* Power Source: Electricity is the energy that can be used to power light bulbs and appliances. It's often generated in power plants and then transmitted through wires.

* Closed Circuit: A closed circuit is a complete path for electricity to flow. This flow happens because of an electrical potential difference (voltage) that drives the electrons through the circuit.

* Why Closed Circuit is Essential: If the circuit is broken (open), the electricity cannot flow, and the light bulb or appliance won't work.

Think of it like this:

Imagine a river. The water (electricity) needs a continuous path (closed circuit) to flow from its source (power source) to the destination (light bulb or appliance). If there's a dam (open circuit) in the river, the water cannot reach the destination.