band theory in a sentence

Examples

1. The properties of semiconductors are best explained using band theory, as a consequence of a small energy gap between a valence band ( which contains the valence electrons at absolute zero ) and a conduction band ( to which valence electrons are excited by thermal energy ).
2. its true that the " sea of eletron " model works but I can't combine my understanding of the band theory with model, specially when its emphasized that the transition of one electron from one band to the other doesn't mean that it actually " moves " somewhere else . well, my question is what DOES happen-- talk ) 20 : 12, 9 June 2011 ( UTC)