This Lichtenberg figure or 'electrical tree' was formed inside a 1.5" cube of polymethyl methacrylate (PMMA) using a 3 MeV electron accelerator.
Lichtenberg Figures with a Van de Graff GeneratorLichtenberg Figures in WoodQuestions About Making Lichtenberg Figures
Anne Marie Helmenstine, Ph.D. Chemistry Guide
©2013 About.com. All rights reserved.