How Electric Currents Flow From Batteries to Light Bulbs

Electricity must flow in a complete circuit to cause a filament to light.

Batteries create small chemical reactions that are activated when metal plates come into contact. When these plates come into contact, electricity can flow in a circle and cause the battery to release energy, allowing it to flow to its source, such as the filament of a light bulb.

Batteries

Batteries contain chemicals that react through reduction/oxidation chemistry. They transfer electrons over a salt bridge, creating electricity during the reaction. However, they must have a complete circuit before electricity begins to flow.

The Filament

Electric lights function by passing electricity through a filament. The filament is a tiny piece of metal with a high resistance to electricity. As the electricity enters the filament, it heats up and produces light.

The Circuit

In order for the electricity from a battery to reach the filament and continue flowing, a complete circuit must be created. This means that the electricity must be able to flow back to the place where it originated. In the case of batteries and a light bulb, the switch will connect a metal plate to the back of a battery, creating a complete circuit and allowing the electricity to flow freely to the filament and back to the battery.

References

• Washington University: Chemistry of Batteries
• Michigan State Sciences: How a Light Bulb Works
• Swanson Tec: Elecriticity Basics