Sunday, 29th June 2014

Since yesterday I am working on setting up of an experiment to study Doppler effect in sound.

If the source of sound or the detector is in motion relative to the medium of propagation, the frequency of the waves that are emitted  appears to be changed due to Doppler Effect. This is an interesting experiment at Higher Secondary level.

The experimental set-up is ready. I have used the linear air track and fixed the source of sound on the glider. the emitted sound waves can be detected by a microphone fixed in ExpEYES. We can determine the original frequency of the source using ExpEYES and then the source is set in to motion and again frequency is determined.  A photo-gate is used to measure the speed of the source.

The apparent frequency is related to the speed and the original frequency. The experimental results can be verified by theoretical calculations.

Practical Application:

  1. General Study of Doppler Effect
  2. For different frequencies, measure the Doppler shift with different velocities of the sound emitter. Compare the theoretical and experimental results.


The python code required for measuring frequency and also to determine speed using photo-gate  is already written. I could get good results in my experimental trials.

Tomorrow I will work on developing a separate code for a simple GUI for this experiment.

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