In physics, do all particles have a particle-wave duality? And if so, what determines whether they behave as a wave, or become a one-dimensional point in space? I'm familiar with the electron double slit experiment, and it's my understanding that when it's not observed, an electron acts as a wave. But when it's looked at, it acts like a single particle. How about hadrons, like protons and neutrons, that are made of quarks. Even though the are composite objects, can they also behave as waves, while containing their constituents? If the act of being observed has no influence on particle-wave duality, then what causes this property? And how does it ultimately effect our perception of reality?