Wikipedia:Reference desk/Archives/Science/2007 February 6

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[edit] February 6

[edit] The 'pill' equals weight gain?

A couple of days ago I was reading the local newspaper's science page. One of the columns was a Q&A about science topics. The question was whether or not the 'Pill' really caused weight gain (or how). The answer was that, while older types of the pill did cause weight gain, newer ones had a different balance of hormones that did not cause much weight gain. The Doctor went on to say that the reason so much weight gain was from a natural increase of weight around the typically time the pill started to be used (IE 16 years or such)

Is this true? --HoneymaneHeghlu meH QaQ jajvam 00:16, 6 February 2007 (UTC)

The authors of an academic study into that very question (Gallo M. F., Lopez L. M., Grimes D. A., Schulz K. F. & Helmerhorst F. M. Cochrane Database Systematic Rev., doi: 10.1002/14651858.CD003987.pub2. (2006)) conclude that:

'cause and effect' is merely anecdotal, and that patterns of weight gain among new pill users are no different to those seen in the population at large. The most logical explanation is that all of us, men and women, gain weight with age. The average American, for example, gains about one pound (0.45 kilograms) every year, but most people seek out something to blame for this other than their personal behaviour. [1]

Rockpocket 01:22, 6 February 2007 (UTC)
Should the article be changed to reflect this?--HoneymaneHeghlu meH QaQ jajvam 23:10, 6 February 2007 (UTC)
Why not be bold? Rockpocket 07:35, 7 February 2007 (UTC)

[edit] air in potato chip bags

why is there so much air in potato chip bags? Is anything else a factor for their freshness?

It's in part to discourage breakage. Anchoress 00:46, 6 February 2007 (UTC)
Air would actually make the chips spoil faster because of the oxygen; I believe nitrogen gas is used instead of air. (Potato chip makers in Korea state that they use nitrogen.) --Kjoonlee 00:55, 6 February 2007 (UTC)
Was that a response to my comment? Because my point was that when the bag is inflated (with whatever gas) to maximum size the chips are less likely to break due to compression or impact during the journey from manufacture to sale. Anchoress 17:54, 6 February 2007 (UTC)
I'm sorry, I meant my reply to point out that the original question had a weak point. I agree wholeheartedly with your comments. :) --Kjoonlee 18:36, 6 February 2007 (UTC)

I always thought air in the bag was just to make it look more full then it is so that the person buying it wont feel as bad when they pay $3 for 10 ounces of chips. Maverick423 14:37, 6 February 2007 (UTC)

Except it isn't air, as mentioned above; Korean manufacturers state it very clearly: "Filled with nitrogen to protect contents." --Kjoonlee 15:09, 6 February 2007 (UTC)
Ooh, the potato chip article confirms the use of nitrogen. Isn't Wikipedia wonderful? :) --Kjoonlee 15:15, 6 February 2007 (UTC)

Yes very intresting info well i guess you learn something new everyday =) Maverick423 16:30, 6 February 2007 (UTC)

[edit] Point to point Rocket travel: How is it possible to get from any point on Earth to another in just 45 minutes?

Hello Volunteers:

I've tried to research Point to point Rocket travel: How is it possible to get from any point on Earth to another in just 45 minutes? All I'm able to locate is information about rocket/space travel and how point-to-point rocket travel can be done in 45 minutes etc...but I haven't been able to locate any info on how it works...why does it take only 45 minutes... ?

thanks in advance for all the answers

Shaum76 01:09, 6 February 2007 (UTC)

An object in a low Earth orbit (LEO) takes about 90 minutes to complete one full orbit of the Earth. Now, think of a point-to-point rocket journey as a rocket in a slightly flattened (elliptical) orbit that intersects the surface of the earth at your departure point and at your destination. Neglecting the (relatively short) periods of acceleration at takeoff and landing, the furthest point on Earth from you will be no more than half the circumference of the Earth away (half an orbit): 45 minutes.
It is in principle possible to get from point to point even faster, but only at ruinous cost of fuel. A faster trip would essentially require you to burn fuel the whole way, instead of coasting for most of the trip. TenOfAllTrades(talk) 02:03, 6 February 2007 (UTC)

You can do better than 45 minutes (actually about 42) using a Gravity train. Bunthorne 06:56, 6 February 2007 (UTC)

[edit] Light: Vector or Scalar?

Me and a few of my friends at school have been debating whether or not light is a vector or scalar quantity. Is it the SPEED of light, or is it the VELOCITY of light? What is the convention used and how does light actually travel, and what are the reasons for this?67.70.30.223 02:01, 6 February 2007 (UTC)Adam Reid

Light is neither; its speed is a scalar and its velocity is a vector. Scalars and vectors are not mutually exclusive. I don't understand what you mean by how light actually travels. Clarityfiend 02:49, 6 February 2007 (UTC)
Light is vector. It has energy and a direction. Interactions with other particles with vector properties preserves the vector/vector rules, not vector/scalar rules. Light has momentum which is the inherent vector quantity. Tbeatty 03:22, 6 February 2007 (UTC)
I don't think you can classify light as vector just because it has energy and momentum. For example, you can not say that a moving car is a vector. Scalars and Vectors are physical quantities and not objects. But as Clarityfiend mentioned, if you say velocity of light, then you need to mention the direction too, because velocity is a vector. You can say 'the speed of light is so and so' but if you say 'the velocity of light', then you should specify 'in the eastern direction' or something like that. -- WikiCheng | Talk 13:15, 6 February 2007 (UTC)
If you're thinking of light as an object, the above answers are correct: its speed is a scalar, but it's velocity is a vector. To muddy the waters, and not at all because I think this is what you were debating about, in electrodynamics, light is described by the electromagnetic four-potential; in quantum electrodynamics (the quantum-mechanical version), individual photons are little localized packets of this field. From this perspective, light is a vector after all, and photons are one example of a vector boson. (Any particle with spin of 1 unit, like the photon, is a vector; those with a spin of 0 units would be scalars.) -- SCZenz 13:38, 6 February 2007 (UTC)

[edit] Too much tea?

I drink a lot of tea - at least 3 and sometimes up to 6 or 7 cups a day of green tea, white tea and regular black tea. I drink soy milk with black tea but I don't use sugar. I also consume other antioxidant-rich things like red wine and cranberry juice on occasion. Are there any possible negative side effects of so much tea consumption? --Grace 02:39, 6 February 2007 (UTC)

Yes you can have too much caffein and get the jitters or insomnia. Also your teeth may be discoloured by too much tea. Is soy milk with black tea called white tea though? GB 05:52, 6 February 2007 (UTC)

By the way, you know consuming too much antioxidants can be unhealthy, mostly happens with vegetarians though, but you seem like you get a lot. [Mαc Δαvιs] X (How's my driving?) ❖ 07:06, 6 February 2007 (UTC)
Overconsumption of too much of one particular antioxidant chemical has been linked to health problems, but tea contains so many I don't think it's something to be worried about. (I don't think anyone has ever been diagnosed with antioxidant overconsumption from food, vegetarian or not). There are many folks who drink many cups of antioxidant-rich green tea a day with only positive effects that we know of. Also, white tea is a different variety of tea, similar to green tea. Frankg 15:28, 6 February 2007 (UTC)
You might be interested in this article: Heart study pours cold water on adding milk to tea. Anchoress 15:33, 6 February 2007 (UTC)
Thanks for your answers everyone...Mac Davis, what's wrong with consuming too much (too many?) antioxidants? In the article it mentions that they may prevent your body from using other important nutrients, would taking vitamins offset this? --Grace 23:49, 7 February 2007 (UTC)
Taking vitamins is the usual way that people harm themselves by antioxidant overconsumption. According to this, the mechanism isn't known for sure. "Antioxidant" mostly means reducing agent, though, and any kind of strong chemical will produce chemical reactions that can harm your body, if taken to excess. As other folks have said here, even extraordanary amounts of tea probably don't add up to excessive quantities of antioxidants.--Joel 10:02, 12 February 2007 (UTC)

[edit] Dirty Glass Recycling

Some people put dirty jars in glass recycling bins. Are these jars just fed into a the glass melting machine all dirty or what? What about the label? What about the glue residue that attaches the label to the glass? --Seans Potato Business 04:28, 6 February 2007 (UTC)

When I talked to the local recyclers about this they said there was no need to wash out leftovers or remove labels. The glass material is sorted out and the company washes it anyway, and then melts it down. However they don't want light globes, window glass, pyrex or any other weird kinds of glass that muck up the mix. You may wish to wash out the remains to cut down on odor as it decomposes though. The same story applied to metal cans for recycling. GB 05:50, 6 February 2007 (UTC)
I'd agree with GB. Glass melts at such a high temperature that most things would just burn off. Any other oddities left behind (metals etc.) could just be separated out by density. --Cody.Pope 07:36, 6 February 2007 (UTC)
Yes and no. Plenty of organic stuff, I'm sure, burns off without a trace. But glass is a pretty weird substance, and even when molten it's still very, very viscous. Lots of metals and minerals can remain intermixed with it and do not by any means separate out by density. Trace amounts of various metals and minerals are routinely added to glass to give it desired colors or other properties. But those elements, if present in waste glass, can't be used to make a new batch of glass if those elements aren't desired in the new batch. That's why window glass is not welcome in the recycled glass stream. Also, I learned during a visit to a glass recycling plant that even one green bottle mixed in with several thousand clear ones can ruin a batch of clear glass. —Steve Summit (talk) 13:10, 6 February 2007 (UTC)
[Footnote: I said that "even when molten glass is still still very, very viscous". Let's not hear anything about the urban legend of its alleged viscosity at room temperature, 'kay? —s]
A lot of recycled materials are not sold as "virgin" versions of the same substance, such as paper. Old milk cartons go to make park benches, not new milk cartons. I wonder if old recycled glass likewise gets downgraded to brown or green glass or non-seethrough glass products. It would seem silly to try to have perfect clear windoe or bottle gmass when one speck of adulterant would tint it. The glass gets smashed to bit, then a furnace burns away bits of paper or glue or spaghetti sauce, then I expect some of the other undesired substances float to the top as scum or slag and get skimmed off. I have always been doubtful of the need to run empty jam jars through the dishwasher or to scrub them in the sink, due to the water and fuel energy wasted. Edison 18:26, 6 February 2007 (UTC)

[edit] Trees

what is Adenanthera pavonina,L.?

It's red sandalwood, here's a page I found via google: http://www.tropilab.com/adenan-pav.html. By the way, in future, it's probably a lot quicker for you to search on google, or some other search engine for that matter. All the best. - Akamad 05:04, 6 February 2007 (UTC)

[edit] Torpedo away

According to U-Boat#World War II, a magnetic torpedo worked by exploding underneath a ship, creating an air bubble that displaced the water supporting the weight of the ship; the unsupported hull then buckled. Is this true? Clarityfiend 04:39, 6 February 2007 (UTC)

It does not sound like a true statement, as an exploding torpedo would increase the pressure, lifting the ship. The gas bubble should be able to support the ship due to its high pressure. Much of the damage would be due to the blast shock wave. GB 05:45, 6 February 2007 (UTC)
My mistake. The article mentioned the air bubble, but the rest was my hallucination. Clarityfiend 06:42, 6 February 2007 (UTC)

Actually I've heard the exact same thing - twice - from ex-naval people - though not torpedos - more mines - the mine explodes - releasing a lot of gas - the gas expands becuase it is under pressure - creating a huge gas bubble under the target - and because gas doesn't have the buoyancy of water the ship sinks - that's the theory - just because I heard it from a good source doesn't mean it has to be true.87.102.37.127 06:55, 6 February 2007 (UTC)

It's not accurate. Refrence [2] for a complete description. Hipocrite - «Talk» 14:33, 6 February 2007 (UTC)

[edit] Effect of radiation/nuclear bomb on U.S. currency tests

I heard from a reliable source that the U.S. had conducted tests concerning the effects of radiation/a nuclear bomb on United States currency. However after doing a little reaserch I was unable to find any information on any test or tests pertaining to this subject. If anyone knew any information concerning this (i.e. date, place, test name, results, ect.) please enlighten me.

Mattheyborne 04:53, 6 February 2007 (UTC)Matt

If the currency (notes or coin) was near enough to the bomb, it would be destroyed (vaporised)--DarkFuture 06:19, 6 February 2007 (UTC)
Despite what Mattheyborne says: I have heard about different types of Nuclear Weapon which are designed to produce a huge amount of fallout without much actual explosive yeild. for example to kill the inhabitants of a city without actually causing much damage to infrastructure. the information about this type of bomb can be found here. Not sure if this helps, but i hope so. Ben
You're talking about a neutron bomb, although why the government would be overly concerned about the survivability of currency in the event of a nuclear war is beyond me. You'd think it would have more immediate worries. Clarityfiend 17:21, 6 February 2007 (UTC)
Governments generally assumed that nuclear warfare would not in fact end the world or their governments, but that it would be seriously disrupting. This is the "thinking the unthinkable" that think tanks did best at, realizing that there would in fact be survivors in almost any conceivable nuclear war and that one shouldn't simply close one's ears to the possibility because it was horrific. On the other hand, Lynn Eden at Stanford has recently published a book (Whole World On Fire) which in my mind conclusively demonstrates that the think tank theorists did not adequately take into account the fire effects of bomb shots, concentrating instead only on blast, heat, and radioactive effects, and in that sense probably severely underestimated the effects of nuclear weapons on inhabited areas. --140.247.250.21 17:38, 6 February 2007 (UTC)
They definitely tested the results of atomic blasts against a Mosler bank vault during their civil defense-related testing at Nevada Test Site in 1957 (it is still there). These tests were done in the context of houses and facilities not at the epicenter of the blast, but some distance away. The assumption was that the world would in fact not end in such a salvo (and in the 1950s there were not enough warheads to really be "world-ending" in the possession of the USSR) and that things like material property would still be quite important. This was two decades before the so-called "neutron bomb" was developed. --140.247.250.21 17:35, 6 February 2007 (UTC)

perhaps the original poster means the economy as opposed to the actual money, i could see governments taking lots of interest in disaster secanios and what would happen to prices etc --137.205.79.218 09:08, 8 February 2007 (UTC)

[edit] Job requirements: Spectroscopy and chromatography

I have an interview for a co-op job that asks for knowledge of ultraviolet-visible spectroscopy and infrared spectroscopy, as well as gas chromatography. Now, I have experience with spectrophotometry and spectroscopy, but not specifically UV/VIS nor IR. Also, I have done paper chromatography, but not gas chromatography. This one seems more complicated .

My opinion is: spectroscopy is spectroscopy is spectroscopy. Am I being cocky, or are UV and UV-VIS quite different from regular (emission / absorption) spectroscopy?

Also, gas chromatography seems much more complicated than paper chromatography. Are these techniques that I can quickly learn, considering my previous experience? − Twas Now ( talk • contribs • e-mail ) 06:53, 6 February 2007 (UTC)

uv spectroscopy is a type of electronic emission/absorbsion spectroscopy.
Gas chromatography (see http://www.gchelp.tk/ from that page for help) is more complicated than paper chromatography.
My guess is that they would like people who have experience operating uv spectra machines and gas chromatograph machines.
If you've used any spectroscopy machine (eg IR spec) before then using a iv or uv/vis machine should be simple for you to grasp - there's not a big difference in the way they are set up.
Gas chromatography is more complex - there's an oven, temperature control, it all depends on how much you are expected to do - just running a spectra would be simpler than setting up the machine, which in turn is simpler than knwoing how to set up a machine for a given sample. I'd expect at least some training - but anyone with experience would probably get first choice..
Recommend you read the two links above for GC and good luck. That's the best I can offer.87.102.37.127 07:02, 6 February 2007 (UTC)
Thank you, that external link is great! If anyone else has some other comments, they would be appreciated. − Twas Now ( talk • contribs • e-mail ) 08:11, 6 February 2007 (UTC)

[edit] Sodium laurel sulphate and sodium laureth sulphate.

I was just wondering... what are sodium laurel sulphate and sodium laureth sulphate and what do they do? Either one of those chemicals seems to be one of the first ingredients listed on all my shampoo bottles. --Candy-Panda 09:37, 6 February 2007 (UTC)

Both are detergentia or tensides or simply spoken soap. --Stone 10:43, 6 February 2007 (UTC) Sodium laureth sulfate might help.--Stone 10:45, 6 February 2007 (UTC)

Also Sodium dodecyl sulfate is sodium lauryl sulphate - they are quite similar - but not the same. Note detergent is a better term than soap - soap is typically Sodium tallowate or very similar - as found in a bar of soap. Sodium laur-- sulphates are more likely to be found in a liquid detergent such as Fairy Liquid.87.102.13.26 14:06, 6 February 2007 (UTC)
They're the primary cleaning agents in shampoo.87.102.13.26 14:06, 6 February 2007 (UTC)

[edit] 1,3 butadiene

Do you have any information about a plant in India and Poland manufacturing butadiene from ethanol by two step process?

JACS paper 1949 might be an old process?--Stone 11:59, 6 February 2007 (UTC)
Ethanol to actaldehyde to crotonaldehyde to butadiene with Ta2O5 at 350°C. The paper was first hit in google scolar with butadiene from ethanol

[edit] Heart deposits

Suppose you had HDL deposits in your heart, and you were to have a totally fat free diet, would they then melt away??

Fat is synthesized in our body! HDL free or better cholesterol free would also not benefit, because it is a key component of cellmembranes.--Stone 13:06, 6 February 2007 (UTC)

High density lipoprotein (HDL) is the so-called "good cholesterol". A totally fat-free diet would be quite unhealthy, as fats are required! For example, they help in hormone production and the digestion of vitamins A, D, E, and K. Check out the article on essential fatty acids. − Twas Now ( talk • contribs • e-mail ) 14:04, 6 February 2007 (UTC)

[edit] Acidity level of free fatty acids from waste cooking oil

Greetings,

How to check the acidic and content level of free fatty acids from waste cooking oil WITHOUT going thru lab tests..?As in..Can we use cetain chemical or device which we can test on our own...?

A flask some phenolphthalein, pipet, sodium hydroxide solution of a known concentration, and you can start your job. Titration os simple!

I would have liked to have said that but oil doesn't mix with water - making the titration most difficult.87.102.13.26 15:42, 6 February 2007 (UTC)
Mixtures of alcohols help!--Stone 17:52, 6 February 2007 (UTC)

[edit] Wellbrutrin

I read that Wellbrutrin increases sexual urges in women. How does this happen?

It could suppress inhibitions. Corvus cornix 16:52, 6 February 2007 (UTC)

I think I would have to disagree. I believe that something chemically is happening...

for info on stuff like this check here http://people.howstuffworks.com/valentines-day.htm

and for more percise info on it check here http://health.howstuffworks.com/aphrodisiac.htm

Maverick423 17:41, 6 February 2007 (UTC)

Does anyone know what takes place chemically?

Speculations on what takes place chemically are located on the http://health.howstuffworks.com/aphrodisiac.htm article. however i dont think anyone knows forsure what happens with aphrodisiacs because there are alot of factors to consider.Maverick423 18:27, 6 February 2007 (UTC)

The thing is is that this is a anti-depressant, as in the description under Bupropion in Wikipedia: "Patients who complain of sexual dysfunction as a result of their SSRI have sometimes been prescribed small doses of bupropion, amphetamine or methylphenidate to correct it.[5]" Does anyone know how chemically this is affecting the human body?

A 2006 article (doi:10.1093/annonc/mdl304) notes "The mechanism by which bupropion has prosexual effects is unknown." DMacks 19:54, 6 February 2007 (UTC)
Does anyone else find this question a bit creepy? − Twas Now ( talk • contribs • e-mail ) 07:06, 7 February 2007 (UTC)

This is for Twas Now, I am the female who typed this question, is currently taking Wellbutrin and experienced the side effect mentioned in the question. There is absolutely no reason for you to underestimate my intention to gain more knowledge. I find you creepy for thinking so! In the future, I suggest that you do NOT answer anybody else's questions because no one appreciates your stupid comments!

Yes, I bet you are female. How did I underestimate your intention to gain more knowledge? Through the process of questionizationing? Oh I love verbal superfluousness.
Check out our article on bupropion (a.k.a. Wellbutrin) and please remember to sign your questions with the ~~~~ tag. − Twas Now ( talk • contribs • e-mail ) 10:13, 8 February 2007 (UTC)

Twas Now (or never), you must be a womanizer or maybe you hate your mother but, again, I asked that you NOT contribute to this question. If you have any reading comprehension skills, you will see that I had already reviewed the article on bupropion in Wikipedia and, had you read such article, you will see that it doesn't, like you, answer my question. I also will like to know where I could submit a complaint on this forum.

I didn't know that was your comment, since you forgot to add four ~'s to sign your name (~~~~). Anyway, have a look at Wikipedia's suggested dispute resolution procedure. − Twas Now ( talk • contribs • e-mail ) 14:27, 8 February 2007 (UTC)

[edit] How to make?

Asked this question on the nitrocellulose page however seeing as how people dont really respond to them on there im asking it here .

how do you make gun cotton or where can i get flash paper and is it possable to make flash paper??

buy it from magic or theatrical effects suppliers. Try searching on "flash paper" +cotton +cord --Wjbeaty 02:13, 8 February 2007 (UTC)

the reason for this is for a film me and some friends want to make however we cant find flash paper (not even in magicians stores)

Also how does one go around making that Fireball from flash paper? you know the one that looks like its a supernatural power comming from the persons hand? in anyways thanks in advance !!! One more thing whats the safest distance to be at when making a fireball from your hand? (in the term of the other "object") Maverick423 17:33, 6 February 2007 (UTC)

My heart bleeds for you! When I was a kid, I read books on how to make home-made explosives, rocket fuel, etc. I ordered flash paper through the mail, and I made my own guncotton. In this day and time, I wouldn't touch your request with a ten foot patch cord... :) --Zeizmic 17:55, 6 February 2007 (UTC)
The synthesis is easy, but dangerous. The ingrediants are hard to get and even harder to dispose. And if you really search for it you will find a good synthesis description from a person which is careless and stupid enough to distribute it over the net.--Stone 18:03, 6 February 2007 (UTC)
  • crys on Zeizmic's sholder" WHY!!!!! man dude your lucky! i remember just once seeing flash paper in a magic shop but the store closed down. So with what you state i take it that the substance is now illegal right? Darn! but still i just wanted to know how to make it so ican show the real deal on that short video we are ganna make instead of adobeing it :( so i take it there is no or little chance that i will find this info anywhere eh? and i suppose u cant just buy the ingredients (as it was stated is hard to get) and just mix them up (as far as i know mixing chemicals without knowing the true danger is a death warrnt in itself) in a bucket or something Maverick423 18:13, 6 February 2007 (UTC)

Yep, if you read nitrocellulose (redirect from gun cotton) you'll find it explains in some detail how to make it.. including "...very careful preparation of the cotton: unless it was very well cleaned and dried, it was liable to explode spontaneously.." - so maybe it's for the best the ingrediants are hard to get hold of (hopefully).87.102.13.26 18:25, 6 February 2007 (UTC)

so its an extreamly unstable compound then... i take it you will need face masks and some sort of protection as a precaution from a accidental explosion then. hmmm but cotton is acctually used? thats intresting. Maverick423 18:32, 6 February 2007 (UTC)

Explosion is not the problem during production, but a boiling burning nitic acid if the reaction gets a little bit hasty.--Stone 18:34, 6 February 2007 (UTC)
The pure compound is quite stable on it's own (in the absence of sparks etc) - but impurities can make the gun cotton unstable. (I think)87.102.13.26 18:44, 6 February 2007 (UTC)
Why are they so distrusting of young folks in the making of explosive and incendiary materials? Oh yeah, now I remember my experiences. The book says make a gram of something and note that it explodes with a pop. I thought that an ounce would be more fun, and it went off with a boom and I was lucky not to lose an eye or fingers. A friend burned down his grandmothers porch (wise enough to take his experiment outside). Fifty or 100 years ago was the golden age of chemistry sets, when the home experimenter could buy literally and reagent. Now kids are taught to be afraid of chemistry and science, except for maybe somesolution changing color. Edison 18:39, 6 February 2007 (UTC)
20 years ago I bought a winchester of 98% sulphuric and over a litre of ~70% nitric from a 'pharmacist' - don't think I could do that now.87.102.13.26 18:44, 6 February 2007 (UTC)

ehhg tell me bout it i bought a chemistry set with NaCl as the main compound it was very very "cool" at that time now im angered that everyone that was around 20 40 years before i was born had so much more stuff to play with in their chemistry set. and edison is right! in schools they always say (becareful around the lab if you get any liquid on you tell us so we can wash it off even if its just water) i mean comeon thats enough to cause a kid to crap his pants if he gets anything on him. 20 years have gone by for me and the only chemical reactions i have seen is a barbque pit lighting up, fireworks, and water evaporaiting. (of course i seen a bit more but u get my point) Maverick423 18:50, 6 February 2007 (UTC)

There are online stores that sell flash paper -- mostly magic shops and theatrical suppliers. One is at http://www.theatrefx.com/moreinfo_fp01_flash_paper.html -- this is NOT a recommendation, just a site I found by Googling "flash paper." For anyone bemoaning the lack of fun explosive chemistry sets for kids, there's an interesting article from Wired at http://www.wired.com/wired/archive/14.06/chemistry.html.

[edit] God and science

Has science disproved God? Darkhorse06 18:00, 6 February 2007 (UTC)

Science can only disproof things which are bound to the laws of physic!--Stone 18:03, 6 February 2007 (UTC)

you know i always wondered that however i remember one thing

science still hasnt proven or showed how ,that pleage that moses used to kill all the first borns, occored or anything to explain the weird reactions that the pleage had on only targeting the first born and passing over the ones that had blood on the doors. (even though im a man of science seeing things that cant be explained makes me just wonder) Maverick423 18:22, 6 February 2007 (UTC)

Plagues of Egypt#Historicity incidentally. Also, your last sentence suggests you witnessed the plagues yourself. How old are you? Skittle 19:55, 6 February 2007 (UTC)
The existence of an omnipotent deity is (arguably) not within the realm of scientific discovery. Also, from at least some point of view, science cannot "prove" anything to an ultimate degree of certainty. It can only make predictions based upon past observations. These predictions become the laws and theories of science that we use. Theories in themselves can easily be disproved; in principle it takes only one repeatable experiment that disagrees with the theory. We sometimes call theories "laws" when they have been proven time and time again. Science could only "disprove" God if the existence of God made certain assertions or predictions that experiment and observation disagrees with. Whether that is the case depends largely on exactly what a person thinks a belief in God entails.
Can science disprove that some intelligence caused everything to be? Not really. Taking big bang theory as an example, we cannot answer what there was "before" the big bang, because, in the paraphrased words of Hawking, "that's like asking what is north of the north pole". Science is generally limited to what we can observe and measure somehow. If we cannot observe a god and quantify it, there's very little science can do to prove or disprove its existence. The very basic question is really a philosophical one, so you'll see lots of opinions. Now, as to individual claims that come along with many peoples' ideas of God and creation, those may be answered on a case-by-case basis. -- mattb @ 2007-02-06T19:47Z

ah sorry about that i didnt intend to make it come out that way. i ment that seeing as how science hasnt figured out what caused it; that gives me doubts about science being correct on evolution and stuff like that. thanks for the link i will start reading it right now. Maverick423 20:23, 6 February 2007 (UTC)

Evolution is a pretty sound theory that is observable on the small scale. The concepts of mutation, variation, natural selection and adaptation can all be observed in a reproducable laboratory environment. People who claim that evolution is mere postulation are usually under one or more misconceptions. Perhaps it's abiogenesis that you doubt? -- mattb @ 2007-02-06T20:36Z
P.S. - If you want to get into the philosophy aspect of this question, Existence of God does a nice job in covering the high points. -- mattb @ 2007-02-06T20:20Z
Science is not complete and doesn't have all the answers at this time (or even ever for some things), which can be a very unsettling idea. It doesn't mean that what it has figured out is not well established. And you also seem unsettled by a distinction between how vs what. People long knew that things fell when dropped even without knowing what was going on. Even long before anyone had a clue how gravity actually "works", we had the law of gravitational attraction. DMacks 20:41, 6 February 2007 (UTC)

Yes i admit im caught inbetween both these issues. the fact that both of them seem real at times is just confusing. god does this and that one person caught in the middle of it is spared while everyone around him dies. science cant explain what happened. yet... it has rumors of what might of happened but they cant confirm it. a higher being? God? or just a series of events that led to the persons survival while everyone else died. like i said its not a very good position to be in when your stuck in the middle. Maverick423 20:59, 6 February 2007 (UTC)

Yes, the point about completeness is worth remembering. The best scientific theories stand only because nothing has yet proven them to be incorrect. Some of today's theories may be a footnote in tomorrow's science history books. A fun example is that of quantum mechanics (QM) and general relativity (GR), the two principle modern theories of "almost everything". The former describes three of the four fundamental interactions observed in nature (electromagnetism, strong and weak nuclear forces) while the former describes the fourth (gravitation). Both theories are widely accepted and are backed by plenty of experimental evidence. The theories also contradict one another; they cannot both be correct and we're not yet sure how to reconcile them (or whether they really can be reconciled).
I think QM in particular presents a more interesting case. Even if you know everything QM can tell you about a system (let's call it a "wavefunction"), you cannot predict with certainty what the result of a given measurement on that system will be, only probability. This presents an enormous philosophical debate: is quantum mechanics incomplete, and there is some other unknown factor outside QM that determines the characteristics of a system (the so-called realist view) or is there something fundamental about the act of measurement that causes a system to suddenly have a measurable parameter? Some of the greatest human minds have grappled with this and been unable to agree upon an answer yet. Science is constantly evolving and along with it our understanding of the universe; it's hard to say whether everything can be explained with science (another philosophical debate).
Anyway, I wouldn't feel too bad about being a little bewildered by all this. Nobody even remotely can provide all the answers (save for, perhaps, an omnipotent creature, if you believe in such a thing). Perhaps you'll find some solace in The Answer to Life, the Universe, and Everything. -- mattb @ 2007-02-06T21:02Z

Heh thanks much you been quite the help mattb. Maverick423 21:17, 6 February 2007 (UTC)

I suggest reading God, the Failed Hypothesis: How Science Shows That God Does Not Exist for a talk about controlled experiments in search of God. [Mac Davis] 72.188.92.255 21:34, 6 February 2007 (UTC)
It really depends on what you mean, if you mean. God does not 'exist' if you think of the bible or other such documents as theories, then yes, god is disproved, because a theory must be falsified (have proof). While personally I don't believe in a divine being(s), You really should do your own reading. Religion, god, etc, are all taken in faith, and thus, it's something personal, and something you much answer for yourself; does god exist?--HoneymaneHeghlu meH QaQ jajvam 23:18, 6 February 2007 (UTC)
Mattb was right in saying that science, or at least empirical science, only works through present and observable events. While it's true that you can't absolutely prove the 10 plagues in Egypt because they're not repeatable events, evolution too falls upon the same rut. You cannot do evolution in a lab, (Although I have heard of scientists have claimed to do this by creating amino acids, which are not life, but merely the building blocks of life.) Evolution also has a lot of history that lacks evidence (ever heard of missing links?), putting both viewpoints in a state of controversy. This is because you can never prove through [empirical] science whether if God existed or not, or if evolution is fact or not because history is not repeatable through experiments (although you can reconstruct a past). Does that answer your question?
So what, does that mean we can rely on nothing now? Is everything just theory, and no one can ever be sure? Well, if that was true, then we can never prove anything in court, because all events took place in the past. But in a court they have what's called proof beyond a reasonable doubt (or if you want to do some further reading, read prima facie), which tells that while there is not enough evidence to absolutely prove something, it is enough to hold up in a court of law. However, there are a lot of arguments for both sides.
Those who support evolution quote of differentiation within species through allopatric speciation; those who support creationism (God created the world) ask why punctuated equilibrium relies on evidence of 'no change in species' to support that 'species do change'. Those who support God's existence quote first hand accounts of answers to prayer; those who reject this belief ask why can't people believe that was merely a 'freak accident'. Basically, both sides say that they're right. Yet what it really boils down to is not "which argument is right", but "which argument is more logical". Therefore, the court of law illustration is probably not the best one for this case, but a better one may be is two kids arguing about their past. So the answer is no, science cannot disprove God.
I hope I have answered your question thoroughly enough. For anyone who wants to know, I believe that God's existence is more logical. However, I have tried to provide sufficient evidence for both arguments, but if you do find any flaws to my answer, tell me, I'm not perfect. (As entertaining is the thought of having God answer questions on the Reference Desk, Bible text indicates Jesus wants you to receive Him personally [3]. :) ) I hope this helps, Darkhorse.--JDitto (talk to me!) 03:36, 7 February 2007 (UTC)
Not meaning any disrespect, but your post indicates that you yourself are under several common misconceptions about what evolution is and what it asserts. Evolution and abiogenesis are different concepts, as I indicated earlier. It's untrue that evolution cannot be observed; it has been observed on many scales, from viruses to fruit flies. Further, you seem to be treading the line of misunderstanding what "theory" means in the scientific sense.
Please don't take this as an attack, I mean no ill will whatsoever. It's just that it really helps to be as informed as possible when discussing this subject. -- mattb @ 2007-02-07T05:24Z
It is rather natural for people to latch onto the idea that we can use reason and logic to decide what is true. Through millions of years of biological evolution, our brains have been crafted to do a good job of making such decisions about questions like: "Who has more bananas, Og or Urk?" Philosophers such as Wittgenstein have made the point that we easily get ourselves in trouble by using our intuitions, logic and reason to deal with abstract ideas that exist beyond the reach of objectively verifiable data. Proof is just an argument that other people accept. Carl Sagan suggested that we should all practice skepticism and apply this rule of thumb: "Extraordinary claims require extraordinary evidence." --JWSchmidt 05:18, 7 February 2007 (UTC)
Here's another philisophy: we can always use reason and logic to decide "truth". The question of God however, falls outside of truth. truth has rules. Omnipotence has no rules and is therefore not subject to truth. The existence of God is a claim of Faith, not a claim of Truth. --Tbeatty 05:26, 7 February 2007 (UTC)
To be valid, scientific theories have to be testable. The test may not be possible technologically, but it must be conceivable and not contradict the theory it is trying to prove. For example, the Theory of Relativity postulated certain relationships velocity, mass, time, energy and the speed of light. Actual measurements were then compared to the theory, which corroborated it. It is not "proved" but the lack of disprrof as well as it's ability to predict future events makes it science. In this context, the existence of an omnipotent being is non-testable because the outcome will be whatever the omnipotent being chooses (the beauty of being omnipotent). This simply moves the "question of God" out from being a question of Science to a question of Faith. They are complementary questions, not competing ones. --Tbeatty 05:26, 7 February 2007 (UTC)
My own personal observation about evolution is that it is currently mostly an observable. Certainly there are genetic inheritance theories which have both testable, predictive value. But a lot of evolution is simply an obervable of current events. Much like the knowledge that an apple will fall from a tree and it occured long before Newton had his theory. Evolution has almost no predicitve value. Natural Selection is an obervable, not a theory. Sceintifically, we have no idea why certain species were "selected." We simply rationalize what is here vs. what is not but we can't predict what a future adaptation will be. What will the next predator on the Serengeti look like? What will the prey look like? We use the observables of extinct species and non-extinct species to try to identify what the distinction was, but we really have no way to predict what future species will out compete its neighbors. We only look in hindsight. If Hyenas live while Lions die we will look at distincitons and make broad claims. If lions live and hyenas die, we will rationalize their survivor traits. But we currently can't predict what Natural Selection means and what survivor traits are, only that some survive and some don't. We make up the rhyme and reason to fit the facts. --Tbeatty 05:26, 7 February 2007 (UTC)
Nicely put. -- mattb @ 2007-02-07T05:45Z
Richard Dawkins' God Delusion has a chapter on why God is improbable (i.e. highly unlikely) and points out the fallacy in assuming that because two things cannot be proved 100% they must be treated equally. For example, noone can prove that fairies aren't pushing things down to cause gravity, but it's very unlikely, if it had been written down in a book nearly 2000 years ago people probably would believe it though! When it comes to something like the biblical plagues mentioned above. The statements made show the problems in disproving God. The Bible can make a statement about what God or Jesus did which is scientifically impossible. A sceptic might say science has proved this is impossible and therefore disproved God as described in the bible. A believer might say science can't explain this, therefore science is wrong (taking the truth of the bible as given). So how is it possible to prove or disprove God in these circumstances? But to me the likelihood of some supernatural being creating things seems much more unlikely than any scientific explanantion, when most of the evidence for God seems to be an old book, tradition and the fact that science isn't 100% perfect.137.138.46.155 08:17, 7 February 2007 (UTC)

^^^ This made me remember about a old show i saw once. in it they brought up a question that stated something like this " was it god that created man or man that created god?" it does make me wonder like IP dude stated above all the proof of god is an old book. man could of created god to belive in something that something else something greater is out there. they might of used this as a way to explain how they came to be and now that science has found the truth they refuse to belive it because man is stubborn. BUT like i stated before i still have doubts about it but well we can only move forward and see what comes out of it Maverick423 14:34, 7 February 2007 (UTC)

A lot of people seem to be ignoring the fact that the Judeo-Christian view of God isn't the only one. -- mattb @ 2007-02-07T17:31Z

[edit] Pet rats and Guinea pigs

What are the chief behavioral differences between pet rats and guinea pigs? --Andreas Rejbrand 21:22, 6 February 2007 (UTC)

[edit] Search engine syntax

If I want to look for Martin Luther rather than Martin Luther King, what should I do? Let's say I want to list all ML-only, MLK-only and ML+MLK web pages, how do I do it? I just want to know it this is possible. This question is not specific to any search engine or database service (e.g., Internet and other proprietary databases). -- Toytoy 21:23, 6 February 2007 (UTC)

"-King" without the quotes should be what you're looking for. Most search engines will exclude results containing a word with a minus in front of it. Additionally, putting a plus sign in front of a word will force results to contain it. You can also force the exact phrase to be searched for by putting it in quotes, as in "Martin Luther", but that may still pull up results about Martin Luther King if king has not been explicitly excluded. Cyraan 22:04, 6 February 2007 (UTC)
-King or more specifically -"King Jr." will typically exclude all references to the man who "had a dream". The easiest way to look only for King is to search for, in quotes, "Martin Luther King". This will require "King" to be next to Martin Luther as a complete phrase. To get both, just search for "Martin Luther", but be aware that different search engines will optimize this differently (Google will return primarily hits about Martin Luther, not MLK, because of the way it indexes terms). --24.147.86.187 23:51, 6 February 2007 (UTC)

It is possible to retrive "Martin Luther"-only entries: "martin luther" AND NOT "martin luther king".

-king, so search for Martin Luther -King, and in the unlikely event you get results for people names Martin, and people named Luther, use "Martin Luther" -king. On almost all search engines, putting a minus in front of a word will force it to exclude results that contain that word. Cyraan 05:00, 7 February 2007 (UTC)

How do I retrive "Martin Luther King"-only entries? "martin luther king" BUT NOT "martin luther" will return nothing! I mean only "King" can go after "Martin Luther". -- Toytoy 04:52, 7 February 2007 (UTC)

Put it in quotes, Martin Luther King will search for all of the words, no matter their placement on the page or order, putting it in quotes like this: "Martin Luther King" forces it to search for only that phrase, and only in that word order. Cyraan 05:00, 7 February 2007 (UTC)
No "Martin Luther King" would retrieve entries with both "Martin Luther King" AND "Martin Luther". Example: "In 2000 B.C., Martin Luther King drove a second-hand Toyota to Nepal to visit Martin Luther." -- Toytoy 05:04, 7 February 2007 (UTC)
Hmm, what search engine are you using? "Martin Luther King" on google doesn't turn up any results on Martin Luther for at least the first 5 pages (as far as I looked). On any engine I've used, using quotes forces only results that match the quoted phrase exactly to show up, if it doesnt have "Martin Luther King" in exactly that order, and containing every word, its not shown. "Martin Luther" might pull up both because both would match the quoted criteria, but thats where -king would come in. Cyraan 05:05, 7 February 2007 (UTC)
I think the question is about pages that have both the strings "Martin Luther King" and "Martin Luther <X>" where <X> is anything other than "King". I think the answer is "you can't exclude these" (when looking for "Martin Luther King") and you probably don't want to, either. Searching for "Martin Luther King" will find pages that have this exact string on them, as well as pages that have this string AND other occurrences of "Martin Luther not King" and "Martin not Luther King" and "not Martin Luther King" and "not Martin Luther King", but all of them will have at least one occurrence of "Martin Luther King". -- Rick Block (talk) 05:37, 7 February 2007 (UTC)

[edit] physics books

What is the best physics books escpecially in quantum physics for engineering ascpects?84.36.150.67 22:57, 6 February 2007 (UTC)mostafa elashram

Best is certainly a superlative. What criteria would you have us consider? If you're interested in QM (I'm assuming you don't yet have a solid grounding in the theory), a good introductory book is "Introduction to Quantum Mechanics" by David Griffiths. -- mattb @ 2007-02-07T03:11Z
P.S. - What field of engineering are we talking about? I'm a semiconductor person on the engineering side, but I can't think of too many other non-physicists outside the realm of semiconductors that would need to use QM regularly... Nuclear engineering, perhaps? -- mattb @ 2007-02-07T03:18Z


Material Sceintists working on solids (i.e. superconductors, carbon tubes, some polymers) use QM quite regularly. Optical engineers and people working on lasers use QM quite regularly. --Tbeatty 06:29, 8 February 2007 (UTC)
Optical engineers might as well be physicists... -- mattb @ 2007-02-08T17:19Z