Schrödinger developed what is known as Schrödinger equation. This equation states that there is a wave associated with any particle (like the electron), and it is called the wavefunction and it is spread out to fill the whole universe.
What does all of that mean in plain English?
There is a fortune teller lady called Schrödinger equation who can predict and describe precisely and deterministically the quantum state of the particle.
So actually collapse of the wave function is equivalent to saying that we can know where things are, only when we are actually looking at them. Blink and they are gone!
Lady Schrödinger equation tells us too that particles are like shy people. Their behavior depends on whether or not we are looking at them.