Insultingly Stupid Movie Physics Read online

  © 2007 by Tom Rogers

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  Rogers, Tom

  Insultingly stupid movie physics : Hollywood’s best mistakes, goofs, and flat-out destructions of the basic laws of the universe / by Tom Rogers.

  p. cm.

  ISBN 978-1-4022-1033-4 (trade pbk.)

  1. Motion pictures--Miscellanea. 2. Physics--Miscellanea. I. Title.

  PN1998.R569 2007

  791.43--dc22

  2007033901

  Printed and bound in the United States of America.

  VP 10 9 8 7 6 5 4 3 2 1

  To the world’s physics and engineering teachers, who on a regular basis stand before an often difficult crowd and share their passion for the subject. To Dr. Thomas Thorpe, whose high school lecture opened my eyes when he demonstrated momentum by knocking the podium on the floor. And to the best teacher I ever had, Professor P. K. Stein.

  CONTENTS

  Acknowledgments

  Introduction

  Chapter 1: The Noble Cause: Striking a Blow for Decency in Movie Physics

  Chapter 2: Moviemaker Mathematics: How Hollywood Shoots from the Hip

  Chapter 3: Conservation of Mass and Energy: Is Anything Sacred?

  Chapter 4: Scaling Problems: Big Bugs and Little People

  Chapter 5: Inertia and Newton’s First Law: Why Blowing Up Spacecraft is a Bad Idea

  Chapter 6: Newton’s Third Law: That Special Hollywood Touch

  Chapter 7: Creative Kinematics: Explosive Entertainment

  Chapter 8: Hollywood Bombs: How Filmmaker Physics Misses the Boat

  Chapter 9: Leaping Logic: Why Moviemakers Say “How High”When the Director Says Jump

  Chapter 10: Acceleration and Newton’s Second Law: How to Get Started, Use Brakes, or Change Direction, Hollywood Style

  Chapter 11: High-Energy Films: Nuclear Firecrackers, Falling People, and Cars as Weapons

  Chapter 12: Movie Momentum: The Attractive Force of Glass, Rail-Gun Recoil, and Cosmic Toyotas

  Chapter 13: JFK and Momentum: Hollywood’s Conspiracy to Assassinate History

  Chapter 14: Scenes with Real Gravity: Celebrating Disasters with Happy Hollywood Endings

  Chapter 15: Scenes with Artificial Gravity: The Good, Bad, and Ugly Space Stations

  Chapter 16: The Movie Merry-Go-Round: How Filmmakers Create Ridiculous Spin

  Chapter 17: Hollywood Disasters: Global Warming, Tsunamis,Tornadoes, and Other Big Winds

  Chapter 18: The Moviemaker’s Cookbook: Cigarettes as Lighters, Exploding Cars, Burning Bugs, and Other Recipes for Foolishness

  Chapter 19: Wars versus Trek: Forgiving versus Forgetting

  Chapter 20: All-Time Stupid Movie Physics Classics: “They Said the Physics Were Impossible …”

  Notes

  Index

  About the Author

  Acknowledgments

  Few large projects get done without the support of others and this book is no exception. My son Scott was invaluable for his many insightful suggestions in the preparation of the book. He patiently read and edited my drafts repeatedly. Likewise, without the tireless support of my wife and soul mate Sandy, I could not have succeeded. Not only did she repeatedly proofread the developing manuscript, she was also a constant source of positive support. My son Mark and daughter Kelly also provided numerous suggestions, as did Bill Burns.

  Introduction

  Contrary to the notion that art should resist the intrusion of science, this book steadfastly maintains that the art of moviemaking should embrace the science of physics, because at a gut level people understand physics better than is commonly believed. (Does any living soul not have first hand experience with force, acceleration, velocity, gravity, etc.?) What’s more, with a little study and reference materials like this one, it’s really not all that hard to understand basic physics at an intellectual level.

  In spite of its esoteric reputation, physics books are actually fairly popular—the science sections of bookstores are full of them. People are fascinated by cutting-edge topics such as string theory, black holes, dark matter, and the weirdness of quantum physics. Oddly, it’s the more straightforward classical physics that often gets ignored, even though it’s extremely useful and the foundation of almost everything in modern science and technology.

  Once again, this book breaks with the norm by concentrating almost exclusively on the commonplace physics principles taught in just about any good high school physics course. Even though many of these physics principles date back hundreds of years to the time of Newton (his major work, Philosophiae Naturalis Principia Mathematica, was published in 1687), they are still incredibly relevant and fascinating in their own right.

  Yes, there are equations and calculations inside for the mathematically inclined, and as a tool of understanding for physics students taking introductory courses. Hopefully, the book will give them a deeper appreciation of the subject. For the budding filmmaker or science fiction writer, the book is filled with all kinds of useful details. However, most of the calculations and heavier technical detail are enclosed in boxes so that the casual reader can skip over them. Extra detail that does not require a mathematical background is enclosed in shaded boxes, again for easy scanning.

  Those who spend some time with the book will learn to see movies more clearly, understand the world around them better, and hopefully have a lot of fun in the process.

  CHAPTER 1

  THE NOBLE CAUSE:

  Striking a Blow for Decency in Movie Physics

  IT’S ONLY A MOVIE

  “It’s only a movie,” is often spoken by fans in defense of flicks with flaky physics, as though reviewing movies for physics content is an insult. But isn’t the fact that Hollywood thinks they can feed us stupid physics the real insult? Let me explain why reviewing movies for something they need is not insulting, or unnecessary—starting with a hypothetical. Imagine a football movie: a group of plucky individualists have been forged into a team by the tough yet big-hearted coach. No one gave them a chance; yet, here they are in the big game playing their hearts out as Murphy, their beloved teammate, lies in the hospital with bandaged eyes, listening to the contest via radio.

  The team is behind and desperate. It’s the seventh down in the eleventh quarter, so they punt a touchdown pass from the 127th yard line. But wait, this isn’t football. It’s nonsense. Anyone with football knowledge would think it was ridiculous; some would be offended. The scene would never appear in a movie— not because it’s unlikely or hackneyed, but because it’s unthinkable to take artistic license with the rules of football. (For those who don’t favor American-style football, substitute basketball, soccer, hockey, or just about any other team sport. With a few modifications, the plot will still work.)

  Artistic license isn’t a driver’s lice
nse; it’s an ambulance license. It grants the right to break rules without suffering petty penalties like traffic tickets. But rule breaking can cause errors, leading to serious penalties: wrecks. Rule breaking requires care; it’s not a good idea unless there’s a good reason. Hollywood would never take such a gamble with the manmade rules of football. So, when it comes to something profound like the guiding rules of the universe, why, of course, break the rules at will—no risk here.

  Okay, I realize that Hollywood isn’t likely to reform, but at least by discussing bad movie physics it’s possible to repair some of the damage done to our clear thinking by constant exposure to foolishness. Sadly, Hollywood has a rational reason for affording more respect to the rules of football than the laws of physics: audiences are more likely to know them. Ironically, movies may be part of the cure for this ailment: Hollywood’s bad physics examples are good physics teaching tools. Besides, movies are almost as entertaining as physics, so what could be more fun than combining the two?

  In 1997, after years of watching one Hollywood physics wreck after another, I took a stand for decency in movie physics by founding what has become the premier movie physics site on the Internet. Since American moviegoers are used to rating systems warning of possible affronts to their sensibilities from strong language, violence, and sexuality, and since warning systems are, of course, highly effective deterrents, how could I resist? I created a similar system to warn about affronts from bad physics. Well, maybe ratings aren’t so effective but at least they’re fun.

  Movie Physics Rating System

  GP = Good physics in general

  PGP = Pretty good physics (just enough flaws to be fun)

  PGP-13 = Children under 13 might be tricked into thinking the physics were pretty good; parental guidance is suggested

  RP = Retch

  XP = Obviously physics from an unknown universe

  NR = Unrated. When a movie is obviously a parody, fantasy, cartoon, or is clearly based on a comic book, it can’t be rated but may still have some interesting physics worth discussing.

  THE IMPACT ON ARTISTIC QUALITY

  To understand when the rules (the laws of physics) should not be broken, it’s best to start with the situations where they can or should be. These include cartoons, parodies, and fantasies. Even top-notch science fiction routinely stretches the boundaries of physics for the sake of story.

  Time-travel is a good example of acceptable physics-bending for the sake of story. Ask ten physicists about time travel and you’ll get eleven different answers, and that’s with two abstaining. The truth is nobody really knows for sure if it’s possible, let alone how to do it. Without it, however, there would be no Terminator movies, a definite loss of some great cinematic moments (not to mention catchy gubernatorial campaign slogans).

  In The Terminator [PGP] (1984), computers/machines have developed consciousness and a need for entertainment along with it. What to do: work a few math problems—for a computer, how mundane—or kill off humanity? It’s a no-brainer: kill people. Unfortunately, those irascible humans are unenthusiastic about extinction. A human leader steps forward and pulls together an effective resistance movement.To remedy this affront, the machines send a terminator—a metal robot covered with living tissue (Arnold Schwarzenegger)—back in time to assassinate the resistance leader’s mother and snuff the movement before it starts.The humans, somehow, get wind of the plot and send back one of their own to protect the mother. Both protector and terminator arrive naked since, according to the movie, anything nonliving has to be surrounded by living tissue in order to be transported backwards through time. (Evidently hair, dead skin, and fingernails are the exception.)

  Okay, the business about having to surround metal with living tissue and only send naked people back in time has no scientific basis, but it’s necessary for the film’s central conflict. If the human could carry a futuristic weapon, he could easily blow away the terminator and spoil the fun. Instead, he’s a rabbit desperately trying to avoid the jaws of a bloodthirsty wolf in possibly the highest intensity chase ever filmed.

  The nakedness also taps into the deepest levels of the human psyche. Imagine arriving naked, not just at work or school but in an entirely different era. The moviemakers do the arrival scene right: they depict a gray area of physics, time travel, with a minimum of scientific mumbo-jumbo and considerable artistic purpose.

  It’s another matter to defy well-established physics principles for no good reason. Any bright high school physics student (probably not a target audience) can easily spot such foolishness. Many people feel it—like an annoying itch—even when they have no physics background whatsoever. They may not be able to verbalize reasons but have experienced gravity, velocity, acceleration, force, and energy firsthand their entire lives. Individuals with military experience—shooting guns, setting off explosives, flying helicopters—are especially cranky about the itch. Here’s a scary thought: in spite of physics’ reputation for difficulty, it’s really not all that hard to learn; verbalizing soon follows.

  Guidelines for Safe Movie Physics

  1) Never break laws or principles taught in high school or first year college classes unless the movie is obviously a:

  Parody

  Fantasy—including cartoons

  Comic book adaptation

  Keep in mind that most of these physics principles have been around for decades—some for centuries. Lots of people know about them.

  2) It’s okay to occasionally stretch physics knowledge beyond its current boundaries when all of the following four conditions are met:

  The stretched area of physics is not fully understood and is at least remotely possible.

  The story cannot be done without the stretch and the stretch creates unique entertainment or artistic opportunities.

  The stretch is explained with a minimum of scientific mumbo jumbo.

  The stretch does not obviously contradict the first law of thermodynamics (see Chapter 3).

  People do at times watch movies for mindless entertainment, but they also watch to vicariously expand their experience. It’s like gaining an additional lifespan. For about two hours they can be a criminal, a saint, a drugged-out loser, or a charismatic genius without all the messy consequences. Movies provide emotional release. Vicariously blowing up an evil emperor’s death star helps release the pent-up emotions from not blowing up a discourteous driver’s SUV. Oddly, even a total fantasy must seem real. Moviemakers know this and go to great lengths in such areas as set and costume design to give the illusion of reality.

  The Passion of The Christ [NR] (2004), depicting the crucifixion of Jesus, was a box office hit at least partly for this reason. For example: fake beards were applied meticulously one hair at a time. Had moviemakers applied beards the way they apply physics, the hair would have been drawn with magic markers— phosphorescent orange ones just to make sure the whiskers were exciting.

  Its not that filmmakers are neglectful or unappreciative of movie physics—never. They love it, to the point of creating movie physics’ very own body of clichés: exploding cars, flashing bullets, visible red laserbeams, gasoline lit with cigarettes, and so forth. These serve the cause of movies almost as well as verbal clichés serve the cause of literature.

  While they last, clichés are a filmmaker’s joy but eventually get moldy and have to be tossed. Tora! Tora! Tora! [PGP] (1970) carefully depicted the bombing of Pearl Harbor and was awarded an Oscar® for best visual effects, along with four other nominations including one for sound. The sound track used copious quantities of canned ricochet noises—which sound fake to anyone who has heard real bullets ricochet—but then the fake sounds were a standard movie physics cliché.Today, these sounds have been updated. Movies like Saving Private Ryan [GP] (1998), which depicted the D-Day battle with realistic bullet-sounds, have ruined this cliché’s chance for a comeback.

  Since successful movies require the feeling of reality, why would any moviemaker allow indecent physics into his
or her film? The tools to do it right—such as computer generated imaging (CGI) software with realistic physics algorithms—exist. But generating excitement in action scenes with realistic physics takes more time and thought because it imposes more constraints.With less freedom in special effects, moviemakers might be forced to— gasp—work harder on acting, plot, and dialogue.

  THE DANGER TO CLEAR THINKING

  Artistic perfection is a worthy goal, but the real reason for improving movie physics is the fact that many people actually believe it, even as they say, “It’s only a movie.” The foolishness works its way into our collective knowledge as fact, reinforcing major misconceptions of physics along the way. These have to be unlearned before the subject can be mastered. Okay, learning physics may not be at the top of everyone’s to-do list, but it is rather helpful for designing cars, computers, refrigerators, television sets, and all the bazillions of other items modern society is based on.

  Hollywood moviemakers are masters of making audiences see only what they’re supposed to believe. Take the case of the reader who wrote to set me straight about, arguably, the most famous vehicle “jump” ever, in Speed [PGP-13] (1994).