Power cables and even batteries might become a thing of the past using a new technique that can transmit power wirelessly. Scientists lit a 60-watt light bulb from a power source 7 feet (2 meters) away with their new technique, with no physical connection between the source and the appliance. The researchers have dubbed their concept WiTricity," as in "wireless electricity." MIT physicist Marin Soljacic began thinking years ago about how to transmit power wirelessly so his cell phone could recharge without ever being plugged in. Scientists have pursued wireless power transmission for years - notably, eccentric genius Nikola Tesla, who devoted much energy toward it roughly a century ago. Soljacic and his colleagues devised WiTricity based off the notion of resonance. One well-known example of resonance can be seen when an opera singer hits the right note to cause a champagne glass to resonate and shatter. Two objects resonating at the same frequency tend to exchange energy efficiently, while interacting weakly with objects not resonating at the same frequency. Instead of sound, the MIT physicists focused on magnetic fields. Most common materials interact only very weakly with magnetic fields, so little power would get wasted on unintended targets. In their latest work, the scientists designed two copper coils roughly 20 inches (50 centimeters) in diameter that were specially designed to resonate together. One was attached to the power source, the other to a light bulb. The practical demonstration of their earlier theoretical work managed to power the light bulb even when obstacles blocked direct line of sight between the source and device.