I'm working through the first few chapters of my QM textbook, so I am not yet familiar with the Schrodinger equation. Consider a free particle, say an electron, moving through free space. I have done the calculations, and concluded that the wavepacket must spread -- that is, get wider. However, this does not make sense to me. How can the wavepacket spread with time? That is, why doesn't the wavepacket just translate? Then I realized that if the wavepacket just translated, we could determine the particle's momentum from its translation. My questions: What does the spreading of the wavepacket with time represent? Would spreading appear to both an observer at rest and a non-relativistic observer in motion? Why does the "hump" in the packet flatten out as time goes on? (I know the mathematics, but I'm not sure what it represents.) Am I right in assuming that the momentum wave function [tex]\phi(k)[/tex] is constant with respect to time? Thanks for your assistance.