Science Lab Experiment: Train of Waves
Demonstration Train of Waves
Object: To determine some characteristics of sound.
Materials: bell, battery, rubber sheeting, elastic bands, tack,
cardboard tube, small end of eraser, string
Method: The rubber sheeting was fastened to the tubing using elastic bands.
A tack was suspended close to one end of the tube (Diagram A).
The other end of the cardboard tubing was connected to the bell
as shown (Diagram B).
Observations:The tack when suspended close to one end of the cardboard tube
was seen to move quite violently, when the other end was plucked.
When the hammer of the bell was connected to the rubber sheeting
of the second cardboard tube and rung, the tack was seen to move
back and forth rapidly.
Conclusions: The movement in both cases was due to the "train of waves" set up
by the change in air pressure within the cardboard tubes. The
vibrations of sound travel in similar waves of compression and