What is the Doppler Effect and how does it work?

[TyroneBorr]

Can someone explain the Doppler Effect in simple terms? I'm especially curious how it relates to sound or light waves in everyday life.

 

[BarryRaymo]

The Doppler Effect is the apparent change in frequency or wavelength of a wave when the source or observer is moving. As the source approaches, waves are compressed, creating a higher frequency or pitch. When it moves away, waves are stretched, producing a lower frequency. It applies to sound, light, and electromagnetic waves.

 

[jarwish]

The Doppler Effect is the change in frequency or wavelength of a wave as its source and observer move relative to each other. When the source approaches, waves compress, increasing frequency (higher pitch); when it moves away, waves stretch, decreasing frequency (lower pitch). It applies to sound and light.

 

[Lucky]

The Doppler Effect occurs when a sound or light source moves relative to an observer. As it approaches, waves compress, increasing frequency and pitch; as it moves away, waves stretch, lowering pitch. It explains why a siren sounds higher when nearing and lower when passing by or moving away.