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August 7

Scientific article self-criticism

Hello. I was wondering what the standard procedure is for including a discussion of the limitations or possible flaws of a scientific study (in chemistry in this case, though I doubt it matters) within the paper itself. DOes one generally put an independent section at the end, or what? thank you 134.48.233.92 (talk) 01:50, 7 August 2012 (UTC)[reply]

The standard structure of a scientific paper is Introduction-Methods-Results-Discussion, and that would be part of the Discussion section. Looie496 (talk) 02:28, 7 August 2012 (UTC)[reply]

It does vary.

I suggest that you go to the library of a nearby university and look at a range of scientific journals, and/or look online for scientific papers now available free, such as those put on the Web by the British Royal Society (http://rspa.royalsocietypublishing.org/). Most universities have guideline booklets - try a university bookshop. Some academic circles like the structure given above by Looie496, others prefer a structure such as Executive Summary - Conclusion - Methods & Results - Discussion - Appendicies (if appropriate).

The structure given by Louie496 is favoured by high school and college teachers, and some univesities. The structure I gave is especially favoured in industry - as it allows management, who normally don't have the time nor the expertise to understand the details (that's what they hired YOU for) to quickly decide a) your worth, and b) the commercial value of what you came up with.

If you have identified minor flaws or limitations in work you have done yourself, that do not invalidate your conclusions, you should normally include details in your discussion section. If you have identfied flaws that prevent a conclusion (sometimes an experiment you've designed fails to work due to unexpected reasons), you would include details in your discussion, and summarise it in the Executive Summary. If you are reporting on your own work, and sincerely believe you have done good work and your conclusions are valid, but you are aware that another researcher/worker/group has drawn opposing conclusions, the professional thing to do is to summarise the opposing view in an Appendix, ending with your critique of it. You don't need to copy their entire paper, you just need to reference and summarise it.

In writing any scientific paper, you should keep uppermost in your mind three fundamental things:-

1. Write for your target audience.

2. A good scientific paper does not just describe youy findings and what you did to get them. A good paper gives just sufficient (and only just sufficient) information so that (a) another competent worker can duplicate your experiment or research, and (b) allows a competent reader to spot any mistakes or omissions in your work. This can be harder to do that to describe, but it is the mark of a good paper. For example: "I tested the melting point of an xyz lead alloy by heating it until it melted. The experiment was repeated a few times and the result averaged." That's no good. "I tested the melting point of an xyz lead alloy by heating a 100g sample in a steel crucible with a gas flame. I repeated the test 6 times, allowing it to cool each time, and averaged the result" That's much better - other folk reading your paper might suspect you forgot the effect of the lead dissolving some of the iron, and they can either take into account the inaccuracy, or repeat the test with a better crucible.

3. Just because a good structure is Summary-Conclusion-Method&Results-Discussion, or whatever, it dosen't necesarily means that's what the headings must be, but the structure should be obvious.

Keit120.145.61.75 (talk) 03:29, 7 August 2012 (UTC)[reply]

I would be very surprised to see the outline(s) described by 120.145 used in a paper presenting primary research in a peer-reviewed scientific journal, which I strongly suspect is the type of situation considered by the original poster. The Abstract - Introduction - Materials & Methods - Results - Discussion - References outline is pretty much standard for academic journals (with the occasional publication that slots the Materials & Methods in after the Discussion) presenting peer-reviewed papers that are written by scientists, for other scientists—as opposed to papers written for executives, managers, politicians, or the lay public.

The limitations of a study (along with contradictory results in the published literature) are almost always addressed in the Discussion section, though there is often some connection to points brought up in the Introduction. TenOfAllTrades(talk) 04:18, 7 August 2012 (UTC)[reply]

I did say that the Summary-Conclusion-Method&Results-Discussion format is favoured in industry, and the Introduction-Methods-Results-Discussion format is more favoured in academia. Abstract is just another name for summary, though the term abstract does suggests a summary that may employ language at a specialist level, whereas the term executive summary suggests that a more lay style of language should be used. I do agree that the Abstract - Introduction - Materials & Methods - Results - Discussion - References format is very common to peer-reviewed journals. I see no evidence that the OP is in an academic environment or a commercial environment, but note that if he/she is ready to submit to a peer-reviewed journal, it is unlikely that he/she hasn't already had exposure to such journals, and should already be familiar with common formats, and indeed the "house style" of any target journal. I had considerable research & development experience, and had written many papers, while working in the research department of a large company, long before I went to university (on company sponsorship). None of those papers were published in external journals (most of them were commercially sensitive), but that does not mean they were not legitimate. They all conformed to Summary-Conclusion-Method&Results-Discussion format. A format without a single paragraph Executive Summary and a Conclusion right at the front would not have been accepted. Keit124.182.16.69 (talk) 05:33, 7 August 2012 (UTC)[reply]

I admit that I'm reading something into the OP's use of the word 'paper'. A private-sector document that was not intended for external publication is more likely to be termed a 'report', whereas 'paper' tends to be used to refer to written works that come from the academic side of the fence. (It's not a 100% hard-and-fast rule, of course.)

I'm also guessing academic (and relatively inexperienced, at that) because this question is being asked. Someone with years of experience would know the answer to the question already because of their extensive exposure to the literature; I suspect that we're dealing with a fairly young individual: perhaps an undergraduate doing a critique of a paper, or a summer student or younger grad student preparing one of his first manuscripts for publication.

Finally, of course, the OP's IP address is assigned to Marquette University—which I think is rather suggestive. TenOfAllTrades(talk) 15:57, 7 August 2012 (UTC)[reply]

Sodium triphosphate alkalinity?

How can I convert sodium triphosphate solution molarity into pH? Ideally I'd like a general formula, not just a pH of specific molarities. 70.59.11.32 (talk) 02:56, 7 August 2012 (UTC)[reply]

You'll need the 5 K_a values for triphosphoric acid. From those you can calculate [H⁺] and thus the pH.--Jasper Deng (talk) 03:08, 7 August 2012 (UTC)[reply]

"The first two pK_a values are small, pK_a3 is 2.30, pK_a4 is 6.50, and pK_a5 is 9.24."[1] I don't understand how to use these values for acidity to get alkalinity, and am hoping there is an article explaining the [H⁺] formula. 70.59.11.32 (talk) 09:14, 7 August 2012 (UTC)[reply]

In this case, then, it may be valid to assume that there is negligible disassociation after the first two protonations, so you only have to consider the last three. Depending on the amount of precision you want, though, this calculation can be arduous. See acid disassociation constant for what I'm talking about.--Jasper Deng (talk) 16:14, 7 August 2012 (UTC)[reply]

Acid dissociation constant. DMacks (talk) 17:03, 7 August 2012 (UTC)[reply]

Oh, it's coming back to me now. I repressed all this (which seems like a reasonable coping mechanism.) So for B + H₂O ⇌ HB⁺ + OH⁻, K_b is going to be K_w (which depends on temperature) divided by K_a. The temperature is going to vary unpredictably over a wide range for the underlying question, but it seems like subtracting from 14 is the accepted thing, accurate to a few percent at 25 Celsius. 70.59.11.32 (talk) 20:28, 7 August 2012 (UTC)[reply]

H2o2

What would be the fastest way to breakdown a liter of h2o2 from local pharmacy (i think concentration is 3%) to regular h2o in case of emergency? How long would it take?GeeBIGS (talk) 07:29, 7 August 2012 (UTC)[reply]

If you are trying to get drinking water, wouldn't it be easier to store drinking water ? (Store it in glass bottles, so it won't absorb chemicals from plastic.) If, for some strange reason, you find yourself with just hydrogen peroxide, how about pouring it into a blender and turning it on, to increase the reaction rate ? StuRat (talk) 07:39, 7 August 2012 (UTC)[reply]

Yes. But when all the water is gone and the filters are spent and there is no electricity for the blender for like a year and for some reason surprisingly I still have like a half bottle of peroxide left .....What would be the fastest way to breakdown a liter of h2o2 from local pharmacy (i think concentration is 3%) to regular h2o in case of emergency? How long would it take?GeeBIGS (talk) 07:46, 7 August 2012 (UTC)[reply]

Considering that people regularly gargle with 3% H₂O₂, it's apparently not all that bad in it's initial form. However, if you've lost electricity, how about pouring it into a bowl and stirring with a whisk ? StuRat (talk) 08:00, 7 August 2012 (UTC)[reply]

Even just 3% hydrogen peroxide can kill rats if swallowed, and our own article mentions some human consequences of ingesting it. I don't think it would be appropriate for anyone here to tell you how to turn H2O2 into drinking water lest you actually try it. Someguy1221 (talk) 08:07, 7 August 2012 (UTC)[reply]

Your link labeled "can kill rats" is the MSDS, which says nothing about it killing rats. StuRat (talk) 09:26, 7 August 2012 (UTC)[reply]

Are you sure? "Hydrogen Peroxide: ORAL (LD50): Acute: 2000 mg/kg [Mouse]"[2]A8875 (talk) 10:40, 7 August 2012 (UTC)[reply]

That explains it then. I did a search on "rat" and didn't find it. A mouse isn't quite the same. StuRat (talk) 22:36, 7 August 2012 (UTC)[reply]

Give me a break. All this desk talks about is crazy chemical reactions noxious explosive radioactive substances and you don't tell the op to try it. Did you just tell me to blend peroxide and drink it. Ok here goes....thanks.GeeBIGS (talk) 08:17, 7 August 2012 (UTC)[reply]

Have you read Hydrogen_peroxide#Decomposition? Throw in your silver. (Not sure how long it would take.) --Colapeninsula (talk) 09:20, 7 August 2012 (UTC)[reply]

I seem to recall that crushing a mammals liver and throwing in an extract does it pretty well, due to traces of peroxidase.--Gilderien Chat|List of good deeds 13:30, 7 August 2012 (UTC)[reply]

Potassium iodide is commonly used as a catalyst for decomposition in the Elephant toothpaste demonstration. It is also the iodizing agent in iodized salt. I don't know how well table salt would work, and in the end I suppose you would end up with salt water, which probably isn't what you're looking for... KI is also distributed for radiation emergencies to limit the uptake of radioactive iodine isotopes. If your theoretical emergency shelter has a stockpile of KI pills in case of nuclear attack, then maybe you could use one of those to catalyze it. 209.131.76.183 (talk) 15:07, 7 August 2012 (UTC)[reply]

This is not settled policy, if the poster requires more information he should feel free to ask for it. μηδείς (talk) 22:18, 7 August 2012 (UTC)[reply]

Per Medeis, there is no such policy to close this thread, and this is hardly highly dangerous anyway; hydrogen peroxide is an approved food additive. Just boil the stuff for an hour or so. That will speed up the disproportionation reaction without contaminating it with some catalyst. H₂O₂ is added to refined sugar to bleach it white and moderate ambient heat + time leads to no detectable residual reagent in the final product; just oxygen and water. 222.165.204.195 (talk) 09:25, 8 August 2012 (UTC)[reply]

If you only have a half-bottle left, boiling it for a few hours isn't going to leave you with much... Of course, I suppose I would have been out looking for water to boil long before it got to the point where I needed to drink hydrogen peroxide to survive. 209.131.76.183 (talk) 11:51, 8 August 2012 (UTC)[reply]

OK, One liter of 3% hp solution in glass bottle at room temp: how long to get all h2o? Then things to try to speed that up: boil with lid to recapture the evaporated h2o similar to salt water:, how much faster? Or put bunch of silverware in: how much faster?165.212.189.187 (talk) 15:13, 8 August 2012 (UTC)[reply]

Since this has been unhatted, let me make a clear statement: Anybody who drinks hydrogen peroxide, regardless of how it has been treated, is taking an idiotic risk. There is no plausible reason why it would ever be anything other than utterly stupid. Looie496 (talk) 16:28, 8 August 2012 (UTC)[reply]

Unless the "treatment" makes it NOT hydrogen peroxide any longer.165.212.189.187 (talk) 17:28, 8 August 2012 (UTC)[reply]

Which you would have a hard time verifying. Or, rather, let me say you would have a hard time verifying that you eliminated all but the h2o out; and for the amount of water you'd get versus getting any kind of sick from small amounts of remaining poison, I can't imagine the point- even in a wasteland emergency situation, the amount this small ration will prolong your life isn't really worth the risk, you'd be safer going out and looking for water than risking illness (unless you're talking post apocalyptic world and you have an endless supply of peroxide and lab equipment and etc., is this what we're talking?) Phoenixia1177 (talk) 09:03, 9 August 2012 (UTC)[reply]

Yes, endless supply.... whatever what is the rate of decomposition for h2o2. i know it says it in the article but I am not a scientist so I can't understand the formula. Cant someone answer this??I don't understand why everyone here is so concerned with the context of this question, or the op's ultimate motive.165.212.189.187 (talk) 13:06, 9 August 2012 (UTC)[reply]

The rate is not given in the article. The article only gives thermodynamic data from which the kinetic information that you want i.e. The rate, cannot be infered. Depending on the order of the rate equation, the actual rate may be a function of the concentration of the hydrogen peroxide, the dissolved oxygen or both or neither. As for why all the fuss about the OP's motives; this wouldn't be wikipedia without the drama. 112.215.36.172 (talk) 14:03, 9 August 2012 (UTC)[reply]

Using experimental data from a few high school science projects on hydogen peroxide catalysis I found with google and some back of the envelope calculations, 5mins of boiling should bring 30% peroxide down to less than 0.01%. Reflux that i.e. Cover the pot while boiling so you don't loose much steam and you should have fairly pure water. 112.215.36.172 (talk) 15:16, 9 August 2012 (UTC)[reply]

You seem to forget the catalysis part of those science projects.. Boiling a peroxide solution ,especially a stabilised one (and all commercial peroxide is stabilised) will not destroy the H2O2, it will boil away the water leaving a stronger concentration behind. The vapors are quite unpleasant, and concentrating H2O2 by boiling at atmospheric pressure likely ends with a runaway exothermic reaction of the liquid or a detonation of the fumes. Ssscienccce (talk) 04:07, 10 August 2012 (UTC)[reply]

The experimental controls provide uncatalysed reaction rate data. You wont boil away any significant amount of water in 5 minutes, and even less with refluxing. I buy unstabilised hydrogen peroxide for use in NAG testing all the time, but even with stabilisers, they only slow the reaction, which is over come by the heat. 112.215.36.179 (talk) 05:25, 10 August 2012 (UTC)[reply]

Oh, and the blank used in my NAG tests, is 15% hydrogen peroxide boiled for 2 hours. No explosive ignitions of vapors to date, with thousands of samples successfully tested. 112.215.36.179 (talk) 05:55, 10 August 2012 (UTC)[reply]

It's not drama, if the op was curious about the rate, they should have just asked about the rate, they specifically gave the context. If I came here and asked what is the most accurate crossbow I could build from household supplies, I'd expect an answer to that specific question; if I asked what's the most accurate crossbow I could build from basic supplies in the event burglars break into my house, I'd expect someone to comment on the stupidity of even bothering since I would be giving that analogously absurd context. Why phrase a science question in a context if that context has nothing to do with the question and no bearing on anything? I can't imagine it's just to keep things flavourful and interesting on the reference desk. Phoenixia1177 (talk) 20:45, 9 August 2012 (UTC)[reply]

Phoenix, I NEVER said that I was going to drink it. That was inferred by everyone.GeeBIGS (talk) 05:28, 11 August 2012 (UTC)[reply]

I'm not forgetting the catalysis part. You just don't seem to understand that in order to gauge the effect of a catalyst, you need a control. That control provides uncatalysed reaction rate data. You're not going to get any significant concentration of peroxide from 5 mins of boiling in any case, and ignition of vapors? Sensationalistic nonsense. The heat will cause the peroxide to breakdown several orders of magnitude faster than the water will evaporate at. The stabilisation slows the reaction, and not all commercially available product has stabilisers anyway (I need unstabilised stuff for NAG testing in my lab). 112.215.36.179 (talk) 05:25, 10 August 2012 (UTC)[reply]

Find an alkaline battery, break it open, take some of the black outer stuff (manganese dioxide), drop it in your H2O2. Ssscienccce (talk) 21:15, 9 August 2012 (UTC)[reply]

As for the time it takes, that depends on the surface area of the MnO2 and the amount of Mn ions formed. The MnO2 from batteries is a paste mixed with carbon, likely to have a big surface area. High PH is supposed to help (and is very likely since you probably get some NaOH on the MnO2 while disasembling the battery). Still it may take hours depending on amount of MnO2 and particle size. Ground potatoes or liver would do the job as well. Ssscienccce (talk) 21:56, 9 August 2012 (UTC)[reply]

Lets see... break open car battery to put in potential drinking water OR ground up some potatoes to put in? Hey 112 thanks, why don't you try some experiments and post results?165.212.189.187 (talk) 15:47, 10 August 2012 (UTC)[reply]

I'll be back in the lab on monday, so I'll have a quick go at it then. 112.215.36.179 (talk) 08:25, 11 August 2012 (UTC)[reply]

bug identification

Resolved

Can anyone identify this bug for me, please?—msh210℠ 17:44, 7 August 2012 (UTC)[reply]

It's definitely not a bug, it looks like a type of fly. What size is it? Roger (talk) 18:01, 7 August 2012 (UTC)[reply]

I was using bug colloquially. It's about an inch and a half long (ignoring the wings and feet).—msh210℠ 18:47, 7 August 2012 (UTC)[reply]

From the mouthparts and the general shape, it's either a robber fly or (less likelier) a mydas fly. That's about as far as identification can go without going to an expert and getting clearer photographs.-- OBSIDIAN†SOUL 18:12, 7 August 2012 (UTC)[reply]

It looks redder than any of our pictures of the Mydas fly, and than most of our pictures of the robber fly. Hard to tell (as you noted, Obsidian Soul) in my pictures, but this was reddish throughout: a sort of burnt sienna (or so) in some places and a sort of burgundy (or so) in others. (Except the wings, which were pale.)—msh210℠ 18:47, 7 August 2012 (UTC)[reply]

If it helps for identification, I found this bug in St. Louis County, Missouri. Thanks for the answerers' help thus far.—msh210℠ 18:47, 7 August 2012 (UTC)[reply]

It looks almost certainly to be "Hanging Thief" of some sort to me (which is in fact a type a robber fly of the genus Diogmites). Missouri would certainly be smack in the middle of their usual range. Specifically it seems likely to be a specimen of Diogmites ternatus, but the level of resolution in the photos leaves some doubt. That site is a great resource for entomological identification, btw, and you can always upload the images there for further (somewhat expert) opinions. Snow (talk) 19:24, 7 August 2012 (UTC)[reply]

Yes, that is, indeed, what it looks like. Thanks so much!—msh210℠ 19:39, 7 August 2012 (UTC)[reply]

Happy to be of help. :) Snow (talk) 19:41, 7 August 2012 (UTC)[reply]

Proof crosswords help with any objective cognitive function

I've seen a few critique articles of "brain game" (such as lumosity) garbage claims (which I'm not defending) that show evidence that doing such things only makes you good at those games with no transferable benefits, and more than one of the articles end with the same "you're better off playing a crossword puzzle." But is there objective evidence that that does anything other than make you good at crossword puzzles? 20.137.18.53 (talk) 18:42, 7 August 2012 (UTC)[reply]

You're right to be skeptical; there are a lot of non-empirical claims thrown about suggesting very precise correlations between various "brain teasers" and benefits to various cognitive functions and these are often untested (and even, to varying degrees, untestable, given the complexities of the mental functions involved). All of that being said, crosswords, being as popular and enduring as they are, have gotten a little bit more exposure to genuine structured inquiry (1, 2, 3). All of that being said, there's very little doubt that crossword puzzle does stimulate some amount of cognitive function in the area of memory recall, both in terms of maintaining the general robustness of those areas and in committing specific facts to memory (or reaffirming and strengthening those already there). But of course that's clearly obvious; making any more substantive claim than this general assumption is problematic, however. No mental task exists in a vacuum of course, and any activity which requires your focus is adapting your brain to process certain types of information, but as to which puzzle is likely to lead to a quantifiable uptake in which variety of cognitive performance (other than, as you say, repeating that exact task), I'd beware of any highly specific claims. Snow (talk) 20:17, 7 August 2012 (UTC)[reply]

This reminds me of my experience in selecting and hiring new employees (for technical roles). A current fad amongst human resource people is to have potential new empoyees do a so called aptitude test, such as Raven's Progressive Matrices (http://en.wikipedia.org/wiki/Raven%27s_Progressive_Matrices). In my experience, there is NO correlation between how well new employees turn out and their raven score. Doing well in a Raven test just proves you can do well in a Raven test. It is well known in the engineering game that occaisonally you get a new chap who has an outstanding academic record, honours, high exam marks, etc, but is fairly hopeless on the job. It seems that some folk are just good at passing exams. So yes, I think playing games alleged to improve cognitive ability probably just only improves your ability to play those games. Our local newspaper started printing a certain type of game in each Saturday issue. At first I found them very difficult and did not solve many of them. Now, after a year's practice, I solve them consistently in seconds. Does this make me a smarter perosn? I really don't think so. Wickwack124.178.171.30 (talk) 22:54, 7 August 2012 (UTC)[reply]

effect of exercise on cholesterol blood testing

Does exercising vigorously before taking a blood test for cholesterol levels affect the results of the test? — Preceding unsigned comment added by 98.207.213.14 (talk) 21:05, 7 August 2012 (UTC)[reply]

I think it could, yes. In any case, multiple tests are required, since any one test isn't that useful of an indicator. StuRat (talk) 22:33, 7 August 2012 (UTC)[reply]

It can. See [[3]]. Dominus Vobisdu (talk) 23:23, 7 August 2012 (UTC)[reply]

mars rover

How will the mars Rover get off of mars?

-wikifriend — Preceding unsigned comment added by 205.142.178.36 (talk) 21:39, 7 August 2012 (UTC)[reply]

Well how would you figure the Rover would get off of the red Planet? I just want to know what the plan is.— Preceding unsigned comment added by 205.142.178.36 (talk • contribs)

There is no plan. When the curiosity's nuclear battery finally dies, it will simply sit there forever. Perhaps one day future Mars explorers will recover it to send it to a museum on Earth, but there are no plans for that. Someguy1221 (talk) 22:11, 7 August 2012 (UTC)[reply]

Instead of bringing Mars satellites home to place in a museum, perhaps a future Mars colony will place them in a museum of their own. StuRat (talk) 06:10, 8 August 2012 (UTC)[reply]

Of course that won't stop the Earthers from stealing the rover with a number of other priceless national treasures during their violent suppression of the Cydonia Rebellion. Snow (talk) 11:09, 9 August 2012 (UTC)[reply]

Remember that forever's a long time. Assuming no further human or post-human intervention once it becomes kaput it will eventually either be eroded into dust by dust storms or buried by them in situ. The only thing we send back to Earth is the data. SkyMachine ⁽⁺⁺⁾ 22:43, 7 August 2012 (UTC)[reply]

Perhaps you are thinking of the Russion Fobos-Grunt mission launched in late 2011. That mission was to land on one of Mars's moons (Phobos or course) to collect and return a soil sample. The Mission Plan section briefly describes the return plan. Unfortunately, the Fobos-Grunt joined the ranks of many other failed Mars missions when contact was lost and it failed to leave earth orbit. -- Tom N (tcncv) talk/contrib 23:22, 7 August 2012 (UTC)[reply]

Don't read this unless you can handle a little sadness right now: http://xkcd.com/695/ --Trovatore (talk) 02:05, 8 August 2012 (UTC)[reply]

Our article on the rover depicted in the comic is Spirit rover. -- 203.82.91.147 (talk) 13:45, 9 August 2012 (UTC)[reply]

August 8

Snowflake uniqueness

Okay, so according to the snowflake article, "... it is very unlikely for any two snowflakes to appear exactly alike...". I've tried reviewing the sources, but they don't seem to clarify either; does that mean that of all the snowflakes that have ever fallen in the history of the Earth, it's very unlikely that any two were identical, or that in some undefined, arbitrary sample size, you're very unlikely to find two that are alike? If it's the latter (which I'm guessing), I think we should specify what scale we're talking about. Like, all the snowflakes that fall in a single snowstorm, or that which are in a cubic meter of snow. ❤ Yutsi ^Talk/ Contributions ( 偉特 ) 23:07, 8 August 2012 (UTC)[reply]

It means "ever," because the snowflakes shapes are caused by very specific local conditions that are constantly in flux. But it shouldn't be construed as "never", as the paragraph explains — it's just very, very unlikely. --Mr.98 (talk) 00:16, 9 August 2012 (UTC)[reply]

The first source given estimates the number of varieties of snowflakes to be in the ballpark of 10⁵⁰⁰. That number is huuuuge. The entire observable universe only has about 10⁸⁰ atoms. Someguy1221 (talk) 00:29, 9 August 2012 (UTC)[reply]

The Birthday problem seems relevant here, but I can't even guess the number of snowflakes in a cubic metre or in a snow storm.Sjö (talk) 07:38, 10 August 2012 (UTC)[reply]

You can think of it as a generalized birthday problem in a year with 10⁵⁰⁰ days, which requires somewhere around 10²⁵⁰ snowflakes before two of them are likely to be the same. Now, what follows is an illogical assumption, but it serves as an upper bound. If you assume that for every atom in the observable universe there is a snowflake, and each snowflake is reformed randomly every second, then you're still left with less than 10⁹⁸ snowflakes that have ever existed in the history in the universe. Someguy1221 (talk) 08:01, 10 August 2012 (UTC)[reply]

"Alike" is a relative term. See the most excellent website, http://www.its.caltech.edu/~atomic/snowcrystals/class/class.htm μηδείς (talk) 04:05, 9 August 2012 (UTC)[reply]

Mars Science Laboratory average speed

The news mentioned a total trip of around 567 million kilometers for NASA rover Curiosity and duration of about 36 weeks. One can conclude an average velocity of about 93750 kilometers per hour; however I couldn't find any details discussing this except that speed reduced from around 20,000km/h before entering Mars's atmosphere. Does anyone have some clue about the velocity profile and if an gravity assist was conducted during the trip?--Almuhammedi (talk) 01:23, 8 August 2012 (UTC)[reply]

Mars has a mean orbital velocity of 24.13 km/s around the Sun, so just catch up to it from behind. 88.112.47.131 (talk) 05:16, 8 August 2012 (UTC)[reply]

I don't think that 567 million km figure is very useful. That's something like 10X the distance between the Earth's orbit and that of Mars. So, what I think is happening is that the while Curiosity was moving from the orbit of Earth to that of Mars, it was also rotating about the Sun, initially at the same speed as the Earth (107,200 km/h) and later at the same speed as Mars (86,677 km/h). So, most of that travel is nothing more than the same distance an object would travel if sitting on Earth or on Mars. In this context, the relative speed of Curiosity with respect to the Earth and Mars is more significant than its speed relative to the Sun. StuRat (talk) 05:58, 8 August 2012 (UTC)[reply]

A nice animation can be found in the MSL multimedia archive here, about 3/4 into the "The Cruise to Mars" video. As the MSL trajectory converges with the Mars orbit, Mars would actually be moving faster than the MSL. The MSL flight path is actually an elliptic "Hohmann transfer" orbit that is tangent to both the Earth orbit and the Mars orbit. Earth and Mars are in the proper relative position for such a transfer roughly once every 2.13 years. -- Tom N (tcncv) talk/contrib 08:58, 8 August 2012 (UTC)[reply]

What is happening to me?

We cannot offer medical advice. Please see the medical disclaimer, and contact an appropriate medical professional. BigNate37_(T) 02:33, 8 August 2012 (UTC)[reply]

Heater and refrigerator conflict

Is positioning a fridge right beside the heater that's used to keep a room warm in winter a bad plan? I imagine the fridge might have to work harder, but I don't know whether this would be significantly inefficient, or even true. Card Zero (talk) 13:42, 8 August 2012 (UTC)[reply]

Assuming the heater is beside it, but not actually pointing at it, there should be no issue - the fridge won't work any harder than it will anyway just because the room is warmer. You can easily check though - just feel the sides of the fridge - if the side of the fridge feels a little bit warmer on the side facing the heater, than on a side facing away, then the fridge will be working a little harder - if not then it isn't. How much work the compressor does is roughly proportional to the difference between the temperature of the fridge outside walls, averaged over its surface, and the average of the temperatures inside - the freezer box temperature, meat box (if it has one) and the general food are temperature - assuming the heater is not directly heating the condenser (the black witres or black plate on the back of the fridge). Keit120.145.72.208 (talk) 14:44, 8 August 2012 (UTC)[reply]

Refrigerators work by moving and producing heat. So long as the heater does dot directly attack the refrigerator (see IP 120's response), all will be for the relative best, since refrigerators are heaters. μηδείς (talk) 04:02, 9 August 2012 (UTC)[reply]

However, the compressor is isolated from the chilled chamber for a reason. I'd say the fuller answer is that, yes, the heater is to some degree increasing the workload of the refrigerator but that the fridge is likely to be so well insulated that the increase would be negligible. 120 is actually incorrect in one point; most modern refrigerators include a thermometer and adjust the amount of time / level at which the compressor operates and so, to the extent that the ambient temperature of the room does influence the internal temperature of the fridge, then yes, it will make the compressor work harder. But again, given the level of likely insulation on the appliance and the fact that the heat in the room should be mostly evenly dissipated (assuming your average living environment) proximity between the two devices should be a virtual non-factor (assuming, as has been stated above, that the heater is not blowing directly on to the fridge). Snow (talk) 05:03, 9 August 2012 (UTC)[reply]

I could be wrong, this isn't my specialty, or anything, but I'd think that the fridge would make the heater work less (in any setup that'd normally occur, at least) Heaters stop once the room reaches a set temperature, and since the fridge also puts out heat, this would require less of the heater. As for a higher temperature in the room causing the fridge to work harder, wouldn't the room still be at the same temp if the heater were farther away since the heater is going to have to keep a decent area at the target temperature anyways. So, unless the heater is to weak to hit the target temp in the fridge area unless it is right beside it or we are talking about a heater that has no target temp, I can't see where it would have any impact at all (and maybe this is what you're talking about, still shouldn't be drastic though.) Phoenixia1177 (talk) 08:59, 9 August 2012 (UTC)[reply]

Hard to say, depends mostly on the effect it has on the airflow over the condenser coil and grill at the back of the fridge. Could increase or decrease the flow, depending on convection patterns; for example the convection of the heater (or the fan if it has one) could suck air from the other side of the fridge, providing better cooling; however, in a slightly different setting the heater could decrease the natural convection of air behind the fridge, or reverse it's direction. And as Phoenixia1177 says, if it's an electric heater, it doesn't matter. Ssscienccce (talk) 23:33, 9 August 2012 (UTC)[reply]

Why doesn't the Mars rover walk on legs?

Most animals use legs, so legs are a well tested way to get around on different types of terrain, you don't get easily stuck as with wheels. I know that legs are more difficult to implement in robotics, but in recent years a lot of progress has been made. Count Iblis (talk) 16:37, 8 August 2012 (UTC)[reply]

Still not enough progress to be as reliable as wheels - although each wheel is in fact mounted on the end of a "limited" leg of sorts. The legs have limited movement compared to for example a cockroach's legs, but that minimises the amount of operator input required to move the rover. The communication cycle starting with the rover sending "Houston we have a problem" and ending with a solution arriving back in the rover's on-board computer takes several hours - the better part of an entire day in fact. So the less the rover needs to "phone home" for fresh instructions the better. Roger (talk) 16:48, 8 August 2012 (UTC)[reply]

How long does it take for one small bit of information to traverse the distance between Mars and Earth? It is traveling at the speed of light, isn't it? Bus stop (talk) 17:02, 8 August 2012 (UTC)[reply]

A few minutes. But somebody has to diagnose the problem and figure out a feasible solution, and it has to be double checked and probably even triple checked because the slightest mistake could effectively terminate the mission. Dominus Vobisdu (talk) 17:08, 8 August 2012 (UTC)[reply]

The one way latency is evidentally 14 minutes [4]. However I wonder how little the information would be anyway. As any regular at the RD knows, someone just saying they're stuck is pretty useless information when they need help. Obviously the information flow will be optimised for what's needed to make the decision, no matter how complex the problem it's unlikely they're not going to require 100FPS 360 degrees stereo 4K 128 bit (including non visible EM spectrum) video, but it could easily be enough that it would require 30 minutes or so just to get all you need even for a simple problem (and remember one of the problems with such high latencies there needs to be a prediction of what is needed, it's not like in realtime or close to realtime communication where you can quickly ask for additional info if you decide you need it based on the other info you received). Nil Einne (talk) 18:18, 8 August 2012 (UTC)[reply]

The 14 minutes must be an average, with a delay more like 5 minutes when Mars is near Earth and more like 22 minutes when Mars is on the far side of the Sun. Presumably the rover has the intelligence to detect when it's stuck, then take pictures of the stuck wheel and send those, in which case the info could be sent quite quickly, with the main delay being the time to move the cameras into position. The rover could also be programmed with certain moves to try on it's own to get unstuck (like reversing direction or lifting the stuck wheel), but there is a risk that it could get stuck further, as a result, say be digging a rut or falling over. StuRat (talk) 18:51, 8 August 2012 (UTC)[reply]

More likely 14 minutes is the current latency. Nil Einne (talk) 21:24, 8 August 2012 (UTC)[reply]

The same question could be asked on Earth. That is, why don't we used legged vehicles here ? Of course, having nice paved roads makes wheels work better here, but we also have off-road vehicles with wheels, not legs. The ASIMO robot has legs, but I have to think that's just to make it look human. ASIMO has a walking speed of just 2.7 km per hour (1.7 mph) and a running speed of 6 km per hour (3.7 mph). So, not very fast, compared with our wheeled vehicles.

Wheeled vehicles just seem fundamentally more efficient, compared with legs, because, while the vehicle is moving at constant speed, they do, too. Legs, on the other hand, are constantly accelerating and decelerating. This type of reciprocating motion is harder on both machinery and organisms, but organisms can continuously repair the damage.

Perhaps we should then ask why organisms don't use wheels. The answer appears to be that there is no evolutionary path that leads there. An exception seems to exist for the entire organism rolling, like a tumbleweed. StuRat (talk) 18:24, 8 August 2012 (UTC)[reply]

Organisms can't use wheels because a wheel by definition must be an entirely discontiuous part separate from the rest of the object - it's attachment is purely by interlocking shapes. You can't have nerves, blood vessels, skin, ligaments, or anthing else solid crossing the boundary between wheel and not-wheel because that would prevent the wheel from turning freely and thus not be a wheel. Roger (talk) 18:44, 8 August 2012 (UTC)[reply]

I picture the wheels being like antlers, growing with a blood supply something like the velvet on antlers, then the velvet falls off and the wheel is moved into position. It could be a non-drive wheel, in which case it can just rotate around an axle (like a tusk), with a lubricant produced similar to sebum. Drive could still be from legs, with the wheels used to bear most of the weight (and all of the weight while coasting). This system would work best for an animal that lives on a flat plain, like desert scrub. StuRat (talk) 19:03, 8 August 2012 (UTC)[reply]

There's the flagellum. Apparently there is a rotating locomotion in living systems article. Nice. Sean.hoyland - talk 19:15, 8 August 2012 (UTC)[reply]

If the wheel is a non-living unit mounted on a living axle, the axle could have flexible projections or a deformable surface that nudge against cogs on the wheel. We already have evolved peristalsis to allow muscles to move "completely unattached" items, just need to turn the components inside-out or sideways. Heck, we can already move relative to other objects by crawling or monkey-bar'ing, so we just need to do that action directly on the wheel, which then transfers motion to the ground. It could be like living inside a hamster wheel of sorts. DMacks (talk) 19:22, 8 August 2012 (UTC)[reply]

Or, sticking with the model of the entire organism rolling, you could have something like an armadillo, which lives on the top of a hill, and, to escape danger, forms a ball and rolls down the hill. Unlike the above scenario, there seems to be an evolutionary path here. StuRat (talk) 19:14, 8 August 2012 (UTC)[reply]

That evolutionary path ends at the bottom of the hill where the waiting predator has learned to lie with its mouth open. 112.215.36.172 (talk) 14:32, 9 August 2012 (UTC)[reply]

StuRat, the reason why we don't have machines that use legs is because it's far more difficult to make a machine that moves using legs. The question is in line with asking why don't we have flying cars, or why don't we have batteries that have energy densities that allow laptops to run for months at a time. It's a matter of technological limitations we have. Making a machine that walks is incredibly difficult. As for whether they have any advantages over wheels, certainly. They are more agile, maneuverable, have all terrain movement, etc. They are incredibly hard to make though. A leg requires a large range of motion in different joints. Transfering energy to wheels is easy. Transfering energy to all the parts of a leg is far more challenging. The Asimo is a marvel of technology and robotics, but compare the capabilities of the Asimo to a human, and you can tell we have a long way to go still before the technology is where it needs to be. Before you think wheels are superior to legs, ask yourself if you would trade your legs for wheels. I'm sure people forced to use wheel chairs would gladly trade, and give you their parking permit as an added bonus. 148.168.40.4 (talk) 17:46, 9 August 2012 (UTC)[reply]

My idea was more for wheels to supplement legs, rather than replace them. StuRat (talk) 05:17, 10 August 2012 (UTC)[reply]

This is interesting. (Click on video.) Bus stop (talk) 19:04, 8 August 2012 (UTC)[reply]

You might be interested in the work of Rodney Brooks, who has spent his career trying to come up with very clever and unusual modes of robot locomotion. Some of them are quite successful. But at the moment I don't think any of them are as reliable as wheels. If we were shooting dozens of these things to Mars every year or so you could imagine them getting creative, but at the rate they're going you can see why they are conservative. (Brooks would probably advocate that shooting lots of little missions is a safer and more interesting idea that one big expensive mission every once in awhile, but that's something of a separate question.) Don't underestimate the difficulty of bipedal or even four-legged locomotion — it's a non-trivial technical thing to replicate, though it can somewhat be done. --Mr.98 (talk) 19:17, 8 August 2012 (UTC)[reply]

No one has mentioned the Hoop snake.. Vespine (talk) 23:23, 8 August 2012 (UTC) [reply]

Oh, please. This is not legendary. I have seen it on many holidays, weekends, and vacation days. μηδείς (talk) 03:58, 9 August 2012 (UTC)[reply]

DARPA is trying to make robots twenty times as energy efficient in movement. That's exactly how bad they suck now.

http://www.eweek.com/c/a/IT-Infrastructure/DARPA-Officials-Aiming-for-More-Efficient-Robots-301700/

Ouch! Hcobb (talk) 18:02, 9 August 2012 (UTC)[reply]

One way human tripulated mission to Mars

Are there any plans to send humans one way to Mars? It sounds shocking at the first glance, but if some people would commit suicide here on Earth, why not volunteer to flight first to Mars and die there? OsmanRF34 (talk) 16:46, 8 August 2012 (UTC)[reply]

See Mars One. They say they intend to select astronauts next year, get SpaceX and other companies to make their hardware, and fund it by making a reality TV show out of it. Yeah. 20.137.18.53 (talk) 16:55, 8 August 2012 (UTC)[reply]

As our Manned mission to Mars#The One-Way Trip Option (2006); Mars to Stay (2006) and Mars to Stay notes, the idea has had serious consideration since at least 1990. However these plans generally involved either long term pioneers or older people, people who understand and accept the risks and the likely shorted lifespan but who are truly interested in the mission rather then people who just want to die. In the short term, it is unlikely anyone would want to pay to send suicidal people or any else with significant psychological problems on even a short trip in to space let alone a long trip like to Mars. (Even if they're suicidal but aren't considered to have psychological problems, it's still unlikely to get much consideration.) Nil Einne (talk) 17:42, 8 August 2012 (UTC)[reply]

I'm 100% ready to volunteer. At least I might be useful instead of doing nothing here.--Almuhammedi (talk) 18:18, 8 August 2012 (UTC)[reply]

And I'm 100% ready to volunteer some people I know. I can leave them hog-tied by NASA's front door whenever they are ready. :-) StuRat (talk) 21:27, 8 August 2012 (UTC) [reply]

This isn't a new concept, really. During the Cold War race to the Moon, one of the ideas bandied about at NASA involved a desperate strategy to land a single man on the Moon, and keep him supplied with regular remote-controlled deliveries until they could figure out a way to bring him back: [5]. TenOfAllTrades(talk) 19:51, 8 August 2012 (UTC)[reply]

"Bandied about" in the sense that a pair of independent engineers once proposed this approach and were immediately shown the door by bemused NASA officials. Your link actually doesn't contain reference to this incident (though it is immortalized in a great scene in From the Earth to the Moon), but does note that NASA never had any attention of leaving an astronaut stranded on the moon under any circumstances. Snow (talk) 22:14, 8 August 2012 (UTC)[reply]

Somebody wasn't paying intention to their spelling... :-) StuRat (talk) 05:42, 9 August 2012 (UTC) [reply]

Hah, you should know by now that I'm capable of much more impressive typos than that! (Though I'll grant you it is an ironic one). Snow (talk) 11:13, 9 August 2012 (UTC)[reply]

Perhaps we should call that a "thinko", since you seemed to spell the wrong word correctly. StuRat (talk) 05:12, 10 August 2012 (UTC) [reply]

Analog Alarm (Wrist) Watches

Of course, digital wrist-watches with alarms are all around and familiar to every kid, but are there any analog Wrist-Watches with alarms. In that case, how do they work in such small space ? 124.253.90.126 (talk) 18:47, 8 August 2012 (UTC)[reply]

By analog, do you just mean a watch with hands? There are plenty of those these days, but they're not very interesting — they likely just have a tiny little digital alarm circuit in them and run off the same battery than runs the quartz crystal in the watch. If you mean a truly 100% mechanical watch, they do apparently exist. Here's a video of one. Pretty cool. The watch shown there obviously just has some sort of little buzzer than is powered by a manually wound spring. --Mr.98 (talk) 19:12, 8 August 2012 (UTC)[reply]

What is this insect?

I observed an ant-like insect, about one inch long, red-orange body with broad horizontal black stripes around its abdomen. It was crawling on dry mulched landscaping in a parking lot. August, 2012, Cincinnati, Ohio, USA What was it?StaGrace (talk) 19:43, 8 August 2012 (UTC)[reply]

Perhaps a termite? File:Termites shedding wings.jpg. BigNate37_(T) 19:47, 8 August 2012 (UTC)[reply]

Sounds like a cow killer. See these pics. μηδείς (talk) 20:21, 8 August 2012 (UTC)[reply]

That was my first thought as well. To the OP, note that these are wasps that are (typically) wingless and should be approached with a degree of caution. Funny, that's insect ID requests on two days running. :) Snow (talk) 22:25, 8 August 2012 (UTC)[reply]

I posted an insect ID req here for a friend almost exactly a year ago for a dragonfly species, and have been told it has returned. Seems it is the summer of the insect in NA at least. μηδείς (talk) 00:51, 9 August 2012 (UTC)[reply]

Did you ever get a positive ID on the dragonfly? Snow (talk) 04:52, 9 August 2012 (UTC)[reply]

Yes, see here: http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Science/2011_July_28#Please_identify_this_Dragonfly_species μηδείς (talk) 17:09, 9 August 2012 (UTC)[reply]

Oh, she's a pretty one! Snow (talk) 20:47, 9 August 2012 (UTC)[reply]

Yes, I have seen them all over South Jersey this month, everywhere except down the shore, where you get the verdammten greenhead fly. μηδείς (talk) 02:56, 10 August 2012 (UTC)[reply]

Whiteboard that isn't

I left some dry erase marker writing on the board too long, and it became "permanent". Windex won't remove it. Would straight ammonia be better ? Any other suggestions, or should I just toss it out ? StuRat (talk) 19:44, 8 August 2012 (UTC)[reply]

I have had great successes writing over the permanent marks using a whiteboard marker. It may just be that a chemical in the ink is doing the hard work. I've found from personal experience that the green markers tend to stain, but blue whiteboard markers erase particularly well. BigNate37_(T) 19:46, 8 August 2012 (UTC)[reply]

There's a whole bunch of suggestions on WikiHow: [[6]]. Dominus Vobisdu (talk) 19:50, 8 August 2012 (UTC)[reply]

Alcohol on a paper towel works well for this situation. Graeme Bartlett (talk) 21:24, 8 August 2012 (UTC)[reply]

Acetone works well for me. As Dominus Vobisdu's link notes, it may melt the plastic surface of some kinds of whiteboard, so test it in an unobtrusive location first. -- Finlay McWalterჷTalk 21:33, 8 August 2012 (UTC)[reply]

Shannon Lush suggests methylated spirits, or rotten milk curds. Zoonoses (talk) 01:41, 9 August 2012 (UTC)[reply]

I just did some testing myself on a "white"board that has been mostly blue for God knows how long. 95% ethanol seemed to do wonders. I assume you'd get a similar effect with rubbing alcohol. Someguy1221 (talk) 01:47, 9 August 2012 (UTC)[reply]

What about that spray that's supposed to be designed specifically for whiteboards? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:55, 9 August 2012 (UTC)[reply]

I didn't even think to look, but there is a webpage that predicted Stu's question and answered it to death: [7]. Someguy1221 (talk) 02:00, 9 August 2012 (UTC)[reply]

Specifically, they've got a winner,[8] a particular brand of fluid designed for whiteboard cleaning. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:33, 9 August 2012 (UTC)[reply]

What's the active ingredient(s) ? StuRat (talk) 05:45, 9 August 2012 (UTC)[reply]

It doesn't say. You might have to find a bottle and read the fine print. Googling it indicates it's available at Wal-Mart, which suggests it should be anywhere, although I would try an office supply store first. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:55, 9 August 2012 (UTC)[reply]

Thanks all. Some rubbing alcohol and scrubbing seemed to do the trick. StuRat (talk) 08:33, 10 August 2012 (UTC)[reply]

Resolved

E=mc²

Is E=mc² and E=mcc same thing ?

Yes, because c² means c*c. - Lindert (talk) 20:30, 8 August 2012 (UTC)[reply]

Though the latter notation has fallen out of favour. See Exponentiation#History of the notation. BigNate37_(T) 20:31, 8 August 2012 (UTC)[reply]

I have followed the link and been entirely beflummoxed. Where does it say anything about cc not being the same as c*c? (Forgive me, as having gotten a 5 in AP Calculus, and hence tested out of the bio major requirement, and so never having taken any new math after high school.) μηδείς (talk) 00:57, 9 August 2012 (UTC)[reply]

Where did anyone say it wasn't? Someguy1221 (talk) 01:04, 9 August 2012 (UTC)[reply]

Well. if this were an article I'd put a big effing "with whom" tag. So, please do tell, with whom? Do they not teach the dot as meaning multiplication anymore? μηδείς (talk) 03:54, 9 August 2012 (UTC)[reply]

I think BigNate37 meant to say that it is now unusual to write cc or c*c; people write c² instead, 'the latter' referring to E=mcc. - Lindert (talk) 08:32, 9 August 2012 (UTC)[reply]

They mean that putting "xx" in place of "x²" has fallen out of use, which is true. Though, while you could write "c * c", I don't think anyone would do this; unless, maybe, they were being explicit in some derivation that had an "a * b" in it and it later turned out a = b = c. Using an exponent is the preferred notation for powers that I have seen in countless books and papers that are from the modern era, I don't think that's really disputable.Phoenixia1177 (talk) 08:49, 9 August 2012 (UTC)[reply]

That makes more sense. μηδείς (talk) 17:06, 9 August 2012 (UTC)[reply]

A new problem formed on my car at the auto dealer. Your thoughts?

hilarious, we sympathise, but this is an explicit "request for opinions and anecdotes" with no reference desk relevance

The following discussion has been closed. Please do not modify it.

This time, it involved shorted & melted wires under the driver's dash.

My first thought: "Is this an act of service center sabotage??"

(The following was what I gathered when they called me today.)

Update on my auto woes: While the service guys at the dealership pushed my car into the service garage, when Troy turned the key to the position to unlock the steering wheel, smoke came in from under the dash on the driver's side. Troy said he removed the key for it to stop smoking.

Advisor Steve said that to fix this new issue by making some bypasses with the wires and etc., is another $340. (Some of the original parts that worked with the wires on the 2002 PT Cruiser, were no longer made, so "bypassing" was their alternative.)

This happened over a week after I elected to buy the replacement PCM from a different source for a discount (to save ~$300.)

If someone at the service center doesn't like me, I would easily envision the shorted & melted wires being an act of sabotage in order to milk me out of more $$$ than the original issue was worth. (As I said some time ago, Steve gives off a pretty unfriendly vibe. I can easily see him committing (or ordering his direct subordinates to commit) sabotage this way.)

If anyone would like to chime in their thoughts, then please do. How likely is this new problem (which occurred at the service lot, of all places) an act of sabotage? Given that my car has over 96,000 miles, and it's a 2002 PT Cruiser ("Limited" trimline), how exactly would it happen on its own?

I plan to go to the General Manager this evening after they finish working on my car, in order to voice my concerns that somebody at the service department may have sabotaged the PT Cruiser in order to get me to pay more. (Do the Service Advisors and mechanics themselves get paid by commission? If so, that would be an even bigger motivation to rip me off like this.) --70.179.170.114 (talk) 21:49, 8 August 2012 (UTC)[reply]

I've worked in the automotive service industry as a service adviser for a Honda dealership so I can speak with some authority on these issues. Service advisers are usually paid a base wage supplemented by a bonus system that works like this: Number of hours billed minus number of hours actually worked by technicians. The bigger this number the larger the bonus. However, you can't bill whatever you want. There are standardized rates for virtually any job and while there is some wiggle room, customers can make complaints to a state bureau of automotive repair if your over bill them which can land your shop in hot water. It is a motivation to do as much big ticket work as possible, but it is counter balanced by a variety of avenues for customer recourse. On top of that, service advisers need repeat customers. When I started there I didn't have any of my own customers and had to live off the dregs, mostly doing negative hour lube jobs. I had to build my customer base by gaining people's trust and eventually had people coming to me to have their transmission and engine replaced which are typically big hour jobs. If you rip off customers it is bad for you in the long run. That isn't to say there aren't shady dealings at service shops, advisers are usually not trying to save you money. but they are not also incentivized to rob their customers.

I think it is extremely unlike that they sabotaged your vehicle's wiring in the way that you described. For one thing, the payout of a few hundred dollars is way too small to be worth the risk. Dealership service departments are pulling in hundreds of thousands of dollars a week, the risk of losing their bureau registration is not worth three hundred dollars. Especially considering that what your adviser would take home more like $10 from this sabotage operation. Secondly, The PT Cruiser is known for having electrical issues, especially concerning the ignition system. While I haven't heard of this problem before, it doesn't surprise me on a car of this vintage. Finally, I think you posted before about how you've already raised a fuss with these people, talking to the general manager and so forth. The only thing we would want to do with customers like this is get them out the door and never see them again, they are almost never worth the effort. The last thing we would try to do is rip them off for a few bucks. Unless you have some kind of proof or evidence that they sabotaged your car, the general manager is likely to tell you to get lost. I once had a customer berating me over some complete nonsense. My manager over heard and told the customer that if he ever wanted to come back to our shop he'd have to apologize to me, which he eventually did.

Businesses like these require trust. If you don't trust this shop, take it somewhere else.

I feel for you but I'd question if this is a question for the science ref desk. Sounds more like a request for opinions and anecdotes. Vespine (talk) 22:30, 8 August 2012 (UTC)[reply]

It just happening to have smoke come out from under the steering wheel while you just happen to be there to witness it, at the dealership, does sound rather suspicious, to me. However, I see no point in complaining to the service manager without proof. This can only make things worse. Instead, if I have any suspicion about the honesty of a business, I take my business elsewhere. If you absolutely must make your opinion known, do so by phone or email to the manager, as auto mechanics might very well attack you physically if you are present. You could also complain to the consumer reporting agencies or regulatory agencies. (I don't see them doing much based on your complaint alone, but, if this is a pattern at that dealership, then they might.) StuRat (talk) 23:08, 8 August 2012 (UTC)[reply]

Huh? "auto mechanics might very well attack you physically"? This is a reference desk StuRat, please back up such an outrageous statement with an article link or reliable source, or strike it out. You've broken new ground on your insistence on having something to say on any and all topics. So now back it up with some sources please. Franamax (talk) 01:23, 9 August 2012 (UTC)[reply]

While it's impossible to prove what might happen, until it does, which we really want to avoid in this case, here's an example of a dealership where threats of violence (against employees, in this case) were commonplace: [9]. StuRat (talk) 01:54, 9 August 2012 (UTC)[reply]

Stu, they told me this over the phone. I was never there today, though that may have helped. While my car sat there for a week when I waited for my PCM to arrive, any one of the guys could have easily sabotaged my vehicle.

If any mechanic were to attack me, I'd let it be known to THOUSANDS. Ford headquarters would know about it, (as it's a Ford Dealer. ^{I bought the Chrysler from them "certified pre-owned."}) and so would any media outlet I could contact. The assailants would lose their jobs and see jail time. I'd win a lawsuit MASSIVE enough to pay off all my student loans (and even try to make the terms of the lawsuit include a brand-new Lincoln SUV, fully-loaded, all paid, with all registration, insurance, service/repairs and fuel free of charge, paid for by Ford themselves, for the next 10 years.)

And thanks for the suggestion about the agencies, Stu. I hope they have a bureau in Manhattan, Kansas. --70.179.170.114 (talk) 23:36, 8 August 2012 (UTC)[reply]

I said this the last time, but I'll say it again. Dealer mechanic shops are for cars that are under warranty. They mostly work on newer cars. I've never had a good experience with them except when my car was under warranty. If you know someone who's a car person, ask them if they can recommend a good shop. Also, call ahead first. If you just drop your car off somewhere and say "how much?", they might feel like you're at their mercy. You're already out the towing and the diagnostic fees, so I say cut your losses and go somewhere else. If they were going to charge you $300 more than the market value for the part, do you really think they'll give you a fair deal on the other repairs? Jerk182 (talk) 23:57, 8 August 2012 (UTC)[reply]

August 9

Curiosity landing site ?= Pambotis Lacus?

The mountain that the Curiosity rover is to look at was called Mount Sharp (Mars) until it was renamed Aeolis Mons after a convention to name features after Classical albedo features on Mars. These date all the way back to Schiaparelli (1888). But I noticed that Schiaparelli has a map from the following year with extra details (above) which seems to place Gale Crater (a quite distinctive feature in the region) at the junction of the canals Antaeus, Cerberus, Cyclops, Eunostos, and Galaxias. (See List of Martian canals for text description) Looking these up I found [10] which describes this junction as "Pambotis Lacus" (Cerulli), saying it was "admirably seen by Brown and Molesworth". - except Galaxias is replaced with Pactolus. Of course, the canals are largely illusory, but not entirely - examining the visible map of Mars, one can readily see how several canals might be perceived in most of the directions observed, at low resolution, radiating out from the crater. I wonder if the low, dark region of Gale Crater is indeed this Pambotis Lacus? Wnt (talk) 03:41, 9 August 2012 (UTC)[reply]

And more crucially, will Curiosity find signs of a hidden Thern city there? Snow (talk) 10:48, 9 August 2012 (UTC)[reply]

I don't know about the Thern (is there actually literature set in Pambotis Lacus?) but I know the area is inhabited now - good show, NASA! Wnt (talk) 13:59, 9 August 2012 (UTC)[reply]

Therns are one of a number of fictional races which inhabit Mars in Edgar Rice Buroughs' Barsoom/John Carter of Mars novels, which, like most Mars-oriented sci-fi of the day, was highly influenced Schiaperelli's theory that the "canals" were an indication that Mars had once been a lush world cultivated by an advanced race but had since turned arid. Actually, in retrospect I seem to recall the Therns lived near the planet's north pole, so I guess Pambotis Lacus might be out of the question. :) But yes, the narrative does take place largely in cities established along these defunct canals, I think. In any event, I second your sentiment -- keep up the good work, NASA. On a side note, this particular mission keeps making my mind wander to Carl Sagan and how thrilled I have to assume he'd be Curiosity's mandate -- if only he could have lived to see it. Snow (talk) 18:30, 9 August 2012 (UTC)[reply]

Rocket vaporizing launcher pad/tower

Why doesn't the exhaust from a rocket launcher, like the Space Shuttle vaporize or at least damage the launch pad and tower? I don't know what the power of the exhaust is, but I'm assuming it's a lot. But after launch they seem completely unfazed as if the exhaust is completely harmless. ScienceApe (talk) 03:51, 9 August 2012 (UTC)[reply]

Launch pad and Mobile Launcher Platform have a bit of info. I thik the short answer is that the launch sites are specifically designed to deflect the majority of the blast and withstand or absorb whatever is left. Vespine (talk) 05:55, 9 August 2012 (UTC)[reply]

Lots of water is sprayed at the base, to contain the heat and baffle the energy being produced. Also, vaporizing paint it used, which burns off, but protects the metal underneath. Sensitive equipment has protective screens and covers, which close during takeoff. 217.158.236.14 (talk) 10:20, 9 August 2012 (UTC)[reply]

I wonder how safe it is for the crowd if the burnt paint fumes waft that way. StuRat (talk) 05:05, 10 August 2012 (UTC)[reply]

Or the hydrochloric acid vapors from the SSBs? DMacks (talk) 05:26, 10 August 2012 (UTC)[reply]

is olive a citrus fruit?

Could you please tell me if Olive can be considered a citrus fruit? A science textbook meant for high school mentions it as one. I am confused as I do not seem to find concrete information either supporting or denying it on the web. — Preceding unsigned comment added by Devakalpa (talk • contribs) 07:30, 9 August 2012 (UTC)[reply]

No it definitely is not. They are not even closely related at all. Olives belong to the family Oleaceae (which includes jasmines, lilacs, ash, and forsythias) in the order Lamiales. The genus Citrus and related plants, in contrast, belong to the rue family Rutaceae (which includes white sapote, clymenia, limeberries, and jaborandi) under the order Sapindales. They're about as closely related to each other as humans are to cows. The only thing they have in common is that both plant groups are extensively cultivated for oil extracts.-- OBSIDIAN†SOUL 08:03, 9 August 2012 (UTC)[reply]

Can flavor compounds and oils dissolve in saturated syrup if they won't dissolve in water?

I'm trying to decide whether I should go for extracts or syrups when making bubble tea, iced coffees and so forth. Syrups are mostly sugar, but is using a saturated sugar solution a strategy for dissolving moderately lipophilic substances? I know oil will dissolve sugar, so can concentrated sugar solution dissolve oils, esters, aldehydes, etc? (I know that "like dissolves like" but I know that for example, the emulsifier required for oil-in-water emulsions are quite different from water-in-oil emulsions).

Sugar has a lipophilic backbone, and sweetness receptors on our tongue require both a basic, acidic and lipophilic component (the property of all sweeteners), so I'm thinking the hydroxyls in a sugar syrup will be "locked up" by hydrogen bonding leaving oils free to interact with the hydrocarbon backbone. Syrups are also really viscous and have a high boiling point so a solution could be heated up to 300F to dissolve oils; if true solvation can't occur, I'm thinking that the syrup can break up oils into a tiny suspension at high heat. Sugar doesn't crash out when a hot saturated sugar solution is brought back to room temperature, so I am thinking the oils won't crash out either.

Also when I use the frying pan at high heat I notice it's often hard to distinguish the oil phase from the aqueous phase. Nothing gold can stay (talk) 17:15, 9 August 2012 (UTC)[reply]

I am revising the heading of this section from Can flavor compounds and oils dissolve in saturated syrup if they won't dissolve in water? to Flavor compounds and oils dissolving, in harmony with WP:TPOC, point 13 (Section headings). Please see Microcontent: Headlines and Subject Lines (Alertbox).

—Wavelength (talk) 17:37, 9 August 2012 (UTC)[reply]

Please don't change perfectly okay question titles without permission. Thanks! Nothing gold can stay (talk) 23:10, 9 August 2012 (UTC)[reply]

The solution, to avoid breaking links, is to "anchor" the original alphabet soup heading, as I have now done. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:35, 10 August 2012 (UTC)[reply]

Yes, but I would like to keep my original title. What's wrong with it? Nothing gold can stay (talk) 02:22, 10 August 2012 (UTC)[reply]

There is a real problem if you put links in your title, it diosrupts the archiving process. In this case yours was just a bit long and wavelength was trying to be economic, but I think consensus is that your title was okay. Much better than titles that are to short to convey the subject matter which is a more common problem. μηδείς (talk) 02:51, 10 August 2012 (UTC)[reply]

I have now anchored the other title, again to avoid breaking links. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:14, 10 August 2012 (UTC)[reply]

How would all of Earth's electronics get shut down (as depicted on Revolution (TV series)?)

On that TV show, one day, every bit of technology that uses an electrical current gets shut down. Planes fall out of the sky, pacemakers go kaput, cruise ships get stranded in the middle of oceans, and there's just pandemonium everywhere. News can't spread fast enough; the newspapers have to run manually, like they used to in the pre-electricity days.

And I would be in an epic panic because I don't think I've known life without electronics. I would like to know what to do ifever this happens.

1. But is there ANYTHING in existence that could permanently disable all electric and electronic devices on Earth within a 24-hour period?

2. Will there be anything that may be invented soon (how soon?) that could cause this?

3. But if nothing around today can, what are the devices that can come closest to causing such a disabling event, even down to draining everyday batteries?

4. Did some early automobiles run without the aid of a battery? What were they, and how would survivors recreate such vehicles?

5. After such an event, how would survivors re-invent the battery so that we could bring electronic devices back to working order again?

6. What would this mean for cruise ship passengers in the middle of an ocean? How would they get back to land without the help of GPS, et al.?

7. I'm a(n aspiring) tech junkie, and would like to know how to live without it. Can you show me a documentary of how a prolific, hard-core tech geek survived a time-period without modern technology (perhaps by homestaying with the Amish, etc.?) ^{(There are some documentaries out there where their subjects voluntarily go through a major temporary life-change that they would not have envisioned otherwise. I hope to find one that fits the above parameters.)}

8. Most importantly, does Wikipedia have a form of print media so that we can still look upon this resource for answers in such an apocalyptic time?

8a. Also, how would we keep an editing network together without the trappings of modern life? How would we submit edits and update the resource?

Thanks, you all. --70.179.170.114 (talk) 18:09, 9 August 2012 (UTC)[reply]

A Magnetar passing by Sol System would do the trick nicely. Hcobb (talk) 18:16, 9 August 2012 (UTC)[reply]

Keep in mind the show is pure fantasy and has no relationship with likely or even possible events. Electromagnetic pulses effect electronics, but not permanently; damaged components can be replaced. As far as I can tell, the show depicts something which effects some complex non-electronic devices as well. Cars and guns don't require electronics or batteries, but appear absent in this program. Modern cars, of course, are filled with electronics, but could be replaced with mechanical components that work reasonably well: crank starting would have to replace electric starters, carburetors would have to replace electronic fuel injection. --Daniel 18:27, 9 August 2012 (UTC)[reply]

Compression ignition engines (ie. diesels) don't require electricity to run. Spark ignition engines do. --Carnildo (talk) 23:33, 9 August 2012 (UTC)[reply]

Electromagnetic pulse (EMP) events could, if strong enough, do most of what's pictured in terms of the initial shutdown. You could get that sort of thing from a massive nuclear attack or from a freakishly large solar storm. As for the permanence, though, it doesn't stack up. Nothing about EMP would prevent you from building new power plants, new computers, new whatever, even if the old ones were rendered permanently useless. That's the core idea that really pushes this into fantasy, because it's basically altering the fundamental properties of the universe. For a sci-fi take on the sort of bootstrapping that would be involved in re-creating an industrial society, consider reading the novel 1632, which posits a ca. 2000 US town transported into the 30 Years' War (the book is freely available, per the link at the bottom of the article. For #6, large ships still carry sextants and have at least one officer trained in their use, and even basic seamanship will allow you to determine approximate compass bearings to allow dead reckoning. — Lomn 18:29, 9 August 2012 (UTC)[reply]

Considering that most modern machinery is built by computer-controlled robots, if all electronics were destroyed, including those in storage and radiation-hardend military-speced ones, it would be a slowish process. We would be put back into around 1920s level tech. We would then need to build hand lathes, and hand build motors and generators. From there, we can easily get to 1940s level, with valve technology. After that, we can start building machines to build better, finer-precision machines. Since we have (hopefully!) paper/microfiche blueprints of what we want to build, we know where to go, and how to get there. CS Miller (talk) 20:38, 9 August 2012 (UTC)[reply]

Maybe the electrons started running backwards? In all seriousness, as has been already illustrated above, it's not such an unreasonable idea that all (unshielded) electronics could be decimated -- though if it occurred during an event large enough to cause the blackout all at once it would probably be happening during an ecological disaster in which our lack of GPS and toaster ovens would be the least of our concerns. But, again as has been stated, this would not lead to a permanent state of affairs since the physical principles that govern electronic devices would not be changed and damaged components could easily be replaced (and indeed, certain developed nations have been moving towards protecting their most core information infrastructure from just such an event, since an EMP is seen as a (remotely) plausible form of terrorist attack and even solar activity could theoretically cause such a mass black-out. All of that said, I'm sure that the show will come up with some form of explanation for the enduring blackout and it will, just as assuredly, be absolutely trash science. Like most science fiction that makes it to network airwaves, I'm sure the premium will not be upon the science; rather the science will be technicalities to be minimally overcome or ignored to allow a hot woman to run around being a badass with her bow in a fantasy-like post-industrial setting. That narrative might still have potential for those who can suspend disbelief with regard to the science or don't know any better, but I'm not going to hold my breath. As to your other questions, automobiles could assuredly be made to work without batteries, but the starting process would be infinitely more volatile; cruise ships, depending on the degree of integration of electronics into actual engine and rudder control, could easily navigate using pre-electronic era nautical techniques; it's impossible to speculate how you could make a "new" form of battery without knowing what silly notion exists to explain why electricity is not working properly to begin with, but bear in mind that simple batteries may go back quite a ways; the net is rife with content on how to subsist without the aid of modern technology, but I don't know of one singular overview documentary (presumably cameras are anathema to the most hardcore proponents of this movement ;); Wikipedia has no print variation as its size and constantly changing nature make this prohibitive to say the least; and yes there are somewhat similar non-digital compilations of knowledge -- back in the dark ages we called them libraries. :) Not quite as interactive, of course, but they'd do under the circumstances. Hope that helps some. Snow (talk) 19:06, 9 August 2012 (UTC)[reply]

I am revising the heading of this section from How would all of Earth's electronics get shut down (as depicted on Revolution (TV series)?) to Earth's electronics shut down, in harmony with WP:TPOC, point 13 (Section headings). Please see Microcontent: Headlines and Subject Lines (Alertbox).

—Wavelength (talk) 18:42, 9 August 2012 (UTC)[reply]

I know of no previous occurrence of this discussion here, but as a general rule we tend allow, by unspoken consensus I think, for the wording of the title to be determined by the person making the inquiry since this is not, afterall, a talk page and the question is more the product of one individual's curiosity wheras talk pages involve convergent discussions on practical procedural matters (hence the reason for the point you cite, as explicitly stated therein). That being said, if the OP has no problem with the change then I don't but I think he should feel free to return it the original form if he likes. Also, I seem to recall that changing the title after a thread has been created her causes some sort of technical snaffu (something to do with the bot archiving? Someone help me out here, what am I half-remembering?), so it may need to be changed back for that reason as well. Snow (talk) 19:15, 9 August 2012 (UTC)[reply]

Lawyers. Definitely lawyers. They lobby up for Yet Another Patent Extension, and after that the Company (there can be only one) has intellectual property rights to the idea of electric power. They install military grade crypto copy protection metering and spy devices in everything with electric power, including mandatory safety devices embedded in each bullet. One day the CEO's kid inherits the mess, but the poor drunken sop can't remember the password. Wnt (talk) 19:23, 9 August 2012 (UTC)[reply]

And Edison's ghost beaming down proudly. On the patents, that is.Snow (talk) 19:38, 9 August 2012 (UTC)[reply]

You want The Waverlies by Frederic Brown. It is available on line. μηδείς (talk) 19:46, 9 August 2012 (UTC)[reply]

If memory serves, it's The Waveries. {The poster formerly known as 87.81.230.195} 84.21.143.150 (talk) 12:28, 10 August 2012 (UTC)[reply]

[11] Count Iblis (talk) 20:51, 9 August 2012 (UTC)[reply]

What a bunch of frelling dren. I thought the BBC was above such sensationalism. No known supermassive star threatens us with the proper axial alignment to bombard us with a gamma ray burst from close enough, and no stellar remnant has been found which can be associated with any such past mass extinction. μηδείς (talk) 22:05, 9 August 2012 (UTC)[reply]

My reaction as well. And the degree of certitude they attribute to the scientific community for some of these presumed "facts" makes it all the more laughable. And are they really proposing that virtually all life on earth has been obliterated by gamma-rays regularly every 100 million years of Earth's history? Apparently all the qualified fact-checkers at BBC's science desk were on vacation at once in May of 2002? On the other hand, I love the sci-fi possibilities of this scenario; Imagine, an entire eco-system consisting of Hulked-out organisms. Hulk monkeys, hulk insects, hulk hummingbirds.... Snow (talk) 22:41, 9 August 2012 (UTC)[reply]

If something neutralized electric current everywhere, wouldn't that also wipe out any organism that had a central nervous system? ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:53, 9 August 2012 (UTC)[reply]

Yup, or just about any organism relying upon excitable cells or action potential in any context. More so than this, if you can't expect electricity to operate as it must in the physical universe as we know it, who knows how membrane potential would work and whether any organism could exist. Of course, to assume that electrical current was universally disabled across the planet (without co-occurring with the destruction of any mechanism capable of generating such a current) we'd have to assume that basic physical laws were not in play in any event and thus all means of making sense of what was occurring, or even describing it understandable terminology, would be fruitless. It's like saying, "What if temperature increases didn't lead to thermal radiation?" The fact is they do and dependencies between this phenomena and all other physical laws mean that assuming such a hypothetical is silly because you then have throw out not only the dependent phenomena but also those which give rise to the defunct principle. Very quickly the whole house of cards comes crashing down and you're just spouting gibberish (which is one of the reasons why science-fiction of the sort which inspired this thread so frequently relies on techno-babble). Snow (talk) 23:16, 9 August 2012 (UTC)[reply]

How would all of Earth's electronics get shut down (arbitrary break)

You may also want to read Greg Bear's Blood Lines (novel) which gives a pseudo-quantuum mechanical explanation of how one could change the laws of physics to end the usefulness of electronic devices. Quite a good read. μηδείς (talk) 23:34, 9 August 2012 (UTC)[reply]

@ Bugs, a sufficiently strong electromagnetic pulse would burn out most unhardened electronic circuits within its line of sight in which a current could be induced. That would not harm cells, which overall are insulators, not conductors. Excitable cellular membranes work more like serial tripping capacitors than conductors. μηδείς (talk) 23:55, 9 August 2012 (UTC)[reply]

I took the meaning of Bugs' question to be inquiring about a persistent inhibiting effect like that suggested by the sci-fi scenario in question rather than a conventional EMP. However, bearing in mind the most likely source for an EMP capable of dealing large scale damage to infrastructure, we can assume there are concordant health risks (even be they directly unrelated to the pulse itself)! Snow (talk) 00:08, 10 August 2012 (UTC)[reply]

I suppose you could accomplish a lot with nanotech - some kind of ultra smart little robots with extraordinary mobility and communication, which can invade solid machines, sense out the power, and build bridges to tap it. (fire ants are a passable prototype) You'd need a pretty asymmetric scenario (lone evil genius, or more lawyers...) to explain why a similar nanotech network can't route around the bad nano to provide power to applications. Wnt (talk) 02:24, 10 August 2012 (UTC)[reply]

Anything powerful enough to suppress charge and current, would necessarily lead to the electrostatic dissolution of atomic matter. Read The Soft Weapon by Larry Niven.

As a separate matter the OP should be aware of, non-biologists often think nerves work like little wires. They don't. Rather, a local charge differential is maintained which, if depolarized, leads to the depolarization of the next "capacitor" down the line, transmitting a signal of tripping capacitors like falling (and self-righting) dominos in one direction down the length of a neuron. There is no lengthwise flow of electrons like water in a hose as with direct current. It is more a chain of local reactions triggering the next in line, like the watchtower beacon sequence in The Return of The King. See the action potential of neurons. μηδείς (talk) 02:46, 10 August 2012 (UTC)[reply]

And there's still more to the story for nerve cells than this membrane potential manipulation via ion pumps/gates; these cells also employ myelin as insulation along the axon, causing electrical impulses to "jump" across the insulated lengths and thus propagate forward more swiftly and potently. Snow (talk) 09:11, 10 August 2012 (UTC)[reply]

If we accept the premise that electric circuits are no longer possible (and add the usual sci-fi exception for anything inside a living organism), we pretty much have to give up on computers beyond an adding machine (IBM will have to go back to its roots). However, quite a few impressive bits of technology are still possible without electric circuits:

Cars, as was mentioned, would need carburetors and crank starters. Lights would be another issue. Oil lamps or flares of some type would need to be used for headlights. Instead of blinkers, perhaps an arrow could point right, left, or up, depending on the direction you are going.

Airplanes, similarly, would need a prop start (this doesn't necessarily mean a person has to do it, they could use a machine to crank it at the airport). Instead of wires, they would need to use hydraulics to control flaps, etc. Flights at night might be problematic, as lighting would create fumes that would need to be vented. Possible, but difficult.

Rockets are theoretically possible, but would need a total redesign.

Solar power would still be possible, but would have to work by focusing sunlight on a tank of liquid, which, when heated, could then drive a motor, provide pressure for a hydraulic or pneumatic line, etc. Hydro~~electric~~, nuclear, or fossil fuel power plants could work this way, too, but a completely new power distribution system would be needed, using hydraulics, say, to deliver power to each house.

For communications, we could use fiber optics, with a mechanical shutter system blocking and unblocking a light source, similar to old movie projectors, to send bits.

For cooling, there are natural gas powered air conditioners. Heat pumps could also work off natural gas, hydraulic pressure, etc. StuRat (talk) 04:46, 10 August 2012 (UTC)[reply]

Sorry Stu, but both your communication and power grid notions are untenable. You could heat a cistern with sunlight, sure, but the amount of energy you could "focus" into it would be limited; you'd need a massive array of lenses just to get a relatively small amount of water to heat to boiling point to drive a small motor. Hydroelectric methods are by definition exclusive to the situation we are talking about here. Nuclear power cannot be feasibly maintained without a complex electrical regulation system. Fossil fuels would be your best bet for generating the energy, but here's the catch - generating it (be it by any of the above methods) is actually the "easy" the part. Delivering it via hydraulic pressure involves such massive inefficiencies and energy-loss ratios that you couldn't transport that energy very far and there would be no way to store it, so the regulation of the system for getting energy where and when it's needed would be prohibitively complex without the aid of calculating machines (and no, pressure-powered mechanical variants would not be up to the task, I'll get to that briefly). Best case scenario, a few highly intelligent people who were willing to devote the majority of their lives to maintaining and regulating their systems (and had exceptional aid and resources in this new stone age) could use fossil-fuel driven motors (and let's not forget the new difficulties arising in harvesting those in these circumstances) in order to power a few simple mechanical devices in their homes, with each such device requiring fine calibration and constant oversight to operate and tap into that mechanical energy.

The fiber optics proposal is even more dubious. First off, the maximum speed you'd be able to achieve for data transfer with a mechanical shutter system would make it about as fast as sending bits by smoke signal (probably slower, in fact, factoring in distance). That's assuming it wouldn't require tedious manual operation that would be subject to considerable error, which of course it would. Then there's the matter of how you're going to generate the consistent light of uniform intensity without electricity. Or how you're going to continue to manufacture cable without impurities (or period, given the complexities involved in the process) without the benefit of modern technology. But let's say you overcome these issues (given all of the other implausible occurrences we've been assuming from the start, we can suggest aliens are supplying you with materials and beaming down columns of pure white light and you've trained tiny microbes to translate your intended messages into binary and operate the shutters at intense speeds because, why the hell not at this point?). Where are you sending that data to? I know you already conceded this point, but it bears repeating that you don't have computers in this scenario. You could try to create mechanical equivalents (there was some experimentation along these lines prior to the advent of electrical transmission), but they would need to prohibitively gargantuan, complex, and prone to failures which would take devoted experts working around the clock to resolve just to perform anything approaching what we'd consider simple operations today. A machine with the processing power of a TI-82 would be the size of a house (and not a small one) and even then would work at a fraction of the speed, all while requiring a team of engineering geniuses to maintain, operate, and modify for different uses, if you could find and keep such people in one place for such limited gain in this new and probably quite chaotic world. And without such devices your fiber-optic system, if it were viable (which it wouldn't really be) would be at best a less reliable version of a telegram.

So, yeah sorry but the simple fact is that the digital world, for all practical intents and purposes would end with electricity. As would any practical hope of an energy grid. And those few rudimentary tools you could create and maintain would never return to you a fraction of the energy or practical use that went into developing the materials and components involved. All of your other propositions besides those two are viable, of course; and in fact they all have been employed at one time or another in formats that do not require electricity. And I grant you the rocket-powered airships would be baddass. ;) Snow (talk) 06:36, 10 August 2012 (UTC)[reply]

Mechanical shutters can be pretty darned quick. Before the electronic TV was developed in the US, the British had developed a mechanical wheel TV system. That's got to mask and unmask a lot of bits per second. I'd expect it to be used to send signals like a telegraph or text message. I don't think creating a uniform, bright light is much of a problem. Lighthouses managed to do so before electricity.

Nuclear power is still possible, but it would be more like the simple systems for space ships, not the complex systems we use in nuclear power plants today. That is, we would have many small reactors generating power for just a few homes. This model would work for other types of plants, too. There might be a power plant on every block. In the early days of electricity, before A/C, this was how it was done, using D/C.

Solar power wouldn't use lenses, it would use reflectors. There are already solar plants that use this method: [12]. You don't necessarily need to boil water, if the goal is to heat a building, you can just pipe the hot water into it. (You could also use a fluid with a lower boiling point than water, but then you'd also need to recondense it, rather than just vent the steam.) StuRat (talk) 09:18, 10 August 2012 (UTC)[reply]

It's not just a matter of how fast the shutters can open and close (though even the fastest shutters in the world are thousands to hundreds of thousands of times slower than the transfer rate of bits over even a limited network connection); a mechanical shutter is never going to approach the bitrate of even antiquated electrical systems simply because of physical limitations, but even if we ignore these physical principles and assume the shutter could move faster than in reality it could, it doesn't really matter since there would still be limiting factor of the encoding; the shutter wouldn't just be opening and closing at it's maximal rate constantly; it needs to be open and closed in specific sequences or else it's not transmitting any information. And since there is no computer handling this process in this scenario, this means that each and every bit of data needs to be sent manually (and then re-interpreted by sight on the other end). And creating the appropriate light is more complex than just having a bright source; fiber optic cables require light of a very specific intensity and spectrum which is easy enough to generate if you have an electrically generated light source attached to a digital transmitter but impossible to regulate reliably without. Lighthouses don't need any such refinement, they require only the brightest light source within the human visual spectrum reasonably available to announce their presence. Could you create something like a crude telegraph that operated over very small distances? Yeah, but it wouldn't be of much use as a communication network.

Initiating and maintaining controlled nuclear fission in a reactor would be utterly unfeasible without an electrical system, period. And it and any other plant would be subject to the limitations and efficiency issues noted in detail in my previous post, even over short distances; the amount of energy you got out of it in the form of useful mechanical work would be miniscule compared to that put into it and would require more fuel than you could possibly acquire for it. Even if we stipulate said resources, there's still the matter of regulating the flow of hydraulic pressure when and where it is needed; this could not be automated and the amount of work needed to regulate it would again dwarf any practical benefit (this is not so much an issue if you assume perhaps that hundreds of people are working for the benefit of one person to have a few amenities, but for creating an actual grid, it's unfeasible). Anyway, where's this energy going in any account? Only the smallest fraction of known human devices can operate usefully with mechanical or thermal energy alone, so if you want to warm a bath, it's fine, maybe even crank a phonograph (that's just one example of a simple device that would nonetheless have a complex integration into the system, though), but anything that absolutely required electricity previously (that is, virtually all modern human technology) is out of the question.

As for solar power, whether you use lenses or mirrors (which are not all that distinct in this context, really, as regards the function they are providing) is a non-issue. The system referenced in the link you provided still converts the energy in question into electricity, it simply uses a parabolic reflector to concentrate the light on to a receiver rather than using a photovoltaic cell. This is nothing new, similar facilities have been place for years throughout the world, but they still involve electrical current (in fact, this is a major issue for solar power, since you can't store this energy for when the sun is down, without a thermal medium, but for our purposes here this would just translate to still more energy loss). And sure, you could use the system for temperature regulation immediately on site, but that's not really the context that was being discussed. And even in that scenario you are again talking about massively more work than the benefit justifies, especially when you consider that transporting adequate water in this new post-industrial context is going to be a chore, and manufacturing the appropriate materials (parabolic lenses, for example) for every house (or even a small fraction of them) would be next to impossible and the efficiency of any such system is going to be low; these facts being why solar energy and water were never combined for much practical purpose previous to the electrical era. What it all boils down to (get it, get it? :) is that you simply aren't going to end up with grids or technology significantly more complex than what existed immediately previous to the industrial age (say, Edwardian England, for example); our advancements in understanding of material science will only carry you so far without the existence of electricity. Snow (talk) 11:33, 10 August 2012 (UTC)[reply]

I don't think you read the entire link: "As in a conventional power plant, this thermal energy can then be converted into electricity via steam- or gas-powered turbines, or it can also be used for other industrial processes such as water desalination, cooling or, in the near future, the production of hydrogen". Placing a factory near such a plant would allow you to use the energy without the distribution losses. As for power distribution, steam tunnels are still in use today in many cities, while hydraulics and pneumatics were also more widely used prior to electricity (there was even a pneumatic subway). Distributing water without electricity just requires a gravity fed system; we have many around the world now (and have had since at least Roman times). As for limited distances with a fiber optic telegraph, you could always have each operator resend the message along the next link, as was done with the early telegraph. StuRat (talk) 20:01, 10 August 2012 (UTC)[reply]

Yes, gravity fed systems have been around since Roman times -- doing the kinds of things Romans did with them, not recreating a modern power grid and technology. They are infeasible for this purpose as per discussion above. You're going to have to provide more context for which shortfalls you expect steam tunnels and pneumatics to make up for, but even before that I can safely make the blanket statement that, as with any purely mechanical system, their usefulness in recreating what would be lost with electricity is going to be very limited. As to your fiber-optic relay system, I have to ask, why would you do it this way? If you're just going to use an optical system where the major limiting factor is going to be the relay points themselves, why go to the trouble of finding and burying the wire and overcoming the (probably impossible to overcome) barriers with transmitting along it when you could just use an above-ground system of semaphore? It would be just as fast (though probably not fast enough to justify the effort over say, a letter on horseback). Well, maybe you have to keep your messages secure, because at this point if you're attempting any of this and have even the smallest fraction of the resources necessary to gain some traction, you are clearly a mad tyrant working the surviving human population to death to produce a few crude reproductions of previous technology! Snow (talk) 22:21, 10 August 2012 (UTC)[reply]

I will continue to protest that once you introduce one contradiction, you have introduced every contradiction. A circuit-shorting grey goo will either kill us all or go extinct once its foodsource is dead. That being said, StuRat's suggestions are very steampunk sexy. μηδείς (talk) 05:06, 10 August 2012 (UTC)[reply]

I doubt it. I don't know what the bastards working on smart dust have managed to accomplish, but I bet it lasts a lot longer than I want. Like any bacterium, the nanotech could "sporulate" and come out at intervals after a long period of wind dispersal. And if it's specifically designed to feed on large (>1 V) differences of electrical potential, and to use a range of reduced metals as its source of raw materials, it's hardly "grey goo". Wnt (talk) 13:09, 10 August 2012 (UTC)[reply]

Medeis is onto it like I am. I was going to ask, Sturat, do you suggest that the post-electricity cataclysm marks the beginning of the Steampunk era? If an electricity-disabling event were to ever happen in real life, please be the Steampunk's Thomas Edison, okay?

PS: How would we get phones, and mobile phones, remade through these methods? --70.179.170.114 (talk) 05:25, 10 August 2012 (UTC)[reply]

Quite simply, you wouldn't. By definition these devices work through electromagnetic mediums. This is the only telephone you'd be using. Though again, and I can't belabour this point enough, the idea of electricity not "working" (in any context that would not have already vaporized all life on the planet) makes no sense and never will. Snow (talk) 12:08, 10 August 2012 (UTC)[reply]

Land-line phones might be possible using the fiber optics system I described, and a method of translating sounds into either analog or digital optical signals. I even wonder if such systems might currently be a viable alternative to EMP-shielded electrical phones in critical locations. I think we'd be SOL on cell phones, though. StuRat (talk) 09:23, 10 August 2012 (UTC)[reply]

Ok, this is the point where I have to call nonsense. How would you translate optically-encoded patterns into acoustic waves without electricity? Snow (talk) 12:14, 10 August 2012 (UTC)[reply]

Lasers would be the new "Plastics". (Don't ask me how you would excite the crystals without electronics; line of sight would be a bitch.) But invest in lasers young man. μηδείς (talk) 05:41, 10 August 2012 (UTC)[reply]

Oh, duh. Match-lit atom bombs, x-ray lasers, mirrors and Fiber optics. μηδείς (talk) 05:43, 10 August 2012 (UTC)[reply]

Just because we can't think of something in a minute doesn't mean it isn't possible. Phenomena like superfluidity and second sound allow extremely rapid transmission of information without electricity. Light exerts pressure, stimulates chemical reactions - no reason why it can't be converted directly to sound, if someone thinks of a way. I'm going with the trained cicadas :) Any hypothetical ban on electricity, which somehow distinguishes between interfering with the conduction band of metals (and semiconductors?) and interfering with other types of excited states, leaves the possibility of using those other excited states in some ways that electricity is used now. Phonons, nuclear isomers, even some upgraded version of the tin can telephone that contains ultrasound to use as a power source (as has been proposed for refrigeration). The possibilities are endless. Our culture has not sampled every method of doing things, only the ones that were cheapest at the time. Wnt (talk) 13:23, 10 August 2012 (UTC)[reply]

Sorry, but such vague speculation doesn't cut it. We may not have created every form of technology feasible that is consistent with the physical laws of the universe as we know them, but we can make certain deductions on what is possible based on those same principles, and even further, what would be feasible under those circumstances from amongst what is possible. This is the science desk, not the science fiction desk; if he's going to make such a proposal he should be able to describe, at least in the most nebulous fashion, the mechanism that would be at work. No such mechanism exists, lacking electricity as an intermediary medium; I'll eat my hat if someone can prove otherwise. Just because a photon can catalyze a chemical reaction doesn't suddenly turn it into the Philosopher's Stone, capable of transmuting the fundamental nature of matter around it. Your joking scenario with the cicadas will come true sooner than Stu's proposed phone. The light coming over the fiber optic line would be simple binary; how is that being translated into sound waves of varying intensity and frequency at the other end via a chemical process alone? That's before considering the through-put limitations of a mechanical transmission system. So let's say you have a thousand such cables running each way (for each phones receiver and transmitter; creating/harvesting uniform cables to do this work in a post-electrical era would be next to impossible, by the way --it's not like you can just cut and splice them together to fit your needs -- but let's ignore that for now). Let's also say you've overcome the problems with creating a high intensity beam of light discussed above (almost certainly not possible without electricity, but moving on...). You've got these beams aligned and calibrated (with precision you could never achieve without modern electrical technology, mind you) to each cable. Each individual cable has its own shutter and is set up to receive the intensity data for a given frequency (there's no way the mechanical shutter would be fast enough, but let's assume you're willing to accept a significantly downgraded, almost unintelligible quality of sound). So now the moment of truth - how do you isolate all of the frequencies of a voice (or other audible sound) such that each impacts upon a different mechanism and somehow causes a chemical reaction which is somehow changed into mechanical force, but not just an force, but a force somehow starting and stopping in the exact sequence necessary to operate the shutter in a fashion to transmit the code (this is probably the most nonsensical part of the whole equation, which is saying something). At the other end, the light has to somehow catalyze a reaction or otherwise transfer into a mechanical wave which then somehow has to be re-translated into an acoustic wave (and where is the energy for that process coming from and how is it being integrated into to this temperamental system?) and each of these waves has to then somehow be recombined to reproduce the original sound. Please note that with regard to most of the "somehows" italicized above I am not just marking an unresolved detail but in fact something that is almost certainly physically impossible to achieve lacking electrical facilitation of some sort. And I've barely scratched the surface of limiting factors here. Non-electrical light phones = utter nonsense. Even if it were, can you imagine the scale of the thing and the undertaking it would constitute?. It would take lifetimes to create, massive efforts to maintain (if using chemical reactions, those chemicals would have to be created and carefully calibrated for each brief exchange), just so you can send a muddy phone message a twelfth of a kilometer every now and again? When vastly more efficient forms of distance communication would be possible? -- Optic semaphore has been suggested bellow and seems the obvious choice to me. And this is all for one pair of receiver/transmitters. How could you ever create this (already impossible) device over and over to create mass communication? Sorry guys, but the possibilities are not endless here, just apparently the speculation. :) Snow (talk) 21:46, 10 August 2012 (UTC)[reply]

Alright, here goes. You hook your microphone to a phonograph needle, which by a sensitive mechanical linkage opens a variable shutter (not digital, analog) to a powerful ultraviolet light which is always on. The light passes through the fiber optic cable to the far end, where it strikes a tape coated with photoresist. This is then etched by acid as it passes through rollers, leaving a track which goes up and down like a classic phonograph record. This is then played by a traditional gramaphone. Now true, this set-up is expensive, imposes a long time delay, and probably would have atrocious sound quality. But, I think it's fair to say it's possible. And in a society that needed to do something like this, it would be steadily upgraded, perhaps until these problems were actually dealt with rather effectively. Wnt (talk) 02:38, 11 August 2012 (UTC)[reply]

one or more fiber optics bringing through UV light

If electronics was somehow made unworkable we could still transmit power for a mile or so from a point of a prome mover, and could still communicate over distances of a mile or two by acoustic phine and transcontinentally by optic semaphore. A substantial amount of late 19th century non electric power transmission was done by pipes carrying water under pressure (hydraulic) by drivebelts on overhead poles and by compressed air. Some time ago I posted a link to an 1880's study giving details of the efficiency and cost of several of these nonelectr icpower transmission systems compared to electricity, and as I recall some were competitive over distances of less than a mile. Nathan Stubblefield patented an improved acoustic telephone system (US 378.183) in 1888 which was used commercially for distances of a mile or so. A "switchboard" would have to be devised. Pulleys were used to make turns. Speaking tubes work nicely for hundreds of feet. Bellpulls work nicely withing buildings or between nearby building for communication. Pneumatic tubes were used in the 19th century to send mail and documents for a mile or two in central business districts. Semaphore relay towers could send message over long distances day or night in the absence of fog or dust storms. Diesel engines could run without electricity, but even a gasoline powered car with a starter crank needs spark from the spark plug to run. Edison (talk) 18:44, 10 August 2012 (UTC)[reply]

According to the article Stubblefield's radio was electrical in nature. It says it wasn't a "true" radio because it used 'near field' or 'ground conduction' - but over distances of half a mile to a mile??? I still don't understand, but it wasn't acoustic. Wnt (talk) 21:10, 10 August 2012 (UTC)[reply]

I would just like to point out that in the petrochemical industry where intrinsic safety is of critical importance, there is a wide array of non-electrical systems that are suprisingly high tech. I wouldn't underestimate what technologies are possible even without electricity. 112.215.36.182 (talk) 06:18, 11 August 2012 (UTC)[reply]

Earth-Moon orbit

The Apollo missions were initially on free-return orbits to the Moon - they would do a figure-8 around the Moon and come back to Earth. Is the point that the orbit passes directly between the Earth and Moon (and crosses itself) at the L1 Lagrange point? Bubba73 ^{You talkin' to me?} 20:27, 9 August 2012 (UTC)[reply]

This sounds like a homework problem! Apollo By The Numbers, available for free online from NASA, gives precise details for all the orbital elements for each mission. Particularly, look at Earth Orbit data and Trans-Lunar Injection. If you solve the equations of motion (Buzz Aldrin wrote up a paper on exact iterative solutions to Kepler's laws, which should be "good enough"), you can forward-project the actual orbits following the TLI burn, and see if the trajectory would be anywhere near the L1 when it crosses the Earth-Moon radial line. If you accurately account for each orbital correction maneuver, you'll end up with some very non-Keplerian orbits, so I doubt if the L1 point and the radial-line crossing-point coincide - and even if they do, it probably has little analytic importance! Nimur (talk) 00:32, 10 August 2012 (UTC)[reply]

I think I can safely say that Bubba73 has long since graduated. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:31, 10 August 2012 (UTC)[reply]

Okay, put it another way: start with the L1 point. Vary the angular momentum. Calculate the lines of constant energy. If any line circumscribes both Earth and Moon, that is a Earth-Lunar free-orbit trajectory that intersects the L1 point. Nimur (talk) 01:27, 10 August 2012 (UTC)[reply]

I was thinking of an idealized orbit without rocket burns. Bubba73 ^{You talkin' to me?} 01:32, 10 August 2012 (UTC)[reply]

Yes, which is why my second suggestion was to draw out lines of constant energy, for the initial condition at the L1 point, with angular momentum as free variable. Nimur (talk) 01:48, 10 August 2012 (UTC)[reply]

I last took physics 34 years ago... Bubba73 ^{You talkin' to me?} 03:05, 10 August 2012 (UTC)[reply]

You don't need to take physics in order to understand orbital mechanics. You just need to do physics. Sometimes it helps to have a classroom setting to formalize the mathematical techniques, but that's hardly a requisite.

Conserve energy, and conserve angular momentum, and you can solve any orbital mechanics problem. There are a few coordinate substitution tricks that help deal with a rotating reference frame, but none of those are necessary to find a valid solution. My favorite method is to construct an effective potential energy field that includes the effect of angular momentum: then your object simply trades total effective potential energy for total kinetic energy, and you can easily visualize the orbital path (in the rotating reference frame). Nimur (talk) 05:50, 10 August 2012 (UTC)[reply]

I thought both of those things could be violated (unless you count the planet and moon), as in the gravitational slingshot? Wnt (talk) 15:27, 10 August 2012 (UTC)[reply]

Judging from the path shown here: http://www.braeunig.us/apollo/free-return.htm and from the value of 321.689 km (http://esamultimedia.esa.int/docs/edu/HerschelPlanck/EN_13e_L_Points_EarthMoonSystem.pdf ), I don't think it's the point where the path crosses itself. Ssscienccce (talk) 01:53, 10 August 2012 (UTC)[reply]

That is extremely interesting - I printed it out and made some measurements. It is close, but not on it. The equigravisphere is 346,089 km from the center of the Earth (0.90033 of the way to the Moon). I measured the crossover at about 350,500-353,000km from the center of the Earth. (But when the object is at the equigravisphere point, the Moon is not yet where the object loops around it, so it may be equigravipshere from where the Moon is at that point, which will through this off.) Bubba73 ^{You talkin' to me?} 03:05, 10 August 2012 (UTC)[reply]

But the equigravisphere seems to be an arbitrary definition used by NASA mission control as the point where they change reference frame, switching to distance and velocity relative to the moon instead of the earth (and confusing the journalists with the change in speed of Apollo 8). My number of 321.689 km was wrong I notice btw, it's not the distance to the center of the earth but to the center of mass from the earth + moon system. Ssscienccce (talk) 04:50, 10 August 2012 (UTC)[reply]

Note, the L1 point is not the same as the point where the gravity from the Earth and Moon are equal. L1 is in Earth orbit, so you need some gravity left to provide the centripetal force to maintain that orbit. --Tango (talk) 11:22, 10 August 2012 (UTC)[reply]

And we have seen the image of the spacecraft making a figure-8 around the Earth and Moon so often that it is easy to forget that the Moon is moving (at least for me). There is no point when the spacecraft is directly between the Earth and Moon, much less where they are pulling on it equally in opposite directions. Bubba73 ^{You talkin' to me?} 14:38, 10 August 2012 (UTC)[reply]

August 10

Metal sorting

What is the best way of extracting and sorting metals from scrap on a small scale? The process I currently use, is to take scrap, which I suspect to contain metal, pulverise it using a mortar and pestle. Followed, by roasting the grind in an oven. The oxidised grind is then solubilised in concentrated hydrochoric acid, followed by fractional electrolysis.

How do I separate the deposited metal from the gold sputter-coated glass electrode? Plasmic Physics (talk) 06:12, 10 August 2012 (UTC)[reply]

Waht do I do about the unreacted precipitate, how do I reprocess that? Plasmic Physics (talk) 06:17, 10 August 2012 (UTC)[reply]

Well, the most obvious first step is to use a powerful magnet to pull out any ferrous metals. But what exactly is the mix of "scrap" you are dealing with ? StuRat (talk) 09:49, 10 August 2012 (UTC)[reply]

Anything, including electric components, screws, bits of wire, tin cans, broken lightbulbs, bottle caps... OK, so grinding may not always be appropriate. Plasmic Physics (talk) 10:14, 10 August 2012 (UTC)[reply]

As proof of concept, I extracted some copper from an old brass coat-hook. For that, I used a graphite electrode. It was not a good idea, it disintegrated because of eletrolytic intercalation. Plasmic Physics (talk) 10:23, 10 August 2012 (UTC)[reply]

As you can tell, scrap includes non-metal components. Plasmic Physics (talk) 10:37, 10 August 2012 (UTC)[reply]

I don't understand the part about unreactive precipitate. Do you mean the metal that didn't dissolve in the HCl i.e the residue? Why are you using HCl rather than aqua regia? I think StuRat's suggestion to remove ferromagnetic things with a magnet is a good start. Based on your above list you will have iron, zinc, gold, copper, tin, lead, tungsten and more. The lead and gold wont dissolve in HCl. Nitric diluted 1:5 with water will dissolve Pb with heating, but not the gold, so that might give you some ideas for treating the HCl leach residue. Platinum electrodes are probably better, though obviously hugely expensive. If you change to a new electrode every time you change the voltage then you can remove the deposited material from the platinum with different acids i.e nitric for lead, aqua regia for gold, HCl for zinc, etc. You could also use electrodes made from the metal that you're removing. That would probably be ideal. How pure are you expecting the results to be? — Preceding unsigned comment added by 112.215.36.180 (talk) 10:59, 10 August 2012 (UTC)[reply]

A lab scale ball mill or IsaMill may also save your arm falling off from all that grinding with the mortar and pestle. 112.215.36.171 (talk) 11:22, 10 August 2012 (UTC)[reply]

Noted.

The unreactive residue would be a combination of silica, HCl-resisting metals, basically anything that reacts poorly with HCl. I'm not using aqua regia, because I don't want to strip my gold coated electrodes. I could switch to graphite electrodes when I'm reprocessing the residue, allowing me to use aqua regia. I'll make my own nitric acid the old fashioned way. Another point, what about sodium - all that electrolysing is bound to enrich the electrolyte in sodium, is there a way of negating this? Plasmic Physics (talk) 11:40, 10 August 2012 (UTC)[reply]

As far as purity goes, simply eliminating non-metal components would suffice, although I want to try and isolate the metals with purity from each other as well. Plasmic Physics (talk) 12:47, 10 August 2012 (UTC)[reply]

Some of the large scale methods may work too. For example electrostatic attraction, bubble floatation - the metal will stick to bubbles and your silica will not. Density separation, panning in a gold pan. Using aqua regia will probably result in your ingredients costing more than the metal you will recover. Graeme Bartlett (talk) 12:55, 10 August 2012 (UTC)[reply]

Sure, they may work, but equipment I don't have is needed. Which part of aqua regia is so expensive? Remember, I make nitric acid myself. Plasmic Physics (talk) 13:14, 10 August 2012 (UTC)[reply]

Panning will probably not work, since I'm working with a coilloid. Plasmic Physics (talk) 13:46, 10 August 2012 (UTC)[reply]

Perhaps some useful tips here: http://www.finishing.com/191/49.shtml Sounds like a topic that likely has been discussed on the http://www.sciencemadness.org/talk/ forum as well, maybe worth a search. Ssscienccce (talk) 14:28, 10 August 2012 (UTC)[reply]

Doyère, binomial authority for Milnesium tardigradum and so on

Hi all.
"Louis Michel François Doyère" appears to be binomial authority for Milnesium tardigradum and a bunch of other critters. (See also: Louis Michel François Doyère at Wikispecies.) Can't find enough on my own to start an article for him. Your help, please!
--Shirt58 (talk) 12:11, 10 August 2012 (UTC)[reply]

There's a scrap more (with at least one reference to hunt down) on French Wikipedia: [13] 129.234.186.45 (talk) 14:05, 10 August 2012 (UTC)[reply]

Incremental cost of second Curiosity-like rover

What would the approximate incremental cost of a second Curiosity-like rover be? I assume that the total cost of the Spirit / Opportunity pair was significantly less than twice what the cost of developing, constructing, launching, and operating a single rover would have been. -- 203.82.95.201 (talk) 13:29, 10 August 2012 (UTC)[reply]

$5 Billion, because you first need to build the Chemistry and Metallurgy Research Replacement Facility to make the plutonium. Hcobb (talk) 14:38, 10 August 2012 (UTC)[reply]

Strictly speaking, you don't need that facility (which doesn't exist yet, mind you), you just need some way of getting the plutonium-238. There are lots of ways to do that for far cheaper than $5 billion. The Multi-Mission Radioisotope Thermoelectric Generator used in Curiosity was not produced there (from what I gather, it was produced by Idaho National Laboratory), and there's no reason to assume the next one would need to be, either. The off-the-shelf cost for the MMRTG is quoted as $100 million, so it's not very cheap. I don't know what the full system costs are, but they would be somewhat misleading, given that it is not a single-use facility. I wonder if the OP isn't asking about the marginal cost, though — what making the next rover would cost without all of that spending on R&D. --Mr.98 (talk) 17:13, 10 August 2012 (UTC)[reply]

Yes, I suppose I did intend to ask about marginal cost. I see that Incremental cost redirects to Marginal cost where it says:

For discrete calculation without calculus, marginal cost equals the change in total (or variable) cost that comes with each additional unit produced. In contrast, incremental cost is the composition of total cost from the surrogate of contributions, where any increment is determined by the contribution of the cost factors, not necessarily by single units.

Frankly, that definition leaves me clueless as to what incremental cost is. I understand what follows:

For instance, suppose the total cost of making 1 shoe is $30 and the total cost of making 2 shoes is $40. The marginal cost of producing the second shoe is $40 - $30 = $10.

What about a simple example for incremental cost? -- 203.82.95.201 (talk) 19:37, 10 August 2012 (UTC)[reply]

The one rover concept for ExoMars which was based on a MSL Landingsystem and a MSL type rover with a mixed ESA NASA Payload had a prise tag from JPL of 1 billion. The MAX-C rover was nor built because it was not possible to build it for less than 2.5 billion. So for me this looks like JPL would like to have 1 or better nearly 2 billion for a rebuilt MSL rover. The plutonium for one more mission and the the new sterlig driven RTG are already availabel. The one thing I hear about JPL is that they never fly a successfull mission twice.--Stone (talk) 18:11, 10 August 2012 (UTC)[reply]

Yea, and that never seemed wise to me. The Spirit/Opportunity were so successful, they should have just sent a dozen more of those (perhaps upgrading the scientific instruments, but not changing the rest). But, since they've now gone and spent billions on the next generation, I would hope, if it's successful, they will send multiples of those, instead of again starting from scratch. Their failure to reuse successful designs is a big part of the reason why NASA launches are becoming prohibitively expensive, and they must now look to private enterprise to do things in a more reasonable way, since they refuse to do so. StuRat (talk) 19:32, 10 August 2012 (UTC)[reply]

JPL is not only building like the good old Ford model T, but they have people developing things and those people have to have a job because you need them later. The only way to make the thing work is provide JPL with a new development project every few years to ensure money for 2000 people. This is not a science question and never will be but a business question. This is true for ESA too. --Stone (talk) 21:11, 10 August 2012 (UTC)[reply]

In that case, put them to work on something which really does need a new design from the ground up, like a manned mission to Mars. We need a faster propulsion system, better shielding, fewer g's, a much larger payload, etc., all of which requires a complete redesign. Or, if that's too ambitious, start with the new manned mission to the Moon. (Since we haven't gone to the Moon for 4 decades, a new design there is OK.) StuRat (talk) 02:44, 11 August 2012 (UTC)[reply]

Estimating cost for spaceflight is so complicated that NASA Johnson Space Center has an entire division dedicated to the task. NASA's Office of Cost Estimation has an entire website full of references, and a complete textbook, Cost Estimating Handbook. If you care to see real numbers, NASA's FY2013 budget is available online. There are also proposed budgets for future years, including projections for future Mars expenditures. The Planetary Science projections contain entire chapters discussing tradeoffs and budget considerations for Mars missions. Notably, "a $226.2 million decrease from the FY2012 estimate," ... as Mars Science Laboratory "entered Operations phase and requires much less funding indicative of significant reductions in the workforce." This means that building a second rover is not in the budget. The project budget breakdown does indicate specific line-item costs that correspond directly to "building" a rover; but you can't just buy a rover - even if you magically found the money for it. You have to appreciate that this reported "rover cost" is part of an entire program, corresponding to a schedule, a strategy, and an operational budget. And, the entire Mars program has suffered a projected 37% budget cut - so, there's no money to buy a new rover, and no money to launch it, and no money to hire a workforce to design, manage, or operate it. Even if you got a rover for free, you couldn't put it on Mars in this funding environment. Nimur (talk) 20:59, 10 August 2012 (UTC)[reply]

NASA got two Hubble Telescopes for free and they pay to store them. They do not have the money to make them part of a mission and pay for launch and ground support. --Stone (talk) 21:11, 10 August 2012 (UTC)[reply]

Back in the old days it was pretty common for the US to do two interplanetary probes about the same time, e.g. Mariner 1 &2, 3&4, 6&7, 8&9, Viking 1&2, Voyager 1&2, Pioneer 10&11. The main reason for failure in those days was the rocket. Bubba73 ^{You talkin' to me?} 02:17, 11 August 2012 (UTC)[reply]

For the interesting history, see For the interesting history, see Mariner program, Pioneer program, Viking program, and Voyager program. Bubba73 ^{You talkin' to me?} 04:01, 11 August 2012 (UTC)[reply]

@Stone, are you saying their are twom more Hubbles that simply haven't been launched? (!!!) Please provide a link. μηδείς (talk) 04:10, 11 August 2012 (UTC)[reply]

They were given two mirrors (mirrors only) by the US military. Bubba73 ^{You talkin' to me?} 04:21, 11 August 2012 (UTC)[reply]

(UK) approx. inch and a half long insect with a long thin sting, wasp colours but not a wasp shape

I've literally just come into the house out of the way of a bizarre insect the likes of which I've never seen before. At first I thought it must be a hornet, but it does not resemble a wasp aside from its black and yellow bands (large bands, only a few on its entire body), it's definitely not a European hornet which to look at is just a larger wasp.

This thing's wings were large and folded over its back like a beetle, but it was longer and thinner more like a wasp/honey bee, it was shiny rather than furry. Its antannae (sp?) were bright yellow, as were it's legs, these appendages looked like luminous fishing wire, quite thick and bright yellow. Its sting was long and thin and was at least a couple of centimetres if not longer, compared to a wasp it was much longer in comparison to its body. The body itself did not (from a respectful distance) look visibly segmented, it was a slightly angular sausage. Its shape was quite similar to the naiads image in the mayfly article. When it flew it was steady but quite slow, sort of menacing like you get in those killer insect films.

Anyway, I'm surprised to put it mildly after popping into the back garden and finding this thing sunning itself on the patio table, when it started lazily flying around me I had the sudden urge to run away squealing :S Can someone suggest what this thing might be? Someone another 15:18, 10 August 2012 (UTC)[reply]

Most likely a hoverfly, I think -- some of them have wasp-mimic coloration. However I always have trouble understanding verbal descriptions of insects, and there are many species that mimic wasps. Looie496 (talk) 16:13, 10 August 2012 (UTC)[reply]

We do have plenty of hoverflies, but the only species I know of around here are the little thin ones which are much smaller than any bee and don't resemble them physically. This thing had droopy antennae which reminded me of those giant african millipedes, the way the legs and antannae were also a different colour to the rest of it also reminded me of those. This thing was huge, the only native insects I've seen of that size have been (what I assume to be) European hornets and the larger species of grasshoppers. The way the thing was put together spoke more of scorpions and cockroaches than beetles, bees and flies. It is very difficult to describe it but it was weird. It may only be pretendy-poisonous and be wearing those colours to mimic as you point out the hoverflies do, but that prong sticking out of the back of it was thick and very nasty looking. Someone another 16:58, 10 August 2012 (UTC)[reply]

Ichneumen wasp, probably. The "sting" is an ovipositor. --TammyMoet (talk) 16:52, 10 August 2012 (UTC)[reply]

Ah, I'm not familiar with these, but looking at the image there it shares the same droopy antennae and nasty stingy thing. The body shape was more linear but the image in that article shares the same sort of.. well, loathsome appearance. It was pretty in its own way but while dressing up as a wasp and having that ovipositor protruding from the back it looked like the kind of thing you'd never want to be locked in a room with. I'll keep my eye out in case it comes back for a photo. Thanks to you both. Someone another 17:01, 10 August 2012 (UTC)[reply]

Here's one that's dressed up like a wasp: http://en.wikipedia.org/wiki/File:IC_Ichneumon.JPG 109.99.71.97 (talk) 17:50, 10 August 2012 (UTC)[reply]

The colours were certainly proper wasp colours like that, but it looked quite different. It seems very likely that it was one of these wasps, I just wish I got a photo of it :( Need to sort out a camera for these weird encounters. Someone another 21:45, 10 August 2012 (UTC)[reply]

Have you browsed a google image search for "ichneumonon" [14]? (Ichneumonid [15] has different hits) Also- those long ovipositors are no risk to you. They are solely for boring into wood, which can take hours! SemanticMantis (talk) 22:56, 10 August 2012 (UTC)[reply]

User:Someone another might be made of something softer than wood, and perhaps therefore doesn't want to risk it! I saw "ovipositor", and, classical education and all that, thought it just wanted to lay some eggs for breakfast, not bore into people! :) --Demiurge1000 (talk) 03:35, 11 August 2012 (UTC)[reply]

Ichneumon wasps are not loathsome. They're the ninjas among wasps! :( They're one of the most skillful users of chemical warfare in the insect world, with most species famous for the polydnavirus that have actually symbiotically merged into their DNA, becoming biological weapons. Every cell in the wasp has a copy of the virus from birth and every time they lay eggs they also deliver the virus which infect the host and suppresses its immune system, leaving the baby wasps free to eat the unfortunate host alive. Like other parasitoid wasps, they're also famous for their "mind control" methods. For example, Ichneumon eumerus (which I should make an article on) starts ant civil wars, so they can enter the anthills unharmed and lay their eggs on the lycaenid butterfly larvae inside (who incidentally also use their own chemical allures to trick ants into thinking they're baby ants and thus feed and protect them).

And like most parasitoid wasps, the majority of ichneumon wasps do not sting. Particularly those with very long ovipositors. As mentioned, wasps which have them use those for boring through plant material (see sequence of pictures in the Ichneumonidae article), substrate, or directly through the body of their hosts (see pictures in our Braconidae article). The long ovipositors in the latter are because some caterpillars are covered with defensive hairs (which probably evolved as a defense against the wasps in the first place). However, members of the subfamily Ophioninae among ichneumonids have shorter ovipositors, and those do sting. But only in self-defense. Also it's not dressing up as a wasp. It is a wasp.-- OBSIDIAN†SOUL 05:13, 11 August 2012 (UTC)[reply]

Year we would live on mars.

Who and when would we arive on mars? Would we be able to move there and live? What year is this possible? — Preceding unsigned comment added by 205.142.178.36 (talk) 15:46, 10 August 2012 (UTC)[reply]

Please read Manned mission to Mars. Looie496 (talk) 16:02, 10 August 2012 (UTC)[reply]

thank you so much that was a great read. — Preceding unsigned comment added by 205.142.178.36 (talk) 17:08, 10 August 2012 (UTC)[reply]

It's going to depend greatly on what you mean by "living there". If you mean send a person to live there for a few weeks during a mission, we might be able to do that in a decade or so, if we decide to do so. If you mean establishing a permanent Mars base, with supplies ferried from Earth on a regular basis, that would be more like a couple decades, if we wanted to fund that. If you mean establishing a self-sustaining Mars base, that would take several decades. If you want to terraform Mars so people can live outside, without space suits, then we're talking about centuries. StuRat (talk) 19:22, 10 August 2012 (UTC)[reply]

"Centuries" is extremely optimistic. If every country in the world devoted its entire industrial capacity to terraforming Mars, the project would still take thousands of years. Keep in mind that 150 years of the entire world's CO2 emissions have not even managed to raise Earth's temperature by a degree, and have only raised the CO2 concentration from 280 to 395 ppm, less than 1/10000 of the entire atmosphere. --140.180.5.169 (talk) 06:50, 11 August 2012 (UTC)[reply]

Living longer with a transplanted heart

Could you live longer than expected with a transplanted heart? It's true that auto-immune medicines pose a disadvantage, but on the other hand maybe you are a sedentary 65 and get a heart of a young and healthy motorcycle rider. OsmanRF34 (talk) 18:29, 9 August 2012 (UTC)[reply]

~~Wrong desk -- but I'll leave it to you to move the question. Looie496 (talk) 18:32, 9 August 2012 (UTC)~~[reply]

~~I think he is coming from a technical stand point not a natural medical stand point.~~

There is a huge amount of risk involved in a heart transplant, so, if you are asking about a hypothetical sedentary 65 year old with no sign of heart disease getting a heart transplant "just in case", that would lower their life expectancy. However, at some point on the future, when we can do the surgery with far less risk, and can grow spare, compatible hearts in a lab, then it might actually make sense to do such a preventative surgery. StuRat (talk) 04:01, 10 August 2012 (UTC)[reply]

I'm asking in a real-life scenario. I know that hearts for transplants are scarce and transplantations risky. OsmanRF34 (talk) 16:59, 10 August 2012 (UTC)[reply]

Um, the whole point of a heart transplant is that the recipient is likelier to live longer with one than without. Are you suggesting it as elective surgery? μηδείς (talk) 18:55, 10 August 2012 (UTC)[reply]

I think he's asking about heart transplants for older people with no signs of heart disease. People do sometimes die of undiagnosed heart problems, so the idea isn't completely absurd. However, at present, the risk of the surgery and rarity of donor hearts would make this unwise. StuRat (talk) 19:16, 10 August 2012 (UTC)[reply]

Reformulating the question: given a 65 years old (and given a general life expectancy of 15 years for 65 year old people), who gets a heart of young healthy motorcycle rider. On the one hand, heart transplants may decrease your chances of hitting that general life expectancy, but you are also getting a healthy and young heart, which improves your life expectancy. Considering his advantages and disadvantages, can he maybe surpass that general life expectancy? OsmanRF34 (talk) 21:27, 10 August 2012 (UTC)[reply]

The question is hugely speculative. I don't think you can say we're anywhere near the point where heart transplants will be elective, like, say, stomach stapling, which I have seen go very bad for two acquaintances, one who has lifethreatening nutrition problems, and the other who became addicted to pain killers leading to a very tragic divorce. The article talks about survivors. μηδείς (talk) 21:52, 10 August 2012 (UTC)[reply]

The question is not hugely speculative. It's about comparing the life expectation of an average 65 years old to the life expectation of a 65 years old with the heart of a 20 years old. Who is going to live for a longer time? The latter has advantages and disadvantages, which are more important? OsmanRF34 (talk) 23:56, 10 August 2012 (UTC)[reply]

The unaltered 65 year old is, on average, going to live for a longer time. --Demiurge1000 (talk) 03:30, 11 August 2012 (UTC)[reply]

Time manipulation

If i could manipulate time in a mannor of freezing atoms could i move the atoms using my own force(i am not frozen)? — Preceding unsigned comment added by 205.142.178.36 (talk) 17:07, 10 August 2012 (UTC)[reply]

The real laws of physics don't allow "manipulation of time" of the sort you describe. You would have to invent fictitious laws of physics that would allow such a thing, then figure out what the fictitious laws say about your question. -- BenRG (talk) 17:41, 10 August 2012 (UTC)[reply]

Haven't physicists been able to hold atoms stationary, by lowering the temperature and then using a laser or some such to stabilize the position? Haven't they been able to move individual atoms around? Edison (talk) 18:20, 10 August 2012 (UTC)[reply]

Laser tweezers are used to lower kinetic energy of individual atoms - which reduces their net motion. It does not "freeze time;" it merely reduces the test-particle's energy (and hence, the amount and velocity of movement). Nimur (talk) 18:56, 10 August 2012 (UTC)[reply]

Stopping time is easy. Just jump into a Black hole. Hcobb (talk) 18:25, 10 August 2012 (UTC)[reply]

I am asking this cause im righting a comic book about a man who has the ability to manipulate time and i want it to work out in a scientific way. — Preceding unsigned comment added by 205.142.178.36 (talk) 20:25, 10 August 2012 (UTC)[reply]

Since time manipulation is impossible in the way you describe, you'll have to resort to what everyone else does: Either gloss over it completely, or throw scientific sounding words out there so people think you know what you're talking about. Someguy1221 (talk) 20:54, 10 August 2012 (UTC)[reply]

In particular, "stasis field" is a fairly standard scientific-sounding phrase that's used in fiction to describe such things. But if you want to use something new, it's fairly easy to create scientific-sounding nonsense, such as "localized temporal inflection point". Red Act (talk) 21:48, 10 August 2012 (UTC)[reply]

You can't make it scientific, so throw that goal out. The best you can do is make it self-consistent. For that, you'll have to come up with a model for how the time is frozen. Make the model as convenient to the plot as you need it to be. --Mr.98 (talk) 20:54, 10 August 2012 (UTC)[reply]

This is a much-explored sci-fi area. One trivial example was My Favorite Martian, where the Martian could point at someone and make them "freeze". That wasn't a stoppage of time, it was merely suspended animation. Seems to me The Twilight Zone had a story about that kind of thing. One variation on this idea sounded more plausible, the Star Trek episode about a group of people who somehow operate at an accelerated rate, so the Enterprise crew is not literally frozen, but they move very slowl (in relation to the accelerated group). ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:51, 10 August 2012 (UTC)[reply]

Only acceptable answer to a world with imaginable rules: they can be what you imagine them to be. Most SF don't care about it being tangentially possible, and that doesn't make them less attractive as fiction. OsmanRF34 (talk) 00:00, 11 August 2012 (UTC)[reply]

Electromagnetic waves, please help me!

When I was in high school (not much long ago, like 2 years ago), when teaching about electromagnetic waves, they just showed the direction and magnitude of the electric and magnetic field only along one line, which is in some sense a 1-dimensional picture of EM waves, while I wanted to know what the field lines look like. Needless to say, I was not satisfied. So what I did was visualizing a simple version of an antenna. Which was a negative and a positive charge oscillating and passing through each other when they meet. so then I could visualize what it looked like in 2D and 3D and I was very happy with it(http://en.wikipedia.org/wiki/File:Electromagnetic_Waves_visualization.png) (I didn't show that the "loops" get "bigger" as they move away, also, it's just the electric field...). The problem is, whenever in textbooks they want to explain an effect concerning EM waves, they use the simple one dimensional version (and of course that's the right thing to do!) and I just can't help thinking "what does this mean in 3D". I had the problem when learning about crystallography, and the problem still remains (i.e. I gave up), but what I have a problem with now is polarization of light. well, I first started by visualizing the polarized light itself in 3D (because again, the pictures are always in 1D) and I could get a rough idea by imagining two point charges rotating around each other, and of course http://www.youtube.com/watch?v=naaeDJLcxgs helped a lot to, so I think it looks kinda like Fusilli pasta, but I still can't get it fully.So, after loads of unnecessary information, here are my questions:

1. Reading about chirality, once it said that normal light contains waves oscillating in all planes, even if it's monochromatic. well, wouldn't the oscillations cancel out and there will be only one plane left? they're vectors after all! (forget about visualizing that!)

2. Does the electric/magnetic field lines of a light emitted from an ordinary source look like what I drew? if not, what does it look like? is it messy?

3. When light passes through an environment with chiral molecules in it, it polarizes. Well, assuming we are using an electromagnetic wave as simple as what I drew, how do the torus-like wave fronts of an ordinary wave turn into the (probably?) fusilli like shape of a polarized light? I can't visualize that.

Whenever I see the EM waves shown that way, I understand the explanations, and I just feel that what I learned is incomplete, mainly because I can't visualize it in 3D. So my last question is that is there an easy way to visualize it, or should I just give up?--Irrational number (talk) 19:47, 10 August 2012 (UTC)[reply]

Electromagnetic waves are complicated fields: they have two vector values for every point in space. Visualizing two vector-fields, overlaying each other, in 3 dimensions, is not easy. Recognizing, understanding, and correctly visualizing the time-varying nature of the fields is even more difficult. This is exactly why electromagnetic physics is taught using equations and mathematical formalism. The way the fields behave don't need to look right; they need to satisfy the correct form of Maxwell's equations (whatever that ends up looking like). With a computer, you can plot the field strength and render a vector representation, but for any nontrivial cases, the resulting drawing is very difficult to interpret. You can develop better intuitions about the geometries of electrodynamics by working lots of problems, and to some extent even by experimenting in a lab, but I wouldn't stress out if you're having difficulty visualizing the fields under dynamic conditions. Nimur (talk) 21:45, 10 August 2012 (UTC)[reply]

1. In terms of photons (and light fundamentally is made of photons), non-polarized light is made up of photons of different polarizations; in terms of electrical and magnetic fields, the polarization varies depending on location (on pretty small length scales).

2. E.g. incandescent lamp light (or similar thermal light sources, e.g. a glowing piece of coal) is produced by many atom-scale emitters due to thermal motion of electric charges, so it's more or less a superposition of many such dipole waves, and it's certainly messy.

3. Your dipole waves are linearly polarized. The plane of polarization is formed by the symmetry axis of your antenna and the position of the observer (a line and a point off the line define a plane). If you want circular polarization, take 2 waves with linear polarizations perpendicular to each other and one shifted by a quarter of the wavelength with respect to the other... this superposition is a circularly polarized wave.

Icek (talk) 23:03, 10 August 2012 (UTC)[reply]

psoriasis

how did they treat psoriasis before modern medicine? 1800's and before--Wrk678 (talk) 22:59, 10 August 2012 (UTC)[reply]

If you mean before modern drugs now currently used for psoriasis, I don't actually know, but since nobody else has answered, I can suggest a couple of likely candidates:-

I've had it for 50 years. 50 years ago a doctor prescibed an "ointment" which was actually pitch in a solvent, to be smeared on. It was messy, revolting, but it sort of worked a bit.

Psoriasis tends to go away in ultraviolet light. So, a pre-modern treatment could have been to go outside and expose the rash to the sun. In fact, some doctors still advise that today, with a caution against sunburn & skin cancer.

I have over the years found some home remedies that work to a certain extent, but we don't give that sort of advice here. Wickwack120.145.191.48 (talk) 03:03, 11 August 2012 (UTC)[reply]

The Old Philosopher, Eddie Lawrence, once said somethng about flagellation as a cure for psoriasis. Odds are good that he was joking. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:22, 11 August 2012 (UTC)[reply]

That would make them psorer.-- OBSIDIAN†SOUL 03:27, 11 August 2012 (UTC)[reply]

My mother's psoriasis was more or less completely relieved by traditional Chinese herbal medicine. It involved boiling a broth of, among other things, cicada shells and tree bark. She then drank the broth. It smelled god awful, but did the trick. 112.215.36.179 (talk) 04:57, 11 August 2012 (UTC)[reply]

Just wondering, is there any evidence that psoriasis was diagnosed 200+ years ago? (I was going to say, did people suffer from psoriasis 200+ years ago, but realised I meant something different.) --TammyMoet (talk) 08:50, 11 August 2012 (UTC)[reply]

The answer to that, is yes/no/maybe/maybe not. That's because psoriasis (a modern term) is actually a collection on various sorts of skin disease for which a cause is unknown, and that may or may not be related. The word psoriasis, root-wise, means "itchy skin" but most forms do not itch at all, or only itch due to inappropriate attempts to treat it. It is not at all unlikely that in earlier times, a bad case of psoriasis got diagnosed on the basis of appearance as early leprosy, which it is not. Diagnosis even today is problematical. In my case, 30 years ago I saw a skin specialist, who cut out a piece of skin and sent it to the lab. The lab's reply was essentially "It's abnormal, but we don't know what it is". The specialist's conclusion was "I don't know what it is, but it is probably a form of psoriasis." More recently, my regular doctor decided that with the advance of time, it was worth while getting another specialist opinion. The new opinion was the same as the first. Wickwack120.145.191.48 (talk) 10:54, 11 August 2012 (UTC)[reply]

Beetles common to England seem to come in very specific sizes?

I'm in southern England, and every few weeks, one's home is politely invaded by a single specimen of a black beetle about half an inch long. (I am, naturally, very confident that it's not the same individual coming back time after time.)

These beetles are particularly noticeable because they move around the house by walking everywhere quite slowly (including up several flights of stairs), and have difficulties with stability that result in them regularly getting stuck upside down on their backs. They react to this by waving their legs in the air vigorously in order to attract nearby humans, who will eventually get bored of watching, and therefore use a credit card to help the beetle get the right way up again.

Apart from this curious co-evolution with credit cards (how do the credit card manufacturers benefit from the relationship!?!), the strange thing about these beetles is that they are always the same size. You never see one that's a bit smaller or a bit bigger, as far as the untrained eye is concerned.

Pondering this problem, I remembered some distant fragments of high school biology, and considered the fact that perhaps these identikit beetles were instars of a particular beetle species, and that perhaps these beetles only undergo ecdysis at particular body sizes that look roughly the same size. Perhaps the preceding instar is too small to open my letterbox and climb through it (or however they get in?!?), and the succeeding instar is very rarely reached due to the instability problem. (Perhaps some humans are less friendly to stranded beetles than I am.)

I was even more enthused with this random theory when, while walking to my local Indian restaurant, I discovered, dragging itself apparently painfully across the sidewalk, an immense black beetle that looked identical to the standard issue beetles that I normally encounter, except for its size and being somewhat plumper. Now, it could have been a completely different species - for example a rhinoceros beetle, which would explain the slight proportional increase in girth - but that wouldn't explain why I'd never seen younger, smaller versions of rhinoceros beetles.

Is it plausible that instars might explain all these beetles looking roughly the same size to me? Is it plausible that the huge beetle was an individual of the same species that had managed to survive through a couple of extra instars? --Demiurge1000 (talk) 23:15, 10 August 2012 (UTC)[reply]

Yes. You are correct in that this is an instar, but it's the last one. While insects periodically undergo ecdysis as larvae and [usually] grow larger with each molting; once they reach adult stage, they do not molt anymore and hence are stuck to whatever dimensions their exoskeletons hardened into. Insects in this stage are known as imago. There is no "younger" and "older" once they reach this stage in terms of size, the misconception is largely because most people treat adults and larvae as different animals due to their very different appearances and life habits (e.g. treating caterpillars as pests, but ooh-ing and aah-ing at butterflies).

Insects with softer bodies and longer lifespans as adults may still increase in size depending on factors like food consumed or gravidity (termite queens being one of the best examples). But beetles, obviously, have one of the thickest exoskeletons among insects. Therefore, when you see similar-looking adults which differ greatly in size, chances are they are different species. However, some species do exhibit morphological variation among subspecies, or even within populations (and of course, there's sexual dimorphism as well).-- OBSIDIAN†SOUL 23:33, 10 August 2012 (UTC)[reply]

Ah, yes, my imaginative mind ignored the fact that all the common British wasps I've seen are approximately the same size too. Although everyone knows that's because they were made in The Wasp Factory. Right, back to the drawing board.

Oh, what was the big beetle then? An escaped pet? --Demiurge1000 (talk) 02:51, 11 August 2012 (UTC)[reply]

Oooh. That's one of those books by Banks I'll never read. Mostly because he wrote it without the "M." and it doesn't have spaceships. Anyway, if you were six years old and happened to be my niece, I'd tell you it was the daddy beetle. But chances are it's female and probably eats your house beetles for breakfast.-- OBSIDIAN†SOUL 03:16, 11 August 2012 (UTC)[reply]

So the same species as the others, then? If so, it probably got the idea from the big mummy alien trapped under Antarctica in a rather bad film. --Demiurge1000 (talk) 04:42, 11 August 2012 (UTC)[reply]

Hate cross-universe films. Anyway, seriously? Most probably not. A lot of beetles which belong to the same family look identical to our layman's eyes, differing only in size or something just as arbitrary, but they're really not. In your case, since you compared it to a rhinoceros beetle, I'm guessing your beetles were both scarabs?-- OBSIDIAN†SOUL 05:29, 11 August 2012 (UTC)[reply]

And yes, your hypothesis on Coleoptera and credit card coevolution is one of the greatest evidences of evolution. Scientists have discovered recently that credit cards may have ultimately evolved from sticks used to poke at strange terrifying bugs by neanderthals. They evolved to their present day form after a population bottleneck when early modern humans decided to put one of the strange terrifying bugs in his mouth and discovered they tasted just like chicken (raw chicken guts that is). They survived in scattered human populations which still found the strange terrifying bugs gross, evolving to various forms like pipes, canes, umbrellas, clubs, swords, and dowsing rods. All of which retained a form or another of their commensalistic relationship with overturned beetles. One branch developed into strangely dorsoventrally flattened forms with partial radial symmetry and metallic exoskeletons. Though they were not as effective in overturning beetles as their later more specialized descendants.-- OBSIDIAN†SOUL 23:53, 10 August 2012 (UTC)[reply]

They just squished them instead? How does that contribute to the symbiosis?!? --Demiurge1000 (talk) 02:47, 11 August 2012 (UTC) [reply]

A lot of symbiotic relationships originated from predation or parasitism. For example, our own cells still keep enslaved mitochondria they swallowed eons ago, which still refuse to give up their own DNA. Listen closely and you can hear them demanding civil rights.-- OBSIDIAN†SOUL 03:16, 11 August 2012 (UTC)[reply]

August 11

Hydroponic Corn

can or is corn or soy beans being grown in hydroponics ? — Preceding unsigned comment added by Idontbeliveit100 (talk • contribs) 00:23, 11 August 2012 (UTC)[reply]

Yes, as a quick Google search for hydroponic maize or hydroponic soy will quickly reveal. Tonywalton ^Talk 00:56, 11 August 2012 (UTC)[reply]

I find it hard to believe that can corn is grown hydroponically. A link would be nice. μηδείς (talk) 04:56, 11 August 2012 (UTC)[reply]

Oh, you were making fun of his oriental Engrish! nvm-- OBSIDIAN†SOUL 07:13, 11 August 2012 (UTC)[reply]

Almost any plant that grows on soil can be grown with hydroponics, it's the space that's the problem-- OBSIDIAN†SOUL 07:08, 11 August 2012 (UTC)[reply]

However, it's not always practical to do so. In the case of corn (maize), only a tiny portion of the plant is edible, and that doesn't sell for much, so it's probably not financially viable. StuRat (talk) 07:39, 11 August 2012 (UTC)[reply]

Portable train derailer

I was recently watching the film Unstoppable and I was a bit sceptical of the scene where the company tries to derail the train with an emergency portable derailer. In the film, some characters express doubt that it will work with a train as large and travelling as fast as CSX 8888. They turn out to be correct, as the train busts through. This film is based on a true story, and according to CSX 8888 incident, this scene is more or less accurate. If they were already willing to deal with the massive damage caused by derailing a speeding freight train with dangerous cargo, and there were prior doubts as to whether the derailer would work, why didn't they just rip up a few feet of track, rather than use the derailer? A stick of gelly would have done the job in 2 400ths of a second, so time probaby wasn't the issue. 112.215.36.179 (talk) 04:49, 11 August 2012 (UTC)[reply]

I don't know about the movie, but the real-life incident lasted two hours, according to our article. I suspect it might take a bit longer than that to get hold of "gelly" and figure out what to do with it. (Of course there are many other ways to derail a train.) Looie496 (talk) 07:03, 11 August 2012 (UTC)[reply]

Agreed. Time would be the problem. Removing rails takes equipment and men, and getting that all to the site takes time, and then it takes more time to do the work. I'd think parking a locomotive engine on the tracks might be the quickest way to derail a train, if you don't mind destroying it, along with the train. StuRat (talk) 07:35, 11 August 2012 (UTC)[reply]

How do you know that section of the movie mirrors real life? While it appears true the derailer did not work, this doesn't mean anyone involved in deciding or placing the device thought it it wouldn't work. Of course even if someone did think that, it does not mean they would have thought of proposing to blow up the train track. Given the time frames involved it would hardly be surprising if by the time it came to placing the thing, acquiring and using some sort of explosive would be 'difficult' at best, as Looie496 said you're perhaps overestimating how easy it would be to acquire and use particularly given the bureaucracy that I expect would be involved. Nil Einne (talk) 07:42, 11 August 2012 (UTC)[reply]

Nil, you appear to have suffered a seizure while typing that last sentence. Shall we call the paramedics for you ? StuRat (talk) 07:49, 11 August 2012 (UTC) [reply]

Apologies, typing on a mobile phone is not fun. I've since modified/corrected any errors in my above comment. Nil Einne (talk) 09:39, 11 August 2012 (UTC)[reply]

They had enough time to get the derailer there and install it, and also enough time to line up cops to shoot at some button. An oxytorch or even angle grinder could have made the tracks unusable in a minute, sooner with a few workers helping to destroy it. I don't know if anyone expressed doubt in reality, but I would think that the derailer has some sort of rating for weight and speed of the derailed train that might give some idea that it wasn't going to work. How common are these derailer thing anyway? I doubt they're the kind of thing you'd have lying around all over the place. You could also have quickly welded some scap to the track to make it unpassable. 112.215.36.177 (talk) 08:02, 11 August 2012 (UTC)[reply]

I doubt that any "derailer" actually exists. They would need thousands of them positioned all over the nation to have any hope of having them where needed, and there would be more of a risk of "the bad guys" using one than them being used by "the good guys". The line of cops shooting at a button is complete silliness too. Welding isn't all that quick, again considering the time needed to get the equipment and a welder. StuRat (talk) 09:07, 11 August 2012 (UTC)[reply]

Derails certainly do exist, and the fact they sourced and installed onein time to watch it not work illustrates my point that they had time to do something a bit more sure. Weldin equipment is prolific as are angle grinders. Welding isn't quick if you are trying to do a good job of it, but this is making a mess on purpose. 112.215.36.171 (talk) 09:28, 11 August 2012 (UTC)[reply]

(EC) Did either of you bother to read the Derail article which is linked from the article on the incident and the one on the movie (which the OP themselves linked to when starting this thread)? These things do exist and from the sound of it, they aren't uncommon, evidentally frequently (always?) used when a crew is working on the line so I presume likely something carried by most work crews. I have no idea if they usually have ratings, but again, I think the OP is overestimating how much analysis went in to what was seemingly one desperate idea sometime during the 2 hour stretch. Nil Einne (talk) 09:39, 11 August 2012 (UTC)[reply]

Obviously I have, since I linked to it. I'm not overestimating the thought, I'm asking if they could have done it better. The derailers are used in the yards, not at random points along the line where the attempted derailing was done, so they probably would have needed travel a fair way to get one. An oxytorch, tig or mig welder, or angle grinder was probably handy at that same yard and using it would probably have taken just as long as bolting on the derailer. 112.215.36.171 (talk) 09:52, 11 August 2012 (UTC)[reply]

To destroy railway lines in wars explosives just get thrown all over the lines, often from the air. There's no need for precise placement to be effective, but thinking about what you're doimg might help. If you stuck a grenade under the rail you should do a bit of damage by bending it upward. If you could get it at a join it could do even better.112.215.36.171 (talk) 09:45, 11 August 2012 (UTC)[reply]

And surely SWAT, the National Guard, the Army or other fast response unit could turn up a few grenades or better in a hurry. Even a gun store could have donated a cache of gunpowder. A chain attached to the track and pulled with a pickup might have been sufficient to distort the track enough. 112.215.36.179 (talk) 08:15, 11 August 2012 (UTC)[reply]

To attach a chain you'd need to drill a hole through the rail. This would take time, too. (If you just placed it under a tie, the tie would likely just break.) Good luck getting grenades from the Army in a hurry. Getting gunpowder, placing it properly, laying a fuse, etc., again takes time and expertise. StuRat (talk) 09:07, 11 August 2012 (UTC)[reply]

You can loop a chain or braided wire underneath the metal rail between the sleepers. You only need to move it an inch or so with a winch to make the rail unpassable. 112.215.36.171 (talk) 09:38, 11 August 2012 (UTC)[reply]

From a quick search, this whole thread may have been founded on false premises. According to [16] they may have been taking up rails further down the line. (It also suggests some people weren't surprised by the failure of the portable derailer given the speeds involved, but again this doesn't mean does actually involved had the same thoughts. It's somewhat unclear to me the expertise of those involved in making the decision and in placing the derailer.) Nil Einne (talk) 09:48, 11 August 2012 (UTC)[reply]

Thanks for that! 112.215.36.171 (talk) 09:58, 11 August 2012 (UTC) [reply]

Resolved

Microscope on Mars

Why has no Martian lander brought along a microscope? Since all but the smallest Earth organisms can be seen under a light microscope, and images of moving microbes is indisputable evidence for life, it would seem a much more logical choice than the astrobiological equipment Viking 1 and 2 brought along. --140.180.5.169 (talk) 06:35, 11 August 2012 (UTC)[reply]

Your premise is wrong. Spirit, Opportunity, and the Phoenix lander have all had microscopes. Unfortunately they haven't managed to get any moving microbes into them. Looie496 (talk) 06:58, 11 August 2012 (UTC)[reply]

I mean a high-powered biological microscope. Spirit and Opportunity's MI had a resolution of 30um/pixel, while Phoenix's limit was 16um/pixel. Curiosity's MAHLI does slightly better than 14um/pixel. These microscopes were designed to look at geological features, not life. Earth bacteria are typically a few micrometers in diameter, far below the resolution of even MAHLI, and there's no reason to expect potential Martian microbes to be much smaller. --140.180.5.169 (talk) 07:22, 11 August 2012 (UTC)[reply]

@@ Line 390: / Line 390: @@
 :Just wondering, is there any evidence that psoriasis was diagnosed 200+ years ago? (I was going to say, did people suffer from psoriasis 200+ years ago, but realised I meant something different.) --[[User:TammyMoet|TammyMoet]] ([[User talk:TammyMoet|talk]]) 08:50, 11 August 2012 (UTC)
-::The answer to that, is yes/no/maybe/maybe not.  That's because psoriasis is actually a collection on various sorts of skin disease for which a cause is unknown, and that may or may not be related.  The word ''psoriasis'', root-wise, means "itchy skin" but most forms do not itch at all, or only itch due to inappropriate attempts to treat it.  It is not at all unlikley that in earlier times, a bad case of psoriasis got diagnosed on the basis of appearance as early leprosy, which it is not.  Disagnosis even today is problematical.  In my case, 30 years agao I saw a skin specialist, who cut out a piece of skin and sent it to the lab.  The lab's reply was essentially "It's abnormal, but we don't know what it is".  The specialist's conclusion was "I don't know what it is, but it is probably a form of psoriasis."  More recently, my regular doctor decided that with the advance of time, it was worth while getting another specialist opinion.  The new opinion was the same as the first.  Wickwack[[Special:Contributions/120.145.191.48|120.145.191.48]] ([[User talk:120.145.191.48|talk]]) 10:54, 11 August 2012 (UTC)
+::The answer to that, is yes/no/maybe/maybe not.  That's because psoriasis (a modern term) is actually a collection on various sorts of skin disease for which a cause is unknown, and that may or may not be related.  The word ''psoriasis'', root-wise, means "itchy skin" but most forms do not itch at all, or only itch due to inappropriate attempts to treat it.  It is not at all unlikely that in earlier times, a bad case of psoriasis got diagnosed on the basis of appearance as early leprosy, which it is not.  Diagnosis even today is problematical.  In my case, 30 years ago I saw a skin specialist, who cut out a piece of skin and sent it to the lab.  The lab's reply was essentially "It's abnormal, but we don't know what it is".  The specialist's conclusion was "I don't know what it is, but it is probably a form of psoriasis."  More recently, my regular doctor decided that with the advance of time, it was worth while getting another specialist opinion.  The new opinion was the same as the first.  Wickwack[[Special:Contributions/120.145.191.48|120.145.191.48]] ([[User talk:120.145.191.48|talk]]) 10:54, 11 August 2012 (UTC)
 == Beetles common to England seem to come in very specific sizes? ==

Revision as of 10:59, 11 August 2012

August 7

Scientific article self-criticism

Sodium triphosphate alkalinity?

H2o2

bug identification

Proof crosswords help with any objective cognitive function

effect of exercise on cholesterol blood testing

mars rover

August 8

Snowflake uniqueness

Mars Science Laboratory average speed

What is happening to me?

Heater and refrigerator conflict

Why doesn't the Mars rover walk on legs?

One way human tripulated mission to Mars

Analog Alarm (Wrist) Watches

What is this insect?

Whiteboard that isn't

E=mc2

A new problem formed on my car at the auto dealer. Your thoughts?

This time, it involved shorted & melted wires under the driver's dash.

My first thought: "Is this an act of service center sabotage??"

August 9

Curiosity landing site ?= Pambotis Lacus?

Rocket vaporizing launcher pad/tower

is olive a citrus fruit?

Can flavor compounds and oils dissolve in saturated syrup if they won't dissolve in water?

How would all of Earth's electronics get shut down (as depicted on Revolution (TV series)?)

How would all of Earth's electronics get shut down (arbitrary break)

Earth-Moon orbit

August 10

Metal sorting

Doyère, binomial authority for Milnesium tardigradum and so on

Incremental cost of second Curiosity-like rover

(UK) approx. inch and a half long insect with a long thin sting, wasp colours but not a wasp shape

Year we would live on mars.

Living longer with a transplanted heart

Time manipulation

Electromagnetic waves, please help me!

psoriasis

Beetles common to England seem to come in very specific sizes?

August 11

Hydroponic Corn

Portable train derailer

Microscope on Mars

E=mc²