The Motion of Curling Rocks: Experimental Investigation and Semi-phenomenological Description

TL;DR

This study investigates curling rock trajectories through experiments and develops a semi-phenomenological model, providing evidence that supports the wet friction hypothesis and challenges dry friction models.

Contribution

It introduces a semi-phenomenological model for curling rock motion and provides experimental evidence supporting wet friction over dry friction.

Findings

Curling rocks ride on a thin liquid film at the ice surface.

Dry friction models are inconsistent with observed trajectories.

Frictional force opposes motion relative to the liquid film.

Abstract

A large number of curling shots using a wide range of rotational and translational velocities on two different ice surfaces have been recorded and analyzed. The observed curling rock trajectories are described in terms of a semi-phenomenological model. The data are found to rule out `dry friction' models for the observed motion, and to support the idea that the curling rock rides upon a thin liquid film created at the ice surface (i.e. `wet friction'). Evidence is found to support the hypothesis that the frictional force acting upon each segment of the curling rock is directed opposite to the motion relative to this thin liquid film and not relative to the underlying fixed ice surface.