What were you doing when you were 15? Probably not revolutionizing the way we deal with blackouts and coal mines and insert other dark place here. But maybe we should have been. After all, we’ve all had to decide between candles and flashlights when the power’s gone out, and both have the same exact handicap: they eventually run out.
Ann Makosinski, a 15-year-old student with Canada’s St. Michaels University School, has created a flashlight that is powered solely by the heat of a human hand. For this, she has been chosen as one of 15 finalists for Google’s global science fair.
She created the device using the idea of Peltier tiles, which are devices that create energy when one side is heated while the other side is cooled. Combining this, which created enough power, with a store-bought circuit, which provided enough voltage, she ended up with The Hollow Flashlight. Inside the flashlight is nothing but air, which acts as the cooling agent. So, wrap your hand around the outside, and you've got the necessary temperature duality.
It requires absolutely no outside power source, other than a human hand. And it only cost her $26. If they ever begin mass producing these things (and they really should), Makosinski thinks the flashlights can be made for even cheaper.
In the video below, Makosinski explains the process of building the flashlight.