Science desk
< May 18	<< Apr \| May \| Jun >>	May 20 >

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.

May 19

Tree questions

Is tree really absorbed CO2 and release O2 in day time, and the contrary at night? Are all kind of trees have the same characteristic? And what species of trees produce the largest amount of O2? When we sleep in the forest at night, can we suffered from lack of oxygen? Thanks for the responds. roscoe_x (talk) 01:46, 19 May 2009 (UTC)[reply]

All plants perform cellular respiration, which consumes oxygen and releases CO2. However, this effect is completely overwhelmed by the action of photosynthesis, of which oxygen is something of a side-effect. Because plants manufacture their own oxygen, the "drain" on atmospheric oxygen is minimal. Go ahead and sleep outdoors; it'll do you good! Incidentally, there is an urban legend that you shouldn't bring flowers to people in hospitals because the plants supposedly suck the oxygen out of the room. Complete nonsense. Matt Deres (talk) 03:10, 19 May 2009 (UTC)[reply]

(EC) Matt, I'm no scientist, but I think there is something wrong with that last post. It implies that plants take in oxygen, then release CO2 (contrary to what I and the OP have been told in primary school) and yet still have enough oxygen to release that too, on account of photosynthesis. So, the idea of the Amazon rainforest getting depleted adding to the CO2 level(or at least not reducing it) and thus causing global warming is nonsense? Planting more trees would not help, because they suck oxygen from the atmosphere and not CO2? Are you sure about this? Question asked in all good faith - not sarcastically --KageTora - (영호 (影虎)) (talk) 03:22, 19 May 2009 (UTC)[reply]

Ha! Either I misread the answer or someone changed it while I was writing my query. Forget it. Been a long night.--KageTora - (영호 (影虎)) (talk) 03:25, 19 May 2009 (UTC)[reply]

Yeah - exactly - the amount of O2 they produce (and CO2 they absorb) during the day more than makes up for the small amount of O2 they consume and CO2 they produce at night. Also, it's not just trees - all green plants from the teeny-tiniest green algea to the giant redwoods do that. SteveBaker (talk) 03:17, 19 May 2009 (UTC)[reply]

This kind of question keeps coming up. The Plant article seems to be hopelessly lost in taxonomy and basic plant concepts like what parts do what and the question above get one on a wild goose chase through highly specialized articles. If one can find anything to begin with, that is. Thinking of the post about organizing information in a tree structure earlier this month maybe someone with enough knowledge could sort out an article for the non-specialists. I don't feel comfortable starting something, because my last biology lesson was a couple of decades ago and in my experience any article started without enough ooomph just gets deleted. 71.236.24.129 (talk) 06:53, 19 May 2009 (UTC)[reply]

I think your idea is good. I think Wikipedia should have a FAQ page on each of its article. roscoe_x (talk) 14:25, 19 May 2009 (UTC)[reply]

There is always the Simple English Wiki - although in this case, their plant article is probably waaay TOO simple. SteveBaker (talk) 02:53, 20 May 2009 (UTC)[reply]

Not all plants absorb CO₂ and release O₂ in day time and do the opposite at night. Keeping it simple, CAM Plants take in CO₂ during the night and convert it to oxygen during the day as a way to keep the plant from losing too much water. I'm not sure when most of the oxygen is released, but my hunch it happens mostly during daylight hours. As to what plant produces the greatest net O₂, I'm not sure, but it is likely not a species of tree. Someone answering a similar question stated that "the largest fraction of the planet's molecular oxygen is not produced by tree and other landbased plants but photosynthetic organisms in the world's oceans." I can't validate their answer, but I wouldn't be surprised if it was true. Sifaka ^talk 03:31, 20 May 2009 (UTC)[reply]

dimensional question

when a wave traverses a medium, the displacement (Y) of a particle located at x at time t is a*sin(bt- cx), where a, b and c are constants. what are the dimensions of b??

the dimension of Y is [L], and that of t is [T]. but should i write the dimensions of x as [L} or ... something else? 122.50.135.154 (talk) 05:44, 19 May 2009 (UTC)[reply]

Ya you're right. x is [L]. Which means c must be [L^-1], as you can't take the sine of anything except a number. Similarly, b is [T^-1], and the sine of anything is just a number, dimensionless. So a is [L].... There seem to be a lot of questions on dimensional analysis :-)..Rkr1991 (talk) 07:28, 19 May 2009 (UTC)[reply]

Almost right. "c" is actually radians/L, and b is radians/T, assuming your sine function is in radians, as it usual in mathematics. If your sine function is in degrees, replace "radians" with "degrees". The "a" is an amplitude, "b" is frequency, and "c" is phase shift.-Arch dude (talk) 20:31, 19 May 2009 (UTC)[reply]

Radians are generally considered to be dimensionless. They are the ratio of two lengths (a radius and an arc length). --Tango (talk) 20:38, 19 May 2009 (UTC)[reply]

explosive force calculation based on weight.mythbusters??

Hi

I am confused about something I saw on mythbusters the other day, they make a cannon that launches a 6 pound bowling ball 1500 feet. Yet the cannon itself barely moves backwards. shouldnt a force that can move 6 pounds 1500 feet move a cannon that weighs around 150 pounds about 50 feet? or does something else effect this ? I mean i would think that a force powerfull enough to push a 6 pound cannonball 1500 feet would have at least enough force in the other direction to move a 150 pound cannon about 20-30 feet, but the cannon just rolls back like a foot and falls over.

how does the calculation for the amount of pressure needed to move heavier and heavier objects work?

Thank you. —Preceding unsigned comment added by 79.68.210.245 (talk) 08:23, 19 May 2009 (UTC)[reply]

The canon would move a distance at a ratio inversely proportional to the ratio of masses, if there were no other forces acting (eg in space). But in this case, the frictional force between the canon and ground would presumably be much higher than that between the canon and ball, by design. So the reaction force is mostly balanced out by this frictional force, leading to little acceleration. Friction is dependant upon both mass and the friction coefficients of the materials used, hence heavier objects need more force to move on Earth than a simple momentum calculation would suggest. Recoil might have more info (it might have had a recoiling barrel on springs for example, so the momentum is aborbed by that and prevents large backwards movement).Yob Mod 09:22, 19 May 2009 (UTC)[reply]

AAAh thank you, your suggestion of friction, plus the recoil article helped. apparently some cannons and guns can be designed to have more chemical energy tranferred to the projectile than the gun. That would explain it. this is the quote "bullet fired from an M16 rifle has approximately 1300 foot-pounds of kinetic energy as it leaves the muzzle, but the recoil energy of the gun is less than 5 foot-pounds. The reason mechanical energy is not conserved is because much more of the chemical energy released during powder combustion is transferred to the bullet than is transferred to the gun."

How would they do that? —Preceding unsigned comment added by 79.68.210.245 (talk) 10:08, 19 May 2009 (UTC)[reply]

Actually, nearly any gun will do that by the simple laws of physics. Action=reaction applies to impulse - the gun and the projectile (plus the escaping gas, if we want to nitpick) have to have a total impulse that is zero - in other words, the impulse of projectile and the gun will have the same magnitude but opposite directions. Since impulse is mass times velocity, but the gun is a lot more massive, the projectile is much faster than the gun. Kinetic energy is mass times velocity squared, so that higher speed translates to a much higher kinetic energy. --Stephan Schulz (talk) 11:22, 19 May 2009 (UTC)[reply]

Working through the equations for parabolic motion and conservation of momentum, if the cannon were on frictionless wheels, it would move backward at somewhat less than 5 mi/hr after the shot. If it isn't on wheels, and considering that the shot is probably angled upward at about 45 degrees resulting in a strong downward push, friction would probably keep it from moving.

I am surprised that no one on refdesk spotted that, "The reason mechanical energy is not conserved is because much more of the chemical energy released during powder combustion is transferred to the bullet than is transferred to the gun." is a non sequitor that makes no sense.

"The reason mechanical energy is not conserved is because" there is no law of conservation of "mechanical energy". In any case, energy is not a vector quantity and the energy of the gun moving backward will not somehow cancel the kinetic energy of the bullet.
In a gun/cannon, chemical energy (from the explosive) is converted into mechanical energy (+ heat, sound etc), and total energy is of course conserved.
More importantly, for understanding recoil: Momentum is also conserved. The "positive" momentum (mass*velocity) of the bullet is matched by the "negative" momentum of the gun + shooter + earth + exhaust gases.

Can someone take a stab at rewriting the Recoil section ? Abecedare (talk) 16:27, 19 May 2009 (UTC)[reply]

What we're missing here is that the total momentum of the entire system is constant - that includes bullet, gun AND the gasses produced by the propellant. So in a "recoilless" gun (well, they have some recoil - but less), some of the propellant is sent sideways and backwards at very high speeds - and this removes some of the momentum from the recoil. But certainly the bullet's mass is much less than the gun - so the force acting on the gun is the same as the bullet - but the resulting acceleration is much lower. In the case of the Mythbusters' cannon - the friction with the ground is transferring some of that momentum to this big planet that has a REALLY big mass and consequently hardly accelerates at all. It's also common to have some kind of elasticity in the system (eg a padded shoulder stock) that spreads the recoil's energy out over a longer period of time - thereby reducing the instantaneous force to something much easier to handle. SteveBaker (talk) 19:52, 19 May 2009 (UTC)[reply]

Also, what everyone is forgetting is that the cannon is not fired straight parallel to the ground. If it were, it would likely roll backwards some distance. The cannon is usually fired at an upwards angle, which means much of the recoil force is directed into the ground. Much of the energy therefore goes into deforming the ground under the cannon rather than pushing the cannon backwards. --Jayron32.talk.contribs 00:56, 20 May 2009 (UTC)[reply]

cats landing on their feet

House cats always seem to land on their feet. Does this self righting reflex extend to other members of the cat family, such as jaguars, cougars, or tigers? 65.121.141.34 (talk) 14:09, 19 May 2009 (UTC)[reply]

Probably only if they are habitual tree climbers, like leopards and unlike lions. - GlowWorm. —Preceding unsigned comment added by 174.130.252.35 (talk) 14:15, 19 May 2009 (UTC)[reply]

As an interesting sidenote: Cats can only self right if the height from which they fall gives suffivient time to execute the reflex. Some studies (and i wish i still had that link!) showed that cats falling from either very low or high altitudes survived the fall more often then cats falling from heights in which they cannot execute the full reflex - The writers of course noted that there was a maximum height in which cats tended to survive more then cats falling from lower heights. Excirial^{(Contact me,Contribs)} 14:35, 19 May 2009 (UTC)[reply]

No, Wikipedia does not have one page for this...it has two!

The High-rise syndrome article has some good cites supporting the number-of-floors effect. Might want to copy them to the Cat righting reflex article, which presently only cites Straight Dope. DMacks (talk) 15:37, 19 May 2009 (UTC)[reply]

The question could be rephrased "Can big cats right reflexively, or is this just a 'little cat feat?'" See also Buttered cat paradox. Edison (talk) 16:44, 19 May 2009 (UTC)[reply]

Cats I have known could all right themselves when dropped from amazingly low heights, like 1 foot. Edison (talk) 18:36, 19 May 2009 (UTC)[reply]

The height from which cats suffer the highest fatality rate, ie. heights higher or lower than this are more likely to allow the cat to right itself properly and survive, is approximately seven storeys. This is because acceleration due to gravity causes the cat to become rigid, but once the terminal velocity is reached, the cat has an easier time trying to right itself. ~A H 1^(TCU) 01:59, 20 May 2009 (UTC)[reply]

So does this work with the big cats too? 65.121.141.34 (talk) 15:09, 20 May 2009 (UTC)[reply]

I suspect that some big cats have a righting reflex, but that it is less effective because big cats are more massive and so must absorb considerably greater force of impact for the same velocity. Small wildcats probably pull this off better. Dcoetzee 05:55, 21 May 2009 (UTC)[reply]

Which is worse, a drop-bear or a drop-tiger? DMacks (talk) 06:27, 21 May 2009 (UTC)[reply]

In reading through this, I checked out the Buttered Cat Paradox which led to the Irresistable Force Paradox. My question is about this latter. IF an irresistable force and an unmovable object did exixt and were to meet, wouldn't they simply cancel each other out (i.e. annihilate each other)? Why or why not (other than these forces/objects can't exist)? —Preceding unsigned comment added by 209.161.223.123 (talk) 03:42, 22 May 2009 (UTC)[reply]

mass increase or mass energy equivalence

which one did einstein formulate first? mass increase in relativity or mass energy equivalence? if he formulated mass energy equivalence first, can some one give the derivation first?--harish (talk) 14:59, 19 May 2009 (UTC)[reply]

Both came in 1905 papers, but the mass increase came first, in "On the Electrodynamics of Moving Bodies". Mass-energy equivalence was first directly presented, I believe, in the later 1905 paper "Does the Inertia of a Body Depend upon its Energy Content?". See special relativity and mass-energy equivalence for more information. Looie496 (talk) 15:31, 19 May 2009 (UTC)[reply]

Weren't the units of work or energy (such as the joule in the MKS system) given in kilogram meters² per second² before 1905? This meant that energy was already in units of mass times velocity squared. Was Einstein the first to notice this? Edison (talk) 17:06, 19 May 2009 (UTC)[reply]

KE={\frac {1}{2}}mv^{2}

was known long before Einstein, that gives you the units. --Tango (talk) 17:15, 19 May 2009 (UTC)[reply]

Right, but having the same units is not the same as being interchangeable. (Think about how much pathological physics would result...) Einstein not only noticed the units, but explained a correct equivalence relationship. Nimur (talk) 05:44, 20 May 2009 (UTC)[reply]

Of course, I was just pointing out that Einstein wasn't the first the notice the units, they were common knowledge long before he came along. --Tango (talk) 12:06, 20 May 2009 (UTC)[reply]

artifact hoaxes

Which scientific or historic artifact was accepted as genuine for the longest period of time before it was later discovered to be a hoax or forgery? 65.121.141.34 (talk) 15:08, 19 May 2009 (UTC)[reply]

This is totally unauthoritative, but:

I think it must be a religious artifact of some sort, like a church claiming it has part of the True Cross or some other relic — at this point these claims are probably being made in good faith but human nature suggests that most of them involve somebody lying at some point. Does this still comprise a hoax?
The Talpiot Tomb is around 2000 years old and was discovered in 1980; some claim that one inscription reads "Yeshua bar Yehosef", or "Jesus son of Joseph". Hoax? Concidence? Who knows.
More contemporaneously, the 1934 "Surgeon's Photo" of the Loch Ness Monster was revealed as a hoax in 1994. That's sort of an artifact.

The right answer may be some hoax that is as of yet undetected. Tempshill (talk) 15:39, 19 May 2009 (UTC)[reply]

Piltdown Man is one that creationists often point to that "discredits evolution". It was exposed as a hoax in 1953, but some scientists were skeptical from the start. Also, what about those inscribed balls found in South America? The name is eluding me... -- MacAddct1984 ^{(talk  contribs)} 16:02, 19 May 2009 (UTC)[reply]

The consequences of Piltdown Man went on long after the hoax was exposed. I wasn't born until 1955 - and I clearly recall being taught that Piltdown Man was 'the missing link' - and that must have been around 10 years later! It takes a long time for syllabuses and school books to get rewritten! If you ever get the chance to visit the little village of Piltdown - be sure to drop into their pub: "The Missing Link" - it serves some of the finest Real Ale I've had the pleasure of sampling. SteveBaker (talk) 04:07, 20 May 2009 (UTC)[reply]

I'm betting it's a book of some kind. As I recall, there are works that were attributed to writers like Aristotle for over two thousand years but eventually demonstrated by textual analysis to be forgeries. Unfortunately I have only the vaguest recollection of any of this, not enough to dig up sources. Looie496 (talk) 16:55, 19 May 2009 (UTC)[reply]

Klerksdorp Spheres? --Sean 17:39, 19 May 2009 (UTC)[reply]

Our literary forgeries article says One of the longest lasting literary forgeries is by Pseudo-Dionysius the Areopagite a 5-6th century Syrian mystical writer who claimed to be a disciple of Paul the Apostle. Five hundred years later Abelard expressed doubts about the authorship, but it was not until after the Renaissance that there was general agreement that the attribution of the work was false. In the intervening thousand years the writings had much theological influence. Looie496 (talk) 17:47, 19 May 2009 (UTC)[reply]

Turin shroud? The Bible? 89.242.109.25 (talk) 09:16, 20 May 2009 (UTC)[reply]

I have not seen anything proving that either of those are hoaxes or forgeries, though the church does not seem to allow much in the way of testing such relics as the shroud. 65.121.141.34 (talk) 15:07, 20 May 2009 (UTC)[reply]

See Radiocarbon 14 dating of the Shroud of Turin. 78.146.198.122 (talk) 20:50, 20 May 2009 (UTC)[reply]

Why would the Bible be a hoax? It's pretty well researched when it's specific books were written, and I've never heard of anyone claiming that it was written a lot later. --131.188.3.21 (talk) 20:51, 20 May 2009 (UTC)[reply]

momentum and relativity

take two coordinate systems K and K' . K' is moving with a velocity of v relative to K. An object is moving with a velocity of u relative to K'. will the observers in K and K' agree with the momentum and velocity of the object?--harish (talk) 16:11, 19 May 2009 (UTC)[reply]

Looks like a homework problem (which we don't do). Looie496 (talk) 16:57, 19 May 2009 (UTC)[reply]

It looks too general for a homework problem to me. --Tango (talk) 16:58, 19 May 2009 (UTC)[reply]

No. Velocity and momentum are always relative to a coordinate system, different systems will get different values for them. What velocity observers in K will measure depends on whether you are talking about simple Galilean relativity, in which case you can just add the velocities, or Special Relativity, in which you need the appropriate velocity addition formula. --Tango (talk) 16:58, 19 May 2009 (UTC)[reply]

biomedical projects?

i am applying for a scholarship for which i am supposed to do a BIOMEDICAL PROJECT.i need some information regarding this.what is a biomedical project?what am i supposed to do?is any paper work included?is it all about collection of some data or woking out something new? —Preceding unsigned comment added by 115.241.146.220 (talk) 17:25, 19 May 2009 (UTC)[reply]

:Pardon me for this observation, but if you don't know what a biomedical project is why are you wasting your time applying for the scholarship? --TammyMoet (talk) 19:01, 19 May 2009 (UTC)[reply]

BIO stands for Biological, while Medical stands for MEDICINE. In short, i assume that you will have to do some medicine related project. As for paperwork and working data out: How could we know? A project can be anything; it all depends on how you define the goals of the project. However i tend to agree with the user above me - If you don't even have a basic clue about the mere meaning of the word is it wise to apply for such a project? Most times at least some background knowledge is required to successfully complete a project Excirial^{(Contact me,Contribs)} 19:08, 19 May 2009 (UTC)[reply]

Most likely "doing a biomedical project" means finding a mentor who has a lab that does biomedical research, working out with the mentor a project that involves lab work, and then writing up the results. Beyond that, the details may vary. Looie496 (talk) 19:41, 19 May 2009 (UTC)[reply]

The best advice is to contact the people offering the scholarship directly. They aren't trying to mess with you; they will answer your questions directly. It's always best to contact the people directly involved rather than random strangerz on deh intrawebz. Those people will be able to answer your question directly. --Jayron32.talk.contribs 00:51, 20 May 2009 (UTC)[reply]

I've gotten a few scholarship before, which required having a project planned out. I basically just wrote to a (large) number of professors whose web-pages looked interesting, explaining the requirements for the scholarship. Most profs are very happy to help if you will be be bringing your own funding. However, i also had all the qualifications needed - for a biomed project scholarship, i would think the applicant should have experience in biology or medical research, at least at the undergraduate level.Yob Mod 09:49, 20 May 2009 (UTC)[reply]

Number of individual lifeforms on this planet?

Is there an estimate of the number of individual lifeforms on our planet? Meaning, all 6 billion humans, every individual insect, arachnid, invertebrate, blade of grass, etc. My second question is, are there more galaxies in the universe, than there are individual lifeforms on our planet? ScienceApe (talk) 17:58, 19 May 2009 (UTC)[reply]

If you're just counting lifeforms, virtually all of them are bacteria or archaea. They're hard to count, but one estimate is on the order of 5 x 10³⁰. Looie496 (talk) 18:19, 19 May 2009 (UTC)[reply]

As for the amount of galaxies: As estimate is that there are between 10 billion and 1 trillion stars, all which may or may not have planets orbiting them. If we were to count every metheorite, planet and star then the numbers would be drastically higher. Higher then the amount of lifeforms we have? Possibly - the galaxy is a massive place and our knowledge about it is still very localized. Excirial^{(Contact me,Contribs)} 19:01, 19 May 2009 (UTC)[reply]

Sorry, you didn't ask for the amount of stars, but for the amount of galaxies. If i remember well the last estimate i saw was between 60 and 110 billion galaxies. Far less then the amount of estimated lifeforms. Excirial^{(Contact me,Contribs)} 19:03, 19 May 2009 (UTC)[reply]

It is necessary to clarify the word "universe". The entire universe may well be infinite and, thus, contain infinitely many galaxies. The observable universe is finite and our article says it contains "more than 80 billion galaxies". --Tango (talk) 19:11, 19 May 2009 (UTC)[reply]

Excirial, I think your stars estimate is way off. Our galaxy itself contains 100 billion stars. It's a hundred thousand light years side to side. It bulges in the middle, 16 thousand light years thick; but out by us it's just 3 thousand light years wide. We're 30 thousand light years from Galactic Central Point; we go 'round every 200 million years; and our galaxy is only one of millions of billions in this amazing and expanding universe. Tempshill (talk) 00:02, 20 May 2009 (UTC)[reply]

Has life got you down, Mrs. Brown? --Jayron32.talk.contribs 00:49, 20 May 2009 (UTC)[reply]

100 billion is between 10 billion and 1 trillion. Excirial initially misunderstood the question and thought it was about the number of stars in our galaxy, rather than the number of galaxies. --Tango (talk) 00:31, 20 May 2009 (UTC)[reply]

Since regardless of how you do it there are millions of times more bacteria on Earth than stars in the entire universe, it's all sort of irrelevant. Looie496 (talk) 02:44, 20 May 2009 (UTC)[reply]

Observable universe. --Tango (talk) 12:07, 20 May 2009 (UTC)[reply]

Film speed vs. digital gain?

I understand that film speed and signal gain in photography are about the same thing: sensitivity to light, and work pretty much the same way. Greater sensitivity allows for shorter shutter speeds while still keeping the image lightness identical, but produces noisier and grainier images. My question is, because once the light gets through the shutter (how much and for how long the shutter is open is identical), what happens then is fundamentally different between film and digital photography. The sensitivity is labelled with the logarithmic ISO scale in both anyway, using the same numbers. How well do these correspond with each other? How is it determined which film speed corresponds to which signal gain? Are even the bases of the logarithms the same? JIP | Talk 19:34, 19 May 2009 (UTC)[reply]

Film speed answers your question. In short, yes they should correspond with each other. --antilived^{T | C | G} 05:06, 20 May 2009 (UTC)[reply]

Amount of vegetable fat in ml

I've been rather surprised to learn that recent medical advice is that consuming reasonable amounts of vegetable oil (but not hydrogenated or trans fats) is better for you than trying to avoid all fats. http://heartdisease.about.com/cs/cholesterol/a/raiseHDL_2.htm "The best advice regarding fat in the diet appears to be this: 1) reduce the fat intake to 30 - 35% of the total calories in the diet - but probably no lower than 25% of total calories". How much in ml of vegetable oil is 1% of total calories in one's diet going to be? 78.149.232.7 (talk) 23:44, 19 May 2009 (UTC)[reply]

According to this page, vegetable oils contain about 120 calories per tablespoon (15 mL). Caloric intake will vary from person to person, but USDA/FDA standards are based on a 2000-calorie daily diet. 1% of 2000 calories would be 20 calories, so 2.5 mL of vegetable oil would supply about 1% of a typical diet's caloric intake, assuming vegetable oil is mainly fat, which it is. 4.242.147.206 (talk) 00:36, 20 May 2009 (UTC)[reply]

As a side note, why did you think a completely fat free diet would be healthy? This reminds me of the overly-simplified definition of healthy food 'low as possible in fat, high as possible in fibre' which would make paper the healthiest food. 80.41.33.31 (talk) 07:37, 20 May 2009 (UTC)[reply]

Be sure to see Eating Too Little Fats further down on this page. Conventional nutritionists and professional organizations (e.g., the USDA, the American Heart Association, the Institutes of Medicine) say that it is dangerous to consume less than twenty of calories from fat. Consuming more than two-thirds of calories from carbohydrates can increase triglycerides and lower HDL cholesterol. These experts say that an intake of 20-35% of calories is healthful.75.89.27.94 (talk) 23:21, 24 May 2009 (UTC)[reply]

Involuntary digestive organs?

Is there a common English term for the part of the body where food goes after being swallowing and before being felt as a need to poo? If we had to use anatomical terminology, I guess that would be from the pharynx to the... wherever the threshold of feeling a need to poo is. I was thinking of calling it "involuntary digestive organs" or similar... basically including oesophagus, stomach and the guts. Or is there a better term or even a non-medical plain English term?--Sonjaaa (talk) 23:45, 19 May 2009 (UTC)[reply]

Gastrointestinal tract. Dauto (talk) 23:51, 19 May 2009 (UTC)[reply]

Teenagers in school would call it the digestive system in Biology lessons - the link shows it's the same thing, so take your pick. 90.193.232.41 (talk) 18:05, 20 May 2009 (UTC)[reply]

Not involuntary but autonomic.
Sleigh (talk) 15:17, 24 May 2009 (UTC)[reply]

Climate Variation

Is there any kind of technology on the internet that lets you take a climate chart of a particular location, provided by the site, and do a search to come up with all the climate charts around the world that correspond most closely with the initial chart? This climate chart would include average monthly highs and lows and average monthly precipitation. —Preceding unsigned comment added by 189.4.53.90 (talk) 23:52, 19 May 2009 (UTC)[reply]

You could start at the Weather Underground, http://www.wunderground.com/, which has all sorts of great climate and historical weather information from many many cities around the world. Oh, and dispite the name, they have nothing to do with these people. --Jayron32.talk.contribs 00:46, 20 May 2009 (UTC)[reply]