ARI SHAPIRO, HOST:
Now we have a profile of an inventor from Colorado. She's already made it onto the 2019 Forbes 30 Under 30 list for top young scientists, but she has not even made it to high school yet. She's 13. Her most famous invention so far - a mobile device that tests for lead in drinking water. Here's Colorado Public Radio's Michael Elizabeth Sakas.
MICHAEL ELIZABETH SAKAS, BYLINE: Gitanjali Rao opens her closet door and shows off her game collection.
GITANJALI RAO: So I'm slightly overly obsessed with board games, as you can probably see here.
SAKAS: A dozen or so are stacked roughly in her closet. She says her favorite is Clue because she wins. And her favorite character - Professor Plum.
RAO: He looks like somebody who would love science, and so I like him.
SAKAS: Because Rao definitely loves science. There's a pennant flag from MIT hanging on her bedroom wall. Her dream is to go there to study genetics. There's a desk not far from her bed which she calls her lab. It's complete with a 3D printer, test tubes.
RAO: And here's my inventor's notebook, which I love, a graduated cylinder. I've got a little box of lead (laughter).
SAKAS: And there's the lead detection device she designed and named Tethys after the Greek goddess of clean water. It's a 3D-printed box about the size of a deck of cards. So how does it work?
RAO: A carbon nanotube sensor detects the lead in the water and forms resistance.
SAKAS: OK. What she's saying is carbon atoms link together in kind of a beehive shape and then become a tube. Lead sticks to the carbon ions which creates resistance.
RAO: So I have a processor that measures the resistance and sends the data to a mobile phone once you connect over Bluetooth, and it gives you the status of the lead in your water.
SAKAS: Rao got the idea after reading about the same technology used to detect hazardous gas in the air.
RAO: And my immediate reaction was, why not use carbon nanotube sensors to detect the lead in waters? And that's a problem which I'd heard about three years ago during the Flint water crisis.
SAKAS: As a 12-year-old, she was named America's Top Young Scientist by Discovery Education, and she landed an interview on "The Tonight Show With Jimmy Fallon" (ph).
(SOUNDBITE OF TV SHOW, "THE TONIGHT SHOW STARRING JIMMY FALLON")
JIMMY FALLON: When I was 12, I don't know what I was thinking. I was lip-syncing in my mirror in my bedroom.
SAKAS: Rao says the fame helped her make friends at school when her family first moved to Colorado. Kids already knew who she was.
RAO: Oh, you're that lead girl, right? I'm like, yeah, I'm that lead girl. And they're like, do you want to be friends? I'm like, yeah, sure. Let's do this.
SAKAS: Now she's working to create a prototype of Tethys that could eventually be on the market, and she's getting help from scientists in the water industry. Rao stands at a whiteboard with Dr. Selene Hernandez Ruiz, a lab manager at Denver Water, Colorado's largest water utility. She's brainstorming with Rao on what they'll be working on that day.
RAO: Right now, I'm looking at interference with other chemicals in water apart from lead.
SAKAS: This partnership started when Hernandez Ruiz invited Rao to come work in the lab after Rao took a tour of Denver Water.
RAO: I hooked on, and I was like, hey, I want space in your lab. Can I come here, like, every day?
SAKAS: Hernandez Ruiz says she's thrilled to be helping a young woman of color foster a passion for science.
SELENE HERNANDEZ RUIZ: So hopeful to see the current and next generation like Gitanjali going for it so strong - right? - with all the right tools, with really the desire to excel and test those boundaries.
SAKAS: Rao hopes to get a prototype of her device out into the world in the next two years. In the meantime, she's filling up her inventors' notebook with new ideas. For NPR News, I'm Michael Elizabeth Sakas in Denver.
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