@thesurfgraduate: I recently saw some explanation for dummies of Young's double slit experiment. If I understand correctly the act of measuring or observing electron change it's behaviour. So my question is: What does exactly observation mean in this experiment? Does the observer have to be alive or intelligent? What if we measure the electron's behaviour and store it on some hard drive but no one will look at these results and then this hard drive will be broken? And finally did any scientist try to test this (like storing but not reading measurments) ?