Not many kids can say they’re award-winning inventors—but Gitanjali Rao can. The seventh-grader from Lone Tree, Colorado, created a device that detects a poisonous chemical called lead in water. Last fall, she earned the top prize in the Discovery Education 3M Young Scientist Challenge. She won $25,000—and was named America’s Top Young Scientist.

“It was a dream coming true,” Gitanjali says.

She was inspired by a health crisis in Flint, Michigan. In 2014, its water system was contaminated with lead from city water pipes. Lead can cause health issues ranging from rashes to brain damage. Many people in Flint got sick after drinking the water or bathing in it without knowing it was unsafe. Most people in Flint have been using bottled water while they wait for their lead water pipes to be replaced.

Right now, the most accurate method to test for lead in water is to send water samples to a lab. But the test requires expensive equipment, and getting results can take more than a week. For faster results, people can buy test strips for use at home, but they aren’t always accurate. Gitanjali wanted to come up with a better test that is cheap, quick, and reliable.

She named her device Tethys, after the Greek goddess of fresh water. Tethys has a special sensor that can detect lead when the device is dipped in water. Within seconds, Tethys sends a reading to a smartphone app, which Gitanjali wrote the code for. 

Gitanjali says she will use some of her prize money to further develop Tethys. She hopes to start selling it within the next year. She also has some advice for other young inventors.

“Just keep trying and do not be afraid of failure,” she says.