I have a few problems understanding the double slit experience and the behavior of photos due to simple observation. I am not really looking for in depth explanation here (great if you have it) but more for links or references to read more about it. Here are some questions: 1. What does "observation" mean? Is it mere act of looking passively or is something interfering with the photon such as shining light on it during observation? 2. Observation is made at the slit, and at the board after the slit. When observed it acts as a particle and when not observed it acts as a wave. Does this imply something about "time" or am I missing something else?