A musical instrument creates frequencies of sound that match a musical scale. The beauty and richness of the sound come from the harmonics that are produced along with the fundamental frequencies.
Design challenge
Create a musical instrument that
plays the frequencies (within 5%) of all eight notes of a major scale,
has working parts consisting of a metal bar (or tube) with lengths less than 1 m, and
has a total mass of less than 5 kg.
Based on the above instructions, identify the design criteria and design constraints and include them in your written report.
Use your data to create a graphical and/or algebraic model that allows you to predict what length of tubing you need to produce each frequency in the scale.
Identify and record the variables that should be controlled. Describe how you designed your testing procedure to control for these variables.
Determine what changes can make small frequency corrections.
Explore how different methods of mounting the chime affect its sound. Consult additional resources (e.g., the library, a textbook, or the Internet) to obtain design ideas.
Design
Use your model to determine the design lengths you need to make your instrument. You will also need to design a way to support your resonant elements without dampening their vibration too much.
Prototype
Use appropriate tools, such as a pipe cutter, to create the resonant elements of your instrument. Assemble your prototype.
Test
Test your prototype by using the frequency spectrum to measure the resonance frequency of each chime. Also look at the frequency spectrum for the harmonic content of each chime.
Evaluate
Compare the actual frequencies to the design criteria. Identify the strengths and weaknesses of your prototype’s performance and document them in your written report. Determine any frequency adjustments that need to be made to the chimes and any changes that need to be made to your model.
Revise
Use your model to implement the design changes, such as removing material to raise a frequency. Implement the changes and test your revised design again. When you are ready, demonstrate the performance of your musical instrument by measuring the frequency of each chime.
Design a musical instrument
