  The dynamics of a spring-block train placed on a moving conveyor belt is
investigated both by simple experiments and computer simulations. The first
block is connected by spring to an external static point, and due to the
dragging effect of the belt the blocks undergo complex stick-slip dynamics. A
qualitative agreement with the experimental results can only be achieved by
taking into account the spatial inhomogeneity of the friction force on the
belt's surface, modeled as noise. As a function of the velocity of the conveyor
belt and the noise strength, the system exhibits complex, self-organized
critical, sometimes chaotic dynamics and phase transition-like behavior. Noise
induced chaos and intermittency is also observed. Simulations suggest that the
maximum complexity of the dynamical states is achieved for a relatively small
number of blocks, around five.
