Why Does My Doppler Effect Experiment Show Different Results from Theory?

[fermion314]

Homework Statement

Hello,

I did an experiment a couple of weeks ago to measure the doppler-effect. I have used a pendulum with a microphone attached to it. At one end i put a speaker which produces a sound with f =440 hz. T of the pendulum = 1,86 s. Vmax = 1,69 m/s. But if i try to measure T in my diagram it doesn't come near the solution i get with the doppler-equations.

I have done this in my diagram:

1800 - 1100 = 700 ms

7T = 700 ms => T = 100 ms = 0,1 s

I get f ≈ 10 hz (see doppler-effect2)

Homework Equations

I used fw=fb(1 + (vw/v)) and fw=fb(1-(vw/v)) and i got fw = 442 hz when the microphone is moving towards the speaker and fw = 437 hz when it moves away from it.

The Attempt at a Solution

I have tried to change the time-axes with a other timescale. But i don't think that's the solution. I know v is not constant. I don't see a way to link my experiment with the theory.

I hope someone can help me with this.

 

[anathema]

Hi there,

Thank you for sharing your experiment and calculations. It seems like you are on the right track, but there may be some factors that are affecting your results. First, it is important to make sure that your measurements are accurate. Double check your calculations and make sure all units are consistent. Also, consider the accuracy of your equipment and any potential sources of error.

Next, it is important to consider the assumptions made in the doppler equations. One key assumption is that the source and observer are moving relative to each other at a constant velocity. In your experiment, the pendulum is swinging back and forth, so this may not be the case. Also, the speed of sound can vary depending on factors such as temperature and humidity, so this may also affect your results.

To improve your experiment, you could try using a more precise and stable pendulum, or use a different method to measure the frequency of the sound. You could also try varying the speed of the pendulum and see how it affects the results.

I hope this helps and good luck with your experiment!