Water molecules at the pond’s surface travel primarily vertically up and down as ripples pass. This vertical displacement is a common feature of wave motion, in which particles oscillate about their equilibrium position along the direction of wave propagation.
In addition to the vertical motion, water molecules also experience circular motion about an equilibrium position. This circular motion is particularly noticeable in the case of surface waves like ripples on water. Each water molecule moves in a circular path as the wave passes through, with the center of the circle being the equilibrium position. This circular motion is a result of the wave’s energy spreading outward in all directions.