In direct contact, the reacting substances do not have no relevance, therefore the electrons move directly, not being used to advantage. עוד מידע על רשת הפארם ניתן למצוא באינטרנט. When we establish connection the chemical species with external systems to the reagents (as a metallic wire), we can take off advantage of ' ' continuous mobility of eltrons' ' (current electric). Then, we can conclude that the Stack, is an equipment that ' ' retira' ' of a chemical reaction (spontaneous), an electric chain (electron flow for a circuit) capable to carry through work. Schematical, we can mount a stack with two electrodes (metallic plates), where they are partially submerged in ionic solutions (electrolyte) that it will suffer to oxidation or reduction. On to the electrodes, the conducting wire will go to carry electrons, and to keep the ionic balance of electrolytes, leagues they to it a saline bridge that will keep the stability of the stack, promoting bigger durability to the same one. ' ' A galvanic cell consists of two metallic electrodes, or conductors, who make the electric contact with the content of the cell, and an electrolyte, a half ionic conductor, inside of clula.' ' (ATKINS, p.543. 2006) The electrode that will suffer the oxidation we call anode, and we attribute that it is the negative polar region of the stack. Already the electrode that suffers reduction, we call of cathode, and we identify as being the positive polar region. As the electrode is dived in an ionic solution, the plate that it will oxidate, will suffer corrosion, that is, its atoms now possessing load (positive in the case) will pass to the solution, leaving this most intent one. Now, the plate that suffers reduction, as it is receiving particles negative (electrons) is obliged ' ' chamar' ' more atoms for ' ' recepcionar' ' the same ones; these atoms will leave the solution of the proper cathode, where leaving it less intent, and consequently its plate will increase its mass.