The Physics of Hockey

What do Wayne Gretzky and thermodynamics have in common? A lot more than you might think. The game the National Hockey League calls " the coolest game on earth" is also a fast-paced, dynamic display of physics in action.

In The Physics of Hockey, physicist and amateur hockey player Alain Hache examines some of the physical principles behind the world's most popular winter team sport. What makes ice so slippery you can skate on it? How can you skate backwards most rapidly? How can physics improve your slapshot? Why do some collisions cause injuries but not others? How does a Zamboni work? And how do you prepare a pure, smooth ice surface in Dallas when it's 90 degrees outside and there are twenty thousand people inside?

This is physics by a hockey fan for the hockey fan. Hache investigates the properties of the ice surface, the science of skating and of skates, the odds of winning and losing streaks, and the principles behind shooting, hitting, and goaltending. Touching on topics such as solid-state physics, statistical physics elasticity, probability, thermodynamics, and mechanics, Hache uses science to enhance our appreciation and understanding of the game. The book is illustrated with photos and graphs and punctuated with anecdotes to show how famous players, past and present, are really physicists on skates.

A thought-provoking, fun, and gentle introduction to some basic issues in physics, The Physics of Hockey is a truly unique book worthy of the shelf of every hockey fan and physics enthusiast.

The book explains just about every imaginable aspect of ice hockey. It explains how the ice rink is created and maintained. It tells us why players skate the way they do, why goalies move the way they do, why the players manipulate their sticks in certain ways, why the bodily protection is needed and how it works and how the game generally proceeds.

Hache's style is quite readable, though the idea of applying physics to hockey seems on the surface to be dry. He clearly loves the game and that comes through in his writing. He is both a scientist and a player, and he skillfully combines both of these talents in one very well-written volume.

For a scientist the book is much more meaningful; however, the book has plenty to offer for non-technical hockey fans. The book mixes very technical analyses and diagrams demonstrating physical principles with very down-to-earth prose that general hockey fans should gain a lot from and really enjoy.

The book's one flaw is the way in which the content was organized. The book starts off with a lot of scientific content before moving into the down-to-earth, non-technical prose. In fact, the first topic treated, the physics of the ice itself, is so esoteric, that even I, an engineer, was almost discouraged from moving past it. I was glad I made it through.

If there's a second edition, I suggest that Hache revise the structure of the book. He should write a version that deals with the physics in a way that demonstrates principles without detailed equations and diagrams. Then he should complete each chapter or section with his more technical treatment of each topic, which the non-technical person can bypass without really losing anything in the translation.

The physics is mainly what is called "mechanics". It involves the forces on skates that propel the players and the effects of friction with the ice. It also explains the movement of a puck, both sliding on ice and soaring through the air, and the impact of players on each other or on the boards in body contact. Hache also discusses ice quality and how it affects the play, and how the design of hockey skates achieves maximum usefulness. We also learn how figure skates and speed skates differ from hockey skates.

The difficulty of getting a puck past a goalie is explained in diagrams showing the effective open area of the net, why a goalie moves as he does in order to minimize this area, and why his equipment is designed as it is. Lots of interesting statistics are presented, such as typical puck speeds, both in standard shooting and slap shots, skating speeds and acceleration rates, and sizes of hockey players as it affects their play. The explanation of how a Zamboni works and what ice maintenance is about in general is also extremely interesting.

The Physics of Hockey is an excellent book. Alain Hache's explanations are current (using many current NHL stars) and very interesting (most hockey fans really have no idea how everything happens on the ice from a scientific standpoint). This is a very engaging book for a technical person, but I think Hache missed an opportunity to achieve a broader appeal with a somewhat different organization of the material.


Brillaintly Written, Fun Applied Science   January 24, 2003
 10 out of 10 found this review helpful

If you like ice hockey and got a B or better in high school physics (and you remember how it happened), this book is a must-have.

Alain Hache is an amateur-league goalie, and a professional physicist. His book analyses all aspects of the game, from the coefficient of friction of ice at different temperatures to the effects of air and gravity on a flying puck after a slapshot.

The book includes references to hockey biographies, medical and physiological papers, and player technique books like "Speed on Skates".

Some reviewers might fault the book for not explaining hockey with only physics; the author uses statistics (to explain witing and losing streaks), and geometry (to explain why goalies come out of the net) in his analysis.

Hache's explanations are well written, and as far as I can tell, technically correct. The author is a student of the game and his reference for it is obvious. For the math hobbyist or amateur physicist who is also interested in hockey, this is a fantastic book.