PBS
Nova: Booming Sands
PBS site takes a look into a mysterious phenomena as to why and how certain sand dunes produce mysterious noises. Contains a link to watch a broadcast segment of an expedition into the desert as well as a recipe for noisy sands.
PBS
Pbs: Nova Online: Galaxies, Clusters, and Superclusters
PBS site explores these building blocks of the universe as well as their various types and clusters.
PBS
Pbs: Nova Online: Moving Targets
Colorful PBS site explores the Doppler Effect and the reading of absorption lines.