Presented by Dave Besson, Kansas University. Water, atypically, expands when it freezes (lest all freshwater lakes freeze solid in the winter). Moreover, although snow is white, in its packed form, ice is among the most transparent solids known, from wave-lengths as small as hundreds of nano-meters to several meters. We’ll discuss the remarkable properties of ice, which have implications for disciplines as varied as climatology and particle astrophysics at the South Pole.