Physics of Baseball

Physics of Baseball

4.6 6
by Robert K. Adair

View All Available Formats & Editions

A Sterling Professor of Physics at Yale University provides a unique and fascinating perspective on America's favorite pastime.

Did you Know . . .

  • An average head wind (10 miles per hour) can turn a 400-foot home run into a 370-foot out?
  • A curve ball that seems to break over 14 inches never actually deviates from a straight line by more tha 3


A Sterling Professor of Physics at Yale University provides a unique and fascinating perspective on America's favorite pastime.

Did you Know . . .

  • An average head wind (10 miles per hour) can turn a 400-foot home run into a 370-foot out?
  • A curve ball that seems to break over 14 inches never actually deviates from a straight line by more tha 3 1/2 inches?
  • There is no such thing (except in softball) as a rising fastball?
  • The collision of a ball on the bat lasts only about 1/1000th of a second?
  • That a batted ball should be able to travel no father than 545 feet?

Editorial Reviews

New York Times Book Review
Fascinating and irresistible.
Wall Street Journal
An absolutely wonderful compendium of little know fact about the national pastime.
Adair (physics, Yale U. and physicist to the National League, 1987-89) offers the physics and formulae along with examples and anecdotes from pro ball play. If you follow the game, you ought to understand the principles. Annotation c. Book News, Inc., Portland, OR (

Product Details

HarperCollins Publishers
Publication date:
Edition description:
Product dimensions:
5.33(w) x 8.00(h) x 0.40(d)

Read an Excerpt

Models and their Limitations

A small, but interesting, portion of baseball can be understood on the basis of physical principles. The flight of balls, the liveliness of balls, the structure of bats, and the character of the collision of balls and bats are a natural province of physics and physicists.

In his analysis of a real system, a physicist constructs a welldefined model of the system and addresses the model. The system we address here is baseball. In view of the successes of physical analyses in understanding arcane features of nature--such as the properties of the elementary particles and fundamental forces that define our universe (my own field of research) and the character of that universe in the first few minutes of creation-it may seem curious that the physics of baseball is not at all under control. We cannot calculate from first principles the character of the collision of an ash bat with a sphere made up of layers of different tightly wound yarns, nor do we have any precise understanding of the effect of the airstream on the flight of that sphere with its curious yin-yang pattern of stitches. What we can do is construct plausible models of those interactions that play a part in baseball which do not violate basic principles of mechanics. Though these basic principles--such as the laws of the conservation of energy and momentum-severely constrain such models, they do not completely define them. It is necessary for the models to touch the results of observations--or the results of the controlled observations called experiments-at some points so that the model can be more precisely defined and used to interpolate known results or toextrapolate such results. Baseball, albeit rich in anecdote, has not been subject to extensive quantitative studies of its mechanics, hence, models of baseball are not as well founded as they might be.

However connected with experience, model and system-map and territory-are not the same. The physicist can usually reach precise conclusions about the character of the model. If the model is well chosen so as to represent the salient points of the real system adequately, conclusions derived from an analysis of the model can apply to the system to a useful degree. Conversely, conclusions-although drawn in a logically impeccable manner from premises defined precisely by the model-may not apply to the system because the model is a poor map of the system.

Hence, in order to consider the physics of baseball, I had to construct an ideal baseball game which I could analyze that would be sufficiently close to the real game so that the results of the analysis would be useful. The analysis was easy; the modeling was not. I found that neither my experience playing baseball (poorly) as a youth nor my observations of play by those better fitted for the game than I ideally prepared me for the task of constructing an adequate model of the game. However, with the aid of seminal work by physicists Lyman Briggs, Paul Kirkpatrick, and others, and with help from discussions with other students of the game, such as my long-time associate R. C. Larsen, I believe I have been able to arrive at a sufficient understanding of baseball so that some interesting conclusions from analyses of my construction of the game are relevant to real baseball.

In all sports analyses, it is important for a scientist to avoid hubris and pay careful attention to the athletes. Major league players are serious people, who are intelligent and knowledgeable about their livelihood. Specific, operational conclusions held by a consensus of players are seldom wrong, though-since baseball players are athletes, not engineers or physicists--their analyses and rationale may be imperfect. If players think they hit better after illegally drilling a bole in their bat and filling it with cork, they must be taken seriously. The reasons they give for their "improvement," however, may not be valid. I hope that nothing in the following material will be seen by a competent player of the game to be definitely contrary to his experience in playing the game. Honed by a century of intelligent trial and error, baseball must surely be played correctly--though not everything said about the play, by players and others, is impeccable. Hence, if a contradiction arises concerning some aspect of my analyses and the way the game is actually played, I would presume it likely that I have either misunderstood that aspect myself or that my description of my conclusion was inadequate and subject to misunderstanding.

Even as the results discussed here follow from analyses of models that can only approximate reality, the various conclusions have different degrees of reliability. Some results are quite reliable; the cork, rubber, or whatever stuffed into holes drilled in bats certainly does not increase the distance the ball can go when hit by the bat. Some results are hardly better than carefully considered guesses: How much does backspin affect the distance a long fly ball travels? Although I have tried to convey the degree of reliability of different conclusions, it may be difficult to evaluate the caveats properly. By and large, the qualitative results are usually reliable, but most of the quantitative results should be considered with some reserve, perhaps as best estimates.

In spite of their uncertainties, judiciously considered quantitative estimates are interesting and important; whatever their uncertainties, they often supplant much weaker-and sometimes erroneous--qualitative insights. Consequently, I have attempted to provide numerical values almost everywhere: sometimes when the results are somewhat uncertain, sometimes when the numbers are quite trivial but not necessarily immediately accessible to the reader.

As this exposition is directed toward those interested in baseball, not physics, I have chosen to present quantitative matters in terms of familiar units using the English system of measures distances in feet and inches, velocities in miles per hour (mph), and forces in terms of ounce and pound weights. I have also often chosen to express effects on the velocities of batted balls in terms of deviations of the length of a ball batted 400 feet (a long home run?) under standard conditions.

To express the goals of this book, I can do no better than adopt a modification of a statement from Paul Kirkpatrick's article "Batting the Ball": The aim of this study is not to reform baseball but to understand it. As a corollary to the statement of purpose, I must emphasize that the book is not meant as a guide to a player; of all the ways to learn to throw and bat a ball better, an academic study of the mechanics of the actions must be the least useful.

Meet the Author

Robert Adair is Sterling Professor Emeritus of Physics at Yale University and a member of the National Academy of Sciences. His research has largely been concerned with the properties of the elementary particles and forces of the universe.

Customer Reviews

Average Review:

Write a Review

and post it to your social network


Most Helpful Customer Reviews

See all customer reviews >

Physics of Baseball: Third Edition, Revised, Updated, and Expanded 5 out of 5 based on 0 ratings. 1 reviews.
Guest More than 1 year ago
I selected this book for my son, who is sixteen now, because of his skills in math and science, and his interest and ability in baseball. He's listed in the Who's Who of American High School students now. I selected this book for him when he was a little bit younger. As a parent, I like to encourage his abilities, whenever I can. (his brother's, too) I like to think that the early years we spent reading together helped to develop his interests. I know that he enjoyed the book, and that he still has it. He has quite a collection of other books on baseball, too. This is a great book.