Wikipedia:Reference desk/Archives/Science/2014 September 19

= September 19 =

Implicit comprehension
What is the term for a disability regarding the detection of implications, either in written or spoken language? Is it a type of pragmatic language impairment? Plasmic Physics (talk) 00:19, 19 September 2014 (UTC)
 * I hate this term but isn't Emotional intelligence related to this? Bus stop (talk) 00:42, 19 September 2014 (UTC)


 * Related on what level? I ask, because EI involves psychophysiological expression and perception, whereas the other involves the (mis)application of logic, i.e. reasoning. Plasmic Physics (talk) 01:10, 19 September 2014 (UTC)


 * Possibly, it could be a symptom of someone on the autism spectrum. Reading subtext and non-verbal communication, understanding the emotional state of others, etc. could all possibly be seen as "detection of implication" of one's actions on other people, which is a common symptom of autism.  -- Jayron  32  11:48, 19 September 2014 (UTC)


 * Plasmic Physics—at the article you link to, pragmatic language impairment, I find mention of "Hyperlexia", described as "a similar but different disorder where main characteristics are an above-average ability to read with a below-average ability to understand spoken and/or written language." But I'm not sure of its relevance. Bus stop (talk) 11:55, 19 September 2014 (UTC)


 * I can rule out hyperlexia, but I do think that the case which I'm considering is a autism spectrum disorder. I just don't know which one. Plasmic Physics (talk) 11:49, 21 September 2014 (UTC)

Sodium chloride
Big Sodium chloride crystals are transparent. If I melt and mould handful of table salt will I get a transparent piece or will it go opaque? Is there any way I can get a transparent salt piece of a very specific shape? 85.141.204.79 (talk) 14:32, 19 September 2014 (UTC)
 * Yes. You can make a big crystal and then carve it. Looie496 (talk) 14:43, 19 September 2014 (UTC)


 * Halite-249324.jpg's some instructions on how to make large NaCl crystals:, , . If you melt and mold it, it will likely crystallize into many small crystals, and be functionally opaque at the macroscopic level. Even if you managed to cool it slowly enough to get larger crystals, the resulting shape would not be well fitted to the mold. Carving/shaping a large crystal might work as a way to preserve translucence, but if you just hack at it with a knife or something you will initiate fracture mechanics and make crystal defect which will diminish translucence. SemanticMantis (talk) 16:29, 19 September 2014 (UTC)


 * Sodium chloride ingots for optical applications are made with the Kyropulos growth method: a seed crystal in a cooled holder is lowered until it touches the melt, the melt starts crystallizing, the crystal holder is slowly raised with the crystal growing underneath. See this supplier of optical materials, and this page for a short description of the process. It cleaves easily but I assume it can be machined with some care. Used mainly for infrared applications, people who build their own co2 laser sometimes use a salt crystal for the window through which the laser beam exits. Ssscienccce  (talk) 14:02, 20 September 2014 (UTC)

Chocolate causes sweat, after surgery? Why?
I was through a minor surgery 2 years ago that permanently affected my nervous-system, mainly in a good way, but I also got the strangest symptom ever..

Immediately after the surgery, -and ever since- whenever I eat chocolate, my forhead, temples and to a lesser degree my scalp immediately start sweating. This seems to be especially the case with very dark chocolate and my forehead gets literally soaking wet in a matter of seconds. But once I stop eating chocolate, I stop sweating again and dry up... as dry as ever. I had never experienced this before the surgery.

I can't really say that this affect my life-quality, (Maybe it's even a blessing in disguise which makes me stop eating choc :P), but I'm just very puzzled as to why this happens..

Is there something in chocolate that potentially could bring out symptoms like these in some people?

I realize this must be one of the weirdest questions asked on Wikipedia... ;)

2A02:FE0:C711:5C41:D960:1821:2C23:C009 (talk) 17:46, 19 September 2014 (UTC)
 * If you are asking us why you are having a biological reaction to something, perhaps you should ask your doctor instead. I am sure someone immediately below will try to provide you with some medical advice.  They shouldn't, per Wikipedia's own rules.  So, ask your doctor why you do this.  They can tell you.  -- Jayron  32  18:03, 19 September 2014 (UTC)


 * I second the advice to check with your doctor--we cannot and should not provide any medical advice at the reference desk. For the general phenomenon of sweating after eating, wikipedia has a stub on Gustatory hyperhidrosis. --Mark viking (talk) 18:44, 19 September 2014 (UTC)

I wasn't really asking for 'advice', I was wondering if chocolate might contain something that could cause such symptoms in some people. So just checking for possible explanations. A longshot perhaps, but a simple question anyhow. Not asking advice as to what to do or anything. It's not like it's the end of the world, although it is a minor nuisance. I could of course approach the clinic where I was... if I really want to find out. 2A02:FE0:C711:5C41:D960:1821:2C23:C009 (talk) 18:50, 19 September 2014 (UTC)

By the way, that link you gave me, Mark, was a good one for me. Thanks. 2A02:FE0:C711:5C41:D960:1821:2C23:C009 (talk) 18:52, 19 September 2014 (UTC)


 * Chocolate has a fair bit of caffeine in it, which is a stimulant. See the Effects section of each, particularly the circulatory ones. If you drink coffee, do you feel something similar? InedibleHulk (talk) 20:30, 19 September 2014 (UTC)
 * To be picky, just because I can, the stimulant more specifically associated with chocolate is theobromine, which is closely related to caffeine but has one fewer methyl group. The name comes from "food of the gods".  Chocolate also has some theophylline, which like theobromine is a dimethylxanthine, but with the methyl groups in different spots. --Trovatore (talk) 20:40, 23 September 2014 (UTC)


 * Look up hyperhydrosis and inquire with your doctor. For all we know, you may be about to combust spontaneously. μηδείς (talk) 23:59, 19 September 2014 (UTC)

Question (Women and chains)
How long would a 12mm short link stainless steel chain have to be before an average Caucasian woman would be unable to pull the chain along an even concrete surface due to its overall weight along its length? — Preceding unsigned comment added by IkarosMyAngel (talk • contribs) 18:17, 19 September 2014 (UTC)


 * There will be so many variables that an experiment would be the best way to find out. Some of the variables:


 * 1) Is chain well lubricated, dry, or rusty ?


 * 2) What angle is it being pulled ?


 * 3) Temperature ? (will affect viscosity of oil on chain)


 * 4) Does it start in motion or still ? (dynamic versus static coefficient of friction).


 * 5) How far does she have to move it ?


 * 6) How does she grip it ? (wrapping it around her arms a few times might be best) StuRat (talk) 18:23, 19 September 2014 (UTC)


 * This page says that such a chain would weigh ~3.4 kg/m. For a rough estimate, consider that 50 m of this chain would weigh ~375 lbs (and cost about US$ 571). I suspect some people could drag that, some couldn't. If you want to look up figures for average strength, find this book: Boff, K.R., et al (Editors) Handbook of Perception and Human Performance Wiley-Interscience, 1986. SemanticMantis (talk) 19:31, 19 September 2014 (UTC)


 * Define "average Caucasian woman". ←Baseball Bugs What's up, Doc? carrots→ 22:02, 19 September 2014 (UTC)


 * See here. Count Iblis (talk) 03:35, 20 September 2014 (UTC)


 * 12mm. μηδείς (talk) 23:56, 19 September 2014 (UTC)


 * I added a better title. StuRat (talk) 00:21, 20 September 2014 (UTC)


 * The coefficient of friction of steel on smooth concrete is just under 0.5, so the 50m chain suggested by SemanticMantis would require a pulling force of around 180 pounds. Most women would struggle with this.    D b f i r s   00:46, 20 September 2014 (UTC)


 * You don't have to pull the entire chain uniformly. You put it on the ground in a coiled up way, move part of it forward, go back, move another part etc. etc. That way you can make the required force arbitrarily small, at the price of having to move back and forth a lot more (the total amount of work performed against the friction force stays the same). Count Iblis (talk) 03:32, 20 September 2014 (UTC)

pureWash system
See. This claims it cleans laundry by oxidizing clothes without using bleach or heat. It says it uses 25 watts. So what exactly is it doing, creating ozone and bubbling that through the laundry ? Do we have a general article on this method ? StuRat (talk) 18:18, 19 September 2014 (UTC)


 * Consumer Reports states that it "inject[s]ozone into the cold wash water," and that it doesn't really work. - EronTalk 18:38, 19 September 2014 (UTC)


 * Thanks. I suspected it was ozone, as that would explain why they wouldn't mention it, since it's a respiratory irritant (but then, so is bleach).  I wonder if the system just doesn't have enough ozone to work, or if no amount would clean clothes well. StuRat (talk) 21:43, 19 September 2014 (UTC)
 * Indeed. I would have thought that ozone would count as "bleach" for the purposes of advertising regulations, but presumably they just mean it doesn't use sodium hypochlorite. Tevildo (talk) 08:41, 20 September 2014 (UTC)
 * That being said, washing one's clothes without detergent is effective if they're not too dirty, and does give the benefits listed in the advert. One can save $297 straight off!  See Laundry ball and this 1997 article from SDMB. Tevildo (talk) 08:51, 20 September 2014 (UTC)

Glass powder
Apart from sandpaper production what are the possible applications of glass powder? 85.141.204.79 (talk) 21:05, 19 September 2014 (UTC)


 * It also gets used in potting mix. Recylcers may crush mixed broken glass to make this. Graeme Bartlett (talk) 21:26, 19 September 2014 (UTC)


 * Vitreous_enamel. SemanticMantis (talk) 21:30, 19 September 2014 (UTC)


 * 1) It's a convenient starting point to make molded glass parts.


 * 2) You might coat something with glass powder to increase friction. I think sand is used for this in roads, at times.  And quartz sand is essentially the same as glass powder, just larger grains.


 * 3) An abrasive polishing agent. StuRat (talk) 21:37, 19 September 2014 (UTC)


 * Glass is not used as abrasive and thus to make sandpaper. Its not hard enough. The most common used abrasive is corundum which is aluminium oxide. granular glass is only commonly used in chemical industry. --Kharon (talk) 04:21, 20 September 2014 (UTC)


 * Quartz glass is certainly hard enough to sand wood. StuRat (talk) 22:47, 20 September 2014 (UTC)


 * See Silica fume and Fumed silica. The latter has many applications.--Srleffler (talk) 07:53, 20 September 2014 (UTC)


 * It's also used to make a special paint (not the same as enamel) for painting features such as faces onto stained glass windows. It's also used to make manja for kite fighting.--Shantavira|feed me 08:15, 20 September 2014 (UTC)


 * Crushed recycled glass can be used as an aggregate in road construction and has properties "similar to natural sand and gravel".  Alansplodge (talk) 11:38, 20 September 2014 (UTC)


 * Match box strike pads: The striking surface on modern matchboxes is typically composed of 25% powdered glass or other abrasive material, 50% red phosphorus, 5% neutralizer, 4% carbon black, and 16% binder; Ssscienccce  (talk) 13:19, 20 September 2014 (UTC)