Oscillations and Waves > Waves > Reflection and Refraction DCS# 3B30.03
PHASE OF REFLECTED SOUND WAVE

reflected pulse

APPARATUS
brass tube 202-06-D
rubber mallet
 202-05-B
cork
 101-01-A1
team labs microphone
 202-07-E3
team labs interface 202-07-E3
laptop 206

DESCRIPTION
Strike the cork with the rubber mallet to produce a sharp pulse.  The output of the microphone vs time is displayed on the computer.  The pulse reflected off the open end is shown to be inverted, whereas the reflection from the closed end is not.  One can also use this set-up to determine the speed of sound in air.

NOTES

Image above was made using pipe with one closed end.
Image below was made using pipe with two open ends:


 
REFERENCES

AJP 52(9),854
TPT 41(1), 12.
Why does sound bounce off the open end of a tube? by Paul Doherty