In what context is the Doppler effect commonly used?

The Doppler effect is commonly used to determine sound frequency changes, which occurs when there is relative motion between a sound source and an observer. This phenomenon explains how the frequency of sound waves changes based on the movement of the sound source toward or away from the observer. For example, as a vehicle approaches, the sound waves compress, resulting in a higher pitch (frequency). Conversely, as the vehicle moves away, the waves are stretched, producing a lower pitch.

This principle is widely utilized in various applications, including radar and lidar technology, where it helps in measuring the speed of moving objects by analyzing the shifts in frequency of the returned waves. The understanding of the Doppler effect is essential in fields like meteorology, astronomy, and acoustics, where frequency changes are vital for accurate measurements and observations.