electrodes

Electrodes are the two conducting parts of an electric cell through which electricity enters or leaves the cell.

• In a voltaic cell, electrodes are usually made from two different metals, such as zinc and copper. They are placed in an electrolyte, but they should not touch each other directly.
• The chemical reactions at the metal surfaces separate electric charges. This creates a difference in electrical potential, like a tiny “push” that can drive current through a wire.
• One electrode becomes the negative terminal and supplies electrons to the outside circuit. The other becomes the positive terminal and receives electrons after they travel through the circuit.
• Think of electrodes as the cell’s two doorways for electrons: electrons leave through one doorway, travel through a device such as a bulb, and return through the other.
• In a lemon cell, a copper strip or wire and an iron or zinc nail can act as electrodes. The lemon juice helps the chemical reactions happen, but the metals provide the pathways for electrons.

The choice of electrode metals matters: metals that react differently can produce a larger voltage and a stronger electrical effect.