Resonance

Resonance looks at the interactions between different objects. What happens when a vibrating object comes in contact with another object? Each object has natural frequencies of vibration or resonant frequencies. Using some data from my first lab as an example, we can see the natural frequencies of the harmonics of a single length of string with tension of 200 grams:

Frequency (hz)	Mode #
28.5	Fundamental (1st)
57	2nd
114	3rd
228	4th
456	5th

In order to get the string to reach stable harmonic structures, it had to be vibrated at these specific frequencies by the speaker that it was attached to. Resonance occurred at these five frequencies because the speaker was vibrating at the natural frequencies of the object. This gives us the definition of resonance: resonance occurs when a vibrating object comes into contact with another object and is vibrating at a resonant frequency of that object.

Resonance plays an integral role in the production of sound in instruments. Columns of air act as an object and have their own resonant frequencies, which I explored in my second experiment. This is fundamental in wind instruments. I like to use the clarinet as an example. To play a clarinet, one vibrates a reed on the mouthpiece, which creates resonance in the body of the instrument by vibrating the air particles in wave patterns that corresponding to the natural frequencies of the tube. In order to change the note being played, a clarinet player will place their fingers on different keys in order to block holes in the instrument. This changes the resonant frequency of the air column within the clarinet, which changes the frequency of sound produced by the instrument as the reed vibrates. The clarinet was designed so that the different fingering patterns create resonant frequencies that correspond to the frequencies of musical notes in the Pythagorean scale.

Works Cited:

1.  Gunther, Leon. The Physics of Music and Color. New York, New York: Springer, 2012.

2. "Resonance." Resonance. Physics Classroom. Web. 29 Sept. 2015.