Pendulum Wave Demonstration (16 bowling balls hung from a wooden frame, touching metal tubes which give sounds as they pass their lowest point); amazing constellations at 1:14 and 2:17.
Jeff Goodman, teacher at Appalachian State University in Boone, NC, USA.
CC BY-SA 1.0
<a rel="nofollow" class="external free" href="https://www.youtube.com/watch?v=YhMiuzyU1ag">https://www.youtube.com/watch?v=YhMiuzyU1ag</a>