Resonance

Resonance

Resonance is the in-phase addition of waves, or in other words, producing vibrations near or on a natural frequency. However, this only occurs at the system's "Resonant Frequency(also the natural frequency)." Resonance is cased by the production of Sound Waves so that two antinodes "resonate". There are four types of resonant systems; Mechanic, Acoustic, Electromagnetic, and Quantum wave functions.

Examples:


 * A illustration of an example of Resonance wold be the periodic application of a force towards a oscillating object, such as a pendulum. If you apply an oscillating force when the pendulum is at it's maximum acceleration, and its maximum amplitude, and this force is oscillating at the same frequency constantly, the pendulum will begin to gain amplitude as the force is continually applied. So in other words, if you keep the pendulum resonating at its natural frequency, it will begin to increase its swing.


 * Another example of resonance is in a open-ended tube. When there is a frequency sound applied to on end of the tube, at the tube's natural frequency, then there will be an antinode at both ends, and the sound will RESONATE, and sound louder.[[image:Photo_2.jpg width="656" height="184" caption="Fig 1: Using resonance to find speed of sound in air."]]
 * For a closed-ended tube, the equation looks like the following. The Frequency equals the harmonic(n), times the velocity of the wave(v), divided by four times the tube's length(L).

media type="file" key="Resonance.mov" This is an example of sets of sticks with the same natural frequencies. When one of the tall sticks is moved, the other tall one moves too due to the resonance in the base at the natural frequency. The same phenomenon occurs for the other two sticks. NOTE: The sticks do not actually make these noises.

Tacoma Narrows Bridge Another example of resonance is the wind forces on the Tacoma Narrows Bridge. The wind was blowing at the bridges natural frequency causing the bridge to twist and sway, even though it was made out of strong materials. For more information on the Tacoma Narrows Bridge and also the source to buy the full, color video, go [|here]. media type="file" key="TCBridge.mov"