what is the magnus effect on a ball

  The spin of a ball comes from something known as the Magnus effect. The Magnus effect gets it's name from a German physicist, Heinrich Gustav Magnus, who researched and described the effect back in 1852. However, the effect had already been pointed out and correctly described by Isaac Newton, long before Magnus was even alive. The ball is sent into a spin by the player, who's foot collides in such a way that the friction of the shoe on the ball gives it rotational motion, as well as forward motion. The spin of the ball deflects airflow in the direction the ball is spinning. Because the air velocity is faster along one side of the ball, it creates decreased pressure on that side, something known as Bernoulli's Principle. This creates a turbulence behind the ball, and also causes the air to exert an unequal force on the ball (as compared with the opposite side of the ball.) This creates an arc in the ball's trajectory, placing a perpendicular force in the direction to it's motion.