How do you "observe" the position of an electron? Do you use x-rays? If so, what happens when you hit the orbital of a given atom with x-rays? Will it just accelerate the electron(s) out of the orbital? Also, how can you then infer the position the electron had initially occupied? Do you just have detectors set around the bombarded atom? Since you know everything about your fired x-ray (intensity, wavelength etc.), you can solve for the position at impact? EDIT: You probably can't, because which detector is hit by the electron depends on the velocity and position of the electron at impact (neither of which you know). EDIT2: But if you know the temperature of the atom, then do you not know at what velocity the kicked-out electron moves? EDIT3: You only know speed but not the actually direction of motion? Then, when this experiment was repeated a lot of times, the probability density functions were established?