Thread: The Observer Effect View Single Post
Mentor
P: 11,605
The Observer Effect

 Quote by Dr.Todd I keep seeing references to the observer effect in the double -slit experiment where the a of observing the photon or electron going through the slits causes a collapse of the wave function. so, instead of getting a cool interference pattern, you get the pattern expected if the light was acting as a particle.
Actually, you get (or are supposed to get) the single-slit diffraction pattern, which still depends on the wavelike behavior of light. More precisely, you get two such patterns, one from each slit, superimposed on each other. But the spacing between the slits is normally much smaller than the "width" of the single-slit pattern from each slit, so the two patterns almost coincide.

(I don't have any references to experimental evidence at hand. I just wanted to clear up what would be expected.)