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August 7

Katha from acacia catechu tree

This material Katha is used in making paan masalas and used for other medicinal purposes.For manufacturing Katha rooms are build where specified temperature are required and there are two rooms which are used to produce the final material. First Room:Material in liquid form(water content 60percent) is brought in Al/Steel Containers and stored for 10days at 1.5Deg.C and 90percentRH and the liquid get thicker as the water content is removed by providing air circulation with refrigeration.

Second Room:Material from the first room is converted in biscuits form(water content 44percent) and are brought in Al/Steel trays and stacked in racks and stored for 4days at 7Deg.C and 65percentRH and the water content is removed by providing air circulation with refrigeration.

• QUESTIONS:

To find the refrigeration load the following is required by me.

1. What is the specific heat of Katha before freezing and after freezing.
2. What is the freezing point of Katha.
3. What is the Latent Heat of Fusion of Katha. —Preceding unsigned comment added by Mgkhanduja (talk • contribs) 00:08, 7 August 2010 (UTC)

I am going to guess the answer, and that your substance is gum acacia. The specific heat will be largely due to water, so it will be proportional to the fraction of water. If you are spending a lot of money on this, you may not want to rely on Wikipedia volunteers! The solidification point will be closely related to the water content, but it will freeze at close to 0 degrees if a large amount of water is present due to the molecular weight of the gum being high. Graeme Bartlett (talk) 00:39, 7 August 2010 (UTC)

Uphill running

At the risk of asking a stupid question, do rivers ever run uphill? Maybe there are some quirks of geography such that some rivers have points at a higher elevation further along their course? Stanstaple (talk) 00:34, 7 August 2010 (UTC)

I think only for a short distance of a few meters, if they have built up a bit of speed, it could push up and over a bar across the river. Normally if there was a higher elevation it could split the river into two streams flowing away from the high point. Graeme Bartlett (talk) 00:43, 7 August 2010 (UTC)

If they have to, they will make a deep pool (as many feet deep as feet uphill it has to run), until it reaches the level where it can flow over the hill. But it would probably erode away the streambed before that happens. Or it could go around it. --Chemicalinterest (talk) 01:10, 7 August 2010 (UTC)

Yes it is, and no they don't. Cuddlyable3 (talk) 03:32, 7 August 2010 (UTC)

Sorry to be a pedant, but you seem to have answered a question I didn't ask :) Stanstaple (talk) 01:14, 8 August 2010 (UTC)

Lakes are formed when rivers have to flow uphill. --Chemicalinterest (talk) 16:55, 7 August 2010 (UTC)

It's not a stupid question at all, it's just a bit poorly defined. We all know water runs downhill, but does that mean that no part of the river downstream could possibly be higher than any part of the water upstream? Of course not; waves may lap higher, rocks or other obstructions may cause a bit of the stream to shoot upwards, and so on. What you need to keep in mind is that the water, like everything else, is being acted on by gravity. That's what forces the water to typically run downhill. However, just as we can still lift our leg despite gravity pulling it down, so too can a river roll over rocks and other obstructions. When the current of the stream is no longer strong enough to overcome gravity, then the water will pool, forming a lake. Now, on a slightly different tack, I recall reading an article in Discover magazine some years ago where water was indeed forced to run up an incline (though we're talking about a few drops of water, not a river here) after being placed on a surface that had been sprayed with an extremely hydrophobic substance in a gradient so that the most hydrophobic area was lower than the less hydrophobic area. The water was sufficiently repelled by the material that it would rise against the force of gravity. Obviously that's a special case scenario, but it illustrates that there are more forces at play on a river than simply gravity and they need to be factored in rather than giving the mostly true but incomplete and inaccurate reply of "No, water doesn't run uphill." You may also be interested in the phenomenon of the tidal bore where water is indeed forced uphill - and against the river's current to boot! Matt Deres (talk) 18:39, 7 August 2010 (UTC)

Similarly to the part about waves and lapping over obstructions, consider a waterfall. Often some of the water hitting the bottom splashes back up. If it happens to fall into a suitably shaped cavity, most of it may splash up, although such a configuration will be subject to heavy erosion and will tend to be eliminated by this long before the waterfall is. Anyway, this is river water moving temporarily uphill. --Anonymous, 04:52 UTC, August 10, 2010.

When a river turns, the water on the outside of the bend will be significantly higher than on the inside of the bend. Edison (talk) 19:30, 7 August 2010 (UTC)

Have a look at this discussion from January[1] (scroll down to "Engineering Question -Flipper's Ditch"). The gist of it is that there are a number of famous places where water seems to flow uphill, but it's an optical illusion. Alansplodge (talk) 13:04, 8 August 2010 (UTC)

You may also be interested in reading about the Hydraulic ram which uses the kinetic energy of flowing water to force some of it uphill to a considerable height. These devices are still in use for supplying domestic water in some areas. Dbfirs 20:30, 8 August 2010 (UTC)

Drinking diethyl ether

The diethyl ether page mentions that peasants in Silesia used to drink it. It doesn't say very clearly how dangerous that is, and neither does the reference link. Would a shot glass of ether do an adult any lasting damage? 86.140.52.244 (talk) 00:44, 7 August 2010 (UTC)

I had a good dose of it as an anesthetic as a child and it stank quite a bit, and also led to vomiting. Is there no beer, wine, whiskey, gin, rum, vodka, mead or hard cider available in the region where folks supposedly drink the stinky and nauseating stuff? Drinking diluted ether sounds akin to the dangerous practice of huffing volatile compounds. Edison (talk) 02:40, 7 August 2010 (UTC)

Hundreds of years ago in Europe, basically everything found in nature that was not described as immediately poisonous was being consumed. I don't see why Polish peasants didn't drink a highly diluted form of it. Remember that pure ethanol is quite dangerous to drink, but billions do drink it diluted anyways. hello, i'm a member | talk to me! 02:45, 7 August 2010 (UTC)

I'll drink to that!Edison (talk) 02:52, 7 August 2010 (UTC)

There is an article on this on the Polish Wikipedia (w:pl:Eteromania). If you really need further information I can translate it for you. --Ouro (blah blah) 07:41, 7 August 2010 (UTC)

I'd be interested, but I don't actually need to know. Just curious. The reference for our article here says the Polish government tried to ban ether drinking, but doesn't make it clear if that was for medical, fiscal (ie loss of alcohol taxes) or moral reasons. 86.140.52.244 (talk) 17:12, 7 August 2010 (UTC)

It sounds like we need an English article on the topic, can you make one? Etheromania but this may be a neologism! Graeme Bartlett (talk) 22:54, 7 August 2010 (UTC)

I would suggest Addiction to ether consumption or Addition to ether or something similar. I will be happy to create it, but I do not have the time today. Tomorrow? Tuesday? --Ouro (blah blah) 09:44, 8 August 2010 (UTC)

My cousin used to work for the Hudson Bay Company at a trading post in arctic Canada. They weren't allowed to sell hairspray to some of they locals as they were likely to drink it. My father once told me that there was a problem in WWII with RAF groundcrew making merry with the engine coolant. Some will drink anything they can get their hands on. Alansplodge (talk) 12:56, 8 August 2010 (UTC)

what is this plant?

It lives in my backyard in CA. It's got dandelion-like yellow flowers (but somewhat smaller and more compact, like that of the yellow starthistle, except more sunken in), and when the plant "dries up", the flowers turn into little irritating spikes that stick on one's clothing and skin. It's fairly green and leafy when not "dry". hello, i'm a member | talk to me! 03:44, 6 August 2010 (UTC)

It could be catsear or hawkweed or hawksbeard, any of which is commonly confused with true Dandelion. --Jayron32 03:48, 6 August 2010 (UTC)

It is aster-like, but it has leaves that are elliptic, almost ovate, kinda roundish-long. They are dark green, and they fall off when the plant dries and the little spikes form. It those that those spikes are the fruit (seeds); they don't seem to fly away with the wind...they stick on to whomever touches it. hello, i'm a member | talk to me! 04:21, 6 August 2010 (UTC)

Any help?...I would really like to get rid of it, but I need to know what the plant is called. hello, i'm a member | talk to me! 02:42, 7 August 2010 (UTC)

Can you take a picture of it? You're not really giving enough information. Looie496 (talk) 03:21, 7 August 2010 (UTC)

Sickness

I was recently sick and I had a really weird dream, it was like I was high, but of course I would never do something like that. Anyway, has any research been done on the phenomenon of the vivid, distorted dreams you have when you're sick? Is ther a wikipedia article? —Preceding unsigned comment added by 76.199.154.44 (talk) 02:45, 7 August 2010 (UTC)

Though it may not have to do with being sick, Lucid dream is pretty interesting. wiooiw (talk) 02:49, 7 August 2010 (UTC)

Did you have a fever? It is sometimes associated with nightmares but it can cause other weird dreams. wiooiw (talk) 03:11, 7 August 2010 (UTC)

It can also cause delirium, which could be relevant. --Tango (talk) 03:47, 7 August 2010 (UTC)

If you were delirious in a lucid dream would you be "just dreaming" or could you be experiencing the feelings you would actually get if you are delirious? -- Sjschen (talk) 04:15, 7 August 2010 (UTC)

I've had both fever dreams and lucid dreams, and they are not at all similar. Lucid dreams tend to be characterized by being in control of the situation, whereas the fever dreams lean heavily towards nightmares and hallucinations. Viriditas (talk) 10:06, 7 August 2010 (UTC)

I concur. Fever dreams are quite distinct. When I've had fever dreams, part of the problem was that I seemed to slip in and out of them and into wakefulness (kind of like an inverted night terror, I guess), so that reality and the dream state became even more blurred than normal. There can be times where you're completely unsure whether you're dreaming or awake and hallucinating. Lucid dreams are exactly the opposite of that: you become aware of the dream and take hold of it. You also get a completely different feeling upon waking. Fever dream may be a bit of a misnomer, though; I've experienced them with no fever at all, but where I was sick enough (usually a severe sore throat) that it interrupted my sleeping. That interruption of the sleep cycle is probably part of the cause for the so-called fever dream. Matt Deres (talk) 15:27, 7 August 2010 (UTC)

To the OP: Sometimes sick people will take diphenhydramine, and I'm curious if the OP was exposed to it. It can produce very strange (and even frightening) dreams at low dosages. Viriditas (talk) 10:06, 7 August 2010 (UTC)

No need to bring drugs into the picture, the reality of fever dreams is quite well established. Looie496 (talk) 16:54, 7 August 2010 (UTC)

The only reason I brought it up, is because in my experience, the nightmarish quality of a diphenhydramine dream was almost identical to the fever dream I had as a child. I doubt anyone has ever made this connection before, so have at it. Viriditas (talk) 01:46, 8 August 2010 (UTC)

Viriditas raised a good point. Before I had ever heard of "tussing" I once experienced hallucinations from taking too much dextromethorphan cough suppressant, and for several days I assumed that it was due to my high fever at the time. -- 119.31.121.72 (talk) 06:05, 8 August 2010 (UTC)

I have experienced psychic effects from diphenhydramine (Benadryl) but I don't specifically recall an effect on dreams. More like generalized anxiety.

On the other hand I had a long sequence of some of the oddest, most exhausting dreams one time on prednisolone, which I was prescribed for a really bad case of poison oak. It was a six-day pack where you take six pills the first day, five the second day, and so on. I got it at about 4 in the afternoon so I had to take six pills in a fairly short time span. --Trovatore (talk) 20:24, 8 August 2010 (UTC)

I've had electric blanket induced fever dreams, every time i've accidentally slept with my electric blanket on too high.. Unfortunately it's really uncomfortable and annoying to wake up in the middle of the night drenched in sweat, otherwise I'd do it all the time just for the trippy dreams.. Vespine (talk) 04:58, 9 August 2010 (UTC)

Scientific names of hybrid species

We know the scientific names are unique name for a species. eg. Magnifera indica is scientific name for common mango. But what about the scientific names of the hybrid species? How their names are determined? e.g. We see many different kinds of mangoes in the market, are all of them are Magnifera indica or they have some different name? From where can we find exact name of a particular species? Thanks! Shivashree (talk) 04:11, 7 August 2010 (UTC)

Known hybrids are named with "×" between the genus and the species terms. For instance, loganberry is Rubus × loganobaccus and grapefruit is Citrus × paradisi. Of course if people did not know it was a hybrid they sometimes gave it the normal biological classification name Genusname speciesname instead of Genusname × hybridname. It helps to remember that ideas like genus, hybrid, and species can be a bit blurred depending at what you are looking at. -- Sjschen (talk) 04:27, 7 August 2010 (UTC)

Thanks, Sjschen, for your quick response. But is there any database from where we can get the scientific names of the species in our neighborhood? Shivashree (talk) 06:01, 7 August 2010 (UTC)

Why don't scissors work upside-down?

Just curious why scissors don't work upside-down or for left-handed people? --68.102.163.104 (talk) 05:07, 7 August 2010 (UTC)

Well, there are scissors specifically made for us left handed people. And for it not working upside down, your probably holding it incorrectly. Maybe if you try to hold right handed scissors upside down in your left hand or viceversa it might somehow make it easier to cut. wiooiw (talk) 05:19, 7 August 2010 (UTC)

As for why left/right handed scissors are harder to use for other handed people... Whether you realize it or not, when you use scissors, you are imparting a slight sideways force on the blades which brings them together not only in the up and down direction but the side to side direction as well. When you use a pair of opposite handed scissors, you are making the blades push away from one another. Take a look at our scissors article where it shows left and right handed scissors. You'll notice the blades are opposite of one another. Dismas|^(talk) 05:31, 7 August 2010 (UTC)

Turning an object upside down doesn't change its parity. Scissors don't have an "upside down" except for those with shaped handles. You can learn to use right-handed scissors with your left hand, or left-handed scissors with you right hand. You just need to pull with your thumb and push with your fingers. At first, this seems unnatural, but you soon get used to it. Dbfirs 09:01, 7 August 2010 (UTC)

I think by "upside-down" the OP means holding a pair of scissors upside down so that the blades are on the side of your fist where your pinkie is. --173.49.16.4 (talk) 18:25, 8 August 2010 (UTC)

Oh, I see. (I misunderstood because I normally use scissors horizontally.) Yes, that would enable right-handed scissors to be easily used by a left-handed person (and vice versa). It doesn't change the parity of the scissors, but it does reverse the natural pressure applied by thumb and fingers. Many modern scissors, when new, will cut without requiring any side pressure at all, so they can be used by either hand if held very loosely. Dbfirs 20:13, 8 August 2010 (UTC)

I'm left handed - it's nothing to do with exerting pressure, I can do that with perfect ease using right-handed scissors. The actual problem is that the top blade obscures your view of the line you are trying to cut along. When a right handed person uses right-handed scissors, the top blade is on the right side of the line they are cutting along - so they can easily see where they are going. When a left handed person does that, the blade itself prevents you from seeing exactly where the scissors are cutting - so you can't cut with any degree of precision. Also, many modern scissors have fancy-shaped handles designed to relieve the pressure on the hand while cutting - and those are pretty much physically impossible to use in your left hand. SteveBaker (talk) 03:07, 11 August 2010 (UTC)

I saw this 50% chance dwarfism gene on some medical documentary years ago. What's that condition called?

On this documentary years ago, I watched about how if a certain pair of parents conceive, there was a 25% chance that the baby would be a healthy one, with a normal height. Then there was a 50% chance that the baby would become a dwarf; have pretty stunted growth.

Then there was a 25% chance that the baby would have some kind of non-survivable condition. The diagram shown while the narrator was speaking this, was a negative picture of a fetus. That condition was called some ominous Latin-sounding name that I have of course long-forgotten.

Would someone please refresh my memory on this? Thanks. --Let Us Update Wikipedia: Dusty Articles 09:11, 7 August 2010 (UTC)

You are probably thinking about achondroplasia, which is the most common type of dwarfism. Since it is autosomal dominant, each affected parent has one normal copy of the gene (call it "A") and one that isn't working properly (call it "a"). If you draw out a typical Aa x Aa punnett square you'll see that the different combinations are AA (normal), Aa and aA (both affected), and aa (severely affected, likely lethal). --- Medical geneticist (talk) 11:50, 7 August 2010 (UTC)

Thanks, Geneticist. I guess you hit the nail! You said "aa" is likely lethal. Has anyone ever survived with "aa?" Where can I read articles on "aa" survivors? (Articles with pictures preferred.) --Let Us Update Wikipedia: Dusty Articles 05:23, 8 August 2010 (UTC)

Life is a lethal condition ;)

For the "aa" genotype I should have written "likely perinatal lethal" to be more precise, although there are case reports of such individuals living several months. It is certainly safe to say that being homozygous for the common achondroplasia mutation results in early mortality, typically during infancy, due to severely restricted lung capacity and other problems such as hydrocephalus. There is variability in how long different individuals have survived, likely depending on the degree of medical intervention early in life (see example here), but it would be hard to imagine someone surviving into childhood or adulthood with homozygous achondroplasia. Can I say that it has never happened? No, but it is exceedingly unlikely. So, "lethality" really boils down to "when" a particular condition is likely to be lethal. --- Medical geneticist (talk) 11:28, 8 August 2010 (UTC)

musical memory

Unlike books, it's hard for me to forget the lyrics and the notes of a song...I have about 2500 songs on my iPhone. When will I reach my "capacity"?

Too much remembering is a problem, because for some really good songs I'd really like that experience of listening to an awesome song for the first time. John Riemann Soong (talk) 09:38, 7 August 2010 (UTC)

Here's an interesting read [2]. It doesn't particularly address your question of where your limit is though. I'm not sure anyone can answer that. Regards, --—Cyclonenim | Chat  11:00, 7 August 2010 (UTC)

There is no known limit on human memory, but there is senescence and lifespan that more than makes up for it. Viriditas (talk) 13:48, 7 August 2010 (UTC)

I think the mind can also create new tunes out of bits of other songs in the memory, but not everybody does that. ~AH1^(TCU) 15:19, 7 August 2010 (UTC)

Many people find that they can remember the "hook" lyrics of even the most popular songs of their youth, but the rest of the lyrics are just bum-de-dum-dum. If you remember the lyrics of 2500 songs you may have unusually good recall. Edison (talk) 19:27, 7 August 2010 (UTC)

I remember the full lyrics of most songs that I listen to (fully). There are songs that I mentally "endure" so I don't remember them as well. John Riemann Soong (talk) 18:05, 11 August 2010 (UTC)

John, do you have eidetic memory? Viriditas (talk) 01:43, 8 August 2010 (UTC)

Why do you think he does? I have about 10,000 songs with lyrics and I'm fairly certain I know the lyrics to most if not all of those songs. It's different to eidetic/photographic memory, where you can remember, say, every word in any book you read. Regards, --—Cyclonenim | Chat  13:58, 8 August 2010 (UTC)

Do you mean that you remember all the lyrics of every song, for example can you recall all the lyrics of XXX song, or do you mean that when you are listening to a song, you know the lyrics that are coming up? Like Cycloneim I have almost 10,000 songs and whilst I can remember the lyrics of a song as it plays, there's no way that I could recall the lyrics from cold. Similarly I find it strange that I can nearly always remember whether I've heard a song before or not, but cannot remember all the songs I've ever heard, and that must include ~20,000 songs. Smartse (talk) 16:35, 8 August 2010 (UTC)

Also take a look at music-related memory. WHAAOE! ~AH1^(TCU) 18:40, 8 August 2010 (UTC)

skin

why does paint dries my skin out —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 11:37, 7 August 2010 (UTC)

Taking an uneducated guess: The paint covers your skin and absorbs any moisture already on the surface. Regards, --—Cyclonenim | Chat  23:03, 7 August 2010 (UTC)

Could the paint either be hydrophillic, absorbing the water away from your skin, or hydrophobic, repelling any surface moisture away from your skin? ~AH1^(TCU) 18:39, 8 August 2010 (UTC)

Processing multiple voices

Is it possible, maybe through training, for a person to be able to listen to 2 or more simultaneous messages ? I know I can quickly switch between processing the two messages, but they become jumbled, im wondering if this could change though training.. would be an interesting skill to have :) —Preceding unsigned comment added by Rowen121 (talk • contribs) 19:35, 7 August 2010 (UTC)

We have an article on this, dichotic listening. It is frequently used in psychology experiments studying subliminal perception. Looie496 (talk) 20:59, 7 August 2010 (UTC)

Identifying trees

Hi. Could someone help me identify the following two trees please? Thanks! Randomblue (talk) 20:01, 7 August 2010 (UTC)

I don't know the first, but the second looks like some sort of plum. Looie496 (talk) 20:56, 7 August 2010 (UTC)

The seed pods of the first are very similar to those of ash. Brammers (talk/c) 23:12, 7 August 2010 (UTC)

I agree the first is an ash and the second is possibly a gean. I say possibly because the fruit seems a bit big for a wild cherry and it may just be a rogue hybrid plum. The context of the discovery would help and a description of the size of the tree, colour and texture of the bark. Richard Avery (talk) 07:01, 8 August 2010 (UTC)

The first is an ash, almost certainly a Common Ash. The second is certainly a member of the Prunus family; maybe a Bullace or Damson? A bullace is a wild damson, smaller and less sweet. Alansplodge (talk) 12:47, 8 August 2010 (UTC)

Soldering iron tip compatibility

Are soldering iron tips interchangeable or are they manufactured to ensure that they only work with certain brands/models of iron? ----Seans Potato Business 20:35, 7 August 2010 (UTC)

I don't think they are deliberately manufactured to be incompatible, and some brands will be interchangeable, but in general, tips fit a particular design, and there are so many different designs that you are unlikely to find a matching one by a different manufacturer. Some designs (such as "Weller" - apologies for the advertising. I'm sure that others make a similar product.) have tips designed to be quickly swapped for different applications, but full irons are so cheap in some outlets that it is hardly worth replacing tips. Dbfirs 07:33, 8 August 2010 (UTC)

Wikipedia has an article Soldering iron (also Soldering gun can be of interest). Reasons for changing soldering iron tips are: they become eroded by solder (bare copper tips erode faster than iron-plated tips), different sizes of tip are suited to particular jobs, and some temperature-controlled soldering irons, e.g. from Weller a brand of Cooper Tools, allow operating temperature to be set by a thermostatic part in the tip. In general the tips are not interchangeable between brands of iron. (OR) The looped tip of a soldering gun is not much more than a bent copper wire, and that can be used as an emergency replacement.Cuddlyable3 (talk) 14:56, 8 August 2010 (UTC)

Evolution

What proof is there for evolution/Darwinism? Isn't it just an atheist myth created to insert anti-religion propaganda into the public school system? What evidence is there to support Darwinian dogma? --138.110.206.99 (talk) 20:38, 7 August 2010 (UTC)

Wikipedia already has plenty, see evolution and related articles like Introduction to evolution and references and links thereof Nil Einne (talk) 20:51, 7 August 2010 (UTC)

But the Holy Bible says that Darwinism is an atheistic lie. --138.110.206.99 (talk) 21:08, 7 August 2010 (UTC)

It actually doesn't say that (which would make sense, given that Darwinism and naturalistic evolution more generally are concepts that came much later in time). I have a hard time believing you're not just trolling us, though. If you really want to know about evolution, we've already referred you to a place to start. If you're just here to state what opinions you already have, that's going to get your question deleted. Let me phrase it one other way: if you are here to learn something, we're happy to help; if you're here to convince us of something, you'll be politely (or perhaps impolitely) shown the door. --Mr.98 (talk) 21:20, 7 August 2010 (UTC)

If you already know it's a lie, why are you asking us? --Tango (talk) 21:37, 7 August 2010 (UTC)

I'll try to restrain my "fire breathing" now. Most people believe in evolution (not Darwinism, he just thought of a hypothesis and someone else promoted it) because they do not like what the Bible says about creation. Evolutionists have many proofs; some in favor of evolution, but most not in favor. This is what I believe. This is what most people believe: The Bible is a story written by man. Evolution is fact. Religion is just an evolutionary mishap. This is a WP:NPOV statement, although it is slightly biased. --Chemicalinterest (talk) 00:36, 8 August 2010 (UTC)

That someone else was amongst others, T H Huxley, aka Darwin's Bulldog. Not to be confused with Richard Dawkins, aka Darwin's Rottweiler. 62.56.60.192 (talk) 08:41, 8 August 2010 (UTC)

I don't know if anyone has ever done a survey on why people accept evolution, but it seems more likely people accept it because of the overwhelming weight of evidence in support of it, and its overwhelming support by biological scientists not because of what they may think about what the bible says about the creation. The fact that it makes more sense to them then other suggestions, like creationism probably helps for a few but that isn't quite the same thing. In any case, I have no idea why you believe most people in China or India or many other countries will give a damn about what the bible says about creation, they probably aren't even aware of what it says.

Also in many countries most people still have some sort of religious belief. These may not be strong, but are still enough that the person describes themselves as having religious beliefs. Even here in NZ, hardly an extremely religious country most people still described themselves as Christians as of the most recent census, see religion in New Zealand. While some of these people may describe their religious beliefs or the bible as an 'evolutionary mishap' it would seem odd that a large number would. (They may believe the bible has been modified by humans or isn't a reliable source for the word of god or more likely perhaps just not really care about the bible.) Finally a large number of religious people, including those who still believe the bible is the word of god have no problem accepting evolution.

Nil Einne (talk) 07:14, 8 August 2010 (UTC)

The Bible does not mention evolution; not surprising as the Bible was completed around (IIRC) 200AD. However, evolution, plate tectonics, astronomy, and several other areas of the natural sciences conflict with a literal reading of Genesis, and thus are heretical to those who believe the Bible is the literal inerrant word of God. For a Christian perspective of evolution, see http://community.berea.edu/scienceandfaith/essay05.asp. Some of the major Christian churches, including the Roman Catholic Church, accept evolution, and consider Genesis to be allegorical. CS Miller (talk) 09:55, 8 August 2010 (UTC)

I think we are being trolled. This question is suspiciously similar to another asked on January 26, 2010. See HERE. Dolphin (t) 12:53, 8 August 2010 (UTC)

Only the first sentence of the OP's question is reasonable. The second sentence reveals a political agenda motivating the question. Wikipedia has an article Creation-evolution controversy. The rules of this Ref. Desk forbid this and previous attempts to exploit it as a forum for the controversy. Cuddlyable3 (talk) 14:39, 8 August 2010 (UTC)

Thanks I seemed to remember a similar question before but didn't have any luck finding it so decided a brief and to the point link to our articles would be best. In case anyone hasn't noticed, both the OP and J4V4 are interested in Pokémon and Quebec. Nil Einne (talk) 15:33, 8 August 2010 (UTC)

See Theistic evolution and day-age creationism. All peleontological and modern zoological evidence shows that evolution is a fact as well as a theory. ~AH1^(TCU) 18:35, 8 August 2010 (UTC)

Building an insulated cabinet

I want to build an insulated cabinet out of wood with a 40W heater inside. It's for keeping fermenting bins in, which suprisingly enough I don't think we have a wiki article on! I was under the impression that a Cavity_wall mainly acted by trapping air and creating a Thermal break but after reading the articles I'm guessing that I should really have some sort of insulating material in the cavity? 3 questions:

Does the size of the cavity make much difference to the insulation, eg. 3mm vs 10mm?

Is there a cheap material that I could use to fill the cavity that's readily available?

Would lining the inside of the cabinet with aluminium foil be more important than insulating material?

Thanks, Mike 87.112.198.91 (talk) 21:07, 7 August 2010 (UTC)

If you want to go as cheap as possible you can use crumpled newspaper. But polystyrene foam could be good as long as you don't let it get too hot. Al-foil is good on the inside of the newspaper. Graeme Bartlett (talk) 02:32, 8 August 2010 (UTC)

Air is a perfectly good insulator, but you need something in a large gap to prevent convection currents from carrying heat from inside to outside, hence the crumpled newspaper or polystyrene foam (any old random pieces from packaging material will suffice). Another alternative would be rock wool used for loft insulation. Dbfirs 07:22, 8 August 2010 (UTC)

Aluminium foil will mainly help at higher temperatures, at fermenting temperatures ordinary insulation will work better (that's if you have to choose between them). You can buy foam sheets with foil already on them. They are not expensive, and they hold their own shape so I think that would be the easiest to install. I wouldn't use rock wool or fiberglass insulation unless you had a way to isolate it from the cabinet. It's not good to touch it or let it get into food. To your question about the size of the cavity I'm not sure. Do you mean just an empty space? And are wondering if a bigger space is better? Obviously if the space is filled with insulation then a bigger one is better, but if it's just empty it's not so obvious. Insulation is all about the empty space, but it's not about having a larger empty space - it's about having more of them (i.e. space, wall, space, wall). Ariel. (talk) 19:11, 8 August 2010 (UTC)

Yes, I was thinking of a fully enclosed cavity. Don't get rock wool or bits of polystyrene in your drink! The foam sheets will be much cleaner if you can afford them. Dbfirs 21:58, 8 August 2010 (UTC)

Thanks all! I'll price up some of the foam sheets, if they're cheap enough I'll use them :-) Mike 87.112.198.91 (talk) 10:55, 9 August 2010 (UTC)R

I hope you'll name your first successful brew in honour of the Ref Desks :-) . (87.81 posting from . . .) 87.82.229.195 (talk) 14:11, 9 August 2010 (UTC)

I will name my next batch 'Ref Desk Tramp Juice'

If you are putting a heater inside, be sure to consider fireproofing. Newspaper is extremely flammable. In fact, many forms of insulation are extremely flammable. Fiberglass batting, while more expensive, may be worth the cost, if you plan to leave this heater and cabinet unattended (again, leaving this cabinet unattended also increases fire risk, so plan carefully). Nimur (talk) 19:58, 9 August 2010 (UTC)

Thanks for the warning but I should be OK. It's only going to be a 40W heater and the heater should be at least 40mm away from the inner skin of the cabinet :-) Mike 87.112.198.91 (talk) 21:27, 9 August 2010 (UTC)

August 8

North Pole?

How come there is no volcanoes in the North Pole? When was the last time that a continent sat on the north pole?--68.116.113.157 (talk) 00:41, 8 August 2010 (UTC)

There are lots of places with no volcanoes. There is nothing special about the North Pole in that respect, so I don't see why there needs to be a reason. This map from the late Jurassic period (so about 150 million years ago) shows land very close to, if not actually at, the pole (it's hard to tell from the image). That seems to be the most recent time there was any land near the pole. You can see the recent (last half a billion years or so) changes in the placements of continents in this animation: File:TectonicReconstructionGlobal.gif. --Tango (talk) 00:59, 8 August 2010 (UTC)

Volcanos (see article) occur where tectonic plates meet. There are no tectonic plate borders at the North Pole. Cuddlyable3 (talk) 14:19, 8 August 2010 (UTC)

Are you sure? I was going to say the same but then I came across File:Plates tect2 en.svg...a line goes off the top of the map and comes down the other side. Which suggests to me it passes pretty close to the North Pole. I realise flat maps can't properly illustrate a spherical(ish) globe, but... Vimescarrot (talk) 16:18, 8 August 2010 (UTC)

That map doesn't actually show the north pole. The north pole on that projection is a horizontal line infinitely far above the map, if I'm recognising the projection correctly. There is no way to know what that plate does north of the boundary of the map just by looking at that map. There is a whole chunk of the plate missing. --Tango (talk) 16:55, 8 August 2010 (UTC)

The source page says "Mollewide projections show the entire globe in one view, but are distorted significantly along the margins of the globe". Looie496 (talk) 17:50, 8 August 2010 (UTC)

You misunderstand. The map Vimes links to doesn't show the North Pole. The map I embedded certainly does, otherwise my answer wouldn't have made any sense. --Tango (talk) 17:54, 8 August 2010 (UTC)

On the other hand, there are plenty of Arctic volcanoes, especially in Iceland. ~AH1^(TCU) 18:31, 8 August 2010 (UTC)

Do we have any images of the major plates superimposed on a more modern projection, or something that preserves the curve a little better? (I'm also surprised by how weird it is to see a map like this centred over the Americas, but I don't think it would be reasonable to ask for one that matches my own expectations) Is Vimes's link a Mercator projection? The British Isles looks huge on it, and Africa very small. 82.24.248.137 (talk) 19:32, 8 August 2010 (UTC)

The boundary between the North American and Eurasian plates actually passes very close to the north pole, but it's difficult to find a picture that shows this properly. However I haven't seen anything that indicates volcanic activity at that part of the junction. Looie496 (talk) 20:03, 8 August 2010 (UTC)

You want the Gakkel Ridge, which passes pretty close to the pole and is an active (if extremely slow) spreading center - that article also has a useful image. Mikenorton (talk) 07:19, 10 August 2010 (UTC)

The Neurons or the synapses

Does it improve a person's memory or intelligence to have many neurons or is it in the synapses or the way that the neurons send the signals that is responsible for why some people have better memories than others? I believe Kim Peek (Rain man inspiration) was said to not have the corpus callosum, and it is in theory that some believe because of this his brain found a way of connecting around that at a superfast speed and that is what is responsible for his memory. Also, can the neurons or the way signals are sent be changed, I ask because I watched this documentary that had a guy from Enland who after an epilectic seizure when he was three he started to get this incredible memory and brilliance for numbers and on the same documentary there was a kid who got hit in the head with a baseball as a kid and ever since that he too had an afinnity to memorize dates and so on? —Preceding unsigned comment added by 70.136.158.173 (talk) 01:12, 8 August 2010 (UTC)

Also, could the size or shape of the brain have anything to do with it? (In the MRI taken of a woman who has memorized every day of her life from 1980 on and others like her there bains were slightly different shape and they were all left-handed.)

Most neuroscientists believe that memory is stored by changing the strength of synapses, so the total number of synapses sets a limit on the amount of memory the brain can store. But this is only one factor: an effective memory depends on a whole range of systems for formatting, storing, and recalling memories. It's like in a computer memory is stored in little magnetic things, but if you just throw a pile of magnetic things on the floor, you don't get a usable memory system -- it all has to be organized properly.

It is very common for autistic savants to have extraordinary memory for details. Most don't have a missing corpus callosum, so I doubt that that has anything important to do with it. The stuff about signals connecting around at superfast speed is just nonsense. Basically we don't know where those extraordinary memories come from -- it clearly involves a higher level of brain organization than we yet understand. Changes in brain shape might be relevant, or they might not -- we just don't know yet. Looie496 (talk) 02:26, 8 August 2010 (UTC)

The hippocampus definitely does something uncertain to do with memory. Experienced taxi drivers (who can remember complicated maps) have enlarged ones, as the article mentions. 81.131.58.136 (talk) 02:56, 8 August 2010 (UTC)

Are the parts and even the strength of the synapses continually growing? Like for example our bones even though we stop growing and reach our full height our bones are still constantly rebuilding themselves and continue to go through a process? —Preceding unsigned comment added by 71.156.2.13 (talk) 03:52, 8 August 2010 (UTC)

There is quite a bit of evidence that synapses change continuously. A synapse is only a single signal channel, so they don't get more complicated over time, but they do get stronger or weaker. Among other things, Giulio Tononi's theory of sleep proposes that synapses steadily strengthen over the course of each day, and then weaken when we are asleep -- there is substantial evidence to support this. Looie496 (talk) 04:52, 8 August 2010 (UTC)

Does chemical/hormones have anything to do with the strength or weakness of the synapse and or the neurons for that matter? —Preceding unsigned comment added by 71.137.245.165 (talk) 12:48, 8 August 2010 (UTC)

Absolutely. In fact, nearly every psychoactive drug exerts its effects by making some group of synapses either more or less effective. There are a small number, such as caffeine, that act on neurons by non-synaptic mechanisms, but the great majority act on synapses. There are also internal chemicals, such as norepinephrine, that act at least partly by modifying the strength of synapses in specific brain pathways. Looie496 (talk) 17:42, 8 August 2010 (UTC)

See Eidetic memory and neuroplasticity. ~AH1^(TCU) 18:27, 8 August 2010 (UTC)

The thing is that our brains definitely have a finite capacity - it's probably comparable to the size of the hard drive in your computer. But memories aren't (usually) stored with perfect fidelity. I can recall my wedding day from 25 years ago - but I have almost zero memory of anything that anyone said to me on that day - other than a few snatches of the speech my father gave at the reception. Because the brain has finite capacity - and we didn't evolve to live to be 100 years old - we must eventually be forgetting things at about the same rate that we learn them.

But we don't do that by totally forgetting one entire year of our lives for every year we live. Our more distant memories become fuzzier - and less important things get erased in order to keep a choice few of the most important. It's as if we're continually summarizing less important (typically, older) information in order to make room for new, sharper memories. I think it's clear that the more amazing the savant's abilities are, the more mentally crippled they seem in other regards. Those who are able to memorize (by rote) unbelievable amounts of raw data - may well have damaged the part of the brain that is responsible for summarizing and discarding trivia. The brain has a spectacular storage capacity - it's not at all surprising that one could memorize a million digits of PI or a thousand books - but perhaps these people are losing information that the rest of us would find essential to daily life? It's hard to know because if such a person is incapable of (for example) managing interpersonal relationships or (maybe) holding down a job - we can't easily tell if that's because they are unable to remember some important class of data that relates to those more normal activities. SteveBaker (talk) 01:21, 10 August 2010 (UTC)

What tends to happen is that people with extraordinary event memory have difficulty generalizing -- they know all the facts but can't spot the patterns in them, can't see the forest for the trees if you will. Thus for most tasks they actually do less well than people with poorer memory. One of the nicest descriptions of the phenomenon is in Alexander Luria's classic The Mind of a Mnemonist. Looie496 (talk) 23:02, 10 August 2010 (UTC)

When is a heat sink necessary for a 7805 voltage regulator?

Hello! I'm a (newbie) hobby electrician. I'm planning on using an AC adapter that outputs 9V 210mA connected to a 7805 voltage regulator for my project. How do I know if a significant amount of energy will be wasted as heat? The circuit will be in operation mostly 24/7. When is a heatsink connected to the regulator required? The circuit will be working at room temperature. I think part of the difficulty I'm having understanding how the voltage regulator will work is because I've only worked with DC from batteries, and learned that when 9V is connected with a 1KΩ resistor in series to an ammeter, the reading will be 9mA, but I don't know why the AC adapter's specs show 9V at 210 mA. I would think (probably wrongly) that 9V would output 9A because of the ammeter example I gave. I'd also appreciate any help on understanding this now that I'm moving on from working with AA batteries. Thank you!--el Aprel (^facta-_facienda) 02:21, 8 August 2010 (UTC)

The regulator will reduce the voltage by varying its resistance. The current flowing through times the voltage drop will turn into heat. The AC adapter rating is just the maximum, so you have to know how much current your circuit will consume, If it only takes 10mA then no heat sink will be needed, but the full 200mA dropped by several volts, will need one. Graeme Bartlett (talk) 03:15, 8 August 2010 (UTC)

At risk of straying into wikibooks/wikiversity territory, you need the output voltage of the bridge rectifier. This will be the RMS of the step-down transformer you are using. Then take (Vin - Vout) / Iout. This will give the power drop across the voltage regulator. The voltage regulator's datasheet will give a maximum operating temperature. Say it is 70°C, this is fairly typical. Given a room temperature of around 30°C (a bit on the high side), the voltage regulator can not be more than 40°C above ambient. Say the transformer is at 12V AC. RMS is 17V DC. The drop across a 9V regulator is 8V (check the maximum input voltage, but they are normally around 50V). 8V * 210mA is 1.68W. That is 0.04W/°C or 25°C/W, assuming the heatsink is in free air. In enclosed cases you need a bigger heatsink (higher value for W/°C, smaller for °C/W), if you are using fan-cooling then a smaller heat sink is needed. CS Miller (talk) 11:04, 8 August 2010 (UTC)

You haven't mentioned the current draw of the load for the 7805. Once you know the load current, the rest is quite straightforward. As Csmiller hinted above, small unregulated wall-wart power supplies have very poor load regulation, that is, their output voltage at no-load can be more than twice their rated output voltage (i.e., example, 20V at 0 mA, 15V at 20 mA, but 9V at 210 mA). In this example, if the load draws 20mA, the 7805 will sink (15V - 5V)*20mA = 200mW, (9V-5V)*210mA = 840mW, etc. Alternatively, you can just use an off-the-shelf regulated wall-wart. If it's output is not clean enough, add passive RC filters.East of Borschov 18:12, 9 August 2010 (UTC)

I think you mean "If its output has too much ripple,...", and adding a passive RC filter will reduce the voltage to below the nominal regulated value i.e. Vout = Vreg - R Iout. Cuddlyable3 (talk) 19:48, 12 August 2010 (UTC)

Maximum knowledge

Albert Einstein experienced mind/brain expansion.

Omniscience is impossible. For instance, the uncertainty principle states that we can not simultaneously know an elementary particle's position and momentum. So what is the maximum level of knowledge that can be attained, and is there any realistic measure of attaining it?--220.253.219.83 (talk) 04:24, 8 August 2010 (UTC)

The maximum knowledge that can be obtained is the amount of knowledge that our brains are capable of holding. That's an infinitesimal fraction of the information in the universe, so it doesn't really make sense to talk about obtaining it. The information in a teaspoon of water is vastly beyond our ability to comprehend. Looie496 (talk) 05:04, 8 August 2010 (UTC)

I think you may be misunderstanding the uncertainty principle. We often say things like "we can not simultaneously know", but that is misleading. The correct understanding is that particles do not ever have both a fixed position and momentum. It's not a statement about our lack of knowledge. It is an expression that trying to assign momentum and position to everything is inherently futile because those properties do not exist. A hypothetical omniscient deity could know everything there is to know, and still wouldn't know both position and momentum, because the universe simply doesn't allow particles to ever have well-defined values for both. Personally, I don't see any objections in quantum mechanics to a deity having omniscient knowledge of the present and past. However, the principle of wavefunction collapse (as presently understood within our limited knowledge) would seem to imply that even a deity would never be able to uniquely predict what would happen in the future, since quantum mechanics inherently involves randomness. Dragons flight (talk) 05:26, 8 August 2010 (UTC)

Unless the deity is the source of the randomness. You are assuming a deity that lives in the universe, but the deity could be the universe. i.e. the deity is to the universe as you are to a thought in your mind. Meaning each and every particle and interaction in the universe is specifically "animated" by the thoughts of the deity. Ariel. (talk) 07:59, 8 August 2010 (UTC)

No. All of those are the same as saying quantum mechanics is wrong, because the events would no longer be truly random. You can either say the universe isn't random (because the deity guides it, etc), or you can say the universe is random and future outcomes aren't known till they occur, but you can't have it both ways. Of course, a deity could certainly make a predestined universe appear random to beyond our ability to ever tell the difference, but that's not the same as saying the universe actually is random. Dragons flight (talk) 08:19, 8 August 2010 (UTC)

What's the difference? From a physics point of view I mean, not a philosophical one. If it's random beyond our ability to tell the difference, if there is no physical test or ability to tell otherwise, then it is random. The Equivalence principle works exactly the same way: Since there is no way to tell the two forces apart, they are the same. Ariel. (talk) 08:30, 8 August 2010 (UTC)

Collapseless interpretations of QM don't present this problem --Atemperman (talk) 05:36, 10 August 2010 (UTC)

Information (not exactly the same as knowledge, but close enough) is strongly tied to energy. It takes energy to manipulate and store information. See Limits to computation and google for "Ultimate physical limits to computation" for more exact numbers. Another limitation is the speed of light - you can not know about anything not within your light cone. Additionally as you store more information the size of your "brain" gets larger - eventually it gets large enough that it takes a long time (because of the speed of light) to retrieve information from the other "side" of it. This greatly limits the speed at which you can think. (So you can know a lot, but not be able to think fast, or know less and think faster.) There is no direct answer to your question since you did not specify what is doing the "knowing", but maybe what I wrote was interesting anyway. Ariel. (talk) 07:59, 8 August 2010 (UTC)

Infinite knowledge may or may not be impossible, as infinite knowledge of information would be impossible, but knowledge is distinct from information. There are also ways that ordinary people use to increase knowledge to much higher levels (ie. mystical self-hypnotic mind-expanding introspective spiritual experience), but not in a way that true omniscience could be achieved at any given point in time. The electron conundrum is likely connected to the quantum zeno effect. Knowledge cannot be quantified, and therefore may have little to do with the possible interconnections between neurons and synapses (~∞). As for the deity as universe argument, this is called pantheism. Also, it would be possible for an omnipotent being to create a door he cannot open. All the being has to do is make the door so that it is impossible to open at a specific time, but make it able to be opened when he decides it can. ~AH1^(TCU) 18:14, 8 August 2010 (UTC)

Even forgetting quantum theory and uncertainty and things like the speed of light limitations on information transfer - this is a tricky problem. Ultimately, you need N bits of storage to store N bits of information. If the smallest imaginable item of information (let's say the spin on a particular fundamental particle) could be stored in the most compact way imaginable (which would probably be using the spin of a remarkably similar fundamental particle!) then the very best you could possibly do would be to store all of the information about half of the universe using the other half of the universe to store it!

That is a crazy upper-limit - gathering and maintaining the information would require machinery comprising some very large fraction of the universe! Also, history is a part of knowledge. If you used 90% of the stuff of the universe to store information about the other 10% then you'd only be able to store that information for 9 instants in time...which is a pretty crappy kind of history! It is a little tricky though - you might argue that you could store half of the information about the universe onto the other half - then you'd now know everything about 100% of the universe because the two halves are now identical. You might also argue (classically) that if you know everything possible about some chunk of universe at some particular instant in time - then you could extrapolate forwards and backwards in time to know the state at some arbitary time in the past or future. Aside from the quantum and chaos theory issues with that - there is now another problem. The half of the universe that you're storing the information on is affecting the half that it's trying to store...that means that the progress of your extrapolation calculations will affect the future in such a manner as to make your extrapolations incorrect.

We could also get into annoying philosophical arguments about what it actually means to "know" something. For example, we know the equation for calculating PI to an arbitary number of digits. Does that mean that we "know" what all the digits of PI are? Well, maybe...I don't know the 30th digit of PI - but I could probably find it out soon enough to be useful - so it's not much of a stretch to say that I "know" it. But suppose I wanted the googol'th digit? That might take my computer a billion years to calculate it...I don't think anyone would claim that they know what that digit is. If (as in the hypothetical case of using one half of the universe to store the information about the other half) my computer cannot retrieve the information faster than I can go out and measure it again - is there even any point in storing it. If I want to know the albedo of the 3rd moon of the 4th planet orbiting alpha centauri - but that information happens to be stored in a part of my computer that's 100 light years away - then it's easier to send out a probe a few light years and measure the albedo than it is to ask the computer to fetch the information for me. Do we "know" something if the cost to retrieve that knowledge takes longer than collecting the knowledge itself?

This is an interesting question to think about - but you're definitely not going to get a single good answer!

SteveBaker (talk) 00:44, 10 August 2010 (UTC)

Tetra Fish Fins

Do the fins of a tetra fish grow back? My wife and I have a 150 gallon aquarium filled with all kinds of tetra fish,and the other day we noticed that one of the smaller fishes front fins were nibbled on and the fish is flapping constantly.We seperated the fish from the pack and we were wondering if the fishes fins will ever grow back? If so how long? —Preceding unsigned comment added by 173.105.146.216 (talk) 10:04, 8 August 2010 (UTC)

Added new section header Rojomoke (talk) 10:27, 8 August 2010 (UTC)

Generally the consensus seems to be yes they will grow back. [3] 87.102.23.179 (talk) 11:48, 8 August 2010 (UTC)

Yes, they grow back; they could not reach the same size as the original fins. 82.59.69.48 (talk) 13:13, 8 August 2010 (UTC)

SOx cooling atmosphere

This recent article at Ars Technica mentions [4] (from a report it covered) : ..result of a stronger cooling effect from sulfate aerosols.. (I'm not particularily interested in the article or conclusions/methodology)

I was wondering if any figures were available on the cooling effect of 'sulphate aerosols' - ie what magnitude of effect has/will have Flue-gas desulfurization had/will have on the worlds temperature, particularily the isolated effect of not adding sulphur to the atmosphere - not the overall balance taking into account burning coal. Thanks.87.102.23.179 (talk) 11:46, 8 August 2010 (UTC)

Are you wondering if it might be better to leave in the sulfur in order to cause global cooling? It's not worth it. The acid rain is far worse, To get rid of CO2 we need those plants, and acid rain kills them. Ariel. (talk) 05:18, 9 August 2010 (UTC)

A few weeks ago the paper-edition New Scientist had an article claiming that the last few decades' efforts to reduce the UK's sulphate emissions to lessen the acid rain impact on Scandinavia had (i) had little impact on the acidity, because most of it (82%?) comes from Scandinavia itself, the North Sea or other parts of continental Europe, and (ii) had resulted in a measurable increase (0.8C?) in the UK's average temperature due to the lessening of the aerosols' cooling effect. Unfortunately the article seems not to be on the NS website. (87.81 posting from . . .) 87.82.229.195 (talk) 14:06, 9 August 2010 (UTC)

I did see an article (can find it now) that said that desulphurisation caused local warming. I was wondering if this was an reasonably established fact or not. I've not seen or heard this side effect mentioned in the news etc..

As to Ariel's comment - I'd be interested in a enviromental cost benefit analysis - but a proper referenced one I could read for myself.87.102.35.46 (talk) 15:31, 9 August 2010 (UTC)

You would have to inject the sulfur into the stratosphere to cause cooling and prevent acid rain. ~AH1^(TCU) 22:42, 9 August 2010 (UTC)

St. Bernard dog

Why the St. Bernard dog is not recognised by the italian ENCI (Italian National Kennel Club)? 82.59.69.48 (talk) 13:10, 8 August 2010 (UTC)

That's a tough one for us to help you with since all the info is in Italian. Try asking on the Italian wikipedia. Also I'm not sure this question belongs in the science desk. Ariel. (talk) 05:23, 9 August 2010 (UTC)

The Italian national kennel club "Ente Nazionale della Cinofilia Italiana" (ENCI) is a member of Fédération Cynologique Internationale that recognizes the St. Bernard as a Molosser in Group 2, Section 2. Cuddlyable3 (talk) 12:43, 9 August 2010 (UTC)

Thanks. Ok, I will try to ask in the italian Oracolo too. I know, the question is border line here (is about a bureaucratic issue regarding applied biology), if you want to move it please feel free to do that, though the major experts in this matter should be here. Ok, so undirectly the ENCI recognises the St. Bernard; but why doesn't the breed appear in ENCI list? —Preceding unsigned comment added by 87.11.129.247 (talk) 16:57, 9 August 2010 (UTC)

wave analyzers

which analyzers we will use to check the frequency of the wave having frequency above 20GHZ? Is it spectrum analyzer or not —Preceding unsigned comment added by Balachandramovva (talk • contribs) 17:12, 8 August 2010 (UTC)

You can buy oscilloscopes that reach that frequency. Is that what you are asking? Ariel. (talk) 05:28, 9 August 2010 (UTC)

Here and here are manufacturers of frequency counters that cover the 0 to 40 GHz frequency range. Here is a 20 GHz spectrum analyzer. Cuddlyable3 (talk) 12:35, 9 August 2010 (UTC)

Yoplait has a fat-free Greek yogurt.

I thought a big part of Greek yogurt was its high fat content. What's the point otherwise? 67.243.7.245 (talk) 18:45, 8 August 2010 (UTC)

Taste? Regards, --—Cyclonenim | Chat  19:45, 8 August 2010 (UTC)

Our Strained yoghurt says that what's called 'Greek yoghurt' typically just means some form of strained yoghurt. So I would guess taste as Cyclonenim mention and texture would be a big reason why some may want 'Greek yoghurt'. Our article also notes "strained yoghurt is a traditional food in the Middle East and South Asia, where it is often used in cooking, as it is high enough in fat not to curdle at higher temperatures" which may be what you're referring to and it indeed seems likely that advantage would be lost but I guess quite a number of people aren't choosing it so it doesn't curdle at higher temperatures as you have presumed Nil Einne (talk) 19:51, 8 August 2010 (UTC)

For the record, several companies offer fat-free frozen yogurts, in vanilla and other flavors (I prefer vanilla). They do not lack in taste, but I suppose Greek yogurts might. 2Ð ℳǣ$₮ℝʘ ^{talk, sign} 23:06, 8 August 2010 (UTC)

We have fat-free greek yogurts in our freebie kitchen at work - the actual yogurt doesn't taste of much - but they come with actual fruit at the bottom - so step #1 is stirring them up! SteveBaker (talk) 00:21, 10 August 2010 (UTC)

How does a car's wheels get out of alignment?

How does a car's wheels get out of alignment? My understanding is that driving over potholes and hitting the curb hard when parking can both cause alignment problems. What are some other causes? Also, what exactly happens when something causes your car's wheels to be misaligned? Is something in your car deformed? --173.49.16.4 (talk) 18:53, 8 August 2010 (UTC)

Joining the front steering wheels of a car there is a significant length of mechanism consisting of push-rods, threaded adjustors, gears, bearings and dampers. This mechanism is relatively light in weight. Impacts to the steering wheels, such as impacts with potholes and the curb, can cause movement in the threaded adjustors. However, much of the drift in the alignment is caused by wear of the tires. Even a change in tire pressure from the pressure that existed during the last alignment can necessitate re-alignment. Wear in the gears, bearings and dampers in the steering system also contribute to drift in the overall alignment. Deformation of the body of the car is not a contributor to misalignment, except if the car has been involved in an accident. There is a little information at Wheel alignment. Dolphin (t) 23:31, 8 August 2010 (UTC)

fridges

What is the reason some people say you shouldn't close a fridge door when it's turned off? Do modern fridges overcome this? 82.43.88.151 (talk) 19:53, 8 August 2010 (UTC)

No, this applies to all fridges and freezers of every vintage. It is almost impossible to avoid the growth of moulds and bacteria at room temperature, but normal circulation of the air with an open door helps to prevent excessive growth. Cleaning out the fridge with bicarbonate of soda will also help. Dbfirs 20:52, 8 August 2010 (UTC)

If you leave it open for a long while, and let it dry out it's OK to close it later. Ariel. (talk) 21:49, 8 August 2010 (UTC)

Yes, I agree that the damp conditions encourage the growth of nasties, but I'd still prefer to clean the inside before closing the door. Dbfirs 21:54, 8 August 2010 (UTC)

So to clarify, because I'm still confused, the reason people say the door shouldn't be closed is... to stop mold growing? 82.43.88.151 (talk) 22:16, 8 August 2010 (UTC)

Yes, and bacteria. If you open a fridge door after it has been closed for a long time at room temperature and without drying out as Ariel suggests, you will notice a horrid stink of decay (the bacteria) and a musty smell from (usually black) patches of mould (mold in the USA) which can also attack the plastic and rubber seals of the fridge. Dbfirs 23:03, 8 August 2010 (UTC)

Additionally, if a refrigerator is being removed for disposal, the door is normally removed for safety reasons, so that playing (hiding) children won't get trapped and suffocate. Kingsfold (Quack quack!) 16:40, 9 August 2010 (UTC)

I agree, it seems as though no matter how carefully you clean/disinfect the inside of an empty refrigerator - if you unplug it and close the door then it will stink horribly within just a couple of days - and pretty soon you'll see black mold spots. If you clean it and leave the door open, it'll be fine.

Moisture trapped inside the fridge seems to be the problem - even the smallest amount of nutrient - plus darkness and moisture produces the perfect place for mold to thrive. Remember, the refrigerator doesn't just chill the air - it also dehumidifies it. The inside of a (running) refrigerator is a spectacularly dry place - and mold can't survive without moisture.

SteveBaker (talk) 23:56, 9 August 2010 (UTC)

Energy

If capillary action raises the center of mass of the water in the tube, where does the energy come from? 76.68.247.183 (talk) 19:55, 8 August 2010 (UTC)

I think it might come from the Gibbs free energy, but perhaps you should wait for an expert to confirm or refute this. The article doesn't make easy reading! Dbfirs 20:53, 8 August 2010 (UTC)

It comes from potential energy. It takes energy to "unstick" the water from the surface of the tubes. Water, by it's nature, is at a slightly higher energy. When it sticks to something it goes to a lower energy. Note that tall trees do not use capillary action to raise the water. Instead they evaporate some water from the leaves on the top, and the lower pressure "pulls" water up from the roots. Ariel. (talk) 21:41, 8 August 2010 (UTC)

Are you sure? I'm sure I've seen trees more than 34 feet high! Dbfirs 21:52, 8 August 2010 (UTC)

We do, of course, have an article on the subject: Transpirational pull. If I'm interpreting it correctly, it is basically a combination of transpiration and capillary action (or something closely related to it) that makes it work. --Tango (talk) 22:37, 8 August 2010 (UTC)

(ec)Yes, I meant to say don't just use capillary action. There is a third mechanism they use as well, but I don't remember what it is. I'll try to look it up later. Ariel. (talk) 22:54, 8 August 2010 (UTC)

Yes, it is impossible for "lower pressure" to "pull" water more than 34 feet high, so the main effect must be capillary, as stated in the article. There may also be some osmotic pressure. I am still awaiting an expert to check on my Gibbs claim, though Ariel referred to "water energy" which might be the same thing. The OP was asking where the potential energy comes from as the water rises through capillary action. Dbfirs 22:52, 8 August 2010 (UTC)

It's not something I know a great deal about, but our article says Gibbs free energy is the ability to do non-mechanical work. Lifting something against gravity is mechanical, isn't it? The osmotic pressure you refer to is root pressure, which is a factor in some circumstances. --Tango (talk) 23:19, 8 August 2010 (UTC)

Root pressure is feeble - it is only able to move water ~30cm upwards. The differences in water potential between the roots + shoots is a driver for water flow however. Smartse (talk) 22:31, 9 August 2010 (UTC)

As Dbfirs above suggests the energy comes from the interaction between the water and glass - which is favourable in terms of energetics - ie it can do work.87.102.23.179 (talk) 01:07, 9 August 2010 (UTC)

No, no, no! NO free energy! Let's not even contemplate the possibility for a nanosecond! You can't make perpetual motion machines using surface tension - although plenty of very stupid people have tried!

This is no different from taking a stretched elastic band - releasing it and asking where the energy came from to contract it. The energy was put into the elastic band when you stretched it - it contracted in order to get into a lower energy state by releasing that energy. It happened because the rubber molecules like being coiled up - it takes energy to uncoil them - and they give up energy when you let them coil back up again. Same deal here. Water molecules like being stuck to glass more than they like being stuck to other water molecules. Not all molecules are like that...Mercury, for example prefers the company of other mercury atoms than it does glass and has an upside-down meniscus and tends to sink down a capilliary tube rather than rushing up it. It's all to do with hydrogen bonding and Van der Waals forces.

The water (when it's at the bottom of the tube) is in a higher energy state than when it's at the top of the tube - because (like a stretched rubber band) it is in a configuration it doesn't want to be in. It actually loses energy in moving up the capilliary tube...even though it's moved upwards against gravity (and therefore has more gravitational potential energy). It gave up more energy than that by clinging to the glass than it lost in the upward motion - just like the rubber band un-stretching.

Once the water is stuck to the glass, you have to add energy to get the water to go back down to the bottom of the tube again. That's why cars need windshield wipers. The raindrops like being stuck to the glass - you have to put energy into wiper blades to get persuade it to fall off.

You can't extract energy from the height of water in the capilliary tube because you have to use energy to unstick it from the glass. Kinda like pulling a magnet off of your refrigerator.

SteveBaker (talk) 23:46, 9 August 2010 (UTC)

There is, of course, such a thing as free energy. --Trovatore (talk) 23:50, 9 August 2010 (UTC)

Of course it's free as in speech, not free as in beer. --Trovatore (talk) 00:36, 10 August 2010 (UTC)

It was "free" as in "available" (like a stretched band), not "free" as in "perpetual motion", but I agree with Steve's analysis. There is an official recommendation to remove the word "free". Perhaps our article should just be "Gibbs energy". It's probably not a very helpful concept here because it is more usually applied to chemical reactions rather than to physical attractions between molecules, but it does emphasise the fact that all substances have internal energy in their atoms and molecules. Smartse's water potential link is better, but I suspect that matrix potential alone is not sufficient. Does the tree also input energy to create osmotic differentials to implement capillary action in stages? There is a limit to the height attainable in any capillary tube (otherwise we run into Steve's objection of perpetual motion). Dbfirs 02:08, 10 August 2010 (UTC)

No, I think the article should stay where it is. IUPAC and similar organizations can recommend all they want; we should change when common practice actually changes, not because some body made something "official". --Trovatore (talk) 02:24, 10 August 2010 (UTC)

OK. I understood the meaning of "free", and I don't suppose many non-specialists read the article anyway. I agree that we should reflect general usage. Dbfirs 02:41, 10 August 2010 (UTC)

Yes, it is "free energy" in the technical sense (not in the perpetual-motion machine sense). Understandably, this nomenclature is confusing (and reeks of violation of the second law of thermodynamics) - but that is a matter of language-use. No actual physicist or chemist thinks "Gibbs free energy" comes from nowhere. It's "free" in the sense that it is not inherently bound to the internal process that is moving energy from a source to a sink; but energy still has to come from the source. Nimur (talk) 18:07, 10 August 2010 (UTC)

No one said it came from nowhere. I was just needling Steve on the no free energy comment. --Trovatore (talk) 18:31, 10 August 2010 (UTC)

Jumbo Jet vs. Mortal

Is it possible for a human being to move a Jumbo Jet by pulling it ? -- Jon Ascton  (talk) 21:03, 8 August 2010 (UTC)

Never mind a jumbo jet (by which I guess you mean a 747) which is old (1997) news, the record appears to be for a 416,299 pounds (188,830 kg) CC-177 [5] [6]. Nil Einne (talk) 21:19, 8 August 2010 (UTC)

It depends only on the friction and nothing else. It does not depend on how heavy the jet is. I think jets have reasonably low friction on the wheels but I'm not sure. Ariel. (talk) 21:39, 8 August 2010 (UTC)

(ec) For an object on wheels, you just need enough force to overcome the friction in the bearings, etc., which isn't necessarily that great. Once it is moving, it will accelerate very slowly, so you need to be very strong if you want it to move a significant distance in a reasonable amount of time, but moving it isn't actually that hard. The difficult bit is probably getting enough grip with the ground so you don't just slip backwards rather than pulling forwards - if you apply too much force, your shoes will just slip against the ground, regardless of how strong you are. --Tango (talk) 21:41, 8 August 2010 (UTC)

The difficulty in moving a rubber-wheeled vehicle, such as a jumbo jet, comes not from friction in the bearings which is very minor. The difficulty is deforming the rubber in the tires. Rubber is not perfectly elastic so it displays elastic hysteresis. Much more energy is absorbed by the tires as they reshape during rolling than is absorbed by friction in roller bearings.

It is useful to contemplate moving a locomotive on steel wheels, or better still moving a ship through water. In the era prior to power-driven tugboats, ships had to be moved up and down rivers, and maneuvered to and from the dock, by rowing boats powered by nothing more than half a dozen men with oars. So large vehicles can be moved by manpower, but it doesn't help to be impatient! Dolphin (t) 22:56, 8 August 2010 (UTC)

If a human were in a space suit in orbit holding onto the International Space Station and a space shuttle, he/she could move them quite easily by pushing or pulling, since there is no friction. The speed would start out ever so slight and increase to a meter per second in under 4 minutes, if the person pushed with 500 Newtons (112 pounds force). A jumbo jet standing on the runway would require considerable force to start it moving on a perfectly level surface, probably more than anyone with normal strength could exert. Exerting that same force for a considerably longer time would likely leave the jumbo jet right where it started. Edison (talk) 03:37, 9 August 2010 (UTC)

How do you expect your astronaut to produce a force of 500N without separating from the space station? It's like the point I made above about your shoes slipping against the ground, but taken to the extreme. --Tango (talk) 03:50, 9 August 2010 (UTC)

Easy, the SS and Shuttle would be, say, 5ft apart and the astronaut would crouch between them and push orthagonally to move them apart: obviously the scenario of moving them "horizontally" relative to one another could not work using only surface friction, though foot and handholds on which to engage might enable a horizontal component. (87.81 posting from . . .) 87.82.229.195 (talk) 13:57, 9 August 2010 (UTC)

But you can only do that for a second or two. You can't do it for 4 minutes to get them up to 1 m/s (assuming constant acceleration, they would be 120 metres apart by the end of the 4 minutes). --Tango (talk) 16:43, 9 August 2010 (UTC)

Many adult humans of normal strength could exert a 112 pound force for 3 or 4 minutes. Lots of adults who should weigh 130 pounds actually weigh 240 and engage in all sorts of activities. People sometimes carry heavy burdens long distances, or push or pull heavy things. Edison (talk) 19:20, 9 August 2010 (UTC)

You can only do it for a second or two because after that the spacecraft will be out of reach. --Tango (talk) 22:17, 9 August 2010 (UTC)

I have some ambivalence about calculations versus perceived reality. I would not think that an angry astronaut could attack the space shuttle or space station and destroy it with his bare hands. But it seems that if he had his feet hooked around a stanchion on the ISS, and held a rope attached to the shuttle, he could in a few minutes generate enough relative velocity to crash them together disastrously. And if he started to push or pull with 500 Nt force, would folks on the 100000kg space shuttle feel the "jerk?" Edison (talk) 02:07, 10 August 2010 (UTC)

This image seems relevant. --Sean 15:57, 9 August 2010 (UTC)

It's obviously possible - there are lots of videos of it being done ([7] for example). The problem of moving a plane is basically four-fold:

1. Overcoming static friction. Most surfaces produce more friction when they are stationary than when they are moving. Once you get them moving (even very slowly), static friction goes away.
2. Overcoming regular dynamic friction. Traditionally, weight plays a big part in the amount of friction there is - but we're not talking about one surface rubbing against each other - this is rolling friction which is mostly due to tyre deformation and such like. There is a certain amount of traditional friction in the bearings of the wheels - but that's really very small.
3. Overcoming aerodynamic drag. This is a non-problem at the super-low speeds we're taking about - planes are also really well streamlined!
4. Producing an acceleration. Acceleration equals Force divided by Mass - so mass is really important here. But acceleration is another non-problem. No matter how small the acceleration you are able to produce, the speed will gradually build up until all of the force you're able to supply is overcoming friction and drag. At the low speeds that a person could reasonably pull at, drag is negligable - so once you've got it moving, friction is 100% of the problem - and it doesn't change much with speed...so once the plane is moving, you can gradually speed up until you're pulling the plane pretty quickly.

Since the sticktion is bigger than the friction - this becomes only a matter of whether you can get the thing initially rolling. Once it's moving the distance and speed are largely irrelevant.

I used to know someone who did a charity jumbo-jet pull with about 20 co-workers (they got sponsorship from the airline for the distance they could pull it...which was kinda silly given the physics of it all...once they got it moving, they could have pulled it around all day!) The biggest concern of the company that runs these events was mostly concerned over people being run over by the plane once it was moving! The other little 'gotcha' is that you always assume they are doing this on level ground - but my friend said she could see that they'd picked a very gentle slope to do it on...so gentle it was hard to spot - but she spilled the bottle of drink she was carrying and could see the water rolling away ahead of her efforts to pull the plane. It only takes a very gentle slope to overcome friction on something like a plane. So this is very easy to fake - and since everyone is doing this for publicity and for a good cause, they all have incentive to cheat if they can get away with it. So we have to be super-careful about what we do and don't believe.

SteveBaker (talk) 23:15, 9 August 2010 (UTC)

An additional help is that the tires on aircraft are inflated to a much higher pressure then on a car. Something like 150-200 psi if I recall, so tire deformation should be lower. Googlemeister (talk) 13:33, 10 August 2010 (UTC)

No, the weight is higher, so the deformation is about the same. Pounds of plane / PSI of tire = Square inches of contact patch (not including what the sidewall strength of the tire holds). In theory a tire is a circle with a contact area of zero. So the contact patch represents deformation of the tire. This is true in a car as well. Ariel. (talk) 17:08, 10 August 2010 (UTC)

I wouldn't be surprised if they overinflate before one of these stunts. APL (talk) 00:33, 13 August 2010 (UTC)

Food poisoning, even after cooking?

Can dead bacteria and viruses or other related compounds cause food poisoning, even after the food has been thoroughly cooked?

To put it differently, can food that's extremely old always be made safe for human consumption by merely cooking it? ☯  Zenwhat (talk) 21:43, 8 August 2010 (UTC)

I think our article on Bacterial toxin answers your questions. I don't advise trying it out on yourself. Dbfirs 21:50, 8 August 2010 (UTC)

Putting it simply, it's not just the biological agents that cause food-borne illness, but also the toxic chemicals they leave behind. These chemicals can remain after cooking, so no, cooking old food doesn't make it safe.--el Aprel (^facta-_facienda) 00:15, 9 August 2010 (UTC)

I don't know why you felt the need to repeat what had already been said...Anyway, there are also bacteria/viruses that can survive normal cooking. The longer the food has been left, the more of these bacteria there will be...obviously. 90.195.179.60 (talk) 01:46, 9 August 2010 (UTC)

Your snotty tone is uncalled for, and a reference is always helpful. Edison (talk) 03:18, 9 August 2010 (UTC)

It hadn't already been said... A link had been provided to a page that included the information, but it can help to provide a summary here. --Tango (talk) 03:52, 9 August 2010 (UTC)

Another relevant article is Danger zone (food safety).. Some food can be far from "spoilt" but no amount of cooking will make it safe to eat if it has been in the "danger zone" for a few hours. Vespine (talk) 04:43, 9 August 2010 (UTC)

It's not food poisoning, and has nothing to do with how old the food is, but there's no way known to destroy prions and leave the food intact. Paul (Stansifer) 05:09, 9 August 2010 (UTC)

A good example is ciguatera. From the article: "Ciguatoxin is very heat-resistant, so ciguatoxin-laden fish cannot be detoxified by conventional cooking." Viriditas (talk) 05:17, 9 August 2010 (UTC)

Thanks for the help and the example! ☯  Zenwhat (talk) 21:49, 9 August 2010 (UTC)

Salmonella bacteria can often affect cooked meat, while Bovine spongiform encephalopathy requires 48 hours of cooking at 500C(?) to get rid of the prions. ~AH1^(TCU) 22:39, 9 August 2010 (UTC)

August 9

What manner of turtle is this?

I saw this turtle about a quarter mile away from the Olentangy River in Columbus, Ohio, on a rainy afternoon in June. What kind of turtle is it? Thanks. —Preceding unsigned comment added by 98.28.19.62 (talk) 00:36, 9 August 2010 (UTC)

Apalone mutica, the smooth softshell turtle, I think. Deor (talk) 01:01, 9 August 2010 (UTC)

Conservation of matter argument for Climate Change and Alternative energy?

Before the Great Oxygenation Event (GOE) about 2.4 BYA there was no, or very little, free oxygen in the atmosphere. Now there is 78% nitrogen, 21% oxygen and 0.0387% carbon dioxide. A portion of the carbon that used to be in the atmosphere is locked up in fossil fuels. Do we have any idea how much carbon is locked up as fossil fuel? I used to think that burning fossil fuels is effectivley undong the GOE, this seemed to me a good argument for alternative energy which didn't really rely on whether or not you "believe" in global warming. However, the articles about fossil fuels indicate that our FF reserves are mostly 300-600 million years old. Does this mean there is a whole lot of GOE Carbon locked up somewhere other then fossil fuel? Obviously "current" life (forests etc) has some carbon locked up, but as a percentage is that a big protion or a small portion? Or a tiny portion? How much fossil fuel IS there available to burn? And if we burn it all, or a good portion, can't we predict how much more co2 there will be in the atmosphere? Or are things like the ocean carbon sink too hard to predict? Even if we don't "undo the entire GOE" isn't increasing the CO2 level by 100 or 200 parts per million considered quite bad? So what would happen if we got to 0.1% or 0.5% atmospheric carbon dioxide? Is that really so "unlikely" at our current pace of emission? Sorry i know this is a bit all over the place.. Vespine (talk) 05:17, 9 August 2010 (UTC)

Well, the GOE was an oxygen event, not a carbon event. But more relevantly, the account above leaves out major parts of the carbon cycle. Most of the Earth's carbon is in the mantle, and this source gets into the atmosphere via volcanic activity. Also, atmospheric CO2, because it is acidic, reacts with rock via a process called weathering to give rise to carbonates. These carbonates end up on the sea floor eventually, and sooner or later the sea floor gets subducted and takes the carbon back into the mantle. All this is very slow, but it's fast enough to have recycled the entire sea floor several times since the GOE. The bottom line is that the carbon cycle can't be understood by looking only at atmospheric carbon, fossil fuels, and the biosphere, it's also necessary to take into account mantle carbon and carbonate rocks.

Regarding how much fossil fuel there is, the amount of oil is limited, but the amount of coal is huge, hundreds of years of supply even if we burn it as fast as we can. Looie496 (talk) 05:50, 9 August 2010 (UTC)

The burning of fossil fuels does lead to a measurable decrease in atmospheric oxygen. This is one of several pieces of evidence that let us know that the increase in atmospheric CO₂ is, without any reasonable doubt, anthropogenic. However, if you look at the stoichiometry, it takes one molecule of O₂ to produce one molecule of CO₂. We have burned fossil fuels worth very roughly about 200 ppm of CO₂ (about half of which is in the atmosphere, the other half has gone into other sinks). 200 ppm is 0.02%, so the effect on oxygen levels is relatively small. --Stephan Schulz (talk) 07:06, 9 August 2010 (UTC)

Are you saying that this 200 ppm ATM reduction of O₂ has been measured? -- 119.31.121.66 (talk) 12:36, 9 August 2010 (UTC)

No. As far as I know, we have reliable records for atmospheric O₂ only since the mid 1980s or so. But since then, decrease in oxygen has been largely in inverse lock-step with anthropogenic CO₂ emissions (there are some subtleties because CO₂ is much more soluble in sea water than oxygen is). --Stephan Schulz (talk) 12:57, 9 August 2010 (UTC)

From Falkowski et al., Science, 2000:

Region	Gigatons of C (GtC, 1012 kg of carbon)
Atmosphere	720
Oceans	38,400
Total inorganic	37,400
Surface layer	670
Deep layer	36,730
Total organic	1,000
Lithosphere	>75,000,000
Sedimentary carbonates	>60,000,000
Kerogens	15,000,000
Terrestrial biosphere (total)	2,000
Living biomass	600-1,000
Dead biomass	1,200
Aquatic biosphere	1-2
Fossil fuels	4,130
Coal	3,510
Oil	230
Gas	140
Other (peat)	250

Most of the GOE carbon ended up as sedimentary carbonates and kerogens. The amount of carbon that can be burned as fossil fuels is large compared to either the atmosphere or the biosphere, but infinitesimal compared to the amount of carbon that has been incorporated into sedimentary rocks in forms that are not useful for combustion. Burning all of the fossil fuels would be bad, but it would only barely make a dent in the amount of oxygen that exists in the atmosphere. Dragons flight (talk) 07:54, 9 August 2010 (UTC)

That's some really great answers, precisely the kind of information I was looking for. Thanks everyone. Vespine (talk) 03:30, 10 August 2010 (UTC)

Present day radiation levels at Hiroshima and Nagasaki

I was wondering if anyone knew the present day radiation levels above normal at ground level, if any, in Hiroshima and Nagasaki? Thanks. 150.49.180.199 (talk) 05:48, 9 August 2010 (UTC)Mark

I don't have a source for this but I was under the impression that Hiroshima now has the same levels of radiation as the global average. This is because the bomb exploded in the air rather than on the ground, and irradiated air moves on eventually. If it had exploded on the ground, I would expect the perseverance of the radiation to be much worse. Someone feel free to shut me up :) Regards, --—Cyclonenim | Chat  09:47, 9 August 2010 (UTC)

No need to shut you up, you're right. From the little boy article, "Because Little Boy was an air burst 1,900 feet (580 m) above the ground, there was no bomb crater and no local radioactive fallout." The statement has this reference. I would dangerously assume that the conditions were the same for the fat man explosion. Ks0stm ^(T•C•G) 09:50, 9 August 2010 (UTC)

The very first Google search result for 'radiation level hiroshima' [8]. Bing isn't so good (IMHO) finding a bunch of Yahoo answers and other things but does find [9] as the 9th result (6th on Google). Google also finds RERF as the 4th and [10] (see q12) as the 9th result. RERF which I highlighted is perhaps the best of those resources. Nil Einne (talk) 09:59, 9 August 2010 (UTC)

An article "Residual radiation in Hiroshima and Nagasaki"[11] is available for payment from The Lancet. Yahoo Answers says that radiation from the bombs is long gone[12]. Cuddlyable3 (talk) 15:16, 9 August 2010 (UTC)

Is there a reason you continue to cite sources like Yahoo! Answers even though they are clearly not reliable? Do you even read the responses before you cite such things? The Lancet is at least a reliable source but the abstract makes it pretty clear (which I then verified with the actual article) that the article in question is only talking about residual radiation in 1946, not the present day. It is entirely inapplicable to the current discussion. --Mr.98 (talk) 15:52, 9 August 2010 (UTC)

Yeah - Yahoo! Answers is just another "asking random people on the Internet" site - just like this one - except that their reliability has been shown to be vastly worse than ours. We shouldn't reference them because the probability of improving our answer is worse than chance! SteveBaker (talk) 22:40, 9 August 2010 (UTC)

The Marangoni Effect in a wineglass

I recently posted a question concerning the toroidal motion of sediment in the base of a near-empty wineglass (the content was that which had gathered in the bottom over a roughly fifteen minute period). I noted that even though the glass had not been touched for this period and that there were no obvious sources of vibration energy etc. the sediment continued to move in its toroidal pattern seemingly without further input. The Marangoni effect was suggested and I think, having researched this penomenon's various manifestations, that I agree that this is what was going on. My question now concerns the 'actors' in this instance. The Marangoni effect has been presented by various sites as transfer caused an inequilibrium of some sort, be it density, alcohol concentration or whatever, with tantalising hints that surface tension differences point to a more correct interpretation. In my wineglass example, what are the sources of this imbalance? I am assuming that water and ethanol are the major parties and that the sediment simply makes the effect more readily visible, but what is the nature of the inequilibrium and how are the two liquids interacting to resolve it? Also, why does this only happen with a near-empty glass and not a full one (assuming that this observation is true, naturally). I am researching this for a book (fiction) and want to get my facts straight as the explanation is to be given by a (again fictional) professor of fluid dynamics and to an individual who is scientifically literate albeit in a different field.

Thank you in advance.

--Mark David Ward (talk) 08:01, 9 August 2010 (UTC)

Mark's previous question, and the responses, can be seen at Mysterious movement of sediment in a wine glass. Dolphin (t) 08:59, 9 August 2010 (UTC)

I would speculate that the reason this only happens with a near-empty wine glass is because of the amount of energy required to make this start (and continue). The less liquid, the less energy you need. If surface tension or evaporation is implicated, it is also the case that the less liquid there is, the larger the surface-area-to-mass ratio (assuming a roughly hemispherical bottom to the glass). I kinda wonder (without any particular evidence/math to back it up) whether there is some kind of conservation of rotational inertia going on here. Is it possible that a slow motion rotation of the bulk liquid is somehow 'concentrated' into the bottom of the glass as you consume the wine?

We get quite a few questions about the weird behavior of liquids in cups and glasses - they are interesting science - but really tough to answer well! SteveBaker (talk) 22:37, 9 August 2010 (UTC)

The way a slow rotation of the bulk liquid is concentrated into an anomalous activity near the center of the bottom of the glass (and other weird behaviour of liquids in cups and glasses) may be the secondary flow of the boundary layer on the floor of the glass. See Secondary flow#Circular flow in a bowl or cup. Dolphin (t) 05:44, 10 August 2010 (UTC)

Thank you both for your answers, I appreciate the time it takes. One thing I would really like to know though is the nature of the disequilibrium in the wine. Does it concern water and alcohol? If so, what is it about them which makes the disequilibrium appear and how does the motion resolve it? I take the point made about the smaller amount of energy required to move a small amount of liquid making this effect more likely to occur in a near-empty glass, but I wonder if it occurs all the time, near the surface, and is only visible in a near empty glass is that when the glass is near empty, the sediment is naturally involved where it hopefully would not be in a full glass. My theory concerning this effect is that the alcohol water are simply well mixed - the alcohol is not dissolved in the water, or vice-versa, so at the surface there will be a mixture of water molecules and alcohol molecules in contact with the air. The alcohol is less dense than the water and so, given sufficient time will tend to rise, but I suspect that inter-molecular forces will reduce this to a near negligible effect; otherwise alcohol would separate out in stored wine etc. The alcohol is also more volatile and so, will evaporate more readily. I suspect that this is a sufficiently strong effect to cause a gradient in alcohol concentration which drives the motion until the alcohol runs out. Actually, in explaining my thoughts, I realise that I understand this even less well than I thought. Help someone! :)

--Mark David Ward (talk) 18:51, 10 August 2010 (UTC)

Cricket type

I'm looking for a specie of crickets. It is brown with a little orange tail, and can be found here in The Netherlands, I fond alot of them in the dunes. Aeno•talk to me 13:07, 9 August 2010 (UTC)

Chorthippus brunneus

Chorthippus brunneus[13] is called the Common Field Grasshopper in English. "The mature male becomes reddish orange at the tip of the abdomen"[14]. I don't speak Dutch but this page[15] is entitled Bruinesprinkhaan Tandradje (Chorthippus brunneus). Alansplodge (talk) 18:35, 9 August 2010 (UTC)

Thanks! That's the one I was looking for. Aeno•talk to me 15:10, 10 August 2010 (UTC)

pollution

what are the effect of mine blasting on global warming? —Preceding unsigned comment added by Yashodeep1996 (talk • contribs) 14:10, 9 August 2010 (UTC)

Do you mean the use of explosives as part of the mining industry? In that case, there is basically no direct effect. Explosives probably release some greenhouse gases (aiding global warming). Explosions also produce dust (inhibiting global warming). Regardless, the scale is far below the industrial level needed to make a significant impact. One could also discuss the impact of explosives vs combustion-driven equipment vs raw human labor, but I expect that we're still well below meaningful amounts. As a secondary effect, mining can potentially have wide-ranging impacts, but then we've moved away from "blasting" to instead discuss the methods and/or products of mining. Finally, a note on why clarification is important: searching for "mine blasting" on WP predominantly returns results for land mines. — Lomn 15:00, 9 August 2010 (UTC)

According to http://cryptome.info/explosives.htm US explosives production was 2.53 Million tons p.a. in 2004 - assuming that could be the energy equivalent of TNT (TNT equivalent says 1 MT of TNT = 4.183PJ) that's ~10 PetaJoules of energy from explosives. Compare with energy use in the USA for electricity (List of countries by electricity consumption) of 3.9 petawatthours = 14040 PetaJoules - so the fraction is less than 0.1% (of energy from electricity not total energy)

Assuming all that explosion creates 3x as much mass of CO2 then that's ~7.5Million ton of CO2. The USA produced ~6500 million tonnes of CO2 in 2007 List of countries by carbon dioxide emissions so that is clearly about 0.1% of the total emmissions.

It does indeed seem to be a small amount relatively. (Hope my figures are mistake free).87.102.35.46 (talk) 15:43, 9 August 2010 (UTC)

Cement

Is this likely to be portland cement or could it be another type? The article on portland cement suggests that it's the most common type. ----Seans Potato Business 14:13, 9 August 2010 (UTC) I added the missing title. Cuddlyable3 (talk) 14:45, 9 August 2010 (UTC)

If you click on the "Health & Safety Information" box under "Features" on that page, the product heading is "Blue Circle Portland Cements", so I'd say that it's indeed Portland cement. Deor (talk) 14:55, 9 August 2010 (UTC)

More here http://www.lafarge-cement-uk.co.uk/mastercrete.html A "portland composite cement" , there's a pdf on the same page http://www.lafarge.co.uk/CementDatasheet/Mastercrete.pdf there's an improver added which is described in the pdf, it's still a portland cement.87.102.35.46 (talk) 16:28, 9 August 2010 (UTC)

Waking up

Just an up front notice that this isn't a request for medical advice, but general, practical advice.

I seem to have a serious problem waking up to alarms. Alarms, especially when I'm sleeping at home, seem to have a tendency to not wake me up. When I'm sleeping away from home, the effect of me sleeping lighter can occasionally overcome the inability of alarms to wake me up, but normally (and especially at home) I just sleep right through the alarm without even hearing it go off. When/if I hear it go off (wake up), I get out of bed with relative ease, it's just the fact that I don't wake up until after they've been going off for (at times) over an hour. The alarms that seem to do the best at waking me up are my cell phone alarm at full volume and this alarm called the "Screaming Meanie" that produces a noise so loud that it makes my ears ring for hours afterwords (It's never failed, I stopped using this one because I began to think it might be damaging to my hearing). What can I do to increase my ability to get up to alarms considering that I only have one year to acquire the ability before going off to college? In what ways can I maximize my chances of hearing the alarm on any given day? In short, how do you wake up to an alarm when you don't even hear it go off in the first place? Ks0stm ^(T•C•G) 19:12, 9 August 2010 (UTC)

Forgot to add that I do take medication to help me sleep (thus the "I'm not requesting medical advice" disclaimer"), and it does negatively affect my abilities to wake up in the morning. Ks0stm ^(T•C•G) 19:27, 9 August 2010 (UTC)

Go to bed earlier? --Chemicalinterest (talk) 19:32, 9 August 2010 (UTC)

Phone alarms that I've heard tend to be quite...nice. Find a sound that's really really annoying (you may even be able to download such a sound for your phone alarm). 90.195.179.60 (talk) 19:40, 9 August 2010 (UTC)

For example, I find this sound to be unbearable. http://www.youtube.com/watch?v=no4elRUgxmY#t=58s 90.195.179.60 (talk) 19:43, 9 August 2010 (UTC)

If your difficulty waking up is as a result of taking sleeping pills, then its a side-effect of the pills and not something we can help with, since that would be medical advice. You need to talk to whoever prescribed the pills. --Tango (talk) 20:01, 9 August 2010 (UTC)

Option 1: Get a random alarm. Don't increase the volume. Your subconscious listens to the sound and decides if it's important enough to alert you to it. After a while you will get used to an alarm sound, and it will no longer be considered important. But if you give it a new sound it won't know what to do with it. Option 2: You can also train it. During the day play the alarm and as soon as you hear it jump up and be very active - get to the point that it's automatic - you hear the sound, you jump, without even thinking about it. Additional Note: If you are medicated you may be physically unable to wake up, and no alarm will work. Talk to your doctor about the dose. Ariel. (talk) 20:04, 9 August 2010 (UTC)

Sounds like you've got caffeine addiction, or at least you are not getting enough sleep. Give up tea and coffee, go to bed earlier. 92.15.27.40 (talk) 20:20, 9 August 2010 (UTC)

You have a wall of text, so I didn't read it, but have you tried doing nothing more than putting the alarm across the room and seeing if you get up and turn it off then? Secondly, before you go to sleep, reflect on the number of hours you will sleep (count): picture that many hours, then picture yourself getting up afterward. Finally, if you are not going to get at least 6 hours, set the exact time to be an increment of 90 minutes (or 45) from when you will fall asleep (7 to 15 minutes after you set the alarm.). If it's 2:20 AM and I have to get up at 4:15, no way would I be able to do that, I would totally sleep through any alarm. So, I've showever and brushed my teeth, then count 2:20 AM plus 90 minutes is 3:50, and until 415 that's exactly 25 minutes or smack-dab in the middle of a cycle. I will set it for 3:50 instead, reflect on the 90 minutes of sleep I'm about to get, and fall asleep. I get up on time, and won't be particlularly tired until 4-6pm the next day, when the hour and a half of sleep will cath up with me. My point is, if instead of an hour and a half it had been an hour and fifty-fie minutes, no way would I have been able to get up.

of course, the best policy is to go to sleep on time: no caffeine after 6 pm!! 85.181.49.221 (talk) 21:01, 9 August 2010 (UTC)

Ironically, you were unable to read the OP's "wall of text" (253 words), and yet you responded with your own "wall of text" (256 words), which was even more pointless given that you had not bothered to read the question. If that's the best you can do, you're better off not answering. --Mr.98 (talk) 01:16, 10 August 2010 (UTC)

It's not that long a question and had you read if you would have learned that the OP has no difficulty getting up once awake, the problem is waking up. --Tango (talk) 22:25, 9 August 2010 (UTC)

I found that waking up to a talk-radio station - or using a talking alarm clock ("The time is six forty-five A.M."...updating every 5 minutes) - works much better than music or beeps/bells/squawks, etc. Evidently the sound of voices does the trick for me. I don't think volume is the answer.

SteveBaker (talk) 22:29, 9 August 2010 (UTC)

I'm with Steve. Try something other than an alarm noise. I found that when my clock made loud alarms, I would instinctively mash the snooze button and go back to bed without even remembering doing so. I only realized it had happened when I eventually woke up (much) later than intended. After switching it to play music instead, sometimes a really good song will happen to be on the radio and I'll stay awake a few minutes to listen to it. By the end, I'm about ready to get up. Worth a shot. 75.157.57.12 (talk) 08:38, 10 August 2010 (UTC)

If the sound of an alarm doesn't wake you, how about buying a vibrating alarm clock? There appear to be a lot on the market, aimed at those who are deaf or hard of hearing. Smartse (talk) 22:40, 9 August 2010 (UTC)

There are various ingenious alarm clocks which will start Rube Goldberg devices to pull off the covers, vibrate the bed, dump you out of bed on the floor, make louder and louder noises, etc. My deaf niece has an alarm which shakes the bed, so such things are readily available. A silent movie by Thomas Edison from the early years of the 20th century had a man who couldn't wake up tie a rope to his ankle and leave it dangling out side the window, for his friend to tug on it in the morning and wake him up. Naturally hilarity ensued with a drunk yanking on it, etc, and eventually a wagon getting tied to it , with the horse setting off and dragging the sleeper out the window and through the town. Therefore I do not recommend the ankle rope through the window routine. "Inability to wake up" sounds like a medical issue, although I have known young adults in whom it seemed to be a form of rejection of responsibility and passive aggression where sleep medication was not involved. "Alarms don't wake me up" might be a form of rejection of responsibility, like "It's Mommy's job to get me to high school on time." No, it's your job, no one else's. If the alarm clock gets louder and louder, eventually it will annoy the dorm neighbors, who will pick the room lock and dump icewater on the sleeper or shoot him with pepper spray until he learns to get up and be a productive member of society. Or he will flunk out of school due to missed exams, or get fired from his job. Edison (talk) 01:47, 10 August 2010 (UTC)

Oddly, I find visualisation really helps me wake up at the right time. While lying in bed before going to sleep, I picture the current time, and picture the time I need to wake up, and think about those and the time difference between them. I think to myself that I must get up at that time, or I won't have time to get ready and leave the house. I picture myself getting up quickly and immediately at that time, and do a quick imaginary run-through of the first few minutes of my morning routine. I've had real problems waking up to alarms for a while, but when I do this I manage much better. The only problem is that it can lead to anxiety, if not done carefully, which then makes it harder to get to sleep in the first place! 82.24.248.137 (talk) 22:01, 10 August 2010 (UTC)

Q: Today's featured pic

File:Seven Sisters Panorama, East Sussex, England - May 2009.jpg.

What's in the yellow mounds on the green (top right) ? East of Borschov 21:04, 9 August 2010 (UTC)

It's hard to tell at this distance, but it may be gorse or heather, flowering yellow. -- Finlay McWalter • Talk 21:12, 9 August 2010 (UTC)

My guess would be gorse - while it's hard to get the scale on a picture like that the plants look rather too tall for most heathers. But yes, it could certainly be either. ~ mazca ^talk 21:55, 9 August 2010 (UTC)

There are lots of types of common yellow flowers in that part of England - it could be buttercups or any of half a dozen other things. What's odd about the picture is that the yellow patches are only visible on top of clumps of dirt - not on the flat grassy bits. I suppose the exposed dirt might get re-inhabited by flowers before the grass can take over and choke it out or something. It's hard to tell without a closer inspection. SteveBaker (talk) 22:24, 9 August 2010 (UTC)

Steve, if you go to full resolution (the picture is huge) it's very obvious that the plants are flowering low bushes, not small ground flowers on 'clumps of dirt.' 87.82.229.195 (talk) 10:01, 10 August 2010 (UTC)

The harsh environment of a hilltop precludes most meadow and forest wildflowers, and the proximity to the sea make it worse. You do find flowering plants in a seaside Machair environment, but this is the wrong location, altitude, and geology. That leaves very hardy low-lying shrubs - if it's not heather or gorse, it's something of a similarly tough, and mostly inedible, disposition. The "clumps of dirt" are just the non-flowering bits of the shrub. -- Finlay McWalter • Talk 22:36, 9 August 2010 (UTC)

I'm certain it's gorse; *When gorse is out of blossom, kissing's out of fashion"[16] (old English saying). Alansplodge (talk) 02:30, 10 August 2010 (UTC)

I agree, it is almost certainly gorse on the grounds that I cannot identify an alternative. Yellow heather is possible but very unlikely given the alkali nature of the soil. It might be dwarf gorse, but again it is out of its normal habitat. Richard Avery (talk) 07:52, 10 August 2010 (UTC)

Crayfish in New Jersey streams

What crayfish is this?

What is this crayfish? It has a dark brown shell and is rather large. I found it in a local stream in New Jersey. --Chemicalinterest (talk) 22:25, 9 August 2010 (UTC)

Only a guess but Signal crayfish seems to fit. The one in the picture I wouldn't describe as "rather large" however. If not that it could be one of the other Pacifastacus but there isn't really enough info on most of the others to make a guess.. Vespine (talk) 03:42, 10 August 2010 (UTC)

It is the less common crayfish. The more common ones are lighter brown 2 cm (1 inch) long crayfishes. They are found in all other streams. These range from 2 cm to about 8 cm. --Chemicalinterest (talk) 11:01, 10 August 2010 (UTC)

Rusty crayfish? Not enough description though. --Chemicalinterest (talk) 13:51, 10 August 2010 (UTC)

Having a look at google images, maybe I was a bit too ambitious thinking I could have a reasonable guess, lol.. The subject looks a lot more complicated then I initially thought, looks like I even got the family wrong! I'd say your guess looks better then mine. Vespine (talk) 23:01, 10 August 2010 (UTC)

Looking for reference for an experiment about expectations and performance

I remember seeing on TV something about an experiment relating expectations and academic performance. In the experiment, students were divided into two groups and given identical math problems. One group was told that the problems were difficult. The other group was told something different, I think something to the effect that they should try hard, or something similar. In the end, the group that expected the problems to be difficult (and beyond the students' abilities?) did worse than the other group. I'm writing this from memory so I might have got some of the details wrong. Does anyone know what experiment that was? --71.185.169.212 (talk) 23:12, 9 August 2010 (UTC)

This sounds similar to the Pygmalion effect, and it reminded me of a story about George Dantzig. Ariel. (talk) 06:15, 10 August 2010 (UTC)

Three meals a day?

I've been thinking: A lot of people who are obese start out overeating by eating past satiation thinking they need to "stave off" hunger until the next meal, and misjudge how much they need. If people always only ate just enough to feel satisfied and did this again everytime they felt hungry rather than eating the standard 3 meals a day, would they keep gaining weight? And how much would this differ based on the quality of the diet? 68.76.158.13 (talk) 23:14, 9 August 2010 (UTC)

There are those that claim people should eat small meals regularly throughout the day. They claim this raises the basal metabolic rate and regulates insulin levels. This article discusses one such diet, and its critics - it seems there isn't enough evidence to know for sure. Similar advice (with similarly scientific sounding reasons) is often given to bodybuilders (e.g. bodybuilding.com, wikihow). All of these are more to do with claims about metabolism and insulin levels, and not so much about your "eat when you're hungry" theory (although hunger and insulin are related). -- Finlay McWalter • Talk 00:13, 10 August 2010 (UTC)

For many fat people, hunger is more psychological than physiological. If they see someone eat something good, they suddenly become unbearably hungry regardless of stomach fullness or blood sugar. If they smell fresh baked doughnuts, they are suddenly hungry. Hunger may attack 30 minutes after a big meal if something tasty is seen. Edison (talk) 01:33, 10 August 2010 (UTC)

For some people the "I'm hungry" meter is set wrong, and causes them to desire more calories than they need. So even if they obey hunger perfectly they may still become fat (i.e. they need 100, they want 110, so over time they get fatter and fatter). In other people the "perfect weight" setpoint is simply set high. So if they go lower then get extra hungry, but if they reach it then calories desired matches calories needed and they simply stay at that weight. So to answer your question: No. That would not solve the problem in many people. (But it would in some.) Ariel. (talk) 06:06, 10 August 2010 (UTC)

There is also the issue of people responding to "I'm thirsty" by eating instead of drinking water. That is the reason that liquid diets tend to be slightly successful in some people. It suppresses the "I'm thirsty" trigger. It does absolutely nothing for people who overeat for other reasons. -- kainaw™ 06:16, 10 August 2010 (UTC)

To go back to the original post one cannot disagree with the idea that if most people ate less they would be thinner. This is similar to the idea that if everyone drove a little slower there would be less accidents and deaths on the roads. The development of obesity is multifaceted and varies with individuals. The basic problem is overeating, but the causes of overeating are more complex than just feeling hungry at the sight of attractive comestibles. We have to consider self esteem, the inability of the individual to notice changes in body shape, the denial of a person to accept their obesity, the social acceptability of obesity, the insistent advertising by commerce, the increased availability of food, the increasing use of inappropriate ingredients in foodstuffs . . . and so on. Obesity is here to stay, and probably will worsen in the future.steps off soap-box. Richard Avery (talk) 07:34, 10 August 2010 (UTC)

Completely disagree. People eat too much for different reasons, and lack of access to healthy and nutritious food, large portions, lack of exercise, and a sedentary lifestyle supported by automobile transportation, television habits, gaming and internet, and desk-related work are all big contributors to obesity. Once you address all of these factors, you are well on the way to controlling your weight. Losing weight requires changing your entire lifestyle, and most people will not take that first step. Viriditas (talk) 03:37, 11 August 2010 (UTC)

Modern food has many calories in relation to its bulk from fat and processed carbohydrates (eg bread, pasta). It has also been designed to be very tasty and nice to eat. Bulk weight and fibre satiates hunger, not calories. Thus we overeat. I think eating a lot of vegetables and fruit while avoiding processed foods is the way to avoid weight gain without hunger. But evolution did not design us to cope with food always being available. See http://nutritiondata.self.com/topics/fullness-factor 92.29.121.47 (talk) 10:40, 10 August 2010 (UTC)

How are bread and pasta "modern"? Bread has been around for millennia and pasta for at least a few centuries (its exact origins are disputed, it could easily be a couple of millennia old as well). Also, wouldn't something that satiates hunger without providing calories tend to make us undereat, not overeat? --Tango (talk) 11:04, 10 August 2010 (UTC)

You may be surprised, but bread and pasta are certainly not archaic foods and are currently available in many shops thoughout the world. I think I saw them for sale as recently as yesterday. Indeed, I consumed some myself a few days ago. I don't understand your comment about undereating, not something that most people (at least in the West if you want to pick pedantic hairs) will be in any danger from. 92.15.3.61 (talk) 16:06, 10 August 2010 (UTC)

Well, historically, the Early modern period began in Europe more then 500 years ago... Googlemeister (talk) 13:23, 10 August 2010 (UTC)

Skipping breakfast will simply make you more fat. ~AH1^(TCU) 23:52, 10 August 2010 (UTC)

Very interesting thread, the original poster is right, there are several study trials which have been conducted and have unanimously opined that smaller frequent meals DO INDEED reduce obesity. A quick search of national library of medicine ( www.nlm.nih.gov) will give you details of several trials which have come to the same conlusion. Smaller quantity, frequent meals definitely trigger insulin release and help in carbohydrate breakdown, it helps prevent distention of abdomen and also helps increase the basal metabolic rate. So the original poster is spot on and as a medical practitioner I have to agree with him/her. However, the subsequent posters have also presented valid facts, fighting obesity isnt a unidimensional battle. You just cant control diet alone and hope to win the battle against the bulge. Lifestyle modifications, fitness exercises and mental discipline are very important factors too. --Fragrantforever 07:16, 11 August 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)

August 10

What's the prospect of scientists creating enzymes that can treat prion diseases?

Based on what we know about prion diseases, what's the prospect that someday scientists will discover or engineer enzymes that can be used to safely break down amyloid plaques? --71.185.169.212 (talk) 01:50, 10 August 2010 (UTC)

I can't see any reason why it couldn't be done. They're just proteins and there are plenty of enzymes that break down proteins. I don't know enough about the subject to say how difficult it would, though. If scientists can find people with a genetic immunity that works by them producing a particular enzyme, then they might be able to track down the relevant gene, transplant it into a bacteria and then extract large amounts of the enzyme and administer it to patients, but no part of that process would be particularly easy. --Tango (talk) 03:10, 10 August 2010 (UTC)

Amyloid plaques consist of fragments of a larger protein, that build up outside of neurons. The key problems are those of drug delivery, as getting large molecules into the brain is extremely difficult, and selectivity: how to find a protein that digests amyloid plaques while leaving healthy proteins unaffected. I don't know for sure, but the amyloid plaques may be as much a symptom as a cause of the disease -- the breakdown of their parent protein may be the actual cause. Alzheimer's is also characterized by aggregation of an intracellular protein involved in maintaining the neuronal cytoskeleton, which would be even harder to target as it's intracellular. --Atemperman (talk) 05:25, 10 August 2010 (UTC)

Some care should be taken here with nomenclature. The prion protein PrP forms the amyloid plaques that appear in the transmissible spongiform encephalopathies ('mad cow disease' in cattle, or Creutzfeldt-Jakob disease in humans) — but not all amyloid plaques are formed from prions. Indeed, when neurologists discuss amyloid plaques, the first thing that comes to mind is usually the amyloid beta peptide associated with Alzheimer's disease. (It is in this sense of the term that Atemperman's response above answers the question.) Amyloid beta does form amyloid plaques, but it is not believed to be a prion — amyloid just describes protein accumulations with a cross-beta structure and which exhibit certain histopathological features (like apple-green birefringence when stained with Congo red). It's also worth bearing in mind that PrP is not the only prion protein (several others have been identified in yeast, though PrP is so far the only known mammalian protein which can form a prion).

I'm going to assume that you're interested in the breakdown of PrP amyloid for the remainder of my response here. Developing a suitable protease requires meeting three major challenges. The first is that the protease even be able to digest PrP amyloid. This is a steep challenge all by itself; one of the hallmarks of PrP amyloid (and indeed, of most amyloids) is their resistance to protease digestion. PrP amyloid is resistant to detergent solubilization and even to exposure to proteinase K, which is able to digest normally-very-durable proteins like keratin (in hair). Nevertheless, there has been some work in this area; this paper describes some very aggressive enzymes secreted by thermophilic bacteria that might be able to do the job. (I'm not familiar with the literature in this area; that was just one of the first Google hits with the relevant keywords.)

The second challenge is one of specificity. Letting large amounts of an aggressive protease loose in human tissue is a recipe for disaster, unless it can be specifically targeted to PrP (ideally, just to misfolded PrP). The third challenge is delivery — Atemperman's response above describes the problem. TenOfAllTrades(talk) 18:51, 10 August 2010 (UTC)

Why did they change the iphone's antenna?

I don't recall any problems with the old one. What was the purpose of the change? 148.168.127.10 (talk) 13:24, 10 August 2010 (UTC)

They probably keep mum about this. But essentially, they wanted a new design (and may have needed more space or a different layout to realize the enhanced functionality). And from a technical point of view, reusing the structural elements of the frame as an antenna is exactly one of those very elegant ideas you fall in love with that unexpectedly turn around and bite you... --Stephan Schulz (talk) 13:37, 10 August 2010 (UTC)

Apple claims, and several independent tests have supported, [17] that the change improves reception in low-coverage areas -- provided that you don't hold the phone a certain way. My personal guess is that Apple's internal testing just didn't uncover the flaw: they've got an AT&T tower on their campus, so local testing isn't bothered. The phone that leaked in the field was enclosed in a case (which fixes the problem) -- so if that's typical, remote testing also wouldn't be bothered by the antenna placement issue. But that part is just guesswork. — Lomn 13:41, 10 August 2010 (UTC)

Ironically, the new antenna was designed to improve the connection. My own personal experience has been that the iPhone 4 is indeed better than previous models as long as you don't hold it with the Death Grip. A Quest For Knowledge (talk) 13:47, 10 August 2010 (UTC)

In addition to the suggestions above, relocating the antenna to the outside of the case frees up room inside. This allows more internal space for additional hardware or a larger battery.--Zerozal (talk) 14:08, 10 August 2010 (UTC)

watch what they do after September 30th. I bet by then they'll have sold all the ones produced with revision 1, and be selling the revision 2: what is that change? Perhaps nothing more than a resinous coating... 92.230.233.247 (talk) 14:45, 10 August 2010 (UTC)

is this text to speech or just a nerdy guy?

http://grail.cs.washington.edu/projects/videoenhancement/ I can't tell... —Preceding unsigned comment added by 92.230.233.247 (talk) 13:55, 10 August 2010 (UTC)

Sounds like a person to me, and his voice seems totally normal to me. Ariel. (talk) 16:50, 10 August 2010 (UTC)

Agreed. He enunciates a little funny, and doesn't modulate much, but it's probably because he's trying to be easy to understand (he's not speaking conversationally). He's no voice actor but he does fine by academic standards. --Mr.98 (talk) 00:03, 11 August 2010 (UTC)

Cool research. Definitely a real person. A text-to-speech program wouldn't have gotten the rhythm of spoken language correct. For a particularly striking example, consider the phrase around 4:47: "The resulting mat # is consistent with the occlusions in the scene." The speaker puts a big pause at the "#" to let the listener focus in preparation for the coming big concept. There's no punctuation there; it takes intelligence to decide to put it in. Paul (Stansifer) 03:55, 11 August 2010 (UTC)

I think the speaker is using speed-up voice processing to limit the length of the video. Cuddlyable3 (talk) 10:13, 11 August 2010 (UTC)

yes! that must be it. thank you. the actual audio does sound computationally produced (as opposed to spoken as we hear it), because it is, but is a real person, because it is. 92.230.232.58 (talk) 11:29, 11 August 2010 (UTC)

Eh, I don't buy it. Sounds like a regular voice to me. Perhaps not one that you yourself hear around often, but around universities and science departments, it is not uncommon. --Mr.98 (talk) 13:02, 11 August 2010 (UTC)

Frogs!

Is this a leopard frog or a pickerel frog? --Chemicalinterest (talk) 13:58, 10 August 2010 (UTC)

Frog in question

The striping would lead me to think it is a leopard frog as I don't think pickerel frogs have such stripes. Googlemeister (talk) 14:13, 10 August 2010 (UTC)

This picture of a pickerel frog (from Frogs in New Jersey) is what started my question. --Chemicalinterest (talk) 14:34, 10 August 2010 (UTC)

According to the pickerel frog article, a pickerel frog is a type of leopard frog. (It doesn't say so explicitly, but it has a sentence that reads "All other leopard frogs ...".) Looie496 (talk) 22:43, 10 August 2010 (UTC)

Cycle helmets - do they reduce vision and impair hearing?

Hi all, thanks for reading.

A the title asks really, do cycle helmets impair peripheral vision and hearing, leading to greater likelihood of being involved in an accident?

I've been ot the CTC site ( http://www.ctc.org.uk/ ), and looked up some reports on helmet safety through google scholar, but they all seem to focus on injury patterns for helmet wearers and non wearers involved in accidents. I'm trying to find out if wearing a helmet actually does increase the likelihood of being involved in an accident.

Some facts/figures/reports would be great to back this up if you guys could.

This isn't homework, I'm having a robust conversation with a number of people on some forums, and its something I've been curious about for a while, but could never find the research to back-up my assertion that helmets do impair sensory perception, and in doing so, increase the likelihood of being involved in an accident.

Cheers all, Darigan (talk) 14:01, 10 August 2010 (UTC)

These guys seem to manage OK. They're just the best in the world.

The peloton of the Tour de France

Sorry, I know that's not an answer, but yours does seem to be a question based on rebellion and an unwillingness to change. HiLo48 (talk) 14:25, 10 August 2010 (UTC)

Look at this helmeted fellow. He would have to strain to see the helmet, and it's hard to believe it has any significant effect on his hearing. This is a bit like arguing that seatbelts are bad because they might trap you in a burning car. Perhaps true in a tiny minority of cases, but statistically marginal compared to the times they prevent serious injury. --Sean 14:28, 10 August 2010 (UTC)

I bicycle a lot. Helmets are uncomfortable when it is 38C (100F) outside, but they do not seem to impair my hearing because they do not normally cover the ears. Normally they do not cover any of the sight range either (at least for my Schwinn helmet). --Chemicalinterest (talk) 14:32, 10 August 2010 (UTC)

There would be many factors to control for in any study. For example, maybe cyclist who where helmets are simply more careful (in general) than cyclists that don't, and so would be expected to have a lower rate of accidents. You would want to start by asking yourself how many cycle accidents are caused by ignorance of peripheral vision or hearing on the part of the cyclist (whether wearing a helmet or not). As a personal opinion, I don't buy the peripheral vision argument: a cyclist should always look over the shoulder to avoid the blind spot, and the blind spot is not affected in the slightest by wearing a helmet or not (it's way to the front of any helmet design). Physchim62 (talk) 14:42, 10 August 2010 (UTC)

Cheers all

@HiLo48 - You may have a point, and LOL at the Tour pic.

@Physchim62 - That was the main issue with the studies I did come across - the variables, particularly the ones that you mention, as well as issues of variable cycling competency, and the localities covered in various studies (obviously, road conditions, but also, localities with higher number of cyclists might record lower a lower than expected ratio of accidents because motorists the frequent that area are more familiar with sharing the road with cyclists etc).

I accept that my boldly proclaimed opinions on the subject elsewhere may have been entirely factually incorrect. Darn.

Thanks all, Darigan (talk) 15:01, 10 August 2010 (UTC)

On the hearing front, I'd suggest that cyclists have more to be concerned about with the increasing numbers of virtually silent electric cars, than with helmets. HiLo48 (talk) 21:37, 10 August 2010 (UTC)

HEY LOOK WE HAVE AN ARTICLE Bicycle helmet WHICH COVERS MUCH OF THIS. Although it doesn't seem to mention the way that drivers will assume you are more experienced if you wear a helmet, despite that being almost exactly the opposite of the pattern, and hence will give you less space and you'll have more serious accidents. 82.24.248.137 (talk) 21:47, 10 August 2010 (UTC)

I would caution readers that the source linked above (a BBC story) doesn't quite jump to the same conclusions that the poster does in his text. The story only describes a study which noted that vehicles tend to pass closer (8.5 cm or about 3.3 inches; roughly 10% less total space) to cyclists wearing helmets than they do to cyclists without. The authors of the study speculate that drivers may assume a greater level of cycling competence, experience, and/or predictability on the part of the helmeted cyclists, and therefore those drivers may pass the cyclists more closely. The article does not indicate that helmeted cyclists are at greater overall risk, nor does it describe any research into this effect.

Incidentally, our article on bicycle helmets seems to be written in a very non-standard essay-like format, and probably should be reviewed. TenOfAllTrades(talk) 22:15, 10 August 2010 (UTC)

I just tried on my helmet, which I think is a pretty ordinary one, and noted that I can't see any part of it whatsoever while I am wearing it, even with my peripheral vision. Nor does it cover my ears. Looie496 (talk) 22:48, 10 August 2010 (UTC)

Some helmets come with sun visors, which normally can be snapped off. I think it's a good idea to snap them off — they do make it a bit hard to see forward when you're bent over for a descent, unless you hold your head in a tiring and unnatural position. The downside is that you lose the sun protection, but there's sunscreen and UV-protecting glasses for that. --Trovatore (talk) 22:51, 10 August 2010 (UTC)

paint stirrers

what are those free paint stirrers made from? are they real wood? —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 14:06, 10 August 2010 (UTC)

No, they are just leftovers from cutting real wood. 92.230.233.247 (talk) 14:07, 10 August 2010 (UTC)

Aren't "leftovers from cuttings [of] real wood" real wood? Regards, --—Cyclonenim | Chat  17:06, 10 August 2010 (UTC)

No the real wood has been sold as boards, two by fours, what have you. Like sawdust, these stirrers are just what falls to the ground during the cutting. 92.230.233.247 (talk) 17:59, 10 August 2010 (UTC)

I get where you're coming from, but those cuttings come from the original 'real' wood. So aren't the stirrers, by composition, exactly the same? Perhaps with a few impurities. Maybe I'm just not understanding you properly, I'm pretty slow today. Regards, --—Cyclonenim | Chat  18:08, 10 August 2010 (UTC)

But then by using that logic, particle board (basically a sawdust-glue mixture pressed flat) could be called real wood. Googlemeister (talk) 18:43, 10 August 2010 (UTC)

I actually have to agree with Cyclonenim here. If the stirrers are made from a solid piece of scrap wood, they're still 'real' wood by any meaningful usage of the term. Particle board isn't comparable because that's a composite of particles of wood (sometimes not even that but other fibre) held together by a binder. In a similar way, someone may say a meat patty of some sort (burger, meatball, nugget etc) isn't 'real' meat but small pieces of meat which may be scrap and used for a stir fry or whatever is still 'real' meat. Note we have an article on Engineered wood, I'm pretty sure scrap wood of the form described by 92 doesn't fit in to it. In fact, very often people may use scrap wood from a building site or whatever to make things, no one is going to say that isn't 'real' wood. Nil Einne (talk) 19:14, 10 August 2010 (UTC)

I call on 92.230's claim that paint stirrers are scrap wood. Looking at sites like this, it's clear that they're sawed and shaped in bulk, which does not scream "scrap wood" to me. Comet Tuttle (talk) 18:44, 10 August 2010 (UTC)

Have to agree with CT here. See also [18] [19] [20] these Chinese sellers. Don't exactly scream 'scrap wood' to me either Nil Einne (talk) 19:30, 10 August 2010 (UTC)

Transforming a principal stress tensor to maximum shear stress tensor?

The author re-posted the question to the Mathematics Reference Desk, which was the more appropriate Desk. See HERE. Dolphin (t) 22:50, 10 August 2010 (UTC)

Chemistry/Software question

This is kinda science related and also software-related, but I reckon the people who are best to answer it are at this desk rather than the computing one. Are there any open source/freeware programs that do the same job as the FULL ChemSketch? Personally I can't afford to buy the program and I don't want to resort to illegality in getting it. Regards, --—Cyclonenim | Chat  17:09, 10 August 2010 (UTC)

List of software for molecular mechanics modeling has a list; you might want to make a list of specific features you need (many on that list are computational molecular dynamics tools, with "sketching" or 3D image rendering as just a side-benefit). The article molecule editor has a less-well-organized list, but may be more what you're looking for. List of molecular graphics systems, too. I think we might need to consolidate (or just organize) these articles. Nimur (talk) 18:24, 10 August 2010 (UTC)

What is a tensor?

I read the article on it, but I'm still not sure what it even is. In layman's terms? 148.168.127.10 (talk) 18:32, 10 August 2010 (UTC)

I struggled with these at university and only got them the third time round. If you understand vectors, then that's a start as they are 1st order tensors (I'm going back a few decades here so others will I'm sure correct me if I'm wrong). Some physical things such as stress and strain need 9 'components' to fully describe them and for elasticity, which relates stress to strain, you need 81 components and that's a 4th order tensor. As the tensor article says, the stress tensor (2nd order) describes the relationship between two vectors (1st order tensors). I doubt that helps, as it's very difficult to describe this in laymen's terms, but good luck anyway. Mikenorton (talk)

Not the OPHow would that make them not vectors? Can't vectors have an arbitrary number of components? 82.24.248.137 (talk) 21:35, 10 August 2010 (UTC)

Well, they are vectors in some sufficiently abstract sense. But that doesn't really say much — it just says you can add them and multiply them by scalars, and the normal obvious things happen.

The general question "what is a tensor?" is probably not going to have a really satisfying answer right now. You could say that it's a linear transformation from some power of a vector space to some power of a vector space, but I don't think that really gives the sort of intuition you're asking about.

Instead, I'd recommend studying some particular simple tensors, preferably of rank 2. The stress tensor is a good one — think of it as a rule that takes a little flat piece inside the object (which you can think of as a vector, with magnitude equal to the area of the piece and direction perpendicular to the piece), and returns a vector representing the force through that piece. Figure out why that's a linear transformation (hardly obvious!) and you've got a start.

Another one to examine is the moment of inertia, which takes a vector representing the object's angular velocity and returns one giving its angular momentum. --Trovatore (talk) 21:42, 10 August 2010 (UTC)

A tensor, in the simplest possible terms, is a multidimensional matrix attached to a point in a multidimensional space, with the numerical entries in the matrix changing in specified ways when the coordinate system for the multidimensional space is altered. Looie496 (talk) 22:33, 10 August 2010 (UTC)

Those might be the simplest terms in some sense, but they're not the most illuminating ones. Better to emphasize coordinate-free formulations. --Trovatore (talk) 22:38, 10 August 2010 (UTC)

The tensors that show up in physics are usually either symmetric or antisymmetric. I don't know if "layman's terms" includes calculus, but both of these special classes of tensors are probably best thought of in calculus terms.

A symmetric rank-n tensor is what you get when you generalize nth derivatives to functions of more than one variable. The first derivative of a real-valued function of real variables is a vector (rank-1 tensor), called the gradient, whose components are (∂f/∂x, ∂f/∂y, ...). The second derivative is a matrix (rank-2 tensor) called the Hessian. It's a symmetric matrix because the order in which you take partial derivatives doesn't matter. In the case of a function of one variable, you get a one-component vector and a 1×1 matrix whose sole component is the usual first or second derivative. The most useful thing to know about symmetric real matrices is the spectral theorem, which says that you can always make the matrix diagonal by some orthonormal change of basis variables. Thus you can think of a symmetric rank-2 tensor as a set of perpendicular coordinate axes (the diagonalizing basis) with a number (the corresponding element on the diagonal) attached to each axis. These axes are sometimes called "principal axes". In terms of the original scalar function, what this means is that every smooth surface can be approximated locally to second order by an ellipsoid (just as it can be approximated locally to first order by a plane).

An antisymmetric rank-n tensor is a differential form, which is the thing that you write after an n-dimensional integral sign. For example, f(x,y) dx dy is a differential 2-form. In matrix form it would look like ${\biggl (}{\begin{smallmatrix}0&f(x,y)&0\\-f(x,y)&0&0\\0&0&0\end{smallmatrix}}{\biggr )}$, assuming three dimensions with x and y the first two. It's antisymmetric because dx dy represents a little parallelogram in space (the "area element"); if you swap dx and dy the area element flips over, changing its sign, and if you make dx and dy the same vector it collapses to zero size. dx dy is more properly written $dx\wedge dy$, where $\wedge$ is the wedge product, which is this case is the same as the 3D cross product. The number of independent components of an antisymmetric tensor is given by entries of Pascal's triangle. In three dimensions antisymmetric tensors of rank 0, 1, 2, 3 have 1, 3, 3, 1 components respectively, and they are scalars, vectors, pseudovectors, and pseudoscalars respectively. In four dimensions the tensors of ranks 0...4 have 1, 4, 6, 4, 1 components. The first two are scalar and vector and the last two are pseudovector and pseudoscalar. The middle one, in 3+1 spacetime dimensions, can be decomposed into a 3D vector and a 3D pseudovector. This is how the electromagnetic field tensor decomposes into electric and magnetic field vectors. There's more that could be said about antisymmetric tensors, but I'll leave it at that. -- BenRG (talk) 06:00, 11 August 2010 (UTC)

<- This very nice Introduction to Tensors for Students of Physics and Engineering from NASA might help. Sean.hoyland - talk 09:03, 11 August 2010 (UTC)

satellites.

Have we (humans) placed any satellites that are in retrograde orbit around anything besides earth? Googlemeister (talk) 19:04, 10 August 2010 (UTC)

• Our article Artificial satellites in retrograde orbit suggests that the answer is probably no, but it's a rather poor article. --M@rēino 19:16, 10 August 2010 (UTC)

Yeah I looked at that article and thought the same thing, especially since it would require a massive energy expenditure around any extraterrestrial body I can think of except perhaps Venus. Googlemeister (talk) 19:18, 10 August 2010 (UTC)

No, I don't think so. For Earth, where you get the rotation speed for free (or have to compensate for it), the difference is major. But for any other body, the rotation of the body is irrelevant - you're dropping in from outside the system, anyways, and, as long as the rotation is not relativistic, the other body simply behaves as a point mass. You can essentially chose any orbit you like. I would suspect that probes often chose a polar orbit, since that allows them to map the whole body over time. --Stephan Schulz (talk) 21:25, 10 August 2010 (UTC)

Plus, craft that we put in orbit about other bodies are either doing scientific/photographic missions or dropping off landers - and the lower the relative speed between surface and orbiter, the sharper the photos can be and the lower the re-entry speed of any lander. Using a retrograde orbit would pretty much guarantee worse results. SteveBaker (talk) 02:48, 11 August 2010 (UTC)

Most intelligent bird

Can you tell me which bird species is generally considered to be the most intelligent in the world? --95.148.105.77 (talk) 21:01, 10 August 2010 (UTC)

Corvidae are generally considered the most intelligent bird species family, for the reasons (and sourced ones at that) presenting in the introduction to the article. You may also enjoy reading bird intelligence. Regards, --—Cyclonenim | Chat  21:09, 10 August 2010 (UTC)

Corrected, it's a family of birds rather than an exact species. It'd be hard to pinpoint between the species within the family for they are specialised at different things. Regards, --—Cyclonenim | Chat  21:11, 10 August 2010 (UTC)

Grey Parrots are recognized for their cognitive language skills, though ravens are very good at solving problems and can count to 6 or 7. Googlemeister (talk) 21:25, 10 August 2010 (UTC)

I would like our questioner to tell us what he or she thinks intelligence means, especially in birds. We have enough trouble agreeing on what it means for humans. When we try to apply the concept to totally different creatures it becomes very difficult to agree on what it means. HiLo48 (talk) 21:32, 10 August 2010 (UTC)

The smartest corvid would make for a dumb human. But at the same time, the smartest human would make for a dumb corvid. HiLo48 is right. Perhaps all you can say is that, amongst the various kinds of birds, the corvid's intelligence is most similar to human intelligence.91.104.151.200 (talk) 00:12, 11 August 2010 (UTC)

August 11

Dunning–Kruger effect

Our article on this effect includes a short bit of discussion about individuals who previously recognised this effect. Would it be reasonable to say that Socrates observed this effect, since according to legend he was told that he was the wisest of all men because he knew that he wasn't wise? Nyttend (talk) 02:13, 11 August 2010 (UTC)

I don't think we could say that with confidence about someone who lived 2500 years ago. SteveBaker (talk) 02:44, 11 August 2010 (UTC)

Why not? I don't see the difference, especially since the article includes those who remarked about the phenomenon before Dunning or Kruger were born. Nyttend (talk) 04:57, 11 August 2010 (UTC)

"according to legend" - nuff said. Note that if you are trying to add it to the article, you should be discussing it in the article talk page not here. Presuming other sources have made the connection you may be able mention that, it doesn't mean we can say with confidence Socrates observed the effect which is a quite different thing.

I would also note your statement doesn't really support the claim at all since you say "he was told that he was the wisest of all men because he knew that he wasn't wise" which would suggest someone else recognised this effect not Socrates. Whether Socrates even recognised the effect once told about it or whether he thought the person who said he was the wisest of all men because he knew that he wasn't wise was an idiot is not even clear from what you've described.

Nil Einne (talk) 06:32, 11 August 2010 (UTC)

Banding during sunset

Take a look at this picture I took of a sunset.

What's up with the bands of colors?

Notice the banding? Does anyone have any idea what might be causing that banding? It's not just a photographic artifact (though it may be not faithfully recreated by the camera); I took the picture because I noticed the banding with my eyes. At the bottom is obviously a cloud in front of the sun, but on the other half of the sun, there's nothing obvious to cause the interesting coloring. It was taken August 5th in southern Minnesota, if that makes a difference. Buddy431 (talk) 02:38, 11 August 2010 (UTC)

Mach bands - maybe. SteveBaker (talk) 02:42, 11 August 2010 (UTC)

My guess is that the photograph was taken on a day when there were numerous layers of diffuse cloud and strata of humidity, perhaps enhanced by strata of pollutants. The photograph was taken when the sun was in such a position that it was observed through a number of these strata. As a result, the color of the sun was affected by the various strata in the atmosphere and so the sun shows distinct bands. It would be useful to take a few more photographs with the sun at the same elevation, both in the morning and in the evening. I wouldn't be surprised if the bands are only a rare observation. Dolphin (t) 03:15, 11 August 2010 (UTC)

I don't think this is rare. I'm seeing lots of air pollution in that image, possibly smog or smoke from a wildfire of some kind. The temperature also appears to be above 30 C based on news reports in that region. Although there was a small fire in that area in the morning the photograph was taken, smog is a known problem during the summer, with local reports blaming gas-powered lawn mowers, in addition to wood fires, ATV's and cars. Viriditas (talk) 04:00, 11 August 2010 (UTC)

Now we know where the cutout[21] went. Cuddlyable3 (talk) 09:46, 11 August 2010 (UTC)

More finds

Salamander in question

These small salamanders are found under slabs of rock within several feet of a stream. What are they? They are very common. Most of them have the stripes down the back. --Chemicalinterest (talk) 13:03, 11 August 2010 (UTC)

Reverberation

Lets say I'm voice chatting on my computer using skype or something. And I while we are chatting, I can hear my voice on the other person's computer. Would this "echo" be described as reverb? 148.168.127.10 (talk) 13:24, 11 August 2010 (UTC)

mockingbirds

why do mockingbirds open their wings repeatedly while searching for bugs in the grass?--Horseluv10 13:27, 11 August 2010 (UTC)