History & Physics of Baseball                                                                                        Goldstein & Kellar

Physics of Baseball Activity

Directions:  View Physics of Pitching Slide Show, fill in the "Putting Something on the Ball" notes outline, and then participate in the "Thrown for a Curve" activity below.

One important difference between a fastball, a curveball, a slider, and a screwball is the direction in which the ball spins. Generally speaking, a ball thrown with a spin will curve in the same direction that the front of the ball turns. If the ball is spinning from top to bottom (topspin), it will tend to nosedive into the dirt. If it's spinning from left to right, the pitch will break toward third base. The faster the rate of spin, the more the ball's path curves.

In this activity, you will to partner up with another person.  Get a styrofoam "baseball" from your teacher. Practice the following pitches and note the direction the ball travels (i.e. floats up, drops down, curves left, curves right)

Curveball: "Choke" the ball (wedge it down between your thumb and forefinger), and cock your wrist to the left; the ball snaps down and to the right on release. The resulting pitch should drop and curve to the left.

	Screwball: Throw the ball like a curveball, but reverse the wrist action and spins. Cock the wrist initially to the right and "turn the ball over" to the left as you throw it. The ball should break down and to the right.
	Slider: Throw the ball like a football pass, with the wrist cocked at a 90 degree angle. The ball should curve slightly down and to the left.