Download Comic books first entered my class in 1995, while I was writing an

JAMES KAKALIOS
THE UNCANNY PHYSICS OF SUPERHERO COMIC BOOKS
FEBRUARY 15, 2004
This talk will describe a Freshman Seminar class I teach at the University of
Minnesota entitled “Physics of Comic Books”, where all of the illustrations of physics
principles come from the four-color pages of superhero comics. Comic books get their
science right more often than one would expect. Of course, nearly without exception the
hero’s superpowers themselves violate the laws of nature as we understand them. But
once you grant the characters a one-time “miracle exception”, what follows in the story is
often surprisingly consistent with known physics principles.
For example, in the early days of Superman comics, the Man of Steel could not
fly. Rather, he could only leap great distances, since gravity on Earth is much weaker
than on his home planet Krypton. What sort of force would Superman need to exert to
leap a tall building in a single bound? And what does this imply about the gravity on
Krypton? Using Newton’s Laws of Motion, we calculate that to clear a 30 story building,
Superman’s leg muscles must provide a force of nearly 6000 pounds while jumping.
Presumably his legs are that strong since they are able to support his weight against the
larger gravity on Krypton. We then consider how one can build a planet with an Earthlike surface but with a much larger gravitational attraction. It turns out to be harder than
one might think. The only way to make a planet with such a high gravity involves adding
neutron star material to the planet’s core, which also makes it unstable. And thus we see
why Krypton exploded!
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I was able to find examples in superhero comic books of the correct descriptions
of basic physical principles for a wide range of topics, including Classical Mechanics,
Electricity and Magnetism and even Quantum Physics. Other questions considered in the
class include:

Is it possible to read minds like Prof. X of the X-Men?

If Spider-Man’s webbing is as strong as real spider’s silk, could it support
his weight as he swings between buildings?

Can the mutant master of magnetism Magneto levitate a person using the
iron in their blood?

If you could run as fast as the Flash, could you run up the side of a
building or across the ocean, and more importantly how frequently would
you need to eat?
Once the physical concepts such as forces and motion, conservation of energy, electricity
and magnetism and elementary quantum mechanics are introduced to answer these and
other questions, their real-world applications to automobile airbags, cell phones,
nanotechnology and black hole formation are explained. The students in this class ranged
from engineering to history majors, and while not all comic book fans, they all found it
an engaging and entertaining way to learn critical thinking and basic physics concepts.
Comic books first entered my classroom in 1995, while I was writing an exam for
a Freshman Physics class on the topic of conservation of momentum. I was trying to
come up with some novel twist on the old chestnuts of dropping masses from towers that
hadn’t been worked into the ground (so to speak) and might actually interest the students.
It occurred to me that the story of the death of Gwen Stacy, Spider-Man’s girlfriend, from
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the June 1973 Amazing Spider-Man # 121 afforded just such a problem. Knocked off a
bridge tower by the evil Green Goblin, Gwen fell to her apparent doom until stopped at
the last instant by Spider-Man’s webbing. Nevertheless it was revealed in the story that
she had in fact died. After calculating that her speed was 95 miles per hour at the base of
the bridge, the principle of conservation of momentum tells us that a force of over 10g’s
is necessary to suddenly stop her. Consequently, it is not at all unreasonable that her
neck would have snapped when the webbing stopped her.
My experiences with my Freshman Seminar class motivated me to write a short
piece on the physics underlying the death of Gwen Stacy that was published in the
Minneapolis Star Tribune newspaper Friday May 3, 2002, the same day that the SpiderMan motion picture was released. A copy of this essay is attached. With a big budget
superhero movie opening, I thought there might be interest in a physics professor
analyzing the physics behind a Spider-Man story, and moreover demonstrating that the
science was correct. As one of my colleagues put it at the time, whenever you can
discuss Newton’s second law of motion in the newspaper, you should jump at the chance.
The interest generated by this story and a University press release about my class
was a bit overwhelming, at least for this mild-mannered physics professor. Interview
requests came in from as far away as France and South Africa and as close to home as
PHYSICS TODAY and PEOPLE magazine. And I didn’t have to do anything illegal!
Most gratifying of all were the hundreds of e-mails I received from teachers, students and
those long out of school. All were enthusiastic and supportive of the notion of using
superhero comics to illustrate basic physics. I believe that there is a large untapped
interest in science in the general public, and as a professor I hope to continue to share
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with this audience the pleasure that comes from seeing that the world is a knowable
place.
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