Electricity & Simple Circuits

Electricity is the movement of tiny particles called electrons through a material that lets them flow. When electrons move in a complete loop, they form an electric current. We use that current to power lights, screens, motors, and almost every device you can think of.

Parts of a Simple Circuit

• Battery — the energy source. It pushes electrons through the circuit.
• Wire — a thin metal path that carries the current from one part to the next.
• Switch — opens or closes the circuit, turning the current on or off.
• Bulb — the load. It changes electrical energy into light and a little heat.

How the Circuit Works

1. The battery pushes electrons out of its negative end.
2. Electrons travel along the wire toward the switch.
3. If the switch is closed, the current keeps moving and reaches the bulb.
4. The bulb glows because the current heats its thin filament.
5. Electrons return to the battery, completing the loop.

Series vs Parallel Circuits

• Series circuit — all parts are on a single loop. If one bulb breaks, the whole circuit stops.
• Parallel circuit — each bulb sits on its own branch. If one branch breaks, the others keep working.
• Most homes use parallel wiring so a broken bulb does not switch off the entire room.