Doppler effect? Experiment...

Question

I have to design and perform an experiment that demonstrates the Doppler Effect. Any ideas on how to do this? because i dont..... Any suggestions at all would be greatly appreciated, Oh and I have to do this Quantitatively...

The Doppler Effect (Doppler Shift) is the apparent frequency change when there is relative motion between a source of waves and an observer. It has been suggested that i could do this with sound or water waves, but how?

Answer 1

You need to set up some sort of travelling sound source. I think circular motion is your best bet. Get something that makes noise, a constant beep would be best. Tie it firmly to a bit of rope of about 1.5 meters. Measure out 1 meter and mark it. this is where you will swing the thing from. In other words the center of the circle, easier to do calculations.

Measure the frequency of the sound while stationary.

Then get a metronome or use a click track on a music program and try to swing the thing so that it passes the same spot when the click happens. With this you will be able to calculate the speed it is travelling at.

Next measure the frequencies of the travelling sound and you will get a max and min, max as itcome colser to the recording device and min as it goes away.

Answer 2

If you had a source of sound at a specific frequency say a 1 kHz sine wave coming from a source (like a computer). Then you could take a microphone by the cord and swing it around in a big circle really fast. If you record the 1 kHz through the microphone you will find that it would be changing in time at teh frequency that you were swinging the microphone around. You can find out what the frequency is by using a computer program that has some kind of frequency diagnostic in it. I assume you could get one for free from somewhere online (spectrum analyzer/oscilloscope program). From that data you would be able to determine how fast the microphone was going while you were spinning it, also the frequency you were spinning it at. From those you could also figure out how long the cord between your hand and the microphone was too.

Anyways, I think that would be a cool way of showing the doppler effect and also it would be pretty easy.

edit:

Ooops, I left for a while without submitting. That guy above me had a easier way of doing the same thing.

Answer 3

You could accelerate excited ions through an electric field.  The difference in wavelength between those and ions at rest would demonstrate the doppler effect

Answer 4

cant you guys do something simple

try getting your friend to drive a car towards you and then go past At a constant speed (noting the speed) blowing the car horn

and tape the sound as he goes past

Quantitatively? hmmmm can you get access to frequency meter?

good luck