"This is Ground Zero. This is my site … I can fix this."—Will Smith as Col. Robert Neville in I Am Legend.

In this column I will examine I Am Legend, which was released on DVD March 18, 2008. This is the third film adaptation of the 1954 Richard Matheson novel. Earlier versions are The Last Man on Earth (1964) and The Omega Man (1971). The current version presents the scenario that a few years in the future a viral cure for cancer will mutate into a disease that wipes out most of the population of the planet.

The virus is spread through the air and through contact with blood, and it kills 90% of those infected. People or animals that survive the initial infection are transformed into a sort of zombie/vampire hybrid (called Darkseekers) that are intolerant of light and eat whatever meat they can find. A tiny fraction of the human population has a natural immunity to the virus and so are not infected at all. Will Smith portrays a military scientist, Colonel Robert Neville, who is immune and is trying to find a cure to save humanity.

You might wonder what science lessons could be learned from a zombie movie like I Am Legend. Other authors have explained how to survive zombie attack more fully than I will in this column, but Col. Neville provides some guidance for science students who find themselves among the last survivors of a zombie pandemic. Some of his tricks are quite useful, others need some modification to fit with how physics and biology actually work.

1. Take advantage of your understanding of simple machines. Early in the film, Col. Neville builds a trap to catch one of the infected using a heavy generator as a counterweight. When the trap is sprung, a slipknot traps the infected’s foot, and the falling generator lifts her off the ground and holds her upside-down in the air. While the colonel is to be commended for applying his physics knowledge in a novel situation, I must take issue with the details. The single pulley system he uses can only change the direction of the force; it cannot multiply the force or the distance traveled. So when his counterweight drops 10 meters, it could only move the trapped zombie 10 meters. In the film, the snare end moves at least twice as far as the counterweight, and it continues to move after the generator has fallen to the ground. The principle is sound, though, and as such it is used again later in the film, though not by Neville. A word to the wise: some zombies paid attention in physics class.

2. If the zombies attacking you have elevated heart rates and body temperatures, you might be able to simply wait them out. The Darkseekers pursuing Col. Neville have a core body temperature of 106°F and a resting pulse of 200 beats per minute. This indicates a very high metabolism, so they would need to eat a lot of food to simply stay alive. Using the mortality numbers from the film, and the population of Manhattan before the outbreak, approximately 150,000 infected would have survived. The action of the film occurs three years after the outbreak, but we see herds of deer, lions, and many birds populating New York. It seems unlikely that all those Darkseekers could have lived so long without hunting the deer to extinction. With such hyperactive zombies, if you can stay hidden long enough they will likely finish each other off before they get to you.

3. Do not put your trust in Col. Neville’s antibodies to cure you. A significant portion of the film depicts Neville’s attempts to isolate an antibody from his blood to return infected people to normal. He runs trials on zombie rats first, and then tests the most promising substances on infected humans he captures alive. Neville’s work could produce a vaccine, since antibodies prevent us from becoming infected. His antibodies would be no help at all once infection has occurred. (I am not the first to note this problem in the film.) To treat someone with an active virus, you need antiviral drugs that disrupt the ability of the virus to replicate.

I am Legend provides science teachers with an opportunity to talk about epidemic or pandemic disease, viruses moving from one species to another, and how vaccines work to prevent but not cure infection. The fact that the infected are extremely sensitive to ultraviolet (UV) light could also be used to discuss sunburn and skin cancer risk later in life. Physical science or physics teachers can show how a pulley system could actually be used to lift a small object through a large distance. Finally, teachers might also hold a discussion on scientific ethics, as Col. Neville kills dozens of rat and (formerly human) zombie subjects in his attempt to find a cure for the virus—a virus that was created through genetic engineering of an existing dangerous pathogen.

Jacob Clark Blickenstaff is Assistant Professor of Physics and Assistant Director of the Center for Science and Mathematics Education at the University of Southern Mississippi. He can be reached at jacob.blickenstaff@usm.edu.

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