In the previous chapter we considered the shape of steady-state condensates, either homogeneous or confined by trapping potentials. We have seen that the condensate described by the GPE is a special kind of fluid, similar to the idealized Euler fluid without viscosity that appears in classical fluid dynamics textbooks. Not surprisingly for a fluid, the dynamics of the condensate exhibits a variety of interesting time-dependent phenomena. This includes sound waves to shape oscillations, which we explore in this chapter. Excitations in the form of solitons and vortices are explored in later chapters.