The ability to make a ball swerve through the air rather than follow a straight line is a valuable one in
many sports, whether as a pitcher in baseball, a spin bowler in cricket or a footballer taking a penalty.
The curve occurs because of the ‘Bernoulli effect’, which was discovered by scientist Daniel Bernoulli.
When the player wants to make the ball follow a curve through the air, he makes it spin as it leaves his
hand or foot. As it spins, air is pulled with it through friction, and this works together with the current
created by its motion trough the air. On one side of the ball, the air passing it and the air spinning
around it go in the same direction, allowing it to move faster, while on the other side of the ball, the air
spinning around it is in the opposite direction to the air current passing the ball, which slows it down
and makes it curve.