To test the Doppler effect, use a moving platform with a sound source and detector. Change the distance or speed to observe frequency shifts—higher as the source approaches (blue shift) and lower as it moves away (red shift).
Experiment to Test the Doppler Effect:
Materials:
1. Source of sound (e.g., a speaker)
2. Detector (e.g., a microphone)
3. Platform for the source and detector (e.g., a moving cart or vehicle)
4. Sound generator (e.g., smartphone or computer)
5. Distance measuring tools
6. Speed measuring tools (e.g., radar gun or GPS)
Procedure:
1. Set up the source and detector on a platform that allows controlled movement.
2. Connect the sound generator to the speaker and play a constant-frequency sound.
3. Record the frequency of the emitted sound when the source and detector are stationary (baseline).
4. Gradually move the platform away or towards the detector while emitting the sound.
5. Measure the changing frequency detected by the microphone as the platform moves.
6. Record the distance between the source and detector at various points.
Variable:
The variable changed is the relative motion between the source and detector. This can be achieved by altering the distance between them or changing their relative velocities.
Expected Observations:
As the source approaches the detector, an observer would perceive an increase in frequency (higher pitch), indicating a blue shift. Conversely, when the source moves away, a decrease in frequency (lower pitch) would be observed, indicating a red shift. This aligns with the Doppler effect predictions, demonstrating the frequency shift due to relative motion.