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June 10

Crystal Glass

What is crystal glass and its special properties? —Preceding unsigned comment added by Sksinghaijbp (talk • contribs) 00:09, 10 June 2010 (UTC)

Crystal glass is a common name for lead glass. It is glass with substantial proportion of lead oxide in the mix, typically around 30% by weight. The lead content increases the refractive index of the glass, which means it sparkles more (because of total internal reflection); it also means that crystal glass is notably denser than normal glass. Physchim62 (talk) 00:27, 10 June 2010 (UTC)

And also has a lower softening point, which allows it to be shaped more easily. 67.170.215.166 (talk) 06:29, 10 June 2010 (UTC)

Growing fruits & vegetables indoors...

Possibly an extremely stupid question... if one was to grow beans, or tomatoes, or what have you indoors - wherein there would be no natural pollinators (insects, wind, etc.) would the plants still produce vegetables/fruit? should the owner attempt manual fertilization by swabbing pollen around with ... swabs or something? 218.25.32.210 (talk) 00:53, 10 June 2010 (UTC)

AFAIK beans (Phaseolus) self-pollinate. However, tomatoes do not, see Buzz pollination. --Dr Dima (talk) 01:24, 10 June 2010 (UTC)

And BTW this is not a stupid question at all; it is a very good one. Regarding the cotton swabs -- they work for some plant species but not for others. --Dr Dima (talk) 01:28, 10 June 2010 (UTC)

You can grow most food plants without polination or seeds even, see Grafting, and especially Tomato grafting which details how the method is used for indoor growing of tomatoes in light of the exact problems the OP notes. --Jayron32 01:46, 10 June 2010 (UTC)

Pikachurin 3D structure

Where can I find an image of the 3D structure of pikachurin? --75.25.103.109 (talk) 00:58, 10 June 2010 (UTC)

I don't think it is known. Working out the 3D structure of proteins is extremely difficult at best, and this protein was only characterized last year. See protein folding for more information about why the problem is difficult. Looie496 (talk) 01:18, 10 June 2010 (UTC)

But they know its sequence (otherwise they couldn't engineer pikachurin-null mice for their experiments), so can't they determine how it will fold based on the order of amino acids? --75.25.103.109 (talk) 01:24, 10 June 2010 (UTC)

Nope. The cellular machinery that synthesizes proteins is excellent at getting them to fold into their native conformation (and other chain-chain interactions). We're very far from being able to predict that result from an arbitrary sequence. In some cases we can recognize certain sequences as being helix domains or other local shapes based on homology modeling from other known protein structures. As Looie496 said, "See protein folding for more information about why the problem is difficult." It's even worse than you think, I think, because you only need a few genetic markers in order to to gene knockout. For example, it might be sufficient to inhibit a promoter or other "start" sequence, or just delete a huge chunk of genome--I can't access the Nature article to see exactly what they did. But not all of the gene base-sequence might be used anyway (see intron), so "the order of amino acids" might not be known. And there might be other post-translational modifications that are critical for certain structural features but are definitely not knowable from just the amino-acid sequence. DMacks (talk) 02:14, 10 June 2010 (UTC)

Not to contradict any of that, but perhaps to clarify a bit, working out the sequence of amino acids is cheap and easy nowadays. Working out the 3D structure is orders of magnitude harder. In fact it is only feasible in special cases, such as proteins that can be crystallized. Finding a general method for predicting the 3D structure of a protein on the basis of its amino acid sequence is currently by far the most important unsolved problem in molecular biology. Looie496 (talk) 03:49, 10 June 2010 (UTC)

What if... we're the only intelligent life

There's ongoing research as to life on other planets. What if we discover that we're the only intelligent life that we can ever travel to? Would we continue to fund extra-terrestrial expedition? If we are never going to get to where other life exists and (presuming) they would never be able to get to us (of an intellectual nature) then what would be the point in spending exorbitant amounts of money, given that we are in a global recession? Is there any research into finding ETs that might have landed on Earth that might be too small for us to detect - tiny tiny aliens landing on Earth daily who might not even realise that people are people and have developed civilisation similar to their own. Sorry to ask so many questions all in one go, but they are inter-related. --russ (talk) 01:11, 10 June 2010 (UTC)

The initial question is moot, as you can't prove a negative. As for the rest -- no referenceable answers are possible. — Lomn 01:31, 10 June 2010 (UTC)

"Exorbitant amounts of money" should be put in perspective. The world spends many, many times more money on national defense every year than on space-related sciences. And another general point - we needn't go to another lifeform's location to communicate with it. Radio-based communication is already doable, provided we know someone else is listening. 218.25.32.210 (talk) 01:33, 10 June 2010 (UTC)

Given our understanding of the laws of physics, the first question's answer is undoubtedly "We are the only intelligent life we can ever travel to." Period. The nearest stars to ours would require many centuries earth time to reach, such that any report of such missions reaching distant worlds would be received by an Earth which may have forgotten the details of the mission thus sent. The topic has been explored in song by the band Queen, the song '39, which explores the problem of time dilation in space exploration. And before we poo-poo the idea of a pop-song about a scientific topic, remember that Brian May, the writer of said song, has a PhD in astrophysics, which means he probably has a deeper understanding of the topic of the OP's question than almost any one here... --Jayron32 01:43, 10 June 2010 (UTC)

NASA Budget has some annoying numbers, but the TOTAL expenditure on NASA in 2007 dollars has been either $416 billion or $807 billion, averaging $8 or $16 billion a year, respectively. From that same article, the aerospace industry (of which NASA is the largest, not sole, member of) "contributed more than $95 billion to U.S. economic activity." As a means of comparison, according to Military budget of the United States, the military expenditure for 2010 is/will be somewhere between $880 and $1000 billion. That may be a tad disingenuous since the military is the largest portion of the budget, but Medicare/aid and Social Security aren't far behind; the point stands, though - aerospace is not a huge source of spending, and almost certainly gives back more than it takes. (I'm using NASA since it's a. the largest of it's kind, b. our articles on the US are better/easier to find info on, and c. other agencies/countries aren't looking nearly as closely as the USA is.) ~ Amory (u • t • c) 14:07, 10 June 2010 (UTC)

Indeed, the dropping of the Orion spacecraft could easily be avoided if we went without an extra stealth bomber. Not that I disagree with the project's cancellation, mind you.-RunningOnBrains^(talk) 14:49, 10 June 2010 (UTC)

Before saying that the answer is undoubtedly that we are the only intelligent life we can ever travel to, take into consideration that it was once deemed impossible for man to sustain powered flight, and that I am told many felt the same way about breaking the sound barrier. Certainly within our understanding of physics we can't travel to other planetary systems, but that's assuming that we understand everything that we can about physics. I guarantee that in two-hundred years, some of our theories will be laughed at by our descendants (assuming, of course, that we don't destroy civilization before then). Falconus^{p t c} 04:02, 10 June 2010 (UTC)

Well, of course. If the world doesn't work how we think it works, then all bets are off. Magic fairies may someday take us to fantastical lands where we never grow up, but given that we don't have any evidence of such fairies existing, we must operate as if they do not. Likewise, until the real problems of the speed-of-light limit are shown to be false, we shouldn't operate as though it is really possible. If we ignore the laws of physics as we understand them to behave, then there's no need to confine ourselves to any reasonable answer within those laws. We could just travel to far away planets by flying carpet for all that matters... --Jayron32 04:48, 10 June 2010 (UTC)

See Fermi paradox. We might start to terraform other planets in the absence of life. ~AH1^(TCU) 01:59, 10 June 2010 (UTC)

It's of note that the prospect of hanging out with intelligent life was never the official justification for space research and exploration. There are lots of other reasons to think that exploring space is a worthwhile endeavor (to at least certain costs). --Mr.98 (talk) 02:18, 10 June 2010 (UTC)

What if is not a very good title for a qustion. Dauto (talk) 02:22, 10 June 2010 (UTC)

I changed it. Ariel. (talk) 04:02, 10 June 2010 (UTC)

What does a global recession now have to do with spending money on space faring pursuits over a time span of hundreds or thousands of years? Dismas|^(talk) 02:52, 10 June 2010 (UTC)

I'm not sure who you're asking, but there's a real chance that we may have a limited window to take certain first steps. Energy and raw material shortages could make such big science projects more and more political unfeasible. The irony would be that a more advanced space program would help solve these issues, but if the underlying technologies haven't already been explored there's a chicken-egg problem. APL (talk) 05:18, 10 June 2010 (UTC)

to reiterate what Falconus said, the nature of science is such that every scientific claim implicitly ends with the phrase "...given our current state of understanding." The scientists 50 or 100 years from now will be just as astounded by our ignorance as we are astounded by the ignorance of people who believed in alchemy and divination. I mean really: Benjamin Franklin was a very bright guy by any standards, but he would have laughed at the idea that people could get from the Americas to Europe in a matter of hours by flying through the sky in a big metal tube, higher than any bird. --Ludwigs2 07:32, 10 June 2010 (UTC)

Nitpicking, but your scales are off. 50 years ago was the start of the space age, and 100 was a few years past the airplane. If you want to compare to Ben, you gotta look to 2250. ~ Amory (u • t • c) 13:43, 10 June 2010 (UTC)

nitpciking your nitpick, but you seem to think that technology is linear, where technology seems to be a more exponential model. Googlemeister (talk) 14:36, 10 June 2010 (UTC)

Uhm I'm in a position to give an authoritative answer. Intelligent life does exist outside this solar system and there is travel between different civilizations, even over distances of millions of light years. The human civilization on Earth, however, is not regarded to be a real intelligent civilization by most of these civilizations, though. To qualify, a civilization must have developed the technology to expand itself at an exponential rate. Human civilization has yet come up with any production process that is capable of exponential growth. E.g. think of nano-tech factories that can copy themselves.

Obviously, all the civilizations that meet the criterium for being an intelligent civilization, are machine civilizations. In some of these machine civilizations, the ancesteral biological beings are kept in Zoos or Wild parks. Population control usually proceed along these lines.

Despite the inferior nature of human civilization, I find the lack of imagination in this thread about space travel strange. I mean, isn't it obvious that space travel between civilizations happens using data transfer via wideband communication channels? If you want to transfer a file to someone living far away, you don't put your computer in your backpack and travel all the way to the destination, either! Count Iblis (talk) 14:50, 10 June 2010 (UTC)

... Nimur (talk) 15:30, 10 June 2010 (UTC)

No...but if you want to travel to Prague you don't send someone in Prague an email. ~ Amory (u • t • c) 16:01, 10 June 2010 (UTC)

When you travel to Prague what you are doing is carry your brain to Prague. If your civilization were more advanced, your brain would run on some machine and you could upload it to a compatible machine in Prague. Count Iblis (talk) 16:24, 10 June 2010 (UTC)

So then would the consequences of a blue screen of death be literal death? Googlemeister (talk) 19:06, 10 June 2010 (UTC)

It must be pointed out that when a country spends a lot of money to create and launch a space probe, the country does not just gather a big pile of taxpayer cash and launch the money at Neptune, never to be seen again. Most of the money is paid over the years to the scientists, engineers, technicians, administrators, and other staff who work on the project, whether they're government employees or private vendors. All these people then use the money to pay rent, buy food, and go to the movies. Keynesian economics claims, among other things, that government spending like this increases demand and consumption, thus boosting and not degrading the economy. Also see the Government spending article. Comet Tuttle (talk) 19:33, 10 June 2010 (UTC)

1. What if we discover that we're the only intelligent life that we can ever travel to? -- I think we have already more or less realized that this is true. There does not appear to be any intelligent life other than us within our solar system - and getting to even the nearest other star is close to impossible. If we don't find intelligent life within (let's say) 50 light years (and we've certainly studied those few stars pretty carefully) - there is essentially zero chance that humans will ever go there in person. We just don't live long enough and the speed of light is a harsh mistress!
2. Would we continue to fund extra-terrestrial expedition? -- Evidently we do! Yes!
3. If we are never going to get to where other life exists and (presuming) they would never be able to get to us (of an intellectual nature) then what would be the point in spending exorbitant amounts of money, given that we are in a global recession? -- You have subtly switched from asking about intelligent life - to life in general. We are spending modest amounts of money looking for non-intelligent life in our solar system - but there are good chances that that could be successful. Outside of the solar system, really, the SETI program is the only substantial effort to look for intelligent life - and that organization is run on a shoe-string. But there would be immense value to humanity just to know that we are alone - or not alone...either way would probably have a fairly profound effect on us. Even finding unintelligent life with the solar system would tell us a lot about evolution and where we come from. If we found intelligent life within a reasonable number of light years, we could communicate with them by radio or perhaps laser and exchange knowledge. That would certainly be an exciting and valuable prospect.
4. Is there any research into finding ETs that might have landed on Earth that might be too small for us to detect - tiny tiny aliens landing on Earth daily who might not even realise that people are people and have developed civilisation similar to their own. -- Not really. There are quite serious limits to how small something can be and still have enough brain power to be called "intelligent". Notice that our computers are coming close to the limits of "Moores' Law" and they are nothing like powerful enough to be intelligent. The volume of the human brain is likely to be close to the smallest it can be for our level of intelligence...I would be very surprised if a life-form smaller than a mouse could possibly have enough computing capacity to be intelligent. So there is really no point in looking for microscopic-but-intelligent life. However, unintelligent "aliens" could easily be here in the form of bacteria and viruses that travelled here by comet or meteor from other planets or even further afield. The "panspermia hypothesis" suggests that it's possible that all life on earth originated elsewhere in the universe - and that we're all (in a sense) "alien".

SteveBaker (talk) 00:24, 11 June 2010 (UTC)

I would point out, with regard to your point 1, that we might someday live longer. --Trovatore (talk) 00:27, 11 June 2010 (UTC)

We might - (although you'd need to be able to live for a few thousand years, cooped up in a tiny spacecraft, living on the same recycled food/water/air...that's one hell of a stretch!) but it would be wrong to conclude that SETI carry on their search in the hope that human lifespans will someday be long enough that we can travel the 100 light years it might take to get to the nearest intelligent aliens. They are doing it purely for the answer to the simple yes/no question "Is there anyone out there?" - even if they found an alien civilization via a radio message, it's very unlikely that anyone alive today would live long enough to talk to them! This is simple human curiosity - it has nothing to do with whether we might travel to meet aliens. SteveBaker (talk) 00:45, 11 June 2010 (UTC)

If we compare human colonization of other planets to human history then we are early humans stuck in a small range in africa. Eventually I think we will spread throughout the galaxy through colonization, although in small leaps of a few lightyears over a very long time, none of the colonies knowing of many others or being able ot contact many others. If a faster method of travel is ever discovered, then that will be like the beginings of current civilisation and as it is refined, exponential growth until the colonial age and now.--178.167.179.162 (talk) 22:59, 11 June 2010 (UTC)

Interesting properties of acetic acid

Hi. The chemical structure of acetic acid (CH₃COOH) appears to have the same number of each atom as the combination of methane (CH₄) and carbon dioxide (CO₂). Could lightning, for example, split the molecules should it strike vinegar and convert it into these two greenhouse gases? Could it similarly form acetic acid from the gases? Also, assuming that the acid is an aqueous solution, removing the water molecule produces C₂H₂O. Again separating H₂O would produce water and C₂, or diatomic carbon. Could a reaction between carbon and water from lightning, or even in carbonic acid, produce acetic acid (and oxygen, in the case of carbonic acid)? Could this be a useful way of obtaining vinegar by manufacturing it, or even producing hydrogen electricity by obtaining the hydrogen from the acid, or would that apply to all acids as well as water? As an aside, when metals react with strong bases such as sodium hydroxide and a thin layer of bubbles coats the metal, do the bubbles contain both hydrogen and oxygen gas? Thanks. ~AH1^(TCU) 02:28, 10 June 2010 (UTC)

See the articles Carboxylation and Decarboxylation. The addition of carbon dioxide to methane to form acetic acid is an unsurprising reaction, as is the reverse, and these are routinely discussed in introductory organic chemistry classes and textbooks. A very similar reaction to what you describe, using electricity, is noted at Kolbe electrolysis. --Jayron32 02:50, 10 June 2010 (UTC)

Metals - just hydrogen gas in the bubbles.83.100.132.26 (talk) 15:12, 10 June 2010 (UTC)

Tiger question (not about the big striped cat)

Suppose an Allied commando team steals a Tiger tank from the Nazis and, while driving it toward the Allied lines, encounters another Tiger. Would the two Tigers be able to destroy each other, or would they end up shooting at each other without effect like the Monitor and the Merrimack? Or does it depend on their position relative to each other? (Assume that they both have identical 88mm guns and standard armor.) Thanks in advance! 67.170.215.166 (talk) 03:15, 10 June 2010 (UTC)

In Kelly's Heroes, a highly underrated movie, the point is made that the Tiger was quite weakly armored in the rear. So even if they could stand each other off face to face (which I'm not sure about), you would get an interesting situation once one passed the other. Looie496 (talk) 03:38, 10 June 2010 (UTC)

According to http://www.worldwar2aces.com/tiger-tank/ "Depending on the type of ammunition used, the Tiger's 88mm has a muzzle velocity of 930m per second and could penetrate up to 110mm of armor at a distance of 2000 meters"

According to http://www.fprado.com/armorsite/tiger1.htm the armour was 80mm at the rear, 100mm at the front at mostly nearly verticle angles, and 120mm around the gun mantle.83.100.132.26 (talk) 13:54, 10 June 2010 (UTC)

Clearly rear and side shots would work, frontal shots - don't know.. It's worth reading the whole article - thickness is one factor, quality is another - the tiger steel was rolled nickel alloy plate . it's not clear to what type of armour the penetration figures refer.83.100.132.26 (talk) 13:57, 10 June 2010 (UTC)

Even if you can not penetrate the armor in one hit, you could still cause damage. Spalling, hits to unarmored areas like tank tracks, multiple hits to one area of armor can all take a toll. Also, the above chart is done at a range of 2000 meters. If you are only 200 meters, your shot should have at least some additional power, perhaps enough to penetrate the armor anywhere on the tank. In the battle between bullet and armor, bullet almost always has the upper hand. Googlemeister (talk) 14:51, 10 June 2010 (UTC)

baking soda

why cant u eat baking soda unless its dissolved in water first. it says not to on the box, that it will cause some kind of severe stomach problem like bleeding ulcers or something. what will happen? —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 03:47, 10 June 2010 (UTC)

Its probably a liability issue. Eating straight baking soda could cause problems because of the rapid release of carbon dioxide gas in your stomach, and the company needs to cover its ass by saying not to do it, so that you can't sue them if something goes awry. Baking soda certainly has medicinal uses, see Sodium_bicarbonate#Medical_uses, but the people who make boxes of baking soda are probably understandibly going to discourage you from using their product, unregulated, as a medication. --Jayron32 03:58, 10 June 2010 (UTC)

it says it fine eat use as long as u dissolve it in water first and drink it. why cant u eat it as a dry powder though? what kind of stomach problems can it cause? —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 04:12, 10 June 2010 (UTC)

As a dry powder, it rapidly produces carbon dioxide gas when it comes into contact with any acid, such as the hydrochloric acid in your stomach. Even a few grams of sodium bicarbonate could produce several liters of carbon dioxide gas; this could be either uncomfortable or dangerous depending on how fast you could expel the gas relative to how fast it is produced. Basically, if you can't burp faster than the gas is produced you could do actual damage to your stomach. When dissolved in water, you are diluting the sodium bicarbonate to the point where it will produce carbon dioxide much slower, and thus is unlikely to cause a problem. --Jayron32 04:18, 10 June 2010 (UTC)

can it cause bleeding ulcers ? —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 04:23, 10 June 2010 (UTC)

Peptic ulcers are primarily caused by the Helicobacter pylori bacteria, so it is unlikely to cause "bleeding ulcers" under the conventional, medical definition of the term. However, if the gas pressure inside of your stomach due to the release of carbon dioxide is great enough, it could in theory cause the stomach to partially rupture, which can lead to bleeding of the stomach. So, yes, it can be accutely dangerous to consume spoonfulls of undiluted sodium bicarbonate. No, it cannot cause stomach ulcers, which are a chronic medical condition unrelated to what you eat. --Jayron32 04:30, 10 June 2010 (UTC)

I was under the impression that while most gastric ulcers contained H.p. bacteria, that it was not clear if the bacteria themselves caused the ulcer or if they just colonized it after it formed. I don't know if it has been definitively determined what precisely causes ulcers. Googlemeister (talk) 14:34, 10 June 2010 (UTC)

As mentioned in the Helicobacter pylori article (though somewhat buried) researcher Barry Marshall demonstrated that H. pylori can be the causative agent of ulcers by drinking a culture of them. Numerous subsequent studies have demonstrated that ulcers can be alleviated by treatment with antibiotics (also indicating a bacterial origin). Of course, that only shows that some ulcers are caused by H. pylori, not that all of them are. -- 174.24.195.56 (talk) 15:02, 10 June 2010 (UTC)

Most toy rockets use baking soda and vinager as a fuel to give you an idea of how dangerous consumming a spoonful of soda might be, especially on a full stomach with absolutley not room for any gas. 71.100.0.241 (talk) 12:51, 10 June 2010 (UTC)

question on cars and automated transmission...

Im a Medical Doctor so my knowledge on cars and engineering mechanics is limited so pardon me if the question is pretty infantile. however i would appreciate answers which are explanatory. question is : if we take two identical cars - say two toyota landcruisers, 6 cylinder 4 wheel drive top end model, one is manual transmission ( meaning manual gear system) and the other is automated transmission ( automatic gear change) which one would be more fuel consuming - or to put it the other way which model will consume less fuel?

most people say the automated transmission is a FUEL GUZZLER and would waste a lot of fuel but I feel in an anutomated transmission car, chances of the driver using the clutch and brakes are lesser and as a result it would actually save fuel... explain pls... —Preceding unsigned comment added by Fragrantforever (talk • contribs) 04:31, 10 June 2010 (UTC)

For the same model of car, the difference between a stickshift and an automatic transmission is small, but measurable. That is, a stickshift Hummer is unlikely to get better fuel mileage than a automatic transmission Honda Civic, but when choosing between to versions of the same model of car, the stickshift invariably gets a few better miles per gallon. See this article by Consumer Reports, which found that stickshifts got about a 2-3 mpg improvement over their automatic counterparts, and also performed better in terms of acceleration. I'll leave it to the engineers to explain why this is so, but it is undoubtedly a real effect. --Jayron32 04:41, 10 June 2010 (UTC)

Automatics are not the gas-guzzlers they once were, and the fuel efficiency of the manual depends on the driver's skill at manipulating the transmission, but in general they(automatics) are still less efficient.

It's important to note that an automatic transmission works differently than a manual one. It's not like you've got a manual transmission with a robot shifting for you, It's a different type of mechanism. So most of them do actually have less efficiency than a standard car of the same model, assuming the standard driver has a reasonable level of skill.

Nowadays, there seem to be exceptions to that once hard and fast rule, though. Check out these numbers for the 2000 RAV4 : [1][2]. If these numbers are right, then the auto is slightly more fuel efficient, especialy on the freeway. I'm not sure what causes that. APL (talk) 05:05, 10 June 2010 (UTC)

Autos always were less efficient since most of them use a torque converter instead of a clutch. This works rather like slipping the clutch all the time, and since it slips, it wastes power and therefore fuel. More modern autos can lock up the torque converter - normally in top gear - and this makes them more fuel efficient and approach the efficiency of manual transmission. My guess is that where the auto is more efficient than the manual (e.g. the RAV4 above), then this is down to the different gear ratios used - probably the auto has a higher ration "overdrive" top gear. --Phil Holmes (talk) 07:45, 10 June 2010 (UTC)

It should go without saying, but how the manual transmission vehicle is driven will also affect mileage. Consider the case of a driver travelling at constant speed. The automatic transmission will generally try to keep the vehicle in the highest reasonable gear in order to maintain the lowest engine speed and minimize fuel usage (I'm simplifying somewhat). In practice, this may mean shifting up into top (overdrive) gear even at quite moderate speeds, as long as the vehicle is not accelerating. The driver with a manual gearbox may not be quite so aggressive about upshifting (for convenience, out of absentmindedness, for fear of stalling, because they like to weave in and out of traffic and need the torque, or because they just never learned to do so). In this situation, the mileage of the automatic may well exceed that of the manual, where the manual is not being driven optimally for fuel economy. TenOfAllTrades(talk) 13:03, 10 June 2010 (UTC)

One additional factor is that a manual often (but not always) has more gears than an automatic of similar vintage. This can make it slightly more efficient also. There are even a few "automatic" transmissions these days that use the architecture of a manual, but with solenoids doing the clutching and shifting for you. These should be more efficient than a conventional automatic, but I believe right now they're found only on a few very high-end cars. Friday (talk) 14:57, 10 June 2010 (UTC)

Not anymore. The DSG is at least 6, more commonly 7 gears which is an overkill for a reasonable car with manual. As soon as the Japanese catch up ... East of Borschov (talk) 15:53, 10 June 2010 (UTC)

I'm not an engineer, but having about 20 years of observational experience I will say (for 90% of it) the difference is the number of gears. Automatics of yore had 3 (gasp!) or 4 gears, maybe one overdrive (basically a taller top gear) so when accelerating you spent a lot of time at a sub-optimal RPM. Manuals are typically always 5 well spaced gears, some 6. However; modern cars (mostly japanese and european) are making 5 or 6 speed automatic transmissions standard and on these models you are seeing the difference between the MPG rating of the manual and automatic versions almost disappear. Ultimately if you drive a modern car and if you are really soft-footed you can get a great MPG out of either kind of car. It all comes down to how much time the motor has to spend at an awkward (usually high) RPM. --144.191.148.3 (talk) 13:35, 11 June 2010 (UTC)

If you are a good driver, and you know how to shift such as to be fuel efficient you can save about 5% by driving stick - mainly because of losses through the complicated automatic transmission mechanism. If you are a terrible driver or if you simply enjoy revving the heck out of your car - then the automatic will be able to moderate that and you'll get better mileage with the automatic gearbox. However, you would be surprised at how hard it is to drive a manual gearbox in a really fuel-efficient manner...you need to keep the RPM strictly within the 1500 to 2500 range (or perhaps 2000 to 3000, depending on the type of car). I can practically guarantee, you'll notice you're going over that when accelerating in-town. To keep within that range, you'll be doing a LOT of shifting! SteveBaker (talk) 23:53, 10 June 2010 (UTC)

Thanks for all the answers...appreciated... Fragrantforever 05:10, 11 June 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)

Sapphire Question

I had asked a question relating to Blue Sapphires earlier but this is different. To cut a long story short I finally found the Blue Sapphire I was looking for and a jeweller sold me a very expensive 5 carat sapphire set in a gold ring. Is it possible I could through some experiemnts/ tests confirm it is indeed a blue Sapphire and not any other imitation blue stone? Is it possible to check if the colour is indeed naturally deep blue or wheteher it was heat treated to take this brilliant deep blue hue colour? I have read unscruplous jewellers heat the Sapphire to increase the colour from a pale blue to a brilliant deep blue. Is it possible to check if the stone was heated to improve its colour? Though these questions might sound trivial, let me tell you I have very personal and sentimental reasons for asking - to ensure it is indeed a blue Sapphire and not any other imitation blue stone and that it is not heat treated Fragrantforever 07:22, 10 June 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)

From what I could see on the article, it's pretty hard to tell (there is some mention of loss of "silk", making the stone more transparent). You more or less have to trust the certificate they gave you. You can try looking at it through a magnifying glass, but you would need to know what to look for. Did they give you a certificate? What does it say? Who's it from? Ariel. (talk) 08:47, 10 June 2010 (UTC)

What you do is to agree to buy the sapphire on condition that you may return it within (let's say) three days and get all of your money back. Then you go to a rival jeweller and state that you wish to sell this valuable Blue Sapphire. They will check it meticulously and tell you if it's a fake. If it is, you take it back, if it is not then you politely decline whatever money they offer you (unless it's way more than you paid for it!). SteveBaker (talk) 23:26, 10 June 2010 (UTC)

Not sure I agree with the entire thing here. If the second dealer you take it too is not 100% above board (and a significant % might not be), then he/she might try to take advantage of you by telling you that it is fake, or of low quality and will offer only a low amount, even if the sapphire is indeed high quality. Googlemeister (talk) 13:21, 11 June 2010 (UTC)

Thanks to Ariel and Steve for your replies, Steve your answer in particular is brilliant and yet a very easy solution to the vexing problem i face... yes I remember the jeweler telling us he would take the Sapphire back if I felt it wasnt lucky for me... so far its been lucky for us I guess... But I will follow your advice and take it to another jeweler telling them I wanna sell it... sounds like a brilliant suggestion... thanks for the answer. Fragrantforever 05:17, 11 June 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)

indoor door frames

are indoor door frames made out of solid real wood or plywood. and is it a treated wood? —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 10:33, 10 June 2010 (UTC)

If they are light, most likely they are just a plywood or particleboard box (hollow inside). --Chemicalinterest (talk) 11:18, 10 June 2010 (UTC)

Depends when the house was built. I've renovated a couple of Victorian houses in the UK, and the door and window frames were either pine or deal. Newer houses in the UK probably use pine. Can't say whether they're treated or not - what would they be treated with, and for what purpose? --TammyMoet (talk) 12:37, 10 June 2010 (UTC)

• On that last point, I assume the reference is to pressure-treated wood or some other form of wood preservation. As far as I know this sort of thing is only done for wood to be used outdoors unpainted, where it will be exposed to weather. --Anonymous, 18:09 UTC, June 10, 2010.

The question is about frames. These need to be solid timber for strength, and the thickness will depend on the weight of the door(s). They would not normally be treated, except by being seasoned, and painted.--Shantavira|^{feed me} 12:36, 10 June 2010 (UTC)

The frame would indeed be "real" wood, though there may be multiple pieces of 2x4 or whatever to get the desired thickness. I don't think they're typically painted, though, as they're (usually?) internal - they provide the structural support and not much else). The opening of the door is also surrounded ("framed" in the everyday sense, though not the carpentry sense) by decorative material that often is painted and may be made of either natural wood or any one of the several kinds of composite wood-based products on the market. This decorative material is usually made to match either the footboards/toeboards or the door itself if it's been decorated. Standard pressure-treated lumber is not suitable for interior use because of the toxins it exudes (or at least used to; I'm not up on the latest developments). Matt Deres (talk) 18:58, 10 June 2010 (UTC)

You can see new door frames on sale in the UK at Wickes and B&Q, presumably in other countries you can see them in the equivalent DIY stores and ask what they are made of. In the UK they would be solid pine (could be FSC-certified) or MDF. In France the door frame and door are sold together (a "door set") and solid pine is common there too. Itsmejudith (talk) 22:47, 10 June 2010 (UTC)

glycemic load determination

Many people complain that while glycemic load determination methods try to address factors like particle size there are a variety of methods being used and only a relatively few foods are listed for each method. Wouldn't it be better to measure glycemic load by simply showing the rate at which a particular food is oxidized, i.e., converted to water and carbon dioxide similar to the way in which the speed of the wave front is used to determine the power of an explosive? 71.100.0.241 (talk) 12:19, 10 June 2010 (UTC)

Because particle size is related to the rate of reaction. To use your explosive analogy, one pound of gunpouder contains a fixed amount of energy. If I spread it in a thin layer in a pan, it will release the same amount of energy as when I pack it closely in a pipe. But, the rates of reaction, and the velocity of the shock wave (I doubt the pan will have a shock wave) will be different. —Preceding unsigned comment added by Hacky (talk • contribs) 17:49, 10 June 2010 (UTC)

So by the same token glycemic load is not accurate unless you state whether the ingredients were blended and liquefied or eaten whole so the method preparation has to be analyzed and stated. 71.100.13.202 (talk) 20:57, 10 June 2010 (UTC)

the best it could be?

Resolved

what about the argument that a huge company like Philip Morris has no interest in having their customers die off (perhaps accounted for as "attrition" in their sales forecasts), so insofar as they have any control over the formulation, yes, their R&D would make it as addictive as legally possible (or the most they can get away with in PR terms) but also the least lethal they can -- I mean doesn't that stand to reason? Philip Morris is a Fortune 100 company, I am sure their research department doesn't just get their additives from a tire melting plant on the theory that it is cheapest, indeed the tire melting operation could even be paying them to take the waste off their hands?

Note: I started smoking because of your health effects of smoking article, so if you want to attack me, why not go straight to that source and remove the spin, if you can - and if you can't, my theory is that it isn't spin. 92.229.12.67 (talk) 13:50, 10 June 2010 (UTC)

I'm not sure what the heck you're talking about. The article clearly states that smoking is a dangerous activity, that is likely to have many different, mostly negative, impacts on your health (Including a terrifying 1-in-5 chance of lung cancer!), and will significantly reduce your estimated life expectancy.

As for your theory, it's good as far as it goes, but there are two major strikes against it. First, unfortunately the basic operation is fundamentally dangerous. You're burning plant material, and sucking the resulting smoke into your lungs. They don't have to do anything special to cigarettes to make them dangerous, it's just that smoke itself is fundamentally bad for you. Second, most efforts to remove the dangerous components from smoke (better filters, etc) also remove the most flavorful components. In fact in some cases they might be the same components. The primary main concern of the cigarette manufacturers is to make sure that existing smokers choose their brand instead of competing brands. This makes sense. If Marlboro suddenly changed their cigarettes so that they were much safer, but had a boring taste, smokers would just smoke some other brand. Then Marlboro would go out of business, and the smokers would still destroy their lungs. APL (talk) 14:29, 10 June 2010 (UTC)

Someone who started smoking because they read an article saying it ruins your health, makes you impotent, and then it kills you. Should it have mentioned it give you bad breath and makes your toes fall off or would that have encouraged you? I think that merits the slow lingering Darwin Award. Dmcq (talk) 15:17, 10 June 2010 (UTC)

I can give you a line by line analysis of what parts, probably added by someone on Tobacco's payroll, convinced me. For starters, the article is called health effects: in English the grammatical meaning of that phrase is arrived at through association with other noun + noun phrases. What is a school bag? So, anyone who is worth six figures due to their education knows that "health effects" has a positive meaning, since health is a positive word. I can give you further analysis line-by-line, but the upshot is that the article convinced me to smoke, and is still convincing to this effect. 92.229.12.67 (talk) 15:24, 10 June 2010 (UTC)

(e/c) I think what the IP is trying to say (in a somewhat awkward manner) is that a company like Phillip Morris (or for that matter like Toyota, or BP, or Dow Chemicals) sees the deaths of clients or passers-by as a financial risk to be insured against rather than a moral dilemma. The tobacco industry is far more concerned about being asked to pay for lung cancer treatment than it is about being the cause of lung cancer, and it will continue to produce cigarettes so long as it can shift the financial burden of lawsuits and medical care (and etc) off onto the customer. which it does very effectively - why do you think the US government taxes the sale of cigarettes to apply to medical funds - which comes straight out of the consumers' pockets without affecting the corporations' bottom lines - rather than forcing the corporations to set up a medical trust - which would come out of corporate profits, and might affect shareholder interest.

According to classical macroeconomics, whether the tax is on the consumer's side or the supplier's side doesn't affect who is impacted the most -- only the elasticity of supply/demand. Unfortunately, the elasticity situation does minimal overall effect on the supplier at the expense of the consumer. (See tax incidence) John Riemann Soong (talk) 15:55, 10 June 2010 (UTC)

as to why the IP thought that our article was a good reason to start smoking... agree with the Darwin Awards suggestion, except that slow death by tobacco will allow him to live well past breeding age, and so his choice may not benefit the human genome. C'est la vie. --Ludwigs2 15:37, 10 June 2010 (UTC)

The ghoul in me says the original argument is flawed in that it supposes the current levels are substantially above what's necessary and sufficient to be likely addictive--that there really is a "therapeutic" window being exceeded. Even more ghoulish, they really do need to keep these levels as low as possible because "too much" toxin leads to too rapid a death...not living for many years of habitual smoking makes the product less profitable. DMacks (talk) 15:47, 10 June 2010 (UTC)

If you have specific concerns about an article, please discuss them on that article's talk page; the Wikipedia Reference Desk isn't really the appropriate place. Moreover, nowhere on Wikipedia is an appropriate place for soapboxing and general commentary; you can use your Facebook page or Twitter account for that. TenOfAllTrades(talk) 15:46, 10 June 2010 (UTC)

I particularly like 92.229's ham-fisted attempt at guilting us into doing ... something. Oh yes. "Because I detected some errors in your Wikipedia article, (Probably added by someone trying to introduce misinformation.) I have decided on a course of action that has very high likelihood of killing me." Very convincing narrative right there. It reminds me of the time I drove 185mph in a 35 zone because someone had used spray paint to graffiti the speed limit sign.

I'd better go turn the article into a ridiculous, cartoonish, hack-job so that someone like 92.229 doesn't start smoking because we didn't exaggerate its deadly effects enough!!!

Seriously, how old are you? Ten? APL (talk) 16:08, 10 June 2010 (UTC)

Trolls are ageless. Comet Tuttle (talk) 20:46, 10 June 2010 (UTC)

Sorry, you people are misunderstanding why I say Philip Morris research would try to reduce the impact of death as far as they can: it is because the estates of deceased don't continue to buy cigarettes on behalf of the dearly departed. I thought it would be obvious. If I have dues-paying members of my cult, and my cult is a fortune 100 company, then why would I want any of them to die? Obviously I don't. 92.229.12.67 (talk) 16:04, 10 June 2010 (UTC)

We're not stupid. We understand your point. Now understand our point : You Are Wrong. There is no way to make cigs safer while keeping them desirable. It is the smoke itself which is dangerous. They could construct a cig so that less smoke goes into your lungs, but who the heck would buy that?

It'd be like McDonalds replacing all their unhealthy food with green salad. Sure their customers would live longer, but they wouldn't have any customers! Everyone would just go to Burger King. APL (talk) 16:08, 10 June 2010 (UTC)

However, you may be interested in Cigarette filter, and Light cigarettes which are efforts to make cigarettes safer, just like you say. Filtered cigarettes seem to have caught on, but most people say that lights just don't have the flavor they're looking for.

I'm not a smoker so I couldn't say for sure.

Doesn't matter though, research has shown that the health benefits of switching to "Lights" was almost worthless. In the US they're not even allowed to describe them that way anymore. APL (talk) 16:17, 10 June 2010 (UTC)

In the US much attention was made of the government decision to allow the FDA to regulate tobacco and health claims made [3]. This [4] (subscription required) for example explains some of the problems developing 'healthier' cigarettes, for example the problem with smoking machines. Nil Einne (talk) 17:46, 10 June 2010 (UTC)

As regards APL's claim that "there is no way to make cigs safer while keeping them desirable" — that is not clear to me at all. Actually I think it may well already have been done, with e-cigarettes, which give you the nicotine without the "tar".

The current hullaballoo about them seems to be related to avoiding creating the perception that e-cigs are safe. I'm sure they're not safe. But they may very well be safer. LET ME SAY VERY CLEARLY that I am not saying they are safer — it's out of my area of expertise. But to my naive eye it appears very plausible that they might be. And if so, I think it could be a terrible mistake to try to ban them, or otherwise discourage them from the market. --Trovatore (talk) 00:35, 11 June 2010 (UTC)

Most large corporations care nothing for public health, especially not MacDonald's. ExxonMobil is another example as it promotes climate change denial. ~AH1^(TCU) 02:54, 11 June 2010 (UTC)

By indentation, that looks like a response to me, but it doesn't appear to be responsive to anything I said. --Trovatore (talk) 02:55, 11 June 2010 (UTC)

E-cigs may or may not be safer, but they're not cigarettes. Burning some tobacco and then inhaling the smoke is pretty much the quintessential cigarette experience. What you've got here is a nicotine delivery mechanism, like a patch or a chewing gum. It's the difference between a cup of coffee and a caffeine pill!APL (talk) 03:04, 11 June 2010 (UTC)

Hmm, no, it's the difference between a cup of coffee and a hot caffeinated beverage. The e-cig still delivers something recognizably smoke-like. Or at least so I'm led to understand (I don't smoke). --Trovatore (talk) 03:10, 11 June 2010 (UTC)

I think it's more like the difference between a cup of coffee and a caffeine pill dissolved in hot water. My chain-smoking friend tried to switch to an e-cig, and said it didn't taste like a cigarette. He also had difficulty controlling the dose, and kept either not getting enough (which didn't satisfy) or getting too much at once (which left him light-headed). He switched back to cigs after a couple of weeks. 86.164.69.239 (talk) 11:36, 11 June 2010 (UTC)

Anyway, the spirit of the question was that the cigs currently on the shelf must be safe because tobacco companies don't want to kill off their customers. This is false. The tobacco companies are far more concerned about losing customers to competing brands than to the Grim Reaper. APL (talk) 14:15, 11 June 2010 (UTC)

OP here. Thank you for the clear answer, I've put a resolved tag on. For reference, the exact fallacy in my thinking had been addressed with the line "There is no way to make cigs safer while keeping them desirable. It is the smoke itself which is dangerous." So, my logic IS right, but has no applicability: yes, cigarette companies have an incentive to add a magic additive that has no affect on taste but reduces mortality. However, there doesn't (in your estimation) exist any such magic additive. I am going to reduce my smoking to 1/18th of a normal smoking level, to get to the same risk I would have if I regularly drove: I don't drive at all. 92.224.205.209 (talk) 14:22, 11 June 2010 (UTC)

nothingness

Is there a theory that states why it is impossible for nothing to exist, ether mater or energy or space? 71.100.0.241 (talk) 16:22, 10 June 2010 (UTC)

Cogito ergo sum Staecker (talk) 16:43, 10 June 2010 (UTC)

Unfortunately, that theory includes the dimension of time, which would require the thinker to live forever to be valid. 71.100.0.241 (talk) 17:10, 10 June 2010 (UTC)

I don't see any mention of time. Does existing in only a limited region of spacetime not count as existing? --Tango (talk) 17:12, 10 June 2010 (UTC)

I did not include reference to time in the question so for clarity I will include it here. 71.100.0.241 (talk) 17:21, 10 June 2010 (UTC)

There couldn't be any such theory, because any theory must start with axioms. An axiom would only be useful here if it was more basic than the fact that something exists, and what could be more basic than that? However, you might be interested in reading about the anthropic principle in relation to this. Looie496 (talk) 17:06, 10 June 2010 (UTC)

Do you mean nothing at all anywhere? ie. there being no universe? There are plenty of theories about why the universe exists, but none are really anything more than guesses. --Tango (talk) 17:12, 10 June 2010 (UTC)

Yes. 71.100.0.241 (talk) 17:17, 10 June 2010 (UTC)

If matter, energy and space did not exist, who or what could have asked the question? 87.81.230.195 (talk) 17:23, 10 June 2010 (UTC)

it never fails that when a question is asked on the Wikipedia that at least one person will respond who has not read or understood it. 71.100.0.241 (talk) 17:29, 10 June 2010 (UTC)

Perhaps, then, you could kindly elucidate ". . . ether mater . . ." for us :-). 87.81.230.195 (talk) 00:13, 11 June 2010 (UTC)

This is a philosophical question about metaphysical nihilism, not a scientific question. Scientific experiments are conducted under the assumption that observation is somehow meaningful, and it's hard to imagine observation being meaningful without at least subject to observe and an object to be observed. Paul (Stansifer) 17:47, 10 June 2010 (UTC)

You are thinking, as everyone else that because the universe exists the impossibility of nothingness can naturally be assumed. 71.100.0.241 (talk) 19:12, 10 June 2010 (UTC)

It's not an assumption, it's a fact. The universe exists, therefore the probability of the universe existing is 100%. Probability is always conditional on the information we have. Once you have definite information about something, its probability becomes 100%. --Tango (talk) 21:12, 10 June 2010 (UTC)

The fact that things exist is a very flimsy theory of the impossibility of nothingness. People remember walking in and out of the World Trade Center and some considered doing so not just theory but proof of the impossibility of nothingness in regard to the existence of the Would Trade Center. For some it continues to exist in pictures and memory but their theory of the impossibility of nothingness in regard to the Twin Towers no longer exists, especially since they were not rebuilt and most likely will not be rebuilt. 71.100.13.202 (talk) 16:46, 11 June 2010 (UTC)

Observations of the World Trade Center are proof that the WTC definitely existed at the time it was observed. Observations of the universe now are proof that the universe definitely exists now. The universe existing now and nothing existing now are mutually exclusive options, so it is also proof that there is no nothingness now. --Tango (talk) 19:15, 11 June 2010 (UTC)

It's certainly a fact that something exists. The question is, is it a necessary truth, or a contingent one? Your response doesn't address that point at all.

It's true that this is not a scientific question in a narrow sense of the word. But there isn't any philosophy refdesk, and it's closer to science than anything else. Cosmologists do worry about things not that much more concrete than this. --Trovatore (talk) 21:45, 10 June 2010 (UTC)

I wasn't making an argument for the existence of anything (though I believe things do exist -- I've seen some of them!); I was just saying that science isn't meaningful unless stuff exists. Therefore, whether anything exists is not a question science has anything to say about. Paul (Stansifer) 21:28, 10 June 2010 (UTC)

Here's how I like to think about it - take a universe where nothing exists. Now since nothing exists everywhere, the universe is completely symmetric as a sphere, thus it has a shape and consequent physical laws governing it (this is a big important consequence of Noether's Theorem). Our current scientific theory of an empty universe is instead bound by quantum mechanics. A QM universe has a dynamic equilibrium - being static and void is "more something" than being in constant turmoil as nature tries to keep any harmony from existing, this being understood a little in the Heisenberg Uncertainty Principle, where being static does not exist (you are always blurry).

So a universe in its most simple form is in utter turmoil, a churning soup of micro-energy (and in some theories, micro-wormholes). The Inflation (cosmology) scenario is that from this quantum-mechanical turmoil, there is a probability that a "metastable" state called a false vacuum appears spontaneously, with some sort of random set of physical dimensions and constants, and expands rapidly. This is the Big Bang, the beginning of our universe. SamuelRiv (talk) 17:47, 10 June 2010 (UTC)

In order for "nothing" to exist, you must have some "something" to compare it to. For example, dark is the absence of light. So "dark" is a "nothing". But suppose I claim that right now it is "foo", because of the absence of "bar". So my "foo" is a "nothing" - but actually it's not. Since "bar" does not exist, there is no absence of it called "foo". In the same way the absence of a "something" (called "nothing") can not exist without the "something". As a side note, in Jewish philosophy the very first thing God created was nothing. i.e. the concept of nothing, also called a void. Ariel. (talk) 21:09, 10 June 2010 (UTC)

This question is addressed quite well in a book called God: The Failed Hypothesis. Stenger scientifically addresses not only why there is something instead of nothing, but also the appearance of order from chaos in the universe and the issues that raises regarding apparent decrease in entropy. Vespine (talk) 23:12, 10 June 2010 (UTC)

All classical physics theory takes as axiomatic that no matter, energy or space is empty of its laws. For example, Newton's law of universal gravitation denies that even the remotest space is void of gravitational influence. Religious belief systems that predicate an omnipotent Creator must conclude that His influence pervades all that can ever be (because He wills it so). However relativistic physics provides a conception of a nothingness being that which is beyond an Event horizon. Cuddlyable3 (talk) 23:36, 10 June 2010 (UTC)

I'm not sure that is correct. For example the constancy of the speed of light still exists, even beyond the event horizon. All the various laws still exist there, there is just no information/matter there. But the "basic framework" is everywhere. Just because I am not aware of something (or even if I can not) - doesn't meant it doesn't exist. Ariel. (talk) 23:49, 10 June 2010 (UTC)

Now you're going from physics to ontology. I would disagree, for example, is the speed of light in a Gravitational singularity still equal to c? I could be mistaken but I thought that time and space formed at the big bang, so even though it might be impossible to know what was before the big bang, one theory is that there was nothing. Vespine (talk) 00:15, 11 June 2010 (UTC)

To someone falling into a singularity everything looks normal, so yes, c is the same. And anyway, changing c changes the energy content of matter (e=mc2), so you most definitely can not change c. Ariel. (talk) 00:27, 11 June 2010 (UTC)

It doesn't make sense (within our science) to talk about conditions "in" a singularity. A singularity is a point where everything breaks down - mathematically we essentially treat the point as if it doesn't exist. --Tango (talk) 00:51, 11 June 2010 (UTC)

See reality, nothing, and variable speed of light. ~AH1^(TCU) 02:50, 11 June 2010 (UTC)

you might also check out nondualism. --Ludwigs2 04:10, 11 June 2010 (UTC)

Returning to the original question - "Can nothing exist ?" - in physics the answer is "no", because of zero-point energy; in mathematics the answer is "yes", the empty set; in philosophy the answer depends on what you mean by "nothing" and "exist" - take n philosophers and you will get n+1 answers. Gandalf61 (talk) 09:32, 11 June 2010 (UTC)

The original question is not "...can nothing exist...?" The original question is whether of not there is a theory as to the impossibility of nothingness. Quite distinct and separate questions. 71.100.13.202 (talk) 17:00, 11 June 2010 (UTC)

This is an entirely reasonable question. Until recently, there was nothing but speculation about the fate of this universe; now, its likeliest fate is that it will continue to "exist" forever, eventually reaching a state of overwhelming emptiness (lack of density), but the possibility of it one day ceasing to "exist" was still an arguable position only a few decades ago. Meanwhile, as far as we know, NOTHING EXISTED fourteen bllion years ago (though one interpretation of space-time is that it is nonsensical to refer to "time" before the big bang). The question is highly relevant in terms of (at least) cosmology (whether "nothing" is a possible state is a crucial question in regard to the pre-big-bang multiverse ... IF THERE IS ONE!). 63.17.62.133 (talk) 10:18, 11 June 2010 (UTC)

Can we have more Lay explanations for phenomena under the physics heading?

I am a poorly educated person of middling intelligence, with an interest in physics of all sort, but no head for calculus or advanced mathematics.

I would like to understand more about particle physics, but many of the explanations on Wikipedia are too complex.

I suppose what I'm asking is can we have more articles where things are explained as if to a four year old?

When I leanred about the strong, weak and electromagnetic forces, I had them explained to me using the analogy of the four forces that act on an airplane: lift, drag, thrust and weight; and this explanation, while not technically accurate, at least gave me a sense of how the forces interacted.

When I wanted to learn about magnetism, I was directed to ferrous metals, which went on and on about fermions and atomic spin and did little to explain to me what makes a metal magnetic in a practical way an unintelligent person can understand.

Thank you all for your time and I apologise if my question was inane or misplaced. AWanderingFlame (talk) 17:09, 10 June 2010 (UTC)

I don't see how that analogy to an aeroplane is at all useful. There are no connections between the two. It would be great if we could explain all these subjects to everyone, but some things are just too technical to be understood without at least some of the background knowledge. You can come up with poor analogies that trick people into thinking they understand it, but I don't really see the point of that. --Tango (talk) 17:16, 10 June 2010 (UTC)

You have a valid point, but the fact is that Wikipedia articles are written by whoever wants to write them, and explaining technical concepts in nontechnical language is the most difficult type of science writing. Whether people who can do it choose to devote their time to Wikipedia is a matter of luck. Looie496 (talk) 17:23, 10 June 2010 (UTC)

• I recommend the website www.howstuffworks.com. Their mission is to provide simple but accurate explanations for all sorts of science and technology questions. (It's basically a web version of the Discovery Channel, which makes sense since they're both owned by the same media company.) --M@rēino 18:05, 10 June 2010 (UTC)

The question is not at all inane or misplaced; we have many, many articles that were written with a disregard for the layman. As Tango writes, it's sometimes impossible to explain sufficiently advanced topics to the layman; but I think more often it's a lack of interest on the part of the editors who are inclined to work on these articles. (It's sometimes a hard task, surely.) One suggestion I've seen on the Reference Desk here in the past is that you check the Simple English Wikipedia; here is their article on particle physics; but the objective of "Simple" is to be the encyclopedia for those with limited English-language ability, not to be the encyclopedia with simplified explanations of everything. Comet Tuttle (talk) 19:05, 10 June 2010 (UTC)

The airplane analogy is not "technically inaccurate" - it is totally and entirely wrong. It is unfortunate that somebody would use the analogy of lift and drag to describe the fundamental forces - they have only served to confuse you and provide you with incorrect information. The four fundamental forces are fundamentally different types of interactions, hence their name. See fundamental interaction. Yes, it is complicated - these things are not very intuitive. If you're looking for a qualitative introduction to the Standard Model, maybe read the overview section at Standard Model - this is much more useful than trying to understand particle physics in terms of invalid comparisons to every-day scenarios. Nimur (talk) 19:45, 10 June 2010 (UTC)

The worst are articles that are just a wall of math without a single one of the variables being defined! If you already know the material, you know what those variables are. But if you know the material you don't need the article. If you need the article you can't understand it. The articles on gauge theory were ones I noticed recently. Ariel. (talk) 21:13, 10 June 2010 (UTC)

Wikipedia has a number of introductory articles, dedicated to providing a gentle introduction to complex subjects. See WP:List of Introductory Articles. Dolphin (t) 22:55, 10 June 2010 (UTC)

It is certainly true that many of our articles on science and math subjects are written at an unnecessarily high level. I think many editors are aware of this problem and there are people actively working to improve this situation. However, some subjects (and "How do magnets work?" is certainly one of them) are simply not explicable other than by reverting to complicated explanations and math. If everything in the universe could be understood easily by the layman - then we wouldn't need physicists...and if everyone could mend broken pipes - then we wouldn't need plumbers...since pretty much everyone can write, we don't need scribes. It's just a matter of degree. SteveBaker (talk) 23:13, 10 June 2010 (UTC)

Not entirely true, maybe people who can fix pipes just don't want to be bothered with it. Just about everyone could mow their lawn, but there are still plenty of yardwork businesses. That is called the service economy. Now we just need to find someone who wants to fill the service demand for interpreting the dense science, math and engineering articles we have that are mostly equations. Googlemeister (talk) 13:14, 11 June 2010 (UTC)

I don't believe Wikipedia has any article that explains as if to a four year old, though some of the pictures might capture a child's attention. WP:NOTCENSORED implies that Wikipedia is not an encyclopedia for children. Cuddlyable3 (talk) 23:46, 10 June 2010 (UTC)

I fail to see how WP:NOTCENSORED implies that Wikipedia is not for children. It probably implies that it is not for certain kinds of Americans.

I do think that the OP has a good point though. And I think the problem is routed deeper. I believe, I could give a pretty good explanation of how magnetism works that is essentially correct as a first approximation and understandable to the OP, but I would never get it in a Wikipedia article. The problem is that my explanation is utterly unverifiable, since by necessity it would be 'wrong' in all the details. Pretty much any explanation that hinges on an analogy (like the aeroplane forces or that pretty picture of electrons orbiting an atomic nucleus) are going to be fundamentally wrong by modern understanding of physics. Is an encyclopedia simply the wrong medium for generally understandable (i.e. simplified) explanations? How do printed encyclopedias solve the problem? BTW, a good attempt at explaining science at a general audience is Bill Brysons "A short history of nearly everything". Hundreds of errors in the details, but still correct in essence and an enjoyable read.213.160.108.26 (talk) 23:42, 11 June 2010 (UTC)

Do fish get mardy?

if you poke them or something? —Preceding unsigned comment added by 86.128.193.83 (talk) 18:13, 10 June 2010 (UTC)

Assuming this is not a joke at the expense of Mr. Mardy Fish, we have a couple of articles that are sort of related. Pain in fish discusses whether fish do feel pain; one scientist is quoted as doubting that fish really feel pain in the way we do, as fish lack a neocortex. This would seem to reduce the likelihood that fish get irritable or miserable. Related is Emotion in animals, which does have a "Fish" section, though its only claims are about different fish of the same species exhibiting different "personalities" — actually, different amounts of risk taking, being "sociable", and having different eating preferences. It'll always be hard to evaluate whether animals get "mardy" because of course they can't tell us. Comet Tuttle (talk) 18:59, 10 June 2010 (UTC)

They might if you try to trawl them. Richard Avery (talk) 16:08, 11 June 2010 (UTC)

Chloroform

http://www.mangafox.com/manga/pok_mon_adventures/v32/c358/5.html

Does chloroform really work that fast? (At least, I assume that that's chloroform in the rag/handkerchief.) --75.25.103.109 (talk) 22:20, 10 June 2010 (UTC)

No it doesn't (though our chloroform article doesn't discuss the question). According to Stratmann, Linda (2003). Chloroform: The Quest for Oblivion. Sutton. ISBN 0 7509 3099 3., p.120: "The dramatic evidence of a victim was often preferred to the sober oxpertise of a medical man, who knew that up to five minutes were required to anaesthetise even a willing subject." --ColinFine (talk) 22:49, 13 June 2010 (UTC)

June 11

hollow core door

is the vanear of a hollow core door made from solid real wood or plywood or MDF ? —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 02:36, 11 June 2010 (UTC)

It could be real wood or it could be some sort of plastic material. There's lots of different types of construction. By definition, a veneer is usually a singly ply, so something like MDF (basically high quality particle board) wouldn't hold up, and ply wood is basically multiple veneers pasted together. But there are real wood veneers, and there are plastic veneers made to look like wood to various degrees. --Jayron32 03:06, 11 June 2010 (UTC)

its not plastic its some kind of wood. how do i tell if its MDF or plywood or solid real wood —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 03:19, 11 June 2010 (UTC)

If it's a hollow core door, it will not be "real" wood in the sense that it's a series of sliced pieces of wood in a single layer. Rather, it can be plywood, MDF or hardboard. Most flush hollow-core doors are faced with plywood with Philippine mahogany, or "lauan" as the face sheet. It will show a slight texture and grain . MDF or hardboard will be smooth and grainless, with hardboard being, well, harder and slicker. The interior of the door usually contains a cardboard homeycomb spacer. Acroterion _(talk) 03:28, 11 June 2010 (UTC)

so if it is a single ply plywood does it have formaldehyde resin on it ? —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 04:02, 11 June 2010 (UTC)

There are no single-ply plywoods - plywood has at least three plies. That said, it might have formaldehyde resin in it,depending on when and where it was made. Recent plywoods in North America usually don't use formaldehyde resins for interior applications. Acroterion _(talk) 13:51, 11 June 2010 (UTC)

Katla eruption VEI

Hi. If Katla were to erupt in the near future, what scale would it fit on the Volcanic Explosivity Index? Would the effect of a subglacial eruption increase its explosivity? Also, would it release more ash than Eyjafjallajokull did? Thanks. ~AH1^(TCU) 02:43, 11 June 2010 (UTC)

It is literally 100% completely impossible to predict. Scientists have been able, for 25 years or so, to roughly predict when some volcanoes will erupt to within a few weeks, once they start showing signs of activity. However, there is no reliable way to predict the size of an eruption before it happens, especially for volcanoes which are not currently active.. We can look at the relative sizes of past eruptions, but for a completely inactive volcano, it is someone less accurate to predict than throwing darts at a board blindfolded. Indeed, recent eruptions of Katla have been so small as to be barely detectable, according to the article and its sources. --Jayron32 03:02, 11 June 2010 (UTC)

Sure they are impossible to predict with any certainty, but I think that they are 100% impossible to predict is a little strong of an argument. I'm sure a thorough geologic and seismographical study of the area could at least make some conclusions about how it would erupt (VEI potential, mode of eruption, etc.); someone correct me if I'm wrong though. -RunningOnBrains^(talk) 04:40, 11 June 2010 (UTC)

I see your motivation, as listed in the article, being that Katla is extremely active and Icelandic authorities are already preparing for a sister eruption. In that case, I'd suggest that they're preparing for something similar to, say, the 1918 eruption and other historical eruptions, which are detailed in one of the citations for the main article. See the left-hand menu for a list of further information on historical Katla eruptions. SamuelRiv (talk) 05:21, 11 June 2010 (UTC)

Energy numbers to open a black hole

I'm not a physicist by any means, so I might be completely wrong here, but I know if enough energy was collected, a black hole could be created (a lot of time travel stuff I've heard talks about this). I recall a friend of mine once said that they would at least need the energy inside the sun to achieve this sort of thing. But how much energy would you need to actually accomplish this? If I had a giant battery the size of a planet, how many watts or horse power or some other measurement would I need to fill it to do this?  ?EVAUNIT^{神になった人間} 05:16, 11 June 2010 (UTC)

Hi there, this is a terrific exercise for a student. You may have heard of escape velocity, which the moon rockets had to exceed to break free of Earth's pull. There is something called the Chandrasekhar limit which determines the mass and radius of a black hole after its formation. That is, when a star explodes, if it's remaining core is way too heavy (about 3 times the mass of the sun), then it collapses into a black hole. A black hole is so dense that light cannot escape.

Now here's where we get to do real physics. In the escape velocity article, we see that the velocity is ${\sqrt {2GM/r}}$, where G is the gravitational constant (the strength of gravity in human units), and M and r are the mass and radius of the object we're escaping from.

What you want is the energy density needed to make a black hole. Density is just mass over volume, energy density is energy over volume, and in the world of outer space, we can always say E=mc^2 to tie them together. For a black hole, the "blackness" starts where light can't escape - that is, where the escape velocity = c, the speed of light, so let's rearrange the escape velocity equation to solve in terms of energy (mass*c^2): $E=rc^{4}/2G$ and $e_{density}=3c^{4}/(8\pi Gr^{2})$. The energy density is just energy divided by the volume of a sphere, 4/3 pi r^3.

Almost done now. We want to create an extremely small black hole with a usable amount of energy. Note that we'd need a lot less energy density to make a big black hole, but a lot more energy itself to make it big. We want to find a nice stable point in there, and unfortunately not a whole lot of Earthly machinery can reach that point. We can create a lot of energy but it needs too much time - we can't cram it all in there. Big colliders like the LHC are able to pack energy into extremely small spaces by colliding beams of particles at each other. The energy level in the impressive-sounding TERA-electron-volt collider is actually comparable to that of a bug accidentally flying into a window, and so plugging that into the equation for energy, we see the size (radius) of the black holes they'd like to obtain: r = 10^-39 meters. So that's a wee bit impossible (see Planck length), but the nice thing about quantum mechanics is that on those scales, impossible things always have a chance of happening. Anyway, you now have the numbers to plug in to see how much energy you need and how much you need in one place at one time (density) to have a similar possibility of creating a black hole as the pride of physics, the LHC. Does it help? Probably not. Is it neato? You betcha! SamuelRiv (talk) 06:03, 11 June 2010 (UTC)

Oh, actually, I can answer your original question without going through the last steps above. Take that first equation for energy. Power is energy per time (like watts are joules-per-second), and on these scales we can make a neat little guesstimate that the speed needed to make the hole is the speed of light (makes sense), so time = radius divided by c. Therefore, we take energy over radius*c, and get $P=c^{5}/2G$, which is a constant so P = 2.5 * 10^18 W. That's 2.5 billion billion watts, or 3.3 million billion horsepower. That's a lot of horses! SamuelRiv (talk) 06:18, 11 June 2010 (UTC)

SamuelRiv, what you wrote makes little sense to me. It's well known that you get the Schwarzschild radius if you set the Newtonian escape velocity equal to c, but it makes no sense theoretically to do that, so it doesn't seem like a very good exercise. You can combine c and G to get a quantity with units of power, but the relationship to making black holes is unclear to me. (Incidentally, c⁵/2G = 1.8×10⁵² W.) The people who talked about making black holes at the LHC were assuming large extra dimensions, which would make calculations involving G meaningless in that context (and the whole thing is wildly implausible anyway).

To the original poster: I think you're confusing science fiction with reality. Realistically, we can't make black holes. Unrealistically, I suppose the energy required would be the energy of the black hole, and black holes can have any energy... -- BenRG (talk) 21:01, 11 June 2010 (UTC)

Oh come onnnn Ben, using escape velocity is a common exercise for this kind of thing and gives a back-of-the-envelope guesstimate (a word that I used right in the beginning). And... black holes can't have any energy? I mean, my GR isn't great, but there is an equivalence to how mass and energy change the metric. SamuelRiv (talk) 07:50, 12 June 2010 (UTC)

BenRG's point is that yes, there is a relationship between mass and energy, and since there is no minimum mass necessary to form a black hole than there is also no minimum requirement of energy to form a black hole.

I also second his point that your answers weren't very helpfull.

174.58.105.234 (talk) 21:47, 12 June 2010 (UTC)

The problem here is not the energy but rather how to compress matter or concentrate energy to within its Schwarzschild radius. So, if you have a 10 km diameter asteroid, then how are you going to compress it to its Schwarzschild radius of about 10^(-12) meters. The energy contained in the asteroid comes free of charge, just pick one up. Count Iblis (talk) 01:01, 13 June 2010 (UTC)

if someone is scared into not riding in automobiles OR scared into not smoking, which would improve their mortality more?

So here is a scenario where someone is both a light smoker and an regular car driver/passenger: if they could be scared, by looking at car accident OR tobacco-related illness statistics, into either TOTALLY refusing to step into a car anymore (instead living locally, riding the metro, trains, etc) OR totally quitting the light smoking, respectively, then which one would improve their mortality rate more? We are talking about the average everyman, and I don't have an answer or am not pushing an agenda: I would just like to know how the two mortality rates compare. Thank you. 92.224.207.140 (talk) 09:00, 11 June 2010 (UTC)

I did a bit of fishing around for statistics. Obviously it depends where you live, but in the USA, for instance, it seems that in 2003-2004 the death rate in car accidents was about 14.75 per 100,000 head of population [5] whereas death from smoking-related illness ran at 263 per 100,000 [6]. This is a very crude comparison and doesn't take into account, for example, deaths among passive smokers or pedestrians hit by cars, which are still a risk for those who have themselves given up car travel or smoking. However, it would appear that stopping smoking is a more dramatic risk-reduction strategy, on paper anyway. Karenjc 11:27, 11 June 2010 (UTC)

If you stop driving in cars, you'll probably still have to get yourself to and from places. So you'll switch to riding the bus, the subway, a bike, walking, etc. All of these carry different degrees of risk. (I imagine that in an american city riding the subway is basically 100% safe, while biking can be quite dangerous, but biking is a lot safer in most European cities.) These risks would be very hard to estimate and would vary dramatically based on the specific setting. Quitting smoking doesn't involve "switching" to other risky behavior (unless you start overeating or drinking or etc). So this'll make it even more beneficial to stop smoking. Staecker (talk) 11:57, 11 June 2010 (UTC)

Your personal driving risk will also depend on the number of miles you drive, and where you are driving. Someone who drives 4 miles, once a week is going to be in a lot fewer accidents then your sterotypical rural salesman who might drive 500+ miles a week. The same thing can be said with smoking. Someone who smokes 4 packs a day is going to have a higher risk level then someone who smokes 1 cigar every night. Googlemeister (talk) 13:07, 11 June 2010 (UTC)

Infra-terrestrial species

Lets first start with what I mean by 'infra-terrestrial'

An 'infra-terrestrial' species, is :

• An inteligent non human-species (although the inteligence need not be comparable) that has developed complex social patterns (such as worker specialisation. ) within it's own species and it interaction with the wider ecosystem.

Which species on earth could qualify for 'infra-terrestrial' status, or do I need to provide a better definition?

Sfan00 IMG (talk) 09:05, 11 June 2010 (UTC)

Eusociality mentions ants, bees, wasps, termites naked mole rats and Damaraland mole rats. Staecker (talk) 12:01, 11 June 2010 (UTC)

It all depends on definitions. You could include, for example, lions. They are pretty smart, they live in complex social groups (prides) and have a division of labor when it comes to hunting - which is an interaction with their wider ecosystem. Rockpocket 13:14, 11 June 2010 (UTC)

Well, it's going to depend on what you mean by "intelligent". Dolphins are probably your best bet - they are generally considered to be one of (if not the) most intelligent non-human species and they live in very complex social groups each with their own language and culture. --Tango (talk) 19:34, 11 June 2010 (UTC)

Meerkats have pretty clear specialization of roles in their 'mobs' - sentries, child-care workers, tutors, foragers, etc. SteveBaker (talk) 15:56, 12 June 2010 (UTC)

Euscociality, Thanks , I knew there must be a term for it... The question was prompted by someone asking about SETI a couple of days ago. I wondered what the 'Aliens' already on earth might be  :) Sfan00 IMG (talk) 20:46, 11 June 2010 (UTC)

Gyromagnetic ratio of mesons

Hello all. Would anybody know where I can find data on gyromagnetic ratios/magnetic moments/g-factors of mesons? I find everything about nucleons, electrons and muons, but that's about where it stops. Even the Particle Data Groups is silent about it. Or is there any reason why it is not possible to measure/define this? MuDavid (talk) 09:12, 11 June 2010 (UTC)

Sentience/consciousness

Besides humans, which animals are sentient/conscious? --76.77.139.243 (talk) 12:59, 11 June 2010 (UTC)

I think this question pivots on how consciousness is defined. Bus stop (talk) 13:04, 11 June 2010 (UTC)

How do you know that humans are sentient/conscious? You know that you are, but I don't know that you are (cogito ergo sum). Would a sentient race massacre their own kind for no reason other than they are different, or pump poison into the planet that supprots them, or build weapons that could kill billions of ppl? 76.230.7.123 (talk) 13:06, 11 June 2010 (UTC)

Sentience#Animal rights and sentience and the links therein may give you some idea on the different opinions out there. Rockpocket 13:09, 11 June 2010 (UTC)

We don't have a good scientific test for Sentience. However, "Self Awareness" is usually thought to be a requirement of sentience. So you might want to check out Mirror Test, which is the best test for Self Awareness we've got. (However it is far from perfect.)

Humans, Elephants, Bottlenose dolphins, Great Apes, and possibly magpies and Orcas all pass the Mirror Test APL (talk) 14:31, 11 June 2010 (UTC)

That's mirror test. Interesting/thought-provoking aspects of this test are that human babies under about 18 months of age fail it, whereas pigeons can be trained to pass it. Gandalf61 (talk) 14:45, 11 June 2010 (UTC)

Yes that is interesting, Pigeons seem to be good at those sorts of visual processing games. I've heard of experiments where they're used to visually inspect manufactured items for quality control purposes. And they can be trained to pilot missiles at enemy ships!

I wonder if all birds can do that sort of thing, or whether it has to do with pigeons' extraordinary homing ability. APL (talk) 15:14, 11 June 2010 (UTC)

Pigeons have to be trained to pass it. The test of sentience is whether an animal can pass the mirror test without training. --76.77.139.243 (talk) 15:57, 11 June 2010 (UTC)

Of course. To prove 'self awareness' it has to be intuitive. But it's still interesting that pidgeons can be trained to pass. APL (talk) 16:00, 11 June 2010 (UTC)

Indeed. If pigeons can be trained to pass the mirror test, whereas sentience is usually assumed to be innate, then it calls into question whether the mirror test is actually testing sentience. It's like the question of whether IQ tests actually test intelligence or simply test aptitude at passing IQ tests. Gandalf61 (talk) 16:04, 11 June 2010 (UTC)

You can train most animals to do just about anything in their physical capacity, similarly to Chinese room. The test of sentience would be whether you can do the task successfully without preparation of any kind; the same is true of IQ tests and intelligence. --76.77.139.243 (talk) 16:14, 11 June 2010 (UTC)

But, in that case, are toddlers self-aware? They've spent 18 months being casually trained ("Who's that in the mirror? Can you see Daddy? And Mummy? And Billy?") until the point they start responding as we expect. Is that really intuitive? 86.164.69.239 (talk) 22:06, 11 June 2010 (UTC)

Toddlers are probably not self-aware. They fail other cognitive tests, so why not tests for self-awareness? But you seem to be asking if they grow up to be self aware. Yes, because not all human being grow up around mirrors, but adults can figure out how they work without too much trouble. Because humans have an understanding that we ourselves are a human being living in the world, just like everyone else. As opposed to, say, a dog, which might have an understanding what a dog is, but doesn't comprehend the idea of a self, so it doesn't even understand the possibility that he himself might also be a dog.

Training something to specifically pass the test is much easier. The pigeon doesn't have to understand that it is a pigeon, or that it is seeing its own reflection. You just have to teach it that if the bird in the mirror has a spot on its beak, you perform some pre-defined action. You could probably train it just as well with pre-recorded videos of a baboon. Teaching a pigeon to pass the mirror test is like teaching someone the answers to an IQ test. You haven't made them smarter, you've just increased their score on the test. APL (talk) 22:21, 11 June 2010 (UTC)

Actually... In my anthropology class, we learned that there was evidence that a dog could be aware of the fact that not only is it thinking, but the dogs/people around him are too. I don't know how to explain that concept better, but that awareness of self and others is a theory as to why humans are compelled to communicate thoughts whereas chimpanzees are not. Interestingly, wolves are not believed to be aware in the same way that a dog is. I am thinking this is relevant to the discussion, because to identify sentience of oneself would (I would think) have to be a prerequisite for identifying the sentience of others. 65.87.167.166 (talk) 00:19, 12 June 2010 (UTC)

, What evidence? I'd be interested in knowing, I thought that the mirror test was the only widely accepted test for this sort of thing, even with its flaws. The Wikipedia article supports that view, but perhaps it's missing whatever research you're talking about? APL (talk) 04:26, 12 June 2010 (UTC)

To be clear, the Mirror test does not test sentience. It tests "Self awareness" which is a component of sentience. APL (talk) 18:29, 11 June 2010 (UTC)

It's a pretty terrible test - if it works and the animal passes the test - then it shows...something. But if an animal "fails" the test, it could just be that the animal doesn't care - or that the animal has other senses that are not fooled by the mirror. Think of this from the point of view of (say) a dog: The blurry monochrome image doesn't smell like a dog...the end. From the point of view of a shark: The blurry image doesn't emit electrical pulses from muscular activity that can be picked up from your lateral line...so it's not relevent. Those animals could easily be self-aware, but simply not care about your wildly unrealistic tests. On the other hand, I could easily write a computer program for a robot that could detect it's own reflection - measure changes between images taken on consecutive visits past the mirror and react to differences accordingly. The robot would clearly not be "self-aware" in any interesting fashion...so even a positive reaction to a test doesn't actually 'prove' anything. Since neither a positive nor a negative result actually proves anything much - the test should be treated with appropriate amounts of skepticism. SteveBaker (talk) 15:38, 12 June 2010 (UTC)

Well, computers could pass just about any cognitive test if the specific criteria of the test are designed into the software, that doesn't prove anything. If I knew the questions on an IQ test, I could program a computer to fill in the scantron ovals flawlessly. That proves nothing about either computers or IQ tests.

And, obviously, the test will give false negatives, even after you augment the mirror with olfactory cues. It's the positives that are interesting. (Although some animals clearly fail. Parakeets, for example.) APL (talk) 01:08, 14 June 2010 (UTC)

P.S. Don't dogs have bichromic vision?

Assuming the validity of the strong AI assumption, the answer is in principle contained in the algorithm that describes the animal. Count Iblis (talk) 16:12, 12 June 2010 (UTC)

I think all animals are sentient. Just that we, in our limited intelligence dont realise it. —Preceding unsigned comment added by 78.100.32.20 (talk) 10:50, 13 June 2010 (UTC)

Spoof SETI

How hard would it be to spoof SETI? I mean something like putting a satellite in geostationary orbit (or approximately anyways since the SETI equipment is not at the equator) and sending extremely low power transmissions back to them? Googlemeister (talk) 13:25, 11 June 2010 (UTC)http://en.wikipedia.org/w/index.php?title=Special:UserLogout&returnto=Wikipedia:Reference_desk/Archives/Science/2010_June_11&returntoquery=action%3Dedit%26section%3DT-9

It would be trivial to determine the origin of any transmission from an object orbiting Earth. It would be only slightly less trivial to determine the origin of any signal from within tens of light years. So no, nobody is going to spoof SETI. — Lomn 13:30, 11 June 2010 (UTC)

I should explain a little bit. Any local signals can have their origin determined by parallax. In the case of Earth-orbit signals (and probably for anything within the main solar system), two receivers on opposite sides of the Earth create sufficient parallax to determine where a signal comes from. That would take a matter of hours, at most, to determine. For large distances (up to 1500 light years, give or take) you need up to six months, allowing the diameter of Earth's orbit to serve as the baseline. The only way you could "spoof" SETI would be to recreate the Wow! signal, which didn't last long enough to allow for more than one observation -- but since there wasn't more than one observation, SETI doesn't treat that as anything approaching a positive hit. So no spoof. — Lomn 14:08, 11 June 2010 (UTC)

Also, to be clear, large radio telescopes and arrays of telescopes have a small beam—they only "see" a small part of the sky at once, just like a large optical telescope only sees a small part of the sky at once. They're not going to detect any random signal sent to them, like a transistor radio would. They have to be pointed at the transmitter. -- Coneslayer (talk) 14:21, 11 June 2010 (UTC)

As an aside, anyone who has the enormous money and means to try place a satellite and attempt to fool SETI has a whole lot of more interesting things to do with their time and treasure. Richard Avery (talk) 16:05, 11 June 2010 (UTC)

That's not as true as it once was. Some tiny satellites are theoretically within the range of a middle-class individual. They wouldn't go into geostationary orbit, though, they'd be in much less desirable low-orbit locations. (You couldn't really run a con with a geostationary satellite anyway. They're too high-profile.)

If you can fit your SETI hoax into a satellite the size of a coke can, here's a launch option that might even fit on your credit card : [7] APL (talk) 22:34, 11 June 2010 (UTC)

Yes - but let's be really clear: SETI have comprehensive procedures that allow them to easily eliminate signals coming from airplanes and spacecraft within roughly the orbital distance of the moon. Beyond that - if a believable signal came from further away, they'd need to observe it for a while to be utterly sure that it was not something within the solar system, etc. Their processes are really meticulous - you couldn't 'spoof' them - it's just not remotely reasonable. (On the other hand, those coke-can sized satellite thingies are awfully interesting.) SteveBaker (talk) 15:24, 12 June 2010 (UTC)

You could fool them for a while if you know those comprehensive procedures well enough, though. Pick a SETI listening station and find out what station they use to corroborate signals and check the parallax. Then you use two unidirectional transmitters sending the same signal, with the appropriate phase difference, from two different blimps (or similar). The difference in the locations of the blimps would (if you calculated it right) look like the parallax from a signal several light years away. It wouldn't fool them for long (they would just need to check with a third listening station, which they would do very quickly), but you would cause a bit of excitement for a few minutes. --Tango (talk) 02:25, 13 June 2010 (UTC)

For the sake of answering this question, let's lump all of SETI into one category: "radio signal analysis." (Needless to say, there are other branches of SETI, but this is the most relevant to the question). Now, as you probably know, one of the most fundamental, oldest, and simplest techniques for analyzing radio signals is to detect the range and location of the source. Give the SETI guys some credit - if they detect a signal, don't you think they will attempt to determine where it came from? There are a lot of spoofs you could play - you could, for example, throw some electronic countermeasures technology on your satellite, (like a stealth aircraft), and try to fake your position - but it's much harder than you might think. Once the signal is analyzed from two or more stations, it will become obvious that your spoof signal is being injected from here on Earth. Nimur (talk) 01:37, 12 June 2010 (UTC)

I think the main problem is that no object in the solar system can stand still because of gravity (except maybe a solar sail), so seen from the earth it would have the wrong apparent angular velocity. This is especially true for earth orbiting satellites (for example an geostationary satellite will appear to stand still in the sky, any real signal is expected to rise once each 24 h just like the stars.). It will is a litebit harder if the source is in solar orbit, for a real world example see http://www.youtube.com/watch?v=WPprykBiIgg at 4:00 to 5:40, they are confused by signals from the SOHO solar orbiting space probe for 16 h.(He calls it a satellite but it is not.)

I think it would be very hard to spoof signals from outside the solar system by a transmitter in the solar system without manipulating the equipment used by several independent research groups. Of curseee it is easier to spoof extraterrestrialialial probe (http://en.wikipedia.org/wiki/SETI#Probe_SETI_and_SETA_experiments) but probably the spacecraft will be traced from launch so it will not be able toNASAl Nasa and others.Gr8xoz (talk) 20:21, 14 June 2010 (UTC)

Etching on the cheap

I'm an artist and I want to experiment with etching, so today I've been rounding up some equipment. I bought some ferric chloride from an electronics shop (they use it for etching circuit boards). Finding a cheap source of suitably-sized pieces of sheet metal was difficult: my current best option is some baking trays. These are "traditional tin plate", so I presume they're the same as tin cans, i.e. made using a tinning process. My plan is to paint the tray with "ground", engrave the image, pour in the ferric chloride, and when it is beautifully etched, print off a few copies by means of ink and paper and rubbing with the back of a spoon. What I want to know is:

1. Am I making a stupid chemical mistake which will create a cloud of poison gas?
2. What's a cheap supermarket-bought substance that might work as a "liquid hard ground"?

213.122.46.177 (talk) 15:53, 11 June 2010 (UTC)

1. No poison gas - (I'm not sure if ferric chloride will etch tin - but probably will). I'm nearly 100% certain than baking trays are not tin plated though.. You can get brass or copper sheet online (prices seem to be ~5£ (8$) for a small sheet). There's probably a cheaper way of getting etchable metal sheets - maybe "copper clad board" for pcb making would be suitable - they're cheap.

2. As a guess - nail varnish , don't forget the nail varnish remover - again online you can buy the remover very cheap as acetone. Possibly other forms of varnish ( eg wood varnish/lacquer) may be suitable.87.102.13.41 (talk) 17:21, 11 June 2010 (UTC)

You'll probably like this http://www.ganoksin.com/ftp/edinburg-etch.pdf not only does it describe ferric chloride etching - but has instructions on making grounds too. Acrylic paint might also be good - you can dissolve this using methanol, or acetone, or MEK amongst other methods.87.102.13.41 (talk) 18:01, 11 June 2010 (UTC)

Windmill on a car ?

How feasible is the idea of fixing a windmill like arrangement on a car, to generate some electricity, so as to say charge up the battery a little or power up the AC ? Is the idea worth giving an experimental trial ? Rkr1991 ^{(Wanna chat?)} 16:32, 11 June 2010 (UTC)

The laws of thermodynamics say it's not practical, assuming you mean you want to use the "wind" of the air staying in place as the car moves forward to spin the windmill. The extra energy needed to overcome the drag produced by the windmill and move the extra weight would be greater than the power produce because of inefficiencies. If you mean parking your car in a windy area and doing something for a while, then coming back and folding your windmill into your trunk or something before you leave, that's a different story. 76.229.205.199 (talk) 16:37, 11 June 2010 (UTC)

(ec)It depends. Putting a small windmill up there to take advantage of the wind when the car is not moving might be useful, to keep a battery topped up or even that car cold or warm without burning fuel. But if you want to utilize the air flow generated by the cars own movement, then no, its a waste of energy. Its less efficient than directly using the car's alternator. --Stephan Schulz (talk) 16:39, 11 June 2010 (UTC)

Your windmill idea is used already by airplanes, though — see Ram air turbine — but this is to generate power if all the engines fail, not to try and boost efficiency. Comet Tuttle (talk) 16:42, 11 June 2010 (UTC)

A turbocharger essentially uses the "wind" generated by expelled exhaust gases to improve the efficiency of the car engine by generating additional compression. The turbine in a turbocharger is not functionally different than a windmill. It just sits in the exhaust path inside the car rather than in the air outside of the car. --Jayron32 19:29, 11 June 2010 (UTC)

These are often used on yachts. It may harvest energy from the wind, as I expect cars spend most of 24 hours stationary, even though it would increase the drag of the car and hence increase the amount of fuel used. 92.15.25.9 (talk) 21:18, 11 June 2010 (UTC)

I actually saw on the freeway south of San Francisco a car with what seemed to be a wind turbine attached to the roof. Later I saw several of them in a parking lot at Google's Mountain View campus. I didn't investigate further, but now I wish I had because my web searches aren't turning anything up. My immediate reaction when I saw it was "that's ridiculous", but after thinking about it some more I'm not so sure. A turbine can obviously give you a net gain when the car is parked and there's a breeze, and it's not clear to me why that would cease being true if the car was moving. The air-ground speed differential exists independently of the car's motion. -- BenRG (talk) 22:40, 11 June 2010 (UTC)

Here's a proof of concept: a purely wind-powered vehicle that can travel downwind faster than the wind. -- BenRG (talk) 23:17, 11 June 2010 (UTC)

Going faster than the wind is used on sailboats, by the way, basically by keeping constant wind at an angle to the direction of motion so that some wind is always hitting your sail on the side. SamuelRiv (talk) 07:58, 12 June 2010 (UTC)

Thanks for a fascinating link. It proves that energy can still be obtained from the wind when moving downwind faster than the windspeed, but I would question whether the small amount of energy that can be obtained in this way will significantly affect fuel consumption. I would guess that most of the extra energy would be lost in an inefficient transmission and in extra drag from the supporting structure. Has anyone done any trials? Dbfirs 08:29, 12 June 2010 (UTC)

There actually is at least one example of a vehicular power system that used the energy of the vehicle's motion to produce electricity (for lighting etc.) as a normal mode of operation. The generator was driven by the wheels, not a windmill. I'm talking about passenger train cars. Today the electricity they need is generated on the locomotive ("head end power") and a set of wires runs through the train. But the steam locomotives that trains used to use didn't have generators on them, so the cars were provided with the wheel-powered generators instead. (There were batteries that provided power when the train was stopped and recharged from the generator when it was moving again). Similarly, train heating was provided by steam from the locomotive -- if these cars were used with a diesel locomotive, the train had to carry a boiler to generate steam for heating. --Anonymous, 10:40 UTC, June 12, 2010.

• Correct me if I'm wrong, but I think some of the above answers seem to be a little confused..... There is most certainly going to be a drag as the car moves forward, and with respect to the car, a breeze flowing in the opposite direction. My idea is just to use that breeze to power a battery, energy which would have been wasted otherwise. I don't see why any laws of Thermodynamics would prevent me from getting useful energy out of this, despite the inefficiencies, and I also don;t see how the situation changes when the car is still or in motion..... With respect to the car, it's just the same, right ? As an extrapolation, how would the idea work, if applied to say trains, with rows of windmills on behind another on top of the train, all generating a little electricity ? Rkr1991 ^{(Wanna chat?)} 12:06, 12 June 2010 (UTC)

The breeze you feel when you move through still air, and the force that breeze might exert on a windmill, are examples of drag. It's just another way that your car would be less aerodynamically shaped. The more sources of drag there are, the harder the engine has to work or the slower the car would move than it would otherwise...i.e., your car becomes less energy-efficient at driving. So you use more fuel to drive the same speed--there's your added energy cost. The gain is that you can get some energy out of the windmill. But you will get less energy from the windmill than you put in as extra fuel (the engine->rolling-friction->air-turbulence->windmill->generator-friction all involve losses of efficiency). DMacks (talk) 14:53, 12 June 2010 (UTC)

Rkr1991, haphazardly adding windmills to a moving vehicle is unlikely to help matters, because it will add a lot of drag. But DMacks, I don't think there's a straightforward thermodynamic argument that windmills must be a net loss, and I don't even think it's true. For one thing, if the air is moving relative to the ground then energy can be extracted from that differential by a vehicle moving at any speed in principle. And even if the air is stationary relative to the ground, I see no reason why adding windmills coupled to the drive train in some way couldn't reduce your net loss to friction. Drag doesn't add linearly. I can't even see how to prove that adding a windmill in a carefully chosen location couldn't reduce the overall drag, even if you don't recover any power from the windmill—it seems very unlikely, but not obviously impossible. In fact, wouldn't a proof along those lines be worth a million dollars? -- BenRG (talk) 21:30, 12 June 2010 (UTC)

Per "with respect to the car, a breeze flowing in the opposite direction", I assumed the air current we're talking about--the air motion that would drive the windmill on the car, relative to its frame of reference--was due to that car motion. If there's additional air motion (actual weather/wind) relative to the ground, then you could recover that just as for a stationary windmill mounted on the side of the road. DMacks (talk) 22:11, 12 June 2010 (UTC)

Let's say I am able to somehow position the windmill such that it doesn't add tp the drag. First of all, is this possible? Second, If I do, will I now be able to get useful energy out of it ? Rkr1991 ^{(Wanna chat?)} 03:03, 13 June 2010 (UTC)

No, it's not possible! That's exactly the point. In effect this is converting the vehicle's kinetic energy into electricity, and that means it is consuming that energy, and that means it causes drag. --Anonymous, 05:10 UTC, June 13, 2010.

Have a fold-down windmill, to reduce drag when the car is moving (except with a tail-wind). Oh, and you've forgotten to mention adding a kite or sails to the car to pull/push it along. 92.28.252.46 (talk) 13:36, 13 June 2010 (UTC)

No. If you managed to position the windmill so that it didn't add drag (say, in the trunk) then it would not turn. The drag is how it works. The propeller spins by slowing down the air around it. (Or, from another perspective, slowing down a car going through still air.) APL (talk) 01:00, 14 June 2010 (UTC)

That is not true, of cursee the windmill will have drag but the combined drag of the car and the windmill are not necessary greater than the car alone, the turbulence from the windmill could delay the separation of airflow on the car, see for example http://www.youtube.com/watch?v=nufXpDBELdQ from 1:50. Of curse for this to work the windmill will need to be very small and will not produce any significant power.

Gr8xoz (talk) 20:55, 14 June 2010 (UTC)

On a still day, If the windmill turns the energy to turn it is coming out of the car's forward velocity. APL (talk) 14:16, 15 June 2010 (UTC)

With a tail-wind, the wind would have to be going faster than the car to get any energy out of it. A 50mph wind is - I guess - a storm wind or worse. With a front-wind, you could get some net energy if the wind was fast enough to overcome the loss in energy to drag. 92.15.28.6 (talk) 17:35, 15 June 2010 (UTC)

Protein breakdown for energy... trigger?

What's the trigger for your body starting to break down protein for energy? I know this happens with long-distance runners who have no other alternative energy source. I'm looking for an exact mechanism; I assume it's triggered by a lack of glucose being detected, but what happens on the molecular level for this process to begin? Regards, --—Cyclonenim | Chat  17:07, 11 June 2010 (UTC)

This is not an area of expertise for me, but the "Regulation" section of the gluconeogenesis article gives some information. It says that the main activators are acetyl CoA, which is produced by metabolism of fatty acids, and citrate, which is produced in the basic Krebs cycle. Of course the availability of the substrate (unused amino acids) is also important. In fact any protein you eat that your body can't use will be converted to energy, because there is no other way for the body to get rid of it that isn't harmful. Looie496 (talk) 18:33, 11 June 2010 (UTC)

Looking at this again, I realize that I didn't actually address the question -- but the answer seems to be that the causes of protein catabolism aren't all that clearly understood. The breakdown of protein in lean muscle cells apparently results mainly from the ubiquitin pathway, but that's an extremely complex process that is affected by many factors. It seems, though, that low levels of insulin in the bloodstream are one factor that upregulates it. Looie496 (talk) 21:20, 11 June 2010 (UTC)

Right Handed Dominance

So, why is it that a majority of the population is right-handed? Why are there such things as right and left hand dominance and what purpose does this serve? Is this an evolutionary trait or what? Thanks! Stripey the crab (talk) 18:57, 11 June 2010 (UTC)

There is no proof that we know the answer, but the general story is probably that there are certain brain functions (most notably language) that don't work well when both sides of the brain participate in them, probably because of the time delays involved in sending signals from one hemisphere to the other. Thus, a number of functions get segregated mainly to just one hemisphere, some to the right, others to the left. This segregation would have to be controlled by genes, and it would be hard to design a genetic scheme that would, for example, place the language system on one side but be neutral about which side it is. It happens that fine motor control of the hand is segregated to the left hemisphere in most people (which controls the right hand). I realize that this explanation is a bit hand-wavy, but I don't think it is possible to be more specific based on what we currently know. Looie496 (talk) 19:23, 11 June 2010 (UTC)

(edit conflict) There is some discussion of the issue in the article Handedness, but the actual reasons why right handedness dominates are likely arbitrary. There's probably a good reason why one hand dominates, and it arbitrarily became the right hand. It likely could have easily been the left hand (cats, IIRC, are left-paw dominant usually), but it ended up being the right. There are some sketchy connections to "divisions of labor" in the brain (i.e. the "right handed people are analytical, left handed people are artsy), but these sorts of connections are VERY tenuous and have little scientific support behind them, they are mostly bullshit. The real reason is likely just random chance chose the right to be the dominant one in most humans, and it stuck. --Jayron32 19:24, 11 June 2010 (UTC)

it is because the physical environment is predictable and not at all postmodern, artistic, and emotional. if people were raised in a pure emotional environment in which repeating the same action did not result in the same effect from the physical environment, but rather depended on its "mood", you would find children would end up left-handed. This is my original research, so as with my other reply, if the nobel committee needs to contact me you will have to reply here as I am not allowed to include my email address. 85.181.50.245 (talk) 20:32, 11 June 2010 (UTC)

A related question involves amino acids. Philosophy of chemistry#Foundations of chemistry (permanent link here) says "Left-handed amino acids and right-handed sugars are the basis of the chemistry of life." -- Wavelength (talk) 21:47, 11 June 2010 (UTC)

Note for the gullible: 85's answer above is purest bullshit and should not be treated as even vaguely science. 86.164.69.239 (talk) 22:01, 11 June 2010 (UTC)

I've heard that the reason for right-handedness being more common in humans is that women will tend to carry their babies with there non-dominant hand, and carrying the baby on the left will make it closer to the heart, which makes the environment feel more like the womb. This makes the baby happier, less likely to cry, and I assume less likely to attract predators. Of course, this raises the question for why nearly all humans have their hearts on the left. (See Dextrocardia). — DanielLC 06:12, 14 June 2010 (UTC)

Have humans been historically right handed? I mean, if you look at ancient Egyptian and Babylonian paintings, do the warriors seem to show hand preference? Googlemeister (talk) 15:41, 14 June 2010 (UTC)

energy harvesting is so stupid

OR without a question, with a solicitation to the Noble/Nobel Prize Committee.
The following discussion has been closed. Please do not modify it.
i think the current ways of harvesting energy are really stupid, they should just build a couple of wormholes, one to the surface of the sun, and one to someplace cold, and use the heat differential to get energy. the wormholes don't have to be very big since you are not really transferring much through it. the text above told me not to include my email address so please reply here if you need to contact me. (nobel committee). 85.181.50.245 (talk) 20:26, 11 June 2010 (UTC) Reply to what? ---Sluzzelin talk 20:32, 11 June 2010 (UTC) to what I've written here. They might need it more fleshed-out before they go handing out the prize, which of course I understand. 85.181.50.245 (talk) 20:33, 11 June 2010 (UTC) Yeah, but were not secretarys for the noble prize comittee - you need this webpage http://nobelprize.org/ I know geniuses have difficulty dealing with everyday things but this is ridiculous.77.86.125.56 (talk) 20:44, 11 June 2010 (UTC) Were not secretaries for the noble prize committee what? What were they? 92.15.25.9 (talk) 21:23, 11 June 2010 (UTC) There's a missing apostrophe - it should read "we're not" - most people would have been able to work that out.. you're obviously not of the same mental calibre as the original poster.77.86.125.56 (talk) 21:31, 11 June 2010 (UTC) No one knows how to build a wormhole, and there are good reasons to think that wormholes may not actually exist. If you can demonstrate a way to create wormholes, you might well get a Nobel prize, but speculating about how hypothetical wormholes might be used isn't going to get you anything. Dragons flight (talk) 20:43, 11 June 2010 (UTC) I recommend building a working prototype, and selling the electricity back to the power company. Your profits could easily exceed the Nobel prize money, and any additional surplus could be used to buy one of those nifty Nobel medallions used. APL (talk) 22:40, 11 June 2010 (UTC)

Ant stamina

I've had the opportunity over the last few days to watch ants crawling over my kitchen counter. I notice they don't stop to rest for any reason. In fact, they never stop moving. Do they get tired the way we mammals do? Or, do they go back to the nest to sleep? Hemoroid Agastordoff (talk) 21:10, 11 June 2010 (UTC)

There seems to be very little science relating to ant sleep, but this paper (published last year) reports that fire ants do sleep, but only inside their nests, and only in short bouts. Looie496 (talk) 21:27, 11 June 2010 (UTC)

June 12

Atomic mass unit

Why are the values for 1 amu different if you use 1/12 the mass of a carbon-12 atom instead of 1/16 the mass of an oxygen-16 atom? The former has 12 nuclear particles of equal mass, and the latter has 16 nuclear particles of equal mass to each other and to the particles in a carbon-12 atom. --75.25.103.109 (talk) 00:41, 12 June 2010 (UTC)

See Binding energy#Mass deficit. The different nuclei have different binding energies, so different mass deficits. It's also worth nothing that protons and neutrons don't actually have the same mass (although it is very close). That doesn't affect your example, since they each have half protons and half neutrons, so the average mass is the same, but if you are talking about heavier nuclei (which need disproportionately more neutrons to be stable) it becomes an important factor. --Tango (talk) 00:48, 12 June 2010 (UTC)

Tornado recurrence rate

I remember reading this in a book at some point, but I have never been able to find it since. What is the recurrence rate of a tornado striking any given point in the tornado-active areas of the United States Great Plains, say in Kansas or Oklahoma? The statistic I remember reading was something on the order of once every *insert number above 500 here* years, but I have never been able to find the statistic again. The context I remember it being used in was to explain how very rare and against all odds such events as Codell, Kansas's (struck by tornadoes on May 20th of three consecutive years) or Mulhall, Oklahoma's (struck by two violent tornadoes within a 2 hour time frame) tornado events are. Ks0stm ^(T•C•G) 02:47, 12 June 2010 (UTC)

This site says "Even in tornado alley, a twister hits a given square mile only once every 700 years" but it's not well referenced. Regards, --—Cyclonenim | Chat  11:19, 12 June 2010 (UTC)

Female Survival

Ok, I know this will sound incredibly stupid, but I'm going to ask it anyway. If a woman was stranded somewhere without food or water, could she drink milk from her own breasts to survive? Or would the lack of nutrients cause the milk to lack any nutritional benefits? Could the energy and nutrients be recycled through the body< of would it be lost? If so, how quickly? Again, I know this sounds incredibly stupid, but I realize that I have been wondering about this for quite a while now. Thanks for the help, and please don't think I'm some kind of weirdo for asking this! Stripey the crab (talk) 03:10, 12 June 2010 (UTC)

Of course not! It takes energy to produce milk - and by the basic laws of thermodynamics, it must cost more energy to make than can possibly be gained by consuming it! SteveBaker (talk) 03:40, 12 June 2010 (UTC)

However, she might be advised to read up on urophagia before getting stranded.--Shantavira|^{feed me} 06:23, 12 June 2010 (UTC)

Conservation of energy 82.43.89.11 (talk) 11:24, 12 June 2010 (UTC)

Yes, she could, but the longer she lived on the less nutrional it would be until she died of starvation. You could survive a while on your own scabs, excrement, urine etc. Only a bit longer than going without food but it would prolong life nonetheless.--178.167.206.65 (talk) 13:41, 12 June 2010 (UTC)

But would there be any advantage to drinking your own milk? If you stop breast feeding, you'll soon stop lactating and I would imagine any milk left would be reabsorbed. --Tango (talk) 17:06, 12 June 2010 (UTC)

A transverse wave

Visit [8] and go to question 12. These are my answers for part a:
Frequency: 10 Hz, 10 Hz
Amplitude: 0.2m, 0.15m (or perhaps 0.14m)
Wavelength: 2m, 1m
Speed of wave: 20m/s, 10m/s

But now I'm stuck on question b. How do you do it?--220.253.96.217 (talk) 04:10, 12 June 2010 (UTC)

From your answers to part (a), you can determine that the transmitted pulse (travelling to the right on the heavy string) will have a smaller amplitude than the original pulse. I would think that the reflected pulse (travelling to the left on the light string) would have an even smaller amplitude (most of the energy will go into the transmitted pulse) but it will be travelling twice as fast as the transmitted pulse. If you take a snapshot at, say, 0.1 s after the original pulse arrives at the junction, then the transmitted pulse will have travelled 1m to the right, and the reflected pulse will have travelled 2m to the left. You are only expected to sketch the appearance of the two pulses, and part (b) is only worth 3 marks as opposed to 6 marks for the quantative answers in part (a), so you don't need to very precise. Gandalf61 (talk) 09:35, 12 June 2010 (UTC)

The answer can be found here [9] by the way, but what I want is not the answer itself, but how you work the answer out.--220.253.96.217 (talk) 11:12, 12 June 2010 (UTC)

Computer components from petrochemicals

Which computer components (if any) are made from which materials derived from petroleum? -- Wavelength (talk) 07:17, 12 June 2010 (UTC)

The Integrated circuit encapsulation, any Insulator (electrical), epoxy in the Printed circuit board, engineering plastics in the DVD drive, external parts eg keyboard keys.77.86.125.56 (talk) 08:10, 12 June 2010 (UTC)

And lest we forget all the electricity needed to build the components, and where that comes from. Regards, --—Cyclonenim | Chat  11:17, 12 June 2010 (UTC)

It is unlikely that the electricity to manufacture electronic components comes from petroleum (or even natural gas). See the charts in electricity generation. For the United States, half the energy for electricity comes from coal, natural gas is nearly a quarter, almost all of what is left is nuclear; and the remainder is a tiny sliver of renewables, bio-fuels, hydro-energy, and geothermal. A tiny (minuscule) fraction of electricity comes from petroleum. An even smaller fraction comes from solar production. Furthermore, most electronics components are manufactured overseas (specifically, China, where coal is overwhelmingly the largest source of the energy for electricity). Very little petroleum is used to provide energy during the manufacture of those electronic components. Nonetheless, petroleum is used in massive scales to transport the materials - and transportation is the single largest energy-consuming sector (if you can call it a single sector). Nimur (talk) 16:35, 12 June 2010 (UTC)

Thank you all for your answers. Although I was hoping for more detailed information, I appreciate the information provided.
-- Wavelength (talk) 15:06, 13 June 2010 (UTC)

How about the following: FR-4, Integrated circuit packaging, Integrated circuit encapsulation, Potting (electronics), Resin dispensing? In the old days, circuits were packed in ceramic; nowadays, plastics, epoxies, silicone derivatives, and resins are more common; silicone is made from Dimethyldichlorosilane, made from Chloromethane, made from methanol, which is made in industrial scales from natural gas (methane). Epoxies are often made from epichlorohydrin, which can be made from heavy asphaltenes, paraffins, and petroleum residues. Similarly, if you click through the "production" or "synthesis" sections of most of the other constituents, and trace back far enough, you'll find the eventual source chemicals. Most of the electronics are not at all derived from petroleum or petrochemicals - but the packaging (without which the electronics would be useless) are petrochemical-derivatives. Furthermore, photoresist (a critical step in modern VLSI electronics) is also a petrochemical derivative. Hopefully this is a little more specific for at least some sub-areas of the electronic components - your original question covers so broad a topic that it is difficult to be both complete and specific. Nimur (talk) 16:21, 13 June 2010 (UTC)

heat

my power went out today when it came back on my gas central heat only pumps out cold air not hot air. i dont have any AC. how do i fix this ? its like my thermostat isint communicating with my heater properly. —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 08:12, 12 June 2010 (UTC)

It could be several problems. It could be a defective safety on your furnace to prevent keeping the flame on when no blower is on. It could be your thermostat, but that is more unlikely with battery powered thermostats. --Chemicalinterest (talk) 10:59, 12 June 2010 (UTC)

could the power going out ruined or damaged the thermostat? —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 11:34, 12 June 2010 (UTC)

and whats weird it has a space for a battery but i havent used one in years. when the power came back on the thermostat wouldent even turn on and i had to put in batteries to even make the display show up. why is that? it ran for years fine on house power. in the past when the power went out it came back on no problem. —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 11:42, 12 June 2010 (UTC)

If your system is anything like my gas-fired hot water central heating system, Alexsmith44, then if your heater is not heating the air the burners may not be lighting, which suggests that the pilot light that ignites them may be out; this pilot light usually maintains a high temperature in a thermocouple which, if not hot, prevents gas from flowing to the pilot light and the main burners in order to prevent a large escape of gas blowing up your house. (Lighting the pilot usually requires you to manually over-ride the pilot light cutoff until the thermocouple is up to temperature.) Lighting the pilot usually requires either piezolectric spark ignition (usually achieved mechanically by pushing a button) or a spark derived from a battery or the mains electrical supply.

Is your pilot light lit? If not, the power cut may have caused it to go off for safety reasons, and you need to relight it, which will require the relevant components to be in good shape and the exact procedure in your appliance manual to be followed. If you are in any doubt about any of this (for example, if you don't have the manual) then call a qualified gas appliance engineer - gas appliances are too dangerous to be tinkered with by someone who doesn't know what they're doing.

If none of this is relevant, and/or you do know what you're doing (though if so why are you asking here?) then you have my apologies, but please don't risk blowing up yourself and your building! 87.81.230.195 (talk) 18:09, 12 June 2010 (UTC)

can anyone explain why when the power came back on the thermostat wouldent even turn on and i had to put in batteries to even make the display show up.

There are almost certainly too many different configurations of this general sort of system for anyone to have a chance of diagnosing such problems unless you say exactly what make and model your system is (and even then there would be no guarantee that anyone answering here could do so).

One thing I should add to my previous post: if your system includes a pilot-light-heated thermocouple, it might have failed when or after the system went down, or when you tried to restart it. Such thermocouples are probably the most failure-prone component of gas-fired heating systems - my own boiler's thermocouple failed at least 3 times during a 20-year period.

Even if anyone answering here can correctly guess the cause of your problem, you're not going to be able to be sure they're right, you're probably not going to be able to fix it, and you're going to run the risk of causing more damage to the system or yourself if you try but get it wrong, so you're going to have to call in a qualified engineer who will be able to make a sure diagnosis and carry out a safe repair/replacement. He/she is the person to ask. 87.81.230.195 (talk) 04:24, 13 June 2010 (UTC)

Some thermostats run on electricity created from the heat of the pilot (and so don't need a mains or even a battery connection). But it won't work without a heat source. Rmhermen (talk) 00:27, 14 June 2010 (UTC)

I hope the OP didn't live here! 87.81.230.195 (talk) 03:28, 14 June 2010 (UTC)

BP gulf oil issue: Geology question

Forgive my ignorance on the matter, but I was just curious about something: the world is focusing on the oceans and shores and flora/fauna, etc etc (and rightly so). But emptying at an estimated rate of 40,000 gallons a day, what's happening to the pocket where the oil is originally coming from? At what point would the pressure/weight of the ocean collapse the oil pocket? What would be the extent of the damage this incurred, or would the "earth" not even notice (like earthquake or tsunami, etc)? – Kerαunoςcopia^◁_galaxies 10:08, 12 June 2010 (UTC)

In most cases extracting oil or gas from a reservoir has relatively minor effects, as the hydrocarbon in the rock pores is replaced by water. The thing to remember is that we're not talking about a hole in the ground filled with oil, but a rock with maybe 20% porosity. Mikenorton (talk) 10:22, 12 June 2010 (UTC)

Just to expand a little on my response above, as the oil comes out, the pressure in the reservoir will reduce, something known as depletion, and this will lead to some compaction of the reservoir unit from the pressure of the overlying rock. In some cases this has led to induced seismicity on a small-scale [10] and minor seafloor subsidence [11]. Mikenorton (talk) 13:30, 12 June 2010 (UTC)

Cats and mirrors

A follow-up to the discussion above at Wikipedia:Reference_desk/Science#Sentience.2Fconsciousness, my cat will watch me reflected in dark glass (doors, windows, all at night, reflecting the lighted interior well), and if I walk up to him quietly and kneel down, he'll watch me, then turn around and come to me. He's also waited at the door to be let out, but instead of meowing at me me, he'll watch me in the reflection, and when I arrive, look up at me again. He's obviously aware that he's the "little guy" in the reflection and I'm the taller one lol. Um, I guess my silly question would be, what does this prove? – Kerαunoςcopia^◁_galaxies 10:15, 12 June 2010 (UTC)

it proves you have an enviable amount of free time! 92.230.234.180 (talk) 10:37, 12 June 2010 (UTC)

It means animals can understand mirrors. --Chemicalinterest (talk) 10:57, 12 June 2010 (UTC)

No, it means cats (not all animals) are aware of their own reflection and potentially other things in the reflection. Cats are creatures of habit, if they see a reflection every time before the door opens, they'll associate that reflection with an opening door. They're also acutely aware of their surroundings, just because he/she looks up at you as you arrive doesn't mean they necessarily saw you in the mirror. Regards, --—Cyclonenim | Chat  11:14, 12 June 2010 (UTC)

I don't see why any part of the OP's story means that cats are aware of their own reflection. The story was entirely about identifying a reflected human shape as a human (and the assumption about awareness of "the little guy" came out of the blue). The cat doesn't react to its own reflection as it might do to a real cat on the other side of the glass, but that doesn't indicate awareness, only some basic filtering out from the cat's attention of objects that move in sync with the cat's muscle movements. (There might be a name for this, I forget - proprioception?) 213.122.19.215 (talk) 11:26, 12 June 2010 (UTC)

How does anyone know that cats are not aware of their own reflection?--178.167.206.65 (talk) 13:44, 12 June 2010 (UTC)

See Mirror test. Deor (talk) 13:51, 12 June 2010 (UTC)

The problem with the mirror test is that it is incapable of distinguishing between self-awareness (in this sense, the ability to recognize that the object in the mirror is a reflection of the self) and self-consciousness (an ability to compare the reflection against an internal self-representation to note differences). Animals who fail the mirror test (such as cats and dogs) may in fact be aware that the mirror is reflecting them, but may not recognize that the test dye that the researcher placed on them is something unusual or abnormal. clearly some animals do fail the test completely (e.g. budgerigars and beta fish, who respond to reflections with affection/aggression, the way they would when confronted with a separate creature), and clearly some few non-human animals which are capable of self-consciousness, but there's a decent-sized grey area in between. --Ludwigs2 14:29, 12 June 2010 (UTC)

Wouldn't that be easy to check by first placing the paint somewhere that the cat doesn't need a mirror to inspect? I have a difficult time imagining a cat, looking down at its own paw and not being irritated by something that a researcher did to its fur. APL (talk) 15:28, 12 June 2010 (UTC)

you'd have to be careful not to be confused by cats' normal irritation at being messed with. for instance, if you were to put a cat under anesthesia first (so it wasn't aware of the process) and dye its paw blue, I am not at all sure how much the cat would be disturbed by its newly blue paw, assuming the dye was tasteless, odorless, not irritating, etc... Clearly primates would be disturbed by such things (as demonstrated by numerous pranks played on drunk dorm-mates), but cats and dogs? remember, cats and dogs are often taken if for grooming, which can involve extensive changes in bodily appearance as fur is shaved away, but they are not generally perturbed by it. --Ludwigs2 16:35, 12 June 2010 (UTC)

Clearly it implies that the cat does not fully understand mirrors, if it's treating the reflection and the person as separate entities. But I'm not sure that it even implies that very strongly. Even if it does understand mirrors it might be treating it as a separate entity for amusement. Cat's like toys. So I'm not sure that it proves or even strongly implies anything.

Anyway, The point of the mirror test is not to check if the animal understands mirrors in general, but to check if they can recognize their own image. APL (talk) 15:28, 12 June 2010 (UTC)

It surprises me how much importance people place on mirror recognition. For a cat to recognize its reflection in a mirror is not in principle different from recognizing its own paw when it looks at it -- the fact that the light bounces off a reflective surface before reaching the eye has no philosophical significance. All animals that are capable of damaging their own bodies need robust self-recognition mechanisms to prevent that from happening, and mirror recognition is just that same process in action, as far as I can see. It raises a number of interesting practical issues, certainly, but I don't understand why it would raise philosophical issues. Looie496 (talk) 17:21, 12 June 2010 (UTC)

This brings to mind the all the times I've seen cats fail to recognize their own paws, and accidentally start washing the furniture. 213.122.16.179 (talk) 19:23, 12 June 2010 (UTC)

Breathable boots

I was watching How It Works earlier and it showed a factory making breathable, waterproof boots using Gore-Tex. The commentator said that it keeps water out whilst allowing steam/sweat to leave because these molecules "are 20 times smaller than water molecules". I call bullshit on that, water molecules and steam molecules are going to be the same size because steam IS water, with more kinetic energy and less dense. This also raises the question of why steam would need to escape. As far as I'm aware, human feet don't get hot enough to generate steam! So how does this system really work? Regards, --—Cyclonenim | Chat  11:12, 12 June 2010 (UTC)

(commentator's explanation was wrong)

Goretex (which see) allows water vapour out via the tiny holes, but doesn't allow water droplets in. As you know water droplets tend to stick together, and thus do not tend to break up - so they don't/can't break into tiny water droplets to go through the tiny holes.77.86.125.56 (talk) 11:18, 12 June 2010 (UTC)

Also, water vapour forms below 100C - eg evaporation - when you sweat the water evaporates, but your skin is not at boiling point, the difference is that air below 100C can only have a certain smaller amount of water vapour in it.77.86.125.56 (talk) 11:21, 12 June 2010 (UTC)

Boiling point is the point where the pressure of the water vapour (see vapour pressure) is the same as the ambient pressure, which allows bubbles to form and rise to the surface, allowing very rapid evaporation. The amount of water vapour that can remain in the air is related (that amount is the vapour pressure), but it isn't the key difference, since it is a gradual change. --Tango (talk) 02:15, 13 June 2010 (UTC)

I would expect that condensation on the cool inner surface of the boots from the warm vapour from your warm body is going to ruin the breathability anyway. 92.15.30.42 (talk) 11:52, 12 June 2010 (UTC)

Grass in flower beds

I've always had a problem with lots of grass growing in my flower beds. I have two situations: a) ground dug up in the early spring, annual flower seeds sown. b) perennial or biannual plants sown last year, so the ground could not be dug over - the bed looks like uncut grass with leaves in it. Is there any solution to getting rid of the grass except pulling out every grass blade one by one, a Herculean task? Thanks 92.15.30.42 (talk) 11:44, 12 June 2010 (UTC)

Not really enough detail on what the plants are to answer this, and you might be better off in some of the excellent gardening forums around on the web. Depending on the perennial plants but in general grass is not very good at pushing through wood shreddings compared to many (but not all) perennials. Strimming down the grass as much as possible and then spreading a 2in layer of bark or wood chip over everything might work. --BozMo talk 12:46, 12 June 2010 (UTC)

That would probably kill all the plants as well though. 92.15.0.254 (talk) 18:08, 12 June 2010 (UTC)

This depends on whether the grass is perennial creeping or whether it is annually seeded. If it is annually seeded then you need to get on the job at regular intervals in the spring and summer and pull it out before it seeds. If the grass is a creeping perennial type then you have a much harder problem to solve. No amount of pulling out will kill the grass in the long term because you will almost certainly leave bits of root behind which will regrow, and they will come through wood chips without a problem! For perennial grass you will either have to dig up the whole plot at some point that will not disrupt the flower display or by very carefully using a small brush to apply herbicide to the grass - of course I understand this might be totally impractical. First determine by the careful removal of a dozen or so sample grass plants if they are annual (self-contained clumps with fine roots) or perennial (attached to underground spreading roots). It may be a mixture of both types. I hope for your sake it is the former. You are not alone [12] Caesar's Daddy (talk) 14:57, 12 June 2010 (UTC)

For particularly tough grass such as (couch grass), I find that the best solution is glyphosate weedkiller applied with a paint brush so as to avoid affecting the nearby plants. This requires lots of patience, but it is very effective. Dbfirs 15:47, 12 June 2010 (UTC)

Do you think it would work if I applied the weedkiller during the winter? Thanks 92.15.0.254 (talk) 18:12, 12 June 2010 (UTC)

The plant has to actually be growing, and not dormant to be killed in this way with glyphosate, but if your winter is warm enough for continual growth it should still kill it. Graeme Bartlett (talk) 21:56, 12 June 2010 (UTC)

gear box vs belt pulley

For an 18 KW motor (~25hp), I use a 'v' belt (c type) to convert the speed from 900 to 450 rpm. An alternative is to replace this with a gear box. I believe the advantage of the gear is higher efficiency although with maintenance issues. Now without having actual data about the difference in efficiencies of the 2 and the annual/monthly maintenance cost involved with the gear box, is there any reason to prefer one over the other? The load connected to the motor is prone to slight vibrations every now and then. Thanks —Preceding unsigned comment added by 122.169.217.4 (talk) 13:06, 12 June 2010 (UTC)

Wear on the belt system is primarily on the belt - maintenence is replace the belt, compare this with maintenence on the gears (which may not even be possible - once the teeth are worn that's often it.) - the device will be out of action for much longer.

87.102.84.163 (talk) 15:13, 12 June 2010 (UTC)

What about a chain drive?87.102.84.163 (talk) 15:19, 12 June 2010 (UTC)

Actually summarised here [13] one big factor is if slip is acceptable, and the size of those torque variations.87.102.84.163 (talk) 15:22, 12 June 2010 (UTC)

Vellus hair

In Vellus hair it is said that exceptions (for vellus hair) include the lips, the backs of the ears, etc. The back of the ears usually has a very soft down generally and a few thick strands of hair occasionally. Isn't this an error then/?--117.204.94.179 (talk) 13:28, 12 June 2010 (UTC)

Pure OR of course, but the backs of my ears lack any hair apart from a few thick strands on the edge of the helix. Mikenorton (talk) 14:54, 12 June 2010 (UTC)

The backs of my ears are hairless but those of my cat are furry. I changed the title for easier reference. Cuddlyable3 (talk) 16:45, 12 June 2010 (UTC)

Are you sure? Those hairs are usually not dark and very short and almost invisible. You can try to pick them closely between two fingertips. Maybe, they are visible when you stand against bright sunlight as coming through the door way of a bright morning.--117.204.82.21 (talk) 01:41, 13 June 2010 (UTC)

You could have some moles on the backs of the ears that produce dark hair, I suppose. --Tango (talk) 02:10, 13 June 2010 (UTC)

No, not growing on moles. I am talking of a soft, fair down. Unfortunately I don't have a girl friend now to check it with somebody else. --117.204.88.50 (talk) 05:14, 13 June 2010 (UTC)

How to get a sponsorship

Hello,

My research paper has got selected in an international conference by IEEE http://www.icmee.org/ . I was a student of my college a month ago when i submitted that paper.Currently i have passed out.So,i could not find that how could i arrange the huge sponsorship amount.scientists at that end,Kindly help.I have just graduated in b.tech mechanical Engineering. Pardon me for asking an off topic question. Sameerdubey.sbp (talk) —Preceding undated comment added 15:23, 12 June 2010 (UTC).

Welcome to the harsh world of science. You have to find funds to do research, it seems to me the most appropriate way in your case would be to apply for a Ph.D research position... 15:51, 12 June 2010 (UTC)

You could do well to write to people who work in your field of interest. Let them know that you know about their work (from publications?) and tell of your own. Suggest that you would like to meet at the conference. Listen to and value their advice. Cuddlyable3 (talk) 16:29, 12 June 2010 (UTC)

Your question is not entirely clear. Are you asking how you might obtain funding to cover the costs of attending the conference, or funding to cover the costs of continuing your research? If you need funds to attend the conference, I would be surprised if the college you were a member of cannot give you either a small grant for this purpose, or at least advice on where to apply elsewhere for one, since your achievement must reflect well on them. If you need funds to continue your career, again your former college ought to be able to give you advice, but attending the conference, talking to more senior scientists there about your paper, and asking them for advice or directly for employment would be one strategy. 87.81.230.195 (talk) 17:45, 12 June 2010 (UTC)

The OP is probably in India, where money does not grow on trees, and the conference is in Japan, which is expensive to visit. But the reality is that if the supervisor of the project can't fund the travel, it is unlikely that anybody else will. Some academic conferences pay for travel for a certain number of students, but IEEE is more business-oriented and probably doesn't. I should also point out that IEEE conferences generally accept everything that is submitted to them, so having a submission accepted isn't a mark of prestige. Looie496 (talk) 17:53, 12 June 2010 (UTC)

Sameer, I notice that quite a number of people on the Program Committee are from India. If one of them happens to be from your own college, or from nearby, you could contact him to ask for suggestions. Looie496 (talk) 18:06, 12 June 2010 (UTC)

One thing to bear in mind is the OP didn't actually say where their university/college was located. The OP is probably from India, but whether their university/college is there wasn't stated. I initially thought the OP has been studying at the US because they said 'college' but on second thought if they were doing a B.tech in ME they may have done it at something called a college in India. Nil Einne (talk) 22:40, 12 June 2010 (UTC)

Using sea water in toilets

What are the difficulties in using sea water (directly, without desalination etc) in Flush toilets ? Barring the additional cost of plumbing and also the problem of corrosion of the taps etc (which I suppose can be solved by using plastic or other corrosion resistant materials), what prevents us from implementing this ? It would save a lot of water (approx 20 liters per flush) - WikiCheng | Talk 17:01, 12 June 2010 (UTC)

A third problem is that waste water is treated with bacteria before the water is drained to seas/rivers/whatever, and currently known efficient bacteria won't live in salty water. If you manage to bioengineer salt resistant bacteria (if you are into biotech, there's a nice project for you, go for it!), I guess you are pretty much left with the financial equation: desalinate vs. invest in duplicate pipe systems. Or triplicate: where I live we have two drain systems, one for rainwater and one for sewage; salt water sewage might require a third one, unless you want to mix your kitchen sink sweet water sewage with the salty toilet sewage. 88.112.56.9 (talk) 17:20, 12 June 2010 (UTC)

The article Head (watercraft) notes the use of sea water to flush toilets on boats. In submarines the high external water pressure makes this difficult. Cuddlyable3 (talk) 17:49, 12 June 2010 (UTC)

One could also ask why we don't use grey water in toilets. I can't say for certain, but I imagine that it's primarily the difficulty of running/maintaining the extra set of piping and storage, rather than any properties of the water itself. Fresh water is still cheap enough in most places (especially with low flow toilets) not to be worth the hassle. Also, getting the sea water to Nebraska (or even 100 km inland) would be a hassle. -- 174.24.195.56 (talk) 18:02, 12 June 2010 (UTC)

Using industrial quality water is toilets is pretty common wherever it's cheap enough to have two sets of pipes (or simply not to pipe drinking water). Physchim62 (talk) 20:21, 12 June 2010 (UTC)

They have been doing exactly that in Hong Kong for quite a while now (see Water supply in Hong Kong). But unless it's a densely populated coastal city the cost of laying and maintaining 2 sets of pipes might more than offset the cost and fresh water savings. --antilived^{T | C | G} 01:39, 13 June 2010 (UTC)

Unless you also have separate sewers, using seawater would actually be harmful. If your home is connected to a sewer system, you can't really "waste" water. Any water you use is recycled by the next city downriver from you. (Each city picks up water from the river, uses it, treats, and puts in back in the river for the next city downstream to use.) So it should be obvious that putting salty water in a freshwater river is something you should avoid, both for the river itself, and also for the next city downstream. Home Kong probably has no one downstream - they probably dump their sewage into the ocean. Ariel. (talk) 09:56, 13 June 2010 (UTC)

They use sea water on oil platforms to flush the toilets. There is at least recorded accident because the same sea water system was used for heat exchangers for cooling live crude as well. The sea water had jammed up every directional valve and corroded through the heat exchanger resulting in a flammable gas mixture being evolved into the toilet through the cisterne. Someone was smoking on the toilet (am pretty sure the whole platform was a non smoking zone although the toilet was in the crew "safe haven") and got a nasty surprise. Which highlights I guess that handling seawater through conventional plumbing is not straightforward. --BozMo talk 13:55, 13 June 2010 (UTC)

Thanks for your answers ! I forgot to mention the phrase 'at least in the cities near the sea' in my question :-). But I am surprised that it seems to be an issue of cost and preventing accidents (as stated by BozMo) rather than any technical problem - WikiCheng | Talk 04:04, 14 June 2010 (UTC)

Watering plants

Is it beneficial to urinate over garden plants? Or would the salt in the urine be harmful to them? A Wikipedia article says that drinking urine in survival conditions should never be done due to its salt content, so would urine be harmful to plants too? 92.15.0.254 (talk) 18:20, 12 June 2010 (UTC)

They'd get burnt from the acid too. YOu should see what female dog urine does to lawns! --TammyMoet (talk) 19:38, 12 June 2010 (UTC)

Yes, mostly the acid. Try urinating over a test plant, if you wish. You will quite quickly (one or two weeks of regular urinating, I'd say) that the plant turns brown and dry, just as if it were dead from lack of water. However, I know from observation of urinated-over lawns that some plants, especially some species of moss, survive the urine and thrive, whereas grass is burned. Of course the moss then makes it harder for the grass to grow back. In short, unless you want a moss garden, don't. --Alþykkr (talk) 22:33, 12 June 2010 (UTC)

I would guess that the moss is still being harmed by the urine, just not as much as the grass, so benefits from the lack of grass. The benefit from there being less grass around could very easily be greater than the harm from the urine. --Tango (talk) 02:09, 13 June 2010 (UTC)

(Edit Conflict) Actually wetting plants with urine would, as already stated, probably 'burn' them, but (human) urine is a useful source of nitrogenous fertilizer for the soil; discussions of this I have heard/read in the past usually recommend storing it for a time in a (sealed) container rather than adding it 'fresh' (just keep a plastic screw-top bottle next to the toilet, and add to it as and when). Googling on "Urine gardening" returns many hits discussing the topic in detail. 87.81.230.195 (talk) 22:37, 12 June 2010 (UTC)

This is a common question on "Gardener's World" type programs. The consensus seems to be you should wee on your compost heap but not directly on to plants. All the panelists last time I heard this on the radio admitted they did this (even the ladies) although there were technique variations. --BozMo talk 14:05, 13 June 2010 (UTC)

On the other hand if they are weeds and your urine does kill them would seem an effective and fairly safe weed killer Nil Einne (talk) 06:03, 14 June 2010 (UTC)

brushed nickel

what is brushed nickel ? and can it cause dermatitis —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 20:05, 12 June 2010 (UTC)

See Nickel#Toxicity. hydnjo (talk) 20:25, 12 June 2010 (UTC)

yes but is brushed nickel the same as reg. nickel does it have a coating —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 20:29, 12 June 2010 (UTC)

According to the WP article "Brushed metal" it is perhaps hot rolled, annealed, pickled and passivated. Of course it can be coated (as anything else) but I don't think that's what you were asking. hydnjo (talk) 20:57, 12 June 2010 (UTC)

Rechargeable Battery: voltage rebound

When a device powered by rechargeable batteries depletes the battery, it stops working because the voltage is not high enough to power it. But I've noticed that if you leave the power off for a while, the voltage of the battery rises without charging. And if you wait long enough (10 min - 1 h) and then turn the device on, the it will work again, although probably with a low battery warning. I have seen this happen in cell phones, cameras, gameboys, and any device using rechargeable AA/AAA batteries.

What causes this voltage rebound? I'm taking about the NiMH and Li ion types mainly. --Yanwen (talk) 21:29, 12 June 2010 (UTC)

This is common across all cell types and is caused by Polarisation: "An effect produced upon the plates of a voltaic battery, or the electrodes in an electrolytic cell, by the deposition upon them of the gases liberated by the action of the current. It is chiefly due to the hydrogen, and results in an increase of the resistance, and the setting up of an opposing electro-motive force, both of which tend materially to weaken the current of the battery, or that passing through the cell." The effect vanishes when the battery is allowed to rest with no current. I'm looking for a Wikipedia article on this. Do we have one? Dbfirs 21:38, 12 June 2010 (UTC)

Depolarizer ? Battery chemistry is quite a big topic - I'm suprised there isn't more here.

Thanks, 87, I'd missed that. The effect still seems to be called polaris(z)ation, even though the chemistry varies. Dbfirs 07:57, 13 June 2010 (UTC)

... also from the history of cells at "Battery and Energy Technologies" [14] "Volta's simple voltaic cell cannot operate very long because bubbles of hydrogen gas collect at the copper electrode acting as an insulator, reducing or stopping further electron flow. This blockage is called polarisation. Daniell's cell overcomes this problem by using electrolytes which are compatible with the electrodes. Thus the zinc electrode is suspended in an electrolytic solution of zinc sulphate which is contained in the porous pot (Initial designs used sulphuric acid rather than zinc sulphate). The porous pot is in turn immersed in the copper sulphate solution which is contained in a glass jar into which the copper electrode is also suspended. The Daniell cell does not produce gaseous products as a result of galvanic action and copper rather than hydrogen is deposited on the cathode. Daniell's non-polarising battery was thus able to deliver sustained, constant currents, a major improvement on the Voltaic pile." The chemistry will be different in NiMH and Li ion types, but the principle is the same. The effect becomes more noticeable as the battery becomes weaker. Wikipedia does have a short paragraph at Primary_cell#Polarization. You might also be interested in this patent application. Dbfirs 21:52, 12 June 2010 (UTC)

The situation in Lithium batteries is different due to lack of production of Hydrogen - a similar effect may be produced in Li cells by locally (near the electrode) increased concentrations of Li+ ions reducing the cell EMF - these will take time to diffuse away. Note:this is one possibility - I haven't got a full analysis of the processes in Li cells.

I think this accumulation of reacted lithium is still a form of (ie is called) polarisation. 87.102.84.163 (talk) 01:03, 13 June 2010 (UTC)

Yes, the 2009 patent (above) uses the term "polarization" for the effect in Lithium cells. The original problem was with hydrogen, but the term just means accumulation of ions or molecules near to one (or both) of the poles. Dbfirs 08:06, 13 June 2010 (UTC)

Cauterization as an emergency measure

Why is it that cauterization is never mentioned as a possible (although obviously... not optimal) way to stop heavy bleeding in an emergency ? Is it only because of practical purposes (the emergency rescuer is unlikely to have a source of heat with him or near him), or because of inefficiency/dangers ? I know cauterization is extremely painful and causes tissue damage, but in the event bleeding can't be stopped even with a tourniquet (or if the tourniquet can no longer be maintained because of risk of limb loss), would cauterization be an interesting last-resort solution ? Thanks in advance, --Alþykkr (talk) 22:28, 12 June 2010 (UTC)

Probably because it is very rarely useful. Even tourniquets often aren't taught on first aid courses these days. Direct pressure, elevation and pressure points can do the job in pretty much all circumstances where tourniquets or cauterization would help. If cauterizing wounds was useful, it wouldn't be hard to include a suitable tool (either gas powered or electric) in the bags paramedics carry, or even in first aid kits. --Tango (talk) 22:58, 12 June 2010 (UTC)

According to the 'SAS survival manual' (probably not really - but that's what it was called, though I believe it was written by an ex-SAS guy) I had as a teen, cauterization is only to be used as a last resort in a situation where no rescue is imminent, say if your plane just crashed in the Andes (or something) and someone's legs are hanging off. There was a caveat that cauterization will actually cause some people to drop dead from shock. --Kurt Shaped Box (talk) 23:07, 12 June 2010 (UTC)

An observation by a nonmedical person: Cauterizing , say an artery after some traumatic amputation smacks of 18th century naval battles. But electrocautery does seem to be used today to stop small bleeders in operations. Edison (talk) 01:31, 13 June 2010 (UTC)

Indeed, it is used for small blood vessels that you can get to precisely. They only touch the cauterizing thing to the blood vessel itself. It is very different to cauterizing a wound from the outside with a big red-hot poker. That means there is no real tissue damage, other than to the blood vessel that has been damaged by severing it anyway. --Tango (talk) 02:06, 13 June 2010 (UTC)

June 13

Flaming blood

First, is there any way that a substance could be produced which would cause a person’s blood to burst into flames? Second, if such a substance could exist, could it be contained in a pill form?--99.251.239.89 (talk) 02:52, 13 June 2010 (UTC)

There are substances that burst into flame on contact with water (which blood mostly is), but nothing that could actually cause the blood itself to burn. If you used something that burst into flame on contact with water, it would have to be injected - if swallowed, it would burst into flame somewhere in the digestive system. --Tango (talk) 02:56, 13 June 2010 (UTC)

Potentially you could have a pyrophoric (air reactive) material which would cause the blood to erupt in flames when it hits the oxygen in air (but not while it's still in the body). Most pyrophoric substances are water reactive too, though, and even those that aren't may react with the dissolved oxygen in the blood, or will be toxic even without bursting into flames. -- 174.24.195.56 (talk) 04:23, 13 June 2010 (UTC)

I think if you got such a substance to a high enough concentration for it to work, it would be toxic. --Tango (talk) 15:32, 13 June 2010 (UTC)

Wouldn't humankind be capable of surviving an overacting solar flare after all?

At the end of this film, (apparently) everybody on Earth dies when a solar flare gets overactive enough to strike our planet. However, what if some people are in submarines? How deep underwater can this kind of solar flare cook anything? How thick would the submarine's walls need to be in order for everyone inside to withstand the onslaught, should a solar flare even be able to cook that far underwater in the first place?

Also, I think solar flares would only cook the daylight side of the planet. How long would this kind of solar flare stick around? Would it stick around long enough to cook the night side once it's morning for them?

Moreover, what of people who are currently underground - in subways, etc.? What of the people who got enough warning to get to a bomb/fallout shelter deep underground? How far underground would they have to be in order to stay safe?

If a handful of humankind could survive the Sumatra volcano 70,000 years ago, I'm sure we can survive rogue solar flares now. --Let Us Update Wikipedia: Dusty Articles 03:28, 13 June 2010 (UTC)

The human race has been around for about 2 million years in its current form, during that time there have been plenty of large solar flares, yet we are still here. The Earth's magnetic field and atmosphere protect us. The film is complete fiction with no basis in reality (were the telepathic aliens that can predict the future not a give-away?). --Tango (talk) 03:48, 13 June 2010 (UTC)

Thanks, T. So if a solar flare as large as in the movie happened real soon, can you confirm whether we'd be able to protect ourselves by either diving deep underwater or running deep underground as described above? Or how else would we manage to survive this kind of solar flare, if you know of other ideas? --Let Us Update Wikipedia: Dusty Articles 04:53, 13 June 2010 (UTC)

I suppose if the giant solar flare happened to coincide with the expected reversal of the Earth's magnetic field (sometime during the next few thousand years), then most of the mammals on Earth might be affected. There might be some extinctions, but it would be unlikely to include humans - there are just too many of us in too many different environments. Science has little experience on which to base predictions, so we can only guess. The flare at a time of very low magnetic field would have a drastic effect on civilization though. Dbfirs 07:37, 13 June 2010 (UTC)

You need a nearby GRB to do significant damage, see e.g. here. Count Iblis (talk) 18:05, 13 June 2010 (UTC)

The most likely scenario for significant disruption of our high-tech civilization is for a solar flare to overload and destroy large numbers of power transformers at northerly and southerly locations. Because the manufacturing capacity for power transformers is limited, it would take a long time to replace the transformers. Jc3s5h (talk) 18:17, 13 June 2010 (UTC)

virus more active during rainy season?

I read in a newspaper editorial that virus infecting human beings become more powerful during the rainy season. Is there in truth in it?--117.204.90.213 (talk) 05:16, 13 June 2010 (UTC)

Viruses tend to spread more rapidly when humans are in closer contact (e.g. in winter in some countries), but I don't know of any evidence that rain affects the virus itself. Can anyone find any research? Dbfirs 07:40, 13 June 2010 (UTC)

Not true, viruses are not lifeforms, they are just rather complex protein machinery. In winter, they are not changed structurally to appear any different to any other time of year, so there is no reason to believe a virus would become stronger in winter. However, weakened immune systems are at more risk of contracting diseases in cold, winter seasons. That's why a lot more people catch influenza over winter than at any other time of year, but it has nothing to do with the virus itself. Regards, --—Cyclonenim | Chat  10:24, 13 June 2010 (UTC)

When it comes to influenza, Influenza#Seasonal variations & Flu season deals with this somewhat. As with many things, the truth is we don't really understand that well why flus are seasonal. The greater close contact almost definitely plays a part (as Dbfirs has noted) but so could other things like the virus surviving on surfaces for longer (which may be partially due to changes in the viral structure from the different temperatures), dehydrated mucus and possibly a weakened immune system that Cyclonenim notes above. Lower vitamin D levels have also be proposed as a possible cause. One interesting thing is that while it's suggested a lower humidity may contribute, in tropical (& I think most subtropical ones) regions I suspect like wherever the OP is in India (Kerala?), the flu season tends to be the rainy months where some of the earlier mentioned factors would hold true or somewhat true but lower humidity generally wouldn't (although the humidity may always be fairly high so this could perhaps be why it's not a big factor). Our articles also discuss other potential factors like interaction with other diseases and school terms. As I've noted it's almost definitely a combination of factors but how much of contribution each one makes we obviously don't really know and potentially/probably? different ones in different regions. Nil Einne (talk) 13:07, 13 June 2010 (UTC)

Viruses and other infectious agents generally survive better in water than in dry air, and during the rainy season in hot climates there tend to be a lot of droplets of water floating around, as well as water on the ground that can be splashed. It makes a huge difference: during the colonial era in tropical Africa, it was considered nearly suicidal to travel during the rainy season -- almost all the exploration was done during the dry season. Looie496 (talk) 16:59, 13 June 2010 (UTC)

Are you sure the exploration wasn't more to do with mosquitos? Nil Einne (talk) 01:04, 14 June 2010 (UTC)

Maximum/Minimum Irradiance..?

Maximum/Minimum Irradiance (solar constant) range for a "Human habitable" planet/planet-moon
to have a habitable Global Annual Average Surface Temperature?
I am referring to a habitable planet for people, and not extremophiles.
I am referring to Global Annual Average Surface Temperature, as in 14°C for Earth,
and therefore don't mean Mercury's cold side, or Venus's upper atmosphere, or Pluto's core;
Pluto, Venus, Mercury, like planets could be habitable but are not in the Goldilocks Zone,
and I am only asking about heating by the parent star, which is the main factors,
any other factors spinning things better can't be counted on like influence of the parent star itself.
We may find "liquid water" near the core of Pluto, but the chances of people living there are nearly nil.
The solar contant for the Earth is 1366.08 Watts per Meter squared,
but that is for the semi-major axis (100%), but this value varies from 103.43% to 96.74%,
and Venus' varies from 193.93%-191.30%-188.73%, and Mercury's from 1058.11%-667.69%-459.36%.
I am confident in what I am asking and don't need question improvement suggestions,
or other angles, tangents and sidetracks; If you think there is something wrong with the question,
then you just don't understand it, and please don't bother.

Take for example a large moon of COROT-9b: (exoplanet.eu)
Star Radius = 0.94 sol
Star Te = 5625 K
Stefan–Boltzmann constant, σ = 5.67051E-8
Semi-major axis = d, in this case 0.407 (± 0.005) AU
Eccentricity = e, in this case 0.11 (± 0.04)
=(((0.94*6.955e8)^2*(5.67051e-8)*(5625^4)) / (0.4069*149597870690)^2) /1366.0875

PIO	Ecc. min. 0.07	Ecc. avg. 0.11	Ecc. max. 0.15
Periastron:	553.96%	604.88%	663.15%
Semi-major axis :	479.12%	479.12%	479.12%
Apastron:	418.48%	388.87%	362.29%

• Note that if the maximum is lowered then the minimum is raised.

I used this example because Europe's CoRoT space telescope team has obviously lied
to the journal Nature (3/10), reporting "CoRot-9b is circling its star in a "temperate" orbit.

Irrandiance Habitable Candidates?

This is not part of my question, just here for examples.

Planet	Radius (Sol)	Photosphere Temperature (K)	Semimajor axis (AU)	Orbital eccentricity	Perihelion Irradiance	Average Irradiance	Aphelion Irradiance	Period (Yrs.)
Mars	1.0	5778	1.523	0.0934	52.45%	43.11%	36.06%	1.8795
HD 141937 b	1.06	5821	1.52	0.41	151.57%	52.76%	26.54%	1.79
HD 187085 b		6011	2.05	0.47	191.84%	53.89%	24.94%	2.7
HD 23079 b	1.13	5848	1.65	0.1	68.65%	55.61%	45.96%	2.02
ups And d	1.631	6212	2.55	0.32	124.54%	57.59%	33.05%	3.56
HD 99109 b		5272	1.105	0.09	71.72%	59.39%	49.99%	1.20
HD 10697 b	1.72	5641	2.16	0.1	77.76%	61.60%	49.99%	2.947
HD 147513 b	1	5701	1.26	0.52	279.84%	64.47%	27.91%	1.48
HD 213240 b	1.5	5984	2.03	0.45	219.53%	66.41%	31.58%	2.6
HD 45364 c		5434	0.8972	0.0974	82.15%	66.93%	55.57%	0.939
HD 196885 b	1.79	6340	2.37	0.462	231.99%	67.15%	31.42%	3.65
HD 210277 b	1.1	5532	1.1	0.472	258.97%	72.20%	33.32%	1.21
HD 136418 b	3.4	5071	1.32	0.255	188.72%	74.90%	39.91%	1.27
HD 183263 b	1.21	5888	1.52	0.38	196.35%	75.48%	39.63%	1.73
HD 160691 b	1.245	5700	1.5	0.128	103.07%	78.37%	61.59%	1.76
HD 125612 b	1.05	5897	1.2	0.39	213.56%	79.47%	41.13%	1.37
HD 28185 b	1.03	5482	1.03	0.07	93.69%	81.03%	70.77%	1.05
HD 190228 b	3.02	5176	2.31	0.43	262.13%	85.17%	41.65%	3.09
Gliese 876 c	0.36	3350	0.132	0.266	162.61%	86.65%	53.73%	0.083
HD 188015 b	1.1	5520	1.19	0.15	120.50%	87.06%	65.83%	1.25
HD 16175 b	1.87	6000	2.1	0.59	548.49%	92.20%	36.47%	2.71
HD 100777 b		5582	1.03	0.36	237.79%	97.40%	52.66%	1.05
Earth	1.0	5778	1.0	0.01671022	103.43%	100.00%	96.74%	1.0
HD 108874 b	1.22	5407	1.051	0.07	119.47%	103.33%	90.25%	1.08
HD 155358 c		5760	1.224	0.176	155.02%	105.26%	76.11%	1.45
HD 142415 b	1.03	5834	1.05	0.5	425.29%	106.32%	47.25%	1.06
HD 20367 b	1.18	5929	1.25	0.23	185.73%	110.12%	72.79%	1.37
HD 82943 b	1.12	5874	1.19	0.219	182.79%	111.50%	75.03%	1.21
HD 221287 b		6304	1.25	0.08	136.29%	115.36%	98.90%	1.25
HD 45364 b		5434	0.6813	0.1684	167.83%	116.07%	85.02%	0.62
HD 92788 b	0.99	5559	0.97	0.334	221.33%	117.95%	73.13%	0.89
HD 153950 b	1.34	6076	1.28	0.34	329.92%	143.71%	80.04%	1.37
HD 69830 d	0.895	5385	0.63	0.07	166.74%	144.22%	125.96%	0.54
Venus	1.0	5778	0.723	0.0068	193.93%	191.30%	188.73%	0.6148

Given the best possible conditions, (that is I not asking for an atmosphere that is so large that it would be warm past the orbit of Mars, but the pressure would crush a person, and that kind of nonsense.) what would be a stable range for irradiance for a "habitable for people" Global Annual Average Surface Temperature on an Earth-like planet or planet-moon; The range must be larger than Earth's 103.43% to 96.74%, less than Mercury's 1058.11%, and more than Mar's 36.06%, but what are the maximum and minimums??
24.78.167.139 (talk) 05:26, 13 June 2010 (UTC)

You have obviously done a lot of research on this yourself, so you might be the best person to answer your own question. I must admit that I don't understand it because, as mentioned last time, so many other factors are relevant. Dbfirs 07:43, 13 June 2010 (UTC)

The papers cited in our Habitable_zone article might provide interesting reading, if you haven't already, to see what assumptions and models the authors used. As Dbfir says, you might be the most in-the-know person here about what you're after. Brammers (talk/c) 08:33, 13 June 2010 (UTC)

This is actually the first step to what I considered a more complex question, but it may be the other way around to answer this part, if I just plug in Albedo and Emissivity of the Earth, I could use a similar formula to calculate the Global Annual Average Surface temperatures of those same planets in the chart (or planet-moons there) but to make use of that angle of solving the problem I would then need to know what are realistic/stable Global Average Albedo's and realistic/stable Global Average Emissivity, Almost a catch 22. So, because of those suggestions I hunted down this MADSCI Question/Answer from long ago, because you may be right, I may have to go study cosmochemistry and geology to answer this question without anyone's help. 24.78.167.139 (talk) 09:53, 13 June 2010 (UTC)

I don't know why you are asking questions at the same time as saying "because Europe's CoRoT space telescope team has obviously lied to the journal Nature". Firstly accusations of lying in a scientific paper are very grave, perhaps you mean you believe they are mistaken in their results? Perhaps they mean something other than what you mean? Secondly you really need to show they are wrong before saying they are so why the questions about working it all out? Have you gone through their workings carefully? Dmcq (talk) 16:37, 13 June 2010 (UTC)

The OP has asked variations on this question many times in the past. He or she seems unwilling to accept that there are huge uncertainties in the field of planetary science and extrasolar planet characterization. It is not possible to put a boundary on irradiance for the habitable zone unless you explicitly state your assumptions. Define habitable zone. Define a suitable temperature range. State your assumptions about the planetary parameters (albedo, atmospheric greenhouse effects, thermal re-emission, orbit parameters, and so on). Once you have defined those notions, it will be trivial to give you a "percentage" for the stellar irradiance to yield a particular temperature range. The biggest problem with your formulation is that you have jumped over these extremely critical problem definition stages and have started demanding numerical values. This is equivalent to demanding "how much fuel would an airplane take?" How can we answer such a question with a numerical value? You haven't asked for anything. We cannot give you a numerical value unless you specify your problem better. Nimur (talk) 17:44, 13 June 2010 (UTC)

Furthermore - regarding whether Deeg, Moutou, et al. "lied" in their paper: have you read the paper? Here it is: A transiting giant planet with a temperature between 250 K and 430 K. I wonder how you can be more specific than that: they tell you right in the title - the error bars are so uncertain that the planet temperature might be too cold for liquid water, the right temperature for liquid water, or too hot for liquid water. The error bars are so huge, that any possible scenario is plausible, based on available measurements and data analysis. Regarding whether they characterize this as "temperate":

“ Its periastron distance of 0.36 astronomical units is by far the largest of all transiting planets, yielding a ‘temperate’ photospheric temperature estimated to be between

250 and 430 K.

” — H.J. Deeg, Nature 464, 384-387 (18 March 2010)

They even put "temperate" in quotation marks - to indicate that this is a hand-wavey term! But they actually told you the temperature ranges that they have deduced. In science, we prefer quantitative analysis over vague terminology any day. Nimur (talk) 22:10, 13 June 2010 (UTC)

I would also point out that many journals will allow intelligent and reasoned feedback on articles within a few months after they are published. (For Nature [15] would probably be the correct way.) You can also contact the authors. However given the comments and questions you (24.78.167.139) left on the RD there's a good chance any feedback you have will be ignored. (Nature for example says "All contributions should be measured in tone, and should not contain inflammatory or otherwise intemperate language".) In particular, accusing the authors of lying is likely to get you automatically ignored which isn't surprising considering it's potentially defamatory (and this paper appears to include about 30 authors to boot). In other words beware the pitfalls befalling this infamous Conservapedia#Lenski dialogue [16]. But if you genuinely believe in your claims, consider writing a more reasoned and betterr worded response and submitting it rather then making claims to random people with no connection to the paper. In other words, put your money where your mouth is. If you have genuinely discovered a major error in the paper, I'm sure they'll be happy to know. Nil Einne (talk) 01:39, 14 June 2010 (UTC)

is risk from smoking linear with amount smoked?

if person A smokes 1/5th as many cigarettes as person B, then is person A 1/5th as likely to get any health complications? (I read from the health effects of tobacco that it is "stochastic" (like a lottery) for many cancers, etc: either you get it or you don't.) 85.181.49.30 (talk) 09:27, 13 June 2010 (UTC)

I could be wrong, but I wouldn't imagine this is the case. For a cancer to occur, a complicated series of events needs to occur, a lot of things need to fail and you need to be quite unlucky. This is because you need genetic damage to be caused to cancer preventing genes and repair genes, AND THEN you need to have another situation where the gene which switches on and off cell division gets stuck on the 'on' switch. At this point, cell division becomes uncontrollable and you have yourself a tumor. But of course, there are any number of factors which can cause genetic damage and it's impossible to predict accurately for every day life. You can['t] predict which X-ray, gamma ray, carcinogen etc. which will directly cause the damage, so I'd believe it is indeed stochastic. Regards, --—Cyclonenim | Chat  10:29, 13 June 2010 (UTC)

Much like there is a concept of ED50 and LD50, when assertions are made about the association of tobacco consumption and cancer, it is merely a statistical significance that happens to be clinically significant as well. All posted data are averages. That being said, how do you get 1/5 of a lung cancer? It would also depend upon a potential carcinogenic plateau effect, and so percentages cannot be the only things stated (i.e. you'd have to provide absolute parameters as well). Currently, though, smoking can be classified by "pack years", and so person A who smokes 1PPD x 4 years and person B who smokes 2PPD for 2 years are both said to have smoked for 4 pack years. Do they necessarily match each other in terms of severity of risk? You certainly bring up a good point. DRosenbach ^{(Talk | Contribs)} 13:55, 13 June 2010 (UTC)

And again, it's worth emphasizing and reemphasizing the probabilistic nature of this. What these "risk" factors means is that out of a population of X number of people, Y number would be expected to have health complications. It doesn't really mean, "this individual has this particular chance of getting cancer"—cancer is not a rolling of dice. It also does not take into account the complexities of individual exposure—it cannot rule out all of the other variables involved. (For example, if you smoke and are exposed to high radon levels in your home, your chances of getting cancer are very high indeed, much higher than if you "just" smoke or if you "just" have high radon.) --Mr.98 (talk) 14:23, 13 June 2010 (UTC)

Let me guess - you're a smoker. 92.15.14.150 (talk) 20:04, 13 June 2010 (UTC)

Why would you assume that? I'm not a smoker, and I find it very irritating when people talk about smoking as leading inexorably to specific consequences for every person. Not only is it bad science and bad statistics, it's self-evidentally not true. If you misrepresent the risks of smoking as one set of consequences that happen to everyone, people only have to know one smoker who didn't experience those consequences to reject everything ever said about the dangers of smoking, since it was clearly not true. And most people know a smoker who didn't get lung cancer, for example. Far better to be honest about it. 86.164.69.239 (talk) 20:59, 13 June 2010 (UTC)

I'm not a smoker, and am quite against smoking. But that has nothing to do with whether I think people misunderstand the nature of probabilistic risk. I think that smoking is clearly a health problem without resorting to misunderstanding, and that such a misunderstanding leads to even more ridiculous pro-smoking positions like those outlined by 86.164. Truly "getting" what risk factor data actually means lets one actually make sensible choices and understand why anomalous results obviously exist (like the oft-cited grandparent who smoked every day and lived to age 95). --Mr.98 (talk) 21:57, 13 June 2010 (UTC)

Whilst I agree with 86 and Mr. 98, it's important not to overexagerate the risk of smoking, it's important to reinforce the idea that just because you might not get cancer, it doesn't mean you're going to live a good quality life. I'd venture to say that almost all life-long smokers are going to have inferior quality of life at some stage. They'll be less efficient at getting oxygen into their blood, so they're going to struggle more with exercise and even general living like climbing stairs (eventually). Not to mention the risk of COPD and other diseases. Cancer is a major effect of smoking, but not as common as respiratory distress. Regards, --—Cyclonenim | Chat  23:40, 13 June 2010 (UTC)

I would expect that the curve of dose against cancer risk would be steep at first but then be less steep later. For example the increase in risk from shooting eleven rather than ten bullets at someone would be less than the increase in risk from firing 1 rather than zero bullets at someone. 92.15.14.150 (talk) 20:02, 13 June 2010 (UTC)

Side note

Above I've mentioned the risk of COPD and other lung diseases as a result of smoking. I wonder if smoking can cause a linear decrease in respiratory health, and are there any studies that show this? Regards, --—Cyclonenim | Chat  23:44, 13 June 2010 (UTC)

Primary afferent axons

So according to the textbook there's a different thermal threshold for different primary afferent axons fibres. How does it actually work? I don't really understand it. -Tactile.ab (talk) 11:12, 13 June 2010 (UTC)

In the same way that you have no problem understanding how there can be a temperature threshold for any type of nerve fiber, why can't you extrapolate in your mind that different nerve fibers can have different temperature thresholds. I think that's simple enough, unless you had something more specific. DRosenbach ^{(Talk | Contribs)} 13:47, 13 June 2010 (UTC)

It's a pretty complex question. The temperature dependence of action potentials is mainly a function of changes in the kinetics of voltage-gated sodium channels, but the point at which failure occurs is determined by the way these channels interact with other factors such as axon size and myelination. The failure point is especially different between myelinated and unmyelinated axons, because of their different mechanisms of conduction. The literature on this topic gets pretty technical, but if you are interested, here and an old paper that gives some of the basic phenomenology. Looie496 (talk) 16:40, 13 June 2010 (UTC)

Thanks! The link was quite helpful. -Tactile.ab (talk) 05:27, 14 June 2010 (UTC)

Ruth's Chris Steak House

They advertise that they cook their steaks at 1800°F -- firstly, what sort of oven are they using and secondly, I would think that such a high temperature would destroy the meat. Obviously it doesn't, but if anyone can explain, that would be great. DRosenbach ^{(Talk | Contribs)} 13:45, 13 June 2010 (UTC)

Responding to the second question first, I'll ask you one of my own — if you put a roast in a 400°F oven, when do you take it out? (Hint: it's not when the entire roast is 400°F throughout, now is it?) High external temperatures mean that you get some tasty, tasty chemistry going on at the surface of the meat (giving it that delightful 'sear', with all of its flavors and textures; depending on the meat, rubs, and glazes, there's going to be some combination of Maillard reaction, caramelization, and breakdown products of myoglobin). You only want to do that for a limited time — a long, dry heat will suck all the moisture out of your cut of meat and leave you with leather. Getting the sear (and the rest of the cooking) right is going to be a balancing act between time and cooking temperature. TenOfAllTrades(talk) 14:06, 13 June 2010 (UTC)

(ec)This is the temperature of the outside of the steak (which will char) but obviously the middle will see nothing like this temp. You can get this kind of temp with a pottery kiln; presumably they just put the meat in and out of one for enough time to the centre to get to 120C or so. Not vastly different to a barbeque I would say--BozMo talk 14:09, 13 June 2010 (UTC)

I hope you meant 120°F, not 120°C — or I'm not ever coming to one of your barbecues! TenOfAllTrades(talk) 14:15, 13 June 2010 (UTC)

... and I hope you really did mean 120°C or I wouldn't eat it! Dbfirs 14:52, 13 June 2010 (UTC)

120°C is way above water's boiling point — by the time the center reached that temperature, you would have driven off virtually all of the water from the meat. The inside would be leather, and the exterior would be burnt to a crisp. The interior of a solid cut of meat should be relatively free of pathogens; presuming that it has been handled properly, the nasty stuff is generally on the outside. (That's why it's important to cook ground beef all the way through, and one of the reasons why you shouldn't go impaling your raw steak with a meat fork — and why your prime rib roast only needs to be cooked to an internal temperature of 120-130°F for a nice medium-rare.) TenOfAllTrades(talk) 16:00, 13 June 2010 (UTC)

Wikipedia says you want the interior to reach about 160-165F (71-74C). I agree that 120C would destroy your dinner. --Tango (talk) 19:23, 13 June 2010 (UTC)

Our article has some bad cooking advice, then — and its numbers are different from those in the linked source ([17], purportedly based on USDA numbers). 160°F is a good target for ground beef, which as I noted should be cooked through to a higher temperature. For a roast, pull it out of the oven at around 130°F to hit medium rare (give or take a few degrees, exact temperature recommendations will vary from one cookbook to another: [18]). Let it rest, covered, for twenty minutes or so; the internal temperature will rise another 5-10°F as the outer layers come into thermal equilibrium with the core of the roast. TenOfAllTrades(talk) 20:04, 13 June 2010 (UTC)

The numbers are consistent with those in the source. The source is more detailed, so obviously the summary in the article won't be perfect, but it's about right. --Tango (talk) 20:52, 13 June 2010 (UTC)

Yes, 120°C would make a very tough meal, but the fat should prevent it turning to leather. I'd rather eat that than risk 120°F because I don't like "rare"! I'll compromise on somewhere mid-way between the extremes. Dbfirs 20:57, 13 June 2010 (UTC)

I'll go out on a limb here and suggest that even the exterior surface of the steak never really reaches 1800°F (though it certainly gets quite a bit hotter than the interior, and quite a bit too warm for comfort). If you put your hand in a hot oven, does your skin instantly reach 500°F? TenOfAllTrades(talk) 14:15, 13 June 2010 (UTC)

Cooking at 1800° would be like putting meat in a hot fire. It would even be hot enough to melt salt (almost). --Chemicalinterest (talk) 18:39, 13 June 2010 (UTC)

Allium Care

I grew a patch of allium this spring. They bloomed beautifully and are now green. Structurally they add to the architecture of the garden, but should I remove the heads and let the rest of the greens die back, as in tulips, or can I leave the heads as well as the greens to die back? So far they are sturdy and add to the garden in their green state as much as in their purple and white.

Barb —Preceding unsigned comment added by 75.72.20.144 (talk) 14:57, 13 June 2010 (UTC)

I can only say that I would leave the whole plant until it dies down naturally, because I find allium seed heads visually atractive. Why not experiment and leave some so you can see what they look like? If you don't like them you can cut them down. --TammyMoet (talk) 17:04, 13 June 2010 (UTC)

Hi Barb, I've got to say alliums are lovely. I had a rummage round to try to find a trusty source (since I'm not at home with Mum's big collection of thorough books by D. G. Hessayon) and the closest thing I could find is this guide from the UK's Telegraph newspaper. The gist is that if you don't want them spreading, just make sure to dead-head them before the seeds disperse, but until then you're fine. If you don't mind them spreading, you don't need to do anything. This seems to be the advice on other sites I could find too. Happy gardening, Brammers (talk/c) 19:52, 13 June 2010 (UTC)

Dog whistles.

My new phone has a free App that simulates a dog whistle - the kind that is producing a short sound at a frequency higher than humans can hear - but within the range that dogs can hear. That much I understand.

But Scott (a black lab puppy - aged 6 months) has never been trained with a dog whistle...yet he reacts instantly and looks at me with head tilted to one side whenever I activate the thing. The software lets you set the frequency to all the way down to 80Hz - and if I whistle at 'normal' frequencies - one or two kilohertz - he totally ignores it.

Our article suggests that dog whistles can be used to inflict pain - but that seems hard to imagine at the pathetic volume that a cellphone speaker can produce (especially at what must be the upper limits it was designed to produce). Also, he doesn't seem to be distressed by this - his reaction seems more like puzzlement.

Why would Scott pay special attention to these very high pitched whistles and not the lower pitched stuff? Is there something out there in nature that his wolf ancestors evolved to react to?

SteveBaker (talk) 15:21, 13 June 2010 (UTC)

It may just be that it is unusual. He hears people whistling and phones ringing and other devices bleeping all the time and has learnt to ignore those because nothing interesting is associated with them. He probably hasn't heard a dog whistle before (since you say he hasn't been trained with one) so he is wondering what it is. --Tango (talk) 15:36, 13 June 2010 (UTC)

As to the pain I made an ultrasonic whistle once and was trying it out and couldn't hear a thing, but my mother came and complained about the noise and told me to stop it. Dmcq (talk) 16:06, 13 June 2010 (UTC)

That's unusual. Ability to hear high sounds usually diminishes with age - you should be able to hear it better than your mother. Of course, with only 2 people, the sample error is very high! (See The Mosquito for some more information.) --Tango (talk) 16:14, 13 June 2010 (UTC)

I don't think the answer to this is known, but it's interesting that rats and mice are known to emit ultrasonic vocalizations as distress calls -- that seems like something a dog might care about. Dogs also use high-pitched whines as distress calls, but they don't generally reach the ultrasonic range, so the relevance is unclear. Looie496 (talk) 16:51, 13 June 2010 (UTC)

Its thought that dogs evolved the ability of hear ultrasound for one of two reasons, according to Peters & Wozencraft, 1989; in Acoustic communication by fissiped carnivores. Pp. 14-56 in J. L. Gittleman, ed. Carnivore Behavior, Ecology, and Evolution, vol. 1. :

• To detect the ultrasonic cries of prey species (such as rodents, as Looie496 notes)
• Because newborn puppies communicate with their parents by ultrasonic vocalizations

In either case, you are probably hijacking instinctive neural circuits that your dog has tuned specifically to these wavelengths - which is why you are getting a behavioural response from him that regular whistles do not evoke. Whether your app might inflict distress is a matter of opinion, of course, but it might be worth noting that research facilities are very strict about the use of ultrasound within their animals houses. Largely because it could be distressful to rodent mothers who are caring for pups. Rockpocket 17:11, 13 June 2010 (UTC)

I am curious (and skeptical) that the cell phone has either the electronics or the acoustic capability to create true "ultrasonic". Even a desktop PC usually has a 44.1 kHz sampling rate, permitting a maximum synthesis of 22.050 kHz. But that's the software sampling rate. The hardware digital to analog converter, especially on a mobile phone, may have an even reduced range. The physical transducer inside the speaker might have a frequency response as poor as 5 or 10 kHz (these things are bargain-basement cheap devices). It's plausible that if you have a high-end phone designed to play music, it might have a full audio capability up to 20 kHz - but even that isn't "ultrasonic," so how exactly is the device outputting a dog whistle tone? (I suppose if the tone is at 19 kHz, you might hear a low volume or nothing; while the dog does hear everything; but that would be a "borderline" case - many humans can and do hear 19 or 22 kHz tones). Nimur (talk) 18:03, 13 June 2010 (UTC)

Don't forget about harmonics. Ariel. (talk) 19:17, 13 June 2010 (UTC)

According to our article, dog whistles generally use frequencies in the range 16-22 KHz. Looie496 (talk) 19:23, 13 June 2010 (UTC)

Well, it works! Either I'm lying about not being able to hear it - or my dog is telepathic! The software ("Dog Whistler" 1.2 for Android by Mobeezio) claims to produce sounds from 80Hz to 21.9kHz - with a default at 16kHz. Some people can hear 16kHz - others can't (I can't) - but even 21.9kHz works for my dog - and not may people can hear that. SteveBaker (talk) 00:46, 14 June 2010 (UTC)

I guess you might be irritating some humans, too - many can hear tones up to those frequencies! The Mosquito operates at 17 kHz, and claims that most adults don't hear it - but I've played around with audio and I know I'm able to pass a double-blind test at 19 kHz and higher. Nimur (talk) 01:08, 14 June 2010 (UTC)

(EC)Actually most modern desktop PCs would support at least 48kHz (since it's used by most DVDs and many other digital video sources). And HD chips are getting rather common probably helped by things like Intel's HD Audio iniative [19] meaning even cheap motherboards will often have a HD audio chip supporting at least 96 khz and probably 192 khz. Of course there is little benefit to humans from these high frequency ranges as ABX tests usually show. However the HD audio chips may be better in general. In terms of mobile phones, the teen buzz and similar rings tones (The Mosquito#Teen Buzz ringtone) have shown that many perhaps even most mobile phones are at a minimum capable of producing frequencies high enough that many adults can't hear them. (You can get different tones and test them and some fairly high frequencies seem to work but of course it's difficult to know what frequency the phone is actually producing without some sort of accurate recording/monitoring.) And these even seem to work with MP3 and I think AAC compressed versions tend to work although these aren't generally designed to keep such high frequencies well AFAIK. Bear in mind of course we aren't talking about accurate musical reproduction just some sort of noise sufficient for a listener to hear. (I tried it myself once on my cheap Panasonic VS2 and it did work, I did try a variety of frequencies up to about 21khz but I can't remember the cut off point where someone I tested it on was able to hear something, the lowest age was about ~21 so probably not the ideal test.) Nil Einne (talk) 01:22, 14 June 2010 (UTC)

Nuclear fusion physics and tokamak reactor design: from the ground up.

Assuming that a layman with 'high-school' level scientific knowledge wished to fully understand the complex physics underlying a tokamak fusion reactor, and had years in which to do so, what would be the essential building blocks of physics necessary to begin the long journey upward? An image that springs to mind is a pyramid of square blocks, each successive level allowing advance to the next. Another assumption (possibly mistaken) is that a full physics degree would involve units and modules not relevant to the specific subject of desired study. I emphasise that this is not a question regarding nuclear fusion itself, but rather an epistemological question about the long itinerary of subjects a student would have to follow to arrive at the final goal.

149.170.241.66 (talk) 19:08, 13 June 2010 (UTC)

To understand this stuff quantitatively, you will need a thorough base in electromagnetics, chemistry, plasma physics, atomic theory, and a healthy dose of nuclear physics. To support the quantitative understanding of these scientific concepts, you will also need several years' of mathematical theory beyond "high school" level - this typically means several courses in calculus and differential equations, a good level of linear algebra, and some fourier theory or complex analysis will help with the plasmas and the atomic theory. Amazingly, this is what you will study if you obtain an undergraduate degree in physics. (About the only other stuff required for a physics degree - material that would be "peripheral" to your fusion goal - would be one or two courses in "classical mechanics" - while not directly relevant to fusion, this knowledge and the associated techniques, like Hamiltonian mechanics, are essential to understanding the more sophisticated particle interaction theories that work at quantum scales). If you want to further study fusion, you will probably continue with several graduate courses in plasmas, electromagnetics, and (finally), material specifically on nuclear fusion. If you want to build Tokamaks, it will help to throw some engineering courses in the mix: a power electronics course, a few mechanical engineering courses (specifically, learning about vacuum systems); several engineering thermodynamics courses, and so on. Nimur (talk) 19:52, 13 June 2010 (UTC)

formaldehyde

is formaldehyde a endocrine disruptor or reproductive toxin —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 21:02, 13 June 2010 (UTC)

Formaldehyde isn't usually classed as a reproductive toxin, that is, is doesn't have any specific effects on the reproductive system. However it is both toxic and carcinogenic, so it could cause reproductive problems through either of those mechanisms. It's hard to give a firm answer on the question of endocrine disruption, because there isn't any agreed "test" or "standard" for an endocrine disruptor. However, it isn't the sort of compound that one would expect to be an endocrine disruptor, and I've never seen anyone suggest that this is a significant hazard for formaldehyde. Physchim62 (talk) 22:15, 13 June 2010 (UTC)

Body hair

I saw an advertisement saying that removing body hair in young people at puberty can prevent its regrowth later in life. How is this done? Why does it work? It is without the use of chemicals or lasers to kill the follicles, of course. 76.229.192.126 (talk) 20:45, 13 June 2010 (UTC)

Is this some new technology? None of the conventional methods would prevent regrowth without destroying the follicles. Our article on Hair removal mentions lots of methods and includes some warnings. Dbfirs 21:02, 13 June 2010 (UTC)

You can't prevent hair growth without destroying the follicles. They constantly produce hair, so if they're live cells then they'll continue to do so. All methods of permanent hair removal work on this principle: they destroy follicles. Regards, --—Cyclonenim | Chat  23:46, 13 June 2010 (UTC)

Rule VI of Life "Never believe anything you see, read or hear in an advertisement". Richard Avery (talk) 07:12, 14 June 2010 (UTC)

Ploughing a field with dogs

Has any culture ever used working dogs to pull a plough in a farming context (not a snow plough)? Just saw a sled being pulled by huskys on TV and I thought about this for some reason. Thanks. --95.148.105.80 (talk) 23:29, 13 June 2010 (UTC)

consider the size of horse and dog hind leg

It's really not possible. Dogs aren't big or strong enough by a lot. See the image - and the difference is muscle volume.

77.86.111.26 (talk) 23:44, 13 June 2010 (UTC)

The nearest thing is Dogcart (dog-drawn) 77.86.111.26 (talk) 23:48, 13 June 2010 (UTC)

It takes a lot more force to pull a plough through earth than to pull a sled across snow: a single human can pull a loaded sled across snow, but it takes a team of humans to pull a plough! Physchim62 (talk) 02:14, 14 June 2010 (UTC)

Dogs are not as strong as horses (or mules, or oxen) but neither are humans, which have pulled plows when stronger animals were not available, as in 19th century and earlier wartimes or periods when draft animals were not readily available [20]. Multiple dogs would be required to exert the tractive effort of a draft animal. and small carnivores may be less efficient at pulling plows than large herbivores [21]. Edison (talk) 04:46, 14 June 2010 (UTC)

June 14

Synthroid versus Armor thyroid

Synthroid synthetic thyroid replacement hormone is dosed in micrograms. Natural thyroid, such as Armour thyroid, produced by Forest Pharmaceuticals, made from porcine thyroid powder, is dosed in grains. Are there published equivalencies of efficacy of Synthroid micrograms versus Armour thyroid grains? How many grains of Armour would be equivalent to 100 micrograms Synthroid? Edison (talk) 04:07, 14 June 2010 (UTC)

Rifling and slower bullets

If I understand the rifling article correctly, all sides of a rifle bullet continuously scrape against the inside of the barrel, along the entire barrel length; while in a smoothbore weapon, the bullet (or ball) is smaller than the internal diameter of the barrel, and the bullet basically ricochets a few times against the inside of the barrel before it exits. I assume the hugely larger amount of friction in the rifle would slow down the bullet a lot, compared to the smoothbore; though I might see how in a smoothbore weapon, the bullet wouldn't "capture" as much force from the gases expanding from the gunpowder explosion. So, in "equivalent" rifle and smoothbore weapons, how much slower is the rifle bullet immediately upon exiting the barrel? Comet Tuttle (talk) 04:23, 14 June 2010 (UTC)

I'm not sure a rifle would be slower. If the bullet continuously scrapes against the barrel, that means that the pressure wave from the explosion propelling the bullet stays entirely behind it, propelling it more efficiently. — DanielLC 05:59, 14 June 2010 (UTC)

Our article on internal ballistics has a section on energy transfer during the transit inside the barrel. Rifle rounds engage - they actually squish/expand/melt into the bore rifling, forming a metal-to-metal seal that is extremely precise. Virtually all of the pressure-volume work is transferred to the round. (Of course friction does cause some loss to heating the barrel, but this is much smaller in magnitude compared to the energy lost if there is a gas-escape from an improper round/barrel seal. It's hard to compare, because few rifles have an equivalent smoothbore version. Even those few firearm models that could be equipped with either barrel type are not "exactly" the same between rifled and smoothbore versions - the cartridges, calibers, propellant charges, and so on are different. Even the makeup of the bullet is different, because the materials and alloys that allow a rifle round to expand and engage the grooves are useless in a smoothbore. Typically, though, rifle rounds are faster than smoothbore rounds - this may be a design consequence, and not an effect of the rifling. Because rifle rounds can be more accurate and more stable in flight, it is possible to design them to fire faster, imparting more energy and resulting in more effective terminal ballistics (stopping power, penetration, or other desired ballistic property). Nimur (talk) 06:05, 14 June 2010 (UTC)

Why did SI standardize the mole?

The SI unit of amount of substance is the mole. But there existed already an SI unit, the joule per kelvin, J/K, as the Ideal gas law relates amount of substance n to pressure p, volume V and temperature T by pV = nRT where R is a constant conversion factor, the gas constant. If n is measured in mole then nR is measured in J/L. So I wonder why the mole is standardized as an SI unit? Using the J/K as unit for amount of substance would simplify all formulas involving R. Bo Jacoby (talk) 07:20, 14 June 2010 (UTC).

THe Ideal Gas Law only relates to gases though, and as most substances manipulated or calculated aren't gases, that wouldn't be all that much use. --John (talk) 07:29, 14 June 2010 (UTC)