From what I understand, there are two phenomena at play, often mixed together. The observer might interfere when it tries to measure (the observer effect, which

From what I understand, there are two phenomena at play, often mixed together. The observer might interfere when it tries to measure (the observer effect, which is true to any system), but there's also an inherent uncertainty on the way waves are measured (the uncertainty principle). The observer effect is well-understood, there's nothing magical about it. For example, a multimeter acts a (very small) resistor, affecting the circuit it's measuring. Sometimes the error you introduce can be ignored, but get unmanageable when you try to measure really small systems, where things are more easily disturbed. The uncertainty principle, on the other hand, is something else. There's a video that I think explains the uncertainty principle well, with a practical example (it's explaining why there's a limit to how many pulses you can send down a fiber optic and still be able to measure on the other side): http://youtu.be/0OOmSyaoAt0?t=7m28s http://youtu.be/0OOmSyaoAt0?t=7m28s