A goniometer measures angles by comparing the orientations of a sample, beam or viewing arm. An optical implementation can rotate a specimen and detector about a common center, measuring the directions of reflected, refracted or diffracted light.
For a prism experiment, a collimated input and a viewing telescope determine the angle through which the beam is deviated as the prism rotates. For a reflection experiment, the incident and viewing directions define the scattering geometry. Accurate centering matters: an off-center sample can move out of the measured beam as the arm rotates, changing signal strength for reasons unrelated to angular response.
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A goniometer is an instrument used to measure angles or to assess the range of motion in joints. It is commonly employed in fields such as physical therapy, orthopedics, and sports medicine to evaluate joint flexibility and to document changes in range of motion over time. There are several types of goniometers: 1. **Universal Goniometer**: This is a common type that has two arms and a protractor-like scale in the center.