Light & Color

Watch Water Freeze

This exhibit consists of a horizontal glass plate wetted with a spray of water. The glass underneath the glass plate is refrigerated, causing ice crystals to form on the surface. The crystals are viewed through a polarized glass that reveals a beautiful display of shapes and color. Polarized glass is a special filter that makes ice look colorful. (These filters are the same ones found in polarized sunglasses used to cut glare.) Crystal structures and stresses show up as colors when viewed through polarized glass. Observers can watch the formation of spikes in new ice. When a water molecule freezes, it tends to line up with an already frozen water molecule. That's why newly frozen ice forms spikes. Sometimes they can also be seen in an ice cube tray in a freezer or on the edge of a winter puddle.