Wikipedia:Reference desk/Archives/Science/2011 December 29

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December 29

ClF₃ vs. (CF₂)_n

Can chlorine trifluoride oxidize polytetrafluoroethylene? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 00:51, 29 December 2011 (UTC)

The fact that both are used in uranium hexafluoride processing would suggest no. Rmhermen (talk) 01:39, 29 December 2011 (UTC)

But PTFE contains carbon-carbon bonds, which ClF₃ can break apart. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:28, 29 December 2011 (UTC)

CDC says Teflon is non-reactive with ClF3: [www.cdc.gov/niosh/docs/81-123/pdfs/0117.pdf] Rmhermen (talk) 04:25, 29 December 2011 (UTC)

life

Well there are a lot of mind boggling questions about abiogenesis in my mind that I can't put it in words very accurately.But the one that I can say is the following: Is the simplest life form ever known to man irreducibly complex, according to current understanding of biology?And in what point could the structures be called life? Is there any scientific theory that states that life is a property of all matter(because I sometimes tend to think likewise!)?--Irrational number (talk) 13:11, 29 December 2011 (UTC)

You can find some good minimum definitions of life here: life. --Goodbye Galaxy (talk) 15:09, 29 December 2011 (UTC)

Some of these questions are tackled in "The origins of order" [1], or the more pop-sci version "At home in the universe" [2]. One of the key themes is that life-like structures are an expected, emergent property of complex systems. SemanticMantis (talk) 15:19, 29 December 2011 (UTC)

According to the current understanding of Biology, no life is irreducibly complex in the sense of evolution being unable to produce it, though that understanding includes the realisation that biologists may not yet had the time to work out the details of all claimed instances of irreducible complexity. {The poster formerly known as 87.81.2301.95} 90.193.78.56 (talk) 15:26, 29 December 2011 (UTC)

The first question is a bit too vague. "Irreducibly complex" is subjective to the human ability to replicate nature and is not synonymous with "impossible". We simply do not possess the technology required yet. Add to that the simple facts that Earth's conditions have changed drastically (ironically mostly as a result of the rise of life) and microscopic lifeforms almost always never leave recognizable fossils. So all life is basically irreducibly complex in terms of laboratory replication, but that does not automatically mean life is designed either (it's possible of course, but unlikely).

The definition of life is also subjective and adds to the problem of the first question. Life is currently defined on what life we can find and recognize and makes little or no concessions as to possible or existing lifeforms that do not meet the requirements. As such, the "simplest" lifeforms (Pelagibacter ubique for free-living organisms and Mycoplasma genitalium for organisms dependent on other lifeforms for survival) are defined not because they are the most primitive, but because they have the smallest genomes for anything that meets the most widely accepted definition of "life". However, they are obviously "devolved" (or more accurately, stripped down for maximum efficiency) descendants of more complex earlier lifeforms and thus might not even resemble the precursors of life.

Viruses may have also arisen similarly but are likewise generally not considered alive, as are organelles of possible endosymbiotic origins, etc. They are considered merely fragments of life. Hence the paradox that the earliest lifeforms would not actually be considered alive by today's definition, merely being chemicals that eventually gave rise to complex life by aggregation, endosymbiosis, horizontal gene transfer, assimilation, etc. with possibly widely different individual origins. Protobionts are examples of such "non-living" chemicals that may have given rise to life. And they have already been successfully synthesized in laboratory conditions mimicking probable early Earth environments.

The problem is not that the lifeforms considered to be the simplest are too complex, it's that our lower limit for the definition of life is too high. It's like trying to find the origins of the car but excluding beast/human-drawn wagons (and wheels) because they are not self-propelled. Currently the border between life and the inanimate wavers somewhere around the protobiont nanobacteria and viruses.

Lastly, I do not know of any such theories being seriously considered in science (maybe in metaphysics?) though I personally think attempts to restrict the definition of life is basically fruitless. It's a continuum, not an easily differentiated black-white distinction.-- Obsidi♠n Soul 15:27, 29 December 2011 (UTC)

Surely a major problem with this question on the Science Reference Desk is that it includes the term "irreducibly complex", a concept (almost?) exclusively used by creationists to prove science wrong. I don't think we should even be discussing this matter. Point out to the OP that irreducible complexity is a non-scientific concept, and move on. HiLo48 (talk) 22:46, 29 December 2011 (UTC)

Criticisms of science are off-topic at the science refdesk? Really? --Trovatore (talk) 22:54, 29 December 2011 (UTC)

Criticism based on fringe pseudo-science promoted by religiously driven nutcases? Yes. Off-topic. HiLo48 (talk) 04:44, 30 December 2011 (UTC)

People who want to understand the scientific explanations for the origins of life should be encouraged, especially if they're trying to grapple with misinformation they've gotten in the past. Shunning someone who is willing to engage sounds like the worst plan for advancing science. Rckrone (talk) 05:58, 30 December 2011 (UTC)

Some thoughts:

1) The idea of everything being alive is similar to the Gaia Hypothesis, which is more pseudoscience than true science.

2) Modern physics gives us the many worlds hypothesis, under which there may be an infinite number of universes. If true, then even the most unlikely events are bound to have occurred somewhere. And whoever evolves as a result may then look back at their evolution as an impossibility. StuRat (talk) 06:09, 30 December 2011 (UTC)

That particular interpretation of the many worlds hypothesis sounds more like the Anthropic principle than the actual many worlds hypothesis. --Jayron32 06:12, 30 December 2011 (UTC)

Okay, first, I'm sorry to use the word most scientists, and reasonable people, don't like.I'm an atheists myself, and according to what I know, the irreducible complexity is an argument (if it is at all) against evolution, not abiogenesis.but however, my question was "are there any species simpler than the first life form known to man?" which I kinda got a rough answer by reading the abiogenesis article, your answers and the links you provided.Thanks.-Irrational number (talk) 06:54, 30 December 2011 (UTC)

and the Idea of life being a property of matter came to my mind from what Stephen Hawking once said:"life is just matter that has been given enough time."...--Irrational number (talk) 07:41, 30 December 2011 (UTC)

For what it's worth, I call anything that can self-replicate "life". --Lgriot (talk) 09:12, 30 December 2011 (UTC)

That list would include many things we don't normally think of as alive, like many chemicals, crystals, computer viruses, and even stars. StuRat (talk) 16:37, 30 December 2011 (UTC)

Natural phenomena after Kim Jong-il's death

What is the scientific explanation behind the strange phenomena occurred after his death? --Pakocat (talk) 14:47, 29 December 2011 (UTC)

Propaganda. --Goodbye Galaxy (talk) 14:51, 29 December 2011 (UTC)

Perhaps exploiting coincidence. {The poster formerly know as 87.81.2301.95} 90.193.78.56 (talk) 15:31, 29 December 2011 (UTC)

= Propaganda and Confirmation bias.-- Obsidi♠n Soul 15:35, 29 December 2011 (UTC)

For example: (1) Comet Lovejoy surviving perihelion; and (2) the Green Bay Packers losing their first game of the season. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:49, 29 December 2011 (UTC)

Herd mentality, Groupthink, Deindividuation are a few more. Vespine (talk) 01:07, 30 December 2011 (UTC)

It is only appropriate to hear of such reports since miracles also occurred on the day of his birth, when a new bright star shone in the heavens, a double rainbow appeared, and birds sang his praise in human voices.[3] Christopher Hitchens was fond of saying that North Korea was the most religious country he had ever visited. -- ToE 11:49, 31 December 2011 (UTC)

Skin regeneration

If one was to say cut a hand by glass with a flap of skin hanging would the skin then regenerate over a few weeks/months without stitches? If so what would it be normal or damaged? And how long does it take to regenerate? A search on the net said a month for youngsters with fresher skin, but a doc recently told me that it would not regenerate normally without stitches to hold it in place.Lihaas (talk) 20:01, 29 December 2011 (UTC)

There is absolutely no way to answer this question. It totally depends on how deep the cut is, exactly where, what the cut is through, how much movement there is while it is healing, etc etc.. There's nothing really special about stitches, all they do is hold the wound closed tightly long enough for it to heal, but they do that extremely well, much better then just bandages. Vespine (talk) 22:01, 29 December 2011 (UTC)

a flap of lose skin on the ring finger iright hand depper than the skin itself. a little turmeric was used to clean the wound, and really burnt. after the skin that was deadened for the stitching was reactivated it burnt (lack of blood after it was released, i guess).

but what do you mean "how much movement"? in the sense that after the anaesthetic wore off there was a buroing sensation with a a sort of "heart beat" in the fingerLihaas (talk) 22:38, 29 December 2011 (UTC)

I just mean how much movement the area of the wound is subject to. The main thing stitches do is create a mechanical brace which closes the wound, applies pressure and prevents the edges of the wound from moving during the healing process. Vespine (talk) 00:57, 30 December 2011 (UTC)

And just to be sure, this is not an appropriate place to ask for medical advice, if you have any concern you need to go see a medical professional. Don't blame us if you lose a finger to infection. Vespine (talk) 01:03, 30 December 2011 (UTC)

Not for me, some doc was telling me about a case and i did some research on the internet for a topic i knew nothing about.Lihaas (talk) 10:41, 30 December 2011 (UTC)

Bedroom window

I have noticed that if I have my bedroom window open at night, to keep the bedroom cool and get fresh air, that I sleep much better. Is there more oxygen in cold air? Why does one sleep better with a open window at night? Dumb questions from a dumb blonde.--Christie the puppy lover (talk) 20:42, 29 December 2011 (UTC)

The article on Circadian rhythm might help you. Human evolution means we have become accustomed to warm days and cold nights and so our circadian rhythm has adapted to that. why do blondes covet the title of 'dumb'? Some of my best friends are redheads and many take the biscuit in this attribute. --Aspro (talk) 20:56, 29 December 2011 (UTC)

Ben Franklin already wrote about this: The Art of Procuring Pleasant Dreams. — Sebastian 03:50, 30 December 2011 (UTC)

The temperature won't much affect the oxygen content, but a very well sealed house can have less oxygen inside, due to breathing and combustion (gas stoves, etc.). There could also be an accumulation of toxins inside, like carbon dioxide, hydrogen sulfide, and maybe even some carbon monoxide (which might put you to sleep permanently). StuRat (talk) 04:28, 30 December 2011 (UTC)

Thanks gentlemen. That helps out a dumb blonde alot.--Christie the puppy lover (talk) 00:00, 31 December 2011 (UTC)

Gosh, we've be called gentleman. Must be due to that bottle of Braggi aftershave I was given at Christmas. --Aspro (talk) 00:07, 31 December 2011 (UTC)

Sugar Thermite?

I am curious if Aluminum would react with a sugar such as Glucose or Sucrose? Where the reaction removes Oxygen from the sugar and the products are a Carbon-Hydrgoen compound and Aluminum Oxide. Presuming the reaction even would occur. Similarly, could Calcium Oxide react with sugar to produce products of Calcium Carbonate and a Carbon-Hydrogen compound? I am more optimistic about the latter reaction, since if I was to combust the sugar with Oxygen first I would acquire water and Carbon Dioxide, which are used normally to create concrete from Calcium Oxide.Tartarean (talk) 21:16, 29 December 2011 (UTC)

I don't know whether or not this could be done, but I'm sure you'd need some kind of catalyst: I'm confident that I could leave a Pepsi can in a vat of white sugar without anything dangerous happening. Nyttend (talk) 00:37, 30 December 2011 (UTC)

I don't think it would happen, but not for the reasons Nyttend states. Thermite depends on finely powdered aluminum in order to work, you need a LOT of surface area. As far as a reaction of such finely powdered aluminum with sugar; I'm not so sure. Even if, thermodynaically, it should produce a product, it may not kinetically produce it at a rate to be considered proper "thermite". After all, rusting is technically a "combustion" reaction, at least in the sense that it describes a substance reacting with dioxygen. But no one would consider rusting to be anything like burning. Likewise, even if one were to replace the iron (iii) oxide normally present as the oxidizing agent in thermite with a carbon-based oxidizing agent, that wouldn't necessarily mean you'd get the spectacular thermite reaction. --Jayron32 00:55, 30 December 2011 (UTC)

More basically, can sugar be used as an oxidant in a flashy, spectacular manner, in the way that iron oxide is in a thermite reaction? I can't find any examples, but I bet it can, under the proper circumstances. Magnesium is well known to burn in a carbon dioxide atmosphere or a chunk of dry ice. I bet if you encased a strip of Magnesium in sugar crystals, lit it up, and then flushed the atmosphere with Argon, it would continue to burn. No way of knowing without trying it though. Granted, Magnesium has a somewhat higher reduction potential than Aluminum. I know a couple people who have access to the required materials and safety equipment. Maybe after they get off break I'll try to talk them into an experiment. Buddy431 (talk) 06:38, 30 December 2011 (UTC)

Sugar and sulfuric acid combine to make a fast-burning, gas-releasing mixture. Here's an explanation: The Dehydration of Sugar by Sulfuric Acid. Use caution: the reaction is very fast, very hot, releases a lot of steam - and I seem to recall it also produces some quantity of hydrogen sulfide gas, which can be toxic and explosive. Nonetheless, this sugar experiment is often performed in high school chemistry labs. Here's a video, Sugar Snake, showing the evolution into a oozing, charcoal-colored substance. I've performed this reaction and created a sugar snake that leaps up a lot faster - I may have had more concentrated acid than was used in the Youtube demo. (Comment: this is a dehydration, not a combustion, reaction).

I have also seen sugar used as a (messy) rocket fuel. In pure Oxygen atmospheres, nearly anything will serve as a fuel; and sugar does have a lot of energy per unit mass. I don't think I've ever seen a sugar-like substance used as the oxidizer. Nimur (talk) 16:31, 30 December 2011 (UTC)

Sure, sugar's used all the time as a fuel (reductant). Why do you consider it messy? Making Rocket candy has gotten down to almost a science in some amateur rocket circles. I've never heard of sugar as an oxidizer either, but I bet it can be done

So now that I'm actually awake I looked up some thermodynamic numbers. Using Red iron oxide and aluminum powder, the thermite reaction has a standard enthalpy of -425 kJ/mole Al. Using an idealized reaction of aluminum with Glucose, and giving a byproduct of 1-hexene (with enthalpy of formation taken from 1-Hexene (data page)), the standard enthalpy change is -541 kJ/mole Al, somewhat better than pure thermite. No, 1-hexene isn't likely to be the actual product in any significant amount, but it doesn't matter much: from a thermodynamic perspective, the reaction ought to take place.

However, I've also been thinking about the reaction conditions. The byproduct, rather than iron, is going to be light hydrocarbons. While the iron formed simply flows down to the bottom of a thermite reaction (being more dense), these light hydrocarbons are going to vaporize as they're formed, potentially throwing flaming material everywhere. There's a good chance that they in turn would burn with the oxygen in the atmosphere, potentially leading to a pretty big fire hazard, more so than a normal metal oxide thermite reaction. If someone does try it, please be careful. Buddy431 (talk) 20:32, 30 December 2011 (UTC)

As I mentioned above, thermodynamics is not the only factor in producing big flashy booms. Reaction kinetics are quite important as well, and determine the difference between a bang and a fizzle much more than thermodynamics will. --Jayron32 23:55, 30 December 2011 (UTC)

Bland question here on Ref Desk get deleted if there is any hint of them being medial but here is something that could be construed as aiding a would be terrorist. What are your priorities here???--Aspro (talk) 00:15, 31 December 2011 (UTC)

A 'would-be terrorist' who has a large supply of finely-powdered aluminium and sugar, but no access to anything more conventional in the way of explosives? Admittedly some 'would-be terrorists' have demonstrated a remarkable level of incompetence, but even so... AndyTheGrump (talk) 00:47, 31 December 2011 (UTC)

And like other people, thay may possess the ability to learn. Who would have thought... The chapati flour and bleach bomb. --Aspro (talk) 00:57, 31 December 2011 (UTC)

Ok then, because terrorists might use information from Wikipedia, we should shut it down? And BTW, I think that even terrorists have the sense not to believe everything they read in the Daily Mail ;-) AndyTheGrump (talk) 05:09, 31 December 2011 (UTC)

Great question. Thanks. The point I'm sarcastically making (all be it not very well) is that both clinicians and lawyers have succeeded in keeping their own discipline sacrosanct on Wikipedia. Why? To suggest meddling in their affairs is the most dangerous, is FUD in comparison the real world. Some of the advice regarding chemicals, engineering and other topics, make me glad that those posting the advice are not my next-door neighbors. So why on Wikipedia -that prides its self on neutrality- is this unexamined special respect, metered out on the subjects of law and medicine? Yet, if we question the Ref Desk posts such as this, it may help people to see this is a charade and an act of subtle but effective censorship. Can I take it also, that you have now tacitly admitted to actually having read a copy or two of the that wonderful edifier of the British hoi polloi entitled The Daily Mail? ;-) --Aspro (talk) 17:40, 31 December 2011 (UTC)

Personally, I see discouraging unqualified people from giving medical and legal advice an act of common sense. If you want to argue otherwise, I suggest you raise the matter in a more appropriate place - though dragging out the same old tired clichés about 'censorship' isn't likely to get you far. AndyTheGrump (talk) 17:47, 31 December 2011 (UTC)

This is the first time I've have brought up or heard mentioned this old tired cliché. It suggests to me some minds are fixed and petrified Telegraph readers.--Aspro (talk) 18:00, 31 December 2011 (UTC)