(http://www.ionizationx.com/index.php?action=dlattach;topic=3175.0;attach=15050)
on the left side you see the molecule has its electrons attracted to the positive side the bonding electrons are represented paired together
on the right side after the molecules already aligned they receives a very sharp high voltage reverse pulse than the electrons of oxygen must re-arrange so changing the time share rate of the electron forcing them to be more likely into the hydrogen side basically depolarizing the molecule.... or neutralizing the dipole attraction force
on the drawings the red is positive and blue negative