Wikipedia:Reference desk/Archives/Science/2011 September 5

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September 5

a fly inside a moving car

whenever im inside a moving car and i see a fly, i always wonder why can it fly in the same manner as when the car is not moving.

They're able to fly inside a moving car for the same reasons that you're able to move around in the car. Assuming the windows are up, the air in the car is not blowing by at 60 mph. It's not the speed of the car that matters, it's their speed relative to the air immediately surrounding them that makes the difference. Dismas|^(talk) 00:16, 5 September 2011 (UTC)

But dont they need to move as fast as the car? — Preceding unsigned comment added by 203.112.82.1 (talk) 00:31, 5 September 2011 (UTC)

They already are... --Jayron32 00:31, 5 September 2011 (UTC)

This is true at a constant speed, but what happens if you accelerate or brake? I think that the the fly won't notice the change in 'g' that much, it will turn to keep itself oriented 'top up' - or will it? How does a fly sense which way is 'down'? AndyTheGrump (talk) 00:34, 5 September 2011 (UTC)

(EC) See principle of relativity and Galilean invariance. Red Act (talk) 00:37, 5 September 2011 (UTC)

im sorry to ask, what do you mean they already are? — Preceding unsigned comment added by 203.112.82.1 (talk) 00:40, 5 September 2011 (UTC)

If the fly is in the car, next to you, while you, the car, and the air are all moving 60 miles per hour relative to the road, the fly doesn't need to do anything special to keep up. If you slam on the brakes, you (and the air, and the fly) will continue to try to move forward at 60 miles per hour; you will be pressed into your seatbelt; the fly will likely slam into the windshield. It does not require any effort or force to maintain a constant speed, see inertia. --Jayron32 01:04, 5 September 2011 (UTC)

That's why I never wear a seatbelt -- for fear that I won't be able to breathe if I slam on the breaks and am held back by the seatbelt while all the air bunches up against the windshield. -- 110.49.240.219 (talk) 12:50, 5 September 2011 (UTC)

Another way to look at it: "Just like the seat is pushing you along at 60 mph, the air is pushing the fly along at that speed". StuRat (talk) 02:59, 5 September 2011 (UTC)

The problem with this way to look at it is that it is completely wrong. Nothing is pushing anything along inside the car. Everything is just moving side by side at the same speed. Dauto (talk) 03:20, 5 September 2011 (UTC)

During acceleration the seat and air are definitely pushing you and the fly along. StuRat (talk) 05:25, 5 September 2011 (UTC)

Yes, during acceleration, but not at constant speed. The air cannot do much pushing unless the fly flaps its wings, but then the fly is in aerodynamic control and is unlikely to slam into anything. It can easily cope with a sudden change in the magnitude and direction of apparent gravity as the car accelerates or brakes. Of course, once you open a window, the turbulent airflow is likely to confuse the fly and might cause it to be swept out of the car. Dbfirs 06:19, 5 September 2011 (UTC)

Put it this way: Suppose you have a pneumatic tube with a huge blower at one end, and a fly is loose in it. You turn up the fan to blow 60mph. How is the fly going to move? Yep, it's going to be blown down that tube at pretty close to 60mph whether it likes it or not. And that tube isn't even moving at 60 mph, just the air in it. The air in your car is moving at the same speed as the air in that tube, and the fly is in the middle of it. Wnt (talk) 18:40, 5 September 2011 (UTC)

True, but once the fly reaches 60mph, the air doesn't need to do any pushing because the fly just obeys Newton's first law. Dbfirs 18:43, 6 September 2011 (UTC)

Only so long as the car continues straight, and level, at constant speed. Not a good idea, as cops have this silly requirement about stopping at lights and such, and never turning or slowing does tend to leave one's car imbedded in the side of a random house somewhere. :-) StuRat (talk) 04:41, 8 September 2011 (UTC)

Good point! (though my last reply was to the wind-tunnel situation) Perhaps a better answer is that flies are capable of much higher accelerations (and decelerations) than cars (try catching a fly to observe this), so they cope with the comparatively small forces needed to maintain their position relative to the car and probably hardly notice that they need extra wing-flaps to adjust (I don't know how flies think, but I suspect that they just react instinctively.) Static air doesn't do much pushing, but a fly in the air is largely in control of the airflows needed to provide buoyancy and any accelerations required to match the car's motion. In a similar way, when I used to stand on a trailer moving over rough ground, I learnt to adjust to the sudden accelerations needed to maintain my position on the trailer. Sailors on a rough sea similarly cope with accelerating themselves to match the ship's motion (though a landlubber might easily be slammed into bulkhead). Dbfirs 08:42, 8 September 2011 (UTC)

Physiotherapy

Can physiotherapists use the prefix "Dr." before their name? --DinoXYZ (talk) 00:36, 5 September 2011 (UTC)

A physical therapist who has earned a Doctor of Physical Therapy (or equivalent) could use the title "Dr.", but not all physical therapists have doctorates. In addition, the requirements for physical therapy education and licensing vary greatly from country to country. Dragons flight (talk) 00:46, 5 September 2011 (UTC)

Then again, they might have a Ph.D. in comparative literature.... --Trovatore (talk) 03:25, 5 September 2011 (UTC)

The response above applies, I think, to the USA. Here in the UK I don't believe physiotherapists qualify to a 'doctorate' level. This does not of course imply that they are any less able as practitioners. Richard Avery (talk) 07:09, 5 September 2011 (UTC)

According to Doctor of Physical Therapy#United Kingdom, the degree does exist in the UK.

I am somewhat disturbed that the plan is apparently to require all physical therapists to have the degree by 2020. I have no problem with them getting the degree if they want to, but I frankly doubt that that level of study is really necessary to provide quality care. This looks to me like another attempt to restrict supply and drive up prices, part of a continuing trend that started (if not before) with the elimination of the no-residency-needed general practitioner of medicine. --Trovatore (talk) 07:15, 5 September 2011 (UTC)

Doctors (as in physicians) tend not to have doctorates either, but they are still addressed as "Dr. X". In the UK, there are no laws on who can use the title "Dr." (although there are laws about misleading people into thinking you hold qualifications or licenses to practice that you don't really hold). It tends to be a matter of convention within a particular profession. --Tango (talk) 11:31, 5 September 2011 (UTC)

No laws on who can use the title "Dr."? Do you mean in general or just regarding physicians?Quest09 (talk) 13:39, 5 September 2011 (UTC)

I think that's true in general in both the US and the UK, though I'm not sure for either one. I seem to recall hearing that in Germany it was illegal to call yourself "Dr." unless you have one of a set of recognized degrees (which apparently do not include a US-granted Ph.D., unless you make some special effort to have it vetted). But that's just not really in the common law tradition. --Trovatore (talk) 19:13, 5 September 2011 (UTC)

In the UK there was the case of Gillian McKeith, who had a PhD in Holistic Nutrition from the American Holistic College of Nutrition, but had to drop the Dr. from her company's advertising following a complaint. So, in the UK it's not entirely a sure route to prestige to put a Dr. before your name. Quest09 (talk) 22:01, 5 September 2011 (UTC)

I'm also curious about UK doctors not holding doctorates. Of course I don't necessarily consider the MD a real doctorate, but that's neither here nor there. "Real" or not, US medical doctors have to put in seven years after the Bachelor's degree before they can practice, that is eleven years since starting university, or sometimes much more depending on specialty.

I tend to see that as a conspiracy in restraint of trade; I'm not convinced that I really gain all that much from the fact that my primary care physician has gone through all that, compared with how much I'm (usually indirectly) paying for it. Do UK medical doctors have to do the same? --Trovatore (talk) 19:19, 5 September 2011 (UTC)

You can see the modern training route for British doctors here. You're looking at a minimum of 9 years to become a GP. DuncanHill (talk) 09:16, 7 September 2011 (UTC)

Implications of a Perpetual Motion Device

A favorite passtime of cranks seems to be perpetual motion, but what would the actual effects on our society as a whole be if an overunity device were created (Obviously, this is a purely hypothetical question, so please humour me). It would solve the energy crisis, but would it have any unexpected effects on the economy or everyday life? Rabuve (talk) 00:56, 5 September 2011 (UTC)

You seem to be seriously discounting the effects that "solving the energy crisis" would have on the economy and everyday life. If a perpetual motion device can provide power, then you would be able to eliminate several industries and put millions of people out of work. Dismas|^(talk) 00:59, 5 September 2011 (UTC)

(edit conflict) This is actually a serious topic of thought among economists, though not the perpetual motion problem, rather how a Post scarcity economy would work. It is a matter of some consternation; like many things not many economists agree on what it would mean, but many do agree it poses real problems for society. (post EC comment) As Dismas points out, that problem can be extended to many issues: When things stop being scarce, they drop in value. If something is so abundant that it is worthless; how does an economy deal with that? --Jayron32 01:01, 5 September 2011 (UTC)

It would be a infinite source of energy which would be a game changer as far as how society is organized. Dauto (talk) 01:03, 5 September 2011 (UTC)

I know that solving the energy crisis would have huge implications, but what I am asking is what those implications would be. — Preceding unsigned comment added by Rabuve (talk • contribs) 01:45, 5 September 2011 (UTC)

Indeed. What you should do is find economists who work in the field of Post scarcity economics. The wikipedia article has some ideas you can follow, and there's some links to economists who work in the field there as well. That is going to be your best shot at finding information to answer your question. --Jayron32 01:47, 5 September 2011 (UTC)

It's completely unnecessary to invoke perpetual motion to imagine a world with abundant "nearly free" energy. Regardless of how "free" the actual energy is, there would still be an infrastructure to support, collect, distribute and maintain it. But obviously yes, it would have a great impact on global power structure, economics and society, I don't think anyone can do much more then speculate. My personal suspicion is that the surprises would not be in what would dramatically change, but what would stay the same. Vespine (talk) 02:07, 5 September 2011 (UTC)

Note that conventional nuclear energy provides virtually "infinite energy", but it still costs a lot to produce it. Perhaps such a theoretical perpetual motion device might fall into the same category. If it takes a million dollars to produce a precision balanced device that only produces a watt a year, then it doesn't really solve the energy crisis. StuRat (talk) 02:09, 5 September 2011 (UTC)

I think this phrase from post scarcity is interesting: "[...] allowing manufacturing to be as easy as duplicating software". Yet some software costs thousands of dollars, due only to the effort it takes to write and test the software. Free energy, if it's sufficiently difficult to produce, might be even more expensive than conventionally-produced energy. --99.237.252.228 (talk) 06:47, 5 September 2011 (UTC)

This is more a Humanities (economics) question than a scientific question. Despite the lack of energy bills it would still be all too apparent that resources like food, lumber, land and so on are limited, and the wealthy would still expect to receive them as their birthright. With easy access to cheap energy, efficiency of industrial processes could be greatly reduced, so much less labor would be needed. You'd have more homeless than ever living in their cardboard boxes ... with free electric lights. And mass-produced robot spy sensors ensuring that they had to move every ten minutes or be rounded up and hauled off to jail. I suppose in a few decades the prison population might be 95% or more, mostly people convicted of being poor in one fashion or another. (I would differ from Player Piano (novel), because it seems to me that Vonnegut underestimated the tendency to enslave/criminalize unwanted labor e.g. under the Jim Crow system and the War on Drugs - prison is seen as such a perfect solution for the reformation of man, it is hard to picture denying its benefits to anyone if there weren't economic limitations) Wnt (talk) 07:12, 5 September 2011 (UTC)

Please say you don't mean "efficiency of industrial processes could be greatly reduced, so much less labor would be needed". Cuddlyable3 (talk) 08:18, 5 September 2011 (UTC)

For example, consider a production line for complex hybrid cars which are exquisitely designed for aerodynamics and to be strong while using minimal materials. With free power, you can create as much aluminum as you want from common rocks, fold it into heavy-duty, conveniently shaped vehicles, and replace the efficient engines with something simple. Worldwide, mechanized farming would largely displace small subsistence farmers - sort of like what the U.S. did to Mexico with farm subsidies, but far more extreme. Wnt (talk) 17:53, 5 September 2011 (UTC)

Either the first or the second laws of thermodynamics must be violated to make any perpetual energy solution happen, and of course, I would be the rebel that is actually making it, hence I will humor this inquiry and nail this bait FWIW. First and foremost, with exceedingly abundant energy, we can stop global warming in its tracks and even reverse it by not burning fossil fuels for energy and by also removing the current excess carbon dioxide in the atmosphere, if necessary, by cooling large volumes of air to liquify the CO₂ and use it to burn additional hydrocarbons to produce reserves of pure carbon (the CO₂'s oxygen is combined with the hydrocarbon's hydrogen to produce water, and yes its somewhat ironic that the process of burning oil might be an integral part of the solution to cleaning the planet's atmosphere). Thus we save the arctic's ecosystem in the near-term as well as perhaps the rest of this planet's ecosystems in the long-term. Also, our corn and sugarcane productions will not be needed for fuel, hence the prices of these will fall, which will help save land from excessive agriculture and help to lower global food costs. Furthermore, we will be able to shutdown nuclear plants to avoid future accidents and help us to stop nuclear proliferation. Expect too, a boom in automotive manufacturing for newer and better cars that don't burn gasoline and for transportation, in general, to be cheaper and more extensive (think of what it would be like to be able to go anywhere in the world without ever stopping for fuel). Thus, there will be less isolation of far-flung communities thus we should see increased globalization and better education as schools become considerably cheaper to maintain and use. Also, our economies will not falter or tank at all and quite the opposite, because there will always be a need for service providers and a need to design, manufacture or build, and maintain the things that make life more comfortable and entertaining. The overhead costs of brick-and-mortar businesses will be lower and delivery services will benefit from nonexistent fuel costs and as a result of increased business, as well as our manufacturers benefiting, because of the additional products we will be ordering without any of the large shipping and building maintenance expenditures on energy. I expect global tourism to increase and housing to boom again as people seek better housing conditions and more vacation homes. I would expect agriculture to change somewhat more gradually with improved irrigation systems and more extensive use of greenhouses. Wind and solar farms, hydroelectric dams, power grids, power lines and the recent storm outages should quickly become a thing of the past (not to mention strip-mining for coal, and the ongoing mercury pollution of our fishes). We will soon forget oil spills and fracking. With cheaper resources and virtually nonexistent energy costs, the world's population will also boom with the times (increasing demand for goods too), but I hope we will solve our need for additional space by migrating into space. Hence, we end up with a better civilization and that is the implication such that all in all, our future should be largely more successful and an improved adventure, into a sort of perpetuity, with our considerably more prosperous environment and economics. --Modocc (talk) 07:43, 5 September 2011 (UTC)

Note that cheap energy might cause temporary economic disruption, by putting most people in that sector out of work. However, in the long term, those people would likely move into other sectors. This process has happened many times in the past. For example, most people used to work in agriculture, but improvements in technology now allow us to make food much cheaper and with far fewer workers. The farm workers largely moved into other lines of work. Note, though, that this transition took place over many decades, and a quicker transition would cause more serious economic disruptions.

Viewed from the post scarcity POV, if energy becomes no longer scarce, then workers move into other areas where resources remain scarce. StuRat (talk) 16:20, 5 September 2011 (UTC)

A significant difference between some past technology transitions and for a rather rapid one for the energy sector, is that there will be numerous job opportunities that will be available, including those need for making the transition and into a post-transition world with the newer technologies and most adversely individuals should find a related niche to utilize their skills, perhaps moving into other sectors as these grow more rapidly. --Modocc (talk) 17:00, 5 September 2011 (UTC)

I would expect that many new jobs were also created when agriculture became more efficient. For example, all the power equipment like tractors had to be designed, built, and sold, and, since the foods were now transported much further, this required more transportation workers, and processed foods also became common, requiring more workers to process and advertise those foods. And I suppose you could argue that having all this cheap food available led to obesity, and hence many jobs created in the fitness and healthcare industries. StuRat (talk) 03:27, 6 September 2011 (UTC)

What property of electromagnetism is responsible for making individual things not everything?

Sorry, cant word it any better. basically, why is it that my particles do not merge/pass through other peoples particles? or why doesnt everything merge with everything else? whats the property that resolves this rather unintuitive situation? My subatomic dealies arent much different from other things subatomic dealies, and yet they remain seperate. Why?

Apologies again, I have a huge amount of trouble phrasing this phenomenon; since I dont know what its called i cant search to get an answer if one exists already here. 74.132.249.206 (talk) 01:17, 5 September 2011 (UTC)

Because the electrons on the outside of your "dealies" repel the electrons on the outside of other people's "dealies" because like charges repel each other. --Jayron32 01:19, 5 September 2011 (UTC)

It's actually a good question. According to physicists there are two basic types of particles, called bosons and fermions. It is possible for two bosons to be in the same quantum state, but it is not possible for two fermions to be -- and the particles that make up matter, such as electrons, protons, and neutrons, are fermions. (Photons, as an example, are bosons.) Looie496 (talk) 02:09, 5 September 2011 (UTC)

Looie is right. The relevant article is Pauli exclusion principle. Dauto (talk) 02:21, 5 September 2011 (UTC)

I'm not sure it has much to do with Pauli. The question is a reasonable one given that we are mostly made of "empty space" (whatever that may mean) to a first approximation. Most of the volume of an atom is nothingness, and we are made of nothing but atoms, so it is reasonable to ask why the atoms cannot essentially pass through each other; in other words, why my electrons couldn't just pass near (but not in the same space) as your electrons as we drift through one another. Pauli really doesn't deal with that issue. --Jayron32 02:30, 5 September 2011 (UTC)

You're mistaken Jayron Pauli exclusion principle plays a major role explaining why that doesn't happen. If you try compressing matter to densities higher than normal The electrons are forced to higher energy levels by the exclusion principle and that makes those high density states energetically disfavored. Dauto (talk) 02:44, 5 September 2011 (UTC)

Yes, but that doesn't necessarily explain why the electrons have to be compressed in the first place, instead of just passing near each other. For the record, I agree with you and understand the implications of Pauli WRT degenerate matter and all that it entails. I just don't think we've adequately explained why that would happen at all. I think we need to work on addressing the OP's question as to why the electrons need to be repeled at all; that seems to be the center of the argument. The Pauli exclusion principle issues are a "symptom", if you will, rather than a reason for the OPs initial confusion. --Jayron32 02:50, 5 September 2011 (UTC)

They can only pass near each other by going to higher energy level due to the exclusion principle. Electrostatic repulsion plays little role because matter is overall neutral. Yes, my electrons repel the next person's electrons, but my protons attract them. Dauto (talk) 03:16, 5 September 2011 (UTC)

Read Pauli exclusion principle#Stability of matter for an explanation and some references. Dauto (talk) 03:31, 5 September 2011 (UTC)

Yes, but your (and their) protons are shielded from each other, so the repulsive force of the valence electrons on each other is greater than the attractive force between the valence electrons and the other atom's protons. The question still comes down to why the electrons must be forced into the higher energy levels because of the exclusion principle. The exclusion principle is the mechanism by which they will do so, but it doesn't really provide the answer for the OP what it is about the exclusion principle that requires it to be invoked in this case. Note, that I am not disagreeing with you fundementally here on the use of the exclusion principle, but the OP deserves an answer which explains why it needs to be invoked here. It's obvious the OP is unfamiliar with the physics here, and merely directing them to an impenetrable article about the Pauli exclusion principle doesn't really adequently add to their understanding. You might as well have directed them to the article as it is written in Swahili, for all that reading it would add to their understanding. What is needed here is a simple explanation of why it applies, and what the implications are. Merely repeatedly saying "It's because of the Pauli exclusion principle" doesn't make it more understandable. I am not arguing with your correctness, so let me reconfirm that you are correct, and you continue to be correct. So you don't need to convince me of your being right Dauto. I just wish to see this explained in a way that makes it understandable for someone who has does not have advanced degrees in a narrow field of physics. --Jayron32 03:35, 5 September 2011 (UTC)

Lets think about a space with just one dimension for simplicity and lets ignore niceties such as spin angular momentum, and so forth. Lets put now some electrons in a box (which in one dimension is simply a line segment). Electrons are represented by standing waves in this line segment. Only certain discrete values for the frequency are allowed - These frequencies are called harmonic frequencies. The Higher the frequency of the harmonic, the higher its energy. If electrons did not follow the exclusion principle, they could all be at the fundamental frequency (lowest energy state), but they do follow that principle which means that every new electron added must have higher energy than the one before it. That means it takes a lot of energy to compress all those electrons together. That translates as a repulsion force between electron which has nothing whatsoever to do with electric repulsion (For instance, it a similar repulsion acts on neutrons and neutrinos). I hope that helps. Dauto (talk) 05:00, 5 September 2011 (UTC)

The Pauli exclusion principle explains the difficulty of compressing matter (liquid or solid) beyond a certain density, but it doesn't explain why solids don't mix together on contact like liquids do. To explain that you need to talk about the interatomic bonds, which are electromagnetic (though the exclusion principle is also involved). It's those bonds that make it difficult to "push through" (really push aside) a solid. I don't think the electromagnetic repulsion of electrons at the surface of the two solids is a significant factor. I'm not terribly certain about any of this, though. -- BenRG (talk) 09:03, 5 September 2011 (UTC)

Electrons can always be modeled as within orbitals; interatomic bonding can be explained by molecular orbital theory. --Jayron32 19:54, 5 September 2011 (UTC)

• I have some related questions. My fingers aren't chemically active with my keyboard in a manner I can observe during a day. But my fingers appear to be mechanically active with the keyboard over a long period of time, as they wear off "keyboard snot" from the keycaps. I can handle the idea that my fingers are made of chemicals that are in a non-reactive state, and further, that they won't be made chemically active from the amount of heat I can apply while typing. But now I'm having difficulty figuring out why sections of my skin mechanically flake away (surely the chemical bonds holding my skin to itself have weakened to allow this?). Bits of me fall off sometimes, but at other times bits of me remain me. These don't seem to be mixtures, like when I exhale, or add water to milk. Similarly some other solids (slate) break in one direction readily but not in another due to their chemical structure. Other solids, like chalk, are very soft. Does the strength of chemical bonding determine all of these hardnesses? Fifelfoo (talk) 04:53, 6 September 2011 (UTC)
  • Yes, pretty much. There are, of course, different kinds of "bonding", generally "intramolecular bonding" (which holds the atoms in a molecule together) is much stronger than "intermolecular bonding" (which holds neighboring molecules to each other). However, that sort of classification only works for molecular substances (of which, you are mostly composed). There are also substances which have ionic bonding, network bonding, metallic bonding, etc. where the substance is not composed of discrete molecules. --Jayron32 05:20, 6 September 2011 (UTC)

Anatomy of a UFO

Where can I find a diagram of what the inside of a flying saucer looks like? Preferably either by someone who claims to have been abducted by aliens and seen or photographed the inside or by someone who claims to have recovered a crashed UFO. 75.36.232.223 (talk) 07:13, 5 September 2011 (UTC)

I don't see how this is a question appropriate for the Science Reference desk. Have you tried asking it at an extraterestial enthusiast blog? Plasmic Physics (talk) 08:03, 5 September 2011 (UTC)

Wikipedia has an article with diagram of the patented British Rail flying saucer or you can browse through these flying saucer diagrams. Cuddlyable3 (talk) 08:05, 5 September 2011 (UTC)

Also, there's this flying saucer diagram, which I hope you find helpful. Clear skies and tailwinds 67.169.177.176 (talk) 05:02, 6 September 2011 (UTC)

Plenty of people that have claimed to have seen UFOs of been abducted by aliens have drawn pictures of what they saw. I don't think any of them are notable enough to have Wikipedia articles about them, though. You would be better off searching for the original accounts (google will find you hundreds). --Tango (talk) 11:35, 5 September 2011 (UTC)

Some scientists of the 1880's doubted reports of sightings of gorillas. Earlier 19th century scientists doubted that meteorites fell from the sky. Yet sightings were discussed and debated in the scientific journals of the time. Diagrams of objects doubted by scientists are on the fringes of science, but still merit discussion on the science ref desk as opposed to the other desks. Abnormal psychology is also a part of the Science Ref Desk, as are delusions and hallucinations as studied by psychiatrists. Serious books have reported saucer sightings, and university based scientists such as Hynek have studied such reports over many decades. Edison (talk) 16:35, 5 September 2011 (UTC)

We have a pretty interesting article Narrative of the abduction phenomenon. Personally I would take this as science fiction, on account of the hypnotic regressions being used; people's memories tend to be most reliable when they're not told what to remember. But the sources probably have some image somewhere of the "crystals and rotors" in the engine room. Wnt (talk) 18:53, 5 September 2011 (UTC)

The French author Robert Charroux in his book The Mysterious Unknown" Corgu 1973 shows between pp. 224-225 a diagram section of a "vaïdorge" which appears to be a kind of UFO.[1] in which a man travelled in 1940s. You can see the same diagram here (website in French) labelled vaïdorge bâavienne. Unconfirmed information that "the common double oblate hemisphere shaped "flying disk" is called by its owners a Vaidorge Diapason, or Metadorge." may be useful for investigating further. Cuddlyable3 (talk) 21:32, 5 September 2011 (UTC)

Geomagnetic propulsion using sources of power such as zero-point energy. ~AH1 ^(discuss!) 23:22, 6 September 2011 (UTC)

products of grains

Where can I find a list of how much of a particular product can be made from a particular grain? For instance, how many ounces of ethanol can be made from a bushel of wheat or corn versus how much bread. --DeeperQA (talk) 11:39, 5 September 2011 (UTC)

You should expect the answer to vary over several orders of magnitude depending on the exact process. Numerous confounding variables will include the financial cost of the process, the equipment required, and the scale that the conversion is taking place at.

• I am not interested in economic statistics. My question is strictly addressing the physical, mechanical and chemical process with all other variables such as quality of the grain being the same. --DeeperQA (talk) 09:42, 6 September 2011 (UTC)

Here is an example set of statistics from the Energy Information Agency: Fuel Ethanol Overview, 1981-2009. You can compare the feedstock input, byproducts, denaturant inputs, and look at the production output.

Here are statistics from an independent organization, the Renewable Fuels Association (an industry trade group): Weekly Ethanol Feed Production statistics. As you can see, the inputs and outputs are listed; but again, the question you're asking seems to imply that equal quantities of "input product" could yield either bread or ethanol. This is not an appropriate way to analyze the problem: for example, it doesn't matter how many pounds of turpentine and corn oil you start with: you can't bake that into bread. So, you probably need to research the methods of ethanol production so that you can reformulate your question in such a way that we can point you towards a meaningful statistical comparison. Nimur (talk) 17:11, 5 September 2011 (UTC)

Ideally you're not making ethanol out of the corn, but out of the silage ("corn stover", according to corn ethanol). But it doesn't sound like that's what's actually happening. Wnt (talk) 18:57, 5 September 2011 (UTC)

You'll need to get friendly with some termites first though! SmartSE (talk) 19:16, 5 September 2011 (UTC)

I don't think we will find a list, but if it helps, last year The Guardian reported that US corn ethanol could feed over 300 million people. You could also look at Ethanol_fuel#Efficiency_of_common_crops. SmartSE (talk) 19:16, 5 September 2011 (UTC)

I do not want to know about cost or any other factor just how much bread can be made from wheat and from corn versus how much ethanol can be made from wheat and corn. My question is similar to how much carbon dioxide can be made from a tank of oxygen versus how much water with no concern about the carbon or hydrogen involved. --DeeperQA (talk) 09:51, 6 September 2011 (UTC)

Circular orbits

Are all the orbits of the planets and moons thought to have been circular, originally, with any eccentricity due to perturbations by passing objects ? If so, could a computer program be used to recreate the mass, velocity, and location of those passing objects ? StuRat (talk) 19:11, 5 September 2011 (UTC)

There is no reason to believe that any particular orbit was ever perfectly circular. The process of collision and accretion that formed planets and moons would have provided random perturbations even at the very beginning. Dragons flight (talk) 19:20, 5 September 2011 (UTC)

My guess is that the perturbations made the orbits more circular. The orbits are much more circular than you would expect by random chance (OK, no, I haven't actually worked out how circular you'd expect them to be by random chance). --Trovatore (talk) 19:39, 5 September 2011 (UTC)

What a Nice model indeed! ~AH1 ^(discuss!) 23:19, 6 September 2011 (UTC)

Nutrient content of human waste

Can anybody find figures for the amount of nutrients contained in the faeces and urine we produce in a year? I'm most interested the amounts N P and K but others would be great. Also, do the amounts vary depending on the food we eat? Thanks SmartSE (talk) 19:23, 5 September 2011 (UTC)

The phrase "shit eating grin" comes to mind...And oddly, shit eating is a blue link, but for some reason there is no nutritional analysis. Beeblebrox (talk) 19:36, 5 September 2011 (UTC)

The N, P, K comment makes me think that the OP is looking for the use of human waste for fertilizer (i.e. plant nutrition). Smartse, you'll want to start looking around, probably outside of Wikipedia, for research regarding night soil and humanure, two terms which refer to human waste used to fertilize plants. --Jayron32 19:50, 5 September 2011 (UTC)

Yep that's correct - I want to feed it to a compost heap rather than eating it myself... I knew of humanure before, but didn't search for it - now I've found this which gives hypothetical values, but still no actual analysis of shit (I managed to find them for cows, horses and grasshoppers)! SmartSE (talk) 20:27, 5 September 2011 (UTC)

MIT did a great deal of research on this very topic in the 1960s - one group was fed glop, and another a high-protein steak diet. They did have problems finding anyone with staying power for the first group. As I understood it, NASA funded some of the studies. Cheers. Collect (talk) 21:51, 5 September 2011 (UTC)

Miscibility

Is it true that for instance oil and water, two immiscible liquids on Earth, are miscible in absence of gravity?If yes, how could that be be explained theoretically?--79.119.213.134 (talk) 21:58, 5 September 2011 (UTC)

They aren't really miscible in the absense of gravity; but if shaken vigorously, they will not easily seperate, since the difference in density between oil and water is the reason the seperate on earth; with no gravity such difference won't show up. You can still seperate them fairly easily, however, with a centrifuge. --Jayron32 22:26, 5 September 2011 (UTC)

No, solubility has nothing to do with gravity. Plasmic Physics (talk) 22:30, 5 September 2011 (UTC)

Remember, mixing is not the same as solvation. Plasmic Physics (talk) 22:41, 5 September 2011 (UTC)

Oil and water shaken together can form a colloid called an Emulsion, see article. Cuddlyable3 (talk) 08:55, 6 September 2011 (UTC)

Why most of the time the temperature indicator remains on in Fridge?

I have a fridge running smoothly since 2004. Suddenly, I noticed that the temperature indicator (yellow light) remains on for several hours and then it comes back to the normal condition. During that time, ice and other groceries melts away. It usually happens at afternoon (1 pm to 4 pm) and at morning (4 am to 6 am).Thanks--NAHID 22:03, 5 September 2011 (UTC)

Something is broken; it may be time to get a new fridge. Yes I know that a) it isn't that old and b) SERIOUSLY, it isn't that old; but I had something similar happen to a fridge and when I had the repair guy come out to fix it, he said "I can fix it; but by the time I am done you can get this same model fridge for about the same price." YMMV, but be prepared for a significant expenditure in your future. --Jayron32 22:24, 5 September 2011 (UTC)

Well it depends on what kind of fridge.. I mean the fact that there are still "fridge repair guys" should indicate that they can fix at least some fridges. The more expensive the fridge the more likely it is worth fixing it.. If it was a cheapo "my 1st fridge" then yeah, probably just get a new one. Vespine (talk) 22:30, 5 September 2011 (UTC)

You already asked this question on the Computing desk -- did you look at the answers you got there? Looie496 (talk) 23:34, 5 September 2011 (UTC)

I don't know what your "temperature light" actually indicates. You can buy a refrigerator thermometer for under $5 US.If you open the door and stare at the thermometer, the temperature will rise and stay high for several minutes. Or you can place a glass of water in the frig and measure the temperature with any random thermometer covering the refrigerator temperature range. That method is less subject to rises from you opening the door. See a discussion of proper frig temp here. I had one frig with a bad door switch, such that the light bulb inside stayed on with the door closed. Have you recently (or ever) vacuumed dust off the evaporator coils under the frig or perhaps behind it? Might wish to unplug it and do some cleaning. I had a repairman out for a restaurant type frig which wasn't cooling due to a slow leakage of freon, which had the temp up in the 50's F. The desired temp was around 34F. This caused the coils in the frig to ice up (yes it seems paradoxical) and not cool efficiently. It cost about $190 for the guy to come out, do a pointless leakage test with soap bubbles and a freon detector (the leak takes over a year to be a problem, and these testers are not sensitive enough to detect it.) Then he squirted in some freon and it worked fine. The manual says the external coils on the commercial frig should be vacuumed once a month. A more refrigerator typically defrosts the freezer compartment once or twice a day, with a heating element. This could cause periodic temperature rises, but they should not be so high that food spoils.

excess sugar & diabetes

What happens to the excess sugar that isn't stored in the liver of a diabetic person?--72.145.142.125 (talk) 22:51, 5 September 2011 (UTC)

Diabetes_mellitus#Signs_and_symptoms covers some of this. --Jayron32 01:00, 6 September 2011 (UTC)

Does the excess glucose turn into triglycerides?--72.152.251.241 (talk) 01:49, 6 September 2011 (UTC)

Actually, what happens to it is even worse -- some of it binds randomly to proteins and renders them nonfunctional (e.g. proteins in the eyes, etc.), and some of it turns into acetone, which builds up in the bloodstream and impairs its oxygen-carrying properties. This can lead to some very dangerous effects in the long term. 67.169.177.176 (talk) 04:37, 6 September 2011 (UTC)

Did I miss the part above about it coming out in the urine? Diabetics "spill sugar" when blood glucose levels are above a threshold, urinate frequently, and are always thirsty. This is the most common sign of diabetes. Some doctors have called it the "shoe sign:" the poorly controlled or undiagnosed male diabetic has sticky, white or shiny spots on the top of his shoes from splashes of sugar-laden urine while urinating. Edison (talk) 19:47, 6 September 2011 (UTC)