Wikipedia:Reference desk/Archives/Science/2008 November 19

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November 19

Heroes

In what ways is the science in the show Heroes (for instance, the way they discuss evolution or utilize the genome project) bad? And I'm not just talking typical super-power suspension of disbelief here: I mean, when they try to use real science on the show, how often are they on/off the mark? --64.26.98.90 (talk) 00:22, 19 November 2008 (UTC)

There's a lot of online discussion about this, e.g. [1] [2]. You could check out Heroes forums/boards, e.g. the IMDb[3]. —Preceding unsigned comment added by Maltelauridsbrigge (talk • contribs) 12:22, 19 November 2008 (UTC)

The "real science" on Heroes is almost entirely science fiction. There is no resemblance between our current understanding of the mechanisms of evolution and what the dear Dr. Suresh loves to pontificate on. While it is true that the genome projects have given us huge insights into many areas of biology, there is no reality to the science of Heroes. Don't let it stop you from suspending your disbelief, though. I love the show, even if the pseudoscience is sometimes a bit appalling. By the way, this probably applies to almost all pop TV shows that involve some form of "science" or "medicine" in their plot lines. Most of them are vast distortions of the real world. Medical geneticist (talk) 15:32, 19 November 2008 (UTC)

One of the ways I suspend disbelief when watching this brilliant show is that since their fictional powers emanate from their brains, perhaps they are able to produce quantum effects on a massive scale by altering probability using unusual neural processes, even to the point of overcoming conservation of energy (definitely required if you are going to fly into space) but in the far future transhuman technology based on a new unknown physics could make such powers commonplace. The probability of such powers developing naturally is a bit far fetched because if genetics did have the potential for this, every living creature would have evolved to exploit such an enormous advantage. The way I suspend disbelief on this issue is that nature only does just enough to get us to feed, reproduce and avoid predators, and has no use for us after we have served this function-hence we do not regenerate badly damaged organs and limbs or have eternal youth. Of course a new plot line has some of the heroes altered by genetic scientists which is a bit more plausible, albeit a hundred years from now. In real life evolution, what was to other creatures was a monstrous superpower has evolved twice. Sight in prehistoric times and later, human intelligence. There were very large gaps between the two so who is to rule out the next step in evolution, but the biggest likelihood is that it will be created by human science rather than genetics. Another method to suspend disbelief on the issue of why such powers would not have develped earlier or be widespread is that perhaps the solution space had so many bridges and false maxima and minima that even the power of evolution could hardly ever reach such perfection. Of course the Superman films simply get round that by saying he comes from a part of the universe with an entirely different physics-in which case he would havecome from a parallel universe. And as for conservation of energy, apparantly he is fueled by solar neutrinos which somehow interact with his dense matter. —Preceding unsigned comment added by 80.0.106.90 (talk) 03:22, 20 November 2008 (UTC)Trevor Loughlin (talk) 02:36, 23 November 2008 (UTC) 80.0.106.90 (talk) 03:27, 20 November 2008 (UTC)

My main complaint about the "science" in Heroes is when they refer to the Human Genome Project. In reality only a handful of individuals contributed their DNA to the project(s), but in the show they treat it like a database of the genomes of every human being on the planet. Aaadddaaammm (talk) 18:59, 20 November 2008 (UTC)

OK, and the idea that a simple mutation can cause such fricking cool (and diverse) phenotypes is ridiculous. And also genetics (Darwin even got this right) does not allow major, disruptive mutations to effect a population, the only way evolution occurs is by TINY, stepwise changes. Aaadddaaammm (talk) 19:03, 20 November 2008 (UTC)

Me again, I just read the first link supplied up there ^, and it says exactly what I said (just more eloquently). Go science! Aaadddaaammm (talk) 19:12, 20 November 2008 (UTC)

Plasma

How would moving through Plasma feel aside from it burning/hurting you?--76.28.73.16 (talk) 00:59, 19 November 2008 (UTC)

Obviously, that depends a great deal on the plasma temperature (or, in general, electron energy distribution), density, and composition :) . In a very cold and dilute interstellar plasma you would freeze to death rather than burn (unless suffocation or very rapid loss of fluids kills you first, of course). In a rather hot plasma (and radiation field) of a stellar atmosphere you would evaporate rather fast. However, in a weakly-ionized air at sea level you will probably last very much longer. St. Elmo's fire plasma is harmless, unless you get struck by lightning eventually. --Dr Dima (talk) 02:16, 19 November 2008 (UTC)

Ahem... Space Does Not Work That Way. If the plasma is dilute, you would explode way before you would freeze to death because there aren't enough plasma particles coming into contact with you to transfer heat away from your body. « Aaron Rotenberg « Talk « 04:34, 19 November 2008 (UTC)

AhemHEM... You wouldn't explode; your body is far too resiliant. If you're mouth were open, the air would merely be rapidly sucked out of your lungs (or if not, likely, through your nose). If you closed your eyes, mouth, and plugged your nose, your body would probably "spring a leak" somewhere, but once your lungs were emptied of their contents (which wouldn't take too long) the integrity of the rest of your corpse would be quite fine. After a time, the moisture in your body would likely evaporate, leaving a nice, dessicated mummy floating around in orbit. Sleep well! --Jayron32.talk.contribs 04:43, 19 November 2008 (UTC)

The release of some of those would be fairly abrupt (especially if you had your mouth open), so it could still sort of be described as an explosion, or perhaps a series of explosions. And it's definitely not freezing. « Aaron Rotenberg « Talk « 00:37, 20 November 2008 (UTC)

Parts of your body may rupture (i.e. tear through) but you will definately NOT "explode" in the sense that you won't spray little bits of yourself all through outer space. You will likely not escape injury in the event of exposure to a hard vacuum, but your body will be intact. Look, there's just not enough pressure in your lungs to do any damage to your trunk. At earth-pressures, you can expect about 760 torr (15 pounds per square inch, or 1 atmosphere) of pressure in your lungs. Your body can and does survive those pressures quite easily. Think about scuba divers. They can go down to well over 2 atms of pressure without their bodies crushing in on themselves. The pressure in your lungs cannot exceed 1 atm of pressure pusing out; your ribcage and the rest of your chest is quite able to withstand such pressures without any trouble. Now, the air will likely cause ruptures in particularly weak places as it escapes (sinuses, ear drums) but there's just not enough force inside your lungs to make your body spray little bits everywhere. But we are in agreement that you certainly won't ice up. As I said, you'll mummify long before your temperature drops enough to freeze. --Jayron32.talk.contribs 02:24, 20 November 2008 (UTC)

Very well. It's just as disgusting (and probably more disturbing) that way. « Aaron Rotenberg « Talk « 06:24, 20 November 2008 (UTC)

And, of course, weakly-ionized air smells of ozone, but feels like a regular air as far as the "moving through" is concerned. --Dr Dima (talk) 02:21, 19 November 2008 (UTC)

The very first victim of a weapon

Of course it's impossible to tell who was the first victim (in any species) of a malicious stabbing, or what human was the first victim of a gunshot, or who first paid the ghastly price of being cannon fodder. But is it safe to assume that the most exquisite Madame Curie was the first victim of the horrific weapon of high-level radiation? Sappysap (talk) 01:01, 19 November 2008 (UTC)

Girls who used luminous paint to paint numbers on clock and watch dials suffered from radioactive poisoning. They put the tip of their artists' brush in their mouth to get a sharp point. I don't know the dates on this, but it must have been before the danger was realized. —Preceding unsigned comment added by 98.16.67.220 (talk) 01:24, 19 November 2008 (UTC)

I suspect that some of our much more distant ancestors may have succumbed to cancer caused by exposure to naturally-occuring radon in their caves.

In the modern era, Marie Curie wasn't the first to be killed by radiation. Long before her death in 1934, a number of patent medicines began to include radium for various not-clearly-elucidated reasons. Eben Byers was one of the most famous victims of Radithor (sold from 1918-1928); he died in 1932. (See also radioactive quackery.)

Occupational exposure was also a problem. Unshielded x-ray tubes were widely used from World War I onward; many early radiologists likely died before Curie. As noted by the anon, radium jaw was widely recognized by 1925; I expect that at least some of those individuals died from their radiation exposure before Curie did. TenOfAllTrades(talk) 01:28, 19 November 2008 (UTC)

Madame Curie wasn't killed by a weapon. Also, in addition to all the other examples, I expect it wasn't very healthy to be around a natural nuclear fission reactor. Clarityfiend (talk) 01:35, 19 November 2008 (UTC)

I think the OP was talking about people. Not the bacteria that were around when natural nuclear reactors were active 2 billion years ago. — DanielLC 05:57, 19 November 2008 (UTC)

Hmmm...I thought they were a bit more recent. So what's a few billion years more or less? Clarityfiend (talk) 07:30, 19 November 2008 (UTC)

Clarence Madison Dally died in 1904 from the cancers caused by prolonged exposure to X-rays while an assistant to Thomas Edison. He started working with X-rays in 1895 and had serious radiation damage by 1900. In the early days, no one knew that radiation was harmful. Perhaps the first known victim of radiation? In the 1950's shoe stores still had X-ray fluroscopes to show how well shoes fit little children. They were basically World War 1 surplus X-ray machines. Kids would put their feet in the machine and push the button at every visit to the shoe store. Reportedly it harmed more shoe salesmen than it did children. They were shut down before 1960. Archie Frederick Collins, early 20th century science popularizer, wrote in "The Boy Scientist" (1925) detailed descriptions of how a child could build an x-ray machine and do lots of fun experiments with it. Edison (talk) 06:35, 19 November 2008 (UTC)

My 2c, correlation does not prove causation... Aaadddaaammm (talk) 18:56, 20 November 2008 (UTC)

As others have pointed out the Marie Curie example is flawed. But I guess the other question is, what is a weapon? It's clear the work of Marie Cure, as well as others mentioned above wasn't in any way related to weapons so I question whether you could call them the first deaths from the weapon of radiation poisoning. It's possible someone used some radioactive material as a poison beforehand but if not, the first deaths would surely either have been during the Manhattan project or Hiroshima. I presume there were deaths during the Manhattan project. One I found was Louis Slotkin [4] but I would say even in his case it's questionable if it was a weapon since what he was working on was subsiary to the main project and not really part of developing a weapon Nil Einne (talk) 13:17, 23 November 2008 (UTC)

What if we cut a hole through Earth?

On the Science Channel, they were saying that if we cut a hole all the way through the Earth such that it is a straight line, goes through the center of the Earth and comes out the other side, that if we dropped an object in the hole it would pass all the way though the Earth to the other side of the Earth, fall back down again and keep going forever. Even if we ignored friction/air resistance, this seems wrong to me. I'm wondering that once the object starts falling below the Earth's surface, the matter that is above the object would exert a gravitational pull and thus would slow down the object. Eventually the object would come to a standstill at the center of the Earth. Am I correct or am I incorrect? 67.184.14.87 (talk) 05:16, 19 November 2008 (UTC)

See Shell theorem. But briefly : The object would not become weightless until it hit the exact center. (Logically, that's the only point where the forces would balance out.) By that time it's going to be going about a zillion miles per hour.

So you're right that gravity would get weaker and weaker, But even weak gravity is going to make you speed up, not slow down. Without friction, nothing would slow you down until after you pass the center point. APL (talk) 05:33, 19 November 2008 (UTC)

You're right. I didn't say that properly. Whan I meant is that the gravitational pull of the matter above the object would decrease the rate of acceleration and after numerous passes through the Earth's core, the object would eventually slow down such that it comes at a complete rest at the center of the Earth. Or to put it another way, treating the Earth as if it's gravitational pull was concentrated at a point at its center is an oversimplification, that once it passes beneath the Earth's surface there is now matter above it that also exerts a gravitional pull in the opposite direction, and that the Science Channel's explanation ignores this graviational pull. (I'm the OP on a different computer.) 216.239.234.196 (talk) 13:56, 19 November 2008 (UTC)

Point 3 of shell theorem addresses this concern. Ues Image:Shell-diag-4.png for illustration. The mass "above" the object (that is, all grey area to the right of point m) exerts a retarding pull, yes. This is offset by the mass of similar altitude but towards the center (that is, all grey area left of point m), which exerts an accelerating pull. The latter has more mass but is further away, and calculus demonstrates that they balance precisely. More to the point, though, is that the process is symmetric. Regardless of actual values, you have no acceleration at the center point. 1 meter beyond the center point, you are decelerating at the same value with which you accelerated while 1 meter before the center point. 5000km out, the deceleration remains the same magnitude as the falling acceleration. Once you establish that you reach the antipode (and stop there, for some infinitesimal period), you're effectively back at your starting point with no degradation. Without outside influence (i.e. friction), then, your object never slows to stop at the center of mass. — Lomn 14:49, 19 November 2008 (UTC)

I would expect air resistance to slow it down and prevent it reaching the antipodal location. Also, I would expect it to rub against the side of the borehole due to conservation of angular momentum. At the surface, it was moving East at about 1000 miles per hour, if it started near the equator, but halfway to the center the hole would only be moving east half that fast, etc, resulting in extreme friction. But I was sometimes wrong in physics class. Edison (talk) 06:23, 19 November 2008 (UTC)

If you're going to talk about practical matters, it would be impossible to construct such a hole in the first place. The pressure in the center of the Earth is far in excess of anything that any known material could resist. But if friction is ignored, and the Earth is treated as a homogeneous sphere, and the hole was possible, then it's correct that the object would oscillate in a sort of linear orbit within the hole. Incidentally, this is also true for a straight hole through the Earth connecting any two points at the same elevation on the surface, no matter whether it comes near the center of the planet or not -- and the period of oscillation is the same for any such hole. I bet Wikipedia has an article on this, but I don't know what it would be called. --Anonymous, 11:24 UTC, November 19, 2008.

Edison is correct; unlesss the hole were cut directly down the Earth's rotational axis (north pole to south pole) any object dropped down would eventually smack into the side of the tunnel. Air resistance can be neglected through the simple expedient of capping both ends of the tunnel and pumping out the air. (If we're assuming the magical ability to construct this tunnel at all, surely we can assume sufficient magic to make it airtight.)

As an aside, I'm quite certain that this notion formed the core of a science fiction short story I once read. It involved an astronaut falling from space directly through the core of a planet. (Some sort of force field was being used to maintain the opening. I don't recall why the tunnel was there; I'm guessing mining.) Might have been Asimov who wrote it, but it could have been Niven. TenOfAllTrades(talk) 14:34, 19 November 2008 (UTC)

But wouldn't the falling object start with the same rotation as the Earth ? What would later cause it's rotation to vary from that of the Earth ? StuRat (talk) 18:02, 19 November 2008 (UTC)

An object on the equator travels 40000km/(sidereal) day parallel to the surface of the earth. But a point in 3000km down the tunnel (1/4 of the Earth radius) is only traveling 20000km/(sidereal) day parallel to the surface of the earth. So a free-falling object will always hit the leading edge of the tunnel on the way down. --Stephan Schulz (talk) 20:26, 19 November 2008 (UTC)

Something doesn't seem quite right about that logic. That would also mean that any vertical pipe would have the same effect, but to a lesser extent, resulting in one side of the pipe wearing out more quickly because the fluid keeps ramming into that side of the pipe to increase or decrease it's rotational speed (depending on if the fluid is going up or down). Has any such effect ever been noted ? StuRat (talk) 01:17, 20 November 2008 (UTC)

There's nothing wrong with the logic; this is simply a form of the Coriolis effect. Remember, it applies to all motion that is in a rotating reference frame, and not along the actual axis of rotation. (So for a shaft between the North and South Poles, this would not be an issue.) It applies in a vertical pipe, a horizontal pipe, or any other direction -- but in any situation in the ordinary world, the magnitude of the force is so tiny as to be insignificant. See also Steve Baker's reply below. --Anonymous, 04:41 UTC, November 20/08.

While not practical on Earth due to the magma, would drilling a hole through the Moon or a smaller body actually be possible ? StuRat (talk) 18:01, 19 November 2008 (UTC)

"Magma" isn't really relevant; the point is the immense pressure at the center of a planet. For the Moon it would be less, but I'm sure still plenty enough to collapse any tunnel in the rock. That said, I'm not sure exactly how you compute it -- anyone know the formula or where to find it? Of course with a small enough body, like a small asteroid, the gravity is so light that it would be practical. --Anon, 04:45 UTC, November 20/08.

Magma is indeed relevant, as such liquid rock is due to high temperatures which would melt the lining of any tunnel. StuRat (talk) 07:00, 22 November 2008 (UTC)

Oh, and again, if you're thinking of actually trying this, be sure to consult the local building code on the asteroid. :-) --Anon, 04:47 UTC, November 20/08.

A lot of asteroids are believed to be piles of loose rubble, so you would need to build a retaining wall around your tunnel. The asteroid itself would just collapse in on itself, even at the surface. --Tango (talk) 23:32, 20 November 2008 (UTC)

We talked about this a couple of times before - and someone calculated that the air pressure in the center of the tunnel would be so high that the air would liquify. So the tunnel has to be pumped down to a nice, hard vacuum for you to be able to fall through it. Unless the tunnel is dug through from pole to pole, the coriolis forces also prevent you from falling cleanly down through the tunnel without hitting the sides. SteveBaker (talk) 19:11, 19 November 2008 (UTC)

To what does 'bi' refer in 'bicarbonate'?

To what does 'bi' refer in 'bicarbonate'? ----Seans Potato Business 12:31, 19 November 2008 (UTC)

It refers to the fact that the ion takes half of the positive ions that sodium carbonate did. They were named before the actual structure of the ions were known; but what was known was that with roughly equivalent masses of carbonate and bicarbonate, the carbonate took twice the mass of, say, sodium to form sodium carbonate as it did to form sodium bicarbonate. Once the actual structures of the ions was later discovered, it turned out the same was entirely inaccurate, but it stuck. --Jayron32.talk.contribs 12:47, 19 November 2008 (UTC)

So what's the correct name for sodium bicarbonate? --70.167.58.6 (talk) 15:32, 19 November 2008 (UTC)

sodium hydrogencarbonate? Sjschen (talk) 15:51, 19 November 2008 (UTC)

Generally "sodium hydrogen carbonate" is the formal, IUPAC name, but as with most common compounds, even chemists find the formal names somewhat pedantic, and will commonly use the older, more common names, such as "sodium bicarbonate". For example, no chemist would use the more formal "ethanoic acid" where "acetic acid" is the more accepted, common name; or would use "2-propanol" (IUPAC name) where "isopropanol" or "isopropyl alcohol" is more common. --Jayron32.talk.contribs 17:52, 19 November 2008 (UTC)

Does WP have a list of such "wrong but stuck" scientific terms? —Tamfang (talk) 09:12, 20 November 2008 (UTC)

They aren't "wrong" any more than any part of a workable language is "wrong". There are formalized versions of English, for example, but that does not make the non-formal versions of English "wrong" in the way that the answer to a mathematics problem can be "wrong". As long as everyone in the audience of the speaker has an unambiguous understanding of the content of their speach, it is perfectly valid language; regardless of its adherance to a set of formalized rules. The IUPAC rules actually work very well for medium-sized compounds. Very large compounds start to take on confusing and cumbersome names; while smaller compounds which were well known before their implementation retained their names because it made sense; there was already thousands of pages of literature that referred to these compounds, so it made little sense to "change their names" as such a change (such as everyone all of a sudden starting to call acetic acid as "ethanoic acid") would likely lead to MORE confusion; and the IUPAC rules are all about causing LESS confusion by providing an unambiguous nomenclature system. Using terms like "sodium bicarbonate" or "acetic acid" is not wrong in any sense... --Jayron32.talk.contribs 14:17, 20 November 2008 (UTC)

Okay then, does WP have a list of scientific terms that, although not wrong, do not mean what an otherwise knowledgeable person would infer by the usual conventions of the field's terminology? —Tamfang (talk) 08:49, 21 November 2008 (UTC)

I was taught at school that the bi means hydrogen. No explanation was given.--GreenSpigot (talk) 01:24, 21 November 2008 (UTC)

The color of shower gel

I have noticed that while shower gels come in a wide variety of colors (the ones I usually use are red or brownish-yellow), the water when taking a bath always has a bluish-green tint, no matter what brand/color of shower gel I use. What exactly is happening here? -- Ferkelparade π 12:48, 19 November 2008 (UTC)

Shower gels are coloured with small amount of dyes. While it shows up in the bottle, the amount of dye in one use of the gel is likely not enough to change the colour of the large quantity of bathwater, which I think gets its greenish-blue colour due to the Tyndall effect or Rayleigh scattering. -Sjschen (talk) 15:50, 19 November 2008 (UTC)

Actually, blue-green bathwater is more likely due to oxidized copper in the water. The water source may have the copper, or it could be coming from corroding copper pipes. ~Amatulić (talk) 02:23, 22 November 2008 (UTC)

Restrictive NAT on DSL modem?

--moved to computer desk--- --71.158.221.237 (talk) 02:34, 20 November 2008 (UTC)

stupid question -- water filters filter flouride or no?

Sorry this is a dumb question, but ... water filters like Brita won't keep me from benefting from the medicamentous flouride with which the water supply is laced, will they?

According to Brita's FAQ: [5] "The BRITA Water Filter System does not remove fluoride from tap water. Fluoride is a negatively charged ion and does not react with the components of the BRITA Filter Cartridge." I don't know if other filters use the same process. Fribbler (talk) 16:00, 19 November 2008 (UTC)

See Water fluoridation. Flouride cannot be filtered out of water, but it is debated whether fluoridation is of any benefit to adults.--Shantavira|^{feed me} 18:34, 19 November 2008 (UTC)

But fluoridation still seems like a good idea, whether it assists us only in childhood, adultery, or both. StuRat (talk) 01:11, 20 November 2008 (UTC)

StuRat must value teeth free of caries in extramatrimonial affairs...XP 152.16.15.23 (talk) —Preceding undated comment was added at 02:10, 20 November 2008 (UTC).

Yes, an adulterous woman already is looking to have one cavity filled, what does she need with another ? StuRat (talk) 23:34, 20 November 2008 (UTC)

It's not her hydroxyappetite that is the problem. DMacks (talk) 01:43, 21 November 2008 (UTC)

We're hearing lots of news about the adverse effects of fluoridation these days. Besides, the flouride barely even touches your teeth, it just goes down into your stomach and through your body. Reports are that fluoridation may be correlated to mental retardation, if I remember correctly. Also, don't be afraid to ask questions, there are no "stupid" questions. I also have a similar question: if water is boiled, does it remove fluoride? ~AH1^(TCU) 16:08, 22 November 2008 (UTC)

It can still get into the teeth from the roots, via the bloodstream. As for boiling, I would expect it to stay in the pan after the water is boiled, as part of the mineral crust. So, what's boiled off and recondensed (distilled water), would indeed have the fluoride filtered out. StuRat (talk) 16:35, 22 November 2008 (UTC)

Apple trees

How many years does it take an apple tree to bear fruit, counted from the time the apple seed was planted? —Preceding unsigned comment added by 207.210.129.15 (talk) 19:40, 19 November 2008 (UTC)

Apple trees aren't really grown from seeds. You can probably plant an apple and get a tree out of it, but you will probably not get any fruit resembling the apple you planted. All commercially planted apple trees, even ornamental crabapples and the like, are propagated by grafting. --Jayron32.talk.contribs 20:08, 19 November 2008 (UTC)

If you get apples at all, why wouldn't they resemble the "parent" apple? What does the rootstock contribute to the quality of the fruit? —Tamfang (talk) 09:10, 20 November 2008 (UTC)

This issue is with apples' ease of mutation, which is one of the reasons why there are so many varieties of apples (several thousand, iirc). You get an apple tree when you plant an apple seed, but you wouldn't get a granny smith apple tree by planting a granny smith apple seed. That's fine if you're just growing something for the backyard, but a pain in the ass if you're trying to sell a recognizable brand. Matt Deres (talk) 16:07, 20 November 2008 (UTC)

Uhh I believe that's due to pollination and the ease of recombination. It's not that apples mutate easily -- it's the fact that so many apple traits (that were bred through husbandry) are caused by relatively few genes. A lot of apples can mate with wild flowers from other trees that are actually quite genetically close to apples, though morphologically they look much different. John Riemann Soong (talk) 07:27, 25 September 2010 (UTC)

Jayron's correct, but I'll answer anyway: 2 to 5 years (source). --Sean 20:12, 19 November 2008 (UTC)

So why wasn't he called Johnny Grafter? Deor (talk) 23:15, 19 November 2008 (UTC)

Because graft is left to the politicians. StuRat (talk) 01:07, 20 November 2008 (UTC)

Johnny Appleseed really did spread seeds and not grafts; however none of his apple orchards were for eating. People didn't really eat apples (well, maybe a few), but just like most grapes went into wine production; apples were primarily used to make hard cider and apple brandy. You could make far more money per tree producing liquor than fruit; and when you are just after the fermented products, then producing a consistant tasting fruit isn't probably high on your list of important traits... --Jayron32.talk.contribs 02:15, 20 November 2008 (UTC)

People always ate apples [6]. They could be dried and eaten during the winter in fried pies or other confections long after the last apple in the barrel had been eaten or had rotted [7]. Cider, hard or otherwise was a fall use of apples, but dried apples kept over the winter without refrigeration or canning. (Edit) I agree that good tasting eating apples come and mostly came even in Chapman's day from the grafting of the tasty mutant apple limbs onto less tasty root stock, but that the root-stock aples coming from the seeds Chapman picked out (for free) from the pulp at a cider mill would still make good cider. The genetic reason why seeds from a tasty apple woulkd not ever produce trees yielding tasty apples is very unclear. Why wouldn't seeds from, say a Paula Red or a Granny Smith produce offspring trees of varying tastiness, with some tasting like the source apple? Crops like potatoes were improved by using the eyes from the best to produce the next crop. Same for corn (maize), or tomatoes before modern hybrids, with seed from the ones with the most desirable characteristics used for the next crop. Edison (talk) 06:05, 20 November 2008 (UTC)

Are there more extreme temperatures (way above or below average?) than years ago?

In discussing our weird wether, and how it's been weirder than normal the last few years, a friend and I deduced that the main thing is the number of days with temperatures way above or below average.

I was wondering if there was a rather easy way to determine whether there have been, in fact, more highs at least 10 degree Fahrenheit above or 10 degrees below average in the last 5 years than in a similar stretch, say, 30 years ago. Have any studies been done about this?

This may seem arbirtary, but considering the normal temperatures in the Great Lakes region of the United States, this sounds like a reasonable level. Of course, there will always be times when temperatures are unusual, but it seems that 10 degrees above or below is unusual enough that, when weather functions normally, it would be at least somewhere rare, whereas in his words, "now it seems like you go right from summer to winter and back again without a fall or spring."Somebody or his brother (talk) 20:54, 19 November 2008 (UTC)

Even if this were true, it doesn't necessarily mean much. What I mean by that is that we have probably less than 200 years of reliable daily temperature data to work with. That's not really enough to wash out the "noise" of random results and really determine if such statistics were causal or random. Let me give you another example. Lets say I threw a die 200 times. Now, I should get each face of the die about 1/6th of the time; but if I look at a small, localized subset of the 200 times I throw the dice, say the last 20 throws, and see that 6 came up like 7 or 8 times, it wouldn't mean that the dice was "loaded". Random chance says that during substantially small subsets of data, there will be "streaks" that aren't causal at all; in fact the laws of probability say that any random set of numbers is far MORE likely to feature such streaks than to lack them (for example, having 100 rolls of the dice with NO consecutive repeats is FAR less likely than having 100 rolls of the dice and having say, 6 come up 3 or 4 times in a row). Now, given all of this, it does not mean that global warming or climate change is NOT happening. Daily temperatures are part of the weather, and daily weather is so variable it is impossible to predict trends with any certainty. Global warming is about climate, which can be predicted quite well. Lets go back to the 200-throw-of-the-dice analogy. If 8 of my last 20 throws came up 6, it probably wouldn't mean much, but if say the average number, if I say added all 200 throws and divided by 200, turned out to be like 4.7, then we would CERTAINLY say that something fishy was up. That's what we have with climate change; while local places on earth may or may not have seen any "weird" weather in any given year, when averaged over the last few centuries, there is definite evidence of playing with "loaded dice"...

Also, it should be noted that the Great Lakes region is probably a bad example to use; areas near the centers of continents always feature much more dramatic temperature swings than areas near the coast. It is not uncommon for high temperatures from day to day in Illinois to swing more than 20-30 degrees, or to see the temperature drop 40 degrees in a matter of hours. Finding the same swings in, say, Boston is much more unusual. --Jayron32.talk.contribs 21:24, 19 November 2008 (UTC)

Thanks; that makes sense now. Yeah, i tend to forget just how little reliable data we actually have. And, I hadn't thought about the difference between the coasts and inland; I don't know if I'm just not catching it or they're not explaining it well on the news (probably a bit of each, little blurbs can't include everything) but it always seems like they're implying, "This stuff is happening everywhere at the same time" to me.Somebody or his brother (talk) 22:55, 19 November 2008 (UTC)

It may be, but it may or may not mean much. The local TV news doesn't even understand basic logic, such as the fallacy post hoc ergo propter hoc, and does not understand the difference between "correlation" and "causality"; much less understand the complexity of the science of climate change. I have no doubt that climate change is occuring personally, however I also don't expect to be able to correlate such changes to actual single weather events. --Jayron32.talk.contribs 23:04, 19 November 2008 (UTC)

And worse still, they ALWAYS confuse 'weather' with 'climate'. One random hot day that breaks all records doesn't prove that global climate change is true - and one random cold day doesn't disprove it. Even an entire year of record temperatures wouldn't do that. Weather is the short-term and very localised change - climate is the reactions of large chunks of the planet over many years. I think it's likely that dramatic climate change may indeed result in more wild weather swings - and therefore more records broken - but that's very much a secondary thing compared to the relentless grind of steadily increasing global average. SteveBaker (talk) 02:50, 20 November 2008 (UTC)

If you are talking about global warming here, there are many factors that influence temperature range. Nowadays, there are urban heat islands that cause hotter weather during summer daytimes, and effects associated with global warming such as the shrinking of inland lakes and the possible slowing or shutdown of the thermohaline system may cause more drastic temperature differences between hot and cold. However, since global warming itself tends to reduce the temperature contrasts, such as that it produces more warming at the poles than in the tropics, more at higher altitudes than lower ones, more warming at night than during the day, and more warming in winter than in summer, it may reduce this effect. ~AH1^(TCU) 16:01, 22 November 2008 (UTC)

Levoglucosan

what are ' Levoglucosan'? —Preceding unsigned comment added by Balukri4 (talk • contribs) 22:20, 19 November 2008 (UTC)

The search function is wonderful. I typed the above word in the search box to the left, and came up with the following, from the article Smoke: "Levoglucosan is a pyrolysis product of cellulose." Then I typed the same word in google, and came up with the following page: [8] which says "Levoglucosan (1,6-anhydro-β-d-glucopyranose), a major constituent of smoke from biomass burning,". So, there you go. Its basically a sugar. --Jayron32.talk.contribs 23:01, 19 November 2008 (UTC)

Do not, under any circumstances, trust that Wikipedia's search engine will find the results you desire. I love Wikipedia, as does everyone reading this, but its search engine lacks much to be desired unless you articulate things absolutely precisely, or you're feeling lucky. If you need to search this ungodly compendium for X, go to google and type "X site:wikipedia.org" For all you reading: is this heresy? I'm not a zealot in anything I ever have to say. Just a pragmatist. Show me a more rigorous way of searching this Hitchhiker's Guide to the Galaxy, and I will be so grateful. I only ask that you start the guide with the words: Don't Panic Sappysap (talk) 02:11, 20 November 2008 (UTC)

Except that, in this case, it did. The deal is, one should at least type the word into the Wikipedia search engine and into google BEFORE asking the question here. It took me longer to type my response than it did to find the information I posted above. C'mon, at least put forth an effort! --Jayron32.talk.contribs 04:03, 20 November 2008 (UTC)

It should also be noted that now the wikipedia search has the suggest function enabled things may be somewhat better then before. Having said that, a search for Levoglucoson suggests Levlawson with the wikipedia search (on Google it's Levoglucosan) Nil Einne (talk) 01:24, 21 November 2008 (UTC)

Nuclear Science

Why does the binding energy per nucleon even matter? The binding energy is the amount of energy that must be put into the nucleus to break it apart, so why do we need to figure the energy per nucleon? TIA, Ζρς ι'β' ^¡hábleme! 22:53, 19 November 2008 (UTC)

Three reasons I can think of: the binding energy of the entire nucleus is the energy required to separate each nucleon from every other nucleon (ie. disintegrate the entire nucleus), which rarely happens (except for heavy-ion collisions such as those done in RHIC). Much more common is that "a few" (probably four, in the form of an alpha particle) nucleons are ejected. The second reason is that when viewing a plot of total binding energy vs. atomic mass, there will be a linear factor involved that will obscure other features; normalising the plot to binding energy per nucleon allows us to see certain trends like "closed shells". The final reason is that binding energy per nucleon roughly corresponds to stability; if I have some set number of nucleons the most stable configuration would be to arrange those nucleons into nuclei of the largest binding energy per nucleon (I think it's Iron-56). 58.96.70.254 (talk) 23:12, 19 November 2008 (UTC)

Actually it is Nickel-62, although Iron-56 does have the lowest mass per nucleon. --130.88.47.42 (talk) 13:36, 21 November 2008 (UTC)

When you have a nuclear reaction, you don't generally conserve nuclei, but you do (usually) conserve nucleons. So if, as is common with normal fission and fusion reactions, all the products have energies per nucleon that are higher (lower) than all the reactants, you can immediately say that the reaction is endothermic (exothermic) without further analysis and without having to consider each particle separately. --Tardis (talk) 23:48, 22 November 2008 (UTC)