How Does Electricity Light a Bulb?

What You'll Learn

• Electricity is moving electrons through a wire
• A light bulb has a thin wire called a filament inside
• When electricity flows through the filament, it heats up
• The hot filament glows and gives off light
• LEDs make light a different way using special materials
• A closed circuit is needed for electricity to flow

Words to Know

Electricity

Energy carried by moving electrons

"Electricity flows through the wire."

Filament

A thin wire inside a bulb that glows when hot

"The filament got hot and lit up."

Circuit

A complete path for electricity

"The circuit was closed when I flipped the switch."

Electron

A tiny particle that carries electricity

"Electrons moved through the wire."

Check What You Learned

Fun Facts

• Electricity is the flow of electrons through a conductor

  Source: Britannica

• An electric circuit must be closed for current to flow

  Source: Khan Academy / physics

• Incandescent bulbs contain a tungsten filament that heats to 2,000–4,000°F (1,100–2,200°C) and emits visible light

  Source: Energy Star / DOE

• The filament glows because of incandescence — light emitted by a heated object

  Source: physics textbooks

• LEDs produce light through electroluminescence in a semiconductor material, with much less heat

  Source: DOE

• Incandescent bulbs convert only about 5% of energy into visible light; LEDs convert ~20-30%

  Source: DOE