Wikipedia:Reference desk/Archives/Science/2012 January 3

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January 3

Unconfirmed discoveries elements

In Timeline of chemical elements discoveries, there are 4 elements that are unconfirmed. What is that mean? Thanks!Trongphu (talk) 00:53, 3 January 2012 (UTC)

And someone explain this statement to me too, "Of the 118 known elements, only the first 94 are known to occur naturally on Earth (88 in non-trace amounts"? What they mean by non-trace amounts? Thanks!Trongphu (talk) 00:58, 3 January 2012 (UTC)

Unconfirmed in this context means that the labs in question said, "we ran this experiment on our big machine, and we detected what seems like a radioactive signature which seems to be this new unknown element," but no other labs have duplicated this yet and the International Union of Pure and Applied Chemistry has not agreed that the discovery took place. It can be non-trivial to duplicate some of these experiments because they are often tuned to the specific properties of the specific particle accelerators they were originally performed in, so finding a way to adapt that to another machine can be tricky. This is why it took awhile for them to figure out that the original claim for the discovery of element 118 was fraudulent — it wasn't just a matter of saying, "oh, this doesn't work after all" — there was basically only one or two other facilities in the world that could replicate aspects of the experiment, but neither of them were perfectly identical, so it took awhile — about a year — to figure out that the problem was the original data, not the replication attempts. You can see, for example, with ununcotium, that the 2002 discovery report by the Russians was recently declared to not be correct.

A trace amount means, "this element is theoretically created by natural (Earth) processes, but we haven't seen it or it's extremely rare." An example of this is plutonium, which is sometimes created in uranium ores where spontaneous fission and reabsorption of neutrons occurs. It's on the order of a few parts per trillion — very rare, but technically there. The vast, vast majority of plutonium on Earth was created by artificial means (nuclear reactors and particle accelerators). --Mr.98 (talk) 01:44, 3 January 2012 (UTC)

But for all 4 of them, it has been more than 1 years and why is it still unconfirmed? 3 of them has been discovered like about 10 years ago. And this statement also confused me "In 2011, the IUPAC has evaluated the 2006 results of the Dubna-Livermore collaboration and concluded that they did not meet the criteria for discovery." So did we actually discover element Ununoctium yet?Trongphu (talk) 02:00, 3 January 2012 (UTC)

In each case it's likely a different reason as to why the delay and/or lack of recognition. The specifics are probably quite technical. It seems like element 118 has not been discovered yet. It's possible the table is not up to date, but we'd want someone more versed in the specifics to make the call on that. --Mr.98 (talk) 02:38, 3 January 2012 (UTC)

If you want, you can read the gory details of the report where IUPAC recognized 114 and 116 as having been discovered, and rejected the 118 claim (they have a section on criteria, which in turn refers to an earlier, 1992 report of guidelines). Buddy431 (talk) 03:00, 3 January 2012 (UTC)

It's not that Uuo hasn't been discovered, it's just that the evidence for this element is not strong enough (in the eyes of IUPAC) to merit recognition as of yet, especially since ²⁹⁴Uuo (the isotope they claimed to have discovered) does not decay to isotopes of lighter elements that were known before the synthesis of ²⁹⁴Uuo. It most probably has been discovered, as nobody seems to have questioned their claims. IUPAC states that "evidence in the cases of elements Z = 113, 115, and 118 have not met the criteria for discovery", and a connection to known isotopes is one of their criteria (although they say it only makes it more "troublesome", rather than "exclusive"). "Unconfirmed" probably means that no second group has verified their claim by reproducing the experiment yet. Double sharp (talk) 11:51, 3 January 2012 (UTC)

Best solution for IED (Improvised Explosive Device)

So I've been watching Deadliest Arms Race on National Geographic and after seeing how many soldiers, photo journalists, medics, etc. are injured if not killed by this relatively simply device that almost anyone with a pulse could build I'm convinced there has to be a somewhat equally effective and inexpensive solution we can muster up. More specifically, these devices for the most part are set off using a pressure plate to ignite them meaning a solider or hummvee or anything above the weight threshold triggers the device and boom. Would a viable solution be a solder or vehicle that was armed with a device that had an anchor or weight that could be launched anywhere from 50 to 200 meters and then retracted so that it would pass over the next 50 to 200 meters of terrain to trigger or detonate any IED's that a solider may have missed or one that would have been too destructive for an armored car? It would be similar to a grappling hook that could be launched just instead of a hook just a weight and retracted quick enough to prevent troops from being stationary for too long it could either be powered by an explosive, air pressure, or magnetically. Is this a viable solution? Have things like this been tried before and failed? Sorry for asking so many questions I'm just looking for someone with some military knowledge or a good answer! Thanks! — Preceding unsigned comment added by 76.108.156.117 (talk) 02:22, 3 January 2012 (UTC)

Doesn't sound viable to me:

1) It would slow them down dramatically, allowing enemy forces to gather and ambush them.

2) Using such a device would be exhausting (this doesn't apply to the vehicle launched version).

3) The insurgents would soon adapt and use other trigger mechanism, like cell phones and a spotter. StuRat (talk) 02:26, 3 January 2012 (UTC)

I don't know why you think that the fact that the weapon is simple means the countermeasures should be simple as well. Offensive capability and defensive capability are not symmetrical. In most cases offense is much easier than defense. Defensive measures are generally much more resource intensive and/or globally disruptive than offensive measures, because a true defense has to be able to guard against lots of possible attacks, while the offense generally has to get through one type of defense. (Consider how many resources it takes to prevent car bombings — day in, day out, when you don't know where the target is going to be — versus the resources it takes to implement them.)

As for your specific situation, it sounds pretty silly to me. Imagine if every car going down every crowded street was shooting a retractable anchor at every possible place that could hold an IED. It would be completely ridiculous. If there weren't IEDs, they'd probably be kicking trash heaps around every neighborhood, breaking things willy-nilly, generally being completely disruptive. If there were IEDs, they'd be setting off explosions. Neither are very viable even in a remote war zone, much less a city filled with civilians.

The simplest IED defense is having well-armored vehicles. Even that isn't that simple. --Mr.98 (talk) 02:43, 3 January 2012 (UTC)

(edit conflict with Mr. 98) In fact, roadside bombs increasingly have been triggered remotely, often by cell phone phones and similar devices [1]. The article I linked claims that about 90% of IEDs are found and disabled before they can hurt someone. Here's an interesting report from 2008 about the use of IEDs in Iraq. The wide availability of conventional munitions (capable of being turned into bombs), along with a "target rich environment" leads to a situation where IEDs are the leading cause of casualties, even if, individually, they are relatively ineffective and likely to be disarmed. Buddy431 (talk) 02:55, 3 January 2012 (UTC)

An IED is essentially an improvised land mine. Various land mine clearing techniques are called Demining, that article even has a photo of a soldier training a technique using a grappling hook. The problem as already stated is that this slows you down, you can only practically employ it in situations where you believe there is a very high risk of land mines and the thing with IEDs is that they can be placed in the places where they are NOT expected. Vespine (talk) 03:01, 3 January 2012 (UTC)

And speaking of which, of course our article even has a relevant section Improvised_explosive_device#Detection_and_disarmament. Vespine (talk) 03:04, 3 January 2012 (UTC)

What you're describing is essentially a loony-toons version of a Mine flail.

As others have said, it's not really possible to use them in every possible situation where a mine or ied could be used. (And, if their use in a particular region became commonplace, it wouldn't take a genius to stop using pressure-sensitive IEDs and switch over to something remote controlled, or timed, or whatever.) APL (talk) 04:26, 3 January 2012 (UTC)

A more effective solution is to have a robotic car lead the envoy. The car could be remotely controlled by someone in the second vehicle, or even from a command post thousands of kilometers away. If adding remote control is too hard, just use someone dispensable as the driver. --184.66.8.204 (talk) 05:52, 3 January 2012 (UTC)

Though the countermeasure to this is fairly obvious — trigger on random vehicles. Aside from the fact that robotic cars are neither cheap nor easy to use. --Mr.98 (talk) 12:48, 3 January 2012 (UTC)

U.S. television just finished a season of Bomb Patrol: Afghanistan where we got to see all sort of IED clearing machines and techniques including heavy rollers in front of the truck, large truck mounted metal detectors, a couple kinds of Nintendo-controller driven robots, etc. Cell phone controlled bombs were most common so we started putting radio jammers in each convoy then pressure plates became more common[2]. So then we added self-protection adaptive roller kit system (SPARKS) and mechanical claws to heavily armored trucks. 75.41.110.200 (talk) 16:15, 3 January 2012 (UTC)

Many persons in Iraq have been injured or killed by IEDs alongside the road,("roadside bombs") rather than directly in the road to be driven over. The flail would have to beat or the roller to smash down not only the pavement, but every object next to the road, such as parked cars, dead animals and trash cans. Bombs were commonly placed in the median strips of divided highways, and under bridges which convoys drive over or under. The proposed method would be useless in these cases. Huge bombs could also be placed in sewer or drain pipes or culverts or manholes under the road, and set off by wire, preventing detonation by flail or roller, and being relatively immune to electronic jamming. In the 19th and early 20th centuries, occupying armies resorted to Collective punishment (Not that I am recommending that course), to discourage attacks on convoys, rather than attempting to make every vehicle bullet proof and bomb proof. Robot or remote-piloted vehicles are rapidly getting more capable, as witnessed by the DARPA Grand Challenge (2007) and the Google driverless cars. Many deaths among the US and allied forces in Iraq were in attacks on supply convoys, which could in future occupations be unmanned vehicles, such as the remote piloted tracked vehicles made by Howe & Howe Tech, and watched from above by Unmanned aerial vehicles, [3], [4], which could attack persons planting bombs before a convoy rolls, or seen nearby with a celphone or pushbutton trying to trigger a blast when a convoy approaches. In Iraq, one big problem was that immense military stores of high explosive as well as bombs and warheads were left unguarded in the initial weeks of the occupation, or even years after the invasion, rather than being destroyed, either because US forces lack the manpower to guard the ammo dumps, or because US forces wanted to search through them for the supposed weapons of mass destruction which were the principal justification for the invasion. See Al Qa'qaa high explosives controversy, for instance. When combat operation ended, early after the invasion, there were 600,000 to 1 million tons of munitions left in Iraq government warehouses and in munition stockpiles averaging 40 tons, throughout the country, possibly with the specific intent of equipping insurgents for a protracted IED assault on convoys and buildings. In some cases, the metal panels of the warehouse were removed by scavengers, leaving piles of bombs visible, Eventually the bombs also disappeared, to be used for IEDs. A helicopter pilot lamented that one rocket would have gotten rid of the whole pile of bombs. In addition to these explosives negligently provided to the insurgents, supplies of high explosives may have been smuggled in from other countries opposed to the allied occupation. If the partisans had to make explosives out of raw ingredients, (a little home made gunpowder, or some other McGyver bomb) the lethal effects would have been far less than just setting off a large 122 mm artillery shell, as has been the common practice with Iraq IEDs, rather than some home-made Swiss Family Robinson cocoanut bomb with improvised black powder. Edison (talk) 16:31, 3 January 2012 (UTC)

You might find the following article interesting old chap. It's from the Mirror which is a bit of a rag but seems plausible. It's a report on our good old boys in uniform mounting leaf blowers on their remote controlled jobbies to blow debris and dirt away to expose those beastly bombs - see [5]. Tip-top idea if I do say so myself, rah! Quintessential British Gentleman (talk) 19:27, 3 January 2012 (UTC)

I've seen video documentaries showing some rather elaborate anti-IED vehicles, but the best solution is clearly (a) don't give people good reasons to want to blow you up, followed by (b) don't drop vast amounts of explosive on them that include a high percentage of duds that they can scavenge for explosives. Wnt (talk) 09:10, 4 January 2012 (UTC)

The American army can easily defend itself against IEDs by not invading other countries. The number of American soldiers killed by IEDs in their own country is quite low. IEDs in countries like Afghanistan are only deadly within a rather close proximity. I believe this method is a cheap and effective way of saving lifes. Von Restorff (talk) 13:50, 4 January 2012 (UTC)

Attacks have occurred in the US, as well as in nations the US didn't invade, just in other forms. Also note that they took place before the invasions of Afghanistan and Iraq. You might have a point on Iraq, but the idea that Americans would be safer had the US left the Taliban in Afghanistan to protect Al Qaeda there (as it planned future attacks) is ludicrous. StuRat (talk) 19:57, 6 January 2012 (UTC)

It is rather important to carefully read what I wrote before replying to it. Was I talking about "Americans" in general or was I talking about the American army and the American soldiers? The Wikipedia article about the September 11 attack says: Nearly all of the victims were civilians; 55 military personnel were among those killed at the Pentagon. I have not yet found a reliable source about number of military personnel and the number of civilians killed in the Oklahoma City bombing. Von Restorff (talk) 01:02, 7 January 2012 (UTC)

Wait until they figure out how to nuke.. hmmm NO ;) However Iraq seems not to achieved much else than an overthrown dictator. Electron9 (talk) 20:23, 6 January 2012 (UTC)

An idea is to use molecular sniffers that fly along the road on a "search-and-destroy" mission. Electron9 (talk) 20:23, 6 January 2012 (UTC)

I got this idea from Mockingjay, which is probably not the most reliable of sources, but what about just blasting 'em with machine-gun fire till they explode? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 03:45, 7 January 2012 (UTC)

The hard part is finding them before they explode. Blowing them up is relatively easy. Von Restorff (talk) 04:56, 7 January 2012 (UTC)

How about saturating the ground in an area with machine-gun fire to detonate any mines? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 05:12, 7 January 2012 (UTC)

The most effective way of dealing with IEDs is to track every person in the city all the time, then just run the tape backwards from the explosion and go pay the plantee a nighttime visit. I.e. Gorgon Stare. I can't wait for this Pentagon funded development to pay off in America to catch all those jaywalkers, skinny dippers and public urinators. Hcobb (talk) 06:24, 7 January 2012 (UTC)

At least with standard visual cameras this would be quite readily defeated by those intending an attack. Even if you resort to implanted microchips or (hypothetically) terahertz DNA sequencing, no punishment in the world will deter someone if he's already sampling his 72 virgins when you arrive. Wnt (talk) 19:38, 7 January 2012 (UTC)

Maybe ground penetrating radar in front can help? I still think one has to locate the device. Just blasting around isn't efficient. Electron9 (talk) 09:45, 7 January 2012 (UTC)

Use of Inhaler for Asthma

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page.

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis or prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page. --~~~~

I'm first aider, often working in remote locations, possibly several hours from medical support. Knowledge of the use of asthma inhalers is part of my skill set. Obviously I'm not a medico. But we are allowed to beg, borrow and steal, then encourage the use of inhalers when they are likely to help. They are highly unlikely to do any harm. When I saw the heading, I thought this item could add something useful to my first aid knowledge. Sadly, it's been deemed a request for medical advice. Has the difference between first aid advice and medical advice ever been discussed here? HiLo48 (talk) 21:55, 3 January 2012 (UTC)

Clock and sundial comparison in General Relativity

Just thought of this. Go on, shoot it down in flames. Clocks are shown to run slower at the base of skyscrapers compared to those on the top floor. (This prediction of Einstein's General Relativity has been empirically confirmed.) Now imagine two sundails on the ground and top floors. Will the one at the base indicate a time slower than the one higher up? If so, how would it work? And if not, would not this form of time measurement be impervious to the constraints of GE, and thus lead to impossible results? And in any case, if you had two sundails positioned alongside two atomic clocks on these floors, would you be able to measure the differences between the way they are counting time? Myles325a (talk) 07:31, 3 January 2012 (UTC)

The two sundials will give the same time, because the sun is in the same position. It doesn't seem to say anything about GR, so I don't see what would be impossible about the results. You couldn't measure any difference in the time available for your study, but over millions (?) of years you might be able to see that the sundial is gaining time, so to speak. IBE (talk) 09:01, 3 January 2012 (UTC)

If nothing else, the sundial at the bottom would lag the one at the top slightly - by an amount equally to height_of_building / speed_of_light. Also, because of the different locations, most of the time the angles between sun, gnomon and dial would differ slightly, so they would show slight different times. I don't have the time or inclination to work out how the time difference in each case compares to the time difference due to GR. Mitch Ames (talk) 10:13, 3 January 2012 (UTC)

There is actually no speed-of-light lag. The shadow moves on the sundial because of rotation of the Earth, and lower elevations don't lag behind higher elevations in the rotation. -- BenRG (talk) 22:21, 3 January 2012 (UTC)

But the core fact is that time passes slower at the bottom of the skyscraper than at the top. A sundial does not measure time, it measures the position of the sun. Since time is passing slower at the bottom, the solar day is shorter (in measured time, e.g. seconds) than at the top. Our units of time have historically been defined via observed celestial configurations (a day is the time between two sunsets/sunrises/solar noons, a month is the time between two full moons, a year is the time between two spring equinoxes...). All of these are not really units of time proper, since they vary quite a lot even for an observer at a given point on Earth, much more for different observers. We are still used to this historical accident, and have modelled it in our modern system of time keeping (to different approximations - months are too long, leap years are longer than other years, we use leap seconds to synchronise solar time and atomic time...). But this does not, of course, affect considerations of time in a cosmological context. --Stephan Schulz (talk) 10:30, 3 January 2012 (UTC)

Stephan Schulz's answer is correct, but I want to point out that essentially all of the time standards that we use in practice (UTC, TAI, "local" times) are more of the sundial type, i.e., they advance in lockstep everywhere on Earth and as a result don't exactly agree with proper time. A proper second is 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of a caesium 133 atom that's moving with you (see second), but a UTC second might be slightly more or fewer periods than that, depending on where you are and how fast you're going. This is really about convenience, not historical accident, since the main point of timekeeping is to synchronize things that aren't always following the same worldline. -- BenRG (talk) 22:21, 3 January 2012 (UTC)

In other words, we're going by not just the Greenwich latitude but also the Greenwich height, adopting a universal unit of time which is defined as time in one particular place. I think. Second mentions two laboratories working out the number of vibrations of cesium atoms in a second, but is that a second as measured at sea level or some other height? (And by GR is the time dilation the same at sea level at any latitude...?) And can we tell the difference? I ought to work this out myself but somehow I'm not getting my blood up right now. Wnt (talk) 09:04, 4 January 2012 (UTC)

You must distinguish between the time we use for most things, and "proper" time. For proper time, a second is always defined via the Cesium atom's hyperfine ground states. That means that a second for one observer is different than a second for a different observer. Time is not absolute - in fact, even order of events is not absolute. That is the "relativity" in Theory of Relativity, and its the thing that most people find even harder to grasp than the equations. As Ben said above, on Earth we are nearly always more interested in synchronization of our lives, not in real time keeping. You want to be at the train station at the same time as the train, you want to meet with your date at a restaurant (and boy, does time get dilated if one of you is late...). Since the differences in time on Earth are so minuscule, we can use local time for synchronization - local time between any two people on Earth is close enough that even the most discerning date will not walk out because of that difference. And, with GPS, NTP and radio clocks, we seem to be moving towards explicit synchronization again. Yes, time dilation at different latitudes is different because of the different speeds of the surface due to the rotation of the Earth. --Stephan Schulz (talk) 09:47, 4 January 2012 (UTC)

Thanks for answering on that last point, but have you taken everything into consideration? At lower latitudes the Earth moves faster, but sea level is higher. The gravitational potential energy is the same. But maybe the gravity itself at that height can still vary, because the gravitational potential is the sum of gravity going all the way up? Although the Gravitational time dilation article mentions gravitational potential, I think it's really just the plain acceleration felt at a spot rather than some more sophisticated number? So I'm thinking it might vary by some exceedingly small amount, but not by as much as you're saying - alas, I don't know what I'm talking about. ;) Wnt (talk) 17:08, 4 January 2012 (UTC)

Biological assignment

please help me to title of an assignment in which the table content are 1.human male reproductive system 2.human female reproductive system 3.fertility 4.menstruation 5.pregnancy 6.parturition 7.lactation. 8.family planning .Rikisupriyo (talk) 09:42, 3 January 2012 (UTC)

I have taken the liberty of providing your question with a header, so it's not confused with the previous question. Is there nothing in what you were given to do that may provide an answer? Grandiose (me, talk, contribs) 09:58, 3 January 2012 (UTC)

"Essay on human reproduction" --Lgriot (talk) 10:44, 3 January 2012 (UTC)

That is close to the current layout of our Human reproduction article. 75.41.110.200 (talk) 16:02, 3 January 2012 (UTC)

How about, "Human Reproduction: Neither Birds nor Bees." --Mr.98 (talk) 16:12, 3 January 2012 (UTC)

Actually, he could get the same kind of info for most any mammal. Except maybe for item 8 (family planning) or the omitted item 9 (divorce court and child custody) or 10 (STD's). ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:33, 4 January 2012 (UTC)

The user Jiminy Cricket who usually chimes in at the juncture to inform OP that WP never never issues medical information or helps out with homework is in in insect hospital have the poo removed from his head, so let me just skuttle in and tell you what he would have: "Bzzzz bzzzz...Wp is not a forum to obtain medical info, and how will you become a Rhodes Scholar and get a Nobel Prize if you don't DO YOUR OWN FREAKING RESEARCH!!!????

There...(wags finger) Myles325a (talk) 04:56, 4 January 2012 (UTC)

Directing readers to articles is a normal approach, so they can do their own homework. Asking how reproduction works in mammals is not asking for medical advice, it's simple biology. ←Baseball Bugs ^{What's up, Doc?} carrots→ 08:23, 4 January 2012 (UTC)

Nickel content in Rhodium

I have read that rhodium is linked to nickel ore and that's its use in jewelry is to add and long-lasting, durable shine. I have two certified gemologists going head to head, one insisting there are elements of nickel in rhodium, the other saying that's absolutely untrue. I'm stuck squarely in the middle, with a nickel allergy that makes me lean toward the first gemologist's opinion since I've had to get rid of some fairly pricey pieces of jewelry and am bearing the scars to prove it, besides which there were periods at the height of the allergic rashes during which I could not get a good table at my favorite restaurant, but the second guy is widely held to be the city's ranking expert. He told me I was stupid, which does tend to irritate me a bit, a character flow to which I freely admit, but I'm only interested in facts so that I might purchase jewelry from a well-informed position.Haramel (talk) 10:13, 3 January 2012 (UTC) <Wikipedia>

First, with regard to rashes, we cannot give any medical advice. Second, take a look at our articles Rhodium, which says it is an element. Rhodium can be chemically refined to a pure element, which would not contain nickel, but one metal may be alloyed with another, in which case nickel, gold, or other metals could be present. The rhodium article says it is rarely made into jewelry as a pure metal because of its high melting point and because it is low in ductility. The article Plating mentions the common practice of flashing sterling silver with a thin plated layer of rhodium to prevent the silver from tarnishing. (It's hard to understand how the item would look like silver if all you see is the layer of rhodium.Maybe "shiny silver"="shiny rhodium.") The plating article says that rhodium-flashed silver often has a layer of nickel over the silver and under the rhodium. In such a case, a scratch or flaw in the rhodium flashing or wear through of the rhodium plating could allow contact with the nickel layer. Is your "rhodium jewelry" solid pure rhodium, or is it something plated with rhodium? This site says that pure rhodium rings are likely to break, and that the metal costs many times more than gold, but one poster says he has made a few rhodium rings, or rings made of rhodium alloyed with platinum (which is cheaper than rhodium). This site says that white gold, silver and platinum are often plated with a few microns of rhodium to make the appearance whiter and to provide resistance to scratches, but that the plating can wear through in 1 to 5 years. Replating is said to be a reasonably priced option. Edison (talk) 16:05, 3 January 2012 (UTC)

This isn't my expertise, but according to the article rhodium is often isolated from nickel ore, so if rhodium is not perfectly pure it could have nickel in it. According to carat "fine" 24 carat gold is 99.9% pure; I don't know what the standards are for rhodium or what kind of rhodium you were sold, but clearly you might be interested in the standard used and preferably the original lot assay of the metal used. Additionally, there is a "adimethylglyoxime spot test" to check specific items for nickel. Also I'm seeing Google hits for rhodium being used to plate nickel containing jewelry like white gold, and the plating wears through releasing the nickel unless repeatedly reapplied; supposedly the plating can be good enough to protect people with nickel allergies ([6]). The social element of this perplexes me the most - a restaurant would seriously deny someone a good table because of an allergic rash? Isn't that illegal, not to mention just plain wrong? Wnt (talk) 16:51, 4 January 2012 (UTC)

De-miting a snake and its tank

My ball python just began to shed (verb) this morning, so I peeled off the rest of the shed (noun) under warm water with softsoap in the sink and I can't see any dark spots under its ventral scales, which suggests that I got him just at the right time to de-mite him. For the tank, I have the coconut bark bedding, which I look at from time to time and see that there are mites walking all over the place -- I scooped up a bunch of it, put it in a 9x13 aluminum pan and have it in the oven at 350° and will leave it there for about 15 minutes -- will that suffice to kill the mites and eggs living in the bedding? And then when there's no bedding left, I scrub the walls with bleach water? Does this sound like it will work, or once a snake is infested, it can never be clean? Thanx! DRosenbach ^{(Talk | Contribs)} 15:51, 3 January 2012 (UTC)

Have you tried asking your veterinarian/herpetologist? Someone who deals with snakes on a regular basis may be able to help you with this problem. --Jayron32 16:00, 3 January 2012 (UTC)

I thought someone who had a snake would be able to answer appropriately. Thanx! DRosenbach ^{(Talk | Contribs)} 16:33, 3 January 2012 (UTC)

“mites walking all over the place” -just a thought. Slow changes often go noticed. Could this vivarium have become too humid (thus encouraging mites)? I say this because I have found cheap domestic type hygrometers to be as much as 10% out in the 'normal' range. At the upper level for ball pythons this might be significant in causing the bedding to get moist.--Aspro (talk) 18:32, 3 January 2012 (UTC)

Disclaimer: I am not an expert, ask your local vet. Replace the bedding, do not clean and reuse it. Clean the vivarium (BUT NOT THE SNAKE!) with something like Ardap. The snake itself can be cleaned with something like Callington Mite Spray or ZooMed Mite Off. Drowning the mites on the snakes body is also an option in some cases. Von Restorff (talk) 14:22, 4 January 2012 (UTC)

Think by now the OP will have discovered that Google is his friend and gotten a lot of centred advice from like-minded herpetophiliacs. There is loads about this. Don't know about you Von Restorff but ever since this question was posted I've had the uncontrollable urge to itch myself. Feels like a bad case of formication coming on. Must wonder down to the garden shed, to see if there is any of that DDT powder left.--Aspro (talk) 14:58, 4 January 2012 (UTC)

I know another Aspro; a beautiful white cat with a green and a yellow eye owned by a friend of mine! Note to self: must wash hands after petting Aspro. Von Restorff (talk) 15:06, 4 January 2012 (UTC)

Caterpillar identification

Resolved

This video was made about a week ago in Israel -- can anyone help me identify the species? DRosenbach ^{(Talk | Contribs)} 17:10, 3 January 2012 (UTC)

Looks very much like a tomato hornworm, down to "eight V-shaped markings". Though it's native to North America, I think it is often an introduced pest where Solanaceae are cultivated. Anyone have a link describing the introduced range? SemanticMantis (talk) 17:21, 3 January 2012 (UTC)

Thanks! DRosenbach ^{(Talk | Contribs)} 21:42, 3 January 2012 (UTC)

Quick question...

How much can rhino beetles weigh at the most? (I didn't see anything on it in the article). Heck froze over (talk) 19:10, 3 January 2012 (UTC)

National Geographic says scarab beetles (of which the Rhinoceros Beetle is a type) can weigh up to 3.5oz/100g - one would assume that these big bugs are at the higher end of that range old boy! See [7]. Quintessential British Gentleman (talk) 21:45, 3 January 2012 (UTC)

Distance that an electric current will arc

Is there an equation that relates the distance an electric current can arc through air or another medium between two nodes based on their impedence, the voltage and/or other factors? Thanks, 78.144.251.167 (talk) 20:50, 3 January 2012 (UTC)

I don't know the answer, but the distance only affects the arcing probability which decreases with increasing distance. So, you should expect a statistical answer. Plasmic Physics (talk) 22:23, 3 January 2012 (UTC)

Electric spark mentions qualitatively how sparks form, it depends on the Dielectric strength of the air through which the arc is traversing, the relative voltage drop between the ends of the arc, etc. --Jayron32 22:30, 3 January 2012 (UTC)

The article High voltage says that in dry air,at standard temperature and pressure, the breakdown voltage between spherical electrodes is about 33 kilovolts per centimeter of separaation between the electrodes. This statement is defective in not specifying the diameter of the spherical electrodes. The breakdown for smaller electrodes or points will be less than for large spherical electrodes. Once a power arc occurs, there will be a typical voltage drop per distance. "Electrical power distribution handbook," (2004) by Short (how appropriate a name), page 344, says the voltage across an arc is 10 to 16 volts per centimeter, across a current range of 100 to 80,000 amperes. The power (and heat, and explosive force) from a power arc is amazingly large. That book states a 3 inch arc carrying 10,000 amperes dissipates a megawatt. Edison (talk) 23:30, 3 January 2012 (UTC)

Can we lose our soul?

I mean, could we lose, after some kind of brain damage, this feeling of self, but still be able to process information, in a rather automatic way? 88.8.76.174 (talk) 23:23, 3 January 2012 (UTC)

Sure. It's called the British Parliament. :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:56, 3 January 2012 (UTC)

On a more serious note. Dissociative disorder. Maybe also Lobotomy. Also, I expect you are just using the term figuratively, but I don't think any scientist would seriously call a mental disorder "losing your soul". Vespine (talk) 00:38, 4 January 2012 (UTC)

The notion of an incorporeal "soul" is a religious and philosophical concept, not a scientific one. See Cartesian duality for more on that philosophical topic. "Feeling of self", however, is a psychological topic, so that would fall within the realm of science. See Psychology of self. For a couple articles pertaining to the loss of sense of self, see Depersonalization and Depersonalization disorder, the latter of which is one kind of dissociative disorder. Red Act (talk) 02:14, 4 January 2012 (UTC)

See also Cotard delusion. Ariel. (talk) 10:26, 4 January 2012 (UTC)

Conservation of Momentum and Energy

Suppose there is a swinging pendulum with a negligible mass of string and no air resistance. It is released from a height and is allowed to swing. Since there is no friction, it will return to the same height after each swing. In this case, am I correct in assuming that total mechanical energy (PE + KE) is conserved, but momentum is not conserved? If so, what does being conserved mean in this case? Does it mean that it must have the same value at every point along the swing in order to be considered conserved? Since the momentum is always changing values, but will always return to the same value at the end of each swing cycle, is it still considered "not conserved?"

Lastly, is it also true that Kinetic Energy is not conserved? But total mechanical energy is?

Thanks, Acceptable (talk) 23:56, 3 January 2012 (UTC)

Momentum is conserved in a closed system. In this case, the pendulum is exerting a force on the Earth through the point where the string is anchored. When the pendulum is going left, the Earth is going right (with much smaller velocity).

It's true that kinetic energy is not conserved. Energy can change types. Rckrone (talk) 00:16, 4 January 2012 (UTC)

Are you thinking of Conservation of linear momentum? Nothing states momentum needs to be conserved when external forces, like gravity, act on an object. At the end of each swing cycle, the pendulum's momentum will be 0 and I believe you are correct that the total mechanical energy will be conserved, that's just another way of saying Conservation of energy. Vespine (talk) 00:19, 4 January 2012 (UTC)

"External" is a matter of definition. He is saying that if you include the Earth in the system, momentum is conserved (because then gravity is not an external force).--Srleffler (talk) 06:57, 7 January 2012 (UTC)

Rckrone: Note that the pendulum also exerts force on the Earth through gravity. This is important. The Earth's change in velocity due to gravitational force form the pendulum is negligible, but because the Earth is so massive, its change in momentum is significant.--Srleffler (talk) 06:57, 7 January 2012 (UTC)