Science desk | ||
---|---|---|
< May 28 | << Apr | May | Jun >> | May 30 > |
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. |
To start off, I am a 17 year old high school student that has just completed his first year of high school-level physics. I'm pretty smart (at least I like to think so), but if this question can't be answered with vocabulary and ideas that someone of my edjucation level will be able to understand, that's ok. The answer to this question is probably in Wikipedia somewhere, but in my reading I've only seen equations and explanations that I don't think I'll ever understand until sometime through college.
Question: If there is no such thing as perpetual motion, how can electrons keep moving around the nucleus of an atom? My guess is that at the level we're talking about, there's not really anything like friction in the common sense, so there's nothing to act against the electrons after they are moving, but then where does the energy come from to move them in the first place? Hypershadow647 ( talk) 00:03, 29 May 2008 (UTC)
It may be helpful to the OP that a "perpetual motion machine" is essentially something that can perform work indefinitely without an external source of power. Electrons moving around a nucleus, or moons orbiting a planet orbiting a sun, are perpetually in motion, although there is no energy expenditure to maintain that motion. ~ Amatulić ( talk) 18:34, 30 May 2008 (UTC)
what combinations work and do they¿ i know you cant give medical advice, but what does science say so far about the effectivity of them¨¿thnx guys —Preceding unsigned comment added by 75.69.26.8 ( talk) 03:20, 29 May 2008 (UTC)
What jobs and career options are there in relation with animation? —Preceding unsigned comment added by 117.194.225.94 ( talk) 03:55, 29 May 2008 (UTC)
Hi. I saw a '3rd Rock From the Sun' episode where mary albright puts this chemical on dick solomon's desk, because earlier they had been playing impractical jokes on one another. Dick comes in and sits at his desk. as soon as he puts his hands on the desk, they are instantly stuck. Then he uses too much force to get his hands off and he accidently puts his head on the desk and then is stuck to this position. My question is: Can this chemical really do that sort of thing, paste objects together that quickly? Jwking ( talk) 05:32, 29 May 2008 (UTC)
What part of the brain becomes more active during sexual arousal? Or at least, what part controls that. -- 68.90.143.120 ( talk) 06:30, 29 May 2008 (UTC)
I'm curious why the sky is orange during nighttime. First of all it was 10 pm so I discount the sun. It is relatively cloudy and rainy during the night and the clouds are actually the ones that is a dull orange. I live in Manila so the air pollution is strong but I can't account fo r the orange hue as we use fluorescent lamps here rather than oil or fires.-- Lenticel ( talk) 06:58, 29 May 2008 (UTC)
I was wondering how efficient generators are at converting mechanical energy from the rotating magnet to electrical energy? 61.69.132.119 ( talk) 07:32, 29 May 2008 (UTC)
Does anyone know where I could find mortality rates calculated as hazard rates? I'm trying to answer questions like, if a Canadian man makes it to the age of 93, what are his odds of surviving to 94? If an American baby reaches the age of 6 months, what are the odds of her surviving the remainder of her childhood? Thanks. moink ( talk) 12:36, 29 May 2008 (UTC)
I bought some plimsolls online from River Island, but they stink of plastic like they're from some crappy discount shoe warehouse.. I've put them outside to air but they still smell awful. I thought I'd ask you clever lot for some advice. Whack on the Febreze? Air tight container with some Bicarbonate of soda? Thanks in advance! 79.78.46.84 ( talk) 12:57, 29 May 2008 (UTC)
How does one cite matter from a chapter in a book that has contributors that are different from the editors mentioned on the cover and elsewhere? Which all authors are to be included in the citation?
Kindly help me with this doubt.
Thanks in advance.
Regards.
PS: Have posted the same query on the talk page of citations, but am not expecting a quick reply. Thanks.
—KetanPanchal
taLK 13:30, 29 May 2008 (UTC)
Heller, Steven, ed. The Education of an E-Designer. Heller, Steven and Karen Pomeroy. Design Literacy: Understanding Graphic Design.
I've read somewhere that if you're not having a full night's sleep, or if you're just taking a nap, certain sleep durations are better than others because you'll not be waking up during the "wrong" part of the sleep cycle. I think two recommended durations were given in the article I read, one for short naps and the other for longer sleep.
I can't find the article and don't remember what the recommended durations are. Can someone point me to some good articles/resources on the subject? —Preceding unsigned comment added by 71.162.242.15 ( talk) 16:53, 29 May 2008 (UTC)
When measuring earthquakes there are different sclaes, like Mercalli intensity scale and Richter magnitude scale. Why did the Japanese invent their own scale "shindo" ( Japan Meteorological Agency seismic intensity scale) (In Japanese called 震度)? Moberg ( talk) 16:57, 29 May 2008 (UTC)
Under the Nebular Hypothesis, the rotation of the solar system is caused by the contraction of the original cloud and, as it condensed, the rotation went from perhaps once every million years to that which it is today. The principle of the conservation of angular momentum is applied. The question is, however, what caused the original rotation? Any generally accepted reasons for the cause under this hypothesis, or are we still guessing? Boblaw1 ( talk) 17:52, 29 May 2008 (UTC)
What distinguishes the following technologies?
-- 141.161.98.180 ( talk) 18:12, 29 May 2008 (UTC)
what exactly will happen when we short two terminals of a common type of diode ,does there be any charge movement and a resulting effect on depletion region 202.125.143.75 ( talk) 19:25, 29 May 2008 (UTC)
Well I would like to build a switch which is switched on and off by clapping your hands twice. What do I need, and how do I do it? Bastard Soap ( talk) 20:29, 29 May 2008 (UTC)
In the event of a hypothetical doomsday scenario how long would a modern nuclear power plant be able to supply electricity before it shuts down? I know an that nuclear power plant's have some kind of dead man's handle mechanism as a failsafe but let's assume that it was turned off. How long could a modern nuclear power plant work on it's own? For hours, days, weeks or years? Mieciu K ( talk) 21:57, 29 May 2008 (UTC)
We have a page which lists lots of trigonmetric equations. Is there a similar page for physics equations. In particular "v = u + at", "s = ut + 0.5at^2", "F = ma", etc. Maybe also for electrical equations "V = IR" "Q = VC" etc. If it does exist you can't find it by searching for "v=u+at". -- SGBailey ( talk) 22:24, 29 May 2008 (UTC)
I was mulling over how to make demonstration logic gates using many different technologies. Obviously a mechanical AND gate can be made with two input levers which can be up or down pushing on opposite ends of a floating pivoted beam where the central pivot holds a flagpole. If both are down, the pole is down, if only one is up the the beam pivots and the pole is down, if both are up then the beam itself is raised and hence the pole is up. What other technologies are there and how might they be demonstrated? Hydraulic (liquid pressure?); Pneumatic (flow (or not)); electromechanical (relays); electronic (transistors and voltages); Pure optical (no idea how); Magnetic (how?), etc etc. Suggestions and advice on a postcard please... -- SGBailey ( talk) 22:35, 29 May 2008 (UTC)
| | | | | | | | -+----+- -+----+- | | | | | |_________| | \ * * / \ * * / \ * * / \ * * / \ * * / \* */ | | | |
Wiklearn ( talk) 23:42, 29 May 2008 (UTC)How is wind speed related to the height of ocean waves? At what wind speed would white caps appear? Wiklearn ( talk) 23:42, 29 May 2008 (UTC)
Trompes are simple devices that use the power of falling water to compress air. Trompes were used widely in the 19th century. They were used to provide the air for mines, blast furnaces pneumatic tools for alpine tunnel making, etc. The town of Cobalt in Ontario, Canada claims to have the only hydraulic air compressor (Trompe) left in the world http://www.cobalt.ca/ragged_chutes.htm Researchers in England have tried to use low pressure trompes (attached to an enclosed wind turbine and electric generator) to extract energy from the water running over weirs in a cost effective way. (Pdf is available if required). I believe that a dedfinition of trompe would help show people in poor countrys that energy is available from low grade (low head) hydro sources without the huge investment in machinery that is currently a barrier to using these (often high volume) sources of energy. —Preceding unsigned comment added by Gaiatechnician ( talk • contribs) 23:46, 29 May 2008 (UTC) Gaiatechnician ( talk) 23:47, 29 May 2008 (UTC)
Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed". I actually wrote it and my poor effort has been sitting there with that proviso (and doubt) over it for a long time. Just hoping to get it fixed. My sources are long ago photocopys from engineering manuals. I have made some so I know they exist. Gaiatechnician ( talk) 15:04, 30 May 2008 (UTC)
Such devices have existed. Within the last year there was an article in New Scientist showing methods of using low-head flow to compress air. The water flowed in the shape of a U taking air bubbles down to the submerged air reservoir in the middle. The water leaves at a lower level. Polypipe Wrangler ( talk) 10:23, 30 May 2008 (UTC)
Science desk | ||
---|---|---|
< May 28 | << Apr | May | Jun >> | May 30 > |
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. |
To start off, I am a 17 year old high school student that has just completed his first year of high school-level physics. I'm pretty smart (at least I like to think so), but if this question can't be answered with vocabulary and ideas that someone of my edjucation level will be able to understand, that's ok. The answer to this question is probably in Wikipedia somewhere, but in my reading I've only seen equations and explanations that I don't think I'll ever understand until sometime through college.
Question: If there is no such thing as perpetual motion, how can electrons keep moving around the nucleus of an atom? My guess is that at the level we're talking about, there's not really anything like friction in the common sense, so there's nothing to act against the electrons after they are moving, but then where does the energy come from to move them in the first place? Hypershadow647 ( talk) 00:03, 29 May 2008 (UTC)
It may be helpful to the OP that a "perpetual motion machine" is essentially something that can perform work indefinitely without an external source of power. Electrons moving around a nucleus, or moons orbiting a planet orbiting a sun, are perpetually in motion, although there is no energy expenditure to maintain that motion. ~ Amatulić ( talk) 18:34, 30 May 2008 (UTC)
what combinations work and do they¿ i know you cant give medical advice, but what does science say so far about the effectivity of them¨¿thnx guys —Preceding unsigned comment added by 75.69.26.8 ( talk) 03:20, 29 May 2008 (UTC)
What jobs and career options are there in relation with animation? —Preceding unsigned comment added by 117.194.225.94 ( talk) 03:55, 29 May 2008 (UTC)
Hi. I saw a '3rd Rock From the Sun' episode where mary albright puts this chemical on dick solomon's desk, because earlier they had been playing impractical jokes on one another. Dick comes in and sits at his desk. as soon as he puts his hands on the desk, they are instantly stuck. Then he uses too much force to get his hands off and he accidently puts his head on the desk and then is stuck to this position. My question is: Can this chemical really do that sort of thing, paste objects together that quickly? Jwking ( talk) 05:32, 29 May 2008 (UTC)
What part of the brain becomes more active during sexual arousal? Or at least, what part controls that. -- 68.90.143.120 ( talk) 06:30, 29 May 2008 (UTC)
I'm curious why the sky is orange during nighttime. First of all it was 10 pm so I discount the sun. It is relatively cloudy and rainy during the night and the clouds are actually the ones that is a dull orange. I live in Manila so the air pollution is strong but I can't account fo r the orange hue as we use fluorescent lamps here rather than oil or fires.-- Lenticel ( talk) 06:58, 29 May 2008 (UTC)
I was wondering how efficient generators are at converting mechanical energy from the rotating magnet to electrical energy? 61.69.132.119 ( talk) 07:32, 29 May 2008 (UTC)
Does anyone know where I could find mortality rates calculated as hazard rates? I'm trying to answer questions like, if a Canadian man makes it to the age of 93, what are his odds of surviving to 94? If an American baby reaches the age of 6 months, what are the odds of her surviving the remainder of her childhood? Thanks. moink ( talk) 12:36, 29 May 2008 (UTC)
I bought some plimsolls online from River Island, but they stink of plastic like they're from some crappy discount shoe warehouse.. I've put them outside to air but they still smell awful. I thought I'd ask you clever lot for some advice. Whack on the Febreze? Air tight container with some Bicarbonate of soda? Thanks in advance! 79.78.46.84 ( talk) 12:57, 29 May 2008 (UTC)
How does one cite matter from a chapter in a book that has contributors that are different from the editors mentioned on the cover and elsewhere? Which all authors are to be included in the citation?
Kindly help me with this doubt.
Thanks in advance.
Regards.
PS: Have posted the same query on the talk page of citations, but am not expecting a quick reply. Thanks.
—KetanPanchal
taLK 13:30, 29 May 2008 (UTC)
Heller, Steven, ed. The Education of an E-Designer. Heller, Steven and Karen Pomeroy. Design Literacy: Understanding Graphic Design.
I've read somewhere that if you're not having a full night's sleep, or if you're just taking a nap, certain sleep durations are better than others because you'll not be waking up during the "wrong" part of the sleep cycle. I think two recommended durations were given in the article I read, one for short naps and the other for longer sleep.
I can't find the article and don't remember what the recommended durations are. Can someone point me to some good articles/resources on the subject? —Preceding unsigned comment added by 71.162.242.15 ( talk) 16:53, 29 May 2008 (UTC)
When measuring earthquakes there are different sclaes, like Mercalli intensity scale and Richter magnitude scale. Why did the Japanese invent their own scale "shindo" ( Japan Meteorological Agency seismic intensity scale) (In Japanese called 震度)? Moberg ( talk) 16:57, 29 May 2008 (UTC)
Under the Nebular Hypothesis, the rotation of the solar system is caused by the contraction of the original cloud and, as it condensed, the rotation went from perhaps once every million years to that which it is today. The principle of the conservation of angular momentum is applied. The question is, however, what caused the original rotation? Any generally accepted reasons for the cause under this hypothesis, or are we still guessing? Boblaw1 ( talk) 17:52, 29 May 2008 (UTC)
What distinguishes the following technologies?
-- 141.161.98.180 ( talk) 18:12, 29 May 2008 (UTC)
what exactly will happen when we short two terminals of a common type of diode ,does there be any charge movement and a resulting effect on depletion region 202.125.143.75 ( talk) 19:25, 29 May 2008 (UTC)
Well I would like to build a switch which is switched on and off by clapping your hands twice. What do I need, and how do I do it? Bastard Soap ( talk) 20:29, 29 May 2008 (UTC)
In the event of a hypothetical doomsday scenario how long would a modern nuclear power plant be able to supply electricity before it shuts down? I know an that nuclear power plant's have some kind of dead man's handle mechanism as a failsafe but let's assume that it was turned off. How long could a modern nuclear power plant work on it's own? For hours, days, weeks or years? Mieciu K ( talk) 21:57, 29 May 2008 (UTC)
We have a page which lists lots of trigonmetric equations. Is there a similar page for physics equations. In particular "v = u + at", "s = ut + 0.5at^2", "F = ma", etc. Maybe also for electrical equations "V = IR" "Q = VC" etc. If it does exist you can't find it by searching for "v=u+at". -- SGBailey ( talk) 22:24, 29 May 2008 (UTC)
I was mulling over how to make demonstration logic gates using many different technologies. Obviously a mechanical AND gate can be made with two input levers which can be up or down pushing on opposite ends of a floating pivoted beam where the central pivot holds a flagpole. If both are down, the pole is down, if only one is up the the beam pivots and the pole is down, if both are up then the beam itself is raised and hence the pole is up. What other technologies are there and how might they be demonstrated? Hydraulic (liquid pressure?); Pneumatic (flow (or not)); electromechanical (relays); electronic (transistors and voltages); Pure optical (no idea how); Magnetic (how?), etc etc. Suggestions and advice on a postcard please... -- SGBailey ( talk) 22:35, 29 May 2008 (UTC)
| | | | | | | | -+----+- -+----+- | | | | | |_________| | \ * * / \ * * / \ * * / \ * * / \ * * / \* */ | | | |
Wiklearn ( talk) 23:42, 29 May 2008 (UTC)How is wind speed related to the height of ocean waves? At what wind speed would white caps appear? Wiklearn ( talk) 23:42, 29 May 2008 (UTC)
Trompes are simple devices that use the power of falling water to compress air. Trompes were used widely in the 19th century. They were used to provide the air for mines, blast furnaces pneumatic tools for alpine tunnel making, etc. The town of Cobalt in Ontario, Canada claims to have the only hydraulic air compressor (Trompe) left in the world http://www.cobalt.ca/ragged_chutes.htm Researchers in England have tried to use low pressure trompes (attached to an enclosed wind turbine and electric generator) to extract energy from the water running over weirs in a cost effective way. (Pdf is available if required). I believe that a dedfinition of trompe would help show people in poor countrys that energy is available from low grade (low head) hydro sources without the huge investment in machinery that is currently a barrier to using these (often high volume) sources of energy. —Preceding unsigned comment added by Gaiatechnician ( talk • contribs) 23:46, 29 May 2008 (UTC) Gaiatechnician ( talk) 23:47, 29 May 2008 (UTC)
Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed". I actually wrote it and my poor effort has been sitting there with that proviso (and doubt) over it for a long time. Just hoping to get it fixed. My sources are long ago photocopys from engineering manuals. I have made some so I know they exist. Gaiatechnician ( talk) 15:04, 30 May 2008 (UTC)
Such devices have existed. Within the last year there was an article in New Scientist showing methods of using low-head flow to compress air. The water flowed in the shape of a U taking air bubbles down to the submerged air reservoir in the middle. The water leaves at a lower level. Polypipe Wrangler ( talk) 10:23, 30 May 2008 (UTC)