What principle does the strain gauge use to record lip and jaw movements?

The strain gauge operates based on the principle of electric resistance. This device is specifically designed to detect small changes in shape, which occur when the lip and jaw move. When these structures deform due to movement, the strain gauge senses this change, which alters its electrical resistance. The relationship between the strain experienced by the material and the corresponding change in resistance allows for precise measurement of the movements of the lips and jaw.

The sensitivity of electric resistance to physical changes makes strain gauges particularly effective for applications that require accurate tracking of movement. This principle is widely utilized in various fields, including biomedical engineering and speech science, where understanding articulatory behavior is crucial for analyzing speech production. The other options, while exploring different technologies, do not relate to the specific mechanism by which a strain gauge functions.