- #1
physics_head
- 4
- 0
Coulomb's law says that the electrostatic force between two electric charges is given by the formula:
Ke*q1*q2/r^2
So, what I want to know is:
1. How did he figure out that Ke was equal to 1/(4*pi*electric constant)?
I mean, I know he used a torsion balance to perform measurements in his experiments. But there undoubtedly would have been error in his measurements, so it seems to me that it would be impossible for one to infer that pi was part of the parameter he was trying to infer the value of. I would have thought that he might conclude that it be 1(4*3.3*electric constant)...or to even infer such an exact value for a critical parameter in the formula at all given the error infested measurements of his experiments...How did he get such an exact value?
2. I don't know the exact details of how he did his experiments. But it seems to me that he probably measured the distance between two charges and the force between them to create a datapoint (distance i, electrostatic force i). and did this with particles at many different distances to create a dataset, and then perfomed a kind of statistical regression to fit a function to the data set...To me, this kind of procedure would seem to be unjustified, since the formula applies to particles of any distance apart, yet the measurements in his experiments could not have contained distances larger than a room. So that means for large distances, we are extrapolating when we use the formula, and a tenant of statistics is that would should not extrapolate. But the formula is supposed to be exactly accurate, without regaurd of the distance right?...so How is this justified? and If he used an alternative procedure different than the one I describe, how did he do it?
It seems mysterious how the structure and parameter values in the formula were figured out...
Ke*q1*q2/r^2
So, what I want to know is:
1. How did he figure out that Ke was equal to 1/(4*pi*electric constant)?
I mean, I know he used a torsion balance to perform measurements in his experiments. But there undoubtedly would have been error in his measurements, so it seems to me that it would be impossible for one to infer that pi was part of the parameter he was trying to infer the value of. I would have thought that he might conclude that it be 1(4*3.3*electric constant)...or to even infer such an exact value for a critical parameter in the formula at all given the error infested measurements of his experiments...How did he get such an exact value?
2. I don't know the exact details of how he did his experiments. But it seems to me that he probably measured the distance between two charges and the force between them to create a datapoint (distance i, electrostatic force i). and did this with particles at many different distances to create a dataset, and then perfomed a kind of statistical regression to fit a function to the data set...To me, this kind of procedure would seem to be unjustified, since the formula applies to particles of any distance apart, yet the measurements in his experiments could not have contained distances larger than a room. So that means for large distances, we are extrapolating when we use the formula, and a tenant of statistics is that would should not extrapolate. But the formula is supposed to be exactly accurate, without regaurd of the distance right?...so How is this justified? and If he used an alternative procedure different than the one I describe, how did he do it?
It seems mysterious how the structure and parameter values in the formula were figured out...