Introduction
In this unit, we were instructed to study, understand, and then build musical instruments that worked properly and made correct notes. We started by studying and beginning to understand how sound traveled, and why we can hear different notes and pitches. Once we got a clearer understanding of how sound waves work, we began to design instruments that, based on what we learned, we predicted to play correct notes when used. We made these predictions based on known wavelengths of notes, and designed our instruments to match these wavelengths.
What is Sound and how does it work?
Sound are essentially differences in pressure in a medium such as air. They are created by the vibration of an object, which causes the air surrounding it to vibrate. The vibrating air then causes our eardrums to vibrate, which the brain interprets as sound. Sound waves can be shown in a normal x versus y graph like the one pasted below.
The picture pasted below might help give you a better understanding of what the graph above represents. It can sometimes be hard to comprehend what a two-dimensional graph represents in our three-dimensional world.
Key terms and vocab
Sound waves - created by the vibrations of material objects; compression and rarefaction
Compression - the pushing together of particles in a fluid (usually air)
Rarefaction - pulling apart
Medium - a material or liquid for sound to travel through (air, water)
Amplitude - distance from the midpoint to the crest (top of the wave) or trough (bottom of the wave)
Wavelength - distance from crest to crest
Frequency - how often a vibration occurs in Hertz, or cycles per second
Period - amount of time between waves
Wave - a compression or refraction of molecules traveling through a substance
Transverse waves - move up and down
Compressional Waves- moves compression horizontally
Longitudinal waves - moves compression horizontally
Positive (Constructive) interference - waves combine to make one larger wave
Non Constructive interference - waves cancel each others power out
Node - area between a wave
Anti node - the maximums and minimums of a wave
Pitch - due to varying frequency, creates different notes that we hear
Resonance- when unnatural waves are equal to the the natural frequency of an object
Compression - the pushing together of particles in a fluid (usually air)
Rarefaction - pulling apart
Medium - a material or liquid for sound to travel through (air, water)
Amplitude - distance from the midpoint to the crest (top of the wave) or trough (bottom of the wave)
Wavelength - distance from crest to crest
Frequency - how often a vibration occurs in Hertz, or cycles per second
Period - amount of time between waves
Wave - a compression or refraction of molecules traveling through a substance
Transverse waves - move up and down
Compressional Waves- moves compression horizontally
Longitudinal waves - moves compression horizontally
Positive (Constructive) interference - waves combine to make one larger wave
Non Constructive interference - waves cancel each others power out
Node - area between a wave
Anti node - the maximums and minimums of a wave
Pitch - due to varying frequency, creates different notes that we hear
Resonance- when unnatural waves are equal to the the natural frequency of an object
Our instruments and thier explanations
Our flute works by splitting the air blown into the hole at the end with a thin piece of pvc pipe. The split air creates a sound that travels through the pipe with a wavelength of 4x the distance the the nearest break in the tube. We drilled the six holes where they are by dividing the distance of the six notes we wanted to be able to play by four.
Although our guitar didn't end up being able to play the correct notes, it did end up being able to play notes and it did work. We started by building a frame, and then proceeded to add strings to the frame. We had a lot of trouble with the tension of the strings on the frame of the guitar and the wood started to warp soon. The strings also loosened overtime which made it impossible to add correct frets for the notes we wanted. We ended up having to settle for an adjustable fret and we ended up playing it by ear.
I didn't work much on the jars so i don't know too much about how we built them, but i do know that finding the correct note essentially took filling them up, and testing them with a tuner until we got it right. They work because with hitting the jars with a spoon, we create a vibration throughout the water and the jar that sends sound waves to our ears. The more water, the smaller the room for vibration is and the higher pitched it is, and vice-versa.
Reflections
I learned a ton of things in this project about sound waves and how they work. This project taught me a lot about working with groups, and also helped me understand music better. Building the instruments gave me a better understanding of how real instruments work, and how musicians use them. I also learned valuable lessons about how to move on and fix things when i mess up, we had a lot of mistakes to fix. I didn't like parts of this project because of a lack of clear instruction and structure in class. Overall this project taught me a lot and I am very glad we did it.