Build a Band

A picture of my guitar in progress before quarantine^^^^^

Description of My Guitar

cuitars are a type of string instrument. String instruments produce sound waves by vibration of the string. There are many different ways to create different notes including frets and different strings. The string length, string tension, and string thickness are all factors of the pitch and sound of the note being produced by the guitar. At first I was going to try to use rubber bands as strings. But then I realized I had previously attempted this back in 8th grade (it did not go well). So I went down the route of real guitar strings. I thought that it would give it a little touch of reality and it could also sound a lot better. The string length of the string relates to the note because half of the wavelength of the note you are trying to produce. The string tension relates to pitch because if you tighten a string it causes the frequency to go up which causes the pitch to become higher. I also made a sound box to give the notes a nice tone and amplify the sound. I made it out of wood because metal resonates easier than it and wood causes the echo of the sound to ricochet. All of the elements of a guitar for example the string, box, and the air in the sound box vibrate and force nearby air particles into vibrational motion. Therefore a guitar creates sound using forced vibration. Specific details are described below:

Strings:

- wavelength of strings (the length of the wave that the string makes when you pluck it)

E1 837.31

A2 313.64

D3 234.96

G4 88.01

- String Length (1/2 wavelength based on crest/trough of standing wave)

E1 418.655

A2 156.82

D3 117.48

G4 44.005

- frequency ( number of waves per second)

E1 41.20

A2 110.00

D3 146.83

G4 392.00

- string tension

Extra Light Strings 131 pounds

- string thickness

E -0.010 inches

A - 0.014 inches

D - 0.023 inches

G - 0.030 inches

B - 0.039 inches

E - 0.047 inches

- resonance or forced vibration

Forced vibration because you are physically vibrating the string with your finger or pick.

Song

“Waves”

The back and forth vibration of a pendulum

You cannot hear it, it's a conundrum

Oscillatory simple harmonic motion

They are a type of wave just like in the ocean

Most information around us comes from a wave

When the information dies it goes straight into the grave

The speed of the wave depends on the medium

Its faster in water than it is in helium

Sound waves 350 meters flying by

Can miss it in the blink of an eye

Sound, light, water all types of waves

Sound waves are amplified in caves

Light waves give your eyes a fright

Because they are so very bright

Ocean waves seem to have it right

A material such as rock will not share its space with another

It's almost like they are big and little brothers

Waves could be increased, decreased, or neutralized

But it makes sense because they have to be revised

Constructive interference when they are increased

That is why waves can be such beasts

Wave interference is easiest to see in water

Swimming through the water like they are otters

Whether the waves are water, sound, or light

Don't worry they do not bite

Sound, light, water all types of waves

Sound waves are amplified in caves

Light waves give your eyes a fright

Because they are so very bright

Ocean waves seem to have it right

If you tie a rope to a wall and shake it up and down

Waves are produced then they dim down and drown

When a light source arrives frequencies sky high

They are almost as tall as the blue sky

When two waves of similar frequencies interfere you get a beat

And you know this beat is gonna be straight heat

A beat frequency is a pulsing sound

A beat frequency helps me make this rap all around

Sound, light, water all types of waves

Sound waves are amplified in caves

Light waves give your eyes a fright

Because they are so very bright

Ocean waves seem to have it right

Beat Link: https://youtu.be/VEi6uSrYEy4

Beat description: Very repetitious like a wave! Uses the same notes and same drum beat.

Design Build Cycle

I designed my guitar by looking at pictures of guitars and them as a model. My experience playing guitar also helped me a lot in making a design. In the middle of the project, we got interrupted by Corona Virus / Covid-19. At that point I had built the body and neck of the guitar. I chose to build the sound box out of wood, because wood causes the echo of the sound to ricochet. Solid construction of the sound box gives the notes a nice tone and amplifies the sound. I was starting to test out materials for strings when we got put in shelter in place. I could not really test my guitar because of the Corona Virus. However, in 8th Grade I tried to make a guitar and I didn't pick a good string material. Having learned from that, this time I was planning to make the guitar with real guitar strings.

Content

Energy is transferred in the form of waves and there are models to predict how the energy is transferred.

Velocity=Frequency x Wavelength or v=f𝝺

Frequency: Frequency is the number of occurrences of a repeating event per unit of time

Wavelength: The distance between successive crests of a wave, especially points in a sound wave or electromagnetic wave.

Wave Speed: Wave speed is the distance a wave travels in a given amount of time

Amplitude: The maximum extent of a vibration or oscillation, measured from the position of equilibrium. The maximum difference of an alternating electrical current or potential from the average value.

Transverse wave: A wave vibrating at right angles to the direction of its propagation.

Longitudinal wave: A wave vibrating in the direction of propagation.

Electromagnetic Spectrum: The range of wavelengths or frequencies over which electromagnetic radiation extends.

Guitars produce sound by vibration of the string. A guitar string has a number of frequencies at which it will naturally vibrate. The frequency at which the string vibrates depends on the tension of the string, the linear density of the string, and the length of the string.

The equation, speed = frequency x wavelength can be used to calculate the length of string required to produce a frequency.

The length of a guitar string effects the note because the wavelength of the string is the length x 2.

The velocity in a guitar string depends on the square root of the tension divided by the linear density. Thicker guitar strings have a higher linear density. So thicker (denser) strings have a larger denominator (since they have more mass per unit length) and produce a lower velocity wave. Since frequency is proportional to the velocity in the equation v=f𝝺 , thicker strings produce lower frequencies.

The string tension relates to the pitch because if you tighten a string it causes the frequency to go up which causes the pitch to become higher. (Velocity = square root of the tension divided by the linear density. If the tension is increased, then velocity of the wave is increased and frequency is proportional to velocity.

Reflection

This project was interrupted pretty early by the COVID-19 pandemic. I was disappointed to not be able to complete building the guitar because I play guitar and am very interested in both music and physics. I think that the transition to online learning went pretty well though. I have realized that I actually am a bit better at getting all of my work done when everything is listed all in the same place online. It sort of forces organization. I think this helped me be a conscientious learner.

Even though I play three instruments, I had never tried writing a song before. I actually really enjoyed writing the song lyrics for this project and I think it turned out pretty well. (My first draft was not so good, but it got better after a couple revisions, and some collaboration with friends online who suggested some rhymes. Even though I got some input from friends on the song, it was different not being able to collaborate with my classmates on the project because of the shelter in place. I had to use critical thinking to find ways to learn the material using different online materials. I think I would have had an easier time learning the physics concepts if we had been able to continue the hands on work. But overall, the project was successful in a difficult situation.