For example, a drum beat, the snap of a breaking stick, a truck rumbling by on a street. Discuss the vibration one can feel in the speaker of a stereo. Set up the demonstration of a bell in a vacuum. With the bell ringing, pump the air out of the bell jar, and then allow the air to fill the system again. Discuss why the sound of the bell gets fainter until no sound can be heard.
Seismic waves transmit the energy of an earthquake.
Research earthquakes to determine the types of waves made. Traditionally, soldiers break step when crossing a bridge. In the 1800s a group of soldiers crossing a bridge in step set up a vibrational pattern that caused the collapse of the bridge. Research this incidental bit of history under the topic of bridges or vibrations.