Many of us stash a flashlight for emergencies, only to find that when the time comes to use it, the batteries have run out. The problem of how to achieve efficient, lightweight energy storage plagues everything from flashlights to electric cars. But what if you could bypass it altogether? That’s what Ann Makosinski of Canada has done with her Hollow Flashlight, which won the 15-16 age group category of the Google Science Fair on Monday. Makosinksi’s flashlight runs on four Peltier tiles, which convert heat into energy using the temperature differential between a person’s hand and the ambient air.

“I chose to investigate the aspect of human energy when I found out that we are like walking 100-watt light bulbs,”