The weapon used by the jawa surrounds r2-d2 with a strong electric field, which is created by a large imbalance of electrons chemical bonds neutrons the force

If there is balance between the positively charged protons and the negatively charged electrons, the two chargers are neutralized. an imbalance of protons and electrons leads to imbalance of charges. electrons are then able to move, resulting to the  formation of an electric field. 

On the galapagos islands charles studied finches