Whole Foods' Guitar

For our second unit of Light and Sound, we learned about Sound and how it works. We were assigned to build a guitar out of recycled materials. The purpose of this action project was to use the knowledge we acquired and to create a functional guitar. I learned how the decibel scale (a logarithmic unit of measurement measuring the amplitude of a sound wave) works. I am proud of the research I did during external investigation.

GN, Drawing 2015

The main source of sound in a guitar is the string. When plucked, the strings vibrate. The vibrations travel through the saddle to the bridge to the soundboard, vibrating the soundboard. The form of the guitar is a hollow sound box which amplifies the vibrations. The frequencies produced can depend on the string length, tension, and diameter.

To make this guitar, I used a Whole Foods plastic bowl, two pieces of wood, hard cardboard, thumb tacks, and lots of glue! I put two thumb tacks through the hard cardboard, so that the rubber bands could be attached. I placed the two wood pieces and the hard cardboard across the bowl and glued it together as the neck of the guitar.

GN, Design 2015

GN, Guitar 2015

Since I used a rubber band, there are two strings you can pluck. Each one is 17.5 inches long. One open note is a F#4, with a frequency of 370 Hz and wavelength of 93.24 cm. The octave note is a Gb5 with a frequency of 740 Hz (370X2) and wavelength of 46.62 cm (93.24/2). The octave is the half way point of my string.

The thickness of the rubber band is about 0.59 mm. I used a bowl which had a radius of 3.5 inches. The formula for the volume of a cylinder is 4/3piR^3. This formula gives the volume of a complete sphere. In order to find the volume of the bowl I had to divide the volume of the sphere by two. The volume of the sphere was 179.59438 cubic inches (4/3 X pi X 3.5^3). The volume of the bowl was 89.79719 cubic inches (179.59438/2).

You can hear my guitar below.



The Doppler Effect is a phenomenon in which there is a change in frequency of a wave for an observer moving relative to its source, because as the source moves forward the sound waves are being pushed together resulting in a higher pitch.

My guitar could illustrate this concept if a guitarist were to walk and play; as he walks forward the sound wave will be pushed together resulting in a higher pitch sound to the observer/listeners, whereas if he/she were walking away the sound waves would be more spread apart and they would sound lower.

Vocabulary terms:
- Sound waves: Sound waves are longitudinal pressure waves by which sound is propagated (Online Dictionary).
- Frequency/pitch: The frequency is the number of cycles per second past a given point. Hertz is the unit measurement used for frequency.
- Amplitude: The amplitude is the displacement of a wave from its mean value (What Is Amplitude?). It is experienced as "loudness" or volume.
- Wavelength: The wavelength is the length of one complete wave cycle.

Work Cited:

• Online Dictionary
• Amplitude. (2015, February 9). In Wikipedia, The Free Encyclopedia. Retrieved 21:34, March 5, 2015.
• "What Is Amplitude? Amplitude Particle Displacement How to Calculate Amplitude Sound Wave Peak Amplitude Wave Sound Signal Sound Pressure Gradient Calculate Amplitude vs Voltage Definition Sound Particle Velocity Terms Question Calculate Amplitude Maximum Displacement Equilibrium Exact Definition Decibel Scale Sound Wave Pressure Gradient RMS Sound Field Quantity Elongation Oscillation of a String Peak to Peak Elongation Longitudinal Pressure Waves Wavelength Period Frequency - Sengpielaudio Sengpiel Berlin." What Is Amplitude? Amplitude Particle Displacement How to Calculate Amplitude Sound Wave Peak Amplitude Wave Sound Signal Sound Pressure Gradient Calculate Amplitude vs Voltage Definition Sound Particle Velocity Terms Question Calculate Amplitude Maximum Displacement Equilibrium Exact Definition Decibel Scale Sound Wave Pressure Gradient RMS Sound Field Quantity Elongation Oscillation of a String Peak to Peak Elongation Longitudinal Pressure Waves Wavelength Period Frequency - Sengpielaudio Sengpiel Berlin. N.p., n.d. Web. 05 Mar. 2015.