  We construct a simple two-phase equation of state intended to resemble that
of compressed baryon-rich matter and then introduce a gradient term in the
compressional energy density to take account of fintie-range effects in
non-uniform configurations. With this model we study the interface between the
two coexisting phases and obtain estimates for the associated interface
tension. Subsequently, we incorporate the finite-range equation of state into
ideal or viscous fluid dynamics and derive the collective dispersion relation
for the mechanically unstable modes of bulk matter in the spinodal region of
the thermodynamic phase diagram. Combining these results with time scales
extracted from existing dynamical transport simulations, we discuss the
prospects for spinodal phase separation to occur in nuclear collisions. We
argue that these can be optimized by a careful tuning of the collision energy
to maximize the time spent by the bulk of the system inside the mechanically
unstable spinodal region of the phase diagram. Our specific numerical estimates
suggest cautious optimism that this phenomenon may in fact occur, though a full
dynamical simulation is needed for a detailed assessment.
