Running head: MYTH BUSTED
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Myth Busted
Amanda Drews
Ivy Tech Community College
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Watching episodes of Myth Busters is an interesting way to see inquiry at work on a very
large scale. The episode that caught my attention originally aired on October 21, 2012 (Season
11, Episode 3). The title of the episode is “Hail Hijinx”. I did not choose the part of the episode
about hail, but rather, I chose the part about leaping from an exploding bridge.
The topic is selected because of a scene at the end of the movie, “Cliffhanger,” where
Sylvester Stallone successfully jumps to safety at the end of the bridge as it explodes, causing
one end to fall. The investigative team decides to test and see if this is actually possible. The
guiding question for this experiment is “Can you leap up on a bridge that is going down?” Their
claim is that the possibility of leaping up from a falling bridge is doubtful. It doesn’t seem
plausible. Jamie and Adam start off by planning a bench test, performing small scale tests of the
situation. They start by building a miniature suspension bridge, a miniature Adam built off of a
pneumatic cylinder, and an electrically activated solenoid that will stand in for an explosion. All
of these things are controlled by the investigators, including the timing down to one millisecond.
The control for the experiment is launching the jumper while the bridge is stable.
They start out by delaying the jump by 50 milliseconds, then by 100, and 150. Each
time, the jump becomes less, until there is no time to jump at all. A modification is made in this
experiment so that the jumper is jumping at an angle, instead of straight up like they began
doing. After their experiment on a miniature scale, they conclude that there is a VERY small
amount of time for a person to leap after the explosion. Their claim after the small scale
experiment is that the myth does not seem plausible. On the actual experiment with a real person
on a real bridge, human reaction time, increase in mass and distance, and wind resistance will all
affect the outcome.
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Next, Jamie and Adam plan a full scale experiment to test the myth. They build a
suspension cable bridge, like the one used in the movie. The bridge is made of wood planks and
steel wire. It is 80 feet long and weighs 1,600 pounds. It is as close as they could get to the
bridge used in the movie. When putting the bridge in place, they make sure it has just the right
amount of droop. One end of the bridge is mounted down, while the other will have quick
releases hooked to them that will be released electronically to explode and cause it to fall. These
things are done so that the experiment could be repeated by other people.
At first, they try to do the same method of leaping as in the movie. This is a step-stepleap rhythm after the boom of the explosion is heard. After a couple trials of this, it proves that it
is not possible to reach the end of the bridge before it falls. They modify the method by
eliminating the two step start. The question that they are trying to answer still is if there is a tiny
period of time after the explosion for a person to react and leap. The final conclusion is that it is
totally impossible to react and leap to safety once the explosion happens. Immediately, the
bridge falls, leaving them with nothing to jump off. All the tests that are performed lead to the
conclusion that the myth is busted!
I think that the Myth Busters use scientific inquiry. They come up with questions that
they want to answer, and then design experiments that will help them to arrive at the answers to
their questions. This requires them to think critically and make observations that they can use to
support their conclusions. Even though they plan out their investigations, they modify these
plans based on their observations or questions that come up during the investigation. The
investigation team conducts experiments to learn if the myths hold true or not. They do not rely
on the research and knowledge of others, but instead gain the knowledge firsthand through these
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investigations. In this way, they learn the science concepts that are related to the questions they
are seeking to answer.
This investigation has many science concepts involved, especially physics related
concepts. Forces, such as gravity and tension, act upon the bridge both before and when it falls.
Gravity also acts upon the people, causing them to fall when the bridge falls beneath them. Air
resistance, or drag, would affect the person’s attempted forward leap to the end of the bridge. Of
course, the force of gravity makes sense to me because I experience it at all times, just like
everyone and everything else. However, I don’t know exactly how tension works in this
situation, but I do know that all of these types of forces play a huge role in the outcome.
One question that I had while watching the program had to do with the rate of falling of
the bridge and person. If the person did not have a safety cable attached to them, would they fall
to the ground at the same rate as the bridge fell? Of course, they would be dead when they hit
the ground, but I still wondered about this. After a little bit of research on the Internet, I found
that this question can be answered by understanding Newton’s second law of motion. According
to the Physics Classroom website, when the mass of an object increases, the acceleration
decreases (Henderson, 2013). The acceleration of an object is indirectly proportional to the mass
of the object. Going from that statement, it seems to me that the person would hit the ground
before the bridge because the bridge has more mass, meaning it would have less acceleration.
The other question that developed while watching was about the person not being able to
push off the bridge after it began falling. Why could he not push off after one end started
falling? I learned that this question ties into my uncertainty of how tension works upon the
bridge. The reason that the person could not push off of the bridge once it started falling was
because it lost its tension. In the after show to the episode that I watched, Jamie and Adam
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explained this in a way that made it make more sense to me. The tension that holds the bridge up
is like a rubber band that is stretched. Once the stretching, or tension, is released, it is like the
snapping of a rubber band that has been stretched and released. Basically, once the tension is
released, the guys have nothing that allows them to push off. Immediately, the forces act upon
them to pull them to the ground.
My research on tension led me to the website, “How Stuff Works”. Tension is the
pulling force acting on a bridge, and compression is the force pushing together. Their
explanation of tension on bridges made sense too. Just like in a game of tug-of-war, a
suspension cable bridge, like the one in this episode, is pulled in opposite directions on each end
(Lamb & Morrissey, 2000). When the pulling on one side stops, it causes the tension that holds
it tight to disappear. This makes it impossible to jump on and have any force with your jump.
These explanations help these concepts make more sense to me because they describe them using
things that I am more familiar with than I am bridges.
This was an interesting assignment to bring to light how scientific inquiry is used outside
of the classroom. Just like we are learning to do in our future classrooms, the Myth Busters ask
questions, make claims, and gather evidence through their investigations to support those claims.
Sometimes, the myths hold true, and sometimes, the myths are busted, but no matter what they
must have support and evidence that makes their claims hold strong.
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References
Hail hijinx [Television episode]. (2012, October 21). In Beyond Entertainment
(Producer), MythBusters. San Francisco, CA: Discovery.
Henderson, T. (2013). Newton's Second Law of Motion (ComPADRE, Ed.). Retrieved
September 15, 2013, from http://www.physicsclassroom.com/class/newtlaws/
Lamb, R., & Morrissey, M. (2000, April 1). How bridges work. Retrieved September
15, 2013, from http://science.howstuffworks.com/engineering/civil/
bridge2.htm u2l3a.cfm