Building your own xylophone involves studying the math and physics used to create the different tones. You can make a xylophone from a copper pipe by determining the length needed to form different pitches. This requires calculating the equations related to the transverse vibrations of the pipe. As a science project, you can build a xylophone with eight pipes, forming any scale of your choice, and state how the lengths of these pipes would need to be altered to make a different scale.
Simple drinking straws can be transformed into a musical instrument for a science fair project studying the physics of sound production and the science behind sound waves. The straws are made into a reed, such as that of an oboe, and cut at different lengths to create different pitches. You can then position the straws together in a holder to create a musical instrument. The project is relatively simple, as the science involved is not very complex, and the instrument is easy to construct.
When you blow into the top of fluid-filled bottles, a musical note is created. A science project related to this studies resonance of closed-end air columns. Examples of real musical instruments using this method include the organ (through its pipes), flutes and brass instruments. By measuring the different levels of a fluid in bottles and tuning with a chromatic tuner, you can create a number of different musical notes. You can include in your project what the relationship is between fluid level and pitch.
Wine glasses produce sound when the rim is rubbed with a dampened finger. The principles behind how an armonica, or glass harmonica, produces sound are the same as for the wine glass. For a science project, you would research vibration, frequencies of musical notes and resonance. The tone of the wine glass is affected by the amount of liquid in the glass, and you must use just the right amount of pressure and moisture to produce any sound at all.