I was reading about the double slit experiment that proved the wave and particle nature of electron. I read that electrons give a diffraction pattern when they are not observed (wave nature) and passes through the slits separately like particles when they are observed.
My doubt is, how does the electron understand that it is being observed? What is forcing it to behave as a particle when we make an observation?
Best Answer
"how does the electron understand that it is being observed?“
Your statement is based on the assumption that "being observed“ is a completely passive process. But that is not the case.
Let’s rephrase your question: how does the electron understand that it is being detected. Well, that’s a simple one: because it interacts with the detector! This interaction causes the electron to behave differently compared to the situation when it is not detected.
In contrast to our everyday terminology, observation always requires some form of interaction. “Seeing” the electron yourself seems not to require any other detector than yourself. But again this is not the case: it requires shining a light (shooting photons) on the electron that is bounced of (interact with) the electron to reach your eye. In reality you are not the detector; you are only part of a detector. The other part is the light source and the photons interacting with the electrons.