Main Project Questions
(1) What new ideas did these articles teach me about this physics and society topic?
.....Through studying the causes and effects of the collapse of the Tacoma Narrows Bridge, we learned about a variety of terms and ideas. The term "resonance," for example: resonance occurs when a periodic force, such as an impulse, combines with the natural frequency, increasing the amplitude of a system. Obviously, resonance can cause a great effect-- as it did on the Tacoma Narrows Bridge, resulting in a complete catastrophe. 2
.....In our discovery of resonance we also found more physics we hadn’t previously known. We found that systems have natural frequencies. These frequencies are usually based on “the stiffness of the material, the mass of the material, and the size of the object."2
.....Based on the collapse, it was found that Tacoma Narrows Bridge was too narrow and the wind was too strong combined with the natural frequency. Winds often caused the bridge to oscillate in larger patterns. On this particular day though, they were so large in amplitude and coming in at the right angle that the bridge failed to stay in tact and collapsed.2, 1
.....We also learned that resonance is not always a bad thing. In the case of the Tacoma Narrows, it was not a favorable occurrence, but in other instances it can be. An example of resonance being helpful would be a child being pushed on a swing, when another pushes at the opportune time, they are combining the frequencies, resulting in the child soaring higher. We even found a group that is using the exact problem that Tacoma Narrows had in order to capture the energy to help propel a boat.4, 3
.....Another idea that we came across was that often resonance can be avoided if the appropriate precautions are taken. In the case of Tacoma Narrows, there were a few attempts made to reduce the bridge movements (such as tying down cables), but none of these seemed to be enough. From this disaster along with other experiments it is found that the installation of dampeners could reduce the risk of repeating the Tacoma Narrows incident. Dampeners are installed “in order to interrupt the resonant waves.” If interrupted, these waves are unable to grow, and are therefore unable to cause destruction.1
(2) How could this physical science be utilized by today's society? How could this affect society?
.....Since the collapse of the original Tacoma Narrows Bridge, a second Tacoma Narrows Bridge has been built in its place. Much preparation and study went into the second bridge, to ensure its stability as a suspension bridge. The first step was to understand why the original Tacoma Narrows collapsed in 1940. "One might speculate that fluctuations in the wind speed matched the natural frequency of the bridge causing it to resonate." 2 Frequency and resonance are parts of physical science, and thus began the physics of suspension bridges.
.....Years were spent studying aerodynamics and the affects it had on suspension bridges. "A special wind tunnel was constructed at the University of Washington for testing three-dimensional bridge models; the first time such models had ever been built." 5 New methods for building suspension bridges were developed over a four year period. The test results were then sent out to be studied by a national committee comprised of engineers across the country. This would ensure that any future suspension bridges would have the proper structure to withstand the physics of nature and thus avoid collapsing like the Tacoma Narrows Bridge.
.....The work that went into the building of the new Tacoma Narrows Bridge had an affect on suspension bridges nationwide. It was the first time a team of engineers had gotten together and done so much research on the design and structure of a suspension bridge. This set a precedent in the world of bridge building. Without the failure of the original Tacoma Narrows Bridge, the world would not be so fortunate as to have the convenience of such well-built suspension bridges.
1 “How Bridges Work: Additional Bridge Forces.” Howstuffworks. Ed. Michael Morrissey. 1998. 6 Mar. 2002. http://www.howstuffworks.com/bridge5.htm
2 Kirkpatrick, Larry D., and Gerald F. Wheeler. “Physics: A World View.”4th ed. Fort Worth: Harcourt College. 2001.
3 “Spaceships Made Of Concrete? Could Happen, UAH Says.” Daily University Science News. Ed. Phillip Gentry. 7 June 2001. 22 Feb.2002.
http://unisci.com/stories/20012/0607013.htm
4 “Vocabulary for Bridge Designers.” 12 Dec. 1999. 6 Mar. 2002.
http://www.uwlax.edu/globalengineer/draft/vocabulary/index.voc.html
5 www.nwrain.net/~newtsuit/recoveries/narrows.htm
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