Ask most teens about their plans for the future, and you’ll likely get a shrug. But Redmond’s Apoorv Khandelwal, 17, knows exactly what he wants to do. The Tesla STEM High School senior was one of 40 finalists in the 2017 Regeneron Science Talent Search (STS)—an honor coveted by young scientists nationwide—for his invention that removes salt from seawater. His goal: to bring drinkable water to millions of people in developing countries. The process is called reverse desalination.