This Flashlight Is Powered by the Touch of Your Hand/a>
re’s a little known fact: The human body, at any given moment, produces energy equivalent to a 100 watt light bulb. In that sense, we’re always wasting our energy—energy that can be used to, well, power a light bulb. It’s this line of thinking that led a 16 year old to invent the first flashlight powered entirely by body heat.
Ann Makosinski’s “Hollow Flashlight” isn’t the only manually-powered light out there. But whereas other products generate energy with shaking or even hand cranking, her award-winning prototype shines the moment you pick it up.
"I thought, why not body heat?" she told The Oregon Herald. "We have so much heat radiating out of us and it’s being wasted."
Not until recently did researchers look into ways to capture excess body heat as a means of powering devices like hearing aids and pacemakers. Four years ago, engineers in Sweden figured out a clever (and somewhat sneaky) way to siphon the biothermal energy of passengers at a central train station to heat nearby office buildings. Still, much of the challenge in developing these technologies has to do with the fact that electricity produced from residual thermal energy is usually too weak to run most common devices. The inner ear, for instance, produces just 70 to 100 millivolts of potential electricity, which isn’t even enough to power a sensor or Wi-Fi chip, according to a report in the Wall Street Journal.
Makosinski, a high school sophomore at St. Michaels University School in Victoria, British Columbia, initially thought of the idea after learning that a friend in the Philippines, who didn’t have electricity, was failing in school because she didn’t have enough time to study during daylight hours. Her friend’s dilemma is surprisingly common among a growing number of people in developing regions that either can’t afford or don’t have access to a power grid. For Makosinski, it served as an impetus to apply what she had learned about energy-harvesting materials from experiments she’s been conducting since the seventh grade.