Second Term Paper

Science Fact or Cinematic Fiction?

The movies employ a variety of special effects and techniques which utilize real world physics for the stories that they tell. Certain stories require special circumstances in which the characters find themselves. Sometimes the things which happen in the movie world does not match the physics of the real world. The cinema does the best it can to make us believe in the worlds they create. They do not want us to question, but rather to believe in the movie world as being real. Some movies are more successful at this than others, though.

One principle of physics which is not always done right is that of action and reaction forces. Along with that concept comes the forces involved in jumping and landing. There are certain rules in regard to acceleration, force, and timing which go into these actions. For different reasons, these rules are not always followed in the movies. One of the easiest physical actions to see this in is the jump.

We see an example of a jump in Star Wars Episode 1. During the fight between Darth Maul and Obi-Wan and Qui-Gon, Obi-Wan makes a 40-50 foot jump. He gets kicked off a ledge and then jumps back up to a higher platform. The gap is a considerable distance away. His push time for his jump is about one second, or twenty-four frames. Using the formula relating push time with jump magnification and jump time, I found that his correct push time would be about four or five frames.

A jump is affected by three forces: that of gravity, the supporting force of the floor, and the frictional force of the floor. In order for someone to jump, they need the reaction force of the floor to oppose the downward force of their feet. This resistant force must be greater than the force of gravity and the resistance of their weight. In order for Obi-Wan to jump as high as he did, he would need to generate a great amount of force. He would have to push on the floor with a force six times his weight. This kind of force is only generated in a short period of time, and a long push time does not create a greater amount of force.

The opposite holds true instead. The greater the acceleration or force, the shorter the push time. In order for him to credibly make that jump in the film, he would have to generate a force of about nine hundred pounds. His push time would be about four to six film frames, all to take him forty feet in the air. What does work in this scene is the fact that he uses his arms to generate force. He swings his arms before lifting off the ground, which is in line with the rules of body mechanics. He also spends half of his time in the top quarter of the jump arc. Both these things are believable physics.

Another film which displays a jump in a very cinematic way is the Matrix. In this film Morpheus makes a jump across the space between two skyscrapers. In the film his jump magnitude is about thirty, his jump time is about four seconds, and his push time is about one second. What does not work in this sequence is his push time. Assuming all other factors are correct, for the height and time of that jump his correct push time would be one to two frames.

This is an even bigger jump than Obi-Wan's and it requires a larger amount of force to be applied to the ground. Based on estimates from the film, Morpheus would have had to generate about five thousand, seven hundred pounds- or about thirty times his body weight. The time is not short enough in the push to show how great a force he generated. Also, the film does not reveal that his jump force is this great by the effect he has on the ground. If he had generated this amount of force, it would have made an effect on the cement roof he was standing on.

Morpheus's landing on the other side is more accurate, however. It shows him landing and cracking the cement of the other building's roof. In a jump, the landing force is very similar to the pushing off force. So the effect of the land would mirror the effect of the jump. Given that much force, it is plausible that Morpheus would damage the surface he landed on. But this movies does not accurately show the force he would need in taking off. It also does not portray the push time accurately. If the correct push time were there, the audience would not be able to see what was going on. One or two frames would not be enough time for the audience to catch the action. It would go by too fast for anyone to see.

There are a lot of special circumstances with physics in the movie Spiderman 2 as well. In one scene, Spiderman is swinging in the air and loses his power to shoot webs. He falls about 300 feet, from the height of a skyscraper. He lands on a couple of aluminum air ducts. His fall is approximately three seconds. The timing of this fall seems believable for the height at which Spiderman falls. However, the force with which he lands would seem to be greater than implied. He only slightly dents the air ducts, when in reality he would have created more damage. Because the air ducts are hollow, they slow down the impact time which makes the fall safer. However, with such a great force of the fall, the metal would not be able to maintain its shape with its resistance force.

For a pulling action, a person would need the opposing force of the floor and the friction of the ground to help them pull. If not using the ground, they would need the opposing force of their own body- an opposing action or body part. This force would need to be greater than the weight, friction, and inertia of the object being pulled.

An example of is in the bank scene in Spiderman. When Doc Oc is robbing the bank, Spiderman throws a table at him with his webs. He knocks Doctor Octopus through the bank window and into a cab. Doc Oc, who weighs about two hundred pounds, flies about twenty feet in the air. The force needed to knock him like that would be about four thousand pounds. This force was created by the pull of Spiderman's arm holding the web, the opposing force is generated by his other arm. Assuming his muscles could generate that type of force, the time at which he does the action does not demonstrate this. In the same way a shorter amount of push time creates a greater force for a jump, so would Spiderman need to create a greater force in a shorter time period. The table does not accelerate fast enough to create as great a force required to knock Doc Oc twenty feet.

For each of these examples there are cinematic justifications for their physical errors. In Star Wars, the physics are presented as being different from our world, or at least some characters have exceptions. The Jedi are a group who are able to master and bend the physical laws of the universe. For that reason, it seems believable that Obi-Wan is able to make that jump even if it does not follow reality's physical laws.

As for the Matrix, it too has characters who bend the laws of physics. They breaking of natural laws and actions is used to demonstrate the power of the characters. The directors could have made Morpheus jump with a physically accurate jump. However, for the sake of clarity his push time was slower. In order to have an accurate push time for that jump the audience would not have been able to see it. The real push time would have actually seemed unnatural.

And Spiderman's fall was scaled back in order to make him seem more durable. If the director put more damage at the end of Spiderman's fall, the audience might have thought that he might be dead. The director lessened the damage created to give the effect that Spiderman didn't receive as much damage from the fall. Lastly, the scene with Doc Oc was used to show the strength and power of the characters. If the table accelerated too fast, the audience might not have caught it or understood it. The main point of the scene was to show the superhuman power of Spiderman.

All the bending of these physical properties and laws served to tell the story of these movies. Sometimes following the laws of physics helps to make the cinematic world believable. At other times, bending them or breaking them serves to define who the characters are. And in other circumstances disobeying the physics of a situation actually can make a scene more believable to an audience.