Flip a switch and something flows instantly through the wire — not water, but electrons, tiny charged particles nudged along. Current is that flow of charge, the invisible river that lights the bulb.
Electrons on the move
Matter contains tiny charged particles. Electrons carry negative charge and can drift between atoms in certain materials. Electric current is simply the flow of these charges through a material, measured in amperes (amps) — one amp is a huge number of electrons passing a point each second.
In conductors like copper, electrons move freely, so current flows easily. In insulators like rubber or glass, electrons are locked in place — which is exactly why wires are copper wrapped in plastic.
For current to flow you need a complete loop — a circuit — from one terminal of a source (like a battery), through the wire and device, and back. Break the loop and the flow stops instantly. That is all a light switch does.
- Imagine (or build) a simple circuit: battery, bulb, and two loose wire ends with a gap.
- Bridge the gap with different objects: a metal spoon, a plastic ruler, a coin, a pencil's graphite tip, a rubber band.
- Predict for each whether the bulb will light before you test it.
- Sort your objects into conductors and insulators based on the results.
What you should see: You classified everyday materials by whether they let current complete the loop — and probably found graphite is a surprising conductor.