What term describes the change in sound frequency due to the motion of the sound source relative to an observer?

The term that describes the change in sound frequency due to the motion of the sound source relative to an observer is the Doppler Effect. This phenomenon occurs when either the source of the sound or the observer is moving. When the sound source moves toward the observer, the sound waves are compressed, resulting in a higher frequency or pitch. Conversely, when the source moves away, the sound waves are stretched, leading to a lower frequency or pitch. The Doppler Effect is commonly experienced in everyday situations, such as hearing the changing pitch of a passing siren.

Refraction refers to the bending of waves as they pass from one medium to another and is not directly related to the motion of the source or observer. Diffraction involves the spreading of waves as they encounter obstacles or openings, which also does not pertain to the frequency change caused by relative motion. An oscilloscope is an instrument used to visualize electrical signals but is not related to sound frequency changes.