MORE ABOUT ELECTRIC POWER: Wiggling Current

The current that flows through a battery always flows in the same direction. It is called direct current, and is abbreviated DC. The current that travels from a power plant to your house and back is called alternating current, and is abbreviated AC. Within the wires of the big circuit, alternating current flows first in one direction and then the other, like a rapid vibration. The electrons within the wires don't move very far because they change direction 120 times per second. It is the AC vibration that travels through the circuit and delivers energy where it is needed.

NEXT: High Voltage