Diddley Bow

MS(2016) Diddley Bow

This is the unit 2 action project for Light, Sound, and Time. Unit 2 of the course focused on sound. We investigated the human ear and learned about different organisms' ability to hear and produce sound. The course taught us the concept of sound as a wave and learned about the speed of sound and how different mediums affect it. We learned about a variety of instruments and their various ways of creating sound. For the unit’s action project we were asked to design and build our own diddley bows or one string guitars. This unit refined and reinforced my previous understanding of sound. The in-depth research and experimentation we did allowed me to look at sound in the context of math and science which in turn allowed me to develop a stronger overall understanding. I’m really proud of my ability to better grasp the concept of sound. I’m proud that this unit has left me with a strong understanding of something so universal and integral to life.

MS(2016)Diagram

The diddley bow I created produces sound when the string is plucked or strung. The vibration of the string becomes amplified and echoes through the cylindrical can located at the end of the device. The tension of the string allows for a certain pitch to be achieved while the volume is dependent on the strength of one's pluck. The diddley bow I created demonstrates a variety of the key science principles we studied and examined in the unit’s internal investigation. It demonstrates sound waves in several ways. When the string is plucked a sound wave is formed and travels through the tin can amplifier. The pitch/frequency of the diddley bow was determined by the tension of the string. How hard you pluck the string will determine the sound wave’s amplitude otherwise known as its volume. The Doppler effect is the apparent change in frequency of a sound wave due to motion relative to the listener. My diddley bow doesn’t directly demonstrate the Doppler effect but there could be a situation in which it would in fact demonstrate the Doppler effect. For instance, if I were strolling along the sidewalk playing a melody on the diddley bow, the person I would be approaching would be perceiving the sound waves as higher frequency while the person I had just walked past would experience the frequency decreasing. The data and measurements associated with my device are as follows: Length of vibrating string - 17 1/4th IN, ½ - 8.625 IN, ⅓ - 5.75 IN, ⅔ - 11.5 IN, ¼ - 4.3125 IN, ¾ - 4.9375 IN. The thickness of the string is .044 IN and the volume of the cylindrical tin can is 31 IN. The formula used for the volume of a cylinder was πRxR x H. The open pitch of the diddley bow is A# and has a frequency of 233.08 Hz and a wavelength of 148.02 cm. The first four harmonics along with their frequencies and wavelength are as follows: 1:466.16 Hz 74.01 cm, 2:699.24 Hz 49.34 cm, 3:932.32 Hz 37.005 cm, 4:1165.40 Hz 29.604 cm.

MS(2016)Harmonics

The recording I created uses a slide in it to alter the strings pitch. A metal slide was placed over my finger and while plucking with my other hand the slide was moved across the string to produce carrying pitches. It changes the pitch because it is altering the length of the string, a factor that alters pitch. I’m very pleased with the outcome of my project. I feel as if I designed and created a functioning diddley bow the demonstrates a variety of the key science and math principles from the unit’s internal investigation. If I were to do the project a second time I would take the knowledge I gained from the unit and the building experience to alter the design in a way which would produce an overall better functioning device. I would have loved to make my diddley bow come alive with color and additional design. Overall I am very pleased with the outcome of this unit and project as it provided me with a strong understanding of sound as well as allowed me to create a functioning musical instrument.