen pizza, if you only take the time to plan ahead knowing you are going to want pizza when you play scabble.  That 25 minutes prep time doesn't have to take place during the scrabble game; after all, pizza restaurants don't start mixing the dough from first principles, they have everything ready to go, and toss the ingredients on and put it in the oven when you order it.  You can do this too.  This only takes some preparation ahead of time (what cooks call mise en place) and you will be ready to go.  -- Jayron  32  22:33, 21 March 2011 (UTC)

OK, thanks everyone. StuRat (talk) 15:36, 23 March 2011 (UTC)

Weird TV colour problem
Over the past month or so, my TV has developed a strange condition where a large part of the left side of the screen is "paler" and in a different colour than the right. It's most noticeable when the colour is supposed to be red - it shows as bright yellow or brick-orange, depending on the shade of red. Blue comes out as a sort of sickly light purple. Dark green is just a paler green. Other colours seem unaffected. My sense is that the area has increased in size; it started as a small strip over near the left side, and even when I pointed it out to my partner, he couldn't see any problem. But now it takes up most of the left side of the screen, and I fear it's inexorably spreading. The TV is at least 10 years old, but that's not ancient in TV years. Needless to say, but I'm saying it anyway, it's just a TV, not an LCD/plasma. Is this a common problem (I've never heard of it before) and can it be fixed or will the screen or the whole apparatus need to be replaced? --  Jack of Oz   [your turn]  22:21, 18 March 2011 (UTC)


 * By "just a TV", I assume you mean a CRT. I had a similar problem and noticed that a magnet can affect the color.  Try placing it on the affected side and moving it around a bit, to see if you can't improve the picture somewhat.  However, I don't think there's a perfect cure, so it might be time to replace the old set. StuRat (talk) 22:32, 18 March 2011 (UTC)


 * I expect the CRT shadow mask may be magnetised though I think this normally gives a coloured area in the middle of the screen. TVs should demagnetise the mask when they are switched on.. Maybe the degaussing has gone wrong. This says you may be able to degauss using a CRT computer monitor but I have my doubts (the site I wanted to link to is spam blacklisted so I am trying disguise: www.ehow.com/how_2041471_degauss-tv.html ). My CRT TV developed this fault many years ago but after a couple of days the colour problem faded away and the set was perfect again. No idea why but there is hope yet! Thincat (talk) 23:01, 18 March 2011 (UTC)


 * Thanks to both. Could it have anything to do with sinister emanations from the set-top box, which is close by? (It's also on the left of the screen, which I how I know it's sinister.)  I know that when I want to watch a DVD, I have to switch the set-top box off because it interferes with the picture.  Although, even when I do that, the screen colour issue still seems to be there, so maybe I'm talking out of my own set-top box.  :)  --   Jack of Oz   [your turn]  23:14, 18 March 2011 (UTC)


 * Yes, interference is a possibility. I had a TV and computer monitor too close, and they messed with each other.  Try moving them farther apart and see if that has an effect.  You might also want to unplug the set-top box, as a test, since it still has some power to it, even when switched off. StuRat (talk) 23:20, 18 March 2011 (UTC)


 * We might be on to something there. I just tested a DVD and it showed no sign of the colour problem at all.  Funny, last time I put one on, I could have sworn .... So, it's looking like an external interference problem rather than something internal to the TV set itself.  The set-top box is on a fairly short lead at the moment, but I'll put it on an extension lead and get it away from the TV and see what happens.  --   Jack of Oz   [your turn]  23:32, 18 March 2011 (UTC)


 * Here is our relevant article on degaussing TVs. It's sounds like that might be the issue. I'm sure a Google search for that phrase will yield many more unofficial remedies. When this has happened to me in the past it's been solved by removing (or increasing the distance to) the nearby device which was putting out the offending EM interference (usually a speaker or subwoofer). The TV/monitor will then usually degauss itself after a short while. i.m.canadian (talk) 12:36, 19 March 2011 (UTC)
 * Thanks for that info. --   Jack of Oz   [your turn]  09:23, 20 March 2011 (UTC)

I tried the above suggestions, but nothing worked. I checked in with the vendor of the set top box, and he said they do put out a magnetic field, but way too weak to cause the problem I was having; so moving it around was never going to have any effect, which it didn't. For as long I can remember, we've always turned the set on and off using the hand-held remote. It's never been turned off at the set itself since the day it was installed. He suggested we try that; this should trigger the internal degaussing mechanism. I turned it off, waited a while, turned it back on again, and hey presto! problem gone. It's been on for about 6 hours since then, and no sign of the problem coming back. But if it does, I'll know what do now. Kudos to User:Thincat, who provided the answer above ("TVs should demagnetise the mask when they are switched on") but I didn't interpret it properly. This feedback is brought to you as a public service. --  Jack of Oz   [your turn]  09:56, 9 April 2011 (UTC)

Lead and church roovs
We hear a lot in the news about lead being stolen from church roovs and sold for scrap, and I've always wondered why lead is used in their construction. Roovs on other buildings don't have it, or do they? TheRetroGuy (talk) 23:16, 18 March 2011 (UTC)
 * It is used because lead is very resistant to corrosion, and therefore helps in making a roof that won't leak. It is avoided nowadays in many places because where you have lead, you have a risk of lead poisoning.  (The spelling is "roofs", by the way.) Looie496 (talk) 23:54, 18 March 2011 (UTC)
 * Rooves is also accepted. But not roovs.  --   Jack of Oz   [your turn]  01:25, 19 March 2011 (UTC)
 * I would have said that rooves was rather more acceptable than roofs. Anyway, sheets of lead make a good waterproof casing on a shallow-pitched roof. This page shows some examples including the modern substitution of stainless steel (harder to work, but harder to remove). The dome of St Paul's Cathedral in London is covered with lead too - there isn't much else you could use. Alansplodge (talk) 02:39, 19 March 2011 (UTC)
 * "Hoof/hooves, Calf/calves, Roof/rooves, Dwarf/dwarves, Thief/thieves, Sheaf/sheaves, Leaf/leaves, Wolf/wolves, knife/knives, Half/halves. Life/lives. Wife/wives, Shelf/shelves"  Or just be trendy and add an "s" rather than the older "ves." Be that as it may, U S Grant's house in Galena, IL supposedly still has the original lead covered roof from when he lived there circa 1860.  The lead probably forms an oxide and remains stable for a long time. The copper has greater tensile strength. (Or maybe it was "terne," a tin-lead mixture over steel; it has been many years since I was there). Edison (talk) 02:51, 19 March 2011 (UTC)
 * Roofs is standard American. Meriam-Webster doesn't include rooves. (And Tolkien made up dwarves, instead of the standard dwarfs. "a piece of private bad grammar") Rmhermen (talk) 03:55, 19 March 2011 (UTC)
 * Roofs is also the usual plural in modern British English (ever since Milton & Dryden), but rooves is an acceptable alternative here (I was taught it but don't use it). I can't compete with Ulysses Grant, but I am sitting under a roof with lead that is 120 years old and still mainly in excellent condition (most of it will last another few hundred years) except where grit washed down with rainwater has eroded it.    D b f i r s   08:11, 19 March 2011 (UTC)


 * At the risk of spoiling the show by getting back on topic. UK church roofs (Collins Dict.) have the original lead replaced because it is legally required. This is to maintain the integrity and historical accuracy of the building under the Planning (Listed Buildings and Conservation Areas) Act 1990, which applies in the UK. The risk of lead poisoning to users of the church or casual passers by is vanishingly small. Modern buildings, by and large, don't use much lead because there are better materials now available that weren't available when the majority of churches were built and these buildings are not subject to the strict retrospective planning and conservation laws that prevail in the UK. Richard Avery (talk) 08:06, 19 March 2011 (UTC)
 * Agreed, but it depends on the Listed building status of the church in question. Obviously some are allowed to replace lead with other materials - see the whowlettandsonsltd.co.uk link above. Alansplodge (talk) 20:59, 19 March 2011 (UTC)
 * In the UK, if the roof has something sticking out such as a dormer window or chimney, lead flashing is used to provide a waterproof seal at the junction of the roof and the protrusion. There are more modern materials around, but they tend to be used on more modern buildings. However, I know of lead flashing being used round new-build dormer windows. --TammyMoet (talk) 09:59, 19 March 2011 (UTC)

Lead ore is widely found and its softness and low melting temperature 600°C have made it easy to work with since ancient times. Cuddlyable3 (talk) 11:33, 19 March 2011 (UTC)


 * Thanks everybody. TheRetroGuy (talk) 14:10, 19 March 2011 (UTC)
 * Many rooves use copper, which turns green from verdigris. 92.24.178.214 (talk) 23:29, 19 March 2011 (UTC)
 * Which is often considered a design plus. And copper is frequently stolen as well, in the US, can't speak of other countries.   Corvus cornix  talk  18:30, 20 March 2011 (UTC)