Fifteen-year-old Ann Makosinski has invented a hollow flashlight that uses no batteries, but instead is powered by the heat radiated from her palm.

The Canada native is currently in the 10th grade at St. Michaels University School in Victoria, British Columbia. Her invention has earned her a finalist spot in Google's Science Fair competition, which will announce the winners from three categories and one grand prize winner in September. Makosinski and the other 14 finalists will travel to Google's headquarters in Mountain View, Calif. for the ceremony, where the grand prize winner will be awarded a $50,000 scholarship from Google and a trip to the Galapagos Islands.

Makosinski has been competing in science fairs since the sixth grade, she says, and has developed a passion for researching alternative energy.

"I'm really interested in harvesting surplus energy, energy that surrounds but we never really use," Makosinski said in an interview last Thursday.

In her search for alternative energy sources, she stumbled upon the technology that would later become the foundation for her body heat-powered flashlight. They're called Peltier tiles, and they work by using contrasting temperatures to generate electricity.

Makosinski knew from prior calculations that the warmth of a person's hand was sufficient to power an LED. After purchasing the Peltier tiles on eBay, she ran tests to see if they generated enough power to light an LED. They did. In fact, they generated more than enough. However, she ran into problems because the tiles did not generate sufficient voltage.

She tinkered with the circuitry, but none of the adjustments seemed to make a difference. She found herself wanting to stop at times, but resolved herself to stay determined, reminding herself "You just kind of have to keep going," she said.

Months were spent fine-tuning the flashlight's circuit, retooling and reconfiguring the transformer she had built in order to boost the voltage. She pored over countless articles online about the process. But like any 15-year-old, her time was not unlimited.

"This took quite awhile 'cause I had to do it during the school year as well," she said. "And I had homework, plays, whatever that I was also doing."

Her shining moment eventually came when she read an article on energy harvesting, which suggested a circuit to try along with a recommended transformer. Makosinski heeded the advice and to her surprise, the circuit worked.

Physically, the flashlight is composed of two tubes — one aluminum and one PVC. The aluminum's properties enable it to sustain cooler temperatures in spite of a warmer environment. It sits inside the PVC tube, which provides further insulation. Makosinski also cut out a slit for the user's hand to touch the tiles.

The largest drawback in her current design is the temperature limitations. The flashlight performed better at 41 degrees than when she tested it than at 50 degrees, though she was able to maintain illumination for 20 minutes, she says — enough time to search for candles in a power outage or to go for a short walk.

She hopes with added popularity the current cost to produce one flashlight — $26 — could drop significantly, not to mention improve the quality of the circuit's components.

Makosinski learned about electronics from her father, who works as a laboratory manager at the mechanical shop at the University of Victoria where she obtained the flashlight's aluminum tube. Neither of her parents has a post-secondary degree in sciences; however, both support their daughter's passion for science, Makosinski said.

For now, she's looking forward to the trip to California in the fall, and potentially a second trip to the Galapagos, if all goes to plan.

"I just can't believe that I actually made it this far," she said.