| Oscillations and Waves
> Waves > Reflection and Refraction of Sound
Waves > Impedance and Dispersion |
DCS# 3B25.55 |
| space phones | MK |
| laptop
with Raven Lite software |
206 |
| laptop microphone |
202-07-E1 |
Support the phones far enough apart so that neighboring coils of the spring aren't in contact with each other. Tap one horn. The sound heard at the other end is a chirp descending in pitch.
The software will display the waveform and spectrogram in real time. The graphs below, for this sound file, show the initial tap and several echoes. From the spectrogram, it can be seen that the higher frequency components reach the microphone before the lower frequencies. The sound can be replayed at half speed to make the change in pitch easier to hear.
Here is the waveform graph, rescaled to show a single chirp.
American Journal of Physics 55, 130 (1987).
Erratum: ‘‘Slinky whistlers’’ [Am. J. Phys. 55, 130 (1987)]
American Journal of Physics 58, 916 (1990)
