Physics of the Violin

How does the violin produce its unique sound? Despite more than a century of study, many important unsolved problems remain in the science of bowed string instruments. In particular, different bows have different tonal qualities, but how these qualities are related to the bow’s physical properties is poorly understood. A new project in our laboratory focuses on understanding how the bow interacts with the body of a bowed string instrument to generate sound. During playing, the bow hair is drawn against the string, causing the string to repeatedly stick to and be suddenly released by the hair, in a process known as stick-slip oscillation. These string movements then create vibrations in the body of the instrument, which radiate sound to the air. We have developed a machine for bowing the instrument with specific velocity, force, position, and other parameters while using a laser to measure the vibrations in the bow, instrument, and the resulting sounds. The student will use this device it to test models of coupling between the bow and instrument. Tasks will include data acquisition, computer programming and modeling, data analysis, and interpretation of results.