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bio website marty-green.blogspot.com
location Canada
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Nov
30
comment What is the physical sense of the transition dipole moment?
Why must my errors always be gross and my ideas total nonsense? Can I not be capable of subtle errors?
Nov
30
answered Friction between air and a tube
Nov
30
comment What is the physical sense of the transition dipole moment?
Surely you realize I don't understand any of what you're saying.
Nov
30
comment What is the physical sense of the transition dipole moment?
Don't you think it would be more accurate to call me answer "partial nonsense" rather than "total nonsense"?
Nov
29
comment What is the physical sense of the transition dipole moment?
@Vladimir I'm pretty sure that the approximation is virtually exact in the small-dipole case typified by the s-p transition in Hydrogen. And thanks for the props: I'm not used to people agreeing with me.
Nov
29
answered What is the physical sense of the transition dipole moment?
Nov
20
answered What does it take to understand Maxwell's equations?
Nov
20
revised Calculating the gravitational acceleration inside of a planet
elaboration of very sketchy initial answer
Nov
20
answered Calculating the gravitational acceleration inside of a planet
Nov
15
answered Duality and Fourier Transforms
Nov
14
comment What objective criteria distinguish between valid science, fringe science and pseudoscience in physics?
Not believe in Jim Carr? You might as well not believe in Archimedes Plutonium! (I don't know who wrote the poem from which this line is an excerpt but if you google it you will end up on my blogsite.) Seriously though, amazing article. Loved the stuff about evolution.
Nov
14
comment Desperately Need Help with Grade 9 Static Electricity
But then this doesn't explain why the air doesn't just "ground" the whole PVC pipe. Still, this isn't the first experiment I've tried with static electricity where I seem to get positive charge showing up out of nowhere. I also tried the classic electrophorous, rubbing the styrofoam and putting down the metal plate (powder paint coated!): when I picked up the pie plate (by an insulator), the metal plate was full of positive charge! (It's supposed to be neutral until you ground it. But I didn't ground it.)
Nov
14
accepted Desperately Need Help with Grade 9 Static Electricity
Nov
14
comment Desperately Need Help with Grade 9 Static Electricity
Ron, I'm going to have to give you credit for the correct explanation. It's not that there is a path to ground: I put a new hole in the PVC that just goes to dead air inside the pipe, and the effect is just as strong. When I bring a ground wire near my pipe, it works just like the screw: the crazy dancing around the wire and everything. It works the same if I ground the screw but I don't have to ground it. What I think is that when it comes to positive charge, the air is almost as good as a ground. I think the air has enough surplus positive charges that it effectively grounds the screw.
Nov
13
comment Desperately Need Help with Grade 9 Static Electricity
I'm under a lot of pressure to stick with option 1. But I can't do that. (I didn't mention that I'm a student teacher (I went back for certification at age 55) and it's my first unit on my own.)
Nov
13
comment Desperately Need Help with Grade 9 Static Electricity
Thanks, JB. I don't want to seem ungrateful, but it's AWFULLY strong to be just polarization. And I don't know of any kind of polarization where both ends of the screw have the same charge. I'm pretty sure the whole screw is positive. And yes, I checked the inside of the pipe and if there are charges on it, they don't create any forces. By the way, you previously had an upvote on your answer which is now missing; I just want you to know that it wasn't me who cancelled it.
Nov
13
comment Desperately Need Help with Grade 9 Static Electricity
Thanks, JxB, but I can't accept your answer for two reasons. First, I've seen attraction by induced charge and it's not as strong as direct attraction. This is a really strong force. And when it bounces away, it's also super strong, which is really not characteristic of induced charge. Finally, I just tried the pointy end of the screw inside the PVC pipe. Also positive. So the whole screw has the same charge.
Nov
13
asked Desperately Need Help with Grade 9 Static Electricity
Nov
12
comment Speed Distribution of The Particles
@kso83o I apologize for the ignorance of other people on this site. They should be ashamed of themselves.
Nov
9
comment Photon wave packets from distant stars
Additional for the record: Georg had a series of comments where he ridiculed my explanation, but he has erased them all now.