Portable light sources have been one of the most evolving inventions in history — from the primative torches and oil lamps of yesteryear, to today’s battery-powered flashlights and headlamps. But through it all, most of these illuminating tools have required an outside energy source that would deplete when needed the most.
But now, thanks to one particularly enlightened 15-year-old girl from Canada, your next flashlight just might be powered by the heat from your hand. Introducing, the thermoelectric ‘Hollow Flashlight' — submitted for the Google Science Fair.
— Teenager invents a flashlight powered by the heat from your hand