Light: Particle or Wave?

Classically, light can be thought of in two ways: either as a particle or a wave. But what is it really? Well, the "observer effect" makes that question kind of difficult to answer. So before we get too far into it, what is the observer effect?

Simply put, the observer effect is a principle that states simply observing (or measuring) something can change its value. This effect is vastly more important in quantum mechanics than in everyday life, though it appears in a great many places. This means that - like most things in the quantum world - the phrase “what you see is what you get” doesn’t really apply. Therefore measuring what light is, in a way, can defeat the purpose. However the observer effect does very nicely explain why we have made tests that conclusively prove that light is a particle, and we have made tests that conclusively prove that light is a wave. Logic dictates that it can’t be both...

Or does it? Read more; http://www.fromquarkstoquasars.com/light-particle-or-wave/

Image Credit: Douglas Hofstadfter