Doppler Effect Worksheet

Doppler Effect: Sound and Motion

Read each question carefully and answer to the best of your ability. Show all your work for calculation questions.

The Doppler Effect

The Doppler Effect describes the change in frequency or wavelength of a wave (like sound or light) in relation to an observer who is moving relative to the wave source. When a source of sound waves approaches an observer, the waves are compressed, leading to a higher perceived frequency (higher pitch). Conversely, when the source moves away, the waves are stretched, resulting in a lower perceived frequency (lower pitch).

1. What phenomenon explains why the pitch of an ambulance siren changes as it passes you?

2. When a sound source moves towards an observer, the perceived frequency of the sound waves will:

3. The Doppler Effect is observed when there is relative motion between the wave source and the  .

4. When a police car with its siren on drives away from you, the pitch of the siren will sound   than when it was approaching.

5. The Doppler Effect only applies to sound waves, not light waves.

6. If both the source and the observer are moving in the same direction at the same speed, no Doppler Effect will be observed.

7. Describe one real-world application of the Doppler Effect in technology or medicine.