HOME GADGETS EXPLAINED

We often take the technology that keeps our homes running for granted, but here's how they actually work

- WORDS DUNCAN GEERE

ENERGY-SAVING BULBS MAKING GAS GLOW

Traditional light bulbs work by passing a current through a thin wire. The wire then heats up so much that it glows and gives off light. That takes a lot of energy, and much of it is wasted as heat. An alternative, the fluorescent lamp, became popular in 1938. Today's energy-saving light bulbs, called compact fluorescent lamps, or CFLs, are merely small cousins of the fluorescent tubes you see in offices. They're filled with a gas that releases ultraviolet photons - particles of light - when an electrical current is passed through them. The inside of the tube has a coating of phosphors. When the photons hit the inside of the tube, the ultraviolet light is converted to visible light and your room lights up. They are more efficient than traditional bulbs and work out cheaper in the long run.

More recently, these bulbs have begun to be replaced with LEDs, which generate light using yet another method - the movement of electrons in a semiconductor. These are safer, longer lasting and more energy efficient than CFLs.

WI-FI SENDING PULSES THROUGH THE AIR

Beaming information through the air seems magical, but we've been doing it even since our ancestors started communicating with smoke signals.