Fascinating plasma sculpture at the Compton GalleryIt's all based on plasma physics, but you don't need Maxwell's equations. You can also ignore the obscure, stuffy statements about "kineticism" on the plaque at the gallery entrance. The beauty of plasma sculptures is easy to enjoy. They are technological devices, but they appeal to a simple, childlike sense of wonder at nature.
Plasma "sculpture," invented by Bill Parker '74, is not sculpture in any usual sense. It is best described as controlled lightning. A plasma sculpture is a hand-blown glass form, usually a sphere or tube, containing a mixture of noble gases. High-voltage, high-frequency signals ionize the gas and drive currents through it, and the paths of the current glow with light emitted by excited atoms. The sculpture appears to be filled with threads of light wandering across the face of the glass. The color and appearance of the light vary from one sculpture to another, depending on the composition of the gas mixture and the programming of the signal generator. Touching the glass is safe, and spectacular, since it causes the strands of light to cluster at your fingers (your body provides an electrical ground).
The Compton Gallery contains about a dozen plasma sculptures standing in darkened rooms, so that there is little reflection from the glass and the patterns of light seem to be suspended in space. The high-voltage circuitry is well hidden; nothing distracts you from the coruscating display. You can just watch the currents, which may look like rippling water or like a tangle of silvery hair whipping back and forth. Or you can interact with them, touching the glass and turning knobs which change the way the patterns move.
Plasma is an unfamiliar substance, yet the flickering bolts of light in a plasma sculpture are often reminiscent of familiar phenomena in nature, engaging and tantalizing the imagination. Some resemble boiling cauldrons of red tentacles or colonies of lost searchlights; the soft green tendrils of another sculpture look like seaweed drifting on the tide. The bulb at the center of the spherical sculptures, which broadcasts the high-frequency discharge, often brings to mind an eyeball covered with blood vessels or the stormy surface of a star.
Both students and visitors should be sure to see this exhibit. I hope MIT keeps at least one plasma sculpture permanently.