Action Reaction

Grade Levels: 5 - 7

Objectives

• Students will learn that the body directly affects the action of an object.
• Students will learn that the spinning action of a ball in flight will be directly related to how it was thrown or struck.

Materials

• Whiffle balls, golf balls, tennis balls
• Plastic bats, golf clubs, pickleball paddles, tennis rackets

Procedures

Notes: Demonstrate each action for the class prior to letting students experiment. Explain the importance of this knowledge in playing various sports; for example, a slice or hook in golf, a curve ball in baseball, a drop shot in tennis.

1. Discuss with students that the physical laws of nature tell us that for every action there is an equal and opposite reaction. This applies to throwing or striking a ball during many physical activities.

   Baseball:

   When a batted ball is hit on the lower half of the bat, it will have back spin, causing it to go up and to the rear. Demonstrate by taking a whiffle ball and striking it with your hand on the bottom, moving forward. Which way does it spin?

   When throwing a ball, if you use a throwing motion that puts a right-hand spin on the ball it will curve to the right; left-hand spin will curve to the left. Demonstrate by taking a ball, placing it on the floor, and rolling it with a spinning motion; watch it curve.

   Golf:

   When a ball is hit with a right-hand spin (clockwise) it will slice, turn to the right; left-hand spin will hook the ball, turn to the left. These actions are caused by the way the club head makes contact with the ball. Show that an "outside-in" swing will put a clockwise spin and cause a slice, and an "inside-out" swing will put counterclockwise spin on it and cause a hook.

   Racket Sports:

   The position of the racket face can be compared to the palm of the hand making contact with the ball if the player were not holding a racket. The direction in which the racket face is moving is the direction of flight the ball will take. If the racket face is "closed," the ball will go the left for a right-handed player. If the racket comes over the top of the ball, putting top spin on, the ball will go downward.

   Demonstrate by striking a ball slowly with the hand and watching the direction in which the ball travels.

   Bowling:

   If you put a clockwise spin on the ball, it will curve to the right; a counterclockwise spin will curve to the left. Demonstrate by rolling a bowling ball approximately 25 feet with different spins. Ask students what spare combinations would require different spins to complete.

2. After providing several demonstrations, give the students an opportunity to practice some of the action-reaction experiments. As you move about the room, ask what other activities students can think of that will demonstrate this concept. Students can demonstrate their knowledge by making a class presentation and demonstrating the effects of motion on an object.

Excerpted from P.E. Teacher's Complete Fitness & Skills Development Activities Program.