Science Fact or Cinematic Fiction?

Burning Physics: Combustion in the Movies

Since the very beginnings of human culture, we have been obsessed with fire. Heat is essential to comfortable living for human beings, and fire is an essential life-giving source of heat and also exciting, unpredictable and dangerous. It is no surprise then, that heat and fire are central effects in cinema, and seem almost essential to any action film. However, Hollywood often abuses the true physics of fire to create an image that is more compelling for audiences. Often, these abuses are subtle and do add to the entertainment value of the film. However, these glaring faults in physics on a base level separate viewers from the reality of the story, especially in films that otherwise keep a very sober tone. These problems in representing heat span across many genres of films, though the primary offenders are action and adventure films. Sky Captain and the World of Tomorrow, a 2004 film made in a manner referencing classic pulp films of the 40's and 50's shows some classical misuse of heat physics in its character's behavior around a heat ray gun. Volcano, a 1997 disaster flick about a volcano popping up in L.A., has many inconsistent dealings with the heat and lava of the titular volcano. But even No Country for Old Men, a dramatic, somewhat slow paced action drama, includes a common movie explosion that is physically unlikely. These are only a few examples of the failure of movie makers to consider physics in their movies, though it is difficult to deny the thrill in an explosion, with proper physics or not.

Sky Captain and the World of Tomorrow is a film that uses a tremendous amount of special effects. This 2004 homage to classic pulp films with Jude Law, Gwyneth Paltrow and Angelina Jolie is an interesting visual spectacle, though not exactly a major box office success. Jude Law plays the protagonist, Sky Captain, the leader of a band of mercenaries flying World War II era fighter planes in defense of a world that seems right out of the Superman cartoons of the 1920's. Gwyneth Paltrow plays the requisite love interest and aggressive female reporter Polly Perkins, a staple of the genre. The physics in error come not from the major characters, but Sky Captain's best friend and technical genius, Dex, played by Giovanni Ribisi. Dex spends the majority of the movie figuring out the enemies plans, building secret weapons for Sky Captain, and even, in a deviation from the stereotype, getting kidnapped. However, in Dex's first appearance on screen, he is working with some kind of ray gun. No one would complain about the physics of the ray gun itself, the circular white rings spraying out of the elliptical device are just as campy as they ever were in Flash Gordon, but that is not the error in the scene. Dex tests the device on a block of Iron or Steel, which melts like butter under the gun's ray. Dex then walks over to the block and sticks his face right next to it without protection. Iron and Steel start melting at about 2500 degrees Fahrenheit, and the speed of the melting implied this block was hotter than that. While it may not have been fatal, it is inconceivable that Dex wasn't at the very least uncomfortable, but the film takes no efforts to convey that. So Dex is apparently more than just a technical genius, but impervious to heat.

In the late 1990's there were a series of Volcano-related disaster movies, that were a large part in the popularization of the disaster movie genre. Volcano, with Tommy Lee Jones and Anne Heche. Tommy Lee Jones plays a disaster management official, Michael Roark, who has a snarky romance during the disaster with geologist Amy Barnes, played by Anne Heche. While the idea of a volcano popping up in the middle of Los Angeles is far fetched to begin with, Volcano is well known for its utter disregard of earth science in it's presentation. However, there are also quite a few misrepresentations of heat in the movie, though one might expect that from a movie that involves people fighting back against lava. In a climactic moment midway through the movie, the survivors and rescue workers have dammed a river of lava with concrete freeway dividers, and they call in helicopters to pour water on the lava, so that it will crust and self dam the rest of the lava. With triumphant music blaring, the helicopters swoop down pouring thousands of gallons of water onto the lava. Billows of steam pour off the surface of the lava as the heroes cheered to celebrate their victory. However, it is fortunate that this was a movie, because this exact moment would result in screams not cheers. The water hitting that lava would cause the steam pouring off it to be extremely hot; so hot that it would likely scald to death anyone immersed in it. So all of those policemen and firefighters, Tommy Lee Jones and Anne Heche would all be seriously injured or killed by their own plan. But thankfully, the director chose to not kill all of the major characters, and the story continued on. Also, later on in the movie, a character heroically leaps into lava to throw an unconscious man to safety. After jumping into the lava, he not only does not light on fire, but stays standing melting from the ankles up. This and other physics errors may mar the reality of the movie, but that does not stop Volcano from being a favorite of many disaster movie fans, and a classic of the genre.

Although it has a few action scenes and involves quite a bit of violence, No Country for Old Men does not really deserve the title of “action movie”. The deep characterization and introspective nature of the film, as well as the themes of identity and fate that thread through the story are more reminiscent of a dramatic film. However, the plot of the movie nonetheless is the story of an assassin attempting to hunt down and kill the protagonist who has stolen a bag full of drug money. The assassin, Anton Chigurh, played by Javier Bardem and the sheriff chasing him, played by Tommy Lee Jones are truly the central characters of the movie. Anton's twisted ideas of fate and humanity, reflected by his use of coin flipping to decide if people live or die, as well as a cattle killing bolt driver to kill his victims is distinctive. And that is played against the moral quandaries of the aging Tommy Lee Jones, on his last case before retirement, to create the true tension of the film, despite the backdrop of an action plot. Although a much more serious and dramatic film than the first two examined, No Country still plays the Hollywood card in its dealings with heat and explosions. In a scene featuring Anton, he sets a cloth on fire stuffed in the gas nozzle of a car. The ensuing explosion provides a distraction so he is able to steal from a pharmacy. Though this seems a common occurrence in movies, the simple fact is that dropping something on fire into a gas tank will not necessarily cause a car to explode. Gasoline requires a significant amount of oxygen to react enough to cause a powerful explosion. So the only way the car would explode is if it was almost empty and it had just been turned off, so the gasoline was mostly mixed with the air in the tank. So even a movie not inundated with special effects can be sloppy in its use of physics.

These movies incorporate several genres, from a classic pulp sci fi movie, a disaster movie, to a serious dramatic action movie. All of them also have varying levels of believability, from laser guns and robots, to just a simple car explosion. And yet all of them have changed the physics of heat to suit the story. From humans that can handle thousands of degrees comfortably, steam that cools instantly, to mysterious explosions, the errors cover many different aspects of heat. And yet, all of those scenes are compelling, exciting, and riveting to audiences. Even without physical realism, fire, heat, and explosions captivate our attention. But anyone who has seen fire in person, from sparklers to wildfires to explosions, it is not necessary to break physics to show the power and beauty of heat. Movie makers could benefit from incorporating the real physics of fire into their movies, as the real stuff is just as seductive. However, even minus realistic physics, I will always gasp at a great explosion.