Do you remember what you were doing when you were 15? Probably nothing as groundbreaking as Ann Makosinski. She designed a flashlight that's powered entirely by body heat.

The device, which she calls "hollow flashlight," uses Peltier tiles to transform hand warmth into usable energy. It's battery free and a typical light beam can last up to 20 minutes.

Makosinski was selected to bring her flashlight to the Google Science Fair on Sept. 21. She'll be among 14 other students that will compete to receive a $50,000 scholarship and a free trip to the Galapagos Islands. Check out her video below: