In times of great emergency, a flashlight is definitely one of the essentials to have, aside from food and water. When the electricity is out and it’s night time, you might have to stay in place and wait for the sun to rise if you don’t have a torch with you. Of course, you might have one but not the right batteries to power it up, but you have the Any Battery Light to depend on in that scenario.
But what if you don’t have any good batteries at all? What then?
15-year-old Ann Makosinski probably considered that situation well and hard, and it led her to create a flashlight that only needs some body heat to function; specifically, heat from your hands. The device was made using Peltier tiles, which can create energy when one side of it is heated while the other is kept cool.
Ann put it together with a store-bought circuit, which provided enough voltage, and voila! That’s how the Hollow Flashlight came to be.
In this case, your hand provides the heat while the air inside the flashlight acts as the cooling agent. The entire thing only cost Ann $26(USD) to make!
Because of her Hollow Flashlight design, Ann is one of the finalists for Google’s global science fair.