Crave Talk: Scientists invent power without wires

If you go to Disney's Epcot Center and ride the Carousel of Progress you'll see that when electricity first arrived in homes, the concept of neat wiring didn't exist. The Carousel shows a home from early last century where electrical wiring is strung across rooms like giant strands of fresh spaghetti drying in the midday sun.

There was little concern for safety. If you wanted an electric light on your ceiling, you just ran a length of wire up there and it would droop precariously into the room; a lethal skipping rope carrying the century's most important invention. You might turn your back to admire a friend's Model T passing the window, and before you knew it, little Timmy was wrapped up in a deadly wire, involuntarily jazz-handing and foaming at the mouth.

We've come a long way from there, and modern homes have concealed wiring. But scientists have now discovered a way to eliminate wires from the home entirely. The technology behind this invention was demoed by Professor Soljacic at the American Institute of Physics in San Francisco yesterday. No longer will you have to plug your television or laptop into the wall, and no longer will the Hoover run out of slack just before you reach that critical dust patch under the bed.

The method relies on a phenomenon called 'resonance'. The basic idea behind the science of wireless electricity will be familiar to musicians. You've probably noticed that if you play music on a stereo system in the same room as an acoustic guitar, the guitar strings will occassionally vibrate when the music hits the same frequency as a string is tuned to. This is because two objects of the same frequency will vibrate in sympathy. In fact, you can make a guitar string vibrate by singing the same note into the sound hole (endless fun).

Scientists pioneering wireless electricity are using the same priniciple to send electricity though the air. Instead of sound waves, they're using electromagnetic 'long-lived resonances' which do not radiate like traditional electromagnetic waves (radio waves, for example). These can accurately send trails of electricity invisibly across rooms, or so it seems.

The system establishes a very efficient pairing of electromagnetic resonance between the power source (the mains electricity) and the target object (your laptop or television). You can then stay connected to the power socket through the pairing of electromagnetic resonances. The power source 'sings' the right note and your 'instrument' vibrates in sympathy.

Nikola Telsa (played by David Bowie in current box office hit The Prestige, though not very much like him in real life) experimented with a similar concept in the late 19th Century, except with a more scary lightning effect. He built a giant tower in New York for the purpose, but -- luckily for the people of New York, perhaps -- ran out of money to complete the project.

All this sounds fantastic and pioneering, a return to the age of the great inventors, but how safe is it to beam electricity through the air? What if little Timmy's brain happens to resonate at the same frequency as your television? Will he get 240 volts beamed into his head? Will you be sat at Sunday lunch, raising a forkful of tasty roast beef to your mouth, only to discover it was resonating at the same frequency as your hairdryer when it explodes in a fireball?

Whatever happens, this sounds like an utterly wonderful technology that will either eliminate wires from the home, or make life so exciting it doesn't matter. -Chris Stevens