Wikipedia:Reference desk/Archives/Science/2010 September 14

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September 14

Paint

does oil paint contain surfactants or does only latex --Kj650 (talk) 00:59, 14 September 2010 (UTC)

I'm not sure we can give you a general answer on this one. Some oil paints almost certainly contain something which acts as a surfactant: I can say that because there are a huge number of substances which act as surfactants, and the composition of oil paints is very varied, depending not only on the manufacturer but also on the pigment being used. Physchim62 (talk) 01:28, 14 September 2010 (UTC)

How did the San Bruno pipe explode?

How did the pipe explode? There's no air underground, and natural gas has a Flammability limit of between 4.4 and 17%. So it needed a lot of air. Natural gas is also lighter than air, so any leak not in an enclosed location will rapidly dissipate. (Obviously we don't have definitive answers, but anyone have any speculation?) Ariel. (talk) 02:48, 14 September 2010 (UTC)

2010 San Bruno explosion#Investigation WikiDao ☯ (talk) 02:57, 14 September 2010 (UTC)

That doesn't answer the question. Natural Gas does not explode without air. Ariel. (talk) 04:20, 14 September 2010 (UTC)

That only happened five days ago. The official reports won't have been written yet, and news reports don't really give any indication that anyone has had any solid conclusions. I don't think they've even had time to completely rule out foul play.

However, it's clear that the pipe had been leaking for weeks. Seem to me (a complete non-expert) there was plenty of opportunity for gas/air mixing. It's just a question of where. Probably under the street, the explosion doesn't have to have happened literally within the pipe. APL (talk) 05:54, 14 September 2010 (UTC)

Oh, And your assumption about there being no air underground could easily be very wrong. Google Street view shows structures on the road nearby that could be manhole covers, so there may have been maintenance crawlspaces down there. Those would have air in them. As would the storm drains. Who knows where that gas was getting into. APL (talk) 06:08, 14 September 2010 (UTC)

How did geocentrists explain the Midnight sun?

I am taking about the pre-17th century geocentrists not the mordern ones. Were they even aware of the phenomenon? --Diwakark86 (talk) 12:02, 14 September 2010 (UTC)

• Aware? The monks who settled in the Arctic definitely were aware of it. Being aware of something may lead a modern person into questioning the scripture, or the wisdom of its interpreters, but the people "pre-17th century" did not cross this line. They just lived in harmony with nature and scripture, and usually these were very short lives. East of Borschov 12:22, 14 September 2010 (UTC)

I am sure pre-17th century geocentrists were aware of the phenomenon - Tromsø, for example, has been settled since medieval times and is north of the Arctic Circle. I am not clear why you think they would have any problems explaining it. Gandalf61 (talk) 12:28, 14 September 2010 (UTC)

Why is the midnight sun any harder to explain away than the observation of stars "moving in circles" around Polaris? I don't see that it conveys any new information on celestial mechanics that couldn't be "understood" from the frameworks of the age. Dragons flight (talk) 12:33, 14 September 2010 (UTC)

What Gandalf61 and Dragons flight said. Students of astronomy were well aware that the ecliptic is in a different plane from the celestial equator; and that tilt is the reason for the phenomenon of the midnight sun, whether one thinks that the apparent movement of the sun is due to its being impelled daily around Earth while having a slower retrograde revolution of its own or due to Earth's rotating on its axis while revolving around the sun. We still, for many purposes, use the celestial sphere (as illustrated in the ecliptic article) to specify the positions of celestial objects, even though we don't think that it models the physical reality. Deor (talk) 13:05, 14 September 2010 (UTC)

Thanks for the link to Ecliptic article. I always thought the geocentic model had a fixed orbit for the sun, forgot about the seasonal shifts in the apparent orbit of the sun. Yes, anything that wold explain the shifts in sun's orbit around the earth would explain the midnight sun. Thanks for the clarification. --Diwakark86 (talk) 13:43, 14 September 2010 (UTC)

Pre-Copernican geocentric astronomers went through some pretty complicated hoops to make their measurements consistant with a geocentric universe. Entrenched theories are surprisingly resiliant; people are VERY resistant to abandoning them, and will often do some pretty bizare things to make data fit an existing theory, instead of changing or abandoning the old theories. See Deferent and epicycle and the Ptolemaic system in general to see the complex mathematics and geometry used to generate a model of the universe which kept the earth at the center and STILL fit the observations. And lest we get smug and think that modern scientists are less likely to do such mathematical gymnastics to avoid abandoning old ideas, see Cosmological constant for a similar bit of data that Einstein inserted into his General relativity so that he didn't have to have an expanding universe. It's pretty clear that any bit of data which appears to contradict the geocentric universe can STILL be twisted slightly to fit it. Any system which can come up with epicycles to explain away planetary movement can similarly explain the midnight sun. It should be noted that its not that hard to do. If the sun moved around the earth at an angle to the equater equivalent to the difference in angle between the earth's revolution and rotation (22.5 degrees), then the effect on seasons and on things like the midnight sun would be identical. You don't need a heliocentric system for effects like that. If we swap the positions of the objects, the effect of light on the earth would be identical. Johannes Keppler is credited (perhaps apocryphally) with commenting to his students that if the heliocentrists had been right, everything would have still looked roughly the same, given the pre-telescope level of observational skill. --Jayron32 17:00, 14 September 2010 (UTC)

I just want to point out that by even in Galileo's lifetime, the Ptolemaic model had been more or less gotten rid of, and the debate was really between the Copernican model and the Tychonic system. There wasn't any empirical way to really effectively distinguish between the two models until the 19th century, when the stellar parallax could be observed. There are ways to distinguish between the Copernican and the Ptolemaic (e.g. the phases of Venus). --Mr.98 (talk) 23:52, 14 September 2010 (UTC)

alcohol

good day to all,why do they add alcohol to benedictine d.o.m.Some religions do not allow the followers to take anything with alcohol added, so it becomes difficult for them to consume it, but because of the herbal value we wanted to drink it.They could invent a drink without the alcohol in it, cant they?TQ —Preceding unsigned comment added by 175.144.126.209 (talk) 13:33, 14 September 2010 (UTC)

You wouldn't have the same drink without the alcohol. In making a herbal liqueur like Bénédictine, you are dissolving out various chemical compounds from the plants, and the compounds have different solubilities in alcohol and water. So they don't "add" alcohol to Bénédictine, it is an essential part of the manufacturing process. Physchim62 (talk) 13:58, 14 September 2010 (UTC)

Yes, there are many things that do not dissolve in water such as iodine that dissolve in alcohol. If the drink did not have the alcohol, the chemicals would not be in the drink. --Chemicalinterest (talk) 15:12, 14 September 2010 (UTC)

Maybe the OP would prefer drinking ethyl acetate or acetone or methylene chloride. John Riemann Soong (talk) 20:12, 14 September 2010 (UTC)

I don't think the stuff is intended as medicine! You might as well ask why they don't make whiskey without alcohol. Some religions don't allow consuming alcohol, but that is not the responsibility of Catholic monks, whose religion does allow it. --Trovatore (talk) 18:44, 14 September 2010 (UTC)

It was originally: "At the Benedictine Abbey of Fécamp in Normandy, monks had developed a medicinal aromatic herbal beverage." Many alcohols were some still are. Mouth washes and cough syrups still may contain ethanol. Not too far removed from the dozens-of-herbs liqueurs or the old "rock candy in whisky" home version. Even root beer and ginger beer have their roots in alcoholic herbal medicine. Also spruce beer. 75.41.110.200 (talk) 04:45, 17 September 2010 (UTC)

Well, they make "beer" without alchohol... Googlemeister (talk) 19:13, 14 September 2010 (UTC)

Yeah, what's that about? --Trovatore (talk) 20:21, 14 September 2010 (UTC)

Most of the alcohol in drinks is created by yeast. Does that mean that bread has alcohol in it before baking? Does any remain after baking? HiLo48 (talk) 23:28, 14 September 2010 (UTC)

Yes, bread has alcohol before baking. A tiny fraction of it will remain, I suppose.

Supposedly that wonderful "baking bread" smell is largely ethanol. There was a to-do about it a few years back, when bakeries in San Francisco were asked to put afterburners on their exhaust, so they didn't release so much ethanol into the atmosphere — it's a component of photochemical smog or some such. --Trovatore (talk) 00:12, 15 September 2010 (UTC)

Would food coloring pass to urine?

Like if all the water you consumed for a number of days had blue food coloring added to it, would your urine be greenish when the yellow urobilin and blue food coloring were present? 20.137.18.50 (talk) 14:55, 14 September 2010 (UTC)

It depends on the food coloring. If it is metabolized, then it will be broken down and the color wouldn't exist. If it is not metabolized, then it would color the urine as well as body tissues it is deposited in. --Chemicalinterest (talk) 15:13, 14 September 2010 (UTC)

Needless to say, most commercial food colorings are carefully chosen to be fully metabolized. No company wants public panic over their product because of strange skin or urine coloration. --Ludwigs2 20:13, 14 September 2010 (UTC)

Beetroot is infamous for this.--Aspro (talk) 15:29, 14 September 2010 (UTC)

See also Methylene blue#As a prank. (Not recommended to try at home, just a historical note.) TenOfAllTrades(talk) 16:22, 14 September 2010 (UTC)

"Urine tracer" is the name I've heard used for food coloring that passes to urine. We don't have an article on urine tracers, so I don't really know what the proper name is. -- kainaw™ 17:48, 14 September 2010 (UTC)

If you're willing to generalize from the visual to another of the five senses, you might also be interested in asparagus. --Trovatore (talk) 20:25, 14 September 2010 (UTC)

Dog limp

request for veterinary advice
The following discussion has been closed. Please do not modify it.
I have a 8 month old Labrador Retriever that recently started to limp on a hind leg. What can it be? He is so young...?? —Preceding unsigned comment added by Petras100 (talk • contribs) 16:11, 14 September 2010 (UTC) Moved to new section. --Chemicalinterest (talk) 16:16, 14 September 2010 (UTC)

I'm sorry, but we are unable to offer medical advice – about humans or about our pets – here at the Reference Desk. You should address any concerns you might have about animal health to a veterinarian or other qualified professional. I hope that your dog feels better soon. TenOfAllTrades(talk) 16:21, 14 September 2010 (UTC)

I just want to reiterate that, aside from the Ref Desk guideline, if the puppy is developing a limp, you should really set up an appointment with the vet. They usually limp for a reason. It might be something temporary and ephemeral, but it's best for you and the dog to get it checked out. --Mr.98 (talk) 01:24, 15 September 2010 (UTC)

I don't think it's appropriate in this case to make a recommendation one way or another. If you value the dog's health and well being, weighted by the risk that this actually needs to be looked at by a vet, are of higher value than the cost of a veterinary visit, then sure, go ahead and make an appointment. But if the costs of a vet visit are higher than the value of the dog to you (again, weighted by the chance that this actually requires a vet visit), then it might be better to forgo a visit and save your cash. Even pets that we value very dearly have a finite value associated with them, and we shouldn't pretend otherwise. These value judgments are ones that only the OP can make, not any of us. Buddy431 (talk) 16:06, 15 September 2010 (UTC)

Phenphedrine Pills

request for medical advice
The following discussion has been closed. Please do not modify it.
im 16 And im Taking Phenphedrine Pills What Can Happen ? Cause The Warning Says You Most Be 18 —Preceding unsigned comment added by Joselin1809 (talk • contribs) 18:37, 14 September 2010 (UTC)

I'm sorry, but we are unable to offer medical advice here at the Reference Desk. You should address any concerns you might have about pills to a doctor, pharmacist. or other qualified professional. --Tagishsimon (talk) 18:38, 14 September 2010 (UTC)

If your medication says don't take unless you're an adult, you should take heed of that warning. See a qualified medical professional for the proper contraindications of that medication. Regards, --—Cyclonenim | Chat  20:08, 14 September 2010 (UTC)

Actually, this is appears to be an herbal supplement, not a medication, at least in a legal sense. We don't have an article on Phenphedrine - maybe we should start one. According to the apparent manufacturer web site [1] it contains:

mg	ingredient	blather
250	DiCaffeine Malate	"an ultra potent multi-dimensional ingredient that combines all natural Caffeine with Malic Acid into an ionic bonded compound"
100	Hops	"Extracted from Humulus Lupulus is an alkaloid called Lupulinum, which produces a mild stimulant effect which then triggers the body to relax."
50	Chocamine™	"A proprietary extract of the Columbian cocoa plant. It contains numerous constituents including methylxanthines (theobromine, caffeine, and theophylline), biogenic amines (phenylethylamine, tyramine, and according to one source, synephrine), amino acids (phenylalanine, tryptophan, tyrosine, others), minerals (with a high content of magnesium), numerous beneficial antioxidants, and possibly some non-psychoactive cannabanoid-related compounds.
50	Razberri-K™	"In a recent study (Morimoto et al, 2005), test subjects were fed a high fat diet to induce obesity while treated groups were also fed an additional 1 or 2% raspberry ketone."
50	Ginger 20% Gingerols	"Used in ancient China for centuries..."
20	Phenylethylamine	"PEA is an amphetamine-like substance that shares relations with the naturally occurring catecholamine neurotransmitters and their amino acid precursors, tyrosine and phenylalanine. It may be one of the chemicals in the brain that promotes pleasure and euphoria. Some call PEA "the Love Drug" and it is extracted from chocolate and is responsible for the aphrodisiac-like reaction people have while consuming chocolate."
15	Evodiamine 98%	"Several studies have shown that it reduces both fat uptake and burns the fat inside the body. Thermodiamine appears to support an increase in lipolytic (fat burning) activity through several mechanisms. Evodiamine appears to affect receptors known as vanilloids. These receptors are involved in the regulation of body temperature.
15	Sclareolide 98%	"This supplement has excellent thermogenic properties and is used to aid in weight loss. It supports an increase in the rate of lipolysis (fat burning) activity through Cyclic AMP...."
15	1,3 Dimethylamylamine (DMAA)	"resembles the body’s chemical messenger epinephrine, also known as adrenaline. Like adrenaline, 1,3-Dimethylamylamine is a powerful stimulant, that suppresses appetite, burns fat, boosts energy and increases physical performance...
3	Yohimbine	"Yohimbine decreases body fat and increases muscle mass. Yohimbine is an alpha 2-adrenoreceptor blocker and a monoamine oxidase inhibitor, which increases serum levels of norepinephrine...
50	Chocamine	"naturally contains Tryptophan – an amino acid which increases brain levels of serotonin (a calming neurotransmitter), and is commonly used to combat stress and depression."

Now, the whole purpose of the medication is to stimulate Cocaine and amphetamine regulated transcript (CART), with the first two letters standing for cocaine and amphetamine ... which does make one wonder about the safety of it, but also whether it might have a chance of working. With the comparison of an ingredient to amphetamine above, and the various claimed psychoactive and health benefits, I'll be surprised if they don't end up being persecuted under the Analog Act, let alone a spanking by the FDA. Worrisome little things like the MAOI aside, what we're talking about here is 2-3 coffee cups worth of caffeine, which has its own health effects.

We don't give medical advice, but I hope this will encourage you to research compounds further and make informed decisions.

Also note that under DSHEA in the U.S. the supplement makers are not required to provide the full quantities of all the things they say are in it, so figuring the reputation/quality is ... difficult, to say the least. Wnt (talk) 20:50, 14 September 2010 (UTC)

It looks to me like the pill contains as much caffeine as a cup of strong coffee, plus a bunch of other things at levels too low to have much of an effect. Looie496 (talk) 22:33, 14 September 2010 (UTC)

Woah guys, whilst I suspect that what you're saying is true, we don't know anything about the OP. Caffeine can be pretty dangerous for some people with certain heart problems. Besides that, there are other things in this stuff which causes concern. Yohimbine can be potentially quite dangerous. Phenethylamine is quickly metabolised, so unlikely to have an effect as an MAOI as mentioned above. Again, I'd reassert that the best thing for the OP to do is to consult a doctor. Regards, --—Cyclonenim | Chat  23:47, 14 September 2010 (UTC)

To dig a little deeper, yohimbine hydrochloride pills (Yocon) are 5.4 mg, [2] and usage is typically at least three of these daily [3]. So the amount in this supplement may be less than in the pharmaceutical usage (especially if it doesn't really have any...). What's a little more interesting as a question, is whether under DSHEA, it would be permissible for the pill to contain more yohimbine than it says on the label. Wnt (talk) 18:50, 15 September 2010 (UTC)

I wouldn't have thought so. I think DSHEA refers to the idea that you can choose not to disclose quantities. If you do, I'm sure putting anything other than the disclosed amount in the pills would be construed as deception. Regards, --—Cyclonenim | Chat  20:46, 15 September 2010 (UTC)

"We use an ultra potent multi-dimensional ingredient that combines all natural Caffeine with Malic Acid into an ionic bonded compound optimizing energy," hahahahahaha. Does the malate really do anything to improve bioavailability? John Riemann Soong (talk) 00:35, 15 September 2010 (UTC)

That's awesome. I hope not all their ingredients are multidimensional, by the way. They might have something to contribute to my understanding of chemistry if not. Comet Tuttle (talk) 17:23, 15 September 2010 (UTC)

Spin

Question: "In a uniform magnetic field B determine how the energy of a spinning charged particle with magnetic moment μ changes as I change the orientation of the spin with respect to the magnetic field. Plot the result."

(NB: This is a for a quantum physics class). So classically, the energy would be something like -μ•B = |μ||B|cosθ, so I would just plot some sort of cosine curve. But I'm assuming we're supposed to treat spin as quantized, so would the energy be something like ±(a/2)$\hbar$*|B| (a = gq/2mc)? But how would I plot this? And wouldn't, in the process of changing the orientation of the particle, I be making repeated measurements of its spin? So shouldn't the energy continuously alternate between ±(a/2)$\hbar$*|B|? 74.15.136.172 (talk) 19:59, 14 September 2010 (UTC)

• Because of the quantization you cannot measure the spin direction in a continuous way, just whether parallel or antiparallel to the field. So perhaps you just need a bar graph with two bars at 0 and 180 degrees. In a probabilistic way, or in a bulk material you could get a probability or average though. Graeme Bartlett (talk) 10:54, 15 September 2010 (UTC)

How does a geographer define "mainland"?

There is an RFC at Talk:Lower Mainland on how exactly mainland is defined, and whether islands in a river delta are considered part of the "mainland". I'm not looking for opinions on how to parse the various dictionary definitions, rather my question is: if a geographer sat down to draw one single line around the "North American mainland", what criteria would they use to decide where to draw the line? Thanks for any help! Franamax (talk) 20:49, 14 September 2010 (UTC)

As I understand it, 'mainland' is mostly a colloquial definition, not an analytic one. anything part of the contiguous 48 states (including coastal islands) would be considered US mainland, though there may be regional uses of the term (e.g. residents of Martha's Vinyard might talk about the Massachusetts mainland). --Ludwigs2 21:09, 14 September 2010 (UTC)

As a "geographer", what I would do is establish at the outset which stretches of tidal waters are so narrow that they should be discounted - that is, crossed by a defining straight line - so that any areas of water inland of that line should be defined as mainland. Ghmyrtle (talk) 21:22, 14 September 2010 (UTC)

That's my idea too, modified a bit to include attention to where the concentrrations of fresh- vs sea-water are, magnitude of tidal effect (how to draw the line at an estuary say), physical geography of the ground underlying the "seawater". I was hoping for a link to a scholarly document or textbook to read through, there must be some kind of general principle, geographers must have discussed this at least once somewhere, right? ;) Franamax (talk) 00:48, 15 September 2010 (UTC)

Not necessarily - it's not something that seems important. There may be some definitions out there done for particular purposes in particular places, but there are unlikely to be any wider guidelines. Ghmyrtle (talk) 06:15, 15 September 2010 (UTC)

[I do not have an answer, but I wish to mention Manitoulin Island and the island of Montreal, also Honshū and Okinawa Island.

—Wavelength (talk) 16:07, 16 September 2010 (UTC)]

Does anal sex occur between male and female animals?

The article homosexual behaviour in animals states that anal sex between two male animals has been observed to occur. What I want to know is, has anal sex between a male and a female been observed in non-human animals, and are there any accounts thereof or information on its frequency? You may find this an obtuse, frivolous, perhaps even juvenile question, but it's something that I am genuinely curious about and there is no information on the topic that I can find in Wikipedia. Animal sexual behaviour and anal sex appear to have nothing. I will guess that it has probably happened, but are there any accounts of it in animals?--Whelkberet (talk) 21:13, 14 September 2010 (UTC)

I agree this is a reasonable enough question, I don't know the answer myself and it’s definitely NOT something I'm going to start researching at work! Lol.. However I'd encourage you to consider what the implications of the answer is either way. IMHO, I don't see that this would really "prove" anything. The vast majority of the animal kingdom do not engage in sex the way humans do. For most animals, except maybe a small handful which are mostly primates and dolphins, the act is pretty much purely for procreation. As far as we can tell, it's not "natural" to copulate for pleasure or recreation, we are amongst the few exceptions to the rule. I personally have an intense dislike for the "it's not natural" argument. Especially when it's religious people who use it against homosexuals. Not only do plenty of animals exhibit homosexual behaviour in nature. But "nature" is dropped like a hot stone when it doesn't suit them, like to explain miracles and creation. That's my new argument against "creationism", it's not "natural", lol…Vespine (talk) 23:17, 14 September 2010 (UTC)

And just to present a reference to my rant, it's called the naturalistic fallacy. So even if it is "not natural" in just joins the list which also includes democracy, science and even religion it self as human pursuits which are "not natural". Vespine (talk) 23:29, 14 September 2010 (UTC)

Many religious people argue that religion and even god-belief is universal. Imagine Reason (talk) 23:09, 16 September 2010 (UTC)

According to Bruce Bagemihl, Biological Exuberance: Animal Homosexuality and Natural Diversity, page 287 (via amazon), orangutans have been observed to participate in anal sex in heterosexual couplings. Botos will apparently have heterosexual encounters that involve blowhole penetration. (Page 341, which includes diagrams.) The book is primarily about homosexual animal sex so there are only fleeting references to "non-reproductive heterosexual behaviors" but there are a couple to start you off. The book (from what I've skimmed of it on the Amazon preview) is pretty interesting/odd. The animal world has a lot more variety of sexual behavior than most people recognize, I think. Pretty much anything you can imagine and more. It would be a little inappropriate to say that the blowhole sex "blew my mind" but there you have it. --Mr.98 (talk) 23:39, 14 September 2010 (UTC)

Bonobos will engage in pretty much any kind of sex act you can imagine so, while I don't have an explicit reference to heterosexual anal sex, it's a fair bet that they engage in it. Physchim62 (talk) 02:53, 15 September 2010 (UTC)

I observed Bonobos at a zoo in San Diego engaging in varied couplings such as this, which Moms tried to explain away to their children. Edison (talk) 04:43, 15 September 2010 (UTC)

I looked first, naturally, for bonobo references, but did not find any references to heterosexual anal penetration. In general it looks like heterosexual anal penetration in the "animal kingdom" is much more rare than homosexual anal penetration. No big surprise there. No need for reading any human implications into it, of course. If we decide what is "natural" for humans based on what other animals do, we should all be having mass orgies, raping one another left and right, eating each other's children, having sex with each other's noses, cling to our mates for our whole lives, and things of that sort. The "natural" world is a horrible place to try and look for "natural" human behavior. You can find basically anything one might like and dislike (and much one could not even imagine having an opinion on) replicated in the wild amongst the millions of species of nature's funny critters. --Mr.98 (talk) 13:23, 15 September 2010 (UTC)

In a documentary on treefrog reproduction that I saw many years ago, there was a comment about their rampaging orgies. There is so much sex going on in a confined area that there is penetration in pretty much anything that moves and many things that don't. However, this isn't related in any way to the concept of anal sex with humans. To put it on the scale of humans, you'd have to through about a thousand women and a thousand men into a warehouse, grease them all up, and tell them to go at it. Any anal sex that happens is purely by chance, not by design. -- kainaw™ 13:31, 15 September 2010 (UTC)

Egg without yolk

If an Egg (biology), especially a chicken egg, is laid without a yolk, as I have often seen, and then fertilized, what will happen to the egg? Will an embryo never develop or will it starve to death? --The High Fin Sperm Whale 21:45, 14 September 2010 (UTC)

The yolk is the embryo. So no yolk, no chick. The white is food for the embryo. Ariel. (talk) 22:07, 14 September 2010 (UTC)

I don't think that's right -- the yolk is food too as I understand it. But it is necessary food. The embryo can't develop without it. Looie496 (talk) 22:25, 14 September 2010 (UTC)

The embryo is separate to the yolk and the white. So I think Looie is right, the embryo develops connected to the yolk which is the primary source of food. The white is mostly for protection and also additional food. I don't think the egg would work without all the parts. Vespine (talk) 23:01, 14 September 2010 (UTC)

You're right, the part that becomes the embryo is called the Germinal disc. I always thought it was the yolk because the blood vessels engulf it, but don't enter the white. Ariel. (talk) 23:48, 14 September 2010 (UTC)

Yes, but the disk is part of the yolk therefore your original answer: "So no yolk, no chick" is essentially correct. 174.58.107.143 (talk) 02:41, 15 September 2010 (UTC)

What may hatch from that egg, however, is something entirely different (see article on cock egg). ---Sluzzelin talk 13:27, 15 September 2010 (UTC)

Wood glue and aluminium foil

I use a sheet of aluminium foil to seal a bottle of yellow wood glue with a broken cap. When I opened it the foil had crumbled into a white powder. Why did it do that? Ariel. (talk) 22:08, 14 September 2010 (UTC)

Something in the wood glue oxidized the aluminum to aluminum oxide. In the future, you may want to use a non-stick, non-reactive paper instead like wax paper (paper coated with paraffin wax) or Parchment paper (baking) (paper coated with silicone). --Jayron32 00:42, 15 September 2010 (UTC)

I figured it did that, but what vapor could do that to aluminium? I know mercury can, but only with contact. This did it by vapor, and it's something in water based glue. Ariel. (talk) 02:47, 15 September 2010 (UTC)

Formaldehyde would do that: the aluminium reduces the formaldehyde to methanol, and the methanol reacts to produce aluminium methoxide. You only need a little bit of formaldehyde, because the aluminium methoxide then gets hydrolyzed by moisture in the air, reforming methanol, and so on. You just need something that will get through the oxide layer on the surface of the aluminium. Physchim62 (talk) 06:51, 15 September 2010 (UTC)

BTW, mercury does not oxidize aluminium; it just dissolves it. --Chemicalinterest (talk) 10:44, 15 September 2010 (UTC)

these not formaldehyde in yellow wood glue thou? its PVA

Hypothetical weight loss question

Suppose that a Fat Man needs to adhere to a 1,500 calorie-per-day diet in order to lose a certain amount of weight. Now suppose the Fat Man eats an average of 1,500 calorie a day, with a very high degree of variance in day-to-day calories intake. To give an extreme example, let's say he eats 3,000 calories every other day and then fasts on alternate days. Will he still lose weight? Will he lose weight more slowly?

We all understand that binge eating is neither healthy nor advisable; I am strictly asking about whether this method could be expected to lead to weight loss.--The Fat Man Who Never Came Back (talk) 22:27, 14 September 2010 (UTC)

As long as you burn more calories then you consume, you will lose weight, full stop. So if you are burning MORE then 1500 calories a day, but only consuming 3000 calories every 2 days, you will lose weight. How quickly and easily it happnes probably depends on a large number of variables, but the primary premise holds true no matter what you do or eat. Vespine (talk) 22:46, 14 September 2010 (UTC)

First, here is an article on it: Intermittent fasting. Second, the body may enter a Famine response response mode, where it works hard to conserve calories, which is counter productive in this case. Ariel. (talk) 23:37, 14 September 2010 (UTC)

We do not give any medical advice. Some people, such as diabetics, might suffer severe consequences from fasting for an entire day. Others could eat only on alternate days and lose weight at a rate similar to that when they ate the average calories every day. In the American Civil War, Confederate General Braxton Bragg, for his convenience, so that the commissary wagons could stay far to the rear. decided to issue cooked rations for three days only every third day, The soldiers in the Army of Tennessee, being somewhat starved when the rations arrived, bolted them down and then starved until the next rations arrived. His soldiers, in general hated him, per "Soldiering in the Army of Tennessee," Larry Daniel, The University of North Carolina Press, 1991, page 54. Edison (talk) 04:33, 15 September 2010 (UTC)

• WP also has a Starvation mode page, it appears to cover the same subject as Famine response. Here is an article on a Weight Watchers site titled "The Starvation Myth". Not sure how reliable it is due to COI. - 220.101 talk^\Contribs 08:52, 15 September 2010 (UTC)

science

1 the angle of the suns rays ith the cause of defferences in temperature at the----and the ------ —Preceding unsigned comment added by 74.235.86.215 (talk) 23:54, 14 September 2010 (UTC)

Sorry, we don't do homework questions here. Looie496 (talk) 00:00, 15 September 2010 (UTC)

But if you read the article: effect of sun angle on climate, you should find your answer. Smartse (talk) 00:05, 15 September 2010 (UTC)

oh, I thought this was MadLibs. I was going to say 'turnip' and 'wheelbarrow' --Ludwigs2 00:06, 15 September 2010 (UTC)

Mad Libs, for the uninformed. What a strange way of passing time. I learn something new every day. Buddy431 (talk) 01:04, 15 September 2010 (UTC)

I don't know if that's a homework question, but it does sound like one. As worded, there are no unique answers. The angle of the sun contributes to temperature differences between numerous pairs of locations. (Actually it's not clear if the question is asking about locations.) There's no way to figure out what the intended answers are from the science! --173.49.12.124 (talk) 11:57, 15 September 2010 (UTC)

Casbah, Hague. --Sean 15:09, 15 September 2010 (UTC)

Also take a look at albedo and atmospheric absorption. ~AH1^(TCU) 22:04, 17 September 2010 (UTC)