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Using waste heat: 15-year old builds human-powered flashlight

Fifteen year old Ann Makosinski was  inspired when she was told that humans are “like walking 100-Watt bulbs.” She decided to harness that bulb in a human-powered flashlight.

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Fifteen year old Ann Makosinski was inspired when she was told that humans are "like walking 100-Watt bulbs." She decided to harness that bulb in a human-powered flashlight. By combining peltier tiles, a hollow aluminum tube, and a light-emitting diode (LED), the 10th graders was able to create a working flashlight powered by body heat. She got 2nd place in a science fair back home and then went on to win the 2013 Google Science Fair with her invention.

Peltier tiles generate electricity by converting thermal energy as it flows from a heat source to a cold source - that is, energy flowing from hot to cold. For those who haven't seen Ann's flashlight in action, check out this video:


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Skip to the last 11 seconds of this video to see the flashlight in action.

Photo credit: Graphic of a Peltier element by michbich and founds using Creative Commons.