A teenager from British Columbia recently invented a thermoelectric Hollow Flashlight that is able to be powered by the head of your hand.
Ann Makosinski, 15, designed the project for the Google Science Fair.
"My objective in my project was to create a flashlight that runs solely on the heat of the human hand. Using four Peltier tiles and the temperature difference between the palm of the hand and ambient air, I designed a flashlight that provides bright light without batteries or moving parts," she described in her project summary.
"My design is ergonomic, thermodynamically efficient, and only needs a five degree temperature difference to work and produce up to 5.4 mW at 5 foot candles of brightness."
Last year, she entered another science fair with a flashlight powered by kinetic energy. She was inspired by that design to make an even better flashlight able to run off heat.
Called the thermoelectric effect, it happens when a small amount of electricity is able to be harvested as electrons flow between the cool and hot sides of the material.
She was able to power the flashlight for thirty minutes at an ambient temperature of 50 degrees Fahrenheit.
"The flashlight I have made is more of a prototype than a final product, but the components in my device are quite strong," she said. "Of course, if it was to be used and manufactured, I would try to seal off the electronic components in some sort of casing so that it wouldn't get heavily exposed to the elements [example water], and therefore last longer."