I will present the results of recent experiments with ribbons made of active, "BZ gel". The ribbons "flap", i.e., periodically change their curvature. When confined to a liquid interface, the ribbons periodically "surf" from the center of the container to its walls.We analyze this motion and suggest that it represents a new, generic, type of locomotion; locomotion via curvature mismatch. In the experiments, the fluid interface is curved. When the curvatures of the ribbon and the surface are different, both the ribbon and interface are deformed, a deformation that costs energy. Gradients of this energy lead to forces and torques on the ribbon and to its motion. We solve the equation of motion and successfully compute the trajectories of the active ribbons.Our model suggests that such motion could occur in purely solid systems. Specifically, it allows a flexible sheet, which is confined to curved (flexible or rigid) surface, to propagate without applying tangential forces. The possible relevance of this model to "curvotaxis", the phenomenon in which cells propagate and orient themselves in correlation with the substrate curvature, will be discussed. students whom are interested with a personal meeting, (The registration is limited to 5 participants) ( if you are interested in personal meeting please register)https://forms.gle/vfr9a2K3fYyKfx3d7 FOR THE LATEST UPDATES AND CONTENT ON SOFT MATTER AND BIOLOGICAL PHYSICS AT THE WEIZMANN, VISIT OUR WEBSITE: https://www.biosoftweizmann.com/
