Microwave sparks (IMAGE) University of Wyoming Caption In a microwave oven, sparks are generated inside a glass vial containing coal powder and copper foil as part of an experiment by University of Wyoming researchers. They successfully converted the coal powder to nano-graphite, demonstrating a novel and inexpensive coal-conversion technology. Credit Chris Masi Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.