Teenager invents flashlight powered by the warmth of your hand

http://www.nbcnews.com/technology/teenager-invents-flashlight-powered-warmth-your-hand-6C10485762

June 30, 2013

A 15-year-old girl has invented a flashlight that produces a usable amount of light just by using the heat from your hand. And if the judges at the Google Science Fair like it, she may be on her way to the grand prize.

Ann Makosinski of Canada entered another Science Fair last year with a flashlight that used kinetic energy to power its LEDs, and this year she wanted to try making one that worked via the thermoelectric effect. That's when a small amount of electricity can be harvested as electrons flow between the cool and hot sides of a material.

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The light generated is modest, but enough to find your keys or light the page of a book. It worked for around half an hour in her tests at an ambient temperature of about 50 degrees Fahrenheit, but would last longer or shorter depending on temperature differences.

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