Definition
Doppler Effect is the observed change in the frequency or wavelength of a wave when the source of the wave is moving relative to the observer.
Why It Matters
It is used in radar speed guns, weather tracking, and tracking the expansion of the universe (redshift).
Core Concepts
- The Doppler Effect:
- Approaching: Waves are “compressed,” resulting in a higher observed frequency (Blue Shift for light).
- Receding: Waves are “stretched,” resulting in a lower observed frequency (Red Shift for light).
- Bow Waves: V-shaped waves produced by a source moving faster than the wave speed in a medium (e.g., a boat on water).
- Shock Waves: Cone-shaped waves produced by a source moving at supersonic speeds (faster than sound).