Wikipedia:Reference desk/Archives/Science/2016 September 9

= September 9 =

does air float on water?
InvisiblieMaki (talk) 10:01, 9 September 2016 (UTC)==
 * The density of air is 0.001225 g/cm3 according to that article. The density of water is about 1 g/cm3, or 1000 times as dense as air.  That information should be enough to answer your question.  -- Jayron 32 11:50, 9 September 2016 (UTC)
 * I am having difficulty not giving snarky answers to this question... Certainly a non-negligible amount of air will dissolve in the water and become the saviour of many fishes, but most of it will indeed stay quite happily above the water and not under it. Double sharp (talk) 12:51, 9 September 2016 (UTC)
 * Dissolving and floating are distinctly different concepts. See Buoyancy and Dissolution (chemistry). -- Jayron 32 14:41, 9 September 2016 (UTC)
 * I know that perfectly well (see the second half of my answer, although I appreciate that it could certainly be misconstrued), but felt like giving a little more detail. Double sharp (talk) 16:01, 9 September 2016 (UTC)

Short answer is "no"; if you have a compact mass of water, and set it free in the Earth's atmosphere, it will fall down since the air's density is lower than the water's. However, clouds are actually made of liquid and/or solid water, and yet they "float". According to this link (not sure that is a scientifically ironclad reference, but it matches my remembering of the answer to the question), the reason is that for very small droplets in aerosols, the weight is negligible compared to aerodynamic phenomena. Clouds do "float" above the ground, by not by the same mechanism as boats, ducks etc. float in water.


 * Well, yes, if you have a large bubble of air, it will float up, assuming no tricks (Earth's gravity, relatively pure water, air taken from the Earth's atmosphere). The reason is that while Earth pulls the mass of air down by gravity, the differences of pressure in water pushes it up more by buoyancy. See bubbles in sprinkling water or champagne (although that is Carbon dioxide, not air). Tigraan Click here to contact me 15:08, 9 September 2016 (UTC)


 * A fun generalization of this question is whether any liquid could float on a layer of any gas whatsoever. Which reduces largely to a hunt for the densest possible gas.  Reading non-reliable sources in a search I'm seeing things suggested like uranium hexafluoride (but it has too high a boiling point for STP), tungsten hexafluoride, radon (yeah, it's beyond nasty, but it's a gas), hexafluoropropane, octafluoropropane with alleged density of 10.3 kg/m3.  A curious thing about the answers I see is that almost every one is different, so I am less than convinced this is at all the limit.  But to give a comparison, water is of course one kg per liter = 1000 cc, so 1 m3 would be 1000 kg.  Can we find a liquid with a density less than 1.03% that of water?  Well, Straight Dope says that liquid hydrogen has a density of 0.07, and all concerns about its low temperature aside, that's still 7 times higher than we need it to be.  This seems far enough that it seems impossible, close enough that it *might* be possible, but we're going to need some big advance.  Is it possible to design a very large compound with a pattern of surface charges and hydrophobicities so cunningly incompatible (along the lines of superhydrophobicity, but self-directed) that it will not liquefy and remain a gas?  Well, I doubt it but I don't know.  Somebody go out there and invent the coolest thing since Silly Putty for me, willya? Wnt (talk) 21:53, 9 September 2016 (UTC)
 * Is octanonacontanonactanonaliafluorooctanonacontanonactatetraliane a gas? Sagittarian Milky Way (talk) 01:56, 10 September 2016 (UTC)
 * Absotively posilutely so. The gaseous state would only be obtained by alternate distillation and Dynamisation of a mixture of Phlogiston, Luminiferous aether and Orgone if this were susceptible to the process of succussion (see Hahnemann Conspectus adfectuum spasmodicorum aetiologicus et therapeuticus) while Jupiter aligns with Mars but, of course, not if it's Sunday. AllBestFaith (talk) 13:06, 10 September 2016 (UTC)


 * This could also be taken as a language Q (although then it belongs on the Language Desk). That is, would the word "float" normally be used to describe a lighter gas above a heavier liquid ?  I would have to say no, as "float" seems to be used mainly to describe solids on top of liquids.  See float. StuRat (talk) 14:46, 10 September 2016 (UTC)


 * Oil floats on water. Sagittarian Milky Way (talk) 15:30, 10 September 2016 (UTC)


 * True, it's also used for liquids on top of liquids, but the term doesn't much seem to be used for gases on top of liquids. StuRat (talk) 22:24, 10 September 2016 (UTC)

Oxybutynin
Hi, When I type in 'Oxybutynin' into Wikipedia it comes back with a great summary. In the Adverse Effects section it cites: These are dose-related and sometimes severe. In one population studied—after six months, more than half of the patients had stopped taking the medication because of side effects and calcium defects. An intake of calcium of 800 to 1000 mg is suggested.[citation needed] Dry mouth may be particularly severe; one estimate is that over a quarter of patients who begin oxybutynin treatment may have to stop because of dry mouth.[citation needed]

Is there any way of finding the article/paper this came from please? It just says citation needed. Many thanks Sally Nicholson — Preceding unsigned comment added by 194.74.94.243 (talk) 10:38, 9 September 2016 (UTC)
 * If you click the "View history" tab at the top of the article, you can see ALL of the edits made to that article. Then you can find who added the information to the article and contact them directly using the "talk" link next to their name.  -- Jayron 32 11:48, 9 September 2016 (UTC)
 * The "[citation needed]" means that the basis for the statement isn't obvious, and that another editor either doubts that it is true or at least wishes to verify that it is true. Literally, someone needs to find a source and cite it. If you do, please add the cite to the article so that others will be able to verify the statement as well. DMacks (talk) 21:03, 9 September 2016 (UTC)
 * User:Porkchopmcmoose added some of those ideas, and User:207.180.142.137 did another. There are two cites in the nearby list of side effects, including a cite for a list that mentions dry mouth. But I don't have access to that actual reference material to see how much detail it has, or if it in turn cites other studies. DMacks (talk) 21:28, 9 September 2016 (UTC)
 * User:Porkchopmcmoose added some of those ideas, and User:207.180.142.137 did another. There are two cites in the nearby list of side effects, including a cite for a list that mentions dry mouth. But I don't have access to that actual reference material to see how much detail it has, or if it in turn cites other studies. DMacks (talk) 21:28, 9 September 2016 (UTC)

Do fish, prawn, shrimp and aquatic animals feel pain like land animals?
I read in one science magazine that insects don't feel pain as they don't have spinal cord. I know that all land animals and birds feel pain like humans. I used to think fish, sharks, which have red blood feel pain. But this article says that they don't

I think crabs, prawns and other crustaceans don't feel pain. -- Marvellous Spider -Man 14:35, 9 September 2016 (UTC)
 * Wikipedia has an article titled Pain in crustaceans. -- Jayron 32 14:37, 9 September 2016 (UTC)


 * "Nociception has been documented in non-mammalian animals, including fish and a wide range of invertebrates, including leeches, nematode worms, sea slugs, and fruit flies." Each of those has a reference cited in the article. See also pain in fish. Short version: pretty much any animal a scientist has every studied carefully has something that we can consider pain. SemanticMantis (talk) 17:31, 9 September 2016 (UTC)


 * Paging, who I believe knows about this stuff. --Floquenbeam (talk) 17:37, 9 September 2016 (UTC)
 * First, a bit of terminology. Imagine burning your finger on a hot-plate.  You will immediately withdraw your finger, but you have done this without being conscious of the heat.  This is called nociception and serves to reduce any further injury.  It is a reflex, which in vertebrates, is controlled by the spinal chord, and does NOT involve conscious control by the brain.  However, a few seconds short time later, you will start to feel a burning sensation in the finger.  This subjective experience is pain, which does involve the brain.  Few scientists in the subject would dispute that fish, birds, reptiles, amphibians, crustaceans and many other invertebrates show nociceptive responses, but the debate begins when we ask do they feel pain.  Many of these animals have the neuroanatomy (receptor cells, nervous system and ganglia (simple brain)) which we would associate with being needed for the experience of pain.  Furthermore, they show behaviours associated with pain such as protecting the injured part of the body and avoiding the stimulus/location in the future.
 * The central problem here, and the answer to the OP, is that pain is a private, individual experience. I can not prove that what you experienced when you burnt your finger on the hotplate is the same experience I have when I do the same thing. So, scientists tend use argument by analogy or using sets of criteria when looking at the question of whether non-human animals experience pain.
 * You may wish to read Pain in invertebrates, Pain in crustaceans, Pain in fish, Pain in amphibians and Pain in animals. DrChrissy (talk) 18:12, 9 September 2016 (UTC)
 * You say that "a few seconds later, you will start to feel a burning sensation". In my fifty some years of experience that is not true. If the damage is immediate like that with a paper cut, there an immediate sharp pain (and I have been burned on the tongue by food that is way too hot, on my hands when cooking it, by the hot sparks from fireworks, and by the tips of soldering irons (accidentally and deliberately... so I don't have to imagine what it is like). --Modocc (talk) 18:44, 9 September 2016 (UTC)
 * When I said "a few seconds later", please do not take this too literally. The point is that the body may react with a reflex  to stimulation of the nociceptors before there is a sensation of pain created in the brain. DrChrissy (talk) 18:56, 9 September 2016 (UTC)
 * This has to be true in the trivial sense that the sensation will reach the spinal cord before it reaches the brain. I'm not sure how much further we can go about pain than that.  The key hold-up everything revolves around is qualia, a paranormal phenomenon that IMHO has no meaningful scientific explanation.  Indeed pain itself, as in pain that is really felt rather than, say, a drink robot making a warning noise in response to being kicked, is a purely paranormal concept based on a belief in the soul, atman, or similar corresponding phenomenon. Wnt (talk) 21:30, 9 September 2016 (UTC)


 * Yes, well the "few seconds" later comment struck a raw nerve, but it was obvious what Dr Chrissy meant, except to those of us who are robots or invertebrates, like certain presidential candidates, who only respond when told. But come on, folks, Jill Stein is obviously a self-conscious being functioning on the conceptual level.  Having been a cook at Denny's as I (under)majored in Bio. and Phil., I find the premise tendentious. μηδείς (talk) 23:03, 9 September 2016 (UTC)
 * @Wnt, there is also the problem of the functional significance of pain. Yes, it helps us and non-human animals (I'm a believer!) to protect an injured part of the body, but I think most of us have experienced pain from an injury that has long-since healed.  What is the point of that! DrChrissy (talk) 23:13, 9 September 2016 (UTC)
 * Could just be a spandrel right? Not every trait is an adaptive trait. BTW, on the nociception vs. pain bit - most bugs will happily walk around after having 1/2 of a leg removed, showing no tendency to protect or favor the injured leg(s). Here is a famous experiment that involved removing lots of ant legs, while also gluing lots of stilts to other ants. Must have been a fun job for some lab tech :D SemanticMantis (talk) 23:26, 9 September 2016 (UTC)
 * I think that link should be Spandrel (biology). The medical profession generally seems to believe that chronic pain has no function and it's considered a disease (I did have a reference for chronic pain as a disease but unfortunately it's blacklisted).  Richerman    (talk) 23:58, 9 September 2016 (UTC)
 * @SemanticMantis - yes, I am aware of these sorts of studies. However, there is evidence that some invertebrates will show protective responses - see Pain in invertebrates.  There are evolutionary reasons why animals may sometimes not exhibit behaviour indicative of pain.  Prey animals will sometimes avoid showing pain because this would make them a potential target for predators. I remember seeing a video of a steeplechase horse race.  One of the horses clearly broke its leg going over a jump, yet it carried on running with the other horses.   Perhaps adrenaline levels were so high they masked the pain, perhaps it was the motivation to remain with the other horses - I really don't know. DrChrissy (talk) 18:27, 10 September 2016 (UTC)


 * Wnt says above that qualia may not have a scientific explanation. However, I think that one should first try to get to a scientific explanation before giving up. So, from a reasonable scientific point of view we are always going to be "just machines", the details of how we are implemented cannot reasonably play any role (other than to define what we are). So, in principle you can upload a person to a virtual world implemented by a computer, it will then experience pain if his/her virtual finger is hit by a virtual hammer in exactly the same way as when his/her real finger would be hit by a real hammer, it doesn't matter at all if the computer is an analogue device implemented by wheels and gears. We're thus led to define qualia as algorithms. One may speculate that Wikipedia feels pain if a vandal comes along and Admins need to do a lot of work reverting the damage done. The system that feels pain here is then the system comprising of the servers and the people who edit here. Count Iblis (talk) 03:29, 10 September 2016 (UTC)


 * The assumption that invertebrates can't feel pain because they lack a spinal cord seems poorly thought out. Nerves can still extend to the brain, without following a central spinal cord.  Or, for that mater, the "brain" can be distributed, not in a single location.  Starfish are an example of this.  See starfish.  Note that I'm not arguing for or against invertebrates feeling pain, just commenting that we can't assume they don't due to the lack of a spinal cord or even a centralized brain. StuRat (talk) 22:36, 10 September 2016 (UTC)
 * Indeed. Another example is the octopus which has both a centralised brain, but also ganglia associated with each arm. Each arm can function in a limited way independently of the others, with no input from the centralised brain. We have an article Pain in cephalopods which I forgot to mention earlier. DrChrissy (talk) 23:35, 10 September 2016 (UTC)
 * As a meta-issue, a study of this nature does not allow serious conclusions to be drawn, and might (and typically do) have biasing influences. I think pain is one of the most poorly understood physiological phenomena in humans (along with consciousness), let alone other creatures.  But notice that the article does not directly say "Fish do not feel pain" (as the OP seems to have taken it), only that "Fish do not feel pain the way humans do".  Saying that they are not neurobiologically identical to humans does not say that any equivalent is absent.  Think of some old perceptions about enslavement of other races: they can't understand what I say = they're dumb and they have no feelings, so it is okay to do anything to them without empathy.  What is really happening is that we are trying to use our lack of knowledge about something as evidence of the absence of something that it suits us not to have to consider.  —Quondum 18:43, 11 September 2016 (UTC)
 * I agree. It is very convenient for us humans to deny that (some) non-human animals can experience pain, or something analogous to that.  Differences in neurobiology and physiology between taxa can be very misleading.  Insects have compound eyes which bear no resemblance whatsoever to human eyes.  Although they might not perceive images in the same way humans do, this does not mean they can not "see". DrChrissy (talk) 21:04, 11 September 2016 (UTC)

Terminology for benign self-induced vertigo or dizziness simply by spinning
A follow-up for Reference desk/Archives/Science/2013 September 2 which doesn't seem to adequately address the issues:

This is not intended to be a medical question as such. I was looking over the "Vertigo" and "Dizziness" articles and can find nothing but an extremely brief mention of what (to me) is the entirely harmless physiological effects from rapidly spinning oneself (say, on foot or in a swivel chair) for about 15 to 30 seconds, suddenly stopping, and experiencing maybe 15 to 30 seconds of (AFAICT the symptoms of) vertigo, which, of course, wears off completely. Even as a reasonably healthy middle-age adult, I may indulge myself this way (after a period of physical exertion) to expend surplus adrenaline; and hey, that all-natural high makes me feel like a kid again(!). (Needless to say, I would NEVER EVER endorse such an activity to ANYBODY with ANY SORT of equilibrium-related medical issues!)

I wonder: Is there another appropriate physiological term for this entirely benign and temporary sensation, other than "vertigo" or "dizziness" (and certainly not "motion sickness"), which does not connote underlying medical conditions and/or drug-induced causes? (And, yes, I already know of the motion-induced effects of the inner-ear vestibular system.) DWIII (talk) 15:58, 9 September 2016 (UTC)


 * Seriouly? It's called getting yourself dizzy. This should probably just be deleted as trolling, given the number of obvious "I HERE TROLL" BS we've been getting. μηδείς (talk) 23:09, 9 September 2016 (UTC)


 * The possible terminology includes Benign Labyrinthitis, equilibrioceptual disturbance, also Vestibulo–ocular reflex disturbance. The impairment in spatial perception and stability commonly called Dizziness can refer to vertigo, presyncope (Lightheadedness) or disequilibrium. AllBestFaith (talk) 12:02, 10 September 2016 (UTC)


 * The term postrotatory nystagmus is sometimes used - but that refers to the consequent nystagmus, rather than to the vertigo itself (Googling postrotatory vertigo yields very few instances of that exact expression). --catslash (talk) 15:13, 10 September 2016 (UTC)


 * I also see there's early stage positional alcohol nystagmus due to mild ethanol intoxication. An interesting if minor point of commonality there...  DWIII (talk) 12:41, 14 September 2016 (UTC)


 * I'm quite serious; I apologize if it came across as needlessly frivolous. I'm only just looking for any objective information on what could be considered commonly experienced (dare I say normal) subjective sensations to various external stimuli, without dredging up the presumed existence of underlying disorders.  An analogy:  optical illusions.  Surely, experiencing an optical illusion is not immediate grounds for declaring a person's vision is defective; it's just the way that the human eye-brain system is "wired up".  Knowing the formal terminology for this kind of thing is helpful to me for digging up the proper info I've been searching for; my thanks to the others for the considered responses so far.  DWIII (talk) 23:00, 10 September 2016 (UTC)
 * You may add to your list a resonant example of the advance of modern medical terminology that is the symptomatic identification of silent but deadly postprandial gaseous abdominal distension. AllBestFaith (talk) 23:55, 10 September 2016 (UTC)
 * I'd suggest ignoring the comment from μηδείς above. Must be having a bad hair day (again); this is not the kind of pointless adversarial attitude that interested enquiries should be encountering.  —Quondum 18:54, 11 September 2016 (UTC)

Notations in distributions
Does anyone know what is the significance of Ne and Nm from the formulae of charge and mass distributions from Electron magnetic moment?--82.137.12.230 (talk) 20:33, 9 September 2016 (UTC)
 * In many contexts, that notation would imply the charge density and the mass density. Sometimes, the capital letter means bulk (or "average") density, rather than interpreting density as a function of position.  But, unless these terms are defined, it's impossible to know what the author intended them to mean in this specific case.  Do we have a citation for these specific equations in this article, or are these simply mysterious equations with undefined terms that some anonymous editor wrote some time long in the page's historical past?  Nimur (talk) 21:17, 9 September 2016 (UTC)
 * I'm trying to identify the editor who has inserted the formulae from article's history.--82.137.10.236 (talk) 21:37, 9 September 2016 (UTC)

1 — Preceding unsigned comment added by 31.130.141.63 (talk) 22:41, 9 September 2016 (UTC)

Relativity Simultaneity
https://en.wikipedia.org/wiki/Talk:Relativity_of_simultaneity#Second_diagram_from_top

I didn't satisfied by the answer in the aforesaid link therefore can somebody explain why there is only one grey light cone is shown when there are 3 time axises and 3 space axises. Shouldn't there be two more light cones for the other time axises and space axises (ct',ct"-x',x") for the observer in grey light cone?162.157.217.155 (talk) 22:45, 9 September 2016 (UTC)eek


 * The other light cones aren't shown because the artist chose not to draw them, presumably to avoid making the diagram more cluttered than it needed to be. Someguy1221 (talk) 22:55, 9 September 2016 (UTC)
 * Oops, I seem to have been wrong. Someguy1221 (talk) 03:22, 11 September 2016 (UTC)

Ok, but would the bases and apothems of those missing light cones in diagram for whatever reasons have effect on the relativity simultaneity if drawn with different colours? - asking just for satisfaction. — Preceding unsigned comment added by 162.157.217.155 (talk) 03:04, 10 September 2016 (UTC)


 * All 3 light cones are exactly identical. That's a direct consequence of postulate 2 found near the top of the Special relativity article: The speed of light in vacuum is the same for all observers. Icek~enwiki (talk) 22:38, 10 September 2016 (UTC)

Of course all 3 light cones are identical but IMPOV observer in the grey light cone sees that the times-axis of his cone is vertical while oblique (bases, time axises and apothems) for observes in other 2 frame of references vice versa unless i am thinking wrong.162.157.217.155 (talk) 03:06, 11 September 2016 (UTC)eek


 * Yes, to the stationary observer, the other observers have oblique axes of time. Length contraction means the space-axis has to shift, to put objects closer to one another in the other frame. And the time axis will also shift, since everything is also occurring at a different time early or later depending on the relative direction of motion. Basically, both axes have to change, because both time and space coordinates change, except for the origin. Someguy1221 (talk) 03:22, 11 September 2016 (UTC)

Thanks for the reply Someguy. Everything is happening on the surface of light cone. 3 light cones means 3 different bases (surfaces) therefore would they still be able to see each other when everything is happening on surface of cone if each perceives that the axes his cone is vertical and the other’s are tilting including bases / surfaces of cones? imagination is Ok but a diagram of all 3 light cones will make it clear. 162.157.217.155 (talk) 04:11, 11 September 2016 (UTC)eek

Here is scenario Someguy if interested.

Please click on the link for the following timings. https://www.youtube.com/watch?v=lVuF5zrwMLY

Please also see the diagram on right for light cones if not wrong.

Albert’s prospective:

@ 3:59; vertical line represents the fixed point, x = 0 at different times in his frame of reference

@4:10; horizontal line represents simultaneous time at different places, t = 0

Galileo’s prospective:

Although moving but his frame of reference would be static for him but not for Albert, therefore

@4:51; vertical line represent the fixed point, x’=0, in his frame of reference at different times – horizontal line represent simultaneous time at different places, t = 0

@4:35; now let the time bubble (event) starts at t1 where vertical (x=0) and oblique (x’=0) lines meet and pause the event at any time t2. Diagram on the right (if not wrong) shows two light cones (LC) w.r.t Albert and Galileo such that their apexes are at t1. Apothems of their cones represent the light like curves.

Albert’s light cone: Albert sees that

1-The axis of his cone is vertical (oblique for Galileo)

2-Surface of his cone is horizontal or perpendicular to the axis of his cone (oblique for Galileo or tilting backward)

Therefore Albert thinks that

1-The axis of Galileo’s cone is oblique (tilting forward)

2-The surface of Galileo’s cone is also oblique (tilting forward) or perpendicular to the axis of Galileo’s cone

Galileo’s light cone: Galileo sees that

1-The axis of his cone is vertical (oblique for Albert)

2-Surface of his cone is horizontal or perpendicular to the axis of his cone (oblique for Albert or tilting forward)

Therefore Galileo thinks that

1-The axis of Albert’s cone is oblique (tilting backward)

2-The surface of Albert’s cone is also oblique (tilting backward) or perpendicular to the axis of Albert’s cone

As it can be seen clearly that the event on the surface of tilting cone is well below the surface of vertical cone therefore how come Galileo and Albert see each other. Similarly, I don’t understand why the surfaces of aforesaid both cones always coincides with each other for simultaneity when their axis are not - its just a tentative draft?2001:56A:739C:6D00:7C64:AE2F:5D54:DDA5 (talk) 05:39, 12 September 2016 (UTC)eek


 * I don't know if the figures have been rearranged, but looking at the top two in relativity of simultaneity: in the top one, we see three axes within a single light cone based on the central point.  The light cone is defined as lines of slope 1, i.e. it cuts each square diagonally on the graph.  The actual trajectories are within it and can vary.  In the second figure, we see apparent simultaneity change with frame, but the graph squares always stay on the light cone: in other words, the Lorentz contraction compensates for the time dilation to keep everything on the 45 degree line. Wnt (talk) 12:28, 14 September 2016 (UTC)

Protection against alpha and beta radiation emitters
Hi regulars,

I have a question that troubles me quite a bit. I don't want to go into too much details, but I regularly visit a decommissioned military facility that has now been made available for corporate use. This facility goes back to the 40's and some parts of the compound handled radium and other parts that are rumored to have been housing material exposed to the early atom and hydrogen bomb testing programs. I've also discovered that there is at least two fatalities in recent history both related to Leukemia. A survey over a couple of decades ago apparently ruled out gamma emitters.

I'm not entirely confident I can trust local monitoring authorities about the truth. So what I am asking is how could I potentially protect myself here in this situation. Additionally, are there any DIY tests I can carry out myself to pick up any potential alpha or beta emitters? I'm particularly scared about fine dust which is easily kicked up and floats around in the air.

Thanks, Kyle. 174.2.87.74 (talk) 22:57, 9 September 2016 (UTC)


 * We might be able to get info on the site if you tell us what it is. I mean lots of people go to e.g. Oak Ridge National Laboratory, and I don't think saying which facility it is would compromise your anonymity. But maybe there's something I'm missing. If you're concerned about dust, | dust masks are readily available. SemanticMantis (talk) 23:21, 9 September 2016 (UTC)


 * It's called Aston Down in the United Kingdom, I've visited a few of the hangers since March. I can't dig up a huge amount of info about all the buildings however. I do know that there are two that are notorious, however. Kyle. 174.2.87.74 (talk) 23:26, 9 September 2016 (UTC)


 * Alpha emitters will barely crack the skin, and beta emitters often will not get that deep and can be screened out with relatively weak barriers. The big catch is that if you eat any of them, they get to irradiate you from the inside and are at their most dangerous.  To assay for alpha emitters, you really need a scintillation counter.  Betas show up on a Geiger counter but depending on the isotope it may not be very sensitive.  Neither one really is checked very well by badge dosimeters, though betas would have more of a chance of being seen.  We have a lot of articles about radiation that you can go through.  But if there's one old little-used faucet in the basement that has tritium smeared on it that nobody ever cleaned, you could walk through the building top to bottom with a Geiger counter, take swabs off all the countertops and count them, and you'd still be none the wiser; then tomorrow you might twist it and take a drink out of your hand and exceed recommended radiation limits.  There's a reason why radiation gives people the creeps; yet it's probably not going to do anything most of the time. Wnt (talk) 23:41, 9 September 2016 (UTC)
 * Eat or inhale. As the original poster touched on, dust is a big problem in radioactively contaminated sites. This is why you see radiation workers suited up in NBC suits. A widespread misconception is that the suits are to "block radiation", but those suits aren't going to do anything to stop gamma radiation. Their purpose is to keep radioactive stuff off your skin and undergarments, and out of your lungs. --47.138.165.200 (talk) 04:09, 10 September 2016 (UTC)


 * There's really not much at Aston Down. It wasn't any sort of engineering plant, it was just an RAF station with a few radium dials on instruments. You'd get more trouble from an old clock factory.
 * You'll not detect anything by wandering around with a counter. Instead you'd need an air sampler and filter, then counting the filters afterwards. Or sweep up some dust.   Unless you find an untouched instrument workshop from 50 years ago though, there's very little about.   A much bigger hazard on Gloucestershire airfields would usually be beryllium oxide from early airborne radar. Andy Dingley (talk) 11:49, 10 September 2016 (UTC)
 * We do have an article on Aston Down, which mentions the contamination of the site (sourced to a local newspaper). Tevildo (talk) 15:47, 10 September 2016 (UTC)
 * According to this they stored radioactive waste from nuclear tests - one would hope that it was kept in well sealed containers. Our article also mentions arsenic, hydrocarbons and radium but that isn't supported by the reference given. Richerman    (talk) 21:27, 10 September 2016 (UTC)

Please identify this mushroom in my garden
Thanks! Gil_mo (talk) 23:09, 9 September 2016 (UTC)


 * I haven't used this site, but it looks slick. But as I expected, it *really* would like to see the underside of that mushroom - what the gills look like and how they are attached to the stipe. Wnt (talk) 23:31, 9 September 2016 (UTC)


 * Yup. More info needed. Perhaps Conocybe apala. --Tagishsimon (talk) 23:39, 9 September 2016 (UTC)


 * The location of the garden could also be a useful clue. Roger (Dodger67) (talk) 15:47, 10 September 2016 (UTC)
 * The photo contains information locating it to Israel. It's on the Commons description page. Wnt (talk) 20:10, 10 September 2016 (UTC)