Wikipedia:Reference desk/Archives/Science/2012 April 15

= April 15 =

What is the big ball on most wheellock pistols?


Comparing a number of early firearms, I noticed that all wheellock pistols have a large ball at the end of the grip, while none of the flintlocks have it. What was the purpose of it? As wheellocks were a lot slower to reload than flintloks, were they used as maces? Then why didn't the flintlocks have it, as even they required at least 15-20 seconds to reload. Or was it strictly ornamental? Even in this case, why the difference between wheel- and flintlocks? --79.116.94.10 (talk) 12:29, 15 April 2012 (UTC)


 * Didn't that ball unscrew and have gunpowder stored inside? That's what I've always thought. When I've thought about it. Which isn't much, to be honest. --Kurt Shaped Box (talk) 12:41, 15 April 2012 (UTC)


 * According to the discussion under this video, "...the pommels at the end of the stocks secured them from being accidentely dropped in a time when﻿ thick gloves- often from steel- were worn."  Spinning Spark  12:44, 15 April 2012 (UTC)
 * ...and from Gun Digest I found "Incidentally, the ball on the end of the grip not only kept the hand from sliding off, but it opened up to make two hinged halves of a box holding spare pyrites and balls."  Spinning Spark  12:58, 15 April 2012 (UTC)
 * Thank you, it's even a plausible explanation for the difference: when wheellocks were used, they were used mainly by cavalry, and they wore full armor. When flintlocks became common, the infantry warfare changed completely, and cavalry lost its armor (maybe except the cuirass), so there were no steel gloves to worry about. --79.116.94.10 (talk) 13:58, 15 April 2012 (UTC)
 * All of the above may be true, but the most important reason is that it is a counter-weight makes the weapon balance in the hand. Note that the steel barrel, metal firing-lock and trigger mechanism are all forward of the handgrip which is only made of wood. It would be very front-heavy without something to balance it up. It serves a similar function to the pommel on a sword. Flintlock pistols were a little more balanced, but had a conterweight too, in the form of a big lump of brass at the end of the stock. "The walnut pistol grip stock has two checkered sections to grant a firm, comfortable and stable grip, thanks to the counterweight butt plate." More information about wheellock pistols is here. Alansplodge (talk) 19:11, 15 April 2012 (UTC)

I've heard that they were used as maces (or more of a club, really) and I've seen them on all manner of early pistols including flintlock, wheellock and percussion cap designs. Here is a picture of a flint lock that does have it. . 203.27.72.5 (talk) 21:12, 15 April 2012 (UTC)
 * Yes that's true too. Once you've fired it in a fight, it's pretty useless unless you've got time to mess about with reloading - if you've practiced a lot, about 30 seconds for a flintlock with pre-prepared catridges. So thumping your opponent with the heavy end is a good back-up. But it's still the balance thing that's the primary purpose. Even pistols without a large pommel are still going to have the butt filled with metal so that you can hold the thing up without a lot of stress. Alansplodge (talk) 23:10, 15 April 2012 (UTC)
 * I suppose the balance issue also explains why all of those oldtimey pistols have such a large angle (~135°) between the barrel and the grip as opposed to more modern pistols which have a much smaller angle (~90°) with a grip that also houses the heavy magazine. 203.27.72.5 (talk) 01:17, 16 April 2012 (UTC)
 * Yes, over the years, changing technology has enabled designers to bring the point main mechanism of the gun further and further back, doing away with the need for counter-weights. Alansplodge (talk) 22:07, 16 April 2012 (UTC)

Can a laptop battery improve?
I didn't use a laptop battery for some years, since it lasted just a couple of minutes when it was 4 years old. Today I started to use it again, and surprise, it lasts more than before. Can it be that it changed for better? 88.8.67.214 (talk) 16:13, 15 April 2012 (UTC)


 * I found with several examples that old rechargeable batteries can still have a charge after years of storage. But they always fail completely after one or two discharge-charge cycles.  Apart from nickel-iron batteries, all batteries suffer from slow chemical deterioration over time.  Ratbone120.145.195.178 (talk) 16:18, 15 April 2012 (UTC)
 * If it only lasted "a couple of minutes" it is likely it was not charged properly, or at all. Are you sure it was actually charging?  Most likely problem is with the power adapter (fuse blown, outlet not switched on etc).  If you were not actually monitoring on-screen you may only have thought you had charged it.  Spinning  Spark  17:04, 15 April 2012 (UTC)


 * I believe you sometimes need to fully discharge a battery for it to be able to fully charge again. This only works with certain types of rechargeable batteries.  I think it's related to the memory effect electrical hysteresis . StuRat (talk) 17:01, 15 April 2012 (UTC)


 * The chemical degradation of rechargeable batteries is entirely unrelated to electrical hysteresis. Our articles on the various types of rechargeable batteries address the reasons for their failure, and memory effect describes the reasons why batteries may sometimes require a deep discharge before charging.  TenOfAllTrades(talk) 17:09, 15 April 2012 (UTC)


 * Did it actually last longer or did the computer just say it would last longer? Because it's possible that by not being fully discharged, the computer became confused about how long it would really last.  But there's a Computing desk where there might be better answers. Wnt (talk) 02:39, 16 April 2012 (UTC)
 * Also note that the memory effect ONLY applies to nickel cadmium batteries, which haven't been widely used in electronics for a decade or so. Thus depending on how old your battery was, it is unlikely this applies. - Running On Brains (talk) 06:48, 16 April 2012 (UTC)
 * The article also describes a number of (more common) phenomena which are often mistaken for the 'true' nicad memory effect. TenOfAllTrades(talk) 12:41, 16 April 2012 (UTC)
 * Yes, but none of those other problems could be alleviated by a deep discharge. Unless I'm missing something. - Running On Brains (talk) 01:07, 18 April 2012 (UTC)
 * Just kidding, it looks like voltage depression could also be solved by deep discharge. - Running On Brains (talk) 01:09, 18 April 2012 (UTC)
 * ... but for a laptop battery, this is a tricky process involving dismantling the battery and dealing with each cell individually. It is not to be recommended unless you really know what you are doing.  Lithium batteries should never be deep discharged, in fact they usually contain circuitry to prevent recharging after an accidental deep discharge.    D b f i r s   06:57, 19 April 2012 (UTC)

Physics
Is such graph heat flux through insulator (P) depending on thickness of insulator(l) possible? P1:134,5W l1:0mm  P2:95W l2:1mm   P3:63.78W l3:2mm   P4:49,60W l4:3mm. Also, is it possible that the temperature of water changes for 20K when there is no insulator between metal vessel with hot water (55 degree celsius) and cold water (25 degree celsius)? This happened in first case(P1, l1). I had to made up these data because the experiment itself wasn't done correctly. Are heat flux values to high or are they possible? Please help, thank you in advance!--Atacamadesert12 (talk) 16:52, 15 April 2012 (UTC)


 * Your english is so garbled with data apparently missing that it cannot be answered. But it sounds like homework. Obviously the flow of heat (measured by Joules per second ie watts) through a substance inversely proportional to thickness and proportional to the temperature difference (measured in kelvins). This is Fourier's Law. Keit121.221.92.224 (talk) 02:02, 16 April 2012 (UTC)

GMO Docs
This isn't strictly science-related, but does anyone know of well-respected, informative documentaries on genetically modified foods? Specifically, I would like to see one documenting the environmental consequences thereof. Any ideas? 75.73.226.36 (talk) 19:26, 15 April 2012 (UTC)


 * The World According to Monsanto comes to mind. Parts of Food, Inc. is also about GMO. However please note that these films do not criticize GMO in general, but only the current implementation of GMO by certain unethical companies. I am not aware of any documentaries that deal with GMO in general. 99.245.35.136 (talk) 20:54, 15 April 2012 (UTC)


 * The Future of Food is another. StuRat (talk) 18:44, 16 April 2012 (UTC)


 * I'm really not sure those would count as "well-respected", they are so one sided as to just about qualify as anti-gmo propaganda. You could try the skeptoid episodes on organic food myths and organic vs conventional agriculture, they don't specifically address the environmental consequences but they might be a good primer.. The problem is that proponents of GMO will likely tell you that it's all fine while the critics will tell you it will lead to the apocalypse. The truth lies somewhere in between. GMO obviously has massive potential to help feed the planet, it all depends on how the risks are managed. Vespine (talk) 22:37, 16 April 2012 (UTC)


 * I agree. While they raise some valid points, those documentaries tend to go overboard on the alarmist side.  The most disturbing thing is that there never has been a public debate and referendum on how to handle GMOs, at least in the US.  It's all being decided "behind closed doors". StuRat (talk) 23:02, 16 April 2012 (UTC)


 * And if you haven't read them already, we have articles for Genetically modified food and GM food controversy.Vespine (talk) 22:41, 16 April 2012 (UTC)

loading dose question
why does the loading dose work shouldn't the same percentage of drug get cleared no matter what? — Preceding unsigned comment added by 71.125.255.62 (talk) 22:43, 15 April 2012 (UTC)


 * Loading dose is the article in question. Does Loading_dose explain it ?   If not, it might be useful to look at in reverse.  That is, with a drug that only slowly clears the body, you want a smaller maintenance dose on each subsequent day, only enough to replace that portion which has been cleared.  The "normal dose" (the amount we would give every day, if it quickly cleared the system) is only given on day 1, and this is what we call the "loading dose".  StuRat (talk) 22:48, 15 April 2012 (UTC)