This 12-year-old won $25,000 for an invention that helps detect lead in water

Twelve-year-old scientist Gitanjali Rao has been inventing since she was in kindergarten. Rao says that she has more than eight inventions, but it was Tethys — a 3D printed device that harnesses carbon nanotubes and a mobile app to test water for lead contamination in as little as 10 seconds — that won her the title of America’s Top Young Scientist, and $25,000.