  We recently introduced a simple toy model to describe energy propagation and
backscattering in complex layered media (T.R. Krishna Mohan and S. Sen, Phys.
Rev. E 67, 060301(R) (2003)). The model provides good qualitative description
of energy propagation and backscattering in real soils. Here we present a
dynamical study of energy propag ation and backscattering in a gravitationally
loaded granular chain and compare our results with those obtained using the toy
model. The propagation is ballistic for low g values and acquires
characteristics of acoustic propagation as g is increased. We focus on the
dynamics of the surface grain and examine the backscattered energy at the
surface. As we shall see, excellent agreement between the two models is
achieved when we consider the simultaneous presence of acoustic and nonlinear
behavior in the toy model. Our study serves as a first step towards using the
toy model to describe impulse propagation in gravitationally loaded soils.
