What is exactly a wave function of the system. I have been told that wave function is something that is used to describe the wave nature of a particle but how? I could not understand or rather visualize it. And how can the wave function be a complex number or a negative value? For example if the probability for an atom or electron to be in a particular position is 0.25, the wave function can be -0.5 or +0.5. Under what conditions would the wave function have +0.5 or -0.5? And under which conditions can it have a complex value P.S: I dont know most of the quantum mechanics jargons and words, so I would be happy if you can try to explain your replies in simple layman terms.