Major League Physics
Dedicated to the learning and teaching of physics through baseball.

Physics of Baseball Activities

This is a basic set of fun activities that explore some of the fundamental physics behind the grand old game. Most of the experiments involve simple and cheap equipment. Only a few of them require any math and they are indicated. They are all pdf files. Please enjoy them and feel free to send feedback to me at the address below.

• The Physics of a of a Baseball in Flight

  The Fall Classic

  All objects feel the effects of gravity even a well-hit baseball. You will learn an important idea about the way gravity works and understand the difference between gravity and air resistance.

  Flight of Fancy

  In the "Fall Classic" experiment, you learned about gravity and how it effects objects that are falling straight downward. Here you will understand how gravity affects a flying object like a lined shot headed for the Green Monster.

  Launching a Homer

  If you want to hit a homerun, you certainly want to hit the ball as hard as possible, but what angle should you launch it for the greatest distance? Do you think the best launch angle for the baseball is 45-degrees? Is it more or less? What about a ping-pong ball? Here is an experiment you can do with a ping-pong ball to see what happens.

  Spin Doctor

  In any professional baseball game you can watch pitchers fool batters with their magic. The magic is done by the "Magnus force" induced by the spin the pitcher imparts to the ball. The Magnus force is exerted perpendicular to the plane defined by the axis of spin and the axis of the velocity of the airflow over the ball.

  Force Play

  This exercise will help you be sure you understand the way forces act on the motion of a ball by asking you to sketch the forces on balls in different situations.

• The Physics of Pitching

  The Itch to Pitch

  Don't you wish you had a major league fastball and a biting curve? You will after this activity!

  In Stitches

  The most "striking" feature of a baseball is the interesting stitch pattern. The stitches have two important uses for pitchers. First, they provide a place to get a better grip on the ball. Secondly, they interact with the air as the ball moves. The stitches slightly affect the air drag, but they strongly affect the Magnus force. Here you will get to learn the how stitches make a difference in the flight of a thrown ball.

  Fun with PitchFX (MATH ALERT!)

  Thanks to a company called Sportsvision and Major League Baseball you can get the initial position, initial velocity, and average acceleration of any pitch thrown in the big leagues. The video technology that tracks pitches is called PITCHf/x. This activity will show you how to calculate many quantities associated with pitches using the kinematic equations.

• The Physics of a Baseball Bat

  Up the Middle

  Why do some bats feel right and others not so much? There are several design features of a baseball bat in addition to its mass and length. They are the center of mass (CM), the center of oscillation (CO), the center of percussion (CP), the moment of inertia (MOI), and the vibrational nodes (VN). All of these affect the feel and effectiveness of a bat. After this activity, you will understand the center of mass (CM) and how to find it for a bat.

  The Game in the Balance

  To understand the next feature of a baseball bat, the center of oscillation (CO), we need to develop a related idea called "rotational inertia." Here's a bit of fun to help you build your knowledge.

  The Perfect Swing

  You will get to understand more about the idea of rotational inertia, by learning how to measure a distance called the "center of oscillation (CO)". The "moment of inertia (MOI)" is a numerical measure of rotational inertia and is directly related to the CO. You will learn to measure the CO of a baseball bat using a baseball pendulum and then calculate the MOI of the bat.

  Quick Reactions

  When the ball hits the bat it exerts a huge force, usually more than one ton! The reaction force on your hands depends upon where on the bat the ball is hit. There is a spot on the bat called the "center of percussion" or CP where you won't feel anything. You will learn to find this spot on a bat.

  Vibrating Bats

  Have you ever hit a ball off the end of the bat and felt the "hand full of bumble bees?" When a bat hits the ball, the bat can start to vibrate. When this happens energy that could go into making the ball go further is used to make the bat vibrate. You'll investigate the nature of these vibrations.

  Silence of the Slam

  In "Vibrating Bats" you learned about the way bats vibrate because of the collision with the ball. In this activity you will learn how to find the vibrational node for an actual baseball bat. The vibrational node will turn out to also have something to say about the "sweet spot."

• The Physics of Hitting

  Off the Wall

  The rules of baseball state a legal baseball traveling at 60mph at a wall of northern white ash must rebound with a speed of 54.6 +/- 3.2% of the initial speed. This number, 0.546, is called the "coefficient of restitution," or COR. You will measure the COR of a superball and a baseball.

  Chill Out

  The COR of a baseball is supposed to be precisely 0.546. However, this value depends not only on the properties of the ball, but also on the temperature and humidity of the ball. This experiment will illustrate the effect of temperature on the COR.

  Bat Performance Factor

  The COR of a baseball slammed against a wall is about 54.6%. Is it the same for a ball hitting a bat? Well, that depends upon the bat. The Bat Performance Factor or BPF is listed on most aluminum bats you buy. You will understand why the rules of many leagues only allow bats with a BPF of 1.20 or less.

  Laying Down A Bunt

  The perfect bunt has been described as "catching the ball with the bat." When you swing a bat, the usual goal is to hit the ball as hard as possible. That is, to have as much momentum as possible go into the motion of the ball. The art of laying down a bunt is about reducing the momentum that the bat gives the ball. This activity will help you understand the physics behind this feat.

  Playing the Angles

  Being able to hit the ball well to all fields is a matter of strength and timing. Compared to a well hit ball up the middle, a right handed batter must swing just a bit later to hit it toward right field and a bit earlier to hit it to left. There is some very basic physics behind this timing that you will explore.

• The Physics of Fielding

  Nice Catch

  You have probably noticed that sometimes when you catch a hard thrown ball in the palm of your glove, it really hurts. Sometimes it doesn't. Have you noticed that when it really hurts, the ball often pops out of your glove? This activity will help you understand the physics of catching a baseball.

  Hit the Cut-off (MATH ALERT!)

  When outfielders chase down a ball hit in the gap, they rarely throw all the way to home plate. Instead, they are taught to throw the ball to an infielder positioned about halfway between them and home. This infielder, called the "cut-off," then throws on to home. You will learn why "hitting the cut-off" is the best play.

• The Physics of Baserunning

  First to Third (MATH ALERT!)

  The runner at first takes off as the batter rips a solid single to right. He's thinking he can make it to third base. What path should he take? He knows that the shortest distance between two points is a straight line, but does that mean he should run directly toward second, make a 90^o turn and head directly for third? Usually runners take a rounded path from first to third. We'll learn which path takes the least time.

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