The motion of a curling rock

Abstract

We present a plausible physical model that accounts for the motion of a curling rock. The principal features of the model are (i) that the kinetic friction induces melting of the ice with the consequence that the curling rock experiences both "dry friction," when encountering solid ice, as well as "wet friction," for contact areas that pass over the thin film of liquid water lying above the ice; (ii) that the wet friction is velocity dependent; and (iii) that the curling rock is able, in its last stages of motion, to drag some of the thin liquid film part way around the rock, which significantly enhances the curl of the rock. We compare the model to actual trajectories of curling rocks.