Electrodes

Electrodes, anodes, cathodes, and salt bridges.

An electrode conducts electrons into and out of a solution. There are two specific kinds:

Anodes
Cathodes

Oxidation occurs at an anode. Therefore, anodes have a negative charge. Reduction occurs at a cathode. Cathodes have a positive charge. This pops up a lot. Another quick table for you to memorize:

Anode Oxidation

Cathode Reduction

Anode	Oxidation
Cathode	Reduction

If we have two separated containers, each containing part of the chemicals that are needed for a redox reaction, and we put electrodes in each container, then we will get a current flow, provided there is a salt bridge linking the two solutions. A salt bridge keeps the ion charges in the cell compartments balanced. An analogy can be found in our weather system. When it rains, the water collects in rivers and makes its way back to the ocean. Once there, the sun evaporates the water, which comes back down again as rain. In our chemical system, the salt bridge acts like the sun. Without the saltbridge, we would not be able to have a current flow, because the negative ions would not have a way to move from one solution to the other. In both cases, without a method of transport, there could not be a cycle. These parts together form the basis of the battery, or electrochemical cell.