In this project, we worked with frequencies and wavelengths to make musical instruments. Our project was to make three different types of instruments. We had to build a chime/drum instrument. We had to make a wind instrument and finally a string instrument. We then had to make the instruments play a scale, which is a note to another note usually one octave higher than the first one. Here is a description of our instruments and what they can play.
Chimes: Our chime instrument demonstrates that both the natural frequency of materials and the length of chimes affect the pitch created when chimes are struck (although length plays a lesser role). Our chimes used metal pipes cut to specific lengths to produce different notes. Every material has a different natural frequency, thus the notes are created because the certain lengths of pipe have different natural frequencies, individual to the material. However, since all of our chimes are made from the same material (and the same pipe), the length of the pipes played a major role in generating our notes. So, we calculated the needed lengths of the pipes with a chart linked on Mr. Williams’ website. Our starting length for our pipes was 30 cm, and then we used all the major notes.
[1]
Our chimes are tuned to a D Major scale (D, E, F#, G, A, B, C#, D).
Wind instrument: Our wind instrument proves that air pressure and the length of the tube determines the resulting note when the instrument is played. Our wind instrument is a 35 cm long piece of PVC pipe as the neck of our instrument. At the end of the instrument is a funnel that serves as the bell. The bell resonates and amplifies the sound produced by the instrument. Our instrument is a brass instrument and, thus, uses vibrations of the lips to cause vibrations in the tube. The tube also plays a significant role in determining pitch, because air pressure is greatest at the mouthpiece and lowest at the opening. The pressure differences result in the instrument creating a quarter of a wave, as the mouthpiece is at high pressure, which produces the crest of sound waves, and the bell is at pressure equal to the atmosphere, which produces a point of the wave at equilibrium. This means that, in order to generate a desired pitch, we must either reduce or increase the distance between the areas of high and low pressure, the length between equal to a quarter of the wavelength of the note. The instrument is currently capable of playing notes ranging from c4 to c5. Here are the notes and where we placed them from the start of our instrument.
Notes
C5
B4
A4
G4
F4
E4
D4
C4
wavelength
523.25
493.88
440.00
392.00
349.23
329.63
293.66
261.63
cm from mouth
16.48 cm
17.46 cm
19.6 cm
22 cm
24.6 cm
26.16 cm
29.37 cm
32.96 cm
frequency
65.93
69.85
78.41
88.01
98.79
104.66
117.48
131.87
String Instrument: Our string instrument demonstrates that the length of a vibrating material has an effect on the pitch created by said material. Our string instrument consists of a 1.3 meter long wood plank with strings and a metal sound box, modeled somewhat like a guitar. The sound is generated via the vibrations of the strings, when the strings are plucked. The notes are then amplified via a metal sheet that the vibrates with the sound waves created by the strings. The note played, as stated above, is determined by the length of the string when it is plucked. This raises a simple question: why? The reason: when a string is plucked, it generates a single standing wave, which is half of a wavelength. Thus, because each note corresponds to a different wavelength, changing the length of the string will determine which note we will play. To elaborate, when we play a note, because the strings generate half of a wavelength, we press down on the string at a distance equal to half of the length of the wavelength that corresponds to each note. For example, when we play C4, which is more commonly known as Middle C and has a wavelength of about 132 cm, we press down about 66 cm away from the bridge.
Note:
Wavelength:
Length From Bridge:
G3
176.02 cm
88.01 cm
A3
156.82 cm
78.41 cm
B3
139.71 cm
69.855 cm
C4
131.87 cm
60.935 cm
D4
117.48 cm
58.74 cm
E4
104.66 cm
52.33 cm
F#4
93.24 cm
46.62 cm
G4
88.01 cm
44.005 cm
Here are some terms that we learned in this Unit.
Wavelength-length of a wave from crest to crest
frequency-how many waves are created or pass in a certain unit of time
Period-amount of time between waves/vibrations
wave speed-velocity of a wave
amplitude-displacement from equilibrium to crest
transverse wave-goes up and down as it rises along
longitudinal wave-a wave that compresses and expands back and forth as it travels along.
Chimes: Our chime instrument demonstrates that both the natural frequency of materials and the length of chimes affect the pitch created when chimes are struck (although length plays a lesser role). Our chimes used metal pipes cut to specific lengths to produce different notes. Every material has a different natural frequency, thus the notes are created because the certain lengths of pipe have different natural frequencies, individual to the material. However, since all of our chimes are made from the same material (and the same pipe), the length of the pipes played a major role in generating our notes. So, we calculated the needed lengths of the pipes with a chart linked on Mr. Williams’ website. Our starting length for our pipes was 30 cm, and then we used all the major notes.
[1]
Our chimes are tuned to a D Major scale (D, E, F#, G, A, B, C#, D).
Wind instrument: Our wind instrument proves that air pressure and the length of the tube determines the resulting note when the instrument is played. Our wind instrument is a 35 cm long piece of PVC pipe as the neck of our instrument. At the end of the instrument is a funnel that serves as the bell. The bell resonates and amplifies the sound produced by the instrument. Our instrument is a brass instrument and, thus, uses vibrations of the lips to cause vibrations in the tube. The tube also plays a significant role in determining pitch, because air pressure is greatest at the mouthpiece and lowest at the opening. The pressure differences result in the instrument creating a quarter of a wave, as the mouthpiece is at high pressure, which produces the crest of sound waves, and the bell is at pressure equal to the atmosphere, which produces a point of the wave at equilibrium. This means that, in order to generate a desired pitch, we must either reduce or increase the distance between the areas of high and low pressure, the length between equal to a quarter of the wavelength of the note. The instrument is currently capable of playing notes ranging from c4 to c5. Here are the notes and where we placed them from the start of our instrument.
Notes
C5
B4
A4
G4
F4
E4
D4
C4
wavelength
523.25
493.88
440.00
392.00
349.23
329.63
293.66
261.63
cm from mouth
16.48 cm
17.46 cm
19.6 cm
22 cm
24.6 cm
26.16 cm
29.37 cm
32.96 cm
frequency
65.93
69.85
78.41
88.01
98.79
104.66
117.48
131.87
String Instrument: Our string instrument demonstrates that the length of a vibrating material has an effect on the pitch created by said material. Our string instrument consists of a 1.3 meter long wood plank with strings and a metal sound box, modeled somewhat like a guitar. The sound is generated via the vibrations of the strings, when the strings are plucked. The notes are then amplified via a metal sheet that the vibrates with the sound waves created by the strings. The note played, as stated above, is determined by the length of the string when it is plucked. This raises a simple question: why? The reason: when a string is plucked, it generates a single standing wave, which is half of a wavelength. Thus, because each note corresponds to a different wavelength, changing the length of the string will determine which note we will play. To elaborate, when we play a note, because the strings generate half of a wavelength, we press down on the string at a distance equal to half of the length of the wavelength that corresponds to each note. For example, when we play C4, which is more commonly known as Middle C and has a wavelength of about 132 cm, we press down about 66 cm away from the bridge.
Note:
Wavelength:
Length From Bridge:
G3
176.02 cm
88.01 cm
A3
156.82 cm
78.41 cm
B3
139.71 cm
69.855 cm
C4
131.87 cm
60.935 cm
D4
117.48 cm
58.74 cm
E4
104.66 cm
52.33 cm
F#4
93.24 cm
46.62 cm
G4
88.01 cm
44.005 cm
Here are some terms that we learned in this Unit.
Wavelength-length of a wave from crest to crest
frequency-how many waves are created or pass in a certain unit of time
Period-amount of time between waves/vibrations
wave speed-velocity of a wave
amplitude-displacement from equilibrium to crest
transverse wave-goes up and down as it rises along
longitudinal wave-a wave that compresses and expands back and forth as it travels along.
Reflection. This project over all was a good one. It was very fun to make and design all the instruments and play them. As a group, we worked very poorly. Nobody had a set plan of what we were going to do that day. I have to work on leadership and my empathy. I sometimes got frustrated when people weren't doing anything. I did do good with work ethic and productivity. I built two of the instruments with a partner and they turned out pretty well.