Science desk
< June 27	<< May \| June \| Jul >>	June 29 >

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.

June 28

Are all flamingos pink?

Are all flamingos pink? --HappyCamper 00:15, 28 June 2007 (UTC)[reply]

Apparently not - Flamingo#Colour DuncanHill 00:24, 28 June 2007 (UTC)[reply]

OK, maybe I don't know how to ask this. Is there such a thing as a yellow flamingo, or a blue flamingo? --HappyCamper 00:28, 28 June 2007 (UTC)[reply]

From the information I can find on the different species on Wikipedia - they are all pink (subject to diet and age), but the Andean Flamingo has yellow legs. DuncanHill 00:33, 28 June 2007 (UTC)[reply]

If the flamingo ate blue food, would it become blue? Nimur 01:03, 28 June 2007 (UTC)[reply]

The color comes from particular compounds in their food, carotene if I recall correctly. -- JSBillings 01:16, 28 June 2007 (UTC)[reply]

According to [1], blue algae contains carotene, and turns the flamingos pink anyway. Nimur 01:18, 28 June 2007 (UTC)[reply]

In zoos you'll often see whitish flamingos, since artificial dyes turning them pink are costly. Normally the dye is made from carrot oil and a substance derived from shrimp skins. bibliomaniac 15 ^{BUY NOW!} 02:45, 28 June 2007 (UTC)[reply]

OK, so the explanation for the color of flamingos has to do with their diet...I suppose, similar to why salmon are colored the way they are? --HappyCamper 04:48, 28 June 2007 (UTC)[reply]

Red canaries too.[2] --Kurt Shaped Box 08:24, 28 June 2007 (UTC)[reply]

According to the Salmon article, the red color in Salmon does come from carotenoids in shrimp and krill. -- JSBillings 14:21, 28 June 2007 (UTC)[reply]

Have you ever seen Pink Flamingos? If not, be warned - see Trivia, dot point 2. -- JackofOz 11:01, 28 June 2007 (UTC)[reply]

In a zoo in Hungary they feed the flamingos with paprika to keep them pink because they can't afford shrimp. They looked fairly white to me though. —Pengo 16:20, 28 June 2007 (UTC)[reply]

Bird first aid

I have a cat and occasionally need to rescue birds or mice that she has caught and brought into the apartment. I want to do something to help the injured ones before releasing them back outdoors, but at the same time, I don't really want to do more than the minimum. I have an injured bird in a cage (actually a hamster carrier) and intend to release it as soon as it seems able to fly. Any suggestions on simple (i.e. inexpensive) things that might help a convalescing bird? Peter Grey 05:01, 28 June 2007 (UTC)[reply]

There is some advice from the RSPB here, but its prospects of returning successfully to the wild are not good and if you can reduce or prevent injuries, for example by putting a bell on the cat, the birds will fare much better.--Shantavira|^{feed me} 08:07, 28 June 2007 (UTC)[reply]

A bell on the cat would be very cruel to the cat - just imagine how big and noisy it is if you scale it up to human size. 80.0.109.226 00:20, 30 June 2007 (UTC)[reply]

The Quebec Society for the Protection of Birds may be able to help, website here [3] DuncanHill 11:15, 28 June 2007 (UTC)[reply]

I mis-read your userpage, you are in Ontario. The Ontario Society for the Prevention of Cruelty to Animals has some factsheets, see Guidelines for helping wildlife

Is this game a pyramid scheme?

How closely does a game such as this one resemble a pyramid scheme or MLM, keeping in mind that:

Clicks on a link are AFAIK much less rivalrous than cash.
Even if and once nobody was going to click any more recruit links ever, the game could still be succeeded at by the newer players. Although the players who had gotten the clicks would have a substantial advantage, this is probably true in most MMOGs anyway for the established players versus the new ones.

Neon Merlin 06:47, 28 June 2007 (UTC)[reply]

Fibroblast growth factors (FGF)

Can anyone tell me when is the production of FGF in the body increase, ie other words, under what conditions? Also, where is FGF produced. Thanks for helping me out.

I believe the article on Fibroblast growth factor and the review article it refers to may satisfy your needs. Anything else? Lior 09:09, 28 June 2007 (UTC)[reply]

recovering from nail-biting

hi, For a long time I have bitten my finger nails excessively to the stage where now, the distance from my cuticles to the end of my nail doesnt reach the end of my finger, not even close. its pretty ugly. anyway, i'm trying to give up but have a niggling question. On perfect nails, the red bit (apologies for not knowing any medical terms) extends to the end of the finger and the "over hanging" nail is white. Now, on my nails when i allow the nail to grow it is also that white colour, but as my nails grow longer, will the red bit grow longer as well? or will i end up with ridiculous looking nails where the nail is normal length but half of it is white as opposed to just the end bit like most people. if this is the case, is there any, um, corrective surgery? basically, i want non-repulsive nails, how can i best acheive this. thanks! 130.88.243.227 14:29, 28 June 2007 (UTC)[reply]

The line between red and white on your nail is governed entirely by where your nail loses contact with the flesh below. For instance, after some injury that pulls the flesh and nail apart (thus turning red bit into white bit) the nail color will go back to normal not long after flesh and nail are back together. Even when an entire nail needs to be removed, it grows back normal. So I would expect your nails to eventually look perfectly normal once they grow back out. — Laura Scudder ☎ 21:35, 28 June 2007 (UTC)[reply]

I wouldn't be so sure, after years and years of nail biting, the bit that used to be red would now be completely healed over, your nails may not go back to normal, or it may take a long time before they do, at any rate, having a slightly longer white bit then other people doesn't make you a freak. if you've stopped biting your nails, then they will get better, if you keep biting your nails they can only get worse.Vespine 00:07, 29 June 2007 (UTC)[reply]

toxic/ heavy metals

I need the introduction of toxic/ heavy metals. Also i need the literature on method of separation toxic/ heavy metals by liquid membranes.

A lot of the 'toxic heavy metals' are found in computers, so here's a good place to start. Just click on each of the elements, see if they are heavy metals, and read about the ones that are. I was shocked to learn that about 90% of an old-style CRT monitor's weight is comprised of lead. Yuck!Vranak

The lead shielding was there to protect you from the radiation generated by the elecron gun/beam. So it's a good thing. Lead's also beneficial for optical quality--they use a small amount in eyeglasses.[4] — RJH (talk) 22:44, 28 June 2007 (UTC)[reply]

The good news is that the lead in a CRT is in the form of lead glass, and vitrification is a very effective way of isolating toxic metals. --Carnildo 21:10, 29 June 2007 (UTC)[reply]

Einstein's Concept of relativity....

Hai Master minds.... I have a doubt in Einstien's Concept of relativity.I find that in my textbook,Under the heading Non Inertial FramesI find the following wordings "A frame of reference is said to be a non inertial frame,when a body not acted upon by an external force,is accelerated". Is this correct,and how can a body be accelerated without an external force?

It means accelerated relative to the frame. So for example, in a car turning a corner, you feel pushed outwards. There is no force pushing you, but in the frame of the car you are being accelerated (i.e. if the car could see it would see you being accelerated and not know why.) Therefore a rotating frame (the turning car) is non-inertial. An accelerating frame (i.e. one not moving in a constant speed and direction) is non-inertial. This outwards 'force' you feel is called centrifugal force and is often said not to exist, or to be virtual, as it results not from a real force but from the movement of the car, and is only seen from the car's point of view. Hope that helps. Cyta 16:58, 28 June 2007 (UTC)[reply]

Yeah, like he/she said. You seem to have the correct instinct, i.e. that in a normal well-behaved frame of reference that can't happen; a non-inertial frame has to be funky is some way. Typically, it's because the frame of reference is being accelerated, like being rotated, or falling down a gravitational field. You can see how from the point of view of whoever is being accelerated, an object that is just sitting there looks like it's being accelerated the other direction. Gzuckier 17:47, 28 June 2007 (UTC)[reply]

Bohr Model

I'm wondering how the Bohr Model of the atom explains the reactivity of the alkali metals. I have already read the article on bohr model and alkali metals. Is it something to do with the electrons? Thanks 217.41.217.24 16:53, 28 June 2007 (UTC)[reply]

Yes chemistry is all to do with electrons! Basically atoms are stable with a full shell of electrons, the alkali metals need only lose one electron to get a full shell, so they are very reactive. There reactivity increases as you go down the group as the electron you lose is further from the positive nucleus attracting it, which is also shielded by the electrons in between. This makes it easier for the outer electron to be lost. That's obviously a very basic description, but it should explain the main features. The reactvity can be explained using this shell picture, but strictly speaking the Bohr model is a mathematical model referring to hydrogen. It is also requires a full quantum mechanical model to make any numerical predictions about reactivity (quantum chemistry might cover this.) Cyta 17:03, 28 June 2007 (UTC)[reply]

Our solar system.

Does our solar system have a name of its own, other than "our solar system"?

I've seen a lot of science fiction call it Sol, the IAU seems to refer to it at the Solar System -__ʇuǝɯɯoɔɐqǝɟ 17:43, 28 June 2007 (UTC)[reply]

Hmm. more to the point, if our sun is Sol, what do we call the solar systems of other stars? Gzuckier 17:48, 28 June 2007 (UTC)[reply]

We already call them "The XXX system" where 'XXX' is the name of the star. So, if we found planets orbiting Alpha Centauri, we'd talk about "The Alpha Centauri System". SteveBaker 21:04, 28 June 2007 (UTC)[reply]

I get the feeling we'll cross that bridge when we get to it --_ʇuǝɯɯoɔɐqǝɟ 17:53, 28 June 2007 (UTC)[reply]

Science fiction frequently uses Earth and Terra for our planet, and Sol for our sun; and hence "Solar" would probably refer to the system around Sol (presumably other star systems are not "solar systems" at all). However, since these are fictional works, there is significant room for artistic license. Nimur 18:07, 28 June 2007 (UTC)[reply]

I suspect the reason SciFi uses "Terra" is because the name of the people who live here can be "Terrans" - which is much nicer than "Earthlings" which somehow makes us sound small and weak (like "Ducklings" or something!). The word "Sol" is widely used outside of SciFi - go to NASA's Mars rover web site for example - they talk about "Sols" - meaning one solar day on Mars. To complete the set - we now often call our moon "Luna" to distinguish it from other moons. This is a good way to think about things because if we ever do end up living on a planet orbiting another star, we're going to want to talk about "Sunshine" and "Sunrise" and not have to get into messes like "AlphaCentaurishine" or "Starshine". I doubt that people living on mars will talk about burying things in "regolith" - they'll still say "earth" (lowercase) as a synonym for "soil". I suspect that wherever humans live we'll end up talking about "The Sun" and "The Moon" as being the ones in the sky of wherever we live. But it's hard to guess what might happen that far into the future. SteveBaker 21:04, 28 June 2007 (UTC)[reply]

Maybe in the centuries it will take to perfect interplanetary / interstellar spaceflight, we'll make progress towards a universal language that makes sense. I've been a little disappointed with the efforts so far. Nimur 05:23, 29 June 2007 (UTC)[reply]

(Please don't use the word far - some of us are still trying to supress the terrible memories of that particular linguistic effort!) But I wonder who it will be who'll undertake to translate 1.8 million Wikipedia articles into this future universal language? The arrival of the Internet has done a lot to cement English as the universal language - and projects like Wikipedia can only serve to accentuate that. Any new language has an even larger uphill struggle than before to gain ascendancy - it's hard to imagine how that can happen. SteveBaker 14:49, 29 June 2007 (UTC)[reply]

The our in our solar system is redundant. We call the nearest star as Sun (or Sol). Solar system refers to the planetary system around Sun. The planetary systems around other stars wouldn't be called solar systems. I agree with SteveBaker ("the XXX system") -- WikiCheng | Talk 05:10, 29 June 2007 (UTC)[reply]

It's all the fault of those stoopid aliens who insist on saying things like "We'll be back in three of your earth days"...<sigh>. SteveBaker 14:49, 29 June 2007 (UTC)[reply]

Doesn't the Astronomical Union have a standard for this? Retarius 03:14, 30 June 2007 (UTC)[reply]

Twin paradox

this is a spesific example of the twin paradox...

Specific example Consider a space ship travelling from Earth to the nearest star system: a distance d = 4.45 light years away, at a speed v = 0.866c (i.e., 86.6% of the speed of light). The round trip will take t = 2d / v = 10.28 years in Earth time (i.e. everybody on earth will be 10.28 years older when the ship returns). Those on Earth predict the aging of the travellers during their trip will be reduced by the factor \epsilon = \sqrt{1 - v^2/c^2}, the reciprocal of the Lorentz factor. In this case ε = 0.5 and they expect the travelers to be 0.5×10.28 = 5.14 years older when they return.
The ship's crew members also calculate how long the trip will take them. They know that the distant star system and the earth are moving relative to the ship at speed v during the trip, and in their rest frame the distance between the earth and the star system is εd = 0.5d = 2.23 light years ("length contraction"), for both the outward and return journeys. Each half of the journey takes 2.23 / v = 2.57 years, and the round trip takes 2×2.57 = 5.14 years. Their calculations show that they will arrive home having aged 5.14 years, in complete agreement with the calculations of those on Earth.
If a pair of twins were born on the day the ship left, and one went on the journey while the other stayed on earth, the twins will meet again when the traveller is 5.14 years old and the stay-at-home twin is 10.28 years old. This outcome is predicted by Einstein's special theory of relativity. It is a consequence of the experimentally verified phenomenon of time dilation, in which a moving clock is found to experience a reduced amount of proper time as determined by clocks synchronized with a stationary clock. Examples of the experimental evidence can be found at Experimental Confirmation of Time dilation.

My question is, wouldn't the people in the spaceship age twice as fast as the people on earth if one looked at the relative roles in reverse?(say that earth is moving at .866E and that the ship is stationary) Im just curious as to why this situation cannot have reversed motion/benchmarks like other ones can./ cant the same thing apply to the people on earth making them age 10 years and those on the spaceship 5?

It could be reversed if everyone was initially on the ship and then some hopped out and got on the Earth and then the Earth fired rocket blasters and accelerated off into space and returned 10 years later. The problem you are having is that you feel it is fine to jump from one point of reference to another. That makes it difficult. Instead, simply ask - which object has energy added to it? The ship is the one with the added energy for acceleration. The Earth stays the same. So, the ship is the one in which time slows down. -- Kainaw^(what?) 19:34, 28 June 2007 (UTC)[reply]

Special relativity talks about how the world behaves as seen from an inertial reference frame, i.e., one that doesn accelerate. We can do calculations with quantities (lengths and times) as measured from Earth since it is not accelerating (not very much at least). The spaceship, on the other hand, has to accelerate to get up to speed, turn around at the destination and slow down when it comes back. The formulas of special relativity can therefore not be expected to yield correct results, which is the reason we cannot simply swap the roles. —Bromskloss 19:41, 28 June 2007 (UTC)[reply]

Exactly. The difference between the two frames is all in the acceleration.Gzuckier 15:55, 2 July 2007 (UTC)[reply]

Atomic Radius and Melting Point

What is the relationship between atomic radius and melting point? Why is this? Thanks 217.41.217.24 20:45, 28 June 2007 (UTC)[reply]

Both are properties of chemical elements? Both are numbers? There are patterns to each, but no easy relationship or trend between these two properties. See our article about the Periodic table to learn about trends of various properties, and the atomic radius and List of elements by melting point for actual numbers to look for anything of interest. DMacks 22:43, 28 June 2007 (UTC)[reply]

But why for the alkali metals does the melting point decrease as the atomic radius increases?

I'm making a guess here and assuming someone credible has stated to you that there IS a relationship. With a large atomic radius, the electrons in the outermost shell are less strongly bound to the atom. This may mean covalent bonds between atoms are more easily broken up, lowering the melting point. But this is just a guess EverGreg 08:37, 29 June 2007 (UTC)[reply]

Yes, decreasing melting point seems counter-intuitive, especially when using Van der Waals forces to explain melting/boiling point. However, we can't forget that the alkali metals are metals, and their melting point depends on the degree of metallic bonding. Going down the group, atomic radius is increasing, and the shielding of the valence electron (very important in metallic bonding) is also increasing. Since these electrons (in the "sea of electrons") are farther away from the nuclei, they do not interact as much with the (positively charged) nuclei, constituting a weaker metallic bond, with a lower melting point. For other groups, I think it gets really complicated, with Van der Waal's forces, metallic bonding, and multiple valence electrons making everything foggy. Just looking at a table with melting points, there does not seem to be a true correlation for much other than groups 1 and 18 (with group 18 being explained by Van der Waals forces). --Bennybp 16:00, 1 July 2007 (UTC)[reply]

Audubon copyrights

Are images of Audobon birds and animals now in the public domain since they are so old? Or has the Audobon family kept up with the copyright and owns all the images? I want to use a few audobon images in my artwork, but want to make sure its legal. thanks for your help with this.

This is a legal question, which we're not supposed to answer. I will anyway; use this information at your own risk. John James Audubon died in 1851 and that means the copyright in the U.S. on any work he did in the U.S. has expired long ago. Other countries have their own rules but I haven't heard of any ordinary copyrights lasting that long.

By the way, please include a title so your questions are separated from the one before. I've added one for you. --Anonymous, June 29, 2007, 00:00 (UTC).

Copyright Term and the Public Domain in the United States. 152.16.59.190 06:30, 29 June 2007 (UTC)[reply]