Sinus Rhythm (labeled) Advanced 10/01/2013 Cave of the Crystals Intermediate 09/27/2013 Iron filings Intermediate 09/03/2013 Thunderstorm Beginner 08/26/2013 Sound Barrier Intermediate 06/18/2013 Aurora Borealis over Canada Beginner 04/29/2013 Schematic View of Van de Graaff Generator Intermediate 06/28/2012 Ferrofluid on a Glass Plate Intermediate 06/28/2012 Surface Waves of Water Advanced 06/28/2012 Crab Nebula Intermediate 06/25/2012