A hollow flashlight powered by the heat from a user's hand, designed by a 15-year-old girl from Victoria, has been picked for the finals of the Google Science Fair.

Ann Makosinski, a Grade 10 student at St. Michaels University School in Victoria, is one of 15 students from around the world who beat out thousands of entries from more than 100 countries to earn their spot as finalists.

They will visit the Google campus in Mountain View, Calif., in September for the prize ceremony, Google announced Thursday. Winners will be chosen in three age categories, and one will receive the grand prize, which includes a $50,000 scholarship from Google and a trip to the Galapagos Islands.

Makosinski said she is excited about presenting to the Google Science Fair judges, many of whom are scientists, and being able to talk to the other finalists about their projects.

Makosinski has been submitting projects to science fairs since Grade 6, and has been particularly interested in alternative energy.

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

While researching different forms of alternative energy a few years ago, she learned about devices called Peltier tiles that produce electricity when heated on one side and cooled on the other. She experimented with such tiles for her Grade 7 science fair project and thought of them again as a way to potentially capture the thermal energy produced by the human body.

Makosinski did some calculations to see if the amount of energy produced by warmth from a person's hand was theoretically sufficient to power an LED bright enough to use in a flashlight, and she found it was more than enough.

Stumbling block

She bought Peltier tiles on eBay and tested them to see if they could produce sufficient power to light an LED. It turned out the power was more than enough, but the tiles generated only a fraction of the voltage needed. Further research suggested that if she made some changes to the design of the circuit, transformers could be used to boost the voltage.

Makosinski admitted there were points in the experiment when she thought it would never work, but said "You just kind of have to keep going."

She spent months doing research on the internet, experimented with different circuits and even built her own transformers, which still didn't provide enough voltage.

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

In the end, she came across an article on the web about energy harvesting that suggested an affordable circuit that would provide the voltage she needed when used with a recommended transformer, she said in an online report submitted to Google.

Finally, the circuit worked.

Steady beam of light

Makosinski made two different flashlights, each using a slightly different kind of Peltier tile, by assembling the electronics with other parts:

An aluminum tube, obtained from a mechanical shop at the University of Victoria, where her father works as a laboratory manager. The aluminum was used to transfer the cooler temperatures of the air to one side of the Peltier tiles.

A PVC tube from Home Depot used to house the aluminum tube, with an opening cut in it to allow a person's hand to come in contact with the other side of the Peltier tiles.

Makosinski tested the flashlights and found that both were brighter when the air temperature was 5 C than when it was 10 C, due to the bigger difference between body temperature and the air temperature. But even at 10 C, both flashlights maintained a steady beam of light for over 20 minutes, she reported.

In all, the materials for each flashlight cost about $26, she said, but she thinks that if it were mass produced, it could be manufactured and sold for a far lower price.

Neither of Makosinski's parents have a post-secondary science education, but they have encouraged her passion for science, she said. Her father helped her by teaching her the basics of electronics and ordering the parts she requested online.

Makosinski said she is looking forward to her upcoming trip, including the visit to Google's headquarters. She added, "I just can't believe that I actually made it this far."