What keeps electrons spinning around their nucleus?
in [Relativity]
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From: Ken Muldrew on 31 Mar 2005 13:54 jmfbahciv(a)aol.com wrote: >In article <3avtadF6bq14rU1(a)individual.net>, > "robert j. kolker" <nowhere(a)nowhere.net> wrote: >> >>jmfbahciv(a)aol.com wrote: >>> they can't teach science because there is only 1 microscope/ >>> 10 students. That's an awfully high ratio even though the >>> ads want you to think that it's too low. When I went to >>> high school, I estimate the ration to be 1/100. >> >>While the relative scarcity of lab equipment > >1 in 10 is not a scarcity. I would call it wastage. You're forgetting the undisciplined nature of today's schoolchildren. The worst that can happen to them for misbehaving is they go on holiday for a while. 1/100 microscopes will turn into 0 working microscopes and 1/100 broken microscopes within the first week of classes. And although this situation creates a niche for a useful and productive course in scientific instrumentation (where the students could fix all the broken stuff), such a course will never appear in a modern high school. Ken Muldrew kmuldrezw(a)ucalgazry.ca (remove all letters after y in the alphabet)
From: PD on 31 Mar 2005 14:21 jmfbahciv(a)aol.com wrote: > In article <3avtadF6bq14rU1(a)individual.net>, > "robert j. kolker" <nowhere(a)nowhere.net> wrote: > > > > > >jmfbahciv(a)aol.com wrote: > > > >> > >> The Mass. board of education is now trying to add science > >> as part of the high school graduation requirement. The > >> year proposed was 2008 but news broadcasts are now saying > >> it can't happen until 2010. Listen for the whinging from > >> teachers' unions. One of them is already running ads that > >> they can't teach science because there is only 1 microscope/ > >> 10 students. That's an awfully high ratio even though the > >> ads want you to think that it's too low. When I went to > >> high school, I estimate the ration to be 1/100. > > > >While the relative scarcity of lab equipment > > 1 in 10 is not a scarcity. I would call it wastage. > > > .might impact the quality of > >lab based science instruction there is no shortage of blackboards or > >overhead viewscreen devices. The theoretical aspects of physics and the > >associated mathematics can be taught with the material resources > >currently at hand. > > > >On the other hand biology and chemistry does not a substatial laboratory > >practice component to be taught properly. If one does not dissect the > >worm or frog one has no sense of the asymmetry of internal structure of > >complicated organisms. > > Each student does not need biology and chemistry lab equipment > 7x24. A class of 30 use the lab for 45 minutes at a time. Multiply > by number of classes per day. ...although I have been noticing that > the school buses are now dumping kids at 14:15 lately. That means > that a kid gets 4 hours of class? > You are right, of course, but you assume that students in a classroom will be doing different things at different times, which means that the teacher must orchestrate and monitor at least two different activities simultaneously. This is often unrealistic and results in bedlam. A science class is a plenary experience and not a parallel experience, by default, *unless* someone is very creative and structured with a curriculum that supports parallelism. As any conference organizer can tell you, it is exponentially harder to arrange parallel sessions than plenary sessions. This is where things begin to bog down with teachers. PD
From: PD on 31 Mar 2005 15:57 TomGee wrote: > Tom Capizzi wrote: > > "TomGee" <lvlus(a)hotmail.com> wrote in message > > news:1112061355.884198.62110(a)g14g2000cwa.googlegroups.com... > > > > > > PD wrote: > > > SNIP > > > > > > Centrifugal forces don't exist. They are mistakes of perception and > no force > > actually pushes out. > > > > > Not so. The inertial force of a mass wants it to go straight but the > gravitational force wants it to turn and if an orbit results the net > force is on the side of gravity but just enough to pull it into orbit. > > >> > > >> > > >> If this comes as a shock to you, perhaps it's because > > >> you're relying on the physics you learned in the 3rd grade. > > >> 3. In circular motion, you'll note that the velocity is tangent to > > > the > > >> circular trajectory, perpendicular to the radius of the circle. > Both > > >> the true, centripetal force and the false, centrifugal "force" are > > >> along the radius of the circle, perpendicular to the velocity. > > >> > > >> > > > Velocity is a vector but you are using it to mean "direction". > Speed > > > cannot be tangent nor perpendicular to anything, so you're babbling > > > now. > > > > Talking about yourself again? Vector: > > 2. (Math.) A directed quantity, as a straight line, a force, or a > velocity. > > Vectors are said to be equal when their directions are the same their > > > magnitudes equal. Cf. Scalar. [1913 Webster] > > > > > That's what I said, velocity is a vector. It is also "speed", but that > is not what he means. You, apparently, have no idea what I mean. Velocity is a vector with both a magnitude (the magnitude is synonymous with speed) and a direction. This vector can most certainly lie tangent to the trajectory and I have no idea why you think this is nonsense. Moreover, a force, which is also a vector with both a magnitude and a direction, can most certainly be perpendicular to the velocity. I hope this clears things up for you. > If he is saying that the forces are imposed > perpendicular to the speed, if he means to use velocity for speed, that > would be nonsense, as I noted above. If he means to say that the > direction of the mass quantity is tangent to the path of the object > (trajectory), that too makes no sense. > > > > > > >> There is > > >> no way that a force that is perpendicular to the velocity can > change > > >> the magnitude of the velocity, nor does it help in any way to > > > maintain > > >> the velocity. > > >> > > >> > > > Mygawd Im talking to a child! There is no magnitude in velocity! Um...really? A velocity is a vector with both magnitude (speed) and direction. > It > > > is a measure of the rate of change of position of something wrt > time, > > > speed, and direction. > > > > See above definition of vector. Clearly it has magnitude. You don't > know > > what you are talking about again. > > > > > If magnitude and quantity had the same meaning, we would have use for > only one and not both. Good lord, you really mean that? No room for synonyms in your "common language" definitions? Suppose you look up both magnitude and quantity in your Encarta. > > > > > > > >> 4. Newton's 1st law should also have been taught to you in 3rd > grade > > >> physics, and you should be reminded that, even in the absence of > > >> forces, objects in motion tend to stay in motion. > > >> > > >> > > > I can't believe you are so ignorant as to claim that the 2nd law > allows > > > objects to remain in orbit if all forces are removed. I let that > > > foolishness go by the first time you said it, to keep from making > you > > > look sillier, but it is you who brings that onto yourself, not me, > with > > > your absurdities. > > > > Look again. It says 1st law. If you actually read the 1st law you > would know > > that it says motion "in the same direction", that is to say a > straight line, > > unless acted on by unbalanced forces. > > > > > If you actually understood what is being said you would know circular > motion is not a straight line. Or do you agree with Silly there that > objects in circular motion, orbits or orbitals, will continue in such > motion even when the forces maintaining them in such motion are > removed? Nor is that what I said. A net force on an object will change an object's velocity. This means it might change the velocity's magnitude only, or its direction only, or both. In the case of circular motion, the centripetal force affects the velocity's direction, not its magnitude. > > >> > > >> > > >> Now, if you find any of this to be intuitively wrong, then your > > > problem > > >> is not with special relativity, it's with 3rd grade physics. If > you > > >> would like corroboration that any of the above is true or false, > then > > >> simply itemize the thing you think is wrong and ask the newsgroup. > > >> > > >> > > > All but a few have dared to agree with me or disagree with you, > but, as > > > I said in my first post in this thread, I find it incredible that > the > > > first 8 posters could not answer a simple question properly. > Either > > > they all think you're the greatest thing since Einstein or they > will > > > agree to anything so long as they don't have to agree with me. > > > > > > > The question was what keeps the electron spinning around the nucleus, > not > > what keeps it attracted. Maybe they are the same thing to you, but > they are > > actually perpendicular directions. In physics, perpendicular > components, > > even of the same vector, are independent. If you wanted to know what > > attracts the electron, you should have asked a better question. Of > course, > > it seems you already had the answer you wanted, but were trying to > bait a > > troll's trap. > > > > > Hey, I did not ask the questions. You seem to think that the question > was what keeps it moving? It was not. He asked what keeps it moving > _around the nucleus_, as you correctly state above. I see, so you read the original poster's subject line, but did not bother to read the content of his message? Dig through your archives and find out what he really said. Or is it impossible for you to keep more than 7 words in your head at one time? PD > You don't seem to > see the distinction between those two questions, but that is not my > fault. Something keeps free electrons moving, and as free electrons, > they are not then moving around any nucleus. Since the question was > that specific, so was my answer. > > TomGee
From: PD on 31 Mar 2005 16:14 TomGee wrote: > Tom Capizzi wrote: [snip] > > > > > > > The question was what keeps the electron spinning around the nucleus, > not > > what keeps it attracted. Maybe they are the same thing to you, but > they are > > actually perpendicular directions. In physics, perpendicular > components, > > even of the same vector, are independent. If you wanted to know what > > attracts the electron, you should have asked a better question. Of > course, > > it seems you already had the answer you wanted, but were trying to > bait a > > troll's trap. > > > > > Hey, I did not ask the questions. You seem to think that the question > was what keeps it moving? It was not. He asked what keeps it moving > _around the nucleus_, as you correctly state above. You don't seem to > see the distinction between those two questions, but that is not my > fault. Something keeps free electrons moving, and as free electrons, > they are not then moving around any nucleus. Since the question was > that specific, so was my answer. In case you don't remember the original post: Nick asked: ===================== What is the velocity of an electron in a shell? Can they move at different speeds and remain in the same shell? More imporatant is what sustains them in their perpetual motions? Mitch -- Light Falls -- =====================
From: TomGee on 31 Mar 2005 17:28
Tom Capizzi wrote: > "TomGee" <lvlus(a)hotmail.com> wrote in message > news:1112244079.328719.15960(a)f14g2000cwb.googlegroups.com... > > > > Tom Capizzi wrote: > >> "TomGee" <lvlus(a)hotmail.com> wrote in message > >> news:1112061355.884198.62110(a)g14g2000cwa.googlegroups.com... > >> > > >> > PD wrote: > >> > > SNIP > >> > >> > >> Centrifugal forces don't exist. They are mistakes of perception and > > no force > >> actually pushes out. > >> > >> > > Not so. The inertial force of a mass wants it to go straight but the > > gravitational force wants it to turn and if an orbit results the net > > force is on the side of gravity but just enough to pull it into orbit. > > Inertial force only exists in the rotating frame. Inertia causing a body to > move in a > straight line is a property of a non-rotating frame, as such straight lines > appear > to be curves in a rotating frame. You're mixing frames of reference. > > So you say, but saying so don't make it so, remember? Or did you forget again? Talk is cheap but support requires heavy labor. Cite something (and no websites unless they make the same claim you make above plus the explanation for it which you failed to provide above. Why should the inertial force of the 1st law be excluded from rotating frames, in view of thefact that Newton makes no such distinction. > >> >> > >> >> SNIP > >> >> > >> >> > >> > Velocity is a vector but you are using it to mean "direction". > > Speed > >> > cannot be tangent nor perpendicular to anything, so you're babbling > >> > now. > >> > >> Talking about yourself again? Vector: > >> 2. (Math.) A directed quantity, as a straight line, a force, or a > > velocity. > >> Vectors are said to be equal when their directions are the same their > > > >> magnitudes equal. Cf. Scalar. [1913 Webster] > >> > >> > > That's what I said, velocity is a vector. It is also "speed", but that > > is not what he means. If he is saying that the forces are imposed > > He is saying exactly what he means: the radius of the circle is at right > angles > to the velocity (vector). It is inappropriate to claim anything is > perpendicular > to speed. > > Of course. That's what I said. > > SNIP > > > perpendicular to the speed, if he means to use velocity for speed, that > > would be nonsense, as I noted above. If he means to say that the > > direction of the mass quantity is tangent to the path of the object > > (trajectory), that too makes no sense. > > Makes sense to me. At any given point on the trajectory of any object the > direction is defined to be the tangent at that point. > > I won't belabor this point any further, but he said, in effect, that the object moves in the direction which the object moves. > >> > >> SNIP > > >> > > If magnitude and quantity had the same meaning, we would have use for > > only one and not both. > > Since you want to quibble about definitions, what in Gee-speak do you claim > is the difference? Besides, have you never heard of synonyms? > > Why is it okay for others to use synonyms in physics but not for me to use them? In physics it is the finer points which seem to win the day, they tell me. If you want to know the difference, look them up yourself and then let me know. > >> > >> > > >> >> 4. Newton's 1st law should also have been taught to you in 3rd > > grade > >> >> physics, and you should be reminded that, even in the absence of > >> >> forces, objects in motion tend to stay in motion. > >> >> > >> >> > >> > I can't believe you are so ignorant as to claim that the 2nd law > > allows > >> > objects to remain in orbit if all forces are removed. I let that > >> > foolishness go by the first time you said it, to keep from making > > you > >> > look sillier, but it is you who brings that onto yourself, not me, > > with > >> > your absurdities. > >> > >> Look again. It says 1st law. If you actually read the 1st law you > > would know > >> that it says motion "in the same direction", that is to say a > > straight line, > >> unless acted on by unbalanced forces. > >> > >> > > If you actually understood what is being said you would know circular > > motion is not a straight line. Or do you agree with Silly there that > > objects in circular motion, orbits or orbitals, will continue in such > > motion even when the forces maintaining them in such motion are > > removed? > > You misrepresent what others say and expect agreement on your error? > > I do not misrepresent what others say. What they say is in black and white for all to read. You disagree with me so you claim I am misrepresenting what others say. If I did that, aren't you smart enough to show others where I have done that? > >> >> > >> >> SNIP > >> > > >> > >> The question was what keeps the electron spinning around the nucleus, > > not > >> what keeps it attracted. Maybe they are the same thing to you, but > > they are > >> actually perpendicular directions. > > SNIP > > >> it seems you already had the answer you wanted, but were trying to > > bait a > >> troll's trap. > >> > >> > > Hey, I did not ask the questions. You seem to think that the question > > was what keeps it moving? It was not. He asked what keeps it moving > > _around the nucleus_, as you correctly state above. You don't seem to > > see the distinction between those two questions, but that is not my > > Your error. I explicitly pointed out that the two questions are different > above. > > You did? Why? I already did that. Do you think the OP did not want to know what keeps it moving around the nucleus? Why did he ask that then? > > > Earlier you made a spurious claim about speed when the poster specifically > used the term velocity. > > No, I did not. You misunderstood what I said. I said that using speed was inappropriate if he meant that definition of velocity, and you agree to that. > > > Below you make reference to the irrelevant "free > electron". Nobody is talking about free electrons but you. > > Yes, because I am using them to make my point which shows you/he misunderstood the question from the gitgo. > > > > fault. Something keeps free electrons moving, and as free electrons, > > they are not then moving around any nucleus. Since the question was > > that specific, so was my answer. > > > TomGee |