No need to put a spin on this science: the physics of slowly spinning soccer ball flight.

http://www.youtube.com/watch?v=a_36rzK_RE8 This paper is pretty awesome. The authors take a commonly observed yet mysterious phenomenon and break it down with some hard-core physics. Turns out that the slow spin seen when a soccer ball flies through the air doesn't depend on how the ball is kicked, because the authors observe the same behavior when the ball is shot out of a machine, or even when dropped straight down. They go on to do a series of experiments, including several involving shooting soccer balls through smoke, and determine that the seams on the surface of the ball are required for the spin, although different sewing patterns don't seem to matter (pun intended).The strange flight behaviour of slowly spinning soccer balls. "The strange three-dimensional flight behaviour of slowly spinning soccer balls is one of the most interesting and unknown phenomenon associated with the trajectories of sports balls. Many spectators have experienced numerous exciting and emotional instances while observing the curious flight behaviour of these balls. We examine the aerodynamic mechanisms of erratic ball behaviours through real flight observations, unsteady force measurements and flow pattern visualisations. The strange behaviour is elucidated by the relationship between the unsteady forces on the ball and the wake flow. The irregular changes in position for twin longitudinal vortices have already been discovered in the supercritical Reynolds number region of a sphere with a smooth surface. This finding is applicable to the strange behaviour of the flight of soccer balls with this supercritical flow. The players, spectators, and television viewers will gain greater insight into the effects of soccer ball flights."