At the point when we flip on a light switch, we close a circuit. The power streams from the electric wire through the light and back into the wire. At the point when we flip the switch off, we open the circuit. No power streams to the light. At the point when we turn a light switch on, power streams through a little wire in the bulb. The wire gets exceptionally hot. It makes the gas in the bulb gleam. At the point when the bulb wears out, the little wire has broken. The way through the bulb is no more.