1. The Doppler Effect

2. The Doppler Effect

3. The Doppler Effect
As illustrated on the previous slide, the Doppler Effect is basically a distortion of the wavelength of sound waves (or even electromagnetic waves) caused by relative motion between the source of a the sound and the one who hears it, the observer.

4. The Doppler Effect
If the source is coming toward the observer (vice versa), the
Wavelength appears smaller
Causing the frequency (pitch) of the sound to be higher
If the source is moving away from the observer (or vice versa), the
Wavelength appears longer
Causing the frequency (pitch) of the sound to be lower