When the original Tacoma Narrows bridge was built in 1940, its design inadvertently caused it to resonate with the wind gusts through the Narrows. The bridge had a tendency to sway in the wind, which earned it the nickname "Galloping Gertie." The ultimate fate of this constant swaying is dramatically illustrated in the following newsreel.
The bridge even made an appearance in an advertisement for Pioneer speakers in the '90s.
Wednesday, April 09, 2008
Wednesday, April 02, 2008
The Doppler Effect
The Doppler Effect results when a wave source and an observer are in relative motion. The most notable example is with sound, but it occurs with all waves. Click on each link below to see examples and explanations of the Doppler Effect.
Wave Applet
This is a really neat applet from the University of Colorado that allows you to control a variety of parameters for waves on a string. Check it out!
Wave Applet
Wave Applet
Tuesday, April 01, 2008
Wave Forms
[The following animations were created using a modifed version of the Mathematica® Notebook " Sound Waves" by Mats Bengtsson, and come from http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html]
Longitudinal Waves
In a longitudinal wave the particle displacement is parallel to the direction of wave propagation. The animation below shows a one-dimensional longitudinal plane wave propagating down a tube. The particles do not move down the tube with the wave; they simply oscillate back and forth about their individual equilibrium positions. Pick a single particle and watch its motion. The wave is seen as the motion of the compressed region (ie, it is a pressure wave), which moves from left to right.
Transverse Waves
In a transverse wave the particle displacement is perpendicular to the direction of wave propagation. The animation below shows a one-dimensional transverse plane wave propagating from left to right. The particles do not move along with the wave; they simply oscillate up and down about their individual equilibrium positions as the wave passes by. Pick a single particle and watch its motion.
Longitudinal Waves
In a longitudinal wave the particle displacement is parallel to the direction of wave propagation. The animation below shows a one-dimensional longitudinal plane wave propagating down a tube. The particles do not move down the tube with the wave; they simply oscillate back and forth about their individual equilibrium positions. Pick a single particle and watch its motion. The wave is seen as the motion of the compressed region (ie, it is a pressure wave), which moves from left to right.
Transverse Waves
In a transverse wave the particle displacement is perpendicular to the direction of wave propagation. The animation below shows a one-dimensional transverse plane wave propagating from left to right. The particles do not move along with the wave; they simply oscillate up and down about their individual equilibrium positions as the wave passes by. Pick a single particle and watch its motion.
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