Mohammad Al Faruque of the Advanced Integrated Cyber-Physical Systems lab. "According to the fundamental laws of physics, energy is not consumed; it's converted from one form to another -- electromagnetic to kinetic, for example. Some forms of energy are translated in meaningful and useful ways; others become emissions, which may unintentionally disclose secret information," he explained, in a complicated way of saying making stuff = sound clues. Like, you could fake a chair by listening to the chipping sounds of a carpenter.