Wireless Energy Lights Bulb from Seven Feet Away

Physicists vow to cut the cord between your laptop battery and the wall socket—with just a simple loop of wire

By JR Minkel, Scientific America.com

If you thought wireless Internet made life convenient, try wrapping your mind around wireless power. Researchers have successfully lit a 60-watt light bulb by transferring energy through the air from one specially designed copper coil to the bulb, which was attached to a second coil seven feet away [see image at right]. The ultimate goal: to shrink the coils and increase the distance between them so that a single base station emitting "WiTricity," as the inventors refer to the effect, could power a roomful of rechargeable gadgets, each containing its own small coil.

EUREKA! WIRELESS LIGHT BULB
demonstrates a new approach for transmitting
power through the air between two coils
of copper wire, even when separated by an

obstruction [bottom].

Physicists have known for more than a century that a moving magnetic field produces an electric field and vice versa in an effect called electromagnetic induction, which makes motors turn and allows your, say, electric toothbrush to recharge when placed on its base station. But induction normally works only at very short distances, which is why the toothbrush and base station must touch.

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