re: Heisenberg's principle
From:
http://www.aip.org/history/heisenberg/p08.htm
The uncertainty relations may be expressed in words as follows.
The simultaneous measurement of two conjugate variables (such as the momentum and position or the energy and time for a moving particle) entails a limitation on the precision (standard deviation) of each measurement. Namely: the more precise the measurement of position, the more imprecise the measurement of momentum, and vice versa. In the most extreme case, absolute precision of one variable would entail absolute imprecision regarding the other.
The more precise the measurement of position, the more imprecise the measurement of momentum, and vice versa.
Sounds like common sense to me, if I want to measure the precise position of something, then that something must be motionless. If I want to measure the exact quantity of momentum, then there must be motion involved.
But such a impossibility of knowing the two events simultaneously does not negate the understanding of the structure of electrons or atoms.
Johannes