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Perhaps the most popular piece of young adult fiction since the Harry Potter series, Suzanne Collins’ The Hunger Games has been adapted for the screen starring Jennifer Lawrence as Katniss Everdeen and Josh Hutcherson as Peeta Melark. This is the first installment of what will certainly be a series of films set in Panem, a post-apocalyptic version of North America. Twelve districts, known only by their number, are subject to the Capitol, the only part of Panem with advanced technology. Each district must select a teenage boy and girl for the annual fight to the death, known as the Hunger Games. The event is shown on television across Panem as a reminder of the Capitol’s power over the 12 districts.
Katniss Everdeen is from District 12, which provides coal for the rest of Panem, and appears to be Appalachia. Katniss saves her family from starvation after her father dies in a mining accident by learning to hunt just outside the border of the district. She hunts with Gale (played by Liam Hemsworth) and trades meat on the black market. Katniss volunteers to be the “tribute” from District 12 when her younger sister’s name is drawn in the ceremony called the “reaping.” District 12’s male tribute is the baker’s son Peeta, whose main skills seem to be cake decorating and sensing what the public wants.
The film version of The Hunger Games is generally a faithful adaptation of the book, though some details about the unusual animals only appear in the book. The film contains good elements for biology, physical science, and physics teachers to use in the classroom.
The Capitol uses a couple of genetically engineered animals to keep the districts in line. We first learn about “mockingjays,” descendants of mockingbirds manipulated to be able to recall and repeat what they hear people say. In their current form, mockingjays simply repeat short sequences of notes they hear. Katniss is able to use this to communicate with an ally in the midst of the Hunger Games. Another engineered creature is much more immediately dangerous. “Tracker jackers” are a particularly aggressive wasp with hallucinogenic venom, and the ability to home in on specific people. While both of these abilities might seem farfetched, real wasps and hornets use pheromones to communicate when attacking prey and defending their own nest, and the venom of some reptiles is known to cause hallucinations.
Katniss and Peeta are taken from District 12 to the Capitol on a train that can travel at 200 miles per hour, and appears to hover over the tracks, rather than running on wheels. This train resembles a magnetically levitated (or maglev) train, a technology that currently exists, though only a few trains are serving the public at this time. The idea behind maglev technology is to use the repulsion of like magnetic poles to hold the train above the track, and also to propel it forward. This virtually eliminates friction between the train and the track, so wind resistance becomes the dominant factor. One technical challenge facing maglev trains is that the electromagnets strong enough to hold up a train require a lot of energy. If high-temperature superconductors could be developed, they would potentially reduce the energy costs of maglev systems dramatically.
Katniss draws the bow in this publicity still for The Hunger Games.
Katniss developed her archery expertise while hunting with a bow and arrows in District 12. Once she obtains a bow in the Hunger Games, she becomes a much more dangerous competitor. A bow stores elastic potential energy in bending when the archer pulls the string back. When the string is released, the elastic potential energy is transferred to the arrow, giving it kinetic energy. It would be an interesting challenge to ask a high school physics class to estimate the maximum speed at which Katniss’ arrows could leave her bow. I would approach this question by figuring out how much elastic potential energy is stored in the bow, and then how fast an arrow would be going if it had that same amount of kinetic energy. This will significantly overestimate how fast the arrow would actually be traveling, because it assumes 100% efficiency of the transfer of energy from the bow to the arrow. Use this data to get started: Assume the arrow has a mass of 35 grams, and it takes 200 Newtons of force to draw the arrow back 0.75 meters. Elastic potential energy (PE) in the bow is equal to the work done pulling the bow back, and all that potential energy is converted to the kinetic energy (KE) of the arrow:
I assume the bow is an ideal spring, so the force in the spring can be calculated from F = kx, where k is the spring constant of the spring (bow):
So, since work is equal to the integral of F(x)dx—
—we arrive at PE = 75 joules. If the arow leaves the bow with 75 J of KE, how fast will it be moving?
(over 200 ft/s). The immense popularity of both the book and movie versions of The Hunger Games provides a rare opportunity for science teachers to take advantage of biology, technology, and physics topics present in the story.
Jacob Clark Blickenstaff is teacher education programs manager for the American Physical Society. He can be reached at firstname.lastname@example.org.
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