This hypothesis suggests that ball lightning consists of vaporized silicon burning through oxidation. Lightning striking Earth's soil could vaporize the silica contained within it, and somehow separate the oxygen from the silicon dioxide, turning it into pure silicon vapor. As it cools, the silicon could condense into a floating aerosol, bound by its charge, glowing due to the heat of silicon recombining with oxygen. An experimental investigation of this effect, published in 2007, reported producing "luminous balls with lifetime in the order of seconds" by evaporating pure silicon with an electric arc. Videos and spectrographs of this experiment have been made available. This hypothesis got significant supportive data in 2014, when the first ever recorded spectra of natural ball lightning were published. The theorized forms of silicon storage in soil include nanoparticles of Si, SiO, and SiC. Matthew Francis has dubbed this the "dirt clod hypothesis", in which the spectrum of ball lightning shows that it shares chemistry with soil.