Rebounding droplet
Figure 3. A water drop falling on a super-hydrophobic surface. Its full trajectory is revealed in this long-time-exposure photograph and shows the drop rebounding fully some 20 times. The vertical scale of the picture is 1 cm and the drop is 1 mm in diameter. The very high elasticity of the rebound is limited by the vibrations of the fluid after each shock. These vibrations can be seen by the ripples in the lines of light that trace out the drop's flight. The vibrations and rebounds between two impacts are eventually damped by the liquid viscosity. (Picture credit: D Richard)