Wikipedia:Reference desk/Archives/Science/2007 September 26

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September 26

What is this phychological behavior called?

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I read something a while ago about a certain psychological quirk that can be used to get a feel for a person's personality or behavior. In essence it goes like this: Propose a hypothetical question "Do you think that most people do <x>?". A person who does <x> is more likely to answer Yes to that question. E.g. A person who cheats on their taxes is more likely to answer yes to "Do you think most people cheat on their taxes?", and so on. This tendency has a name... anyone know? The context I read it in was that companies would ask similar questions of prospective hires relating to behavior on the job (stealing from the company, harassing other workers, etc...). Thanks! Arakunem 00:29, 26 September 2007 (UTC)

leading question,implicit assumption, begging the question ? 87.102.23.3 01:36, 26 September 2007 (UTC)

None of those seem relevant here. —Tamfang 15:32, 30 September 2007 (UTC)

Of course, honest people who are pessimistic about their fellow humans will also answer that way. (Just more bad news for us pessimists, apparently the world is against us.) StuRat 01:38, 26 September 2007 (UTC)

Projection? --71.175.68.224 03:32, 26 September 2007 (UTC)

I think you are looking for one of the cognitive biases, probably False consensus effect fits best, if you go through the List of cognitive biases you may find one that fits better. Vespine 06:44, 26 September 2007 (UTC)

Cognative bias! That was the term! *Awards Vespine one pie* And thanks to all who responded! Arakunem 13:23, 26 September 2007 (UTC)

Sorry, but "cognitive bias" is a more general term. As the existence of a "list of cognitive biases" suggests, there are many of them. You asked about a specific one. --Anonymous, 22:51 UTC, September 29, 2007.

Runaway Global Warming

How far are we from runaway global warming? Twenty years? Ten years? Is there any way to find out? 210.49.155.132 13:16, 26 September 2007 (UTC)

The most reliable way to find out is to wait and see. Otherwise, the only answers that exist are suppositions ranging from "never" to "it's already started", and there is no one agreed-upon best estimate. — Lomn 13:43, 26 September 2007 (UTC)

That's a pretty silly answer. You might as well throw out all prediction in science and anything else. You make it sound like all suppositions are equal, like they are all equally valid guesses, even though some are no doubt based on better reasoning and better evidence than others. --24.147.86.187 13:49, 26 September 2007 (UTC)

I think his point was that there is no consensus even among both "sides" of the issue. Arakunem 14:03, 26 September 2007 (UTC)

I believe there is a general agreement among scientists that human activities have affected world climate and will continue to do so (with the exception of a few scientists, mainly paid off by oil companies). There is not, however, a consensus that we will reach a point where climate change will accelerate out of control. Some scientists think it will, but many others think we are only likely to see a steady, reversible increase in global temps. So, not only is there no agreement when "runaway" global warming will occur, but even that it will occur. StuRat 14:23, 26 September 2007 (UTC)

I agree - "We don't know" is the best answer. There are several positive feedback effects (which we discussed earlier - and presumably triggered this question):

• Albedo reduction due to ice sheet retreat is clearly already happening. Both polar ice caps are shrinking ever faster so we are already in 'runaway' ice sheet shrinkage. The North pole will become completely open ocean within just a few years. The Northwest passage is already much more open to shipping than it once was and the geopolitical consequences of this are already unfolding (the Russians are starting to claim more terratorial waters on various tenuous grounds so that they may 'own' the rights of shipping to travel that way - the Panamanians have started a panic move to widen and deepen the Panama canal in order that they don't lose business to ships taking the NorthWest passage). Polar Bears and going to go extinct within our lifetimes.

• The terrifying prospect of deep ocean frozen methane melting has not started yet - so that's not yet a problem. If it does happen, we're in for a very rough ride.

• Sudden ocean current reversals are also 'threshold' events - but they don't affect global warming - only local weather patterns...however, there is a point of no return with those things too. If a major ocean current 'flips' and runs backwards, formerly temperate northern countries could be in deep trouble - and places that are currently frozen wastelands would become nice places to live. Not good for Europe - not so terrible for Canada...for example.

• There are other nasty ones that are more theoretical than real - the idea that when the air temperature increases, more water evaporates from the oceans, which has two side effects - one is that you get more cloud - which reflects sunlight and actually helps to keep the planet cool - but the other is that water vapour is in itself a greenhouse gas - which makes the planet hotter. Which of these effects 'wins' is not an easy question to answer.

• There no doubt that increased CO2 and heat levels along with shifting weather patterns will do serious things to plantlife. Some species will do better some will do worse. We don't really know whether the ones that will do better will be able to convert CO2 to Oxygen at a higher or lower rate than the ones that will go extinct. Hence we MIGHT get lucky and get some help from new plant distributions - or we might trigger another positive feedback that would make things yet worse still.

• Rising sea levels are not a good thing. Ocean is generally darker than land - so again, the higher sea levels rise, the more lighter-coloured land disappears under darker coloured water - and the more heat the planet absorbs - so the more ice melts and cooler water undergoes thermal expansion which makes yet more sea level rise. The precise rate at which this feedback loop kicks in depends on the exact shape of the land - how much land is covered by a 1 meter sea level rise (and how much the albedo changes as a result) is hard to measure exactly.

But in the end, it is precisely that these effects are NOT known well that is the cause of the most worry. If we knew exactly what the consequences of our behaviour was, we could nail down exactly the costs and benefits of every action we took. However, we don't know that - and the science is just WAY too difficult. A prudent civilisation would say that the risk of a total global catastrophy is significant - and the consequences are about as serious as anything we could imagine - so we have to act quickly to minimise any further change. But we're not a prudent civilisation - so we're guaranteed to be in trouble - it's just that we don't know when exactly. SteveBaker 14:49, 26 September 2007 (UTC)

Runaway global warming obviously hasn't happened yet. It would seem logical that it would have to be hotter than it's ever been in order to start. Wasn't the earth originally part of the sun? — Daniel 23:07, 26 September 2007 (UTC)

Er - well, I guess you could say that - the earth formed in orbit around the sun from dust and such like and was much, much hotter then - but a lot has happened between then and now. It's not a reasonable comparison - the earth didn't have plantlife or even oceans back then. It's possible that runaway global warming has happened before - but then been reversed by (for example) a large meteor smashing into the earth and throwing up a large enough blanket of dust into the atmosphere to block the suns rays...that would chill temperatures significantly - perhaps dropping the planet back into a more stable, lower temperature. So I don't think that if the world was baked by global warming that it would stay that way forever - but even if it just stuck that way for a few centuries, it would be a total disaster. SteveBaker 01:54, 27 September 2007 (UTC)

If the combined effects of an atmosphere containing huge amounts of CO₂ and the total absence of reflective ice caps aren't enough to so much as keep the world from cooling, what could possibly make it heat at that point? Was there some cooling effect I don't know about? Am I combining things that didn't occur at the same time? I know they didn't all occur when the earth was formed, but where they ever all there at once? The probability of a large meteor impact, volcanic eruption, or other major cooling event occurring while it is still possible to save the environment is extremely low, implying that if something like that happened, all the runaway global warming did was rise the temperature to a different equilibrium. — Daniel 03:42, 27 September 2007 (UTC)

Oh - yeah - OK. Well back then the earth had no water - water vapour is a tremendous greenhouse gas. With no water vapour in the air, the earth cooled off over millions of years. Water only arrived much later (from cometary collisions) - and by that time the earth was much cooler. But there have been huge changes over that time - vulcanism was much greater back then. The atmosphere was much less dense. There are way too many differences between then and now...and we don't have millions of years! SteveBaker 23:23, 27 September 2007 (UTC)

Clearly, global warming has been happening since the last century, to the tune of less than one degree Celsius during that time. No measurements so far demonstrate anything definitely abnormal. There's an argument going on about how much of global warming is man-made, and the only answer almost everyone agrees on is "some of it". The consensus ("most of it") may or may not be right. There are some astonishing debates about the Medieval Warm Period, and a lot more work needs to be done on the variations in solar activity. As a non-scientist who tries to read the news on all this intelligently, I wouldn't say "Wait and see what happens", but I do say "Let's see what the scientific consensus is in ten years' time, and panic only a little for now". One thing which amuses me is that only thirty years ago, many climatologists were predicting a new Ice Age. If we had to choose between the two, I'd go for the global warming. Xn4 06:08, 27 September 2007 (UTC)

30 years ago, we didn't have global warming - the climate was within a normal range. The historical CO2 level (from a few hundred years ago) was around 270ppm. 30 years ago, it had risen to 310ppm - a significant rise to be sure - but not enough to be a problem. This year, we're up at 390ppm. So 30 years ago, the excess CO2 was around 40ppm - over the last 30 years, the excess has gone up to 120ppm above historical levels. Worse still, the annual increase in CO2 in the 1970's was only perhaps 8ppm per decade - now the rate of increase is around 15ppm per decade - indicating a dangerous exponential trend. The reason they weren't predicting a problem in 1977 is that we didn't HAVE a problem in 1977. Bear in mind that the natural annual 'swing' in CO2 levels is about 10ppm - seeing a difference of just 40ppm against that background swing wasn't a trivial matter with 1970's technology. Furthermore, we had only just started collecting routine CO2 level data back in the 1970's - so they didn't have much data to go on. Now we have 30+ years of accurate readings and (via ice cores and such) we have reasonably accurate data going back thousands of years. Now that we have the data - and the trend is much clearer, we can be very certain this time around. SteveBaker 12:41, 28 September 2007 (UTC)

Oh - jeez..."lets wait and see". That's *so* lame. Let's put our heads back under the blankets and hope it all goes away. That way we don't have to work hard and we can carry on driving our Ford Expeditions. GET REAL!

There is ALREADY an utterly clear scientific consensus - well over 95% of all scientists and over 99.9% of all atmospheric scientists agree that this is a problem that humans caused and humans have to fix if we don't want to trash the planet. You'll never get a better consensus on any topic than that. If you ask scientists whether black is white, 5% of them will argue about it. There are minor disagreements about the extent of the problem - but almost zero difference on what we have to do to fix it and when. IIRC, if we wait 10 years it's going to cost 100 20 times as much to fix (according to that British government paper which I can't find right now, the Stern review) - if we wait 20 years, we're doomed.

As for "nothing abnormal" - let me give you a simple thought experiment that even you can do. It is VERY clear that the North polar ice cap is going to disappear real soon now - check out photos of it over the last 10 years and that's utterly indisputable - look at the photos - you don't need a scientist to interpret them for you. That in turn will (for 100% sure) cause the extinction of the polar bears - if the average distance between ice-floes gets bigger than the distance they can swim, they will all die - and that's not going to take 10 years, it's going to happen in 5 years. Now, if this were a 'normal' event that happens every few hundred years, then how come the polar bears didn't go extinct the last time this happened? If this were 'normal' then Polar bears would not exist...and they do. So we know FOR SURE that if this has happened before, it was a VERY long time ago - certainly before the evolution of polar bears...which was also before mankind evolved from the great apes - before most of the other plant and animals that we know existed in their present forms. So if you call something that hasn't happened for millions of years 'normal' then we shouldn't worry about the total destruction of 95% of life on earth either - after all, that's what happened when the dinosaurs went extinct, that was 'normal' too. SteveBaker 15:25, 27 September 2007 (UTC)

British government paper = Stern review. DuncanHill 15:29, 27 September 2007 (UTC)

Thank-you! That's the one I was thinking of. As our article says: Its main conclusions are that one percent of global gross domestic product (GDP) per annum is required to be invested in order to avoid the worst effects of climate change, and that failure to do so could risk global GDP being up to twenty percent lower than it otherwise might be....I believe that was "Invest 1% now - or after 10 years of doing nothing it's going to cost 20%". Personally, I'd be very happy to give up 1% of my earnings every year to get this problem behind us. SteveBaker 17:43, 27 September 2007 (UTC)

To Daniel, not sure what you mean, but this might help: In the beginning (to paraphrase a rather well-known book) most of the heat on planets came from the planets themselves. Then they started colling down and over time the Sun became the most prominent heat source. For Mars, that was not enough and it cooled down too much. For Venus, it was too much and it got a runaway warming effect. But for Earth, the temperature of the porridge surface was 'just right' for life (as we know it) to evolve. There were some positive and some negative feedbacks, which caused the temperature (and other variables) to go up and down over time. So life had to be adaptable (which can be seen as a definition of life). But the time-spans were very different. Adaptable life needs a shorter life-cycle than the changes, so it can adapt. It's the survival of life itself (or, rather, species) that matters - nature doesn't care much about the well-being of individuals. Every now and then, however, a change was so quick (for whatever reason) that life on Earth barely survived. Luckily, there are also always tiny critters like bacteria that evolve very quickly and can survive 'extremes' because they found a niche somewhere where conditions are uncommon. The 'new equilibrium' you talk about would then have been one that was more like those previously uncommon condition for some of these critters, in which they could thrive. So then life 'rebooted' and re-evolved from whatever survived. DirkvdM 09:38, 27 September 2007 (UTC)

To Xn4: 'just one degree' is a whole lot for global (average) climate change, especially for such an extremely short timespan (such global changes usually take place over (hundreds of) thousands of years). Don't forget that just a 10 C rise can wipe out most life on Earth. As for that ice-age, as Steve pointed out, a local ice age is just possible. In general, the fact that we don't know what might happen is one of the scariest aspects. But we do know there will be some effect.

As for the effect so far being small, consider this. We have to rule out variations on a smaller time-scale, the seasons, so we only get one measurement per year (that year's average). So over the last century, we've only had 100 measurements. For scientific certainty, that is not a lot. So if we do get (near) certainty that a change has taken place, then the reason must be that there is a strong effect. With this in mind, look at this page of the Dutch meteorological institute KNMI. The table at the top left shows the ten hottest years measured in the Netherlands since 1901 (the one below it shows the coldest years). All of those fall in the last 18 years. The chance of one such hottest year falling in that period is 18/106 = roughly 1/6. So the chance of throwing a 6 with a dice. So what is the chance of throwing 10 sixes in a row? (1/6)¹⁰ = 1/60,466,176 (there's a slight inaccuracy there, but that barely affects the end result). So there's a chance of one in sixty million that nothing is happening. For me (and science) that constitutes more than sufficient 'certainty' that something is going on. Such extremely strong certainty (given the subject at hand) with so few measurements means there must be a very strong and rapid effect. Given Earth's extinction history, we should do everything in our power to counter that.

Note that even if human actions weren't the cause, this would be reason to do something very fast. But lucky us, we are probably the major cause, so we've got a very simple solution - just stop doing what we're doing. Or at least reduce it as much as we can. Or at least try. But we're not even doing that. We must be very stupid. DirkvdM 10:01, 27 September 2007 (UTC)

That's true (and often missed by the critics). Even if this was caused by volcanos, forest fires, cow farts, solar cycles or whatever other 'natural' theory - it's happening too fast for evolution to keep up with it and life on our planet will change drastically - perhaps too drastically for humanity to survive at it's present level of comfort. Sure, eventually everything will evolve to cope with the new conditions - but it took us 4,000 years to evolve lactose tolerance - and quite a few people aren't there yet...so expect to have a rough ride for a few thousand years before we get over this one.

So even if the causes are natural, we should fight it. A massive meteor bearing down on us would also be a 'natural' event - but that doesn't mean we shouldn't deploy spacecraft and nuclear weapons to deflect it. If indeed global warming were a natural event, we should count ourselves luck that we can fight nature by deliberately cutting back our CO2 usage.

However, if you look at a graph of historical CO2 levels (as measured in tiny air bubbles buried in ice cores from the antarctic for example) and compare them to average global temperatures (from historical weather records and things like tree rings) - you find that they match up extremely well - and if you compare CO2 levels to our consumption of oil, coal and natural gas, you find that those curve match up extremely well too. Does one cause the other? Well - as DirkvdM so elegantly demonstrated - the odds are millions to one against it being some other cause. The problem is that most scientists are trained not to say that A causes B until they have actual 100% proof - and this is only 99.999% proof - which is why there too many of us have been cautious about speaking out about it. SteveBaker 17:43, 27 September 2007 (UTC)

To DirkvdM: You wrote "To Xn4: 'just one degree' is a whole lot...". Those weren't my words, which were (see above) "less than one degree Celsius". Wikipedia's global warming article says that the average measured global air temperature near the Earth's surface has risen 0.74 ± 0.18 °C during the last hundred years. However, in the US (where records of temperature are probably as good as anywhere and better than most countries) the accepted figure is only 0.3°C. AccuWeather says the figure worldwide was 0.45°C. The grandiose Intergovernmental Panel on Climate Change (IPCC) in its last report took the bidding up to 0.6°C, Stern implies a higher figure, Wikipedia has 0.74 ± 0.18°C, and you now tell me (claiming to quote me) that it is 'one degree'. Where does this inflation end?

As I read these debates, much of the hysteria about global warming is based on misquotation and evasion of the evidence. The IPCC produced a report in 1996 which included a graph showing that the Middle Ages were warmer than the present day. Its second assessment report in 2001 had a new graph which made the Medieval Warm Period disappear, by a crafty use of averaging and by silently leaving out the data showing the medieval warm period. (That material went into a file called 'Censored Data'). If the case is so overwhelming, why do people behave this way? Xn4 02:23, 28 September 2007 (UTC)

Ok, let's say half a degree then. Still a whole lot for such a small time period. Like I said, climate change usually goes very slow by human standards, more in the order of thousands of years and just a few degrees over such a time period spells disaster for life on Earth (it has in the past). Half a degree in a mere century is a hell of a lot. But the IPCC says 0.74 C (which is where Wikipedia got that figure from of course). Who is misquoting now? :) And that is worldwide, not just the US. That's what the IPCC is about; collecting findings of scientists from all over the world, including the US. No matter how good your equipment is, having it in just one country is not going to tell you much about world climate. You need results from weather stations all over the world. And of course findings change over time as more data comes in. So far, the predictions (from previous assessment reports) have mostly turned out to be too conservative, especially concerning the melting of the Arctic ice cap.

Do you have a source for the 'censored data' bit? Preferably one from outside the US, because that's where all the dissent seems to come from. And have you had a look at that graph in the Mediaeval Warm Period article you linked to? Note that that warm period is a thousand years ago and it is a slight bump, as opposed to the sudden spike in our time period. DirkvdM 06:10, 28 September 2007 (UTC)

Yep - I agree. Just because one report did something 'iffy' doesn't allow you do dismiss the dozens and dozens of others that come to the same conclusion. 99.99% of atmospheric scientists agree...this is not a hotly debated topic amongst experts. Essentially all of the dissent comes from non-expert people who desperately wish this wasn't true and have decided to take the 'ignore it and hope it'll go away' approach. Sadly, the media (who love dissent and disagreement) are giving equal air time to the 0.01% of scientists and the other 99.99% - giving an entirely biassed view of actual scientific opinion. SteveBaker 11:27, 28 September 2007 (UTC)

Also, oil is a multi trillion euro industry. It would be surprising if that extremely powerful industry didn't throw it's weight around, such as by bribing funding dissenting scientists and reporters. DirkvdM 14:50, 28 September 2007 (UTC)

I'd like Xn4 to respond to my argument about the Polar Bears (above). SteveBaker 11:27, 28 September 2007 (UTC)

Hi, Steve. You said "Polar Bears and going to go extinct within our lifetimes." I can't say it won't happen, I'm not a climatologist, I'm just a lay sceptic, but it seems to me a very categorical prediction, considering how little we know about several key factors, such as the unexpected variations in solar activity over the past fifty years. We can say that the polar bears survived the medieval warm period, which for hundreds of years saw higher temperatures than we have now (and which has been all but vanished from the graph above). You said "The terrifying prospect of deep ocean frozen methane melting has not started yet - so that's not yet a problem. If it does happen, we're in for a very rough ride." As I understand it, deep water temperature measurements haven't changed at all since the 1930s, and sea temperatures generally have not so far responded to any of the predictions made by climatologists. If and when they do so, it will surely be more rational to treat those predictions as having some authority. Xn4 19:42, 28 September 2007 (UTC)

You're a layman. We are laymen. (Goo-goo-ga-choo.) So who should we trust? What about scientists? Better still, what about all the best scientists in the world putting their findings together? Hey, we've got that: IPCC. And they have looked into the solar activity and concluded that it's probably a minor contributor, if at all. Basically, you're saying you only believe scientists when it suits you. Similarly, first, you come up with a link to an article, and then when I use that too, you dismiss it.

What do you mean by 'sea temperatures haven't responded'? Do you mean they haven't risen? Then what do you think has been the major cause for the rise in sea levels? You really should do more reading on the subject before you declare the world's scientific community nuts. Anyway, now you know, so will you, like you said, "treat those predictions as having some authority"?

I've added another graph. Note that the mediaeval bump you make such a big deal of is just the last of many. Its the spike at our present time that's worrying. Note that on that time-scale it would be a vertical line, which I suppose is the reason the present temperature is marked with a arrow, showing what the average temperature was in 2004 - well above what it was 8000 years ago, despite the fact that it has been dropping gradually ever since - until about 100 years ago. DirkvdM 10:44, 29 September 2007 (UTC)

DirkvdM, would you please try harder to stay calm and avoid hurling insults? You ask "What do you mean by 'sea temperatures haven't responded'?" Please see what I said above - "...sea temperatures generally have not so far responded to any of the predictions made by climatologists". If you disagree with that, please refer us to one such prediction which was remotely correct, instead of changing the subject to ask about the remarkably small rise in sea levels so far observed. That rise, by the way, is also hugely less over any period you care to name than the climatologists have predicted it would be. Look (for instance) at the predictions published ten years ago and compare them with the out-turn. In my view, there is no reason to award a high level of trust to the forecasts of people whose record so far is that they have got nothing right, and I include the IPCC in that. And when it comes to graphs, they are no more than a simplistic way of presenting sets of figures. In this area, I don't blindly trust any of the figures produced by anyone: on both sides of the debate, they all come from people with an agenda. Xn4 22:49, 29 September 2007 (UTC)

You can be skeptical and still strongly advocate for CO2 emission reductions...you simply have to approach this with cold rational logic.

Even if you are skeptical of the science you have to agree that there are basically four ways this can play out:

1. If the majority of climatologists are right and we don't act within about 10 years - the consequences are vast - unrecoverable - disasterous - end-of-the-world things - and doing the best we can to minimise the damage costs 20% of GDP - our children and grandchildren go through hell - and the planet is a very different place for our great grandchildren.
2. If they are right and we act quickly - we lose some species, things are not good - but we survive. It costs us 1% of GDP and humanity comes away bruised and chastened - but the planet lives.
3. If they are wrong and we don't act - then nothing much happens except a few scientists are very embarrassed.
4. If they are wrong and we go ahead and cut CO2 emissions because we believe them - then we waste 1% of GDP cutting back on fossil fuel consumption and upgrading our infrastructure. This would be a fairly serious matter - but not disasterous by any means. As a side-effect we'd have dramatically cut fossil fuel consumption - and that's a good thing for other reasons (not relying on overseas oil from countries we'd prefer not to deal with - not running out of non-renewable fuels - not putting other noxious substances into the air, cutting back on acid rain and ozone-destroying gasses).

This is a classic 'game theory' type of problem - and the solution to those is elementary mathematics that is totally beyond debate. You multiply the consequence 'score' by the probability for each outcome - and compare the results for the options you have before you. Whichever option gets the highest score is the one you should choose.

OK - let's run the numbers.

Let's assume (per User:Xn4) an ultra-skeptical 50/50 split of reliable evidence and assign global warming a probability of 0.5 of being correct.

Let's assign the consequence score purely on monetary outlay - ignoring the other losses to our planet. You wind up with consequence scores of -20, -1, 0 and -1 respectively (using percentage of GDP outlay) for the four outcomes.

You weight those by the probabilities - and (with a total-skeptic point of view) you have -10, -0.5, 0, -0.5 respectively. The average outcome of "Do nothing" is (-10 + 0)/2 which is -5 and the average outcome of "cut CO2 emissions immediately" is (-0.5 + -0.5)/2 which is -0.5. The game-theoretic response to the utterly devastating (1) outcome and the relatively mild (4) outcome is quite clear - you act as if the science is correct and you cut CO2 emissions. There is simply no contest.

The only way to rationally advocate doing nothing for another 10 years is to change the probabilities of the two outcomes and say that the probability that 99.99% of climate scientists being wrong is at least 20 times higher than them being right. That would be enough to balance the decision and allow you to rationally decide to do nothing. But really - is it at all likely that 99.99% of people who have devoted their lives to studying this problem have only a 5% chance of being correct?

But it doesn't end there. We only considered the cold, hard monetary cost. We didn't add in the somewhat nebulous cost of loss of biodiversity loss and the likely economic problems for some nations due to sea level rise. Those figures only make outcome (1) more expensive. We also have some benefits to outcome (4) that we decided not to take into account - so the cost score for (4) should be less than 0.5.

Redo the math with whatever price you put on the quality of life and now the final decision matrix favors "fix the problem immediately" to an even greater degree. In order for a rational person to advocate "do nothing" with a clear conscience - they'd have say that the probability of the science being wrong is 100 or 1000 times more likely than it being correct.

Do we really have a pile of evidence that global warming isn't true that is 100 to 1000 times more credible than the evidence that it is true? Wouldn't that massive pile of evidence convince at least a few more of the climatologists? I doubt that even User:Xn4 would be able to say that.

So advocating that we wait 10 years before we consider fixing the problem is beyond mere 'skepticism' - it's mathematically provable outright stupidity. QED. SteveBaker 02:45, 30 September 2007 (UTC)

That's a much better line, Steve, though (if I may say so) you're allowing unscientific rhetoric and numbers plucked out of the air to creep into that presentation. It wasn't I who "advocate[d] doing nothing for another 10 years" (see above), nor have I "declare[d] the world's scientific community nuts", as claimed by DirkvdM. There are a lot of climatologists out there who expect us to believe their every word when there is absolutely no reason to do so, and on this subject we have a lot of hysterical people and politicians. The gamble we're being asked to make a judgement on is the biggest game in town, and we need to approach it calmly and analytically. We know there is global warming, and also that there has been global warming in the past. Nothing persuades me that we know the causes of it yet, and there seems to be a real possibility that natural causes will prove to be the biggest factor. We shouldn't forget that "there was a slight downward trend of temperatures from the 1940s to the early 1970s" (see our global cooling article) which remains to be explained. Even if human activities are the main cause of climate change (which, for all I know, they may be) changing our behaviour dramatically isn't going to reverse the situation in a few years. As a sceptic, my question is whether we need to put our greatest efforts into objective scientific research or into huge economic and environmental gambles based on numbers we don't have. Xn4 04:20, 30 September 2007 (UTC)

Xn4 (three posts up), sorry if my last post came across a bit harsh. Then again, the 'harshest' thing I said was that you should do some more reading on the subject. And I certainly didn't insult you in any way, nor did I hurl anything. I just meant precisely what I said. Hell, I even started it with a little joke. Also, I'm totally calm. :)

Anyway, you ask about a prediction of 10 years ago that was even remotely correct. That would be the second assessment report then (halfway down this page). I haven't read that (only the science part of the fourth report, about which I wrote the Dutch Wikipedia article) but I can't find any predictions for today in there - most predictions in that report are about 2100 and 2050. It's more about what has happened than what will happen. It's a bit odd to ask me to come up with a prediction you claim to be wrong. You say the rise in sea levels is remarkably small, but if you live in the Netherlands then 17 cm so far (!) sounds rather scary. If this keeps up, we'll probably have to give up some polders this century. And then there's Bangladesh, who don't have our technology nor the money to buy it. Remember, what matters is not so much what has happened so far, but what indication that gives for the future - not just our future, but the next few centuries and millennia.

Steve, your game theory story is very good at illustrating the problem. But, as you also indicated, it's a huge oversimplification. Predicting climate change is next to impossible. Predicting the economic effects is like looking into a crystal ball. Also, if we lose 20% of our income then we're left with 80%. During my travels I've seen lots of people live quite happy lives on something like 10% of what people in the West have. But the major risk of climate change, which is oddly rarely mentioned, is the effect on agriculture. We've already seen major starvation as a result of unpredictable weather. And now the climate is starting to become unpredictable. And not locally, but worldwide. This is not a prediction but a risk we are running, the risk that we will have worldwide mass starvation. The chances are almost impossible to calculate, but the risk is huge. No matter how much money you have, if there is not enough food for everyone, people are going to die.

Xn4, you say there has been global warming before as if that makes it ok. Yes there has been, and look at the results. In its most extreme form, almost all life on Earth died, probably as a result of a 'mere' 10 C rise in global temperatures. But in recent history there have also been plenty of examples of weather not behaving like it used to, leading to massively failing crops, often as a result of a volcanic eruption, local phenomena that on occasion have had worldwide effects. This shows us how much we rely on predictable weather for our survival. So we really should be extremely careful about changing the climate permanently and worldwide. Actually, it should scare the shit out of us, irrespective of what the actual change turns out to be. That we know there is likely to be a change (hell, it has already started) but don't know how big or even of what kind makes it even scarier because we can't prepare for it and any responses will be ad hoc, meaning much of the damage will be done before we can do anything about it.

Where we should put our efforts (action now or more research first)is indeed a good question. But science needs data and those data come in very slowly (for any variable there is basically only one measurement per year due to the seasonal nature of climate). Finding that there already is an effect on climate (and therefore likely will be in the future) is a lot easier than estimating what, how much and where. That is simply going to take way too long so we have to do with what we know now, and that is that CO2-emissions (and methane) have an important effect.

Strangely, you call mitigation a gamble. But it's what we're doing now that is a gamble, so we should stop doing it as much as we can. That requires quite a change in lifestyle, but humans have proven to be highly adaptable. All that is needed is the will. We can change quite a lot about ourselves, but not our need for food. DirkvdM 08:48, 30 September 2007 (UTC)

More time or more space?

Which is there more of in the universe? More time or more space? —Preceding unsigned comment added by 146.95.224.67 (talk) 13:23, 26 September 2007 (UTC)

If Einstein is correct, then there is spacetime and the question holds no meaning. Otherwise, how do you propose to quantitatively compare space with time? — Lomn 13:44, 26 September 2007 (UTC)

I'm not sure the question makes sense. You can measure how much "space" there is, but you can't measure how much "time" there is. Even with space and time being importantly linked (spacetime continuum), I'm still not sure the question makes sense. Is there more or less time today than there was a million years after the Big Bang? One could make an argument (depending on your definition of "space") that there was less space then, but I don't think you could argue that there was less time then. Anyway, if you could "measure" them I'm not sure you could reasonably compare them, as they use totally different units and all (is there more height or more volume in me? It's a silly question too). --24.147.86.187 13:48, 26 September 2007 (UTC)

You question on the surface seems meaningless - eg "which is greater, 1 mile or 100 minutes?"87.102.32.155 13:57, 26 September 2007 (UTC)

Well, there might be an argument that the speed of light provides the appropriate conversion factor - so one lightyear of distance and one year of time might be considered equivalent. However, space is a three-dimensional thing and time is one-dimensional - so "more" is a tough concept. This is really an unanswerable one. Sorry. SteveBaker 14:28, 26 September 2007 (UTC)

If you believe space to be finite, and time to be infinite, then there's more time. --Sean 15:26, 26 September 2007 (UTC)

Here is a not entirely serious answer. Measured in natural units, the age of the Universe is roughly 8×10⁶⁰ Planck times, whereas the radius of the observable universe is roughly 2.7 × 10⁶¹ Planck lengths. So the universe contains about 3 times as much space as time. (Since Planck length / Planck time = c, I suspect this is not coincidence). Gandalf61 15:59, 26 September 2007 (UTC)

But you are comparing just the distance from one side to the other - the "amount" of space is it's volume surely? That would give you a volume of maybe 10¹⁸⁴plancklength³...but how you compare a volumetric measure to a time is still unclear to me. SteveBaker 16:40, 26 September 2007 (UTC)

How do you compare energy to mass? e=mc^2. You'll get the same answer if you use the system Gandalf used. Of course, I don't think the rest of that system has near as much evidence, but once you believe c^2, and therefore c, = 1, the rest isn't that much of a stretch. That system doesn't explain why people say gravity is the weakest force, as all four forces are equal to 1. — Daniel 22:57, 26 September 2007 (UTC)

Where does mass come into this? We're talking about volume aren't we? Nil Einne 15:36, 28 September 2007 (UTC)

Even if space and time are infinite, one could argue that space is "bigger" (depending on definitions of infinity). For example, if you spent every second counting (Countable set) a point in space (Uncountable set), you'd never finish. -- JSBillings 18:23, 27 September 2007 (UTC)

The amounts of points in space and moments in time are both cardinality of the continuum. The number of seconds in an eternity and cubic meters in an infinite volume are countably infinite. Either way, they're the same size. I'd use the second one as it doesn't say a nanosecond is as long as an eternity. — Daniel 22:43, 27 September 2007 (UTC)

chiral universe

It seems likely that the universe is chiral (I'm assuming that based on local observations)

Question: Are there any theories etc that look into or try to draw conclusions from or about this 'fact'. eg such as what about the other enantiomer, and how can I possibly distinguish which enantiomeric form it is (it seems I can't), or does this overall chirality have any meaning or consequences -

I'd also be interested in any philosophical analysis of the impications of this if anyone knows someone who has studied it. Thanks87.102.32.155 14:01, 26 September 2007 (UTC)

Does chirality (physics) shed any light on this ? StuRat 14:15, 26 September 2007 (UTC)

Not much as far as I can tell - the article deals with small things and I was thinking about the overall effect - thanks for your concern anyway.87.102.32.155 14:40, 26 September 2007 (UTC)

Thought the stuff about left and right handed fermions behaving differently looks interesting it's inherently flawed since this means that they are not true enantiomers. I'd be interested if someone can help to expand on this though.87.102.32.155 14:46, 26 September 2007 (UTC)

I'm no expert. Are you sure that the universe is chiral? I thought the effect was limited to biologically active compounds here on Earth? If it's the latter then it's easily explained. When the first lifeform (some kind of replicating protein/RNA thing) formed from random chemical events on early earth, it had one particular chirality. Since the whole of life on Earth is descended from that one original molecule, we all have to have the same chirality - and all biochemicals in our environment (which have formed from descendents of that first molecule) have to follow suite. If we're seeing similar bias in chiral molecules from space (eg carried here on meteorites) then perhaps this is evidence for panspermia - in which case a similar argument might apply on a wider scale than just the earth. If we're seeing that bias in clouds of dust and gas out beyond the solar system...then I'd start to suspect a subtle chemical bias.

I hope someone else can come up with a better argument because the effect is seen beyond the Earth, then this reply is rather unsatisfying! SteveBaker 14:22, 26 September 2007 (UTC)

Chirality means that a thing lacks a mirror plane of symmetry (or that inversion converts it to the other enantiomer) - that property isn't confined to organic molecules.87.102.32.155 14:42, 26 September 2007 (UTC)

Check out the earth (geology) or the solar system, or the galaxy - all are chiral as far as I can tell87.102.32.155 14:48, 26 September 2007 (UTC)

StuRat's on the right track, especially the Chiral theories section. Certain parts of the universe (i.e., forces and theories at the lowest levels) don't seem to be equally mirrored. We don't even need to look to the cosmos to see chiral non-organic stuff: some minerals form chiral crystals (the mineral itself may be achiral, but crystallizes into an asymmetric matrix—the direction is arbitrary, but each crystal is a single direction). IIRC, quartz and calcite are two like this, can't remember off-hand. DMacks 14:52, 26 September 2007 (UTC)

Thanks.. but that wasn't really my question. You are right that quartz (it is chiral) but equal amounts of L and R forms exist - so that doesn't come in here..

Also if you think about it - if a theory claims that two supposedly left and right handed forms of a particle interact differently with their own handed forms then they are not actually left and right handed forms - and not enantiomers (as I mentioned above with repects to fermions)87.102.32.155 15:10, 26 September 2007 (UTC)

If I could clarify my question - I assumed the universe the (whole thing) was chiral, and wanted to know more about a. its enantiomer (any theories about this) b. any theories that explain the overall chirality - ie a chiral beginning to the universe - an asymmetric start state, or a surplus of one form of 'chiral particles' over another. (As I understand it chirality cannot be created from an achiral state.)87.102.32.155 15:15, 26 September 2007 (UTC)

If you follow my link, you'll see that certain physical forces aren't chiral "by accident and the mirror image would be equally likely/valid/etc", but rather have a specific chirality by their very nature. That is, (apparently) in a mirrored universe, they wouldn't work the same. Going back to the original "how to determine chirality at all" (as opposed to "same vs opposite" relative to some other known), there was an interesting discussion of that here a few months ago. DMacks 16:34, 26 September 2007 (UTC)

It's an interesting link - but my worry is (I assume the fermions are a good example as any) - is that the two types of 'handed' fermions are not enatiomers - because the enantiomers would behave the same with respect to themselves. eg the article says F(r)F(r) interactions are not the same as F(l)F(l) (hope my terminology is obvious) - but if this is the case then in a 'mirror' world F(l) does not become F(r) because they are not enantiomers. So the description 'left handed fermions' is erroneous.

Please explain more if I've missed something else, .. (apologies if I'm picking up on the wrong topic)87.102.32.155 18:50, 26 September 2007 (UTC)

I might be getting a little confused - if a particle is intrinsically chiral (no problems here) then in a 'mirror world' it has the opposite chirality just like everything else, and so the two 'mirror worlds' are indistinguishable from an internal frame of reference.87.102.32.155 18:58, 26 September 2007 (UTC)

According to quantum physics, the universe isn't deterministic. If there is any randomness in a symmetric system, asymmetry can be created. For example, make a symmetric pattern of dots on a grid, then move each one in a random direction. Chances are, it's chiral now. By the way, how can you tell the universe is chiral from local observations? How do you know there isn't a mirror earth in a mirror galaxy on the other side of the solar system? — Daniel 22:47, 26 September 2007 (UTC)

Somebody would have spotted the mirror image wouldn't they using a telescope - (or maybe not) - you tell me?

(sorry)And why do I increasingly tire of answers that start "according to quantum physics"?83.100.254.236 11:20, 27 September 2007 (UTC)

Heh, see Poincaré sphere. —Tamfang 15:45, 30 September 2007 (UTC)

"quantum theories" are theories that matter/energy/whatever is quantised - you (I think) are thinking of wave theories of matter (some of which have quantisation assumptions as well) - specifically quantum mechanics.83.100.254.236 11:39, 27 September 2007 (UTC)

If the universe isn't deterministic then how did you manage to respond to this question? wouldn't you just be random dots...83.100.254.236 11:21, 27 September 2007 (UTC)

It's not entirely random. It's more like there is some randomness added to an otherwise deterministic system. You can get a general idea of what will happen in the future, but there is a limit to how accurate you can be. — Daniel 22:37, 27 September 2007 (UTC)

A system can be entirely random - yet exhibit remarkable stability. Take a bucket, fill it with 100 dice and roll them all. Add up the total. It will be remarkably close to 350 (percentage-wise that is) - almost certainly within 10% of that number. Roll a million dice and the total will be very close indeed to 3,500,000 - to within a tenth of a percent maybe. The things that are utterly random at the scale of an electron or an atom are utterly stable and predictable at the scale of a human being. The statistical nature of things means that a few atoms doing utterly crazy things simply doesn't effect large scale phenomena. There is an astronomically tiny chance of weird and wild things happening - but they are vastly less likely than rolling a million sixes on our million dice. SteveBaker 23:15, 27 September 2007 (UTC)

Who here knows General Relativity? I seem to remember reading that one of the solutions for the shape of the universe under GR has it rotating. —Tamfang 15:45, 30 September 2007 (UTC)

doubt regarding source and sink

can any one explain what are source/sink inputs/outputs? their connections in the electrical network? difference in the two networks of sourcing and sinking. ex: if the inputs or outputs of an i/o device are connected in the devicenet or controlnet network what does the input/output of that particular device mean? does it mean in teh following way.. input --input to the network output--output from th network

if not so explain me in detail. —Preceding unsigned comment added by Nag183raj (talk • contribs) 14:22, 26 September 2007 (UTC)

What kind of network? Are you talking about electronics, river systems, atmospheric chemistry? You need to clarify your question quite a lot before we can answer it! SteveBaker 14:24, 26 September 2007 (UTC)

I think we can give a general "systems" answer. The item in question (water, for example) comes from the source, and goes to the sink. In the view of that system, there are no inputs to the source or outputs from the sink. However, when considering the larger universe, there do need to be inputs to the source and outputs from the sink. If we consider a lake, for example, we can consider one river to be the source, and where it drains into the ocean to be the sink. From the POV of controlling water levels in the lake, those two are the only thing which needs to be considered. If we construct dams at the rivers that flow in and out (to the ocean), we can control the water level quite nicely, assuming the source and sink continue to function properly. However, if we view the "universe", which is the Earth's ecosystem (plus sunlight), water also evaporates from the sink (oceans) and precipitates into the source (watershed leading to upstream rivers). StuRat 14:35, 26 September 2007 (UTC)

Read the opening paragrpah of our article on flow networks. Gandalf61 15:35, 26 September 2007 (UTC)

In computer systems and business process analysis Data flow diagrams are often used to document and analyze procedures. A data source would be any process that brings data into the documented process or system ... for a example a customer filling out a purchase request is a source of data. A data sink removes data from the process. It could refer to throwing away old tax or payroll records from a filing system or deleting it from hard drive storage. Another example could be a water flow monitoring system. A flow meter taking measurements would be a source of data to the system while a non recording status monitoring panel would be a sink ... the data is displayed and then forgotten. Lazyquasar 13:55, 27 September 2007 (UTC)

Honesty in research grant applications

When people apply for grants for research, do they include their wages and the wages of all their staff? Do they ensure that the money granted goes where it's supposed to be (i.e. research proposal says 40 mice and they recieve enough money to do research with 40 mice but actually only use 30 and use the rest of the money elsewhere not stated in the research proposal). --Seans Potato Business 14:29, 26 September 2007 (UTC)

Depends on the granting agency. Sometimes the grant is meant to be specifically for exactly the costs detailed in the grant. Sometimes the grant is for overall research but they want an estimate of what that will be (but recognize that these things can change). Sometimes the granting agency gives all the money at once and never checks up on it; sometimes they reimburse based on receipts. I'm not sure there's a single answer for this. --24.147.86.187 14:45, 26 September 2007 (UTC)

It can vary depending on the source of funding and the country, but in years past I have certainly seen grant renewal documents filled out with lists of equipment that sound good and relevant to the research program, then the money was spent for otheer useful things that are more obscure. There was at that time no one for one auditing to see that 40 mice were purchased rather than 30 mice and 10 goldfish, to use your example. In one lab, rather than a 16 mm movie camera which was in the funding request, the money went for a reclining chair and a shotgun (don't ask). A string of publications in good journals trumps a lot of spending changes. Edison 15:32, 26 September 2007 (UTC)

It depends on the grant, the granting agency, the applicant, and the project. Some grants are designed to cover capital costs only: major pieces of equipment, lab construction and renovation, etc. Other grants are meant for operating costs: salary support for staff, consumables like reagents and disposable equiment, etc. Some grants will include components for both capital and operating expenses. Many research institutions will take anywhere from ten to forty percent off the top of each grant as 'overhead' before anything goes to the research group; this is to cover the cost of construction, heat, light, and shared equipment and services (deionized water, house vacuum, autoclaving and dishwashing, etc.).

There is an expectation from most granting agencies that the money granted will be spent in some way that bears at least a passing resemblance to what was specified in the grant application; how close that resemblance needs to be depends on the grant. Capital grants tend to be less flexible. If a medical researcher receives a $3 million capital grant for an MRI suite, then there will be hell to pay if he instead uses the money to build a blood chemistry lab. On the other hand, if the same researcher gets a small operating grant – say fifty or a hundred thousand dollars of seed money – to perform a basic research study and later finds that his proposed methods aren't going to work or that an early hypothesis is false, it will usually be acceptable to use the funds to perform related research using alternate methods or to prove a new (but relevant) hypothesis.

Granting agencies generally understand that research will sometimes produce unexpected results—if we always knew how a study was going to turn out, there wouldn't be any reason to do the experiments in the first place. Larger operating grants often divide money out over two or more years of work, and scientists typically have to specify (and reach) goals or milestones in order to receive continued funding. A competent researcher will have contingency plans in place (if Method A doesn't work, we will try Method B; if Hypothesis X turns out to be false, we can investigate Hypothesis Y) for when an original plan of study doesn't turn out precisely as expected. (Such plans are often presented and required as part of a grant application.)

There may also be a certain amount of forgiveness as long as a scientist is continuing to publish relevant, productive papers. A granting agency will often be pleased to see a tangential result published in a high-impact journal, even if the work done wasn't technically part of the original grant application. TenOfAllTrades(talk) 16:24, 26 September 2007 (UTC)

In my experience, funders get a little more upset when money is redirected to completely different types of spending. If your budget includes $10k to hire an undergrad, but in reality you don't hire anyone and spend the money on an instrument or travel, the funder might well feel that you are not holding up your end of the agreement. Depending on the situtation though, the funder might not know how you are spending. ike9898 18:49, 26 September 2007 (UTC)

Typhoon in Hong Kong

Where can I find out about the typhoon that badly damaged Hong Kong around Christmas-time 1936? Jasper33 14:51, 26 September 2007 (UTC)

The Typhoons of 16-17 August 1936 and 1-2 September 1937 (Appendix II to Hong Kong Meteorological Results 1937) C. W. Jeffries 1937.

Graeme Bartlett 15:16, 26 September 2007 (UTC)

Hmm, not sure either of those covers it. I have a photo taken on the west coast of Borneo on Christmas morning 1936 that has The huge seas are caused by a typhoon further north - the one that damaged Hong Kong so badly written on the back. But thanks for trying. Jasper33 15:20, 26 September 2007 (UTC)

The typhoon in August was a very severe one. It may be a not quite true label on your photo. Storm waves would not hang around for months, and the storm itself would have made a land fall and dissapated. I will look a bit further! Graeme Bartlett 15:24, 26 September 2007 (UTC)

I think the caption is correct as it is one in a series showing Christmas celebrations on the beach (including a breakfast of curry puffs). Thanks for your help Jasper33 15:29, 26 September 2007 (UTC)

The date could be right, but the beleif that the storm damaged Hong Kong may not be correct. If you have access ( look at TYPHOONS AND DEPRESSIONS OVER THE FAR EAST, AUGUST 1936 Rev.BERNARD F. OUCETTE, S. J. and TYPHOON AND DEPRESSIONS OVER THE FAR EAST, DECEMBER 1936 Rev.BERNARD F. DOUCETTE, S. J. . This last one should have your typhoon. But it only reports a depression at this time - with heavy rain. Graeme Bartlett 15:36, 26 September 2007 (UTC)

Hmm, curioser and curioser. Perhaps the caption wirter was exaggerating for dramatic effect! Thanks for going to all the trouble Jasper33 15:44, 26 September 2007 (UTC)

More on the August typhoon The reference desk would have to go to some effort to find what happens in 1936. Not many people on the desk would ahve been alive then! Graeme Bartlett 15:48, 26 September 2007 (UTC)

What a beautifully illustrated journal. They don't make 'em like that any more! Thanks again - lots of interesting details Jasper33 16:01, 26 September 2007 (UTC)

How sure are you about the year? Our List of notable tropical cyclones mentions "The Great Hong Kong Typhoon, 1937 - killed 11,000" SteveBaker 16:01, 26 September 2007 (UTC)

I know the photos have to be taken pre May 1937, as some of the people in them left Borneo at that date. Maybe what I've identified as Christmas celebrations in the photos aren't; the captions are in ink and some in blue biro and the blue biro ones are the ones which say Christmas 1936. I have a hunch that the biro captions are later additions, with the writer mis-remembering the date but not the typhoon. Who knows? Has anyone invented a time machine yet - that'd sort it! Jasper33 16:16, 26 September 2007 (UTC)

Something written with a ballpoint pen would have to have been added later - they weren't mass-produced until the early 1940's - and they weren't at all common until the 1950's. OK - so the dates could be off - making this the famous September 1937 Typhoon. So check out [1]. SteveBaker 01:44, 27 September 2007 (UTC)

Bloody hell. But not that one, as the photos have to pre-date May 1937. I'm thinking the Aug 1936 one sounds about right. Thanks for the link though - scary stuff. Jasper33 07:42, 27 September 2007 (UTC)

Number of protons in Chromium isotope

1. Isotopes of chromium include ⁵⁴Cr and ⁵²Cr

(i) Give the number of protons present in an atom ⁵⁴Cr

• Is my answer of thirty protons correct?

(ii)Deduce the number of neutrons present in an atom of ⁵²Cr

• Is my answer of twenty eight neutrons correct?

(iii) Apart from the relative atomic mass of each isotope what else would need to be known for the relative atomic mass of chromium tobe calculated. [This is the question I can't do]

Thanks guys--Hadseys 15:13, 26 September 2007 (UTC)

1. See chromium protons=24. No.

2. Yes 52-24=28

3. Correction "Apart from the relative atomic mass of each isotope.." the isotopes themselves don't have a relative atomic mass.. The other piece of info you need is the relative abundance87.102.32.155 15:20, 26 September 2007 (UTC)

Question 1: Where did you get "thirty protons?" The atomic number of Chromium is 24. If it had thirty protons, it would be Zinc.

Question 2. Chromium ⁵² would have a total of 52 protons and neutrons, and given the answer from Question 1, you can determine the number of neutrons by subtraction. Edison 15:25, 26 September 2007 (UTC)

2. A meteorite was found to contain three isotopes of element X. A mass spectromoter gave the following information about the isotopes

• Isotope 1: m/z is 24.0, its relative abundance is 64.2
• Isotope 2: m/z is 25.0, its relative abundance is 20.3
• Isotope 3: m/z is 26.0, its relative abundance is 15.5
  • Could somebody help me figure out the relative atomic mass of X please --Hadseys 15:31, 26 September 2007 (UTC)

The relative abundance is a percentage - so the percentages should add up to 100 (they do)

Simply take an average of the m/z using the percentages as weights to get an average m/z

eg average m/z_average = (24.0*64.2 + 25.0*20.3 + 26.0*15.5)/100

The value of m _average depends on z - you don't know that but usually z=1 is the major peak so assume z=187.102.32.155 15:43, 26 September 2007 (UTC)

• Therefore, is X most likely to be magnesium? —Preceding unsigned comment added by Hadseys (talk • contribs) 15:49, 26 September 2007 (UTC)

Probably87.102.32.155 16:20, 26 September 2007 (UTC)

Collared Doves - how much do they eat per day anyway?

I tossed out three very large handfuls of sunflower seed kernels for the collared doves this afternoon. Six doves landed almost immediately and began to chow down. Within ten minutes, all the seed was gone. This got me thinking - just how much can these particular birds eat in a single day? Based on past experience, they seem to be capable of eating as much food as I am willing to provide - I've seen individual birds eating non-stop at my bird table for half an hour or more. They never seem to be full. Heh, I thought that the gulls were greedy until I met these fellas... --Kurt Shaped Box 15:37, 26 September 2007 (UTC)

There are probably 2 different answers, how much they should eat and how much they will eat, given an unlimited food supply. I suspect that, like many humans, they will overeat when given free food. StuRat 17:04, 26 September 2007 (UTC)

People get full. Not all animals do. People will certainly overeat, but if you feed some animals enough, they'll eat until it kills them. — Daniel 22:35, 26 September 2007 (UTC)

Tell me about it :-((( Arghhh!!! - hydnjo talk 00:18, 27 September 2007 (UTC)

My Sun conure again

How can I tell if she's happy?

No, I don't mean if she's contented living with me as my pet, I mean how do I tell by looking at her if she's actually feeling happy at a particular moment in time?

It's easy to tell if she's angry, scared, curious, hungry, hyper, tired or even "sexually frisky" but general happiness is more difficult. Any bird owners here got any tips? --84.64.198.245 15:56, 26 September 2007 (UTC)

'Happy' is always a bit tough. How do we define happiness for humans? While there are flaws with this approach, you might want to start with Maslow's hierarchy of needs (adapted suitably for your pet) and see how far up the pyramid you get. TenOfAllTrades(talk) 16:04, 26 September 2007 (UTC)

I think my bird has most of the lower three levels of the pyramid, except the sexual stuff. She's a lone bird and I'm certainly not mating with her. :) Above that, it's hard to tell. Does a pet bird really need sexual intimacy anyway? --84.64.198.245 19:39, 26 September 2007 (UTC)

I'd just assume she's happy, unless you have some reason to think otherwise. StuRat 16:56, 26 September 2007 (UTC)

I've never owned a Sun Conure - but based on my experiences with other psittacines, standing on one foot and making clicking/grinding noises with the beak (i.e. 'chewing the cud', as I've heard some aviculturists refer to it) is a pretty good sign that the bird is chilled out and in a good mood. --Kurt Shaped Box 17:41, 26 September 2007 (UTC)

I generally agree with Kurt; when our sun conure is "chilled out", she makes small muttering noises ("Merp merp, merp, merp."). In this mood, ours doesn't stand on one foot, but instead often nestles in among her humans' clothing. Another "happy" indication seems to be a fluffy head. Also, a long burst of complicated parrot-chatter seems to mean "I'm happy to see you guys! Here's everything that's happened since the last time I saw you ten minutes ago..."

Atlant 19:29, 26 September 2007 (UTC)

When you say "chewing cud", is that used in a comparative way, or is the bird actually re-chewing previously ingested food? Nimur 18:03, 29 September 2007 (UTC)

To be honest, I'm not sure. I've watched my budgies at it and wondered this myself. The similarity in jaw movements to a cud-chewing cow is uncanny, though they could also merely be grinding the lower beak against the upper in order to smooth off any cracked edges. It's a tricky one to investigate - if you get too close to the birds while they're doing it, they stop doing it and look at you as though to say "What are you looking at?". --Kurt Shaped Box 18:19, 29 September 2007 (UTC)

Chromium

In order to obtain a mass spectrum of a gaseous sample of chromium, sample must first be ionised. Can somebody explain to me two reasons why this is necessary? —Preceding unsigned comment added by 82.36.182.217 (talk) 16:23, 26 September 2007 (UTC)

What are the units on the values you get on a mass spectrum—what do those symbols mean? Would you get actual numbers if the charge were zero? See our detailed article about how Mass spectrometry works to see what role charge plays in the operation. DMacks 16:47, 26 September 2007 (UTC)

Also the unionised gas would not be accelerated through the mass spectrometer.. really recommend reading mass spectrometry specifically with a view to looking at what must happen to the sample to register a spectrum -

Answer:the atoms/molecules need to have an electric charge, not only to be separated, but also to be detected.87.102.32.155 18:40, 26 September 2007 (UTC)

DNA testing

If semen lives for about an hour outside the body, does that also mean it could only be positively tested to identify a rapist within that hour? —Preceding unsigned comment added by 216.136.112.25 (talk) 16:44, 26 September 2007 (UTC)

Not at all, sperm doesn't need to be live to contain DNA. StuRat 16:49, 26 September 2007 (UTC)

Scientists have even discovered DNA on the order of 300,000 to 400,000 years old[2]. I regularly work with DNA from tissue that's months if not years old from the death of all its cells. — Scientizzle 18:31, 26 September 2007 (UTC)

Niels Bohr

Can you tell me what Niels Bohr's problem with his model of the atom was?

• See our article on Bohr's model --Hadseys 19:20, 26 September 2007 (UTC)

Alexander Bell

why did he invent the telephone? —Preceding unsigned comment added by 206.168.195.171 (talk) 19:52, 26 September 2007 (UTC)

All is revealed in Alexander Graham Bell. Someguy1221 20:17, 26 September 2007 (UTC)

why did he also invent a telephone? Philipp Reis had the first (although not suitable for mass market) telephone.--Stone 09:19, 27 September 2007 (UTC)

He "invented" the telephone to make a buck, although Elisha Gray in truth probably beat him to it, except for the bribing of a Patent Office employee to assist Bell's application. Reis' telephone could be adjusted to adequately reproduce speech, by means of an imperfect metallic contact, although Reis' theory did not include undulatory currents of electricity to perfectly reproduce the quality of speech. Edison 04:35, 28 September 2007 (UTC)

Oh, you're a fine one to talk, pretending to have invented the light bulb! :-) --Anon, 22:55 UTC, Sep. 29, 2007.

Facebook

On Facebook, when I scroll to the bottom of a page and press a link, then press "back" on my browser, the page goes back to the top of the page, instead of where my last spot on the page (bottom) was. Why does this happen? Is it because Facebook is written mostly in, for example, javascript? Thanks. Acceptable 21:48, 26 September 2007 (UTC)

Not quite sure what this has to with Science, but whatever.

Likely it's because you clicked a link somewhere on the page that took you to another part of the page (those little icons below the profile picture perhaps?). This happens in Wikipedia too, when you click on the table of contents to go to a certain section. These commands use anchor tags. You'll only go back to another part of the page is you clicked a link that took you to another part of a page. There's not much you can do about this. --Ybbor^Talk 22:16, 26 September 2007 (UTC)

That is called an anchor element. This question probably belongs on the Computing desk. Nimur 18:05, 29 September 2007 (UTC)

Fecal material

Can anyone tell me why the fecal material of carnivors is brown? Does it have to do with Bile? Birds and Fowel seem to have grey or green (Geese) feces. If, indeed, it does have to do with Bile, would the color be different in a person who's gallbladder has been removed? Thanks, WSC —Preceding unsigned comment added by 66.74.110.121 (talk) 23:17, 26 September 2007 (UTC)

Bilirubin is the chemical that gives it that color. I don't know about why it's different in different animals. --Sean 23:39, 26 September 2007 (UTC)

See also here (though it doesn't do much more than corroborate Sean's answer). —Steve Summit (talk) 03:04, 27 September 2007 (UTC)

Also, it's not always brown, but rather depends on what you eat. Mostly the mixture of things we eat doesn't have a very strong color, and the mix is often brown to begin with. Therefore, the effect of the bilirubin in the bile makes it even more of a pronounced brown. However, if you eat things with a single strong color, like blueberries, this can overpower the bilirubin and change the "output color". You might find the third bullet here (dealing with a lack of bile production) to be interesting: Bile#Abnormal_conditions_associated_with_bile. StuRat 12:32, 27 September 2007 (UTC)

Removal of your gallbladder doesn't stop your bile production, it just means you can't store it up for those occasional blasts of fat that we introduce into our bodies.

On another note, beets and squid ink pasta can have interesting effects on the color.

Atlant 19:05, 27 September 2007 (UTC)

As well as blue Kool-Aid. Drink a bunch of it and you'll see. Cool and safe science that kids find fascinating! Dismas|^(talk) 19:10, 27 September 2007 (UTC)

Ahh, Grossology! A great way to get kids into things scientific and yuchy!

Atlant 23:00, 27 September 2007 (UTC)

In addition to bilirubin, bile also contains biliverdin that imparts colour. David Ruben ^Talk 02:31, 28 September 2007 (UTC)

Bariatric surgery

I am trying to find any articles etc on anyone having bariatric surgery more than once.Tammyfirman 23:49, 26 September 2007 (UTC)

If you mean operations like lap-band surgery or other similar methods, they almost always "work", in that they reduce the weight of the patient over time. (They do, however, have a high rate of side effects, including death.) So, there shouldn't be a need to repeat the surgery. Doctors do sometimes need to undo the surgery, though, as some people's weight drops dangerously low or dangerously quickly. Also, surgery to remove loose skin may be needed.

If you mean surgery to actually remove excess quantities of fat, however, they may often be repeated. StuRat 12:17, 27 September 2007 (UTC)