" Finally, the theory explained why the resistance drops so abruptly at a certain temperature. It’s much the same reason that water freezes suddenly at 0 degrees Celsius. Both processes are phase transitions, victories of self-organization over random jittering. At the freezing point, water molecules calm down just enough to allow their attractive forces to bond them into a crystal. Similarly, at the superconducting transition temperature, the atomic lattice calms down just enough to allow electrons to form Cooper pairs and coalesce into a Bose-Einstein condensate. In both cases, a fraction of a degree drop in temperature makes all the difference. "
― Steven H. Strogatz , Sync: The Emerging Science of Spontaneous Order