Wikipedia:Reference desk/Archives/Science/2009 November 13

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November 13

Hollow pipe stronger than solid bar

Is it possible for a pipe of a given substance (metal, say) to be stronger than an equal-diameter bar of the same substance? Interpret "stronger" as you will, though I'm really interested in bending/buckling strength. --Sean 00:32, 13 November 2009 (UTC)

If the pipe is the same material (no special alloying or special hardening) then it is equivalent to the outermost ring of the solid rod of the same diameter, and I cannot see how removing the center of a solid cylindrical rod could increase its strength. For a given weight per unit length, I would expect the pipe to be stronger than a cylinder of the same weight per length but smaller diameter in resistance to bending/buckling, but perhaps not in tensile strength/resistance to elongation. Edison (talk) 00:38, 13 November 2009 (UTC)

For any cylinder, the neutral axis is at the centre. The stress (which is what you're interested in) varies with WxL/Z for a lateral load, where W is the weight, L the length, Z the section modulus. Z = I/C where I is moment of inertia, C is distance from the neutral axis to the most distant fibre. For a shape with outside radius R, C = R, so all that varies is I. I varies with (R^4 - r^4), r being the inside radius. For the solid rod, r=0, so I is maximum - so the solid rod will always be stronger. As Edison notes though, the material near the centre contributes very little to the strength, so in practical terms a hollow shape is much more efficient in material use. If the load is from only one direction, a vertical hollow rectangle will be even better, since I there is WxH^3/12 - w x h^3/12. The buckling (vertical column compression) equations work much the same way, except there you're using radius of gyration. Franamax (talk) 00:53, 13 November 2009 (UTC)

It depends how you interpret "stronger". For example, a concrete cantilever structure is stronger if it is "ribbed", because less of its material strength is "wasted" supporting its own weight. Bending strength of a metal pipe might actually depend on how the pipe is formed - Edison's suggestion that it is identical to the outer ring of a solid cylinder might not take into account anisotropy or lattice structure. There are ASME handbooks that give empircal measurements for these sorts of parameters for pipes of different materials, wall thicknesses and diameters, because theoretical equations are poor approximations to the real material properties. Nimur (talk) 00:59, 13 November 2009 (UTC)

(ec) The above answers are correct – for a homogeneous cylinder, a solid cylinder will always be more resistant to a given buckling force than a hollow cylinder of the same material and outer diameter. A minor caution applies, however, if one is dealing with a long cylinder supported at its ends. In such a case, the weight of the cylinder itself supplies a bending force which can contribute to buckling. In such a circumstance, the strength-to-weight ratio of the cylinder becomes important, and a hollow cylinder may be 'stronger' (in the sense of being able to support a greater externally-applied force) than a solid one. TenOfAllTrades(talk) 01:08, 13 November 2009 (UTC)

Hmm, that's a good point and it could apply to my example of laying a pipe horizontally and putting weight along its length also. For a material of very low tensile strength and very high density, you could have a situation where you have a perfectly good pipe sitting there, then you stick a slug of extra weight into the middle and it nows sags under the combined weight. The smaller diameter piece you stick into the middle couldn't support its own weight, so it would load the pipe, possibly to failure. I'll have to run some numbers on that one. For a column in compression, I'm not convinced, but those formulas are way more complicated, so I might not get to them. :) Franamax (talk) 02:47, 13 November 2009 (UTC)

The OP said "Interpret 'stronger' as you will." If the pipe or cylinder is hanging down from a support and loaded, the cylinder of greater cross section would support a far greater load than the pipe. Likewise, a vertical cylindrical column should support greater weight than a pipe of the same diameter if loaded. If the member is used as a beam, and runs horizontally between supports while supporting a distributed load (like a joist or beam in a structure), only if the supported load is small relative to the weight of the member will a hollow member be "stronger" than a solid one. I agree that it is possible, depending on material , that a hollow horizontal member supported at one end or at the ends might be able to extend farther without collapsing than a solid one, if it were heavy and of low tensile strength (like what? Unreinforced concrete? Adobe? Sod? Playdough? Modelling clay?). I'm not sure that would apply to steel or wood. Joists or beams are solid, not hollow, and that is not a mistake. Edison (talk) 05:16, 13 November 2009 (UTC)

Interestingly, our pipe article has an illustration of wooden pipes, and concrete pipe is very common. Clay pipes are commonly used in many parts of the world; I doubt that they are suspended or supported only by their own material strength. Nimur (talk) 17:53, 13 November 2009 (UTC)

Neither the historic (19th century use) of wooden pipe or more recent use of concrete pipe to carry water or other liquids supports any claim that the pipe is stronger than a solid cylinder of the same diameter, particularly when in compression as a column, where the compression strength of concrete would be great. Unreinforced concrete would not do well in tension, but wood would, and I would vote for the solid cylinder in tension or shear strength. The outermost part would be more effective against buckling or in torsion than the same mass of material located near the center. Edison (talk) 20:59, 13 November 2009 (UTC)

metals and stones

ok, i have several question, but theyre all related to each other, and i did found the general asnwers, but those werent realy specific, especially since my question are actually quite specific anywaysm here goes (by the way, all of the questions are about natural, un-mixed [not artificcially made or alloyed] metals and just natural stones [doesnt matter if its carbon mixed with any other element, as long as its natural])

1. which metal AND stone have the highest melting point?

2. which metal AND stone have the highest (and lowest) density?

3. which metal AND stone have the best heat conduction? (dont answer this one if the answer is silver and diamond)

4. which metal is the hardest (non brittle) and/or toughest (hard to break, crack, bend, or dull) (?possibly based on mohs scale?)

thats it for now, i apologize if this the wrong way to do it, and i want to thank the person who is going to answer this in advance —Preceding unsigned comment added by RoYaLKiD90 (talk • contribs) 01:45, 13 November 2009 (UTC)

Category:Lists of chemical elements is a good start for finding many of the metal properties. Not quite sure what you mean by "not artificcially (sic) made" for metals...almost no metals exist in their "normal, metal form" in nature, but rather as oxides, sulfides, or other minerals and ores. However, Periodic table (standard) tells you which elements are naturally-occurring vs only known via nuclear synthesis in labs. DMacks (talk) 02:55, 13 November 2009 (UTC)

For the lowest density stone, perhaps a pumice stone ? StuRat (talk) 03:05, 13 November 2009 (UTC)

If it has to be a naturally occurring metal then osmiridium is a natural metal alloy of osmium and iridium, high melting and dense. Osmium is the hardest metal and also very slightly denser than iridium, or osmiridium, I am not sure that you will find it pure in nature though. But Osmium is also slightly brittle. reading Thermal conductivity and the condition on your question means that it should not be answered with diamond, but diamond is not actually a metal anyway. And silver is the top metal in thermal conductivity, and also does occur naturally. Graeme Bartlett (talk) 09:37, 13 November 2009 (UTC)

chicken and the egg

Is the DNA of the egg from whence the chicken comes identical to the DNA of the chicken it hatches? 71.100.0.254 (talk) 01:59, 13 November 2009 (UTC)

No. Chickens reproduce sexually, so the DNA of the chick is a combination of the DNA of hen and the DNA of the cock. --Tango (talk) 02:00, 13 November 2009 (UTC)

...er ...No, I don't mean the DNA of the chicken that lays the egg. I mean the DNA of the egg from whence the chicken comes. 71.100.0.254 (talk) 05:33, 13 November 2009 (UTC)

You may also be interested in Chicken or the egg. Red Act (talk) 02:18, 13 November 2009 (UTC)

It is an interesting page, certainly, but it has nothing to do with the OP's question. --Tango (talk) 02:20, 13 November 2009 (UTC)

Are we talking about a fertilized egg or an unfertilized egg? Bus stop (talk) 02:21, 13 November 2009 (UTC)

That depends on why the question was asked. Given the title of the question, I suspect the OP is planning on using a genetic argument to answer the riddle of whether the chicken or the egg came first. Genetically, the answer to the riddle is that the egg came first: Regardless of what precise set of criteria is used to distinguish between "chicken DNA" and the DNA of the chicken's progenitor species, the first egg that contained "chicken DNA" existed before the first bird that contained "chicken DNA". That point is made in the article I linked to.

The "no" part of your answer, BTW, is incorrect. The OP is comparing the DNA of an egg to the DNA of the chicken that comes from it, not comparing the DNA of a chicken to the DNA of an egg it lays. Red Act (talk) 03:14, 13 November 2009 (UTC)

The DNA within the egg is the same as the DNA as the chick that ultimately hatches from the egg. Technically the egg is the zygote - the first cell that forms from merging of male & female genetic material. From the DNA in that cell, the egg and the chick are formed...hence the DNA within the egg is the same as for the chick. On the other hand, the DNA in the egg is NOT identical to the DNA in the chicken that lays the egg because half of the DNA came from the male bird. SteveBaker (talk) 02:48, 13 November 2009 (UTC)

Unfertilized eggs don't contain any genetic material from the male. Bus stop (talk) 02:55, 13 November 2009 (UTC)

And if, perhaps, you asked in order to speculate on the common idiom which came first, the chicken or the egg -- I will respond to that. The question, when posed with thought, may be used to ask how and when evolutionary changes occur. Germ line mutations would allow a a pre-chicken to lay an egg which contains an organism unlike itself, thus it can be said that the [chicken] egg preceded the chicken (and, in essence, the pre-chicken, surprisingly, did not lay a pre-chicken egg). It can also be speculated that the developing, intra-egg pre-chicken developed a somatic mutation (that also affected it's germ-line), thus suggesting that the chicken preceded the chicken egg (because what the pre-chicken laid was a pre-chicken egg). DRosenbach ^{(Talk | Contribs)} 03:55, 13 November 2009 (UTC)

Chicken and egg question is addressed in Scientific American magazine, September 2009, page 77. Bus stop (talk) 03:47, 13 November 2009 (UTC)

The answer I am seeking would be the same answer as if I asked about a caterpillar and a butterfly. Also please clarify about the contents of the egg. It is my understanding that only one sperm enters the egg and therefore the contents of the egg after fertilization leaves no male DNA since it has combined completely with the femaile DNA... but of course what I mean is the combined DNA not to include a remnant of the males DNA. 71.100.0.254 (talk) 06:03, 13 November 2009 (UTC)

A butterfly has the same DNA as the caterpillar that it developed from. In general, the DNA of an animal doesn't change during a metamorphosis.

During sexual reproduction, roughly half of the DNA in the fertilized egg comes from the mother, and half comes from the father. In addition to the articles I just linked to, you may also want to read meiosis. Red Act (talk) 06:33, 13 November 2009 (UTC)

How many nuclei or cells are even in an unfertilized egg laid by a chicken? Are there any? -Craig Pemberton 07:48, 13 November 2009 (UTC)

An unfertilized egg (an ovum), being a gamete, consists of one haploid cell. This is in contrast to a just-fertilized egg (a zygote), which consists of one diploid cell. For a chicken's egg, the nucleus is in the germinal disc, which is that white spot on the yolk. Red Act (talk) 08:38, 13 November 2009 (UTC)

Deaths caused by malaria?

It's easy to find how many people die from malaria per year in modern times but I can't seem to find any numbers for a few hundred years back. I understand malaria has existed for an insanely long time but does anyone know about how many people have died from it in the past few centuries? —Preceding unsigned comment added by 99.230.206.44 (talk) 02:04, 13 November 2009 (UTC)

Since there really wasn't a precise way to analyze total deaths by any disease up until about 1850, it's difficult to give exact numbers. To be honest, I believe the way that diseases like malaria were recorded by text, but not typically, and especially in the most infected lands like Africa. If I were to estimate, I would take the total number of malaria-related deaths in today's population and make adjustments according to population and infectibiliy. For example, if 881,000 people died in 2006 from the disease, I would find the approximate population of a period in time and (do a little math) find the approximate number of deaths that could have occured. It's not precise by any means, but it's better than just guessing right? I hope this has helped!

Try this for information about malaria in general --> WHO malaria website Letter ⁷ 07:33, 13 November 2009 (UTC)

Letter 7, you're suggesting to compare apples and oranges... though I'm not even sure which oranges. :) What is the population you want to compare to which? World population today to world population back then? Not only will you have to rely on wild guesses again (how many people really lived in a specific area at a specific time?), but you also suggest that the same percentage died of malaria. That's highly unlikely assumption. The whole point of malaria medication is to reduce the infection and the death rate. Add to that improved means to protect yourself from mosquitoes (ranging from screens to all the little accessoires that supposedly keep them away), improved health care in general, improved transport (to get health care to people or vice versa), etc. etc. etc. Not to mention that people today live in different areas (more or less exposed to malaria/mosquitoes?), that human activity has had an impact on malaria/mosquitoes, etc. It's actually a pretty interesting question to wonder how much the death rate decreased. But it makes it impossible to assume that the same percentage of the population died, say, in 1700 and today!!

And one more tiny problem to find out "any numbers for a few hundred years back" - malaria is particularly virulent in areas, which "a few hundred years back" simply kept no written records. For example, I don't know if any Sub-Saharan African peoples at all recorded any numbers about malaria deaths before Europeans stepped in (and, BTW, pretty soon started influencing them). So you'll most likely have to look at records of early explorers, missionaries, etc. ... which are most likely seriously flawed (because they commonly only knew a small percentage of the population of today's countries), but it may be your best guess yet... --Thanks for answering (talk) 12:24, 13 November 2009 (UTC)

Also, malaria ranges have shrunk. Washington DC used to be a malaria infested swamp, but I doubt anyone catches it there anymore. Same with most of the rest of the US. It is probably not a common thing to catch in a lot of areas where it used to run rampant. Googlemeister (talk) 14:08, 13 November 2009 (UTC)

Funny you should use that specific example, since there were 2 autochthonous cases near Washington DC in 2002: PMID 12403407 -- Scray (talk) 02:44, 14 November 2009 (UTC)

If you google "malaria 19th century" you get some hits, like this page, that give some indication of what we know about the spread and likely prevalence of the disease in the last couple of centuries. Obviously, exact statistics will not be available for the whole world. (Though for specific countries or regions, they may be—England kept very good death statistics going back hundreds of years.) --Mr.98 (talk) 14:35, 13 November 2009 (UTC)

I imagine you could get very rough estimates of historical mortality rates by studying how much of a population has Sickle cell trait.John Z (talk) 03:34, 14 November 2009 (UTC)

Is this a springtail?

I found this little guy [1][2] in northern Arizona in August. There were several hundred under some pots near a leaking hose so the surrounding loess was damp and shaded. The local region is very arid but there are some reservoirs nearby and scrub and sage not too far out. They were all about 1/2mm long. They could jump about 3cm. I think it might be a springtail but I don't know how to tell for certain. I can't make out a furcula but it is hard to see in the photo. Thank you very much. -Craig Pemberton 03:01, 13 November 2009 (UTC)

If it looks like a springtail and it jumps like a springtail... yeah, I guess it's a springtail :) . --Dr Dima (talk) 03:26, 13 November 2009 (UTC)

My best guess puts it in Entomobryomorpha after looking at a lot of images of springtails. I think I'm confident enough to upload and tag it on commons. -Craig Pemberton 07:51, 13 November 2009 (UTC)

Any springtail that can only jump 3 cm would be laughed out of the club by the other members. StuRat (talk) 11:34, 13 November 2009 (UTC)

Not really, no. Most springtails are tiny, so for some of them 3 cm may well be over 100 times their body length. They can jump several inches, or sometimes less, depending on the species. The peak velocities and accelerations of springtails during the jump are a few times lower than those of fleas, click beetles, and grasshoppers [3]. --Dr Dima (talk) 22:20, 13 November 2009 (UTC)

The fine folks over at bugguide.net identified it as a Entomobrya unostrigata, which I've discovered to be an excellent website for those trying to identify arthropods. Also, I'll pass on this interesting tidbit:

The furca is hard to see in alive specimens since it is held underneath the body when not used. If you tease a specimen for a while and you can keep it jumping it will get exhausted after a series of jumps and then the furca will be visible as a kind of tail behind the body. ---Frans Janssens

-Craig Pemberton 09:49, 14 November 2009 (UTC)

p+ and p- mitochondrial genomes

What do p+ and p- refer to in respect to mitochondrial genomes? ----Seans Potato Business 11:28, 13 November 2009 (UTC)

p+ is a wild type circular mitochondrial DNA, while p- is a mutant DNA.--Gilisa (talk) 13:43, 13 November 2009 (UTC)

I think they are asking which gene is "p" and what is its function. --Mark PEA (talk) 15:57, 13 November 2009 (UTC)

LHC

How the LHC works? When it will start again? —Preceding unsigned comment added by ZrslX009 (talk • contribs) 11:55, 13 November 2009 (UTC)

Did you try LHC which says "Due to the time required to repair the resulting damage and to add additional safety features, the LHC is scheduled to be operational in mid-November 2009.[6][7]" and has a large section at Large Hadron Collider#Design with many links? If you don't already, you'd likely also need to know how Particle accelerators work in general first Nil Einne (talk) 12:10, 13 November 2009 (UTC)

Leukemia transfusions

For patients with luekemia, couldn't they treat it by just doing constant transfusions ? If they don't do this because it would drain the local blood supplies, how about if friends and family (with the proper blood type, of course) provided all the blood ? This would work especially well for pediatric cases, as the quantities of blood needed would be less. I realize that this wouldn't cure the disease, but I would think the patient could be kept alive as long as the transfusions continued. Not a medical advice Q, as I don't know anyone with this disease. StuRat (talk) 15:35, 13 November 2009 (UTC)

Supportive transfusions are a regular part of leukemia treatment. Generally, specific blood components (often red blood cells or platelets, though occasionally white blood cells for immunocompromised patients) are transfused to respond to specific deficiencies, rather than whole blood. Unfortunately, there are issues which would complicate treatment by perpetual transfusion. Patients who receive frequent transfusions of platelets (for example), may develop an immune response to 'foreign' platelets (in appropriate jargon, they are refractory to platelet transfusion: [4]). Finding appropriate HLA type-matched platelet donors is far more challenging than finding ABO-type matches for red blood cell transfusions. Consequently, (potentially-curative) chemotherapy and stem cell transpant are considered a much-preferred alternative to a lifetime of transfusion. TenOfAllTrades(talk) 17:40, 13 November 2009 (UTC)

I've taken the liberty of changing the title of this thread, as it contained a typo, "luekemia" instead of "leukemia". I'm doing this because I'm about to tag the "Luekemia" redirect page for deletion. We don't normally have redirect pages for typos, and I change the title to avoid a redlink.--NorwegianBlue ^talk 21:45, 13 November 2009 (UTC)

I think you are wrong -- we do in fact "normally have redirects for typos". See for example the {{R from misspelling}} template and its associated category. I have removed the speedy tag. --Trovatore (talk) 22:39, 13 November 2009 (UTC)

If you read our leukemia article carefully, you will realize that leukemia is not a single disease. It is a term that includes most or all malignant diseases of stem cells in the bone marrow. Therefore, the prognosis will depend very much on the specific type of stem cell involved, and on the age of the patient. In contrast to many other types of cancer, leukemia is always disseminated at the time of diagnosis. So you have all the problems of a disseminated cancer - a cell population that does not respect our body's normal regulatory mechanisms of cell proliferation. The cells are not localized to a specific area, and therefore not accessible to surgical excision. In addition, there is great variation in prognosis depending on cell type and patient age. Leukemic cells displace normal bone marrow cells. This will, as you address in your question, lead to anemia, and to thrombocytopenia, as TenOfAllTrades says, because megakaryocytes too are displaced. Both the anemia and thrombocytopenia can be treated by transfusion. In countries where leukocyte filtered blood products are mandatory, platelet refractoriness is seen mostly in women who have been immunized through pregnancy. Platelets, in the absence of white cells, are not very immunogenic. A blood center that has a reasonably sized pool of HLA-typed donors and that tests the exact specificity of the HLA-antibodies, will in the vast majority of cases be able to provide matched platelets to such patients. However, the bone marrow suppression also leads to immune suppression, which leads to opportunistic infections, which are a major killer. As TenOfAllTrades wrote, the only potentially curative treatment is chemotherapy, that kills most or all malignant cells, followed by a stem cell transplant. --NorwegianBlue ^talk 23:02, 13 November 2009 (UTC)

Picture of ferrofluid in oil

Hi clever science ref deskers, I'd like to pick your brains about this file: File:Ferrofluid poles.jpg (see thumb). Specifically, the image shows ferrofluid in oil, collecting near the poles of a magnet that has been placed underneath the dish. Although it depends on the strength of the magnet and the magnetisation of the ferrofluid, I've seen that this "collection" happens almost instantaneously. I'd like to find this picture a home in other articles (it's only in ferrofluid so far). Ignoring, perhaps, the fact that it is ferrofluid in oil, what principles are being illustrated here? I have some general ideas, but I'm sure there are some specifics that I'm completely missing, and my captions would probably be wrong, or at least too simplistic. Ideas? Thanks, :) Maedin\^talk 16:31, 13 November 2009 (UTC)

The interesting feature of the picture is the spontaneous formation of corrugations in the black ferrofluid above each end of the bar magnet where the magnetic field exceeds the critical strength for normal-field instability. I think other pictures the OP supplied[5] show this better. This picture shows some unexplained striations in the oil layer that look different at the two ends (poles) of the magnet. I guess these are effects of dispersed grains of magnetic material and surface tension of the oil. Cuddlyable3 (talk) 21:03, 13 November 2009 (UTC)

Yes, I was interested in the striations; I thought this must be a well-known physical property that I just wasn't familiar with. Thanks for your response. I'll try to get in contact with the author and see if he can enlighten any further. Maedin\^talk 17:22, 14 November 2009 (UTC)

On further thought, the ferrofluid may have been initially spread evenly on the surface which was then placed over the magnet. When the ferrofluid was pulled into the shape shown it left tracks of its movement in the oil film. Cuddlyable3 (talk) 18:09, 14 November 2009 (UTC)

Polyploidy in humans

Has any human survived Polyploidy into adulthood? If so, what happens normally? Is Polyploidy in humans considered a "bad" thing to happen? --Reticuli88 (talk) 19:07, 13 November 2009 (UTC)

Did you read our article on polyploidy, specifically the polyploidy in humans subsection? There's a wealth of information there, as well as a link to mixoploidy that notes adult humans with the condition. Whether polyploidy is "bad" depends on the standard you're using, though I don't think it's a difficult question to answer. — Lomn 19:19, 13 November 2009 (UTC)

It doesn't mention anything about adults. When I say bad, I mean is there something physically wrong with the adult who is afflicted with this or is it possible that one can become "super-human? --Reticuli88 (talk) 19:26, 13 November 2009 (UTC)

The condition is almost invariably fatal, and always results in sterility. Superheroes are just as likely to result from polyploidy as from ALS, synesthesia, or radioactive spider bites. — Lomn 19:43, 13 November 2009 (UTC)

Sense of impending doom

Wikipedia seems to have no article for this! It is a well known symptom in many cases, but I can't understand what on earth, biochemically, brings it about. Among other things, I hear blood transfusions (no source) can result in these, along with the classical myocardical infarction, from where I guess it is best known. Any help on this issue would really sate my curiousity; thanks in advance! =) 77.18.86.199 (talk) 19:35, 13 November 2009 (UTC)

Intravenous adenosine injection classically causes this sensation. Interestingly, lidocaine toxicity also causes this. Axl ¤ [Talk] 19:58, 13 November 2009 (UTC)

Anaphylaxis also causes a sense of impending doom (I can testify personally to this). I wonder if it's related to release of epinephrine. --NellieBly (talk) 10:17, 14 November 2009 (UTC)

Malaise tells us almost nothing. I feel one scrapes at the surface of something rather important here, but which is either left unstudied or is just so unpopular to study that the knowledge is not common. My googling efforts continue. 77.18.85.72 (talk) 15:58, 14 November 2009 (UTC)

Classically the rapid dropping blood oxygen from Pulmonary emboli gives a sense of impending doom. See dozens of references for this [6] --BozMo talk 21:10, 14 November 2009 (UTC)

The sensation described by the OP is defined as a foreboding n. a feeling of evil to come. Cuddlyable3 (talk) 12:19, 15 November 2009 (UTC)

EMP

Would an EMP kill humans? After all, we have electrical conductors in our body, yet in COD 6 the EMP detonated seemed harmless to humans. —Preceding unsigned comment added by 24.200.1.37 (talk) 19:52, 13 November 2009 (UTC)

We don't have anything in our bodies that would function as an antenna, so a EMP is harmless (unless you have a pacemaker, I suppose). --Tango (talk) 19:53, 13 November 2009 (UTC)

Electromagnetic weapon#Use against humans. It's not sourced, but it does list some possible side effects of electromagnetic weapons. Presumably how much our neurons were disturbed would depend on the strength of the pulse. It may also affect lymphocytes. ~ Amory (u • t • c) 20:07, 13 November 2009 (UTC)

As I have pointed out on the Science desk in numerous earlier EMP questions, "EMP" is very vaguely defined. In order to speculate about consequences, some parameters must be provided - the power, the duration, the frequencies, proximity to the source, etc. As it is, "electromagnetic pulse" is so vague a term, that the original question is impossible to answer. Every day, nontrivial electromagnetic pulses are emitted by mobile phones, radios, power stations, and other man-made and natural sources of electromagnetic energy. These EMPs are usually entirely harmless. There is a subset which are debated but might be harmful. Finally, at the extreme ends, very powerful doses of ionizing radiation have been shown beyond a reasonable doubt to harm humans. --Nimur (talk) 15:15, 14 November 2009 (UTC)

multiple ccd chips or cameras

If I and my friends (pretend I know Bill Gates and Warren Buffet) bought a lot of maximum megabit ccd cameras and wired their shutters to activate at the exact same moment and placed these cameras in stationary orbit (lets just say next to each other in the least light polluted and most stable place) and pointed each to the same infinite point in space then combined each image with software would this serve in the place of a parabolic mirror to intensify the image and thus allow it to be greatly magnified what magnification would be possible and would this be large enough to justify the project? 71.100.7.164 (talk) 20:04, 13 November 2009 (UTC)

Imaging in weak light of a CCD camera is limited by electrical noise generated on the CCD chip that shows as graininess in the resulting picture. If one can aim many chips at exactly the same object and combine their output signals (with no coding like JPEG in between) then the noise power can theoretically be halved with every doubling of the number of cameras. A practical objection to the scheme is the difficulty of aiming many cameras identically. Having many cameras does not provide greater magnification of the view. For greater magnification the cameras need longer-focus (telephoto) lenses which will make aiming even more critical. The area to be filled by camera bodies would be much larger than that occupied by the parabolic mirror they are supposed to replace. Cuddlyable3 (talk) 20:31, 13 November 2009 (UTC)

Actually what I am suggesting is that because you end up with a combined intensity of the same object which can be aligned exactly by software that because of the increased intensity you can perform the magnification by blowing up only a few number of ccd extremely high resolution cells which represent only a fraction of the object but are visible due to the greater intensity provided by all of the combined images performing the same function as a parabolic mirror. 71.100.7.164 (talk) 22:17, 13 November 2009 (UTC)

You may suggest that software can achieve perfect alignment but that does not make it easy. Enlarging or "blowing up" a CCD image always means reducing the number of cells per printed area. The number of cells on the CCD chip is fixed, as becomes obvious as blockiness (aliasing) when an image is greatly enlarged. If an object is larger than a point source then a few cells likely cover only a fraction of the object. It is unclear whether you are hoping to gain magnification in image size or image brightness. If the subject is stationary then there is no need to have a "lot" of cameras because one can use a single camera to take multiple pictures. A CCD camera coupled to a conventional reflecting or refracting telescope is a popular arrangement for astronomers and makes more sense than coaxing your famously rich friends to buy truckloads of cameras. Cuddlyable3 (talk) 17:59, 14 November 2009 (UTC)

For the sake of argument so as to eliminate the limitations of individual ccd pixels, although grains of silver still present this delimina, the reason for not taking multiple sequential images is to eliminate opportunity for temporal disparity. That said the way graininess is overcome using multiple cameras is by the very fact that they do not occupy the exact same location. The idea is that individual cameras can be designed to use a parabolic reflecting mirror in place of a lens to maximize magnification beyond the ability of the individual camera to distinguish a difference between light levels between adjacent cells due to the extreme magnification and then rely on multiple cameras to contribute to a measurable difference in intensity through image overlay for any wavelength of electromagnetic radiation. 71.100.7.164 (talk) 19:44, 14 November 2009 (UTC)

I believe the OP is referring to something more like an Astronomical interferometer, which is theoretically a quite powerful concept, provided you can get the components in place. Alfrodull (talk) 20:35, 13 November 2009 (UTC)

I would be surprised if the OP was thinking of interferometer because distance measurement is nowhere mentioned. Cuddlyable3 (talk) 17:59, 14 November 2009 (UTC)

You might look at MMT Observatory for a description of a similar idea (six cooperating telescopes) here on Earth. Looie496 (talk) 21:23, 13 November 2009 (UTC)

As our article mentions, there are various proposals for space based inferometers. For example Darwin (spacecraft) and Terrestrial Planet Finder and Space Interferometry Mission [7]. Then there's the rather extreme hypertelescope proposal from Antoine Émile Henry Labeyrie [8]. However these operate using multiple mirrors with one primary imaging sensor and not multiple sensors. And they all are likely to be rather expensive and require a very high degree of technology, in particular the ability to accurately position the multiple elements that we may not currently have. BTW, in terms of multiple mirror telescopes on earth, there are some other proposed ones e.g. check out Extremely large telescope, for example the Giant Magellan Telescope. There is also radical proposed stuff like a Fresnel Imager [9] although again only one camera. Nil Einne (talk) 16:20, 14 November 2009 (UTC)

Yes, mega multiple sensors with individual lenses, shutter and direction control i.e., cameras, is the system which I am suggesting. Has this ever been attempted and if not where can I submit a proposal that it be done? 71.100.7.164 (talk) 17:42, 14 November 2009 (UTC)

71.100.7.164 (talk) 05:53, 15 November 2009 (UTC)

You can send proposals for a new space-based research payload to NASA Ames Research Center or European Space Agency. Expect them to be reviewed by people who know fundamental optics such as diffraction limits, the 300-year history of refinement of the Optical telescope and the already established applications of CCD's in astronomy. You will be at a disadvantage if you cannot quantify your proposal in terms of this body of knowledge. Cuddlyable3 (talk) 12:15, 15 November 2009 (UTC)

has the lhc collided the particles yet

mid-november, we're almost in mid november but theres been nothing on it, this is one of the biggest scientific things to happen and yet theres no fanfare or anything.--Draw99990 (talk) 20:23, 13 November 2009 (UTC)

Both our article and the LHC website say that particles have circulated but not collided. DMacks (talk) 20:31, 13 November 2009 (UTC)

The article says "particles were circulating" as of October 30, but that's really an optimistic way of describing the situation, since particles aren't going all the way around. As of four days ago, they've got particles going half way around.[10] And the first high energy collisions aren't currently expected to occur until sometime in early 2010.[11] Red Act (talk) 20:43, 13 November 2009 (UTC)

You might already know this, but actually discovering new physics at the LHC will require careful analysis of months or years of collected data. There won't be a sudden jump in knowledge on the day the collisions start; there's no "moment of truth". -- BenRG (talk) 22:18, 13 November 2009 (UTC)

The Earth hasn't been swallowed by a black hole yet, so no. :-) StuRat (talk) 23:17, 13 November 2009 (UTC)

They got close - but then (believe it or not) a bird dropped half a loaf of french-bread onto the machinery - which overheated at that spot and shut the system down. So more delays... SteveBaker (talk) 23:17, 13 November 2009 (UTC)

How long does it take a bird to fly here from the future? --Trovatore (talk) 23:19, 13 November 2009 (UTC)

That depends. Is it African or European? —Akrabbim^talk 23:22, 13 November 2009 (UTC)

The LHC, like any other machine, is made of parts that sometimes malfunction and need to be fixed or replaced. This is a normal and anticipated part of the LHC's operation; it's not news. Furthermore, this story wasn't even true, according to this page at cern.ch. The mainstream media is worthless as a source of news about physics. Read physicists' blogs instead. Wikipedia is often good too. -- BenRG (talk) 02:27, 14 November 2009 (UTC)

Looking for Raccoon Penis

Now that I've caught your eye :) Seriously though, I'm preparing a presentation for class regarding raccoon anatomy, and my closer is going to be on this particular "bit". (Why? Keep reading!). I've got just about all of it covered regarding the baculum and so forth, but the thing I can't seem to find is a diagram or even a picture of how the baculum is connected, even which way is "up" on the thing, and how it appears when, errr.... in use, shall we say. All the anatomical diagrams and annotated skeletals I've found tend to omit this little feature. Online searches all return either a story about an unfortunate fellow who tried to get too friendly with a raccoon, or places to buy raccoon penis-bones which are apparently quite popular as trinkets in the Southern US. The latter is why I want to have this as my closer. I found a place that sells bags of the things, so I plan to hand them out to the class as both a visual aid, and as a sort of sociological experiment to see how they are received! :) So.... any ideas? Thanks in advance to all! —Preceding unsigned comment added by 75.227.198.51 (talk • contribs) 21:01, 13 November 2009

The article Baculum may help. You may criticize the speculation noted by Richard Dawkins that the loss of the bone in humans is the result of sexual selection by females. Your post is characterised by nervous euphemisms. A class of children will acquire such an attitude from their teacher. I'm almost certain this is a joke. Cuddlyable3 (talk) 21:45, 13 November 2009 (UTC)

Possible signs of global warming, or just common phenomena?

Hi. I'm in Southern Ontario, and recently this November I've noticed some possible signs of global warming. It is already mid-November, but some things are still occuring that one would expect in the warmer seasons. Just yesterday, I saw several dandelions, both the flowering kind and the white puffballs, as well as those in the closing stage. I also saw a flock of geese (or ducks) flying north in formation. Just today I saw around a hundred birds (either ducks or geese) resting in a small pond (although this isn't very unusual). Within the past week, I and other people in my community have seen ladybugs flying near our homes. Squirrels of different varieties are still commonly seen from day to day. Total precipitation so far this year has been the highest in the past six years, higher even than 2008, which produced a record-breaking summer rainfall and very high winter snowfall, despite having a dry spell in late August and early half of September of this year. We had a short period of warmth this November, being the second-highest recorded temperature in this period of November in the past six years (19C), second only to 2005, globally the warmest year on record. We have had only one minor snowfall this autumn of less than one centimetre, and in previous years snow has often fallen numerous times in late October to early November. Although I have noticed some of these signs in recent years, they appear to be becoming more common. Are any of my observations extremely unusual for my location and time, and could they be signs of global wrming? Thanks. ~AH1^(TCU) 21:47, 13 November 2009 (UTC)

The long-term changes to plant flowering times and to bird/insect migration patterns is certainly a very real, well-documented indication of climate change. They are subtly incidious because many animals and plants have carefully evolved their reproductive strategies around the timing and location of these kinds of event. So if a flower times it's peak nectar production by the average air temperature - but the bees that pollinate them time their spurt in worker-bee production by the length of the day - then the flowers may peak before the bees are ready to pollinate them - the flowers don't get their pollen spread around - and then when the bees do finally kick into high gear - the plants are already past their best. Both species suffer. Similar things happen with bird migration timed against insect hatchings. It's a delicate system that CAN evolve to meet change - but only so long as the change happens gradually and not at break-neck human-induced speeds.

In the flower/bee case, you'd probably just get another species of flower that flowers at a different time thriving at that latitude. We are actually getting that already. StuRat (talk) 23:11, 13 November 2009 (UTC)

The actual weather variations (ironically) are less convincing evidence. Weather is what's happening right now outside of your back door - and it's still sufficiently random to make it very hard to see whether there is a long-term trend. Climate is the average "weather" over large areas and large timescales - and the climate is what is steadily warming. The weather, locally can be unusually cold, unusually wet, unusually foggy...almost anything...because it's only the average that's climbing steadily. Here in central Texas, we've had a record number of insanely hot/dry days this year, leading to severe drought conditions - immediately followed by some of the heaviest rainfall on record...that's the hallmark of changing climate - that records (both highs and lows) tend to get broken more frequently because the weather gets steadily more chaotic. SteveBaker (talk) 22:42, 13 November 2009 (UTC)

OK, but what specifically about the dandelions in November (is this common or extremely rare at my location), and the presense of insects (just yesterday I saw housefly-like insects and what appeared to be a mosquito)? ~AH1^(TCU) 21:09, 14 November 2009 (UTC)

definition of 'oxychemical'

Google is failing me. I have seen the word 'oxychemical' twice today in peer-reviewed papers, but I can't find a definition. Here it is in context, "Fermentation microbiology with renewable resources ... has the potential to produce a large fraction of the oxychemicals and their derivatives that constitute the bulk of feedstock chemicals."

ike9898 (talk) 21:56, 13 November 2009 (UTC)

Oxy<blank> usually means <blank> with oxygen atoms as part of the molecules. See oxyacid, oxyanion, oxyfuel, etc. etc. This likely just means "compounds which contain oxygen". --Jayron32 23:41, 13 November 2009 (UTC)

You forgot Oxymoron Googlemeister (talk) 15:25, 16 November 2009 (UTC)

is anything reproduceable not part of science?

Is there anything reproduceable that isn't part of science? I mean, anything that isn't possible, so despite the fact that it can be shown and is reproduceable, is not acknowledged by science on the grounds of its impossibility. For example, was there a period of time when scientists did not acknowledge the flight of the bumblebee, as the understanding of aerodynamics at the time meant this was not possible? This is obviously just one example, a further example could be the Mpemba effect, specifically when the graduate students told their professor: The technician later reported that the hot water froze first, and said "But we'll keep on repeating the experiment until we get the right result", naturally tihs is a cue for the professor to say "that's okay, forget it", though luckily this did not happen. However, this example, like my first example, suffers from the fact that it is not contemporary. My question isn't whether there is anything reproduceable that wasn't part of science when it was first reproduceable; I'm asking if there is anythin reproduceable that isn't part of science now. So...anything? 85.181.147.202 (talk) 22:31, 13 November 2009 (UTC)

Not sure whether it answers your question but I don't think scientists ignore something just because they can't understand it. I don't think anyone ever refused to acknowledge the flight of a bumblebee. It's absurd to suggest that it's not actually flying, just because they haven't figured out the physics behind it. ----Seans Potato Business 22:59, 13 November 2009 (UTC)

The bumblebee thing is a myth. Science always accepts what can be measured and reproduced on demand under controlled conditions as "The Truth" - if the truth (such as that it's bloody obvious that bees can indeed fly) contradicts theory (that bees do not conform to the current theories of aerodynamics) - then we accept that the theory must need some adjustment. For example - just today there was a piece on www.slashdot.org talking about the Pioneer anomaly (a totally mysterious speedup of the Pioneer spacecraft as they left the solar system). The reason for this speedup is completely unknown and it appears to be breaking one or more scientific theories that we believe to be true. The phenomenon is only somewhat reproducible - some spacecraft have experienced it - others, seemingly, have not. ("While Galileo and NEAR had appreciable speed increases, Cassini and Messenger did not. Rosetta itself gained more speed than expected from its 2005 fly-by, but only the expected amount from its 2007 fly-by.") Until we figure out the cause (and there are plenty of hypotheses out there) - and do some more experiments, the best we can say is that we cannot currently explain the speedup. There could be several reasons for that:

• That one or more of our key theories (relativity, perhaps) is subtly incorrect. It would have to be a very, very subtle error though because these theories are extremely well tested.
• That there is some completely new phenomenon that we're unaware of (perhaps an undetectable source of gravitation outside of the solar system that's attracting these probes...but perhaps gremlins!)
• That there is some kind of error in the experimental data - which is why they're trying to use the Rosetta craft to do more precise measurements.
• That there is some enormous conspiracy to fake the Pioneer data...just like they faked the moon landings. (No, I don't believe that - but you can bet some conspiracy nut does).

I'm sure there are lots of things like that - that's how we end up with theories of Dark matter and Dark energy. Things we know are there because the experimental data says so - but for which we have no really good explanation yet.

You're kinda phrasing your question as if this somehow points to a horrible flaw in "Science" - when in fact, this is modern science's single greatest strength. In the last couple of hundred years, we've come up with a system for doing science that pretty much guarantees that we don't get into the kinds of horrible mess you describe with the Mpemba effect. Serious scientists most certainly DON'T keep doing an experiment until by chance it comes out the way we want. But more than that - scientists THRIVE on finding something that doesn't fit the present theories - that's the way we make progress. When every new fact fits perfectly into what we know - it's kinda satisfying that it's more evidence that we got it right - but nothing CLOSE to the joy of making a discovery that totally overturns some major theory. Everyone thinks Einstein was a genius and a hero for overturning Newton's laws of motion that had stood the test of time for hundreds of years. Einstein is considered to be one of the greatest humans ever to have lived because he found a serious problem with the status quo of science and overturned it. That's why everyone has gotten so excited over the Pioneer effect. It's an opportunity to refine what we know - and for some smart chap to make a name for himself.

SteveBaker (talk) 23:00, 13 November 2009 (UTC)

Sorry, thanks for the responses but I really did mean what I say: something reproduceable that science ignores on the grounds of its impossibility. Examples would be: any effect from a dilution (homeopathy) where the solution has been diluted so many times with distilled water that chances are there is not a single molecule of whatever you started with. Other examples would be telepathy, etc. By the way, I'm looking for an ACTUAL example, if anyone has one...instead you offered a scientific EXPLANATION for why such an example would not exist. Now the following sentence will blow your mind: if someone offers an example of something science ignores on the ground of its impossibility, will you accept this example despite your theory of its impossibility as outlined above, SteveBaker?  :) —Preceding unsigned comment added by 85.181.147.202 (talk) 23:32, 13 November 2009 (UTC)

Homeopathy is NOT reproducable. No controlled study has ever shown that homeopathic remedies produce any results above that of the placebo effect. Likewise, there have been dozens of controlled experiments on things like telepathy, which have turned up bubkis. The experiments on all of these things have been done. People are surprisingly willing to go through the trouble to do controlled experiments in these cases; which is good. Science shouldn't find any possibility off-limits, even though reasonable people would expect the negative result. Most of the time, the negative result is what happens anyways, but on a rare occasion, something interesting happens. --Jayron32 23:39, 13 November 2009 (UTC)

Other than homeopathy, can you think of anything that is reproduceable yet ignored by science? 85.181.147.202 (talk) 00:25, 14 November 2009 (UTC)

The success of the homeopathy is due to the placebo effect, selective memory, and clever marketing. All of which are well understood by modern science.

However, if you must have an example : Scientists have never adequately explained how Santa Claus delivers presents and/or coal to all the Christian children (and quite a few others) in a single 24 hour period. Yet it demonstrability happens every December between sundown on the 24th and sun-up on the 25th.

That's not to say that scientists always have a good an correct explanation for things, just look how long they thought light was carried by aether.

APL (talk) 04:21, 14 November 2009 (UTC)

That slashdot post you're quoting unfortunately confuses two different phenomena: The Pioneer anomaly is an unexplained slight additional acceleration of spacecraft in the direction of the sun, as the spacecraft head out of the solar system. The flyby anomaly is an unexpectedly large increase in the speed of a spacecraft during a gravitational slingshot maneuver. The reasons for the two kinds of anomaly may or may not turn out to be related, but the circumstances under which they occur are very different. But the main point of your post is valid, in that the existence of neither anomaly is being denied by scientists due to a current lack of a good explanation. Red Act (talk) 00:41, 14 November 2009 (UTC)

That is almost a contradiction in terms. To a very large extent checking whether something is reproducable is to engage in science. If you are saying homeopathy is reproducable you are in clear contradiction with the tests scientists have performed. Dmcq (talk) 00:34, 14 November 2009 (UTC)

No - by definition. 70.112.96.57 (talk) 00:36, 14 November 2009 (UTC)

And scientists haven't ignored Homeopathy - check out our article and you'll see any number of studies have looked for an effect and found NOTHING. So this is not a case of science ignoring something that's real - it's a case of a lot of charlatans trying to sell gullible consumers bottles of plain old water for prices that hover around $10,000 per gallon. Science has very carefully examined the claims - and they are not reproducible. Ditto telepathy, ditto all of that bogus stuff. Now you could claim that science turns it's back on what it doesn't understand - but that's demonstrably not the case - (case in point - the anomalous speeds of the Pioneer probes that I mentioned earlier). When the effect is real and can be reproduced under careful conditions - science treats it with respect and no small amount of excitement. When the effect isn't there - then it may be checked carefully and then safely ignored as bullshit...homeopathy being an excellent example of that. Cold Fusion is a good example of this. When some seemingly respectible scientists said they had this amazing effect - everyone got very excited about it. People tried hard to reproduce it - and when they couldn't - the whole thing dropped out of the realms of hard science and into the loving arms of the awaiting crackpots. The trouble is that the layman who does not understand the process sees cool idea after cool idea rejected by scientists. Perpetual motion would be cool - damn you scientists who showed that it's impossible! As science has gotten better and better at it's description of how the universe works - it's inevitable that the number of times we find an exciting and interesting anomaly gets smaller and smaller - and the excitement when we do gets bigger and bigger. In the 1800's an object moving a fraction of a percent faster than you expected was nothing to write home about. In 1900 - it would have been a curiosity worth remarking on - but nothing more. In 2000 - it's a major issue that we're about to invest a lot of time and money to track down and properly explain. Give it another 100 years and finding things that seem to outright fly in the face of existing theories is going to become very tough indeed. 70.112.96.57 (talk) 00:36, 14 November 2009 (UTC)

I can sort of think of an example, but I don't really think it counts. Way back when physicists were first discovering the concept of splitting an atom and atomic bombs, there was a big get-together. It was decided that the calculations made giving the mass needed to create a working bomb should be withheld due to the potentially dangerous uses. This didn't last long for a lot of reasons, least of all pride but especially since it became obvious that there were other, harder issues (the trigger, par exemple). Still, it was ignored so much as it was hushed for a little while. As the editors above say, if it's reproducible it's not ignored. It may not be widely studied at the moment, but those are issues more related to funding and interest. ~ Amory (u • t • c) 00:45, 14 November 2009 (UTC)

The failure of any party to claim James Randi's prize goes a long way to dispelling the notion that science might behave in such a way. -Craig Pemberton 02:24, 14 November 2009 (UTC)

Fun fact : The bumblebee thing is a myth. The boring truth is that one scientist made an error in a back-of-the-napkin calculation during a dinner party. His biologist collieges spread the story far and wide, because if there's one thing biologists love is to prove that they're smarter than those smug jerks from the physics department.

The "Fact" that bumblebee's can fly was never based on accepted actual, current, scientific thought. APL (talk) 04:11, 14 November 2009 (UTC)

In terms of the Mpemba effect, while I've read multiple conflicting claims about precisely what happens it's my understanding that the issue is that it was something that few scientists had studied or were aware of at the time and while it was known by some lay people, it's apparent that many people were not aware of it. No one demonstrated it to any scientist and since it seemed unlikely, many dismissed it when people claimed it was the case. I'm sure many scientists get people making claims which are made up, delusions or simply the result of poor methodology so it's hardly surprising that many scientists will dismiss such claims off hand without any evidence. However I'm not even aware any scientist did dismiss the claims, Mpemba was a secondary school student and he told his teacher who did dismiss it (and possibly made fun of him as a result of that) and while the teachers actions are perhaps not uncommon although also perhaps not a good thing, I'm doubtful that the teacher would fit most definitions of a 'scientist'. The first scientist who he did tell (that we're aware of) did not in fact dismiss the claim and instead asked a graduate student or technician to test it. Whatever the student/technician really said (and I suspect it's unlikely we'll ever really know) the basic idea was sound, an extraordinary claim requires extraordinary proof so many repetitions were necessary before they took it any further. Had anyone publicly demonstrated the Mpemba effect it wouldn't surprise me if it would have attracted more interest and similarly someone who would not normally be considered scientist could likely have published a paper on it if they went about it the right way and put a bit of effort into it. In other words, it's not something that scientists didn't accept rather that they simple weren't aware of and wouldn't likely not have accepted without good evidence since it didn't fit with theory Nil Einne (talk) 09:19, 14 November 2009 (UTC)

You may wish to consider the work of Rupert Sheldrake, in particular "The Sense of Being Stared At", as part of the answer to this question. --TammyMoet (talk) 15:20, 14 November 2009 (UTC)

What type of soda?

Hello desk. I am trying to make ink using a method found in some ancient Nepalese scrolls. The translation says at one point: "If one puts soda in boiling tea, this melt is said to be the best binder for ink." I finally found out what the glue liquid it keeps referring to is made up, but I don't know what type of soda the scroll refers to. According to the soda disambiguation page, it could be sodium oxide, sodium hydroxide, sodium carbonate, or sodium bicarbonate. I also see that sodium hydroxide is used in the bleaching of wood pulp. Since we're making (black) ink from fungal spores, perhaps this means it is not sodium hydroxide, or lye? I believe in another portion of the scroll it states that the same solution will congeal when it cools. What soda do you think it could be? Also, is the tea important, or do you think boiling water would be chemically sufficient? Thank you for any help! Mac Davis (talk) 22:37, 13 November 2009 (UTC)

If the solution "congeals" - then one needs to know how strong it is. Sodium Carbonate (the "normal" use of the name soda these-days) will form a decahydate - so 105g of sodium carbonate combines with 181g of water - this will melt at just 34°C - so one would not see any solid until the solution was below that temperature - so say 1 part sodium carbonate with 2 parts water will almost set solid at ambient. Sodium hydroxide is very soluble - 100g in 100g of water would be a solution which would start to crystallize at room temperature. Sodium bicarbonate is not very soluble, it will start to crystallize at ambient about 8% strength - but just throws down a white solid. My best guess is Sodium carbonate.  Ronhjones  ^(Talk) 23:02, 13 November 2009 (UTC)

Actually I think the "normal" use of the word soda is as shorthand for soda pop. Depends on where you live, of course. Somewhere you can find a map of the US and Canada, divided by where they say soda and where pop. --Trovatore (talk) 02:21, 14 November 2009 (UTC)

And they are "fizzy drinks" over here. Much more logical, we Brits are...  Ronhjones  ^(Talk) 18:41, 14 November 2009 (UTC)

Say what? I ordered a lemonade over there, and they brought me some nasty Sprite or something. --Trovatore (talk) 20:09, 14 November 2009 (UTC)

That sounds perfect Ronhjones! According to the article it is used as a bonding agent in alginate and can be easily extracted from the ashes of any plant. Mac Davis (talk) 00:31, 14 November 2009 (UTC)

That makes it even more interesting... See Potash - Plant ash would be initially potassium hydroxide, but that would rapidly absorb carbon dioxide (on cooling) to make potassium carbonate. So if the main source is plant ash then I'll plump for potassium carbonate (but there's a good chance sodium carbonate should work just as well in your application).  Ronhjones  ^(Talk) 18:38, 14 November 2009 (UTC)

Two girls, one baby (or two guys, one baby) - artificially fertilising an ovum using two ova nuclei or to sperm nuclei

Am I correct in thinking that parental imprinting would prevent the development of ova (with their original nuclei removed) fertilised with nuclei from two sperm or with the nucleus from other ovas? I expect that certain required genes would not be expressed in the correct ratios because the patterns would be the same in both sources and therefore not complementary? ----Seans Potato Business 22:52, 13 November 2009 (UTC)

Yup. I gave a pretty complete answer to this same question half a year ago: Wikipedia:Reference_desk/Archives/Science/2009_February_12#Same-sex_gametes_combining_to_form_a_zygote.3F. Someguy1221 (talk) 23:12, 13 November 2009 (UTC)

The Genomic imprinting article also describes experiments with mice to this effect. Rckrone (talk) 23:25, 13 November 2009 (UTC)

What would happen...

What would happen if less than half of the universe was nothingness? jc iindyysgvxc (my contributions) 23:05, 13 November 2009 (UTC)

It was, for part of its history. See Timeline of the Big Bang and the subarticles on the specific "epoch's" during the first few seconds. --Jayron32 23:32, 13 November 2009 (UTC)

It would rapidly collapse in a Big Crunch. That said, I don't think it is possible for the universe to reach its current size and age with that kind of density (in fact, it may not be possible for it to have that kind of density anyway - one of the results of inflationary theory is that the density of the universe will inevitably end up close to the critical density, and that theory seems to be well supported by evidence). --Tango (talk) 02:55, 14 November 2009 (UTC)

Which half? The left half or the right half? :) For some people with brain injury, see Hemispatial neglect, one side of the universe to all intents and purposes disappears and they don't seem to notice much. 12:09, 14 November 2009 (UTC)