Building a Guitar

In the second unit of my STEAM course Light, Sound, and Time, we learned all about sound. By looking sound both in a science perspective and a mathematical perspective, we were able to learn how sound travels and how we can use math to calculate different features of the wave. For our Action Project, we were asked to make a makeshift guitar. By doing this, we could demonstrate both our knowledge of the math behind waves and how sound travels through a guitar.

Diddley Bow (2017) LS

In our internal investigation, we looked at how sound travels. What we discovered was that sound travels at a speed of ~343 meters per second. We also learned how the amplitude of a sound wave affects the volume and how the frequency and wavelength affect the pitch. In my makeshift guitar, the sound gets created by strumming the sting. Then, the vibrations travel down the length of the string and into the tin can. There, the sound gets amplified and the sound waves go out the open end of the can.

Harmonics (2017) LS

To make my guitar, I used a tin can, a piece of wood, screws, a battery, and a guitar string. The string I used was 0.02 in thick. I first put a hold in my can with a sharp object. Then, I secured the tin can with one screw on each side. To put the string on, I winded the string on one each on each side of the guitar, making sure to pull it tight and run it through the hole in the tin can. You can hear me playing my diddley bow here.

Diagram (2017) LS

The calculations I did on my guitar were based off of the trapezoid shape that the string makes with the top of the wood. I turned the top half of the trapezoid into a triangle to use trigonometry to find the measurements of some of the angles. The length of the string from he can to the battery was 13.5 in, the length of the wood from the can to the battery was 13 in, the height from the top of the wood to the string by the tin can was 0.5 in, and the height from the top of the wood to the string by the battery was 0.25 in. I used the inverse tangent of angle y to find it's measurement then used that information and my knowledge of triangles to find the rest of the angles. I also found the volume of the tin can by using the formula v=pi*r^2*h and I got 35.5 in^3. Finally, I found the thickness of my string to be 0.02 in.

Calculations (2017) LS