Wikipedia:Reference desk/Archives/Science/2006 December 9

From Wikipedia, the free encyclopedia

Science desk
< December 8 << Nov | December | Jan >> December 10 >
Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is a transcluded archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.


Contents


[edit] December 9

[edit] Nose bleed

hay anyone got any good home remedies for a nose bleed? possibly induced by alcohol. Englishnerd (not logged on!)

It's quite amazing that alcohol both thins the blood and raises blood pressure. [1] Do the usual Nosebleed stuff. --Zeizmic 22:45, 8 December 2006 (UTC)
Is it not quite unhealthy to be drinking so much alcohol that you begin to bleed?? Never heard of alcohol induced haemorrhage before... --Username132 (talk) 23:47, 8 December 2006 (UTC)
Maybe the alcohol made him pick a fight, and it was actually the fist hitting his nose that was the proximate cause of the bleeding. --Trovatore 01:56, 9 December 2006 (UTC)


never mind, good old ice cleared it right up! Thanks for the advice though! Eŋlishnerd(Suggestion?|wanna chat?) 00:34, 9 December 2006 (UTC)
My suggestion is to dip a facial tissue in ice water and insert it in the nose. You get the cooling effect and it also washes away the blood residue, which reduces itching that may lead you to rub it and reopen the injury. If you live in a place where the ground is cold enough, cold water from the tap may be good enough. --Anonymous, December 9, 02:44 (UTC).

[edit] Electromagnetic Radiation Communication Devices

hello,

how does a radio send information (data packets in binary code) to another radio? for example in a wireless internet link, how are the 1's and 0's transmitted over waves? through cable they transfer as 1 = n volts and 0 = 0 volts. How does this happen over radio waves?

thank you - jose

Most commonly through modulation of a carrier wave. On top of that (or sometimes cleverly built into that) is an encoding scheme, like manchester code. Take a look at the articles linked from the carrier wave article, and at Category:Radio modulation modes. -- Finlay McWalter | Talk 23:42, 8 December 2006 (UTC)
See Quadrature amplitude modulation too as this is a very common scheme. --Tbeatty 04:51, 9 December 2006 (UTC)


[edit] discovery of rhinovirus

I've been through many sites and have yet to it upon the answer for the discoverer of the rhinovirus. Is there anyone out there who has a scientific backround and can help ? —The preceding unsigned comment was added by Williamblackman (talk • contribs) 00:05, 9 December 2006 (UTC).

If you can't find it on the internet, you might want to go to the last reference listed in the article, which appears to be the oldest, and use the reference list in the back of it. BenC7 02:08, 9 December 2006 (UTC)
According to Common cold#History, the rhinovirus was discovered in the Common Cold Unit in the 1940's–50's. –mysid☎ 08:27, 9 December 2006 (UTC)

[edit] Amount of indicated substance

Once you've found an indicator for a compound, how can you find out how much of that compound there is in the solution? Also while I'm at it, is the body (bone, organs, enzymes etc) made out of any inorganic compound? Thank you. Jack Daw 01:16, 9 December 2006 (UTC)

It will depend on what compound it is. Not sure about the other question; I thought enamel might be inorganic, but apparently it is 4% wt. organic. BenC7 02:02, 9 December 2006 (UTC)

[edit] Calories burned

Hi I am trying to calculate the number of calories I burn during weight lifting. If I can estimate the weight (in lbs) and the height (in ft) to get ftlbs, how would I convert this figure into nutritional calories? My guess would be:

Weight (lb) x Height (ft) x 1.355 J/ftlb x 1cal/4.184J x 1kcal/1000cal / 20% ([[2]])

Does this look reasonable? If so 60 reps of 50lb bicep curls through 3ft would burn 15 Calories, equivalent to about a teaspoon of sugar. Thanks! --71.212.160.45 03:39, 9 December 2006 (UTC)

I agree with the calculation. Some energy would also be expended in just holding the weights up; this goes directly into heat, so you can't calculate it the same way, but my guess is that it'll be much less than the energy spent in lifting. --Anonymous, December 9, 04:30 (UTC).
The calculation is correct, but not the assumptions behind it. When you do any kind of exercise, your heart beats faster, you breathe harder, and you produce more sweat, which evaporates and cools your body so it has to expend more energy to maintain its temperature. Of course, that doesn't have as much effect on weight lifting as it does on aerobic exercise, but I still think your estimate is low. —Keenan Pepper 04:47, 9 December 2006 (UTC)

[edit] Temperature of nuclear waste

What is the temperature of nuclear waste when it is stored? Adaptron 03:57, 9 December 2006 (UTC)

[3] indicates it is stored in an underground repository, presumably at near-ground temperatures. --71.212.160.45 04:06, 9 December 2006 (UTC)
You're ignoring the important fact that it generates its own heat by radioactive decay. The temperature depends on how fast it decays, how much energy each decay releases, and how fast the heat generated diffuses into the environment. —Keenan Pepper 04:34, 9 December 2006 (UTC)


As a rule, most materials (not in a vacuum) settle to equilibrium at the same temperature as their environment. So you would first need to find out the temperature of the environment it is stored in - deep underground, or in concrete containers, or whatever.
However there is an additional complexity in that nuclear waste (radioactive materials) also generate heat through radioactive decay, constantly, as they decompose to simpler (non radioactive) elements, and the time and energy they generate varies with their contents. In fact this is believed to be one of the reasons the earth has not yet cooled down all that much inside in its core. So you need to find the exact contents of the radioactive waste, and work out how much heat it gives off, which is hard to do and varies widely.
In fact, the temperature of the waste will not be the same as either its surrounding environment, nor the energy given off by the waste. The temperature of the waste will be fixed by how easily the heat generated by radioactive decay can pass into the environment. If heat can escape easily then the waste will adopt a temperature similar (or slightly higher) than the environment. If heat cannot escape easily then it will increase in temperature until heat loss through conduction convection and radiation equals heat generated by radioactive decay, in accordance with the laws of thermodynamics. For more on this see thermal equilibrium.
As one final twist, the waste may not all be at the same temperature. For the above reason it could be hotter at the center, if there is a lot of it. FT2 (Talk | email) 04:37, 9 December 2006 (UTC)
The temperature of stored waste is something that the repository designers choose; it's one of the engineering parameters they have to trade off when designing the repository. The mix of the waste, the size (and shape) of the waste containers, and the spacing between the containers are the primary factors that determine how hot the repository will be. Ventilation is too, if it's to be an open repository. Particularly for higher-level wastes, a (very) subcritical chain reaction condition can exist. which leads to more decay and thus more heat. For the repository designer this is both a blessing and a curse - the more radioactive a container is the more difficult it is to handle and the more dangerous (in the short term) it is, but the quicker it will decay. Designers of these kind of repositories (which are usually in tanks of water) can reduce the size of the containers, or adulterate the waste mix, to lower the activity. The designers of the Yucca mountain repository propose two operating modes, a high temperature mode and a low temperature mode (I don't think they've decided which they'll actually use). This DoE PDF says the high temperature mode will allow the material to get above the boiling point of water, and the low temperature mode won't. One of the hold ups on activating Yucca Mountain is the recent discovery that the rock from which it's made, tuff, may be more susceptible to heat-induced transformation (over the thousands of years of the repository's working life) that had been anticipated. This may mean that the designers will have to pick a yet-lower temperature mode. -- Finlay McWalter | Talk 12:00, 9 December 2006 (UTC)

One other note, radioactive materials with a shorter half-life will tend to be hotter, all things being equal, than those with a longer half-life. On the other hand, those with a short half-life will quickly decay to other elements, which may be stable, or radioactive with a short half-life, or radioactive with a long half-life. StuRat 12:07, 9 December 2006 (UTC)

I worked on this for a few years, with respect to a waste repository deep in rock, and the heat issue was problematic. It is controlled by the number of years you keep the waste in the 'swimming pools', or in above-ground concrete dry storage. --Zeizmic 14:05, 9 December 2006 (UTC)

[edit] Six pack

you know the six pack on your body shouldn't they be the same size at both the left and right of your body? and shouldn't they be at the opposite of each other. my right abs are bigger than my left. an i can only see two on my left and the top ab is lower than the ab on my right. what should i do? or ist supposed to be like that? —The preceding unsigned comment was added by 222.153.161.173 (talk) 07:09, 9 December 2006 (UTC).

This varies from person to person. It is pretty common for these muscles not to exactly align, and for the all 'six' not to be clearly visible (sometimes it may look like five, or even four). Go and have a good look at some bodybuilding magazines or pictures on the net, you'll see that this 'problem' is not that unusual. --jjron 14:30, 9 December 2006 (UTC)
Just check out the 'six pack' on the guy to the left: [4]
Okay... even the women have packages. That's just gross. --Russoc4 21:43, 9 December 2006 (UTC)

well is there anyway to fix it?

Yarrrrg. And that one dude even seems to have a tattoo on his tush. Ew. 192.168.1.1 4:40pm, 9 December 2006 (PST) —The preceding unsigned comment was added by 71.112.143.116 (talk) 00:35, 10 December 2006 (UTC).
There's three things that will make you attractive: a healthy head of hair, nice eyes, and a good six pack. The way to improve all three is by improving what you put inside of you: food and air. Be wary of all meats (and poultry), hydrogenated or partially-hydrogenated oils, any food additive that doesn't sound like it was around a hundred years ago, and of course house dust. There is nothing quite so insidious as house, car, and office dust. The outdoors are your friend! :) Mathiemood 00:36, 11 December 2006 (UTC)
Er, I think there are a few things more insidious than house dust. Meat is fine. As for the question, there is probably not anything that can be done, considering it is just one muscle, not a group of individual muscles. See rectus abdominis muscle. BenC7 03:04, 11 December 2006 (UTC)
Name one thing more insidious than house dust please!
Vis a vis meat; you are right, not everybody can live near the sea. Mathiemood 06:15, 11 December 2006 (UTC)
That and who is to say something that didn't exist a hundred years ago will deteriorate your physical fitness? Short of a new strain of disease like AIDS that leads to hospital stays and by extension not much of a chance to exercise, I can't think of anything that will impair your muscular growth, especially not in food. Or dust. --Wooty Woot? contribs 03:16, 11 December 2006 (UTC)
Well, if it wasn't around 100 years ago, it probably wasn't created in a laboratory by a bunch of pencil-dicked egg-heads looking to make a quick buck. Mathiemood 06:16, 11 December 2006 (UTC)

[edit] What you can learn about LASIK from commercials

There's a LASIK place near me that has been advertising a lot on the radio. One of their ads says that pregnant women cannot have LASIK. They don't go into the reasons on the commercial of course but it got me wondering. What does prenancy have to do with LASIK eye surgery? Is it the sedative used that may have adverse effects on the fetus? Dismas|(talk) 07:19, 9 December 2006 (UTC)

This document has the answer. –mysid☎ 08:23, 9 December 2006 (UTC)
Interesting. Thanks, Dismas|(talk) 08:47, 9 December 2006 (UTC)

[edit] Stains (biology)

what stains are best for seeing: 1) bacteria 2) human/animal tissues and fluids 3) plant life

this question is for personal use. ive asked my biology teacher and she responded that methyl (sp?) blue is perhaps best for animal tissues. —The preceding unsigned comment was added by PitchBlack (talk • contribs) 10:19, 9 December 2006 (UTC).

For bacteria the good old gram stain (crystal violet/fuchsine) is most likely what you're looking for. I agree with your biology teacher that methyl blue is most likely the best stain to use for animal cells. Plant cells though, I wouldn't really know what to use for that. Oh be careful with those stains some of them are very difficult to get out of your clothing. PvT 12:22, 9 December 2006 (UTC)
It really depends a lot on what you're hoping to see, and whether or not you have access to the tools of modern (er, at least mid-twentieth century) histology or not. Our article on biological stains may be starting point for your search.
The 'standard' (for historical reasons) for human tissues is the Haematoxylin and eosin stain (H&E), though there are a bunch of other choices of stains and counterstains if you're looking for specific features. H&E works well for animal tissues and in most plants, as well. (Once again, you may want to choose different stains based on the features you want to see.) As PvT said, Gram staining is a good choice for bacteria, if you're looking to identify basic shape and Gram positive/negative status.
If you're looking for carbohydrates (starch) then iodine works well. (It turns dark brown when it reacts with starch.) The Sudan stains are dandy for faits; Nile red is also excellent for demonstrating lipids in tissue.
Toluidine blue is a good stain for DNA. TenOfAllTrades(talk) 14:37, 9 December 2006 (UTC)
Oh and another word of advice. Always check the chemical properties of the dye you are working with. Some histological stains are suspected to be carcinogens (especially anything that binds to DNA) others are just simply toxic. If you are simply doing this for fun I'd avoid any of the more dangerous stains or ask a teacher to help you.PvT 15:22, 9 December 2006 (UTC)

[edit] Crossing satellites

Do we know of a celestial object that supports (natural) satellites that travel on orbits at an angle with each other but have the same diametre so that they effectively cross each other's path? Could such a system be stable? Keria 19:07, 9 December 2006 (UTC)

I can't say if such a system is known, however since the system you describe would seem to have at least three objects, proving it is indefinitely stable is probably not yet mathematically possible (see three body problem). One thing to consider, the two orbiting objects will have different trajectories due to the influence of the other, as well as responses to the more massive central body, which moves in response to both objects. If the orbits cross at one point, they may not necessarily cross indefinitely. --TeaDrinker 19:21, 9 December 2006 (UTC)
I don't think that this system is necessarily a three body problem. Even natural satellites can have a very large mass disparity (solar system, moons of Jupiter, etc.). Also, assuming two circular orbits have the same semimajor axis, they must necessarily intersect at two points (unless they are co-orbital), correct? -anonymous6494 21:05, 9 December 2006 (UTC)
What I was thinking of was the Restricted three-body problem, which is solvable analytically and numerically. -anonymous6494 21:14, 9 December 2006 (UTC)
Only in two dimensions. In the real three-dimensional world, the paths of objects very rarely cross at all. Pluto and Neptune are a pretty well-known example; their orbits are often said to "cross" but really they come nowhere near (and I'm not talking about resonance, just geometry). Melchoir 00:36, 10 December 2006 (UTC)
I stipulated that both orbits must be circular, and have identical semi-major axes. Neptune and Pluto satisfy neither of these conditions. Any two circles with the same radius and same center (i.e. two circular orbits) must intersect at exactly two (or infinity) points. -anonymous6494 03:47, 12 December 2006 (UTC)
See Epimetheus for a close approximation of what you describe. Additionally, two asteroids with identical semi-major axes would fit. "Stability" is relative. If the two satellites were not exactly 180° apart, the gravitational interaction between them would eventually shift their orbits so that the objects would some day both be approaching the same crossing node simultaneously. However, if the satellites were of sufficiently low mass, and the distance between them sufficiently large, their gravitational interaction wouldn't be of any importance as a practical matter. B00P 23:15, 10 December 2006 (UTC)

[edit] Embryology

What, if any, is the difference between the extraembryonic mesoderma and the exocoelomic mesoderm? Thanks Omalé 19:54, 9 December 2006 (UTC)

As I understand it, the exocoelomic cavity appears inside the extraembryonic mesoderm, there is no (separate) "exocoelomic mesoderm". See this reference. --Seejyb 21:52, 9 December 2006 (UTC)

[edit] Black holes of different sizes?

Black holes can have different sizes, from the supermassive black hole at the center of the galaxy, to miniature ones created in particle colliders. After reading the explanation above, the singularity at the center isn't a "thing" that can be measured, nor does it have a size, right? But it has measurable mass, doesn't it? Is that just the way it is, because the laws of space-time do not apply? Also, what determines the size of the event horizon (it has a diameter, doesn't it?). Massive black hole= large event horizon, tiny black hole= small event horizon? 192.168.1.1 1:15pm, 9 December 2006 (PST) —The preceding unsigned comment was added by 71.112.143.116 (talk) 21:11, 9 December 2006 (UTC).

The size of the event horizon is the Schwarzschild radius, at least for non-rotating, non-charged black holes. For this case, the only difference is mass, as you've indicated. -anonymous6494 21:23, 9 December 2006 (UTC)

Pretty much everything you said is correct. StuRat 22:13, 9 December 2006 (UTC)

Cool, thanks. So the schwarzchild radius is a quality of a black hole, but it is not tangible; like the earth's equator, yes? What's in the space between the schwarzchild radius and the singularity? Just vacuum and whatever matter is being sucked into the black hole, right? 192.168.1.1 4:35pm, 9 December 2006 (PST) —The preceding unsigned comment was added by 71.112.143.116 (talk) 00:31, 10 December 2006 (UTC).
In the theory of general relativity, the interior of the event horizon isn't qualitatively any different from the exterior. So, yes, you could identify that as being vacuum plus whatever's being sucked in. In reality, I don't think we know what lies behind the event horizon. Didn't someone seriously propose that black holes were fuzzballs of cosmic strings on the inside...? Melchoir 00:42, 10 December 2006 (UTC)
If we knew exactly what lies behind the event horizon, it would not be called an event horizon. --V. Szabolcs 13:52, 10 December 2006 (UTC)
But we could hope for a complete theory of gravity that accounts for all observed properties of event horizons and makes a reasonable, meaningful prediction about what lies behind them. Sure, we couldn't test such a prediction, but we should still be able to make one. Currently that theory is missing, and we are more ignorant than we absolutely need to be. Melchoir 17:46, 10 December 2006 (UTC)

A funny question: in the article I see "beyond which events cannot affect the observer" and "an outside observer cannot be affected by anything inside the black hole". Than how can gravity affect us? It certainly comes from the inside of the Schwarzschild radius. --V. Szabolcs 13:56, 10 December 2006 (UTC)

That's a very good question. If you can answer that one, you can be sure of getting a Nobel prize any time soon. David Da Vit 15:38, 10 December 2006 (UTC)
Just a guess, but visualize space as a flat sheet. As mass starts accumulating, it creates a depression. (This, I believe, is how Einstein's Theory of General Relativity interprets gravity.) Just before the black hole forms, you have a really deep depression. When the black hole is born, the depression is infinitely deep. But just because nothing can escape now doesn't mean the depression suddenly disappears. Voila! The gravitation resulting from the distortion remains. (P.S. When can I expect a call from Stockholm?) Clarityfiend 00:59, 11 December 2006 (UTC)
This does have similarities with my assumptions (that the spacetime is somehow different in the neighborhood). But if the singularity, after created, is not influenced by the black hole itself, what happens when the black hole will no longer be there? (it evaporates, or just moves away, orbiting a galaxy core or something like that) I have searched a lot to find out more about gravitational waves, but no one has ever explained how gravity waves could exit the Schwarzschild radius to affect surrounding space if they cannot go faster than light. Are they themselves immune to gravity? :) It is known that light is not. This brings me an idea. Did some scientists do some experiments to see if gravity waves could be bent around large masses just like light could be? --V. Szabolcs 16:05, 11 December 2006 (UTC)
How can a black hole no longer be there? In a sense, the black hole is the distortion in space-time. The matter that originally formed it has exited the universe, so it's not going to move around where we can see it.
Are gravitational waves affected by mass? What I read of the article doesn't seem to say. Clarityfiend 20:38, 11 December 2006 (UTC)
www2.yukawa.kyoto-u.ac.jp/~jgrg14/Proc/POS-23.pdf, along with other Google hits, seems to say that gravitational waves can be affected by large masses/gravitational lenses. Sounds a little weird to me - kind of like saying one water wave affects another, but what do I know? Clarityfiend 06:52, 12 December 2006 (UTC)
Are there any black holes so massive that even the black can't get out? - blank holes ...?
Black isn't really a color, it's the absence of color. So black holes are always blank. Clarityfiend 06:52, 12 December 2006 (UTC)
I know that movement is relative, but what about a star orbiting the galaxy core, or having some kind of movement and/or acceleration relative to other stars. What will happen with it's momentum when it eventually becomes a black hole? --V. Szabolcs 01:14, 12 December 2006 (UTC)

[edit] Old images of eyes

Why is it that in old (19th century) images such a plates or daguerrotypes, the eyes of people so often appear such a strange almost translucent shade? [5] [6] [7] I have not seen the effect in any modern 20th century black and white images. Is it a result of perhaps a wider spectral sensitivity (into the IR?[8]) of the older methods?--Deglr6328 21:33, 9 December 2006 (UTC)

Strange is subjective. Never the less, it could be just because the technology is different. Watch an older film that is natively black and white and compare it to a modern film that has its color removed. The quality is very different. --Russoc4 21:40, 9 December 2006 (UTC)
In early photography, the exposure might take 10 or 30 seconds. Metal headrests were used to keep the subject's head from moving, but the eyes were likely to blink and look around, leaving them looking blurred. Photos were also taken of dead people, posed to look alive, and there were sometimes post-mortem changes in the appearance of the eyes. Edison 00:29, 10 December 2006 (UTC)
It's also possible that they looked away briefly, if (as the article seems to say) daguerrotypes required a long exposure. I've taken long exposures of myself with black-and-white film where I didn't move my head, but looked away for a moment during the exposure. The eyes looked curiously washed-out; if this doesn't appear in all daguerrotypes, that might be the source. grendel|khan 00:39, 10 December 2006 (UTC)
Your eyes move even if you don't move them consciously: see Saccade. —Keenan Pepper 03:16, 10 December 2006 (UTC)

Until later in the 19th century Daguerreotypes were orthochromatic , being sensitive to blue-green and UV. Therefore the eyes "like limpid blue pools" (but in b/w). Adding polychromatic dyes came somewhere in the 1880s, I think. --Seejyb

Theeeere's the answer I was looking for! Very interesting. Thank you. Totally makes sense too since not all people's eyes have the weird color, only those that appear light to begin with. --Deglr6328 10:02, 10 December 2006 (UTC)
After playing around in photoshop with images of blue eyed people it is obvious this is the correct answer. If you remove the red component of an image before converting it to greyscale it makes the eyes look EXACTLY like the ones in the old daguerrotypes. Thank you again.--Deglr6328 11:24, 10 December 2006 (UTC)

[edit] Tryptophan hydroxylase reactivation/reformation

Case in point: the older generation MAOIs, which irreversibly inactivated monooxidases, only for new ones to reform within about two weeks. MDMA is said to (permanently) damage Tryptophan hydroxylase in serotonergic neurons, critical to the control of 5-HTP synthesis, a precursor of serotonin. Do these enzymes newly reappear after some time, or in some way can be reactivated (if so, howabouts?). Thanks. --Curious 22:05, 9 December 2006 (UTC)

Most cells that are capable of synthesizing an enzyme once can do it again. This applies to neurons and presumably to tryptophan hydoxylase. Theoretcally, however, even temporary interference with enzyme activity in neurons can have effects on both short-term and long-term neuron function because of the continuously ongoing strengthening and weakening of synaptic activities, and because of the activation of various compensatory events that occur when a cellular process is disrupted. alteripse 15:07, 10 December 2006 (UTC)

[edit] Paper Parachute

I'm trying to build a parachute out of only cheap white paper and tape. I can use up to 5 pieces of paper, but the parachute should be small when not in use (when sitting.) How should I go about this? I was thinking it through with one piece of paper. I folded a piece of paper in half lengthwise and then widthwise, and then folded the corners in towards the center. I then attached my heavy object to the center of the parachute and taped the corners and the midpoints of the edges down to the bottom of my heavy object so that if the wind hit the parachute, it would be rigid enough to hold, rather than give way to, air. This significantly reduced the parachute in size by folding it a fair amount inward. Regardless of the limit in size imposed for this project (20cmx20x30), is that a good idea? i dont want the wind to be able to simply push the parachute wings up. What about a rotating parachute? Good idea? How would one make it? I get the feeling it would be too technically difficult. Any suggestions you could give would be quite helpful, because the parachute part of this assignment is quite daunting. Thanks. Sashafklein 22:16, 9 December 2006 (UTC)

How about if you start by taping 5 pieces of paper together to make a cube with one side missing ? Then, use long strands of tape to connect to the object, going all the way from one piece of paper, down, past the object, up to the other piece of paper, like this:
         +------------+ Gap
         |            |
         |            |
         |            | Paper
         |            |
         |            |
         +            +
          \          /  
           \        /
            \ Obj. / Tape 
             \ ** /
              \**/
               --
Try to leave some gaps in the corners where the pieces of paper come together at the top of the cube. You need to allow a certain amount of air to escape at the top of the parachute or it will exhibit an undesirable behavior known as "squidding". You will likely need to test and make mods several times to perfect it. StuRat 01:02, 10 December 2006 (UTC)

That looks like it'd work quite well. Thanks a lot.Sashafklein 04:07, 10 December 2006 (UTC)

You're quite welcome, let us know how it works out. StuRat 14:49, 10 December 2006 (UTC)

I made that parachute and it worked until it flipped over near the end. That's ok, cause it was a practice run. I think I'm changing the parachute design, however, to fit into a smaller space. In order for the parachute to be really effective, it had to be large, and the way my teacher's scoring the project is that not only must the egg inside the contraption survive, (the whole point of this is to sucessfully drop an egg in a ten-straw 5-piece-or-paper lots-of-tape contraption so it doesn't break after a 16 meter fall) but the whole thing, when at rest, must also fit within certain small dimensions. The smaller the contraption, the higher my grade. I originally gave up on size and built your parachute, but since it squidded at the end anyway (my construction mistake - It was probably too well sealed), I figured I'd try something smaller if I had to re-do it anyway.

If you're interested: I took my five pieces of paper and cut large circles out of them. I then crumpled up all the paper again and again until it was soft and would bend easily in the wind, made a slit to the center, and then layed one side of the slit an inch or two over the other to form a slightly steep cone and taped it in that shape. I then stacked all five and attached them with room for expansion, so that when they drop, they'll all seperate upwards and catch air. It works pretty well, but the real test is on Tuesday. Thanks for your help at any rate. I now know how to avoid squidding (and have cut holes in the top of each cone to avoid it), so your advice has been quite helpful in the end. Thanks a lot. Sashafklein 01:41, 11 December 2006 (UTC)

You're welcome, good luck ! StuRat 05:32, 14 December 2006 (UTC)

[edit] engine

What does non turbo targa mean? There was iinfo about a car and it said non turbo targa. —The preceding unsigned comment was added by 70.115.14.36 (talk) 22:25, 9 December 2006 (UTC).

See targa top--Russoc4 00:41, 10 December 2006 (UTC)

And for the other part, a "non-turbo" is a normally aspirated engine, that is, one which lacks either a supercharger or a turbocharger. That means it will have less horsepower than a turbocharged engine of the same size. StuRat 00:46, 10 December 2006 (UTC)
Retrieved from "http://en.wikipedia.org../../../r/e/f/Wikipedia%7EReference_desk_Archives_Science_2006_December_9_9ab8.html"