"We took a tupperware container filled with flour, tipped it back and forth until cracks appeared, and it produced 200 volts of charge," said Rutgers University researcher Troy Shinbrot. "There isn't a mechanism I know that can explain this. It seems to be new physics." They repeated the experiment with other granular materials (like those in soil) and got the same results. Shinbrot explained in an email that although it did produce high voltages, there was "no current to speak of, so there's no power to be obtained."