Wikipedia:Reference desk/Archives/Science/2007 July 9

Science desk
< July 8	<< Jun | July | Aug >>	July 10 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

July 9

Political views of Scientists

Obviously scientists (defining scientist however you want) have a broad range of political beliefs. However taking all scientists, how do you think their views compare to the general public in their country. ie More conservative or liberal in social policy?, more left wing or right wing economically? More religious or aethiest than the general public? etc.

Over the earth or over first world countries?

I'll presume you mean the U.S. and PhD scientists. More liberal in social policy. More capitalist economically. More religious than the general public. --Tbeatty 01:57, 9 July 2007 (UTC)

Presume the U.S if thats where you are Willy turner 02:19, 9 July 2007 (UTC)

Of course you should use a scientific approach regarding the answer to this question! Note the distinction between correlation and causation. Also note the exceptions to the general trends. And finally, evaluate whether your initial criteria are valid to begin with (is "liberal/conservative" a good way to measure political affiliation and belief?) Nimur 02:03, 9 July 2007 (UTC)

liberal/conservative is one way. feel free to answer the question with regards to any other measure of political beliefs you like Willy turner 02:19, 9 July 2007 (UTC)

I would vote for less religious than the general public. More sceptical of everything. Aaadddaaammm 02:05, 9 July 2007 (UTC)

Surveys support your view, with practitioners in the "hard sciences" being far less religious than the claims of (at least) the American public at large.

Atlant 16:49, 9 July 2007 (UTC)

Thats what i would have thought. Willy turner 02:08, 9 July 2007 (UTC)

In fact, it is fairly well established that US scientists are much less religious than the general US public, and that this difference becomes dramatic if one restricts the comparison to those top scientists that are members of the National Academy of Science. 169.230.94.28 02:17, 9 July 2007 (UTC)

One thing that is distinctive about good scientists is that they have open minds until they see proof. This tends to make conventional political distinctions hard for them to make. Democrat/Republican, Left wing/Right wing...these are statements of a belief in a bundle of policies. To pick two issues at random - traditionally, in the USA, Republicans are anti-abortion and pro-guns - Democrats are pro-abortion and anti-guns. A scientist can't simply fall into one demographic or the other. A scientist has to examine the issues - and may well decide that they are pro-abortion and pro-guns (for example). Taken over dozens of issues, this will result in someone who probably sides mostly with the views of one side - but may be very extreme on the opposite side for other views. On the whole, I think most scientists tend to be "left of center" in a majority of their views, wildly leftist on others and wildly rightist on yet others. The whole idea of "joining a club and mindlessly promoting all of their views" is an anathema to most of us. SteveBaker 02:53, 9 July 2007 (UTC)

Spot on, SteveBaker. Well summarized. Nimur 18:45, 9 July 2007 (UTC)

If the interface of science and politics is something that interests you, Chris Mooney's The Republican War on Science is an essential read (or just wait for the upcoming documentary). As SteveBaker says, scientists tend to be less ideological than the average member of the electorate, and thus harder to pigeonhole in such broad strokes. So while scientists, as a group, are probably on average somewhere left-of-centre on their personal politics, the perception as scientists as overwhelmingly and actively liberal is no more than a political tactic. Indeed, painting politically unconvenient research as junk science and policy friendly research (usually from industry) as sound science has become remarkable common in the US, and is extensively by the Bush administration to justify forming policy against the scientific consensus. Indeed Karl Rove sums this up best with his definition of a Democrat as, "somebody with a doctorate." Rockpocket 03:26, 9 July 2007 (UTC)

On the other hand Newt Gingrich is an advocate of increased federal funding for basic science research. I have heard him on NPR and he sounds genuine about this issue. Rove really said that quote? :eyes rolling: David D. (Talk) 03:32, 9 July 2007 (UTC)

A bit of an aside, but an interesting one all the same, Mooney addresses Gingrich in Chapter 5 and acknowledges,

... Gingrich presents a condundrum. On one hand [he] presided over an era of stunning congressional science abuse. And yet Gingrich is no anti-intellectual rube. Far from it: he holds a PhD, taught environmental studies and has a reputation as a science fiction fan and ardent technophile.

Indeed since leaving congress he has actually proposed tripling NSF funding. But despite that he set the stage for the politicization of science in modern US politics by dismantling the Office of Technology Assessment, which used to provide objective analysis of scientific and technical issues for Congress. The OTA was a agency of stellar international repute. When it was trashed Lord Kennet commented that "the leading technological state in the world should have abolished its own main means of democratic assessment left us [The British] aghast." So why did Gingrich dismantle it? So he could bring in his own "experts" that provided the requisite analysis that backed up their preferred policy. For example, in 1995 the Gingrich Congress heard "scientific integrity" hearings into whether CFC's were linked to stratospheric ozone depletion. By then the scientific consensus was all but unanimous in accepting this (infact later that year Mario Molina and Sherwood Rowland received the Nobel Prize for their work in demonstrating it). Who did Gingrich bring in to provide "objective analysis of scientific and technical issues" in place of the OTA? Fred Singer and Sallie Baliunas, two of the few high profile skepticsof global warming. So Gingrich's Congress was pretty much the architect of a free market for science expertise: they demanded experts that told them what they wanted to hear and the OTA wouldn't supply that, so they found scientists who would. The result, which persists to today according to William Schlesinger, is that politicians "go to the table with their hired guns and beat on each other for a while, and there is never an agreement and nothing happens - and CO2 continues to rise." Rockpocket 07:06, 9 July 2007 (UTC)

I think you need to define what religious is. I think if you define it as regularly attending church, you'll find they are more religious. This is a demographic thing. Most likely educated, upper middle class, white male with 2.5 kids, etc, etc. This screams regular churchgoer without ascribing to any particular belief. There is more to religion than creationism and there are religions that don't adherently preach creationism like some fundamentalist churches. In fact, Vatican observatories are some of the most respected in the world and the chruch spends a large amount of money on scientific research. --Tbeatty 03:51, 9 July 2007 (UTC)

And you present this theory, in the face of actual studies to the contrary quoted above, based on which reliable sources? —Preceding unsigned comment added by 169.230.94.28 (talk • contribs)

And what studies were those? Religious is more than a belief in God. Also, the study comparing scientists belief over time when both the term "scientist" and the nature of science has changed so drastically is not quite valid, is it? Certainly not as a an answer to the question comparing scientists to the general population. --Tbeatty 04:24, 9 July 2007 (UTC)

Since you appear to be from the US, I was assuming that you were aware that around 44% of the US public claim to attend church regularly, according to many polls like this one [1]. In the above survey, 72.2% of top scientists professed "personal disbelief" in God , and another 20.8% professed "doubt or agnosticism". For these scientists to be "more religious" than the general public, using the regular-churchgoing criterion that you suggest, would require that all the believers, all the agnostics and doubters, and almost a quarter of the outright disbelievers would have to attend church regularly. Is this really what you believe? 169.230.94.28 05:26, 9 July 2007 (UTC)

Very late I know but in case someone revisits this, I just remembered I forgot to post a message. It seems to me you're saying because A is correlated with X and X is correlated with B then A must be correlated with B. Since I believe you're one of the people who screams at e.g. environmentalists who do this (quite rightly) I'm surprised to find you doing it yourself. The fact that scientists may be (haven't see the stats altho it sounds like it might be right in the US) more likely to be upper middle class, white male, 2.5 kids etc people and that upper middle class, white male, 2.5 kids etc people are more likely to be regular church goes does not imply that scientists are more likely to be regular churchgoes. Remember that scientists are only a very small percentage of this population. It wouldn't surprise me that people in the US who define themselves as atheists generally fit that demographic. Are you going to tell me they're regular churchgoes too?

More importantly perhaps, it seems to me you're using an incredibly bad definition of 'religious'. While the question may have been ill-defined, it seems to me that if someone regular attends church but does not believe in God or spiritualism or the afterlife or any of the other stuff normally associated with religion, then this person could harly be called religious. Someone may attend church for a variety of reasons. For community & social reasons, to accompany a spouse, because they feel it's good for the kids as a way to learn ethics and other reasons etc etc. But someone who attends churchs for these reasons can hardly be called 'religious' IMHO. Being religious implies that someone believes in some of the stuff that defines said religion (whatever that religion may be) and in the case of Christianity in particular, would believe attending church is something God expects from his/her 'children'.

BTW are you sure white & male are important for regular church goers? While I don't know much about US demographics, from what I do know it would seem to me that black people in general are more likely to be regular church goers and that females are also more likely then males...

Nil Einne 21:09, 4 August 2007 (UTC)

Creationism Questions

Firstly, how do creationists explain how plants and fungi and protists (and everything else alive at that time) survived the flood? There are indeed many living things that would survive a forty-day flood, but there are some that would not. The bible only mentions animals going on the ark. Also, does anyone recall whether the bible mentions the depth of the water? This would have a large impact on the survival of photosynthetic creatures.

Secondly, I have studied the "exact proportions" (according to the bible) of the ark that god commanded Noah to build, and I doubt that two of every species of animal would fit on something of that size.138.87.213.224 02:20, 9 July 2007 (UTC)

The first one could be answered by an evolutionist too- what we see now are the surviving plants. The second one would probably get you two answers- an apologist saying you shouldn't take it literally, and someone who's dead set in their ways telling you that it was a miracle, or some such --L^augh! 02:32, 9 July 2007 (UTC)

Your questions are addressed at Noah's Ark#Biblical literalism and the Ark. Specifically, the apparent conundrum is usually explained by the fact that the Ark contained representatives of "created kinds" rather than species known today. This belief has spawned the pseudoscientific discipline known as "Baraminology". Rockpocket 02:33, 9 July 2007 (UTC)

Asking the science desk how creationists explain this is not likely to end well! Since creationism is about as far from science as it's possible to get - it's unlikely that many of them are here to answer your question. It goes deeper if you want to get picky - how do you feed all of those animals for 40 days? Particularly since a good fraction of them only eat other animals. Where did the water come from? Where did it go to? How come we don't see any evidence of a world-wide layer of sediment? When the dove returns to Noah with the olive branch - we have to ask ourselves what Olive trees had survived 40 days underwater. If it rained freshwater - then the level of dilution of the oceans required in order to get the water depth up to the top of Mt.Everest would kill most saltwater plants and animals - if it rained saltwater - then ditto for freshwater lifeforms. The questions and obstacles that a sceptical mind can throw into the path of this rather nice childrens' story are truly endless. However, if you believe in a being with literally unlimited powers - then no story is falsifiable. All a creationist has to say is "God arranged it so it all worked out using his magical abilities" - and you can't take the argument any further. Any hypothesis that includes such a being is unfalsifiable - and the whole of science, engineering, history and anything else humans have done becomes irrelevent. SteveBaker 02:39, 9 July 2007 (UTC)

This is the nature of faith. God can certainly fit two of every creature on the Ark if you have faith. The fact that YOU can't fit two of every creature in the ark answers another question :). Ask a scientist how life was created from molecules and amino acids and the answer will be a faith based answer of sorts saying that science can answer that question someday. Science answers a lot of questions. And with each new answer comes two new questions. Science doesn't diminish the concept of God, rather the complexity that science reveals actually makes God more intricate. Think of what science has done to the scale of God. In about 300 years, God has gone from the creator of 1 planet at the center of the Universe to the creator of a Universe with billions of galaxies that contain billions of stars. The universe has expanded from 8 light-minutes to 10 billion light years. God has gone from Earth-Air-Fire-Water to molecules, atoms, quarks and strings. And just think of the rules system he has created that we are just unravelling. --Tbeatty 04:04, 9 July 2007 (UTC)

You bring up an excellent point, which brings up one of my beefs with organized religions; they are still struggling with "science", ca. like 1920. As a "seeker after truth" in whatever form it may come, I'm disappointed that they haven't got much to say regarding quantum mechanics, DNA, the Big Bang, dark energy and dark matter, the expanding cosmos, and the now burgeoning catalog of extrasolar planets. Gzuckier 18:48, 9 July 2007 (UTC)

Here is a pretty decent attempt at a literalist justification. But for the real creationist student, what the (amateur) reviewers are calling a "tour de force" that answers "the folly of Ark critics, many with science doctorates" and puts the "Darwinian fundamentalists" in their place [2], may I present to you: Noah's Ark: A Feasibility Study. Rockpocket 04:19, 9 July 2007 (UTC)

The Bible neglects to mention that God made all the animals 2 inches tall and miraculous made them not need to eat or poop for 40 days. If you choose faith, that's about as good an answer as any other. There is no scientific basis for understanding the ark, and it's not really reasonable to expect one. Filling in the details is basically always going to be an exercise in creative writing. Dragons flight 04:37, 9 July 2007 (UTC)

If we are to believe that God created the entirety of all that is in six days, then is it really that much of a stretch to believe that he could somehow fit 2 of every animal onto a ship for 40 days? --Kurt Shaped Box 05:17, 9 July 2007 (UTC)

I'm not really interested in this question but just wanted to point out that it was only the unclean animals that went in by twos. The clean animals and the birds got to be collected in sevens. (Genesis 7:2–3.) Not a lot of people know that.--Shantavira|^{feed me} 07:33, 9 July 2007 (UTC)

"God can certainly fit two of every creature on the Ark if you have faith." How? does he make the animals smaller, the ark bigger, or what? 80.169.64.22 18:12, 9 July 2007 (UTC)

Yes, yes and yes. ;) --Kurt Shaped Box 18:17, 9 July 2007 (UTC)

If you want to start nitpicking biblical literalism, Project Gutenberg's King James Bible is a good free free electronic reference. There are also many many many other bibles on Project Gutenberg for your viewing and comparison. With a modern computer, diff, and wiki technology, I think there's a lot of interesting details you can come up with in comparative biblical study. Nimur 18:54, 9 July 2007 (UTC)

I tend to think there really was a great flood, but not one that covered "all the Earth". After all, how would they have known it covered all the Earth, as they could only see for a few miles in each direction ? The giant flood which formed the Black Sea is a good candidate. The ark may have indeed contained a few farm animals useful to restart life once they found their way to dry land, but certainly not every animal, much less every life form on Earth. See Black Sea deluge theory. StuRat 06:35, 10 July 2007 (UTC)

That's a fine theory - and I'm pretty sure that the same Black Sea event is what several religions are talking about in their flood stories too. The impossibility of a truly global flood - combined with the fact that all of the animals from other continents would not be needed if the flood was a purely local event suggest that local flooding is a much more possible thing. If Noah just needed sets of the animals he knew about from (say) 30 miles around his home - then perhaps a couple of dozen species might well have done the job and a boat that could truly have been built in those times could have contained the animals plus sufficient supplies for a month or two at sea. But from a religious perspective, the very moment you let yourself start modifying what the bible says - you've left yourself open to the question of whether you modified the right words. An alternative view is that Noah "SAID" all of these things happened to him - when in reality they didn't - you can come up with a bunch of ways to change the story and make it work - the only problem with most bible stories is when we're expected to take them literally. A few years ago, I actually sat down and read the King James bible from cover to cover - and as a work of fiction, it's really not all that bad. There are lots of plot holes and inconsistancies - and it's not exactly compelling literature the whole way through - but if you read it as if it were a sci-fi book - there are some good short stories tucked away in there. SteveBaker 00:22, 11 July 2007 (UTC)

I am an undergraduate who does work in neurogenetics under a fairly prominent PI and am familiar with basic introductory college-level evolutionary biology, down to the genetic and molecular level. As far as I know, every claim made by creationists has been debunked, completely, by evolutionary biology's findings; more scientific articles should be linked to in the evolutionary biology Wikipedia articles to further bolster the strength of the articles on Wikipedia. There also needs to be a better explanation made available for those who do not know about the differences between theories in the philosophical sense and theories in the scientific sense - a theory is an assertion that is supported by factual observations, analogous to a 'fact' in the philosophical sense. Theories have room to change if there is new observation that contradicts what is asserted by the theory.

Religion is completely irrelevant in any scientific arena, especially when it makes unsupported assertions that are contradicted by what scientists have found. 70.187.214.119 00:35, 14 July 2007 (UTC)

Spring Flowers

Spring flowers from my garden

I actually am seeking a peer picture review in hopes of finding someone who knows what this flower is. I planted it last summer but for the life of me cannot remember what its name. I've been told that it's some type of carnation but I'm not sure. I think it's a good photo to be included in an article once I find out what the flower's name is. - AutoGyro 02:34, 9 July 2007 (UTC)

Comments:

• Looks like Sweet William to me. David D. (Talk) 03:35, 9 July 2007 (UTC)

(why is this transcluded onto the ref desk from Picture peer review?)

• Yup, go ahead, rename as "Sweet William Dwarf" (reference: [3]) and add it to the article. Bendž|Ť 17:52, 9 July 2007 (UTC)

100cc,250cc,500cc

What does CC imply in the knowledge of bikes?

Cubic centimeters of cylinder displacement.169.230.94.28 04:24, 9 July 2007 (UTC)

A cubic centimeter is .001 liters (1 milliliter). A 500cc bike is a 0.5 litre engine to compare it to car engines standard sizing. --Tbeatty 04:37, 9 July 2007 (UTC)

Argh, I was beaten to it! While we're on the topic, what're generally suggested usage ones? I know I've heard that generally beginners should have less than 150cc, but that more experienced riders will want more, but what're the guidelines on that? --L^augh! 04:40, 9 July 2007 (UTC)

1 cubic centimetre (of volume) is the definition of 1 milliliter.

or

1 cubic decimetre (of volume) is the definition of 1 litre.

202.168.50.40 04:56, 9 July 2007 (UTC)

It is a general understanding that higher the CC, more powerful the engine is. In India, most of the bikes are of 100cc and that is what the beginners use. I don't think there are any guidelines for this. It is just that beginners may not be able to handle something which is very powerful and hence a lower CC is recommended -- WikiCheng | Talk 09:32, 9 July 2007 (UTC)

In most states of the USA, you do not need a special license for bikes with 49cc or smaller engines. Larger than that requires a motorcycle permit and/or a vehicle driver's license (with regional variation from state to state). Nimur 18:57, 9 July 2007 (UTC)

In New Zealand you can drive a speed restricted (50 km/h) 50cc with an engine output of 2KW or under scooter (moped) on any license (including car) [4]. People on a learner's or restricted motorcycle license can only drive a 250cc or under motorcycle [5]. Nil Einne 23:19, 10 July 2007 (UTC)

Tox Screens

What are tox screens (and what is the appropriate article)? They mention them frequently in CSI and Scrubs. ALTON .ıl 05:50, 9 July 2007 (UTC)

Forensic toxicology may be what you're looking for. --Kurt Shaped Box 05:55, 9 July 2007 (UTC)

I believe that means screening (testing) for the presence of toxic chemicals. StuRat 06:23, 10 July 2007 (UTC)

4-legged insect

we have found a 4-legged insect in our house, it crawled across the floor and entered a reclining chair, we knocked it out and it jumped back in, so it seems to have jumping powers, it does not appear to have wings, the body is small compared to its legs, kind of like a spider, it even crawled like a spider, the color is dark brown and does not seem to have any patterns. if anybody knows of a species like this let me know, i searched on the internet and the best thing i could find goes to biblical references. anyways i appreciate any help anyone might have

thanks, david

Hello David. I'm afraid there are no insects with 4 legs. All insects have 6 legs (one pair per segment). Perhaps your creature has another pair of legs that are much smaller than the others, or that have become adapted to other purposes (See here for example? Though I suppose someone might have pulled one pair of legs off an insect, thereby giving it the appearance of a four legged creature. Rockpocket 07:58, 9 July 2007 (UTC)

A spider which has lost four legs in the gladiatorial pits? Seriously, losing half its legs sounds a trifle excessive, but when I lived near a forest I would regularly encounter insects and spiders missing one or two limbs. -Eldereft 08:06, 9 July 2007 (UTC)

I once watched a 5-legged spider walking along without obvious difficulty, and wondered: would it travel so well if the lost legs were all on one side (leaving 4+1 rather than 3+2)? —Tamfang 00:23, 10 July 2007 (UTC)

Headcrab? --Reuben 08:33, 9 July 2007 (UTC)

Make sure it is not a tiny intelligent alien. Edison 03:35, 10 July 2007 (UTC)

There is a spider (with 8 legs, of course) which keeps it's legs together in pairs, thus looking like it has 4 legs. I don't recall the name. StuRat 06:14, 10 July 2007 (UTC)

Babies

Chances are it will look something like this. Beyond that is mere speculation. Rockpocket 17:21, 9 July 2007 (UTC)

Hi, my partner and I are curious about what our baby boy or girl will look like.

Myself:

• Born in the Philippines
• 5 Foot 7 Inches
• Black hair
• Dark brown eyes

My Partner:

• Born in Australia
• 5 Foot 4 Inches
• Dark Blonde Hair
• Blue Eyes

I understand that that this is a pretty general question, but if anyone could point me in the direction of some information that may be able to assist. Something we could send in photos.

I look forward to hearing from you.

Dave

This will depend on a lot of factors- what they eat (both your wife and your baby), how long the pregnancy is, if it's your child or not, your bloodlines, which side of the dice some things fall on, and many, many, many obscure genes that govern a lot of things. If you really want pictures, you'll just have to get an ultrasound, or wait. Alternatively, there are some photo booths that will mix your faces together, although it's nowhere near an accurate representation --L^augh! 08:55, 9 July 2007 (UTC)

L - as the question appears to be about genetics and biological inheritance, I don't understand why you start your list with "what they eat". Apart from extreme examples involving drugs or alcohol, how does diet during pregnancy affect the appearance of the baby ? Can you elaborate ? Gandalf61 10:59, 9 July 2007 (UTC)

Diet will affect height - a well-nourished child will grow taller than its identical twin who has been less well fed. DuncanHill 11:28, 9 July 2007 (UTC)

Yep, as well as weight. I imagine a mother that eats more will have a heavier baby, and a baby that eats more than normal will definitely gain weight. --L^augh! 20:49, 9 July 2007 (UTC)

The simple one is eye color. If you have double brown allelles, which is common in that part of the world, your children will have brown eyes as this is dominant, though not necessarily as dark as yours. Hair and skin color are more likely to blend and appear intermediate (though I do know one half-asian woman who is naturally a darkish blonde). Dragons flight 09:10, 9 July 2007 (UTC)

Since you are both relatively short, your children are likely to be so, too. I'd expect girls to be around 5 foot 3 and boys to be around 5 foot 7, with say a 90% chance of being within 6 inches of those marks. Note that this assumes you've both attained your maximum genetic height. If either of you are still growing or had your growth stunted for some reason, then your children should be taller, assuming they reach their maximum genetic height. StuRat 06:02, 10 July 2007 (UTC)

You're ignoring regression to the mean which indicates that shorter-than-average parents will have children taller than them and taller-than-average parents will have children shorter than them. Of course, we need to know more about their genetic subpopulations to really know which category they fall into. Donald Hosek 14:30, 10 July 2007 (UTC)

Weather patterns

What is the Ninio effect (mentioned on the met office as La Nina - with an accent on the second n)? Happens in the Pacific Ocean and affects climate.

El Niño-Southern Oscillation? Someguy1221 15:41, 9 July 2007 (UTC)

La Niña is the opposite of el Niño: the opposite phase of the southern oscillation. --169.230.94.28 17:56, 9 July 2007 (UTC)

Correct, and here's the link: La Niña. StuRat 05:53, 10 July 2007 (UTC)

Thanks for the help, great link, cheers. S

Circuit assistance

Hello Reference Deskers. I'm currently working on a scientific experiment, and I've been placed in charge of circuitry. Unfortunately, I have no electrical engineering background.

Anyway, I have several devices (loads) connected in parallel to a 15VDC power supply. A few of them require the full 15V, but the rest can handle less. Each of them requires a current ranging from 20mA to 300mA.

Now, each of these devices is supposed to light up a green LED if powered on, and a red LED if switched off (or broken). I kind of have an idea of what to do (involves a few transistors and resistors), but I'm wondering what you guys think.

Thanks! — TheKMan 17:51, 9 July 2007 (UTC)

First off, make sure every LED has a current-limiting resistor, especially if you're thinking of driving it with the 15 volts! This can be done, though it will reduce the total life of the LED (usually). LEDs can be driven off much lower voltage. Next, read up on pull-up resistor and pull-down resistor, which you can use to turn the LED "on" or "off" by default. There's ten million ways to arrange the LEDs that would satisfy your needs... let me know if you have specific issues or need detailed schematic assistance. Nimur 18:38, 9 July 2007 (UTC)

I think I would put a low-value resistor in series with the +15 V line to each load, enough to give a drop of a few millivolts when the load is drawing current. The low side of the resistor would go to the input of a comparator. The other input of the comparator would be supplied with a reference voltage from a potential divider fed off the +15 V rail. The output of the comparator would drive the LED. This should be easier for a novice to work with than trying to use individual transistors. Anybody have a simpler solution? --Heron 19:19, 9 July 2007 (UTC)

For clarity, redraw the circuit with multiple load branches and with the switch separate from the load. Naturally it will have to be further elaborated to show the LED circuitry. It concerns me a little that you say the different devices need different voltages. You should be able to have current-operated comparators controlled by the voltage across a relatively small sampling resistor in series with each load as mentioned above. Because the current draws differ so much in each branch , you may need separately adjusted comparator circuits to drive the LEDs. You might consider placing them in the gound (negative) leg of each branch to make the circuitry simpler, so that a chip with multiple comparators might be used more easily than if each sampling resistor was at a different positive potential. Edison 19:40, 9 July 2007 (UTC)

Colour of matters

What's the cause of the colour of matters in microscopic view, and probing it among the particle.Flakture 21:10, 9 July 2007 (UTC)

I believe color at the atomic level is related to the energy of the various electron levels (the s, p, d, and f orbitals within each electron shell). The energy quanta absorbed or given off when changing electrons from one level to another each correspond with a particular frequency and wavelength of light, and hence color. StuRat 05:45, 10 July 2007 (UTC)

It's the same as for other objects you can see with your eyes - couloured lighting and pigments absorbing light. When you magnify a lot you can see coloured diffraction rings or pieces of rainbow around small objects. This is because of the wave nature of light, and that red is longer wavelength than blue. GB 05:51, 10 July 2007 (UTC)

Unless you are talking about color charge in quantum chromodynamics, in which case "color" is just a whimsical metaphor to simplify the bookkeeping. -Eldereft 07:20, 10 July 2007 (UTC)

There does come a point with microscopes of high magnification where the wavelength of visible light is just too long compared to the sizes of things you are looking at. This is why we have electron microscopes to make pictures of the very smallest things. Pictures taken in an electron microscope don't have real "colours" because the very concept of that is meaningless at those small scales. SteveBaker 00:05, 11 July 2007 (UTC)

When Electricity currents in the metals ...

What's the influence of current electricity on the size of metals? and why?Flakture 21:09, 9 July 2007 (UTC)

The size/shape of a block of metal affects current (resistance, actually, and current indirectly). See resistivity for diagrams and equations. Nimur 21:07, 9 July 2007 (UTC)

Many (all???) metal expand when heated. Elctricity passing through any metal other than a superconductor dissipates heat, in an amount equal to the current squared times the resistance. Heat cause the metal to expand, a tendency which is called thermal expansion [6]. The sagging of power lines when they are heavily loaded on a hot day is an important example of this: if they sag too much they touch trees and there is a prolonged outage. (Sag may also involve the matal softening and stretching under the tension due to gravity) Perhaps others can explain why metals expand when heated. Edison 03:34, 10 July 2007 (UTC)

Aluminum Carbonate

A question came up on CarTalk (this past weekend's rerun) about the chemical symbol for Aluminum Carbonate. Tom (and the chemist who had called in with another problem) thought that it was Al₂CO₃, although looking stuff up, it seems to me that it should be Al₂(CO₃)₃. Google searches turn up nothing, nor is there a wikipedia article on this substance (which apparently has some medicinal use). Anyone have the correct answer? Donald Hosek 21:09, 9 July 2007 (UTC)

• Rx for Al₂(CO₃)₃, the apparent correct formula (from what I can find). — Scientizzle 22:20, 9 July 2007 (UTC)

It appears that Aluminium Carbonate may not actually exist - [7]. I googled using the British spelling, which brought up lots of links. DuncanHill 22:28, 9 July 2007 (UTC)

Are you sure they did not mean Lithium carbonate? This is a very powerful psychoactive compound used for treatment of depression and severe mental illnesses. I was not able to find Aluminum Carbonate at Fisher or other chemical suppliers, so if it does exist at all, it is not commonly commercially available. Nimur 23:31, 9 July 2007 (UTC)

This is from the first search result on aluminum carbonate

Aluminum is a naturally occurring substance. Aluminum carbonate is the carbonate salt form of aluminum designed for oral ingestion. Aluminum carbonate is used to treat the symptoms of increased stomach acid in conditions such as heartburn, acid reflux, acid indigestion, sour stomach, and stomach ulcers. Aluminum carbonate is also used to treat, control, or manage high levels of phosphate in the body. Aluminum carbonate is also used with a low phosphate diet to prevent the formation of phosphate urinary stones.

I'm pretty sure that it's a different substance from Lithium Carbonate based on the pharmaceutical use. Incidentally, a google search on Al2(CO3)3 turns up a number of indications that this is, indeed. the correct formulation of Aluminum Carbonate. Donald Hosek 23:43, 9 July 2007 (UTC)

This site from a chemical supplier [8] gives C₂HO₆Al as the formula.

They're the only site that gives that formula (doing a google search on C2HO6Al). Trying permutations of H, Al and (CO₃)₂ doesn't appear to give anything more. Digging a bit deeper, although there does appear to be a salt which is as above, the medical aluminum carbonate is, in fact, an "aluminum hydroxide-carbonate complex" which is medical in its use according to New and Nonofficial Drugs, By Council on Drugs (American Medical Association) Published 1963 Lippincott Donald Hosek 01:11, 10 July 2007 (UTC)

Renewable energy capacity of the planet

Say we covered all areas of the planet that were sunny enough with solar power equipment, all areas that were windy enough with wind turbines, etc, for all the different renewable energy sources there are. Would the total amount of electricity generated be as much as is currently generated by all methods for the whole planet. ie with current technology is there enough renewable capacity to meet current demand for electricity? Willy turner 21:15, 9 July 2007 (UTC)

There is more than enough renewable energy on the Earth to supply all the world's energy needs, but you're talking about a huge investment. Think solar panel farms the size of Kansas. 151.152.101.44 22:13, 9 July 2007 (UTC)

Sunlight, collectively, contains about 10,000 times the energy that humans consume. The potentially capturable wind energy is about ~7 times what humans consume. It is physically achievable to power the world on renewables, but it would require a major economic, industrial and political effort to make it happen. Dragons flight 23:31, 9 July 2007 (UTC)

If you really want to collect energy, I suggest a Dyson sphere. -- JSBillings 19:07, 10 July 2007 (UTC)

Yep - there is more than enough energy coming from the sun to power all of our needs. The problem is mainly the cost of putting enough solar panels/windmills out there. It's just not a reasonable cost...unless of course you believe that we are killing our planet - then any cost is justifiable. However, even with "free" energy, if we trap more sunlight - turn it into electricity then turn the electricity into heat - then we're lowering the albedo of the planet - and that too may have consequences...especially if we have this big CO2 blanket preventing that heat from radiating out into space. Using windmills to extract energy from the wind cannot be without consequences to the weather. There is literally nothing we can do that'll have no effect whatever because extracting energy for our needs is driving the net entropy of the system...and that means more heat. Whether the effect we have is significant or not is the key question. What we really, truly need is to use less energy - and to do that to a sufficient degree probably means reducing our population drastically. SteveBaker 23:59, 10 July 2007 (UTC)

Speed and energy

I am having a somewhat thought experiment I don’t have any scientifically answer on.

If you are in motion, does tossing (or shooting) an object while you are in motion, cause the object to move faster than you, without any extra energy compared to tossing while not in motion.

It’s important to know that I do not think of a closed environment, like inside a bus or a spaceship that are in motion. It must be outside, like on the back of a pickup truck or something like that (this also includes with other matter and in a perfect vacuum). I am also wondering what will happen if I supposedly am travelling at the speed of light, and then shot a bullet. Will the bullet then go faster than speed of light?

--82.196.221.117 21:20, 9 July 2007 (UTC)

Question one is a bit vague. If you toss an object ahead of you (ignoring things like air resistance), then it will move faster than you in that direction, regardless of your speed. Further, the object moves at the same speed relative to you regardless of your speed relative to anything else. You can throw a ball at X speed standing still or at X+Y speed (relative to the ground) if you are moving at Y. This is the normal everyday ignore-relativity answer.

Question two gets into relativistic stuff. For one, you can't be traveling the speed of light. The question as stated is meaningless. But suppose you travel 5 mph below the speed of light, and can throw a ball 50 mph? What then? Yay, relativity! In your frame of reference, you might as well say that you are standing still and the world is moving around you. The ball appears to travel away at 50 mph in whatever direction you throw it. To an outside observer who sees you moving at almost-but-not-quite-the-speed-of-light, the ball travels ever-so-very-gradually-faster-or-slower than almost-but-not-quite-the-speed-of-light (depending on if you threw it ahead or behind) but in no frame of reference does anything exceed light speed. — Lomn 22:20, 9 July 2007 (UTC)

The only difference between being in a closed environment (like a schoolbus) and the back of a pickup truck is that in the latter case you have wind in your face. As far as special relativity is concerned, there is no difference. And how much energy it seems to take differs based on what reference frame you are observing from. As far as the thrower is concerned, it takes the same amount of energy no matter what inertial reference frame he is in, except for what resistance he will face from the wind. As for whether the ball can break the light barrier, no. You can't reach the speed of light to begin with, so at best you would speed up to 99.9999...(ending somewhere, not repeating forever) percent the speed of light and then throw it. Now again, from your perspective, this is the same a throwing a ball while "stationary" (stationary, velocity, it's all relative). From someone else's perspective, the ball is merely going very slightly faster, by the relativistic velocity addition formula. 151.152.101.44 22:25, 9 July 2007 (UTC)

To get into the first question a bit more - before you throw it, your rock or whatever is moving at the same speed as the rest of the truck (let us assume that your buddy is a cautious driver who maintains a constant non-relativistic speed and makes no turns). If you toss it straight up (impart a vertical momentum), its motion along the road is unaffected. Ignoring air resistance for the nonce, it looks to you like the rock goes straight up and falls. To the friendly roadside vegetable-monger, the rock traces a nice parabola with constant horizontal motion and constant vertical acceleration. At slow speeds this can be a fairly decent approximation, as demonstrated by my high school physics prof. using a small cart with a spring-loaded launch tube to toss and catch a ping pong ball while in motion. Turning air resistance back on, the rock is subject to a backwards force since the surrounding air will generally not be moving with the same velocity as your buddy's truck. Still, a gentle lob of a full can of beer out the window is, so I am reliably informed, quite sufficient to transform a common roadsign into a frothy dented mess. I am not clear on the energy part of your question, but kinetic energy explains the v² relation and might help. -Eldereft 08:03, 10 July 2007 (UTC)

Theoretically, Newton's first law says a body in motion tends to remain in motion. Your projectile is traveling at the same speed you are when you are moving. Any force you exert on the object will increase the speed of the object, affected slightly by air resistance .

What causes ice cubes to stick, like your tongue to a pole?

Exactly what force(s) cause partially melted ice cubes to stick to each other so quickly and so strongly, or your tongue to a metal pole in wintertime? (I'm assuming it is the same force(s).)

It's simply the freezing of water. If an object well below the freezing temp of water, like an ice cube or pole, comes into contact with liquid water, it causes that water to freeze to the object. Are you asking why water ice adheres to solid objects ? StuRat 01:37, 10 July 2007 (UTC)

Does Regelation play a part? -- JackofOz 01:44, 10 July 2007 (UTC)

Regelation may be the answer to ice cubes sticking together (but the article itself expresses some doubt, due to the enormous pressure required to melt the ice) but tongue sticking to a metal pole is for a different reason. It is just that the water content on your tongue gets frozen, binding the tongue and the pole. The same thing happens if you wet your finger and touch the pole. If the water film on your skin is thin enough (to freeze at the contact of the pole), then your finger will stick to the pole. -- WikiCheng | Talk 04:41, 10 July 2007 (UTC)

The surface of your tongue isn't smooth!

I think the reason that tongues are especially vulnerable is that they have a large surface area due to all of the little Papillae (taste buds) - so you aren't just talking about a smooth surface (like skin) that could just slip off of the ice - you're freezing all of those tiny bumps into the layer of ice - posing a significant mechanical problem. Also, for skin, the blood pumping through the finger (or whatever) will melt the ice that's in contact of the skin - making it relatively easy to come un-stuck. I don't think there is enough (or indeed any) blood flow through those buds to allow them to melt their own way out of the ice. SteveBaker 23:47, 10 July 2007 (UTC)