Tacoma Narrows Bridge (1940) Billah and Scanlan (1991) reported that in fact, many physics textbooks (for example Resnick et al. and Tipler et al.) wrongly explain that the cause of the failure of the Tacoma Narrows bridge was externally forced mechanical resonance. Resonance is the tendency of a system to oscillate at larger amplitudes at certain frequencies, known as the system's natural frequencies. At these frequencies, even relatively small periodic driving forces can produce large amplitude vibrations, because the system stores energy. For example, a child using a swing realizes that if the pushes are properly timed, the swing can move with a very
Interface metaphor to making it resemble something the users understand. Experts, on the other hand, understand what is going on with the technical aspects of an interface metaphor. They know what they want to do and they know how to do it—and so they design shortcuts to facilitate achieving their goals. While the concept behind interface metaphors appears simple (to promote more efficient facilitation of a computer), a lack of empirical evidence exists to support these claims. Little research has actually been completed that demonstrates the benefits of implementing metaphors in computer systems as well as what makes a metaphor most effective.