Science Fair Season

Kelydra Welcker doesn't consider herself a young Erin Brockovich. But after she exposed DuPont for releasing potentially harmful chemicals into the water of her West Virginia hometown, the comparison was natural. DuPont is the top employer in Parkersburg, a small city on the banks of the Ohio River. Welcker's father was a chemist there, her sister an engineer. So when, at 17, Welcker began collecting data on the levels of perfluorooctanoic acid (PFOA) seeping from the DuPont facility, her family was wary of what she might turn up.

PFOA, used in making Teflon, has been linked to cancer in lab animals, and Parkersburg residents had over five times more of it in their blood than the national average. Hit with a $10.25 million fine from the EPA two years earlier, DuPont had pledged to reduce its PFOA emissions. For her junior-year science fair project, Welcker decided to see if the company was making good.

At first it was. But four months after Welcker began her tests, PFOA levels began to rise. Welcker went on local TV to warn neighbors and teach them an easy trick for testing their water at home: "Just boil it and shake it," she'd say. If it bubbled, it meant PFOA was present. In her backyard laboratory, she built a device using windshield wipers, steel wool, and a six-volt battery that harnessed electricity to remove the acid from water through a process called electrosorption. She earned a patent for her invention, and some unforeseen notoriety. A documentary film crew caught wind of Welcker's research, and while shooting footage at the DuPont plant with Welcker in tow, raised suspicions of espionage that led an FBI agent to the Welckers' door. Filming a chemical plant, he said, is a breach of homeland security. Welcker was stunned. "I'm not attacking DuPont," she protested to her parents. "I'm helping them!"

Since then the company has cut emissions drastically and no longer considers Welcker a security threat. For her part, between studying chemistry at West Virginia Wesleyan College and applying to med school, Welcker still finds time to go home each month and test the waters.

Next: See 3 more of our favorite finalists with big ideas and even bigger hearts
Kayla Cornale

Photo: Corey Mihaliuk/Getty Images for CNN

The Maestro
Inspired by her autistic cousin, Lorena, Kayla Cornale created Sounds into Syllables, an educational program that uses musical lessons to teach autistic kids communication skills. Cornale appeared on CNN, along with Lorena, who delivered a sentiment she'd never been able to say before: "I love you, Kayla."
Garrett Yazzie

Photo: Courtesy of Garrett Yazzie

Heat Seeker
Garrett Yazzie's family lived in a singlewide trailer on a Navajo reservation in Arizona. Coal for the stove was expensive and aggravated his sister's asthma. But their cold nights came to an end when Garrett cobbled together a solar heater from a '67 Pontiac radiator and 69 soda cans, generating free, clean heat for his family.
Eliza McNitt

Photo: William Taufic Photography

Queen Bee
Eliza McNitt wanted to be an actress, not a scientist—until her class project revealed evidence supporting the theory that pesticides are contributing to the collapse of bee colonies worldwide, earning her high honors at the country's top fair. Now a film student, she makes documentaries about environmental issues.