Science desk
< January 1	<< Dec \| January \| Feb >>	January 3 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

January 2

Carbon group

In the French Wikipedia, there is given an alternative name for the carbon group: Cristallogène (which would probably be "cristallogens" in English). What is the etymology of this name and why isn't it used in English (I've never seen the term in English)? Double sharp (talk) 02:46, 2 January 2012 (UTC)[reply]

It looks like it means "crystal generating". While carbon and silicon readily form crystals, you don't normally think of metals like tin and lead being crystal generating elements (although they might under some conditions, I suppose). Conversely, many other elements not in that group also form crystals readily, so it seems like a questionable name, to me. StuRat (talk) 03:31, 2 January 2012 (UTC)[reply]

You mean like lead crystal? --Jayron32 04:19, 2 January 2012 (UTC)[reply]

That's not made from just lead, but only a small potion of lead added in. StuRat (talk) 06:17, 2 January 2012 (UTC)[reply]

But pnictogen also doesn't fit very well as a name as metals like bismuth aren't really choking. Double sharp (talk) 14:06, 2 January 2012 (UTC)[reply]

And, you'll note, that lead crystal is mostly silicon, which is in the Carbon group. --Jayron32 21:26, 2 January 2012 (UTC)[reply]

John Daniel Titius and John Elert Bode

happy new year

what is the real reason of Titius -Bode low? --Akbarmohammadzade (talk) 04:05, 2 January 2012 (UTC)[reply]

It was an attempt to calculating the orbits of the planets in a predictive manner. It seemed to correctly predict the asteroid belt and uranus, but completely missed Neptune. IIRC, given a 66.7% success rate over a small sample size, it may have been just dumb luck that it gets right what it did. --Jayron32 04:17, 2 January 2012 (UTC)[reply]

can we generalize it to dynamic of galaxies?(the main mass separates its sub system automatically in such rule?--Akbarmohammadzade (talk) 04:33, 2 January 2012 (UTC)[reply]

The article is Titius-Bode law. The article does have some theoretical explanations - possibly, the way planets form (collapsing disk of matter) can lead to certain regular powers of distance of planet formation, with orbital resonance perhaps increasing the probability of such spacing. By fitting several planets (Mercury, Venus, Mars, Jupiter, and Saturn), some sort of regular pattern was created for the solar system, which two more planets also happened to fit (and Neptune didn't). Note too that, according to the currently most accepted theory on the formation of the solar system, the Nice model, the Uranus and Neptune were formed closer to the Sun, and migrated outward. The Nice model is still very new, and by no means universally accepted. It was later pointed out that some of the large moons of Jupiter and Saturn also followed regular, though non-Bode distance patterns. This expanded model is termed Dermott's law. Is there really some effects that conspire to give Bode-like planet distances, or is it just dumb luck? Maybe if we can start mapping solar systems of other stars, it will become more clear. Buddy431 (talk) 04:50, 2 January 2012 (UTC)[reply]

We have started mapping solar systems of other stars. We know of 6 planets around Gliese 581 for instance. I'm not sure if they follow any kind of Titus-Bode style law or not, though. --Tango (talk) 13:27, 2 January 2012 (UTC)[reply]

What is the specific gravity of quartz sand?

Resolved

– – Kerαunoςcopia^◁_galaxies 05:43, 2 January 2012 (UTC)[reply]

...in ~~lbs/square-ft~~ lbs/cubed-ft? A family member needs to know this and I have absolutely no idea how to go about finding this (less a Google search, which didn't turn up any immediate answers). The specific gravity article sort of intimidates me, especially the part about temperature and pressure needing to be specified for "both the sample and the reference". This is beyond me, but apparently someone thinks I'm a genius at science. Should've kept my mouth shut during Christmas dinner! Any help would be great, thanks so much! – Kerαunoςcopia^◁_galaxies 04:05, 2 January 2012 (UTC)[reply]

As sand consists of particles, the specific gravity might vary by the coarseness/fineness of the particles, but I'm not sure whether the more coarse or the more fine sand would have the greater specific gravity. Bus stop (talk) 04:24, 2 January 2012 (UTC)[reply]

Your units aren't right either. True specific gravity is a unitless number. Sometimes when people say specific gravity, they really mean density, but even there, your units aren't right (should be mass per volume. You have weight per area. You might charitably assume they mean pound (mass), but you still need a per volume, rather than per area). What's the context that you need this for? Buddy431 (talk) 04:33, 2 January 2012 (UTC)[reply]

Yes - lbs/cubic ft would make more sense. Actually, following on from Bus Stop, I think that the shape of the particles will matter more - as will the variation in size. The density of 'sand' will necessarily be less than that of the bulk material it is made up of - quartz rock in this case. As for how much less, this will depend on how efficiently it packs together. You'll also need to specify whether you mean dry sand or wet - wet sand can hold a lot of water. AndyTheGrump (talk) 04:41, 2 January 2012 (UTC)[reply]

(edit conflict)Specific gravity is a unitless ratio between the density of the comparing substance to a reference substance (usualy water,) as in how many times heavier is substance A than water at some temperature and pressure. Quartz sand should ideally be composed of crushed quartz; the specific gravity is 2.65 from the quartz article. However, it could be different due to impurities. Plasmic Physics (talk) 04:57, 2 January 2012 (UTC)[reply]

If you want to include the voids between grains, then a simple experiment would be to simply measure the volume taken up by a pound of water, and a pound of quartz sand, and divide the first value by second. Plasmic Physics (talk) 05:05, 2 January 2012 (UTC)[reply]

A Google search on [density sand] yields tables with a wide range of values -- all the way from 90 lb/ft³ to 100 lb/ft³ for dry loose sand up to 120 lb/ft³ to 130 lb/ft³ for wet packed sand. If you truly want an answer in lbs/square-ft, then you are seeking the areal density, and you need to multiply by the desired thickness. For instance, a four inch layer of damp packed sand with a density of 120 lb/ft³ has an areal density of 40 lb/ft². If you are seeking precise numbers, you will need to provide more information in your question. -- ToE 05:38, 2 January 2012 (UTC)[reply]

(E.C.) Also note that many of the density tables you find online give metric values, and while you can convert directly, an understanding of specific gravity can help you do it in your head. Unless you are interested in a great deal of precision, don't worry about the finer details in our article which threw you off; just think of specific gravity as the ratio of density of the substance in question to the density of water. Thus if a table states that wet, packed sand has a specific gravity of 2.082, then you know that it is 2.082 times more dense than water. The density of water is about 62.4 lb/ft³, so just multiply to find that the density of wet, packed sand is 130 lb/ft³ . Many of the tables you will find will give densities in metric units, but don't despair, as you can read the specific gravity directly from such figures. This is because the metric system was set up so that the density of water is 1 g/cm³, which is the same as 1 g/ml, or 1000 kg/m³, or 1 metric ton per cubic meter. Thus, when you see a table which gives the density of wet, packed sand as being "2082 kg/cu.m", you know that is 2.082 times as dense as water, and is thus the same as 130 lb/ft³. Does that help? -- ToE 06:02, 2 January 2012 (UTC)[reply]

Oops, I meant cubed-feet (fixed). I knew there'd be more to this than meets the eye! : ) I will pass on the information. Thanks so much for everyone's help! Sorry for the error again. – Kerαunoςcopia^◁_galaxies 05:43, 2 January 2012 (UTC)[reply]

I just reinserted the original "lbs/square-ft" into your question, but ~~struck out~~, so that future readers of the archives will understand why some of the answers were discussing units the way they were. Hope you don't mind. -- ToE 06:09, 2 January 2012 (UTC) [reply]

health education

what is health education? — Preceding unsigned comment added by 85.15.40.77 (talk) 07:24, 2 January 2012 (UTC)[reply]

Just what it sounds like, education about human health. Some basic biology is usually included, including sex education. These days, more emphasis on a proper diet and exercise might also be included, in the hopes of fighting obesity. StuRat (talk) 07:27, 2 January 2012 (UTC)[reply]

We have an article with just that name - Health education. It should help. HiLo48 (talk) 07:29, 2 January 2012 (UTC)[reply]

Mammoth

How long will it be before somebody seeks to make one inside an elephant? Kittybrewster ☎ 16:51, 2 January 2012 (UTC)[reply]

Who says they aren't already trying [1] :) IRWolfie- (talk) 16:55, 2 January 2012 (UTC)[reply]

The Pleistocene Park effort is related to that (I think it's the same people). -- Finlay McWalterჷTalk 21:09, 2 January 2012 (UTC)[reply]

Yep, it's a joint effort by Russian and Japanese scientists. ETA is 5 years.-- Obsidi♠n Soul 21:17, 2 January 2012 (UTC)[reply]

Very helpful. Let's hope they make two, 1f 1m. Kittybrewster ☎ 02:56, 3 January 2012 (UTC)[reply]

Once they start mass-producing them, can we expect McDonald's to introduce the Mammothburger? ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:54, 3 January 2012 (UTC)[reply]

If it's anything like the McRib, it needn't have come from the inside of a Mammoth anymore than the McRib has been anywhere near the ribs of a pig... --Jayron32 05:08, 3 January 2012 (UTC)[reply]

Man, if the McRib isn't actual pork it blows this article out of the water, which would be a shame. Meelar (talk) 08:14, 3 January 2012 (UTC)[reply]

According to that article (which is a fascinating read), the McRib is from pork shoulder, which is at least in the neighborhood of the ribs. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:08, 3 January 2012 (UTC)[reply]

People have been known to eat the original, once they defrost them [2]. 75.41.110.200 (talk) 16:46, 3 January 2012 (UTC)[reply]

Cloned mammoth would have the advantage of being a tad fresher. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:55, 3 January 2012 (UTC)[reply]

According to the list of ingredients there are roughly 70 ingredients. The meat is made of pig innards and lots of salt. Typically, "restructured meat product" includes pig bits like tripe, heart, and scalded stomach. Bon appetite, Von Restorff (talk) 14:46, 4 January 2012 (UTC)[reply]

Bugs: read Isaac Asimov's short story A Statue For Father some day. – b_jonas 09:59, 5 January 2012 (UTC) [reply]

Higher derivatives of displacement w.r.t. time

The Wikipedia article on displacement lists several names for some higher derivatives of displacement w.r.t. time: snap, crackle, pop, lock, and drop (together with their synonyms). I've never seen these names before but I hesitate to declare them unestablished. Does anyone know how standard these terms are, and whether they meet Wikipedia's criteria for inclusion in the article? — Preceding unsigned comment added by 173.49.10.51 (talk) 20:30, 2 January 2012 (UTC)[reply]

Unhelpfully, that information claimed to referenced to wearcam.org, which is (really really obviously) an old mirror of Wikipedia itself, and thus isn't a reliable source. -- Finlay McWalterჷTalk 20:46, 2 January 2012 (UTC)[reply]

Jounce does cite a source for a couple of them, but the citation calls their use "facetiously" -- Finlay McWalterჷTalk 20:48, 2 January 2012 (UTC)[reply]

This article states, "Another less serious suggestion is snap (symbol s), crackle (symbol c) and pop (symbol p) for the 4th, 5th and 6th derivatives respectively. Higher derivatives do not yet have names because they do not come up very often." Based on this, I'd be inclined to just replace the 4th-6th equations with a sentence to that effect and drop the higher ones entirely. Clarityfiend (talk) 20:55, 2 January 2012 (UTC)[reply]

Searching Google for that phrase "In the UK jolt has sometimes been used instead of jerk" finds it used in all kinds of places; it's not clear what the real source is, and for us to give it credence as a ref we'd need to know who originally wrote it, and whether they're a reliable source. That specific page says it comes from someone called "Philip Gibbs", but who is that? It's on John Baez' website, which is a good sign, but it's not from Baez himself, so it's not a reliable source yet. -- Finlay McWalterჷTalk 21:06, 2 January 2012 (UTC)[reply]

Google scholar finds hits for 'jounce acceleration', and from memory, I think an Open university programme referred to 'joggle and jounce' in regard to fairground ride designs. AndyTheGrump (talk) 20:58, 2 January 2012 (UTC)[reply]

More - A Google Scolar search for 'jounce fairground' [3] finds an Oxford Journals article [4] that apparently contains the following: "Students can use a computer algebra system, such as Maple, to experiment with different fairground designs, eg to determine the jerk and jounce (third and fourth derivatives) of a track or find any track with a specified jerk and jounce...". I've not got access to the paper, but it looks convincing. AndyTheGrump (talk) 21:39, 2 January 2012 (UTC)[reply]

Wikipedia is not an indiscriminate list of any term anybody ever used to describe anything. Those names are uncommon. I have removed them from the article, and replaced the section with a discussion, including cited sources. Nimur (talk) 21:48, 2 January 2012 (UTC)[reply]

Thanks, that's an improvement. The names read like an advert for Rice Krispies! We might as well call them Piff! Paff! Puff! (see Swedish product) Dbfirs 00:10, 3 January 2012 (UTC)[reply]

immunolin

Know anything about "Immunolin"? It's a product that's supposed to help boost the immune system. It's about the immunoglobulins IgA IgG Igm. — Preceding unsigned comment added by 96.38.177.108 (talk) 22:40, 2 January 2012 (UTC)[reply]

I merged your duplicate question, keeping the more detailed second edition of it.

[5] is the company's official word on it. They call it a "nutritional supplement", which means they do not have to follow the FDA standards for drug testing or effectiveness. The product needs to be reasonably safe and non-harmful, which is what they claim, not necessarily to have any specific proven benefit (which they do not claim)--they say it is a "bovine globulin concentrate".[6] We do have articles about immunoglobulins. I wouldn't expect them to be orally available. DMacks (talk) 22:49, 2 January 2012 (UTC)[reply]

(edit conflict - DMacks has already said exactly the same thing, but I've typed it now so I'll post it!) You can get the official story at their website: http://www.immunolin.com/about-immunolin.aspx (basically it's just a load of antibodies). Their FAQ says it comes from the blood of cows. It would appear that it has no scientific backing, though - the bottle in the photo on the front page has "dietary supplement" on it, which is code for "has never been proven to have any clinical benefit whatsoever". --Tango (talk) 23:08, 2 January 2012 (UTC)[reply]

This is an interesting concept, but the information is too scanty for me to reach a firm conclusion. The first issue is that the various components are supplied as "capsules, tablets, or powders", which makes me doubt whether they are formulated with enough protection to reach the intestine intact. (Though simply protecting the oral area might arguably have some effect) See passive immunity for more information about ingesting antibodies. The second issue is, would the effect of these antibacterial components be positive or negative? Gut flora is natural and often beneficial; we rely for example on Oxalobacter to remove oxalic acid from foods like strawberries to keep us from getting kidney stones. These bovine blood antibodies don't sound specifically targeted in any way against harmful bacteria - though I'd be intrigued to see what happened if you immunized each cow with a whopping dose of killed Streptococcus mutans a few months before harvesting; would the supplement interfere with tooth decay? There's also the issue of what happens to the stuff - for example, if they did specially coat the bovine antibodies to get them past stomach acid to the gut intact, could some manage to sneak into the adult circulation? Could that cause trouble? (Do babies fed cow's milk get any harmful effects along the line of serum sickness from foreign antibodies in their circulation?) If the transferrin remains active and lowers iron levels in the gut lumen, does that lead to iron deficiency in the person taking the supplement? Then there are the "growth factors", including IGF-1, which is not very stable in adult intestine [7] but also probably others - if these reach the intestine intact, I would be very cautious about whether they increase tumor risk. Again, the effect in the mouth might be significant - does that mean faster healing of cold sores or a higher rate of oral cancer? In general this concept seems on the verge of being clever enough to potentially be beneficial - which means it's also on the verge of being potentially dangerous. But my suspicion is that they're just pouring a BSA byproduct into basic caplets and not actually isolating all these different things at high dosage/purity, nor formulating them to survive stomach acid, so it's just a refined method of eating blood. Wnt (talk) 09:47, 4 January 2012 (UTC)[reply]

Animal intelligence

Other than humans, which animals are the most intelligent? --108.225.115.211 (talk) 23:17, 2 January 2012 (UTC)[reply]

Animal cognition is a good place to start. My understanding are that animals that are agreed to be most intelligent beyond human are things like Dolphins, Chimps, Dogs, Pigs and Crows too. One test of self-awareness is the Mirror test, apparently an indicator of intelligence in some way. 23:26, 2 January 2012 (UTC)

See also the encephalization quotient, which gives a nice rough measure of gross brain potential across species. (It would add elephant to the above list, which is probably right.) Of course, it's worth remembering that in general, animals are specialists. There are some tasks of "intelligence" that many of them can do that far outclass humans (squirrels can remember the locations of thousands of hidden nuts, despite having a very tiny and otherwise unimpressive brain). It is not clear that there is anything like general intelligence even within the human species, much less across species. I'm a big fan of Temple Grandin's Animals in Translation as a nice way to think about the similarities and differences between the human mind and the minds of other animals; she makes the point, again and again, that thinking of animals and neurotypical humans as thinking in the same way (but with animals on a shallower end of the pool) is probably not a very correct model. --Mr.98 (talk) 00:13, 3 January 2012 (UTC)[reply]

The octopus is alleged to display problem-solving intelligence. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:03, 3 January 2012 (UTC)[reply]

And an uncanny ability to see into the future apparently. ;) --jjron (talk) 11:44, 3 January 2012 (UTC)[reply]

I see there was some controversy over whether "Paul" was one or two octopi. However, note the quote that octopi "are the most intelligent of all the invertebrates." That puts them head and shoulders, so to speak, above the average clam or jellyfish. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:01, 3 January 2012 (UTC)[reply]

Though ranking higher than a jellyfish is not much to be proud of, given that they lack brains altogether. (Cuttlefish are also known to be quite intelligent.) --Mr.98 (talk) 17:52, 3 January 2012 (UTC)[reply]

In fact, octopuses (and other cephalopods) are sometimes considered Honorary Vertebrates, meaning you have to use anesthesia when you operate on them, and other such things. Now there are a lot of vertebrates that most people don't consider particularly intelligent, but for an invertebrate, cephalopods are extremely advanced in the brain department. Buddy431 (talk) 00:27, 4 January 2012 (UTC)[reply]

They do surgery on octopuses? ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:36, 4 January 2012 (UTC)[reply]

Of course! How else could they discover the fact their arms have minds of their own?

To find out if octopus arms have minds of their own, the researchers cut off the nerves in an octopus arm from the other nerves in its body, including the brain. They then tickled and stimulated the skin on the arm. The arm behaved in an identical fashion to what it would in a healthy octopus. The implication is that the brain only has to send a single move command to the arm, and the arm will do the rest. The neuroanatomy of octopi is a bit mysterious. The octopus is very intelligent. Scientific experiments have proven they can learn and possess both long-term and short-term memory. Octopuses can negotiate mazes, solve puzzles, distinguish between shapes and patterns and imitate observed behavior. They are notoriously clever at escaping containment and fishermen have found octopuses breaking into the crab holds of their boats to get a meal. In deference to their intelligence, some countries require the octopus be anesthetized before scientists can conduct surgery on them. In the United Kingdom the octopus has been given honorary vertebrate status, extending to this eight-legged cephalopod the same protections against cruelty and neglect that have been extended to other animals. Here you can see a cephalopod doing an IQ-test. They are able to open jars and turn the light off. They are able to use tools to build houses. To make a long story short: cephalopods are more interesting and much more intelligent than some humans. Von Restorff (talk) 13:21, 4 January 2012 (UTC)[reply]

Octopi opening jars or entering flasks to get at crabs don't really impress me - I think this is a simple application of their natural methods of food gathering. Fiddling around with an unknown object until something happens is not really a matter of intelligence but just responding to a sensation of yielding - it implies proprioception, yes, but not brilliance. But the octopus turning the light off with a jet of water very much impresses me, because it seems like a plan to climb the tank, to remember where to shoot the water, and to somehow imagine that it can change the light level, something which it cannot do in nature. It is hard not to think that the octopus actually hates the light, and the ability to hate, to be dissatisfied and imagine a change is possible, to me, seems the defining quality of human intelligence. I wonder if there is confirmatory data available about this type of behavior. Wnt (talk) 17:26, 4 January 2012 (UTC)[reply]

You just precisely described how I edit Wikipedia... Shadowjams (talk) 11:31, 6 January 2012 (UTC)[reply]

Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn-- Obsidi♠n Soul 11:48, 6 January 2012 (UTC)[reply]