The Lorentz-Drude theory explains the motion of electrons in metals. It postulates that: 1) The outermost electrons of metal atoms are weakly bound and move freely inside the metal, behaving like gas molecules. 2) These "free electrons" are in thermal equilibrium and obey Maxwell-Boltzmann statistics. 3) When an external electric field is applied, the free electrons accelerate in the opposite direction but collide with the metal ions, preventing an increase in velocity. The electrons drift at a constant velocity.