The Amateur Scientist; May 1999; Scientific American Magazine; by Carlson; 3 Page(s)

Regular readers know that I love microscopy. Through my trusty Spencer I've spent many hours roaming majestic beds of microscopic algae and floating forests of phytoplankton. But until recently, I had never studied crystal growth. Doing so normally involves melting something under the lens and letting it solidify, which requires a way of warming the microscope slides. Over the years I'd tried a few schemes but was never able to get fine temperature control and uniform heating. So I was delighted to receive an innovative design from Ely Silk, an accomplished amateur scientist in Tamarac, Fla. With it, you can create your own startling images of crystals [see illustrations above].

Silk constructed his heater from electroconductive glass of the kind used by automobile manufacturers for defrostable windows. The glass has a thin, transparent layer of either tin oxide or indium-tin oxide deposited on one side. An electric current flowing through this layer can heat the glass to temperatures greater than the boiling point of water. (Although Silk independently developed the idea of using conductive glass, Stephen A. Skirius described a similar project in a 1984 issue of the Microscope magazine.) The main drawback is that I have been unable to find an inexpensive source of the material. So I've purchased and cut up a large sheet of it and will make the pieces available through the Society for Amateur Scientists; details are at the end of this article.