What is Doppler Effect?
Doppler Effect
The Doppler Effect is the change in frequency or wavelength of a wave in relation to an observer moving relative to the wave source. It explains why a sound seems to change as an object moves closer or further away.
Overview
The Doppler Effect occurs when a sound source moves towards or away from an observer. As the source approaches, the sound waves are compressed, making the frequency higher, which is why a passing siren sounds different as it approaches compared to when it moves away. Conversely, as the source moves away, the waves are stretched, resulting in a lower frequency and a deeper sound. This phenomenon is not limited to sound waves; it also applies to light waves. For example, when a star moves away from Earth, its light shifts towards the red end of the spectrum, a change known as redshift. This principle helps astronomers determine whether stars and galaxies are moving closer to or further away from us, providing insights into the universe's expansion. Understanding the Doppler Effect is important in various fields, including astronomy, radar and medical imaging. In medicine, it is used in Doppler ultrasound to observe blood flow and detect abnormalities. By grasping how the Doppler Effect works, we can better understand wave behavior and its applications in everyday life.