MONKTON, Va. -- A young girl in Virginia has turned her fifth-grade science project into a life-changing hobby, but it's not her life she's changing, but those of other children.
From playing with her dog to her budding interest in lacrosse, Sierra Petrocelli is your average 11-year-old. She's a fifth-grader at Monkton Central School. She's a quiet kid, but not surprisingly to the people who know her well, Sierra has found an extraordinary hobby.
"Of course I'm a very proud mom," Lianne Petrocelli said.
Sierra develops prosthetic hands made from a 3D printer. The idea started when she wanted to use a 3D printer for her fifth-grade science project.
"I never thought I was going to actually build a hand," she said. "I thought I was just going to show pictures."
The printer lays down thin layers of plastic into a design made on a computer. Sierra connected with a company called E-Nable based in Chicago. The company makes the computer models of the hands for children. They sent Sierra a tutorial.
"To work it, you bend your wrist and it pulls these strings back and they go all the way through the fingers," she said.
Sierra's teacher was amazed when she heard about Sierra's ambitions for the project.
"I asked her to think about how 3D printing can change the world, improve something, change someone's life," Katie La Riviere-Gagner said.
More important than the "A" she received on her project is the way in which Sierra has decided to use her talent. She's making a new hand for an 8-year-old in California.
The hand that Sierra will create costs just $50. Compare that to a prosthetic bought from a hospital and thousands of dollars are saved.
"I think my favorite part is helping someone," Sierra said. "They can do more now and not just have to use one of their hands to do everything,"
Sierra and her family will travel to California later this year and they hope to meet the girl receiving the hand.
This self-described shy kid took her school assignment and turned it into a gift for others.
"That was the coolest project I think I've ever done," she said.