Electricity is the flow of electric charge. It powers lights, motors, computers, and almost everything in modern life. The word comes from the Greek elektron, meaning amber, because the ancient Greeks noticed that rubbing amber attracted small objects. Today, electricity is generated in power plants, transmitted over long distances, and distributed to homes and businesses. It is one of the most versatile forms of energy, easily converted to heat, light, motion, or sound.

Electricity is not a substance. It is a phenomenon. It arises from the presence and motion of electric charge. In a wire, electrons drift slowly, at about a millimeter per second. But the electric field that pushes them travels at nearly the speed of light. That is why a light comes on instantly when you flip a switch, even though the electrons themselves move slowly. Electricity can be generated by moving a conductor through a magnetic field, by chemical reactions in a battery, or by sunlight in a solar cell. It can be stored in batteries, capacitors, and fuel cells.

Electricity facts

• Definition. Flow of electric charge.
• Generation. Magnetic induction, chemical reactions, solar cells.
• Transmission. AC for long distances, DC for some applications.
• Storage. Batteries, capacitors, fuel cells.
• Units. Volts, amps, ohms, watts.

Electricity is not the same as energy. Electricity is a way of transferring energy. The energy itself comes from the source, whether coal, gas, wind, or sunlight.